tools/lib/bpf/libbpf.c

   1 // SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
   2
   3 /*
   4  * Common eBPF ELF object loading operations.
   5  *
   6  * Copyright (C) 2013-2015 Alexei Starovoitov <ast@kernel.org>
   7  * Copyright (C) 2015 Wang Nan <wangnan0@huawei.com>
   8  * Copyright (C) 2015 Huawei Inc.
   9  * Copyright (C) 2017 Nicira, Inc.
  10  * Copyright (C) 2019 Isovalent, Inc.
  11  */
  12
  13 #ifndef _GNU_SOURCE
  14 #define _GNU_SOURCE
  15 #endif
  16 #include <stdlib.h>
  17 #include <stdio.h>
  18 #include <stdarg.h>
  19 #include <libgen.h>
  20 #include <inttypes.h>
  21 #include <limits.h>
  22 #include <string.h>
  23 #include <unistd.h>
  24 #include <endian.h>
  25 #include <fcntl.h>
  26 #include <errno.h>
  27 #include <ctype.h>
  28 #include <asm/unistd.h>
  29 #include <linux/err.h>
  30 #include <linux/kernel.h>
  31 #include <linux/bpf.h>
  32 #include <linux/btf.h>
  33 #include <linux/filter.h>
  34 #include <linux/list.h>
  35 #include <linux/limits.h>
  36 #include <linux/perf_event.h>
  37 #include <linux/ring_buffer.h>
  38 #include <linux/version.h>
  39 #include <sys/epoll.h>
  40 #include <sys/ioctl.h>
  41 #include <sys/mman.h>
  42 #include <sys/stat.h>
  43 #include <sys/types.h>
  44 #include <sys/vfs.h>
  45 #include <sys/utsname.h>
  46 #include <sys/resource.h>
  47 #include <libelf.h>
  48 #include <gelf.h>
  49 #include <zlib.h>
  50
  51 #include "libbpf.h"
  52 #include "bpf.h"
  53 #include "btf.h"
  54 #include "str_error.h"
  55 #include "libbpf_internal.h"
  56 #include "hashmap.h"
  57 #include "bpf_gen_internal.h"
  58
  59 #ifndef BPF_FS_MAGIC
  60 #define BPF_FS_MAGIC            0xcafe4a11
  61 #endif
  62
  63 #define BPF_INSN_SZ (sizeof(struct bpf_insn))
  64
  65 /* vsprintf() in __base_pr() uses nonliteral format string. It may break
  66  * compilation if user enables corresponding warning. Disable it explicitly.
  67  */
  68 #pragma GCC diagnostic ignored "-Wformat-nonliteral"
  69
  70 #define __printf(a, b)  __attribute__((format(printf, a, b)))
  71
  72 static struct bpf_map *bpf_object__add_map(struct bpf_object *obj);
  73 static bool prog_is_subprog(const struct bpf_object *obj, const struct bpf_program *prog);
  74
  75 static int __base_pr(enum libbpf_print_level level, const char *format,
  76                      va_list args)
  77 {
  78         if (level == LIBBPF_DEBUG)
  79                 return 0;
  80
  81         return vfprintf(stderr, format, args);
  82 }
  83
  84 static libbpf_print_fn_t __libbpf_pr = __base_pr;
  85
  86 libbpf_print_fn_t libbpf_set_print(libbpf_print_fn_t fn)
  87 {
  88         libbpf_print_fn_t old_print_fn = __libbpf_pr;
  89
  90         __libbpf_pr = fn;
  91         return old_print_fn;
  92 }
  93
  94 __printf(2, 3)
  95 void libbpf_print(enum libbpf_print_level level, const char *format, ...)
  96 {
  97         va_list args;
  98
  99         if (!__libbpf_pr)
 100                 return;
 101
 102         va_start(args, format);
 103         __libbpf_pr(level, format, args);
 104         va_end(args);
 105 }
 106
 107 static void pr_perm_msg(int err)
 108 {
 109         struct rlimit limit;
 110         char buf[100];
 111
 112         if (err != -EPERM || geteuid() != 0)
 113                 return;
 114
 115         err = getrlimit(RLIMIT_MEMLOCK, &limit);
 116         if (err)
 117                 return;
 118
 119         if (limit.rlim_cur == RLIM_INFINITY)
 120                 return;
 121
 122         if (limit.rlim_cur < 1024)
 123                 snprintf(buf, sizeof(buf), "%zu bytes", (size_t)limit.rlim_cur);
 124         else if (limit.rlim_cur < 1024*1024)
 125                 snprintf(buf, sizeof(buf), "%.1f KiB", (double)limit.rlim_cur / 1024);
 126         else
 127                 snprintf(buf, sizeof(buf), "%.1f MiB", (double)limit.rlim_cur / (1024*1024));
 128
 129         pr_warn("permission error while running as root; try raising 'ulimit -l'? current value: %s\n",
 130                 buf);
 131 }
 132
 133 #define STRERR_BUFSIZE  128
 134
 135 /* Copied from tools/perf/util/util.h */
 136 #ifndef zfree
 137 # define zfree(ptr) ({ free(*ptr); *ptr = NULL; })
 138 #endif
 139
 140 #ifndef zclose
 141 # define zclose(fd) ({                  \
 142         int ___err = 0;                 \
 143         if ((fd) >= 0)                  \
 144                 ___err = close((fd));   \
 145         fd = -1;                        \
 146         ___err; })
 147 #endif
 148
 149 static inline __u64 ptr_to_u64(const void *ptr)
 150 {
 151         return (__u64) (unsigned long) ptr;
 152 }
 153
 154 /* this goes away in libbpf 1.0 */
 155 enum libbpf_strict_mode libbpf_mode = LIBBPF_STRICT_NONE;
 156
 157 int libbpf_set_strict_mode(enum libbpf_strict_mode mode)
 158 {
 159         /* __LIBBPF_STRICT_LAST is the last power-of-2 value used + 1, so to
 160          * get all possible values we compensate last +1, and then (2*x - 1)
 161          * to get the bit mask
 162          */
 163         if (mode != LIBBPF_STRICT_ALL
 164             && (mode & ~((__LIBBPF_STRICT_LAST - 1) * 2 - 1)))
 165                 return errno = EINVAL, -EINVAL;
 166
 167         libbpf_mode = mode;
 168         return 0;
 169 }
 170
 171 enum kern_feature_id {
 172         /* v4.14: kernel support for program & map names. */
 173         FEAT_PROG_NAME,
 174         /* v5.2: kernel support for global data sections. */
 175         FEAT_GLOBAL_DATA,
 176         /* BTF support */
 177         FEAT_BTF,
 178         /* BTF_KIND_FUNC and BTF_KIND_FUNC_PROTO support */
 179         FEAT_BTF_FUNC,
 180         /* BTF_KIND_VAR and BTF_KIND_DATASEC support */
 181         FEAT_BTF_DATASEC,
 182         /* BTF_FUNC_GLOBAL is supported */
 183         FEAT_BTF_GLOBAL_FUNC,
 184         /* BPF_F_MMAPABLE is supported for arrays */
 185         FEAT_ARRAY_MMAP,
 186         /* kernel support for expected_attach_type in BPF_PROG_LOAD */
 187         FEAT_EXP_ATTACH_TYPE,
 188         /* bpf_probe_read_{kernel,user}[_str] helpers */
 189         FEAT_PROBE_READ_KERN,
 190         /* BPF_PROG_BIND_MAP is supported */
 191         FEAT_PROG_BIND_MAP,
 192         /* Kernel support for module BTFs */
 193         FEAT_MODULE_BTF,
 194         /* BTF_KIND_FLOAT support */
 195         FEAT_BTF_FLOAT,
 196         __FEAT_CNT,
 197 };
 198
 199 static bool kernel_supports(const struct bpf_object *obj, enum kern_feature_id feat_id);
 200
 201 enum reloc_type {
 202         RELO_LD64,
 203         RELO_CALL,
 204         RELO_DATA,
 205         RELO_EXTERN_VAR,
 206         RELO_EXTERN_FUNC,
 207         RELO_SUBPROG_ADDR,
 208 };
 209
 210 struct reloc_desc {
 211         enum reloc_type type;
 212         int insn_idx;
 213         int map_idx;
 214         int sym_off;
 215 };
 216
 217 struct bpf_sec_def;
 218
 219 typedef struct bpf_link *(*attach_fn_t)(const struct bpf_sec_def *sec,
 220                                         struct bpf_program *prog);
 221
 222 struct bpf_sec_def {
 223         const char *sec;
 224         size_t len;
 225         enum bpf_prog_type prog_type;
 226         enum bpf_attach_type expected_attach_type;
 227         bool is_exp_attach_type_optional;
 228         bool is_attachable;
 229         bool is_attach_btf;
 230         bool is_sleepable;
 231         attach_fn_t attach_fn;
 232 };
 233
 234 /*
 235  * bpf_prog should be a better name but it has been used in
 236  * linux/filter.h.
 237  */
 238 struct bpf_program {
 239         const struct bpf_sec_def *sec_def;
 240         char *sec_name;
 241         size_t sec_idx;
 242         /* this program's instruction offset (in number of instructions)
 243          * within its containing ELF section
 244          */
 245         size_t sec_insn_off;
 246         /* number of original instructions in ELF section belonging to this
 247          * program, not taking into account subprogram instructions possible
 248          * appended later during relocation
 249          */
 250         size_t sec_insn_cnt;
 251         /* Offset (in number of instructions) of the start of instruction
 252          * belonging to this BPF program  within its containing main BPF
 253          * program. For the entry-point (main) BPF program, this is always
 254          * zero. For a sub-program, this gets reset before each of main BPF
 255          * programs are processed and relocated and is used to determined
 256          * whether sub-program was already appended to the main program, and
 257          * if yes, at which instruction offset.
 258          */
 259         size_t sub_insn_off;
 260
 261         char *name;
 262         /* sec_name with / replaced by _; makes recursive pinning
 263          * in bpf_object__pin_programs easier
 264          */
 265         char *pin_name;
 266
 267         /* instructions that belong to BPF program; insns[0] is located at
 268          * sec_insn_off instruction within its ELF section in ELF file, so
 269          * when mapping ELF file instruction index to the local instruction,
 270          * one needs to subtract sec_insn_off; and vice versa.
 271          */
 272         struct bpf_insn *insns;
 273         /* actual number of instruction in this BPF program's image; for
 274          * entry-point BPF programs this includes the size of main program
 275          * itself plus all the used sub-programs, appended at the end
 276          */
 277         size_t insns_cnt;
 278
 279         struct reloc_desc *reloc_desc;
 280         int nr_reloc;
 281         int log_level;
 282
 283         struct {
 284                 int nr;
 285                 int *fds;
 286         } instances;
 287         bpf_program_prep_t preprocessor;
 288
 289         struct bpf_object *obj;
 290         void *priv;
 291         bpf_program_clear_priv_t clear_priv;
 292
 293         bool load;
 294         bool mark_btf_static;
 295         enum bpf_prog_type type;
 296         enum bpf_attach_type expected_attach_type;
 297         int prog_ifindex;
 298         __u32 attach_btf_obj_fd;
 299         __u32 attach_btf_id;
 300         __u32 attach_prog_fd;
 301         void *func_info;
 302         __u32 func_info_rec_size;
 303         __u32 func_info_cnt;
 304
 305         void *line_info;
 306         __u32 line_info_rec_size;
 307         __u32 line_info_cnt;
 308         __u32 prog_flags;
 309 };
 310
 311 struct bpf_struct_ops {
 312         const char *tname;
 313         const struct btf_type *type;
 314         struct bpf_program **progs;
 315         __u32 *kern_func_off;
 316         /* e.g. struct tcp_congestion_ops in bpf_prog's btf format */
 317         void *data;
 318         /* e.g. struct bpf_struct_ops_tcp_congestion_ops in
 319          *      btf_vmlinux's format.
 320          * struct bpf_struct_ops_tcp_congestion_ops {
 321          *      [... some other kernel fields ...]
 322          *      struct tcp_congestion_ops data;
 323          * }
 324          * kern_vdata-size == sizeof(struct bpf_struct_ops_tcp_congestion_ops)
 325          * bpf_map__init_kern_struct_ops() will populate the "kern_vdata"
 326          * from "data".
 327          */
 328         void *kern_vdata;
 329         __u32 type_id;
 330 };
 331
 332 #define DATA_SEC ".data"
 333 #define BSS_SEC ".bss"
 334 #define RODATA_SEC ".rodata"
 335 #define KCONFIG_SEC ".kconfig"
 336 #define KSYMS_SEC ".ksyms"
 337 #define STRUCT_OPS_SEC ".struct_ops"
 338
 339 enum libbpf_map_type {
 340         LIBBPF_MAP_UNSPEC,
 341         LIBBPF_MAP_DATA,
 342         LIBBPF_MAP_BSS,
 343         LIBBPF_MAP_RODATA,
 344         LIBBPF_MAP_KCONFIG,
 345 };
 346
 347 static const char * const libbpf_type_to_btf_name[] = {
 348         [LIBBPF_MAP_DATA]       = DATA_SEC,
 349         [LIBBPF_MAP_BSS]        = BSS_SEC,
 350         [LIBBPF_MAP_RODATA]     = RODATA_SEC,
 351         [LIBBPF_MAP_KCONFIG]    = KCONFIG_SEC,
 352 };
 353
 354 struct bpf_map {
 355         char *name;
 356         int fd;
 357         int sec_idx;
 358         size_t sec_offset;
 359         int map_ifindex;
 360         int inner_map_fd;
 361         struct bpf_map_def def;
 362         __u32 numa_node;
 363         __u32 btf_var_idx;
 364         __u32 btf_key_type_id;
 365         __u32 btf_value_type_id;
 366         __u32 btf_vmlinux_value_type_id;
 367         void *priv;
 368         bpf_map_clear_priv_t clear_priv;
 369         enum libbpf_map_type libbpf_type;
 370         void *mmaped;
 371         struct bpf_struct_ops *st_ops;
 372         struct bpf_map *inner_map;
 373         void **init_slots;
 374         int init_slots_sz;
 375         char *pin_path;
 376         bool pinned;
 377         bool reused;
 378 };
 379
 380 enum extern_type {
 381         EXT_UNKNOWN,
 382         EXT_KCFG,
 383         EXT_KSYM,
 384 };
 385
 386 enum kcfg_type {
 387         KCFG_UNKNOWN,
 388         KCFG_CHAR,
 389         KCFG_BOOL,
 390         KCFG_INT,
 391         KCFG_TRISTATE,
 392         KCFG_CHAR_ARR,
 393 };
 394
 395 struct extern_desc {
 396         enum extern_type type;
 397         int sym_idx;
 398         int btf_id;
 399         int sec_btf_id;
 400         const char *name;
 401         bool is_set;
 402         bool is_weak;
 403         union {
 404                 struct {
 405                         enum kcfg_type type;
 406                         int sz;
 407                         int align;
 408                         int data_off;
 409                         bool is_signed;
 410                 } kcfg;
 411                 struct {
 412                         unsigned long long addr;
 413
 414                         /* target btf_id of the corresponding kernel var. */
 415                         int kernel_btf_obj_fd;
 416                         int kernel_btf_id;
 417
 418                         /* local btf_id of the ksym extern's type. */
 419                         __u32 type_id;
 420                 } ksym;
 421         };
 422 };
 423
 424 static LIST_HEAD(bpf_objects_list);
 425
 426 struct module_btf {
 427         struct btf *btf;
 428         char *name;
 429         __u32 id;
 430         int fd;
 431 };
 432
 433 struct bpf_object {
 434         char name[BPF_OBJ_NAME_LEN];
 435         char license[64];
 436         __u32 kern_version;
 437
 438         struct bpf_program *programs;
 439         size_t nr_programs;
 440         struct bpf_map *maps;
 441         size_t nr_maps;
 442         size_t maps_cap;
 443
 444         char *kconfig;
 445         struct extern_desc *externs;
 446         int nr_extern;
 447         int kconfig_map_idx;
 448         int rodata_map_idx;
 449
 450         bool loaded;
 451         bool has_subcalls;
 452
 453         struct bpf_gen *gen_loader;
 454
 455         /*
 456          * Information when doing elf related work. Only valid if fd
 457          * is valid.
 458          */
 459         struct {
 460                 int fd;
 461                 const void *obj_buf;
 462                 size_t obj_buf_sz;
 463                 Elf *elf;
 464                 GElf_Ehdr ehdr;
 465                 Elf_Data *symbols;
 466                 Elf_Data *data;
 467                 Elf_Data *rodata;
 468                 Elf_Data *bss;
 469                 Elf_Data *st_ops_data;
 470                 size_t shstrndx; /* section index for section name strings */
 471                 size_t strtabidx;
 472                 struct {
 473                         GElf_Shdr shdr;
 474                         Elf_Data *data;
 475                 } *reloc_sects;
 476                 int nr_reloc_sects;
 477                 int maps_shndx;
 478                 int btf_maps_shndx;
 479                 __u32 btf_maps_sec_btf_id;
 480                 int text_shndx;
 481                 int symbols_shndx;
 482                 int data_shndx;
 483                 int rodata_shndx;
 484                 int bss_shndx;
 485                 int st_ops_shndx;
 486         } efile;
 487         /*
 488          * All loaded bpf_object is linked in a list, which is
 489          * hidden to caller. bpf_objects__<func> handlers deal with
 490          * all objects.
 491          */
 492         struct list_head list;
 493
 494         struct btf *btf;
 495         struct btf_ext *btf_ext;
 496
 497         /* Parse and load BTF vmlinux if any of the programs in the object need
 498          * it at load time.
 499          */
 500         struct btf *btf_vmlinux;
 501         /* vmlinux BTF override for CO-RE relocations */
 502         struct btf *btf_vmlinux_override;
 503         /* Lazily initialized kernel module BTFs */
 504         struct module_btf *btf_modules;
 505         bool btf_modules_loaded;
 506         size_t btf_module_cnt;
 507         size_t btf_module_cap;
 508
 509         void *priv;
 510         bpf_object_clear_priv_t clear_priv;
 511
 512         char path[];
 513 };
 514 #define obj_elf_valid(o)        ((o)->efile.elf)
 515
 516 static const char *elf_sym_str(const struct bpf_object *obj, size_t off);
 517 static const char *elf_sec_str(const struct bpf_object *obj, size_t off);
 518 static Elf_Scn *elf_sec_by_idx(const struct bpf_object *obj, size_t idx);
 519 static Elf_Scn *elf_sec_by_name(const struct bpf_object *obj, const char *name);
 520 static int elf_sec_hdr(const struct bpf_object *obj, Elf_Scn *scn, GElf_Shdr *hdr);
 521 static const char *elf_sec_name(const struct bpf_object *obj, Elf_Scn *scn);
 522 static Elf_Data *elf_sec_data(const struct bpf_object *obj, Elf_Scn *scn);
 523
 524 void bpf_program__unload(struct bpf_program *prog)
 525 {
 526         int i;
 527
 528         if (!prog)
 529                 return;
 530
 531         /*
 532          * If the object is opened but the program was never loaded,
 533          * it is possible that prog->instances.nr == -1.
 534          */
 535         if (prog->instances.nr > 0) {
 536                 for (i = 0; i < prog->instances.nr; i++)
 537                         zclose(prog->instances.fds[i]);
 538         } else if (prog->instances.nr != -1) {
 539                 pr_warn("Internal error: instances.nr is %d\n",
 540                         prog->instances.nr);
 541         }
 542
 543         prog->instances.nr = -1;
 544         zfree(&prog->instances.fds);
 545
 546         zfree(&prog->func_info);
 547         zfree(&prog->line_info);
 548 }
 549
 550 static void bpf_program__exit(struct bpf_program *prog)
 551 {
 552         if (!prog)
 553                 return;
 554
 555         if (prog->clear_priv)
 556                 prog->clear_priv(prog, prog->priv);
 557
 558         prog->priv = NULL;
 559         prog->clear_priv = NULL;
 560
 561         bpf_program__unload(prog);
 562         zfree(&prog->name);
 563         zfree(&prog->sec_name);
 564         zfree(&prog->pin_name);
 565         zfree(&prog->insns);
 566         zfree(&prog->reloc_desc);
 567
 568         prog->nr_reloc = 0;
 569         prog->insns_cnt = 0;
 570         prog->sec_idx = -1;
 571 }
 572
 573 static char *__bpf_program__pin_name(struct bpf_program *prog)
 574 {
 575         char *name, *p;
 576
 577         name = p = strdup(prog->sec_name);
 578         while ((p = strchr(p, '/')))
 579                 *p = '_';
 580
 581         return name;
 582 }
 583
 584 static bool insn_is_subprog_call(const struct bpf_insn *insn)
 585 {
 586         return BPF_CLASS(insn->code) == BPF_JMP &&
 587                BPF_OP(insn->code) == BPF_CALL &&
 588                BPF_SRC(insn->code) == BPF_K &&
 589                insn->src_reg == BPF_PSEUDO_CALL &&
 590                insn->dst_reg == 0 &&
 591                insn->off == 0;
 592 }
 593
 594 static bool is_ldimm64_insn(struct bpf_insn *insn)
 595 {
 596         return insn->code == (BPF_LD | BPF_IMM | BPF_DW);
 597 }
 598
 599 static bool is_call_insn(const struct bpf_insn *insn)
 600 {
 601         return insn->code == (BPF_JMP | BPF_CALL);
 602 }
 603
 604 static bool insn_is_pseudo_func(struct bpf_insn *insn)
 605 {
 606         return is_ldimm64_insn(insn) && insn->src_reg == BPF_PSEUDO_FUNC;
 607 }
 608
 609 static int
 610 bpf_object__init_prog(struct bpf_object *obj, struct bpf_program *prog,
 611                       const char *name, size_t sec_idx, const char *sec_name,
 612                       size_t sec_off, void *insn_data, size_t insn_data_sz)
 613 {
 614         if (insn_data_sz == 0 || insn_data_sz % BPF_INSN_SZ || sec_off % BPF_INSN_SZ) {
 615                 pr_warn("sec '%s': corrupted program '%s', offset %zu, size %zu\n",
 616                         sec_name, name, sec_off, insn_data_sz);
 617                 return -EINVAL;
 618         }
 619
 620         memset(prog, 0, sizeof(*prog));
 621         prog->obj = obj;
 622
 623         prog->sec_idx = sec_idx;
 624         prog->sec_insn_off = sec_off / BPF_INSN_SZ;
 625         prog->sec_insn_cnt = insn_data_sz / BPF_INSN_SZ;
 626         /* insns_cnt can later be increased by appending used subprograms */
 627         prog->insns_cnt = prog->sec_insn_cnt;
 628
 629         prog->type = BPF_PROG_TYPE_UNSPEC;
 630         prog->load = true;
 631
 632         prog->instances.fds = NULL;
 633         prog->instances.nr = -1;
 634
 635         prog->sec_name = strdup(sec_name);
 636         if (!prog->sec_name)
 637                 goto errout;
 638
 639         prog->name = strdup(name);
 640         if (!prog->name)
 641                 goto errout;
 642
 643         prog->pin_name = __bpf_program__pin_name(prog);
 644         if (!prog->pin_name)
 645                 goto errout;
 646
 647         prog->insns = malloc(insn_data_sz);
 648         if (!prog->insns)
 649                 goto errout;
 650         memcpy(prog->insns, insn_data, insn_data_sz);
 651
 652         return 0;
 653 errout:
 654         pr_warn("sec '%s': failed to allocate memory for prog '%s'\n", sec_name, name);
 655         bpf_program__exit(prog);
 656         return -ENOMEM;
 657 }
 658
 659 static int
 660 bpf_object__add_programs(struct bpf_object *obj, Elf_Data *sec_data,
 661                          const char *sec_name, int sec_idx)
 662 {
 663         Elf_Data *symbols = obj->efile.symbols;
 664         struct bpf_program *prog, *progs;
 665         void *data = sec_data->d_buf;
 666         size_t sec_sz = sec_data->d_size, sec_off, prog_sz, nr_syms;
 667         int nr_progs, err, i;
 668         const char *name;
 669         GElf_Sym sym;
 670
 671         progs = obj->programs;
 672         nr_progs = obj->nr_programs;
 673         nr_syms = symbols->d_size / sizeof(GElf_Sym);
 674         sec_off = 0;
 675
 676         for (i = 0; i < nr_syms; i++) {
 677                 if (!gelf_getsym(symbols, i, &sym))
 678                         continue;
 679                 if (sym.st_shndx != sec_idx)
 680                         continue;
 681                 if (GELF_ST_TYPE(sym.st_info) != STT_FUNC)
 682                         continue;
 683
 684                 prog_sz = sym.st_size;
 685                 sec_off = sym.st_value;
 686
 687                 name = elf_sym_str(obj, sym.st_name);
 688                 if (!name) {
 689                         pr_warn("sec '%s': failed to get symbol name for offset %zu\n",
 690                                 sec_name, sec_off);
 691                         return -LIBBPF_ERRNO__FORMAT;
 692                 }
 693
 694                 if (sec_off + prog_sz > sec_sz) {
 695                         pr_warn("sec '%s': program at offset %zu crosses section boundary\n",
 696                                 sec_name, sec_off);
 697                         return -LIBBPF_ERRNO__FORMAT;
 698                 }
 699
 700                 if (sec_idx != obj->efile.text_shndx && GELF_ST_BIND(sym.st_info) == STB_LOCAL) {
 701                         pr_warn("sec '%s': program '%s' is static and not supported\n", sec_name, name);
 702                         return -ENOTSUP;
 703                 }
 704
 705                 pr_debug("sec '%s': found program '%s' at insn offset %zu (%zu bytes), code size %zu insns (%zu bytes)\n",
 706                          sec_name, name, sec_off / BPF_INSN_SZ, sec_off, prog_sz / BPF_INSN_SZ, prog_sz);
 707
 708                 progs = libbpf_reallocarray(progs, nr_progs + 1, sizeof(*progs));
 709                 if (!progs) {
 710                         /*
 711                          * In this case the original obj->programs
 712                          * is still valid, so don't need special treat for
 713                          * bpf_close_object().
 714                          */
 715                         pr_warn("sec '%s': failed to alloc memory for new program '%s'\n",
 716                                 sec_name, name);
 717                         return -ENOMEM;
 718                 }
 719                 obj->programs = progs;
 720
 721                 prog = &progs[nr_progs];
 722
 723                 err = bpf_object__init_prog(obj, prog, name, sec_idx, sec_name,
 724                                             sec_off, data + sec_off, prog_sz);
 725                 if (err)
 726                         return err;
 727
 728                 /* if function is a global/weak symbol, but has restricted
 729                  * (STV_HIDDEN or STV_INTERNAL) visibility, mark its BTF FUNC
 730                  * as static to enable more permissive BPF verification mode
 731                  * with more outside context available to BPF verifier
 732                  */
 733                 if (GELF_ST_BIND(sym.st_info) != STB_LOCAL
 734                     && (GELF_ST_VISIBILITY(sym.st_other) == STV_HIDDEN
 735                         || GELF_ST_VISIBILITY(sym.st_other) == STV_INTERNAL))
 736                         prog->mark_btf_static = true;
 737
 738                 nr_progs++;
 739                 obj->nr_programs = nr_progs;
 740         }
 741
 742         return 0;
 743 }
 744
 745 static __u32 get_kernel_version(void)
 746 {
 747         __u32 major, minor, patch;
 748         struct utsname info;
 749
 750         uname(&info);
 751         if (sscanf(info.release, "%u.%u.%u", &major, &minor, &patch) != 3)
 752                 return 0;
 753         return KERNEL_VERSION(major, minor, patch);
 754 }
 755
 756 static const struct btf_member *
 757 find_member_by_offset(const struct btf_type *t, __u32 bit_offset)
 758 {
 759         struct btf_member *m;
 760         int i;
 761
 762         for (i = 0, m = btf_members(t); i < btf_vlen(t); i++, m++) {
 763                 if (btf_member_bit_offset(t, i) == bit_offset)
 764                         return m;
 765         }
 766
 767         return NULL;
 768 }
 769
 770 static const struct btf_member *
 771 find_member_by_name(const struct btf *btf, const struct btf_type *t,
 772                     const char *name)
 773 {
 774         struct btf_member *m;
 775         int i;
 776
 777         for (i = 0, m = btf_members(t); i < btf_vlen(t); i++, m++) {
 778                 if (!strcmp(btf__name_by_offset(btf, m->name_off), name))
 779                         return m;
 780         }
 781
 782         return NULL;
 783 }
 784
 785 #define STRUCT_OPS_VALUE_PREFIX "bpf_struct_ops_"
 786 static int find_btf_by_prefix_kind(const struct btf *btf, const char *prefix,
 787                                    const char *name, __u32 kind);
 788
 789 static int
 790 find_struct_ops_kern_types(const struct btf *btf, const char *tname,
 791                            const struct btf_type **type, __u32 *type_id,
 792                            const struct btf_type **vtype, __u32 *vtype_id,
 793                            const struct btf_member **data_member)
 794 {
 795         const struct btf_type *kern_type, *kern_vtype;
 796         const struct btf_member *kern_data_member;
 797         __s32 kern_vtype_id, kern_type_id;
 798         __u32 i;
 799
 800         kern_type_id = btf__find_by_name_kind(btf, tname, BTF_KIND_STRUCT);
 801         if (kern_type_id < 0) {
 802                 pr_warn("struct_ops init_kern: struct %s is not found in kernel BTF\n",
 803                         tname);
 804                 return kern_type_id;
 805         }
 806         kern_type = btf__type_by_id(btf, kern_type_id);
 807
 808         /* Find the corresponding "map_value" type that will be used
 809          * in map_update(BPF_MAP_TYPE_STRUCT_OPS).  For example,
 810          * find "struct bpf_struct_ops_tcp_congestion_ops" from the
 811          * btf_vmlinux.
 812          */
 813         kern_vtype_id = find_btf_by_prefix_kind(btf, STRUCT_OPS_VALUE_PREFIX,
 814                                                 tname, BTF_KIND_STRUCT);
 815         if (kern_vtype_id < 0) {
 816                 pr_warn("struct_ops init_kern: struct %s%s is not found in kernel BTF\n",
 817                         STRUCT_OPS_VALUE_PREFIX, tname);
 818                 return kern_vtype_id;
 819         }
 820         kern_vtype = btf__type_by_id(btf, kern_vtype_id);
 821
 822         /* Find "struct tcp_congestion_ops" from
 823          * struct bpf_struct_ops_tcp_congestion_ops {
 824          *      [ ... ]
 825          *      struct tcp_congestion_ops data;
 826          * }
 827          */
 828         kern_data_member = btf_members(kern_vtype);
 829         for (i = 0; i < btf_vlen(kern_vtype); i++, kern_data_member++) {
 830                 if (kern_data_member->type == kern_type_id)
 831                         break;
 832         }
 833         if (i == btf_vlen(kern_vtype)) {
 834                 pr_warn("struct_ops init_kern: struct %s data is not found in struct %s%s\n",
 835                         tname, STRUCT_OPS_VALUE_PREFIX, tname);
 836                 return -EINVAL;
 837         }
 838
 839         *type = kern_type;
 840         *type_id = kern_type_id;
 841         *vtype = kern_vtype;
 842         *vtype_id = kern_vtype_id;
 843         *data_member = kern_data_member;
 844
 845         return 0;
 846 }
 847
 848 static bool bpf_map__is_struct_ops(const struct bpf_map *map)
 849 {
 850         return map->def.type == BPF_MAP_TYPE_STRUCT_OPS;
 851 }
 852
 853 /* Init the map's fields that depend on kern_btf */
 854 static int bpf_map__init_kern_struct_ops(struct bpf_map *map,
 855                                          const struct btf *btf,
 856                                          const struct btf *kern_btf)
 857 {
 858         const struct btf_member *member, *kern_member, *kern_data_member;
 859         const struct btf_type *type, *kern_type, *kern_vtype;
 860         __u32 i, kern_type_id, kern_vtype_id, kern_data_off;
 861         struct bpf_struct_ops *st_ops;
 862         void *data, *kern_data;
 863         const char *tname;
 864         int err;
 865
 866         st_ops = map->st_ops;
 867         type = st_ops->type;
 868         tname = st_ops->tname;
 869         err = find_struct_ops_kern_types(kern_btf, tname,
 870                                          &kern_type, &kern_type_id,
 871                                          &kern_vtype, &kern_vtype_id,
 872                                          &kern_data_member);
 873         if (err)
 874                 return err;
 875
 876         pr_debug("struct_ops init_kern %s: type_id:%u kern_type_id:%u kern_vtype_id:%u\n",
 877                  map->name, st_ops->type_id, kern_type_id, kern_vtype_id);
 878
 879         map->def.value_size = kern_vtype->size;
 880         map->btf_vmlinux_value_type_id = kern_vtype_id;
 881
 882         st_ops->kern_vdata = calloc(1, kern_vtype->size);
 883         if (!st_ops->kern_vdata)
 884                 return -ENOMEM;
 885
 886         data = st_ops->data;
 887         kern_data_off = kern_data_member->offset / 8;
 888         kern_data = st_ops->kern_vdata + kern_data_off;
 889
 890         member = btf_members(type);
 891         for (i = 0; i < btf_vlen(type); i++, member++) {
 892                 const struct btf_type *mtype, *kern_mtype;
 893                 __u32 mtype_id, kern_mtype_id;
 894                 void *mdata, *kern_mdata;
 895                 __s64 msize, kern_msize;
 896                 __u32 moff, kern_moff;
 897                 __u32 kern_member_idx;
 898                 const char *mname;
 899
 900                 mname = btf__name_by_offset(btf, member->name_off);
 901                 kern_member = find_member_by_name(kern_btf, kern_type, mname);
 902                 if (!kern_member) {
 903                         pr_warn("struct_ops init_kern %s: Cannot find member %s in kernel BTF\n",
 904                                 map->name, mname);
 905                         return -ENOTSUP;
 906                 }
 907
 908                 kern_member_idx = kern_member - btf_members(kern_type);
 909                 if (btf_member_bitfield_size(type, i) ||
 910                     btf_member_bitfield_size(kern_type, kern_member_idx)) {
 911                         pr_warn("struct_ops init_kern %s: bitfield %s is not supported\n",
 912                                 map->name, mname);
 913                         return -ENOTSUP;
 914                 }
 915
 916                 moff = member->offset / 8;
 917                 kern_moff = kern_member->offset / 8;
 918
 919                 mdata = data + moff;
 920                 kern_mdata = kern_data + kern_moff;
 921
 922                 mtype = skip_mods_and_typedefs(btf, member->type, &mtype_id);
 923                 kern_mtype = skip_mods_and_typedefs(kern_btf, kern_member->type,
 924                                                     &kern_mtype_id);
 925                 if (BTF_INFO_KIND(mtype->info) !=
 926                     BTF_INFO_KIND(kern_mtype->info)) {
 927                         pr_warn("struct_ops init_kern %s: Unmatched member type %s %u != %u(kernel)\n",
 928                                 map->name, mname, BTF_INFO_KIND(mtype->info),
 929                                 BTF_INFO_KIND(kern_mtype->info));
 930                         return -ENOTSUP;
 931                 }
 932
 933                 if (btf_is_ptr(mtype)) {
 934                         struct bpf_program *prog;
 935
 936                         prog = st_ops->progs[i];
 937                         if (!prog)
 938                                 continue;
 939
 940                         kern_mtype = skip_mods_and_typedefs(kern_btf,
 941                                                             kern_mtype->type,
 942                                                             &kern_mtype_id);
 943
 944                         /* mtype->type must be a func_proto which was
 945                          * guaranteed in bpf_object__collect_st_ops_relos(),
 946                          * so only check kern_mtype for func_proto here.
 947                          */
 948                         if (!btf_is_func_proto(kern_mtype)) {
 949                                 pr_warn("struct_ops init_kern %s: kernel member %s is not a func ptr\n",
 950                                         map->name, mname);
 951                                 return -ENOTSUP;
 952                         }
 953
 954                         prog->attach_btf_id = kern_type_id;
 955                         prog->expected_attach_type = kern_member_idx;
 956
 957                         st_ops->kern_func_off[i] = kern_data_off + kern_moff;
 958
 959                         pr_debug("struct_ops init_kern %s: func ptr %s is set to prog %s from data(+%u) to kern_data(+%u)\n",
 960                                  map->name, mname, prog->name, moff,
 961                                  kern_moff);
 962
 963                         continue;
 964                 }
 965
 966                 msize = btf__resolve_size(btf, mtype_id);
 967                 kern_msize = btf__resolve_size(kern_btf, kern_mtype_id);
 968                 if (msize < 0 || kern_msize < 0 || msize != kern_msize) {
 969                         pr_warn("struct_ops init_kern %s: Error in size of member %s: %zd != %zd(kernel)\n",
 970                                 map->name, mname, (ssize_t)msize,
 971                                 (ssize_t)kern_msize);
 972                         return -ENOTSUP;
 973                 }
 974
 975                 pr_debug("struct_ops init_kern %s: copy %s %u bytes from data(+%u) to kern_data(+%u)\n",
 976                          map->name, mname, (unsigned int)msize,
 977                          moff, kern_moff);
 978                 memcpy(kern_mdata, mdata, msize);
 979         }
 980
 981         return 0;
 982 }
 983
 984 static int bpf_object__init_kern_struct_ops_maps(struct bpf_object *obj)
 985 {
 986         struct bpf_map *map;
 987         size_t i;
 988         int err;
 989
 990         for (i = 0; i < obj->nr_maps; i++) {
 991                 map = &obj->maps[i];
 992
 993                 if (!bpf_map__is_struct_ops(map))
 994                         continue;
 995
 996                 err = bpf_map__init_kern_struct_ops(map, obj->btf,
 997                                                     obj->btf_vmlinux);
 998                 if (err)
 999                         return err;
1000         }
1001
1002         return 0;
1003 }
1004
1005 static int bpf_object__init_struct_ops_maps(struct bpf_object *obj)
1006 {
1007         const struct btf_type *type, *datasec;
1008         const struct btf_var_secinfo *vsi;
1009         struct bpf_struct_ops *st_ops;
1010         const char *tname, *var_name;
1011         __s32 type_id, datasec_id;
1012         const struct btf *btf;
1013         struct bpf_map *map;
1014         __u32 i;
1015
1016         if (obj->efile.st_ops_shndx == -1)
1017                 return 0;
1018
1019         btf = obj->btf;
1020         datasec_id = btf__find_by_name_kind(btf, STRUCT_OPS_SEC,
1021                                             BTF_KIND_DATASEC);
1022         if (datasec_id < 0) {
1023                 pr_warn("struct_ops init: DATASEC %s not found\n",
1024                         STRUCT_OPS_SEC);
1025                 return -EINVAL;
1026         }
1027
1028         datasec = btf__type_by_id(btf, datasec_id);
1029         vsi = btf_var_secinfos(datasec);
1030         for (i = 0; i < btf_vlen(datasec); i++, vsi++) {
1031                 type = btf__type_by_id(obj->btf, vsi->type);
1032                 var_name = btf__name_by_offset(obj->btf, type->name_off);
1033
1034                 type_id = btf__resolve_type(obj->btf, vsi->type);
1035                 if (type_id < 0) {
1036                         pr_warn("struct_ops init: Cannot resolve var type_id %u in DATASEC %s\n",
1037                                 vsi->type, STRUCT_OPS_SEC);
1038                         return -EINVAL;
1039                 }
1040
1041                 type = btf__type_by_id(obj->btf, type_id);
1042                 tname = btf__name_by_offset(obj->btf, type->name_off);
1043                 if (!tname[0]) {
1044                         pr_warn("struct_ops init: anonymous type is not supported\n");
1045                         return -ENOTSUP;
1046                 }
1047                 if (!btf_is_struct(type)) {
1048                         pr_warn("struct_ops init: %s is not a struct\n", tname);
1049                         return -EINVAL;
1050                 }
1051
1052                 map = bpf_object__add_map(obj);
1053                 if (IS_ERR(map))
1054                         return PTR_ERR(map);
1055
1056                 map->sec_idx = obj->efile.st_ops_shndx;
1057                 map->sec_offset = vsi->offset;
1058                 map->name = strdup(var_name);
1059                 if (!map->name)
1060                         return -ENOMEM;
1061
1062                 map->def.type = BPF_MAP_TYPE_STRUCT_OPS;
1063                 map->def.key_size = sizeof(int);
1064                 map->def.value_size = type->size;
1065                 map->def.max_entries = 1;
1066
1067                 map->st_ops = calloc(1, sizeof(*map->st_ops));
1068                 if (!map->st_ops)
1069                         return -ENOMEM;
1070                 st_ops = map->st_ops;
1071                 st_ops->data = malloc(type->size);
1072                 st_ops->progs = calloc(btf_vlen(type), sizeof(*st_ops->progs));
1073                 st_ops->kern_func_off = malloc(btf_vlen(type) *
1074                                                sizeof(*st_ops->kern_func_off));
1075                 if (!st_ops->data || !st_ops->progs || !st_ops->kern_func_off)
1076                         return -ENOMEM;
1077
1078                 if (vsi->offset + type->size > obj->efile.st_ops_data->d_size) {
1079                         pr_warn("struct_ops init: var %s is beyond the end of DATASEC %s\n",
1080                                 var_name, STRUCT_OPS_SEC);
1081                         return -EINVAL;
1082                 }
1083
1084                 memcpy(st_ops->data,
1085                        obj->efile.st_ops_data->d_buf + vsi->offset,
1086                        type->size);
1087                 st_ops->tname = tname;
1088                 st_ops->type = type;
1089                 st_ops->type_id = type_id;
1090
1091                 pr_debug("struct_ops init: struct %s(type_id=%u) %s found at offset %u\n",
1092                          tname, type_id, var_name, vsi->offset);
1093         }
1094
1095         return 0;
1096 }
1097
1098 static struct bpf_object *bpf_object__new(const char *path,
1099                                           const void *obj_buf,
1100                                           size_t obj_buf_sz,
1101                                           const char *obj_name)
1102 {
1103         struct bpf_object *obj;
1104         char *end;
1105
1106         obj = calloc(1, sizeof(struct bpf_object) + strlen(path) + 1);
1107         if (!obj) {
1108                 pr_warn("alloc memory failed for %s\n", path);
1109                 return ERR_PTR(-ENOMEM);
1110         }
1111
1112         strcpy(obj->path, path);
1113         if (obj_name) {
1114                 strncpy(obj->name, obj_name, sizeof(obj->name) - 1);
1115                 obj->name[sizeof(obj->name) - 1] = 0;
1116         } else {
1117                 /* Using basename() GNU version which doesn't modify arg. */
1118                 strncpy(obj->name, basename((void *)path),
1119                         sizeof(obj->name) - 1);
1120                 end = strchr(obj->name, '.');
1121                 if (end)
1122                         *end = 0;
1123         }
1124
1125         obj->efile.fd = -1;
1126         /*
1127          * Caller of this function should also call
1128          * bpf_object__elf_finish() after data collection to return
1129          * obj_buf to user. If not, we should duplicate the buffer to
1130          * avoid user freeing them before elf finish.
1131          */
1132         obj->efile.obj_buf = obj_buf;
1133         obj->efile.obj_buf_sz = obj_buf_sz;
1134         obj->efile.maps_shndx = -1;
1135         obj->efile.btf_maps_shndx = -1;
1136         obj->efile.data_shndx = -1;
1137         obj->efile.rodata_shndx = -1;
1138         obj->efile.bss_shndx = -1;
1139         obj->efile.st_ops_shndx = -1;
1140         obj->kconfig_map_idx = -1;
1141         obj->rodata_map_idx = -1;
1142
1143         obj->kern_version = get_kernel_version();
1144         obj->loaded = false;
1145
1146         INIT_LIST_HEAD(&obj->list);
1147         list_add(&obj->list, &bpf_objects_list);
1148         return obj;
1149 }
1150
1151 static void bpf_object__elf_finish(struct bpf_object *obj)
1152 {
1153         if (!obj_elf_valid(obj))
1154                 return;
1155
1156         if (obj->efile.elf) {
1157                 elf_end(obj->efile.elf);
1158                 obj->efile.elf = NULL;
1159         }
1160         obj->efile.symbols = NULL;
1161         obj->efile.data = NULL;
1162         obj->efile.rodata = NULL;
1163         obj->efile.bss = NULL;
1164         obj->efile.st_ops_data = NULL;
1165
1166         zfree(&obj->efile.reloc_sects);
1167         obj->efile.nr_reloc_sects = 0;
1168         zclose(obj->efile.fd);
1169         obj->efile.obj_buf = NULL;
1170         obj->efile.obj_buf_sz = 0;
1171 }
1172
1173 static int bpf_object__elf_init(struct bpf_object *obj)
1174 {
1175         int err = 0;
1176         GElf_Ehdr *ep;
1177
1178         if (obj_elf_valid(obj)) {
1179                 pr_warn("elf: init internal error\n");
1180                 return -LIBBPF_ERRNO__LIBELF;
1181         }
1182
1183         if (obj->efile.obj_buf_sz > 0) {
1184                 /*
1185                  * obj_buf should have been validated by
1186                  * bpf_object__open_buffer().
1187                  */
1188                 obj->efile.elf = elf_memory((char *)obj->efile.obj_buf,
1189                                             obj->efile.obj_buf_sz);
1190         } else {
1191                 obj->efile.fd = open(obj->path, O_RDONLY);
1192                 if (obj->efile.fd < 0) {
1193                         char errmsg[STRERR_BUFSIZE], *cp;
1194
1195                         err = -errno;
1196                         cp = libbpf_strerror_r(err, errmsg, sizeof(errmsg));
1197                         pr_warn("elf: failed to open %s: %s\n", obj->path, cp);
1198                         return err;
1199                 }
1200
1201                 obj->efile.elf = elf_begin(obj->efile.fd, ELF_C_READ_MMAP, NULL);
1202         }
1203
1204         if (!obj->efile.elf) {
1205                 pr_warn("elf: failed to open %s as ELF file: %s\n", obj->path, elf_errmsg(-1));
1206                 err = -LIBBPF_ERRNO__LIBELF;
1207                 goto errout;
1208         }
1209
1210         if (!gelf_getehdr(obj->efile.elf, &obj->efile.ehdr)) {
1211                 pr_warn("elf: failed to get ELF header from %s: %s\n", obj->path, elf_errmsg(-1));
1212                 err = -LIBBPF_ERRNO__FORMAT;
1213                 goto errout;
1214         }
1215         ep = &obj->efile.ehdr;
1216
1217         if (elf_getshdrstrndx(obj->efile.elf, &obj->efile.shstrndx)) {
1218                 pr_warn("elf: failed to get section names section index for %s: %s\n",
1219                         obj->path, elf_errmsg(-1));
1220                 err = -LIBBPF_ERRNO__FORMAT;
1221                 goto errout;
1222         }
1223
1224         /* Elf is corrupted/truncated, avoid calling elf_strptr. */
1225         if (!elf_rawdata(elf_getscn(obj->efile.elf, obj->efile.shstrndx), NULL)) {
1226                 pr_warn("elf: failed to get section names strings from %s: %s\n",
1227                         obj->path, elf_errmsg(-1));
1228                 err = -LIBBPF_ERRNO__FORMAT;
1229                 goto errout;
1230         }
1231
1232         /* Old LLVM set e_machine to EM_NONE */
1233         if (ep->e_type != ET_REL ||
1234             (ep->e_machine && ep->e_machine != EM_BPF)) {
1235                 pr_warn("elf: %s is not a valid eBPF object file\n", obj->path);
1236                 err = -LIBBPF_ERRNO__FORMAT;
1237                 goto errout;
1238         }
1239
1240         return 0;
1241 errout:
1242         bpf_object__elf_finish(obj);
1243         return err;
1244 }
1245
1246 static int bpf_object__check_endianness(struct bpf_object *obj)
1247 {
1248 #if __BYTE_ORDER == __LITTLE_ENDIAN
1249         if (obj->efile.ehdr.e_ident[EI_DATA] == ELFDATA2LSB)
1250                 return 0;
1251 #elif __BYTE_ORDER == __BIG_ENDIAN
1252         if (obj->efile.ehdr.e_ident[EI_DATA] == ELFDATA2MSB)
1253                 return 0;
1254 #else
1255 # error "Unrecognized __BYTE_ORDER__"
1256 #endif
1257         pr_warn("elf: endianness mismatch in %s.\n", obj->path);
1258         return -LIBBPF_ERRNO__ENDIAN;
1259 }
1260
1261 static int
1262 bpf_object__init_license(struct bpf_object *obj, void *data, size_t size)
1263 {
1264         memcpy(obj->license, data, min(size, sizeof(obj->license) - 1));
1265         pr_debug("license of %s is %s\n", obj->path, obj->license);
1266         return 0;
1267 }
1268
1269 static int
1270 bpf_object__init_kversion(struct bpf_object *obj, void *data, size_t size)
1271 {
1272         __u32 kver;
1273
1274         if (size != sizeof(kver)) {
1275                 pr_warn("invalid kver section in %s\n", obj->path);
1276                 return -LIBBPF_ERRNO__FORMAT;
1277         }
1278         memcpy(&kver, data, sizeof(kver));
1279         obj->kern_version = kver;
1280         pr_debug("kernel version of %s is %x\n", obj->path, obj->kern_version);
1281         return 0;
1282 }
1283
1284 static bool bpf_map_type__is_map_in_map(enum bpf_map_type type)
1285 {
1286         if (type == BPF_MAP_TYPE_ARRAY_OF_MAPS ||
1287             type == BPF_MAP_TYPE_HASH_OF_MAPS)
1288                 return true;
1289         return false;
1290 }
1291
1292 int bpf_object__section_size(const struct bpf_object *obj, const char *name,
1293                              __u32 *size)
1294 {
1295         int ret = -ENOENT;
1296
1297         *size = 0;
1298         if (!name) {
1299                 return -EINVAL;
1300         } else if (!strcmp(name, DATA_SEC)) {
1301                 if (obj->efile.data)
1302                         *size = obj->efile.data->d_size;
1303         } else if (!strcmp(name, BSS_SEC)) {
1304                 if (obj->efile.bss)
1305                         *size = obj->efile.bss->d_size;
1306         } else if (!strcmp(name, RODATA_SEC)) {
1307                 if (obj->efile.rodata)
1308                         *size = obj->efile.rodata->d_size;
1309         } else if (!strcmp(name, STRUCT_OPS_SEC)) {
1310                 if (obj->efile.st_ops_data)
1311                         *size = obj->efile.st_ops_data->d_size;
1312         } else {
1313                 Elf_Scn *scn = elf_sec_by_name(obj, name);
1314                 Elf_Data *data = elf_sec_data(obj, scn);
1315
1316                 if (data) {
1317                         ret = 0; /* found it */
1318                         *size = data->d_size;
1319                 }
1320         }
1321
1322         return *size ? 0 : ret;
1323 }
1324
1325 int bpf_object__variable_offset(const struct bpf_object *obj, const char *name,
1326                                 __u32 *off)
1327 {
1328         Elf_Data *symbols = obj->efile.symbols;
1329         const char *sname;
1330         size_t si;
1331
1332         if (!name || !off)
1333                 return -EINVAL;
1334
1335         for (si = 0; si < symbols->d_size / sizeof(GElf_Sym); si++) {
1336                 GElf_Sym sym;
1337
1338                 if (!gelf_getsym(symbols, si, &sym))
1339                         continue;
1340                 if (GELF_ST_BIND(sym.st_info) != STB_GLOBAL ||
1341                     GELF_ST_TYPE(sym.st_info) != STT_OBJECT)
1342                         continue;
1343
1344                 sname = elf_sym_str(obj, sym.st_name);
1345                 if (!sname) {
1346                         pr_warn("failed to get sym name string for var %s\n",
1347                                 name);
1348                         return -EIO;
1349                 }
1350                 if (strcmp(name, sname) == 0) {
1351                         *off = sym.st_value;
1352                         return 0;
1353                 }
1354         }
1355
1356         return -ENOENT;
1357 }
1358
1359 static struct bpf_map *bpf_object__add_map(struct bpf_object *obj)
1360 {
1361         struct bpf_map *new_maps;
1362         size_t new_cap;
1363         int i;
1364
1365         if (obj->nr_maps < obj->maps_cap)
1366                 return &obj->maps[obj->nr_maps++];
1367
1368         new_cap = max((size_t)4, obj->maps_cap * 3 / 2);
1369         new_maps = libbpf_reallocarray(obj->maps, new_cap, sizeof(*obj->maps));
1370         if (!new_maps) {
1371                 pr_warn("alloc maps for object failed\n");
1372                 return ERR_PTR(-ENOMEM);
1373         }
1374
1375         obj->maps_cap = new_cap;
1376         obj->maps = new_maps;
1377
1378         /* zero out new maps */
1379         memset(obj->maps + obj->nr_maps, 0,
1380                (obj->maps_cap - obj->nr_maps) * sizeof(*obj->maps));
1381         /*
1382          * fill all fd with -1 so won't close incorrect fd (fd=0 is stdin)
1383          * when failure (zclose won't close negative fd)).
1384          */
1385         for (i = obj->nr_maps; i < obj->maps_cap; i++) {
1386                 obj->maps[i].fd = -1;
1387                 obj->maps[i].inner_map_fd = -1;
1388         }
1389
1390         return &obj->maps[obj->nr_maps++];
1391 }
1392
1393 static size_t bpf_map_mmap_sz(const struct bpf_map *map)
1394 {
1395         long page_sz = sysconf(_SC_PAGE_SIZE);
1396         size_t map_sz;
1397
1398         map_sz = (size_t)roundup(map->def.value_size, 8) * map->def.max_entries;
1399         map_sz = roundup(map_sz, page_sz);
1400         return map_sz;
1401 }
1402
1403 static char *internal_map_name(struct bpf_object *obj,
1404                                enum libbpf_map_type type)
1405 {
1406         char map_name[BPF_OBJ_NAME_LEN], *p;
1407         const char *sfx = libbpf_type_to_btf_name[type];
1408         int sfx_len = max((size_t)7, strlen(sfx));
1409         int pfx_len = min((size_t)BPF_OBJ_NAME_LEN - sfx_len - 1,
1410                           strlen(obj->name));
1411
1412         snprintf(map_name, sizeof(map_name), "%.*s%.*s", pfx_len, obj->name,
1413                  sfx_len, libbpf_type_to_btf_name[type]);
1414
1415         /* sanitise map name to characters allowed by kernel */
1416         for (p = map_name; *p && p < map_name + sizeof(map_name); p++)
1417                 if (!isalnum(*p) && *p != '_' && *p != '.')
1418                         *p = '_';
1419
1420         return strdup(map_name);
1421 }
1422
1423 static int
1424 bpf_object__init_internal_map(struct bpf_object *obj, enum libbpf_map_type type,
1425                               int sec_idx, void *data, size_t data_sz)
1426 {
1427         struct bpf_map_def *def;
1428         struct bpf_map *map;
1429         int err;
1430
1431         map = bpf_object__add_map(obj);
1432         if (IS_ERR(map))
1433                 return PTR_ERR(map);
1434
1435         map->libbpf_type = type;
1436         map->sec_idx = sec_idx;
1437         map->sec_offset = 0;
1438         map->name = internal_map_name(obj, type);
1439         if (!map->name) {
1440                 pr_warn("failed to alloc map name\n");
1441                 return -ENOMEM;
1442         }
1443
1444         def = &map->def;
1445         def->type = BPF_MAP_TYPE_ARRAY;
1446         def->key_size = sizeof(int);
1447         def->value_size = data_sz;
1448         def->max_entries = 1;
1449         def->map_flags = type == LIBBPF_MAP_RODATA || type == LIBBPF_MAP_KCONFIG
1450                          ? BPF_F_RDONLY_PROG : 0;
1451         def->map_flags |= BPF_F_MMAPABLE;
1452
1453         pr_debug("map '%s' (global data): at sec_idx %d, offset %zu, flags %x.\n",
1454                  map->name, map->sec_idx, map->sec_offset, def->map_flags);
1455
1456         map->mmaped = mmap(NULL, bpf_map_mmap_sz(map), PROT_READ | PROT_WRITE,
1457                            MAP_SHARED | MAP_ANONYMOUS, -1, 0);
1458         if (map->mmaped == MAP_FAILED) {
1459                 err = -errno;
1460                 map->mmaped = NULL;
1461                 pr_warn("failed to alloc map '%s' content buffer: %d\n",
1462                         map->name, err);
1463                 zfree(&map->name);
1464                 return err;
1465         }
1466
1467         if (data)
1468                 memcpy(map->mmaped, data, data_sz);
1469
1470         pr_debug("map %td is \"%s\"\n", map - obj->maps, map->name);
1471         return 0;
1472 }
1473
1474 static int bpf_object__init_global_data_maps(struct bpf_object *obj)
1475 {
1476         int err;
1477
1478         /*
1479          * Populate obj->maps with libbpf internal maps.
1480          */
1481         if (obj->efile.data_shndx >= 0) {
1482                 err = bpf_object__init_internal_map(obj, LIBBPF_MAP_DATA,
1483                                                     obj->efile.data_shndx,
1484                                                     obj->efile.data->d_buf,
1485                                                     obj->efile.data->d_size);
1486                 if (err)
1487                         return err;
1488         }
1489         if (obj->efile.rodata_shndx >= 0) {
1490                 err = bpf_object__init_internal_map(obj, LIBBPF_MAP_RODATA,
1491                                                     obj->efile.rodata_shndx,
1492                                                     obj->efile.rodata->d_buf,
1493                                                     obj->efile.rodata->d_size);
1494                 if (err)
1495                         return err;
1496
1497                 obj->rodata_map_idx = obj->nr_maps - 1;
1498         }
1499         if (obj->efile.bss_shndx >= 0) {
1500                 err = bpf_object__init_internal_map(obj, LIBBPF_MAP_BSS,
1501                                                     obj->efile.bss_shndx,
1502                                                     NULL,
1503                                                     obj->efile.bss->d_size);
1504                 if (err)
1505                         return err;
1506         }
1507         return 0;
1508 }
1509
1510
1511 static struct extern_desc *find_extern_by_name(const struct bpf_object *obj,
1512                                                const void *name)
1513 {
1514         int i;
1515
1516         for (i = 0; i < obj->nr_extern; i++) {
1517                 if (strcmp(obj->externs[i].name, name) == 0)
1518                         return &obj->externs[i];
1519         }
1520         return NULL;
1521 }
1522
1523 static int set_kcfg_value_tri(struct extern_desc *ext, void *ext_val,
1524                               char value)
1525 {
1526         switch (ext->kcfg.type) {
1527         case KCFG_BOOL:
1528                 if (value == 'm') {
1529                         pr_warn("extern (kcfg) %s=%c should be tristate or char\n",
1530                                 ext->name, value);
1531                         return -EINVAL;
1532                 }
1533                 *(bool *)ext_val = value == 'y' ? true : false;
1534                 break;
1535         case KCFG_TRISTATE:
1536                 if (value == 'y')
1537                         *(enum libbpf_tristate *)ext_val = TRI_YES;
1538                 else if (value == 'm')
1539                         *(enum libbpf_tristate *)ext_val = TRI_MODULE;
1540                 else /* value == 'n' */
1541                         *(enum libbpf_tristate *)ext_val = TRI_NO;
1542                 break;
1543         case KCFG_CHAR:
1544                 *(char *)ext_val = value;
1545                 break;
1546         case KCFG_UNKNOWN:
1547         case KCFG_INT:
1548         case KCFG_CHAR_ARR:
1549         default:
1550                 pr_warn("extern (kcfg) %s=%c should be bool, tristate, or char\n",
1551                         ext->name, value);
1552                 return -EINVAL;
1553         }
1554         ext->is_set = true;
1555         return 0;
1556 }
1557
1558 static int set_kcfg_value_str(struct extern_desc *ext, char *ext_val,
1559                               const char *value)
1560 {
1561         size_t len;
1562
1563         if (ext->kcfg.type != KCFG_CHAR_ARR) {
1564                 pr_warn("extern (kcfg) %s=%s should be char array\n", ext->name, value);
1565                 return -EINVAL;
1566         }
1567
1568         len = strlen(value);
1569         if (value[len - 1] != '"') {
1570                 pr_warn("extern (kcfg) '%s': invalid string config '%s'\n",
1571                         ext->name, value);
1572                 return -EINVAL;
1573         }
1574
1575         /* strip quotes */
1576         len -= 2;
1577         if (len >= ext->kcfg.sz) {
1578                 pr_warn("extern (kcfg) '%s': long string config %s of (%zu bytes) truncated to %d bytes\n",
1579                         ext->name, value, len, ext->kcfg.sz - 1);
1580                 len = ext->kcfg.sz - 1;
1581         }
1582         memcpy(ext_val, value + 1, len);
1583         ext_val[len] = '\0';
1584         ext->is_set = true;
1585         return 0;
1586 }
1587
1588 static int parse_u64(const char *value, __u64 *res)
1589 {
1590         char *value_end;
1591         int err;
1592
1593         errno = 0;
1594         *res = strtoull(value, &value_end, 0);
1595         if (errno) {
1596                 err = -errno;
1597                 pr_warn("failed to parse '%s' as integer: %d\n", value, err);
1598                 return err;
1599         }
1600         if (*value_end) {
1601                 pr_warn("failed to parse '%s' as integer completely\n", value);
1602                 return -EINVAL;
1603         }
1604         return 0;
1605 }
1606
1607 static bool is_kcfg_value_in_range(const struct extern_desc *ext, __u64 v)
1608 {
1609         int bit_sz = ext->kcfg.sz * 8;
1610
1611         if (ext->kcfg.sz == 8)
1612                 return true;
1613
1614         /* Validate that value stored in u64 fits in integer of `ext->sz`
1615          * bytes size without any loss of information. If the target integer
1616          * is signed, we rely on the following limits of integer type of
1617          * Y bits and subsequent transformation:
1618          *
1619          *     -2^(Y-1) <= X           <= 2^(Y-1) - 1
1620          *            0 <= X + 2^(Y-1) <= 2^Y - 1
1621          *            0 <= X + 2^(Y-1) <  2^Y
1622          *
1623          *  For unsigned target integer, check that all the (64 - Y) bits are
1624          *  zero.
1625          */
1626         if (ext->kcfg.is_signed)
1627                 return v + (1ULL << (bit_sz - 1)) < (1ULL << bit_sz);
1628         else
1629                 return (v >> bit_sz) == 0;
1630 }
1631
1632 static int set_kcfg_value_num(struct extern_desc *ext, void *ext_val,
1633                               __u64 value)
1634 {
1635         if (ext->kcfg.type != KCFG_INT && ext->kcfg.type != KCFG_CHAR) {
1636                 pr_warn("extern (kcfg) %s=%llu should be integer\n",
1637                         ext->name, (unsigned long long)value);
1638                 return -EINVAL;
1639         }
1640         if (!is_kcfg_value_in_range(ext, value)) {
1641                 pr_warn("extern (kcfg) %s=%llu value doesn't fit in %d bytes\n",
1642                         ext->name, (unsigned long long)value, ext->kcfg.sz);
1643                 return -ERANGE;
1644         }
1645         switch (ext->kcfg.sz) {
1646                 case 1: *(__u8 *)ext_val = value; break;
1647                 case 2: *(__u16 *)ext_val = value; break;
1648                 case 4: *(__u32 *)ext_val = value; break;
1649                 case 8: *(__u64 *)ext_val = value; break;
1650                 default:
1651                         return -EINVAL;
1652         }
1653         ext->is_set = true;
1654         return 0;
1655 }
1656
1657 static int bpf_object__process_kconfig_line(struct bpf_object *obj,
1658                                             char *buf, void *data)
1659 {
1660         struct extern_desc *ext;
1661         char *sep, *value;
1662         int len, err = 0;
1663         void *ext_val;
1664         __u64 num;
1665
1666         if (strncmp(buf, "CONFIG_", 7))
1667                 return 0;
1668
1669         sep = strchr(buf, '=');
1670         if (!sep) {
1671                 pr_warn("failed to parse '%s': no separator\n", buf);
1672                 return -EINVAL;
1673         }
1674
1675         /* Trim ending '\n' */
1676         len = strlen(buf);
1677         if (buf[len - 1] == '\n')
1678                 buf[len - 1] = '\0';
1679         /* Split on '=' and ensure that a value is present. */
1680         *sep = '\0';
1681         if (!sep[1]) {
1682                 *sep = '=';
1683                 pr_warn("failed to parse '%s': no value\n", buf);
1684                 return -EINVAL;
1685         }
1686
1687         ext = find_extern_by_name(obj, buf);
1688         if (!ext || ext->is_set)
1689                 return 0;
1690
1691         ext_val = data + ext->kcfg.data_off;
1692         value = sep + 1;
1693
1694         switch (*value) {
1695         case 'y': case 'n': case 'm':
1696                 err = set_kcfg_value_tri(ext, ext_val, *value);
1697                 break;
1698         case '"':
1699                 err = set_kcfg_value_str(ext, ext_val, value);
1700                 break;
1701         default:
1702                 /* assume integer */
1703                 err = parse_u64(value, &num);
1704                 if (err) {
1705                         pr_warn("extern (kcfg) %s=%s should be integer\n",
1706                                 ext->name, value);
1707                         return err;
1708                 }
1709                 err = set_kcfg_value_num(ext, ext_val, num);
1710                 break;
1711         }
1712         if (err)
1713                 return err;
1714         pr_debug("extern (kcfg) %s=%s\n", ext->name, value);
1715         return 0;
1716 }
1717
1718 static int bpf_object__read_kconfig_file(struct bpf_object *obj, void *data)
1719 {
1720         char buf[PATH_MAX];
1721         struct utsname uts;
1722         int len, err = 0;
1723         gzFile file;
1724
1725         uname(&uts);
1726         len = snprintf(buf, PATH_MAX, "/boot/config-%s", uts.release);
1727         if (len < 0)
1728                 return -EINVAL;
1729         else if (len >= PATH_MAX)
1730                 return -ENAMETOOLONG;
1731
1732         /* gzopen also accepts uncompressed files. */
1733         file = gzopen(buf, "r");
1734         if (!file)
1735                 file = gzopen("/proc/config.gz", "r");
1736
1737         if (!file) {
1738                 pr_warn("failed to open system Kconfig\n");
1739                 return -ENOENT;
1740         }
1741
1742         while (gzgets(file, buf, sizeof(buf))) {
1743                 err = bpf_object__process_kconfig_line(obj, buf, data);
1744                 if (err) {
1745                         pr_warn("error parsing system Kconfig line '%s': %d\n",
1746                                 buf, err);
1747                         goto out;
1748                 }
1749         }
1750
1751 out:
1752         gzclose(file);
1753         return err;
1754 }
1755
1756 static int bpf_object__read_kconfig_mem(struct bpf_object *obj,
1757                                         const char *config, void *data)
1758 {
1759         char buf[PATH_MAX];
1760         int err = 0;
1761         FILE *file;
1762
1763         file = fmemopen((void *)config, strlen(config), "r");
1764         if (!file) {
1765                 err = -errno;
1766                 pr_warn("failed to open in-memory Kconfig: %d\n", err);
1767                 return err;
1768         }
1769
1770         while (fgets(buf, sizeof(buf), file)) {
1771                 err = bpf_object__process_kconfig_line(obj, buf, data);
1772                 if (err) {
1773                         pr_warn("error parsing in-memory Kconfig line '%s': %d\n",
1774                                 buf, err);
1775                         break;
1776                 }
1777         }
1778
1779         fclose(file);
1780         return err;
1781 }
1782
1783 static int bpf_object__init_kconfig_map(struct bpf_object *obj)
1784 {
1785         struct extern_desc *last_ext = NULL, *ext;
1786         size_t map_sz;
1787         int i, err;
1788
1789         for (i = 0; i < obj->nr_extern; i++) {
1790                 ext = &obj->externs[i];
1791                 if (ext->type == EXT_KCFG)
1792                         last_ext = ext;
1793         }
1794
1795         if (!last_ext)
1796                 return 0;
1797
1798         map_sz = last_ext->kcfg.data_off + last_ext->kcfg.sz;
1799         err = bpf_object__init_internal_map(obj, LIBBPF_MAP_KCONFIG,
1800                                             obj->efile.symbols_shndx,
1801                                             NULL, map_sz);
1802         if (err)
1803                 return err;
1804
1805         obj->kconfig_map_idx = obj->nr_maps - 1;
1806
1807         return 0;
1808 }
1809
1810 static int bpf_object__init_user_maps(struct bpf_object *obj, bool strict)
1811 {
1812         Elf_Data *symbols = obj->efile.symbols;
1813         int i, map_def_sz = 0, nr_maps = 0, nr_syms;
1814         Elf_Data *data = NULL;
1815         Elf_Scn *scn;
1816
1817         if (obj->efile.maps_shndx < 0)
1818                 return 0;
1819
1820         if (!symbols)
1821                 return -EINVAL;
1822
1823         scn = elf_sec_by_idx(obj, obj->efile.maps_shndx);
1824         data = elf_sec_data(obj, scn);
1825         if (!scn || !data) {
1826                 pr_warn("elf: failed to get legacy map definitions for %s\n",
1827                         obj->path);
1828                 return -EINVAL;
1829         }
1830
1831         /*
1832          * Count number of maps. Each map has a name.
1833          * Array of maps is not supported: only the first element is
1834          * considered.
1835          *
1836          * TODO: Detect array of map and report error.
1837          */
1838         nr_syms = symbols->d_size / sizeof(GElf_Sym);
1839         for (i = 0; i < nr_syms; i++) {
1840                 GElf_Sym sym;
1841
1842                 if (!gelf_getsym(symbols, i, &sym))
1843                         continue;
1844                 if (sym.st_shndx != obj->efile.maps_shndx)
1845                         continue;
1846                 nr_maps++;
1847         }
1848         /* Assume equally sized map definitions */
1849         pr_debug("elf: found %d legacy map definitions (%zd bytes) in %s\n",
1850                  nr_maps, data->d_size, obj->path);
1851
1852         if (!data->d_size || nr_maps == 0 || (data->d_size % nr_maps) != 0) {
1853                 pr_warn("elf: unable to determine legacy map definition size in %s\n",
1854                         obj->path);
1855                 return -EINVAL;
1856         }
1857         map_def_sz = data->d_size / nr_maps;
1858
1859         /* Fill obj->maps using data in "maps" section.  */
1860         for (i = 0; i < nr_syms; i++) {
1861                 GElf_Sym sym;
1862                 const char *map_name;
1863                 struct bpf_map_def *def;
1864                 struct bpf_map *map;
1865
1866                 if (!gelf_getsym(symbols, i, &sym))
1867                         continue;
1868                 if (sym.st_shndx != obj->efile.maps_shndx)
1869                         continue;
1870
1871                 map = bpf_object__add_map(obj);
1872                 if (IS_ERR(map))
1873                         return PTR_ERR(map);
1874
1875                 map_name = elf_sym_str(obj, sym.st_name);
1876                 if (!map_name) {
1877                         pr_warn("failed to get map #%d name sym string for obj %s\n",
1878                                 i, obj->path);
1879                         return -LIBBPF_ERRNO__FORMAT;
1880                 }
1881
1882                 if (GELF_ST_TYPE(sym.st_info) == STT_SECTION
1883                     || GELF_ST_BIND(sym.st_info) == STB_LOCAL) {
1884                         pr_warn("map '%s' (legacy): static maps are not supported\n", map_name);
1885                         return -ENOTSUP;
1886                 }
1887
1888                 map->libbpf_type = LIBBPF_MAP_UNSPEC;
1889                 map->sec_idx = sym.st_shndx;
1890                 map->sec_offset = sym.st_value;
1891                 pr_debug("map '%s' (legacy): at sec_idx %d, offset %zu.\n",
1892                          map_name, map->sec_idx, map->sec_offset);
1893                 if (sym.st_value + map_def_sz > data->d_size) {
1894                         pr_warn("corrupted maps section in %s: last map \"%s\" too small\n",
1895                                 obj->path, map_name);
1896                         return -EINVAL;
1897                 }
1898
1899                 map->name = strdup(map_name);
1900                 if (!map->name) {
1901                         pr_warn("failed to alloc map name\n");
1902                         return -ENOMEM;
1903                 }
1904                 pr_debug("map %d is \"%s\"\n", i, map->name);
1905                 def = (struct bpf_map_def *)(data->d_buf + sym.st_value);
1906                 /*
1907                  * If the definition of the map in the object file fits in
1908                  * bpf_map_def, copy it.  Any extra fields in our version
1909                  * of bpf_map_def will default to zero as a result of the
1910                  * calloc above.
1911                  */
1912                 if (map_def_sz <= sizeof(struct bpf_map_def)) {
1913                         memcpy(&map->def, def, map_def_sz);
1914                 } else {
1915                         /*
1916                          * Here the map structure being read is bigger than what
1917                          * we expect, truncate if the excess bits are all zero.
1918                          * If they are not zero, reject this map as
1919                          * incompatible.
1920                          */
1921                         char *b;
1922
1923                         for (b = ((char *)def) + sizeof(struct bpf_map_def);
1924                              b < ((char *)def) + map_def_sz; b++) {
1925                                 if (*b != 0) {
1926                                         pr_warn("maps section in %s: \"%s\" has unrecognized, non-zero options\n",
1927                                                 obj->path, map_name);
1928                                         if (strict)
1929                                                 return -EINVAL;
1930                                 }
1931                         }
1932                         memcpy(&map->def, def, sizeof(struct bpf_map_def));
1933                 }
1934         }
1935         return 0;
1936 }
1937
1938 const struct btf_type *
1939 skip_mods_and_typedefs(const struct btf *btf, __u32 id, __u32 *res_id)
1940 {
1941         const struct btf_type *t = btf__type_by_id(btf, id);
1942
1943         if (res_id)
1944                 *res_id = id;
1945
1946         while (btf_is_mod(t) || btf_is_typedef(t)) {
1947                 if (res_id)
1948                         *res_id = t->type;
1949                 t = btf__type_by_id(btf, t->type);
1950         }
1951
1952         return t;
1953 }
1954
1955 static const struct btf_type *
1956 resolve_func_ptr(const struct btf *btf, __u32 id, __u32 *res_id)
1957 {
1958         const struct btf_type *t;
1959
1960         t = skip_mods_and_typedefs(btf, id, NULL);
1961         if (!btf_is_ptr(t))
1962                 return NULL;
1963
1964         t = skip_mods_and_typedefs(btf, t->type, res_id);
1965
1966         return btf_is_func_proto(t) ? t : NULL;
1967 }
1968
1969 static const char *__btf_kind_str(__u16 kind)
1970 {
1971         switch (kind) {
1972         case BTF_KIND_UNKN: return "void";
1973         case BTF_KIND_INT: return "int";
1974         case BTF_KIND_PTR: return "ptr";
1975         case BTF_KIND_ARRAY: return "array";
1976         case BTF_KIND_STRUCT: return "struct";
1977         case BTF_KIND_UNION: return "union";
1978         case BTF_KIND_ENUM: return "enum";
1979         case BTF_KIND_FWD: return "fwd";
1980         case BTF_KIND_TYPEDEF: return "typedef";
1981         case BTF_KIND_VOLATILE: return "volatile";
1982         case BTF_KIND_CONST: return "const";
1983         case BTF_KIND_RESTRICT: return "restrict";
1984         case BTF_KIND_FUNC: return "func";
1985         case BTF_KIND_FUNC_PROTO: return "func_proto";
1986         case BTF_KIND_VAR: return "var";
1987         case BTF_KIND_DATASEC: return "datasec";
1988         case BTF_KIND_FLOAT: return "float";
1989         default: return "unknown";
1990         }
1991 }
1992
1993 const char *btf_kind_str(const struct btf_type *t)
1994 {
1995         return __btf_kind_str(btf_kind(t));
1996 }
1997
1998 /*
1999  * Fetch integer attribute of BTF map definition. Such attributes are
2000  * represented using a pointer to an array, in which dimensionality of array
2001  * encodes specified integer value. E.g., int (*type)[BPF_MAP_TYPE_ARRAY];
2002  * encodes `type => BPF_MAP_TYPE_ARRAY` key/value pair completely using BTF
2003  * type definition, while using only sizeof(void *) space in ELF data section.
2004  */
2005 static bool get_map_field_int(const char *map_name, const struct btf *btf,
2006                               const struct btf_member *m, __u32 *res)
2007 {
2008         const struct btf_type *t = skip_mods_and_typedefs(btf, m->type, NULL);
2009         const char *name = btf__name_by_offset(btf, m->name_off);
2010         const struct btf_array *arr_info;
2011         const struct btf_type *arr_t;
2012
2013         if (!btf_is_ptr(t)) {
2014                 pr_warn("map '%s': attr '%s': expected PTR, got %s.\n",
2015                         map_name, name, btf_kind_str(t));
2016                 return false;
2017         }
2018
2019         arr_t = btf__type_by_id(btf, t->type);
2020         if (!arr_t) {
2021                 pr_warn("map '%s': attr '%s': type [%u] not found.\n",
2022                         map_name, name, t->type);
2023                 return false;
2024         }
2025         if (!btf_is_array(arr_t)) {
2026                 pr_warn("map '%s': attr '%s': expected ARRAY, got %s.\n",
2027                         map_name, name, btf_kind_str(arr_t));
2028                 return false;
2029         }
2030         arr_info = btf_array(arr_t);
2031         *res = arr_info->nelems;
2032         return true;
2033 }
2034
2035 static int build_map_pin_path(struct bpf_map *map, const char *path)
2036 {
2037         char buf[PATH_MAX];
2038         int len;
2039
2040         if (!path)
2041                 path = "/sys/fs/bpf";
2042
2043         len = snprintf(buf, PATH_MAX, "%s/%s", path, bpf_map__name(map));
2044         if (len < 0)
2045                 return -EINVAL;
2046         else if (len >= PATH_MAX)
2047                 return -ENAMETOOLONG;
2048
2049         return bpf_map__set_pin_path(map, buf);
2050 }
2051
2052 int parse_btf_map_def(const char *map_name, struct btf *btf,
2053                       const struct btf_type *def_t, bool strict,
2054                       struct btf_map_def *map_def, struct btf_map_def *inner_def)
2055 {
2056         const struct btf_type *t;
2057         const struct btf_member *m;
2058         bool is_inner = inner_def == NULL;
2059         int vlen, i;
2060
2061         vlen = btf_vlen(def_t);
2062         m = btf_members(def_t);
2063         for (i = 0; i < vlen; i++, m++) {
2064                 const char *name = btf__name_by_offset(btf, m->name_off);
2065
2066                 if (!name) {
2067                         pr_warn("map '%s': invalid field #%d.\n", map_name, i);
2068                         return -EINVAL;
2069                 }
2070                 if (strcmp(name, "type") == 0) {
2071                         if (!get_map_field_int(map_name, btf, m, &map_def->map_type))
2072                                 return -EINVAL;
2073                         map_def->parts |= MAP_DEF_MAP_TYPE;
2074                 } else if (strcmp(name, "max_entries") == 0) {
2075                         if (!get_map_field_int(map_name, btf, m, &map_def->max_entries))
2076                                 return -EINVAL;
2077                         map_def->parts |= MAP_DEF_MAX_ENTRIES;
2078                 } else if (strcmp(name, "map_flags") == 0) {
2079                         if (!get_map_field_int(map_name, btf, m, &map_def->map_flags))
2080                                 return -EINVAL;
2081                         map_def->parts |= MAP_DEF_MAP_FLAGS;
2082                 } else if (strcmp(name, "numa_node") == 0) {
2083                         if (!get_map_field_int(map_name, btf, m, &map_def->numa_node))
2084                                 return -EINVAL;
2085                         map_def->parts |= MAP_DEF_NUMA_NODE;
2086                 } else if (strcmp(name, "key_size") == 0) {
2087                         __u32 sz;
2088
2089                         if (!get_map_field_int(map_name, btf, m, &sz))
2090                                 return -EINVAL;
2091                         if (map_def->key_size && map_def->key_size != sz) {
2092                                 pr_warn("map '%s': conflicting key size %u != %u.\n",
2093                                         map_name, map_def->key_size, sz);
2094                                 return -EINVAL;
2095                         }
2096                         map_def->key_size = sz;
2097                         map_def->parts |= MAP_DEF_KEY_SIZE;
2098                 } else if (strcmp(name, "key") == 0) {
2099                         __s64 sz;
2100
2101                         t = btf__type_by_id(btf, m->type);
2102                         if (!t) {
2103                                 pr_warn("map '%s': key type [%d] not found.\n",
2104                                         map_name, m->type);
2105                                 return -EINVAL;
2106                         }
2107                         if (!btf_is_ptr(t)) {
2108                                 pr_warn("map '%s': key spec is not PTR: %s.\n",
2109                                         map_name, btf_kind_str(t));
2110                                 return -EINVAL;
2111                         }
2112                         sz = btf__resolve_size(btf, t->type);
2113                         if (sz < 0) {
2114                                 pr_warn("map '%s': can't determine key size for type [%u]: %zd.\n",
2115                                         map_name, t->type, (ssize_t)sz);
2116                                 return sz;
2117                         }
2118                         if (map_def->key_size && map_def->key_size != sz) {
2119                                 pr_warn("map '%s': conflicting key size %u != %zd.\n",
2120                                         map_name, map_def->key_size, (ssize_t)sz);
2121                                 return -EINVAL;
2122                         }
2123                         map_def->key_size = sz;
2124                         map_def->key_type_id = t->type;
2125                         map_def->parts |= MAP_DEF_KEY_SIZE | MAP_DEF_KEY_TYPE;
2126                 } else if (strcmp(name, "value_size") == 0) {
2127                         __u32 sz;
2128
2129                         if (!get_map_field_int(map_name, btf, m, &sz))
2130                                 return -EINVAL;
2131                         if (map_def->value_size && map_def->value_size != sz) {
2132                                 pr_warn("map '%s': conflicting value size %u != %u.\n",
2133                                         map_name, map_def->value_size, sz);
2134                                 return -EINVAL;
2135                         }
2136                         map_def->value_size = sz;
2137                         map_def->parts |= MAP_DEF_VALUE_SIZE;
2138                 } else if (strcmp(name, "value") == 0) {
2139                         __s64 sz;
2140
2141                         t = btf__type_by_id(btf, m->type);
2142                         if (!t) {
2143                                 pr_warn("map '%s': value type [%d] not found.\n",
2144                                         map_name, m->type);
2145                                 return -EINVAL;
2146                         }
2147                         if (!btf_is_ptr(t)) {
2148                                 pr_warn("map '%s': value spec is not PTR: %s.\n",
2149                                         map_name, btf_kind_str(t));
2150                                 return -EINVAL;
2151                         }
2152                         sz = btf__resolve_size(btf, t->type);
2153                         if (sz < 0) {
2154                                 pr_warn("map '%s': can't determine value size for type [%u]: %zd.\n",
2155                                         map_name, t->type, (ssize_t)sz);
2156                                 return sz;
2157                         }
2158                         if (map_def->value_size && map_def->value_size != sz) {
2159                                 pr_warn("map '%s': conflicting value size %u != %zd.\n",
2160                                         map_name, map_def->value_size, (ssize_t)sz);
2161                                 return -EINVAL;
2162                         }
2163                         map_def->value_size = sz;
2164                         map_def->value_type_id = t->type;
2165                         map_def->parts |= MAP_DEF_VALUE_SIZE | MAP_DEF_VALUE_TYPE;
2166                 }
2167                 else if (strcmp(name, "values") == 0) {
2168                         char inner_map_name[128];
2169                         int err;
2170
2171                         if (is_inner) {
2172                                 pr_warn("map '%s': multi-level inner maps not supported.\n",
2173                                         map_name);
2174                                 return -ENOTSUP;
2175                         }
2176                         if (i != vlen - 1) {
2177                                 pr_warn("map '%s': '%s' member should be last.\n",
2178                                         map_name, name);
2179                                 return -EINVAL;
2180                         }
2181                         if (!bpf_map_type__is_map_in_map(map_def->map_type)) {
2182                                 pr_warn("map '%s': should be map-in-map.\n",
2183                                         map_name);
2184                                 return -ENOTSUP;
2185                         }
2186                         if (map_def->value_size && map_def->value_size != 4) {
2187                                 pr_warn("map '%s': conflicting value size %u != 4.\n",
2188                                         map_name, map_def->value_size);
2189                                 return -EINVAL;
2190                         }
2191                         map_def->value_size = 4;
2192                         t = btf__type_by_id(btf, m->type);
2193                         if (!t) {
2194                                 pr_warn("map '%s': map-in-map inner type [%d] not found.\n",
2195                                         map_name, m->type);
2196                                 return -EINVAL;
2197                         }
2198                         if (!btf_is_array(t) || btf_array(t)->nelems) {
2199                                 pr_warn("map '%s': map-in-map inner spec is not a zero-sized array.\n",
2200                                         map_name);
2201                                 return -EINVAL;
2202                         }
2203                         t = skip_mods_and_typedefs(btf, btf_array(t)->type, NULL);
2204                         if (!btf_is_ptr(t)) {
2205                                 pr_warn("map '%s': map-in-map inner def is of unexpected kind %s.\n",
2206                                         map_name, btf_kind_str(t));
2207                                 return -EINVAL;
2208                         }
2209                         t = skip_mods_and_typedefs(btf, t->type, NULL);
2210                         if (!btf_is_struct(t)) {
2211                                 pr_warn("map '%s': map-in-map inner def is of unexpected kind %s.\n",
2212                                         map_name, btf_kind_str(t));
2213                                 return -EINVAL;
2214                         }
2215
2216                         snprintf(inner_map_name, sizeof(inner_map_name), "%s.inner", map_name);
2217                         err = parse_btf_map_def(inner_map_name, btf, t, strict, inner_def, NULL);
2218                         if (err)
2219                                 return err;
2220
2221                         map_def->parts |= MAP_DEF_INNER_MAP;
2222                 } else if (strcmp(name, "pinning") == 0) {
2223                         __u32 val;
2224
2225                         if (is_inner) {
2226                                 pr_warn("map '%s': inner def can't be pinned.\n", map_name);
2227                                 return -EINVAL;
2228                         }
2229                         if (!get_map_field_int(map_name, btf, m, &val))
2230                                 return -EINVAL;
2231                         if (val != LIBBPF_PIN_NONE && val != LIBBPF_PIN_BY_NAME) {
2232                                 pr_warn("map '%s': invalid pinning value %u.\n",
2233                                         map_name, val);
2234                                 return -EINVAL;
2235                         }
2236                         map_def->pinning = val;
2237                         map_def->parts |= MAP_DEF_PINNING;
2238                 } else {
2239                         if (strict) {
2240                                 pr_warn("map '%s': unknown field '%s'.\n", map_name, name);
2241                                 return -ENOTSUP;
2242                         }
2243                         pr_debug("map '%s': ignoring unknown field '%s'.\n", map_name, name);
2244                 }
2245         }
2246
2247         if (map_def->map_type == BPF_MAP_TYPE_UNSPEC) {
2248                 pr_warn("map '%s': map type isn't specified.\n", map_name);
2249                 return -EINVAL;
2250         }
2251
2252         return 0;
2253 }
2254
2255 static void fill_map_from_def(struct bpf_map *map, const struct btf_map_def *def)
2256 {
2257         map->def.type = def->map_type;
2258         map->def.key_size = def->key_size;
2259         map->def.value_size = def->value_size;
2260         map->def.max_entries = def->max_entries;
2261         map->def.map_flags = def->map_flags;
2262
2263         map->numa_node = def->numa_node;
2264         map->btf_key_type_id = def->key_type_id;
2265         map->btf_value_type_id = def->value_type_id;
2266
2267         if (def->parts & MAP_DEF_MAP_TYPE)
2268                 pr_debug("map '%s': found type = %u.\n", map->name, def->map_type);
2269
2270         if (def->parts & MAP_DEF_KEY_TYPE)
2271                 pr_debug("map '%s': found key [%u], sz = %u.\n",
2272                          map->name, def->key_type_id, def->key_size);
2273         else if (def->parts & MAP_DEF_KEY_SIZE)
2274                 pr_debug("map '%s': found key_size = %u.\n", map->name, def->key_size);
2275
2276         if (def->parts & MAP_DEF_VALUE_TYPE)
2277                 pr_debug("map '%s': found value [%u], sz = %u.\n",
2278                          map->name, def->value_type_id, def->value_size);
2279         else if (def->parts & MAP_DEF_VALUE_SIZE)
2280                 pr_debug("map '%s': found value_size = %u.\n", map->name, def->value_size);
2281
2282         if (def->parts & MAP_DEF_MAX_ENTRIES)
2283                 pr_debug("map '%s': found max_entries = %u.\n", map->name, def->max_entries);
2284         if (def->parts & MAP_DEF_MAP_FLAGS)
2285                 pr_debug("map '%s': found map_flags = %u.\n", map->name, def->map_flags);
2286         if (def->parts & MAP_DEF_PINNING)
2287                 pr_debug("map '%s': found pinning = %u.\n", map->name, def->pinning);
2288         if (def->parts & MAP_DEF_NUMA_NODE)
2289                 pr_debug("map '%s': found numa_node = %u.\n", map->name, def->numa_node);
2290
2291         if (def->parts & MAP_DEF_INNER_MAP)
2292                 pr_debug("map '%s': found inner map definition.\n", map->name);
2293 }
2294
2295 static const char *btf_var_linkage_str(__u32 linkage)
2296 {
2297         switch (linkage) {
2298         case BTF_VAR_STATIC: return "static";
2299         case BTF_VAR_GLOBAL_ALLOCATED: return "global";
2300         case BTF_VAR_GLOBAL_EXTERN: return "extern";
2301         default: return "unknown";
2302         }
2303 }
2304
2305 static int bpf_object__init_user_btf_map(struct bpf_object *obj,
2306                                          const struct btf_type *sec,
2307                                          int var_idx, int sec_idx,
2308                                          const Elf_Data *data, bool strict,
2309                                          const char *pin_root_path)
2310 {
2311         struct btf_map_def map_def = {}, inner_def = {};
2312         const struct btf_type *var, *def;
2313         const struct btf_var_secinfo *vi;
2314         const struct btf_var *var_extra;
2315         const char *map_name;
2316         struct bpf_map *map;
2317         int err;
2318
2319         vi = btf_var_secinfos(sec) + var_idx;
2320         var = btf__type_by_id(obj->btf, vi->type);
2321         var_extra = btf_var(var);
2322         map_name = btf__name_by_offset(obj->btf, var->name_off);
2323
2324         if (map_name == NULL || map_name[0] == '\0') {
2325                 pr_warn("map #%d: empty name.\n", var_idx);
2326                 return -EINVAL;
2327         }
2328         if ((__u64)vi->offset + vi->size > data->d_size) {
2329                 pr_warn("map '%s' BTF data is corrupted.\n", map_name);
2330                 return -EINVAL;
2331         }
2332         if (!btf_is_var(var)) {
2333                 pr_warn("map '%s': unexpected var kind %s.\n",
2334                         map_name, btf_kind_str(var));
2335                 return -EINVAL;
2336         }
2337         if (var_extra->linkage != BTF_VAR_GLOBAL_ALLOCATED) {
2338                 pr_warn("map '%s': unsupported map linkage %s.\n",
2339                         map_name, btf_var_linkage_str(var_extra->linkage));
2340                 return -EOPNOTSUPP;
2341         }
2342
2343         def = skip_mods_and_typedefs(obj->btf, var->type, NULL);
2344         if (!btf_is_struct(def)) {
2345                 pr_warn("map '%s': unexpected def kind %s.\n",
2346                         map_name, btf_kind_str(var));
2347                 return -EINVAL;
2348         }
2349         if (def->size > vi->size) {
2350                 pr_warn("map '%s': invalid def size.\n", map_name);
2351                 return -EINVAL;
2352         }
2353
2354         map = bpf_object__add_map(obj);
2355         if (IS_ERR(map))
2356                 return PTR_ERR(map);
2357         map->name = strdup(map_name);
2358         if (!map->name) {
2359                 pr_warn("map '%s': failed to alloc map name.\n", map_name);
2360                 return -ENOMEM;
2361         }
2362         map->libbpf_type = LIBBPF_MAP_UNSPEC;
2363         map->def.type = BPF_MAP_TYPE_UNSPEC;
2364         map->sec_idx = sec_idx;
2365         map->sec_offset = vi->offset;
2366         map->btf_var_idx = var_idx;
2367         pr_debug("map '%s': at sec_idx %d, offset %zu.\n",
2368                  map_name, map->sec_idx, map->sec_offset);
2369
2370         err = parse_btf_map_def(map->name, obj->btf, def, strict, &map_def, &inner_def);
2371         if (err)
2372                 return err;
2373
2374         fill_map_from_def(map, &map_def);
2375
2376         if (map_def.pinning == LIBBPF_PIN_BY_NAME) {
2377                 err = build_map_pin_path(map, pin_root_path);
2378                 if (err) {
2379                         pr_warn("map '%s': couldn't build pin path.\n", map->name);
2380                         return err;
2381                 }
2382         }
2383
2384         if (map_def.parts & MAP_DEF_INNER_MAP) {
2385                 map->inner_map = calloc(1, sizeof(*map->inner_map));
2386                 if (!map->inner_map)
2387                         return -ENOMEM;
2388                 map->inner_map->fd = -1;
2389                 map->inner_map->sec_idx = sec_idx;
2390                 map->inner_map->name = malloc(strlen(map_name) + sizeof(".inner") + 1);
2391                 if (!map->inner_map->name)
2392                         return -ENOMEM;
2393                 sprintf(map->inner_map->name, "%s.inner", map_name);
2394
2395                 fill_map_from_def(map->inner_map, &inner_def);
2396         }
2397
2398         return 0;
2399 }
2400
2401 static int bpf_object__init_user_btf_maps(struct bpf_object *obj, bool strict,
2402                                           const char *pin_root_path)
2403 {
2404         const struct btf_type *sec = NULL;
2405         int nr_types, i, vlen, err;
2406         const struct btf_type *t;
2407         const char *name;
2408         Elf_Data *data;
2409         Elf_Scn *scn;
2410
2411         if (obj->efile.btf_maps_shndx < 0)
2412                 return 0;
2413
2414         scn = elf_sec_by_idx(obj, obj->efile.btf_maps_shndx);
2415         data = elf_sec_data(obj, scn);
2416         if (!scn || !data) {
2417                 pr_warn("elf: failed to get %s map definitions for %s\n",
2418                         MAPS_ELF_SEC, obj->path);
2419                 return -EINVAL;
2420         }
2421
2422         nr_types = btf__get_nr_types(obj->btf);
2423         for (i = 1; i <= nr_types; i++) {
2424                 t = btf__type_by_id(obj->btf, i);
2425                 if (!btf_is_datasec(t))
2426                         continue;
2427                 name = btf__name_by_offset(obj->btf, t->name_off);
2428                 if (strcmp(name, MAPS_ELF_SEC) == 0) {
2429                         sec = t;
2430                         obj->efile.btf_maps_sec_btf_id = i;
2431                         break;
2432                 }
2433         }
2434
2435         if (!sec) {
2436                 pr_warn("DATASEC '%s' not found.\n", MAPS_ELF_SEC);
2437                 return -ENOENT;
2438         }
2439
2440         vlen = btf_vlen(sec);
2441         for (i = 0; i < vlen; i++) {
2442                 err = bpf_object__init_user_btf_map(obj, sec, i,
2443                                                     obj->efile.btf_maps_shndx,
2444                                                     data, strict,
2445                                                     pin_root_path);
2446                 if (err)
2447                         return err;
2448         }
2449
2450         return 0;
2451 }
2452
2453 static int bpf_object__init_maps(struct bpf_object *obj,
2454                                  const struct bpf_object_open_opts *opts)
2455 {
2456         const char *pin_root_path;
2457         bool strict;
2458         int err;
2459
2460         strict = !OPTS_GET(opts, relaxed_maps, false);
2461         pin_root_path = OPTS_GET(opts, pin_root_path, NULL);
2462
2463         err = bpf_object__init_user_maps(obj, strict);
2464         err = err ?: bpf_object__init_user_btf_maps(obj, strict, pin_root_path);
2465         err = err ?: bpf_object__init_global_data_maps(obj);
2466         err = err ?: bpf_object__init_kconfig_map(obj);
2467         err = err ?: bpf_object__init_struct_ops_maps(obj);
2468
2469         return err;
2470 }
2471
2472 static bool section_have_execinstr(struct bpf_object *obj, int idx)
2473 {
2474         GElf_Shdr sh;
2475
2476         if (elf_sec_hdr(obj, elf_sec_by_idx(obj, idx), &sh))
2477                 return false;
2478
2479         return sh.sh_flags & SHF_EXECINSTR;
2480 }
2481
2482 static bool btf_needs_sanitization(struct bpf_object *obj)
2483 {
2484         bool has_func_global = kernel_supports(obj, FEAT_BTF_GLOBAL_FUNC);
2485         bool has_datasec = kernel_supports(obj, FEAT_BTF_DATASEC);
2486         bool has_float = kernel_supports(obj, FEAT_BTF_FLOAT);
2487         bool has_func = kernel_supports(obj, FEAT_BTF_FUNC);
2488
2489         return !has_func || !has_datasec || !has_func_global || !has_float;
2490 }
2491
2492 static void bpf_object__sanitize_btf(struct bpf_object *obj, struct btf *btf)
2493 {
2494         bool has_func_global = kernel_supports(obj, FEAT_BTF_GLOBAL_FUNC);
2495         bool has_datasec = kernel_supports(obj, FEAT_BTF_DATASEC);
2496         bool has_float = kernel_supports(obj, FEAT_BTF_FLOAT);
2497         bool has_func = kernel_supports(obj, FEAT_BTF_FUNC);
2498         struct btf_type *t;
2499         int i, j, vlen;
2500
2501         for (i = 1; i <= btf__get_nr_types(btf); i++) {
2502                 t = (struct btf_type *)btf__type_by_id(btf, i);
2503
2504                 if (!has_datasec && btf_is_var(t)) {
2505                         /* replace VAR with INT */
2506                         t->info = BTF_INFO_ENC(BTF_KIND_INT, 0, 0);
2507                         /*
2508                          * using size = 1 is the safest choice, 4 will be too
2509                          * big and cause kernel BTF validation failure if
2510                          * original variable took less than 4 bytes
2511                          */
2512                         t->size = 1;
2513                         *(int *)(t + 1) = BTF_INT_ENC(0, 0, 8);
2514                 } else if (!has_datasec && btf_is_datasec(t)) {
2515                         /* replace DATASEC with STRUCT */
2516                         const struct btf_var_secinfo *v = btf_var_secinfos(t);
2517                         struct btf_member *m = btf_members(t);
2518                         struct btf_type *vt;
2519                         char *name;
2520
2521                         name = (char *)btf__name_by_offset(btf, t->name_off);
2522                         while (*name) {
2523                                 if (*name == '.')
2524                                         *name = '_';
2525                                 name++;
2526                         }
2527
2528                         vlen = btf_vlen(t);
2529                         t->info = BTF_INFO_ENC(BTF_KIND_STRUCT, 0, vlen);
2530                         for (j = 0; j < vlen; j++, v++, m++) {
2531                                 /* order of field assignments is important */
2532                                 m->offset = v->offset * 8;
2533                                 m->type = v->type;
2534                                 /* preserve variable name as member name */
2535                                 vt = (void *)btf__type_by_id(btf, v->type);
2536                                 m->name_off = vt->name_off;
2537                         }
2538                 } else if (!has_func && btf_is_func_proto(t)) {
2539                         /* replace FUNC_PROTO with ENUM */
2540                         vlen = btf_vlen(t);
2541                         t->info = BTF_INFO_ENC(BTF_KIND_ENUM, 0, vlen);
2542                         t->size = sizeof(__u32); /* kernel enforced */
2543                 } else if (!has_func && btf_is_func(t)) {
2544                         /* replace FUNC with TYPEDEF */
2545                         t->info = BTF_INFO_ENC(BTF_KIND_TYPEDEF, 0, 0);
2546                 } else if (!has_func_global && btf_is_func(t)) {
2547                         /* replace BTF_FUNC_GLOBAL with BTF_FUNC_STATIC */
2548                         t->info = BTF_INFO_ENC(BTF_KIND_FUNC, 0, 0);
2549                 } else if (!has_float && btf_is_float(t)) {
2550                         /* replace FLOAT with an equally-sized empty STRUCT;
2551                          * since C compilers do not accept e.g. "float" as a
2552                          * valid struct name, make it anonymous
2553                          */
2554                         t->name_off = 0;
2555                         t->info = BTF_INFO_ENC(BTF_KIND_STRUCT, 0, 0);
2556                 }
2557         }
2558 }
2559
2560 static bool libbpf_needs_btf(const struct bpf_object *obj)
2561 {
2562         return obj->efile.btf_maps_shndx >= 0 ||
2563                obj->efile.st_ops_shndx >= 0 ||
2564                obj->nr_extern > 0;
2565 }
2566
2567 static bool kernel_needs_btf(const struct bpf_object *obj)
2568 {
2569         return obj->efile.st_ops_shndx >= 0;
2570 }
2571
2572 static int bpf_object__init_btf(struct bpf_object *obj,
2573                                 Elf_Data *btf_data,
2574                                 Elf_Data *btf_ext_data)
2575 {
2576         int err = -ENOENT;
2577
2578         if (btf_data) {
2579                 obj->btf = btf__new(btf_data->d_buf, btf_data->d_size);
2580                 err = libbpf_get_error(obj->btf);
2581                 if (err) {
2582                         obj->btf = NULL;
2583                         pr_warn("Error loading ELF section %s: %d.\n", BTF_ELF_SEC, err);
2584                         goto out;
2585                 }
2586                 /* enforce 8-byte pointers for BPF-targeted BTFs */
2587                 btf__set_pointer_size(obj->btf, 8);
2588         }
2589         if (btf_ext_data) {
2590                 if (!obj->btf) {
2591                         pr_debug("Ignore ELF section %s because its depending ELF section %s is not found.\n",
2592                                  BTF_EXT_ELF_SEC, BTF_ELF_SEC);
2593                         goto out;
2594                 }
2595                 obj->btf_ext = btf_ext__new(btf_ext_data->d_buf, btf_ext_data->d_size);
2596                 err = libbpf_get_error(obj->btf_ext);
2597                 if (err) {
2598                         pr_warn("Error loading ELF section %s: %d. Ignored and continue.\n",
2599                                 BTF_EXT_ELF_SEC, err);
2600                         obj->btf_ext = NULL;
2601                         goto out;
2602                 }
2603         }
2604 out:
2605         if (err && libbpf_needs_btf(obj)) {
2606                 pr_warn("BTF is required, but is missing or corrupted.\n");
2607                 return err;
2608         }
2609         return 0;
2610 }
2611
2612 static int bpf_object__finalize_btf(struct bpf_object *obj)
2613 {
2614         int err;
2615
2616         if (!obj->btf)
2617                 return 0;
2618
2619         err = btf__finalize_data(obj, obj->btf);
2620         if (err) {
2621                 pr_warn("Error finalizing %s: %d.\n", BTF_ELF_SEC, err);
2622                 return err;
2623         }
2624
2625         return 0;
2626 }
2627
2628 static bool prog_needs_vmlinux_btf(struct bpf_program *prog)
2629 {
2630         if (prog->type == BPF_PROG_TYPE_STRUCT_OPS ||
2631             prog->type == BPF_PROG_TYPE_LSM)
2632                 return true;
2633
2634         /* BPF_PROG_TYPE_TRACING programs which do not attach to other programs
2635          * also need vmlinux BTF
2636          */
2637         if (prog->type == BPF_PROG_TYPE_TRACING && !prog->attach_prog_fd)
2638                 return true;
2639
2640         return false;
2641 }
2642
2643 static bool obj_needs_vmlinux_btf(const struct bpf_object *obj)
2644 {
2645         struct bpf_program *prog;
2646         int i;
2647
2648         /* CO-RE relocations need kernel BTF */
2649         if (obj->btf_ext && obj->btf_ext->core_relo_info.len)
2650                 return true;
2651
2652         /* Support for typed ksyms needs kernel BTF */
2653         for (i = 0; i < obj->nr_extern; i++) {
2654                 const struct extern_desc *ext;
2655
2656                 ext = &obj->externs[i];
2657                 if (ext->type == EXT_KSYM && ext->ksym.type_id)
2658                         return true;
2659         }
2660
2661         bpf_object__for_each_program(prog, obj) {
2662                 if (!prog->load)
2663                         continue;
2664                 if (prog_needs_vmlinux_btf(prog))
2665                         return true;
2666         }
2667
2668         return false;
2669 }
2670
2671 static int bpf_object__load_vmlinux_btf(struct bpf_object *obj, bool force)
2672 {
2673         int err;
2674
2675         /* btf_vmlinux could be loaded earlier */
2676         if (obj->btf_vmlinux || obj->gen_loader)
2677                 return 0;
2678
2679         if (!force && !obj_needs_vmlinux_btf(obj))
2680                 return 0;
2681
2682         obj->btf_vmlinux = libbpf_find_kernel_btf();
2683         err = libbpf_get_error(obj->btf_vmlinux);
2684         if (err) {
2685                 pr_warn("Error loading vmlinux BTF: %d\n", err);
2686                 obj->btf_vmlinux = NULL;
2687                 return err;
2688         }
2689         return 0;
2690 }
2691
2692 static int bpf_object__sanitize_and_load_btf(struct bpf_object *obj)
2693 {
2694         struct btf *kern_btf = obj->btf;
2695         bool btf_mandatory, sanitize;
2696         int i, err = 0;
2697
2698         if (!obj->btf)
2699                 return 0;
2700
2701         if (!kernel_supports(obj, FEAT_BTF)) {
2702                 if (kernel_needs_btf(obj)) {
2703                         err = -EOPNOTSUPP;
2704                         goto report;
2705                 }
2706                 pr_debug("Kernel doesn't support BTF, skipping uploading it.\n");
2707                 return 0;
2708         }
2709
2710         /* Even though some subprogs are global/weak, user might prefer more
2711          * permissive BPF verification process that BPF verifier performs for
2712          * static functions, taking into account more context from the caller
2713          * functions. In such case, they need to mark such subprogs with
2714          * __attribute__((visibility("hidden"))) and libbpf will adjust
2715          * corresponding FUNC BTF type to be marked as static and trigger more
2716          * involved BPF verification process.
2717          */
2718         for (i = 0; i < obj->nr_programs; i++) {
2719                 struct bpf_program *prog = &obj->programs[i];
2720                 struct btf_type *t;
2721                 const char *name;
2722                 int j, n;
2723
2724                 if (!prog->mark_btf_static || !prog_is_subprog(obj, prog))
2725                         continue;
2726
2727                 n = btf__get_nr_types(obj->btf);
2728                 for (j = 1; j <= n; j++) {
2729                         t = btf_type_by_id(obj->btf, j);
2730                         if (!btf_is_func(t) || btf_func_linkage(t) != BTF_FUNC_GLOBAL)
2731                                 continue;
2732
2733                         name = btf__str_by_offset(obj->btf, t->name_off);
2734                         if (strcmp(name, prog->name) != 0)
2735                                 continue;
2736
2737                         t->info = btf_type_info(BTF_KIND_FUNC, BTF_FUNC_STATIC, 0);
2738                         break;
2739                 }
2740         }
2741
2742         sanitize = btf_needs_sanitization(obj);
2743         if (sanitize) {
2744                 const void *raw_data;
2745                 __u32 sz;
2746
2747                 /* clone BTF to sanitize a copy and leave the original intact */
2748                 raw_data = btf__get_raw_data(obj->btf, &sz);
2749                 kern_btf = btf__new(raw_data, sz);
2750                 err = libbpf_get_error(kern_btf);
2751                 if (err)
2752                         return err;
2753
2754                 /* enforce 8-byte pointers for BPF-targeted BTFs */
2755                 btf__set_pointer_size(obj->btf, 8);
2756                 bpf_object__sanitize_btf(obj, kern_btf);
2757         }
2758
2759         if (obj->gen_loader) {
2760                 __u32 raw_size = 0;
2761                 const void *raw_data = btf__get_raw_data(kern_btf, &raw_size);
2762
2763                 if (!raw_data)
2764                         return -ENOMEM;
2765                 bpf_gen__load_btf(obj->gen_loader, raw_data, raw_size);
2766                 /* Pretend to have valid FD to pass various fd >= 0 checks.
2767                  * This fd == 0 will not be used with any syscall and will be reset to -1 eventually.
2768                  */
2769                 btf__set_fd(kern_btf, 0);
2770         } else {
2771                 err = btf__load(kern_btf);
2772         }
2773         if (sanitize) {
2774                 if (!err) {
2775                         /* move fd to libbpf's BTF */
2776                         btf__set_fd(obj->btf, btf__fd(kern_btf));
2777                         btf__set_fd(kern_btf, -1);
2778                 }
2779                 btf__free(kern_btf);
2780         }
2781 report:
2782         if (err) {
2783                 btf_mandatory = kernel_needs_btf(obj);
2784                 pr_warn("Error loading .BTF into kernel: %d. %s\n", err,
2785                         btf_mandatory ? "BTF is mandatory, can't proceed."
2786                                       : "BTF is optional, ignoring.");
2787                 if (!btf_mandatory)
2788                         err = 0;
2789         }
2790         return err;
2791 }
2792
2793 static const char *elf_sym_str(const struct bpf_object *obj, size_t off)
2794 {
2795         const char *name;
2796
2797         name = elf_strptr(obj->efile.elf, obj->efile.strtabidx, off);
2798         if (!name) {
2799                 pr_warn("elf: failed to get section name string at offset %zu from %s: %s\n",
2800                         off, obj->path, elf_errmsg(-1));
2801                 return NULL;
2802         }
2803
2804         return name;
2805 }
2806
2807 static const char *elf_sec_str(const struct bpf_object *obj, size_t off)
2808 {
2809         const char *name;
2810
2811         name = elf_strptr(obj->efile.elf, obj->efile.shstrndx, off);
2812         if (!name) {
2813                 pr_warn("elf: failed to get section name string at offset %zu from %s: %s\n",
2814                         off, obj->path, elf_errmsg(-1));
2815                 return NULL;
2816         }
2817
2818         return name;
2819 }
2820
2821 static Elf_Scn *elf_sec_by_idx(const struct bpf_object *obj, size_t idx)
2822 {
2823         Elf_Scn *scn;
2824
2825         scn = elf_getscn(obj->efile.elf, idx);
2826         if (!scn) {
2827                 pr_warn("elf: failed to get section(%zu) from %s: %s\n",
2828                         idx, obj->path, elf_errmsg(-1));
2829                 return NULL;
2830         }
2831         return scn;
2832 }
2833
2834 static Elf_Scn *elf_sec_by_name(const struct bpf_object *obj, const char *name)
2835 {
2836         Elf_Scn *scn = NULL;
2837         Elf *elf = obj->efile.elf;
2838         const char *sec_name;
2839
2840         while ((scn = elf_nextscn(elf, scn)) != NULL) {
2841                 sec_name = elf_sec_name(obj, scn);
2842                 if (!sec_name)
2843                         return NULL;
2844
2845                 if (strcmp(sec_name, name) != 0)
2846                         continue;
2847
2848                 return scn;
2849         }
2850         return NULL;
2851 }
2852
2853 static int elf_sec_hdr(const struct bpf_object *obj, Elf_Scn *scn, GElf_Shdr *hdr)
2854 {
2855         if (!scn)
2856                 return -EINVAL;
2857
2858         if (gelf_getshdr(scn, hdr) != hdr) {
2859                 pr_warn("elf: failed to get section(%zu) header from %s: %s\n",
2860                         elf_ndxscn(scn), obj->path, elf_errmsg(-1));
2861                 return -EINVAL;
2862         }
2863
2864         return 0;
2865 }
2866
2867 static const char *elf_sec_name(const struct bpf_object *obj, Elf_Scn *scn)
2868 {
2869         const char *name;
2870         GElf_Shdr sh;
2871
2872         if (!scn)
2873                 return NULL;
2874
2875         if (elf_sec_hdr(obj, scn, &sh))
2876                 return NULL;
2877
2878         name = elf_sec_str(obj, sh.sh_name);
2879         if (!name) {
2880                 pr_warn("elf: failed to get section(%zu) name from %s: %s\n",
2881                         elf_ndxscn(scn), obj->path, elf_errmsg(-1));
2882                 return NULL;
2883         }
2884
2885         return name;
2886 }
2887
2888 static Elf_Data *elf_sec_data(const struct bpf_object *obj, Elf_Scn *scn)
2889 {
2890         Elf_Data *data;
2891
2892         if (!scn)
2893                 return NULL;
2894
2895         data = elf_getdata(scn, 0);
2896         if (!data) {
2897                 pr_warn("elf: failed to get section(%zu) %s data from %s: %s\n",
2898                         elf_ndxscn(scn), elf_sec_name(obj, scn) ?: "<?>",
2899                         obj->path, elf_errmsg(-1));
2900                 return NULL;
2901         }
2902
2903         return data;
2904 }
2905
2906 static bool is_sec_name_dwarf(const char *name)
2907 {
2908         /* approximation, but the actual list is too long */
2909         return strncmp(name, ".debug_", sizeof(".debug_") - 1) == 0;
2910 }
2911
2912 static bool ignore_elf_section(GElf_Shdr *hdr, const char *name)
2913 {
2914         /* no special handling of .strtab */
2915         if (hdr->sh_type == SHT_STRTAB)
2916                 return true;
2917
2918         /* ignore .llvm_addrsig section as well */
2919         if (hdr->sh_type == SHT_LLVM_ADDRSIG)
2920                 return true;
2921
2922         /* no subprograms will lead to an empty .text section, ignore it */
2923         if (hdr->sh_type == SHT_PROGBITS && hdr->sh_size == 0 &&
2924             strcmp(name, ".text") == 0)
2925                 return true;
2926
2927         /* DWARF sections */
2928         if (is_sec_name_dwarf(name))
2929                 return true;
2930
2931         if (strncmp(name, ".rel", sizeof(".rel") - 1) == 0) {
2932                 name += sizeof(".rel") - 1;
2933                 /* DWARF section relocations */
2934                 if (is_sec_name_dwarf(name))
2935                         return true;
2936
2937                 /* .BTF and .BTF.ext don't need relocations */
2938                 if (strcmp(name, BTF_ELF_SEC) == 0 ||
2939                     strcmp(name, BTF_EXT_ELF_SEC) == 0)
2940                         return true;
2941         }
2942
2943         return false;
2944 }
2945
2946 static int cmp_progs(const void *_a, const void *_b)
2947 {
2948         const struct bpf_program *a = _a;
2949         const struct bpf_program *b = _b;
2950
2951         if (a->sec_idx != b->sec_idx)
2952                 return a->sec_idx < b->sec_idx ? -1 : 1;
2953
2954         /* sec_insn_off can't be the same within the section */
2955         return a->sec_insn_off < b->sec_insn_off ? -1 : 1;
2956 }
2957
2958 static int bpf_object__elf_collect(struct bpf_object *obj)
2959 {
2960         Elf *elf = obj->efile.elf;
2961         Elf_Data *btf_ext_data = NULL;
2962         Elf_Data *btf_data = NULL;
2963         int idx = 0, err = 0;
2964         const char *name;
2965         Elf_Data *data;
2966         Elf_Scn *scn;
2967         GElf_Shdr sh;
2968
2969         /* a bunch of ELF parsing functionality depends on processing symbols,
2970          * so do the first pass and find the symbol table
2971          */
2972         scn = NULL;
2973         while ((scn = elf_nextscn(elf, scn)) != NULL) {
2974                 if (elf_sec_hdr(obj, scn, &sh))
2975                         return -LIBBPF_ERRNO__FORMAT;
2976
2977                 if (sh.sh_type == SHT_SYMTAB) {
2978                         if (obj->efile.symbols) {
2979                                 pr_warn("elf: multiple symbol tables in %s\n", obj->path);
2980                                 return -LIBBPF_ERRNO__FORMAT;
2981                         }
2982
2983                         data = elf_sec_data(obj, scn);
2984                         if (!data)
2985                                 return -LIBBPF_ERRNO__FORMAT;
2986
2987                         obj->efile.symbols = data;
2988                         obj->efile.symbols_shndx = elf_ndxscn(scn);
2989                         obj->efile.strtabidx = sh.sh_link;
2990                 }
2991         }
2992
2993         scn = NULL;
2994         while ((scn = elf_nextscn(elf, scn)) != NULL) {
2995                 idx++;
2996
2997                 if (elf_sec_hdr(obj, scn, &sh))
2998                         return -LIBBPF_ERRNO__FORMAT;
2999
3000                 name = elf_sec_str(obj, sh.sh_name);
3001                 if (!name)
3002                         return -LIBBPF_ERRNO__FORMAT;
3003
3004                 if (ignore_elf_section(&sh, name))
3005                         continue;
3006
3007                 data = elf_sec_data(obj, scn);
3008                 if (!data)
3009                         return -LIBBPF_ERRNO__FORMAT;
3010
3011                 pr_debug("elf: section(%d) %s, size %ld, link %d, flags %lx, type=%d\n",
3012                          idx, name, (unsigned long)data->d_size,
3013                          (int)sh.sh_link, (unsigned long)sh.sh_flags,
3014                          (int)sh.sh_type);
3015
3016                 if (strcmp(name, "license") == 0) {
3017                         err = bpf_object__init_license(obj, data->d_buf, data->d_size);
3018                         if (err)
3019                                 return err;
3020                 } else if (strcmp(name, "version") == 0) {
3021                         err = bpf_object__init_kversion(obj, data->d_buf, data->d_size);
3022                         if (err)
3023                                 return err;
3024                 } else if (strcmp(name, "maps") == 0) {
3025                         obj->efile.maps_shndx = idx;
3026                 } else if (strcmp(name, MAPS_ELF_SEC) == 0) {
3027                         obj->efile.btf_maps_shndx = idx;
3028                 } else if (strcmp(name, BTF_ELF_SEC) == 0) {
3029                         btf_data = data;
3030                 } else if (strcmp(name, BTF_EXT_ELF_SEC) == 0) {
3031                         btf_ext_data = data;
3032                 } else if (sh.sh_type == SHT_SYMTAB) {
3033                         /* already processed during the first pass above */
3034                 } else if (sh.sh_type == SHT_PROGBITS && data->d_size > 0) {
3035                         if (sh.sh_flags & SHF_EXECINSTR) {
3036                                 if (strcmp(name, ".text") == 0)
3037                                         obj->efile.text_shndx = idx;
3038                                 err = bpf_object__add_programs(obj, data, name, idx);
3039                                 if (err)
3040                                         return err;
3041                         } else if (strcmp(name, DATA_SEC) == 0) {
3042                                 obj->efile.data = data;
3043                                 obj->efile.data_shndx = idx;
3044                         } else if (strcmp(name, RODATA_SEC) == 0) {
3045                                 obj->efile.rodata = data;
3046                                 obj->efile.rodata_shndx = idx;
3047                         } else if (strcmp(name, STRUCT_OPS_SEC) == 0) {
3048                                 obj->efile.st_ops_data = data;
3049                                 obj->efile.st_ops_shndx = idx;
3050                         } else {
3051                                 pr_info("elf: skipping unrecognized data section(%d) %s\n",
3052                                         idx, name);
3053                         }
3054                 } else if (sh.sh_type == SHT_REL) {
3055                         int nr_sects = obj->efile.nr_reloc_sects;
3056                         void *sects = obj->efile.reloc_sects;
3057                         int sec = sh.sh_info; /* points to other section */
3058
3059                         /* Only do relo for section with exec instructions */
3060                         if (!section_have_execinstr(obj, sec) &&
3061                             strcmp(name, ".rel" STRUCT_OPS_SEC) &&
3062                             strcmp(name, ".rel" MAPS_ELF_SEC)) {
3063                                 pr_info("elf: skipping relo section(%d) %s for section(%d) %s\n",
3064                                         idx, name, sec,
3065                                         elf_sec_name(obj, elf_sec_by_idx(obj, sec)) ?: "<?>");
3066                                 continue;
3067                         }
3068
3069                         sects = libbpf_reallocarray(sects, nr_sects + 1,
3070                                                     sizeof(*obj->efile.reloc_sects));
3071                         if (!sects)
3072                                 return -ENOMEM;
3073
3074                         obj->efile.reloc_sects = sects;
3075                         obj->efile.nr_reloc_sects++;
3076
3077                         obj->efile.reloc_sects[nr_sects].shdr = sh;
3078                         obj->efile.reloc_sects[nr_sects].data = data;
3079                 } else if (sh.sh_type == SHT_NOBITS && strcmp(name, BSS_SEC) == 0) {
3080                         obj->efile.bss = data;
3081                         obj->efile.bss_shndx = idx;
3082                 } else {
3083                         pr_info("elf: skipping section(%d) %s (size %zu)\n", idx, name,
3084                                 (size_t)sh.sh_size);
3085                 }
3086         }
3087
3088         if (!obj->efile.strtabidx || obj->efile.strtabidx > idx) {
3089                 pr_warn("elf: symbol strings section missing or invalid in %s\n", obj->path);
3090                 return -LIBBPF_ERRNO__FORMAT;
3091         }
3092
3093         /* sort BPF programs by section name and in-section instruction offset
3094          * for faster search */
3095         qsort(obj->programs, obj->nr_programs, sizeof(*obj->programs), cmp_progs);
3096
3097         return bpf_object__init_btf(obj, btf_data, btf_ext_data);
3098 }
3099
3100 static bool sym_is_extern(const GElf_Sym *sym)
3101 {
3102         int bind = GELF_ST_BIND(sym->st_info);
3103         /* externs are symbols w/ type=NOTYPE, bind=GLOBAL|WEAK, section=UND */
3104         return sym->st_shndx == SHN_UNDEF &&
3105                (bind == STB_GLOBAL || bind == STB_WEAK) &&
3106                GELF_ST_TYPE(sym->st_info) == STT_NOTYPE;
3107 }
3108
3109 static bool sym_is_subprog(const GElf_Sym *sym, int text_shndx)
3110 {
3111         int bind = GELF_ST_BIND(sym->st_info);
3112         int type = GELF_ST_TYPE(sym->st_info);
3113
3114         /* in .text section */
3115         if (sym->st_shndx != text_shndx)
3116                 return false;
3117
3118         /* local function */
3119         if (bind == STB_LOCAL && type == STT_SECTION)
3120                 return true;
3121
3122         /* global function */
3123         return bind == STB_GLOBAL && type == STT_FUNC;
3124 }
3125
3126 static int find_extern_btf_id(const struct btf *btf, const char *ext_name)
3127 {
3128         const struct btf_type *t;
3129         const char *tname;
3130         int i, n;
3131
3132         if (!btf)
3133                 return -ESRCH;
3134
3135         n = btf__get_nr_types(btf);
3136         for (i = 1; i <= n; i++) {
3137                 t = btf__type_by_id(btf, i);
3138
3139                 if (!btf_is_var(t) && !btf_is_func(t))
3140                         continue;
3141
3142                 tname = btf__name_by_offset(btf, t->name_off);
3143                 if (strcmp(tname, ext_name))
3144                         continue;
3145
3146                 if (btf_is_var(t) &&
3147                     btf_var(t)->linkage != BTF_VAR_GLOBAL_EXTERN)
3148                         return -EINVAL;
3149
3150                 if (btf_is_func(t) && btf_func_linkage(t) != BTF_FUNC_EXTERN)
3151                         return -EINVAL;
3152
3153                 return i;
3154         }
3155
3156         return -ENOENT;
3157 }
3158
3159 static int find_extern_sec_btf_id(struct btf *btf, int ext_btf_id) {
3160         const struct btf_var_secinfo *vs;
3161         const struct btf_type *t;
3162         int i, j, n;
3163
3164         if (!btf)
3165                 return -ESRCH;
3166
3167         n = btf__get_nr_types(btf);
3168         for (i = 1; i <= n; i++) {
3169                 t = btf__type_by_id(btf, i);
3170
3171                 if (!btf_is_datasec(t))
3172                         continue;
3173
3174                 vs = btf_var_secinfos(t);
3175                 for (j = 0; j < btf_vlen(t); j++, vs++) {
3176                         if (vs->type == ext_btf_id)
3177                                 return i;
3178                 }
3179         }
3180
3181         return -ENOENT;
3182 }
3183
3184 static enum kcfg_type find_kcfg_type(const struct btf *btf, int id,
3185                                      bool *is_signed)
3186 {
3187         const struct btf_type *t;
3188         const char *name;
3189
3190         t = skip_mods_and_typedefs(btf, id, NULL);
3191         name = btf__name_by_offset(btf, t->name_off);
3192
3193         if (is_signed)
3194                 *is_signed = false;
3195         switch (btf_kind(t)) {
3196         case BTF_KIND_INT: {
3197                 int enc = btf_int_encoding(t);
3198
3199                 if (enc & BTF_INT_BOOL)
3200                         return t->size == 1 ? KCFG_BOOL : KCFG_UNKNOWN;
3201                 if (is_signed)
3202                         *is_signed = enc & BTF_INT_SIGNED;
3203                 if (t->size == 1)
3204                         return KCFG_CHAR;
3205                 if (t->size < 1 || t->size > 8 || (t->size & (t->size - 1)))
3206                         return KCFG_UNKNOWN;
3207                 return KCFG_INT;
3208         }
3209         case BTF_KIND_ENUM:
3210                 if (t->size != 4)
3211                         return KCFG_UNKNOWN;
3212                 if (strcmp(name, "libbpf_tristate"))
3213                         return KCFG_UNKNOWN;
3214                 return KCFG_TRISTATE;
3215         case BTF_KIND_ARRAY:
3216                 if (btf_array(t)->nelems == 0)
3217                         return KCFG_UNKNOWN;
3218                 if (find_kcfg_type(btf, btf_array(t)->type, NULL) != KCFG_CHAR)
3219                         return KCFG_UNKNOWN;
3220                 return KCFG_CHAR_ARR;
3221         default:
3222                 return KCFG_UNKNOWN;
3223         }
3224 }
3225
3226 static int cmp_externs(const void *_a, const void *_b)
3227 {
3228         const struct extern_desc *a = _a;
3229         const struct extern_desc *b = _b;
3230
3231         if (a->type != b->type)
3232                 return a->type < b->type ? -1 : 1;
3233
3234         if (a->type == EXT_KCFG) {
3235                 /* descending order by alignment requirements */
3236                 if (a->kcfg.align != b->kcfg.align)
3237                         return a->kcfg.align > b->kcfg.align ? -1 : 1;
3238                 /* ascending order by size, within same alignment class */
3239                 if (a->kcfg.sz != b->kcfg.sz)
3240                         return a->kcfg.sz < b->kcfg.sz ? -1 : 1;
3241         }
3242
3243         /* resolve ties by name */
3244         return strcmp(a->name, b->name);
3245 }
3246
3247 static int find_int_btf_id(const struct btf *btf)
3248 {
3249         const struct btf_type *t;
3250         int i, n;
3251
3252         n = btf__get_nr_types(btf);
3253         for (i = 1; i <= n; i++) {
3254                 t = btf__type_by_id(btf, i);
3255
3256                 if (btf_is_int(t) && btf_int_bits(t) == 32)
3257                         return i;
3258         }
3259
3260         return 0;
3261 }
3262
3263 static int add_dummy_ksym_var(struct btf *btf)
3264 {
3265         int i, int_btf_id, sec_btf_id, dummy_var_btf_id;
3266         const struct btf_var_secinfo *vs;
3267         const struct btf_type *sec;
3268
3269         if (!btf)
3270                 return 0;
3271
3272         sec_btf_id = btf__find_by_name_kind(btf, KSYMS_SEC,
3273                                             BTF_KIND_DATASEC);
3274         if (sec_btf_id < 0)
3275                 return 0;
3276
3277         sec = btf__type_by_id(btf, sec_btf_id);
3278         vs = btf_var_secinfos(sec);
3279         for (i = 0; i < btf_vlen(sec); i++, vs++) {
3280                 const struct btf_type *vt;
3281
3282                 vt = btf__type_by_id(btf, vs->type);
3283                 if (btf_is_func(vt))
3284                         break;
3285         }
3286
3287         /* No func in ksyms sec.  No need to add dummy var. */
3288         if (i == btf_vlen(sec))
3289                 return 0;
3290
3291         int_btf_id = find_int_btf_id(btf);
3292         dummy_var_btf_id = btf__add_var(btf,
3293                                         "dummy_ksym",
3294                                         BTF_VAR_GLOBAL_ALLOCATED,
3295                                         int_btf_id);
3296         if (dummy_var_btf_id < 0)
3297                 pr_warn("cannot create a dummy_ksym var\n");
3298
3299         return dummy_var_btf_id;
3300 }
3301
3302 static int bpf_object__collect_externs(struct bpf_object *obj)
3303 {
3304         struct btf_type *sec, *kcfg_sec = NULL, *ksym_sec = NULL;
3305         const struct btf_type *t;
3306         struct extern_desc *ext;
3307         int i, n, off, dummy_var_btf_id;
3308         const char *ext_name, *sec_name;
3309         Elf_Scn *scn;
3310         GElf_Shdr sh;
3311
3312         if (!obj->efile.symbols)
3313                 return 0;
3314
3315         scn = elf_sec_by_idx(obj, obj->efile.symbols_shndx);
3316         if (elf_sec_hdr(obj, scn, &sh))
3317                 return -LIBBPF_ERRNO__FORMAT;
3318
3319         dummy_var_btf_id = add_dummy_ksym_var(obj->btf);
3320         if (dummy_var_btf_id < 0)
3321                 return dummy_var_btf_id;
3322
3323         n = sh.sh_size / sh.sh_entsize;
3324         pr_debug("looking for externs among %d symbols...\n", n);
3325
3326         for (i = 0; i < n; i++) {
3327                 GElf_Sym sym;
3328
3329                 if (!gelf_getsym(obj->efile.symbols, i, &sym))
3330                         return -LIBBPF_ERRNO__FORMAT;
3331                 if (!sym_is_extern(&sym))
3332                         continue;
3333                 ext_name = elf_sym_str(obj, sym.st_name);
3334                 if (!ext_name || !ext_name[0])
3335                         continue;
3336
3337                 ext = obj->externs;
3338                 ext = libbpf_reallocarray(ext, obj->nr_extern + 1, sizeof(*ext));
3339                 if (!ext)
3340                         return -ENOMEM;
3341                 obj->externs = ext;
3342                 ext = &ext[obj->nr_extern];
3343                 memset(ext, 0, sizeof(*ext));
3344                 obj->nr_extern++;
3345
3346                 ext->btf_id = find_extern_btf_id(obj->btf, ext_name);
3347                 if (ext->btf_id <= 0) {
3348                         pr_warn("failed to find BTF for extern '%s': %d\n",
3349                                 ext_name, ext->btf_id);
3350                         return ext->btf_id;
3351                 }
3352                 t = btf__type_by_id(obj->btf, ext->btf_id);
3353                 ext->name = btf__name_by_offset(obj->btf, t->name_off);
3354                 ext->sym_idx = i;
3355                 ext->is_weak = GELF_ST_BIND(sym.st_info) == STB_WEAK;
3356
3357                 ext->sec_btf_id = find_extern_sec_btf_id(obj->btf, ext->btf_id);
3358                 if (ext->sec_btf_id <= 0) {
3359                         pr_warn("failed to find BTF for extern '%s' [%d] section: %d\n",
3360                                 ext_name, ext->btf_id, ext->sec_btf_id);
3361                         return ext->sec_btf_id;
3362                 }
3363                 sec = (void *)btf__type_by_id(obj->btf, ext->sec_btf_id);
3364                 sec_name = btf__name_by_offset(obj->btf, sec->name_off);
3365
3366                 if (strcmp(sec_name, KCONFIG_SEC) == 0) {
3367                         if (btf_is_func(t)) {
3368                                 pr_warn("extern function %s is unsupported under %s section\n",
3369                                         ext->name, KCONFIG_SEC);
3370                                 return -ENOTSUP;
3371                         }
3372                         kcfg_sec = sec;
3373                         ext->type = EXT_KCFG;
3374                         ext->kcfg.sz = btf__resolve_size(obj->btf, t->type);
3375                         if (ext->kcfg.sz <= 0) {
3376                                 pr_warn("failed to resolve size of extern (kcfg) '%s': %d\n",
3377                                         ext_name, ext->kcfg.sz);
3378                                 return ext->kcfg.sz;
3379                         }
3380                         ext->kcfg.align = btf__align_of(obj->btf, t->type);
3381                         if (ext->kcfg.align <= 0) {
3382                                 pr_warn("failed to determine alignment of extern (kcfg) '%s': %d\n",
3383                                         ext_name, ext->kcfg.align);
3384                                 return -EINVAL;
3385                         }
3386                         ext->kcfg.type = find_kcfg_type(obj->btf, t->type,
3387                                                         &ext->kcfg.is_signed);
3388                         if (ext->kcfg.type == KCFG_UNKNOWN) {
3389                                 pr_warn("extern (kcfg) '%s' type is unsupported\n", ext_name);
3390                                 return -ENOTSUP;
3391                         }
3392                 } else if (strcmp(sec_name, KSYMS_SEC) == 0) {
3393                         if (btf_is_func(t) && ext->is_weak) {
3394                                 pr_warn("extern weak function %s is unsupported\n",
3395                                         ext->name);
3396                                 return -ENOTSUP;
3397                         }
3398                         ksym_sec = sec;
3399                         ext->type = EXT_KSYM;
3400                         skip_mods_and_typedefs(obj->btf, t->type,
3401                                                &ext->ksym.type_id);
3402                 } else {
3403                         pr_warn("unrecognized extern section '%s'\n", sec_name);
3404                         return -ENOTSUP;
3405                 }
3406         }
3407         pr_debug("collected %d externs total\n", obj->nr_extern);
3408
3409         if (!obj->nr_extern)
3410                 return 0;
3411
3412         /* sort externs by type, for kcfg ones also by (align, size, name) */
3413         qsort(obj->externs, obj->nr_extern, sizeof(*ext), cmp_externs);
3414
3415         /* for .ksyms section, we need to turn all externs into allocated
3416          * variables in BTF to pass kernel verification; we do this by
3417          * pretending that each extern is a 8-byte variable
3418          */
3419         if (ksym_sec) {
3420                 /* find existing 4-byte integer type in BTF to use for fake
3421                  * extern variables in DATASEC
3422                  */
3423                 int int_btf_id = find_int_btf_id(obj->btf);
3424                 /* For extern function, a dummy_var added earlier
3425                  * will be used to replace the vs->type and
3426                  * its name string will be used to refill
3427                  * the missing param's name.
3428                  */
3429                 const struct btf_type *dummy_var;
3430
3431                 dummy_var = btf__type_by_id(obj->btf, dummy_var_btf_id);
3432                 for (i = 0; i < obj->nr_extern; i++) {
3433                         ext = &obj->externs[i];
3434                         if (ext->type != EXT_KSYM)
3435                                 continue;
3436                         pr_debug("extern (ksym) #%d: symbol %d, name %s\n",
3437                                  i, ext->sym_idx, ext->name);
3438                 }
3439
3440                 sec = ksym_sec;
3441                 n = btf_vlen(sec);
3442                 for (i = 0, off = 0; i < n; i++, off += sizeof(int)) {
3443                         struct btf_var_secinfo *vs = btf_var_secinfos(sec) + i;
3444                         struct btf_type *vt;
3445
3446                         vt = (void *)btf__type_by_id(obj->btf, vs->type);
3447                         ext_name = btf__name_by_offset(obj->btf, vt->name_off);
3448                         ext = find_extern_by_name(obj, ext_name);
3449                         if (!ext) {
3450                                 pr_warn("failed to find extern definition for BTF %s '%s'\n",
3451                                         btf_kind_str(vt), ext_name);
3452                                 return -ESRCH;
3453                         }
3454                         if (btf_is_func(vt)) {
3455                                 const struct btf_type *func_proto;
3456                                 struct btf_param *param;
3457                                 int j;
3458
3459                                 func_proto = btf__type_by_id(obj->btf,
3460                                                              vt->type);
3461                                 param = btf_params(func_proto);
3462                                 /* Reuse the dummy_var string if the
3463                                  * func proto does not have param name.
3464                                  */
3465                                 for (j = 0; j < btf_vlen(func_proto); j++)
3466                                         if (param[j].type && !param[j].name_off)
3467                                                 param[j].name_off =
3468                                                         dummy_var->name_off;
3469                                 vs->type = dummy_var_btf_id;
3470                                 vt->info &= ~0xffff;
3471                                 vt->info |= BTF_FUNC_GLOBAL;
3472                         } else {
3473                                 btf_var(vt)->linkage = BTF_VAR_GLOBAL_ALLOCATED;
3474                                 vt->type = int_btf_id;
3475                         }
3476                         vs->offset = off;
3477                         vs->size = sizeof(int);
3478                 }
3479                 sec->size = off;
3480         }
3481
3482         if (kcfg_sec) {
3483                 sec = kcfg_sec;
3484                 /* for kcfg externs calculate their offsets within a .kconfig map */
3485                 off = 0;
3486                 for (i = 0; i < obj->nr_extern; i++) {
3487                         ext = &obj->externs[i];
3488                         if (ext->type != EXT_KCFG)
3489                                 continue;
3490
3491                         ext->kcfg.data_off = roundup(off, ext->kcfg.align);
3492                         off = ext->kcfg.data_off + ext->kcfg.sz;
3493                         pr_debug("extern (kcfg) #%d: symbol %d, off %u, name %s\n",
3494                                  i, ext->sym_idx, ext->kcfg.data_off, ext->name);
3495                 }
3496                 sec->size = off;
3497                 n = btf_vlen(sec);
3498                 for (i = 0; i < n; i++) {
3499                         struct btf_var_secinfo *vs = btf_var_secinfos(sec) + i;
3500
3501                         t = btf__type_by_id(obj->btf, vs->type);
3502                         ext_name = btf__name_by_offset(obj->btf, t->name_off);
3503                         ext = find_extern_by_name(obj, ext_name);
3504                         if (!ext) {
3505                                 pr_warn("failed to find extern definition for BTF var '%s'\n",
3506                                         ext_name);
3507                                 return -ESRCH;
3508                         }
3509                         btf_var(t)->linkage = BTF_VAR_GLOBAL_ALLOCATED;
3510                         vs->offset = ext->kcfg.data_off;
3511                 }
3512         }
3513         return 0;
3514 }
3515
3516 struct bpf_program *
3517 bpf_object__find_program_by_title(const struct bpf_object *obj,
3518                                   const char *title)
3519 {
3520         struct bpf_program *pos;
3521
3522         bpf_object__for_each_program(pos, obj) {
3523                 if (pos->sec_name && !strcmp(pos->sec_name, title))
3524                         return pos;
3525         }
3526         return errno = ENOENT, NULL;
3527 }
3528
3529 static bool prog_is_subprog(const struct bpf_object *obj,
3530                             const struct bpf_program *prog)
3531 {
3532         /* For legacy reasons, libbpf supports an entry-point BPF programs
3533          * without SEC() attribute, i.e., those in the .text section. But if
3534          * there are 2 or more such programs in the .text section, they all
3535          * must be subprograms called from entry-point BPF programs in
3536          * designated SEC()'tions, otherwise there is no way to distinguish
3537          * which of those programs should be loaded vs which are a subprogram.
3538          * Similarly, if there is a function/program in .text and at least one
3539          * other BPF program with custom SEC() attribute, then we just assume
3540          * .text programs are subprograms (even if they are not called from
3541          * other programs), because libbpf never explicitly supported mixing
3542          * SEC()-designated BPF programs and .text entry-point BPF programs.
3543          */
3544         return prog->sec_idx == obj->efile.text_shndx && obj->nr_programs > 1;
3545 }
3546
3547 struct bpf_program *
3548 bpf_object__find_program_by_name(const struct bpf_object *obj,
3549                                  const char *name)
3550 {
3551         struct bpf_program *prog;
3552
3553         bpf_object__for_each_program(prog, obj) {
3554                 if (prog_is_subprog(obj, prog))
3555                         continue;
3556                 if (!strcmp(prog->name, name))
3557                         return prog;
3558         }
3559         return errno = ENOENT, NULL;
3560 }
3561
3562 static bool bpf_object__shndx_is_data(const struct bpf_object *obj,
3563                                       int shndx)
3564 {
3565         return shndx == obj->efile.data_shndx ||
3566                shndx == obj->efile.bss_shndx ||
3567                shndx == obj->efile.rodata_shndx;
3568 }
3569
3570 static bool bpf_object__shndx_is_maps(const struct bpf_object *obj,
3571                                       int shndx)
3572 {
3573         return shndx == obj->efile.maps_shndx ||
3574                shndx == obj->efile.btf_maps_shndx;
3575 }
3576
3577 static enum libbpf_map_type
3578 bpf_object__section_to_libbpf_map_type(const struct bpf_object *obj, int shndx)
3579 {
3580         if (shndx == obj->efile.data_shndx)
3581                 return LIBBPF_MAP_DATA;
3582         else if (shndx == obj->efile.bss_shndx)
3583                 return LIBBPF_MAP_BSS;
3584         else if (shndx == obj->efile.rodata_shndx)
3585                 return LIBBPF_MAP_RODATA;
3586         else if (shndx == obj->efile.symbols_shndx)
3587                 return LIBBPF_MAP_KCONFIG;
3588         else
3589                 return LIBBPF_MAP_UNSPEC;
3590 }
3591
3592 static int bpf_program__record_reloc(struct bpf_program *prog,
3593                                      struct reloc_desc *reloc_desc,
3594                                      __u32 insn_idx, const char *sym_name,
3595                                      const GElf_Sym *sym, const GElf_Rel *rel)
3596 {
3597         struct bpf_insn *insn = &prog->insns[insn_idx];
3598         size_t map_idx, nr_maps = prog->obj->nr_maps;
3599         struct bpf_object *obj = prog->obj;
3600         __u32 shdr_idx = sym->st_shndx;
3601         enum libbpf_map_type type;
3602         const char *sym_sec_name;
3603         struct bpf_map *map;
3604
3605         if (!is_call_insn(insn) && !is_ldimm64_insn(insn)) {
3606                 pr_warn("prog '%s': invalid relo against '%s' for insns[%d].code 0x%x\n",
3607                         prog->name, sym_name, insn_idx, insn->code);
3608                 return -LIBBPF_ERRNO__RELOC;
3609         }
3610
3611         if (sym_is_extern(sym)) {
3612                 int sym_idx = GELF_R_SYM(rel->r_info);
3613                 int i, n = obj->nr_extern;
3614                 struct extern_desc *ext;
3615
3616                 for (i = 0; i < n; i++) {
3617                         ext = &obj->externs[i];
3618                         if (ext->sym_idx == sym_idx)
3619                                 break;
3620                 }
3621                 if (i >= n) {
3622                         pr_warn("prog '%s': extern relo failed to find extern for '%s' (%d)\n",
3623                                 prog->name, sym_name, sym_idx);
3624                         return -LIBBPF_ERRNO__RELOC;
3625                 }
3626                 pr_debug("prog '%s': found extern #%d '%s' (sym %d) for insn #%u\n",
3627                          prog->name, i, ext->name, ext->sym_idx, insn_idx);
3628                 if (insn->code == (BPF_JMP | BPF_CALL))
3629                         reloc_desc->type = RELO_EXTERN_FUNC;
3630                 else
3631                         reloc_desc->type = RELO_EXTERN_VAR;
3632                 reloc_desc->insn_idx = insn_idx;
3633                 reloc_desc->sym_off = i; /* sym_off stores extern index */
3634                 return 0;
3635         }
3636
3637         /* sub-program call relocation */
3638         if (is_call_insn(insn)) {
3639                 if (insn->src_reg != BPF_PSEUDO_CALL) {
3640                         pr_warn("prog '%s': incorrect bpf_call opcode\n", prog->name);
3641                         return -LIBBPF_ERRNO__RELOC;
3642                 }
3643                 /* text_shndx can be 0, if no default "main" program exists */
3644                 if (!shdr_idx || shdr_idx != obj->efile.text_shndx) {
3645                         sym_sec_name = elf_sec_name(obj, elf_sec_by_idx(obj, shdr_idx));
3646                         pr_warn("prog '%s': bad call relo against '%s' in section '%s'\n",
3647                                 prog->name, sym_name, sym_sec_name);
3648                         return -LIBBPF_ERRNO__RELOC;
3649                 }
3650                 if (sym->st_value % BPF_INSN_SZ) {
3651                         pr_warn("prog '%s': bad call relo against '%s' at offset %zu\n",
3652                                 prog->name, sym_name, (size_t)sym->st_value);
3653                         return -LIBBPF_ERRNO__RELOC;
3654                 }
3655                 reloc_desc->type = RELO_CALL;
3656                 reloc_desc->insn_idx = insn_idx;
3657                 reloc_desc->sym_off = sym->st_value;
3658                 return 0;
3659         }
3660
3661         if (!shdr_idx || shdr_idx >= SHN_LORESERVE) {
3662                 pr_warn("prog '%s': invalid relo against '%s' in special section 0x%x; forgot to initialize global var?..\n",
3663                         prog->name, sym_name, shdr_idx);
3664                 return -LIBBPF_ERRNO__RELOC;
3665         }
3666
3667         /* loading subprog addresses */
3668         if (sym_is_subprog(sym, obj->efile.text_shndx)) {
3669                 /* global_func: sym->st_value = offset in the section, insn->imm = 0.
3670                  * local_func: sym->st_value = 0, insn->imm = offset in the section.
3671                  */
3672                 if ((sym->st_value % BPF_INSN_SZ) || (insn->imm % BPF_INSN_SZ)) {
3673                         pr_warn("prog '%s': bad subprog addr relo against '%s' at offset %zu+%d\n",
3674                                 prog->name, sym_name, (size_t)sym->st_value, insn->imm);
3675                         return -LIBBPF_ERRNO__RELOC;
3676                 }
3677
3678                 reloc_desc->type = RELO_SUBPROG_ADDR;
3679                 reloc_desc->insn_idx = insn_idx;
3680                 reloc_desc->sym_off = sym->st_value;
3681                 return 0;
3682         }
3683
3684         type = bpf_object__section_to_libbpf_map_type(obj, shdr_idx);
3685         sym_sec_name = elf_sec_name(obj, elf_sec_by_idx(obj, shdr_idx));
3686
3687         /* generic map reference relocation */
3688         if (type == LIBBPF_MAP_UNSPEC) {
3689                 if (!bpf_object__shndx_is_maps(obj, shdr_idx)) {
3690                         pr_warn("prog '%s': bad map relo against '%s' in section '%s'\n",
3691                                 prog->name, sym_name, sym_sec_name);
3692                         return -LIBBPF_ERRNO__RELOC;
3693                 }
3694                 for (map_idx = 0; map_idx < nr_maps; map_idx++) {
3695                         map = &obj->maps[map_idx];
3696                         if (map->libbpf_type != type ||
3697                             map->sec_idx != sym->st_shndx ||
3698                             map->sec_offset != sym->st_value)
3699                                 continue;
3700                         pr_debug("prog '%s': found map %zd (%s, sec %d, off %zu) for insn #%u\n",
3701                                  prog->name, map_idx, map->name, map->sec_idx,
3702                                  map->sec_offset, insn_idx);
3703                         break;
3704                 }
3705                 if (map_idx >= nr_maps) {
3706                         pr_warn("prog '%s': map relo failed to find map for section '%s', off %zu\n",
3707                                 prog->name, sym_sec_name, (size_t)sym->st_value);
3708                         return -LIBBPF_ERRNO__RELOC;
3709                 }
3710                 reloc_desc->type = RELO_LD64;
3711                 reloc_desc->insn_idx = insn_idx;
3712                 reloc_desc->map_idx = map_idx;
3713                 reloc_desc->sym_off = 0; /* sym->st_value determines map_idx */
3714                 return 0;
3715         }
3716
3717         /* global data map relocation */
3718         if (!bpf_object__shndx_is_data(obj, shdr_idx)) {
3719                 pr_warn("prog '%s': bad data relo against section '%s'\n",
3720                         prog->name, sym_sec_name);
3721                 return -LIBBPF_ERRNO__RELOC;
3722         }
3723         for (map_idx = 0; map_idx < nr_maps; map_idx++) {
3724                 map = &obj->maps[map_idx];
3725                 if (map->libbpf_type != type)
3726                         continue;
3727                 pr_debug("prog '%s': found data map %zd (%s, sec %d, off %zu) for insn %u\n",
3728                          prog->name, map_idx, map->name, map->sec_idx,
3729                          map->sec_offset, insn_idx);
3730                 break;
3731         }
3732         if (map_idx >= nr_maps) {
3733                 pr_warn("prog '%s': data relo failed to find map for section '%s'\n",
3734                         prog->name, sym_sec_name);
3735                 return -LIBBPF_ERRNO__RELOC;
3736         }
3737
3738         reloc_desc->type = RELO_DATA;
3739         reloc_desc->insn_idx = insn_idx;
3740         reloc_desc->map_idx = map_idx;
3741         reloc_desc->sym_off = sym->st_value;
3742         return 0;
3743 }
3744
3745 static bool prog_contains_insn(const struct bpf_program *prog, size_t insn_idx)
3746 {
3747         return insn_idx >= prog->sec_insn_off &&
3748                insn_idx < prog->sec_insn_off + prog->sec_insn_cnt;
3749 }
3750
3751 static struct bpf_program *find_prog_by_sec_insn(const struct bpf_object *obj,
3752                                                  size_t sec_idx, size_t insn_idx)
3753 {
3754         int l = 0, r = obj->nr_programs - 1, m;
3755         struct bpf_program *prog;
3756
3757         while (l < r) {
3758                 m = l + (r - l + 1) / 2;
3759                 prog = &obj->programs[m];
3760
3761                 if (prog->sec_idx < sec_idx ||
3762                     (prog->sec_idx == sec_idx && prog->sec_insn_off <= insn_idx))
3763                         l = m;
3764                 else
3765                         r = m - 1;
3766         }
3767         /* matching program could be at index l, but it still might be the
3768          * wrong one, so we need to double check conditions for the last time
3769          */
3770         prog = &obj->programs[l];
3771         if (prog->sec_idx == sec_idx && prog_contains_insn(prog, insn_idx))
3772                 return prog;
3773         return NULL;
3774 }
3775
3776 static int
3777 bpf_object__collect_prog_relos(struct bpf_object *obj, GElf_Shdr *shdr, Elf_Data *data)
3778 {
3779         Elf_Data *symbols = obj->efile.symbols;
3780         const char *relo_sec_name, *sec_name;
3781         size_t sec_idx = shdr->sh_info;
3782         struct bpf_program *prog;
3783         struct reloc_desc *relos;
3784         int err, i, nrels;
3785         const char *sym_name;
3786         __u32 insn_idx;
3787         Elf_Scn *scn;
3788         Elf_Data *scn_data;
3789         GElf_Sym sym;
3790         GElf_Rel rel;
3791
3792         scn = elf_sec_by_idx(obj, sec_idx);
3793         scn_data = elf_sec_data(obj, scn);
3794
3795         relo_sec_name = elf_sec_str(obj, shdr->sh_name);
3796         sec_name = elf_sec_name(obj, scn);
3797         if (!relo_sec_name || !sec_name)
3798                 return -EINVAL;
3799
3800         pr_debug("sec '%s': collecting relocation for section(%zu) '%s'\n",
3801                  relo_sec_name, sec_idx, sec_name);
3802         nrels = shdr->sh_size / shdr->sh_entsize;
3803
3804         for (i = 0; i < nrels; i++) {
3805                 if (!gelf_getrel(data, i, &rel)) {
3806                         pr_warn("sec '%s': failed to get relo #%d\n", relo_sec_name, i);
3807                         return -LIBBPF_ERRNO__FORMAT;
3808                 }
3809                 if (!gelf_getsym(symbols, GELF_R_SYM(rel.r_info), &sym)) {
3810                         pr_warn("sec '%s': symbol 0x%zx not found for relo #%d\n",
3811                                 relo_sec_name, (size_t)GELF_R_SYM(rel.r_info), i);
3812                         return -LIBBPF_ERRNO__FORMAT;
3813                 }
3814
3815                 if (rel.r_offset % BPF_INSN_SZ || rel.r_offset >= scn_data->d_size) {
3816                         pr_warn("sec '%s': invalid offset 0x%zx for relo #%d\n",
3817                                 relo_sec_name, (size_t)GELF_R_SYM(rel.r_info), i);
3818                         return -LIBBPF_ERRNO__FORMAT;
3819                 }
3820
3821                 insn_idx = rel.r_offset / BPF_INSN_SZ;
3822                 /* relocations against static functions are recorded as
3823                  * relocations against the section that contains a function;
3824                  * in such case, symbol will be STT_SECTION and sym.st_name
3825                  * will point to empty string (0), so fetch section name
3826                  * instead
3827                  */
3828                 if (GELF_ST_TYPE(sym.st_info) == STT_SECTION && sym.st_name == 0)
3829                         sym_name = elf_sec_name(obj, elf_sec_by_idx(obj, sym.st_shndx));
3830                 else
3831                         sym_name = elf_sym_str(obj, sym.st_name);
3832                 sym_name = sym_name ?: "<?";
3833
3834                 pr_debug("sec '%s': relo #%d: insn #%u against '%s'\n",
3835                          relo_sec_name, i, insn_idx, sym_name);
3836
3837                 prog = find_prog_by_sec_insn(obj, sec_idx, insn_idx);
3838                 if (!prog) {
3839                         pr_debug("sec '%s': relo #%d: couldn't find program in section '%s' for insn #%u, probably overridden weak function, skipping...\n",
3840                                 relo_sec_name, i, sec_name, insn_idx);
3841                         continue;
3842                 }
3843
3844                 relos = libbpf_reallocarray(prog->reloc_desc,
3845                                             prog->nr_reloc + 1, sizeof(*relos));
3846                 if (!relos)
3847                         return -ENOMEM;
3848                 prog->reloc_desc = relos;
3849
3850                 /* adjust insn_idx to local BPF program frame of reference */
3851                 insn_idx -= prog->sec_insn_off;
3852                 err = bpf_program__record_reloc(prog, &relos[prog->nr_reloc],
3853                                                 insn_idx, sym_name, &sym, &rel);
3854                 if (err)
3855                         return err;
3856
3857                 prog->nr_reloc++;
3858         }
3859         return 0;
3860 }
3861
3862 static int bpf_map_find_btf_info(struct bpf_object *obj, struct bpf_map *map)
3863 {
3864         struct bpf_map_def *def = &map->def;
3865         __u32 key_type_id = 0, value_type_id = 0;
3866         int ret;
3867
3868         /* if it's BTF-defined map, we don't need to search for type IDs.
3869          * For struct_ops map, it does not need btf_key_type_id and
3870          * btf_value_type_id.
3871          */
3872         if (map->sec_idx == obj->efile.btf_maps_shndx ||
3873             bpf_map__is_struct_ops(map))
3874                 return 0;
3875
3876         if (!bpf_map__is_internal(map)) {
3877                 ret = btf__get_map_kv_tids(obj->btf, map->name, def->key_size,
3878                                            def->value_size, &key_type_id,
3879                                            &value_type_id);
3880         } else {
3881                 /*
3882                  * LLVM annotates global data differently in BTF, that is,
3883                  * only as '.data', '.bss' or '.rodata'.
3884                  */
3885                 ret = btf__find_by_name(obj->btf,
3886                                 libbpf_type_to_btf_name[map->libbpf_type]);
3887         }
3888         if (ret < 0)
3889                 return ret;
3890
3891         map->btf_key_type_id = key_type_id;
3892         map->btf_value_type_id = bpf_map__is_internal(map) ?
3893                                  ret : value_type_id;
3894         return 0;
3895 }
3896
3897 int bpf_map__reuse_fd(struct bpf_map *map, int fd)
3898 {
3899         struct bpf_map_info info = {};
3900         __u32 len = sizeof(info);
3901         int new_fd, err;
3902         char *new_name;
3903
3904         err = bpf_obj_get_info_by_fd(fd, &info, &len);
3905         if (err)
3906                 return libbpf_err(err);
3907
3908         new_name = strdup(info.name);
3909         if (!new_name)
3910                 return libbpf_err(-errno);
3911
3912         new_fd = open("/", O_RDONLY | O_CLOEXEC);
3913         if (new_fd < 0) {
3914                 err = -errno;
3915                 goto err_free_new_name;
3916         }
3917
3918         new_fd = dup3(fd, new_fd, O_CLOEXEC);
3919         if (new_fd < 0) {
3920                 err = -errno;
3921                 goto err_close_new_fd;
3922         }
3923
3924         err = zclose(map->fd);
3925         if (err) {
3926                 err = -errno;
3927                 goto err_close_new_fd;
3928         }
3929         free(map->name);
3930
3931         map->fd = new_fd;
3932         map->name = new_name;
3933         map->def.type = info.type;
3934         map->def.key_size = info.key_size;
3935         map->def.value_size = info.value_size;
3936         map->def.max_entries = info.max_entries;
3937         map->def.map_flags = info.map_flags;
3938         map->btf_key_type_id = info.btf_key_type_id;
3939         map->btf_value_type_id = info.btf_value_type_id;
3940         map->reused = true;
3941
3942         return 0;
3943
3944 err_close_new_fd:
3945         close(new_fd);
3946 err_free_new_name:
3947         free(new_name);
3948         return libbpf_err(err);
3949 }
3950
3951 __u32 bpf_map__max_entries(const struct bpf_map *map)
3952 {
3953         return map->def.max_entries;
3954 }
3955
3956 struct bpf_map *bpf_map__inner_map(struct bpf_map *map)
3957 {
3958         if (!bpf_map_type__is_map_in_map(map->def.type))
3959                 return errno = EINVAL, NULL;
3960
3961         return map->inner_map;
3962 }
3963
3964 int bpf_map__set_max_entries(struct bpf_map *map, __u32 max_entries)
3965 {
3966         if (map->fd >= 0)
3967                 return libbpf_err(-EBUSY);
3968         map->def.max_entries = max_entries;
3969         return 0;
3970 }
3971
3972 int bpf_map__resize(struct bpf_map *map, __u32 max_entries)
3973 {
3974         if (!map || !max_entries)
3975                 return libbpf_err(-EINVAL);
3976
3977         return bpf_map__set_max_entries(map, max_entries);
3978 }
3979
3980 static int
3981 bpf_object__probe_loading(struct bpf_object *obj)
3982 {
3983         struct bpf_load_program_attr attr;
3984         char *cp, errmsg[STRERR_BUFSIZE];
3985         struct bpf_insn insns[] = {
3986                 BPF_MOV64_IMM(BPF_REG_0, 0),
3987                 BPF_EXIT_INSN(),
3988         };
3989         int ret;
3990
3991         if (obj->gen_loader)
3992                 return 0;
3993
3994         /* make sure basic loading works */
3995
3996         memset(&attr, 0, sizeof(attr));
3997         attr.prog_type = BPF_PROG_TYPE_SOCKET_FILTER;
3998         attr.insns = insns;
3999         attr.insns_cnt = ARRAY_SIZE(insns);
4000         attr.license = "GPL";
4001
4002         ret = bpf_load_program_xattr(&attr, NULL, 0);
4003         if (ret < 0) {
4004                 attr.prog_type = BPF_PROG_TYPE_TRACEPOINT;
4005                 ret = bpf_load_program_xattr(&attr, NULL, 0);
4006         }
4007         if (ret < 0) {
4008                 ret = errno;
4009                 cp = libbpf_strerror_r(ret, errmsg, sizeof(errmsg));
4010                 pr_warn("Error in %s():%s(%d). Couldn't load trivial BPF "
4011                         "program. Make sure your kernel supports BPF "
4012                         "(CONFIG_BPF_SYSCALL=y) and/or that RLIMIT_MEMLOCK is "
4013                         "set to big enough value.\n", __func__, cp, ret);
4014                 return -ret;
4015         }
4016         close(ret);
4017
4018         return 0;
4019 }
4020
4021 static int probe_fd(int fd)
4022 {
4023         if (fd >= 0)
4024                 close(fd);
4025         return fd >= 0;
4026 }
4027
4028 static int probe_kern_prog_name(void)
4029 {
4030         struct bpf_load_program_attr attr;
4031         struct bpf_insn insns[] = {
4032                 BPF_MOV64_IMM(BPF_REG_0, 0),
4033                 BPF_EXIT_INSN(),
4034         };
4035         int ret;
4036
4037         /* make sure loading with name works */
4038
4039         memset(&attr, 0, sizeof(attr));
4040         attr.prog_type = BPF_PROG_TYPE_SOCKET_FILTER;
4041         attr.insns = insns;
4042         attr.insns_cnt = ARRAY_SIZE(insns);
4043         attr.license = "GPL";
4044         attr.name = "test";
4045         ret = bpf_load_program_xattr(&attr, NULL, 0);
4046         return probe_fd(ret);
4047 }
4048
4049 static int probe_kern_global_data(void)
4050 {
4051         struct bpf_load_program_attr prg_attr;
4052         struct bpf_create_map_attr map_attr;
4053         char *cp, errmsg[STRERR_BUFSIZE];
4054         struct bpf_insn insns[] = {
4055                 BPF_LD_MAP_VALUE(BPF_REG_1, 0, 16),
4056                 BPF_ST_MEM(BPF_DW, BPF_REG_1, 0, 42),
4057                 BPF_MOV64_IMM(BPF_REG_0, 0),
4058                 BPF_EXIT_INSN(),
4059         };
4060         int ret, map;
4061
4062         memset(&map_attr, 0, sizeof(map_attr));
4063         map_attr.map_type = BPF_MAP_TYPE_ARRAY;
4064         map_attr.key_size = sizeof(int);
4065         map_attr.value_size = 32;
4066         map_attr.max_entries = 1;
4067
4068         map = bpf_create_map_xattr(&map_attr);
4069         if (map < 0) {
4070                 ret = -errno;
4071                 cp = libbpf_strerror_r(ret, errmsg, sizeof(errmsg));
4072                 pr_warn("Error in %s():%s(%d). Couldn't create simple array map.\n",
4073                         __func__, cp, -ret);
4074                 return ret;
4075         }
4076
4077         insns[0].imm = map;
4078
4079         memset(&prg_attr, 0, sizeof(prg_attr));
4080         prg_attr.prog_type = BPF_PROG_TYPE_SOCKET_FILTER;
4081         prg_attr.insns = insns;
4082         prg_attr.insns_cnt = ARRAY_SIZE(insns);
4083         prg_attr.license = "GPL";
4084
4085         ret = bpf_load_program_xattr(&prg_attr, NULL, 0);
4086         close(map);
4087         return probe_fd(ret);
4088 }
4089
4090 static int probe_kern_btf(void)
4091 {
4092         static const char strs[] = "\0int";
4093         __u32 types[] = {
4094                 /* int */
4095                 BTF_TYPE_INT_ENC(1, BTF_INT_SIGNED, 0, 32, 4),
4096         };
4097
4098         return probe_fd(libbpf__load_raw_btf((char *)types, sizeof(types),
4099                                              strs, sizeof(strs)));
4100 }
4101
4102 static int probe_kern_btf_func(void)
4103 {
4104         static const char strs[] = "\0int\0x\0a";
4105         /* void x(int a) {} */
4106         __u32 types[] = {
4107                 /* int */
4108                 BTF_TYPE_INT_ENC(1, BTF_INT_SIGNED, 0, 32, 4),  /* [1] */
4109                 /* FUNC_PROTO */                                /* [2] */
4110                 BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_FUNC_PROTO, 0, 1), 0),
4111                 BTF_PARAM_ENC(7, 1),
4112                 /* FUNC x */                                    /* [3] */
4113                 BTF_TYPE_ENC(5, BTF_INFO_ENC(BTF_KIND_FUNC, 0, 0), 2),
4114         };
4115
4116         return probe_fd(libbpf__load_raw_btf((char *)types, sizeof(types),
4117                                              strs, sizeof(strs)));
4118 }
4119
4120 static int probe_kern_btf_func_global(void)
4121 {
4122         static const char strs[] = "\0int\0x\0a";
4123         /* static void x(int a) {} */
4124         __u32 types[] = {
4125                 /* int */
4126                 BTF_TYPE_INT_ENC(1, BTF_INT_SIGNED, 0, 32, 4),  /* [1] */
4127                 /* FUNC_PROTO */                                /* [2] */
4128                 BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_FUNC_PROTO, 0, 1), 0),
4129                 BTF_PARAM_ENC(7, 1),
4130                 /* FUNC x BTF_FUNC_GLOBAL */                    /* [3] */
4131                 BTF_TYPE_ENC(5, BTF_INFO_ENC(BTF_KIND_FUNC, 0, BTF_FUNC_GLOBAL), 2),
4132         };
4133
4134         return probe_fd(libbpf__load_raw_btf((char *)types, sizeof(types),
4135                                              strs, sizeof(strs)));
4136 }
4137
4138 static int probe_kern_btf_datasec(void)
4139 {
4140         static const char strs[] = "\0x\0.data";
4141         /* static int a; */
4142         __u32 types[] = {
4143                 /* int */
4144                 BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4),  /* [1] */
4145                 /* VAR x */                                     /* [2] */
4146                 BTF_TYPE_ENC(1, BTF_INFO_ENC(BTF_KIND_VAR, 0, 0), 1),
4147                 BTF_VAR_STATIC,
4148                 /* DATASEC val */                               /* [3] */
4149                 BTF_TYPE_ENC(3, BTF_INFO_ENC(BTF_KIND_DATASEC, 0, 1), 4),
4150                 BTF_VAR_SECINFO_ENC(2, 0, 4),
4151         };
4152
4153         return probe_fd(libbpf__load_raw_btf((char *)types, sizeof(types),
4154                                              strs, sizeof(strs)));
4155 }
4156
4157 static int probe_kern_btf_float(void)
4158 {
4159         static const char strs[] = "\0float";
4160         __u32 types[] = {
4161                 /* float */
4162                 BTF_TYPE_FLOAT_ENC(1, 4),
4163         };
4164
4165         return probe_fd(libbpf__load_raw_btf((char *)types, sizeof(types),
4166                                              strs, sizeof(strs)));
4167 }
4168
4169 static int probe_kern_array_mmap(void)
4170 {
4171         struct bpf_create_map_attr attr = {
4172                 .map_type = BPF_MAP_TYPE_ARRAY,
4173                 .map_flags = BPF_F_MMAPABLE,
4174                 .key_size = sizeof(int),
4175                 .value_size = sizeof(int),
4176                 .max_entries = 1,
4177         };
4178
4179         return probe_fd(bpf_create_map_xattr(&attr));
4180 }
4181
4182 static int probe_kern_exp_attach_type(void)
4183 {
4184         struct bpf_load_program_attr attr;
4185         struct bpf_insn insns[] = {
4186                 BPF_MOV64_IMM(BPF_REG_0, 0),
4187                 BPF_EXIT_INSN(),
4188         };
4189
4190         memset(&attr, 0, sizeof(attr));
4191         /* use any valid combination of program type and (optional)
4192          * non-zero expected attach type (i.e., not a BPF_CGROUP_INET_INGRESS)
4193          * to see if kernel supports expected_attach_type field for
4194          * BPF_PROG_LOAD command
4195          */
4196         attr.prog_type = BPF_PROG_TYPE_CGROUP_SOCK;
4197         attr.expected_attach_type = BPF_CGROUP_INET_SOCK_CREATE;
4198         attr.insns = insns;
4199         attr.insns_cnt = ARRAY_SIZE(insns);
4200         attr.license = "GPL";
4201
4202         return probe_fd(bpf_load_program_xattr(&attr, NULL, 0));
4203 }
4204
4205 static int probe_kern_probe_read_kernel(void)
4206 {
4207         struct bpf_load_program_attr attr;
4208         struct bpf_insn insns[] = {
4209                 BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),   /* r1 = r10 (fp) */
4210                 BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),  /* r1 += -8 */
4211                 BPF_MOV64_IMM(BPF_REG_2, 8),            /* r2 = 8 */
4212                 BPF_MOV64_IMM(BPF_REG_3, 0),            /* r3 = 0 */
4213                 BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_probe_read_kernel),
4214                 BPF_EXIT_INSN(),
4215         };
4216
4217         memset(&attr, 0, sizeof(attr));
4218         attr.prog_type = BPF_PROG_TYPE_KPROBE;
4219         attr.insns = insns;
4220         attr.insns_cnt = ARRAY_SIZE(insns);
4221         attr.license = "GPL";
4222
4223         return probe_fd(bpf_load_program_xattr(&attr, NULL, 0));
4224 }
4225
4226 static int probe_prog_bind_map(void)
4227 {
4228         struct bpf_load_program_attr prg_attr;
4229         struct bpf_create_map_attr map_attr;
4230         char *cp, errmsg[STRERR_BUFSIZE];
4231         struct bpf_insn insns[] = {
4232                 BPF_MOV64_IMM(BPF_REG_0, 0),
4233                 BPF_EXIT_INSN(),
4234         };
4235         int ret, map, prog;
4236
4237         memset(&map_attr, 0, sizeof(map_attr));
4238         map_attr.map_type = BPF_MAP_TYPE_ARRAY;
4239         map_attr.key_size = sizeof(int);
4240         map_attr.value_size = 32;
4241         map_attr.max_entries = 1;
4242
4243         map = bpf_create_map_xattr(&map_attr);
4244         if (map < 0) {
4245                 ret = -errno;
4246                 cp = libbpf_strerror_r(ret, errmsg, sizeof(errmsg));
4247                 pr_warn("Error in %s():%s(%d). Couldn't create simple array map.\n",
4248                         __func__, cp, -ret);
4249                 return ret;
4250         }
4251
4252         memset(&prg_attr, 0, sizeof(prg_attr));
4253         prg_attr.prog_type = BPF_PROG_TYPE_SOCKET_FILTER;
4254         prg_attr.insns = insns;
4255         prg_attr.insns_cnt = ARRAY_SIZE(insns);
4256         prg_attr.license = "GPL";
4257
4258         prog = bpf_load_program_xattr(&prg_attr, NULL, 0);
4259         if (prog < 0) {
4260                 close(map);
4261                 return 0;
4262         }
4263
4264         ret = bpf_prog_bind_map(prog, map, NULL);
4265
4266         close(map);
4267         close(prog);
4268
4269         return ret >= 0;
4270 }
4271
4272 static int probe_module_btf(void)
4273 {
4274         static const char strs[] = "\0int";
4275         __u32 types[] = {
4276                 /* int */
4277                 BTF_TYPE_INT_ENC(1, BTF_INT_SIGNED, 0, 32, 4),
4278         };
4279         struct bpf_btf_info info;
4280         __u32 len = sizeof(info);
4281         char name[16];
4282         int fd, err;
4283
4284         fd = libbpf__load_raw_btf((char *)types, sizeof(types), strs, sizeof(strs));
4285         if (fd < 0)
4286                 return 0; /* BTF not supported at all */
4287
4288         memset(&info, 0, sizeof(info));
4289         info.name = ptr_to_u64(name);
4290         info.name_len = sizeof(name);
4291
4292         /* check that BPF_OBJ_GET_INFO_BY_FD supports specifying name pointer;
4293          * kernel's module BTF support coincides with support for
4294          * name/name_len fields in struct bpf_btf_info.
4295          */
4296         err = bpf_obj_get_info_by_fd(fd, &info, &len);
4297         close(fd);
4298         return !err;
4299 }
4300
4301 enum kern_feature_result {
4302         FEAT_UNKNOWN = 0,
4303         FEAT_SUPPORTED = 1,
4304         FEAT_MISSING = 2,
4305 };
4306
4307 typedef int (*feature_probe_fn)(void);
4308
4309 static struct kern_feature_desc {
4310         const char *desc;
4311         feature_probe_fn probe;
4312         enum kern_feature_result res;
4313 } feature_probes[__FEAT_CNT] = {
4314         [FEAT_PROG_NAME] = {
4315                 "BPF program name", probe_kern_prog_name,
4316         },
4317         [FEAT_GLOBAL_DATA] = {
4318                 "global variables", probe_kern_global_data,
4319         },
4320         [FEAT_BTF] = {
4321                 "minimal BTF", probe_kern_btf,
4322         },
4323         [FEAT_BTF_FUNC] = {
4324                 "BTF functions", probe_kern_btf_func,
4325         },
4326         [FEAT_BTF_GLOBAL_FUNC] = {
4327                 "BTF global function", probe_kern_btf_func_global,
4328         },
4329         [FEAT_BTF_DATASEC] = {
4330                 "BTF data section and variable", probe_kern_btf_datasec,
4331         },
4332         [FEAT_ARRAY_MMAP] = {
4333                 "ARRAY map mmap()", probe_kern_array_mmap,
4334         },
4335         [FEAT_EXP_ATTACH_TYPE] = {
4336                 "BPF_PROG_LOAD expected_attach_type attribute",
4337                 probe_kern_exp_attach_type,
4338         },
4339         [FEAT_PROBE_READ_KERN] = {
4340                 "bpf_probe_read_kernel() helper", probe_kern_probe_read_kernel,
4341         },
4342         [FEAT_PROG_BIND_MAP] = {
4343                 "BPF_PROG_BIND_MAP support", probe_prog_bind_map,
4344         },
4345         [FEAT_MODULE_BTF] = {
4346                 "module BTF support", probe_module_btf,
4347         },
4348         [FEAT_BTF_FLOAT] = {
4349                 "BTF_KIND_FLOAT support", probe_kern_btf_float,
4350         },
4351 };
4352
4353 static bool kernel_supports(const struct bpf_object *obj, enum kern_feature_id feat_id)
4354 {
4355         struct kern_feature_desc *feat = &feature_probes[feat_id];
4356         int ret;
4357
4358         if (obj->gen_loader)
4359                 /* To generate loader program assume the latest kernel
4360                  * to avoid doing extra prog_load, map_create syscalls.
4361                  */
4362                 return true;
4363
4364         if (READ_ONCE(feat->res) == FEAT_UNKNOWN) {
4365                 ret = feat->probe();
4366                 if (ret > 0) {
4367                         WRITE_ONCE(feat->res, FEAT_SUPPORTED);
4368                 } else if (ret == 0) {
4369                         WRITE_ONCE(feat->res, FEAT_MISSING);
4370                 } else {
4371                         pr_warn("Detection of kernel %s support failed: %d\n", feat->desc, ret);
4372                         WRITE_ONCE(feat->res, FEAT_MISSING);
4373                 }
4374         }
4375
4376         return READ_ONCE(feat->res) == FEAT_SUPPORTED;
4377 }
4378
4379 static bool map_is_reuse_compat(const struct bpf_map *map, int map_fd)
4380 {
4381         struct bpf_map_info map_info = {};
4382         char msg[STRERR_BUFSIZE];
4383         __u32 map_info_len;
4384
4385         map_info_len = sizeof(map_info);
4386
4387         if (bpf_obj_get_info_by_fd(map_fd, &map_info, &map_info_len)) {
4388                 pr_warn("failed to get map info for map FD %d: %s\n",
4389                         map_fd, libbpf_strerror_r(errno, msg, sizeof(msg)));
4390                 return false;
4391         }
4392
4393         return (map_info.type == map->def.type &&
4394                 map_info.key_size == map->def.key_size &&
4395                 map_info.value_size == map->def.value_size &&
4396                 map_info.max_entries == map->def.max_entries &&
4397                 map_info.map_flags == map->def.map_flags);
4398 }
4399
4400 static int
4401 bpf_object__reuse_map(struct bpf_map *map)
4402 {
4403         char *cp, errmsg[STRERR_BUFSIZE];
4404         int err, pin_fd;
4405
4406         pin_fd = bpf_obj_get(map->pin_path);
4407         if (pin_fd < 0) {
4408                 err = -errno;
4409                 if (err == -ENOENT) {
4410                         pr_debug("found no pinned map to reuse at '%s'\n",
4411                                  map->pin_path);
4412                         return 0;
4413                 }
4414
4415                 cp = libbpf_strerror_r(-err, errmsg, sizeof(errmsg));
4416                 pr_warn("couldn't retrieve pinned map '%s': %s\n",
4417                         map->pin_path, cp);
4418                 return err;
4419         }
4420
4421         if (!map_is_reuse_compat(map, pin_fd)) {
4422                 pr_warn("couldn't reuse pinned map at '%s': parameter mismatch\n",
4423                         map->pin_path);
4424                 close(pin_fd);
4425                 return -EINVAL;
4426         }
4427
4428         err = bpf_map__reuse_fd(map, pin_fd);
4429         if (err) {
4430                 close(pin_fd);
4431                 return err;
4432         }
4433         map->pinned = true;
4434         pr_debug("reused pinned map at '%s'\n", map->pin_path);
4435
4436         return 0;
4437 }
4438
4439 static int
4440 bpf_object__populate_internal_map(struct bpf_object *obj, struct bpf_map *map)
4441 {
4442         enum libbpf_map_type map_type = map->libbpf_type;
4443         char *cp, errmsg[STRERR_BUFSIZE];
4444         int err, zero = 0;
4445
4446         if (obj->gen_loader) {
4447                 bpf_gen__map_update_elem(obj->gen_loader, map - obj->maps,
4448                                          map->mmaped, map->def.value_size);
4449                 if (map_type == LIBBPF_MAP_RODATA || map_type == LIBBPF_MAP_KCONFIG)
4450                         bpf_gen__map_freeze(obj->gen_loader, map - obj->maps);
4451                 return 0;
4452         }
4453         err = bpf_map_update_elem(map->fd, &zero, map->mmaped, 0);
4454         if (err) {
4455                 err = -errno;
4456                 cp = libbpf_strerror_r(err, errmsg, sizeof(errmsg));
4457                 pr_warn("Error setting initial map(%s) contents: %s\n",
4458                         map->name, cp);
4459                 return err;
4460         }
4461
4462         /* Freeze .rodata and .kconfig map as read-only from syscall side. */
4463         if (map_type == LIBBPF_MAP_RODATA || map_type == LIBBPF_MAP_KCONFIG) {
4464                 err = bpf_map_freeze(map->fd);
4465                 if (err) {
4466                         err = -errno;
4467                         cp = libbpf_strerror_r(err, errmsg, sizeof(errmsg));
4468                         pr_warn("Error freezing map(%s) as read-only: %s\n",
4469                                 map->name, cp);
4470                         return err;
4471                 }
4472         }
4473         return 0;
4474 }
4475
4476 static void bpf_map__destroy(struct bpf_map *map);
4477
4478 static int bpf_object__create_map(struct bpf_object *obj, struct bpf_map *map, bool is_inner)
4479 {
4480         struct bpf_create_map_attr create_attr;
4481         struct bpf_map_def *def = &map->def;
4482
4483         memset(&create_attr, 0, sizeof(create_attr));
4484
4485         if (kernel_supports(obj, FEAT_PROG_NAME))
4486                 create_attr.name = map->name;
4487         create_attr.map_ifindex = map->map_ifindex;
4488         create_attr.map_type = def->type;
4489         create_attr.map_flags = def->map_flags;
4490         create_attr.key_size = def->key_size;
4491         create_attr.value_size = def->value_size;
4492         create_attr.numa_node = map->numa_node;
4493
4494         if (def->type == BPF_MAP_TYPE_PERF_EVENT_ARRAY && !def->max_entries) {
4495                 int nr_cpus;
4496
4497                 nr_cpus = libbpf_num_possible_cpus();
4498                 if (nr_cpus < 0) {
4499                         pr_warn("map '%s': failed to determine number of system CPUs: %d\n",
4500                                 map->name, nr_cpus);
4501                         return nr_cpus;
4502                 }
4503                 pr_debug("map '%s': setting size to %d\n", map->name, nr_cpus);
4504                 create_attr.max_entries = nr_cpus;
4505         } else {
4506                 create_attr.max_entries = def->max_entries;
4507         }
4508
4509         if (bpf_map__is_struct_ops(map))
4510                 create_attr.btf_vmlinux_value_type_id =
4511                         map->btf_vmlinux_value_type_id;
4512
4513         create_attr.btf_fd = 0;
4514         create_attr.btf_key_type_id = 0;
4515         create_attr.btf_value_type_id = 0;
4516         if (obj->btf && btf__fd(obj->btf) >= 0 && !bpf_map_find_btf_info(obj, map)) {
4517                 create_attr.btf_fd = btf__fd(obj->btf);
4518                 create_attr.btf_key_type_id = map->btf_key_type_id;
4519                 create_attr.btf_value_type_id = map->btf_value_type_id;
4520         }
4521
4522         if (bpf_map_type__is_map_in_map(def->type)) {
4523                 if (map->inner_map) {
4524                         int err;
4525
4526                         err = bpf_object__create_map(obj, map->inner_map, true);
4527                         if (err) {
4528                                 pr_warn("map '%s': failed to create inner map: %d\n",
4529                                         map->name, err);
4530                                 return err;
4531                         }
4532                         map->inner_map_fd = bpf_map__fd(map->inner_map);
4533                 }
4534                 if (map->inner_map_fd >= 0)
4535                         create_attr.inner_map_fd = map->inner_map_fd;
4536         }
4537
4538         if (obj->gen_loader) {
4539                 bpf_gen__map_create(obj->gen_loader, &create_attr, is_inner ? -1 : map - obj->maps);
4540                 /* Pretend to have valid FD to pass various fd >= 0 checks.
4541                  * This fd == 0 will not be used with any syscall and will be reset to -1 eventually.
4542                  */
4543                 map->fd = 0;
4544         } else {
4545                 map->fd = bpf_create_map_xattr(&create_attr);
4546         }
4547         if (map->fd < 0 && (create_attr.btf_key_type_id ||
4548                             create_attr.btf_value_type_id)) {
4549                 char *cp, errmsg[STRERR_BUFSIZE];
4550                 int err = -errno;
4551
4552                 cp = libbpf_strerror_r(err, errmsg, sizeof(errmsg));
4553                 pr_warn("Error in bpf_create_map_xattr(%s):%s(%d). Retrying without BTF.\n",
4554                         map->name, cp, err);
4555                 create_attr.btf_fd = 0;
4556                 create_attr.btf_key_type_id = 0;
4557                 create_attr.btf_value_type_id = 0;
4558                 map->btf_key_type_id = 0;
4559                 map->btf_value_type_id = 0;
4560                 map->fd = bpf_create_map_xattr(&create_attr);
4561         }
4562
4563         if (map->fd < 0)
4564                 return -errno;
4565
4566         if (bpf_map_type__is_map_in_map(def->type) && map->inner_map) {
4567                 if (obj->gen_loader)
4568                         map->inner_map->fd = -1;
4569                 bpf_map__destroy(map->inner_map);
4570                 zfree(&map->inner_map);
4571         }
4572
4573         return 0;
4574 }
4575
4576 static int init_map_slots(struct bpf_object *obj, struct bpf_map *map)
4577 {
4578         const struct bpf_map *targ_map;
4579         unsigned int i;
4580         int fd, err = 0;
4581
4582         for (i = 0; i < map->init_slots_sz; i++) {
4583                 if (!map->init_slots[i])
4584                         continue;
4585
4586                 targ_map = map->init_slots[i];
4587                 fd = bpf_map__fd(targ_map);
4588                 if (obj->gen_loader) {
4589                         pr_warn("// TODO map_update_elem: idx %td key %d value==map_idx %td\n",
4590                                 map - obj->maps, i, targ_map - obj->maps);
4591                         return -ENOTSUP;
4592                 } else {
4593                         err = bpf_map_update_elem(map->fd, &i, &fd, 0);
4594                 }
4595                 if (err) {
4596                         err = -errno;
4597                         pr_warn("map '%s': failed to initialize slot [%d] to map '%s' fd=%d: %d\n",
4598                                 map->name, i, targ_map->name,
4599                                 fd, err);
4600                         return err;
4601                 }
4602                 pr_debug("map '%s': slot [%d] set to map '%s' fd=%d\n",
4603                          map->name, i, targ_map->name, fd);
4604         }
4605
4606         zfree(&map->init_slots);
4607         map->init_slots_sz = 0;
4608
4609         return 0;
4610 }
4611
4612 static int
4613 bpf_object__create_maps(struct bpf_object *obj)
4614 {
4615         struct bpf_map *map;
4616         char *cp, errmsg[STRERR_BUFSIZE];
4617         unsigned int i, j;
4618         int err;
4619
4620         for (i = 0; i < obj->nr_maps; i++) {
4621                 map = &obj->maps[i];
4622
4623                 if (map->pin_path) {
4624                         err = bpf_object__reuse_map(map);
4625                         if (err) {
4626                                 pr_warn("map '%s': error reusing pinned map\n",
4627                                         map->name);
4628                                 goto err_out;
4629                         }
4630                 }
4631
4632                 if (map->fd >= 0) {
4633                         pr_debug("map '%s': skipping creation (preset fd=%d)\n",
4634                                  map->name, map->fd);
4635                 } else {
4636                         err = bpf_object__create_map(obj, map, false);
4637                         if (err)
4638                                 goto err_out;
4639
4640                         pr_debug("map '%s': created successfully, fd=%d\n",
4641                                  map->name, map->fd);
4642
4643                         if (bpf_map__is_internal(map)) {
4644                                 err = bpf_object__populate_internal_map(obj, map);
4645                                 if (err < 0) {
4646                                         zclose(map->fd);
4647                                         goto err_out;
4648                                 }
4649                         }
4650
4651                         if (map->init_slots_sz) {
4652                                 err = init_map_slots(obj, map);
4653                                 if (err < 0) {
4654                                         zclose(map->fd);
4655                                         goto err_out;
4656                                 }
4657                         }
4658                 }
4659
4660                 if (map->pin_path && !map->pinned) {
4661                         err = bpf_map__pin(map, NULL);
4662                         if (err) {
4663                                 pr_warn("map '%s': failed to auto-pin at '%s': %d\n",
4664                                         map->name, map->pin_path, err);
4665                                 zclose(map->fd);
4666                                 goto err_out;
4667                         }
4668                 }
4669         }
4670
4671         return 0;
4672
4673 err_out:
4674         cp = libbpf_strerror_r(err, errmsg, sizeof(errmsg));
4675         pr_warn("map '%s': failed to create: %s(%d)\n", map->name, cp, err);
4676         pr_perm_msg(err);
4677         for (j = 0; j < i; j++)
4678                 zclose(obj->maps[j].fd);
4679         return err;
4680 }
4681
4682 #define BPF_CORE_SPEC_MAX_LEN 64
4683
4684 /* represents BPF CO-RE field or array element accessor */
4685 struct bpf_core_accessor {
4686         __u32 type_id;          /* struct/union type or array element type */
4687         __u32 idx;              /* field index or array index */
4688         const char *name;       /* field name or NULL for array accessor */
4689 };
4690
4691 struct bpf_core_spec {
4692         const struct btf *btf;
4693         /* high-level spec: named fields and array indices only */
4694         struct bpf_core_accessor spec[BPF_CORE_SPEC_MAX_LEN];
4695         /* original unresolved (no skip_mods_or_typedefs) root type ID */
4696         __u32 root_type_id;
4697         /* CO-RE relocation kind */
4698         enum bpf_core_relo_kind relo_kind;
4699         /* high-level spec length */
4700         int len;
4701         /* raw, low-level spec: 1-to-1 with accessor spec string */
4702         int raw_spec[BPF_CORE_SPEC_MAX_LEN];
4703         /* raw spec length */
4704         int raw_len;
4705         /* field bit offset represented by spec */
4706         __u32 bit_offset;
4707 };
4708
4709 static bool str_is_empty(const char *s)
4710 {
4711         return !s || !s[0];
4712 }
4713
4714 static bool is_flex_arr(const struct btf *btf,
4715                         const struct bpf_core_accessor *acc,
4716                         const struct btf_array *arr)
4717 {
4718         const struct btf_type *t;
4719
4720         /* not a flexible array, if not inside a struct or has non-zero size */
4721         if (!acc->name || arr->nelems > 0)
4722                 return false;
4723
4724         /* has to be the last member of enclosing struct */
4725         t = btf__type_by_id(btf, acc->type_id);
4726         return acc->idx == btf_vlen(t) - 1;
4727 }
4728
4729 static const char *core_relo_kind_str(enum bpf_core_relo_kind kind)
4730 {
4731         switch (kind) {
4732         case BPF_FIELD_BYTE_OFFSET: return "byte_off";
4733         case BPF_FIELD_BYTE_SIZE: return "byte_sz";
4734         case BPF_FIELD_EXISTS: return "field_exists";
4735         case BPF_FIELD_SIGNED: return "signed";
4736         case BPF_FIELD_LSHIFT_U64: return "lshift_u64";
4737         case BPF_FIELD_RSHIFT_U64: return "rshift_u64";
4738         case BPF_TYPE_ID_LOCAL: return "local_type_id";
4739         case BPF_TYPE_ID_TARGET: return "target_type_id";
4740         case BPF_TYPE_EXISTS: return "type_exists";
4741         case BPF_TYPE_SIZE: return "type_size";
4742         case BPF_ENUMVAL_EXISTS: return "enumval_exists";
4743         case BPF_ENUMVAL_VALUE: return "enumval_value";
4744         default: return "unknown";
4745         }
4746 }
4747
4748 static bool core_relo_is_field_based(enum bpf_core_relo_kind kind)
4749 {
4750         switch (kind) {
4751         case BPF_FIELD_BYTE_OFFSET:
4752         case BPF_FIELD_BYTE_SIZE:
4753         case BPF_FIELD_EXISTS:
4754         case BPF_FIELD_SIGNED:
4755         case BPF_FIELD_LSHIFT_U64:
4756         case BPF_FIELD_RSHIFT_U64:
4757                 return true;
4758         default:
4759                 return false;
4760         }
4761 }
4762
4763 static bool core_relo_is_type_based(enum bpf_core_relo_kind kind)
4764 {
4765         switch (kind) {
4766         case BPF_TYPE_ID_LOCAL:
4767         case BPF_TYPE_ID_TARGET:
4768         case BPF_TYPE_EXISTS:
4769         case BPF_TYPE_SIZE:
4770                 return true;
4771         default:
4772                 return false;
4773         }
4774 }
4775
4776 static bool core_relo_is_enumval_based(enum bpf_core_relo_kind kind)
4777 {
4778         switch (kind) {
4779         case BPF_ENUMVAL_EXISTS:
4780         case BPF_ENUMVAL_VALUE:
4781                 return true;
4782         default:
4783                 return false;
4784         }
4785 }
4786
4787 /*
4788  * Turn bpf_core_relo into a low- and high-level spec representation,
4789  * validating correctness along the way, as well as calculating resulting
4790  * field bit offset, specified by accessor string. Low-level spec captures
4791  * every single level of nestedness, including traversing anonymous
4792  * struct/union members. High-level one only captures semantically meaningful
4793  * "turning points": named fields and array indicies.
4794  * E.g., for this case:
4795  *
4796  *   struct sample {
4797  *       int __unimportant;
4798  *       struct {
4799  *           int __1;
4800  *           int __2;
4801  *           int a[7];
4802  *       };
4803  *   };
4804  *
4805  *   struct sample *s = ...;
4806  *
4807  *   int x = &s->a[3]; // access string = '0:1:2:3'
4808  *
4809  * Low-level spec has 1:1 mapping with each element of access string (it's
4810  * just a parsed access string representation): [0, 1, 2, 3].
4811  *
4812  * High-level spec will capture only 3 points:
4813  *   - intial zero-index access by pointer (&s->... is the same as &s[0]...);
4814  *   - field 'a' access (corresponds to '2' in low-level spec);
4815  *   - array element #3 access (corresponds to '3' in low-level spec).
4816  *
4817  * Type-based relocations (TYPE_EXISTS/TYPE_SIZE,
4818  * TYPE_ID_LOCAL/TYPE_ID_TARGET) don't capture any field information. Their
4819  * spec and raw_spec are kept empty.
4820  *
4821  * Enum value-based relocations (ENUMVAL_EXISTS/ENUMVAL_VALUE) use access
4822  * string to specify enumerator's value index that need to be relocated.
4823  */
4824 static int bpf_core_parse_spec(const struct btf *btf,
4825                                __u32 type_id,
4826                                const char *spec_str,
4827                                enum bpf_core_relo_kind relo_kind,
4828                                struct bpf_core_spec *spec)
4829 {
4830         int access_idx, parsed_len, i;
4831         struct bpf_core_accessor *acc;
4832         const struct btf_type *t;
4833         const char *name;
4834         __u32 id;
4835         __s64 sz;
4836
4837         if (str_is_empty(spec_str) || *spec_str == ':')
4838                 return -EINVAL;
4839
4840         memset(spec, 0, sizeof(*spec));
4841         spec->btf = btf;
4842         spec->root_type_id = type_id;
4843         spec->relo_kind = relo_kind;
4844
4845         /* type-based relocations don't have a field access string */
4846         if (core_relo_is_type_based(relo_kind)) {
4847                 if (strcmp(spec_str, "0"))
4848                         return -EINVAL;
4849                 return 0;
4850         }
4851
4852         /* parse spec_str="0:1:2:3:4" into array raw_spec=[0, 1, 2, 3, 4] */
4853         while (*spec_str) {
4854                 if (*spec_str == ':')
4855                         ++spec_str;
4856                 if (sscanf(spec_str, "%d%n", &access_idx, &parsed_len) != 1)
4857                         return -EINVAL;
4858                 if (spec->raw_len == BPF_CORE_SPEC_MAX_LEN)
4859                         return -E2BIG;
4860                 spec_str += parsed_len;
4861                 spec->raw_spec[spec->raw_len++] = access_idx;
4862         }
4863
4864         if (spec->raw_len == 0)
4865                 return -EINVAL;
4866
4867         t = skip_mods_and_typedefs(btf, type_id, &id);
4868         if (!t)
4869                 return -EINVAL;
4870
4871         access_idx = spec->raw_spec[0];
4872         acc = &spec->spec[0];
4873         acc->type_id = id;
4874         acc->idx = access_idx;
4875         spec->len++;
4876
4877         if (core_relo_is_enumval_based(relo_kind)) {
4878                 if (!btf_is_enum(t) || spec->raw_len > 1 || access_idx >= btf_vlen(t))
4879                         return -EINVAL;
4880
4881                 /* record enumerator name in a first accessor */
4882                 acc->name = btf__name_by_offset(btf, btf_enum(t)[access_idx].name_off);
4883                 return 0;
4884         }
4885
4886         if (!core_relo_is_field_based(relo_kind))
4887                 return -EINVAL;
4888
4889         sz = btf__resolve_size(btf, id);
4890         if (sz < 0)
4891                 return sz;
4892         spec->bit_offset = access_idx * sz * 8;
4893
4894         for (i = 1; i < spec->raw_len; i++) {
4895                 t = skip_mods_and_typedefs(btf, id, &id);
4896                 if (!t)
4897                         return -EINVAL;
4898
4899                 access_idx = spec->raw_spec[i];
4900                 acc = &spec->spec[spec->len];
4901
4902                 if (btf_is_composite(t)) {
4903                         const struct btf_member *m;
4904                         __u32 bit_offset;
4905
4906                         if (access_idx >= btf_vlen(t))
4907                                 return -EINVAL;
4908
4909                         bit_offset = btf_member_bit_offset(t, access_idx);
4910                         spec->bit_offset += bit_offset;
4911
4912                         m = btf_members(t) + access_idx;
4913                         if (m->name_off) {
4914                                 name = btf__name_by_offset(btf, m->name_off);
4915                                 if (str_is_empty(name))
4916                                         return -EINVAL;
4917
4918                                 acc->type_id = id;
4919                                 acc->idx = access_idx;
4920                                 acc->name = name;
4921                                 spec->len++;
4922                         }
4923
4924                         id = m->type;
4925                 } else if (btf_is_array(t)) {
4926                         const struct btf_array *a = btf_array(t);
4927                         bool flex;
4928
4929                         t = skip_mods_and_typedefs(btf, a->type, &id);
4930                         if (!t)
4931                                 return -EINVAL;
4932
4933                         flex = is_flex_arr(btf, acc - 1, a);
4934                         if (!flex && access_idx >= a->nelems)
4935                                 return -EINVAL;
4936
4937                         spec->spec[spec->len].type_id = id;
4938                         spec->spec[spec->len].idx = access_idx;
4939                         spec->len++;
4940
4941                         sz = btf__resolve_size(btf, id);
4942                         if (sz < 0)
4943                                 return sz;
4944                         spec->bit_offset += access_idx * sz * 8;
4945                 } else {
4946                         pr_warn("relo for [%u] %s (at idx %d) captures type [%d] of unexpected kind %s\n",
4947                                 type_id, spec_str, i, id, btf_kind_str(t));
4948                         return -EINVAL;
4949                 }
4950         }
4951
4952         return 0;
4953 }
4954
4955 static bool bpf_core_is_flavor_sep(const char *s)
4956 {
4957         /* check X___Y name pattern, where X and Y are not underscores */
4958         return s[0] != '_' &&                                 /* X */
4959                s[1] == '_' && s[2] == '_' && s[3] == '_' &&   /* ___ */
4960                s[4] != '_';                                   /* Y */
4961 }
4962
4963 /* Given 'some_struct_name___with_flavor' return the length of a name prefix
4964  * before last triple underscore. Struct name part after last triple
4965  * underscore is ignored by BPF CO-RE relocation during relocation matching.
4966  */
4967 static size_t bpf_core_essential_name_len(const char *name)
4968 {
4969         size_t n = strlen(name);
4970         int i;
4971
4972         for (i = n - 5; i >= 0; i--) {
4973                 if (bpf_core_is_flavor_sep(name + i))
4974                         return i + 1;
4975         }
4976         return n;
4977 }
4978
4979 struct core_cand
4980 {
4981         const struct btf *btf;
4982         const struct btf_type *t;
4983         const char *name;
4984         __u32 id;
4985 };
4986
4987 /* dynamically sized list of type IDs and its associated struct btf */
4988 struct core_cand_list {
4989         struct core_cand *cands;
4990         int len;
4991 };
4992
4993 static void bpf_core_free_cands(struct core_cand_list *cands)
4994 {
4995         free(cands->cands);
4996         free(cands);
4997 }
4998
4999 static int bpf_core_add_cands(struct core_cand *local_cand,
5000                               size_t local_essent_len,
5001                               const struct btf *targ_btf,
5002                               const char *targ_btf_name,
5003                               int targ_start_id,
5004                               struct core_cand_list *cands)
5005 {
5006         struct core_cand *new_cands, *cand;
5007         const struct btf_type *t;
5008         const char *targ_name;
5009         size_t targ_essent_len;
5010         int n, i;
5011
5012         n = btf__get_nr_types(targ_btf);
5013         for (i = targ_start_id; i <= n; i++) {
5014                 t = btf__type_by_id(targ_btf, i);
5015                 if (btf_kind(t) != btf_kind(local_cand->t))
5016                         continue;
5017
5018                 targ_name = btf__name_by_offset(targ_btf, t->name_off);
5019                 if (str_is_empty(targ_name))
5020                         continue;
5021
5022                 targ_essent_len = bpf_core_essential_name_len(targ_name);
5023                 if (targ_essent_len != local_essent_len)
5024                         continue;
5025
5026                 if (strncmp(local_cand->name, targ_name, local_essent_len) != 0)
5027                         continue;
5028
5029                 pr_debug("CO-RE relocating [%d] %s %s: found target candidate [%d] %s %s in [%s]\n",
5030                          local_cand->id, btf_kind_str(local_cand->t),
5031                          local_cand->name, i, btf_kind_str(t), targ_name,
5032                          targ_btf_name);
5033                 new_cands = libbpf_reallocarray(cands->cands, cands->len + 1,
5034                                               sizeof(*cands->cands));
5035                 if (!new_cands)
5036                         return -ENOMEM;
5037
5038                 cand = &new_cands[cands->len];
5039                 cand->btf = targ_btf;
5040                 cand->t = t;
5041                 cand->name = targ_name;
5042                 cand->id = i;
5043
5044                 cands->cands = new_cands;
5045                 cands->len++;
5046         }
5047         return 0;
5048 }
5049
5050 static int load_module_btfs(struct bpf_object *obj)
5051 {
5052         struct bpf_btf_info info;
5053         struct module_btf *mod_btf;
5054         struct btf *btf;
5055         char name[64];
5056         __u32 id = 0, len;
5057         int err, fd;
5058
5059         if (obj->btf_modules_loaded)
5060                 return 0;
5061
5062         if (obj->gen_loader)
5063                 return 0;
5064
5065         /* don't do this again, even if we find no module BTFs */
5066         obj->btf_modules_loaded = true;
5067
5068         /* kernel too old to support module BTFs */
5069         if (!kernel_supports(obj, FEAT_MODULE_BTF))
5070                 return 0;
5071
5072         while (true) {
5073                 err = bpf_btf_get_next_id(id, &id);
5074                 if (err && errno == ENOENT)
5075                         return 0;
5076                 if (err) {
5077                         err = -errno;
5078                         pr_warn("failed to iterate BTF objects: %d\n", err);
5079                         return err;
5080                 }
5081
5082                 fd = bpf_btf_get_fd_by_id(id);
5083                 if (fd < 0) {
5084                         if (errno == ENOENT)
5085                                 continue; /* expected race: BTF was unloaded */
5086                         err = -errno;
5087                         pr_warn("failed to get BTF object #%d FD: %d\n", id, err);
5088                         return err;
5089                 }
5090
5091                 len = sizeof(info);
5092                 memset(&info, 0, sizeof(info));
5093                 info.name = ptr_to_u64(name);
5094                 info.name_len = sizeof(name);
5095
5096                 err = bpf_obj_get_info_by_fd(fd, &info, &len);
5097                 if (err) {
5098                         err = -errno;
5099                         pr_warn("failed to get BTF object #%d info: %d\n", id, err);
5100                         goto err_out;
5101                 }
5102
5103                 /* ignore non-module BTFs */
5104                 if (!info.kernel_btf || strcmp(name, "vmlinux") == 0) {
5105                         close(fd);
5106                         continue;
5107                 }
5108
5109                 btf = btf_get_from_fd(fd, obj->btf_vmlinux);
5110                 err = libbpf_get_error(btf);
5111                 if (err) {
5112                         pr_warn("failed to load module [%s]'s BTF object #%d: %d\n",
5113                                 name, id, err);
5114                         goto err_out;
5115                 }
5116
5117                 err = libbpf_ensure_mem((void **)&obj->btf_modules, &obj->btf_module_cap,
5118                                         sizeof(*obj->btf_modules), obj->btf_module_cnt + 1);
5119                 if (err)
5120                         goto err_out;
5121
5122                 mod_btf = &obj->btf_modules[obj->btf_module_cnt++];
5123
5124                 mod_btf->btf = btf;
5125                 mod_btf->id = id;
5126                 mod_btf->fd = fd;
5127                 mod_btf->name = strdup(name);
5128                 if (!mod_btf->name) {
5129                         err = -ENOMEM;
5130                         goto err_out;
5131                 }
5132                 continue;
5133
5134 err_out:
5135                 close(fd);
5136                 return err;
5137         }
5138
5139         return 0;
5140 }
5141
5142 static struct core_cand_list *
5143 bpf_core_find_cands(struct bpf_object *obj, const struct btf *local_btf, __u32 local_type_id)
5144 {
5145         struct core_cand local_cand = {};
5146         struct core_cand_list *cands;
5147         const struct btf *main_btf;
5148         size_t local_essent_len;
5149         int err, i;
5150
5151         local_cand.btf = local_btf;
5152         local_cand.t = btf__type_by_id(local_btf, local_type_id);
5153         if (!local_cand.t)
5154                 return ERR_PTR(-EINVAL);
5155
5156         local_cand.name = btf__name_by_offset(local_btf, local_cand.t->name_off);
5157         if (str_is_empty(local_cand.name))
5158                 return ERR_PTR(-EINVAL);
5159         local_essent_len = bpf_core_essential_name_len(local_cand.name);
5160
5161         cands = calloc(1, sizeof(*cands));
5162         if (!cands)
5163                 return ERR_PTR(-ENOMEM);
5164
5165         /* Attempt to find target candidates in vmlinux BTF first */
5166         main_btf = obj->btf_vmlinux_override ?: obj->btf_vmlinux;
5167         err = bpf_core_add_cands(&local_cand, local_essent_len, main_btf, "vmlinux", 1, cands);
5168         if (err)
5169                 goto err_out;
5170
5171         /* if vmlinux BTF has any candidate, don't got for module BTFs */
5172         if (cands->len)
5173                 return cands;
5174
5175         /* if vmlinux BTF was overridden, don't attempt to load module BTFs */
5176         if (obj->btf_vmlinux_override)
5177                 return cands;
5178
5179         /* now look through module BTFs, trying to still find candidates */
5180         err = load_module_btfs(obj);
5181         if (err)
5182                 goto err_out;
5183
5184         for (i = 0; i < obj->btf_module_cnt; i++) {
5185                 err = bpf_core_add_cands(&local_cand, local_essent_len,
5186                                          obj->btf_modules[i].btf,
5187                                          obj->btf_modules[i].name,
5188                                          btf__get_nr_types(obj->btf_vmlinux) + 1,
5189                                          cands);
5190                 if (err)
5191                         goto err_out;
5192         }
5193
5194         return cands;
5195 err_out:
5196         bpf_core_free_cands(cands);
5197         return ERR_PTR(err);
5198 }
5199
5200 /* Check two types for compatibility for the purpose of field access
5201  * relocation. const/volatile/restrict and typedefs are skipped to ensure we
5202  * are relocating semantically compatible entities:
5203  *   - any two STRUCTs/UNIONs are compatible and can be mixed;
5204  *   - any two FWDs are compatible, if their names match (modulo flavor suffix);
5205  *   - any two PTRs are always compatible;
5206  *   - for ENUMs, names should be the same (ignoring flavor suffix) or at
5207  *     least one of enums should be anonymous;
5208  *   - for ENUMs, check sizes, names are ignored;
5209  *   - for INT, size and signedness are ignored;
5210  *   - any two FLOATs are always compatible;
5211  *   - for ARRAY, dimensionality is ignored, element types are checked for
5212  *     compatibility recursively;
5213  *   - everything else shouldn't be ever a target of relocation.
5214  * These rules are not set in stone and probably will be adjusted as we get
5215  * more experience with using BPF CO-RE relocations.
5216  */
5217 static int bpf_core_fields_are_compat(const struct btf *local_btf,
5218                                       __u32 local_id,
5219                                       const struct btf *targ_btf,
5220                                       __u32 targ_id)
5221 {
5222         const struct btf_type *local_type, *targ_type;
5223
5224 recur:
5225         local_type = skip_mods_and_typedefs(local_btf, local_id, &local_id);
5226         targ_type = skip_mods_and_typedefs(targ_btf, targ_id, &targ_id);
5227         if (!local_type || !targ_type)
5228                 return -EINVAL;
5229
5230         if (btf_is_composite(local_type) && btf_is_composite(targ_type))
5231                 return 1;
5232         if (btf_kind(local_type) != btf_kind(targ_type))
5233                 return 0;
5234
5235         switch (btf_kind(local_type)) {
5236         case BTF_KIND_PTR:
5237         case BTF_KIND_FLOAT:
5238                 return 1;
5239         case BTF_KIND_FWD:
5240         case BTF_KIND_ENUM: {
5241                 const char *local_name, *targ_name;
5242                 size_t local_len, targ_len;
5243
5244                 local_name = btf__name_by_offset(local_btf,
5245                                                  local_type->name_off);
5246                 targ_name = btf__name_by_offset(targ_btf, targ_type->name_off);
5247                 local_len = bpf_core_essential_name_len(local_name);
5248                 targ_len = bpf_core_essential_name_len(targ_name);
5249                 /* one of them is anonymous or both w/ same flavor-less names */
5250                 return local_len == 0 || targ_len == 0 ||
5251                        (local_len == targ_len &&
5252                         strncmp(local_name, targ_name, local_len) == 0);
5253         }
5254         case BTF_KIND_INT:
5255                 /* just reject deprecated bitfield-like integers; all other
5256                  * integers are by default compatible between each other
5257                  */
5258                 return btf_int_offset(local_type) == 0 &&
5259                        btf_int_offset(targ_type) == 0;
5260         case BTF_KIND_ARRAY:
5261                 local_id = btf_array(local_type)->type;
5262                 targ_id = btf_array(targ_type)->type;
5263                 goto recur;
5264         default:
5265                 pr_warn("unexpected kind %d relocated, local [%d], target [%d]\n",
5266                         btf_kind(local_type), local_id, targ_id);
5267                 return 0;
5268         }
5269 }
5270
5271 /*
5272  * Given single high-level named field accessor in local type, find
5273  * corresponding high-level accessor for a target type. Along the way,
5274  * maintain low-level spec for target as well. Also keep updating target
5275  * bit offset.
5276  *
5277  * Searching is performed through recursive exhaustive enumeration of all
5278  * fields of a struct/union. If there are any anonymous (embedded)
5279  * structs/unions, they are recursively searched as well. If field with
5280  * desired name is found, check compatibility between local and target types,
5281  * before returning result.
5282  *
5283  * 1 is returned, if field is found.
5284  * 0 is returned if no compatible field is found.
5285  * <0 is returned on error.
5286  */
5287 static int bpf_core_match_member(const struct btf *local_btf,
5288                                  const struct bpf_core_accessor *local_acc,
5289                                  const struct btf *targ_btf,
5290                                  __u32 targ_id,
5291                                  struct bpf_core_spec *spec,
5292                                  __u32 *next_targ_id)
5293 {
5294         const struct btf_type *local_type, *targ_type;
5295         const struct btf_member *local_member, *m;
5296         const char *local_name, *targ_name;
5297         __u32 local_id;
5298         int i, n, found;
5299
5300         targ_type = skip_mods_and_typedefs(targ_btf, targ_id, &targ_id);
5301         if (!targ_type)
5302                 return -EINVAL;
5303         if (!btf_is_composite(targ_type))
5304                 return 0;
5305
5306         local_id = local_acc->type_id;
5307         local_type = btf__type_by_id(local_btf, local_id);
5308         local_member = btf_members(local_type) + local_acc->idx;
5309         local_name = btf__name_by_offset(local_btf, local_member->name_off);
5310
5311         n = btf_vlen(targ_type);
5312         m = btf_members(targ_type);
5313         for (i = 0; i < n; i++, m++) {
5314                 __u32 bit_offset;
5315
5316                 bit_offset = btf_member_bit_offset(targ_type, i);
5317
5318                 /* too deep struct/union/array nesting */
5319                 if (spec->raw_len == BPF_CORE_SPEC_MAX_LEN)
5320                         return -E2BIG;
5321
5322                 /* speculate this member will be the good one */
5323                 spec->bit_offset += bit_offset;
5324                 spec->raw_spec[spec->raw_len++] = i;
5325
5326                 targ_name = btf__name_by_offset(targ_btf, m->name_off);
5327                 if (str_is_empty(targ_name)) {
5328                         /* embedded struct/union, we need to go deeper */
5329                         found = bpf_core_match_member(local_btf, local_acc,
5330                                                       targ_btf, m->type,
5331                                                       spec, next_targ_id);
5332                         if (found) /* either found or error */
5333                                 return found;
5334                 } else if (strcmp(local_name, targ_name) == 0) {
5335                         /* matching named field */
5336                         struct bpf_core_accessor *targ_acc;
5337
5338                         targ_acc = &spec->spec[spec->len++];
5339                         targ_acc->type_id = targ_id;
5340                         targ_acc->idx = i;
5341                         targ_acc->name = targ_name;
5342
5343                         *next_targ_id = m->type;
5344                         found = bpf_core_fields_are_compat(local_btf,
5345                                                            local_member->type,
5346                                                            targ_btf, m->type);
5347                         if (!found)
5348                                 spec->len--; /* pop accessor */
5349                         return found;
5350                 }
5351                 /* member turned out not to be what we looked for */
5352                 spec->bit_offset -= bit_offset;
5353                 spec->raw_len--;
5354         }
5355
5356         return 0;
5357 }
5358
5359 /* Check local and target types for compatibility. This check is used for
5360  * type-based CO-RE relocations and follow slightly different rules than
5361  * field-based relocations. This function assumes that root types were already
5362  * checked for name match. Beyond that initial root-level name check, names
5363  * are completely ignored. Compatibility rules are as follows:
5364  *   - any two STRUCTs/UNIONs/FWDs/ENUMs/INTs are considered compatible, but
5365  *     kind should match for local and target types (i.e., STRUCT is not
5366  *     compatible with UNION);
5367  *   - for ENUMs, the size is ignored;
5368  *   - for INT, size and signedness are ignored;
5369  *   - for ARRAY, dimensionality is ignored, element types are checked for
5370  *     compatibility recursively;
5371  *   - CONST/VOLATILE/RESTRICT modifiers are ignored;
5372  *   - TYPEDEFs/PTRs are compatible if types they pointing to are compatible;
5373  *   - FUNC_PROTOs are compatible if they have compatible signature: same
5374  *     number of input args and compatible return and argument types.
5375  * These rules are not set in stone and probably will be adjusted as we get
5376  * more experience with using BPF CO-RE relocations.
5377  */
5378 static int bpf_core_types_are_compat(const struct btf *local_btf, __u32 local_id,
5379                                      const struct btf *targ_btf, __u32 targ_id)
5380 {
5381         const struct btf_type *local_type, *targ_type;
5382         int depth = 32; /* max recursion depth */
5383
5384         /* caller made sure that names match (ignoring flavor suffix) */
5385         local_type = btf__type_by_id(local_btf, local_id);
5386         targ_type = btf__type_by_id(targ_btf, targ_id);
5387         if (btf_kind(local_type) != btf_kind(targ_type))
5388                 return 0;
5389
5390 recur:
5391         depth--;
5392         if (depth < 0)
5393                 return -EINVAL;
5394
5395         local_type = skip_mods_and_typedefs(local_btf, local_id, &local_id);
5396         targ_type = skip_mods_and_typedefs(targ_btf, targ_id, &targ_id);
5397         if (!local_type || !targ_type)
5398                 return -EINVAL;
5399
5400         if (btf_kind(local_type) != btf_kind(targ_type))
5401                 return 0;
5402
5403         switch (btf_kind(local_type)) {
5404         case BTF_KIND_UNKN:
5405         case BTF_KIND_STRUCT:
5406         case BTF_KIND_UNION:
5407         case BTF_KIND_ENUM:
5408         case BTF_KIND_FWD:
5409                 return 1;
5410         case BTF_KIND_INT:
5411                 /* just reject deprecated bitfield-like integers; all other
5412                  * integers are by default compatible between each other
5413                  */
5414                 return btf_int_offset(local_type) == 0 && btf_int_offset(targ_type) == 0;
5415         case BTF_KIND_PTR:
5416                 local_id = local_type->type;
5417                 targ_id = targ_type->type;
5418                 goto recur;
5419         case BTF_KIND_ARRAY:
5420                 local_id = btf_array(local_type)->type;
5421                 targ_id = btf_array(targ_type)->type;
5422                 goto recur;
5423         case BTF_KIND_FUNC_PROTO: {
5424                 struct btf_param *local_p = btf_params(local_type);
5425                 struct btf_param *targ_p = btf_params(targ_type);
5426                 __u16 local_vlen = btf_vlen(local_type);
5427                 __u16 targ_vlen = btf_vlen(targ_type);
5428                 int i, err;
5429
5430                 if (local_vlen != targ_vlen)
5431                         return 0;
5432
5433                 for (i = 0; i < local_vlen; i++, local_p++, targ_p++) {
5434                         skip_mods_and_typedefs(local_btf, local_p->type, &local_id);
5435                         skip_mods_and_typedefs(targ_btf, targ_p->type, &targ_id);
5436                         err = bpf_core_types_are_compat(local_btf, local_id, targ_btf, targ_id);
5437                         if (err <= 0)
5438                                 return err;
5439                 }
5440
5441                 /* tail recurse for return type check */
5442                 skip_mods_and_typedefs(local_btf, local_type->type, &local_id);
5443                 skip_mods_and_typedefs(targ_btf, targ_type->type, &targ_id);
5444                 goto recur;
5445         }
5446         default:
5447                 pr_warn("unexpected kind %s relocated, local [%d], target [%d]\n",
5448                         btf_kind_str(local_type), local_id, targ_id);
5449                 return 0;
5450         }
5451 }
5452
5453 /*
5454  * Try to match local spec to a target type and, if successful, produce full
5455  * target spec (high-level, low-level + bit offset).
5456  */
5457 static int bpf_core_spec_match(struct bpf_core_spec *local_spec,
5458                                const struct btf *targ_btf, __u32 targ_id,
5459                                struct bpf_core_spec *targ_spec)
5460 {
5461         const struct btf_type *targ_type;
5462         const struct bpf_core_accessor *local_acc;
5463         struct bpf_core_accessor *targ_acc;
5464         int i, sz, matched;
5465
5466         memset(targ_spec, 0, sizeof(*targ_spec));
5467         targ_spec->btf = targ_btf;
5468         targ_spec->root_type_id = targ_id;
5469         targ_spec->relo_kind = local_spec->relo_kind;
5470
5471         if (core_relo_is_type_based(local_spec->relo_kind)) {
5472                 return bpf_core_types_are_compat(local_spec->btf,
5473                                                  local_spec->root_type_id,
5474                                                  targ_btf, targ_id);
5475         }
5476
5477         local_acc = &local_spec->spec[0];
5478         targ_acc = &targ_spec->spec[0];
5479
5480         if (core_relo_is_enumval_based(local_spec->relo_kind)) {
5481                 size_t local_essent_len, targ_essent_len;
5482                 const struct btf_enum *e;
5483                 const char *targ_name;
5484
5485                 /* has to resolve to an enum */
5486                 targ_type = skip_mods_and_typedefs(targ_spec->btf, targ_id, &targ_id);
5487                 if (!btf_is_enum(targ_type))
5488                         return 0;
5489
5490                 local_essent_len = bpf_core_essential_name_len(local_acc->name);
5491
5492                 for (i = 0, e = btf_enum(targ_type); i < btf_vlen(targ_type); i++, e++) {
5493                         targ_name = btf__name_by_offset(targ_spec->btf, e->name_off);
5494                         targ_essent_len = bpf_core_essential_name_len(targ_name);
5495                         if (targ_essent_len != local_essent_len)
5496                                 continue;
5497                         if (strncmp(local_acc->name, targ_name, local_essent_len) == 0) {
5498                                 targ_acc->type_id = targ_id;
5499                                 targ_acc->idx = i;
5500                                 targ_acc->name = targ_name;
5501                                 targ_spec->len++;
5502                                 targ_spec->raw_spec[targ_spec->raw_len] = targ_acc->idx;
5503                                 targ_spec->raw_len++;
5504                                 return 1;
5505                         }
5506                 }
5507                 return 0;
5508         }
5509
5510         if (!core_relo_is_field_based(local_spec->relo_kind))
5511                 return -EINVAL;
5512
5513         for (i = 0; i < local_spec->len; i++, local_acc++, targ_acc++) {
5514                 targ_type = skip_mods_and_typedefs(targ_spec->btf, targ_id,
5515                                                    &targ_id);
5516                 if (!targ_type)
5517                         return -EINVAL;
5518
5519                 if (local_acc->name) {
5520                         matched = bpf_core_match_member(local_spec->btf,
5521                                                         local_acc,
5522                                                         targ_btf, targ_id,
5523                                                         targ_spec, &targ_id);
5524                         if (matched <= 0)
5525                                 return matched;
5526                 } else {
5527                         /* for i=0, targ_id is already treated as array element
5528                          * type (because it's the original struct), for others
5529                          * we should find array element type first
5530                          */
5531                         if (i > 0) {
5532                                 const struct btf_array *a;
5533                                 bool flex;
5534
5535                                 if (!btf_is_array(targ_type))
5536                                         return 0;
5537
5538                                 a = btf_array(targ_type);
5539                                 flex = is_flex_arr(targ_btf, targ_acc - 1, a);
5540                                 if (!flex && local_acc->idx >= a->nelems)
5541                                         return 0;
5542                                 if (!skip_mods_and_typedefs(targ_btf, a->type,
5543                                                             &targ_id))
5544                                         return -EINVAL;
5545                         }
5546
5547                         /* too deep struct/union/array nesting */
5548                         if (targ_spec->raw_len == BPF_CORE_SPEC_MAX_LEN)
5549                                 return -E2BIG;
5550
5551                         targ_acc->type_id = targ_id;
5552                         targ_acc->idx = local_acc->idx;
5553                         targ_acc->name = NULL;
5554                         targ_spec->len++;
5555                         targ_spec->raw_spec[targ_spec->raw_len] = targ_acc->idx;
5556                         targ_spec->raw_len++;
5557
5558                         sz = btf__resolve_size(targ_btf, targ_id);
5559                         if (sz < 0)
5560                                 return sz;
5561                         targ_spec->bit_offset += local_acc->idx * sz * 8;
5562                 }
5563         }
5564
5565         return 1;
5566 }
5567
5568 static int bpf_core_calc_field_relo(const struct bpf_program *prog,
5569                                     const struct bpf_core_relo *relo,
5570                                     const struct bpf_core_spec *spec,
5571                                     __u32 *val, __u32 *field_sz, __u32 *type_id,
5572                                     bool *validate)
5573 {
5574         const struct bpf_core_accessor *acc;
5575         const struct btf_type *t;
5576         __u32 byte_off, byte_sz, bit_off, bit_sz, field_type_id;
5577         const struct btf_member *m;
5578         const struct btf_type *mt;
5579         bool bitfield;
5580         __s64 sz;
5581
5582         *field_sz = 0;
5583
5584         if (relo->kind == BPF_FIELD_EXISTS) {
5585                 *val = spec ? 1 : 0;
5586                 return 0;
5587         }
5588
5589         if (!spec)
5590                 return -EUCLEAN; /* request instruction poisoning */
5591
5592         acc = &spec->spec[spec->len - 1];
5593         t = btf__type_by_id(spec->btf, acc->type_id);
5594
5595         /* a[n] accessor needs special handling */
5596         if (!acc->name) {
5597                 if (relo->kind == BPF_FIELD_BYTE_OFFSET) {
5598                         *val = spec->bit_offset / 8;
5599                         /* remember field size for load/store mem size */
5600                         sz = btf__resolve_size(spec->btf, acc->type_id);
5601                         if (sz < 0)
5602                                 return -EINVAL;
5603                         *field_sz = sz;
5604                         *type_id = acc->type_id;
5605                 } else if (relo->kind == BPF_FIELD_BYTE_SIZE) {
5606                         sz = btf__resolve_size(spec->btf, acc->type_id);
5607                         if (sz < 0)
5608                                 return -EINVAL;
5609                         *val = sz;
5610                 } else {
5611                         pr_warn("prog '%s': relo %d at insn #%d can't be applied to array access\n",
5612                                 prog->name, relo->kind, relo->insn_off / 8);
5613                         return -EINVAL;
5614                 }
5615                 if (validate)
5616                         *validate = true;
5617                 return 0;
5618         }
5619
5620         m = btf_members(t) + acc->idx;
5621         mt = skip_mods_and_typedefs(spec->btf, m->type, &field_type_id);
5622         bit_off = spec->bit_offset;
5623         bit_sz = btf_member_bitfield_size(t, acc->idx);
5624
5625         bitfield = bit_sz > 0;
5626         if (bitfield) {
5627                 byte_sz = mt->size;
5628                 byte_off = bit_off / 8 / byte_sz * byte_sz;
5629                 /* figure out smallest int size necessary for bitfield load */
5630                 while (bit_off + bit_sz - byte_off * 8 > byte_sz * 8) {
5631                         if (byte_sz >= 8) {
5632                                 /* bitfield can't be read with 64-bit read */
5633                                 pr_warn("prog '%s': relo %d at insn #%d can't be satisfied for bitfield\n",
5634                                         prog->name, relo->kind, relo->insn_off / 8);
5635                                 return -E2BIG;
5636                         }
5637                         byte_sz *= 2;
5638                         byte_off = bit_off / 8 / byte_sz * byte_sz;
5639                 }
5640         } else {
5641                 sz = btf__resolve_size(spec->btf, field_type_id);
5642                 if (sz < 0)
5643                         return -EINVAL;
5644                 byte_sz = sz;
5645                 byte_off = spec->bit_offset / 8;
5646                 bit_sz = byte_sz * 8;
5647         }
5648
5649         /* for bitfields, all the relocatable aspects are ambiguous and we
5650          * might disagree with compiler, so turn off validation of expected
5651          * value, except for signedness
5652          */
5653         if (validate)
5654                 *validate = !bitfield;
5655
5656         switch (relo->kind) {
5657         case BPF_FIELD_BYTE_OFFSET:
5658                 *val = byte_off;
5659                 if (!bitfield) {
5660                         *field_sz = byte_sz;
5661                         *type_id = field_type_id;
5662                 }
5663                 break;
5664         case BPF_FIELD_BYTE_SIZE:
5665                 *val = byte_sz;
5666                 break;
5667         case BPF_FIELD_SIGNED:
5668                 /* enums will be assumed unsigned */
5669                 *val = btf_is_enum(mt) ||
5670                        (btf_int_encoding(mt) & BTF_INT_SIGNED);
5671                 if (validate)
5672                         *validate = true; /* signedness is never ambiguous */
5673                 break;
5674         case BPF_FIELD_LSHIFT_U64:
5675 #if __BYTE_ORDER == __LITTLE_ENDIAN
5676                 *val = 64 - (bit_off + bit_sz - byte_off  * 8);
5677 #else
5678                 *val = (8 - byte_sz) * 8 + (bit_off - byte_off * 8);
5679 #endif
5680                 break;
5681         case BPF_FIELD_RSHIFT_U64:
5682                 *val = 64 - bit_sz;
5683                 if (validate)
5684                         *validate = true; /* right shift is never ambiguous */
5685                 break;
5686         case BPF_FIELD_EXISTS:
5687         default:
5688                 return -EOPNOTSUPP;
5689         }
5690
5691         return 0;
5692 }
5693
5694 static int bpf_core_calc_type_relo(const struct bpf_core_relo *relo,
5695                                    const struct bpf_core_spec *spec,
5696                                    __u32 *val)
5697 {
5698         __s64 sz;
5699
5700         /* type-based relos return zero when target type is not found */
5701         if (!spec) {
5702                 *val = 0;
5703                 return 0;
5704         }
5705
5706         switch (relo->kind) {
5707         case BPF_TYPE_ID_TARGET:
5708                 *val = spec->root_type_id;
5709                 break;
5710         case BPF_TYPE_EXISTS:
5711                 *val = 1;
5712                 break;
5713         case BPF_TYPE_SIZE:
5714                 sz = btf__resolve_size(spec->btf, spec->root_type_id);
5715                 if (sz < 0)
5716                         return -EINVAL;
5717                 *val = sz;
5718                 break;
5719         case BPF_TYPE_ID_LOCAL:
5720         /* BPF_TYPE_ID_LOCAL is handled specially and shouldn't get here */
5721         default:
5722                 return -EOPNOTSUPP;
5723         }
5724
5725         return 0;
5726 }
5727
5728 static int bpf_core_calc_enumval_relo(const struct bpf_core_relo *relo,
5729                                       const struct bpf_core_spec *spec,
5730                                       __u32 *val)
5731 {
5732         const struct btf_type *t;
5733         const struct btf_enum *e;
5734
5735         switch (relo->kind) {
5736         case BPF_ENUMVAL_EXISTS:
5737                 *val = spec ? 1 : 0;
5738                 break;
5739         case BPF_ENUMVAL_VALUE:
5740                 if (!spec)
5741                         return -EUCLEAN; /* request instruction poisoning */
5742                 t = btf__type_by_id(spec->btf, spec->spec[0].type_id);
5743                 e = btf_enum(t) + spec->spec[0].idx;
5744                 *val = e->val;
5745                 break;
5746         default:
5747                 return -EOPNOTSUPP;
5748         }
5749
5750         return 0;
5751 }
5752
5753 struct bpf_core_relo_res
5754 {
5755         /* expected value in the instruction, unless validate == false */
5756         __u32 orig_val;
5757         /* new value that needs to be patched up to */
5758         __u32 new_val;
5759         /* relocation unsuccessful, poison instruction, but don't fail load */
5760         bool poison;
5761         /* some relocations can't be validated against orig_val */
5762         bool validate;
5763         /* for field byte offset relocations or the forms:
5764          *     *(T *)(rX + <off>) = rY
5765          *     rX = *(T *)(rY + <off>),
5766          * we remember original and resolved field size to adjust direct
5767          * memory loads of pointers and integers; this is necessary for 32-bit
5768          * host kernel architectures, but also allows to automatically
5769          * relocate fields that were resized from, e.g., u32 to u64, etc.
5770          */
5771         bool fail_memsz_adjust;
5772         __u32 orig_sz;
5773         __u32 orig_type_id;
5774         __u32 new_sz;
5775         __u32 new_type_id;
5776 };
5777
5778 /* Calculate original and target relocation values, given local and target
5779  * specs and relocation kind. These values are calculated for each candidate.
5780  * If there are multiple candidates, resulting values should all be consistent
5781  * with each other. Otherwise, libbpf will refuse to proceed due to ambiguity.
5782  * If instruction has to be poisoned, *poison will be set to true.
5783  */
5784 static int bpf_core_calc_relo(const struct bpf_program *prog,
5785                               const struct bpf_core_relo *relo,
5786                               int relo_idx,
5787                               const struct bpf_core_spec *local_spec,
5788                               const struct bpf_core_spec *targ_spec,
5789                               struct bpf_core_relo_res *res)
5790 {
5791         int err = -EOPNOTSUPP;
5792
5793         res->orig_val = 0;
5794         res->new_val = 0;
5795         res->poison = false;
5796         res->validate = true;
5797         res->fail_memsz_adjust = false;
5798         res->orig_sz = res->new_sz = 0;
5799         res->orig_type_id = res->new_type_id = 0;
5800
5801         if (core_relo_is_field_based(relo->kind)) {
5802                 err = bpf_core_calc_field_relo(prog, relo, local_spec,
5803                                                &res->orig_val, &res->orig_sz,
5804                                                &res->orig_type_id, &res->validate);
5805                 err = err ?: bpf_core_calc_field_relo(prog, relo, targ_spec,
5806                                                       &res->new_val, &res->new_sz,
5807                                                       &res->new_type_id, NULL);
5808                 if (err)
5809                         goto done;
5810                 /* Validate if it's safe to adjust load/store memory size.
5811                  * Adjustments are performed only if original and new memory
5812                  * sizes differ.
5813                  */
5814                 res->fail_memsz_adjust = false;
5815                 if (res->orig_sz != res->new_sz) {
5816                         const struct btf_type *orig_t, *new_t;
5817
5818                         orig_t = btf__type_by_id(local_spec->btf, res->orig_type_id);
5819                         new_t = btf__type_by_id(targ_spec->btf, res->new_type_id);
5820
5821                         /* There are two use cases in which it's safe to
5822                          * adjust load/store's mem size:
5823                          *   - reading a 32-bit kernel pointer, while on BPF
5824                          *   size pointers are always 64-bit; in this case
5825                          *   it's safe to "downsize" instruction size due to
5826                          *   pointer being treated as unsigned integer with
5827                          *   zero-extended upper 32-bits;
5828                          *   - reading unsigned integers, again due to
5829                          *   zero-extension is preserving the value correctly.
5830                          *
5831                          * In all other cases it's incorrect to attempt to
5832                          * load/store field because read value will be
5833                          * incorrect, so we poison relocated instruction.
5834                          */
5835                         if (btf_is_ptr(orig_t) && btf_is_ptr(new_t))
5836                                 goto done;
5837                         if (btf_is_int(orig_t) && btf_is_int(new_t) &&
5838                             btf_int_encoding(orig_t) != BTF_INT_SIGNED &&
5839                             btf_int_encoding(new_t) != BTF_INT_SIGNED)
5840                                 goto done;
5841
5842                         /* mark as invalid mem size adjustment, but this will
5843                          * only be checked for LDX/STX/ST insns
5844                          */
5845                         res->fail_memsz_adjust = true;
5846                 }
5847         } else if (core_relo_is_type_based(relo->kind)) {
5848                 err = bpf_core_calc_type_relo(relo, local_spec, &res->orig_val);
5849                 err = err ?: bpf_core_calc_type_relo(relo, targ_spec, &res->new_val);
5850         } else if (core_relo_is_enumval_based(relo->kind)) {
5851                 err = bpf_core_calc_enumval_relo(relo, local_spec, &res->orig_val);
5852                 err = err ?: bpf_core_calc_enumval_relo(relo, targ_spec, &res->new_val);
5853         }
5854
5855 done:
5856         if (err == -EUCLEAN) {
5857                 /* EUCLEAN is used to signal instruction poisoning request */
5858                 res->poison = true;
5859                 err = 0;
5860         } else if (err == -EOPNOTSUPP) {
5861                 /* EOPNOTSUPP means unknown/unsupported relocation */
5862                 pr_warn("prog '%s': relo #%d: unrecognized CO-RE relocation %s (%d) at insn #%d\n",
5863                         prog->name, relo_idx, core_relo_kind_str(relo->kind),
5864                         relo->kind, relo->insn_off / 8);
5865         }
5866
5867         return err;
5868 }
5869
5870 /*
5871  * Turn instruction for which CO_RE relocation failed into invalid one with
5872  * distinct signature.
5873  */
5874 static void bpf_core_poison_insn(struct bpf_program *prog, int relo_idx,
5875                                  int insn_idx, struct bpf_insn *insn)
5876 {
5877         pr_debug("prog '%s': relo #%d: substituting insn #%d w/ invalid insn\n",
5878                  prog->name, relo_idx, insn_idx);
5879         insn->code = BPF_JMP | BPF_CALL;
5880         insn->dst_reg = 0;
5881         insn->src_reg = 0;
5882         insn->off = 0;
5883         /* if this instruction is reachable (not a dead code),
5884          * verifier will complain with the following message:
5885          * invalid func unknown#195896080
5886          */
5887         insn->imm = 195896080; /* => 0xbad2310 => "bad relo" */
5888 }
5889
5890 static int insn_bpf_size_to_bytes(struct bpf_insn *insn)
5891 {
5892         switch (BPF_SIZE(insn->code)) {
5893         case BPF_DW: return 8;
5894         case BPF_W: return 4;
5895         case BPF_H: return 2;
5896         case BPF_B: return 1;
5897         default: return -1;
5898         }
5899 }
5900
5901 static int insn_bytes_to_bpf_size(__u32 sz)
5902 {
5903         switch (sz) {
5904         case 8: return BPF_DW;
5905         case 4: return BPF_W;
5906         case 2: return BPF_H;
5907         case 1: return BPF_B;
5908         default: return -1;
5909         }
5910 }
5911
5912 /*
5913  * Patch relocatable BPF instruction.
5914  *
5915  * Patched value is determined by relocation kind and target specification.
5916  * For existence relocations target spec will be NULL if field/type is not found.
5917  * Expected insn->imm value is determined using relocation kind and local
5918  * spec, and is checked before patching instruction. If actual insn->imm value
5919  * is wrong, bail out with error.
5920  *
5921  * Currently supported classes of BPF instruction are:
5922  * 1. rX = <imm> (assignment with immediate operand);
5923  * 2. rX += <imm> (arithmetic operations with immediate operand);
5924  * 3. rX = <imm64> (load with 64-bit immediate value);
5925  * 4. rX = *(T *)(rY + <off>), where T is one of {u8, u16, u32, u64};
5926  * 5. *(T *)(rX + <off>) = rY, where T is one of {u8, u16, u32, u64};
5927  * 6. *(T *)(rX + <off>) = <imm>, where T is one of {u8, u16, u32, u64}.
5928  */
5929 static int bpf_core_patch_insn(struct bpf_program *prog,
5930                                const struct bpf_core_relo *relo,
5931                                int relo_idx,
5932                                const struct bpf_core_relo_res *res)
5933 {
5934         __u32 orig_val, new_val;
5935         struct bpf_insn *insn;
5936         int insn_idx;
5937         __u8 class;
5938
5939         if (relo->insn_off % BPF_INSN_SZ)
5940                 return -EINVAL;
5941         insn_idx = relo->insn_off / BPF_INSN_SZ;
5942         /* adjust insn_idx from section frame of reference to the local
5943          * program's frame of reference; (sub-)program code is not yet
5944          * relocated, so it's enough to just subtract in-section offset
5945          */
5946         insn_idx = insn_idx - prog->sec_insn_off;
5947         insn = &prog->insns[insn_idx];
5948         class = BPF_CLASS(insn->code);
5949
5950         if (res->poison) {
5951 poison:
5952                 /* poison second part of ldimm64 to avoid confusing error from
5953                  * verifier about "unknown opcode 00"
5954                  */
5955                 if (is_ldimm64_insn(insn))
5956                         bpf_core_poison_insn(prog, relo_idx, insn_idx + 1, insn + 1);
5957                 bpf_core_poison_insn(prog, relo_idx, insn_idx, insn);
5958                 return 0;
5959         }
5960
5961         orig_val = res->orig_val;
5962         new_val = res->new_val;
5963
5964         switch (class) {
5965         case BPF_ALU:
5966         case BPF_ALU64:
5967                 if (BPF_SRC(insn->code) != BPF_K)
5968                         return -EINVAL;
5969                 if (res->validate && insn->imm != orig_val) {
5970                         pr_warn("prog '%s': relo #%d: unexpected insn #%d (ALU/ALU64) value: got %u, exp %u -> %u\n",
5971                                 prog->name, relo_idx,
5972                                 insn_idx, insn->imm, orig_val, new_val);
5973                         return -EINVAL;
5974                 }
5975                 orig_val = insn->imm;
5976                 insn->imm = new_val;
5977                 pr_debug("prog '%s': relo #%d: patched insn #%d (ALU/ALU64) imm %u -> %u\n",
5978                          prog->name, relo_idx, insn_idx,
5979                          orig_val, new_val);
5980                 break;
5981         case BPF_LDX:
5982         case BPF_ST:
5983         case BPF_STX:
5984                 if (res->validate && insn->off != orig_val) {
5985                         pr_warn("prog '%s': relo #%d: unexpected insn #%d (LDX/ST/STX) value: got %u, exp %u -> %u\n",
5986                                 prog->name, relo_idx, insn_idx, insn->off, orig_val, new_val);
5987                         return -EINVAL;
5988                 }
5989                 if (new_val > SHRT_MAX) {
5990                         pr_warn("prog '%s': relo #%d: insn #%d (LDX/ST/STX) value too big: %u\n",
5991                                 prog->name, relo_idx, insn_idx, new_val);
5992                         return -ERANGE;
5993                 }
5994                 if (res->fail_memsz_adjust) {
5995                         pr_warn("prog '%s': relo #%d: insn #%d (LDX/ST/STX) accesses field incorrectly. "
5996                                 "Make sure you are accessing pointers, unsigned integers, or fields of matching type and size.\n",
5997                                 prog->name, relo_idx, insn_idx);
5998                         goto poison;
5999                 }
6000
6001                 orig_val = insn->off;
6002                 insn->off = new_val;
6003                 pr_debug("prog '%s': relo #%d: patched insn #%d (LDX/ST/STX) off %u -> %u\n",
6004                          prog->name, relo_idx, insn_idx, orig_val, new_val);
6005
6006                 if (res->new_sz != res->orig_sz) {
6007                         int insn_bytes_sz, insn_bpf_sz;
6008
6009                         insn_bytes_sz = insn_bpf_size_to_bytes(insn);
6010                         if (insn_bytes_sz != res->orig_sz) {
6011                                 pr_warn("prog '%s': relo #%d: insn #%d (LDX/ST/STX) unexpected mem size: got %d, exp %u\n",
6012                                         prog->name, relo_idx, insn_idx, insn_bytes_sz, res->orig_sz);
6013                                 return -EINVAL;
6014                         }
6015
6016                         insn_bpf_sz = insn_bytes_to_bpf_size(res->new_sz);
6017                         if (insn_bpf_sz < 0) {
6018                                 pr_warn("prog '%s': relo #%d: insn #%d (LDX/ST/STX) invalid new mem size: %u\n",
6019                                         prog->name, relo_idx, insn_idx, res->new_sz);
6020                                 return -EINVAL;
6021                         }
6022
6023                         insn->code = BPF_MODE(insn->code) | insn_bpf_sz | BPF_CLASS(insn->code);
6024                         pr_debug("prog '%s': relo #%d: patched insn #%d (LDX/ST/STX) mem_sz %u -> %u\n",
6025                                  prog->name, relo_idx, insn_idx, res->orig_sz, res->new_sz);
6026                 }
6027                 break;
6028         case BPF_LD: {
6029                 __u64 imm;
6030
6031                 if (!is_ldimm64_insn(insn) ||
6032                     insn[0].src_reg != 0 || insn[0].off != 0 ||
6033                     insn_idx + 1 >= prog->insns_cnt ||
6034                     insn[1].code != 0 || insn[1].dst_reg != 0 ||
6035                     insn[1].src_reg != 0 || insn[1].off != 0) {
6036                         pr_warn("prog '%s': relo #%d: insn #%d (LDIMM64) has unexpected form\n",
6037                                 prog->name, relo_idx, insn_idx);
6038                         return -EINVAL;
6039                 }
6040
6041                 imm = insn[0].imm + ((__u64)insn[1].imm << 32);
6042                 if (res->validate && imm != orig_val) {
6043                         pr_warn("prog '%s': relo #%d: unexpected insn #%d (LDIMM64) value: got %llu, exp %u -> %u\n",
6044                                 prog->name, relo_idx,
6045                                 insn_idx, (unsigned long long)imm,
6046                                 orig_val, new_val);
6047                         return -EINVAL;
6048                 }
6049
6050                 insn[0].imm = new_val;
6051                 insn[1].imm = 0; /* currently only 32-bit values are supported */
6052                 pr_debug("prog '%s': relo #%d: patched insn #%d (LDIMM64) imm64 %llu -> %u\n",
6053                          prog->name, relo_idx, insn_idx,
6054                          (unsigned long long)imm, new_val);
6055                 break;
6056         }
6057         default:
6058                 pr_warn("prog '%s': relo #%d: trying to relocate unrecognized insn #%d, code:0x%x, src:0x%x, dst:0x%x, off:0x%x, imm:0x%x\n",
6059                         prog->name, relo_idx, insn_idx, insn->code,
6060                         insn->src_reg, insn->dst_reg, insn->off, insn->imm);
6061                 return -EINVAL;
6062         }
6063
6064         return 0;
6065 }
6066
6067 /* Output spec definition in the format:
6068  * [<type-id>] (<type-name>) + <raw-spec> => <offset>@<spec>,
6069  * where <spec> is a C-syntax view of recorded field access, e.g.: x.a[3].b
6070  */
6071 static void bpf_core_dump_spec(int level, const struct bpf_core_spec *spec)
6072 {
6073         const struct btf_type *t;
6074         const struct btf_enum *e;
6075         const char *s;
6076         __u32 type_id;
6077         int i;
6078
6079         type_id = spec->root_type_id;
6080         t = btf__type_by_id(spec->btf, type_id);
6081         s = btf__name_by_offset(spec->btf, t->name_off);
6082
6083         libbpf_print(level, "[%u] %s %s", type_id, btf_kind_str(t), str_is_empty(s) ? "<anon>" : s);
6084
6085         if (core_relo_is_type_based(spec->relo_kind))
6086                 return;
6087
6088         if (core_relo_is_enumval_based(spec->relo_kind)) {
6089                 t = skip_mods_and_typedefs(spec->btf, type_id, NULL);
6090                 e = btf_enum(t) + spec->raw_spec[0];
6091                 s = btf__name_by_offset(spec->btf, e->name_off);
6092
6093                 libbpf_print(level, "::%s = %u", s, e->val);
6094                 return;
6095         }
6096
6097         if (core_relo_is_field_based(spec->relo_kind)) {
6098                 for (i = 0; i < spec->len; i++) {
6099                         if (spec->spec[i].name)
6100                                 libbpf_print(level, ".%s", spec->spec[i].name);
6101                         else if (i > 0 || spec->spec[i].idx > 0)
6102                                 libbpf_print(level, "[%u]", spec->spec[i].idx);
6103                 }
6104
6105                 libbpf_print(level, " (");
6106                 for (i = 0; i < spec->raw_len; i++)
6107                         libbpf_print(level, "%s%d", i == 0 ? "" : ":", spec->raw_spec[i]);
6108
6109                 if (spec->bit_offset % 8)
6110                         libbpf_print(level, " @ offset %u.%u)",
6111                                      spec->bit_offset / 8, spec->bit_offset % 8);
6112                 else
6113                         libbpf_print(level, " @ offset %u)", spec->bit_offset / 8);
6114                 return;
6115         }
6116 }
6117
6118 static size_t bpf_core_hash_fn(const void *key, void *ctx)
6119 {
6120         return (size_t)key;
6121 }
6122
6123 static bool bpf_core_equal_fn(const void *k1, const void *k2, void *ctx)
6124 {
6125         return k1 == k2;
6126 }
6127
6128 static void *u32_as_hash_key(__u32 x)
6129 {
6130         return (void *)(uintptr_t)x;
6131 }
6132
6133 /*
6134  * CO-RE relocate single instruction.
6135  *
6136  * The outline and important points of the algorithm:
6137  * 1. For given local type, find corresponding candidate target types.
6138  *    Candidate type is a type with the same "essential" name, ignoring
6139  *    everything after last triple underscore (___). E.g., `sample`,
6140  *    `sample___flavor_one`, `sample___flavor_another_one`, are all candidates
6141  *    for each other. Names with triple underscore are referred to as
6142  *    "flavors" and are useful, among other things, to allow to
6143  *    specify/support incompatible variations of the same kernel struct, which
6144  *    might differ between different kernel versions and/or build
6145  *    configurations.
6146  *
6147  *    N.B. Struct "flavors" could be generated by bpftool's BTF-to-C
6148  *    converter, when deduplicated BTF of a kernel still contains more than
6149  *    one different types with the same name. In that case, ___2, ___3, etc
6150  *    are appended starting from second name conflict. But start flavors are
6151  *    also useful to be defined "locally", in BPF program, to extract same
6152  *    data from incompatible changes between different kernel
6153  *    versions/configurations. For instance, to handle field renames between
6154  *    kernel versions, one can use two flavors of the struct name with the
6155  *    same common name and use conditional relocations to extract that field,
6156  *    depending on target kernel version.
6157  * 2. For each candidate type, try to match local specification to this
6158  *    candidate target type. Matching involves finding corresponding
6159  *    high-level spec accessors, meaning that all named fields should match,
6160  *    as well as all array accesses should be within the actual bounds. Also,
6161  *    types should be compatible (see bpf_core_fields_are_compat for details).
6162  * 3. It is supported and expected that there might be multiple flavors
6163  *    matching the spec. As long as all the specs resolve to the same set of
6164  *    offsets across all candidates, there is no error. If there is any
6165  *    ambiguity, CO-RE relocation will fail. This is necessary to accomodate
6166  *    imprefection of BTF deduplication, which can cause slight duplication of
6167  *    the same BTF type, if some directly or indirectly referenced (by
6168  *    pointer) type gets resolved to different actual types in different
6169  *    object files. If such situation occurs, deduplicated BTF will end up
6170  *    with two (or more) structurally identical types, which differ only in
6171  *    types they refer to through pointer. This should be OK in most cases and
6172  *    is not an error.
6173  * 4. Candidate types search is performed by linearly scanning through all
6174  *    types in target BTF. It is anticipated that this is overall more
6175  *    efficient memory-wise and not significantly worse (if not better)
6176  *    CPU-wise compared to prebuilding a map from all local type names to
6177  *    a list of candidate type names. It's also sped up by caching resolved
6178  *    list of matching candidates per each local "root" type ID, that has at
6179  *    least one bpf_core_relo associated with it. This list is shared
6180  *    between multiple relocations for the same type ID and is updated as some
6181  *    of the candidates are pruned due to structural incompatibility.
6182  */
6183 static int bpf_core_apply_relo(struct bpf_program *prog,
6184                                const struct bpf_core_relo *relo,
6185                                int relo_idx,
6186                                const struct btf *local_btf,
6187                                struct hashmap *cand_cache)
6188 {
6189         struct bpf_core_spec local_spec, cand_spec, targ_spec = {};
6190         const void *type_key = u32_as_hash_key(relo->type_id);
6191         struct bpf_core_relo_res cand_res, targ_res;
6192         const struct btf_type *local_type;
6193         const char *local_name;
6194         struct core_cand_list *cands = NULL;
6195         __u32 local_id;
6196         const char *spec_str;
6197         int i, j, err;
6198
6199         local_id = relo->type_id;
6200         local_type = btf__type_by_id(local_btf, local_id);
6201         if (!local_type)
6202                 return -EINVAL;
6203
6204         local_name = btf__name_by_offset(local_btf, local_type->name_off);
6205         if (!local_name)
6206                 return -EINVAL;
6207
6208         spec_str = btf__name_by_offset(local_btf, relo->access_str_off);
6209         if (str_is_empty(spec_str))
6210                 return -EINVAL;
6211
6212         if (prog->obj->gen_loader) {
6213                 pr_warn("// TODO core_relo: prog %td insn[%d] %s %s kind %d\n",
6214                         prog - prog->obj->programs, relo->insn_off / 8,
6215                         local_name, spec_str, relo->kind);
6216                 return -ENOTSUP;
6217         }
6218         err = bpf_core_parse_spec(local_btf, local_id, spec_str, relo->kind, &local_spec);
6219         if (err) {
6220                 pr_warn("prog '%s': relo #%d: parsing [%d] %s %s + %s failed: %d\n",
6221                         prog->name, relo_idx, local_id, btf_kind_str(local_type),
6222                         str_is_empty(local_name) ? "<anon>" : local_name,
6223                         spec_str, err);
6224                 return -EINVAL;
6225         }
6226
6227         pr_debug("prog '%s': relo #%d: kind <%s> (%d), spec is ", prog->name,
6228                  relo_idx, core_relo_kind_str(relo->kind), relo->kind);
6229         bpf_core_dump_spec(LIBBPF_DEBUG, &local_spec);
6230         libbpf_print(LIBBPF_DEBUG, "\n");
6231
6232         /* TYPE_ID_LOCAL relo is special and doesn't need candidate search */
6233         if (relo->kind == BPF_TYPE_ID_LOCAL) {
6234                 targ_res.validate = true;
6235                 targ_res.poison = false;
6236                 targ_res.orig_val = local_spec.root_type_id;
6237                 targ_res.new_val = local_spec.root_type_id;
6238                 goto patch_insn;
6239         }
6240
6241         /* libbpf doesn't support candidate search for anonymous types */
6242         if (str_is_empty(spec_str)) {
6243                 pr_warn("prog '%s': relo #%d: <%s> (%d) relocation doesn't support anonymous types\n",
6244                         prog->name, relo_idx, core_relo_kind_str(relo->kind), relo->kind);
6245                 return -EOPNOTSUPP;
6246         }
6247
6248         if (!hashmap__find(cand_cache, type_key, (void **)&cands)) {
6249                 cands = bpf_core_find_cands(prog->obj, local_btf, local_id);
6250                 if (IS_ERR(cands)) {
6251                         pr_warn("prog '%s': relo #%d: target candidate search failed for [%d] %s %s: %ld\n",
6252                                 prog->name, relo_idx, local_id, btf_kind_str(local_type),
6253                                 local_name, PTR_ERR(cands));
6254                         return PTR_ERR(cands);
6255                 }
6256                 err = hashmap__set(cand_cache, type_key, cands, NULL, NULL);
6257                 if (err) {
6258                         bpf_core_free_cands(cands);
6259                         return err;
6260                 }
6261         }
6262
6263         for (i = 0, j = 0; i < cands->len; i++) {
6264                 err = bpf_core_spec_match(&local_spec, cands->cands[i].btf,
6265                                           cands->cands[i].id, &cand_spec);
6266                 if (err < 0) {
6267                         pr_warn("prog '%s': relo #%d: error matching candidate #%d ",
6268                                 prog->name, relo_idx, i);
6269                         bpf_core_dump_spec(LIBBPF_WARN, &cand_spec);
6270                         libbpf_print(LIBBPF_WARN, ": %d\n", err);
6271                         return err;
6272                 }
6273
6274                 pr_debug("prog '%s': relo #%d: %s candidate #%d ", prog->name,
6275                          relo_idx, err == 0 ? "non-matching" : "matching", i);
6276                 bpf_core_dump_spec(LIBBPF_DEBUG, &cand_spec);
6277                 libbpf_print(LIBBPF_DEBUG, "\n");
6278
6279                 if (err == 0)
6280                         continue;
6281
6282                 err = bpf_core_calc_relo(prog, relo, relo_idx, &local_spec, &cand_spec, &cand_res);
6283                 if (err)
6284                         return err;
6285
6286                 if (j == 0) {
6287                         targ_res = cand_res;
6288                         targ_spec = cand_spec;
6289                 } else if (cand_spec.bit_offset != targ_spec.bit_offset) {
6290                         /* if there are many field relo candidates, they
6291                          * should all resolve to the same bit offset
6292                          */
6293                         pr_warn("prog '%s': relo #%d: field offset ambiguity: %u != %u\n",
6294                                 prog->name, relo_idx, cand_spec.bit_offset,
6295                                 targ_spec.bit_offset);
6296                         return -EINVAL;
6297                 } else if (cand_res.poison != targ_res.poison || cand_res.new_val != targ_res.new_val) {
6298                         /* all candidates should result in the same relocation
6299                          * decision and value, otherwise it's dangerous to
6300                          * proceed due to ambiguity
6301                          */
6302                         pr_warn("prog '%s': relo #%d: relocation decision ambiguity: %s %u != %s %u\n",
6303                                 prog->name, relo_idx,
6304                                 cand_res.poison ? "failure" : "success", cand_res.new_val,
6305                                 targ_res.poison ? "failure" : "success", targ_res.new_val);
6306                         return -EINVAL;
6307                 }
6308
6309                 cands->cands[j++] = cands->cands[i];
6310         }
6311
6312         /*
6313          * For BPF_FIELD_EXISTS relo or when used BPF program has field
6314          * existence checks or kernel version/config checks, it's expected
6315          * that we might not find any candidates. In this case, if field
6316          * wasn't found in any candidate, the list of candidates shouldn't
6317          * change at all, we'll just handle relocating appropriately,
6318          * depending on relo's kind.
6319          */
6320         if (j > 0)
6321                 cands->len = j;
6322
6323         /*
6324          * If no candidates were found, it might be both a programmer error,
6325          * as well as expected case, depending whether instruction w/
6326          * relocation is guarded in some way that makes it unreachable (dead
6327          * code) if relocation can't be resolved. This is handled in
6328          * bpf_core_patch_insn() uniformly by replacing that instruction with
6329          * BPF helper call insn (using invalid helper ID). If that instruction
6330          * is indeed unreachable, then it will be ignored and eliminated by
6331          * verifier. If it was an error, then verifier will complain and point
6332          * to a specific instruction number in its log.
6333          */
6334         if (j == 0) {
6335                 pr_debug("prog '%s': relo #%d: no matching targets found\n",
6336                          prog->name, relo_idx);
6337
6338                 /* calculate single target relo result explicitly */
6339                 err = bpf_core_calc_relo(prog, relo, relo_idx, &local_spec, NULL, &targ_res);
6340                 if (err)
6341                         return err;
6342         }
6343
6344 patch_insn:
6345         /* bpf_core_patch_insn() should know how to handle missing targ_spec */
6346         err = bpf_core_patch_insn(prog, relo, relo_idx, &targ_res);
6347         if (err) {
6348                 pr_warn("prog '%s': relo #%d: failed to patch insn #%zu: %d\n",
6349                         prog->name, relo_idx, relo->insn_off / BPF_INSN_SZ, err);
6350                 return -EINVAL;
6351         }
6352
6353         return 0;
6354 }
6355
6356 static int
6357 bpf_object__relocate_core(struct bpf_object *obj, const char *targ_btf_path)
6358 {
6359         const struct btf_ext_info_sec *sec;
6360         const struct bpf_core_relo *rec;
6361         const struct btf_ext_info *seg;
6362         struct hashmap_entry *entry;
6363         struct hashmap *cand_cache = NULL;
6364         struct bpf_program *prog;
6365         const char *sec_name;
6366         int i, err = 0, insn_idx, sec_idx;
6367
6368         if (obj->btf_ext->core_relo_info.len == 0)
6369                 return 0;
6370
6371         if (targ_btf_path) {
6372                 obj->btf_vmlinux_override = btf__parse(targ_btf_path, NULL);
6373                 err = libbpf_get_error(obj->btf_vmlinux_override);
6374                 if (err) {
6375                         pr_warn("failed to parse target BTF: %d\n", err);
6376                         return err;
6377                 }
6378         }
6379
6380         cand_cache = hashmap__new(bpf_core_hash_fn, bpf_core_equal_fn, NULL);
6381         if (IS_ERR(cand_cache)) {
6382                 err = PTR_ERR(cand_cache);
6383                 goto out;
6384         }
6385
6386         seg = &obj->btf_ext->core_relo_info;
6387         for_each_btf_ext_sec(seg, sec) {
6388                 sec_name = btf__name_by_offset(obj->btf, sec->sec_name_off);
6389                 if (str_is_empty(sec_name)) {
6390                         err = -EINVAL;
6391                         goto out;
6392                 }
6393                 /* bpf_object's ELF is gone by now so it's not easy to find
6394                  * section index by section name, but we can find *any*
6395                  * bpf_program within desired section name and use it's
6396                  * prog->sec_idx to do a proper search by section index and
6397                  * instruction offset
6398                  */
6399                 prog = NULL;
6400                 for (i = 0; i < obj->nr_programs; i++) {
6401                         prog = &obj->programs[i];
6402                         if (strcmp(prog->sec_name, sec_name) == 0)
6403                                 break;
6404                 }
6405                 if (!prog) {
6406                         pr_warn("sec '%s': failed to find a BPF program\n", sec_name);
6407                         return -ENOENT;
6408                 }
6409                 sec_idx = prog->sec_idx;
6410
6411                 pr_debug("sec '%s': found %d CO-RE relocations\n",
6412                          sec_name, sec->num_info);
6413
6414                 for_each_btf_ext_rec(seg, sec, i, rec) {
6415                         insn_idx = rec->insn_off / BPF_INSN_SZ;
6416                         prog = find_prog_by_sec_insn(obj, sec_idx, insn_idx);
6417                         if (!prog) {
6418                                 pr_warn("sec '%s': failed to find program at insn #%d for CO-RE offset relocation #%d\n",
6419                                         sec_name, insn_idx, i);
6420                                 err = -EINVAL;
6421                                 goto out;
6422                         }
6423                         /* no need to apply CO-RE relocation if the program is
6424                          * not going to be loaded
6425                          */
6426                         if (!prog->load)
6427                                 continue;
6428
6429                         err = bpf_core_apply_relo(prog, rec, i, obj->btf, cand_cache);
6430                         if (err) {
6431                                 pr_warn("prog '%s': relo #%d: failed to relocate: %d\n",
6432                                         prog->name, i, err);
6433                                 goto out;
6434                         }
6435                 }
6436         }
6437
6438 out:
6439         /* obj->btf_vmlinux and module BTFs are freed after object load */
6440         btf__free(obj->btf_vmlinux_override);
6441         obj->btf_vmlinux_override = NULL;
6442
6443         if (!IS_ERR_OR_NULL(cand_cache)) {
6444                 hashmap__for_each_entry(cand_cache, entry, i) {
6445                         bpf_core_free_cands(entry->value);
6446                 }
6447                 hashmap__free(cand_cache);
6448         }
6449         return err;
6450 }
6451
6452 /* Relocate data references within program code:
6453  *  - map references;
6454  *  - global variable references;
6455  *  - extern references.
6456  */
6457 static int
6458 bpf_object__relocate_data(struct bpf_object *obj, struct bpf_program *prog)
6459 {
6460         int i;
6461
6462         for (i = 0; i < prog->nr_reloc; i++) {
6463                 struct reloc_desc *relo = &prog->reloc_desc[i];
6464                 struct bpf_insn *insn = &prog->insns[relo->insn_idx];
6465                 struct extern_desc *ext;
6466
6467                 switch (relo->type) {
6468                 case RELO_LD64:
6469                         if (obj->gen_loader) {
6470                                 insn[0].src_reg = BPF_PSEUDO_MAP_IDX;
6471                                 insn[0].imm = relo->map_idx;
6472                         } else {
6473                                 insn[0].src_reg = BPF_PSEUDO_MAP_FD;
6474                                 insn[0].imm = obj->maps[relo->map_idx].fd;
6475                         }
6476                         break;
6477                 case RELO_DATA:
6478                         insn[1].imm = insn[0].imm + relo->sym_off;
6479                         if (obj->gen_loader) {
6480                                 insn[0].src_reg = BPF_PSEUDO_MAP_IDX_VALUE;
6481                                 insn[0].imm = relo->map_idx;
6482                         } else {
6483                                 insn[0].src_reg = BPF_PSEUDO_MAP_VALUE;
6484                                 insn[0].imm = obj->maps[relo->map_idx].fd;
6485                         }
6486                         break;
6487                 case RELO_EXTERN_VAR:
6488                         ext = &obj->externs[relo->sym_off];
6489                         if (ext->type == EXT_KCFG) {
6490                                 if (obj->gen_loader) {
6491                                         insn[0].src_reg = BPF_PSEUDO_MAP_IDX_VALUE;
6492                                         insn[0].imm = obj->kconfig_map_idx;
6493                                 } else {
6494                                         insn[0].src_reg = BPF_PSEUDO_MAP_VALUE;
6495                                         insn[0].imm = obj->maps[obj->kconfig_map_idx].fd;
6496                                 }
6497                                 insn[1].imm = ext->kcfg.data_off;
6498                         } else /* EXT_KSYM */ {
6499                                 if (ext->ksym.type_id) { /* typed ksyms */
6500                                         insn[0].src_reg = BPF_PSEUDO_BTF_ID;
6501                                         insn[0].imm = ext->ksym.kernel_btf_id;
6502                                         insn[1].imm = ext->ksym.kernel_btf_obj_fd;
6503                                 } else { /* typeless ksyms */
6504                                         insn[0].imm = (__u32)ext->ksym.addr;
6505                                         insn[1].imm = ext->ksym.addr >> 32;
6506                                 }
6507                         }
6508                         break;
6509                 case RELO_EXTERN_FUNC:
6510                         ext = &obj->externs[relo->sym_off];
6511                         insn[0].src_reg = BPF_PSEUDO_KFUNC_CALL;
6512                         insn[0].imm = ext->ksym.kernel_btf_id;
6513                         break;
6514                 case RELO_SUBPROG_ADDR:
6515                         if (insn[0].src_reg != BPF_PSEUDO_FUNC) {
6516                                 pr_warn("prog '%s': relo #%d: bad insn\n",
6517                                         prog->name, i);
6518                                 return -EINVAL;
6519                         }
6520                         /* handled already */
6521                         break;
6522                 case RELO_CALL:
6523                         /* handled already */
6524                         break;
6525                 default:
6526                         pr_warn("prog '%s': relo #%d: bad relo type %d\n",
6527                                 prog->name, i, relo->type);
6528                         return -EINVAL;
6529                 }
6530         }
6531
6532         return 0;
6533 }
6534
6535 static int adjust_prog_btf_ext_info(const struct bpf_object *obj,
6536                                     const struct bpf_program *prog,
6537                                     const struct btf_ext_info *ext_info,
6538                                     void **prog_info, __u32 *prog_rec_cnt,
6539                                     __u32 *prog_rec_sz)
6540 {
6541         void *copy_start = NULL, *copy_end = NULL;
6542         void *rec, *rec_end, *new_prog_info;
6543         const struct btf_ext_info_sec *sec;
6544         size_t old_sz, new_sz;
6545         const char *sec_name;
6546         int i, off_adj;
6547
6548         for_each_btf_ext_sec(ext_info, sec) {
6549                 sec_name = btf__name_by_offset(obj->btf, sec->sec_name_off);
6550                 if (!sec_name)
6551                         return -EINVAL;
6552                 if (strcmp(sec_name, prog->sec_name) != 0)
6553                         continue;
6554
6555                 for_each_btf_ext_rec(ext_info, sec, i, rec) {
6556                         __u32 insn_off = *(__u32 *)rec / BPF_INSN_SZ;
6557
6558                         if (insn_off < prog->sec_insn_off)
6559                                 continue;
6560                         if (insn_off >= prog->sec_insn_off + prog->sec_insn_cnt)
6561                                 break;
6562
6563                         if (!copy_start)
6564                                 copy_start = rec;
6565                         copy_end = rec + ext_info->rec_size;
6566                 }
6567
6568                 if (!copy_start)
6569                         return -ENOENT;
6570
6571                 /* append func/line info of a given (sub-)program to the main
6572                  * program func/line info
6573                  */
6574                 old_sz = (size_t)(*prog_rec_cnt) * ext_info->rec_size;
6575                 new_sz = old_sz + (copy_end - copy_start);
6576                 new_prog_info = realloc(*prog_info, new_sz);
6577                 if (!new_prog_info)
6578                         return -ENOMEM;
6579                 *prog_info = new_prog_info;
6580                 *prog_rec_cnt = new_sz / ext_info->rec_size;
6581                 memcpy(new_prog_info + old_sz, copy_start, copy_end - copy_start);
6582
6583                 /* Kernel instruction offsets are in units of 8-byte
6584                  * instructions, while .BTF.ext instruction offsets generated
6585                  * by Clang are in units of bytes. So convert Clang offsets
6586                  * into kernel offsets and adjust offset according to program
6587                  * relocated position.
6588                  */
6589                 off_adj = prog->sub_insn_off - prog->sec_insn_off;
6590                 rec = new_prog_info + old_sz;
6591                 rec_end = new_prog_info + new_sz;
6592                 for (; rec < rec_end; rec += ext_info->rec_size) {
6593                         __u32 *insn_off = rec;
6594
6595                         *insn_off = *insn_off / BPF_INSN_SZ + off_adj;
6596                 }
6597                 *prog_rec_sz = ext_info->rec_size;
6598                 return 0;
6599         }
6600
6601         return -ENOENT;
6602 }
6603
6604 static int
6605 reloc_prog_func_and_line_info(const struct bpf_object *obj,
6606                               struct bpf_program *main_prog,
6607                               const struct bpf_program *prog)
6608 {
6609         int err;
6610
6611         /* no .BTF.ext relocation if .BTF.ext is missing or kernel doesn't
6612          * supprot func/line info
6613          */
6614         if (!obj->btf_ext || !kernel_supports(obj, FEAT_BTF_FUNC))
6615                 return 0;
6616
6617         /* only attempt func info relocation if main program's func_info
6618          * relocation was successful
6619          */
6620         if (main_prog != prog && !main_prog->func_info)
6621                 goto line_info;
6622
6623         err = adjust_prog_btf_ext_info(obj, prog, &obj->btf_ext->func_info,
6624                                        &main_prog->func_info,
6625                                        &main_prog->func_info_cnt,
6626                                        &main_prog->func_info_rec_size);
6627         if (err) {
6628                 if (err != -ENOENT) {
6629                         pr_warn("prog '%s': error relocating .BTF.ext function info: %d\n",
6630                                 prog->name, err);
6631                         return err;
6632                 }
6633                 if (main_prog->func_info) {
6634                         /*
6635                          * Some info has already been found but has problem
6636                          * in the last btf_ext reloc. Must have to error out.
6637                          */
6638                         pr_warn("prog '%s': missing .BTF.ext function info.\n", prog->name);
6639                         return err;
6640                 }
6641                 /* Have problem loading the very first info. Ignore the rest. */
6642                 pr_warn("prog '%s': missing .BTF.ext function info for the main program, skipping all of .BTF.ext func info.\n",
6643                         prog->name);
6644         }
6645
6646 line_info:
6647         /* don't relocate line info if main program's relocation failed */
6648         if (main_prog != prog && !main_prog->line_info)
6649                 return 0;
6650
6651         err = adjust_prog_btf_ext_info(obj, prog, &obj->btf_ext->line_info,
6652                                        &main_prog->line_info,
6653                                        &main_prog->line_info_cnt,
6654                                        &main_prog->line_info_rec_size);
6655         if (err) {
6656                 if (err != -ENOENT) {
6657                         pr_warn("prog '%s': error relocating .BTF.ext line info: %d\n",
6658                                 prog->name, err);
6659                         return err;
6660                 }
6661                 if (main_prog->line_info) {
6662                         /*
6663                          * Some info has already been found but has problem
6664                          * in the last btf_ext reloc. Must have to error out.
6665                          */
6666                         pr_warn("prog '%s': missing .BTF.ext line info.\n", prog->name);
6667                         return err;
6668                 }
6669                 /* Have problem loading the very first info. Ignore the rest. */
6670                 pr_warn("prog '%s': missing .BTF.ext line info for the main program, skipping all of .BTF.ext line info.\n",
6671                         prog->name);
6672         }
6673         return 0;
6674 }
6675
6676 static int cmp_relo_by_insn_idx(const void *key, const void *elem)
6677 {
6678         size_t insn_idx = *(const size_t *)key;
6679         const struct reloc_desc *relo = elem;
6680
6681         if (insn_idx == relo->insn_idx)
6682                 return 0;
6683         return insn_idx < relo->insn_idx ? -1 : 1;
6684 }
6685
6686 static struct reloc_desc *find_prog_insn_relo(const struct bpf_program *prog, size_t insn_idx)
6687 {
6688         return bsearch(&insn_idx, prog->reloc_desc, prog->nr_reloc,
6689                        sizeof(*prog->reloc_desc), cmp_relo_by_insn_idx);
6690 }
6691
6692 static int append_subprog_relos(struct bpf_program *main_prog, struct bpf_program *subprog)
6693 {
6694         int new_cnt = main_prog->nr_reloc + subprog->nr_reloc;
6695         struct reloc_desc *relos;
6696         int i;
6697
6698         if (main_prog == subprog)
6699                 return 0;
6700         relos = libbpf_reallocarray(main_prog->reloc_desc, new_cnt, sizeof(*relos));
6701         if (!relos)
6702                 return -ENOMEM;
6703         memcpy(relos + main_prog->nr_reloc, subprog->reloc_desc,
6704                sizeof(*relos) * subprog->nr_reloc);
6705
6706         for (i = main_prog->nr_reloc; i < new_cnt; i++)
6707                 relos[i].insn_idx += subprog->sub_insn_off;
6708         /* After insn_idx adjustment the 'relos' array is still sorted
6709          * by insn_idx and doesn't break bsearch.
6710          */
6711         main_prog->reloc_desc = relos;
6712         main_prog->nr_reloc = new_cnt;
6713         return 0;
6714 }
6715
6716 static int
6717 bpf_object__reloc_code(struct bpf_object *obj, struct bpf_program *main_prog,
6718                        struct bpf_program *prog)
6719 {
6720         size_t sub_insn_idx, insn_idx, new_cnt;
6721         struct bpf_program *subprog;
6722         struct bpf_insn *insns, *insn;
6723         struct reloc_desc *relo;
6724         int err;
6725
6726         err = reloc_prog_func_and_line_info(obj, main_prog, prog);
6727         if (err)
6728                 return err;
6729
6730         for (insn_idx = 0; insn_idx < prog->sec_insn_cnt; insn_idx++) {
6731                 insn = &main_prog->insns[prog->sub_insn_off + insn_idx];
6732                 if (!insn_is_subprog_call(insn) && !insn_is_pseudo_func(insn))
6733                         continue;
6734
6735                 relo = find_prog_insn_relo(prog, insn_idx);
6736                 if (relo && relo->type == RELO_EXTERN_FUNC)
6737                         /* kfunc relocations will be handled later
6738                          * in bpf_object__relocate_data()
6739                          */
6740                         continue;
6741                 if (relo && relo->type != RELO_CALL && relo->type != RELO_SUBPROG_ADDR) {
6742                         pr_warn("prog '%s': unexpected relo for insn #%zu, type %d\n",
6743                                 prog->name, insn_idx, relo->type);
6744                         return -LIBBPF_ERRNO__RELOC;
6745                 }
6746                 if (relo) {
6747                         /* sub-program instruction index is a combination of
6748                          * an offset of a symbol pointed to by relocation and
6749                          * call instruction's imm field; for global functions,
6750                          * call always has imm = -1, but for static functions
6751                          * relocation is against STT_SECTION and insn->imm
6752                          * points to a start of a static function
6753                          *
6754                          * for subprog addr relocation, the relo->sym_off + insn->imm is
6755                          * the byte offset in the corresponding section.
6756                          */
6757                         if (relo->type == RELO_CALL)
6758                                 sub_insn_idx = relo->sym_off / BPF_INSN_SZ + insn->imm + 1;
6759                         else
6760                                 sub_insn_idx = (relo->sym_off + insn->imm) / BPF_INSN_SZ;
6761                 } else if (insn_is_pseudo_func(insn)) {
6762                         /*
6763                          * RELO_SUBPROG_ADDR relo is always emitted even if both
6764                          * functions are in the same section, so it shouldn't reach here.
6765                          */
6766                         pr_warn("prog '%s': missing subprog addr relo for insn #%zu\n",
6767                                 prog->name, insn_idx);
6768                         return -LIBBPF_ERRNO__RELOC;
6769                 } else {
6770                         /* if subprogram call is to a static function within
6771                          * the same ELF section, there won't be any relocation
6772                          * emitted, but it also means there is no additional
6773                          * offset necessary, insns->imm is relative to
6774                          * instruction's original position within the section
6775                          */
6776                         sub_insn_idx = prog->sec_insn_off + insn_idx + insn->imm + 1;
6777                 }
6778
6779                 /* we enforce that sub-programs should be in .text section */
6780                 subprog = find_prog_by_sec_insn(obj, obj->efile.text_shndx, sub_insn_idx);
6781                 if (!subprog) {
6782                         pr_warn("prog '%s': no .text section found yet sub-program call exists\n",
6783                                 prog->name);
6784                         return -LIBBPF_ERRNO__RELOC;
6785                 }
6786
6787                 /* if it's the first call instruction calling into this
6788                  * subprogram (meaning this subprog hasn't been processed
6789                  * yet) within the context of current main program:
6790                  *   - append it at the end of main program's instructions blog;
6791                  *   - process is recursively, while current program is put on hold;
6792                  *   - if that subprogram calls some other not yet processes
6793                  *   subprogram, same thing will happen recursively until
6794                  *   there are no more unprocesses subprograms left to append
6795                  *   and relocate.
6796                  */
6797                 if (subprog->sub_insn_off == 0) {
6798                         subprog->sub_insn_off = main_prog->insns_cnt;
6799
6800                         new_cnt = main_prog->insns_cnt + subprog->insns_cnt;
6801                         insns = libbpf_reallocarray(main_prog->insns, new_cnt, sizeof(*insns));
6802                         if (!insns) {
6803                                 pr_warn("prog '%s': failed to realloc prog code\n", main_prog->name);
6804                                 return -ENOMEM;
6805                         }
6806                         main_prog->insns = insns;
6807                         main_prog->insns_cnt = new_cnt;
6808
6809                         memcpy(main_prog->insns + subprog->sub_insn_off, subprog->insns,
6810                                subprog->insns_cnt * sizeof(*insns));
6811
6812                         pr_debug("prog '%s': added %zu insns from sub-prog '%s'\n",
6813                                  main_prog->name, subprog->insns_cnt, subprog->name);
6814
6815                         /* The subprog insns are now appended. Append its relos too. */
6816                         err = append_subprog_relos(main_prog, subprog);
6817                         if (err)
6818                                 return err;
6819                         err = bpf_object__reloc_code(obj, main_prog, subprog);
6820                         if (err)
6821                                 return err;
6822                 }
6823
6824                 /* main_prog->insns memory could have been re-allocated, so
6825                  * calculate pointer again
6826                  */
6827                 insn = &main_prog->insns[prog->sub_insn_off + insn_idx];
6828                 /* calculate correct instruction position within current main
6829                  * prog; each main prog can have a different set of
6830                  * subprograms appended (potentially in different order as
6831                  * well), so position of any subprog can be different for
6832                  * different main programs */
6833                 insn->imm = subprog->sub_insn_off - (prog->sub_insn_off + insn_idx) - 1;
6834
6835                 pr_debug("prog '%s': insn #%zu relocated, imm %d points to subprog '%s' (now at %zu offset)\n",
6836                          prog->name, insn_idx, insn->imm, subprog->name, subprog->sub_insn_off);
6837         }
6838
6839         return 0;
6840 }
6841
6842 /*
6843  * Relocate sub-program calls.
6844  *
6845  * Algorithm operates as follows. Each entry-point BPF program (referred to as
6846  * main prog) is processed separately. For each subprog (non-entry functions,
6847  * that can be called from either entry progs or other subprogs) gets their
6848  * sub_insn_off reset to zero. This serves as indicator that this subprogram
6849  * hasn't been yet appended and relocated within current main prog. Once its
6850  * relocated, sub_insn_off will point at the position within current main prog
6851  * where given subprog was appended. This will further be used to relocate all
6852  * the call instructions jumping into this subprog.
6853  *
6854  * We start with main program and process all call instructions. If the call
6855  * is into a subprog that hasn't been processed (i.e., subprog->sub_insn_off
6856  * is zero), subprog instructions are appended at the end of main program's
6857  * instruction array. Then main program is "put on hold" while we recursively
6858  * process newly appended subprogram. If that subprogram calls into another
6859  * subprogram that hasn't been appended, new subprogram is appended again to
6860  * the *main* prog's instructions (subprog's instructions are always left
6861  * untouched, as they need to be in unmodified state for subsequent main progs
6862  * and subprog instructions are always sent only as part of a main prog) and
6863  * the process continues recursively. Once all the subprogs called from a main
6864  * prog or any of its subprogs are appended (and relocated), all their
6865  * positions within finalized instructions array are known, so it's easy to
6866  * rewrite call instructions with correct relative offsets, corresponding to
6867  * desired target subprog.
6868  *
6869  * Its important to realize that some subprogs might not be called from some
6870  * main prog and any of its called/used subprogs. Those will keep their
6871  * subprog->sub_insn_off as zero at all times and won't be appended to current
6872  * main prog and won't be relocated within the context of current main prog.
6873  * They might still be used from other main progs later.
6874  *
6875  * Visually this process can be shown as below. Suppose we have two main
6876  * programs mainA and mainB and BPF object contains three subprogs: subA,
6877  * subB, and subC. mainA calls only subA, mainB calls only subC, but subA and
6878  * subC both call subB:
6879  *
6880  *        +--------+ +-------+
6881  *        |        v v       |
6882  *     +--+---+ +--+-+-+ +---+--+
6883  *     | subA | | subB | | subC |
6884  *     +--+---+ +------+ +---+--+
6885  *        ^                  ^
6886  *        |                  |
6887  *    +---+-------+   +------+----+
6888  *    |   mainA   |   |   mainB   |
6889  *    +-----------+   +-----------+
6890  *
6891  * We'll start relocating mainA, will find subA, append it and start
6892  * processing sub A recursively:
6893  *
6894  *    +-----------+------+
6895  *    |   mainA   | subA |
6896  *    +-----------+------+
6897  *
6898  * At this point we notice that subB is used from subA, so we append it and
6899  * relocate (there are no further subcalls from subB):
6900  *
6901  *    +-----------+------+------+
6902  *    |   mainA   | subA | subB |
6903  *    +-----------+------+------+
6904  *
6905  * At this point, we relocate subA calls, then go one level up and finish with
6906  * relocatin mainA calls. mainA is done.
6907  *
6908  * For mainB process is similar but results in different order. We start with
6909  * mainB and skip subA and subB, as mainB never calls them (at least
6910  * directly), but we see subC is needed, so we append and start processing it:
6911  *
6912  *    +-----------+------+
6913  *    |   mainB   | subC |
6914  *    +-----------+------+
6915  * Now we see subC needs subB, so we go back to it, append and relocate it:
6916  *
6917  *    +-----------+------+------+
6918  *    |   mainB   | subC | subB |
6919  *    +-----------+------+------+
6920  *
6921  * At this point we unwind recursion, relocate calls in subC, then in mainB.
6922  */
6923 static int
6924 bpf_object__relocate_calls(struct bpf_object *obj, struct bpf_program *prog)
6925 {
6926         struct bpf_program *subprog;
6927         int i, err;
6928
6929         /* mark all subprogs as not relocated (yet) within the context of
6930          * current main program
6931          */
6932         for (i = 0; i < obj->nr_programs; i++) {
6933                 subprog = &obj->programs[i];
6934                 if (!prog_is_subprog(obj, subprog))
6935                         continue;
6936
6937                 subprog->sub_insn_off = 0;
6938         }
6939
6940         err = bpf_object__reloc_code(obj, prog, prog);
6941         if (err)
6942                 return err;
6943
6944
6945         return 0;
6946 }
6947
6948 static void
6949 bpf_object__free_relocs(struct bpf_object *obj)
6950 {
6951         struct bpf_program *prog;
6952         int i;
6953
6954         /* free up relocation descriptors */
6955         for (i = 0; i < obj->nr_programs; i++) {
6956                 prog = &obj->programs[i];
6957                 zfree(&prog->reloc_desc);
6958                 prog->nr_reloc = 0;
6959         }
6960 }
6961
6962 static int
6963 bpf_object__relocate(struct bpf_object *obj, const char *targ_btf_path)
6964 {
6965         struct bpf_program *prog;
6966         size_t i, j;
6967         int err;
6968
6969         if (obj->btf_ext) {
6970                 err = bpf_object__relocate_core(obj, targ_btf_path);
6971                 if (err) {
6972                         pr_warn("failed to perform CO-RE relocations: %d\n",
6973                                 err);
6974                         return err;
6975                 }
6976         }
6977
6978         /* Before relocating calls pre-process relocations and mark
6979          * few ld_imm64 instructions that points to subprogs.
6980          * Otherwise bpf_object__reloc_code() later would have to consider
6981          * all ld_imm64 insns as relocation candidates. That would
6982          * reduce relocation speed, since amount of find_prog_insn_relo()
6983          * would increase and most of them will fail to find a relo.
6984          */
6985         for (i = 0; i < obj->nr_programs; i++) {
6986                 prog = &obj->programs[i];
6987                 for (j = 0; j < prog->nr_reloc; j++) {
6988                         struct reloc_desc *relo = &prog->reloc_desc[j];
6989                         struct bpf_insn *insn = &prog->insns[relo->insn_idx];
6990
6991                         /* mark the insn, so it's recognized by insn_is_pseudo_func() */
6992                         if (relo->type == RELO_SUBPROG_ADDR)
6993                                 insn[0].src_reg = BPF_PSEUDO_FUNC;
6994                 }
6995         }
6996
6997         /* relocate subprogram calls and append used subprograms to main
6998          * programs; each copy of subprogram code needs to be relocated
6999          * differently for each main program, because its code location might
7000          * have changed.
7001          * Append subprog relos to main programs to allow data relos to be
7002          * processed after text is completely relocated.
7003          */
7004         for (i = 0; i < obj->nr_programs; i++) {
7005                 prog = &obj->programs[i];
7006                 /* sub-program's sub-calls are relocated within the context of
7007                  * its main program only
7008                  */
7009                 if (prog_is_subprog(obj, prog))
7010                         continue;
7011
7012                 err = bpf_object__relocate_calls(obj, prog);
7013                 if (err) {
7014                         pr_warn("prog '%s': failed to relocate calls: %d\n",
7015                                 prog->name, err);
7016                         return err;
7017                 }
7018         }
7019         /* Process data relos for main programs */
7020         for (i = 0; i < obj->nr_programs; i++) {
7021                 prog = &obj->programs[i];
7022                 if (prog_is_subprog(obj, prog))
7023                         continue;
7024                 err = bpf_object__relocate_data(obj, prog);
7025                 if (err) {
7026                         pr_warn("prog '%s': failed to relocate data references: %d\n",
7027                                 prog->name, err);
7028                         return err;
7029                 }
7030         }
7031         if (!obj->gen_loader)
7032                 bpf_object__free_relocs(obj);
7033         return 0;
7034 }
7035
7036 static int bpf_object__collect_st_ops_relos(struct bpf_object *obj,
7037                                             GElf_Shdr *shdr, Elf_Data *data);
7038
7039 static int bpf_object__collect_map_relos(struct bpf_object *obj,
7040                                          GElf_Shdr *shdr, Elf_Data *data)
7041 {
7042         const int bpf_ptr_sz = 8, host_ptr_sz = sizeof(void *);
7043         int i, j, nrels, new_sz;
7044         const struct btf_var_secinfo *vi = NULL;
7045         const struct btf_type *sec, *var, *def;
7046         struct bpf_map *map = NULL, *targ_map;
7047         const struct btf_member *member;
7048         const char *name, *mname;
7049         Elf_Data *symbols;
7050         unsigned int moff;
7051         GElf_Sym sym;
7052         GElf_Rel rel;
7053         void *tmp;
7054
7055         if (!obj->efile.btf_maps_sec_btf_id || !obj->btf)
7056                 return -EINVAL;
7057         sec = btf__type_by_id(obj->btf, obj->efile.btf_maps_sec_btf_id);
7058         if (!sec)
7059                 return -EINVAL;
7060
7061         symbols = obj->efile.symbols;
7062         nrels = shdr->sh_size / shdr->sh_entsize;
7063         for (i = 0; i < nrels; i++) {
7064                 if (!gelf_getrel(data, i, &rel)) {
7065                         pr_warn(".maps relo #%d: failed to get ELF relo\n", i);
7066                         return -LIBBPF_ERRNO__FORMAT;
7067                 }
7068                 if (!gelf_getsym(symbols, GELF_R_SYM(rel.r_info), &sym)) {
7069                         pr_warn(".maps relo #%d: symbol %zx not found\n",
7070                                 i, (size_t)GELF_R_SYM(rel.r_info));
7071                         return -LIBBPF_ERRNO__FORMAT;
7072                 }
7073                 name = elf_sym_str(obj, sym.st_name) ?: "<?>";
7074                 if (sym.st_shndx != obj->efile.btf_maps_shndx) {
7075                         pr_warn(".maps relo #%d: '%s' isn't a BTF-defined map\n",
7076                                 i, name);
7077                         return -LIBBPF_ERRNO__RELOC;
7078                 }
7079
7080                 pr_debug(".maps relo #%d: for %zd value %zd rel.r_offset %zu name %d ('%s')\n",
7081                          i, (ssize_t)(rel.r_info >> 32), (size_t)sym.st_value,
7082                          (size_t)rel.r_offset, sym.st_name, name);
7083
7084                 for (j = 0; j < obj->nr_maps; j++) {
7085                         map = &obj->maps[j];
7086                         if (map->sec_idx != obj->efile.btf_maps_shndx)
7087                                 continue;
7088
7089                         vi = btf_var_secinfos(sec) + map->btf_var_idx;
7090                         if (vi->offset <= rel.r_offset &&
7091                             rel.r_offset + bpf_ptr_sz <= vi->offset + vi->size)
7092                                 break;
7093                 }
7094                 if (j == obj->nr_maps) {
7095                         pr_warn(".maps relo #%d: cannot find map '%s' at rel.r_offset %zu\n",
7096                                 i, name, (size_t)rel.r_offset);
7097                         return -EINVAL;
7098                 }
7099
7100                 if (!bpf_map_type__is_map_in_map(map->def.type))
7101                         return -EINVAL;
7102                 if (map->def.type == BPF_MAP_TYPE_HASH_OF_MAPS &&
7103                     map->def.key_size != sizeof(int)) {
7104                         pr_warn(".maps relo #%d: hash-of-maps '%s' should have key size %zu.\n",
7105                                 i, map->name, sizeof(int));
7106                         return -EINVAL;
7107                 }
7108
7109                 targ_map = bpf_object__find_map_by_name(obj, name);
7110                 if (!targ_map)
7111                         return -ESRCH;
7112
7113                 var = btf__type_by_id(obj->btf, vi->type);
7114                 def = skip_mods_and_typedefs(obj->btf, var->type, NULL);
7115                 if (btf_vlen(def) == 0)
7116                         return -EINVAL;
7117                 member = btf_members(def) + btf_vlen(def) - 1;
7118                 mname = btf__name_by_offset(obj->btf, member->name_off);
7119                 if (strcmp(mname, "values"))
7120                         return -EINVAL;
7121
7122                 moff = btf_member_bit_offset(def, btf_vlen(def) - 1) / 8;
7123                 if (rel.r_offset - vi->offset < moff)
7124                         return -EINVAL;
7125
7126                 moff = rel.r_offset - vi->offset - moff;
7127                 /* here we use BPF pointer size, which is always 64 bit, as we
7128                  * are parsing ELF that was built for BPF target
7129                  */
7130                 if (moff % bpf_ptr_sz)
7131                         return -EINVAL;
7132                 moff /= bpf_ptr_sz;
7133                 if (moff >= map->init_slots_sz) {
7134                         new_sz = moff + 1;
7135                         tmp = libbpf_reallocarray(map->init_slots, new_sz, host_ptr_sz);
7136                         if (!tmp)
7137                                 return -ENOMEM;
7138                         map->init_slots = tmp;
7139                         memset(map->init_slots + map->init_slots_sz, 0,
7140                                (new_sz - map->init_slots_sz) * host_ptr_sz);
7141                         map->init_slots_sz = new_sz;
7142                 }
7143                 map->init_slots[moff] = targ_map;
7144
7145                 pr_debug(".maps relo #%d: map '%s' slot [%d] points to map '%s'\n",
7146                          i, map->name, moff, name);
7147         }
7148
7149         return 0;
7150 }
7151
7152 static int cmp_relocs(const void *_a, const void *_b)
7153 {
7154         const struct reloc_desc *a = _a;
7155         const struct reloc_desc *b = _b;
7156
7157         if (a->insn_idx != b->insn_idx)
7158                 return a->insn_idx < b->insn_idx ? -1 : 1;
7159
7160         /* no two relocations should have the same insn_idx, but ... */
7161         if (a->type != b->type)
7162                 return a->type < b->type ? -1 : 1;
7163
7164         return 0;
7165 }
7166
7167 static int bpf_object__collect_relos(struct bpf_object *obj)
7168 {
7169         int i, err;
7170
7171         for (i = 0; i < obj->efile.nr_reloc_sects; i++) {
7172                 GElf_Shdr *shdr = &obj->efile.reloc_sects[i].shdr;
7173                 Elf_Data *data = obj->efile.reloc_sects[i].data;
7174                 int idx = shdr->sh_info;
7175
7176                 if (shdr->sh_type != SHT_REL) {
7177                         pr_warn("internal error at %d\n", __LINE__);
7178                         return -LIBBPF_ERRNO__INTERNAL;
7179                 }
7180
7181                 if (idx == obj->efile.st_ops_shndx)
7182                         err = bpf_object__collect_st_ops_relos(obj, shdr, data);
7183                 else if (idx == obj->efile.btf_maps_shndx)
7184                         err = bpf_object__collect_map_relos(obj, shdr, data);
7185                 else
7186                         err = bpf_object__collect_prog_relos(obj, shdr, data);
7187                 if (err)
7188                         return err;
7189         }
7190
7191         for (i = 0; i < obj->nr_programs; i++) {
7192                 struct bpf_program *p = &obj->programs[i];
7193
7194                 if (!p->nr_reloc)
7195                         continue;
7196
7197                 qsort(p->reloc_desc, p->nr_reloc, sizeof(*p->reloc_desc), cmp_relocs);
7198         }
7199         return 0;
7200 }
7201
7202 static bool insn_is_helper_call(struct bpf_insn *insn, enum bpf_func_id *func_id)
7203 {
7204         if (BPF_CLASS(insn->code) == BPF_JMP &&
7205             BPF_OP(insn->code) == BPF_CALL &&
7206             BPF_SRC(insn->code) == BPF_K &&
7207             insn->src_reg == 0 &&
7208             insn->dst_reg == 0) {
7209                     *func_id = insn->imm;
7210                     return true;
7211         }
7212         return false;
7213 }
7214
7215 static int bpf_object__sanitize_prog(struct bpf_object *obj, struct bpf_program *prog)
7216 {
7217         struct bpf_insn *insn = prog->insns;
7218         enum bpf_func_id func_id;
7219         int i;
7220
7221         if (obj->gen_loader)
7222                 return 0;
7223
7224         for (i = 0; i < prog->insns_cnt; i++, insn++) {
7225                 if (!insn_is_helper_call(insn, &func_id))
7226                         continue;
7227
7228                 /* on kernels that don't yet support
7229                  * bpf_probe_read_{kernel,user}[_str] helpers, fall back
7230                  * to bpf_probe_read() which works well for old kernels
7231                  */
7232                 switch (func_id) {
7233                 case BPF_FUNC_probe_read_kernel:
7234                 case BPF_FUNC_probe_read_user:
7235                         if (!kernel_supports(obj, FEAT_PROBE_READ_KERN))
7236                                 insn->imm = BPF_FUNC_probe_read;
7237                         break;
7238                 case BPF_FUNC_probe_read_kernel_str:
7239                 case BPF_FUNC_probe_read_user_str:
7240                         if (!kernel_supports(obj, FEAT_PROBE_READ_KERN))
7241                                 insn->imm = BPF_FUNC_probe_read_str;
7242                         break;
7243                 default:
7244                         break;
7245                 }
7246         }
7247         return 0;
7248 }
7249
7250 static int
7251 load_program(struct bpf_program *prog, struct bpf_insn *insns, int insns_cnt,
7252              char *license, __u32 kern_version, int *pfd)
7253 {
7254         struct bpf_prog_load_params load_attr = {};
7255         char *cp, errmsg[STRERR_BUFSIZE];
7256         size_t log_buf_size = 0;
7257         char *log_buf = NULL;
7258         int btf_fd, ret;
7259
7260         if (prog->type == BPF_PROG_TYPE_UNSPEC) {
7261                 /*
7262                  * The program type must be set.  Most likely we couldn't find a proper
7263                  * section definition at load time, and thus we didn't infer the type.
7264                  */
7265                 pr_warn("prog '%s': missing BPF prog type, check ELF section name '%s'\n",
7266                         prog->name, prog->sec_name);
7267                 return -EINVAL;
7268         }
7269
7270         if (!insns || !insns_cnt)
7271                 return -EINVAL;
7272
7273         load_attr.prog_type = prog->type;
7274         /* old kernels might not support specifying expected_attach_type */
7275         if (!kernel_supports(prog->obj, FEAT_EXP_ATTACH_TYPE) && prog->sec_def &&
7276             prog->sec_def->is_exp_attach_type_optional)
7277                 load_attr.expected_attach_type = 0;
7278         else
7279                 load_attr.expected_attach_type = prog->expected_attach_type;
7280         if (kernel_supports(prog->obj, FEAT_PROG_NAME))
7281                 load_attr.name = prog->name;
7282         load_attr.insns = insns;
7283         load_attr.insn_cnt = insns_cnt;
7284         load_attr.license = license;
7285         load_attr.attach_btf_id = prog->attach_btf_id;
7286         if (prog->attach_prog_fd)
7287                 load_attr.attach_prog_fd = prog->attach_prog_fd;
7288         else
7289                 load_attr.attach_btf_obj_fd = prog->attach_btf_obj_fd;
7290         load_attr.attach_btf_id = prog->attach_btf_id;
7291         load_attr.kern_version = kern_version;
7292         load_attr.prog_ifindex = prog->prog_ifindex;
7293
7294         /* specify func_info/line_info only if kernel supports them */
7295         btf_fd = bpf_object__btf_fd(prog->obj);
7296         if (btf_fd >= 0 && kernel_supports(prog->obj, FEAT_BTF_FUNC)) {
7297                 load_attr.prog_btf_fd = btf_fd;
7298                 load_attr.func_info = prog->func_info;
7299                 load_attr.func_info_rec_size = prog->func_info_rec_size;
7300                 load_attr.func_info_cnt = prog->func_info_cnt;
7301                 load_attr.line_info = prog->line_info;
7302                 load_attr.line_info_rec_size = prog->line_info_rec_size;
7303                 load_attr.line_info_cnt = prog->line_info_cnt;
7304         }
7305         load_attr.log_level = prog->log_level;
7306         load_attr.prog_flags = prog->prog_flags;
7307
7308         if (prog->obj->gen_loader) {
7309                 bpf_gen__prog_load(prog->obj->gen_loader, &load_attr,
7310                                    prog - prog->obj->programs);
7311                 *pfd = -1;
7312                 return 0;
7313         }
7314 retry_load:
7315         if (log_buf_size) {
7316                 log_buf = malloc(log_buf_size);
7317                 if (!log_buf)
7318                         return -ENOMEM;
7319
7320                 *log_buf = 0;
7321         }
7322
7323         load_attr.log_buf = log_buf;
7324         load_attr.log_buf_sz = log_buf_size;
7325         ret = libbpf__bpf_prog_load(&load_attr);
7326
7327         if (ret >= 0) {
7328                 if (log_buf && load_attr.log_level)
7329                         pr_debug("verifier log:\n%s", log_buf);
7330
7331                 if (prog->obj->rodata_map_idx >= 0 &&
7332                     kernel_supports(prog->obj, FEAT_PROG_BIND_MAP)) {
7333                         struct bpf_map *rodata_map =
7334                                 &prog->obj->maps[prog->obj->rodata_map_idx];
7335
7336                         if (bpf_prog_bind_map(ret, bpf_map__fd(rodata_map), NULL)) {
7337                                 cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg));
7338                                 pr_warn("prog '%s': failed to bind .rodata map: %s\n",
7339                                         prog->name, cp);
7340                                 /* Don't fail hard if can't bind rodata. */
7341                         }
7342                 }
7343
7344                 *pfd = ret;
7345                 ret = 0;
7346                 goto out;
7347         }
7348
7349         if (!log_buf || errno == ENOSPC) {
7350                 log_buf_size = max((size_t)BPF_LOG_BUF_SIZE,
7351                                    log_buf_size << 1);
7352
7353                 free(log_buf);
7354                 goto retry_load;
7355         }
7356         ret = errno ? -errno : -LIBBPF_ERRNO__LOAD;
7357         cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg));
7358         pr_warn("load bpf program failed: %s\n", cp);
7359         pr_perm_msg(ret);
7360
7361         if (log_buf && log_buf[0] != '\0') {
7362                 ret = -LIBBPF_ERRNO__VERIFY;
7363                 pr_warn("-- BEGIN DUMP LOG ---\n");
7364                 pr_warn("\n%s\n", log_buf);
7365                 pr_warn("-- END LOG --\n");
7366         } else if (load_attr.insn_cnt >= BPF_MAXINSNS) {
7367                 pr_warn("Program too large (%zu insns), at most %d insns\n",
7368                         load_attr.insn_cnt, BPF_MAXINSNS);
7369                 ret = -LIBBPF_ERRNO__PROG2BIG;
7370         } else if (load_attr.prog_type != BPF_PROG_TYPE_KPROBE) {
7371                 /* Wrong program type? */
7372                 int fd;
7373
7374                 load_attr.prog_type = BPF_PROG_TYPE_KPROBE;
7375                 load_attr.expected_attach_type = 0;
7376                 load_attr.log_buf = NULL;
7377                 load_attr.log_buf_sz = 0;
7378                 fd = libbpf__bpf_prog_load(&load_attr);
7379                 if (fd >= 0) {
7380                         close(fd);
7381                         ret = -LIBBPF_ERRNO__PROGTYPE;
7382                         goto out;
7383                 }
7384         }
7385
7386 out:
7387         free(log_buf);
7388         return ret;
7389 }
7390
7391 static int bpf_program__record_externs(struct bpf_program *prog)
7392 {
7393         struct bpf_object *obj = prog->obj;
7394         int i;
7395
7396         for (i = 0; i < prog->nr_reloc; i++) {
7397                 struct reloc_desc *relo = &prog->reloc_desc[i];
7398                 struct extern_desc *ext = &obj->externs[relo->sym_off];
7399
7400                 switch (relo->type) {
7401                 case RELO_EXTERN_VAR:
7402                         if (ext->type != EXT_KSYM)
7403                                 continue;
7404                         if (!ext->ksym.type_id) {
7405                                 pr_warn("typeless ksym %s is not supported yet\n",
7406                                         ext->name);
7407                                 return -ENOTSUP;
7408                         }
7409                         bpf_gen__record_extern(obj->gen_loader, ext->name, BTF_KIND_VAR,
7410                                                relo->insn_idx);
7411                         break;
7412                 case RELO_EXTERN_FUNC:
7413                         bpf_gen__record_extern(obj->gen_loader, ext->name, BTF_KIND_FUNC,
7414                                                relo->insn_idx);
7415                         break;
7416                 default:
7417                         continue;
7418                 }
7419         }
7420         return 0;
7421 }
7422
7423 static int libbpf_find_attach_btf_id(struct bpf_program *prog, int *btf_obj_fd, int *btf_type_id);
7424
7425 int bpf_program__load(struct bpf_program *prog, char *license, __u32 kern_ver)
7426 {
7427         int err = 0, fd, i;
7428
7429         if (prog->obj->loaded) {
7430                 pr_warn("prog '%s': can't load after object was loaded\n", prog->name);
7431                 return libbpf_err(-EINVAL);
7432         }
7433
7434         if ((prog->type == BPF_PROG_TYPE_TRACING ||
7435              prog->type == BPF_PROG_TYPE_LSM ||
7436              prog->type == BPF_PROG_TYPE_EXT) && !prog->attach_btf_id) {
7437                 int btf_obj_fd = 0, btf_type_id = 0;
7438
7439                 err = libbpf_find_attach_btf_id(prog, &btf_obj_fd, &btf_type_id);
7440                 if (err)
7441                         return libbpf_err(err);
7442
7443                 prog->attach_btf_obj_fd = btf_obj_fd;
7444                 prog->attach_btf_id = btf_type_id;
7445         }
7446
7447         if (prog->instances.nr < 0 || !prog->instances.fds) {
7448                 if (prog->preprocessor) {
7449                         pr_warn("Internal error: can't load program '%s'\n",
7450                                 prog->name);
7451                         return libbpf_err(-LIBBPF_ERRNO__INTERNAL);
7452                 }
7453
7454                 prog->instances.fds = malloc(sizeof(int));
7455                 if (!prog->instances.fds) {
7456                         pr_warn("Not enough memory for BPF fds\n");
7457                         return libbpf_err(-ENOMEM);
7458                 }
7459                 prog->instances.nr = 1;
7460                 prog->instances.fds[0] = -1;
7461         }
7462
7463         if (!prog->preprocessor) {
7464                 if (prog->instances.nr != 1) {
7465                         pr_warn("prog '%s': inconsistent nr(%d) != 1\n",
7466                                 prog->name, prog->instances.nr);
7467                 }
7468                 if (prog->obj->gen_loader)
7469                         bpf_program__record_externs(prog);
7470                 err = load_program(prog, prog->insns, prog->insns_cnt,
7471                                    license, kern_ver, &fd);
7472                 if (!err)
7473                         prog->instances.fds[0] = fd;
7474                 goto out;
7475         }
7476
7477         for (i = 0; i < prog->instances.nr; i++) {
7478                 struct bpf_prog_prep_result result;
7479                 bpf_program_prep_t preprocessor = prog->preprocessor;
7480
7481                 memset(&result, 0, sizeof(result));
7482                 err = preprocessor(prog, i, prog->insns,
7483                                    prog->insns_cnt, &result);
7484                 if (err) {
7485                         pr_warn("Preprocessing the %dth instance of program '%s' failed\n",
7486                                 i, prog->name);
7487                         goto out;
7488                 }
7489
7490                 if (!result.new_insn_ptr || !result.new_insn_cnt) {
7491                         pr_debug("Skip loading the %dth instance of program '%s'\n",
7492                                  i, prog->name);
7493                         prog->instances.fds[i] = -1;
7494                         if (result.pfd)
7495                                 *result.pfd = -1;
7496                         continue;
7497                 }
7498
7499                 err = load_program(prog, result.new_insn_ptr,
7500                                    result.new_insn_cnt, license, kern_ver, &fd);
7501                 if (err) {
7502                         pr_warn("Loading the %dth instance of program '%s' failed\n",
7503                                 i, prog->name);
7504                         goto out;
7505                 }
7506
7507                 if (result.pfd)
7508                         *result.pfd = fd;
7509                 prog->instances.fds[i] = fd;
7510         }
7511 out:
7512         if (err)
7513                 pr_warn("failed to load program '%s'\n", prog->name);
7514         zfree(&prog->insns);
7515         prog->insns_cnt = 0;
7516         return libbpf_err(err);
7517 }
7518
7519 static int
7520 bpf_object__load_progs(struct bpf_object *obj, int log_level)
7521 {
7522         struct bpf_program *prog;
7523         size_t i;
7524         int err;
7525
7526         for (i = 0; i < obj->nr_programs; i++) {
7527                 prog = &obj->programs[i];
7528                 err = bpf_object__sanitize_prog(obj, prog);
7529                 if (err)
7530                         return err;
7531         }
7532
7533         for (i = 0; i < obj->nr_programs; i++) {
7534                 prog = &obj->programs[i];
7535                 if (prog_is_subprog(obj, prog))
7536                         continue;
7537                 if (!prog->load) {
7538                         pr_debug("prog '%s': skipped loading\n", prog->name);
7539                         continue;
7540                 }
7541                 prog->log_level |= log_level;
7542                 err = bpf_program__load(prog, obj->license, obj->kern_version);
7543                 if (err)
7544                         return err;
7545         }
7546         if (obj->gen_loader)
7547                 bpf_object__free_relocs(obj);
7548         return 0;
7549 }
7550
7551 static const struct bpf_sec_def *find_sec_def(const char *sec_name);
7552
7553 static struct bpf_object *
7554 __bpf_object__open(const char *path, const void *obj_buf, size_t obj_buf_sz,
7555                    const struct bpf_object_open_opts *opts)
7556 {
7557         const char *obj_name, *kconfig;
7558         struct bpf_program *prog;
7559         struct bpf_object *obj;
7560         char tmp_name[64];
7561         int err;
7562
7563         if (elf_version(EV_CURRENT) == EV_NONE) {
7564                 pr_warn("failed to init libelf for %s\n",
7565                         path ? : "(mem buf)");
7566                 return ERR_PTR(-LIBBPF_ERRNO__LIBELF);
7567         }
7568
7569         if (!OPTS_VALID(opts, bpf_object_open_opts))
7570                 return ERR_PTR(-EINVAL);
7571
7572         obj_name = OPTS_GET(opts, object_name, NULL);
7573         if (obj_buf) {
7574                 if (!obj_name) {
7575                         snprintf(tmp_name, sizeof(tmp_name), "%lx-%lx",
7576                                  (unsigned long)obj_buf,
7577                                  (unsigned long)obj_buf_sz);
7578                         obj_name = tmp_name;
7579                 }
7580                 path = obj_name;
7581                 pr_debug("loading object '%s' from buffer\n", obj_name);
7582         }
7583
7584         obj = bpf_object__new(path, obj_buf, obj_buf_sz, obj_name);
7585         if (IS_ERR(obj))
7586                 return obj;
7587
7588         kconfig = OPTS_GET(opts, kconfig, NULL);
7589         if (kconfig) {
7590                 obj->kconfig = strdup(kconfig);
7591                 if (!obj->kconfig)
7592                         return ERR_PTR(-ENOMEM);
7593         }
7594
7595         err = bpf_object__elf_init(obj);
7596         err = err ? : bpf_object__check_endianness(obj);
7597         err = err ? : bpf_object__elf_collect(obj);
7598         err = err ? : bpf_object__collect_externs(obj);
7599         err = err ? : bpf_object__finalize_btf(obj);
7600         err = err ? : bpf_object__init_maps(obj, opts);
7601         err = err ? : bpf_object__collect_relos(obj);
7602         if (err)
7603                 goto out;
7604         bpf_object__elf_finish(obj);
7605
7606         bpf_object__for_each_program(prog, obj) {
7607                 prog->sec_def = find_sec_def(prog->sec_name);
7608                 if (!prog->sec_def) {
7609                         /* couldn't guess, but user might manually specify */
7610                         pr_debug("prog '%s': unrecognized ELF section name '%s'\n",
7611                                 prog->name, prog->sec_name);
7612                         continue;
7613                 }
7614
7615                 if (prog->sec_def->is_sleepable)
7616                         prog->prog_flags |= BPF_F_SLEEPABLE;
7617                 bpf_program__set_type(prog, prog->sec_def->prog_type);
7618                 bpf_program__set_expected_attach_type(prog,
7619                                 prog->sec_def->expected_attach_type);
7620
7621                 if (prog->sec_def->prog_type == BPF_PROG_TYPE_TRACING ||
7622                     prog->sec_def->prog_type == BPF_PROG_TYPE_EXT)
7623                         prog->attach_prog_fd = OPTS_GET(opts, attach_prog_fd, 0);
7624         }
7625
7626         return obj;
7627 out:
7628         bpf_object__close(obj);
7629         return ERR_PTR(err);
7630 }
7631
7632 static struct bpf_object *
7633 __bpf_object__open_xattr(struct bpf_object_open_attr *attr, int flags)
7634 {
7635         DECLARE_LIBBPF_OPTS(bpf_object_open_opts, opts,
7636                 .relaxed_maps = flags & MAPS_RELAX_COMPAT,
7637         );
7638
7639         /* param validation */
7640         if (!attr->file)
7641                 return NULL;
7642
7643         pr_debug("loading %s\n", attr->file);
7644         return __bpf_object__open(attr->file, NULL, 0, &opts);
7645 }
7646
7647 struct bpf_object *bpf_object__open_xattr(struct bpf_object_open_attr *attr)
7648 {
7649         return libbpf_ptr(__bpf_object__open_xattr(attr, 0));
7650 }
7651
7652 struct bpf_object *bpf_object__open(const char *path)
7653 {
7654         struct bpf_object_open_attr attr = {
7655                 .file           = path,
7656                 .prog_type      = BPF_PROG_TYPE_UNSPEC,
7657         };
7658
7659         return libbpf_ptr(__bpf_object__open_xattr(&attr, 0));
7660 }
7661
7662 struct bpf_object *
7663 bpf_object__open_file(const char *path, const struct bpf_object_open_opts *opts)
7664 {
7665         if (!path)
7666                 return libbpf_err_ptr(-EINVAL);
7667
7668         pr_debug("loading %s\n", path);
7669
7670         return libbpf_ptr(__bpf_object__open(path, NULL, 0, opts));
7671 }
7672
7673 struct bpf_object *
7674 bpf_object__open_mem(const void *obj_buf, size_t obj_buf_sz,
7675                      const struct bpf_object_open_opts *opts)
7676 {
7677         if (!obj_buf || obj_buf_sz == 0)
7678                 return libbpf_err_ptr(-EINVAL);
7679
7680         return libbpf_ptr(__bpf_object__open(NULL, obj_buf, obj_buf_sz, opts));
7681 }
7682
7683 struct bpf_object *
7684 bpf_object__open_buffer(const void *obj_buf, size_t obj_buf_sz,
7685                         const char *name)
7686 {
7687         DECLARE_LIBBPF_OPTS(bpf_object_open_opts, opts,
7688                 .object_name = name,
7689                 /* wrong default, but backwards-compatible */
7690                 .relaxed_maps = true,
7691         );
7692
7693         /* returning NULL is wrong, but backwards-compatible */
7694         if (!obj_buf || obj_buf_sz == 0)
7695                 return errno = EINVAL, NULL;
7696
7697         return libbpf_ptr(__bpf_object__open(NULL, obj_buf, obj_buf_sz, &opts));
7698 }
7699
7700 int bpf_object__unload(struct bpf_object *obj)
7701 {
7702         size_t i;
7703
7704         if (!obj)
7705                 return libbpf_err(-EINVAL);
7706
7707         for (i = 0; i < obj->nr_maps; i++) {
7708                 zclose(obj->maps[i].fd);
7709                 if (obj->maps[i].st_ops)
7710                         zfree(&obj->maps[i].st_ops->kern_vdata);
7711         }
7712
7713         for (i = 0; i < obj->nr_programs; i++)
7714                 bpf_program__unload(&obj->programs[i]);
7715
7716         return 0;
7717 }
7718
7719 static int bpf_object__sanitize_maps(struct bpf_object *obj)
7720 {
7721         struct bpf_map *m;
7722
7723         bpf_object__for_each_map(m, obj) {
7724                 if (!bpf_map__is_internal(m))
7725                         continue;
7726                 if (!kernel_supports(obj, FEAT_GLOBAL_DATA)) {
7727                         pr_warn("kernel doesn't support global data\n");
7728                         return -ENOTSUP;
7729                 }
7730                 if (!kernel_supports(obj, FEAT_ARRAY_MMAP))
7731                         m->def.map_flags ^= BPF_F_MMAPABLE;
7732         }
7733
7734         return 0;
7735 }
7736
7737 static int bpf_object__read_kallsyms_file(struct bpf_object *obj)
7738 {
7739         char sym_type, sym_name[500];
7740         unsigned long long sym_addr;
7741         const struct btf_type *t;
7742         struct extern_desc *ext;
7743         int ret, err = 0;
7744         FILE *f;
7745
7746         f = fopen("/proc/kallsyms", "r");
7747         if (!f) {
7748                 err = -errno;
7749                 pr_warn("failed to open /proc/kallsyms: %d\n", err);
7750                 return err;
7751         }
7752
7753         while (true) {
7754                 ret = fscanf(f, "%llx %c %499s%*[^\n]\n",
7755                              &sym_addr, &sym_type, sym_name);
7756                 if (ret == EOF && feof(f))
7757                         break;
7758                 if (ret != 3) {
7759                         pr_warn("failed to read kallsyms entry: %d\n", ret);
7760                         err = -EINVAL;
7761                         goto out;
7762                 }
7763
7764                 ext = find_extern_by_name(obj, sym_name);
7765                 if (!ext || ext->type != EXT_KSYM)
7766                         continue;
7767
7768                 t = btf__type_by_id(obj->btf, ext->btf_id);
7769                 if (!btf_is_var(t))
7770                         continue;
7771
7772                 if (ext->is_set && ext->ksym.addr != sym_addr) {
7773                         pr_warn("extern (ksym) '%s' resolution is ambiguous: 0x%llx or 0x%llx\n",
7774                                 sym_name, ext->ksym.addr, sym_addr);
7775                         err = -EINVAL;
7776                         goto out;
7777                 }
7778                 if (!ext->is_set) {
7779                         ext->is_set = true;
7780                         ext->ksym.addr = sym_addr;
7781                         pr_debug("extern (ksym) %s=0x%llx\n", sym_name, sym_addr);
7782                 }
7783         }
7784
7785 out:
7786         fclose(f);
7787         return err;
7788 }
7789
7790 static int find_ksym_btf_id(struct bpf_object *obj, const char *ksym_name,
7791                             __u16 kind, struct btf **res_btf,
7792                             int *res_btf_fd)
7793 {
7794         int i, id, btf_fd, err;
7795         struct btf *btf;
7796
7797         btf = obj->btf_vmlinux;
7798         btf_fd = 0;
7799         id = btf__find_by_name_kind(btf, ksym_name, kind);
7800
7801         if (id == -ENOENT) {
7802                 err = load_module_btfs(obj);
7803                 if (err)
7804                         return err;
7805
7806                 for (i = 0; i < obj->btf_module_cnt; i++) {
7807                         btf = obj->btf_modules[i].btf;
7808                         /* we assume module BTF FD is always >0 */
7809                         btf_fd = obj->btf_modules[i].fd;
7810                         id = btf__find_by_name_kind(btf, ksym_name, kind);
7811                         if (id != -ENOENT)
7812                                 break;
7813                 }
7814         }
7815         if (id <= 0) {
7816                 pr_warn("extern (%s ksym) '%s': failed to find BTF ID in kernel BTF(s).\n",
7817                         __btf_kind_str(kind), ksym_name);
7818                 return -ESRCH;
7819         }
7820
7821         *res_btf = btf;
7822         *res_btf_fd = btf_fd;
7823         return id;
7824 }
7825
7826 static int bpf_object__resolve_ksym_var_btf_id(struct bpf_object *obj,
7827                                                struct extern_desc *ext)
7828 {
7829         const struct btf_type *targ_var, *targ_type;
7830         __u32 targ_type_id, local_type_id;
7831         const char *targ_var_name;
7832         int id, btf_fd = 0, err;
7833         struct btf *btf = NULL;
7834
7835         id = find_ksym_btf_id(obj, ext->name, BTF_KIND_VAR, &btf, &btf_fd);
7836         if (id < 0)
7837                 return id;
7838
7839         /* find local type_id */
7840         local_type_id = ext->ksym.type_id;
7841
7842         /* find target type_id */
7843         targ_var = btf__type_by_id(btf, id);
7844         targ_var_name = btf__name_by_offset(btf, targ_var->name_off);
7845         targ_type = skip_mods_and_typedefs(btf, targ_var->type, &targ_type_id);
7846
7847         err = bpf_core_types_are_compat(obj->btf, local_type_id,
7848                                         btf, targ_type_id);
7849         if (err <= 0) {
7850                 const struct btf_type *local_type;
7851                 const char *targ_name, *local_name;
7852
7853                 local_type = btf__type_by_id(obj->btf, local_type_id);
7854                 local_name = btf__name_by_offset(obj->btf, local_type->name_off);
7855                 targ_name = btf__name_by_offset(btf, targ_type->name_off);
7856
7857                 pr_warn("extern (var ksym) '%s': incompatible types, expected [%d] %s %s, but kernel has [%d] %s %s\n",
7858                         ext->name, local_type_id,
7859                         btf_kind_str(local_type), local_name, targ_type_id,
7860                         btf_kind_str(targ_type), targ_name);
7861                 return -EINVAL;
7862         }
7863
7864         ext->is_set = true;
7865         ext->ksym.kernel_btf_obj_fd = btf_fd;
7866         ext->ksym.kernel_btf_id = id;
7867         pr_debug("extern (var ksym) '%s': resolved to [%d] %s %s\n",
7868                  ext->name, id, btf_kind_str(targ_var), targ_var_name);
7869
7870         return 0;
7871 }
7872
7873 static int bpf_object__resolve_ksym_func_btf_id(struct bpf_object *obj,
7874                                                 struct extern_desc *ext)
7875 {
7876         int local_func_proto_id, kfunc_proto_id, kfunc_id;
7877         const struct btf_type *kern_func;
7878         struct btf *kern_btf = NULL;
7879         int ret, kern_btf_fd = 0;
7880
7881         local_func_proto_id = ext->ksym.type_id;
7882
7883         kfunc_id = find_ksym_btf_id(obj, ext->name, BTF_KIND_FUNC,
7884                                     &kern_btf, &kern_btf_fd);
7885         if (kfunc_id < 0) {
7886                 pr_warn("extern (func ksym) '%s': not found in kernel BTF\n",
7887                         ext->name);
7888                 return kfunc_id;
7889         }
7890
7891         if (kern_btf != obj->btf_vmlinux) {
7892                 pr_warn("extern (func ksym) '%s': function in kernel module is not supported\n",
7893                         ext->name);
7894                 return -ENOTSUP;
7895         }
7896
7897         kern_func = btf__type_by_id(kern_btf, kfunc_id);
7898         kfunc_proto_id = kern_func->type;
7899
7900         ret = bpf_core_types_are_compat(obj->btf, local_func_proto_id,
7901                                         kern_btf, kfunc_proto_id);
7902         if (ret <= 0) {
7903                 pr_warn("extern (func ksym) '%s': func_proto [%d] incompatible with kernel [%d]\n",
7904                         ext->name, local_func_proto_id, kfunc_proto_id);
7905                 return -EINVAL;
7906         }
7907
7908         ext->is_set = true;
7909         ext->ksym.kernel_btf_obj_fd = kern_btf_fd;
7910         ext->ksym.kernel_btf_id = kfunc_id;
7911         pr_debug("extern (func ksym) '%s': resolved to kernel [%d]\n",
7912                  ext->name, kfunc_id);
7913
7914         return 0;
7915 }
7916
7917 static int bpf_object__resolve_ksyms_btf_id(struct bpf_object *obj)
7918 {
7919         const struct btf_type *t;
7920         struct extern_desc *ext;
7921         int i, err;
7922
7923         for (i = 0; i < obj->nr_extern; i++) {
7924                 ext = &obj->externs[i];
7925                 if (ext->type != EXT_KSYM || !ext->ksym.type_id)
7926                         continue;
7927
7928                 if (obj->gen_loader) {
7929                         ext->is_set = true;
7930                         ext->ksym.kernel_btf_obj_fd = 0;
7931                         ext->ksym.kernel_btf_id = 0;
7932                         continue;
7933                 }
7934                 t = btf__type_by_id(obj->btf, ext->btf_id);
7935                 if (btf_is_var(t))
7936                         err = bpf_object__resolve_ksym_var_btf_id(obj, ext);
7937                 else
7938                         err = bpf_object__resolve_ksym_func_btf_id(obj, ext);
7939                 if (err)
7940                         return err;
7941         }
7942         return 0;
7943 }
7944
7945 static int bpf_object__resolve_externs(struct bpf_object *obj,
7946                                        const char *extra_kconfig)
7947 {
7948         bool need_config = false, need_kallsyms = false;
7949         bool need_vmlinux_btf = false;
7950         struct extern_desc *ext;
7951         void *kcfg_data = NULL;
7952         int err, i;
7953
7954         if (obj->nr_extern == 0)
7955                 return 0;
7956
7957         if (obj->kconfig_map_idx >= 0)
7958                 kcfg_data = obj->maps[obj->kconfig_map_idx].mmaped;
7959
7960         for (i = 0; i < obj->nr_extern; i++) {
7961                 ext = &obj->externs[i];
7962
7963                 if (ext->type == EXT_KCFG &&
7964                     strcmp(ext->name, "LINUX_KERNEL_VERSION") == 0) {
7965                         void *ext_val = kcfg_data + ext->kcfg.data_off;
7966                         __u32 kver = get_kernel_version();
7967
7968                         if (!kver) {
7969                                 pr_warn("failed to get kernel version\n");
7970                                 return -EINVAL;
7971                         }
7972                         err = set_kcfg_value_num(ext, ext_val, kver);
7973                         if (err)
7974                                 return err;
7975                         pr_debug("extern (kcfg) %s=0x%x\n", ext->name, kver);
7976                 } else if (ext->type == EXT_KCFG &&
7977                            strncmp(ext->name, "CONFIG_", 7) == 0) {
7978                         need_config = true;
7979                 } else if (ext->type == EXT_KSYM) {
7980                         if (ext->ksym.type_id)
7981                                 need_vmlinux_btf = true;
7982                         else
7983                                 need_kallsyms = true;
7984                 } else {
7985                         pr_warn("unrecognized extern '%s'\n", ext->name);
7986                         return -EINVAL;
7987                 }
7988         }
7989         if (need_config && extra_kconfig) {
7990                 err = bpf_object__read_kconfig_mem(obj, extra_kconfig, kcfg_data);
7991                 if (err)
7992                         return -EINVAL;
7993                 need_config = false;
7994                 for (i = 0; i < obj->nr_extern; i++) {
7995                         ext = &obj->externs[i];
7996                         if (ext->type == EXT_KCFG && !ext->is_set) {
7997                                 need_config = true;
7998                                 break;
7999                         }
8000                 }
8001         }
8002         if (need_config) {
8003                 err = bpf_object__read_kconfig_file(obj, kcfg_data);
8004                 if (err)
8005                         return -EINVAL;
8006         }
8007         if (need_kallsyms) {
8008                 err = bpf_object__read_kallsyms_file(obj);
8009                 if (err)
8010                         return -EINVAL;
8011         }
8012         if (need_vmlinux_btf) {
8013                 err = bpf_object__resolve_ksyms_btf_id(obj);
8014                 if (err)
8015                         return -EINVAL;
8016         }
8017         for (i = 0; i < obj->nr_extern; i++) {
8018                 ext = &obj->externs[i];
8019
8020                 if (!ext->is_set && !ext->is_weak) {
8021                         pr_warn("extern %s (strong) not resolved\n", ext->name);
8022                         return -ESRCH;
8023                 } else if (!ext->is_set) {
8024                         pr_debug("extern %s (weak) not resolved, defaulting to zero\n",
8025                                  ext->name);
8026                 }
8027         }
8028
8029         return 0;
8030 }
8031
8032 int bpf_object__load_xattr(struct bpf_object_load_attr *attr)
8033 {
8034         struct bpf_object *obj;
8035         int err, i;
8036
8037         if (!attr)
8038                 return libbpf_err(-EINVAL);
8039         obj = attr->obj;
8040         if (!obj)
8041                 return libbpf_err(-EINVAL);
8042
8043         if (obj->loaded) {
8044                 pr_warn("object '%s': load can't be attempted twice\n", obj->name);
8045                 return libbpf_err(-EINVAL);
8046         }
8047
8048         if (obj->gen_loader)
8049                 bpf_gen__init(obj->gen_loader, attr->log_level);
8050
8051         err = bpf_object__probe_loading(obj);
8052         err = err ? : bpf_object__load_vmlinux_btf(obj, false);
8053         err = err ? : bpf_object__resolve_externs(obj, obj->kconfig);
8054         err = err ? : bpf_object__sanitize_and_load_btf(obj);
8055         err = err ? : bpf_object__sanitize_maps(obj);
8056         err = err ? : bpf_object__init_kern_struct_ops_maps(obj);
8057         err = err ? : bpf_object__create_maps(obj);
8058         err = err ? : bpf_object__relocate(obj, attr->target_btf_path);
8059         err = err ? : bpf_object__load_progs(obj, attr->log_level);
8060
8061         if (obj->gen_loader) {
8062                 /* reset FDs */
8063                 btf__set_fd(obj->btf, -1);
8064                 for (i = 0; i < obj->nr_maps; i++)
8065                         obj->maps[i].fd = -1;
8066                 if (!err)
8067                         err = bpf_gen__finish(obj->gen_loader);
8068         }
8069
8070         /* clean up module BTFs */
8071         for (i = 0; i < obj->btf_module_cnt; i++) {
8072                 close(obj->btf_modules[i].fd);
8073                 btf__free(obj->btf_modules[i].btf);
8074                 free(obj->btf_modules[i].name);
8075         }
8076         free(obj->btf_modules);
8077
8078         /* clean up vmlinux BTF */
8079         btf__free(obj->btf_vmlinux);
8080         obj->btf_vmlinux = NULL;
8081
8082         obj->loaded = true; /* doesn't matter if successfully or not */
8083
8084         if (err)
8085                 goto out;
8086
8087         return 0;
8088 out:
8089         /* unpin any maps that were auto-pinned during load */
8090         for (i = 0; i < obj->nr_maps; i++)
8091                 if (obj->maps[i].pinned && !obj->maps[i].reused)
8092                         bpf_map__unpin(&obj->maps[i], NULL);
8093
8094         bpf_object__unload(obj);
8095         pr_warn("failed to load object '%s'\n", obj->path);
8096         return libbpf_err(err);
8097 }
8098
8099 int bpf_object__load(struct bpf_object *obj)
8100 {
8101         struct bpf_object_load_attr attr = {
8102                 .obj = obj,
8103         };
8104
8105         return bpf_object__load_xattr(&attr);
8106 }
8107
8108 static int make_parent_dir(const char *path)
8109 {
8110         char *cp, errmsg[STRERR_BUFSIZE];
8111         char *dname, *dir;
8112         int err = 0;
8113
8114         dname = strdup(path);
8115         if (dname == NULL)
8116                 return -ENOMEM;
8117
8118         dir = dirname(dname);
8119         if (mkdir(dir, 0700) && errno != EEXIST)
8120                 err = -errno;
8121
8122         free(dname);
8123         if (err) {
8124                 cp = libbpf_strerror_r(-err, errmsg, sizeof(errmsg));
8125                 pr_warn("failed to mkdir %s: %s\n", path, cp);
8126         }
8127         return err;
8128 }
8129
8130 static int check_path(const char *path)
8131 {
8132         char *cp, errmsg[STRERR_BUFSIZE];
8133         struct statfs st_fs;
8134         char *dname, *dir;
8135         int err = 0;
8136
8137         if (path == NULL)
8138                 return -EINVAL;
8139
8140         dname = strdup(path);
8141         if (dname == NULL)
8142                 return -ENOMEM;
8143
8144         dir = dirname(dname);
8145         if (statfs(dir, &st_fs)) {
8146                 cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg));
8147                 pr_warn("failed to statfs %s: %s\n", dir, cp);
8148                 err = -errno;
8149         }
8150         free(dname);
8151
8152         if (!err && st_fs.f_type != BPF_FS_MAGIC) {
8153                 pr_warn("specified path %s is not on BPF FS\n", path);
8154                 err = -EINVAL;
8155         }
8156
8157         return err;
8158 }
8159
8160 int bpf_program__pin_instance(struct bpf_program *prog, const char *path,
8161                               int instance)
8162 {
8163         char *cp, errmsg[STRERR_BUFSIZE];
8164         int err;
8165
8166         err = make_parent_dir(path);
8167         if (err)
8168                 return libbpf_err(err);
8169
8170         err = check_path(path);
8171         if (err)
8172                 return libbpf_err(err);
8173
8174         if (prog == NULL) {
8175                 pr_warn("invalid program pointer\n");
8176                 return libbpf_err(-EINVAL);
8177         }
8178
8179         if (instance < 0 || instance >= prog->instances.nr) {
8180                 pr_warn("invalid prog instance %d of prog %s (max %d)\n",
8181                         instance, prog->name, prog->instances.nr);
8182                 return libbpf_err(-EINVAL);
8183         }
8184
8185         if (bpf_obj_pin(prog->instances.fds[instance], path)) {
8186                 err = -errno;
8187                 cp = libbpf_strerror_r(err, errmsg, sizeof(errmsg));
8188                 pr_warn("failed to pin program: %s\n", cp);
8189                 return libbpf_err(err);
8190         }
8191         pr_debug("pinned program '%s'\n", path);
8192
8193         return 0;
8194 }
8195
8196 int bpf_program__unpin_instance(struct bpf_program *prog, const char *path,
8197                                 int instance)
8198 {
8199         int err;
8200
8201         err = check_path(path);
8202         if (err)
8203                 return libbpf_err(err);
8204
8205         if (prog == NULL) {
8206                 pr_warn("invalid program pointer\n");
8207                 return libbpf_err(-EINVAL);
8208         }
8209
8210         if (instance < 0 || instance >= prog->instances.nr) {
8211                 pr_warn("invalid prog instance %d of prog %s (max %d)\n",
8212                         instance, prog->name, prog->instances.nr);
8213                 return libbpf_err(-EINVAL);
8214         }
8215
8216         err = unlink(path);
8217         if (err != 0)
8218                 return libbpf_err(-errno);
8219
8220         pr_debug("unpinned program '%s'\n", path);
8221
8222         return 0;
8223 }
8224
8225 int bpf_program__pin(struct bpf_program *prog, const char *path)
8226 {
8227         int i, err;
8228
8229         err = make_parent_dir(path);
8230         if (err)
8231                 return libbpf_err(err);
8232
8233         err = check_path(path);
8234         if (err)
8235                 return libbpf_err(err);
8236
8237         if (prog == NULL) {
8238                 pr_warn("invalid program pointer\n");
8239                 return libbpf_err(-EINVAL);
8240         }
8241
8242         if (prog->instances.nr <= 0) {
8243                 pr_warn("no instances of prog %s to pin\n", prog->name);
8244                 return libbpf_err(-EINVAL);
8245         }
8246
8247         if (prog->instances.nr == 1) {
8248                 /* don't create subdirs when pinning single instance */
8249                 return bpf_program__pin_instance(prog, path, 0);
8250         }
8251
8252         for (i = 0; i < prog->instances.nr; i++) {
8253                 char buf[PATH_MAX];
8254                 int len;
8255
8256                 len = snprintf(buf, PATH_MAX, "%s/%d", path, i);
8257                 if (len < 0) {
8258                         err = -EINVAL;
8259                         goto err_unpin;
8260                 } else if (len >= PATH_MAX) {
8261                         err = -ENAMETOOLONG;
8262                         goto err_unpin;
8263                 }
8264
8265                 err = bpf_program__pin_instance(prog, buf, i);
8266                 if (err)
8267                         goto err_unpin;
8268         }
8269
8270         return 0;
8271
8272 err_unpin:
8273         for (i = i - 1; i >= 0; i--) {
8274                 char buf[PATH_MAX];
8275                 int len;
8276
8277                 len = snprintf(buf, PATH_MAX, "%s/%d", path, i);
8278                 if (len < 0)
8279                         continue;
8280                 else if (len >= PATH_MAX)
8281                         continue;
8282
8283                 bpf_program__unpin_instance(prog, buf, i);
8284         }
8285
8286         rmdir(path);
8287
8288         return libbpf_err(err);
8289 }
8290
8291 int bpf_program__unpin(struct bpf_program *prog, const char *path)
8292 {
8293         int i, err;
8294
8295         err = check_path(path);
8296         if (err)
8297                 return libbpf_err(err);
8298
8299         if (prog == NULL) {
8300                 pr_warn("invalid program pointer\n");
8301                 return libbpf_err(-EINVAL);
8302         }
8303
8304         if (prog->instances.nr <= 0) {
8305                 pr_warn("no instances of prog %s to pin\n", prog->name);
8306                 return libbpf_err(-EINVAL);
8307         }
8308
8309         if (prog->instances.nr == 1) {
8310                 /* don't create subdirs when pinning single instance */
8311                 return bpf_program__unpin_instance(prog, path, 0);
8312         }
8313
8314         for (i = 0; i < prog->instances.nr; i++) {
8315                 char buf[PATH_MAX];
8316                 int len;
8317
8318                 len = snprintf(buf, PATH_MAX, "%s/%d", path, i);
8319                 if (len < 0)
8320                         return libbpf_err(-EINVAL);
8321                 else if (len >= PATH_MAX)
8322                         return libbpf_err(-ENAMETOOLONG);
8323
8324                 err = bpf_program__unpin_instance(prog, buf, i);
8325                 if (err)
8326                         return err;
8327         }
8328
8329         err = rmdir(path);
8330         if (err)
8331                 return libbpf_err(-errno);
8332
8333         return 0;
8334 }
8335
8336 int bpf_map__pin(struct bpf_map *map, const char *path)
8337 {
8338         char *cp, errmsg[STRERR_BUFSIZE];
8339         int err;
8340
8341         if (map == NULL) {
8342                 pr_warn("invalid map pointer\n");
8343                 return libbpf_err(-EINVAL);
8344         }
8345
8346         if (map->pin_path) {
8347                 if (path && strcmp(path, map->pin_path)) {
8348                         pr_warn("map '%s' already has pin path '%s' different from '%s'\n",
8349                                 bpf_map__name(map), map->pin_path, path);
8350                         return libbpf_err(-EINVAL);
8351                 } else if (map->pinned) {
8352                         pr_debug("map '%s' already pinned at '%s'; not re-pinning\n",
8353                                  bpf_map__name(map), map->pin_path);
8354                         return 0;
8355                 }
8356         } else {
8357                 if (!path) {
8358                         pr_warn("missing a path to pin map '%s' at\n",
8359                                 bpf_map__name(map));
8360                         return libbpf_err(-EINVAL);
8361                 } else if (map->pinned) {
8362                         pr_warn("map '%s' already pinned\n", bpf_map__name(map));
8363                         return libbpf_err(-EEXIST);
8364                 }
8365
8366                 map->pin_path = strdup(path);
8367                 if (!map->pin_path) {
8368                         err = -errno;
8369                         goto out_err;
8370                 }
8371         }
8372
8373         err = make_parent_dir(map->pin_path);
8374         if (err)
8375                 return libbpf_err(err);
8376
8377         err = check_path(map->pin_path);
8378         if (err)
8379                 return libbpf_err(err);
8380
8381         if (bpf_obj_pin(map->fd, map->pin_path)) {
8382                 err = -errno;
8383                 goto out_err;
8384         }
8385
8386         map->pinned = true;
8387         pr_debug("pinned map '%s'\n", map->pin_path);
8388
8389         return 0;
8390
8391 out_err:
8392         cp = libbpf_strerror_r(-err, errmsg, sizeof(errmsg));
8393         pr_warn("failed to pin map: %s\n", cp);
8394         return libbpf_err(err);
8395 }
8396
8397 int bpf_map__unpin(struct bpf_map *map, const char *path)
8398 {
8399         int err;
8400
8401         if (map == NULL) {
8402                 pr_warn("invalid map pointer\n");
8403                 return libbpf_err(-EINVAL);
8404         }
8405
8406         if (map->pin_path) {
8407                 if (path && strcmp(path, map->pin_path)) {
8408                         pr_warn("map '%s' already has pin path '%s' different from '%s'\n",
8409                                 bpf_map__name(map), map->pin_path, path);
8410                         return libbpf_err(-EINVAL);
8411                 }
8412                 path = map->pin_path;
8413         } else if (!path) {
8414                 pr_warn("no path to unpin map '%s' from\n",
8415                         bpf_map__name(map));
8416                 return libbpf_err(-EINVAL);
8417         }
8418
8419         err = check_path(path);
8420         if (err)
8421                 return libbpf_err(err);
8422
8423         err = unlink(path);
8424         if (err != 0)
8425                 return libbpf_err(-errno);
8426
8427         map->pinned = false;
8428         pr_debug("unpinned map '%s' from '%s'\n", bpf_map__name(map), path);
8429
8430         return 0;
8431 }
8432
8433 int bpf_map__set_pin_path(struct bpf_map *map, const char *path)
8434 {
8435         char *new = NULL;
8436
8437         if (path) {
8438                 new = strdup(path);
8439                 if (!new)
8440                         return libbpf_err(-errno);
8441         }
8442
8443         free(map->pin_path);
8444         map->pin_path = new;
8445         return 0;
8446 }
8447
8448 const char *bpf_map__get_pin_path(const struct bpf_map *map)
8449 {
8450         return map->pin_path;
8451 }
8452
8453 bool bpf_map__is_pinned(const struct bpf_map *map)
8454 {
8455         return map->pinned;
8456 }
8457
8458 static void sanitize_pin_path(char *s)
8459 {
8460         /* bpffs disallows periods in path names */
8461         while (*s) {
8462                 if (*s == '.')
8463                         *s = '_';
8464                 s++;
8465         }
8466 }
8467
8468 int bpf_object__pin_maps(struct bpf_object *obj, const char *path)
8469 {
8470         struct bpf_map *map;
8471         int err;
8472
8473         if (!obj)
8474                 return libbpf_err(-ENOENT);
8475
8476         if (!obj->loaded) {
8477                 pr_warn("object not yet loaded; load it first\n");
8478                 return libbpf_err(-ENOENT);
8479         }
8480
8481         bpf_object__for_each_map(map, obj) {
8482                 char *pin_path = NULL;
8483                 char buf[PATH_MAX];
8484
8485                 if (path) {
8486                         int len;
8487
8488                         len = snprintf(buf, PATH_MAX, "%s/%s", path,
8489                                        bpf_map__name(map));
8490                         if (len < 0) {
8491                                 err = -EINVAL;
8492                                 goto err_unpin_maps;
8493                         } else if (len >= PATH_MAX) {
8494                                 err = -ENAMETOOLONG;
8495                                 goto err_unpin_maps;
8496                         }
8497                         sanitize_pin_path(buf);
8498                         pin_path = buf;
8499                 } else if (!map->pin_path) {
8500                         continue;
8501                 }
8502
8503                 err = bpf_map__pin(map, pin_path);
8504                 if (err)
8505                         goto err_unpin_maps;
8506         }
8507
8508         return 0;
8509
8510 err_unpin_maps:
8511         while ((map = bpf_map__prev(map, obj))) {
8512                 if (!map->pin_path)
8513                         continue;
8514
8515                 bpf_map__unpin(map, NULL);
8516         }
8517
8518         return libbpf_err(err);
8519 }
8520
8521 int bpf_object__unpin_maps(struct bpf_object *obj, const char *path)
8522 {
8523         struct bpf_map *map;
8524         int err;
8525
8526         if (!obj)
8527                 return libbpf_err(-ENOENT);
8528
8529         bpf_object__for_each_map(map, obj) {
8530                 char *pin_path = NULL;
8531                 char buf[PATH_MAX];
8532
8533                 if (path) {
8534                         int len;
8535
8536                         len = snprintf(buf, PATH_MAX, "%s/%s", path,
8537                                        bpf_map__name(map));
8538                         if (len < 0)
8539                                 return libbpf_err(-EINVAL);
8540                         else if (len >= PATH_MAX)
8541                                 return libbpf_err(-ENAMETOOLONG);
8542                         sanitize_pin_path(buf);
8543                         pin_path = buf;
8544                 } else if (!map->pin_path) {
8545                         continue;
8546                 }
8547
8548                 err = bpf_map__unpin(map, pin_path);
8549                 if (err)
8550                         return libbpf_err(err);
8551         }
8552
8553         return 0;
8554 }
8555
8556 int bpf_object__pin_programs(struct bpf_object *obj, const char *path)
8557 {
8558         struct bpf_program *prog;
8559         int err;
8560
8561         if (!obj)
8562                 return libbpf_err(-ENOENT);
8563
8564         if (!obj->loaded) {
8565                 pr_warn("object not yet loaded; load it first\n");
8566                 return libbpf_err(-ENOENT);
8567         }
8568
8569         bpf_object__for_each_program(prog, obj) {
8570                 char buf[PATH_MAX];
8571                 int len;
8572
8573                 len = snprintf(buf, PATH_MAX, "%s/%s", path,
8574                                prog->pin_name);
8575                 if (len < 0) {
8576                         err = -EINVAL;
8577                         goto err_unpin_programs;
8578                 } else if (len >= PATH_MAX) {
8579                         err = -ENAMETOOLONG;
8580                         goto err_unpin_programs;
8581                 }
8582
8583                 err = bpf_program__pin(prog, buf);
8584                 if (err)
8585                         goto err_unpin_programs;
8586         }
8587
8588         return 0;
8589
8590 err_unpin_programs:
8591         while ((prog = bpf_program__prev(prog, obj))) {
8592                 char buf[PATH_MAX];
8593                 int len;
8594
8595                 len = snprintf(buf, PATH_MAX, "%s/%s", path,
8596                                prog->pin_name);
8597                 if (len < 0)
8598                         continue;
8599                 else if (len >= PATH_MAX)
8600                         continue;
8601
8602                 bpf_program__unpin(prog, buf);
8603         }
8604
8605         return libbpf_err(err);
8606 }
8607
8608 int bpf_object__unpin_programs(struct bpf_object *obj, const char *path)
8609 {
8610         struct bpf_program *prog;
8611         int err;
8612
8613         if (!obj)
8614                 return libbpf_err(-ENOENT);
8615
8616         bpf_object__for_each_program(prog, obj) {
8617                 char buf[PATH_MAX];
8618                 int len;
8619
8620                 len = snprintf(buf, PATH_MAX, "%s/%s", path,
8621                                prog->pin_name);
8622                 if (len < 0)
8623                         return libbpf_err(-EINVAL);
8624                 else if (len >= PATH_MAX)
8625                         return libbpf_err(-ENAMETOOLONG);
8626
8627                 err = bpf_program__unpin(prog, buf);
8628                 if (err)
8629                         return libbpf_err(err);
8630         }
8631
8632         return 0;
8633 }
8634
8635 int bpf_object__pin(struct bpf_object *obj, const char *path)
8636 {
8637         int err;
8638
8639         err = bpf_object__pin_maps(obj, path);
8640         if (err)
8641                 return libbpf_err(err);
8642
8643         err = bpf_object__pin_programs(obj, path);
8644         if (err) {
8645                 bpf_object__unpin_maps(obj, path);
8646                 return libbpf_err(err);
8647         }
8648
8649         return 0;
8650 }
8651
8652 static void bpf_map__destroy(struct bpf_map *map)
8653 {
8654         if (map->clear_priv)
8655                 map->clear_priv(map, map->priv);
8656         map->priv = NULL;
8657         map->clear_priv = NULL;
8658
8659         if (map->inner_map) {
8660                 bpf_map__destroy(map->inner_map);
8661                 zfree(&map->inner_map);
8662         }
8663
8664         zfree(&map->init_slots);
8665         map->init_slots_sz = 0;
8666
8667         if (map->mmaped) {
8668                 munmap(map->mmaped, bpf_map_mmap_sz(map));
8669                 map->mmaped = NULL;
8670         }
8671
8672         if (map->st_ops) {
8673                 zfree(&map->st_ops->data);
8674                 zfree(&map->st_ops->progs);
8675                 zfree(&map->st_ops->kern_func_off);
8676                 zfree(&map->st_ops);
8677         }
8678
8679         zfree(&map->name);
8680         zfree(&map->pin_path);
8681
8682         if (map->fd >= 0)
8683                 zclose(map->fd);
8684 }
8685
8686 void bpf_object__close(struct bpf_object *obj)
8687 {
8688         size_t i;
8689
8690         if (IS_ERR_OR_NULL(obj))
8691                 return;
8692
8693         if (obj->clear_priv)
8694                 obj->clear_priv(obj, obj->priv);
8695
8696         bpf_gen__free(obj->gen_loader);
8697         bpf_object__elf_finish(obj);
8698         bpf_object__unload(obj);
8699         btf__free(obj->btf);
8700         btf_ext__free(obj->btf_ext);
8701
8702         for (i = 0; i < obj->nr_maps; i++)
8703                 bpf_map__destroy(&obj->maps[i]);
8704
8705         zfree(&obj->kconfig);
8706         zfree(&obj->externs);
8707         obj->nr_extern = 0;
8708
8709         zfree(&obj->maps);
8710         obj->nr_maps = 0;
8711
8712         if (obj->programs && obj->nr_programs) {
8713                 for (i = 0; i < obj->nr_programs; i++)
8714                         bpf_program__exit(&obj->programs[i]);
8715         }
8716         zfree(&obj->programs);
8717
8718         list_del(&obj->list);
8719         free(obj);
8720 }
8721
8722 struct bpf_object *
8723 bpf_object__next(struct bpf_object *prev)
8724 {
8725         struct bpf_object *next;
8726
8727         if (!prev)
8728                 next = list_first_entry(&bpf_objects_list,
8729                                         struct bpf_object,
8730                                         list);
8731         else
8732                 next = list_next_entry(prev, list);
8733
8734         /* Empty list is noticed here so don't need checking on entry. */
8735         if (&next->list == &bpf_objects_list)
8736                 return NULL;
8737
8738         return next;
8739 }
8740
8741 const char *bpf_object__name(const struct bpf_object *obj)
8742 {
8743         return obj ? obj->name : libbpf_err_ptr(-EINVAL);
8744 }
8745
8746 unsigned int bpf_object__kversion(const struct bpf_object *obj)
8747 {
8748         return obj ? obj->kern_version : 0;
8749 }
8750
8751 struct btf *bpf_object__btf(const struct bpf_object *obj)
8752 {
8753         return obj ? obj->btf : NULL;
8754 }
8755
8756 int bpf_object__btf_fd(const struct bpf_object *obj)
8757 {
8758         return obj->btf ? btf__fd(obj->btf) : -1;
8759 }
8760
8761 int bpf_object__set_kversion(struct bpf_object *obj, __u32 kern_version)
8762 {
8763         if (obj->loaded)
8764                 return libbpf_err(-EINVAL);
8765
8766         obj->kern_version = kern_version;
8767
8768         return 0;
8769 }
8770
8771 int bpf_object__set_priv(struct bpf_object *obj, void *priv,
8772                          bpf_object_clear_priv_t clear_priv)
8773 {
8774         if (obj->priv && obj->clear_priv)
8775                 obj->clear_priv(obj, obj->priv);
8776
8777         obj->priv = priv;
8778         obj->clear_priv = clear_priv;
8779         return 0;
8780 }
8781
8782 void *bpf_object__priv(const struct bpf_object *obj)
8783 {
8784         return obj ? obj->priv : libbpf_err_ptr(-EINVAL);
8785 }
8786
8787 int bpf_object__gen_loader(struct bpf_object *obj, struct gen_loader_opts *opts)
8788 {
8789         struct bpf_gen *gen;
8790
8791         if (!opts)
8792                 return -EFAULT;
8793         if (!OPTS_VALID(opts, gen_loader_opts))
8794                 return -EINVAL;
8795         gen = calloc(sizeof(*gen), 1);
8796         if (!gen)
8797                 return -ENOMEM;
8798         gen->opts = opts;
8799         obj->gen_loader = gen;
8800         return 0;
8801 }
8802
8803 static struct bpf_program *
8804 __bpf_program__iter(const struct bpf_program *p, const struct bpf_object *obj,
8805                     bool forward)
8806 {
8807         size_t nr_programs = obj->nr_programs;
8808         ssize_t idx;
8809
8810         if (!nr_programs)
8811                 return NULL;
8812
8813         if (!p)
8814                 /* Iter from the beginning */
8815                 return forward ? &obj->programs[0] :
8816                         &obj->programs[nr_programs - 1];
8817
8818         if (p->obj != obj) {
8819                 pr_warn("error: program handler doesn't match object\n");
8820                 return errno = EINVAL, NULL;
8821         }
8822
8823         idx = (p - obj->programs) + (forward ? 1 : -1);
8824         if (idx >= obj->nr_programs || idx < 0)
8825                 return NULL;
8826         return &obj->programs[idx];
8827 }
8828
8829 struct bpf_program *
8830 bpf_program__next(struct bpf_program *prev, const struct bpf_object *obj)
8831 {
8832         struct bpf_program *prog = prev;
8833
8834         do {
8835                 prog = __bpf_program__iter(prog, obj, true);
8836         } while (prog && prog_is_subprog(obj, prog));
8837
8838         return prog;
8839 }
8840
8841 struct bpf_program *
8842 bpf_program__prev(struct bpf_program *next, const struct bpf_object *obj)
8843 {
8844         struct bpf_program *prog = next;
8845
8846         do {
8847                 prog = __bpf_program__iter(prog, obj, false);
8848         } while (prog && prog_is_subprog(obj, prog));
8849
8850         return prog;
8851 }
8852
8853 int bpf_program__set_priv(struct bpf_program *prog, void *priv,
8854                           bpf_program_clear_priv_t clear_priv)
8855 {
8856         if (prog->priv && prog->clear_priv)
8857                 prog->clear_priv(prog, prog->priv);
8858
8859         prog->priv = priv;
8860         prog->clear_priv = clear_priv;
8861         return 0;
8862 }
8863
8864 void *bpf_program__priv(const struct bpf_program *prog)
8865 {
8866         return prog ? prog->priv : libbpf_err_ptr(-EINVAL);
8867 }
8868
8869 void bpf_program__set_ifindex(struct bpf_program *prog, __u32 ifindex)
8870 {
8871         prog->prog_ifindex = ifindex;
8872 }
8873
8874 const char *bpf_program__name(const struct bpf_program *prog)
8875 {
8876         return prog->name;
8877 }
8878
8879 const char *bpf_program__section_name(const struct bpf_program *prog)
8880 {
8881         return prog->sec_name;
8882 }
8883
8884 const char *bpf_program__title(const struct bpf_program *prog, bool needs_copy)
8885 {
8886         const char *title;
8887
8888         title = prog->sec_name;
8889         if (needs_copy) {
8890                 title = strdup(title);
8891                 if (!title) {
8892                         pr_warn("failed to strdup program title\n");
8893                         return libbpf_err_ptr(-ENOMEM);
8894                 }
8895         }
8896
8897         return title;
8898 }
8899
8900 bool bpf_program__autoload(const struct bpf_program *prog)
8901 {
8902         return prog->load;
8903 }
8904
8905 int bpf_program__set_autoload(struct bpf_program *prog, bool autoload)
8906 {
8907         if (prog->obj->loaded)
8908                 return libbpf_err(-EINVAL);
8909
8910         prog->load = autoload;
8911         return 0;
8912 }
8913
8914 int bpf_program__fd(const struct bpf_program *prog)
8915 {
8916         return bpf_program__nth_fd(prog, 0);
8917 }
8918
8919 size_t bpf_program__size(const struct bpf_program *prog)
8920 {
8921         return prog->insns_cnt * BPF_INSN_SZ;
8922 }
8923
8924 int bpf_program__set_prep(struct bpf_program *prog, int nr_instances,
8925                           bpf_program_prep_t prep)
8926 {
8927         int *instances_fds;
8928
8929         if (nr_instances <= 0 || !prep)
8930                 return libbpf_err(-EINVAL);
8931
8932         if (prog->instances.nr > 0 || prog->instances.fds) {
8933                 pr_warn("Can't set pre-processor after loading\n");
8934                 return libbpf_err(-EINVAL);
8935         }
8936
8937         instances_fds = malloc(sizeof(int) * nr_instances);
8938         if (!instances_fds) {
8939                 pr_warn("alloc memory failed for fds\n");
8940                 return libbpf_err(-ENOMEM);
8941         }
8942
8943         /* fill all fd with -1 */
8944         memset(instances_fds, -1, sizeof(int) * nr_instances);
8945
8946         prog->instances.nr = nr_instances;
8947         prog->instances.fds = instances_fds;
8948         prog->preprocessor = prep;
8949         return 0;
8950 }
8951
8952 int bpf_program__nth_fd(const struct bpf_program *prog, int n)
8953 {
8954         int fd;
8955
8956         if (!prog)
8957                 return libbpf_err(-EINVAL);
8958
8959         if (n >= prog->instances.nr || n < 0) {
8960                 pr_warn("Can't get the %dth fd from program %s: only %d instances\n",
8961                         n, prog->name, prog->instances.nr);
8962                 return libbpf_err(-EINVAL);
8963         }
8964
8965         fd = prog->instances.fds[n];
8966         if (fd < 0) {
8967                 pr_warn("%dth instance of program '%s' is invalid\n",
8968                         n, prog->name);
8969                 return libbpf_err(-ENOENT);
8970         }
8971
8972         return fd;
8973 }
8974
8975 enum bpf_prog_type bpf_program__get_type(const struct bpf_program *prog)
8976 {
8977         return prog->type;
8978 }
8979
8980 void bpf_program__set_type(struct bpf_program *prog, enum bpf_prog_type type)
8981 {
8982         prog->type = type;
8983 }
8984
8985 static bool bpf_program__is_type(const struct bpf_program *prog,
8986                                  enum bpf_prog_type type)
8987 {
8988         return prog ? (prog->type == type) : false;
8989 }
8990
8991 #define BPF_PROG_TYPE_FNS(NAME, TYPE)                           \
8992 int bpf_program__set_##NAME(struct bpf_program *prog)           \
8993 {                                                               \
8994         if (!prog)                                              \
8995                 return libbpf_err(-EINVAL);                     \
8996         bpf_program__set_type(prog, TYPE);                      \
8997         return 0;                                               \
8998 }                                                               \
8999                                                                 \
9000 bool bpf_program__is_##NAME(const struct bpf_program *prog)     \
9001 {                                                               \
9002         return bpf_program__is_type(prog, TYPE);                \
9003 }                                                               \
9004
9005 BPF_PROG_TYPE_FNS(socket_filter, BPF_PROG_TYPE_SOCKET_FILTER);
9006 BPF_PROG_TYPE_FNS(lsm, BPF_PROG_TYPE_LSM);
9007 BPF_PROG_TYPE_FNS(kprobe, BPF_PROG_TYPE_KPROBE);
9008 BPF_PROG_TYPE_FNS(sched_cls, BPF_PROG_TYPE_SCHED_CLS);
9009 BPF_PROG_TYPE_FNS(sched_act, BPF_PROG_TYPE_SCHED_ACT);
9010 BPF_PROG_TYPE_FNS(tracepoint, BPF_PROG_TYPE_TRACEPOINT);
9011 BPF_PROG_TYPE_FNS(raw_tracepoint, BPF_PROG_TYPE_RAW_TRACEPOINT);
9012 BPF_PROG_TYPE_FNS(xdp, BPF_PROG_TYPE_XDP);
9013 BPF_PROG_TYPE_FNS(perf_event, BPF_PROG_TYPE_PERF_EVENT);
9014 BPF_PROG_TYPE_FNS(tracing, BPF_PROG_TYPE_TRACING);
9015 BPF_PROG_TYPE_FNS(struct_ops, BPF_PROG_TYPE_STRUCT_OPS);
9016 BPF_PROG_TYPE_FNS(extension, BPF_PROG_TYPE_EXT);
9017 BPF_PROG_TYPE_FNS(sk_lookup, BPF_PROG_TYPE_SK_LOOKUP);
9018
9019 enum bpf_attach_type
9020 bpf_program__get_expected_attach_type(const struct bpf_program *prog)
9021 {
9022         return prog->expected_attach_type;
9023 }
9024
9025 void bpf_program__set_expected_attach_type(struct bpf_program *prog,
9026                                            enum bpf_attach_type type)
9027 {
9028         prog->expected_attach_type = type;
9029 }
9030
9031 #define BPF_PROG_SEC_IMPL(string, ptype, eatype, eatype_optional,           \
9032                           attachable, attach_btf)                           \
9033         {                                                                   \
9034                 .sec = string,                                              \
9035                 .len = sizeof(string) - 1,                                  \
9036                 .prog_type = ptype,                                         \
9037                 .expected_attach_type = eatype,                             \
9038                 .is_exp_attach_type_optional = eatype_optional,             \
9039                 .is_attachable = attachable,                                \
9040                 .is_attach_btf = attach_btf,                                \
9041         }
9042
9043 /* Programs that can NOT be attached. */
9044 #define BPF_PROG_SEC(string, ptype) BPF_PROG_SEC_IMPL(string, ptype, 0, 0, 0, 0)
9045
9046 /* Programs that can be attached. */
9047 #define BPF_APROG_SEC(string, ptype, atype) \
9048         BPF_PROG_SEC_IMPL(string, ptype, atype, true, 1, 0)
9049
9050 /* Programs that must specify expected attach type at load time. */
9051 #define BPF_EAPROG_SEC(string, ptype, eatype) \
9052         BPF_PROG_SEC_IMPL(string, ptype, eatype, false, 1, 0)
9053
9054 /* Programs that use BTF to identify attach point */
9055 #define BPF_PROG_BTF(string, ptype, eatype) \
9056         BPF_PROG_SEC_IMPL(string, ptype, eatype, false, 0, 1)
9057
9058 /* Programs that can be attached but attach type can't be identified by section
9059  * name. Kept for backward compatibility.
9060  */
9061 #define BPF_APROG_COMPAT(string, ptype) BPF_PROG_SEC(string, ptype)
9062
9063 #define SEC_DEF(sec_pfx, ptype, ...) {                                      \
9064         .sec = sec_pfx,                                                     \
9065         .len = sizeof(sec_pfx) - 1,                                         \
9066         .prog_type = BPF_PROG_TYPE_##ptype,                                 \
9067         __VA_ARGS__                                                         \
9068 }
9069
9070 static struct bpf_link *attach_kprobe(const struct bpf_sec_def *sec,
9071                                       struct bpf_program *prog);
9072 static struct bpf_link *attach_tp(const struct bpf_sec_def *sec,
9073                                   struct bpf_program *prog);
9074 static struct bpf_link *attach_raw_tp(const struct bpf_sec_def *sec,
9075                                       struct bpf_program *prog);
9076 static struct bpf_link *attach_trace(const struct bpf_sec_def *sec,
9077                                      struct bpf_program *prog);
9078 static struct bpf_link *attach_lsm(const struct bpf_sec_def *sec,
9079                                    struct bpf_program *prog);
9080 static struct bpf_link *attach_iter(const struct bpf_sec_def *sec,
9081                                     struct bpf_program *prog);
9082
9083 static const struct bpf_sec_def section_defs[] = {
9084         BPF_PROG_SEC("socket",                  BPF_PROG_TYPE_SOCKET_FILTER),
9085         BPF_EAPROG_SEC("sk_reuseport/migrate",  BPF_PROG_TYPE_SK_REUSEPORT,
9086                                                 BPF_SK_REUSEPORT_SELECT_OR_MIGRATE),
9087         BPF_EAPROG_SEC("sk_reuseport",          BPF_PROG_TYPE_SK_REUSEPORT,
9088                                                 BPF_SK_REUSEPORT_SELECT),
9089         SEC_DEF("kprobe/", KPROBE,
9090                 .attach_fn = attach_kprobe),
9091         BPF_PROG_SEC("uprobe/",                 BPF_PROG_TYPE_KPROBE),
9092         SEC_DEF("kretprobe/", KPROBE,
9093                 .attach_fn = attach_kprobe),
9094         BPF_PROG_SEC("uretprobe/",              BPF_PROG_TYPE_KPROBE),
9095         BPF_PROG_SEC("classifier",              BPF_PROG_TYPE_SCHED_CLS),
9096         BPF_PROG_SEC("action",                  BPF_PROG_TYPE_SCHED_ACT),
9097         SEC_DEF("tracepoint/", TRACEPOINT,
9098                 .attach_fn = attach_tp),
9099         SEC_DEF("tp/", TRACEPOINT,
9100                 .attach_fn = attach_tp),
9101         SEC_DEF("raw_tracepoint/", RAW_TRACEPOINT,
9102                 .attach_fn = attach_raw_tp),
9103         SEC_DEF("raw_tp/", RAW_TRACEPOINT,
9104                 .attach_fn = attach_raw_tp),
9105         SEC_DEF("tp_btf/", TRACING,
9106                 .expected_attach_type = BPF_TRACE_RAW_TP,
9107                 .is_attach_btf = true,
9108                 .attach_fn = attach_trace),
9109         SEC_DEF("fentry/", TRACING,
9110                 .expected_attach_type = BPF_TRACE_FENTRY,
9111                 .is_attach_btf = true,
9112                 .attach_fn = attach_trace),
9113         SEC_DEF("fmod_ret/", TRACING,
9114                 .expected_attach_type = BPF_MODIFY_RETURN,
9115                 .is_attach_btf = true,
9116                 .attach_fn = attach_trace),
9117         SEC_DEF("fexit/", TRACING,
9118                 .expected_attach_type = BPF_TRACE_FEXIT,
9119                 .is_attach_btf = true,
9120                 .attach_fn = attach_trace),
9121         SEC_DEF("fentry.s/", TRACING,
9122                 .expected_attach_type = BPF_TRACE_FENTRY,
9123                 .is_attach_btf = true,
9124                 .is_sleepable = true,
9125                 .attach_fn = attach_trace),
9126         SEC_DEF("fmod_ret.s/", TRACING,
9127                 .expected_attach_type = BPF_MODIFY_RETURN,
9128                 .is_attach_btf = true,
9129                 .is_sleepable = true,
9130                 .attach_fn = attach_trace),
9131         SEC_DEF("fexit.s/", TRACING,
9132                 .expected_attach_type = BPF_TRACE_FEXIT,
9133                 .is_attach_btf = true,
9134                 .is_sleepable = true,
9135                 .attach_fn = attach_trace),
9136         SEC_DEF("freplace/", EXT,
9137                 .is_attach_btf = true,
9138                 .attach_fn = attach_trace),
9139         SEC_DEF("lsm/", LSM,
9140                 .is_attach_btf = true,
9141                 .expected_attach_type = BPF_LSM_MAC,
9142                 .attach_fn = attach_lsm),
9143         SEC_DEF("lsm.s/", LSM,
9144                 .is_attach_btf = true,
9145                 .is_sleepable = true,
9146                 .expected_attach_type = BPF_LSM_MAC,
9147                 .attach_fn = attach_lsm),
9148         SEC_DEF("iter/", TRACING,
9149                 .expected_attach_type = BPF_TRACE_ITER,
9150                 .is_attach_btf = true,
9151                 .attach_fn = attach_iter),
9152         SEC_DEF("syscall", SYSCALL,
9153                 .is_sleepable = true),
9154         BPF_EAPROG_SEC("xdp_devmap/",           BPF_PROG_TYPE_XDP,
9155                                                 BPF_XDP_DEVMAP),
9156         BPF_EAPROG_SEC("xdp_cpumap/",           BPF_PROG_TYPE_XDP,
9157                                                 BPF_XDP_CPUMAP),
9158         BPF_APROG_SEC("xdp",                    BPF_PROG_TYPE_XDP,
9159                                                 BPF_XDP),
9160         BPF_PROG_SEC("perf_event",              BPF_PROG_TYPE_PERF_EVENT),
9161         BPF_PROG_SEC("lwt_in",                  BPF_PROG_TYPE_LWT_IN),
9162         BPF_PROG_SEC("lwt_out",                 BPF_PROG_TYPE_LWT_OUT),
9163         BPF_PROG_SEC("lwt_xmit",                BPF_PROG_TYPE_LWT_XMIT),
9164         BPF_PROG_SEC("lwt_seg6local",           BPF_PROG_TYPE_LWT_SEG6LOCAL),
9165         BPF_APROG_SEC("cgroup_skb/ingress",     BPF_PROG_TYPE_CGROUP_SKB,
9166                                                 BPF_CGROUP_INET_INGRESS),
9167         BPF_APROG_SEC("cgroup_skb/egress",      BPF_PROG_TYPE_CGROUP_SKB,
9168                                                 BPF_CGROUP_INET_EGRESS),
9169         BPF_APROG_COMPAT("cgroup/skb",          BPF_PROG_TYPE_CGROUP_SKB),
9170         BPF_EAPROG_SEC("cgroup/sock_create",    BPF_PROG_TYPE_CGROUP_SOCK,
9171                                                 BPF_CGROUP_INET_SOCK_CREATE),
9172         BPF_EAPROG_SEC("cgroup/sock_release",   BPF_PROG_TYPE_CGROUP_SOCK,
9173                                                 BPF_CGROUP_INET_SOCK_RELEASE),
9174         BPF_APROG_SEC("cgroup/sock",            BPF_PROG_TYPE_CGROUP_SOCK,
9175                                                 BPF_CGROUP_INET_SOCK_CREATE),
9176         BPF_EAPROG_SEC("cgroup/post_bind4",     BPF_PROG_TYPE_CGROUP_SOCK,
9177                                                 BPF_CGROUP_INET4_POST_BIND),
9178         BPF_EAPROG_SEC("cgroup/post_bind6",     BPF_PROG_TYPE_CGROUP_SOCK,
9179                                                 BPF_CGROUP_INET6_POST_BIND),
9180         BPF_APROG_SEC("cgroup/dev",             BPF_PROG_TYPE_CGROUP_DEVICE,
9181                                                 BPF_CGROUP_DEVICE),
9182         BPF_APROG_SEC("sockops",                BPF_PROG_TYPE_SOCK_OPS,
9183                                                 BPF_CGROUP_SOCK_OPS),
9184         BPF_APROG_SEC("sk_skb/stream_parser",   BPF_PROG_TYPE_SK_SKB,
9185                                                 BPF_SK_SKB_STREAM_PARSER),
9186         BPF_APROG_SEC("sk_skb/stream_verdict",  BPF_PROG_TYPE_SK_SKB,
9187                                                 BPF_SK_SKB_STREAM_VERDICT),
9188         BPF_APROG_COMPAT("sk_skb",              BPF_PROG_TYPE_SK_SKB),
9189         BPF_APROG_SEC("sk_msg",                 BPF_PROG_TYPE_SK_MSG,
9190                                                 BPF_SK_MSG_VERDICT),
9191         BPF_APROG_SEC("lirc_mode2",             BPF_PROG_TYPE_LIRC_MODE2,
9192                                                 BPF_LIRC_MODE2),
9193         BPF_APROG_SEC("flow_dissector",         BPF_PROG_TYPE_FLOW_DISSECTOR,
9194                                                 BPF_FLOW_DISSECTOR),
9195         BPF_EAPROG_SEC("cgroup/bind4",          BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
9196                                                 BPF_CGROUP_INET4_BIND),
9197         BPF_EAPROG_SEC("cgroup/bind6",          BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
9198                                                 BPF_CGROUP_INET6_BIND),
9199         BPF_EAPROG_SEC("cgroup/connect4",       BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
9200                                                 BPF_CGROUP_INET4_CONNECT),
9201         BPF_EAPROG_SEC("cgroup/connect6",       BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
9202                                                 BPF_CGROUP_INET6_CONNECT),
9203         BPF_EAPROG_SEC("cgroup/sendmsg4",       BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
9204                                                 BPF_CGROUP_UDP4_SENDMSG),
9205         BPF_EAPROG_SEC("cgroup/sendmsg6",       BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
9206                                                 BPF_CGROUP_UDP6_SENDMSG),
9207         BPF_EAPROG_SEC("cgroup/recvmsg4",       BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
9208                                                 BPF_CGROUP_UDP4_RECVMSG),
9209         BPF_EAPROG_SEC("cgroup/recvmsg6",       BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
9210                                                 BPF_CGROUP_UDP6_RECVMSG),
9211         BPF_EAPROG_SEC("cgroup/getpeername4",   BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
9212                                                 BPF_CGROUP_INET4_GETPEERNAME),
9213         BPF_EAPROG_SEC("cgroup/getpeername6",   BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
9214                                                 BPF_CGROUP_INET6_GETPEERNAME),
9215         BPF_EAPROG_SEC("cgroup/getsockname4",   BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
9216                                                 BPF_CGROUP_INET4_GETSOCKNAME),
9217         BPF_EAPROG_SEC("cgroup/getsockname6",   BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
9218                                                 BPF_CGROUP_INET6_GETSOCKNAME),
9219         BPF_EAPROG_SEC("cgroup/sysctl",         BPF_PROG_TYPE_CGROUP_SYSCTL,
9220                                                 BPF_CGROUP_SYSCTL),
9221         BPF_EAPROG_SEC("cgroup/getsockopt",     BPF_PROG_TYPE_CGROUP_SOCKOPT,
9222                                                 BPF_CGROUP_GETSOCKOPT),
9223         BPF_EAPROG_SEC("cgroup/setsockopt",     BPF_PROG_TYPE_CGROUP_SOCKOPT,
9224                                                 BPF_CGROUP_SETSOCKOPT),
9225         BPF_PROG_SEC("struct_ops",              BPF_PROG_TYPE_STRUCT_OPS),
9226         BPF_EAPROG_SEC("sk_lookup/",            BPF_PROG_TYPE_SK_LOOKUP,
9227                                                 BPF_SK_LOOKUP),
9228 };
9229
9230 #undef BPF_PROG_SEC_IMPL
9231 #undef BPF_PROG_SEC
9232 #undef BPF_APROG_SEC
9233 #undef BPF_EAPROG_SEC
9234 #undef BPF_APROG_COMPAT
9235 #undef SEC_DEF
9236
9237 #define MAX_TYPE_NAME_SIZE 32
9238
9239 static const struct bpf_sec_def *find_sec_def(const char *sec_name)
9240 {
9241         int i, n = ARRAY_SIZE(section_defs);
9242
9243         for (i = 0; i < n; i++) {
9244                 if (strncmp(sec_name,
9245                             section_defs[i].sec, section_defs[i].len))
9246                         continue;
9247                 return &section_defs[i];
9248         }
9249         return NULL;
9250 }
9251
9252 static char *libbpf_get_type_names(bool attach_type)
9253 {
9254         int i, len = ARRAY_SIZE(section_defs) * MAX_TYPE_NAME_SIZE;
9255         char *buf;
9256
9257         buf = malloc(len);
9258         if (!buf)
9259                 return NULL;
9260
9261         buf[0] = '\0';
9262         /* Forge string buf with all available names */
9263         for (i = 0; i < ARRAY_SIZE(section_defs); i++) {
9264                 if (attach_type && !section_defs[i].is_attachable)
9265                         continue;
9266
9267                 if (strlen(buf) + strlen(section_defs[i].sec) + 2 > len) {
9268                         free(buf);
9269                         return NULL;
9270                 }
9271                 strcat(buf, " ");
9272                 strcat(buf, section_defs[i].sec);
9273         }
9274
9275         return buf;
9276 }
9277
9278 int libbpf_prog_type_by_name(const char *name, enum bpf_prog_type *prog_type,
9279                              enum bpf_attach_type *expected_attach_type)
9280 {
9281         const struct bpf_sec_def *sec_def;
9282         char *type_names;
9283
9284         if (!name)
9285                 return libbpf_err(-EINVAL);
9286
9287         sec_def = find_sec_def(name);
9288         if (sec_def) {
9289                 *prog_type = sec_def->prog_type;
9290                 *expected_attach_type = sec_def->expected_attach_type;
9291                 return 0;
9292         }
9293
9294         pr_debug("failed to guess program type from ELF section '%s'\n", name);
9295         type_names = libbpf_get_type_names(false);
9296         if (type_names != NULL) {
9297                 pr_debug("supported section(type) names are:%s\n", type_names);
9298                 free(type_names);
9299         }
9300
9301         return libbpf_err(-ESRCH);
9302 }
9303
9304 static struct bpf_map *find_struct_ops_map_by_offset(struct bpf_object *obj,
9305                                                      size_t offset)
9306 {
9307         struct bpf_map *map;
9308         size_t i;
9309
9310         for (i = 0; i < obj->nr_maps; i++) {
9311                 map = &obj->maps[i];
9312                 if (!bpf_map__is_struct_ops(map))
9313                         continue;
9314                 if (map->sec_offset <= offset &&
9315                     offset - map->sec_offset < map->def.value_size)
9316                         return map;
9317         }
9318
9319         return NULL;
9320 }
9321
9322 /* Collect the reloc from ELF and populate the st_ops->progs[] */
9323 static int bpf_object__collect_st_ops_relos(struct bpf_object *obj,
9324                                             GElf_Shdr *shdr, Elf_Data *data)
9325 {
9326         const struct btf_member *member;
9327         struct bpf_struct_ops *st_ops;
9328         struct bpf_program *prog;
9329         unsigned int shdr_idx;
9330         const struct btf *btf;
9331         struct bpf_map *map;
9332         Elf_Data *symbols;
9333         unsigned int moff, insn_idx;
9334         const char *name;
9335         __u32 member_idx;
9336         GElf_Sym sym;
9337         GElf_Rel rel;
9338         int i, nrels;
9339
9340         symbols = obj->efile.symbols;
9341         btf = obj->btf;
9342         nrels = shdr->sh_size / shdr->sh_entsize;
9343         for (i = 0; i < nrels; i++) {
9344                 if (!gelf_getrel(data, i, &rel)) {
9345                         pr_warn("struct_ops reloc: failed to get %d reloc\n", i);
9346                         return -LIBBPF_ERRNO__FORMAT;
9347                 }
9348
9349                 if (!gelf_getsym(symbols, GELF_R_SYM(rel.r_info), &sym)) {
9350                         pr_warn("struct_ops reloc: symbol %zx not found\n",
9351                                 (size_t)GELF_R_SYM(rel.r_info));
9352                         return -LIBBPF_ERRNO__FORMAT;
9353                 }
9354
9355                 name = elf_sym_str(obj, sym.st_name) ?: "<?>";
9356                 map = find_struct_ops_map_by_offset(obj, rel.r_offset);
9357                 if (!map) {
9358                         pr_warn("struct_ops reloc: cannot find map at rel.r_offset %zu\n",
9359                                 (size_t)rel.r_offset);
9360                         return -EINVAL;
9361                 }
9362
9363                 moff = rel.r_offset - map->sec_offset;
9364                 shdr_idx = sym.st_shndx;
9365                 st_ops = map->st_ops;
9366                 pr_debug("struct_ops reloc %s: for %lld value %lld shdr_idx %u rel.r_offset %zu map->sec_offset %zu name %d (\'%s\')\n",
9367                          map->name,
9368                          (long long)(rel.r_info >> 32),
9369                          (long long)sym.st_value,
9370                          shdr_idx, (size_t)rel.r_offset,
9371                          map->sec_offset, sym.st_name, name);
9372
9373                 if (shdr_idx >= SHN_LORESERVE) {
9374                         pr_warn("struct_ops reloc %s: rel.r_offset %zu shdr_idx %u unsupported non-static function\n",
9375                                 map->name, (size_t)rel.r_offset, shdr_idx);
9376                         return -LIBBPF_ERRNO__RELOC;
9377                 }
9378                 if (sym.st_value % BPF_INSN_SZ) {
9379                         pr_warn("struct_ops reloc %s: invalid target program offset %llu\n",
9380                                 map->name, (unsigned long long)sym.st_value);
9381                         return -LIBBPF_ERRNO__FORMAT;
9382                 }
9383                 insn_idx = sym.st_value / BPF_INSN_SZ;
9384
9385                 member = find_member_by_offset(st_ops->type, moff * 8);
9386                 if (!member) {
9387                         pr_warn("struct_ops reloc %s: cannot find member at moff %u\n",
9388                                 map->name, moff);
9389                         return -EINVAL;
9390                 }
9391                 member_idx = member - btf_members(st_ops->type);
9392                 name = btf__name_by_offset(btf, member->name_off);
9393
9394                 if (!resolve_func_ptr(btf, member->type, NULL)) {
9395                         pr_warn("struct_ops reloc %s: cannot relocate non func ptr %s\n",
9396                                 map->name, name);
9397                         return -EINVAL;
9398                 }
9399
9400                 prog = find_prog_by_sec_insn(obj, shdr_idx, insn_idx);
9401                 if (!prog) {
9402                         pr_warn("struct_ops reloc %s: cannot find prog at shdr_idx %u to relocate func ptr %s\n",
9403                                 map->name, shdr_idx, name);
9404                         return -EINVAL;
9405                 }
9406
9407                 if (prog->type == BPF_PROG_TYPE_UNSPEC) {
9408                         const struct bpf_sec_def *sec_def;
9409
9410                         sec_def = find_sec_def(prog->sec_name);
9411                         if (sec_def &&
9412                             sec_def->prog_type != BPF_PROG_TYPE_STRUCT_OPS) {
9413                                 /* for pr_warn */
9414                                 prog->type = sec_def->prog_type;
9415                                 goto invalid_prog;
9416                         }
9417
9418                         prog->type = BPF_PROG_TYPE_STRUCT_OPS;
9419                         prog->attach_btf_id = st_ops->type_id;
9420                         prog->expected_attach_type = member_idx;
9421                 } else if (prog->type != BPF_PROG_TYPE_STRUCT_OPS ||
9422                            prog->attach_btf_id != st_ops->type_id ||
9423                            prog->expected_attach_type != member_idx) {
9424                         goto invalid_prog;
9425                 }
9426                 st_ops->progs[member_idx] = prog;
9427         }
9428
9429         return 0;
9430
9431 invalid_prog:
9432         pr_warn("struct_ops reloc %s: cannot use prog %s in sec %s with type %u attach_btf_id %u expected_attach_type %u for func ptr %s\n",
9433                 map->name, prog->name, prog->sec_name, prog->type,
9434                 prog->attach_btf_id, prog->expected_attach_type, name);
9435         return -EINVAL;
9436 }
9437
9438 #define BTF_TRACE_PREFIX "btf_trace_"
9439 #define BTF_LSM_PREFIX "bpf_lsm_"
9440 #define BTF_ITER_PREFIX "bpf_iter_"
9441 #define BTF_MAX_NAME_SIZE 128
9442
9443 void btf_get_kernel_prefix_kind(enum bpf_attach_type attach_type,
9444                                 const char **prefix, int *kind)
9445 {
9446         switch (attach_type) {
9447         case BPF_TRACE_RAW_TP:
9448                 *prefix = BTF_TRACE_PREFIX;
9449                 *kind = BTF_KIND_TYPEDEF;
9450                 break;
9451         case BPF_LSM_MAC:
9452                 *prefix = BTF_LSM_PREFIX;
9453                 *kind = BTF_KIND_FUNC;
9454                 break;
9455         case BPF_TRACE_ITER:
9456                 *prefix = BTF_ITER_PREFIX;
9457                 *kind = BTF_KIND_FUNC;
9458                 break;
9459         default:
9460                 *prefix = "";
9461                 *kind = BTF_KIND_FUNC;
9462         }
9463 }
9464
9465 static int find_btf_by_prefix_kind(const struct btf *btf, const char *prefix,
9466                                    const char *name, __u32 kind)
9467 {
9468         char btf_type_name[BTF_MAX_NAME_SIZE];
9469         int ret;
9470
9471         ret = snprintf(btf_type_name, sizeof(btf_type_name),
9472                        "%s%s", prefix, name);
9473         /* snprintf returns the number of characters written excluding the
9474          * the terminating null. So, if >= BTF_MAX_NAME_SIZE are written, it
9475          * indicates truncation.
9476          */
9477         if (ret < 0 || ret >= sizeof(btf_type_name))
9478                 return -ENAMETOOLONG;
9479         return btf__find_by_name_kind(btf, btf_type_name, kind);
9480 }
9481
9482 static inline int find_attach_btf_id(struct btf *btf, const char *name,
9483                                      enum bpf_attach_type attach_type)
9484 {
9485         const char *prefix;
9486         int kind;
9487
9488         btf_get_kernel_prefix_kind(attach_type, &prefix, &kind);
9489         return find_btf_by_prefix_kind(btf, prefix, name, kind);
9490 }
9491
9492 int libbpf_find_vmlinux_btf_id(const char *name,
9493                                enum bpf_attach_type attach_type)
9494 {
9495         struct btf *btf;
9496         int err;
9497
9498         btf = libbpf_find_kernel_btf();
9499         err = libbpf_get_error(btf);
9500         if (err) {
9501                 pr_warn("vmlinux BTF is not found\n");
9502                 return libbpf_err(err);
9503         }
9504
9505         err = find_attach_btf_id(btf, name, attach_type);
9506         if (err <= 0)
9507                 pr_warn("%s is not found in vmlinux BTF\n", name);
9508
9509         btf__free(btf);
9510         return libbpf_err(err);
9511 }
9512
9513 static int libbpf_find_prog_btf_id(const char *name, __u32 attach_prog_fd)
9514 {
9515         struct bpf_prog_info_linear *info_linear;
9516         struct bpf_prog_info *info;
9517         struct btf *btf = NULL;
9518         int err = -EINVAL;
9519
9520         info_linear = bpf_program__get_prog_info_linear(attach_prog_fd, 0);
9521         err = libbpf_get_error(info_linear);
9522         if (err) {
9523                 pr_warn("failed get_prog_info_linear for FD %d\n",
9524                         attach_prog_fd);
9525                 return err;
9526         }
9527         info = &info_linear->info;
9528         if (!info->btf_id) {
9529                 pr_warn("The target program doesn't have BTF\n");
9530                 goto out;
9531         }
9532         if (btf__get_from_id(info->btf_id, &btf)) {
9533                 pr_warn("Failed to get BTF of the program\n");
9534                 goto out;
9535         }
9536         err = btf__find_by_name_kind(btf, name, BTF_KIND_FUNC);
9537         btf__free(btf);
9538         if (err <= 0) {
9539                 pr_warn("%s is not found in prog's BTF\n", name);
9540                 goto out;
9541         }
9542 out:
9543         free(info_linear);
9544         return err;
9545 }
9546
9547 static int find_kernel_btf_id(struct bpf_object *obj, const char *attach_name,
9548                               enum bpf_attach_type attach_type,
9549                               int *btf_obj_fd, int *btf_type_id)
9550 {
9551         int ret, i;
9552
9553         ret = find_attach_btf_id(obj->btf_vmlinux, attach_name, attach_type);
9554         if (ret > 0) {
9555                 *btf_obj_fd = 0; /* vmlinux BTF */
9556                 *btf_type_id = ret;
9557                 return 0;
9558         }
9559         if (ret != -ENOENT)
9560                 return ret;
9561
9562         ret = load_module_btfs(obj);
9563         if (ret)
9564                 return ret;
9565
9566         for (i = 0; i < obj->btf_module_cnt; i++) {
9567                 const struct module_btf *mod = &obj->btf_modules[i];
9568
9569                 ret = find_attach_btf_id(mod->btf, attach_name, attach_type);
9570                 if (ret > 0) {
9571                         *btf_obj_fd = mod->fd;
9572                         *btf_type_id = ret;
9573                         return 0;
9574                 }
9575                 if (ret == -ENOENT)
9576                         continue;
9577
9578                 return ret;
9579         }
9580
9581         return -ESRCH;
9582 }
9583
9584 static int libbpf_find_attach_btf_id(struct bpf_program *prog, int *btf_obj_fd, int *btf_type_id)
9585 {
9586         enum bpf_attach_type attach_type = prog->expected_attach_type;
9587         __u32 attach_prog_fd = prog->attach_prog_fd;
9588         const char *name = prog->sec_name, *attach_name;
9589         const struct bpf_sec_def *sec = NULL;
9590         int i, err = 0;
9591
9592         if (!name)
9593                 return -EINVAL;
9594
9595         for (i = 0; i < ARRAY_SIZE(section_defs); i++) {
9596                 if (!section_defs[i].is_attach_btf)
9597                         continue;
9598                 if (strncmp(name, section_defs[i].sec, section_defs[i].len))
9599                         continue;
9600
9601                 sec = &section_defs[i];
9602                 break;
9603         }
9604
9605         if (!sec) {
9606                 pr_warn("failed to identify BTF ID based on ELF section name '%s'\n", name);
9607                 return -ESRCH;
9608         }
9609         attach_name = name + sec->len;
9610
9611         /* BPF program's BTF ID */
9612         if (attach_prog_fd) {
9613                 err = libbpf_find_prog_btf_id(attach_name, attach_prog_fd);
9614                 if (err < 0) {
9615                         pr_warn("failed to find BPF program (FD %d) BTF ID for '%s': %d\n",
9616                                  attach_prog_fd, attach_name, err);
9617                         return err;
9618                 }
9619                 *btf_obj_fd = 0;
9620                 *btf_type_id = err;
9621                 return 0;
9622         }
9623
9624         /* kernel/module BTF ID */
9625         if (prog->obj->gen_loader) {
9626                 bpf_gen__record_attach_target(prog->obj->gen_loader, attach_name, attach_type);
9627                 *btf_obj_fd = 0;
9628                 *btf_type_id = 1;
9629         } else {
9630                 err = find_kernel_btf_id(prog->obj, attach_name, attach_type, btf_obj_fd, btf_type_id);
9631         }
9632         if (err) {
9633                 pr_warn("failed to find kernel BTF type ID of '%s': %d\n", attach_name, err);
9634                 return err;
9635         }
9636         return 0;
9637 }
9638
9639 int libbpf_attach_type_by_name(const char *name,
9640                                enum bpf_attach_type *attach_type)
9641 {
9642         char *type_names;
9643         int i;
9644
9645         if (!name)
9646                 return libbpf_err(-EINVAL);
9647
9648         for (i = 0; i < ARRAY_SIZE(section_defs); i++) {
9649                 if (strncmp(name, section_defs[i].sec, section_defs[i].len))
9650                         continue;
9651                 if (!section_defs[i].is_attachable)
9652                         return libbpf_err(-EINVAL);
9653                 *attach_type = section_defs[i].expected_attach_type;
9654                 return 0;
9655         }
9656         pr_debug("failed to guess attach type based on ELF section name '%s'\n", name);
9657         type_names = libbpf_get_type_names(true);
9658         if (type_names != NULL) {
9659                 pr_debug("attachable section(type) names are:%s\n", type_names);
9660                 free(type_names);
9661         }
9662
9663         return libbpf_err(-EINVAL);
9664 }
9665
9666 int bpf_map__fd(const struct bpf_map *map)
9667 {
9668         return map ? map->fd : libbpf_err(-EINVAL);
9669 }
9670
9671 const struct bpf_map_def *bpf_map__def(const struct bpf_map *map)
9672 {
9673         return map ? &map->def : libbpf_err_ptr(-EINVAL);
9674 }
9675
9676 const char *bpf_map__name(const struct bpf_map *map)
9677 {
9678         return map ? map->name : NULL;
9679 }
9680
9681 enum bpf_map_type bpf_map__type(const struct bpf_map *map)
9682 {
9683         return map->def.type;
9684 }
9685
9686 int bpf_map__set_type(struct bpf_map *map, enum bpf_map_type type)
9687 {
9688         if (map->fd >= 0)
9689                 return libbpf_err(-EBUSY);
9690         map->def.type = type;
9691         return 0;
9692 }
9693
9694 __u32 bpf_map__map_flags(const struct bpf_map *map)
9695 {
9696         return map->def.map_flags;
9697 }
9698
9699 int bpf_map__set_map_flags(struct bpf_map *map, __u32 flags)
9700 {
9701         if (map->fd >= 0)
9702                 return libbpf_err(-EBUSY);
9703         map->def.map_flags = flags;
9704         return 0;
9705 }
9706
9707 __u32 bpf_map__numa_node(const struct bpf_map *map)
9708 {
9709         return map->numa_node;
9710 }
9711
9712 int bpf_map__set_numa_node(struct bpf_map *map, __u32 numa_node)
9713 {
9714         if (map->fd >= 0)
9715                 return libbpf_err(-EBUSY);
9716         map->numa_node = numa_node;
9717         return 0;
9718 }
9719
9720 __u32 bpf_map__key_size(const struct bpf_map *map)
9721 {
9722         return map->def.key_size;
9723 }
9724
9725 int bpf_map__set_key_size(struct bpf_map *map, __u32 size)
9726 {
9727         if (map->fd >= 0)
9728                 return libbpf_err(-EBUSY);
9729         map->def.key_size = size;
9730         return 0;
9731 }
9732
9733 __u32 bpf_map__value_size(const struct bpf_map *map)
9734 {
9735         return map->def.value_size;
9736 }
9737
9738 int bpf_map__set_value_size(struct bpf_map *map, __u32 size)
9739 {
9740         if (map->fd >= 0)
9741                 return libbpf_err(-EBUSY);
9742         map->def.value_size = size;
9743         return 0;
9744 }
9745
9746 __u32 bpf_map__btf_key_type_id(const struct bpf_map *map)
9747 {
9748         return map ? map->btf_key_type_id : 0;
9749 }
9750
9751 __u32 bpf_map__btf_value_type_id(const struct bpf_map *map)
9752 {
9753         return map ? map->btf_value_type_id : 0;
9754 }
9755
9756 int bpf_map__set_priv(struct bpf_map *map, void *priv,
9757                      bpf_map_clear_priv_t clear_priv)
9758 {
9759         if (!map)
9760                 return libbpf_err(-EINVAL);
9761
9762         if (map->priv) {
9763                 if (map->clear_priv)
9764                         map->clear_priv(map, map->priv);
9765         }
9766
9767         map->priv = priv;
9768         map->clear_priv = clear_priv;
9769         return 0;
9770 }
9771
9772 void *bpf_map__priv(const struct bpf_map *map)
9773 {
9774         return map ? map->priv : libbpf_err_ptr(-EINVAL);
9775 }
9776
9777 int bpf_map__set_initial_value(struct bpf_map *map,
9778                                const void *data, size_t size)
9779 {
9780         if (!map->mmaped || map->libbpf_type == LIBBPF_MAP_KCONFIG ||
9781             size != map->def.value_size || map->fd >= 0)
9782                 return libbpf_err(-EINVAL);
9783
9784         memcpy(map->mmaped, data, size);
9785         return 0;
9786 }
9787
9788 const void *bpf_map__initial_value(struct bpf_map *map, size_t *psize)
9789 {
9790         if (!map->mmaped)
9791                 return NULL;
9792         *psize = map->def.value_size;
9793         return map->mmaped;
9794 }
9795
9796 bool bpf_map__is_offload_neutral(const struct bpf_map *map)
9797 {
9798         return map->def.type == BPF_MAP_TYPE_PERF_EVENT_ARRAY;
9799 }
9800
9801 bool bpf_map__is_internal(const struct bpf_map *map)
9802 {
9803         return map->libbpf_type != LIBBPF_MAP_UNSPEC;
9804 }
9805
9806 __u32 bpf_map__ifindex(const struct bpf_map *map)
9807 {
9808         return map->map_ifindex;
9809 }
9810
9811 int bpf_map__set_ifindex(struct bpf_map *map, __u32 ifindex)
9812 {
9813         if (map->fd >= 0)
9814                 return libbpf_err(-EBUSY);
9815         map->map_ifindex = ifindex;
9816         return 0;
9817 }
9818
9819 int bpf_map__set_inner_map_fd(struct bpf_map *map, int fd)
9820 {
9821         if (!bpf_map_type__is_map_in_map(map->def.type)) {
9822                 pr_warn("error: unsupported map type\n");
9823                 return libbpf_err(-EINVAL);
9824         }
9825         if (map->inner_map_fd != -1) {
9826                 pr_warn("error: inner_map_fd already specified\n");
9827                 return libbpf_err(-EINVAL);
9828         }
9829         zfree(&map->inner_map);
9830         map->inner_map_fd = fd;
9831         return 0;
9832 }
9833
9834 static struct bpf_map *
9835 __bpf_map__iter(const struct bpf_map *m, const struct bpf_object *obj, int i)
9836 {
9837         ssize_t idx;
9838         struct bpf_map *s, *e;
9839
9840         if (!obj || !obj->maps)
9841                 return errno = EINVAL, NULL;
9842
9843         s = obj->maps;
9844         e = obj->maps + obj->nr_maps;
9845
9846         if ((m < s) || (m >= e)) {
9847                 pr_warn("error in %s: map handler doesn't belong to object\n",
9848                          __func__);
9849                 return errno = EINVAL, NULL;
9850         }
9851
9852         idx = (m - obj->maps) + i;
9853         if (idx >= obj->nr_maps || idx < 0)
9854                 return NULL;
9855         return &obj->maps[idx];
9856 }
9857
9858 struct bpf_map *
9859 bpf_map__next(const struct bpf_map *prev, const struct bpf_object *obj)
9860 {
9861         if (prev == NULL)
9862                 return obj->maps;
9863
9864         return __bpf_map__iter(prev, obj, 1);
9865 }
9866
9867 struct bpf_map *
9868 bpf_map__prev(const struct bpf_map *next, const struct bpf_object *obj)
9869 {
9870         if (next == NULL) {
9871                 if (!obj->nr_maps)
9872                         return NULL;
9873                 return obj->maps + obj->nr_maps - 1;
9874         }
9875
9876         return __bpf_map__iter(next, obj, -1);
9877 }
9878
9879 struct bpf_map *
9880 bpf_object__find_map_by_name(const struct bpf_object *obj, const char *name)
9881 {
9882         struct bpf_map *pos;
9883
9884         bpf_object__for_each_map(pos, obj) {
9885                 if (pos->name && !strcmp(pos->name, name))
9886                         return pos;
9887         }
9888         return errno = ENOENT, NULL;
9889 }
9890
9891 int
9892 bpf_object__find_map_fd_by_name(const struct bpf_object *obj, const char *name)
9893 {
9894         return bpf_map__fd(bpf_object__find_map_by_name(obj, name));
9895 }
9896
9897 struct bpf_map *
9898 bpf_object__find_map_by_offset(struct bpf_object *obj, size_t offset)
9899 {
9900         return libbpf_err_ptr(-ENOTSUP);
9901 }
9902
9903 long libbpf_get_error(const void *ptr)
9904 {
9905         if (!IS_ERR_OR_NULL(ptr))
9906                 return 0;
9907
9908         if (IS_ERR(ptr))
9909                 errno = -PTR_ERR(ptr);
9910
9911         /* If ptr == NULL, then errno should be already set by the failing
9912          * API, because libbpf never returns NULL on success and it now always
9913          * sets errno on error. So no extra errno handling for ptr == NULL
9914          * case.
9915          */
9916         return -errno;
9917 }
9918
9919 int bpf_prog_load(const char *file, enum bpf_prog_type type,
9920                   struct bpf_object **pobj, int *prog_fd)
9921 {
9922         struct bpf_prog_load_attr attr;
9923
9924         memset(&attr, 0, sizeof(struct bpf_prog_load_attr));
9925         attr.file = file;
9926         attr.prog_type = type;
9927         attr.expected_attach_type = 0;
9928
9929         return bpf_prog_load_xattr(&attr, pobj, prog_fd);
9930 }
9931
9932 int bpf_prog_load_xattr(const struct bpf_prog_load_attr *attr,
9933                         struct bpf_object **pobj, int *prog_fd)
9934 {
9935         struct bpf_object_open_attr open_attr = {};
9936         struct bpf_program *prog, *first_prog = NULL;
9937         struct bpf_object *obj;
9938         struct bpf_map *map;
9939         int err;
9940
9941         if (!attr)
9942                 return libbpf_err(-EINVAL);
9943         if (!attr->file)
9944                 return libbpf_err(-EINVAL);
9945
9946         open_attr.file = attr->file;
9947         open_attr.prog_type = attr->prog_type;
9948
9949         obj = bpf_object__open_xattr(&open_attr);
9950         err = libbpf_get_error(obj);
9951         if (err)
9952                 return libbpf_err(-ENOENT);
9953
9954         bpf_object__for_each_program(prog, obj) {
9955                 enum bpf_attach_type attach_type = attr->expected_attach_type;
9956                 /*
9957                  * to preserve backwards compatibility, bpf_prog_load treats
9958                  * attr->prog_type, if specified, as an override to whatever
9959                  * bpf_object__open guessed
9960                  */
9961                 if (attr->prog_type != BPF_PROG_TYPE_UNSPEC) {
9962                         bpf_program__set_type(prog, attr->prog_type);
9963                         bpf_program__set_expected_attach_type(prog,
9964                                                               attach_type);
9965                 }
9966                 if (bpf_program__get_type(prog) == BPF_PROG_TYPE_UNSPEC) {
9967                         /*
9968                          * we haven't guessed from section name and user
9969                          * didn't provide a fallback type, too bad...
9970                          */
9971                         bpf_object__close(obj);
9972                         return libbpf_err(-EINVAL);
9973                 }
9974
9975                 prog->prog_ifindex = attr->ifindex;
9976                 prog->log_level = attr->log_level;
9977                 prog->prog_flags |= attr->prog_flags;
9978                 if (!first_prog)
9979                         first_prog = prog;
9980         }
9981
9982         bpf_object__for_each_map(map, obj) {
9983                 if (!bpf_map__is_offload_neutral(map))
9984                         map->map_ifindex = attr->ifindex;
9985         }
9986
9987         if (!first_prog) {
9988                 pr_warn("object file doesn't contain bpf program\n");
9989                 bpf_object__close(obj);
9990                 return libbpf_err(-ENOENT);
9991         }
9992
9993         err = bpf_object__load(obj);
9994         if (err) {
9995                 bpf_object__close(obj);
9996                 return libbpf_err(err);
9997         }
9998
9999         *pobj = obj;
10000         *prog_fd = bpf_program__fd(first_prog);
10001         return 0;
10002 }
10003
10004 struct bpf_link {
10005         int (*detach)(struct bpf_link *link);
10006         int (*destroy)(struct bpf_link *link);
10007         char *pin_path;         /* NULL, if not pinned */
10008         int fd;                 /* hook FD, -1 if not applicable */
10009         bool disconnected;
10010 };
10011
10012 /* Replace link's underlying BPF program with the new one */
10013 int bpf_link__update_program(struct bpf_link *link, struct bpf_program *prog)
10014 {
10015         int ret;
10016
10017         ret = bpf_link_update(bpf_link__fd(link), bpf_program__fd(prog), NULL);
10018         return libbpf_err_errno(ret);
10019 }
10020
10021 /* Release "ownership" of underlying BPF resource (typically, BPF program
10022  * attached to some BPF hook, e.g., tracepoint, kprobe, etc). Disconnected
10023  * link, when destructed through bpf_link__destroy() call won't attempt to
10024  * detach/unregisted that BPF resource. This is useful in situations where,
10025  * say, attached BPF program has to outlive userspace program that attached it
10026  * in the system. Depending on type of BPF program, though, there might be
10027  * additional steps (like pinning BPF program in BPF FS) necessary to ensure
10028  * exit of userspace program doesn't trigger automatic detachment and clean up
10029  * inside the kernel.
10030  */
10031 void bpf_link__disconnect(struct bpf_link *link)
10032 {
10033         link->disconnected = true;
10034 }
10035
10036 int bpf_link__destroy(struct bpf_link *link)
10037 {
10038         int err = 0;
10039
10040         if (IS_ERR_OR_NULL(link))
10041                 return 0;
10042
10043         if (!link->disconnected && link->detach)
10044                 err = link->detach(link);
10045         if (link->destroy)
10046                 link->destroy(link);
10047         if (link->pin_path)
10048                 free(link->pin_path);
10049         free(link);
10050
10051         return libbpf_err(err);
10052 }
10053
10054 int bpf_link__fd(const struct bpf_link *link)
10055 {
10056         return link->fd;
10057 }
10058
10059 const char *bpf_link__pin_path(const struct bpf_link *link)
10060 {
10061         return link->pin_path;
10062 }
10063
10064 static int bpf_link__detach_fd(struct bpf_link *link)
10065 {
10066         return libbpf_err_errno(close(link->fd));
10067 }
10068
10069 struct bpf_link *bpf_link__open(const char *path)
10070 {
10071         struct bpf_link *link;
10072         int fd;
10073
10074         fd = bpf_obj_get(path);
10075         if (fd < 0) {
10076                 fd = -errno;
10077                 pr_warn("failed to open link at %s: %d\n", path, fd);
10078                 return libbpf_err_ptr(fd);
10079         }
10080
10081         link = calloc(1, sizeof(*link));
10082         if (!link) {
10083                 close(fd);
10084                 return libbpf_err_ptr(-ENOMEM);
10085         }
10086         link->detach = &bpf_link__detach_fd;
10087         link->fd = fd;
10088
10089         link->pin_path = strdup(path);
10090         if (!link->pin_path) {
10091                 bpf_link__destroy(link);
10092                 return libbpf_err_ptr(-ENOMEM);
10093         }
10094
10095         return link;
10096 }
10097
10098 int bpf_link__detach(struct bpf_link *link)
10099 {
10100         return bpf_link_detach(link->fd) ? -errno : 0;
10101 }
10102
10103 int bpf_link__pin(struct bpf_link *link, const char *path)
10104 {
10105         int err;
10106
10107         if (link->pin_path)
10108                 return libbpf_err(-EBUSY);
10109         err = make_parent_dir(path);
10110         if (err)
10111                 return libbpf_err(err);
10112         err = check_path(path);
10113         if (err)
10114                 return libbpf_err(err);
10115
10116         link->pin_path = strdup(path);
10117         if (!link->pin_path)
10118                 return libbpf_err(-ENOMEM);
10119
10120         if (bpf_obj_pin(link->fd, link->pin_path)) {
10121                 err = -errno;
10122                 zfree(&link->pin_path);
10123                 return libbpf_err(err);
10124         }
10125
10126         pr_debug("link fd=%d: pinned at %s\n", link->fd, link->pin_path);
10127         return 0;
10128 }
10129
10130 int bpf_link__unpin(struct bpf_link *link)
10131 {
10132         int err;
10133
10134         if (!link->pin_path)
10135                 return libbpf_err(-EINVAL);
10136
10137         err = unlink(link->pin_path);
10138         if (err != 0)
10139                 return libbpf_err_errno(err);
10140
10141         pr_debug("link fd=%d: unpinned from %s\n", link->fd, link->pin_path);
10142         zfree(&link->pin_path);
10143         return 0;
10144 }
10145
10146 static int bpf_link__detach_perf_event(struct bpf_link *link)
10147 {
10148         int err;
10149
10150         err = ioctl(link->fd, PERF_EVENT_IOC_DISABLE, 0);
10151         if (err)
10152                 err = -errno;
10153
10154         close(link->fd);
10155         return libbpf_err(err);
10156 }
10157
10158 struct bpf_link *bpf_program__attach_perf_event(struct bpf_program *prog, int pfd)
10159 {
10160         char errmsg[STRERR_BUFSIZE];
10161         struct bpf_link *link;
10162         int prog_fd, err;
10163
10164         if (pfd < 0) {
10165                 pr_warn("prog '%s': invalid perf event FD %d\n",
10166                         prog->name, pfd);
10167                 return libbpf_err_ptr(-EINVAL);
10168         }
10169         prog_fd = bpf_program__fd(prog);
10170         if (prog_fd < 0) {
10171                 pr_warn("prog '%s': can't attach BPF program w/o FD (did you load it?)\n",
10172                         prog->name);
10173                 return libbpf_err_ptr(-EINVAL);
10174         }
10175
10176         link = calloc(1, sizeof(*link));
10177         if (!link)
10178                 return libbpf_err_ptr(-ENOMEM);
10179         link->detach = &bpf_link__detach_perf_event;
10180         link->fd = pfd;
10181
10182         if (ioctl(pfd, PERF_EVENT_IOC_SET_BPF, prog_fd) < 0) {
10183                 err = -errno;
10184                 free(link);
10185                 pr_warn("prog '%s': failed to attach to pfd %d: %s\n",
10186                         prog->name, pfd, libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
10187                 if (err == -EPROTO)
10188                         pr_warn("prog '%s': try add PERF_SAMPLE_CALLCHAIN to or remove exclude_callchain_[kernel|user] from pfd %d\n",
10189                                 prog->name, pfd);
10190                 return libbpf_err_ptr(err);
10191         }
10192         if (ioctl(pfd, PERF_EVENT_IOC_ENABLE, 0) < 0) {
10193                 err = -errno;
10194                 free(link);
10195                 pr_warn("prog '%s': failed to enable pfd %d: %s\n",
10196                         prog->name, pfd, libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
10197                 return libbpf_err_ptr(err);
10198         }
10199         return link;
10200 }
10201
10202 /*
10203  * this function is expected to parse integer in the range of [0, 2^31-1] from
10204  * given file using scanf format string fmt. If actual parsed value is
10205  * negative, the result might be indistinguishable from error
10206  */
10207 static int parse_uint_from_file(const char *file, const char *fmt)
10208 {
10209         char buf[STRERR_BUFSIZE];
10210         int err, ret;
10211         FILE *f;
10212
10213         f = fopen(file, "r");
10214         if (!f) {
10215                 err = -errno;
10216                 pr_debug("failed to open '%s': %s\n", file,
10217                          libbpf_strerror_r(err, buf, sizeof(buf)));
10218                 return err;
10219         }
10220         err = fscanf(f, fmt, &ret);
10221         if (err != 1) {
10222                 err = err == EOF ? -EIO : -errno;
10223                 pr_debug("failed to parse '%s': %s\n", file,
10224                         libbpf_strerror_r(err, buf, sizeof(buf)));
10225                 fclose(f);
10226                 return err;
10227         }
10228         fclose(f);
10229         return ret;
10230 }
10231
10232 static int determine_kprobe_perf_type(void)
10233 {
10234         const char *file = "/sys/bus/event_source/devices/kprobe/type";
10235
10236         return parse_uint_from_file(file, "%d\n");
10237 }
10238
10239 static int determine_uprobe_perf_type(void)
10240 {
10241         const char *file = "/sys/bus/event_source/devices/uprobe/type";
10242
10243         return parse_uint_from_file(file, "%d\n");
10244 }
10245
10246 static int determine_kprobe_retprobe_bit(void)
10247 {
10248         const char *file = "/sys/bus/event_source/devices/kprobe/format/retprobe";
10249
10250         return parse_uint_from_file(file, "config:%d\n");
10251 }
10252
10253 static int determine_uprobe_retprobe_bit(void)
10254 {
10255         const char *file = "/sys/bus/event_source/devices/uprobe/format/retprobe";
10256
10257         return parse_uint_from_file(file, "config:%d\n");
10258 }
10259
10260 static int perf_event_open_probe(bool uprobe, bool retprobe, const char *name,
10261                                  uint64_t offset, int pid)
10262 {
10263         struct perf_event_attr attr = {};
10264         char errmsg[STRERR_BUFSIZE];
10265         int type, pfd, err;
10266
10267         type = uprobe ? determine_uprobe_perf_type()
10268                       : determine_kprobe_perf_type();
10269         if (type < 0) {
10270                 pr_warn("failed to determine %s perf type: %s\n",
10271                         uprobe ? "uprobe" : "kprobe",
10272                         libbpf_strerror_r(type, errmsg, sizeof(errmsg)));
10273                 return type;
10274         }
10275         if (retprobe) {
10276                 int bit = uprobe ? determine_uprobe_retprobe_bit()
10277                                  : determine_kprobe_retprobe_bit();
10278
10279                 if (bit < 0) {
10280                         pr_warn("failed to determine %s retprobe bit: %s\n",
10281                                 uprobe ? "uprobe" : "kprobe",
10282                                 libbpf_strerror_r(bit, errmsg, sizeof(errmsg)));
10283                         return bit;
10284                 }
10285                 attr.config |= 1 << bit;
10286         }
10287         attr.size = sizeof(attr);
10288         attr.type = type;
10289         attr.config1 = ptr_to_u64(name); /* kprobe_func or uprobe_path */
10290         attr.config2 = offset;           /* kprobe_addr or probe_offset */
10291
10292         /* pid filter is meaningful only for uprobes */
10293         pfd = syscall(__NR_perf_event_open, &attr,
10294                       pid < 0 ? -1 : pid /* pid */,
10295                       pid == -1 ? 0 : -1 /* cpu */,
10296                       -1 /* group_fd */, PERF_FLAG_FD_CLOEXEC);
10297         if (pfd < 0) {
10298                 err = -errno;
10299                 pr_warn("%s perf_event_open() failed: %s\n",
10300                         uprobe ? "uprobe" : "kprobe",
10301                         libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
10302                 return err;
10303         }
10304         return pfd;
10305 }
10306
10307 struct bpf_link *bpf_program__attach_kprobe(struct bpf_program *prog,
10308                                             bool retprobe,
10309                                             const char *func_name)
10310 {
10311         char errmsg[STRERR_BUFSIZE];
10312         struct bpf_link *link;
10313         int pfd, err;
10314
10315         pfd = perf_event_open_probe(false /* uprobe */, retprobe, func_name,
10316                                     0 /* offset */, -1 /* pid */);
10317         if (pfd < 0) {
10318                 pr_warn("prog '%s': failed to create %s '%s' perf event: %s\n",
10319                         prog->name, retprobe ? "kretprobe" : "kprobe", func_name,
10320                         libbpf_strerror_r(pfd, errmsg, sizeof(errmsg)));
10321                 return libbpf_err_ptr(pfd);
10322         }
10323         link = bpf_program__attach_perf_event(prog, pfd);
10324         err = libbpf_get_error(link);
10325         if (err) {
10326                 close(pfd);
10327                 pr_warn("prog '%s': failed to attach to %s '%s': %s\n",
10328                         prog->name, retprobe ? "kretprobe" : "kprobe", func_name,
10329                         libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
10330                 return libbpf_err_ptr(err);
10331         }
10332         return link;
10333 }
10334
10335 static struct bpf_link *attach_kprobe(const struct bpf_sec_def *sec,
10336                                       struct bpf_program *prog)
10337 {
10338         const char *func_name;
10339         bool retprobe;
10340
10341         func_name = prog->sec_name + sec->len;
10342         retprobe = strcmp(sec->sec, "kretprobe/") == 0;
10343
10344         return bpf_program__attach_kprobe(prog, retprobe, func_name);
10345 }
10346
10347 struct bpf_link *bpf_program__attach_uprobe(struct bpf_program *prog,
10348                                             bool retprobe, pid_t pid,
10349                                             const char *binary_path,
10350                                             size_t func_offset)
10351 {
10352         char errmsg[STRERR_BUFSIZE];
10353         struct bpf_link *link;
10354         int pfd, err;
10355
10356         pfd = perf_event_open_probe(true /* uprobe */, retprobe,
10357                                     binary_path, func_offset, pid);
10358         if (pfd < 0) {
10359                 pr_warn("prog '%s': failed to create %s '%s:0x%zx' perf event: %s\n",
10360                         prog->name, retprobe ? "uretprobe" : "uprobe",
10361                         binary_path, func_offset,
10362                         libbpf_strerror_r(pfd, errmsg, sizeof(errmsg)));
10363                 return libbpf_err_ptr(pfd);
10364         }
10365         link = bpf_program__attach_perf_event(prog, pfd);
10366         err = libbpf_get_error(link);
10367         if (err) {
10368                 close(pfd);
10369                 pr_warn("prog '%s': failed to attach to %s '%s:0x%zx': %s\n",
10370                         prog->name, retprobe ? "uretprobe" : "uprobe",
10371                         binary_path, func_offset,
10372                         libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
10373                 return libbpf_err_ptr(err);
10374         }
10375         return link;
10376 }
10377
10378 static int determine_tracepoint_id(const char *tp_category,
10379                                    const char *tp_name)
10380 {
10381         char file[PATH_MAX];
10382         int ret;
10383
10384         ret = snprintf(file, sizeof(file),
10385                        "/sys/kernel/debug/tracing/events/%s/%s/id",
10386                        tp_category, tp_name);
10387         if (ret < 0)
10388                 return -errno;
10389         if (ret >= sizeof(file)) {
10390                 pr_debug("tracepoint %s/%s path is too long\n",
10391                          tp_category, tp_name);
10392                 return -E2BIG;
10393         }
10394         return parse_uint_from_file(file, "%d\n");
10395 }
10396
10397 static int perf_event_open_tracepoint(const char *tp_category,
10398                                       const char *tp_name)
10399 {
10400         struct perf_event_attr attr = {};
10401         char errmsg[STRERR_BUFSIZE];
10402         int tp_id, pfd, err;
10403
10404         tp_id = determine_tracepoint_id(tp_category, tp_name);
10405         if (tp_id < 0) {
10406                 pr_warn("failed to determine tracepoint '%s/%s' perf event ID: %s\n",
10407                         tp_category, tp_name,
10408                         libbpf_strerror_r(tp_id, errmsg, sizeof(errmsg)));
10409                 return tp_id;
10410         }
10411
10412         attr.type = PERF_TYPE_TRACEPOINT;
10413         attr.size = sizeof(attr);
10414         attr.config = tp_id;
10415
10416         pfd = syscall(__NR_perf_event_open, &attr, -1 /* pid */, 0 /* cpu */,
10417                       -1 /* group_fd */, PERF_FLAG_FD_CLOEXEC);
10418         if (pfd < 0) {
10419                 err = -errno;
10420                 pr_warn("tracepoint '%s/%s' perf_event_open() failed: %s\n",
10421                         tp_category, tp_name,
10422                         libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
10423                 return err;
10424         }
10425         return pfd;
10426 }
10427
10428 struct bpf_link *bpf_program__attach_tracepoint(struct bpf_program *prog,
10429                                                 const char *tp_category,
10430                                                 const char *tp_name)
10431 {
10432         char errmsg[STRERR_BUFSIZE];
10433         struct bpf_link *link;
10434         int pfd, err;
10435
10436         pfd = perf_event_open_tracepoint(tp_category, tp_name);
10437         if (pfd < 0) {
10438                 pr_warn("prog '%s': failed to create tracepoint '%s/%s' perf event: %s\n",
10439                         prog->name, tp_category, tp_name,
10440                         libbpf_strerror_r(pfd, errmsg, sizeof(errmsg)));
10441                 return libbpf_err_ptr(pfd);
10442         }
10443         link = bpf_program__attach_perf_event(prog, pfd);
10444         err = libbpf_get_error(link);
10445         if (err) {
10446                 close(pfd);
10447                 pr_warn("prog '%s': failed to attach to tracepoint '%s/%s': %s\n",
10448                         prog->name, tp_category, tp_name,
10449                         libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
10450                 return libbpf_err_ptr(err);
10451         }
10452         return link;
10453 }
10454
10455 static struct bpf_link *attach_tp(const struct bpf_sec_def *sec,
10456                                   struct bpf_program *prog)
10457 {
10458         char *sec_name, *tp_cat, *tp_name;
10459         struct bpf_link *link;
10460
10461         sec_name = strdup(prog->sec_name);
10462         if (!sec_name)
10463                 return libbpf_err_ptr(-ENOMEM);
10464
10465         /* extract "tp/<category>/<name>" */
10466         tp_cat = sec_name + sec->len;
10467         tp_name = strchr(tp_cat, '/');
10468         if (!tp_name) {
10469                 free(sec_name);
10470                 return libbpf_err_ptr(-EINVAL);
10471         }
10472         *tp_name = '\0';
10473         tp_name++;
10474
10475         link = bpf_program__attach_tracepoint(prog, tp_cat, tp_name);
10476         free(sec_name);
10477         return link;
10478 }
10479
10480 struct bpf_link *bpf_program__attach_raw_tracepoint(struct bpf_program *prog,
10481                                                     const char *tp_name)
10482 {
10483         char errmsg[STRERR_BUFSIZE];
10484         struct bpf_link *link;
10485         int prog_fd, pfd;
10486
10487         prog_fd = bpf_program__fd(prog);
10488         if (prog_fd < 0) {
10489                 pr_warn("prog '%s': can't attach before loaded\n", prog->name);
10490                 return libbpf_err_ptr(-EINVAL);
10491         }
10492
10493         link = calloc(1, sizeof(*link));
10494         if (!link)
10495                 return libbpf_err_ptr(-ENOMEM);
10496         link->detach = &bpf_link__detach_fd;
10497
10498         pfd = bpf_raw_tracepoint_open(tp_name, prog_fd);
10499         if (pfd < 0) {
10500                 pfd = -errno;
10501                 free(link);
10502                 pr_warn("prog '%s': failed to attach to raw tracepoint '%s': %s\n",
10503                         prog->name, tp_name, libbpf_strerror_r(pfd, errmsg, sizeof(errmsg)));
10504                 return libbpf_err_ptr(pfd);
10505         }
10506         link->fd = pfd;
10507         return link;
10508 }
10509
10510 static struct bpf_link *attach_raw_tp(const struct bpf_sec_def *sec,
10511                                       struct bpf_program *prog)
10512 {
10513         const char *tp_name = prog->sec_name + sec->len;
10514
10515         return bpf_program__attach_raw_tracepoint(prog, tp_name);
10516 }
10517
10518 /* Common logic for all BPF program types that attach to a btf_id */
10519 static struct bpf_link *bpf_program__attach_btf_id(struct bpf_program *prog)
10520 {
10521         char errmsg[STRERR_BUFSIZE];
10522         struct bpf_link *link;
10523         int prog_fd, pfd;
10524
10525         prog_fd = bpf_program__fd(prog);
10526         if (prog_fd < 0) {
10527                 pr_warn("prog '%s': can't attach before loaded\n", prog->name);
10528                 return libbpf_err_ptr(-EINVAL);
10529         }
10530
10531         link = calloc(1, sizeof(*link));
10532         if (!link)
10533                 return libbpf_err_ptr(-ENOMEM);
10534         link->detach = &bpf_link__detach_fd;
10535
10536         pfd = bpf_raw_tracepoint_open(NULL, prog_fd);
10537         if (pfd < 0) {
10538                 pfd = -errno;
10539                 free(link);
10540                 pr_warn("prog '%s': failed to attach: %s\n",
10541                         prog->name, libbpf_strerror_r(pfd, errmsg, sizeof(errmsg)));
10542                 return libbpf_err_ptr(pfd);
10543         }
10544         link->fd = pfd;
10545         return (struct bpf_link *)link;
10546 }
10547
10548 struct bpf_link *bpf_program__attach_trace(struct bpf_program *prog)
10549 {
10550         return bpf_program__attach_btf_id(prog);
10551 }
10552
10553 struct bpf_link *bpf_program__attach_lsm(struct bpf_program *prog)
10554 {
10555         return bpf_program__attach_btf_id(prog);
10556 }
10557
10558 static struct bpf_link *attach_trace(const struct bpf_sec_def *sec,
10559                                      struct bpf_program *prog)
10560 {
10561         return bpf_program__attach_trace(prog);
10562 }
10563
10564 static struct bpf_link *attach_lsm(const struct bpf_sec_def *sec,
10565                                    struct bpf_program *prog)
10566 {
10567         return bpf_program__attach_lsm(prog);
10568 }
10569
10570 static struct bpf_link *
10571 bpf_program__attach_fd(struct bpf_program *prog, int target_fd, int btf_id,
10572                        const char *target_name)
10573 {
10574         DECLARE_LIBBPF_OPTS(bpf_link_create_opts, opts,
10575                             .target_btf_id = btf_id);
10576         enum bpf_attach_type attach_type;
10577         char errmsg[STRERR_BUFSIZE];
10578         struct bpf_link *link;
10579         int prog_fd, link_fd;
10580
10581         prog_fd = bpf_program__fd(prog);
10582         if (prog_fd < 0) {
10583                 pr_warn("prog '%s': can't attach before loaded\n", prog->name);
10584                 return libbpf_err_ptr(-EINVAL);
10585         }
10586
10587         link = calloc(1, sizeof(*link));
10588         if (!link)
10589                 return libbpf_err_ptr(-ENOMEM);
10590         link->detach = &bpf_link__detach_fd;
10591
10592         attach_type = bpf_program__get_expected_attach_type(prog);
10593         link_fd = bpf_link_create(prog_fd, target_fd, attach_type, &opts);
10594         if (link_fd < 0) {
10595                 link_fd = -errno;
10596                 free(link);
10597                 pr_warn("prog '%s': failed to attach to %s: %s\n",
10598                         prog->name, target_name,
10599                         libbpf_strerror_r(link_fd, errmsg, sizeof(errmsg)));
10600                 return libbpf_err_ptr(link_fd);
10601         }
10602         link->fd = link_fd;
10603         return link;
10604 }
10605
10606 struct bpf_link *
10607 bpf_program__attach_cgroup(struct bpf_program *prog, int cgroup_fd)
10608 {
10609         return bpf_program__attach_fd(prog, cgroup_fd, 0, "cgroup");
10610 }
10611
10612 struct bpf_link *
10613 bpf_program__attach_netns(struct bpf_program *prog, int netns_fd)
10614 {
10615         return bpf_program__attach_fd(prog, netns_fd, 0, "netns");
10616 }
10617
10618 struct bpf_link *bpf_program__attach_xdp(struct bpf_program *prog, int ifindex)
10619 {
10620         /* target_fd/target_ifindex use the same field in LINK_CREATE */
10621         return bpf_program__attach_fd(prog, ifindex, 0, "xdp");
10622 }
10623
10624 struct bpf_link *bpf_program__attach_freplace(struct bpf_program *prog,
10625                                               int target_fd,
10626                                               const char *attach_func_name)
10627 {
10628         int btf_id;
10629
10630         if (!!target_fd != !!attach_func_name) {
10631                 pr_warn("prog '%s': supply none or both of target_fd and attach_func_name\n",
10632                         prog->name);
10633                 return libbpf_err_ptr(-EINVAL);
10634         }
10635
10636         if (prog->type != BPF_PROG_TYPE_EXT) {
10637                 pr_warn("prog '%s': only BPF_PROG_TYPE_EXT can attach as freplace",
10638                         prog->name);
10639                 return libbpf_err_ptr(-EINVAL);
10640         }
10641
10642         if (target_fd) {
10643                 btf_id = libbpf_find_prog_btf_id(attach_func_name, target_fd);
10644                 if (btf_id < 0)
10645                         return libbpf_err_ptr(btf_id);
10646
10647                 return bpf_program__attach_fd(prog, target_fd, btf_id, "freplace");
10648         } else {
10649                 /* no target, so use raw_tracepoint_open for compatibility
10650                  * with old kernels
10651                  */
10652                 return bpf_program__attach_trace(prog);
10653         }
10654 }
10655
10656 struct bpf_link *
10657 bpf_program__attach_iter(struct bpf_program *prog,
10658                          const struct bpf_iter_attach_opts *opts)
10659 {
10660         DECLARE_LIBBPF_OPTS(bpf_link_create_opts, link_create_opts);
10661         char errmsg[STRERR_BUFSIZE];
10662         struct bpf_link *link;
10663         int prog_fd, link_fd;
10664         __u32 target_fd = 0;
10665
10666         if (!OPTS_VALID(opts, bpf_iter_attach_opts))
10667                 return libbpf_err_ptr(-EINVAL);
10668
10669         link_create_opts.iter_info = OPTS_GET(opts, link_info, (void *)0);
10670         link_create_opts.iter_info_len = OPTS_GET(opts, link_info_len, 0);
10671
10672         prog_fd = bpf_program__fd(prog);
10673         if (prog_fd < 0) {
10674                 pr_warn("prog '%s': can't attach before loaded\n", prog->name);
10675                 return libbpf_err_ptr(-EINVAL);
10676         }
10677
10678         link = calloc(1, sizeof(*link));
10679         if (!link)
10680                 return libbpf_err_ptr(-ENOMEM);
10681         link->detach = &bpf_link__detach_fd;
10682
10683         link_fd = bpf_link_create(prog_fd, target_fd, BPF_TRACE_ITER,
10684                                   &link_create_opts);
10685         if (link_fd < 0) {
10686                 link_fd = -errno;
10687                 free(link);
10688                 pr_warn("prog '%s': failed to attach to iterator: %s\n",
10689                         prog->name, libbpf_strerror_r(link_fd, errmsg, sizeof(errmsg)));
10690                 return libbpf_err_ptr(link_fd);
10691         }
10692         link->fd = link_fd;
10693         return link;
10694 }
10695
10696 static struct bpf_link *attach_iter(const struct bpf_sec_def *sec,
10697                                     struct bpf_program *prog)
10698 {
10699         return bpf_program__attach_iter(prog, NULL);
10700 }
10701
10702 struct bpf_link *bpf_program__attach(struct bpf_program *prog)
10703 {
10704         const struct bpf_sec_def *sec_def;
10705
10706         sec_def = find_sec_def(prog->sec_name);
10707         if (!sec_def || !sec_def->attach_fn)
10708                 return libbpf_err_ptr(-ESRCH);
10709
10710         return sec_def->attach_fn(sec_def, prog);
10711 }
10712
10713 static int bpf_link__detach_struct_ops(struct bpf_link *link)
10714 {
10715         __u32 zero = 0;
10716
10717         if (bpf_map_delete_elem(link->fd, &zero))
10718                 return -errno;
10719
10720         return 0;
10721 }
10722
10723 struct bpf_link *bpf_map__attach_struct_ops(struct bpf_map *map)
10724 {
10725         struct bpf_struct_ops *st_ops;
10726         struct bpf_link *link;
10727         __u32 i, zero = 0;
10728         int err;
10729
10730         if (!bpf_map__is_struct_ops(map) || map->fd == -1)
10731                 return libbpf_err_ptr(-EINVAL);
10732
10733         link = calloc(1, sizeof(*link));
10734         if (!link)
10735                 return libbpf_err_ptr(-EINVAL);
10736
10737         st_ops = map->st_ops;
10738         for (i = 0; i < btf_vlen(st_ops->type); i++) {
10739                 struct bpf_program *prog = st_ops->progs[i];
10740                 void *kern_data;
10741                 int prog_fd;
10742
10743                 if (!prog)
10744                         continue;
10745
10746                 prog_fd = bpf_program__fd(prog);
10747                 kern_data = st_ops->kern_vdata + st_ops->kern_func_off[i];
10748                 *(unsigned long *)kern_data = prog_fd;
10749         }
10750
10751         err = bpf_map_update_elem(map->fd, &zero, st_ops->kern_vdata, 0);
10752         if (err) {
10753                 err = -errno;
10754                 free(link);
10755                 return libbpf_err_ptr(err);
10756         }
10757
10758         link->detach = bpf_link__detach_struct_ops;
10759         link->fd = map->fd;
10760
10761         return link;
10762 }
10763
10764 enum bpf_perf_event_ret
10765 bpf_perf_event_read_simple(void *mmap_mem, size_t mmap_size, size_t page_size,
10766                            void **copy_mem, size_t *copy_size,
10767                            bpf_perf_event_print_t fn, void *private_data)
10768 {
10769         struct perf_event_mmap_page *header = mmap_mem;
10770         __u64 data_head = ring_buffer_read_head(header);
10771         __u64 data_tail = header->data_tail;
10772         void *base = ((__u8 *)header) + page_size;
10773         int ret = LIBBPF_PERF_EVENT_CONT;
10774         struct perf_event_header *ehdr;
10775         size_t ehdr_size;
10776
10777         while (data_head != data_tail) {
10778                 ehdr = base + (data_tail & (mmap_size - 1));
10779                 ehdr_size = ehdr->size;
10780
10781                 if (((void *)ehdr) + ehdr_size > base + mmap_size) {
10782                         void *copy_start = ehdr;
10783                         size_t len_first = base + mmap_size - copy_start;
10784                         size_t len_secnd = ehdr_size - len_first;
10785
10786                         if (*copy_size < ehdr_size) {
10787                                 free(*copy_mem);
10788                                 *copy_mem = malloc(ehdr_size);
10789                                 if (!*copy_mem) {
10790                                         *copy_size = 0;
10791                                         ret = LIBBPF_PERF_EVENT_ERROR;
10792                                         break;
10793                                 }
10794                                 *copy_size = ehdr_size;
10795                         }
10796
10797                         memcpy(*copy_mem, copy_start, len_first);
10798                         memcpy(*copy_mem + len_first, base, len_secnd);
10799                         ehdr = *copy_mem;
10800                 }
10801
10802                 ret = fn(ehdr, private_data);
10803                 data_tail += ehdr_size;
10804                 if (ret != LIBBPF_PERF_EVENT_CONT)
10805                         break;
10806         }
10807
10808         ring_buffer_write_tail(header, data_tail);
10809         return libbpf_err(ret);
10810 }
10811
10812 struct perf_buffer;
10813
10814 struct perf_buffer_params {
10815         struct perf_event_attr *attr;
10816         /* if event_cb is specified, it takes precendence */
10817         perf_buffer_event_fn event_cb;
10818         /* sample_cb and lost_cb are higher-level common-case callbacks */
10819         perf_buffer_sample_fn sample_cb;
10820         perf_buffer_lost_fn lost_cb;
10821         void *ctx;
10822         int cpu_cnt;
10823         int *cpus;
10824         int *map_keys;
10825 };
10826
10827 struct perf_cpu_buf {
10828         struct perf_buffer *pb;
10829         void *base; /* mmap()'ed memory */
10830         void *buf; /* for reconstructing segmented data */
10831         size_t buf_size;
10832         int fd;
10833         int cpu;
10834         int map_key;
10835 };
10836
10837 struct perf_buffer {
10838         perf_buffer_event_fn event_cb;
10839         perf_buffer_sample_fn sample_cb;
10840         perf_buffer_lost_fn lost_cb;
10841         void *ctx; /* passed into callbacks */
10842
10843         size_t page_size;
10844         size_t mmap_size;
10845         struct perf_cpu_buf **cpu_bufs;
10846         struct epoll_event *events;
10847         int cpu_cnt; /* number of allocated CPU buffers */
10848         int epoll_fd; /* perf event FD */
10849         int map_fd; /* BPF_MAP_TYPE_PERF_EVENT_ARRAY BPF map FD */
10850 };
10851
10852 static void perf_buffer__free_cpu_buf(struct perf_buffer *pb,
10853                                       struct perf_cpu_buf *cpu_buf)
10854 {
10855         if (!cpu_buf)
10856                 return;
10857         if (cpu_buf->base &&
10858             munmap(cpu_buf->base, pb->mmap_size + pb->page_size))
10859                 pr_warn("failed to munmap cpu_buf #%d\n", cpu_buf->cpu);
10860         if (cpu_buf->fd >= 0) {
10861                 ioctl(cpu_buf->fd, PERF_EVENT_IOC_DISABLE, 0);
10862                 close(cpu_buf->fd);
10863         }
10864         free(cpu_buf->buf);
10865         free(cpu_buf);
10866 }
10867
10868 void perf_buffer__free(struct perf_buffer *pb)
10869 {
10870         int i;
10871
10872         if (IS_ERR_OR_NULL(pb))
10873                 return;
10874         if (pb->cpu_bufs) {
10875                 for (i = 0; i < pb->cpu_cnt; i++) {
10876                         struct perf_cpu_buf *cpu_buf = pb->cpu_bufs[i];
10877
10878                         if (!cpu_buf)
10879                                 continue;
10880
10881                         bpf_map_delete_elem(pb->map_fd, &cpu_buf->map_key);
10882                         perf_buffer__free_cpu_buf(pb, cpu_buf);
10883                 }
10884                 free(pb->cpu_bufs);
10885         }
10886         if (pb->epoll_fd >= 0)
10887                 close(pb->epoll_fd);
10888         free(pb->events);
10889         free(pb);
10890 }
10891
10892 static struct perf_cpu_buf *
10893 perf_buffer__open_cpu_buf(struct perf_buffer *pb, struct perf_event_attr *attr,
10894                           int cpu, int map_key)
10895 {
10896         struct perf_cpu_buf *cpu_buf;
10897         char msg[STRERR_BUFSIZE];
10898         int err;
10899
10900         cpu_buf = calloc(1, sizeof(*cpu_buf));
10901         if (!cpu_buf)
10902                 return ERR_PTR(-ENOMEM);
10903
10904         cpu_buf->pb = pb;
10905         cpu_buf->cpu = cpu;
10906         cpu_buf->map_key = map_key;
10907
10908         cpu_buf->fd = syscall(__NR_perf_event_open, attr, -1 /* pid */, cpu,
10909                               -1, PERF_FLAG_FD_CLOEXEC);
10910         if (cpu_buf->fd < 0) {
10911                 err = -errno;
10912                 pr_warn("failed to open perf buffer event on cpu #%d: %s\n",
10913                         cpu, libbpf_strerror_r(err, msg, sizeof(msg)));
10914                 goto error;
10915         }
10916
10917         cpu_buf->base = mmap(NULL, pb->mmap_size + pb->page_size,
10918                              PROT_READ | PROT_WRITE, MAP_SHARED,
10919                              cpu_buf->fd, 0);
10920         if (cpu_buf->base == MAP_FAILED) {
10921                 cpu_buf->base = NULL;
10922                 err = -errno;
10923                 pr_warn("failed to mmap perf buffer on cpu #%d: %s\n",
10924                         cpu, libbpf_strerror_r(err, msg, sizeof(msg)));
10925                 goto error;
10926         }
10927
10928         if (ioctl(cpu_buf->fd, PERF_EVENT_IOC_ENABLE, 0) < 0) {
10929                 err = -errno;
10930                 pr_warn("failed to enable perf buffer event on cpu #%d: %s\n",
10931                         cpu, libbpf_strerror_r(err, msg, sizeof(msg)));
10932                 goto error;
10933         }
10934
10935         return cpu_buf;
10936
10937 error:
10938         perf_buffer__free_cpu_buf(pb, cpu_buf);
10939         return (struct perf_cpu_buf *)ERR_PTR(err);
10940 }
10941
10942 static struct perf_buffer *__perf_buffer__new(int map_fd, size_t page_cnt,
10943                                               struct perf_buffer_params *p);
10944
10945 struct perf_buffer *perf_buffer__new(int map_fd, size_t page_cnt,
10946                                      const struct perf_buffer_opts *opts)
10947 {
10948         struct perf_buffer_params p = {};
10949         struct perf_event_attr attr = { 0, };
10950
10951         attr.config = PERF_COUNT_SW_BPF_OUTPUT;
10952         attr.type = PERF_TYPE_SOFTWARE;
10953         attr.sample_type = PERF_SAMPLE_RAW;
10954         attr.sample_period = 1;
10955         attr.wakeup_events = 1;
10956
10957         p.attr = &attr;
10958         p.sample_cb = opts ? opts->sample_cb : NULL;
10959         p.lost_cb = opts ? opts->lost_cb : NULL;
10960         p.ctx = opts ? opts->ctx : NULL;
10961
10962         return libbpf_ptr(__perf_buffer__new(map_fd, page_cnt, &p));
10963 }
10964
10965 struct perf_buffer *
10966 perf_buffer__new_raw(int map_fd, size_t page_cnt,
10967                      const struct perf_buffer_raw_opts *opts)
10968 {
10969         struct perf_buffer_params p = {};
10970
10971         p.attr = opts->attr;
10972         p.event_cb = opts->event_cb;
10973         p.ctx = opts->ctx;
10974         p.cpu_cnt = opts->cpu_cnt;
10975         p.cpus = opts->cpus;
10976         p.map_keys = opts->map_keys;
10977
10978         return libbpf_ptr(__perf_buffer__new(map_fd, page_cnt, &p));
10979 }
10980
10981 static struct perf_buffer *__perf_buffer__new(int map_fd, size_t page_cnt,
10982                                               struct perf_buffer_params *p)
10983 {
10984         const char *online_cpus_file = "/sys/devices/system/cpu/online";
10985         struct bpf_map_info map;
10986         char msg[STRERR_BUFSIZE];
10987         struct perf_buffer *pb;
10988         bool *online = NULL;
10989         __u32 map_info_len;
10990         int err, i, j, n;
10991
10992         if (page_cnt & (page_cnt - 1)) {
10993                 pr_warn("page count should be power of two, but is %zu\n",
10994                         page_cnt);
10995                 return ERR_PTR(-EINVAL);
10996         }
10997
10998         /* best-effort sanity checks */
10999         memset(&map, 0, sizeof(map));
11000         map_info_len = sizeof(map);
11001         err = bpf_obj_get_info_by_fd(map_fd, &map, &map_info_len);
11002         if (err) {
11003                 err = -errno;
11004                 /* if BPF_OBJ_GET_INFO_BY_FD is supported, will return
11005                  * -EBADFD, -EFAULT, or -E2BIG on real error
11006                  */
11007                 if (err != -EINVAL) {
11008                         pr_warn("failed to get map info for map FD %d: %s\n",
11009                                 map_fd, libbpf_strerror_r(err, msg, sizeof(msg)));
11010                         return ERR_PTR(err);
11011                 }
11012                 pr_debug("failed to get map info for FD %d; API not supported? Ignoring...\n",
11013                          map_fd);
11014         } else {
11015                 if (map.type != BPF_MAP_TYPE_PERF_EVENT_ARRAY) {
11016                         pr_warn("map '%s' should be BPF_MAP_TYPE_PERF_EVENT_ARRAY\n",
11017                                 map.name);
11018                         return ERR_PTR(-EINVAL);
11019                 }
11020         }
11021
11022         pb = calloc(1, sizeof(*pb));
11023         if (!pb)
11024                 return ERR_PTR(-ENOMEM);
11025
11026         pb->event_cb = p->event_cb;
11027         pb->sample_cb = p->sample_cb;
11028         pb->lost_cb = p->lost_cb;
11029         pb->ctx = p->ctx;
11030
11031         pb->page_size = getpagesize();
11032         pb->mmap_size = pb->page_size * page_cnt;
11033         pb->map_fd = map_fd;
11034
11035         pb->epoll_fd = epoll_create1(EPOLL_CLOEXEC);
11036         if (pb->epoll_fd < 0) {
11037                 err = -errno;
11038                 pr_warn("failed to create epoll instance: %s\n",
11039                         libbpf_strerror_r(err, msg, sizeof(msg)));
11040                 goto error;
11041         }
11042
11043         if (p->cpu_cnt > 0) {
11044                 pb->cpu_cnt = p->cpu_cnt;
11045         } else {
11046                 pb->cpu_cnt = libbpf_num_possible_cpus();
11047                 if (pb->cpu_cnt < 0) {
11048                         err = pb->cpu_cnt;
11049                         goto error;
11050                 }
11051                 if (map.max_entries && map.max_entries < pb->cpu_cnt)
11052                         pb->cpu_cnt = map.max_entries;
11053         }
11054
11055         pb->events = calloc(pb->cpu_cnt, sizeof(*pb->events));
11056         if (!pb->events) {
11057                 err = -ENOMEM;
11058                 pr_warn("failed to allocate events: out of memory\n");
11059                 goto error;
11060         }
11061         pb->cpu_bufs = calloc(pb->cpu_cnt, sizeof(*pb->cpu_bufs));
11062         if (!pb->cpu_bufs) {
11063                 err = -ENOMEM;
11064                 pr_warn("failed to allocate buffers: out of memory\n");
11065                 goto error;
11066         }
11067
11068         err = parse_cpu_mask_file(online_cpus_file, &online, &n);
11069         if (err) {
11070                 pr_warn("failed to get online CPU mask: %d\n", err);
11071                 goto error;
11072         }
11073
11074         for (i = 0, j = 0; i < pb->cpu_cnt; i++) {
11075                 struct perf_cpu_buf *cpu_buf;
11076                 int cpu, map_key;
11077
11078                 cpu = p->cpu_cnt > 0 ? p->cpus[i] : i;
11079                 map_key = p->cpu_cnt > 0 ? p->map_keys[i] : i;
11080
11081                 /* in case user didn't explicitly requested particular CPUs to
11082                  * be attached to, skip offline/not present CPUs
11083                  */
11084                 if (p->cpu_cnt <= 0 && (cpu >= n || !online[cpu]))
11085                         continue;
11086
11087                 cpu_buf = perf_buffer__open_cpu_buf(pb, p->attr, cpu, map_key);
11088                 if (IS_ERR(cpu_buf)) {
11089                         err = PTR_ERR(cpu_buf);
11090                         goto error;
11091                 }
11092
11093                 pb->cpu_bufs[j] = cpu_buf;
11094
11095                 err = bpf_map_update_elem(pb->map_fd, &map_key,
11096                                           &cpu_buf->fd, 0);
11097                 if (err) {
11098                         err = -errno;
11099                         pr_warn("failed to set cpu #%d, key %d -> perf FD %d: %s\n",
11100                                 cpu, map_key, cpu_buf->fd,
11101                                 libbpf_strerror_r(err, msg, sizeof(msg)));
11102                         goto error;
11103                 }
11104
11105                 pb->events[j].events = EPOLLIN;
11106                 pb->events[j].data.ptr = cpu_buf;
11107                 if (epoll_ctl(pb->epoll_fd, EPOLL_CTL_ADD, cpu_buf->fd,
11108                               &pb->events[j]) < 0) {
11109                         err = -errno;
11110                         pr_warn("failed to epoll_ctl cpu #%d perf FD %d: %s\n",
11111                                 cpu, cpu_buf->fd,
11112                                 libbpf_strerror_r(err, msg, sizeof(msg)));
11113                         goto error;
11114                 }
11115                 j++;
11116         }
11117         pb->cpu_cnt = j;
11118         free(online);
11119
11120         return pb;
11121
11122 error:
11123         free(online);
11124         if (pb)
11125                 perf_buffer__free(pb);
11126         return ERR_PTR(err);
11127 }
11128
11129 struct perf_sample_raw {
11130         struct perf_event_header header;
11131         uint32_t size;
11132         char data[];
11133 };
11134
11135 struct perf_sample_lost {
11136         struct perf_event_header header;
11137         uint64_t id;
11138         uint64_t lost;
11139         uint64_t sample_id;
11140 };
11141
11142 static enum bpf_perf_event_ret
11143 perf_buffer__process_record(struct perf_event_header *e, void *ctx)
11144 {
11145         struct perf_cpu_buf *cpu_buf = ctx;
11146         struct perf_buffer *pb = cpu_buf->pb;
11147         void *data = e;
11148
11149         /* user wants full control over parsing perf event */
11150         if (pb->event_cb)
11151                 return pb->event_cb(pb->ctx, cpu_buf->cpu, e);
11152
11153         switch (e->type) {
11154         case PERF_RECORD_SAMPLE: {
11155                 struct perf_sample_raw *s = data;
11156
11157                 if (pb->sample_cb)
11158                         pb->sample_cb(pb->ctx, cpu_buf->cpu, s->data, s->size);
11159                 break;
11160         }
11161         case PERF_RECORD_LOST: {
11162                 struct perf_sample_lost *s = data;
11163
11164                 if (pb->lost_cb)
11165                         pb->lost_cb(pb->ctx, cpu_buf->cpu, s->lost);
11166                 break;
11167         }
11168         default:
11169                 pr_warn("unknown perf sample type %d\n", e->type);
11170                 return LIBBPF_PERF_EVENT_ERROR;
11171         }
11172         return LIBBPF_PERF_EVENT_CONT;
11173 }
11174
11175 static int perf_buffer__process_records(struct perf_buffer *pb,
11176                                         struct perf_cpu_buf *cpu_buf)
11177 {
11178         enum bpf_perf_event_ret ret;
11179
11180         ret = bpf_perf_event_read_simple(cpu_buf->base, pb->mmap_size,
11181                                          pb->page_size, &cpu_buf->buf,
11182                                          &cpu_buf->buf_size,
11183                                          perf_buffer__process_record, cpu_buf);
11184         if (ret != LIBBPF_PERF_EVENT_CONT)
11185                 return ret;
11186         return 0;
11187 }
11188
11189 int perf_buffer__epoll_fd(const struct perf_buffer *pb)
11190 {
11191         return pb->epoll_fd;
11192 }
11193
11194 int perf_buffer__poll(struct perf_buffer *pb, int timeout_ms)
11195 {
11196         int i, cnt, err;
11197
11198         cnt = epoll_wait(pb->epoll_fd, pb->events, pb->cpu_cnt, timeout_ms);
11199         if (cnt < 0)
11200                 return libbpf_err_errno(cnt);
11201
11202         for (i = 0; i < cnt; i++) {
11203                 struct perf_cpu_buf *cpu_buf = pb->events[i].data.ptr;
11204
11205                 err = perf_buffer__process_records(pb, cpu_buf);
11206                 if (err) {
11207                         pr_warn("error while processing records: %d\n", err);
11208                         return libbpf_err(err);
11209                 }
11210         }
11211         return cnt;
11212 }
11213
11214 /* Return number of PERF_EVENT_ARRAY map slots set up by this perf_buffer
11215  * manager.
11216  */
11217 size_t perf_buffer__buffer_cnt(const struct perf_buffer *pb)
11218 {
11219         return pb->cpu_cnt;
11220 }
11221
11222 /*
11223  * Return perf_event FD of a ring buffer in *buf_idx* slot of
11224  * PERF_EVENT_ARRAY BPF map. This FD can be polled for new data using
11225  * select()/poll()/epoll() Linux syscalls.
11226  */
11227 int perf_buffer__buffer_fd(const struct perf_buffer *pb, size_t buf_idx)
11228 {
11229         struct perf_cpu_buf *cpu_buf;
11230
11231         if (buf_idx >= pb->cpu_cnt)
11232                 return libbpf_err(-EINVAL);
11233
11234         cpu_buf = pb->cpu_bufs[buf_idx];
11235         if (!cpu_buf)
11236                 return libbpf_err(-ENOENT);
11237
11238         return cpu_buf->fd;
11239 }
11240
11241 /*
11242  * Consume data from perf ring buffer corresponding to slot *buf_idx* in
11243  * PERF_EVENT_ARRAY BPF map without waiting/polling. If there is no data to
11244  * consume, do nothing and return success.
11245  * Returns:
11246  *   - 0 on success;
11247  *   - <0 on failure.
11248  */
11249 int perf_buffer__consume_buffer(struct perf_buffer *pb, size_t buf_idx)
11250 {
11251         struct perf_cpu_buf *cpu_buf;
11252
11253         if (buf_idx >= pb->cpu_cnt)
11254                 return libbpf_err(-EINVAL);
11255
11256         cpu_buf = pb->cpu_bufs[buf_idx];
11257         if (!cpu_buf)
11258                 return libbpf_err(-ENOENT);
11259
11260         return perf_buffer__process_records(pb, cpu_buf);
11261 }
11262
11263 int perf_buffer__consume(struct perf_buffer *pb)
11264 {
11265         int i, err;
11266
11267         for (i = 0; i < pb->cpu_cnt; i++) {
11268                 struct perf_cpu_buf *cpu_buf = pb->cpu_bufs[i];
11269
11270                 if (!cpu_buf)
11271                         continue;
11272
11273                 err = perf_buffer__process_records(pb, cpu_buf);
11274                 if (err) {
11275                         pr_warn("perf_buffer: failed to process records in buffer #%d: %d\n", i, err);
11276                         return libbpf_err(err);
11277                 }
11278         }
11279         return 0;
11280 }
11281
11282 struct bpf_prog_info_array_desc {
11283         int     array_offset;   /* e.g. offset of jited_prog_insns */
11284         int     count_offset;   /* e.g. offset of jited_prog_len */
11285         int     size_offset;    /* > 0: offset of rec size,
11286                                  * < 0: fix size of -size_offset
11287                                  */
11288 };
11289
11290 static struct bpf_prog_info_array_desc bpf_prog_info_array_desc[] = {
11291         [BPF_PROG_INFO_JITED_INSNS] = {
11292                 offsetof(struct bpf_prog_info, jited_prog_insns),
11293                 offsetof(struct bpf_prog_info, jited_prog_len),
11294                 -1,
11295         },
11296         [BPF_PROG_INFO_XLATED_INSNS] = {
11297                 offsetof(struct bpf_prog_info, xlated_prog_insns),
11298                 offsetof(struct bpf_prog_info, xlated_prog_len),
11299                 -1,
11300         },
11301         [BPF_PROG_INFO_MAP_IDS] = {
11302                 offsetof(struct bpf_prog_info, map_ids),
11303                 offsetof(struct bpf_prog_info, nr_map_ids),
11304                 -(int)sizeof(__u32),
11305         },
11306         [BPF_PROG_INFO_JITED_KSYMS] = {
11307                 offsetof(struct bpf_prog_info, jited_ksyms),
11308                 offsetof(struct bpf_prog_info, nr_jited_ksyms),
11309                 -(int)sizeof(__u64),
11310         },
11311         [BPF_PROG_INFO_JITED_FUNC_LENS] = {
11312                 offsetof(struct bpf_prog_info, jited_func_lens),
11313                 offsetof(struct bpf_prog_info, nr_jited_func_lens),
11314                 -(int)sizeof(__u32),
11315         },
11316         [BPF_PROG_INFO_FUNC_INFO] = {
11317                 offsetof(struct bpf_prog_info, func_info),
11318                 offsetof(struct bpf_prog_info, nr_func_info),
11319                 offsetof(struct bpf_prog_info, func_info_rec_size),
11320         },
11321         [BPF_PROG_INFO_LINE_INFO] = {
11322                 offsetof(struct bpf_prog_info, line_info),
11323                 offsetof(struct bpf_prog_info, nr_line_info),
11324                 offsetof(struct bpf_prog_info, line_info_rec_size),
11325         },
11326         [BPF_PROG_INFO_JITED_LINE_INFO] = {
11327                 offsetof(struct bpf_prog_info, jited_line_info),
11328                 offsetof(struct bpf_prog_info, nr_jited_line_info),
11329                 offsetof(struct bpf_prog_info, jited_line_info_rec_size),
11330         },
11331         [BPF_PROG_INFO_PROG_TAGS] = {
11332                 offsetof(struct bpf_prog_info, prog_tags),
11333                 offsetof(struct bpf_prog_info, nr_prog_tags),
11334                 -(int)sizeof(__u8) * BPF_TAG_SIZE,
11335         },
11336
11337 };
11338
11339 static __u32 bpf_prog_info_read_offset_u32(struct bpf_prog_info *info,
11340                                            int offset)
11341 {
11342         __u32 *array = (__u32 *)info;
11343
11344         if (offset >= 0)
11345                 return array[offset / sizeof(__u32)];
11346         return -(int)offset;
11347 }
11348
11349 static __u64 bpf_prog_info_read_offset_u64(struct bpf_prog_info *info,
11350                                            int offset)
11351 {
11352         __u64 *array = (__u64 *)info;
11353
11354         if (offset >= 0)
11355                 return array[offset / sizeof(__u64)];
11356         return -(int)offset;
11357 }
11358
11359 static void bpf_prog_info_set_offset_u32(struct bpf_prog_info *info, int offset,
11360                                          __u32 val)
11361 {
11362         __u32 *array = (__u32 *)info;
11363
11364         if (offset >= 0)
11365                 array[offset / sizeof(__u32)] = val;
11366 }
11367
11368 static void bpf_prog_info_set_offset_u64(struct bpf_prog_info *info, int offset,
11369                                          __u64 val)
11370 {
11371         __u64 *array = (__u64 *)info;
11372
11373         if (offset >= 0)
11374                 array[offset / sizeof(__u64)] = val;
11375 }
11376
11377 struct bpf_prog_info_linear *
11378 bpf_program__get_prog_info_linear(int fd, __u64 arrays)
11379 {
11380         struct bpf_prog_info_linear *info_linear;
11381         struct bpf_prog_info info = {};
11382         __u32 info_len = sizeof(info);
11383         __u32 data_len = 0;
11384         int i, err;
11385         void *ptr;
11386
11387         if (arrays >> BPF_PROG_INFO_LAST_ARRAY)
11388                 return libbpf_err_ptr(-EINVAL);
11389
11390         /* step 1: get array dimensions */
11391         err = bpf_obj_get_info_by_fd(fd, &info, &info_len);
11392         if (err) {
11393                 pr_debug("can't get prog info: %s", strerror(errno));
11394                 return libbpf_err_ptr(-EFAULT);
11395         }
11396
11397         /* step 2: calculate total size of all arrays */
11398         for (i = BPF_PROG_INFO_FIRST_ARRAY; i < BPF_PROG_INFO_LAST_ARRAY; ++i) {
11399                 bool include_array = (arrays & (1UL << i)) > 0;
11400                 struct bpf_prog_info_array_desc *desc;
11401                 __u32 count, size;
11402
11403                 desc = bpf_prog_info_array_desc + i;
11404
11405                 /* kernel is too old to support this field */
11406                 if (info_len < desc->array_offset + sizeof(__u32) ||
11407                     info_len < desc->count_offset + sizeof(__u32) ||
11408                     (desc->size_offset > 0 && info_len < desc->size_offset))
11409                         include_array = false;
11410
11411                 if (!include_array) {
11412                         arrays &= ~(1UL << i);  /* clear the bit */
11413                         continue;
11414                 }
11415
11416                 count = bpf_prog_info_read_offset_u32(&info, desc->count_offset);
11417                 size  = bpf_prog_info_read_offset_u32(&info, desc->size_offset);
11418
11419                 data_len += count * size;
11420         }
11421
11422         /* step 3: allocate continuous memory */
11423         data_len = roundup(data_len, sizeof(__u64));
11424         info_linear = malloc(sizeof(struct bpf_prog_info_linear) + data_len);
11425         if (!info_linear)
11426                 return libbpf_err_ptr(-ENOMEM);
11427
11428         /* step 4: fill data to info_linear->info */
11429         info_linear->arrays = arrays;
11430         memset(&info_linear->info, 0, sizeof(info));
11431         ptr = info_linear->data;
11432
11433         for (i = BPF_PROG_INFO_FIRST_ARRAY; i < BPF_PROG_INFO_LAST_ARRAY; ++i) {
11434                 struct bpf_prog_info_array_desc *desc;
11435                 __u32 count, size;
11436
11437                 if ((arrays & (1UL << i)) == 0)
11438                         continue;
11439
11440                 desc  = bpf_prog_info_array_desc + i;
11441                 count = bpf_prog_info_read_offset_u32(&info, desc->count_offset);
11442                 size  = bpf_prog_info_read_offset_u32(&info, desc->size_offset);
11443                 bpf_prog_info_set_offset_u32(&info_linear->info,
11444                                              desc->count_offset, count);
11445                 bpf_prog_info_set_offset_u32(&info_linear->info,
11446                                              desc->size_offset, size);
11447                 bpf_prog_info_set_offset_u64(&info_linear->info,
11448                                              desc->array_offset,
11449                                              ptr_to_u64(ptr));
11450                 ptr += count * size;
11451         }
11452
11453         /* step 5: call syscall again to get required arrays */
11454         err = bpf_obj_get_info_by_fd(fd, &info_linear->info, &info_len);
11455         if (err) {
11456                 pr_debug("can't get prog info: %s", strerror(errno));
11457                 free(info_linear);
11458                 return libbpf_err_ptr(-EFAULT);
11459         }
11460
11461         /* step 6: verify the data */
11462         for (i = BPF_PROG_INFO_FIRST_ARRAY; i < BPF_PROG_INFO_LAST_ARRAY; ++i) {
11463                 struct bpf_prog_info_array_desc *desc;
11464                 __u32 v1, v2;
11465
11466                 if ((arrays & (1UL << i)) == 0)
11467                         continue;
11468
11469                 desc = bpf_prog_info_array_desc + i;
11470                 v1 = bpf_prog_info_read_offset_u32(&info, desc->count_offset);
11471                 v2 = bpf_prog_info_read_offset_u32(&info_linear->info,
11472                                                    desc->count_offset);
11473                 if (v1 != v2)
11474                         pr_warn("%s: mismatch in element count\n", __func__);
11475
11476                 v1 = bpf_prog_info_read_offset_u32(&info, desc->size_offset);
11477                 v2 = bpf_prog_info_read_offset_u32(&info_linear->info,
11478                                                    desc->size_offset);
11479                 if (v1 != v2)
11480                         pr_warn("%s: mismatch in rec size\n", __func__);
11481         }
11482
11483         /* step 7: update info_len and data_len */
11484         info_linear->info_len = sizeof(struct bpf_prog_info);
11485         info_linear->data_len = data_len;
11486
11487         return info_linear;
11488 }
11489
11490 void bpf_program__bpil_addr_to_offs(struct bpf_prog_info_linear *info_linear)
11491 {
11492         int i;
11493
11494         for (i = BPF_PROG_INFO_FIRST_ARRAY; i < BPF_PROG_INFO_LAST_ARRAY; ++i) {
11495                 struct bpf_prog_info_array_desc *desc;
11496                 __u64 addr, offs;
11497
11498                 if ((info_linear->arrays & (1UL << i)) == 0)
11499                         continue;
11500
11501                 desc = bpf_prog_info_array_desc + i;
11502                 addr = bpf_prog_info_read_offset_u64(&info_linear->info,
11503                                                      desc->array_offset);
11504                 offs = addr - ptr_to_u64(info_linear->data);
11505                 bpf_prog_info_set_offset_u64(&info_linear->info,
11506                                              desc->array_offset, offs);
11507         }
11508 }
11509
11510 void bpf_program__bpil_offs_to_addr(struct bpf_prog_info_linear *info_linear)
11511 {
11512         int i;
11513
11514         for (i = BPF_PROG_INFO_FIRST_ARRAY; i < BPF_PROG_INFO_LAST_ARRAY; ++i) {
11515                 struct bpf_prog_info_array_desc *desc;
11516                 __u64 addr, offs;
11517
11518                 if ((info_linear->arrays & (1UL << i)) == 0)
11519                         continue;
11520
11521                 desc = bpf_prog_info_array_desc + i;
11522                 offs = bpf_prog_info_read_offset_u64(&info_linear->info,
11523                                                      desc->array_offset);
11524                 addr = offs + ptr_to_u64(info_linear->data);
11525                 bpf_prog_info_set_offset_u64(&info_linear->info,
11526                                              desc->array_offset, addr);
11527         }
11528 }
11529
11530 int bpf_program__set_attach_target(struct bpf_program *prog,
11531                                    int attach_prog_fd,
11532                                    const char *attach_func_name)
11533 {
11534         int btf_obj_fd = 0, btf_id = 0, err;
11535
11536         if (!prog || attach_prog_fd < 0 || !attach_func_name)
11537                 return libbpf_err(-EINVAL);
11538
11539         if (prog->obj->loaded)
11540                 return libbpf_err(-EINVAL);
11541
11542         if (attach_prog_fd) {
11543                 btf_id = libbpf_find_prog_btf_id(attach_func_name,
11544                                                  attach_prog_fd);
11545                 if (btf_id < 0)
11546                         return libbpf_err(btf_id);
11547         } else {
11548                 /* load btf_vmlinux, if not yet */
11549                 err = bpf_object__load_vmlinux_btf(prog->obj, true);
11550                 if (err)
11551                         return libbpf_err(err);
11552                 err = find_kernel_btf_id(prog->obj, attach_func_name,
11553                                          prog->expected_attach_type,
11554                                          &btf_obj_fd, &btf_id);
11555                 if (err)
11556                         return libbpf_err(err);
11557         }
11558
11559         prog->attach_btf_id = btf_id;
11560         prog->attach_btf_obj_fd = btf_obj_fd;
11561         prog->attach_prog_fd = attach_prog_fd;
11562         return 0;
11563 }
11564
11565 int parse_cpu_mask_str(const char *s, bool **mask, int *mask_sz)
11566 {
11567         int err = 0, n, len, start, end = -1;
11568         bool *tmp;
11569
11570         *mask = NULL;
11571         *mask_sz = 0;
11572
11573         /* Each sub string separated by ',' has format \d+-\d+ or \d+ */
11574         while (*s) {
11575                 if (*s == ',' || *s == '\n') {
11576                         s++;
11577                         continue;
11578                 }
11579                 n = sscanf(s, "%d%n-%d%n", &start, &len, &end, &len);
11580                 if (n <= 0 || n > 2) {
11581                         pr_warn("Failed to get CPU range %s: %d\n", s, n);
11582                         err = -EINVAL;
11583                         goto cleanup;
11584                 } else if (n == 1) {
11585                         end = start;
11586                 }
11587                 if (start < 0 || start > end) {
11588                         pr_warn("Invalid CPU range [%d,%d] in %s\n",
11589                                 start, end, s);
11590                         err = -EINVAL;
11591                         goto cleanup;
11592                 }
11593                 tmp = realloc(*mask, end + 1);
11594                 if (!tmp) {
11595                         err = -ENOMEM;
11596                         goto cleanup;
11597                 }
11598                 *mask = tmp;
11599                 memset(tmp + *mask_sz, 0, start - *mask_sz);
11600                 memset(tmp + start, 1, end - start + 1);
11601                 *mask_sz = end + 1;
11602                 s += len;
11603         }
11604         if (!*mask_sz) {
11605                 pr_warn("Empty CPU range\n");
11606                 return -EINVAL;
11607         }
11608         return 0;
11609 cleanup:
11610         free(*mask);
11611         *mask = NULL;
11612         return err;
11613 }
11614
11615 int parse_cpu_mask_file(const char *fcpu, bool **mask, int *mask_sz)
11616 {
11617         int fd, err = 0, len;
11618         char buf[128];
11619
11620         fd = open(fcpu, O_RDONLY);
11621         if (fd < 0) {
11622                 err = -errno;
11623                 pr_warn("Failed to open cpu mask file %s: %d\n", fcpu, err);
11624                 return err;
11625         }
11626         len = read(fd, buf, sizeof(buf));
11627         close(fd);
11628         if (len <= 0) {
11629                 err = len ? -errno : -EINVAL;
11630                 pr_warn("Failed to read cpu mask from %s: %d\n", fcpu, err);
11631                 return err;
11632         }
11633         if (len >= sizeof(buf)) {
11634                 pr_warn("CPU mask is too big in file %s\n", fcpu);
11635                 return -E2BIG;
11636         }
11637         buf[len] = '\0';
11638
11639         return parse_cpu_mask_str(buf, mask, mask_sz);
11640 }
11641
11642 int libbpf_num_possible_cpus(void)
11643 {
11644         static const char *fcpu = "/sys/devices/system/cpu/possible";
11645         static int cpus;
11646         int err, n, i, tmp_cpus;
11647         bool *mask;
11648
11649         tmp_cpus = READ_ONCE(cpus);
11650         if (tmp_cpus > 0)
11651                 return tmp_cpus;
11652
11653         err = parse_cpu_mask_file(fcpu, &mask, &n);
11654         if (err)
11655                 return libbpf_err(err);
11656
11657         tmp_cpus = 0;
11658         for (i = 0; i < n; i++) {
11659                 if (mask[i])
11660                         tmp_cpus++;
11661         }
11662         free(mask);
11663
11664         WRITE_ONCE(cpus, tmp_cpus);
11665         return tmp_cpus;
11666 }
11667
11668 int bpf_object__open_skeleton(struct bpf_object_skeleton *s,
11669                               const struct bpf_object_open_opts *opts)
11670 {
11671         DECLARE_LIBBPF_OPTS(bpf_object_open_opts, skel_opts,
11672                 .object_name = s->name,
11673         );
11674         struct bpf_object *obj;
11675         int i, err;
11676
11677         /* Attempt to preserve opts->object_name, unless overriden by user
11678          * explicitly. Overwriting object name for skeletons is discouraged,
11679          * as it breaks global data maps, because they contain object name
11680          * prefix as their own map name prefix. When skeleton is generated,
11681          * bpftool is making an assumption that this name will stay the same.
11682          */
11683         if (opts) {
11684                 memcpy(&skel_opts, opts, sizeof(*opts));
11685                 if (!opts->object_name)
11686                         skel_opts.object_name = s->name;
11687         }
11688
11689         obj = bpf_object__open_mem(s->data, s->data_sz, &skel_opts);
11690         err = libbpf_get_error(obj);
11691         if (err) {
11692                 pr_warn("failed to initialize skeleton BPF object '%s': %d\n",
11693                         s->name, err);
11694                 return libbpf_err(err);
11695         }
11696
11697         *s->obj = obj;
11698
11699         for (i = 0; i < s->map_cnt; i++) {
11700                 struct bpf_map **map = s->maps[i].map;
11701                 const char *name = s->maps[i].name;
11702                 void **mmaped = s->maps[i].mmaped;
11703
11704                 *map = bpf_object__find_map_by_name(obj, name);
11705                 if (!*map) {
11706                         pr_warn("failed to find skeleton map '%s'\n", name);
11707                         return libbpf_err(-ESRCH);
11708                 }
11709
11710                 /* externs shouldn't be pre-setup from user code */
11711                 if (mmaped && (*map)->libbpf_type != LIBBPF_MAP_KCONFIG)
11712                         *mmaped = (*map)->mmaped;
11713         }
11714
11715         for (i = 0; i < s->prog_cnt; i++) {
11716                 struct bpf_program **prog = s->progs[i].prog;
11717                 const char *name = s->progs[i].name;
11718
11719                 *prog = bpf_object__find_program_by_name(obj, name);
11720                 if (!*prog) {
11721                         pr_warn("failed to find skeleton program '%s'\n", name);
11722                         return libbpf_err(-ESRCH);
11723                 }
11724         }
11725
11726         return 0;
11727 }
11728
11729 int bpf_object__load_skeleton(struct bpf_object_skeleton *s)
11730 {
11731         int i, err;
11732
11733         err = bpf_object__load(*s->obj);
11734         if (err) {
11735                 pr_warn("failed to load BPF skeleton '%s': %d\n", s->name, err);
11736                 return libbpf_err(err);
11737         }
11738
11739         for (i = 0; i < s->map_cnt; i++) {
11740                 struct bpf_map *map = *s->maps[i].map;
11741                 size_t mmap_sz = bpf_map_mmap_sz(map);
11742                 int prot, map_fd = bpf_map__fd(map);
11743                 void **mmaped = s->maps[i].mmaped;
11744
11745                 if (!mmaped)
11746                         continue;
11747
11748                 if (!(map->def.map_flags & BPF_F_MMAPABLE)) {
11749                         *mmaped = NULL;
11750                         continue;
11751                 }
11752
11753                 if (map->def.map_flags & BPF_F_RDONLY_PROG)
11754                         prot = PROT_READ;
11755                 else
11756                         prot = PROT_READ | PROT_WRITE;
11757
11758                 /* Remap anonymous mmap()-ed "map initialization image" as
11759                  * a BPF map-backed mmap()-ed memory, but preserving the same
11760                  * memory address. This will cause kernel to change process'
11761                  * page table to point to a different piece of kernel memory,
11762                  * but from userspace point of view memory address (and its
11763                  * contents, being identical at this point) will stay the
11764                  * same. This mapping will be released by bpf_object__close()
11765                  * as per normal clean up procedure, so we don't need to worry
11766                  * about it from skeleton's clean up perspective.
11767                  */
11768                 *mmaped = mmap(map->mmaped, mmap_sz, prot,
11769                                 MAP_SHARED | MAP_FIXED, map_fd, 0);
11770                 if (*mmaped == MAP_FAILED) {
11771                         err = -errno;
11772                         *mmaped = NULL;
11773                         pr_warn("failed to re-mmap() map '%s': %d\n",
11774                                  bpf_map__name(map), err);
11775                         return libbpf_err(err);
11776                 }
11777         }
11778
11779         return 0;
11780 }
11781
11782 int bpf_object__attach_skeleton(struct bpf_object_skeleton *s)
11783 {
11784         int i, err;
11785
11786         for (i = 0; i < s->prog_cnt; i++) {
11787                 struct bpf_program *prog = *s->progs[i].prog;
11788                 struct bpf_link **link = s->progs[i].link;
11789                 const struct bpf_sec_def *sec_def;
11790
11791                 if (!prog->load)
11792                         continue;
11793
11794                 sec_def = find_sec_def(prog->sec_name);
11795                 if (!sec_def || !sec_def->attach_fn)
11796                         continue;
11797
11798                 *link = sec_def->attach_fn(sec_def, prog);
11799                 err = libbpf_get_error(*link);
11800                 if (err) {
11801                         pr_warn("failed to auto-attach program '%s': %d\n",
11802                                 bpf_program__name(prog), err);
11803                         return libbpf_err(err);
11804                 }
11805         }
11806
11807         return 0;
11808 }
11809
11810 void bpf_object__detach_skeleton(struct bpf_object_skeleton *s)
11811 {
11812         int i;
11813
11814         for (i = 0; i < s->prog_cnt; i++) {
11815                 struct bpf_link **link = s->progs[i].link;
11816
11817                 bpf_link__destroy(*link);
11818                 *link = NULL;
11819         }
11820 }
11821
11822 void bpf_object__destroy_skeleton(struct bpf_object_skeleton *s)
11823 {
11824         if (s->progs)
11825                 bpf_object__detach_skeleton(s);
11826         if (s->obj)
11827                 bpf_object__close(*s->obj);
11828         free(s->maps);
11829         free(s->progs);
11830         free(s);
11831 }