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 <asm/unistd.h>
  28 #include <linux/err.h>
  29 #include <linux/kernel.h>
  30 #include <linux/bpf.h>
  31 #include <linux/btf.h>
  32 #include <linux/filter.h>
  33 #include <linux/list.h>
  34 #include <linux/limits.h>
  35 #include <linux/perf_event.h>
  36 #include <linux/ring_buffer.h>
  37 #include <linux/version.h>
  38 #include <sys/epoll.h>
  39 #include <sys/ioctl.h>
  40 #include <sys/mman.h>
  41 #include <sys/stat.h>
  42 #include <sys/types.h>
  43 #include <sys/vfs.h>
  44 #include <sys/utsname.h>
  45 #include <sys/resource.h>
  46 #include <tools/libc_compat.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
  58 /* make sure libbpf doesn't use kernel-only integer typedefs */
  59 #pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64
  60
  61 #ifndef EM_BPF
  62 #define EM_BPF 247
  63 #endif
  64
  65 #ifndef BPF_FS_MAGIC
  66 #define BPF_FS_MAGIC            0xcafe4a11
  67 #endif
  68
  69 /* vsprintf() in __base_pr() uses nonliteral format string. It may break
  70  * compilation if user enables corresponding warning. Disable it explicitly.
  71  */
  72 #pragma GCC diagnostic ignored "-Wformat-nonliteral"
  73
  74 #define __printf(a, b)  __attribute__((format(printf, a, b)))
  75
  76 static struct bpf_map *bpf_object__add_map(struct bpf_object *obj);
  77 static struct bpf_program *bpf_object__find_prog_by_idx(struct bpf_object *obj,
  78                                                         int idx);
  79 static const struct btf_type *
  80 skip_mods_and_typedefs(const struct btf *btf, __u32 id, __u32 *res_id);
  81
  82 static int __base_pr(enum libbpf_print_level level, const char *format,
  83                      va_list args)
  84 {
  85         if (level == LIBBPF_DEBUG)
  86                 return 0;
  87
  88         return vfprintf(stderr, format, args);
  89 }
  90
  91 static libbpf_print_fn_t __libbpf_pr = __base_pr;
  92
  93 libbpf_print_fn_t libbpf_set_print(libbpf_print_fn_t fn)
  94 {
  95         libbpf_print_fn_t old_print_fn = __libbpf_pr;
  96
  97         __libbpf_pr = fn;
  98         return old_print_fn;
  99 }
 100
 101 __printf(2, 3)
 102 void libbpf_print(enum libbpf_print_level level, const char *format, ...)
 103 {
 104         va_list args;
 105
 106         if (!__libbpf_pr)
 107                 return;
 108
 109         va_start(args, format);
 110         __libbpf_pr(level, format, args);
 111         va_end(args);
 112 }
 113
 114 static void pr_perm_msg(int err)
 115 {
 116         struct rlimit limit;
 117         char buf[100];
 118
 119         if (err != -EPERM || geteuid() != 0)
 120                 return;
 121
 122         err = getrlimit(RLIMIT_MEMLOCK, &limit);
 123         if (err)
 124                 return;
 125
 126         if (limit.rlim_cur == RLIM_INFINITY)
 127                 return;
 128
 129         if (limit.rlim_cur < 1024)
 130                 snprintf(buf, sizeof(buf), "%zu bytes", (size_t)limit.rlim_cur);
 131         else if (limit.rlim_cur < 1024*1024)
 132                 snprintf(buf, sizeof(buf), "%.1f KiB", (double)limit.rlim_cur / 1024);
 133         else
 134                 snprintf(buf, sizeof(buf), "%.1f MiB", (double)limit.rlim_cur / (1024*1024));
 135
 136         pr_warn("permission error while running as root; try raising 'ulimit -l'? current value: %s\n",
 137                 buf);
 138 }
 139
 140 #define STRERR_BUFSIZE  128
 141
 142 /* Copied from tools/perf/util/util.h */
 143 #ifndef zfree
 144 # define zfree(ptr) ({ free(*ptr); *ptr = NULL; })
 145 #endif
 146
 147 #ifndef zclose
 148 # define zclose(fd) ({                  \
 149         int ___err = 0;                 \
 150         if ((fd) >= 0)                  \
 151                 ___err = close((fd));   \
 152         fd = -1;                        \
 153         ___err; })
 154 #endif
 155
 156 #ifdef HAVE_LIBELF_MMAP_SUPPORT
 157 # define LIBBPF_ELF_C_READ_MMAP ELF_C_READ_MMAP
 158 #else
 159 # define LIBBPF_ELF_C_READ_MMAP ELF_C_READ
 160 #endif
 161
 162 static inline __u64 ptr_to_u64(const void *ptr)
 163 {
 164         return (__u64) (unsigned long) ptr;
 165 }
 166
 167 struct bpf_capabilities {
 168         /* v4.14: kernel support for program & map names. */
 169         __u32 name:1;
 170         /* v5.2: kernel support for global data sections. */
 171         __u32 global_data:1;
 172         /* BTF_KIND_FUNC and BTF_KIND_FUNC_PROTO support */
 173         __u32 btf_func:1;
 174         /* BTF_KIND_VAR and BTF_KIND_DATASEC support */
 175         __u32 btf_datasec:1;
 176         /* BPF_F_MMAPABLE is supported for arrays */
 177         __u32 array_mmap:1;
 178         /* BTF_FUNC_GLOBAL is supported */
 179         __u32 btf_func_global:1;
 180 };
 181
 182 enum reloc_type {
 183         RELO_LD64,
 184         RELO_CALL,
 185         RELO_DATA,
 186         RELO_EXTERN,
 187 };
 188
 189 struct reloc_desc {
 190         enum reloc_type type;
 191         int insn_idx;
 192         int map_idx;
 193         int sym_off;
 194 };
 195
 196 /*
 197  * bpf_prog should be a better name but it has been used in
 198  * linux/filter.h.
 199  */
 200 struct bpf_program {
 201         /* Index in elf obj file, for relocation use. */
 202         int idx;
 203         char *name;
 204         int prog_ifindex;
 205         char *section_name;
 206         /* section_name with / replaced by _; makes recursive pinning
 207          * in bpf_object__pin_programs easier
 208          */
 209         char *pin_name;
 210         struct bpf_insn *insns;
 211         size_t insns_cnt, main_prog_cnt;
 212         enum bpf_prog_type type;
 213
 214         struct reloc_desc *reloc_desc;
 215         int nr_reloc;
 216         int log_level;
 217
 218         struct {
 219                 int nr;
 220                 int *fds;
 221         } instances;
 222         bpf_program_prep_t preprocessor;
 223
 224         struct bpf_object *obj;
 225         void *priv;
 226         bpf_program_clear_priv_t clear_priv;
 227
 228         enum bpf_attach_type expected_attach_type;
 229         __u32 attach_btf_id;
 230         __u32 attach_prog_fd;
 231         void *func_info;
 232         __u32 func_info_rec_size;
 233         __u32 func_info_cnt;
 234
 235         struct bpf_capabilities *caps;
 236
 237         void *line_info;
 238         __u32 line_info_rec_size;
 239         __u32 line_info_cnt;
 240         __u32 prog_flags;
 241 };
 242
 243 struct bpf_struct_ops {
 244         const char *tname;
 245         const struct btf_type *type;
 246         struct bpf_program **progs;
 247         __u32 *kern_func_off;
 248         /* e.g. struct tcp_congestion_ops in bpf_prog's btf format */
 249         void *data;
 250         /* e.g. struct bpf_struct_ops_tcp_congestion_ops in
 251          *      btf_vmlinux's format.
 252          * struct bpf_struct_ops_tcp_congestion_ops {
 253          *      [... some other kernel fields ...]
 254          *      struct tcp_congestion_ops data;
 255          * }
 256          * kern_vdata-size == sizeof(struct bpf_struct_ops_tcp_congestion_ops)
 257          * bpf_map__init_kern_struct_ops() will populate the "kern_vdata"
 258          * from "data".
 259          */
 260         void *kern_vdata;
 261         __u32 type_id;
 262 };
 263
 264 #define DATA_SEC ".data"
 265 #define BSS_SEC ".bss"
 266 #define RODATA_SEC ".rodata"
 267 #define KCONFIG_SEC ".kconfig"
 268 #define STRUCT_OPS_SEC ".struct_ops"
 269
 270 enum libbpf_map_type {
 271         LIBBPF_MAP_UNSPEC,
 272         LIBBPF_MAP_DATA,
 273         LIBBPF_MAP_BSS,
 274         LIBBPF_MAP_RODATA,
 275         LIBBPF_MAP_KCONFIG,
 276 };
 277
 278 static const char * const libbpf_type_to_btf_name[] = {
 279         [LIBBPF_MAP_DATA]       = DATA_SEC,
 280         [LIBBPF_MAP_BSS]        = BSS_SEC,
 281         [LIBBPF_MAP_RODATA]     = RODATA_SEC,
 282         [LIBBPF_MAP_KCONFIG]    = KCONFIG_SEC,
 283 };
 284
 285 struct bpf_map {
 286         char *name;
 287         int fd;
 288         int sec_idx;
 289         size_t sec_offset;
 290         int map_ifindex;
 291         int inner_map_fd;
 292         struct bpf_map_def def;
 293         __u32 btf_key_type_id;
 294         __u32 btf_value_type_id;
 295         __u32 btf_vmlinux_value_type_id;
 296         void *priv;
 297         bpf_map_clear_priv_t clear_priv;
 298         enum libbpf_map_type libbpf_type;
 299         void *mmaped;
 300         struct bpf_struct_ops *st_ops;
 301         char *pin_path;
 302         bool pinned;
 303         bool reused;
 304 };
 305
 306 enum extern_type {
 307         EXT_UNKNOWN,
 308         EXT_CHAR,
 309         EXT_BOOL,
 310         EXT_INT,
 311         EXT_TRISTATE,
 312         EXT_CHAR_ARR,
 313 };
 314
 315 struct extern_desc {
 316         const char *name;
 317         int sym_idx;
 318         int btf_id;
 319         enum extern_type type;
 320         int sz;
 321         int align;
 322         int data_off;
 323         bool is_signed;
 324         bool is_weak;
 325         bool is_set;
 326 };
 327
 328 static LIST_HEAD(bpf_objects_list);
 329
 330 struct bpf_object {
 331         char name[BPF_OBJ_NAME_LEN];
 332         char license[64];
 333         __u32 kern_version;
 334
 335         struct bpf_program *programs;
 336         size_t nr_programs;
 337         struct bpf_map *maps;
 338         size_t nr_maps;
 339         size_t maps_cap;
 340
 341         char *kconfig;
 342         struct extern_desc *externs;
 343         int nr_extern;
 344         int kconfig_map_idx;
 345
 346         bool loaded;
 347         bool has_pseudo_calls;
 348
 349         /*
 350          * Information when doing elf related work. Only valid if fd
 351          * is valid.
 352          */
 353         struct {
 354                 int fd;
 355                 const void *obj_buf;
 356                 size_t obj_buf_sz;
 357                 Elf *elf;
 358                 GElf_Ehdr ehdr;
 359                 Elf_Data *symbols;
 360                 Elf_Data *data;
 361                 Elf_Data *rodata;
 362                 Elf_Data *bss;
 363                 Elf_Data *st_ops_data;
 364                 size_t strtabidx;
 365                 struct {
 366                         GElf_Shdr shdr;
 367                         Elf_Data *data;
 368                 } *reloc_sects;
 369                 int nr_reloc_sects;
 370                 int maps_shndx;
 371                 int btf_maps_shndx;
 372                 int text_shndx;
 373                 int symbols_shndx;
 374                 int data_shndx;
 375                 int rodata_shndx;
 376                 int bss_shndx;
 377                 int st_ops_shndx;
 378         } efile;
 379         /*
 380          * All loaded bpf_object is linked in a list, which is
 381          * hidden to caller. bpf_objects__<func> handlers deal with
 382          * all objects.
 383          */
 384         struct list_head list;
 385
 386         struct btf *btf;
 387         /* Parse and load BTF vmlinux if any of the programs in the object need
 388          * it at load time.
 389          */
 390         struct btf *btf_vmlinux;
 391         struct btf_ext *btf_ext;
 392
 393         void *priv;
 394         bpf_object_clear_priv_t clear_priv;
 395
 396         struct bpf_capabilities caps;
 397
 398         char path[];
 399 };
 400 #define obj_elf_valid(o)        ((o)->efile.elf)
 401
 402 void bpf_program__unload(struct bpf_program *prog)
 403 {
 404         int i;
 405
 406         if (!prog)
 407                 return;
 408
 409         /*
 410          * If the object is opened but the program was never loaded,
 411          * it is possible that prog->instances.nr == -1.
 412          */
 413         if (prog->instances.nr > 0) {
 414                 for (i = 0; i < prog->instances.nr; i++)
 415                         zclose(prog->instances.fds[i]);
 416         } else if (prog->instances.nr != -1) {
 417                 pr_warn("Internal error: instances.nr is %d\n",
 418                         prog->instances.nr);
 419         }
 420
 421         prog->instances.nr = -1;
 422         zfree(&prog->instances.fds);
 423
 424         zfree(&prog->func_info);
 425         zfree(&prog->line_info);
 426 }
 427
 428 static void bpf_program__exit(struct bpf_program *prog)
 429 {
 430         if (!prog)
 431                 return;
 432
 433         if (prog->clear_priv)
 434                 prog->clear_priv(prog, prog->priv);
 435
 436         prog->priv = NULL;
 437         prog->clear_priv = NULL;
 438
 439         bpf_program__unload(prog);
 440         zfree(&prog->name);
 441         zfree(&prog->section_name);
 442         zfree(&prog->pin_name);
 443         zfree(&prog->insns);
 444         zfree(&prog->reloc_desc);
 445
 446         prog->nr_reloc = 0;
 447         prog->insns_cnt = 0;
 448         prog->idx = -1;
 449 }
 450
 451 static char *__bpf_program__pin_name(struct bpf_program *prog)
 452 {
 453         char *name, *p;
 454
 455         name = p = strdup(prog->section_name);
 456         while ((p = strchr(p, '/')))
 457                 *p = '_';
 458
 459         return name;
 460 }
 461
 462 static int
 463 bpf_program__init(void *data, size_t size, char *section_name, int idx,
 464                   struct bpf_program *prog)
 465 {
 466         const size_t bpf_insn_sz = sizeof(struct bpf_insn);
 467
 468         if (size == 0 || size % bpf_insn_sz) {
 469                 pr_warn("corrupted section '%s', size: %zu\n",
 470                         section_name, size);
 471                 return -EINVAL;
 472         }
 473
 474         memset(prog, 0, sizeof(*prog));
 475
 476         prog->section_name = strdup(section_name);
 477         if (!prog->section_name) {
 478                 pr_warn("failed to alloc name for prog under section(%d) %s\n",
 479                         idx, section_name);
 480                 goto errout;
 481         }
 482
 483         prog->pin_name = __bpf_program__pin_name(prog);
 484         if (!prog->pin_name) {
 485                 pr_warn("failed to alloc pin name for prog under section(%d) %s\n",
 486                         idx, section_name);
 487                 goto errout;
 488         }
 489
 490         prog->insns = malloc(size);
 491         if (!prog->insns) {
 492                 pr_warn("failed to alloc insns for prog under section %s\n",
 493                         section_name);
 494                 goto errout;
 495         }
 496         prog->insns_cnt = size / bpf_insn_sz;
 497         memcpy(prog->insns, data, size);
 498         prog->idx = idx;
 499         prog->instances.fds = NULL;
 500         prog->instances.nr = -1;
 501         prog->type = BPF_PROG_TYPE_UNSPEC;
 502
 503         return 0;
 504 errout:
 505         bpf_program__exit(prog);
 506         return -ENOMEM;
 507 }
 508
 509 static int
 510 bpf_object__add_program(struct bpf_object *obj, void *data, size_t size,
 511                         char *section_name, int idx)
 512 {
 513         struct bpf_program prog, *progs;
 514         int nr_progs, err;
 515
 516         err = bpf_program__init(data, size, section_name, idx, &prog);
 517         if (err)
 518                 return err;
 519
 520         prog.caps = &obj->caps;
 521         progs = obj->programs;
 522         nr_progs = obj->nr_programs;
 523
 524         progs = reallocarray(progs, nr_progs + 1, sizeof(progs[0]));
 525         if (!progs) {
 526                 /*
 527                  * In this case the original obj->programs
 528                  * is still valid, so don't need special treat for
 529                  * bpf_close_object().
 530                  */
 531                 pr_warn("failed to alloc a new program under section '%s'\n",
 532                         section_name);
 533                 bpf_program__exit(&prog);
 534                 return -ENOMEM;
 535         }
 536
 537         pr_debug("found program %s\n", prog.section_name);
 538         obj->programs = progs;
 539         obj->nr_programs = nr_progs + 1;
 540         prog.obj = obj;
 541         progs[nr_progs] = prog;
 542         return 0;
 543 }
 544
 545 static int
 546 bpf_object__init_prog_names(struct bpf_object *obj)
 547 {
 548         Elf_Data *symbols = obj->efile.symbols;
 549         struct bpf_program *prog;
 550         size_t pi, si;
 551
 552         for (pi = 0; pi < obj->nr_programs; pi++) {
 553                 const char *name = NULL;
 554
 555                 prog = &obj->programs[pi];
 556
 557                 for (si = 0; si < symbols->d_size / sizeof(GElf_Sym) && !name;
 558                      si++) {
 559                         GElf_Sym sym;
 560
 561                         if (!gelf_getsym(symbols, si, &sym))
 562                                 continue;
 563                         if (sym.st_shndx != prog->idx)
 564                                 continue;
 565                         if (GELF_ST_BIND(sym.st_info) != STB_GLOBAL)
 566                                 continue;
 567
 568                         name = elf_strptr(obj->efile.elf,
 569                                           obj->efile.strtabidx,
 570                                           sym.st_name);
 571                         if (!name) {
 572                                 pr_warn("failed to get sym name string for prog %s\n",
 573                                         prog->section_name);
 574                                 return -LIBBPF_ERRNO__LIBELF;
 575                         }
 576                 }
 577
 578                 if (!name && prog->idx == obj->efile.text_shndx)
 579                         name = ".text";
 580
 581                 if (!name) {
 582                         pr_warn("failed to find sym for prog %s\n",
 583                                 prog->section_name);
 584                         return -EINVAL;
 585                 }
 586
 587                 prog->name = strdup(name);
 588                 if (!prog->name) {
 589                         pr_warn("failed to allocate memory for prog sym %s\n",
 590                                 name);
 591                         return -ENOMEM;
 592                 }
 593         }
 594
 595         return 0;
 596 }
 597
 598 static __u32 get_kernel_version(void)
 599 {
 600         __u32 major, minor, patch;
 601         struct utsname info;
 602
 603         uname(&info);
 604         if (sscanf(info.release, "%u.%u.%u", &major, &minor, &patch) != 3)
 605                 return 0;
 606         return KERNEL_VERSION(major, minor, patch);
 607 }
 608
 609 static const struct btf_member *
 610 find_member_by_offset(const struct btf_type *t, __u32 bit_offset)
 611 {
 612         struct btf_member *m;
 613         int i;
 614
 615         for (i = 0, m = btf_members(t); i < btf_vlen(t); i++, m++) {
 616                 if (btf_member_bit_offset(t, i) == bit_offset)
 617                         return m;
 618         }
 619
 620         return NULL;
 621 }
 622
 623 static const struct btf_member *
 624 find_member_by_name(const struct btf *btf, const struct btf_type *t,
 625                     const char *name)
 626 {
 627         struct btf_member *m;
 628         int i;
 629
 630         for (i = 0, m = btf_members(t); i < btf_vlen(t); i++, m++) {
 631                 if (!strcmp(btf__name_by_offset(btf, m->name_off), name))
 632                         return m;
 633         }
 634
 635         return NULL;
 636 }
 637
 638 #define STRUCT_OPS_VALUE_PREFIX "bpf_struct_ops_"
 639 static int find_btf_by_prefix_kind(const struct btf *btf, const char *prefix,
 640                                    const char *name, __u32 kind);
 641
 642 static int
 643 find_struct_ops_kern_types(const struct btf *btf, const char *tname,
 644                            const struct btf_type **type, __u32 *type_id,
 645                            const struct btf_type **vtype, __u32 *vtype_id,
 646                            const struct btf_member **data_member)
 647 {
 648         const struct btf_type *kern_type, *kern_vtype;
 649         const struct btf_member *kern_data_member;
 650         __s32 kern_vtype_id, kern_type_id;
 651         __u32 i;
 652
 653         kern_type_id = btf__find_by_name_kind(btf, tname, BTF_KIND_STRUCT);
 654         if (kern_type_id < 0) {
 655                 pr_warn("struct_ops init_kern: struct %s is not found in kernel BTF\n",
 656                         tname);
 657                 return kern_type_id;
 658         }
 659         kern_type = btf__type_by_id(btf, kern_type_id);
 660
 661         /* Find the corresponding "map_value" type that will be used
 662          * in map_update(BPF_MAP_TYPE_STRUCT_OPS).  For example,
 663          * find "struct bpf_struct_ops_tcp_congestion_ops" from the
 664          * btf_vmlinux.
 665          */
 666         kern_vtype_id = find_btf_by_prefix_kind(btf, STRUCT_OPS_VALUE_PREFIX,
 667                                                 tname, BTF_KIND_STRUCT);
 668         if (kern_vtype_id < 0) {
 669                 pr_warn("struct_ops init_kern: struct %s%s is not found in kernel BTF\n",
 670                         STRUCT_OPS_VALUE_PREFIX, tname);
 671                 return kern_vtype_id;
 672         }
 673         kern_vtype = btf__type_by_id(btf, kern_vtype_id);
 674
 675         /* Find "struct tcp_congestion_ops" from
 676          * struct bpf_struct_ops_tcp_congestion_ops {
 677          *      [ ... ]
 678          *      struct tcp_congestion_ops data;
 679          * }
 680          */
 681         kern_data_member = btf_members(kern_vtype);
 682         for (i = 0; i < btf_vlen(kern_vtype); i++, kern_data_member++) {
 683                 if (kern_data_member->type == kern_type_id)
 684                         break;
 685         }
 686         if (i == btf_vlen(kern_vtype)) {
 687                 pr_warn("struct_ops init_kern: struct %s data is not found in struct %s%s\n",
 688                         tname, STRUCT_OPS_VALUE_PREFIX, tname);
 689                 return -EINVAL;
 690         }
 691
 692         *type = kern_type;
 693         *type_id = kern_type_id;
 694         *vtype = kern_vtype;
 695         *vtype_id = kern_vtype_id;
 696         *data_member = kern_data_member;
 697
 698         return 0;
 699 }
 700
 701 static bool bpf_map__is_struct_ops(const struct bpf_map *map)
 702 {
 703         return map->def.type == BPF_MAP_TYPE_STRUCT_OPS;
 704 }
 705
 706 /* Init the map's fields that depend on kern_btf */
 707 static int bpf_map__init_kern_struct_ops(struct bpf_map *map,
 708                                          const struct btf *btf,
 709                                          const struct btf *kern_btf)
 710 {
 711         const struct btf_member *member, *kern_member, *kern_data_member;
 712         const struct btf_type *type, *kern_type, *kern_vtype;
 713         __u32 i, kern_type_id, kern_vtype_id, kern_data_off;
 714         struct bpf_struct_ops *st_ops;
 715         void *data, *kern_data;
 716         const char *tname;
 717         int err;
 718
 719         st_ops = map->st_ops;
 720         type = st_ops->type;
 721         tname = st_ops->tname;
 722         err = find_struct_ops_kern_types(kern_btf, tname,
 723                                          &kern_type, &kern_type_id,
 724                                          &kern_vtype, &kern_vtype_id,
 725                                          &kern_data_member);
 726         if (err)
 727                 return err;
 728
 729         pr_debug("struct_ops init_kern %s: type_id:%u kern_type_id:%u kern_vtype_id:%u\n",
 730                  map->name, st_ops->type_id, kern_type_id, kern_vtype_id);
 731
 732         map->def.value_size = kern_vtype->size;
 733         map->btf_vmlinux_value_type_id = kern_vtype_id;
 734
 735         st_ops->kern_vdata = calloc(1, kern_vtype->size);
 736         if (!st_ops->kern_vdata)
 737                 return -ENOMEM;
 738
 739         data = st_ops->data;
 740         kern_data_off = kern_data_member->offset / 8;
 741         kern_data = st_ops->kern_vdata + kern_data_off;
 742
 743         member = btf_members(type);
 744         for (i = 0; i < btf_vlen(type); i++, member++) {
 745                 const struct btf_type *mtype, *kern_mtype;
 746                 __u32 mtype_id, kern_mtype_id;
 747                 void *mdata, *kern_mdata;
 748                 __s64 msize, kern_msize;
 749                 __u32 moff, kern_moff;
 750                 __u32 kern_member_idx;
 751                 const char *mname;
 752
 753                 mname = btf__name_by_offset(btf, member->name_off);
 754                 kern_member = find_member_by_name(kern_btf, kern_type, mname);
 755                 if (!kern_member) {
 756                         pr_warn("struct_ops init_kern %s: Cannot find member %s in kernel BTF\n",
 757                                 map->name, mname);
 758                         return -ENOTSUP;
 759                 }
 760
 761                 kern_member_idx = kern_member - btf_members(kern_type);
 762                 if (btf_member_bitfield_size(type, i) ||
 763                     btf_member_bitfield_size(kern_type, kern_member_idx)) {
 764                         pr_warn("struct_ops init_kern %s: bitfield %s is not supported\n",
 765                                 map->name, mname);
 766                         return -ENOTSUP;
 767                 }
 768
 769                 moff = member->offset / 8;
 770                 kern_moff = kern_member->offset / 8;
 771
 772                 mdata = data + moff;
 773                 kern_mdata = kern_data + kern_moff;
 774
 775                 mtype = skip_mods_and_typedefs(btf, member->type, &mtype_id);
 776                 kern_mtype = skip_mods_and_typedefs(kern_btf, kern_member->type,
 777                                                     &kern_mtype_id);
 778                 if (BTF_INFO_KIND(mtype->info) !=
 779                     BTF_INFO_KIND(kern_mtype->info)) {
 780                         pr_warn("struct_ops init_kern %s: Unmatched member type %s %u != %u(kernel)\n",
 781                                 map->name, mname, BTF_INFO_KIND(mtype->info),
 782                                 BTF_INFO_KIND(kern_mtype->info));
 783                         return -ENOTSUP;
 784                 }
 785
 786                 if (btf_is_ptr(mtype)) {
 787                         struct bpf_program *prog;
 788
 789                         mtype = skip_mods_and_typedefs(btf, mtype->type, &mtype_id);
 790                         kern_mtype = skip_mods_and_typedefs(kern_btf,
 791                                                             kern_mtype->type,
 792                                                             &kern_mtype_id);
 793                         if (!btf_is_func_proto(mtype) ||
 794                             !btf_is_func_proto(kern_mtype)) {
 795                                 pr_warn("struct_ops init_kern %s: non func ptr %s is not supported\n",
 796                                         map->name, mname);
 797                                 return -ENOTSUP;
 798                         }
 799
 800                         prog = st_ops->progs[i];
 801                         if (!prog) {
 802                                 pr_debug("struct_ops init_kern %s: func ptr %s is not set\n",
 803                                          map->name, mname);
 804                                 continue;
 805                         }
 806
 807                         prog->attach_btf_id = kern_type_id;
 808                         prog->expected_attach_type = kern_member_idx;
 809
 810                         st_ops->kern_func_off[i] = kern_data_off + kern_moff;
 811
 812                         pr_debug("struct_ops init_kern %s: func ptr %s is set to prog %s from data(+%u) to kern_data(+%u)\n",
 813                                  map->name, mname, prog->name, moff,
 814                                  kern_moff);
 815
 816                         continue;
 817                 }
 818
 819                 msize = btf__resolve_size(btf, mtype_id);
 820                 kern_msize = btf__resolve_size(kern_btf, kern_mtype_id);
 821                 if (msize < 0 || kern_msize < 0 || msize != kern_msize) {
 822                         pr_warn("struct_ops init_kern %s: Error in size of member %s: %zd != %zd(kernel)\n",
 823                                 map->name, mname, (ssize_t)msize,
 824                                 (ssize_t)kern_msize);
 825                         return -ENOTSUP;
 826                 }
 827
 828                 pr_debug("struct_ops init_kern %s: copy %s %u bytes from data(+%u) to kern_data(+%u)\n",
 829                          map->name, mname, (unsigned int)msize,
 830                          moff, kern_moff);
 831                 memcpy(kern_mdata, mdata, msize);
 832         }
 833
 834         return 0;
 835 }
 836
 837 static int bpf_object__init_kern_struct_ops_maps(struct bpf_object *obj)
 838 {
 839         struct bpf_map *map;
 840         size_t i;
 841         int err;
 842
 843         for (i = 0; i < obj->nr_maps; i++) {
 844                 map = &obj->maps[i];
 845
 846                 if (!bpf_map__is_struct_ops(map))
 847                         continue;
 848
 849                 err = bpf_map__init_kern_struct_ops(map, obj->btf,
 850                                                     obj->btf_vmlinux);
 851                 if (err)
 852                         return err;
 853         }
 854
 855         return 0;
 856 }
 857
 858 static int bpf_object__init_struct_ops_maps(struct bpf_object *obj)
 859 {
 860         const struct btf_type *type, *datasec;
 861         const struct btf_var_secinfo *vsi;
 862         struct bpf_struct_ops *st_ops;
 863         const char *tname, *var_name;
 864         __s32 type_id, datasec_id;
 865         const struct btf *btf;
 866         struct bpf_map *map;
 867         __u32 i;
 868
 869         if (obj->efile.st_ops_shndx == -1)
 870                 return 0;
 871
 872         btf = obj->btf;
 873         datasec_id = btf__find_by_name_kind(btf, STRUCT_OPS_SEC,
 874                                             BTF_KIND_DATASEC);
 875         if (datasec_id < 0) {
 876                 pr_warn("struct_ops init: DATASEC %s not found\n",
 877                         STRUCT_OPS_SEC);
 878                 return -EINVAL;
 879         }
 880
 881         datasec = btf__type_by_id(btf, datasec_id);
 882         vsi = btf_var_secinfos(datasec);
 883         for (i = 0; i < btf_vlen(datasec); i++, vsi++) {
 884                 type = btf__type_by_id(obj->btf, vsi->type);
 885                 var_name = btf__name_by_offset(obj->btf, type->name_off);
 886
 887                 type_id = btf__resolve_type(obj->btf, vsi->type);
 888                 if (type_id < 0) {
 889                         pr_warn("struct_ops init: Cannot resolve var type_id %u in DATASEC %s\n",
 890                                 vsi->type, STRUCT_OPS_SEC);
 891                         return -EINVAL;
 892                 }
 893
 894                 type = btf__type_by_id(obj->btf, type_id);
 895                 tname = btf__name_by_offset(obj->btf, type->name_off);
 896                 if (!tname[0]) {
 897                         pr_warn("struct_ops init: anonymous type is not supported\n");
 898                         return -ENOTSUP;
 899                 }
 900                 if (!btf_is_struct(type)) {
 901                         pr_warn("struct_ops init: %s is not a struct\n", tname);
 902                         return -EINVAL;
 903                 }
 904
 905                 map = bpf_object__add_map(obj);
 906                 if (IS_ERR(map))
 907                         return PTR_ERR(map);
 908
 909                 map->sec_idx = obj->efile.st_ops_shndx;
 910                 map->sec_offset = vsi->offset;
 911                 map->name = strdup(var_name);
 912                 if (!map->name)
 913                         return -ENOMEM;
 914
 915                 map->def.type = BPF_MAP_TYPE_STRUCT_OPS;
 916                 map->def.key_size = sizeof(int);
 917                 map->def.value_size = type->size;
 918                 map->def.max_entries = 1;
 919
 920                 map->st_ops = calloc(1, sizeof(*map->st_ops));
 921                 if (!map->st_ops)
 922                         return -ENOMEM;
 923                 st_ops = map->st_ops;
 924                 st_ops->data = malloc(type->size);
 925                 st_ops->progs = calloc(btf_vlen(type), sizeof(*st_ops->progs));
 926                 st_ops->kern_func_off = malloc(btf_vlen(type) *
 927                                                sizeof(*st_ops->kern_func_off));
 928                 if (!st_ops->data || !st_ops->progs || !st_ops->kern_func_off)
 929                         return -ENOMEM;
 930
 931                 if (vsi->offset + type->size > obj->efile.st_ops_data->d_size) {
 932                         pr_warn("struct_ops init: var %s is beyond the end of DATASEC %s\n",
 933                                 var_name, STRUCT_OPS_SEC);
 934                         return -EINVAL;
 935                 }
 936
 937                 memcpy(st_ops->data,
 938                        obj->efile.st_ops_data->d_buf + vsi->offset,
 939                        type->size);
 940                 st_ops->tname = tname;
 941                 st_ops->type = type;
 942                 st_ops->type_id = type_id;
 943
 944                 pr_debug("struct_ops init: struct %s(type_id=%u) %s found at offset %u\n",
 945                          tname, type_id, var_name, vsi->offset);
 946         }
 947
 948         return 0;
 949 }
 950
 951 static struct bpf_object *bpf_object__new(const char *path,
 952                                           const void *obj_buf,
 953                                           size_t obj_buf_sz,
 954                                           const char *obj_name)
 955 {
 956         struct bpf_object *obj;
 957         char *end;
 958
 959         obj = calloc(1, sizeof(struct bpf_object) + strlen(path) + 1);
 960         if (!obj) {
 961                 pr_warn("alloc memory failed for %s\n", path);
 962                 return ERR_PTR(-ENOMEM);
 963         }
 964
 965         strcpy(obj->path, path);
 966         if (obj_name) {
 967                 strncpy(obj->name, obj_name, sizeof(obj->name) - 1);
 968                 obj->name[sizeof(obj->name) - 1] = 0;
 969         } else {
 970                 /* Using basename() GNU version which doesn't modify arg. */
 971                 strncpy(obj->name, basename((void *)path),
 972                         sizeof(obj->name) - 1);
 973                 end = strchr(obj->name, '.');
 974                 if (end)
 975                         *end = 0;
 976         }
 977
 978         obj->efile.fd = -1;
 979         /*
 980          * Caller of this function should also call
 981          * bpf_object__elf_finish() after data collection to return
 982          * obj_buf to user. If not, we should duplicate the buffer to
 983          * avoid user freeing them before elf finish.
 984          */
 985         obj->efile.obj_buf = obj_buf;
 986         obj->efile.obj_buf_sz = obj_buf_sz;
 987         obj->efile.maps_shndx = -1;
 988         obj->efile.btf_maps_shndx = -1;
 989         obj->efile.data_shndx = -1;
 990         obj->efile.rodata_shndx = -1;
 991         obj->efile.bss_shndx = -1;
 992         obj->efile.st_ops_shndx = -1;
 993         obj->kconfig_map_idx = -1;
 994
 995         obj->kern_version = get_kernel_version();
 996         obj->loaded = false;
 997
 998         INIT_LIST_HEAD(&obj->list);
 999         list_add(&obj->list, &bpf_objects_list);
1000         return obj;
1001 }
1002
1003 static void bpf_object__elf_finish(struct bpf_object *obj)
1004 {
1005         if (!obj_elf_valid(obj))
1006                 return;
1007
1008         if (obj->efile.elf) {
1009                 elf_end(obj->efile.elf);
1010                 obj->efile.elf = NULL;
1011         }
1012         obj->efile.symbols = NULL;
1013         obj->efile.data = NULL;
1014         obj->efile.rodata = NULL;
1015         obj->efile.bss = NULL;
1016         obj->efile.st_ops_data = NULL;
1017
1018         zfree(&obj->efile.reloc_sects);
1019         obj->efile.nr_reloc_sects = 0;
1020         zclose(obj->efile.fd);
1021         obj->efile.obj_buf = NULL;
1022         obj->efile.obj_buf_sz = 0;
1023 }
1024
1025 static int bpf_object__elf_init(struct bpf_object *obj)
1026 {
1027         int err = 0;
1028         GElf_Ehdr *ep;
1029
1030         if (obj_elf_valid(obj)) {
1031                 pr_warn("elf init: internal error\n");
1032                 return -LIBBPF_ERRNO__LIBELF;
1033         }
1034
1035         if (obj->efile.obj_buf_sz > 0) {
1036                 /*
1037                  * obj_buf should have been validated by
1038                  * bpf_object__open_buffer().
1039                  */
1040                 obj->efile.elf = elf_memory((char *)obj->efile.obj_buf,
1041                                             obj->efile.obj_buf_sz);
1042         } else {
1043                 obj->efile.fd = open(obj->path, O_RDONLY);
1044                 if (obj->efile.fd < 0) {
1045                         char errmsg[STRERR_BUFSIZE], *cp;
1046
1047                         err = -errno;
1048                         cp = libbpf_strerror_r(err, errmsg, sizeof(errmsg));
1049                         pr_warn("failed to open %s: %s\n", obj->path, cp);
1050                         return err;
1051                 }
1052
1053                 obj->efile.elf = elf_begin(obj->efile.fd,
1054                                            LIBBPF_ELF_C_READ_MMAP, NULL);
1055         }
1056
1057         if (!obj->efile.elf) {
1058                 pr_warn("failed to open %s as ELF file\n", obj->path);
1059                 err = -LIBBPF_ERRNO__LIBELF;
1060                 goto errout;
1061         }
1062
1063         if (!gelf_getehdr(obj->efile.elf, &obj->efile.ehdr)) {
1064                 pr_warn("failed to get EHDR from %s\n", obj->path);
1065                 err = -LIBBPF_ERRNO__FORMAT;
1066                 goto errout;
1067         }
1068         ep = &obj->efile.ehdr;
1069
1070         /* Old LLVM set e_machine to EM_NONE */
1071         if (ep->e_type != ET_REL ||
1072             (ep->e_machine && ep->e_machine != EM_BPF)) {
1073                 pr_warn("%s is not an eBPF object file\n", obj->path);
1074                 err = -LIBBPF_ERRNO__FORMAT;
1075                 goto errout;
1076         }
1077
1078         return 0;
1079 errout:
1080         bpf_object__elf_finish(obj);
1081         return err;
1082 }
1083
1084 static int bpf_object__check_endianness(struct bpf_object *obj)
1085 {
1086 #if __BYTE_ORDER == __LITTLE_ENDIAN
1087         if (obj->efile.ehdr.e_ident[EI_DATA] == ELFDATA2LSB)
1088                 return 0;
1089 #elif __BYTE_ORDER == __BIG_ENDIAN
1090         if (obj->efile.ehdr.e_ident[EI_DATA] == ELFDATA2MSB)
1091                 return 0;
1092 #else
1093 # error "Unrecognized __BYTE_ORDER__"
1094 #endif
1095         pr_warn("endianness mismatch.\n");
1096         return -LIBBPF_ERRNO__ENDIAN;
1097 }
1098
1099 static int
1100 bpf_object__init_license(struct bpf_object *obj, void *data, size_t size)
1101 {
1102         memcpy(obj->license, data, min(size, sizeof(obj->license) - 1));
1103         pr_debug("license of %s is %s\n", obj->path, obj->license);
1104         return 0;
1105 }
1106
1107 static int
1108 bpf_object__init_kversion(struct bpf_object *obj, void *data, size_t size)
1109 {
1110         __u32 kver;
1111
1112         if (size != sizeof(kver)) {
1113                 pr_warn("invalid kver section in %s\n", obj->path);
1114                 return -LIBBPF_ERRNO__FORMAT;
1115         }
1116         memcpy(&kver, data, sizeof(kver));
1117         obj->kern_version = kver;
1118         pr_debug("kernel version of %s is %x\n", obj->path, obj->kern_version);
1119         return 0;
1120 }
1121
1122 static bool bpf_map_type__is_map_in_map(enum bpf_map_type type)
1123 {
1124         if (type == BPF_MAP_TYPE_ARRAY_OF_MAPS ||
1125             type == BPF_MAP_TYPE_HASH_OF_MAPS)
1126                 return true;
1127         return false;
1128 }
1129
1130 static int bpf_object_search_section_size(const struct bpf_object *obj,
1131                                           const char *name, size_t *d_size)
1132 {
1133         const GElf_Ehdr *ep = &obj->efile.ehdr;
1134         Elf *elf = obj->efile.elf;
1135         Elf_Scn *scn = NULL;
1136         int idx = 0;
1137
1138         while ((scn = elf_nextscn(elf, scn)) != NULL) {
1139                 const char *sec_name;
1140                 Elf_Data *data;
1141                 GElf_Shdr sh;
1142
1143                 idx++;
1144                 if (gelf_getshdr(scn, &sh) != &sh) {
1145                         pr_warn("failed to get section(%d) header from %s\n",
1146                                 idx, obj->path);
1147                         return -EIO;
1148                 }
1149
1150                 sec_name = elf_strptr(elf, ep->e_shstrndx, sh.sh_name);
1151                 if (!sec_name) {
1152                         pr_warn("failed to get section(%d) name from %s\n",
1153                                 idx, obj->path);
1154                         return -EIO;
1155                 }
1156
1157                 if (strcmp(name, sec_name))
1158                         continue;
1159
1160                 data = elf_getdata(scn, 0);
1161                 if (!data) {
1162                         pr_warn("failed to get section(%d) data from %s(%s)\n",
1163                                 idx, name, obj->path);
1164                         return -EIO;
1165                 }
1166
1167                 *d_size = data->d_size;
1168                 return 0;
1169         }
1170
1171         return -ENOENT;
1172 }
1173
1174 int bpf_object__section_size(const struct bpf_object *obj, const char *name,
1175                              __u32 *size)
1176 {
1177         int ret = -ENOENT;
1178         size_t d_size;
1179
1180         *size = 0;
1181         if (!name) {
1182                 return -EINVAL;
1183         } else if (!strcmp(name, DATA_SEC)) {
1184                 if (obj->efile.data)
1185                         *size = obj->efile.data->d_size;
1186         } else if (!strcmp(name, BSS_SEC)) {
1187                 if (obj->efile.bss)
1188                         *size = obj->efile.bss->d_size;
1189         } else if (!strcmp(name, RODATA_SEC)) {
1190                 if (obj->efile.rodata)
1191                         *size = obj->efile.rodata->d_size;
1192         } else if (!strcmp(name, STRUCT_OPS_SEC)) {
1193                 if (obj->efile.st_ops_data)
1194                         *size = obj->efile.st_ops_data->d_size;
1195         } else {
1196                 ret = bpf_object_search_section_size(obj, name, &d_size);
1197                 if (!ret)
1198                         *size = d_size;
1199         }
1200
1201         return *size ? 0 : ret;
1202 }
1203
1204 int bpf_object__variable_offset(const struct bpf_object *obj, const char *name,
1205                                 __u32 *off)
1206 {
1207         Elf_Data *symbols = obj->efile.symbols;
1208         const char *sname;
1209         size_t si;
1210
1211         if (!name || !off)
1212                 return -EINVAL;
1213
1214         for (si = 0; si < symbols->d_size / sizeof(GElf_Sym); si++) {
1215                 GElf_Sym sym;
1216
1217                 if (!gelf_getsym(symbols, si, &sym))
1218                         continue;
1219                 if (GELF_ST_BIND(sym.st_info) != STB_GLOBAL ||
1220                     GELF_ST_TYPE(sym.st_info) != STT_OBJECT)
1221                         continue;
1222
1223                 sname = elf_strptr(obj->efile.elf, obj->efile.strtabidx,
1224                                    sym.st_name);
1225                 if (!sname) {
1226                         pr_warn("failed to get sym name string for var %s\n",
1227                                 name);
1228                         return -EIO;
1229                 }
1230                 if (strcmp(name, sname) == 0) {
1231                         *off = sym.st_value;
1232                         return 0;
1233                 }
1234         }
1235
1236         return -ENOENT;
1237 }
1238
1239 static struct bpf_map *bpf_object__add_map(struct bpf_object *obj)
1240 {
1241         struct bpf_map *new_maps;
1242         size_t new_cap;
1243         int i;
1244
1245         if (obj->nr_maps < obj->maps_cap)
1246                 return &obj->maps[obj->nr_maps++];
1247
1248         new_cap = max((size_t)4, obj->maps_cap * 3 / 2);
1249         new_maps = realloc(obj->maps, new_cap * sizeof(*obj->maps));
1250         if (!new_maps) {
1251                 pr_warn("alloc maps for object failed\n");
1252                 return ERR_PTR(-ENOMEM);
1253         }
1254
1255         obj->maps_cap = new_cap;
1256         obj->maps = new_maps;
1257
1258         /* zero out new maps */
1259         memset(obj->maps + obj->nr_maps, 0,
1260                (obj->maps_cap - obj->nr_maps) * sizeof(*obj->maps));
1261         /*
1262          * fill all fd with -1 so won't close incorrect fd (fd=0 is stdin)
1263          * when failure (zclose won't close negative fd)).
1264          */
1265         for (i = obj->nr_maps; i < obj->maps_cap; i++) {
1266                 obj->maps[i].fd = -1;
1267                 obj->maps[i].inner_map_fd = -1;
1268         }
1269
1270         return &obj->maps[obj->nr_maps++];
1271 }
1272
1273 static size_t bpf_map_mmap_sz(const struct bpf_map *map)
1274 {
1275         long page_sz = sysconf(_SC_PAGE_SIZE);
1276         size_t map_sz;
1277
1278         map_sz = (size_t)roundup(map->def.value_size, 8) * map->def.max_entries;
1279         map_sz = roundup(map_sz, page_sz);
1280         return map_sz;
1281 }
1282
1283 static char *internal_map_name(struct bpf_object *obj,
1284                                enum libbpf_map_type type)
1285 {
1286         char map_name[BPF_OBJ_NAME_LEN];
1287         const char *sfx = libbpf_type_to_btf_name[type];
1288         int sfx_len = max((size_t)7, strlen(sfx));
1289         int pfx_len = min((size_t)BPF_OBJ_NAME_LEN - sfx_len - 1,
1290                           strlen(obj->name));
1291
1292         snprintf(map_name, sizeof(map_name), "%.*s%.*s", pfx_len, obj->name,
1293                  sfx_len, libbpf_type_to_btf_name[type]);
1294
1295         return strdup(map_name);
1296 }
1297
1298 static int
1299 bpf_object__init_internal_map(struct bpf_object *obj, enum libbpf_map_type type,
1300                               int sec_idx, void *data, size_t data_sz)
1301 {
1302         struct bpf_map_def *def;
1303         struct bpf_map *map;
1304         int err;
1305
1306         map = bpf_object__add_map(obj);
1307         if (IS_ERR(map))
1308                 return PTR_ERR(map);
1309
1310         map->libbpf_type = type;
1311         map->sec_idx = sec_idx;
1312         map->sec_offset = 0;
1313         map->name = internal_map_name(obj, type);
1314         if (!map->name) {
1315                 pr_warn("failed to alloc map name\n");
1316                 return -ENOMEM;
1317         }
1318
1319         def = &map->def;
1320         def->type = BPF_MAP_TYPE_ARRAY;
1321         def->key_size = sizeof(int);
1322         def->value_size = data_sz;
1323         def->max_entries = 1;
1324         def->map_flags = type == LIBBPF_MAP_RODATA || type == LIBBPF_MAP_KCONFIG
1325                          ? BPF_F_RDONLY_PROG : 0;
1326         def->map_flags |= BPF_F_MMAPABLE;
1327
1328         pr_debug("map '%s' (global data): at sec_idx %d, offset %zu, flags %x.\n",
1329                  map->name, map->sec_idx, map->sec_offset, def->map_flags);
1330
1331         map->mmaped = mmap(NULL, bpf_map_mmap_sz(map), PROT_READ | PROT_WRITE,
1332                            MAP_SHARED | MAP_ANONYMOUS, -1, 0);
1333         if (map->mmaped == MAP_FAILED) {
1334                 err = -errno;
1335                 map->mmaped = NULL;
1336                 pr_warn("failed to alloc map '%s' content buffer: %d\n",
1337                         map->name, err);
1338                 zfree(&map->name);
1339                 return err;
1340         }
1341
1342         if (data)
1343                 memcpy(map->mmaped, data, data_sz);
1344
1345         pr_debug("map %td is \"%s\"\n", map - obj->maps, map->name);
1346         return 0;
1347 }
1348
1349 static int bpf_object__init_global_data_maps(struct bpf_object *obj)
1350 {
1351         int err;
1352
1353         /*
1354          * Populate obj->maps with libbpf internal maps.
1355          */
1356         if (obj->efile.data_shndx >= 0) {
1357                 err = bpf_object__init_internal_map(obj, LIBBPF_MAP_DATA,
1358                                                     obj->efile.data_shndx,
1359                                                     obj->efile.data->d_buf,
1360                                                     obj->efile.data->d_size);
1361                 if (err)
1362                         return err;
1363         }
1364         if (obj->efile.rodata_shndx >= 0) {
1365                 err = bpf_object__init_internal_map(obj, LIBBPF_MAP_RODATA,
1366                                                     obj->efile.rodata_shndx,
1367                                                     obj->efile.rodata->d_buf,
1368                                                     obj->efile.rodata->d_size);
1369                 if (err)
1370                         return err;
1371         }
1372         if (obj->efile.bss_shndx >= 0) {
1373                 err = bpf_object__init_internal_map(obj, LIBBPF_MAP_BSS,
1374                                                     obj->efile.bss_shndx,
1375                                                     NULL,
1376                                                     obj->efile.bss->d_size);
1377                 if (err)
1378                         return err;
1379         }
1380         return 0;
1381 }
1382
1383
1384 static struct extern_desc *find_extern_by_name(const struct bpf_object *obj,
1385                                                const void *name)
1386 {
1387         int i;
1388
1389         for (i = 0; i < obj->nr_extern; i++) {
1390                 if (strcmp(obj->externs[i].name, name) == 0)
1391                         return &obj->externs[i];
1392         }
1393         return NULL;
1394 }
1395
1396 static int set_ext_value_tri(struct extern_desc *ext, void *ext_val,
1397                              char value)
1398 {
1399         switch (ext->type) {
1400         case EXT_BOOL:
1401                 if (value == 'm') {
1402                         pr_warn("extern %s=%c should be tristate or char\n",
1403                                 ext->name, value);
1404                         return -EINVAL;
1405                 }
1406                 *(bool *)ext_val = value == 'y' ? true : false;
1407                 break;
1408         case EXT_TRISTATE:
1409                 if (value == 'y')
1410                         *(enum libbpf_tristate *)ext_val = TRI_YES;
1411                 else if (value == 'm')
1412                         *(enum libbpf_tristate *)ext_val = TRI_MODULE;
1413                 else /* value == 'n' */
1414                         *(enum libbpf_tristate *)ext_val = TRI_NO;
1415                 break;
1416         case EXT_CHAR:
1417                 *(char *)ext_val = value;
1418                 break;
1419         case EXT_UNKNOWN:
1420         case EXT_INT:
1421         case EXT_CHAR_ARR:
1422         default:
1423                 pr_warn("extern %s=%c should be bool, tristate, or char\n",
1424                         ext->name, value);
1425                 return -EINVAL;
1426         }
1427         ext->is_set = true;
1428         return 0;
1429 }
1430
1431 static int set_ext_value_str(struct extern_desc *ext, char *ext_val,
1432                              const char *value)
1433 {
1434         size_t len;
1435
1436         if (ext->type != EXT_CHAR_ARR) {
1437                 pr_warn("extern %s=%s should char array\n", ext->name, value);
1438                 return -EINVAL;
1439         }
1440
1441         len = strlen(value);
1442         if (value[len - 1] != '"') {
1443                 pr_warn("extern '%s': invalid string config '%s'\n",
1444                         ext->name, value);
1445                 return -EINVAL;
1446         }
1447
1448         /* strip quotes */
1449         len -= 2;
1450         if (len >= ext->sz) {
1451                 pr_warn("extern '%s': long string config %s of (%zu bytes) truncated to %d bytes\n",
1452                         ext->name, value, len, ext->sz - 1);
1453                 len = ext->sz - 1;
1454         }
1455         memcpy(ext_val, value + 1, len);
1456         ext_val[len] = '\0';
1457         ext->is_set = true;
1458         return 0;
1459 }
1460
1461 static int parse_u64(const char *value, __u64 *res)
1462 {
1463         char *value_end;
1464         int err;
1465
1466         errno = 0;
1467         *res = strtoull(value, &value_end, 0);
1468         if (errno) {
1469                 err = -errno;
1470                 pr_warn("failed to parse '%s' as integer: %d\n", value, err);
1471                 return err;
1472         }
1473         if (*value_end) {
1474                 pr_warn("failed to parse '%s' as integer completely\n", value);
1475                 return -EINVAL;
1476         }
1477         return 0;
1478 }
1479
1480 static bool is_ext_value_in_range(const struct extern_desc *ext, __u64 v)
1481 {
1482         int bit_sz = ext->sz * 8;
1483
1484         if (ext->sz == 8)
1485                 return true;
1486
1487         /* Validate that value stored in u64 fits in integer of `ext->sz`
1488          * bytes size without any loss of information. If the target integer
1489          * is signed, we rely on the following limits of integer type of
1490          * Y bits and subsequent transformation:
1491          *
1492          *     -2^(Y-1) <= X           <= 2^(Y-1) - 1
1493          *            0 <= X + 2^(Y-1) <= 2^Y - 1
1494          *            0 <= X + 2^(Y-1) <  2^Y
1495          *
1496          *  For unsigned target integer, check that all the (64 - Y) bits are
1497          *  zero.
1498          */
1499         if (ext->is_signed)
1500                 return v + (1ULL << (bit_sz - 1)) < (1ULL << bit_sz);
1501         else
1502                 return (v >> bit_sz) == 0;
1503 }
1504
1505 static int set_ext_value_num(struct extern_desc *ext, void *ext_val,
1506                              __u64 value)
1507 {
1508         if (ext->type != EXT_INT && ext->type != EXT_CHAR) {
1509                 pr_warn("extern %s=%llu should be integer\n",
1510                         ext->name, (unsigned long long)value);
1511                 return -EINVAL;
1512         }
1513         if (!is_ext_value_in_range(ext, value)) {
1514                 pr_warn("extern %s=%llu value doesn't fit in %d bytes\n",
1515                         ext->name, (unsigned long long)value, ext->sz);
1516                 return -ERANGE;
1517         }
1518         switch (ext->sz) {
1519                 case 1: *(__u8 *)ext_val = value; break;
1520                 case 2: *(__u16 *)ext_val = value; break;
1521                 case 4: *(__u32 *)ext_val = value; break;
1522                 case 8: *(__u64 *)ext_val = value; break;
1523                 default:
1524                         return -EINVAL;
1525         }
1526         ext->is_set = true;
1527         return 0;
1528 }
1529
1530 static int bpf_object__process_kconfig_line(struct bpf_object *obj,
1531                                             char *buf, void *data)
1532 {
1533         struct extern_desc *ext;
1534         char *sep, *value;
1535         int len, err = 0;
1536         void *ext_val;
1537         __u64 num;
1538
1539         if (strncmp(buf, "CONFIG_", 7))
1540                 return 0;
1541
1542         sep = strchr(buf, '=');
1543         if (!sep) {
1544                 pr_warn("failed to parse '%s': no separator\n", buf);
1545                 return -EINVAL;
1546         }
1547
1548         /* Trim ending '\n' */
1549         len = strlen(buf);
1550         if (buf[len - 1] == '\n')
1551                 buf[len - 1] = '\0';
1552         /* Split on '=' and ensure that a value is present. */
1553         *sep = '\0';
1554         if (!sep[1]) {
1555                 *sep = '=';
1556                 pr_warn("failed to parse '%s': no value\n", buf);
1557                 return -EINVAL;
1558         }
1559
1560         ext = find_extern_by_name(obj, buf);
1561         if (!ext || ext->is_set)
1562                 return 0;
1563
1564         ext_val = data + ext->data_off;
1565         value = sep + 1;
1566
1567         switch (*value) {
1568         case 'y': case 'n': case 'm':
1569                 err = set_ext_value_tri(ext, ext_val, *value);
1570                 break;
1571         case '"':
1572                 err = set_ext_value_str(ext, ext_val, value);
1573                 break;
1574         default:
1575                 /* assume integer */
1576                 err = parse_u64(value, &num);
1577                 if (err) {
1578                         pr_warn("extern %s=%s should be integer\n",
1579                                 ext->name, value);
1580                         return err;
1581                 }
1582                 err = set_ext_value_num(ext, ext_val, num);
1583                 break;
1584         }
1585         if (err)
1586                 return err;
1587         pr_debug("extern %s=%s\n", ext->name, value);
1588         return 0;
1589 }
1590
1591 static int bpf_object__read_kconfig_file(struct bpf_object *obj, void *data)
1592 {
1593         char buf[PATH_MAX];
1594         struct utsname uts;
1595         int len, err = 0;
1596         gzFile file;
1597
1598         uname(&uts);
1599         len = snprintf(buf, PATH_MAX, "/boot/config-%s", uts.release);
1600         if (len < 0)
1601                 return -EINVAL;
1602         else if (len >= PATH_MAX)
1603                 return -ENAMETOOLONG;
1604
1605         /* gzopen also accepts uncompressed files. */
1606         file = gzopen(buf, "r");
1607         if (!file)
1608                 file = gzopen("/proc/config.gz", "r");
1609
1610         if (!file) {
1611                 pr_warn("failed to open system Kconfig\n");
1612                 return -ENOENT;
1613         }
1614
1615         while (gzgets(file, buf, sizeof(buf))) {
1616                 err = bpf_object__process_kconfig_line(obj, buf, data);
1617                 if (err) {
1618                         pr_warn("error parsing system Kconfig line '%s': %d\n",
1619                                 buf, err);
1620                         goto out;
1621                 }
1622         }
1623
1624 out:
1625         gzclose(file);
1626         return err;
1627 }
1628
1629 static int bpf_object__read_kconfig_mem(struct bpf_object *obj,
1630                                         const char *config, void *data)
1631 {
1632         char buf[PATH_MAX];
1633         int err = 0;
1634         FILE *file;
1635
1636         file = fmemopen((void *)config, strlen(config), "r");
1637         if (!file) {
1638                 err = -errno;
1639                 pr_warn("failed to open in-memory Kconfig: %d\n", err);
1640                 return err;
1641         }
1642
1643         while (fgets(buf, sizeof(buf), file)) {
1644                 err = bpf_object__process_kconfig_line(obj, buf, data);
1645                 if (err) {
1646                         pr_warn("error parsing in-memory Kconfig line '%s': %d\n",
1647                                 buf, err);
1648                         break;
1649                 }
1650         }
1651
1652         fclose(file);
1653         return err;
1654 }
1655
1656 static int bpf_object__init_kconfig_map(struct bpf_object *obj)
1657 {
1658         struct extern_desc *last_ext;
1659         size_t map_sz;
1660         int err;
1661
1662         if (obj->nr_extern == 0)
1663                 return 0;
1664
1665         last_ext = &obj->externs[obj->nr_extern - 1];
1666         map_sz = last_ext->data_off + last_ext->sz;
1667
1668         err = bpf_object__init_internal_map(obj, LIBBPF_MAP_KCONFIG,
1669                                             obj->efile.symbols_shndx,
1670                                             NULL, map_sz);
1671         if (err)
1672                 return err;
1673
1674         obj->kconfig_map_idx = obj->nr_maps - 1;
1675
1676         return 0;
1677 }
1678
1679 static int bpf_object__init_user_maps(struct bpf_object *obj, bool strict)
1680 {
1681         Elf_Data *symbols = obj->efile.symbols;
1682         int i, map_def_sz = 0, nr_maps = 0, nr_syms;
1683         Elf_Data *data = NULL;
1684         Elf_Scn *scn;
1685
1686         if (obj->efile.maps_shndx < 0)
1687                 return 0;
1688
1689         if (!symbols)
1690                 return -EINVAL;
1691
1692         scn = elf_getscn(obj->efile.elf, obj->efile.maps_shndx);
1693         if (scn)
1694                 data = elf_getdata(scn, NULL);
1695         if (!scn || !data) {
1696                 pr_warn("failed to get Elf_Data from map section %d\n",
1697                         obj->efile.maps_shndx);
1698                 return -EINVAL;
1699         }
1700
1701         /*
1702          * Count number of maps. Each map has a name.
1703          * Array of maps is not supported: only the first element is
1704          * considered.
1705          *
1706          * TODO: Detect array of map and report error.
1707          */
1708         nr_syms = symbols->d_size / sizeof(GElf_Sym);
1709         for (i = 0; i < nr_syms; i++) {
1710                 GElf_Sym sym;
1711
1712                 if (!gelf_getsym(symbols, i, &sym))
1713                         continue;
1714                 if (sym.st_shndx != obj->efile.maps_shndx)
1715                         continue;
1716                 nr_maps++;
1717         }
1718         /* Assume equally sized map definitions */
1719         pr_debug("maps in %s: %d maps in %zd bytes\n",
1720                  obj->path, nr_maps, data->d_size);
1721
1722         if (!data->d_size || nr_maps == 0 || (data->d_size % nr_maps) != 0) {
1723                 pr_warn("unable to determine map definition size section %s, %d maps in %zd bytes\n",
1724                         obj->path, nr_maps, data->d_size);
1725                 return -EINVAL;
1726         }
1727         map_def_sz = data->d_size / nr_maps;
1728
1729         /* Fill obj->maps using data in "maps" section.  */
1730         for (i = 0; i < nr_syms; i++) {
1731                 GElf_Sym sym;
1732                 const char *map_name;
1733                 struct bpf_map_def *def;
1734                 struct bpf_map *map;
1735
1736                 if (!gelf_getsym(symbols, i, &sym))
1737                         continue;
1738                 if (sym.st_shndx != obj->efile.maps_shndx)
1739                         continue;
1740
1741                 map = bpf_object__add_map(obj);
1742                 if (IS_ERR(map))
1743                         return PTR_ERR(map);
1744
1745                 map_name = elf_strptr(obj->efile.elf, obj->efile.strtabidx,
1746                                       sym.st_name);
1747                 if (!map_name) {
1748                         pr_warn("failed to get map #%d name sym string for obj %s\n",
1749                                 i, obj->path);
1750                         return -LIBBPF_ERRNO__FORMAT;
1751                 }
1752
1753                 map->libbpf_type = LIBBPF_MAP_UNSPEC;
1754                 map->sec_idx = sym.st_shndx;
1755                 map->sec_offset = sym.st_value;
1756                 pr_debug("map '%s' (legacy): at sec_idx %d, offset %zu.\n",
1757                          map_name, map->sec_idx, map->sec_offset);
1758                 if (sym.st_value + map_def_sz > data->d_size) {
1759                         pr_warn("corrupted maps section in %s: last map \"%s\" too small\n",
1760                                 obj->path, map_name);
1761                         return -EINVAL;
1762                 }
1763
1764                 map->name = strdup(map_name);
1765                 if (!map->name) {
1766                         pr_warn("failed to alloc map name\n");
1767                         return -ENOMEM;
1768                 }
1769                 pr_debug("map %d is \"%s\"\n", i, map->name);
1770                 def = (struct bpf_map_def *)(data->d_buf + sym.st_value);
1771                 /*
1772                  * If the definition of the map in the object file fits in
1773                  * bpf_map_def, copy it.  Any extra fields in our version
1774                  * of bpf_map_def will default to zero as a result of the
1775                  * calloc above.
1776                  */
1777                 if (map_def_sz <= sizeof(struct bpf_map_def)) {
1778                         memcpy(&map->def, def, map_def_sz);
1779                 } else {
1780                         /*
1781                          * Here the map structure being read is bigger than what
1782                          * we expect, truncate if the excess bits are all zero.
1783                          * If they are not zero, reject this map as
1784                          * incompatible.
1785                          */
1786                         char *b;
1787
1788                         for (b = ((char *)def) + sizeof(struct bpf_map_def);
1789                              b < ((char *)def) + map_def_sz; b++) {
1790                                 if (*b != 0) {
1791                                         pr_warn("maps section in %s: \"%s\" has unrecognized, non-zero options\n",
1792                                                 obj->path, map_name);
1793                                         if (strict)
1794                                                 return -EINVAL;
1795                                 }
1796                         }
1797                         memcpy(&map->def, def, sizeof(struct bpf_map_def));
1798                 }
1799         }
1800         return 0;
1801 }
1802
1803 static const struct btf_type *
1804 skip_mods_and_typedefs(const struct btf *btf, __u32 id, __u32 *res_id)
1805 {
1806         const struct btf_type *t = btf__type_by_id(btf, id);
1807
1808         if (res_id)
1809                 *res_id = id;
1810
1811         while (btf_is_mod(t) || btf_is_typedef(t)) {
1812                 if (res_id)
1813                         *res_id = t->type;
1814                 t = btf__type_by_id(btf, t->type);
1815         }
1816
1817         return t;
1818 }
1819
1820 static const struct btf_type *
1821 resolve_func_ptr(const struct btf *btf, __u32 id, __u32 *res_id)
1822 {
1823         const struct btf_type *t;
1824
1825         t = skip_mods_and_typedefs(btf, id, NULL);
1826         if (!btf_is_ptr(t))
1827                 return NULL;
1828
1829         t = skip_mods_and_typedefs(btf, t->type, res_id);
1830
1831         return btf_is_func_proto(t) ? t : NULL;
1832 }
1833
1834 /*
1835  * Fetch integer attribute of BTF map definition. Such attributes are
1836  * represented using a pointer to an array, in which dimensionality of array
1837  * encodes specified integer value. E.g., int (*type)[BPF_MAP_TYPE_ARRAY];
1838  * encodes `type => BPF_MAP_TYPE_ARRAY` key/value pair completely using BTF
1839  * type definition, while using only sizeof(void *) space in ELF data section.
1840  */
1841 static bool get_map_field_int(const char *map_name, const struct btf *btf,
1842                               const struct btf_type *def,
1843                               const struct btf_member *m, __u32 *res)
1844 {
1845         const struct btf_type *t = skip_mods_and_typedefs(btf, m->type, NULL);
1846         const char *name = btf__name_by_offset(btf, m->name_off);
1847         const struct btf_array *arr_info;
1848         const struct btf_type *arr_t;
1849
1850         if (!btf_is_ptr(t)) {
1851                 pr_warn("map '%s': attr '%s': expected PTR, got %u.\n",
1852                         map_name, name, btf_kind(t));
1853                 return false;
1854         }
1855
1856         arr_t = btf__type_by_id(btf, t->type);
1857         if (!arr_t) {
1858                 pr_warn("map '%s': attr '%s': type [%u] not found.\n",
1859                         map_name, name, t->type);
1860                 return false;
1861         }
1862         if (!btf_is_array(arr_t)) {
1863                 pr_warn("map '%s': attr '%s': expected ARRAY, got %u.\n",
1864                         map_name, name, btf_kind(arr_t));
1865                 return false;
1866         }
1867         arr_info = btf_array(arr_t);
1868         *res = arr_info->nelems;
1869         return true;
1870 }
1871
1872 static int build_map_pin_path(struct bpf_map *map, const char *path)
1873 {
1874         char buf[PATH_MAX];
1875         int err, len;
1876
1877         if (!path)
1878                 path = "/sys/fs/bpf";
1879
1880         len = snprintf(buf, PATH_MAX, "%s/%s", path, bpf_map__name(map));
1881         if (len < 0)
1882                 return -EINVAL;
1883         else if (len >= PATH_MAX)
1884                 return -ENAMETOOLONG;
1885
1886         err = bpf_map__set_pin_path(map, buf);
1887         if (err)
1888                 return err;
1889
1890         return 0;
1891 }
1892
1893 static int bpf_object__init_user_btf_map(struct bpf_object *obj,
1894                                          const struct btf_type *sec,
1895                                          int var_idx, int sec_idx,
1896                                          const Elf_Data *data, bool strict,
1897                                          const char *pin_root_path)
1898 {
1899         const struct btf_type *var, *def, *t;
1900         const struct btf_var_secinfo *vi;
1901         const struct btf_var *var_extra;
1902         const struct btf_member *m;
1903         const char *map_name;
1904         struct bpf_map *map;
1905         int vlen, i;
1906
1907         vi = btf_var_secinfos(sec) + var_idx;
1908         var = btf__type_by_id(obj->btf, vi->type);
1909         var_extra = btf_var(var);
1910         map_name = btf__name_by_offset(obj->btf, var->name_off);
1911         vlen = btf_vlen(var);
1912
1913         if (map_name == NULL || map_name[0] == '\0') {
1914                 pr_warn("map #%d: empty name.\n", var_idx);
1915                 return -EINVAL;
1916         }
1917         if ((__u64)vi->offset + vi->size > data->d_size) {
1918                 pr_warn("map '%s' BTF data is corrupted.\n", map_name);
1919                 return -EINVAL;
1920         }
1921         if (!btf_is_var(var)) {
1922                 pr_warn("map '%s': unexpected var kind %u.\n",
1923                         map_name, btf_kind(var));
1924                 return -EINVAL;
1925         }
1926         if (var_extra->linkage != BTF_VAR_GLOBAL_ALLOCATED &&
1927             var_extra->linkage != BTF_VAR_STATIC) {
1928                 pr_warn("map '%s': unsupported var linkage %u.\n",
1929                         map_name, var_extra->linkage);
1930                 return -EOPNOTSUPP;
1931         }
1932
1933         def = skip_mods_and_typedefs(obj->btf, var->type, NULL);
1934         if (!btf_is_struct(def)) {
1935                 pr_warn("map '%s': unexpected def kind %u.\n",
1936                         map_name, btf_kind(var));
1937                 return -EINVAL;
1938         }
1939         if (def->size > vi->size) {
1940                 pr_warn("map '%s': invalid def size.\n", map_name);
1941                 return -EINVAL;
1942         }
1943
1944         map = bpf_object__add_map(obj);
1945         if (IS_ERR(map))
1946                 return PTR_ERR(map);
1947         map->name = strdup(map_name);
1948         if (!map->name) {
1949                 pr_warn("map '%s': failed to alloc map name.\n", map_name);
1950                 return -ENOMEM;
1951         }
1952         map->libbpf_type = LIBBPF_MAP_UNSPEC;
1953         map->def.type = BPF_MAP_TYPE_UNSPEC;
1954         map->sec_idx = sec_idx;
1955         map->sec_offset = vi->offset;
1956         pr_debug("map '%s': at sec_idx %d, offset %zu.\n",
1957                  map_name, map->sec_idx, map->sec_offset);
1958
1959         vlen = btf_vlen(def);
1960         m = btf_members(def);
1961         for (i = 0; i < vlen; i++, m++) {
1962                 const char *name = btf__name_by_offset(obj->btf, m->name_off);
1963
1964                 if (!name) {
1965                         pr_warn("map '%s': invalid field #%d.\n", map_name, i);
1966                         return -EINVAL;
1967                 }
1968                 if (strcmp(name, "type") == 0) {
1969                         if (!get_map_field_int(map_name, obj->btf, def, m,
1970                                                &map->def.type))
1971                                 return -EINVAL;
1972                         pr_debug("map '%s': found type = %u.\n",
1973                                  map_name, map->def.type);
1974                 } else if (strcmp(name, "max_entries") == 0) {
1975                         if (!get_map_field_int(map_name, obj->btf, def, m,
1976                                                &map->def.max_entries))
1977                                 return -EINVAL;
1978                         pr_debug("map '%s': found max_entries = %u.\n",
1979                                  map_name, map->def.max_entries);
1980                 } else if (strcmp(name, "map_flags") == 0) {
1981                         if (!get_map_field_int(map_name, obj->btf, def, m,
1982                                                &map->def.map_flags))
1983                                 return -EINVAL;
1984                         pr_debug("map '%s': found map_flags = %u.\n",
1985                                  map_name, map->def.map_flags);
1986                 } else if (strcmp(name, "key_size") == 0) {
1987                         __u32 sz;
1988
1989                         if (!get_map_field_int(map_name, obj->btf, def, m,
1990                                                &sz))
1991                                 return -EINVAL;
1992                         pr_debug("map '%s': found key_size = %u.\n",
1993                                  map_name, sz);
1994                         if (map->def.key_size && map->def.key_size != sz) {
1995                                 pr_warn("map '%s': conflicting key size %u != %u.\n",
1996                                         map_name, map->def.key_size, sz);
1997                                 return -EINVAL;
1998                         }
1999                         map->def.key_size = sz;
2000                 } else if (strcmp(name, "key") == 0) {
2001                         __s64 sz;
2002
2003                         t = btf__type_by_id(obj->btf, m->type);
2004                         if (!t) {
2005                                 pr_warn("map '%s': key type [%d] not found.\n",
2006                                         map_name, m->type);
2007                                 return -EINVAL;
2008                         }
2009                         if (!btf_is_ptr(t)) {
2010                                 pr_warn("map '%s': key spec is not PTR: %u.\n",
2011                                         map_name, btf_kind(t));
2012                                 return -EINVAL;
2013                         }
2014                         sz = btf__resolve_size(obj->btf, t->type);
2015                         if (sz < 0) {
2016                                 pr_warn("map '%s': can't determine key size for type [%u]: %zd.\n",
2017                                         map_name, t->type, (ssize_t)sz);
2018                                 return sz;
2019                         }
2020                         pr_debug("map '%s': found key [%u], sz = %zd.\n",
2021                                  map_name, t->type, (ssize_t)sz);
2022                         if (map->def.key_size && map->def.key_size != sz) {
2023                                 pr_warn("map '%s': conflicting key size %u != %zd.\n",
2024                                         map_name, map->def.key_size, (ssize_t)sz);
2025                                 return -EINVAL;
2026                         }
2027                         map->def.key_size = sz;
2028                         map->btf_key_type_id = t->type;
2029                 } else if (strcmp(name, "value_size") == 0) {
2030                         __u32 sz;
2031
2032                         if (!get_map_field_int(map_name, obj->btf, def, m,
2033                                                &sz))
2034                                 return -EINVAL;
2035                         pr_debug("map '%s': found value_size = %u.\n",
2036                                  map_name, sz);
2037                         if (map->def.value_size && map->def.value_size != sz) {
2038                                 pr_warn("map '%s': conflicting value size %u != %u.\n",
2039                                         map_name, map->def.value_size, sz);
2040                                 return -EINVAL;
2041                         }
2042                         map->def.value_size = sz;
2043                 } else if (strcmp(name, "value") == 0) {
2044                         __s64 sz;
2045
2046                         t = btf__type_by_id(obj->btf, m->type);
2047                         if (!t) {
2048                                 pr_warn("map '%s': value type [%d] not found.\n",
2049                                         map_name, m->type);
2050                                 return -EINVAL;
2051                         }
2052                         if (!btf_is_ptr(t)) {
2053                                 pr_warn("map '%s': value spec is not PTR: %u.\n",
2054                                         map_name, btf_kind(t));
2055                                 return -EINVAL;
2056                         }
2057                         sz = btf__resolve_size(obj->btf, t->type);
2058                         if (sz < 0) {
2059                                 pr_warn("map '%s': can't determine value size for type [%u]: %zd.\n",
2060                                         map_name, t->type, (ssize_t)sz);
2061                                 return sz;
2062                         }
2063                         pr_debug("map '%s': found value [%u], sz = %zd.\n",
2064                                  map_name, t->type, (ssize_t)sz);
2065                         if (map->def.value_size && map->def.value_size != sz) {
2066                                 pr_warn("map '%s': conflicting value size %u != %zd.\n",
2067                                         map_name, map->def.value_size, (ssize_t)sz);
2068                                 return -EINVAL;
2069                         }
2070                         map->def.value_size = sz;
2071                         map->btf_value_type_id = t->type;
2072                 } else if (strcmp(name, "pinning") == 0) {
2073                         __u32 val;
2074                         int err;
2075
2076                         if (!get_map_field_int(map_name, obj->btf, def, m,
2077                                                &val))
2078                                 return -EINVAL;
2079                         pr_debug("map '%s': found pinning = %u.\n",
2080                                  map_name, val);
2081
2082                         if (val != LIBBPF_PIN_NONE &&
2083                             val != LIBBPF_PIN_BY_NAME) {
2084                                 pr_warn("map '%s': invalid pinning value %u.\n",
2085                                         map_name, val);
2086                                 return -EINVAL;
2087                         }
2088                         if (val == LIBBPF_PIN_BY_NAME) {
2089                                 err = build_map_pin_path(map, pin_root_path);
2090                                 if (err) {
2091                                         pr_warn("map '%s': couldn't build pin path.\n",
2092                                                 map_name);
2093                                         return err;
2094                                 }
2095                         }
2096                 } else {
2097                         if (strict) {
2098                                 pr_warn("map '%s': unknown field '%s'.\n",
2099                                         map_name, name);
2100                                 return -ENOTSUP;
2101                         }
2102                         pr_debug("map '%s': ignoring unknown field '%s'.\n",
2103                                  map_name, name);
2104                 }
2105         }
2106
2107         if (map->def.type == BPF_MAP_TYPE_UNSPEC) {
2108                 pr_warn("map '%s': map type isn't specified.\n", map_name);
2109                 return -EINVAL;
2110         }
2111
2112         return 0;
2113 }
2114
2115 static int bpf_object__init_user_btf_maps(struct bpf_object *obj, bool strict,
2116                                           const char *pin_root_path)
2117 {
2118         const struct btf_type *sec = NULL;
2119         int nr_types, i, vlen, err;
2120         const struct btf_type *t;
2121         const char *name;
2122         Elf_Data *data;
2123         Elf_Scn *scn;
2124
2125         if (obj->efile.btf_maps_shndx < 0)
2126                 return 0;
2127
2128         scn = elf_getscn(obj->efile.elf, obj->efile.btf_maps_shndx);
2129         if (scn)
2130                 data = elf_getdata(scn, NULL);
2131         if (!scn || !data) {
2132                 pr_warn("failed to get Elf_Data from map section %d (%s)\n",
2133                         obj->efile.maps_shndx, MAPS_ELF_SEC);
2134                 return -EINVAL;
2135         }
2136
2137         nr_types = btf__get_nr_types(obj->btf);
2138         for (i = 1; i <= nr_types; i++) {
2139                 t = btf__type_by_id(obj->btf, i);
2140                 if (!btf_is_datasec(t))
2141                         continue;
2142                 name = btf__name_by_offset(obj->btf, t->name_off);
2143                 if (strcmp(name, MAPS_ELF_SEC) == 0) {
2144                         sec = t;
2145                         break;
2146                 }
2147         }
2148
2149         if (!sec) {
2150                 pr_warn("DATASEC '%s' not found.\n", MAPS_ELF_SEC);
2151                 return -ENOENT;
2152         }
2153
2154         vlen = btf_vlen(sec);
2155         for (i = 0; i < vlen; i++) {
2156                 err = bpf_object__init_user_btf_map(obj, sec, i,
2157                                                     obj->efile.btf_maps_shndx,
2158                                                     data, strict,
2159                                                     pin_root_path);
2160                 if (err)
2161                         return err;
2162         }
2163
2164         return 0;
2165 }
2166
2167 static int bpf_object__init_maps(struct bpf_object *obj,
2168                                  const struct bpf_object_open_opts *opts)
2169 {
2170         const char *pin_root_path;
2171         bool strict;
2172         int err;
2173
2174         strict = !OPTS_GET(opts, relaxed_maps, false);
2175         pin_root_path = OPTS_GET(opts, pin_root_path, NULL);
2176
2177         err = bpf_object__init_user_maps(obj, strict);
2178         err = err ?: bpf_object__init_user_btf_maps(obj, strict, pin_root_path);
2179         err = err ?: bpf_object__init_global_data_maps(obj);
2180         err = err ?: bpf_object__init_kconfig_map(obj);
2181         err = err ?: bpf_object__init_struct_ops_maps(obj);
2182         if (err)
2183                 return err;
2184
2185         return 0;
2186 }
2187
2188 static bool section_have_execinstr(struct bpf_object *obj, int idx)
2189 {
2190         Elf_Scn *scn;
2191         GElf_Shdr sh;
2192
2193         scn = elf_getscn(obj->efile.elf, idx);
2194         if (!scn)
2195                 return false;
2196
2197         if (gelf_getshdr(scn, &sh) != &sh)
2198                 return false;
2199
2200         if (sh.sh_flags & SHF_EXECINSTR)
2201                 return true;
2202
2203         return false;
2204 }
2205
2206 static void bpf_object__sanitize_btf(struct bpf_object *obj)
2207 {
2208         bool has_func_global = obj->caps.btf_func_global;
2209         bool has_datasec = obj->caps.btf_datasec;
2210         bool has_func = obj->caps.btf_func;
2211         struct btf *btf = obj->btf;
2212         struct btf_type *t;
2213         int i, j, vlen;
2214
2215         if (!obj->btf || (has_func && has_datasec && has_func_global))
2216                 return;
2217
2218         for (i = 1; i <= btf__get_nr_types(btf); i++) {
2219                 t = (struct btf_type *)btf__type_by_id(btf, i);
2220
2221                 if (!has_datasec && btf_is_var(t)) {
2222                         /* replace VAR with INT */
2223                         t->info = BTF_INFO_ENC(BTF_KIND_INT, 0, 0);
2224                         /*
2225                          * using size = 1 is the safest choice, 4 will be too
2226                          * big and cause kernel BTF validation failure if
2227                          * original variable took less than 4 bytes
2228                          */
2229                         t->size = 1;
2230                         *(int *)(t + 1) = BTF_INT_ENC(0, 0, 8);
2231                 } else if (!has_datasec && btf_is_datasec(t)) {
2232                         /* replace DATASEC with STRUCT */
2233                         const struct btf_var_secinfo *v = btf_var_secinfos(t);
2234                         struct btf_member *m = btf_members(t);
2235                         struct btf_type *vt;
2236                         char *name;
2237
2238                         name = (char *)btf__name_by_offset(btf, t->name_off);
2239                         while (*name) {
2240                                 if (*name == '.')
2241                                         *name = '_';
2242                                 name++;
2243                         }
2244
2245                         vlen = btf_vlen(t);
2246                         t->info = BTF_INFO_ENC(BTF_KIND_STRUCT, 0, vlen);
2247                         for (j = 0; j < vlen; j++, v++, m++) {
2248                                 /* order of field assignments is important */
2249                                 m->offset = v->offset * 8;
2250                                 m->type = v->type;
2251                                 /* preserve variable name as member name */
2252                                 vt = (void *)btf__type_by_id(btf, v->type);
2253                                 m->name_off = vt->name_off;
2254                         }
2255                 } else if (!has_func && btf_is_func_proto(t)) {
2256                         /* replace FUNC_PROTO with ENUM */
2257                         vlen = btf_vlen(t);
2258                         t->info = BTF_INFO_ENC(BTF_KIND_ENUM, 0, vlen);
2259                         t->size = sizeof(__u32); /* kernel enforced */
2260                 } else if (!has_func && btf_is_func(t)) {
2261                         /* replace FUNC with TYPEDEF */
2262                         t->info = BTF_INFO_ENC(BTF_KIND_TYPEDEF, 0, 0);
2263                 } else if (!has_func_global && btf_is_func(t)) {
2264                         /* replace BTF_FUNC_GLOBAL with BTF_FUNC_STATIC */
2265                         t->info = BTF_INFO_ENC(BTF_KIND_FUNC, 0, 0);
2266                 }
2267         }
2268 }
2269
2270 static void bpf_object__sanitize_btf_ext(struct bpf_object *obj)
2271 {
2272         if (!obj->btf_ext)
2273                 return;
2274
2275         if (!obj->caps.btf_func) {
2276                 btf_ext__free(obj->btf_ext);
2277                 obj->btf_ext = NULL;
2278         }
2279 }
2280
2281 static bool bpf_object__is_btf_mandatory(const struct bpf_object *obj)
2282 {
2283         return obj->efile.btf_maps_shndx >= 0 ||
2284                 obj->efile.st_ops_shndx >= 0 ||
2285                 obj->nr_extern > 0;
2286 }
2287
2288 static int bpf_object__init_btf(struct bpf_object *obj,
2289                                 Elf_Data *btf_data,
2290                                 Elf_Data *btf_ext_data)
2291 {
2292         int err = -ENOENT;
2293
2294         if (btf_data) {
2295                 obj->btf = btf__new(btf_data->d_buf, btf_data->d_size);
2296                 if (IS_ERR(obj->btf)) {
2297                         err = PTR_ERR(obj->btf);
2298                         obj->btf = NULL;
2299                         pr_warn("Error loading ELF section %s: %d.\n",
2300                                 BTF_ELF_SEC, err);
2301                         goto out;
2302                 }
2303                 err = 0;
2304         }
2305         if (btf_ext_data) {
2306                 if (!obj->btf) {
2307                         pr_debug("Ignore ELF section %s because its depending ELF section %s is not found.\n",
2308                                  BTF_EXT_ELF_SEC, BTF_ELF_SEC);
2309                         goto out;
2310                 }
2311                 obj->btf_ext = btf_ext__new(btf_ext_data->d_buf,
2312                                             btf_ext_data->d_size);
2313                 if (IS_ERR(obj->btf_ext)) {
2314                         pr_warn("Error loading ELF section %s: %ld. Ignored and continue.\n",
2315                                 BTF_EXT_ELF_SEC, PTR_ERR(obj->btf_ext));
2316                         obj->btf_ext = NULL;
2317                         goto out;
2318                 }
2319         }
2320 out:
2321         if (err && bpf_object__is_btf_mandatory(obj)) {
2322                 pr_warn("BTF is required, but is missing or corrupted.\n");
2323                 return err;
2324         }
2325         return 0;
2326 }
2327
2328 static int bpf_object__finalize_btf(struct bpf_object *obj)
2329 {
2330         int err;
2331
2332         if (!obj->btf)
2333                 return 0;
2334
2335         err = btf__finalize_data(obj, obj->btf);
2336         if (!err)
2337                 return 0;
2338
2339         pr_warn("Error finalizing %s: %d.\n", BTF_ELF_SEC, err);
2340         btf__free(obj->btf);
2341         obj->btf = NULL;
2342         btf_ext__free(obj->btf_ext);
2343         obj->btf_ext = NULL;
2344
2345         if (bpf_object__is_btf_mandatory(obj)) {
2346                 pr_warn("BTF is required, but is missing or corrupted.\n");
2347                 return -ENOENT;
2348         }
2349         return 0;
2350 }
2351
2352 static inline bool libbpf_prog_needs_vmlinux_btf(struct bpf_program *prog)
2353 {
2354         if (prog->type == BPF_PROG_TYPE_STRUCT_OPS)
2355                 return true;
2356
2357         /* BPF_PROG_TYPE_TRACING programs which do not attach to other programs
2358          * also need vmlinux BTF
2359          */
2360         if (prog->type == BPF_PROG_TYPE_TRACING && !prog->attach_prog_fd)
2361                 return true;
2362
2363         return false;
2364 }
2365
2366 static int bpf_object__load_vmlinux_btf(struct bpf_object *obj)
2367 {
2368         struct bpf_program *prog;
2369         int err;
2370
2371         bpf_object__for_each_program(prog, obj) {
2372                 if (libbpf_prog_needs_vmlinux_btf(prog)) {
2373                         obj->btf_vmlinux = libbpf_find_kernel_btf();
2374                         if (IS_ERR(obj->btf_vmlinux)) {
2375                                 err = PTR_ERR(obj->btf_vmlinux);
2376                                 pr_warn("Error loading vmlinux BTF: %d\n", err);
2377                                 obj->btf_vmlinux = NULL;
2378                                 return err;
2379                         }
2380                         return 0;
2381                 }
2382         }
2383
2384         return 0;
2385 }
2386
2387 static int bpf_object__sanitize_and_load_btf(struct bpf_object *obj)
2388 {
2389         int err = 0;
2390
2391         if (!obj->btf)
2392                 return 0;
2393
2394         bpf_object__sanitize_btf(obj);
2395         bpf_object__sanitize_btf_ext(obj);
2396
2397         err = btf__load(obj->btf);
2398         if (err) {
2399                 pr_warn("Error loading %s into kernel: %d.\n",
2400                         BTF_ELF_SEC, err);
2401                 btf__free(obj->btf);
2402                 obj->btf = NULL;
2403                 /* btf_ext can't exist without btf, so free it as well */
2404                 if (obj->btf_ext) {
2405                         btf_ext__free(obj->btf_ext);
2406                         obj->btf_ext = NULL;
2407                 }
2408
2409                 if (bpf_object__is_btf_mandatory(obj))
2410                         return err;
2411         }
2412         return 0;
2413 }
2414
2415 static int bpf_object__elf_collect(struct bpf_object *obj)
2416 {
2417         Elf *elf = obj->efile.elf;
2418         GElf_Ehdr *ep = &obj->efile.ehdr;
2419         Elf_Data *btf_ext_data = NULL;
2420         Elf_Data *btf_data = NULL;
2421         Elf_Scn *scn = NULL;
2422         int idx = 0, err = 0;
2423
2424         /* Elf is corrupted/truncated, avoid calling elf_strptr. */
2425         if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL)) {
2426                 pr_warn("failed to get e_shstrndx from %s\n", obj->path);
2427                 return -LIBBPF_ERRNO__FORMAT;
2428         }
2429
2430         while ((scn = elf_nextscn(elf, scn)) != NULL) {
2431                 char *name;
2432                 GElf_Shdr sh;
2433                 Elf_Data *data;
2434
2435                 idx++;
2436                 if (gelf_getshdr(scn, &sh) != &sh) {
2437                         pr_warn("failed to get section(%d) header from %s\n",
2438                                 idx, obj->path);
2439                         return -LIBBPF_ERRNO__FORMAT;
2440                 }
2441
2442                 name = elf_strptr(elf, ep->e_shstrndx, sh.sh_name);
2443                 if (!name) {
2444                         pr_warn("failed to get section(%d) name from %s\n",
2445                                 idx, obj->path);
2446                         return -LIBBPF_ERRNO__FORMAT;
2447                 }
2448
2449                 data = elf_getdata(scn, 0);
2450                 if (!data) {
2451                         pr_warn("failed to get section(%d) data from %s(%s)\n",
2452                                 idx, name, obj->path);
2453                         return -LIBBPF_ERRNO__FORMAT;
2454                 }
2455                 pr_debug("section(%d) %s, size %ld, link %d, flags %lx, type=%d\n",
2456                          idx, name, (unsigned long)data->d_size,
2457                          (int)sh.sh_link, (unsigned long)sh.sh_flags,
2458                          (int)sh.sh_type);
2459
2460                 if (strcmp(name, "license") == 0) {
2461                         err = bpf_object__init_license(obj,
2462                                                        data->d_buf,
2463                                                        data->d_size);
2464                         if (err)
2465                                 return err;
2466                 } else if (strcmp(name, "version") == 0) {
2467                         err = bpf_object__init_kversion(obj,
2468                                                         data->d_buf,
2469                                                         data->d_size);
2470                         if (err)
2471                                 return err;
2472                 } else if (strcmp(name, "maps") == 0) {
2473                         obj->efile.maps_shndx = idx;
2474                 } else if (strcmp(name, MAPS_ELF_SEC) == 0) {
2475                         obj->efile.btf_maps_shndx = idx;
2476                 } else if (strcmp(name, BTF_ELF_SEC) == 0) {
2477                         btf_data = data;
2478                 } else if (strcmp(name, BTF_EXT_ELF_SEC) == 0) {
2479                         btf_ext_data = data;
2480                 } else if (sh.sh_type == SHT_SYMTAB) {
2481                         if (obj->efile.symbols) {
2482                                 pr_warn("bpf: multiple SYMTAB in %s\n",
2483                                         obj->path);
2484                                 return -LIBBPF_ERRNO__FORMAT;
2485                         }
2486                         obj->efile.symbols = data;
2487                         obj->efile.symbols_shndx = idx;
2488                         obj->efile.strtabidx = sh.sh_link;
2489                 } else if (sh.sh_type == SHT_PROGBITS && data->d_size > 0) {
2490                         if (sh.sh_flags & SHF_EXECINSTR) {
2491                                 if (strcmp(name, ".text") == 0)
2492                                         obj->efile.text_shndx = idx;
2493                                 err = bpf_object__add_program(obj, data->d_buf,
2494                                                               data->d_size,
2495                                                               name, idx);
2496                                 if (err) {
2497                                         char errmsg[STRERR_BUFSIZE];
2498                                         char *cp;
2499
2500                                         cp = libbpf_strerror_r(-err, errmsg,
2501                                                                sizeof(errmsg));
2502                                         pr_warn("failed to alloc program %s (%s): %s",
2503                                                 name, obj->path, cp);
2504                                         return err;
2505                                 }
2506                         } else if (strcmp(name, DATA_SEC) == 0) {
2507                                 obj->efile.data = data;
2508                                 obj->efile.data_shndx = idx;
2509                         } else if (strcmp(name, RODATA_SEC) == 0) {
2510                                 obj->efile.rodata = data;
2511                                 obj->efile.rodata_shndx = idx;
2512                         } else if (strcmp(name, STRUCT_OPS_SEC) == 0) {
2513                                 obj->efile.st_ops_data = data;
2514                                 obj->efile.st_ops_shndx = idx;
2515                         } else {
2516                                 pr_debug("skip section(%d) %s\n", idx, name);
2517                         }
2518                 } else if (sh.sh_type == SHT_REL) {
2519                         int nr_sects = obj->efile.nr_reloc_sects;
2520                         void *sects = obj->efile.reloc_sects;
2521                         int sec = sh.sh_info; /* points to other section */
2522
2523                         /* Only do relo for section with exec instructions */
2524                         if (!section_have_execinstr(obj, sec) &&
2525                             strcmp(name, ".rel" STRUCT_OPS_SEC)) {
2526                                 pr_debug("skip relo %s(%d) for section(%d)\n",
2527                                          name, idx, sec);
2528                                 continue;
2529                         }
2530
2531                         sects = reallocarray(sects, nr_sects + 1,
2532                                              sizeof(*obj->efile.reloc_sects));
2533                         if (!sects) {
2534                                 pr_warn("reloc_sects realloc failed\n");
2535                                 return -ENOMEM;
2536                         }
2537
2538                         obj->efile.reloc_sects = sects;
2539                         obj->efile.nr_reloc_sects++;
2540
2541                         obj->efile.reloc_sects[nr_sects].shdr = sh;
2542                         obj->efile.reloc_sects[nr_sects].data = data;
2543                 } else if (sh.sh_type == SHT_NOBITS &&
2544                            strcmp(name, BSS_SEC) == 0) {
2545                         obj->efile.bss = data;
2546                         obj->efile.bss_shndx = idx;
2547                 } else {
2548                         pr_debug("skip section(%d) %s\n", idx, name);
2549                 }
2550         }
2551
2552         if (!obj->efile.strtabidx || obj->efile.strtabidx > idx) {
2553                 pr_warn("Corrupted ELF file: index of strtab invalid\n");
2554                 return -LIBBPF_ERRNO__FORMAT;
2555         }
2556         return bpf_object__init_btf(obj, btf_data, btf_ext_data);
2557 }
2558
2559 static bool sym_is_extern(const GElf_Sym *sym)
2560 {
2561         int bind = GELF_ST_BIND(sym->st_info);
2562         /* externs are symbols w/ type=NOTYPE, bind=GLOBAL|WEAK, section=UND */
2563         return sym->st_shndx == SHN_UNDEF &&
2564                (bind == STB_GLOBAL || bind == STB_WEAK) &&
2565                GELF_ST_TYPE(sym->st_info) == STT_NOTYPE;
2566 }
2567
2568 static int find_extern_btf_id(const struct btf *btf, const char *ext_name)
2569 {
2570         const struct btf_type *t;
2571         const char *var_name;
2572         int i, n;
2573
2574         if (!btf)
2575                 return -ESRCH;
2576
2577         n = btf__get_nr_types(btf);
2578         for (i = 1; i <= n; i++) {
2579                 t = btf__type_by_id(btf, i);
2580
2581                 if (!btf_is_var(t))
2582                         continue;
2583
2584                 var_name = btf__name_by_offset(btf, t->name_off);
2585                 if (strcmp(var_name, ext_name))
2586                         continue;
2587
2588                 if (btf_var(t)->linkage != BTF_VAR_GLOBAL_EXTERN)
2589                         return -EINVAL;
2590
2591                 return i;
2592         }
2593
2594         return -ENOENT;
2595 }
2596
2597 static enum extern_type find_extern_type(const struct btf *btf, int id,
2598                                          bool *is_signed)
2599 {
2600         const struct btf_type *t;
2601         const char *name;
2602
2603         t = skip_mods_and_typedefs(btf, id, NULL);
2604         name = btf__name_by_offset(btf, t->name_off);
2605
2606         if (is_signed)
2607                 *is_signed = false;
2608         switch (btf_kind(t)) {
2609         case BTF_KIND_INT: {
2610                 int enc = btf_int_encoding(t);
2611
2612                 if (enc & BTF_INT_BOOL)
2613                         return t->size == 1 ? EXT_BOOL : EXT_UNKNOWN;
2614                 if (is_signed)
2615                         *is_signed = enc & BTF_INT_SIGNED;
2616                 if (t->size == 1)
2617                         return EXT_CHAR;
2618                 if (t->size < 1 || t->size > 8 || (t->size & (t->size - 1)))
2619                         return EXT_UNKNOWN;
2620                 return EXT_INT;
2621         }
2622         case BTF_KIND_ENUM:
2623                 if (t->size != 4)
2624                         return EXT_UNKNOWN;
2625                 if (strcmp(name, "libbpf_tristate"))
2626                         return EXT_UNKNOWN;
2627                 return EXT_TRISTATE;
2628         case BTF_KIND_ARRAY:
2629                 if (btf_array(t)->nelems == 0)
2630                         return EXT_UNKNOWN;
2631                 if (find_extern_type(btf, btf_array(t)->type, NULL) != EXT_CHAR)
2632                         return EXT_UNKNOWN;
2633                 return EXT_CHAR_ARR;
2634         default:
2635                 return EXT_UNKNOWN;
2636         }
2637 }
2638
2639 static int cmp_externs(const void *_a, const void *_b)
2640 {
2641         const struct extern_desc *a = _a;
2642         const struct extern_desc *b = _b;
2643
2644         /* descending order by alignment requirements */
2645         if (a->align != b->align)
2646                 return a->align > b->align ? -1 : 1;
2647         /* ascending order by size, within same alignment class */
2648         if (a->sz != b->sz)
2649                 return a->sz < b->sz ? -1 : 1;
2650         /* resolve ties by name */
2651         return strcmp(a->name, b->name);
2652 }
2653
2654 static int bpf_object__collect_externs(struct bpf_object *obj)
2655 {
2656         const struct btf_type *t;
2657         struct extern_desc *ext;
2658         int i, n, off, btf_id;
2659         struct btf_type *sec;
2660         const char *ext_name;
2661         Elf_Scn *scn;
2662         GElf_Shdr sh;
2663
2664         if (!obj->efile.symbols)
2665                 return 0;
2666
2667         scn = elf_getscn(obj->efile.elf, obj->efile.symbols_shndx);
2668         if (!scn)
2669                 return -LIBBPF_ERRNO__FORMAT;
2670         if (gelf_getshdr(scn, &sh) != &sh)
2671                 return -LIBBPF_ERRNO__FORMAT;
2672         n = sh.sh_size / sh.sh_entsize;
2673
2674         pr_debug("looking for externs among %d symbols...\n", n);
2675         for (i = 0; i < n; i++) {
2676                 GElf_Sym sym;
2677
2678                 if (!gelf_getsym(obj->efile.symbols, i, &sym))
2679                         return -LIBBPF_ERRNO__FORMAT;
2680                 if (!sym_is_extern(&sym))
2681                         continue;
2682                 ext_name = elf_strptr(obj->efile.elf, obj->efile.strtabidx,
2683                                       sym.st_name);
2684                 if (!ext_name || !ext_name[0])
2685                         continue;
2686
2687                 ext = obj->externs;
2688                 ext = reallocarray(ext, obj->nr_extern + 1, sizeof(*ext));
2689                 if (!ext)
2690                         return -ENOMEM;
2691                 obj->externs = ext;
2692                 ext = &ext[obj->nr_extern];
2693                 memset(ext, 0, sizeof(*ext));
2694                 obj->nr_extern++;
2695
2696                 ext->btf_id = find_extern_btf_id(obj->btf, ext_name);
2697                 if (ext->btf_id <= 0) {
2698                         pr_warn("failed to find BTF for extern '%s': %d\n",
2699                                 ext_name, ext->btf_id);
2700                         return ext->btf_id;
2701                 }
2702                 t = btf__type_by_id(obj->btf, ext->btf_id);
2703                 ext->name = btf__name_by_offset(obj->btf, t->name_off);
2704                 ext->sym_idx = i;
2705                 ext->is_weak = GELF_ST_BIND(sym.st_info) == STB_WEAK;
2706                 ext->sz = btf__resolve_size(obj->btf, t->type);
2707                 if (ext->sz <= 0) {
2708                         pr_warn("failed to resolve size of extern '%s': %d\n",
2709                                 ext_name, ext->sz);
2710                         return ext->sz;
2711                 }
2712                 ext->align = btf__align_of(obj->btf, t->type);
2713                 if (ext->align <= 0) {
2714                         pr_warn("failed to determine alignment of extern '%s': %d\n",
2715                                 ext_name, ext->align);
2716                         return -EINVAL;
2717                 }
2718                 ext->type = find_extern_type(obj->btf, t->type,
2719                                              &ext->is_signed);
2720                 if (ext->type == EXT_UNKNOWN) {
2721                         pr_warn("extern '%s' type is unsupported\n", ext_name);
2722                         return -ENOTSUP;
2723                 }
2724         }
2725         pr_debug("collected %d externs total\n", obj->nr_extern);
2726
2727         if (!obj->nr_extern)
2728                 return 0;
2729
2730         /* sort externs by (alignment, size, name) and calculate their offsets
2731          * within a map */
2732         qsort(obj->externs, obj->nr_extern, sizeof(*ext), cmp_externs);
2733         off = 0;
2734         for (i = 0; i < obj->nr_extern; i++) {
2735                 ext = &obj->externs[i];
2736                 ext->data_off = roundup(off, ext->align);
2737                 off = ext->data_off + ext->sz;
2738                 pr_debug("extern #%d: symbol %d, off %u, name %s\n",
2739                          i, ext->sym_idx, ext->data_off, ext->name);
2740         }
2741
2742         btf_id = btf__find_by_name(obj->btf, KCONFIG_SEC);
2743         if (btf_id <= 0) {
2744                 pr_warn("no BTF info found for '%s' datasec\n", KCONFIG_SEC);
2745                 return -ESRCH;
2746         }
2747
2748         sec = (struct btf_type *)btf__type_by_id(obj->btf, btf_id);
2749         sec->size = off;
2750         n = btf_vlen(sec);
2751         for (i = 0; i < n; i++) {
2752                 struct btf_var_secinfo *vs = btf_var_secinfos(sec) + i;
2753
2754                 t = btf__type_by_id(obj->btf, vs->type);
2755                 ext_name = btf__name_by_offset(obj->btf, t->name_off);
2756                 ext = find_extern_by_name(obj, ext_name);
2757                 if (!ext) {
2758                         pr_warn("failed to find extern definition for BTF var '%s'\n",
2759                                 ext_name);
2760                         return -ESRCH;
2761                 }
2762                 vs->offset = ext->data_off;
2763                 btf_var(t)->linkage = BTF_VAR_GLOBAL_ALLOCATED;
2764         }
2765
2766         return 0;
2767 }
2768
2769 static struct bpf_program *
2770 bpf_object__find_prog_by_idx(struct bpf_object *obj, int idx)
2771 {
2772         struct bpf_program *prog;
2773         size_t i;
2774
2775         for (i = 0; i < obj->nr_programs; i++) {
2776                 prog = &obj->programs[i];
2777                 if (prog->idx == idx)
2778                         return prog;
2779         }
2780         return NULL;
2781 }
2782
2783 struct bpf_program *
2784 bpf_object__find_program_by_title(const struct bpf_object *obj,
2785                                   const char *title)
2786 {
2787         struct bpf_program *pos;
2788
2789         bpf_object__for_each_program(pos, obj) {
2790                 if (pos->section_name && !strcmp(pos->section_name, title))
2791                         return pos;
2792         }
2793         return NULL;
2794 }
2795
2796 struct bpf_program *
2797 bpf_object__find_program_by_name(const struct bpf_object *obj,
2798                                  const char *name)
2799 {
2800         struct bpf_program *prog;
2801
2802         bpf_object__for_each_program(prog, obj) {
2803                 if (!strcmp(prog->name, name))
2804                         return prog;
2805         }
2806         return NULL;
2807 }
2808
2809 static bool bpf_object__shndx_is_data(const struct bpf_object *obj,
2810                                       int shndx)
2811 {
2812         return shndx == obj->efile.data_shndx ||
2813                shndx == obj->efile.bss_shndx ||
2814                shndx == obj->efile.rodata_shndx;
2815 }
2816
2817 static bool bpf_object__shndx_is_maps(const struct bpf_object *obj,
2818                                       int shndx)
2819 {
2820         return shndx == obj->efile.maps_shndx ||
2821                shndx == obj->efile.btf_maps_shndx;
2822 }
2823
2824 static enum libbpf_map_type
2825 bpf_object__section_to_libbpf_map_type(const struct bpf_object *obj, int shndx)
2826 {
2827         if (shndx == obj->efile.data_shndx)
2828                 return LIBBPF_MAP_DATA;
2829         else if (shndx == obj->efile.bss_shndx)
2830                 return LIBBPF_MAP_BSS;
2831         else if (shndx == obj->efile.rodata_shndx)
2832                 return LIBBPF_MAP_RODATA;
2833         else if (shndx == obj->efile.symbols_shndx)
2834                 return LIBBPF_MAP_KCONFIG;
2835         else
2836                 return LIBBPF_MAP_UNSPEC;
2837 }
2838
2839 static int bpf_program__record_reloc(struct bpf_program *prog,
2840                                      struct reloc_desc *reloc_desc,
2841                                      __u32 insn_idx, const char *name,
2842                                      const GElf_Sym *sym, const GElf_Rel *rel)
2843 {
2844         struct bpf_insn *insn = &prog->insns[insn_idx];
2845         size_t map_idx, nr_maps = prog->obj->nr_maps;
2846         struct bpf_object *obj = prog->obj;
2847         __u32 shdr_idx = sym->st_shndx;
2848         enum libbpf_map_type type;
2849         struct bpf_map *map;
2850
2851         /* sub-program call relocation */
2852         if (insn->code == (BPF_JMP | BPF_CALL)) {
2853                 if (insn->src_reg != BPF_PSEUDO_CALL) {
2854                         pr_warn("incorrect bpf_call opcode\n");
2855                         return -LIBBPF_ERRNO__RELOC;
2856                 }
2857                 /* text_shndx can be 0, if no default "main" program exists */
2858                 if (!shdr_idx || shdr_idx != obj->efile.text_shndx) {
2859                         pr_warn("bad call relo against section %u\n", shdr_idx);
2860                         return -LIBBPF_ERRNO__RELOC;
2861                 }
2862                 if (sym->st_value % 8) {
2863                         pr_warn("bad call relo offset: %zu\n",
2864                                 (size_t)sym->st_value);
2865                         return -LIBBPF_ERRNO__RELOC;
2866                 }
2867                 reloc_desc->type = RELO_CALL;
2868                 reloc_desc->insn_idx = insn_idx;
2869                 reloc_desc->sym_off = sym->st_value;
2870                 obj->has_pseudo_calls = true;
2871                 return 0;
2872         }
2873
2874         if (insn->code != (BPF_LD | BPF_IMM | BPF_DW)) {
2875                 pr_warn("invalid relo for insns[%d].code 0x%x\n",
2876                         insn_idx, insn->code);
2877                 return -LIBBPF_ERRNO__RELOC;
2878         }
2879
2880         if (sym_is_extern(sym)) {
2881                 int sym_idx = GELF_R_SYM(rel->r_info);
2882                 int i, n = obj->nr_extern;
2883                 struct extern_desc *ext;
2884
2885                 for (i = 0; i < n; i++) {
2886                         ext = &obj->externs[i];
2887                         if (ext->sym_idx == sym_idx)
2888                                 break;
2889                 }
2890                 if (i >= n) {
2891                         pr_warn("extern relo failed to find extern for sym %d\n",
2892                                 sym_idx);
2893                         return -LIBBPF_ERRNO__RELOC;
2894                 }
2895                 pr_debug("found extern #%d '%s' (sym %d, off %u) for insn %u\n",
2896                          i, ext->name, ext->sym_idx, ext->data_off, insn_idx);
2897                 reloc_desc->type = RELO_EXTERN;
2898                 reloc_desc->insn_idx = insn_idx;
2899                 reloc_desc->sym_off = ext->data_off;
2900                 return 0;
2901         }
2902
2903         if (!shdr_idx || shdr_idx >= SHN_LORESERVE) {
2904                 pr_warn("invalid relo for \'%s\' in special section 0x%x; forgot to initialize global var?..\n",
2905                         name, shdr_idx);
2906                 return -LIBBPF_ERRNO__RELOC;
2907         }
2908
2909         type = bpf_object__section_to_libbpf_map_type(obj, shdr_idx);
2910
2911         /* generic map reference relocation */
2912         if (type == LIBBPF_MAP_UNSPEC) {
2913                 if (!bpf_object__shndx_is_maps(obj, shdr_idx)) {
2914                         pr_warn("bad map relo against section %u\n",
2915                                 shdr_idx);
2916                         return -LIBBPF_ERRNO__RELOC;
2917                 }
2918                 for (map_idx = 0; map_idx < nr_maps; map_idx++) {
2919                         map = &obj->maps[map_idx];
2920                         if (map->libbpf_type != type ||
2921                             map->sec_idx != sym->st_shndx ||
2922                             map->sec_offset != sym->st_value)
2923                                 continue;
2924                         pr_debug("found map %zd (%s, sec %d, off %zu) for insn %u\n",
2925                                  map_idx, map->name, map->sec_idx,
2926                                  map->sec_offset, insn_idx);
2927                         break;
2928                 }
2929                 if (map_idx >= nr_maps) {
2930                         pr_warn("map relo failed to find map for sec %u, off %zu\n",
2931                                 shdr_idx, (size_t)sym->st_value);
2932                         return -LIBBPF_ERRNO__RELOC;
2933                 }
2934                 reloc_desc->type = RELO_LD64;
2935                 reloc_desc->insn_idx = insn_idx;
2936                 reloc_desc->map_idx = map_idx;
2937                 reloc_desc->sym_off = 0; /* sym->st_value determines map_idx */
2938                 return 0;
2939         }
2940
2941         /* global data map relocation */
2942         if (!bpf_object__shndx_is_data(obj, shdr_idx)) {
2943                 pr_warn("bad data relo against section %u\n", shdr_idx);
2944                 return -LIBBPF_ERRNO__RELOC;
2945         }
2946         for (map_idx = 0; map_idx < nr_maps; map_idx++) {
2947                 map = &obj->maps[map_idx];
2948                 if (map->libbpf_type != type)
2949                         continue;
2950                 pr_debug("found data map %zd (%s, sec %d, off %zu) for insn %u\n",
2951                          map_idx, map->name, map->sec_idx, map->sec_offset,
2952                          insn_idx);
2953                 break;
2954         }
2955         if (map_idx >= nr_maps) {
2956                 pr_warn("data relo failed to find map for sec %u\n",
2957                         shdr_idx);
2958                 return -LIBBPF_ERRNO__RELOC;
2959         }
2960
2961         reloc_desc->type = RELO_DATA;
2962         reloc_desc->insn_idx = insn_idx;
2963         reloc_desc->map_idx = map_idx;
2964         reloc_desc->sym_off = sym->st_value;
2965         return 0;
2966 }
2967
2968 static int
2969 bpf_program__collect_reloc(struct bpf_program *prog, GElf_Shdr *shdr,
2970                            Elf_Data *data, struct bpf_object *obj)
2971 {
2972         Elf_Data *symbols = obj->efile.symbols;
2973         int err, i, nrels;
2974
2975         pr_debug("collecting relocating info for: '%s'\n", prog->section_name);
2976         nrels = shdr->sh_size / shdr->sh_entsize;
2977
2978         prog->reloc_desc = malloc(sizeof(*prog->reloc_desc) * nrels);
2979         if (!prog->reloc_desc) {
2980                 pr_warn("failed to alloc memory in relocation\n");
2981                 return -ENOMEM;
2982         }
2983         prog->nr_reloc = nrels;
2984
2985         for (i = 0; i < nrels; i++) {
2986                 const char *name;
2987                 __u32 insn_idx;
2988                 GElf_Sym sym;
2989                 GElf_Rel rel;
2990
2991                 if (!gelf_getrel(data, i, &rel)) {
2992                         pr_warn("relocation: failed to get %d reloc\n", i);
2993                         return -LIBBPF_ERRNO__FORMAT;
2994                 }
2995                 if (!gelf_getsym(symbols, GELF_R_SYM(rel.r_info), &sym)) {
2996                         pr_warn("relocation: symbol %"PRIx64" not found\n",
2997                                 GELF_R_SYM(rel.r_info));
2998                         return -LIBBPF_ERRNO__FORMAT;
2999                 }
3000                 if (rel.r_offset % sizeof(struct bpf_insn))
3001                         return -LIBBPF_ERRNO__FORMAT;
3002
3003                 insn_idx = rel.r_offset / sizeof(struct bpf_insn);
3004                 name = elf_strptr(obj->efile.elf, obj->efile.strtabidx,
3005                                   sym.st_name) ? : "<?>";
3006
3007                 pr_debug("relo for shdr %u, symb %zu, value %zu, type %d, bind %d, name %d (\'%s\'), insn %u\n",
3008                          (__u32)sym.st_shndx, (size_t)GELF_R_SYM(rel.r_info),
3009                          (size_t)sym.st_value, GELF_ST_TYPE(sym.st_info),
3010                          GELF_ST_BIND(sym.st_info), sym.st_name, name,
3011                          insn_idx);
3012
3013                 err = bpf_program__record_reloc(prog, &prog->reloc_desc[i],
3014                                                 insn_idx, name, &sym, &rel);
3015                 if (err)
3016                         return err;
3017         }
3018         return 0;
3019 }
3020
3021 static int bpf_map_find_btf_info(struct bpf_object *obj, struct bpf_map *map)
3022 {
3023         struct bpf_map_def *def = &map->def;
3024         __u32 key_type_id = 0, value_type_id = 0;
3025         int ret;
3026
3027         /* if it's BTF-defined map, we don't need to search for type IDs.
3028          * For struct_ops map, it does not need btf_key_type_id and
3029          * btf_value_type_id.
3030          */
3031         if (map->sec_idx == obj->efile.btf_maps_shndx ||
3032             bpf_map__is_struct_ops(map))
3033                 return 0;
3034
3035         if (!bpf_map__is_internal(map)) {
3036                 ret = btf__get_map_kv_tids(obj->btf, map->name, def->key_size,
3037                                            def->value_size, &key_type_id,
3038                                            &value_type_id);
3039         } else {
3040                 /*
3041                  * LLVM annotates global data differently in BTF, that is,
3042                  * only as '.data', '.bss' or '.rodata'.
3043                  */
3044                 ret = btf__find_by_name(obj->btf,
3045                                 libbpf_type_to_btf_name[map->libbpf_type]);
3046         }
3047         if (ret < 0)
3048                 return ret;
3049
3050         map->btf_key_type_id = key_type_id;
3051         map->btf_value_type_id = bpf_map__is_internal(map) ?
3052                                  ret : value_type_id;
3053         return 0;
3054 }
3055
3056 int bpf_map__reuse_fd(struct bpf_map *map, int fd)
3057 {
3058         struct bpf_map_info info = {};
3059         __u32 len = sizeof(info);
3060         int new_fd, err;
3061         char *new_name;
3062
3063         err = bpf_obj_get_info_by_fd(fd, &info, &len);
3064         if (err)
3065                 return err;
3066
3067         new_name = strdup(info.name);
3068         if (!new_name)
3069                 return -errno;
3070
3071         new_fd = open("/", O_RDONLY | O_CLOEXEC);
3072         if (new_fd < 0) {
3073                 err = -errno;
3074                 goto err_free_new_name;
3075         }
3076
3077         new_fd = dup3(fd, new_fd, O_CLOEXEC);
3078         if (new_fd < 0) {
3079                 err = -errno;
3080                 goto err_close_new_fd;
3081         }
3082
3083         err = zclose(map->fd);
3084         if (err) {
3085                 err = -errno;
3086                 goto err_close_new_fd;
3087         }
3088         free(map->name);
3089
3090         map->fd = new_fd;
3091         map->name = new_name;
3092         map->def.type = info.type;
3093         map->def.key_size = info.key_size;
3094         map->def.value_size = info.value_size;
3095         map->def.max_entries = info.max_entries;
3096         map->def.map_flags = info.map_flags;
3097         map->btf_key_type_id = info.btf_key_type_id;
3098         map->btf_value_type_id = info.btf_value_type_id;
3099         map->reused = true;
3100
3101         return 0;
3102
3103 err_close_new_fd:
3104         close(new_fd);
3105 err_free_new_name:
3106         free(new_name);
3107         return err;
3108 }
3109
3110 int bpf_map__resize(struct bpf_map *map, __u32 max_entries)
3111 {
3112         if (!map || !max_entries)
3113                 return -EINVAL;
3114
3115         /* If map already created, its attributes can't be changed. */
3116         if (map->fd >= 0)
3117                 return -EBUSY;
3118
3119         map->def.max_entries = max_entries;
3120
3121         return 0;
3122 }
3123
3124 static int
3125 bpf_object__probe_name(struct bpf_object *obj)
3126 {
3127         struct bpf_load_program_attr attr;
3128         char *cp, errmsg[STRERR_BUFSIZE];
3129         struct bpf_insn insns[] = {
3130                 BPF_MOV64_IMM(BPF_REG_0, 0),
3131                 BPF_EXIT_INSN(),
3132         };
3133         int ret;
3134
3135         /* make sure basic loading works */
3136
3137         memset(&attr, 0, sizeof(attr));
3138         attr.prog_type = BPF_PROG_TYPE_SOCKET_FILTER;
3139         attr.insns = insns;
3140         attr.insns_cnt = ARRAY_SIZE(insns);
3141         attr.license = "GPL";
3142
3143         ret = bpf_load_program_xattr(&attr, NULL, 0);
3144         if (ret < 0) {
3145                 cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg));
3146                 pr_warn("Error in %s():%s(%d). Couldn't load basic 'r0 = 0' BPF program.\n",
3147                         __func__, cp, errno);
3148                 return -errno;
3149         }
3150         close(ret);
3151
3152         /* now try the same program, but with the name */
3153
3154         attr.name = "test";
3155         ret = bpf_load_program_xattr(&attr, NULL, 0);
3156         if (ret >= 0) {
3157                 obj->caps.name = 1;
3158                 close(ret);
3159         }
3160
3161         return 0;
3162 }
3163
3164 static int
3165 bpf_object__probe_global_data(struct bpf_object *obj)
3166 {
3167         struct bpf_load_program_attr prg_attr;
3168         struct bpf_create_map_attr map_attr;
3169         char *cp, errmsg[STRERR_BUFSIZE];
3170         struct bpf_insn insns[] = {
3171                 BPF_LD_MAP_VALUE(BPF_REG_1, 0, 16),
3172                 BPF_ST_MEM(BPF_DW, BPF_REG_1, 0, 42),
3173                 BPF_MOV64_IMM(BPF_REG_0, 0),
3174                 BPF_EXIT_INSN(),
3175         };
3176         int ret, map;
3177
3178         memset(&map_attr, 0, sizeof(map_attr));
3179         map_attr.map_type = BPF_MAP_TYPE_ARRAY;
3180         map_attr.key_size = sizeof(int);
3181         map_attr.value_size = 32;
3182         map_attr.max_entries = 1;
3183
3184         map = bpf_create_map_xattr(&map_attr);
3185         if (map < 0) {
3186                 cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg));
3187                 pr_warn("Error in %s():%s(%d). Couldn't create simple array map.\n",
3188                         __func__, cp, errno);
3189                 return -errno;
3190         }
3191
3192         insns[0].imm = map;
3193
3194         memset(&prg_attr, 0, sizeof(prg_attr));
3195         prg_attr.prog_type = BPF_PROG_TYPE_SOCKET_FILTER;
3196         prg_attr.insns = insns;
3197         prg_attr.insns_cnt = ARRAY_SIZE(insns);
3198         prg_attr.license = "GPL";
3199
3200         ret = bpf_load_program_xattr(&prg_attr, NULL, 0);
3201         if (ret >= 0) {
3202                 obj->caps.global_data = 1;
3203                 close(ret);
3204         }
3205
3206         close(map);
3207         return 0;
3208 }
3209
3210 static int bpf_object__probe_btf_func(struct bpf_object *obj)
3211 {
3212         static const char strs[] = "\0int\0x\0a";
3213         /* void x(int a) {} */
3214         __u32 types[] = {
3215                 /* int */
3216                 BTF_TYPE_INT_ENC(1, BTF_INT_SIGNED, 0, 32, 4),  /* [1] */
3217                 /* FUNC_PROTO */                                /* [2] */
3218                 BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_FUNC_PROTO, 0, 1), 0),
3219                 BTF_PARAM_ENC(7, 1),
3220                 /* FUNC x */                                    /* [3] */
3221                 BTF_TYPE_ENC(5, BTF_INFO_ENC(BTF_KIND_FUNC, 0, 0), 2),
3222         };
3223         int btf_fd;
3224
3225         btf_fd = libbpf__load_raw_btf((char *)types, sizeof(types),
3226                                       strs, sizeof(strs));
3227         if (btf_fd >= 0) {
3228                 obj->caps.btf_func = 1;
3229                 close(btf_fd);
3230                 return 1;
3231         }
3232
3233         return 0;
3234 }
3235
3236 static int bpf_object__probe_btf_func_global(struct bpf_object *obj)
3237 {
3238         static const char strs[] = "\0int\0x\0a";
3239         /* static void x(int a) {} */
3240         __u32 types[] = {
3241                 /* int */
3242                 BTF_TYPE_INT_ENC(1, BTF_INT_SIGNED, 0, 32, 4),  /* [1] */
3243                 /* FUNC_PROTO */                                /* [2] */
3244                 BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_FUNC_PROTO, 0, 1), 0),
3245                 BTF_PARAM_ENC(7, 1),
3246                 /* FUNC x BTF_FUNC_GLOBAL */                    /* [3] */
3247                 BTF_TYPE_ENC(5, BTF_INFO_ENC(BTF_KIND_FUNC, 0, BTF_FUNC_GLOBAL), 2),
3248         };
3249         int btf_fd;
3250
3251         btf_fd = libbpf__load_raw_btf((char *)types, sizeof(types),
3252                                       strs, sizeof(strs));
3253         if (btf_fd >= 0) {
3254                 obj->caps.btf_func_global = 1;
3255                 close(btf_fd);
3256                 return 1;
3257         }
3258
3259         return 0;
3260 }
3261
3262 static int bpf_object__probe_btf_datasec(struct bpf_object *obj)
3263 {
3264         static const char strs[] = "\0x\0.data";
3265         /* static int a; */
3266         __u32 types[] = {
3267                 /* int */
3268                 BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4),  /* [1] */
3269                 /* VAR x */                                     /* [2] */
3270                 BTF_TYPE_ENC(1, BTF_INFO_ENC(BTF_KIND_VAR, 0, 0), 1),
3271                 BTF_VAR_STATIC,
3272                 /* DATASEC val */                               /* [3] */
3273                 BTF_TYPE_ENC(3, BTF_INFO_ENC(BTF_KIND_DATASEC, 0, 1), 4),
3274                 BTF_VAR_SECINFO_ENC(2, 0, 4),
3275         };
3276         int btf_fd;
3277
3278         btf_fd = libbpf__load_raw_btf((char *)types, sizeof(types),
3279                                       strs, sizeof(strs));
3280         if (btf_fd >= 0) {
3281                 obj->caps.btf_datasec = 1;
3282                 close(btf_fd);
3283                 return 1;
3284         }
3285
3286         return 0;
3287 }
3288
3289 static int bpf_object__probe_array_mmap(struct bpf_object *obj)
3290 {
3291         struct bpf_create_map_attr attr = {
3292                 .map_type = BPF_MAP_TYPE_ARRAY,
3293                 .map_flags = BPF_F_MMAPABLE,
3294                 .key_size = sizeof(int),
3295                 .value_size = sizeof(int),
3296                 .max_entries = 1,
3297         };
3298         int fd;
3299
3300         fd = bpf_create_map_xattr(&attr);
3301         if (fd >= 0) {
3302                 obj->caps.array_mmap = 1;
3303                 close(fd);
3304                 return 1;
3305         }
3306
3307         return 0;
3308 }
3309
3310 static int
3311 bpf_object__probe_caps(struct bpf_object *obj)
3312 {
3313         int (*probe_fn[])(struct bpf_object *obj) = {
3314                 bpf_object__probe_name,
3315                 bpf_object__probe_global_data,
3316                 bpf_object__probe_btf_func,
3317                 bpf_object__probe_btf_func_global,
3318                 bpf_object__probe_btf_datasec,
3319                 bpf_object__probe_array_mmap,
3320         };
3321         int i, ret;
3322
3323         for (i = 0; i < ARRAY_SIZE(probe_fn); i++) {
3324                 ret = probe_fn[i](obj);
3325                 if (ret < 0)
3326                         pr_debug("Probe #%d failed with %d.\n", i, ret);
3327         }
3328
3329         return 0;
3330 }
3331
3332 static bool map_is_reuse_compat(const struct bpf_map *map, int map_fd)
3333 {
3334         struct bpf_map_info map_info = {};
3335         char msg[STRERR_BUFSIZE];
3336         __u32 map_info_len;
3337
3338         map_info_len = sizeof(map_info);
3339
3340         if (bpf_obj_get_info_by_fd(map_fd, &map_info, &map_info_len)) {
3341                 pr_warn("failed to get map info for map FD %d: %s\n",
3342                         map_fd, libbpf_strerror_r(errno, msg, sizeof(msg)));
3343                 return false;
3344         }
3345
3346         return (map_info.type == map->def.type &&
3347                 map_info.key_size == map->def.key_size &&
3348                 map_info.value_size == map->def.value_size &&
3349                 map_info.max_entries == map->def.max_entries &&
3350                 map_info.map_flags == map->def.map_flags);
3351 }
3352
3353 static int
3354 bpf_object__reuse_map(struct bpf_map *map)
3355 {
3356         char *cp, errmsg[STRERR_BUFSIZE];
3357         int err, pin_fd;
3358
3359         pin_fd = bpf_obj_get(map->pin_path);
3360         if (pin_fd < 0) {
3361                 err = -errno;
3362                 if (err == -ENOENT) {
3363                         pr_debug("found no pinned map to reuse at '%s'\n",
3364                                  map->pin_path);
3365                         return 0;
3366                 }
3367
3368                 cp = libbpf_strerror_r(-err, errmsg, sizeof(errmsg));
3369                 pr_warn("couldn't retrieve pinned map '%s': %s\n",
3370                         map->pin_path, cp);
3371                 return err;
3372         }
3373
3374         if (!map_is_reuse_compat(map, pin_fd)) {
3375                 pr_warn("couldn't reuse pinned map at '%s': parameter mismatch\n",
3376                         map->pin_path);
3377                 close(pin_fd);
3378                 return -EINVAL;
3379         }
3380
3381         err = bpf_map__reuse_fd(map, pin_fd);
3382         if (err) {
3383                 close(pin_fd);
3384                 return err;
3385         }
3386         map->pinned = true;
3387         pr_debug("reused pinned map at '%s'\n", map->pin_path);
3388
3389         return 0;
3390 }
3391
3392 static int
3393 bpf_object__populate_internal_map(struct bpf_object *obj, struct bpf_map *map)
3394 {
3395         enum libbpf_map_type map_type = map->libbpf_type;
3396         char *cp, errmsg[STRERR_BUFSIZE];
3397         int err, zero = 0;
3398
3399         /* kernel already zero-initializes .bss map. */
3400         if (map_type == LIBBPF_MAP_BSS)
3401                 return 0;
3402
3403         err = bpf_map_update_elem(map->fd, &zero, map->mmaped, 0);
3404         if (err) {
3405                 err = -errno;
3406                 cp = libbpf_strerror_r(err, errmsg, sizeof(errmsg));
3407                 pr_warn("Error setting initial map(%s) contents: %s\n",
3408                         map->name, cp);
3409                 return err;
3410         }
3411
3412         /* Freeze .rodata and .kconfig map as read-only from syscall side. */
3413         if (map_type == LIBBPF_MAP_RODATA || map_type == LIBBPF_MAP_KCONFIG) {
3414                 err = bpf_map_freeze(map->fd);
3415                 if (err) {
3416                         err = -errno;
3417                         cp = libbpf_strerror_r(err, errmsg, sizeof(errmsg));
3418                         pr_warn("Error freezing map(%s) as read-only: %s\n",
3419                                 map->name, cp);
3420                         return err;
3421                 }
3422         }
3423         return 0;
3424 }
3425
3426 static int
3427 bpf_object__create_maps(struct bpf_object *obj)
3428 {
3429         struct bpf_create_map_attr create_attr = {};
3430         int nr_cpus = 0;
3431         unsigned int i;
3432         int err;
3433
3434         for (i = 0; i < obj->nr_maps; i++) {
3435                 struct bpf_map *map = &obj->maps[i];
3436                 struct bpf_map_def *def = &map->def;
3437                 char *cp, errmsg[STRERR_BUFSIZE];
3438                 int *pfd = &map->fd;
3439
3440                 if (map->pin_path) {
3441                         err = bpf_object__reuse_map(map);
3442                         if (err) {
3443                                 pr_warn("error reusing pinned map %s\n",
3444                                         map->name);
3445                                 return err;
3446                         }
3447                 }
3448
3449                 if (map->fd >= 0) {
3450                         pr_debug("skip map create (preset) %s: fd=%d\n",
3451                                  map->name, map->fd);
3452                         continue;
3453                 }
3454
3455                 if (obj->caps.name)
3456                         create_attr.name = map->name;
3457                 create_attr.map_ifindex = map->map_ifindex;
3458                 create_attr.map_type = def->type;
3459                 create_attr.map_flags = def->map_flags;
3460                 create_attr.key_size = def->key_size;
3461                 create_attr.value_size = def->value_size;
3462                 if (def->type == BPF_MAP_TYPE_PERF_EVENT_ARRAY &&
3463                     !def->max_entries) {
3464                         if (!nr_cpus)
3465                                 nr_cpus = libbpf_num_possible_cpus();
3466                         if (nr_cpus < 0) {
3467                                 pr_warn("failed to determine number of system CPUs: %d\n",
3468                                         nr_cpus);
3469                                 err = nr_cpus;
3470                                 goto err_out;
3471                         }
3472                         pr_debug("map '%s': setting size to %d\n",
3473                                  map->name, nr_cpus);
3474                         create_attr.max_entries = nr_cpus;
3475                 } else {
3476                         create_attr.max_entries = def->max_entries;
3477                 }
3478                 create_attr.btf_fd = 0;
3479                 create_attr.btf_key_type_id = 0;
3480                 create_attr.btf_value_type_id = 0;
3481                 if (bpf_map_type__is_map_in_map(def->type) &&
3482                     map->inner_map_fd >= 0)
3483                         create_attr.inner_map_fd = map->inner_map_fd;
3484                 if (bpf_map__is_struct_ops(map))
3485                         create_attr.btf_vmlinux_value_type_id =
3486                                 map->btf_vmlinux_value_type_id;
3487
3488                 if (obj->btf && !bpf_map_find_btf_info(obj, map)) {
3489                         create_attr.btf_fd = btf__fd(obj->btf);
3490                         create_attr.btf_key_type_id = map->btf_key_type_id;
3491                         create_attr.btf_value_type_id = map->btf_value_type_id;
3492                 }
3493
3494                 *pfd = bpf_create_map_xattr(&create_attr);
3495                 if (*pfd < 0 && (create_attr.btf_key_type_id ||
3496                                  create_attr.btf_value_type_id)) {
3497                         err = -errno;
3498                         cp = libbpf_strerror_r(err, errmsg, sizeof(errmsg));
3499                         pr_warn("Error in bpf_create_map_xattr(%s):%s(%d). Retrying without BTF.\n",
3500                                 map->name, cp, err);
3501                         create_attr.btf_fd = 0;
3502                         create_attr.btf_key_type_id = 0;
3503                         create_attr.btf_value_type_id = 0;
3504                         map->btf_key_type_id = 0;
3505                         map->btf_value_type_id = 0;
3506                         *pfd = bpf_create_map_xattr(&create_attr);
3507                 }
3508
3509                 if (*pfd < 0) {
3510                         size_t j;
3511
3512                         err = -errno;
3513 err_out:
3514                         cp = libbpf_strerror_r(err, errmsg, sizeof(errmsg));
3515                         pr_warn("failed to create map (name: '%s'): %s(%d)\n",
3516                                 map->name, cp, err);
3517                         pr_perm_msg(err);
3518                         for (j = 0; j < i; j++)
3519                                 zclose(obj->maps[j].fd);
3520                         return err;
3521                 }
3522
3523                 if (bpf_map__is_internal(map)) {
3524                         err = bpf_object__populate_internal_map(obj, map);
3525                         if (err < 0) {
3526                                 zclose(*pfd);
3527                                 goto err_out;
3528                         }
3529                 }
3530
3531                 if (map->pin_path && !map->pinned) {
3532                         err = bpf_map__pin(map, NULL);
3533                         if (err) {
3534                                 pr_warn("failed to auto-pin map name '%s' at '%s'\n",
3535                                         map->name, map->pin_path);
3536                                 return err;
3537                         }
3538                 }
3539
3540                 pr_debug("created map %s: fd=%d\n", map->name, *pfd);
3541         }
3542
3543         return 0;
3544 }
3545
3546 static int
3547 check_btf_ext_reloc_err(struct bpf_program *prog, int err,
3548                         void *btf_prog_info, const char *info_name)
3549 {
3550         if (err != -ENOENT) {
3551                 pr_warn("Error in loading %s for sec %s.\n",
3552                         info_name, prog->section_name);
3553                 return err;
3554         }
3555
3556         /* err == -ENOENT (i.e. prog->section_name not found in btf_ext) */
3557
3558         if (btf_prog_info) {
3559                 /*
3560                  * Some info has already been found but has problem
3561                  * in the last btf_ext reloc. Must have to error out.
3562                  */
3563                 pr_warn("Error in relocating %s for sec %s.\n",
3564                         info_name, prog->section_name);
3565                 return err;
3566         }
3567
3568         /* Have problem loading the very first info. Ignore the rest. */
3569         pr_warn("Cannot find %s for main program sec %s. Ignore all %s.\n",
3570                 info_name, prog->section_name, info_name);
3571         return 0;
3572 }
3573
3574 static int
3575 bpf_program_reloc_btf_ext(struct bpf_program *prog, struct bpf_object *obj,
3576                           const char *section_name,  __u32 insn_offset)
3577 {
3578         int err;
3579
3580         if (!insn_offset || prog->func_info) {
3581                 /*
3582                  * !insn_offset => main program
3583                  *
3584                  * For sub prog, the main program's func_info has to
3585                  * be loaded first (i.e. prog->func_info != NULL)
3586                  */
3587                 err = btf_ext__reloc_func_info(obj->btf, obj->btf_ext,
3588                                                section_name, insn_offset,
3589                                                &prog->func_info,
3590                                                &prog->func_info_cnt);
3591                 if (err)
3592                         return check_btf_ext_reloc_err(prog, err,
3593                                                        prog->func_info,
3594                                                        "bpf_func_info");
3595
3596                 prog->func_info_rec_size = btf_ext__func_info_rec_size(obj->btf_ext);
3597         }
3598
3599         if (!insn_offset || prog->line_info) {
3600                 err = btf_ext__reloc_line_info(obj->btf, obj->btf_ext,
3601                                                section_name, insn_offset,
3602                                                &prog->line_info,
3603                                                &prog->line_info_cnt);
3604                 if (err)
3605                         return check_btf_ext_reloc_err(prog, err,
3606                                                        prog->line_info,
3607                                                        "bpf_line_info");
3608
3609                 prog->line_info_rec_size = btf_ext__line_info_rec_size(obj->btf_ext);
3610         }
3611
3612         return 0;
3613 }
3614
3615 #define BPF_CORE_SPEC_MAX_LEN 64
3616
3617 /* represents BPF CO-RE field or array element accessor */
3618 struct bpf_core_accessor {
3619         __u32 type_id;          /* struct/union type or array element type */
3620         __u32 idx;              /* field index or array index */
3621         const char *name;       /* field name or NULL for array accessor */
3622 };
3623
3624 struct bpf_core_spec {
3625         const struct btf *btf;
3626         /* high-level spec: named fields and array indices only */
3627         struct bpf_core_accessor spec[BPF_CORE_SPEC_MAX_LEN];
3628         /* high-level spec length */
3629         int len;
3630         /* raw, low-level spec: 1-to-1 with accessor spec string */
3631         int raw_spec[BPF_CORE_SPEC_MAX_LEN];
3632         /* raw spec length */
3633         int raw_len;
3634         /* field bit offset represented by spec */
3635         __u32 bit_offset;
3636 };
3637
3638 static bool str_is_empty(const char *s)
3639 {
3640         return !s || !s[0];
3641 }
3642
3643 static bool is_flex_arr(const struct btf *btf,
3644                         const struct bpf_core_accessor *acc,
3645                         const struct btf_array *arr)
3646 {
3647         const struct btf_type *t;
3648
3649         /* not a flexible array, if not inside a struct or has non-zero size */
3650         if (!acc->name || arr->nelems > 0)
3651                 return false;
3652
3653         /* has to be the last member of enclosing struct */
3654         t = btf__type_by_id(btf, acc->type_id);
3655         return acc->idx == btf_vlen(t) - 1;
3656 }
3657
3658 /*
3659  * Turn bpf_field_reloc into a low- and high-level spec representation,
3660  * validating correctness along the way, as well as calculating resulting
3661  * field bit offset, specified by accessor string. Low-level spec captures
3662  * every single level of nestedness, including traversing anonymous
3663  * struct/union members. High-level one only captures semantically meaningful
3664  * "turning points": named fields and array indicies.
3665  * E.g., for this case:
3666  *
3667  *   struct sample {
3668  *       int __unimportant;
3669  *       struct {
3670  *           int __1;
3671  *           int __2;
3672  *           int a[7];
3673  *       };
3674  *   };
3675  *
3676  *   struct sample *s = ...;
3677  *
3678  *   int x = &s->a[3]; // access string = '0:1:2:3'
3679  *
3680  * Low-level spec has 1:1 mapping with each element of access string (it's
3681  * just a parsed access string representation): [0, 1, 2, 3].
3682  *
3683  * High-level spec will capture only 3 points:
3684  *   - intial zero-index access by pointer (&s->... is the same as &s[0]...);
3685  *   - field 'a' access (corresponds to '2' in low-level spec);
3686  *   - array element #3 access (corresponds to '3' in low-level spec).
3687  *
3688  */
3689 static int bpf_core_spec_parse(const struct btf *btf,
3690                                __u32 type_id,
3691                                const char *spec_str,
3692                                struct bpf_core_spec *spec)
3693 {
3694         int access_idx, parsed_len, i;
3695         struct bpf_core_accessor *acc;
3696         const struct btf_type *t;
3697         const char *name;
3698         __u32 id;
3699         __s64 sz;
3700
3701         if (str_is_empty(spec_str) || *spec_str == ':')
3702                 return -EINVAL;
3703
3704         memset(spec, 0, sizeof(*spec));
3705         spec->btf = btf;
3706
3707         /* parse spec_str="0:1:2:3:4" into array raw_spec=[0, 1, 2, 3, 4] */
3708         while (*spec_str) {
3709                 if (*spec_str == ':')
3710                         ++spec_str;
3711                 if (sscanf(spec_str, "%d%n", &access_idx, &parsed_len) != 1)
3712                         return -EINVAL;
3713                 if (spec->raw_len == BPF_CORE_SPEC_MAX_LEN)
3714                         return -E2BIG;
3715                 spec_str += parsed_len;
3716                 spec->raw_spec[spec->raw_len++] = access_idx;
3717         }
3718
3719         if (spec->raw_len == 0)
3720                 return -EINVAL;
3721
3722         /* first spec value is always reloc type array index */
3723         t = skip_mods_and_typedefs(btf, type_id, &id);
3724         if (!t)
3725                 return -EINVAL;
3726
3727         access_idx = spec->raw_spec[0];
3728         spec->spec[0].type_id = id;
3729         spec->spec[0].idx = access_idx;
3730         spec->len++;
3731
3732         sz = btf__resolve_size(btf, id);
3733         if (sz < 0)
3734                 return sz;
3735         spec->bit_offset = access_idx * sz * 8;
3736
3737         for (i = 1; i < spec->raw_len; i++) {
3738                 t = skip_mods_and_typedefs(btf, id, &id);
3739                 if (!t)
3740                         return -EINVAL;
3741
3742                 access_idx = spec->raw_spec[i];
3743                 acc = &spec->spec[spec->len];
3744
3745                 if (btf_is_composite(t)) {
3746                         const struct btf_member *m;
3747                         __u32 bit_offset;
3748
3749                         if (access_idx >= btf_vlen(t))
3750                                 return -EINVAL;
3751
3752                         bit_offset = btf_member_bit_offset(t, access_idx);
3753                         spec->bit_offset += bit_offset;
3754
3755                         m = btf_members(t) + access_idx;
3756                         if (m->name_off) {
3757                                 name = btf__name_by_offset(btf, m->name_off);
3758                                 if (str_is_empty(name))
3759                                         return -EINVAL;
3760
3761                                 acc->type_id = id;
3762                                 acc->idx = access_idx;
3763                                 acc->name = name;
3764                                 spec->len++;
3765                         }
3766
3767                         id = m->type;
3768                 } else if (btf_is_array(t)) {
3769                         const struct btf_array *a = btf_array(t);
3770                         bool flex;
3771
3772                         t = skip_mods_and_typedefs(btf, a->type, &id);
3773                         if (!t)
3774                                 return -EINVAL;
3775
3776                         flex = is_flex_arr(btf, acc - 1, a);
3777                         if (!flex && access_idx >= a->nelems)
3778                                 return -EINVAL;
3779
3780                         spec->spec[spec->len].type_id = id;
3781                         spec->spec[spec->len].idx = access_idx;
3782                         spec->len++;
3783
3784                         sz = btf__resolve_size(btf, id);
3785                         if (sz < 0)
3786                                 return sz;
3787                         spec->bit_offset += access_idx * sz * 8;
3788                 } else {
3789                         pr_warn("relo for [%u] %s (at idx %d) captures type [%d] of unexpected kind %d\n",
3790                                 type_id, spec_str, i, id, btf_kind(t));
3791                         return -EINVAL;
3792                 }
3793         }
3794
3795         return 0;
3796 }
3797
3798 static bool bpf_core_is_flavor_sep(const char *s)
3799 {
3800         /* check X___Y name pattern, where X and Y are not underscores */
3801         return s[0] != '_' &&                                 /* X */
3802                s[1] == '_' && s[2] == '_' && s[3] == '_' &&   /* ___ */
3803                s[4] != '_';                                   /* Y */
3804 }
3805
3806 /* Given 'some_struct_name___with_flavor' return the length of a name prefix
3807  * before last triple underscore. Struct name part after last triple
3808  * underscore is ignored by BPF CO-RE relocation during relocation matching.
3809  */
3810 static size_t bpf_core_essential_name_len(const char *name)
3811 {
3812         size_t n = strlen(name);
3813         int i;
3814
3815         for (i = n - 5; i >= 0; i--) {
3816                 if (bpf_core_is_flavor_sep(name + i))
3817                         return i + 1;
3818         }
3819         return n;
3820 }
3821
3822 /* dynamically sized list of type IDs */
3823 struct ids_vec {
3824         __u32 *data;
3825         int len;
3826 };
3827
3828 static void bpf_core_free_cands(struct ids_vec *cand_ids)
3829 {
3830         free(cand_ids->data);
3831         free(cand_ids);
3832 }
3833
3834 static struct ids_vec *bpf_core_find_cands(const struct btf *local_btf,
3835                                            __u32 local_type_id,
3836                                            const struct btf *targ_btf)
3837 {
3838         size_t local_essent_len, targ_essent_len;
3839         const char *local_name, *targ_name;
3840         const struct btf_type *t;
3841         struct ids_vec *cand_ids;
3842         __u32 *new_ids;
3843         int i, err, n;
3844
3845         t = btf__type_by_id(local_btf, local_type_id);
3846         if (!t)
3847                 return ERR_PTR(-EINVAL);
3848
3849         local_name = btf__name_by_offset(local_btf, t->name_off);
3850         if (str_is_empty(local_name))
3851                 return ERR_PTR(-EINVAL);
3852         local_essent_len = bpf_core_essential_name_len(local_name);
3853
3854         cand_ids = calloc(1, sizeof(*cand_ids));
3855         if (!cand_ids)
3856                 return ERR_PTR(-ENOMEM);
3857
3858         n = btf__get_nr_types(targ_btf);
3859         for (i = 1; i <= n; i++) {
3860                 t = btf__type_by_id(targ_btf, i);
3861                 targ_name = btf__name_by_offset(targ_btf, t->name_off);
3862                 if (str_is_empty(targ_name))
3863                         continue;
3864
3865                 targ_essent_len = bpf_core_essential_name_len(targ_name);
3866                 if (targ_essent_len != local_essent_len)
3867                         continue;
3868
3869                 if (strncmp(local_name, targ_name, local_essent_len) == 0) {
3870                         pr_debug("[%d] %s: found candidate [%d] %s\n",
3871                                  local_type_id, local_name, i, targ_name);
3872                         new_ids = reallocarray(cand_ids->data,
3873                                                cand_ids->len + 1,
3874                                                sizeof(*cand_ids->data));
3875                         if (!new_ids) {
3876                                 err = -ENOMEM;
3877                                 goto err_out;
3878                         }
3879                         cand_ids->data = new_ids;
3880                         cand_ids->data[cand_ids->len++] = i;
3881                 }
3882         }
3883         return cand_ids;
3884 err_out:
3885         bpf_core_free_cands(cand_ids);
3886         return ERR_PTR(err);
3887 }
3888
3889 /* Check two types for compatibility, skipping const/volatile/restrict and
3890  * typedefs, to ensure we are relocating compatible entities:
3891  *   - any two STRUCTs/UNIONs are compatible and can be mixed;
3892  *   - any two FWDs are compatible, if their names match (modulo flavor suffix);
3893  *   - any two PTRs are always compatible;
3894  *   - for ENUMs, names should be the same (ignoring flavor suffix) or at
3895  *     least one of enums should be anonymous;
3896  *   - for ENUMs, check sizes, names are ignored;
3897  *   - for INT, size and signedness are ignored;
3898  *   - for ARRAY, dimensionality is ignored, element types are checked for
3899  *     compatibility recursively;
3900  *   - everything else shouldn't be ever a target of relocation.
3901  * These rules are not set in stone and probably will be adjusted as we get
3902  * more experience with using BPF CO-RE relocations.
3903  */
3904 static int bpf_core_fields_are_compat(const struct btf *local_btf,
3905                                       __u32 local_id,
3906                                       const struct btf *targ_btf,
3907                                       __u32 targ_id)
3908 {
3909         const struct btf_type *local_type, *targ_type;
3910
3911 recur:
3912         local_type = skip_mods_and_typedefs(local_btf, local_id, &local_id);
3913         targ_type = skip_mods_and_typedefs(targ_btf, targ_id, &targ_id);
3914         if (!local_type || !targ_type)
3915                 return -EINVAL;
3916
3917         if (btf_is_composite(local_type) && btf_is_composite(targ_type))
3918                 return 1;
3919         if (btf_kind(local_type) != btf_kind(targ_type))
3920                 return 0;
3921
3922         switch (btf_kind(local_type)) {
3923         case BTF_KIND_PTR:
3924                 return 1;
3925         case BTF_KIND_FWD:
3926         case BTF_KIND_ENUM: {
3927                 const char *local_name, *targ_name;
3928                 size_t local_len, targ_len;
3929
3930                 local_name = btf__name_by_offset(local_btf,
3931                                                  local_type->name_off);
3932                 targ_name = btf__name_by_offset(targ_btf, targ_type->name_off);
3933                 local_len = bpf_core_essential_name_len(local_name);
3934                 targ_len = bpf_core_essential_name_len(targ_name);
3935                 /* one of them is anonymous or both w/ same flavor-less names */
3936                 return local_len == 0 || targ_len == 0 ||
3937                        (local_len == targ_len &&
3938                         strncmp(local_name, targ_name, local_len) == 0);
3939         }
3940         case BTF_KIND_INT:
3941                 /* just reject deprecated bitfield-like integers; all other
3942                  * integers are by default compatible between each other
3943                  */
3944                 return btf_int_offset(local_type) == 0 &&
3945                        btf_int_offset(targ_type) == 0;
3946         case BTF_KIND_ARRAY:
3947                 local_id = btf_array(local_type)->type;
3948                 targ_id = btf_array(targ_type)->type;
3949                 goto recur;
3950         default:
3951                 pr_warn("unexpected kind %d relocated, local [%d], target [%d]\n",
3952                         btf_kind(local_type), local_id, targ_id);
3953                 return 0;
3954         }
3955 }
3956
3957 /*
3958  * Given single high-level named field accessor in local type, find
3959  * corresponding high-level accessor for a target type. Along the way,
3960  * maintain low-level spec for target as well. Also keep updating target
3961  * bit offset.
3962  *
3963  * Searching is performed through recursive exhaustive enumeration of all
3964  * fields of a struct/union. If there are any anonymous (embedded)
3965  * structs/unions, they are recursively searched as well. If field with
3966  * desired name is found, check compatibility between local and target types,
3967  * before returning result.
3968  *
3969  * 1 is returned, if field is found.
3970  * 0 is returned if no compatible field is found.
3971  * <0 is returned on error.
3972  */
3973 static int bpf_core_match_member(const struct btf *local_btf,
3974                                  const struct bpf_core_accessor *local_acc,
3975                                  const struct btf *targ_btf,
3976                                  __u32 targ_id,
3977                                  struct bpf_core_spec *spec,
3978                                  __u32 *next_targ_id)
3979 {
3980         const struct btf_type *local_type, *targ_type;
3981         const struct btf_member *local_member, *m;
3982         const char *local_name, *targ_name;
3983         __u32 local_id;
3984         int i, n, found;
3985
3986         targ_type = skip_mods_and_typedefs(targ_btf, targ_id, &targ_id);
3987         if (!targ_type)
3988                 return -EINVAL;
3989         if (!btf_is_composite(targ_type))
3990                 return 0;
3991
3992         local_id = local_acc->type_id;
3993         local_type = btf__type_by_id(local_btf, local_id);
3994         local_member = btf_members(local_type) + local_acc->idx;
3995         local_name = btf__name_by_offset(local_btf, local_member->name_off);
3996
3997         n = btf_vlen(targ_type);
3998         m = btf_members(targ_type);
3999         for (i = 0; i < n; i++, m++) {
4000                 __u32 bit_offset;
4001
4002                 bit_offset = btf_member_bit_offset(targ_type, i);
4003
4004                 /* too deep struct/union/array nesting */
4005                 if (spec->raw_len == BPF_CORE_SPEC_MAX_LEN)
4006                         return -E2BIG;
4007
4008                 /* speculate this member will be the good one */
4009                 spec->bit_offset += bit_offset;
4010                 spec->raw_spec[spec->raw_len++] = i;
4011
4012                 targ_name = btf__name_by_offset(targ_btf, m->name_off);
4013                 if (str_is_empty(targ_name)) {
4014                         /* embedded struct/union, we need to go deeper */
4015                         found = bpf_core_match_member(local_btf, local_acc,
4016                                                       targ_btf, m->type,
4017                                                       spec, next_targ_id);
4018                         if (found) /* either found or error */
4019                                 return found;
4020                 } else if (strcmp(local_name, targ_name) == 0) {
4021                         /* matching named field */
4022                         struct bpf_core_accessor *targ_acc;
4023
4024                         targ_acc = &spec->spec[spec->len++];
4025                         targ_acc->type_id = targ_id;
4026                         targ_acc->idx = i;
4027                         targ_acc->name = targ_name;
4028
4029                         *next_targ_id = m->type;
4030                         found = bpf_core_fields_are_compat(local_btf,
4031                                                            local_member->type,
4032                                                            targ_btf, m->type);
4033                         if (!found)
4034                                 spec->len--; /* pop accessor */
4035                         return found;
4036                 }
4037                 /* member turned out not to be what we looked for */
4038                 spec->bit_offset -= bit_offset;
4039                 spec->raw_len--;
4040         }
4041
4042         return 0;
4043 }
4044
4045 /*
4046  * Try to match local spec to a target type and, if successful, produce full
4047  * target spec (high-level, low-level + bit offset).
4048  */
4049 static int bpf_core_spec_match(struct bpf_core_spec *local_spec,
4050                                const struct btf *targ_btf, __u32 targ_id,
4051                                struct bpf_core_spec *targ_spec)
4052 {
4053         const struct btf_type *targ_type;
4054         const struct bpf_core_accessor *local_acc;
4055         struct bpf_core_accessor *targ_acc;
4056         int i, sz, matched;
4057
4058         memset(targ_spec, 0, sizeof(*targ_spec));
4059         targ_spec->btf = targ_btf;
4060
4061         local_acc = &local_spec->spec[0];
4062         targ_acc = &targ_spec->spec[0];
4063
4064         for (i = 0; i < local_spec->len; i++, local_acc++, targ_acc++) {
4065                 targ_type = skip_mods_and_typedefs(targ_spec->btf, targ_id,
4066                                                    &targ_id);
4067                 if (!targ_type)
4068                         return -EINVAL;
4069
4070                 if (local_acc->name) {
4071                         matched = bpf_core_match_member(local_spec->btf,
4072                                                         local_acc,
4073                                                         targ_btf, targ_id,
4074                                                         targ_spec, &targ_id);
4075                         if (matched <= 0)
4076                                 return matched;
4077                 } else {
4078                         /* for i=0, targ_id is already treated as array element
4079                          * type (because it's the original struct), for others
4080                          * we should find array element type first
4081                          */
4082                         if (i > 0) {
4083                                 const struct btf_array *a;
4084                                 bool flex;
4085
4086                                 if (!btf_is_array(targ_type))
4087                                         return 0;
4088
4089                                 a = btf_array(targ_type);
4090                                 flex = is_flex_arr(targ_btf, targ_acc - 1, a);
4091                                 if (!flex && local_acc->idx >= a->nelems)
4092                                         return 0;
4093                                 if (!skip_mods_and_typedefs(targ_btf, a->type,
4094                                                             &targ_id))
4095                                         return -EINVAL;
4096                         }
4097
4098                         /* too deep struct/union/array nesting */
4099                         if (targ_spec->raw_len == BPF_CORE_SPEC_MAX_LEN)
4100                                 return -E2BIG;
4101
4102                         targ_acc->type_id = targ_id;
4103                         targ_acc->idx = local_acc->idx;
4104                         targ_acc->name = NULL;
4105                         targ_spec->len++;
4106                         targ_spec->raw_spec[targ_spec->raw_len] = targ_acc->idx;
4107                         targ_spec->raw_len++;
4108
4109                         sz = btf__resolve_size(targ_btf, targ_id);
4110                         if (sz < 0)
4111                                 return sz;
4112                         targ_spec->bit_offset += local_acc->idx * sz * 8;
4113                 }
4114         }
4115
4116         return 1;
4117 }
4118
4119 static int bpf_core_calc_field_relo(const struct bpf_program *prog,
4120                                     const struct bpf_field_reloc *relo,
4121                                     const struct bpf_core_spec *spec,
4122                                     __u32 *val, bool *validate)
4123 {
4124         const struct bpf_core_accessor *acc = &spec->spec[spec->len - 1];
4125         const struct btf_type *t = btf__type_by_id(spec->btf, acc->type_id);
4126         __u32 byte_off, byte_sz, bit_off, bit_sz;
4127         const struct btf_member *m;
4128         const struct btf_type *mt;
4129         bool bitfield;
4130         __s64 sz;
4131
4132         /* a[n] accessor needs special handling */
4133         if (!acc->name) {
4134                 if (relo->kind == BPF_FIELD_BYTE_OFFSET) {
4135                         *val = spec->bit_offset / 8;
4136                 } else if (relo->kind == BPF_FIELD_BYTE_SIZE) {
4137                         sz = btf__resolve_size(spec->btf, acc->type_id);
4138                         if (sz < 0)
4139                                 return -EINVAL;
4140                         *val = sz;
4141                 } else {
4142                         pr_warn("prog '%s': relo %d at insn #%d can't be applied to array access\n",
4143                                 bpf_program__title(prog, false),
4144                                 relo->kind, relo->insn_off / 8);
4145                         return -EINVAL;
4146                 }
4147                 if (validate)
4148                         *validate = true;
4149                 return 0;
4150         }
4151
4152         m = btf_members(t) + acc->idx;
4153         mt = skip_mods_and_typedefs(spec->btf, m->type, NULL);
4154         bit_off = spec->bit_offset;
4155         bit_sz = btf_member_bitfield_size(t, acc->idx);
4156
4157         bitfield = bit_sz > 0;
4158         if (bitfield) {
4159                 byte_sz = mt->size;
4160                 byte_off = bit_off / 8 / byte_sz * byte_sz;
4161                 /* figure out smallest int size necessary for bitfield load */
4162                 while (bit_off + bit_sz - byte_off * 8 > byte_sz * 8) {
4163                         if (byte_sz >= 8) {
4164                                 /* bitfield can't be read with 64-bit read */
4165                                 pr_warn("prog '%s': relo %d at insn #%d can't be satisfied for bitfield\n",
4166                                         bpf_program__title(prog, false),
4167                                         relo->kind, relo->insn_off / 8);
4168                                 return -E2BIG;
4169                         }
4170                         byte_sz *= 2;
4171                         byte_off = bit_off / 8 / byte_sz * byte_sz;
4172                 }
4173         } else {
4174                 sz = btf__resolve_size(spec->btf, m->type);
4175                 if (sz < 0)
4176                         return -EINVAL;
4177                 byte_sz = sz;
4178                 byte_off = spec->bit_offset / 8;
4179                 bit_sz = byte_sz * 8;
4180         }
4181
4182         /* for bitfields, all the relocatable aspects are ambiguous and we
4183          * might disagree with compiler, so turn off validation of expected
4184          * value, except for signedness
4185          */
4186         if (validate)
4187                 *validate = !bitfield;
4188
4189         switch (relo->kind) {
4190         case BPF_FIELD_BYTE_OFFSET:
4191                 *val = byte_off;
4192                 break;
4193         case BPF_FIELD_BYTE_SIZE:
4194                 *val = byte_sz;
4195                 break;
4196         case BPF_FIELD_SIGNED:
4197                 /* enums will be assumed unsigned */
4198                 *val = btf_is_enum(mt) ||
4199                        (btf_int_encoding(mt) & BTF_INT_SIGNED);
4200                 if (validate)
4201                         *validate = true; /* signedness is never ambiguous */
4202                 break;
4203         case BPF_FIELD_LSHIFT_U64:
4204 #if __BYTE_ORDER == __LITTLE_ENDIAN
4205                 *val = 64 - (bit_off + bit_sz - byte_off  * 8);
4206 #else
4207                 *val = (8 - byte_sz) * 8 + (bit_off - byte_off * 8);
4208 #endif
4209                 break;
4210         case BPF_FIELD_RSHIFT_U64:
4211                 *val = 64 - bit_sz;
4212                 if (validate)
4213                         *validate = true; /* right shift is never ambiguous */
4214                 break;
4215         case BPF_FIELD_EXISTS:
4216         default:
4217                 pr_warn("prog '%s': unknown relo %d at insn #%d\n",
4218                         bpf_program__title(prog, false),
4219                         relo->kind, relo->insn_off / 8);
4220                 return -EINVAL;
4221         }
4222
4223         return 0;
4224 }
4225
4226 /*
4227  * Patch relocatable BPF instruction.
4228  *
4229  * Patched value is determined by relocation kind and target specification.
4230  * For field existence relocation target spec will be NULL if field is not
4231  * found.
4232  * Expected insn->imm value is determined using relocation kind and local
4233  * spec, and is checked before patching instruction. If actual insn->imm value
4234  * is wrong, bail out with error.
4235  *
4236  * Currently three kinds of BPF instructions are supported:
4237  * 1. rX = <imm> (assignment with immediate operand);
4238  * 2. rX += <imm> (arithmetic operations with immediate operand);
4239  */
4240 static int bpf_core_reloc_insn(struct bpf_program *prog,
4241                                const struct bpf_field_reloc *relo,
4242                                int relo_idx,
4243                                const struct bpf_core_spec *local_spec,
4244                                const struct bpf_core_spec *targ_spec)
4245 {
4246         __u32 orig_val, new_val;
4247         struct bpf_insn *insn;
4248         bool validate = true;
4249         int insn_idx, err;
4250         __u8 class;
4251
4252         if (relo->insn_off % sizeof(struct bpf_insn))
4253                 return -EINVAL;
4254         insn_idx = relo->insn_off / sizeof(struct bpf_insn);
4255         insn = &prog->insns[insn_idx];
4256         class = BPF_CLASS(insn->code);
4257
4258         if (relo->kind == BPF_FIELD_EXISTS) {
4259                 orig_val = 1; /* can't generate EXISTS relo w/o local field */
4260                 new_val = targ_spec ? 1 : 0;
4261         } else if (!targ_spec) {
4262                 pr_debug("prog '%s': relo #%d: substituting insn #%d w/ invalid insn\n",
4263                          bpf_program__title(prog, false), relo_idx, insn_idx);
4264                 insn->code = BPF_JMP | BPF_CALL;
4265                 insn->dst_reg = 0;
4266                 insn->src_reg = 0;
4267                 insn->off = 0;
4268                 /* if this instruction is reachable (not a dead code),
4269                  * verifier will complain with the following message:
4270                  * invalid func unknown#195896080
4271                  */
4272                 insn->imm = 195896080; /* => 0xbad2310 => "bad relo" */
4273                 return 0;
4274         } else {
4275                 err = bpf_core_calc_field_relo(prog, relo, local_spec,
4276                                                &orig_val, &validate);
4277                 if (err)
4278                         return err;
4279                 err = bpf_core_calc_field_relo(prog, relo, targ_spec,
4280                                                &new_val, NULL);
4281                 if (err)
4282                         return err;
4283         }
4284
4285         switch (class) {
4286         case BPF_ALU:
4287         case BPF_ALU64:
4288                 if (BPF_SRC(insn->code) != BPF_K)
4289                         return -EINVAL;
4290                 if (validate && insn->imm != orig_val) {
4291                         pr_warn("prog '%s': relo #%d: unexpected insn #%d (ALU/ALU64) value: got %u, exp %u -> %u\n",
4292                                 bpf_program__title(prog, false), relo_idx,
4293                                 insn_idx, insn->imm, orig_val, new_val);
4294                         return -EINVAL;
4295                 }
4296                 orig_val = insn->imm;
4297                 insn->imm = new_val;
4298                 pr_debug("prog '%s': relo #%d: patched insn #%d (ALU/ALU64) imm %u -> %u\n",
4299                          bpf_program__title(prog, false), relo_idx, insn_idx,
4300                          orig_val, new_val);
4301                 break;
4302         case BPF_LDX:
4303         case BPF_ST:
4304         case BPF_STX:
4305                 if (validate && insn->off != orig_val) {
4306                         pr_warn("prog '%s': relo #%d: unexpected insn #%d (LD/LDX/ST/STX) value: got %u, exp %u -> %u\n",
4307                                 bpf_program__title(prog, false), relo_idx,
4308                                 insn_idx, insn->off, orig_val, new_val);
4309                         return -EINVAL;
4310                 }
4311                 if (new_val > SHRT_MAX) {
4312                         pr_warn("prog '%s': relo #%d: insn #%d (LDX/ST/STX) value too big: %u\n",
4313                                 bpf_program__title(prog, false), relo_idx,
4314                                 insn_idx, new_val);
4315                         return -ERANGE;
4316                 }
4317                 orig_val = insn->off;
4318                 insn->off = new_val;
4319                 pr_debug("prog '%s': relo #%d: patched insn #%d (LDX/ST/STX) off %u -> %u\n",
4320                          bpf_program__title(prog, false), relo_idx, insn_idx,
4321                          orig_val, new_val);
4322                 break;
4323         default:
4324                 pr_warn("prog '%s': relo #%d: trying to relocate unrecognized insn #%d, code:%x, src:%x, dst:%x, off:%x, imm:%x\n",
4325                         bpf_program__title(prog, false), relo_idx,
4326                         insn_idx, insn->code, insn->src_reg, insn->dst_reg,
4327                         insn->off, insn->imm);
4328                 return -EINVAL;
4329         }
4330
4331         return 0;
4332 }
4333
4334 /* Output spec definition in the format:
4335  * [<type-id>] (<type-name>) + <raw-spec> => <offset>@<spec>,
4336  * where <spec> is a C-syntax view of recorded field access, e.g.: x.a[3].b
4337  */
4338 static void bpf_core_dump_spec(int level, const struct bpf_core_spec *spec)
4339 {
4340         const struct btf_type *t;
4341         const char *s;
4342         __u32 type_id;
4343         int i;
4344
4345         type_id = spec->spec[0].type_id;
4346         t = btf__type_by_id(spec->btf, type_id);
4347         s = btf__name_by_offset(spec->btf, t->name_off);
4348         libbpf_print(level, "[%u] %s + ", type_id, s);
4349
4350         for (i = 0; i < spec->raw_len; i++)
4351                 libbpf_print(level, "%d%s", spec->raw_spec[i],
4352                              i == spec->raw_len - 1 ? " => " : ":");
4353
4354         libbpf_print(level, "%u.%u @ &x",
4355                      spec->bit_offset / 8, spec->bit_offset % 8);
4356
4357         for (i = 0; i < spec->len; i++) {
4358                 if (spec->spec[i].name)
4359                         libbpf_print(level, ".%s", spec->spec[i].name);
4360                 else
4361                         libbpf_print(level, "[%u]", spec->spec[i].idx);
4362         }
4363
4364 }
4365
4366 static size_t bpf_core_hash_fn(const void *key, void *ctx)
4367 {
4368         return (size_t)key;
4369 }
4370
4371 static bool bpf_core_equal_fn(const void *k1, const void *k2, void *ctx)
4372 {
4373         return k1 == k2;
4374 }
4375
4376 static void *u32_as_hash_key(__u32 x)
4377 {
4378         return (void *)(uintptr_t)x;
4379 }
4380
4381 /*
4382  * CO-RE relocate single instruction.
4383  *
4384  * The outline and important points of the algorithm:
4385  * 1. For given local type, find corresponding candidate target types.
4386  *    Candidate type is a type with the same "essential" name, ignoring
4387  *    everything after last triple underscore (___). E.g., `sample`,
4388  *    `sample___flavor_one`, `sample___flavor_another_one`, are all candidates
4389  *    for each other. Names with triple underscore are referred to as
4390  *    "flavors" and are useful, among other things, to allow to
4391  *    specify/support incompatible variations of the same kernel struct, which
4392  *    might differ between different kernel versions and/or build
4393  *    configurations.
4394  *
4395  *    N.B. Struct "flavors" could be generated by bpftool's BTF-to-C
4396  *    converter, when deduplicated BTF of a kernel still contains more than
4397  *    one different types with the same name. In that case, ___2, ___3, etc
4398  *    are appended starting from second name conflict. But start flavors are
4399  *    also useful to be defined "locally", in BPF program, to extract same
4400  *    data from incompatible changes between different kernel
4401  *    versions/configurations. For instance, to handle field renames between
4402  *    kernel versions, one can use two flavors of the struct name with the
4403  *    same common name and use conditional relocations to extract that field,
4404  *    depending on target kernel version.
4405  * 2. For each candidate type, try to match local specification to this
4406  *    candidate target type. Matching involves finding corresponding
4407  *    high-level spec accessors, meaning that all named fields should match,
4408  *    as well as all array accesses should be within the actual bounds. Also,
4409  *    types should be compatible (see bpf_core_fields_are_compat for details).
4410  * 3. It is supported and expected that there might be multiple flavors
4411  *    matching the spec. As long as all the specs resolve to the same set of
4412  *    offsets across all candidates, there is no error. If there is any
4413  *    ambiguity, CO-RE relocation will fail. This is necessary to accomodate
4414  *    imprefection of BTF deduplication, which can cause slight duplication of
4415  *    the same BTF type, if some directly or indirectly referenced (by
4416  *    pointer) type gets resolved to different actual types in different
4417  *    object files. If such situation occurs, deduplicated BTF will end up
4418  *    with two (or more) structurally identical types, which differ only in
4419  *    types they refer to through pointer. This should be OK in most cases and
4420  *    is not an error.
4421  * 4. Candidate types search is performed by linearly scanning through all
4422  *    types in target BTF. It is anticipated that this is overall more
4423  *    efficient memory-wise and not significantly worse (if not better)
4424  *    CPU-wise compared to prebuilding a map from all local type names to
4425  *    a list of candidate type names. It's also sped up by caching resolved
4426  *    list of matching candidates per each local "root" type ID, that has at
4427  *    least one bpf_field_reloc associated with it. This list is shared
4428  *    between multiple relocations for the same type ID and is updated as some
4429  *    of the candidates are pruned due to structural incompatibility.
4430  */
4431 static int bpf_core_reloc_field(struct bpf_program *prog,
4432                                  const struct bpf_field_reloc *relo,
4433                                  int relo_idx,
4434                                  const struct btf *local_btf,
4435                                  const struct btf *targ_btf,
4436                                  struct hashmap *cand_cache)
4437 {
4438         const char *prog_name = bpf_program__title(prog, false);
4439         struct bpf_core_spec local_spec, cand_spec, targ_spec;
4440         const void *type_key = u32_as_hash_key(relo->type_id);
4441         const struct btf_type *local_type, *cand_type;
4442         const char *local_name, *cand_name;
4443         struct ids_vec *cand_ids;
4444         __u32 local_id, cand_id;
4445         const char *spec_str;
4446         int i, j, err;
4447
4448         local_id = relo->type_id;
4449         local_type = btf__type_by_id(local_btf, local_id);
4450         if (!local_type)
4451                 return -EINVAL;
4452
4453         local_name = btf__name_by_offset(local_btf, local_type->name_off);
4454         if (str_is_empty(local_name))
4455                 return -EINVAL;
4456
4457         spec_str = btf__name_by_offset(local_btf, relo->access_str_off);
4458         if (str_is_empty(spec_str))
4459                 return -EINVAL;
4460
4461         err = bpf_core_spec_parse(local_btf, local_id, spec_str, &local_spec);
4462         if (err) {
4463                 pr_warn("prog '%s': relo #%d: parsing [%d] %s + %s failed: %d\n",
4464                         prog_name, relo_idx, local_id, local_name, spec_str,
4465                         err);
4466                 return -EINVAL;
4467         }
4468
4469         pr_debug("prog '%s': relo #%d: kind %d, spec is ", prog_name, relo_idx,
4470                  relo->kind);
4471         bpf_core_dump_spec(LIBBPF_DEBUG, &local_spec);
4472         libbpf_print(LIBBPF_DEBUG, "\n");
4473
4474         if (!hashmap__find(cand_cache, type_key, (void **)&cand_ids)) {
4475                 cand_ids = bpf_core_find_cands(local_btf, local_id, targ_btf);
4476                 if (IS_ERR(cand_ids)) {
4477                         pr_warn("prog '%s': relo #%d: target candidate search failed for [%d] %s: %ld",
4478                                 prog_name, relo_idx, local_id, local_name,
4479                                 PTR_ERR(cand_ids));
4480                         return PTR_ERR(cand_ids);
4481                 }
4482                 err = hashmap__set(cand_cache, type_key, cand_ids, NULL, NULL);
4483                 if (err) {
4484                         bpf_core_free_cands(cand_ids);
4485                         return err;
4486                 }
4487         }
4488
4489         for (i = 0, j = 0; i < cand_ids->len; i++) {
4490                 cand_id = cand_ids->data[i];
4491                 cand_type = btf__type_by_id(targ_btf, cand_id);
4492                 cand_name = btf__name_by_offset(targ_btf, cand_type->name_off);
4493
4494                 err = bpf_core_spec_match(&local_spec, targ_btf,
4495                                           cand_id, &cand_spec);
4496                 pr_debug("prog '%s': relo #%d: matching candidate #%d %s against spec ",
4497                          prog_name, relo_idx, i, cand_name);
4498                 bpf_core_dump_spec(LIBBPF_DEBUG, &cand_spec);
4499                 libbpf_print(LIBBPF_DEBUG, ": %d\n", err);
4500                 if (err < 0) {
4501                         pr_warn("prog '%s': relo #%d: matching error: %d\n",
4502                                 prog_name, relo_idx, err);
4503                         return err;
4504                 }
4505                 if (err == 0)
4506                         continue;
4507
4508                 if (j == 0) {
4509                         targ_spec = cand_spec;
4510                 } else if (cand_spec.bit_offset != targ_spec.bit_offset) {
4511                         /* if there are many candidates, they should all
4512                          * resolve to the same bit offset
4513                          */
4514                         pr_warn("prog '%s': relo #%d: offset ambiguity: %u != %u\n",
4515                                 prog_name, relo_idx, cand_spec.bit_offset,
4516                                 targ_spec.bit_offset);
4517                         return -EINVAL;
4518                 }
4519
4520                 cand_ids->data[j++] = cand_spec.spec[0].type_id;
4521         }
4522
4523         /*
4524          * For BPF_FIELD_EXISTS relo or when used BPF program has field
4525          * existence checks or kernel version/config checks, it's expected
4526          * that we might not find any candidates. In this case, if field
4527          * wasn't found in any candidate, the list of candidates shouldn't
4528          * change at all, we'll just handle relocating appropriately,
4529          * depending on relo's kind.
4530          */
4531         if (j > 0)
4532                 cand_ids->len = j;
4533
4534         /*
4535          * If no candidates were found, it might be both a programmer error,
4536          * as well as expected case, depending whether instruction w/
4537          * relocation is guarded in some way that makes it unreachable (dead
4538          * code) if relocation can't be resolved. This is handled in
4539          * bpf_core_reloc_insn() uniformly by replacing that instruction with
4540          * BPF helper call insn (using invalid helper ID). If that instruction
4541          * is indeed unreachable, then it will be ignored and eliminated by
4542          * verifier. If it was an error, then verifier will complain and point
4543          * to a specific instruction number in its log.
4544          */
4545         if (j == 0)
4546                 pr_debug("prog '%s': relo #%d: no matching targets found for [%d] %s + %s\n",
4547                          prog_name, relo_idx, local_id, local_name, spec_str);
4548
4549         /* bpf_core_reloc_insn should know how to handle missing targ_spec */
4550         err = bpf_core_reloc_insn(prog, relo, relo_idx, &local_spec,
4551                                   j ? &targ_spec : NULL);
4552         if (err) {
4553                 pr_warn("prog '%s': relo #%d: failed to patch insn at offset %d: %d\n",
4554                         prog_name, relo_idx, relo->insn_off, err);
4555                 return -EINVAL;
4556         }
4557
4558         return 0;
4559 }
4560
4561 static int
4562 bpf_core_reloc_fields(struct bpf_object *obj, const char *targ_btf_path)
4563 {
4564         const struct btf_ext_info_sec *sec;
4565         const struct bpf_field_reloc *rec;
4566         const struct btf_ext_info *seg;
4567         struct hashmap_entry *entry;
4568         struct hashmap *cand_cache = NULL;
4569         struct bpf_program *prog;
4570         struct btf *targ_btf;
4571         const char *sec_name;
4572         int i, err = 0;
4573
4574         if (targ_btf_path)
4575                 targ_btf = btf__parse_elf(targ_btf_path, NULL);
4576         else
4577                 targ_btf = libbpf_find_kernel_btf();
4578         if (IS_ERR(targ_btf)) {
4579                 pr_warn("failed to get target BTF: %ld\n", PTR_ERR(targ_btf));
4580                 return PTR_ERR(targ_btf);
4581         }
4582
4583         cand_cache = hashmap__new(bpf_core_hash_fn, bpf_core_equal_fn, NULL);
4584         if (IS_ERR(cand_cache)) {
4585                 err = PTR_ERR(cand_cache);
4586                 goto out;
4587         }
4588
4589         seg = &obj->btf_ext->field_reloc_info;
4590         for_each_btf_ext_sec(seg, sec) {
4591                 sec_name = btf__name_by_offset(obj->btf, sec->sec_name_off);
4592                 if (str_is_empty(sec_name)) {
4593                         err = -EINVAL;
4594                         goto out;
4595                 }
4596                 prog = bpf_object__find_program_by_title(obj, sec_name);
4597                 if (!prog) {
4598                         pr_warn("failed to find program '%s' for CO-RE offset relocation\n",
4599                                 sec_name);
4600                         err = -EINVAL;
4601                         goto out;
4602                 }
4603
4604                 pr_debug("prog '%s': performing %d CO-RE offset relocs\n",
4605                          sec_name, sec->num_info);
4606
4607                 for_each_btf_ext_rec(seg, sec, i, rec) {
4608                         err = bpf_core_reloc_field(prog, rec, i, obj->btf,
4609                                                    targ_btf, cand_cache);
4610                         if (err) {
4611                                 pr_warn("prog '%s': relo #%d: failed to relocate: %d\n",
4612                                         sec_name, i, err);
4613                                 goto out;
4614                         }
4615                 }
4616         }
4617
4618 out:
4619         btf__free(targ_btf);
4620         if (!IS_ERR_OR_NULL(cand_cache)) {
4621                 hashmap__for_each_entry(cand_cache, entry, i) {
4622                         bpf_core_free_cands(entry->value);
4623                 }
4624                 hashmap__free(cand_cache);
4625         }
4626         return err;
4627 }
4628
4629 static int
4630 bpf_object__relocate_core(struct bpf_object *obj, const char *targ_btf_path)
4631 {
4632         int err = 0;
4633
4634         if (obj->btf_ext->field_reloc_info.len)
4635                 err = bpf_core_reloc_fields(obj, targ_btf_path);
4636
4637         return err;
4638 }
4639
4640 static int
4641 bpf_program__reloc_text(struct bpf_program *prog, struct bpf_object *obj,
4642                         struct reloc_desc *relo)
4643 {
4644         struct bpf_insn *insn, *new_insn;
4645         struct bpf_program *text;
4646         size_t new_cnt;
4647         int err;
4648
4649         if (prog->idx != obj->efile.text_shndx && prog->main_prog_cnt == 0) {
4650                 text = bpf_object__find_prog_by_idx(obj, obj->efile.text_shndx);
4651                 if (!text) {
4652                         pr_warn("no .text section found yet relo into text exist\n");
4653                         return -LIBBPF_ERRNO__RELOC;
4654                 }
4655                 new_cnt = prog->insns_cnt + text->insns_cnt;
4656                 new_insn = reallocarray(prog->insns, new_cnt, sizeof(*insn));
4657                 if (!new_insn) {
4658                         pr_warn("oom in prog realloc\n");
4659                         return -ENOMEM;
4660                 }
4661                 prog->insns = new_insn;
4662
4663                 if (obj->btf_ext) {
4664                         err = bpf_program_reloc_btf_ext(prog, obj,
4665                                                         text->section_name,
4666                                                         prog->insns_cnt);
4667                         if (err)
4668                                 return err;
4669                 }
4670
4671                 memcpy(new_insn + prog->insns_cnt, text->insns,
4672                        text->insns_cnt * sizeof(*insn));
4673                 prog->main_prog_cnt = prog->insns_cnt;
4674                 prog->insns_cnt = new_cnt;
4675                 pr_debug("added %zd insn from %s to prog %s\n",
4676                          text->insns_cnt, text->section_name,
4677                          prog->section_name);
4678         }
4679
4680         insn = &prog->insns[relo->insn_idx];
4681         insn->imm += relo->sym_off / 8 + prog->main_prog_cnt - relo->insn_idx;
4682         return 0;
4683 }
4684
4685 static int
4686 bpf_program__relocate(struct bpf_program *prog, struct bpf_object *obj)
4687 {
4688         int i, err;
4689
4690         if (!prog)
4691                 return 0;
4692
4693         if (obj->btf_ext) {
4694                 err = bpf_program_reloc_btf_ext(prog, obj,
4695                                                 prog->section_name, 0);
4696                 if (err)
4697                         return err;
4698         }
4699
4700         if (!prog->reloc_desc)
4701                 return 0;
4702
4703         for (i = 0; i < prog->nr_reloc; i++) {
4704                 struct reloc_desc *relo = &prog->reloc_desc[i];
4705                 struct bpf_insn *insn = &prog->insns[relo->insn_idx];
4706
4707                 if (relo->insn_idx + 1 >= (int)prog->insns_cnt) {
4708                         pr_warn("relocation out of range: '%s'\n",
4709                                 prog->section_name);
4710                         return -LIBBPF_ERRNO__RELOC;
4711                 }
4712
4713                 switch (relo->type) {
4714                 case RELO_LD64:
4715                         insn[0].src_reg = BPF_PSEUDO_MAP_FD;
4716                         insn[0].imm = obj->maps[relo->map_idx].fd;
4717                         break;
4718                 case RELO_DATA:
4719                         insn[0].src_reg = BPF_PSEUDO_MAP_VALUE;
4720                         insn[1].imm = insn[0].imm + relo->sym_off;
4721                         insn[0].imm = obj->maps[relo->map_idx].fd;
4722                         break;
4723                 case RELO_EXTERN:
4724                         insn[0].src_reg = BPF_PSEUDO_MAP_VALUE;
4725                         insn[0].imm = obj->maps[obj->kconfig_map_idx].fd;
4726                         insn[1].imm = relo->sym_off;
4727                         break;
4728                 case RELO_CALL:
4729                         err = bpf_program__reloc_text(prog, obj, relo);
4730                         if (err)
4731                                 return err;
4732                         break;
4733                 default:
4734                         pr_warn("relo #%d: bad relo type %d\n", i, relo->type);
4735                         return -EINVAL;
4736                 }
4737         }
4738
4739         zfree(&prog->reloc_desc);
4740         prog->nr_reloc = 0;
4741         return 0;
4742 }
4743
4744 static int
4745 bpf_object__relocate(struct bpf_object *obj, const char *targ_btf_path)
4746 {
4747         struct bpf_program *prog;
4748         size_t i;
4749         int err;
4750
4751         if (obj->btf_ext) {
4752                 err = bpf_object__relocate_core(obj, targ_btf_path);
4753                 if (err) {
4754                         pr_warn("failed to perform CO-RE relocations: %d\n",
4755                                 err);
4756                         return err;
4757                 }
4758         }
4759         /* ensure .text is relocated first, as it's going to be copied as-is
4760          * later for sub-program calls
4761          */
4762         for (i = 0; i < obj->nr_programs; i++) {
4763                 prog = &obj->programs[i];
4764                 if (prog->idx != obj->efile.text_shndx)
4765                         continue;
4766
4767                 err = bpf_program__relocate(prog, obj);
4768                 if (err) {
4769                         pr_warn("failed to relocate '%s'\n", prog->section_name);
4770                         return err;
4771                 }
4772                 break;
4773         }
4774         /* now relocate everything but .text, which by now is relocated
4775          * properly, so we can copy raw sub-program instructions as is safely
4776          */
4777         for (i = 0; i < obj->nr_programs; i++) {
4778                 prog = &obj->programs[i];
4779                 if (prog->idx == obj->efile.text_shndx)
4780                         continue;
4781
4782                 err = bpf_program__relocate(prog, obj);
4783                 if (err) {
4784                         pr_warn("failed to relocate '%s'\n", prog->section_name);
4785                         return err;
4786                 }
4787         }
4788         return 0;
4789 }
4790
4791 static int bpf_object__collect_struct_ops_map_reloc(struct bpf_object *obj,
4792                                                     GElf_Shdr *shdr,
4793                                                     Elf_Data *data);
4794
4795 static int bpf_object__collect_reloc(struct bpf_object *obj)
4796 {
4797         int i, err;
4798
4799         if (!obj_elf_valid(obj)) {
4800                 pr_warn("Internal error: elf object is closed\n");
4801                 return -LIBBPF_ERRNO__INTERNAL;
4802         }
4803
4804         for (i = 0; i < obj->efile.nr_reloc_sects; i++) {
4805                 GElf_Shdr *shdr = &obj->efile.reloc_sects[i].shdr;
4806                 Elf_Data *data = obj->efile.reloc_sects[i].data;
4807                 int idx = shdr->sh_info;
4808                 struct bpf_program *prog;
4809
4810                 if (shdr->sh_type != SHT_REL) {
4811                         pr_warn("internal error at %d\n", __LINE__);
4812                         return -LIBBPF_ERRNO__INTERNAL;
4813                 }
4814
4815                 if (idx == obj->efile.st_ops_shndx) {
4816                         err = bpf_object__collect_struct_ops_map_reloc(obj,
4817                                                                        shdr,
4818                                                                        data);
4819                         if (err)
4820                                 return err;
4821                         continue;
4822                 }
4823
4824                 prog = bpf_object__find_prog_by_idx(obj, idx);
4825                 if (!prog) {
4826                         pr_warn("relocation failed: no section(%d)\n", idx);
4827                         return -LIBBPF_ERRNO__RELOC;
4828                 }
4829
4830                 err = bpf_program__collect_reloc(prog, shdr, data, obj);
4831                 if (err)
4832                         return err;
4833         }
4834         return 0;
4835 }
4836
4837 static int
4838 load_program(struct bpf_program *prog, struct bpf_insn *insns, int insns_cnt,
4839              char *license, __u32 kern_version, int *pfd)
4840 {
4841         struct bpf_load_program_attr load_attr;
4842         char *cp, errmsg[STRERR_BUFSIZE];
4843         int log_buf_size = BPF_LOG_BUF_SIZE;
4844         char *log_buf;
4845         int btf_fd, ret;
4846
4847         if (!insns || !insns_cnt)
4848                 return -EINVAL;
4849
4850         memset(&load_attr, 0, sizeof(struct bpf_load_program_attr));
4851         load_attr.prog_type = prog->type;
4852         load_attr.expected_attach_type = prog->expected_attach_type;
4853         if (prog->caps->name)
4854                 load_attr.name = prog->name;
4855         load_attr.insns = insns;
4856         load_attr.insns_cnt = insns_cnt;
4857         load_attr.license = license;
4858         if (prog->type == BPF_PROG_TYPE_STRUCT_OPS) {
4859                 load_attr.attach_btf_id = prog->attach_btf_id;
4860         } else if (prog->type == BPF_PROG_TYPE_TRACING ||
4861                    prog->type == BPF_PROG_TYPE_EXT) {
4862                 load_attr.attach_prog_fd = prog->attach_prog_fd;
4863                 load_attr.attach_btf_id = prog->attach_btf_id;
4864         } else {
4865                 load_attr.kern_version = kern_version;
4866                 load_attr.prog_ifindex = prog->prog_ifindex;
4867         }
4868         /* if .BTF.ext was loaded, kernel supports associated BTF for prog */
4869         if (prog->obj->btf_ext)
4870                 btf_fd = bpf_object__btf_fd(prog->obj);
4871         else
4872                 btf_fd = -1;
4873         load_attr.prog_btf_fd = btf_fd >= 0 ? btf_fd : 0;
4874         load_attr.func_info = prog->func_info;
4875         load_attr.func_info_rec_size = prog->func_info_rec_size;
4876         load_attr.func_info_cnt = prog->func_info_cnt;
4877         load_attr.line_info = prog->line_info;
4878         load_attr.line_info_rec_size = prog->line_info_rec_size;
4879         load_attr.line_info_cnt = prog->line_info_cnt;
4880         load_attr.log_level = prog->log_level;
4881         load_attr.prog_flags = prog->prog_flags;
4882
4883 retry_load:
4884         log_buf = malloc(log_buf_size);
4885         if (!log_buf)
4886                 pr_warn("Alloc log buffer for bpf loader error, continue without log\n");
4887
4888         ret = bpf_load_program_xattr(&load_attr, log_buf, log_buf_size);
4889
4890         if (ret >= 0) {
4891                 if (load_attr.log_level)
4892                         pr_debug("verifier log:\n%s", log_buf);
4893                 *pfd = ret;
4894                 ret = 0;
4895                 goto out;
4896         }
4897
4898         if (errno == ENOSPC) {
4899                 log_buf_size <<= 1;
4900                 free(log_buf);
4901                 goto retry_load;
4902         }
4903         ret = -errno;
4904         cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg));
4905         pr_warn("load bpf program failed: %s\n", cp);
4906         pr_perm_msg(ret);
4907
4908         if (log_buf && log_buf[0] != '\0') {
4909                 ret = -LIBBPF_ERRNO__VERIFY;
4910                 pr_warn("-- BEGIN DUMP LOG ---\n");
4911                 pr_warn("\n%s\n", log_buf);
4912                 pr_warn("-- END LOG --\n");
4913         } else if (load_attr.insns_cnt >= BPF_MAXINSNS) {
4914                 pr_warn("Program too large (%zu insns), at most %d insns\n",
4915                         load_attr.insns_cnt, BPF_MAXINSNS);
4916                 ret = -LIBBPF_ERRNO__PROG2BIG;
4917         } else if (load_attr.prog_type != BPF_PROG_TYPE_KPROBE) {
4918                 /* Wrong program type? */
4919                 int fd;
4920
4921                 load_attr.prog_type = BPF_PROG_TYPE_KPROBE;
4922                 load_attr.expected_attach_type = 0;
4923                 fd = bpf_load_program_xattr(&load_attr, NULL, 0);
4924                 if (fd >= 0) {
4925                         close(fd);
4926                         ret = -LIBBPF_ERRNO__PROGTYPE;
4927                         goto out;
4928                 }
4929         }
4930
4931 out:
4932         free(log_buf);
4933         return ret;
4934 }
4935
4936 static int libbpf_find_attach_btf_id(struct bpf_program *prog);
4937
4938 int bpf_program__load(struct bpf_program *prog, char *license, __u32 kern_ver)
4939 {
4940         int err = 0, fd, i, btf_id;
4941
4942         if (prog->type == BPF_PROG_TYPE_TRACING ||
4943             prog->type == BPF_PROG_TYPE_EXT) {
4944                 btf_id = libbpf_find_attach_btf_id(prog);
4945                 if (btf_id <= 0)
4946                         return btf_id;
4947                 prog->attach_btf_id = btf_id;
4948         }
4949
4950         if (prog->instances.nr < 0 || !prog->instances.fds) {
4951                 if (prog->preprocessor) {
4952                         pr_warn("Internal error: can't load program '%s'\n",
4953                                 prog->section_name);
4954                         return -LIBBPF_ERRNO__INTERNAL;
4955                 }
4956
4957                 prog->instances.fds = malloc(sizeof(int));
4958                 if (!prog->instances.fds) {
4959                         pr_warn("Not enough memory for BPF fds\n");
4960                         return -ENOMEM;
4961                 }
4962                 prog->instances.nr = 1;
4963                 prog->instances.fds[0] = -1;
4964         }
4965
4966         if (!prog->preprocessor) {
4967                 if (prog->instances.nr != 1) {
4968                         pr_warn("Program '%s' is inconsistent: nr(%d) != 1\n",
4969                                 prog->section_name, prog->instances.nr);
4970                 }
4971                 err = load_program(prog, prog->insns, prog->insns_cnt,
4972                                    license, kern_ver, &fd);
4973                 if (!err)
4974                         prog->instances.fds[0] = fd;
4975                 goto out;
4976         }
4977
4978         for (i = 0; i < prog->instances.nr; i++) {
4979                 struct bpf_prog_prep_result result;
4980                 bpf_program_prep_t preprocessor = prog->preprocessor;
4981
4982                 memset(&result, 0, sizeof(result));
4983                 err = preprocessor(prog, i, prog->insns,
4984                                    prog->insns_cnt, &result);
4985                 if (err) {
4986                         pr_warn("Preprocessing the %dth instance of program '%s' failed\n",
4987                                 i, prog->section_name);
4988                         goto out;
4989                 }
4990
4991                 if (!result.new_insn_ptr || !result.new_insn_cnt) {
4992                         pr_debug("Skip loading the %dth instance of program '%s'\n",
4993                                  i, prog->section_name);
4994                         prog->instances.fds[i] = -1;
4995                         if (result.pfd)
4996                                 *result.pfd = -1;
4997                         continue;
4998                 }
4999
5000                 err = load_program(prog, result.new_insn_ptr,
5001                                    result.new_insn_cnt, license, kern_ver, &fd);
5002                 if (err) {
5003                         pr_warn("Loading the %dth instance of program '%s' failed\n",
5004                                 i, prog->section_name);
5005                         goto out;
5006                 }
5007
5008                 if (result.pfd)
5009                         *result.pfd = fd;
5010                 prog->instances.fds[i] = fd;
5011         }
5012 out:
5013         if (err)
5014                 pr_warn("failed to load program '%s'\n", prog->section_name);
5015         zfree(&prog->insns);
5016         prog->insns_cnt = 0;
5017         return err;
5018 }
5019
5020 static bool bpf_program__is_function_storage(const struct bpf_program *prog,
5021                                              const struct bpf_object *obj)
5022 {
5023         return prog->idx == obj->efile.text_shndx && obj->has_pseudo_calls;
5024 }
5025
5026 static int
5027 bpf_object__load_progs(struct bpf_object *obj, int log_level)
5028 {
5029         size_t i;
5030         int err;
5031
5032         for (i = 0; i < obj->nr_programs; i++) {
5033                 if (bpf_program__is_function_storage(&obj->programs[i], obj))
5034                         continue;
5035                 obj->programs[i].log_level |= log_level;
5036                 err = bpf_program__load(&obj->programs[i],
5037                                         obj->license,
5038                                         obj->kern_version);
5039                 if (err)
5040                         return err;
5041         }
5042         return 0;
5043 }
5044
5045 static struct bpf_object *
5046 __bpf_object__open(const char *path, const void *obj_buf, size_t obj_buf_sz,
5047                    const struct bpf_object_open_opts *opts)
5048 {
5049         const char *obj_name, *kconfig;
5050         struct bpf_program *prog;
5051         struct bpf_object *obj;
5052         char tmp_name[64];
5053         int err;
5054
5055         if (elf_version(EV_CURRENT) == EV_NONE) {
5056                 pr_warn("failed to init libelf for %s\n",
5057                         path ? : "(mem buf)");
5058                 return ERR_PTR(-LIBBPF_ERRNO__LIBELF);
5059         }
5060
5061         if (!OPTS_VALID(opts, bpf_object_open_opts))
5062                 return ERR_PTR(-EINVAL);
5063
5064         obj_name = OPTS_GET(opts, object_name, NULL);
5065         if (obj_buf) {
5066                 if (!obj_name) {
5067                         snprintf(tmp_name, sizeof(tmp_name), "%lx-%lx",
5068                                  (unsigned long)obj_buf,
5069                                  (unsigned long)obj_buf_sz);
5070                         obj_name = tmp_name;
5071                 }
5072                 path = obj_name;
5073                 pr_debug("loading object '%s' from buffer\n", obj_name);
5074         }
5075
5076         obj = bpf_object__new(path, obj_buf, obj_buf_sz, obj_name);
5077         if (IS_ERR(obj))
5078                 return obj;
5079
5080         kconfig = OPTS_GET(opts, kconfig, NULL);
5081         if (kconfig) {
5082                 obj->kconfig = strdup(kconfig);
5083                 if (!obj->kconfig)
5084                         return ERR_PTR(-ENOMEM);
5085         }
5086
5087         err = bpf_object__elf_init(obj);
5088         err = err ? : bpf_object__check_endianness(obj);
5089         err = err ? : bpf_object__elf_collect(obj);
5090         err = err ? : bpf_object__collect_externs(obj);
5091         err = err ? : bpf_object__finalize_btf(obj);
5092         err = err ? : bpf_object__init_maps(obj, opts);
5093         err = err ? : bpf_object__init_prog_names(obj);
5094         err = err ? : bpf_object__collect_reloc(obj);
5095         if (err)
5096                 goto out;
5097         bpf_object__elf_finish(obj);
5098
5099         bpf_object__for_each_program(prog, obj) {
5100                 enum bpf_prog_type prog_type;
5101                 enum bpf_attach_type attach_type;
5102
5103                 if (prog->type != BPF_PROG_TYPE_UNSPEC)
5104                         continue;
5105
5106                 err = libbpf_prog_type_by_name(prog->section_name, &prog_type,
5107                                                &attach_type);
5108                 if (err == -ESRCH)
5109                         /* couldn't guess, but user might manually specify */
5110                         continue;
5111                 if (err)
5112                         goto out;
5113
5114                 bpf_program__set_type(prog, prog_type);
5115                 bpf_program__set_expected_attach_type(prog, attach_type);
5116                 if (prog_type == BPF_PROG_TYPE_TRACING ||
5117                     prog_type == BPF_PROG_TYPE_EXT)
5118                         prog->attach_prog_fd = OPTS_GET(opts, attach_prog_fd, 0);
5119         }
5120
5121         return obj;
5122 out:
5123         bpf_object__close(obj);
5124         return ERR_PTR(err);
5125 }
5126
5127 static struct bpf_object *
5128 __bpf_object__open_xattr(struct bpf_object_open_attr *attr, int flags)
5129 {
5130         DECLARE_LIBBPF_OPTS(bpf_object_open_opts, opts,
5131                 .relaxed_maps = flags & MAPS_RELAX_COMPAT,
5132         );
5133
5134         /* param validation */
5135         if (!attr->file)
5136                 return NULL;
5137
5138         pr_debug("loading %s\n", attr->file);
5139         return __bpf_object__open(attr->file, NULL, 0, &opts);
5140 }
5141
5142 struct bpf_object *bpf_object__open_xattr(struct bpf_object_open_attr *attr)
5143 {
5144         return __bpf_object__open_xattr(attr, 0);
5145 }
5146
5147 struct bpf_object *bpf_object__open(const char *path)
5148 {
5149         struct bpf_object_open_attr attr = {
5150                 .file           = path,
5151                 .prog_type      = BPF_PROG_TYPE_UNSPEC,
5152         };
5153
5154         return bpf_object__open_xattr(&attr);
5155 }
5156
5157 struct bpf_object *
5158 bpf_object__open_file(const char *path, const struct bpf_object_open_opts *opts)
5159 {
5160         if (!path)
5161                 return ERR_PTR(-EINVAL);
5162
5163         pr_debug("loading %s\n", path);
5164
5165         return __bpf_object__open(path, NULL, 0, opts);
5166 }
5167
5168 struct bpf_object *
5169 bpf_object__open_mem(const void *obj_buf, size_t obj_buf_sz,
5170                      const struct bpf_object_open_opts *opts)
5171 {
5172         if (!obj_buf || obj_buf_sz == 0)
5173                 return ERR_PTR(-EINVAL);
5174
5175         return __bpf_object__open(NULL, obj_buf, obj_buf_sz, opts);
5176 }
5177
5178 struct bpf_object *
5179 bpf_object__open_buffer(const void *obj_buf, size_t obj_buf_sz,
5180                         const char *name)
5181 {
5182         DECLARE_LIBBPF_OPTS(bpf_object_open_opts, opts,
5183                 .object_name = name,
5184                 /* wrong default, but backwards-compatible */
5185                 .relaxed_maps = true,
5186         );
5187
5188         /* returning NULL is wrong, but backwards-compatible */
5189         if (!obj_buf || obj_buf_sz == 0)
5190                 return NULL;
5191
5192         return bpf_object__open_mem(obj_buf, obj_buf_sz, &opts);
5193 }
5194
5195 int bpf_object__unload(struct bpf_object *obj)
5196 {
5197         size_t i;
5198
5199         if (!obj)
5200                 return -EINVAL;
5201
5202         for (i = 0; i < obj->nr_maps; i++) {
5203                 zclose(obj->maps[i].fd);
5204                 if (obj->maps[i].st_ops)
5205                         zfree(&obj->maps[i].st_ops->kern_vdata);
5206         }
5207
5208         for (i = 0; i < obj->nr_programs; i++)
5209                 bpf_program__unload(&obj->programs[i]);
5210
5211         return 0;
5212 }
5213
5214 static int bpf_object__sanitize_maps(struct bpf_object *obj)
5215 {
5216         struct bpf_map *m;
5217
5218         bpf_object__for_each_map(m, obj) {
5219                 if (!bpf_map__is_internal(m))
5220                         continue;
5221                 if (!obj->caps.global_data) {
5222                         pr_warn("kernel doesn't support global data\n");
5223                         return -ENOTSUP;
5224                 }
5225                 if (!obj->caps.array_mmap)
5226                         m->def.map_flags ^= BPF_F_MMAPABLE;
5227         }
5228
5229         return 0;
5230 }
5231
5232 static int bpf_object__resolve_externs(struct bpf_object *obj,
5233                                        const char *extra_kconfig)
5234 {
5235         bool need_config = false;
5236         struct extern_desc *ext;
5237         int err, i;
5238         void *data;
5239
5240         if (obj->nr_extern == 0)
5241                 return 0;
5242
5243         data = obj->maps[obj->kconfig_map_idx].mmaped;
5244
5245         for (i = 0; i < obj->nr_extern; i++) {
5246                 ext = &obj->externs[i];
5247
5248                 if (strcmp(ext->name, "LINUX_KERNEL_VERSION") == 0) {
5249                         void *ext_val = data + ext->data_off;
5250                         __u32 kver = get_kernel_version();
5251
5252                         if (!kver) {
5253                                 pr_warn("failed to get kernel version\n");
5254                                 return -EINVAL;
5255                         }
5256                         err = set_ext_value_num(ext, ext_val, kver);
5257                         if (err)
5258                                 return err;
5259                         pr_debug("extern %s=0x%x\n", ext->name, kver);
5260                 } else if (strncmp(ext->name, "CONFIG_", 7) == 0) {
5261                         need_config = true;
5262                 } else {
5263                         pr_warn("unrecognized extern '%s'\n", ext->name);
5264                         return -EINVAL;
5265                 }
5266         }
5267         if (need_config && extra_kconfig) {
5268                 err = bpf_object__read_kconfig_mem(obj, extra_kconfig, data);
5269                 if (err)
5270                         return -EINVAL;
5271                 need_config = false;
5272                 for (i = 0; i < obj->nr_extern; i++) {
5273                         ext = &obj->externs[i];
5274                         if (!ext->is_set) {
5275                                 need_config = true;
5276                                 break;
5277                         }
5278                 }
5279         }
5280         if (need_config) {
5281                 err = bpf_object__read_kconfig_file(obj, data);
5282                 if (err)
5283                         return -EINVAL;
5284         }
5285         for (i = 0; i < obj->nr_extern; i++) {
5286                 ext = &obj->externs[i];
5287
5288                 if (!ext->is_set && !ext->is_weak) {
5289                         pr_warn("extern %s (strong) not resolved\n", ext->name);
5290                         return -ESRCH;
5291                 } else if (!ext->is_set) {
5292                         pr_debug("extern %s (weak) not resolved, defaulting to zero\n",
5293                                  ext->name);
5294                 }
5295         }
5296
5297         return 0;
5298 }
5299
5300 int bpf_object__load_xattr(struct bpf_object_load_attr *attr)
5301 {
5302         struct bpf_object *obj;
5303         int err, i;
5304
5305         if (!attr)
5306                 return -EINVAL;
5307         obj = attr->obj;
5308         if (!obj)
5309                 return -EINVAL;
5310
5311         if (obj->loaded) {
5312                 pr_warn("object should not be loaded twice\n");
5313                 return -EINVAL;
5314         }
5315
5316         obj->loaded = true;
5317
5318         err = bpf_object__probe_caps(obj);
5319         err = err ? : bpf_object__resolve_externs(obj, obj->kconfig);
5320         err = err ? : bpf_object__sanitize_and_load_btf(obj);
5321         err = err ? : bpf_object__sanitize_maps(obj);
5322         err = err ? : bpf_object__load_vmlinux_btf(obj);
5323         err = err ? : bpf_object__init_kern_struct_ops_maps(obj);
5324         err = err ? : bpf_object__create_maps(obj);
5325         err = err ? : bpf_object__relocate(obj, attr->target_btf_path);
5326         err = err ? : bpf_object__load_progs(obj, attr->log_level);
5327
5328         btf__free(obj->btf_vmlinux);
5329         obj->btf_vmlinux = NULL;
5330
5331         if (err)
5332                 goto out;
5333
5334         return 0;
5335 out:
5336         /* unpin any maps that were auto-pinned during load */
5337         for (i = 0; i < obj->nr_maps; i++)
5338                 if (obj->maps[i].pinned && !obj->maps[i].reused)
5339                         bpf_map__unpin(&obj->maps[i], NULL);
5340
5341         bpf_object__unload(obj);
5342         pr_warn("failed to load object '%s'\n", obj->path);
5343         return err;
5344 }
5345
5346 int bpf_object__load(struct bpf_object *obj)
5347 {
5348         struct bpf_object_load_attr attr = {
5349                 .obj = obj,
5350         };
5351
5352         return bpf_object__load_xattr(&attr);
5353 }
5354
5355 static int make_parent_dir(const char *path)
5356 {
5357         char *cp, errmsg[STRERR_BUFSIZE];
5358         char *dname, *dir;
5359         int err = 0;
5360
5361         dname = strdup(path);
5362         if (dname == NULL)
5363                 return -ENOMEM;
5364
5365         dir = dirname(dname);
5366         if (mkdir(dir, 0700) && errno != EEXIST)
5367                 err = -errno;
5368
5369         free(dname);
5370         if (err) {
5371                 cp = libbpf_strerror_r(-err, errmsg, sizeof(errmsg));
5372                 pr_warn("failed to mkdir %s: %s\n", path, cp);
5373         }
5374         return err;
5375 }
5376
5377 static int check_path(const char *path)
5378 {
5379         char *cp, errmsg[STRERR_BUFSIZE];
5380         struct statfs st_fs;
5381         char *dname, *dir;
5382         int err = 0;
5383
5384         if (path == NULL)
5385                 return -EINVAL;
5386
5387         dname = strdup(path);
5388         if (dname == NULL)
5389                 return -ENOMEM;
5390
5391         dir = dirname(dname);
5392         if (statfs(dir, &st_fs)) {
5393                 cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg));
5394                 pr_warn("failed to statfs %s: %s\n", dir, cp);
5395                 err = -errno;
5396         }
5397         free(dname);
5398
5399         if (!err && st_fs.f_type != BPF_FS_MAGIC) {
5400                 pr_warn("specified path %s is not on BPF FS\n", path);
5401                 err = -EINVAL;
5402         }
5403
5404         return err;
5405 }
5406
5407 int bpf_program__pin_instance(struct bpf_program *prog, const char *path,
5408                               int instance)
5409 {
5410         char *cp, errmsg[STRERR_BUFSIZE];
5411         int err;
5412
5413         err = make_parent_dir(path);
5414         if (err)
5415                 return err;
5416
5417         err = check_path(path);
5418         if (err)
5419                 return err;
5420
5421         if (prog == NULL) {
5422                 pr_warn("invalid program pointer\n");
5423                 return -EINVAL;
5424         }
5425
5426         if (instance < 0 || instance >= prog->instances.nr) {
5427                 pr_warn("invalid prog instance %d of prog %s (max %d)\n",
5428                         instance, prog->section_name, prog->instances.nr);
5429                 return -EINVAL;
5430         }
5431
5432         if (bpf_obj_pin(prog->instances.fds[instance], path)) {
5433                 cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg));
5434                 pr_warn("failed to pin program: %s\n", cp);
5435                 return -errno;
5436         }
5437         pr_debug("pinned program '%s'\n", path);
5438
5439         return 0;
5440 }
5441
5442 int bpf_program__unpin_instance(struct bpf_program *prog, const char *path,
5443                                 int instance)
5444 {
5445         int err;
5446
5447         err = check_path(path);
5448         if (err)
5449                 return err;
5450
5451         if (prog == NULL) {
5452                 pr_warn("invalid program pointer\n");
5453                 return -EINVAL;
5454         }
5455
5456         if (instance < 0 || instance >= prog->instances.nr) {
5457                 pr_warn("invalid prog instance %d of prog %s (max %d)\n",
5458                         instance, prog->section_name, prog->instances.nr);
5459                 return -EINVAL;
5460         }
5461
5462         err = unlink(path);
5463         if (err != 0)
5464                 return -errno;
5465         pr_debug("unpinned program '%s'\n", path);
5466
5467         return 0;
5468 }
5469
5470 int bpf_program__pin(struct bpf_program *prog, const char *path)
5471 {
5472         int i, err;
5473
5474         err = make_parent_dir(path);
5475         if (err)
5476                 return err;
5477
5478         err = check_path(path);
5479         if (err)
5480                 return err;
5481
5482         if (prog == NULL) {
5483                 pr_warn("invalid program pointer\n");
5484                 return -EINVAL;
5485         }
5486
5487         if (prog->instances.nr <= 0) {
5488                 pr_warn("no instances of prog %s to pin\n",
5489                            prog->section_name);
5490                 return -EINVAL;
5491         }
5492
5493         if (prog->instances.nr == 1) {
5494                 /* don't create subdirs when pinning single instance */
5495                 return bpf_program__pin_instance(prog, path, 0);
5496         }
5497
5498         for (i = 0; i < prog->instances.nr; i++) {
5499                 char buf[PATH_MAX];
5500                 int len;
5501
5502                 len = snprintf(buf, PATH_MAX, "%s/%d", path, i);
5503                 if (len < 0) {
5504                         err = -EINVAL;
5505                         goto err_unpin;
5506                 } else if (len >= PATH_MAX) {
5507                         err = -ENAMETOOLONG;
5508                         goto err_unpin;
5509                 }
5510
5511                 err = bpf_program__pin_instance(prog, buf, i);
5512                 if (err)
5513                         goto err_unpin;
5514         }
5515
5516         return 0;
5517
5518 err_unpin:
5519         for (i = i - 1; i >= 0; i--) {
5520                 char buf[PATH_MAX];
5521                 int len;
5522
5523                 len = snprintf(buf, PATH_MAX, "%s/%d", path, i);
5524                 if (len < 0)
5525                         continue;
5526                 else if (len >= PATH_MAX)
5527                         continue;
5528
5529                 bpf_program__unpin_instance(prog, buf, i);
5530         }
5531
5532         rmdir(path);
5533
5534         return err;
5535 }
5536
5537 int bpf_program__unpin(struct bpf_program *prog, const char *path)
5538 {
5539         int i, err;
5540
5541         err = check_path(path);
5542         if (err)
5543                 return err;
5544
5545         if (prog == NULL) {
5546                 pr_warn("invalid program pointer\n");
5547                 return -EINVAL;
5548         }
5549
5550         if (prog->instances.nr <= 0) {
5551                 pr_warn("no instances of prog %s to pin\n",
5552                            prog->section_name);
5553                 return -EINVAL;
5554         }
5555
5556         if (prog->instances.nr == 1) {
5557                 /* don't create subdirs when pinning single instance */
5558                 return bpf_program__unpin_instance(prog, path, 0);
5559         }
5560
5561         for (i = 0; i < prog->instances.nr; i++) {
5562                 char buf[PATH_MAX];
5563                 int len;
5564
5565                 len = snprintf(buf, PATH_MAX, "%s/%d", path, i);
5566                 if (len < 0)
5567                         return -EINVAL;
5568                 else if (len >= PATH_MAX)
5569                         return -ENAMETOOLONG;
5570
5571                 err = bpf_program__unpin_instance(prog, buf, i);
5572                 if (err)
5573                         return err;
5574         }
5575
5576         err = rmdir(path);
5577         if (err)
5578                 return -errno;
5579
5580         return 0;
5581 }
5582
5583 int bpf_map__pin(struct bpf_map *map, const char *path)
5584 {
5585         char *cp, errmsg[STRERR_BUFSIZE];
5586         int err;
5587
5588         if (map == NULL) {
5589                 pr_warn("invalid map pointer\n");
5590                 return -EINVAL;
5591         }
5592
5593         if (map->pin_path) {
5594                 if (path && strcmp(path, map->pin_path)) {
5595                         pr_warn("map '%s' already has pin path '%s' different from '%s'\n",
5596                                 bpf_map__name(map), map->pin_path, path);
5597                         return -EINVAL;
5598                 } else if (map->pinned) {
5599                         pr_debug("map '%s' already pinned at '%s'; not re-pinning\n",
5600                                  bpf_map__name(map), map->pin_path);
5601                         return 0;
5602                 }
5603         } else {
5604                 if (!path) {
5605                         pr_warn("missing a path to pin map '%s' at\n",
5606                                 bpf_map__name(map));
5607                         return -EINVAL;
5608                 } else if (map->pinned) {
5609                         pr_warn("map '%s' already pinned\n", bpf_map__name(map));
5610                         return -EEXIST;
5611                 }
5612
5613                 map->pin_path = strdup(path);
5614                 if (!map->pin_path) {
5615                         err = -errno;
5616                         goto out_err;
5617                 }
5618         }
5619
5620         err = make_parent_dir(map->pin_path);
5621         if (err)
5622                 return err;
5623
5624         err = check_path(map->pin_path);
5625         if (err)
5626                 return err;
5627
5628         if (bpf_obj_pin(map->fd, map->pin_path)) {
5629                 err = -errno;
5630                 goto out_err;
5631         }
5632
5633         map->pinned = true;
5634         pr_debug("pinned map '%s'\n", map->pin_path);
5635
5636         return 0;
5637
5638 out_err:
5639         cp = libbpf_strerror_r(-err, errmsg, sizeof(errmsg));
5640         pr_warn("failed to pin map: %s\n", cp);
5641         return err;
5642 }
5643
5644 int bpf_map__unpin(struct bpf_map *map, const char *path)
5645 {
5646         int err;
5647
5648         if (map == NULL) {
5649                 pr_warn("invalid map pointer\n");
5650                 return -EINVAL;
5651         }
5652
5653         if (map->pin_path) {
5654                 if (path && strcmp(path, map->pin_path)) {
5655                         pr_warn("map '%s' already has pin path '%s' different from '%s'\n",
5656                                 bpf_map__name(map), map->pin_path, path);
5657                         return -EINVAL;
5658                 }
5659                 path = map->pin_path;
5660         } else if (!path) {
5661                 pr_warn("no path to unpin map '%s' from\n",
5662                         bpf_map__name(map));
5663                 return -EINVAL;
5664         }
5665
5666         err = check_path(path);
5667         if (err)
5668                 return err;
5669
5670         err = unlink(path);
5671         if (err != 0)
5672                 return -errno;
5673
5674         map->pinned = false;
5675         pr_debug("unpinned map '%s' from '%s'\n", bpf_map__name(map), path);
5676
5677         return 0;
5678 }
5679
5680 int bpf_map__set_pin_path(struct bpf_map *map, const char *path)
5681 {
5682         char *new = NULL;
5683
5684         if (path) {
5685                 new = strdup(path);
5686                 if (!new)
5687                         return -errno;
5688         }
5689
5690         free(map->pin_path);
5691         map->pin_path = new;
5692         return 0;
5693 }
5694
5695 const char *bpf_map__get_pin_path(const struct bpf_map *map)
5696 {
5697         return map->pin_path;
5698 }
5699
5700 bool bpf_map__is_pinned(const struct bpf_map *map)
5701 {
5702         return map->pinned;
5703 }
5704
5705 int bpf_object__pin_maps(struct bpf_object *obj, const char *path)
5706 {
5707         struct bpf_map *map;
5708         int err;
5709
5710         if (!obj)
5711                 return -ENOENT;
5712
5713         if (!obj->loaded) {
5714                 pr_warn("object not yet loaded; load it first\n");
5715                 return -ENOENT;
5716         }
5717
5718         bpf_object__for_each_map(map, obj) {
5719                 char *pin_path = NULL;
5720                 char buf[PATH_MAX];
5721
5722                 if (path) {
5723                         int len;
5724
5725                         len = snprintf(buf, PATH_MAX, "%s/%s", path,
5726                                        bpf_map__name(map));
5727                         if (len < 0) {
5728                                 err = -EINVAL;
5729                                 goto err_unpin_maps;
5730                         } else if (len >= PATH_MAX) {
5731                                 err = -ENAMETOOLONG;
5732                                 goto err_unpin_maps;
5733                         }
5734                         pin_path = buf;
5735                 } else if (!map->pin_path) {
5736                         continue;
5737                 }
5738
5739                 err = bpf_map__pin(map, pin_path);
5740                 if (err)
5741                         goto err_unpin_maps;
5742         }
5743
5744         return 0;
5745
5746 err_unpin_maps:
5747         while ((map = bpf_map__prev(map, obj))) {
5748                 if (!map->pin_path)
5749                         continue;
5750
5751                 bpf_map__unpin(map, NULL);
5752         }
5753
5754         return err;
5755 }
5756
5757 int bpf_object__unpin_maps(struct bpf_object *obj, const char *path)
5758 {
5759         struct bpf_map *map;
5760         int err;
5761
5762         if (!obj)
5763                 return -ENOENT;
5764
5765         bpf_object__for_each_map(map, obj) {
5766                 char *pin_path = NULL;
5767                 char buf[PATH_MAX];
5768
5769                 if (path) {
5770                         int len;
5771
5772                         len = snprintf(buf, PATH_MAX, "%s/%s", path,
5773                                        bpf_map__name(map));
5774                         if (len < 0)
5775                                 return -EINVAL;
5776                         else if (len >= PATH_MAX)
5777                                 return -ENAMETOOLONG;
5778                         pin_path = buf;
5779                 } else if (!map->pin_path) {
5780                         continue;
5781                 }
5782
5783                 err = bpf_map__unpin(map, pin_path);
5784                 if (err)
5785                         return err;
5786         }
5787
5788         return 0;
5789 }
5790
5791 int bpf_object__pin_programs(struct bpf_object *obj, const char *path)
5792 {
5793         struct bpf_program *prog;
5794         int err;
5795
5796         if (!obj)
5797                 return -ENOENT;
5798
5799         if (!obj->loaded) {
5800                 pr_warn("object not yet loaded; load it first\n");
5801                 return -ENOENT;
5802         }
5803
5804         bpf_object__for_each_program(prog, obj) {
5805                 char buf[PATH_MAX];
5806                 int len;
5807
5808                 len = snprintf(buf, PATH_MAX, "%s/%s", path,
5809                                prog->pin_name);
5810                 if (len < 0) {
5811                         err = -EINVAL;
5812                         goto err_unpin_programs;
5813                 } else if (len >= PATH_MAX) {
5814                         err = -ENAMETOOLONG;
5815                         goto err_unpin_programs;
5816                 }
5817
5818                 err = bpf_program__pin(prog, buf);
5819                 if (err)
5820                         goto err_unpin_programs;
5821         }
5822
5823         return 0;
5824
5825 err_unpin_programs:
5826         while ((prog = bpf_program__prev(prog, obj))) {
5827                 char buf[PATH_MAX];
5828                 int len;
5829
5830                 len = snprintf(buf, PATH_MAX, "%s/%s", path,
5831                                prog->pin_name);
5832                 if (len < 0)
5833                         continue;
5834                 else if (len >= PATH_MAX)
5835                         continue;
5836
5837                 bpf_program__unpin(prog, buf);
5838         }
5839
5840         return err;
5841 }
5842
5843 int bpf_object__unpin_programs(struct bpf_object *obj, const char *path)
5844 {
5845         struct bpf_program *prog;
5846         int err;
5847
5848         if (!obj)
5849                 return -ENOENT;
5850
5851         bpf_object__for_each_program(prog, obj) {
5852                 char buf[PATH_MAX];
5853                 int len;
5854
5855                 len = snprintf(buf, PATH_MAX, "%s/%s", path,
5856                                prog->pin_name);
5857                 if (len < 0)
5858                         return -EINVAL;
5859                 else if (len >= PATH_MAX)
5860                         return -ENAMETOOLONG;
5861
5862                 err = bpf_program__unpin(prog, buf);
5863                 if (err)
5864                         return err;
5865         }
5866
5867         return 0;
5868 }
5869
5870 int bpf_object__pin(struct bpf_object *obj, const char *path)
5871 {
5872         int err;
5873
5874         err = bpf_object__pin_maps(obj, path);
5875         if (err)
5876                 return err;
5877
5878         err = bpf_object__pin_programs(obj, path);
5879         if (err) {
5880                 bpf_object__unpin_maps(obj, path);
5881                 return err;
5882         }
5883
5884         return 0;
5885 }
5886
5887 void bpf_object__close(struct bpf_object *obj)
5888 {
5889         size_t i;
5890
5891         if (!obj)
5892                 return;
5893
5894         if (obj->clear_priv)
5895                 obj->clear_priv(obj, obj->priv);
5896
5897         bpf_object__elf_finish(obj);
5898         bpf_object__unload(obj);
5899         btf__free(obj->btf);
5900         btf_ext__free(obj->btf_ext);
5901
5902         for (i = 0; i < obj->nr_maps; i++) {
5903                 struct bpf_map *map = &obj->maps[i];
5904
5905                 if (map->clear_priv)
5906                         map->clear_priv(map, map->priv);
5907                 map->priv = NULL;
5908                 map->clear_priv = NULL;
5909
5910                 if (map->mmaped) {
5911                         munmap(map->mmaped, bpf_map_mmap_sz(map));
5912                         map->mmaped = NULL;
5913                 }
5914
5915                 if (map->st_ops) {
5916                         zfree(&map->st_ops->data);
5917                         zfree(&map->st_ops->progs);
5918                         zfree(&map->st_ops->kern_func_off);
5919                         zfree(&map->st_ops);
5920                 }
5921
5922                 zfree(&map->name);
5923                 zfree(&map->pin_path);
5924         }
5925
5926         zfree(&obj->kconfig);
5927         zfree(&obj->externs);
5928         obj->nr_extern = 0;
5929
5930         zfree(&obj->maps);
5931         obj->nr_maps = 0;
5932
5933         if (obj->programs && obj->nr_programs) {
5934                 for (i = 0; i < obj->nr_programs; i++)
5935                         bpf_program__exit(&obj->programs[i]);
5936         }
5937         zfree(&obj->programs);
5938
5939         list_del(&obj->list);
5940         free(obj);
5941 }
5942
5943 struct bpf_object *
5944 bpf_object__next(struct bpf_object *prev)
5945 {
5946         struct bpf_object *next;
5947
5948         if (!prev)
5949                 next = list_first_entry(&bpf_objects_list,
5950                                         struct bpf_object,
5951                                         list);
5952         else
5953                 next = list_next_entry(prev, list);
5954
5955         /* Empty list is noticed here so don't need checking on entry. */
5956         if (&next->list == &bpf_objects_list)
5957                 return NULL;
5958
5959         return next;
5960 }
5961
5962 const char *bpf_object__name(const struct bpf_object *obj)
5963 {
5964         return obj ? obj->name : ERR_PTR(-EINVAL);
5965 }
5966
5967 unsigned int bpf_object__kversion(const struct bpf_object *obj)
5968 {
5969         return obj ? obj->kern_version : 0;
5970 }
5971
5972 struct btf *bpf_object__btf(const struct bpf_object *obj)
5973 {
5974         return obj ? obj->btf : NULL;
5975 }
5976
5977 int bpf_object__btf_fd(const struct bpf_object *obj)
5978 {
5979         return obj->btf ? btf__fd(obj->btf) : -1;
5980 }
5981
5982 int bpf_object__set_priv(struct bpf_object *obj, void *priv,
5983                          bpf_object_clear_priv_t clear_priv)
5984 {
5985         if (obj->priv && obj->clear_priv)
5986                 obj->clear_priv(obj, obj->priv);
5987
5988         obj->priv = priv;
5989         obj->clear_priv = clear_priv;
5990         return 0;
5991 }
5992
5993 void *bpf_object__priv(const struct bpf_object *obj)
5994 {
5995         return obj ? obj->priv : ERR_PTR(-EINVAL);
5996 }
5997
5998 static struct bpf_program *
5999 __bpf_program__iter(const struct bpf_program *p, const struct bpf_object *obj,
6000                     bool forward)
6001 {
6002         size_t nr_programs = obj->nr_programs;
6003         ssize_t idx;
6004
6005         if (!nr_programs)
6006                 return NULL;
6007
6008         if (!p)
6009                 /* Iter from the beginning */
6010                 return forward ? &obj->programs[0] :
6011                         &obj->programs[nr_programs - 1];
6012
6013         if (p->obj != obj) {
6014                 pr_warn("error: program handler doesn't match object\n");
6015                 return NULL;
6016         }
6017
6018         idx = (p - obj->programs) + (forward ? 1 : -1);
6019         if (idx >= obj->nr_programs || idx < 0)
6020                 return NULL;
6021         return &obj->programs[idx];
6022 }
6023
6024 struct bpf_program *
6025 bpf_program__next(struct bpf_program *prev, const struct bpf_object *obj)
6026 {
6027         struct bpf_program *prog = prev;
6028
6029         do {
6030                 prog = __bpf_program__iter(prog, obj, true);
6031         } while (prog && bpf_program__is_function_storage(prog, obj));
6032
6033         return prog;
6034 }
6035
6036 struct bpf_program *
6037 bpf_program__prev(struct bpf_program *next, const struct bpf_object *obj)
6038 {
6039         struct bpf_program *prog = next;
6040
6041         do {
6042                 prog = __bpf_program__iter(prog, obj, false);
6043         } while (prog && bpf_program__is_function_storage(prog, obj));
6044
6045         return prog;
6046 }
6047
6048 int bpf_program__set_priv(struct bpf_program *prog, void *priv,
6049                           bpf_program_clear_priv_t clear_priv)
6050 {
6051         if (prog->priv && prog->clear_priv)
6052                 prog->clear_priv(prog, prog->priv);
6053
6054         prog->priv = priv;
6055         prog->clear_priv = clear_priv;
6056         return 0;
6057 }
6058
6059 void *bpf_program__priv(const struct bpf_program *prog)
6060 {
6061         return prog ? prog->priv : ERR_PTR(-EINVAL);
6062 }
6063
6064 void bpf_program__set_ifindex(struct bpf_program *prog, __u32 ifindex)
6065 {
6066         prog->prog_ifindex = ifindex;
6067 }
6068
6069 const char *bpf_program__name(const struct bpf_program *prog)
6070 {
6071         return prog->name;
6072 }
6073
6074 const char *bpf_program__title(const struct bpf_program *prog, bool needs_copy)
6075 {
6076         const char *title;
6077
6078         title = prog->section_name;
6079         if (needs_copy) {
6080                 title = strdup(title);
6081                 if (!title) {
6082                         pr_warn("failed to strdup program title\n");
6083                         return ERR_PTR(-ENOMEM);
6084                 }
6085         }
6086
6087         return title;
6088 }
6089
6090 int bpf_program__fd(const struct bpf_program *prog)
6091 {
6092         return bpf_program__nth_fd(prog, 0);
6093 }
6094
6095 size_t bpf_program__size(const struct bpf_program *prog)
6096 {
6097         return prog->insns_cnt * sizeof(struct bpf_insn);
6098 }
6099
6100 int bpf_program__set_prep(struct bpf_program *prog, int nr_instances,
6101                           bpf_program_prep_t prep)
6102 {
6103         int *instances_fds;
6104
6105         if (nr_instances <= 0 || !prep)
6106                 return -EINVAL;
6107
6108         if (prog->instances.nr > 0 || prog->instances.fds) {
6109                 pr_warn("Can't set pre-processor after loading\n");
6110                 return -EINVAL;
6111         }
6112
6113         instances_fds = malloc(sizeof(int) * nr_instances);
6114         if (!instances_fds) {
6115                 pr_warn("alloc memory failed for fds\n");
6116                 return -ENOMEM;
6117         }
6118
6119         /* fill all fd with -1 */
6120         memset(instances_fds, -1, sizeof(int) * nr_instances);
6121
6122         prog->instances.nr = nr_instances;
6123         prog->instances.fds = instances_fds;
6124         prog->preprocessor = prep;
6125         return 0;
6126 }
6127
6128 int bpf_program__nth_fd(const struct bpf_program *prog, int n)
6129 {
6130         int fd;
6131
6132         if (!prog)
6133                 return -EINVAL;
6134
6135         if (n >= prog->instances.nr || n < 0) {
6136                 pr_warn("Can't get the %dth fd from program %s: only %d instances\n",
6137                         n, prog->section_name, prog->instances.nr);
6138                 return -EINVAL;
6139         }
6140
6141         fd = prog->instances.fds[n];
6142         if (fd < 0) {
6143                 pr_warn("%dth instance of program '%s' is invalid\n",
6144                         n, prog->section_name);
6145                 return -ENOENT;
6146         }
6147
6148         return fd;
6149 }
6150
6151 enum bpf_prog_type bpf_program__get_type(struct bpf_program *prog)
6152 {
6153         return prog->type;
6154 }
6155
6156 void bpf_program__set_type(struct bpf_program *prog, enum bpf_prog_type type)
6157 {
6158         prog->type = type;
6159 }
6160
6161 static bool bpf_program__is_type(const struct bpf_program *prog,
6162                                  enum bpf_prog_type type)
6163 {
6164         return prog ? (prog->type == type) : false;
6165 }
6166
6167 #define BPF_PROG_TYPE_FNS(NAME, TYPE)                           \
6168 int bpf_program__set_##NAME(struct bpf_program *prog)           \
6169 {                                                               \
6170         if (!prog)                                              \
6171                 return -EINVAL;                                 \
6172         bpf_program__set_type(prog, TYPE);                      \
6173         return 0;                                               \
6174 }                                                               \
6175                                                                 \
6176 bool bpf_program__is_##NAME(const struct bpf_program *prog)     \
6177 {                                                               \
6178         return bpf_program__is_type(prog, TYPE);                \
6179 }                                                               \
6180
6181 BPF_PROG_TYPE_FNS(socket_filter, BPF_PROG_TYPE_SOCKET_FILTER);
6182 BPF_PROG_TYPE_FNS(kprobe, BPF_PROG_TYPE_KPROBE);
6183 BPF_PROG_TYPE_FNS(sched_cls, BPF_PROG_TYPE_SCHED_CLS);
6184 BPF_PROG_TYPE_FNS(sched_act, BPF_PROG_TYPE_SCHED_ACT);
6185 BPF_PROG_TYPE_FNS(tracepoint, BPF_PROG_TYPE_TRACEPOINT);
6186 BPF_PROG_TYPE_FNS(raw_tracepoint, BPF_PROG_TYPE_RAW_TRACEPOINT);
6187 BPF_PROG_TYPE_FNS(xdp, BPF_PROG_TYPE_XDP);
6188 BPF_PROG_TYPE_FNS(perf_event, BPF_PROG_TYPE_PERF_EVENT);
6189 BPF_PROG_TYPE_FNS(tracing, BPF_PROG_TYPE_TRACING);
6190 BPF_PROG_TYPE_FNS(struct_ops, BPF_PROG_TYPE_STRUCT_OPS);
6191 BPF_PROG_TYPE_FNS(extension, BPF_PROG_TYPE_EXT);
6192
6193 enum bpf_attach_type
6194 bpf_program__get_expected_attach_type(struct bpf_program *prog)
6195 {
6196         return prog->expected_attach_type;
6197 }
6198
6199 void bpf_program__set_expected_attach_type(struct bpf_program *prog,
6200                                            enum bpf_attach_type type)
6201 {
6202         prog->expected_attach_type = type;
6203 }
6204
6205 #define BPF_PROG_SEC_IMPL(string, ptype, eatype, is_attachable, btf, atype) \
6206         { string, sizeof(string) - 1, ptype, eatype, is_attachable, btf, atype }
6207
6208 /* Programs that can NOT be attached. */
6209 #define BPF_PROG_SEC(string, ptype) BPF_PROG_SEC_IMPL(string, ptype, 0, 0, 0, 0)
6210
6211 /* Programs that can be attached. */
6212 #define BPF_APROG_SEC(string, ptype, atype) \
6213         BPF_PROG_SEC_IMPL(string, ptype, 0, 1, 0, atype)
6214
6215 /* Programs that must specify expected attach type at load time. */
6216 #define BPF_EAPROG_SEC(string, ptype, eatype) \
6217         BPF_PROG_SEC_IMPL(string, ptype, eatype, 1, 0, eatype)
6218
6219 /* Programs that use BTF to identify attach point */
6220 #define BPF_PROG_BTF(string, ptype, eatype) \
6221         BPF_PROG_SEC_IMPL(string, ptype, eatype, 0, 1, 0)
6222
6223 /* Programs that can be attached but attach type can't be identified by section
6224  * name. Kept for backward compatibility.
6225  */
6226 #define BPF_APROG_COMPAT(string, ptype) BPF_PROG_SEC(string, ptype)
6227
6228 #define SEC_DEF(sec_pfx, ptype, ...) {                                      \
6229         .sec = sec_pfx,                                                     \
6230         .len = sizeof(sec_pfx) - 1,                                         \
6231         .prog_type = BPF_PROG_TYPE_##ptype,                                 \
6232         __VA_ARGS__                                                         \
6233 }
6234
6235 struct bpf_sec_def;
6236
6237 typedef struct bpf_link *(*attach_fn_t)(const struct bpf_sec_def *sec,
6238                                         struct bpf_program *prog);
6239
6240 static struct bpf_link *attach_kprobe(const struct bpf_sec_def *sec,
6241                                       struct bpf_program *prog);
6242 static struct bpf_link *attach_tp(const struct bpf_sec_def *sec,
6243                                   struct bpf_program *prog);
6244 static struct bpf_link *attach_raw_tp(const struct bpf_sec_def *sec,
6245                                       struct bpf_program *prog);
6246 static struct bpf_link *attach_trace(const struct bpf_sec_def *sec,
6247                                      struct bpf_program *prog);
6248
6249 struct bpf_sec_def {
6250         const char *sec;
6251         size_t len;
6252         enum bpf_prog_type prog_type;
6253         enum bpf_attach_type expected_attach_type;
6254         bool is_attachable;
6255         bool is_attach_btf;
6256         enum bpf_attach_type attach_type;
6257         attach_fn_t attach_fn;
6258 };
6259
6260 static const struct bpf_sec_def section_defs[] = {
6261         BPF_PROG_SEC("socket",                  BPF_PROG_TYPE_SOCKET_FILTER),
6262         BPF_PROG_SEC("sk_reuseport",            BPF_PROG_TYPE_SK_REUSEPORT),
6263         SEC_DEF("kprobe/", KPROBE,
6264                 .attach_fn = attach_kprobe),
6265         BPF_PROG_SEC("uprobe/",                 BPF_PROG_TYPE_KPROBE),
6266         SEC_DEF("kretprobe/", KPROBE,
6267                 .attach_fn = attach_kprobe),
6268         BPF_PROG_SEC("uretprobe/",              BPF_PROG_TYPE_KPROBE),
6269         BPF_PROG_SEC("classifier",              BPF_PROG_TYPE_SCHED_CLS),
6270         BPF_PROG_SEC("action",                  BPF_PROG_TYPE_SCHED_ACT),
6271         SEC_DEF("tracepoint/", TRACEPOINT,
6272                 .attach_fn = attach_tp),
6273         SEC_DEF("tp/", TRACEPOINT,
6274                 .attach_fn = attach_tp),
6275         SEC_DEF("raw_tracepoint/", RAW_TRACEPOINT,
6276                 .attach_fn = attach_raw_tp),
6277         SEC_DEF("raw_tp/", RAW_TRACEPOINT,
6278                 .attach_fn = attach_raw_tp),
6279         SEC_DEF("tp_btf/", TRACING,
6280                 .expected_attach_type = BPF_TRACE_RAW_TP,
6281                 .is_attach_btf = true,
6282                 .attach_fn = attach_trace),
6283         SEC_DEF("fentry/", TRACING,
6284                 .expected_attach_type = BPF_TRACE_FENTRY,
6285                 .is_attach_btf = true,
6286                 .attach_fn = attach_trace),
6287         SEC_DEF("fexit/", TRACING,
6288                 .expected_attach_type = BPF_TRACE_FEXIT,
6289                 .is_attach_btf = true,
6290                 .attach_fn = attach_trace),
6291         SEC_DEF("freplace/", EXT,
6292                 .is_attach_btf = true,
6293                 .attach_fn = attach_trace),
6294         BPF_PROG_SEC("xdp",                     BPF_PROG_TYPE_XDP),
6295         BPF_PROG_SEC("perf_event",              BPF_PROG_TYPE_PERF_EVENT),
6296         BPF_PROG_SEC("lwt_in",                  BPF_PROG_TYPE_LWT_IN),
6297         BPF_PROG_SEC("lwt_out",                 BPF_PROG_TYPE_LWT_OUT),
6298         BPF_PROG_SEC("lwt_xmit",                BPF_PROG_TYPE_LWT_XMIT),
6299         BPF_PROG_SEC("lwt_seg6local",           BPF_PROG_TYPE_LWT_SEG6LOCAL),
6300         BPF_APROG_SEC("cgroup_skb/ingress",     BPF_PROG_TYPE_CGROUP_SKB,
6301                                                 BPF_CGROUP_INET_INGRESS),
6302         BPF_APROG_SEC("cgroup_skb/egress",      BPF_PROG_TYPE_CGROUP_SKB,
6303                                                 BPF_CGROUP_INET_EGRESS),
6304         BPF_APROG_COMPAT("cgroup/skb",          BPF_PROG_TYPE_CGROUP_SKB),
6305         BPF_APROG_SEC("cgroup/sock",            BPF_PROG_TYPE_CGROUP_SOCK,
6306                                                 BPF_CGROUP_INET_SOCK_CREATE),
6307         BPF_EAPROG_SEC("cgroup/post_bind4",     BPF_PROG_TYPE_CGROUP_SOCK,
6308                                                 BPF_CGROUP_INET4_POST_BIND),
6309         BPF_EAPROG_SEC("cgroup/post_bind6",     BPF_PROG_TYPE_CGROUP_SOCK,
6310                                                 BPF_CGROUP_INET6_POST_BIND),
6311         BPF_APROG_SEC("cgroup/dev",             BPF_PROG_TYPE_CGROUP_DEVICE,
6312                                                 BPF_CGROUP_DEVICE),
6313         BPF_APROG_SEC("sockops",                BPF_PROG_TYPE_SOCK_OPS,
6314                                                 BPF_CGROUP_SOCK_OPS),
6315         BPF_APROG_SEC("sk_skb/stream_parser",   BPF_PROG_TYPE_SK_SKB,
6316                                                 BPF_SK_SKB_STREAM_PARSER),
6317         BPF_APROG_SEC("sk_skb/stream_verdict",  BPF_PROG_TYPE_SK_SKB,
6318                                                 BPF_SK_SKB_STREAM_VERDICT),
6319         BPF_APROG_COMPAT("sk_skb",              BPF_PROG_TYPE_SK_SKB),
6320         BPF_APROG_SEC("sk_msg",                 BPF_PROG_TYPE_SK_MSG,
6321                                                 BPF_SK_MSG_VERDICT),
6322         BPF_APROG_SEC("lirc_mode2",             BPF_PROG_TYPE_LIRC_MODE2,
6323                                                 BPF_LIRC_MODE2),
6324         BPF_APROG_SEC("flow_dissector",         BPF_PROG_TYPE_FLOW_DISSECTOR,
6325                                                 BPF_FLOW_DISSECTOR),
6326         BPF_EAPROG_SEC("cgroup/bind4",          BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
6327                                                 BPF_CGROUP_INET4_BIND),
6328         BPF_EAPROG_SEC("cgroup/bind6",          BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
6329                                                 BPF_CGROUP_INET6_BIND),
6330         BPF_EAPROG_SEC("cgroup/connect4",       BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
6331                                                 BPF_CGROUP_INET4_CONNECT),
6332         BPF_EAPROG_SEC("cgroup/connect6",       BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
6333                                                 BPF_CGROUP_INET6_CONNECT),
6334         BPF_EAPROG_SEC("cgroup/sendmsg4",       BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
6335                                                 BPF_CGROUP_UDP4_SENDMSG),
6336         BPF_EAPROG_SEC("cgroup/sendmsg6",       BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
6337                                                 BPF_CGROUP_UDP6_SENDMSG),
6338         BPF_EAPROG_SEC("cgroup/recvmsg4",       BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
6339                                                 BPF_CGROUP_UDP4_RECVMSG),
6340         BPF_EAPROG_SEC("cgroup/recvmsg6",       BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
6341                                                 BPF_CGROUP_UDP6_RECVMSG),
6342         BPF_EAPROG_SEC("cgroup/sysctl",         BPF_PROG_TYPE_CGROUP_SYSCTL,
6343                                                 BPF_CGROUP_SYSCTL),
6344         BPF_EAPROG_SEC("cgroup/getsockopt",     BPF_PROG_TYPE_CGROUP_SOCKOPT,
6345                                                 BPF_CGROUP_GETSOCKOPT),
6346         BPF_EAPROG_SEC("cgroup/setsockopt",     BPF_PROG_TYPE_CGROUP_SOCKOPT,
6347                                                 BPF_CGROUP_SETSOCKOPT),
6348         BPF_PROG_SEC("struct_ops",              BPF_PROG_TYPE_STRUCT_OPS),
6349 };
6350
6351 #undef BPF_PROG_SEC_IMPL
6352 #undef BPF_PROG_SEC
6353 #undef BPF_APROG_SEC
6354 #undef BPF_EAPROG_SEC
6355 #undef BPF_APROG_COMPAT
6356 #undef SEC_DEF
6357
6358 #define MAX_TYPE_NAME_SIZE 32
6359
6360 static const struct bpf_sec_def *find_sec_def(const char *sec_name)
6361 {
6362         int i, n = ARRAY_SIZE(section_defs);
6363
6364         for (i = 0; i < n; i++) {
6365                 if (strncmp(sec_name,
6366                             section_defs[i].sec, section_defs[i].len))
6367                         continue;
6368                 return &section_defs[i];
6369         }
6370         return NULL;
6371 }
6372
6373 static char *libbpf_get_type_names(bool attach_type)
6374 {
6375         int i, len = ARRAY_SIZE(section_defs) * MAX_TYPE_NAME_SIZE;
6376         char *buf;
6377
6378         buf = malloc(len);
6379         if (!buf)
6380                 return NULL;
6381
6382         buf[0] = '\0';
6383         /* Forge string buf with all available names */
6384         for (i = 0; i < ARRAY_SIZE(section_defs); i++) {
6385                 if (attach_type && !section_defs[i].is_attachable)
6386                         continue;
6387
6388                 if (strlen(buf) + strlen(section_defs[i].sec) + 2 > len) {
6389                         free(buf);
6390                         return NULL;
6391                 }
6392                 strcat(buf, " ");
6393                 strcat(buf, section_defs[i].sec);
6394         }
6395
6396         return buf;
6397 }
6398
6399 int libbpf_prog_type_by_name(const char *name, enum bpf_prog_type *prog_type,
6400                              enum bpf_attach_type *expected_attach_type)
6401 {
6402         const struct bpf_sec_def *sec_def;
6403         char *type_names;
6404
6405         if (!name)
6406                 return -EINVAL;
6407
6408         sec_def = find_sec_def(name);
6409         if (sec_def) {
6410                 *prog_type = sec_def->prog_type;
6411                 *expected_attach_type = sec_def->expected_attach_type;
6412                 return 0;
6413         }
6414
6415         pr_debug("failed to guess program type from ELF section '%s'\n", name);
6416         type_names = libbpf_get_type_names(false);
6417         if (type_names != NULL) {
6418                 pr_debug("supported section(type) names are:%s\n", type_names);
6419                 free(type_names);
6420         }
6421
6422         return -ESRCH;
6423 }
6424
6425 static struct bpf_map *find_struct_ops_map_by_offset(struct bpf_object *obj,
6426                                                      size_t offset)
6427 {
6428         struct bpf_map *map;
6429         size_t i;
6430
6431         for (i = 0; i < obj->nr_maps; i++) {
6432                 map = &obj->maps[i];
6433                 if (!bpf_map__is_struct_ops(map))
6434                         continue;
6435                 if (map->sec_offset <= offset &&
6436                     offset - map->sec_offset < map->def.value_size)
6437                         return map;
6438         }
6439
6440         return NULL;
6441 }
6442
6443 /* Collect the reloc from ELF and populate the st_ops->progs[] */
6444 static int bpf_object__collect_struct_ops_map_reloc(struct bpf_object *obj,
6445                                                     GElf_Shdr *shdr,
6446                                                     Elf_Data *data)
6447 {
6448         const struct btf_member *member;
6449         struct bpf_struct_ops *st_ops;
6450         struct bpf_program *prog;
6451         unsigned int shdr_idx;
6452         const struct btf *btf;
6453         struct bpf_map *map;
6454         Elf_Data *symbols;
6455         unsigned int moff;
6456         const char *name;
6457         __u32 member_idx;
6458         GElf_Sym sym;
6459         GElf_Rel rel;
6460         int i, nrels;
6461
6462         symbols = obj->efile.symbols;
6463         btf = obj->btf;
6464         nrels = shdr->sh_size / shdr->sh_entsize;
6465         for (i = 0; i < nrels; i++) {
6466                 if (!gelf_getrel(data, i, &rel)) {
6467                         pr_warn("struct_ops reloc: failed to get %d reloc\n", i);
6468                         return -LIBBPF_ERRNO__FORMAT;
6469                 }
6470
6471                 if (!gelf_getsym(symbols, GELF_R_SYM(rel.r_info), &sym)) {
6472                         pr_warn("struct_ops reloc: symbol %zx not found\n",
6473                                 (size_t)GELF_R_SYM(rel.r_info));
6474                         return -LIBBPF_ERRNO__FORMAT;
6475                 }
6476
6477                 name = elf_strptr(obj->efile.elf, obj->efile.strtabidx,
6478                                   sym.st_name) ? : "<?>";
6479                 map = find_struct_ops_map_by_offset(obj, rel.r_offset);
6480                 if (!map) {
6481                         pr_warn("struct_ops reloc: cannot find map at rel.r_offset %zu\n",
6482                                 (size_t)rel.r_offset);
6483                         return -EINVAL;
6484                 }
6485
6486                 moff = rel.r_offset - map->sec_offset;
6487                 shdr_idx = sym.st_shndx;
6488                 st_ops = map->st_ops;
6489                 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",
6490                          map->name,
6491                          (long long)(rel.r_info >> 32),
6492                          (long long)sym.st_value,
6493                          shdr_idx, (size_t)rel.r_offset,
6494                          map->sec_offset, sym.st_name, name);
6495
6496                 if (shdr_idx >= SHN_LORESERVE) {
6497                         pr_warn("struct_ops reloc %s: rel.r_offset %zu shdr_idx %u unsupported non-static function\n",
6498                                 map->name, (size_t)rel.r_offset, shdr_idx);
6499                         return -LIBBPF_ERRNO__RELOC;
6500                 }
6501
6502                 member = find_member_by_offset(st_ops->type, moff * 8);
6503                 if (!member) {
6504                         pr_warn("struct_ops reloc %s: cannot find member at moff %u\n",
6505                                 map->name, moff);
6506                         return -EINVAL;
6507                 }
6508                 member_idx = member - btf_members(st_ops->type);
6509                 name = btf__name_by_offset(btf, member->name_off);
6510
6511                 if (!resolve_func_ptr(btf, member->type, NULL)) {
6512                         pr_warn("struct_ops reloc %s: cannot relocate non func ptr %s\n",
6513                                 map->name, name);
6514                         return -EINVAL;
6515                 }
6516
6517                 prog = bpf_object__find_prog_by_idx(obj, shdr_idx);
6518                 if (!prog) {
6519                         pr_warn("struct_ops reloc %s: cannot find prog at shdr_idx %u to relocate func ptr %s\n",
6520                                 map->name, shdr_idx, name);
6521                         return -EINVAL;
6522                 }
6523
6524                 if (prog->type == BPF_PROG_TYPE_UNSPEC) {
6525                         const struct bpf_sec_def *sec_def;
6526
6527                         sec_def = find_sec_def(prog->section_name);
6528                         if (sec_def &&
6529                             sec_def->prog_type != BPF_PROG_TYPE_STRUCT_OPS) {
6530                                 /* for pr_warn */
6531                                 prog->type = sec_def->prog_type;
6532                                 goto invalid_prog;
6533                         }
6534
6535                         prog->type = BPF_PROG_TYPE_STRUCT_OPS;
6536                         prog->attach_btf_id = st_ops->type_id;
6537                         prog->expected_attach_type = member_idx;
6538                 } else if (prog->type != BPF_PROG_TYPE_STRUCT_OPS ||
6539                            prog->attach_btf_id != st_ops->type_id ||
6540                            prog->expected_attach_type != member_idx) {
6541                         goto invalid_prog;
6542                 }
6543                 st_ops->progs[member_idx] = prog;
6544         }
6545
6546         return 0;
6547
6548 invalid_prog:
6549         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",
6550                 map->name, prog->name, prog->section_name, prog->type,
6551                 prog->attach_btf_id, prog->expected_attach_type, name);
6552         return -EINVAL;
6553 }
6554
6555 #define BTF_TRACE_PREFIX "btf_trace_"
6556 #define BTF_MAX_NAME_SIZE 128
6557
6558 static int find_btf_by_prefix_kind(const struct btf *btf, const char *prefix,
6559                                    const char *name, __u32 kind)
6560 {
6561         char btf_type_name[BTF_MAX_NAME_SIZE];
6562         int ret;
6563
6564         ret = snprintf(btf_type_name, sizeof(btf_type_name),
6565                        "%s%s", prefix, name);
6566         /* snprintf returns the number of characters written excluding the
6567          * the terminating null. So, if >= BTF_MAX_NAME_SIZE are written, it
6568          * indicates truncation.
6569          */
6570         if (ret < 0 || ret >= sizeof(btf_type_name))
6571                 return -ENAMETOOLONG;
6572         return btf__find_by_name_kind(btf, btf_type_name, kind);
6573 }
6574
6575 static inline int __find_vmlinux_btf_id(struct btf *btf, const char *name,
6576                                         enum bpf_attach_type attach_type)
6577 {
6578         int err;
6579
6580         if (attach_type == BPF_TRACE_RAW_TP)
6581                 err = find_btf_by_prefix_kind(btf, BTF_TRACE_PREFIX, name,
6582                                               BTF_KIND_TYPEDEF);
6583         else
6584                 err = btf__find_by_name_kind(btf, name, BTF_KIND_FUNC);
6585
6586         return err;
6587 }
6588
6589 int libbpf_find_vmlinux_btf_id(const char *name,
6590                                enum bpf_attach_type attach_type)
6591 {
6592         struct btf *btf;
6593
6594         btf = libbpf_find_kernel_btf();
6595         if (IS_ERR(btf)) {
6596                 pr_warn("vmlinux BTF is not found\n");
6597                 return -EINVAL;
6598         }
6599
6600         return __find_vmlinux_btf_id(btf, name, attach_type);
6601 }
6602
6603 static int libbpf_find_prog_btf_id(const char *name, __u32 attach_prog_fd)
6604 {
6605         struct bpf_prog_info_linear *info_linear;
6606         struct bpf_prog_info *info;
6607         struct btf *btf = NULL;
6608         int err = -EINVAL;
6609
6610         info_linear = bpf_program__get_prog_info_linear(attach_prog_fd, 0);
6611         if (IS_ERR_OR_NULL(info_linear)) {
6612                 pr_warn("failed get_prog_info_linear for FD %d\n",
6613                         attach_prog_fd);
6614                 return -EINVAL;
6615         }
6616         info = &info_linear->info;
6617         if (!info->btf_id) {
6618                 pr_warn("The target program doesn't have BTF\n");
6619                 goto out;
6620         }
6621         if (btf__get_from_id(info->btf_id, &btf)) {
6622                 pr_warn("Failed to get BTF of the program\n");
6623                 goto out;
6624         }
6625         err = btf__find_by_name_kind(btf, name, BTF_KIND_FUNC);
6626         btf__free(btf);
6627         if (err <= 0) {
6628                 pr_warn("%s is not found in prog's BTF\n", name);
6629                 goto out;
6630         }
6631 out:
6632         free(info_linear);
6633         return err;
6634 }
6635
6636 static int libbpf_find_attach_btf_id(struct bpf_program *prog)
6637 {
6638         enum bpf_attach_type attach_type = prog->expected_attach_type;
6639         __u32 attach_prog_fd = prog->attach_prog_fd;
6640         const char *name = prog->section_name;
6641         int i, err;
6642
6643         if (!name)
6644                 return -EINVAL;
6645
6646         for (i = 0; i < ARRAY_SIZE(section_defs); i++) {
6647                 if (!section_defs[i].is_attach_btf)
6648                         continue;
6649                 if (strncmp(name, section_defs[i].sec, section_defs[i].len))
6650                         continue;
6651                 if (attach_prog_fd)
6652                         err = libbpf_find_prog_btf_id(name + section_defs[i].len,
6653                                                       attach_prog_fd);
6654                 else
6655                         err = __find_vmlinux_btf_id(prog->obj->btf_vmlinux,
6656                                                     name + section_defs[i].len,
6657                                                     attach_type);
6658                 if (err <= 0)
6659                         pr_warn("%s is not found in vmlinux BTF\n", name);
6660                 return err;
6661         }
6662         pr_warn("failed to identify btf_id based on ELF section name '%s'\n", name);
6663         return -ESRCH;
6664 }
6665
6666 int libbpf_attach_type_by_name(const char *name,
6667                                enum bpf_attach_type *attach_type)
6668 {
6669         char *type_names;
6670         int i;
6671
6672         if (!name)
6673                 return -EINVAL;
6674
6675         for (i = 0; i < ARRAY_SIZE(section_defs); i++) {
6676                 if (strncmp(name, section_defs[i].sec, section_defs[i].len))
6677                         continue;
6678                 if (!section_defs[i].is_attachable)
6679                         return -EINVAL;
6680                 *attach_type = section_defs[i].attach_type;
6681                 return 0;
6682         }
6683         pr_debug("failed to guess attach type based on ELF section name '%s'\n", name);
6684         type_names = libbpf_get_type_names(true);
6685         if (type_names != NULL) {
6686                 pr_debug("attachable section(type) names are:%s\n", type_names);
6687                 free(type_names);
6688         }
6689
6690         return -EINVAL;
6691 }
6692
6693 int bpf_map__fd(const struct bpf_map *map)
6694 {
6695         return map ? map->fd : -EINVAL;
6696 }
6697
6698 const struct bpf_map_def *bpf_map__def(const struct bpf_map *map)
6699 {
6700         return map ? &map->def : ERR_PTR(-EINVAL);
6701 }
6702
6703 const char *bpf_map__name(const struct bpf_map *map)
6704 {
6705         return map ? map->name : NULL;
6706 }
6707
6708 __u32 bpf_map__btf_key_type_id(const struct bpf_map *map)
6709 {
6710         return map ? map->btf_key_type_id : 0;
6711 }
6712
6713 __u32 bpf_map__btf_value_type_id(const struct bpf_map *map)
6714 {
6715         return map ? map->btf_value_type_id : 0;
6716 }
6717
6718 int bpf_map__set_priv(struct bpf_map *map, void *priv,
6719                      bpf_map_clear_priv_t clear_priv)
6720 {
6721         if (!map)
6722                 return -EINVAL;
6723
6724         if (map->priv) {
6725                 if (map->clear_priv)
6726                         map->clear_priv(map, map->priv);
6727         }
6728
6729         map->priv = priv;
6730         map->clear_priv = clear_priv;
6731         return 0;
6732 }
6733
6734 void *bpf_map__priv(const struct bpf_map *map)
6735 {
6736         return map ? map->priv : ERR_PTR(-EINVAL);
6737 }
6738
6739 bool bpf_map__is_offload_neutral(const struct bpf_map *map)
6740 {
6741         return map->def.type == BPF_MAP_TYPE_PERF_EVENT_ARRAY;
6742 }
6743
6744 bool bpf_map__is_internal(const struct bpf_map *map)
6745 {
6746         return map->libbpf_type != LIBBPF_MAP_UNSPEC;
6747 }
6748
6749 void bpf_map__set_ifindex(struct bpf_map *map, __u32 ifindex)
6750 {
6751         map->map_ifindex = ifindex;
6752 }
6753
6754 int bpf_map__set_inner_map_fd(struct bpf_map *map, int fd)
6755 {
6756         if (!bpf_map_type__is_map_in_map(map->def.type)) {
6757                 pr_warn("error: unsupported map type\n");
6758                 return -EINVAL;
6759         }
6760         if (map->inner_map_fd != -1) {
6761                 pr_warn("error: inner_map_fd already specified\n");
6762                 return -EINVAL;
6763         }
6764         map->inner_map_fd = fd;
6765         return 0;
6766 }
6767
6768 static struct bpf_map *
6769 __bpf_map__iter(const struct bpf_map *m, const struct bpf_object *obj, int i)
6770 {
6771         ssize_t idx;
6772         struct bpf_map *s, *e;
6773
6774         if (!obj || !obj->maps)
6775                 return NULL;
6776
6777         s = obj->maps;
6778         e = obj->maps + obj->nr_maps;
6779
6780         if ((m < s) || (m >= e)) {
6781                 pr_warn("error in %s: map handler doesn't belong to object\n",
6782                          __func__);
6783                 return NULL;
6784         }
6785
6786         idx = (m - obj->maps) + i;
6787         if (idx >= obj->nr_maps || idx < 0)
6788                 return NULL;
6789         return &obj->maps[idx];
6790 }
6791
6792 struct bpf_map *
6793 bpf_map__next(const struct bpf_map *prev, const struct bpf_object *obj)
6794 {
6795         if (prev == NULL)
6796                 return obj->maps;
6797
6798         return __bpf_map__iter(prev, obj, 1);
6799 }
6800
6801 struct bpf_map *
6802 bpf_map__prev(const struct bpf_map *next, const struct bpf_object *obj)
6803 {
6804         if (next == NULL) {
6805                 if (!obj->nr_maps)
6806                         return NULL;
6807                 return obj->maps + obj->nr_maps - 1;
6808         }
6809
6810         return __bpf_map__iter(next, obj, -1);
6811 }
6812
6813 struct bpf_map *
6814 bpf_object__find_map_by_name(const struct bpf_object *obj, const char *name)
6815 {
6816         struct bpf_map *pos;
6817
6818         bpf_object__for_each_map(pos, obj) {
6819                 if (pos->name && !strcmp(pos->name, name))
6820                         return pos;
6821         }
6822         return NULL;
6823 }
6824
6825 int
6826 bpf_object__find_map_fd_by_name(const struct bpf_object *obj, const char *name)
6827 {
6828         return bpf_map__fd(bpf_object__find_map_by_name(obj, name));
6829 }
6830
6831 struct bpf_map *
6832 bpf_object__find_map_by_offset(struct bpf_object *obj, size_t offset)
6833 {
6834         return ERR_PTR(-ENOTSUP);
6835 }
6836
6837 long libbpf_get_error(const void *ptr)
6838 {
6839         return PTR_ERR_OR_ZERO(ptr);
6840 }
6841
6842 int bpf_prog_load(const char *file, enum bpf_prog_type type,
6843                   struct bpf_object **pobj, int *prog_fd)
6844 {
6845         struct bpf_prog_load_attr attr;
6846
6847         memset(&attr, 0, sizeof(struct bpf_prog_load_attr));
6848         attr.file = file;
6849         attr.prog_type = type;
6850         attr.expected_attach_type = 0;
6851
6852         return bpf_prog_load_xattr(&attr, pobj, prog_fd);
6853 }
6854
6855 int bpf_prog_load_xattr(const struct bpf_prog_load_attr *attr,
6856                         struct bpf_object **pobj, int *prog_fd)
6857 {
6858         struct bpf_object_open_attr open_attr = {};
6859         struct bpf_program *prog, *first_prog = NULL;
6860         struct bpf_object *obj;
6861         struct bpf_map *map;
6862         int err;
6863
6864         if (!attr)
6865                 return -EINVAL;
6866         if (!attr->file)
6867                 return -EINVAL;
6868
6869         open_attr.file = attr->file;
6870         open_attr.prog_type = attr->prog_type;
6871
6872         obj = bpf_object__open_xattr(&open_attr);
6873         if (IS_ERR_OR_NULL(obj))
6874                 return -ENOENT;
6875
6876         bpf_object__for_each_program(prog, obj) {
6877                 enum bpf_attach_type attach_type = attr->expected_attach_type;
6878                 /*
6879                  * to preserve backwards compatibility, bpf_prog_load treats
6880                  * attr->prog_type, if specified, as an override to whatever
6881                  * bpf_object__open guessed
6882                  */
6883                 if (attr->prog_type != BPF_PROG_TYPE_UNSPEC) {
6884                         bpf_program__set_type(prog, attr->prog_type);
6885                         bpf_program__set_expected_attach_type(prog,
6886                                                               attach_type);
6887                 }
6888                 if (bpf_program__get_type(prog) == BPF_PROG_TYPE_UNSPEC) {
6889                         /*
6890                          * we haven't guessed from section name and user
6891                          * didn't provide a fallback type, too bad...
6892                          */
6893                         bpf_object__close(obj);
6894                         return -EINVAL;
6895                 }
6896
6897                 prog->prog_ifindex = attr->ifindex;
6898                 prog->log_level = attr->log_level;
6899                 prog->prog_flags = attr->prog_flags;
6900                 if (!first_prog)
6901                         first_prog = prog;
6902         }
6903
6904         bpf_object__for_each_map(map, obj) {
6905                 if (!bpf_map__is_offload_neutral(map))
6906                         map->map_ifindex = attr->ifindex;
6907         }
6908
6909         if (!first_prog) {
6910                 pr_warn("object file doesn't contain bpf program\n");
6911                 bpf_object__close(obj);
6912                 return -ENOENT;
6913         }
6914
6915         err = bpf_object__load(obj);
6916         if (err) {
6917                 bpf_object__close(obj);
6918                 return -EINVAL;
6919         }
6920
6921         *pobj = obj;
6922         *prog_fd = bpf_program__fd(first_prog);
6923         return 0;
6924 }
6925
6926 struct bpf_link {
6927         int (*detach)(struct bpf_link *link);
6928         int (*destroy)(struct bpf_link *link);
6929         bool disconnected;
6930 };
6931
6932 /* Release "ownership" of underlying BPF resource (typically, BPF program
6933  * attached to some BPF hook, e.g., tracepoint, kprobe, etc). Disconnected
6934  * link, when destructed through bpf_link__destroy() call won't attempt to
6935  * detach/unregisted that BPF resource. This is useful in situations where,
6936  * say, attached BPF program has to outlive userspace program that attached it
6937  * in the system. Depending on type of BPF program, though, there might be
6938  * additional steps (like pinning BPF program in BPF FS) necessary to ensure
6939  * exit of userspace program doesn't trigger automatic detachment and clean up
6940  * inside the kernel.
6941  */
6942 void bpf_link__disconnect(struct bpf_link *link)
6943 {
6944         link->disconnected = true;
6945 }
6946
6947 int bpf_link__destroy(struct bpf_link *link)
6948 {
6949         int err = 0;
6950
6951         if (!link)
6952                 return 0;
6953
6954         if (!link->disconnected && link->detach)
6955                 err = link->detach(link);
6956         if (link->destroy)
6957                 link->destroy(link);
6958         free(link);
6959
6960         return err;
6961 }
6962
6963 struct bpf_link_fd {
6964         struct bpf_link link; /* has to be at the top of struct */
6965         int fd; /* hook FD */
6966 };
6967
6968 static int bpf_link__detach_perf_event(struct bpf_link *link)
6969 {
6970         struct bpf_link_fd *l = (void *)link;
6971         int err;
6972
6973         err = ioctl(l->fd, PERF_EVENT_IOC_DISABLE, 0);
6974         if (err)
6975                 err = -errno;
6976
6977         close(l->fd);
6978         return err;
6979 }
6980
6981 struct bpf_link *bpf_program__attach_perf_event(struct bpf_program *prog,
6982                                                 int pfd)
6983 {
6984         char errmsg[STRERR_BUFSIZE];
6985         struct bpf_link_fd *link;
6986         int prog_fd, err;
6987
6988         if (pfd < 0) {
6989                 pr_warn("program '%s': invalid perf event FD %d\n",
6990                         bpf_program__title(prog, false), pfd);
6991                 return ERR_PTR(-EINVAL);
6992         }
6993         prog_fd = bpf_program__fd(prog);
6994         if (prog_fd < 0) {
6995                 pr_warn("program '%s': can't attach BPF program w/o FD (did you load it?)\n",
6996                         bpf_program__title(prog, false));
6997                 return ERR_PTR(-EINVAL);
6998         }
6999
7000         link = calloc(1, sizeof(*link));
7001         if (!link)
7002                 return ERR_PTR(-ENOMEM);
7003         link->link.detach = &bpf_link__detach_perf_event;
7004         link->fd = pfd;
7005
7006         if (ioctl(pfd, PERF_EVENT_IOC_SET_BPF, prog_fd) < 0) {
7007                 err = -errno;
7008                 free(link);
7009                 pr_warn("program '%s': failed to attach to pfd %d: %s\n",
7010                         bpf_program__title(prog, false), pfd,
7011                            libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
7012                 return ERR_PTR(err);
7013         }
7014         if (ioctl(pfd, PERF_EVENT_IOC_ENABLE, 0) < 0) {
7015                 err = -errno;
7016                 free(link);
7017                 pr_warn("program '%s': failed to enable pfd %d: %s\n",
7018                         bpf_program__title(prog, false), pfd,
7019                            libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
7020                 return ERR_PTR(err);
7021         }
7022         return (struct bpf_link *)link;
7023 }
7024
7025 /*
7026  * this function is expected to parse integer in the range of [0, 2^31-1] from
7027  * given file using scanf format string fmt. If actual parsed value is
7028  * negative, the result might be indistinguishable from error
7029  */
7030 static int parse_uint_from_file(const char *file, const char *fmt)
7031 {
7032         char buf[STRERR_BUFSIZE];
7033         int err, ret;
7034         FILE *f;
7035
7036         f = fopen(file, "r");
7037         if (!f) {
7038                 err = -errno;
7039                 pr_debug("failed to open '%s': %s\n", file,
7040                          libbpf_strerror_r(err, buf, sizeof(buf)));
7041                 return err;
7042         }
7043         err = fscanf(f, fmt, &ret);
7044         if (err != 1) {
7045                 err = err == EOF ? -EIO : -errno;
7046                 pr_debug("failed to parse '%s': %s\n", file,
7047                         libbpf_strerror_r(err, buf, sizeof(buf)));
7048                 fclose(f);
7049                 return err;
7050         }
7051         fclose(f);
7052         return ret;
7053 }
7054
7055 static int determine_kprobe_perf_type(void)
7056 {
7057         const char *file = "/sys/bus/event_source/devices/kprobe/type";
7058
7059         return parse_uint_from_file(file, "%d\n");
7060 }
7061
7062 static int determine_uprobe_perf_type(void)
7063 {
7064         const char *file = "/sys/bus/event_source/devices/uprobe/type";
7065
7066         return parse_uint_from_file(file, "%d\n");
7067 }
7068
7069 static int determine_kprobe_retprobe_bit(void)
7070 {
7071         const char *file = "/sys/bus/event_source/devices/kprobe/format/retprobe";
7072
7073         return parse_uint_from_file(file, "config:%d\n");
7074 }
7075
7076 static int determine_uprobe_retprobe_bit(void)
7077 {
7078         const char *file = "/sys/bus/event_source/devices/uprobe/format/retprobe";
7079
7080         return parse_uint_from_file(file, "config:%d\n");
7081 }
7082
7083 static int perf_event_open_probe(bool uprobe, bool retprobe, const char *name,
7084                                  uint64_t offset, int pid)
7085 {
7086         struct perf_event_attr attr = {};
7087         char errmsg[STRERR_BUFSIZE];
7088         int type, pfd, err;
7089
7090         type = uprobe ? determine_uprobe_perf_type()
7091                       : determine_kprobe_perf_type();
7092         if (type < 0) {
7093                 pr_warn("failed to determine %s perf type: %s\n",
7094                         uprobe ? "uprobe" : "kprobe",
7095                         libbpf_strerror_r(type, errmsg, sizeof(errmsg)));
7096                 return type;
7097         }
7098         if (retprobe) {
7099                 int bit = uprobe ? determine_uprobe_retprobe_bit()
7100                                  : determine_kprobe_retprobe_bit();
7101
7102                 if (bit < 0) {
7103                         pr_warn("failed to determine %s retprobe bit: %s\n",
7104                                 uprobe ? "uprobe" : "kprobe",
7105                                 libbpf_strerror_r(bit, errmsg, sizeof(errmsg)));
7106                         return bit;
7107                 }
7108                 attr.config |= 1 << bit;
7109         }
7110         attr.size = sizeof(attr);
7111         attr.type = type;
7112         attr.config1 = ptr_to_u64(name); /* kprobe_func or uprobe_path */
7113         attr.config2 = offset;           /* kprobe_addr or probe_offset */
7114
7115         /* pid filter is meaningful only for uprobes */
7116         pfd = syscall(__NR_perf_event_open, &attr,
7117                       pid < 0 ? -1 : pid /* pid */,
7118                       pid == -1 ? 0 : -1 /* cpu */,
7119                       -1 /* group_fd */, PERF_FLAG_FD_CLOEXEC);
7120         if (pfd < 0) {
7121                 err = -errno;
7122                 pr_warn("%s perf_event_open() failed: %s\n",
7123                         uprobe ? "uprobe" : "kprobe",
7124                         libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
7125                 return err;
7126         }
7127         return pfd;
7128 }
7129
7130 struct bpf_link *bpf_program__attach_kprobe(struct bpf_program *prog,
7131                                             bool retprobe,
7132                                             const char *func_name)
7133 {
7134         char errmsg[STRERR_BUFSIZE];
7135         struct bpf_link *link;
7136         int pfd, err;
7137
7138         pfd = perf_event_open_probe(false /* uprobe */, retprobe, func_name,
7139                                     0 /* offset */, -1 /* pid */);
7140         if (pfd < 0) {
7141                 pr_warn("program '%s': failed to create %s '%s' perf event: %s\n",
7142                         bpf_program__title(prog, false),
7143                         retprobe ? "kretprobe" : "kprobe", func_name,
7144                         libbpf_strerror_r(pfd, errmsg, sizeof(errmsg)));
7145                 return ERR_PTR(pfd);
7146         }
7147         link = bpf_program__attach_perf_event(prog, pfd);
7148         if (IS_ERR(link)) {
7149                 close(pfd);
7150                 err = PTR_ERR(link);
7151                 pr_warn("program '%s': failed to attach to %s '%s': %s\n",
7152                         bpf_program__title(prog, false),
7153                         retprobe ? "kretprobe" : "kprobe", func_name,
7154                         libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
7155                 return link;
7156         }
7157         return link;
7158 }
7159
7160 static struct bpf_link *attach_kprobe(const struct bpf_sec_def *sec,
7161                                       struct bpf_program *prog)
7162 {
7163         const char *func_name;
7164         bool retprobe;
7165
7166         func_name = bpf_program__title(prog, false) + sec->len;
7167         retprobe = strcmp(sec->sec, "kretprobe/") == 0;
7168
7169         return bpf_program__attach_kprobe(prog, retprobe, func_name);
7170 }
7171
7172 struct bpf_link *bpf_program__attach_uprobe(struct bpf_program *prog,
7173                                             bool retprobe, pid_t pid,
7174                                             const char *binary_path,
7175                                             size_t func_offset)
7176 {
7177         char errmsg[STRERR_BUFSIZE];
7178         struct bpf_link *link;
7179         int pfd, err;
7180
7181         pfd = perf_event_open_probe(true /* uprobe */, retprobe,
7182                                     binary_path, func_offset, pid);
7183         if (pfd < 0) {
7184                 pr_warn("program '%s': failed to create %s '%s:0x%zx' perf event: %s\n",
7185                         bpf_program__title(prog, false),
7186                         retprobe ? "uretprobe" : "uprobe",
7187                         binary_path, func_offset,
7188                         libbpf_strerror_r(pfd, errmsg, sizeof(errmsg)));
7189                 return ERR_PTR(pfd);
7190         }
7191         link = bpf_program__attach_perf_event(prog, pfd);
7192         if (IS_ERR(link)) {
7193                 close(pfd);
7194                 err = PTR_ERR(link);
7195                 pr_warn("program '%s': failed to attach to %s '%s:0x%zx': %s\n",
7196                         bpf_program__title(prog, false),
7197                         retprobe ? "uretprobe" : "uprobe",
7198                         binary_path, func_offset,
7199                         libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
7200                 return link;
7201         }
7202         return link;
7203 }
7204
7205 static int determine_tracepoint_id(const char *tp_category,
7206                                    const char *tp_name)
7207 {
7208         char file[PATH_MAX];
7209         int ret;
7210
7211         ret = snprintf(file, sizeof(file),
7212                        "/sys/kernel/debug/tracing/events/%s/%s/id",
7213                        tp_category, tp_name);
7214         if (ret < 0)
7215                 return -errno;
7216         if (ret >= sizeof(file)) {
7217                 pr_debug("tracepoint %s/%s path is too long\n",
7218                          tp_category, tp_name);
7219                 return -E2BIG;
7220         }
7221         return parse_uint_from_file(file, "%d\n");
7222 }
7223
7224 static int perf_event_open_tracepoint(const char *tp_category,
7225                                       const char *tp_name)
7226 {
7227         struct perf_event_attr attr = {};
7228         char errmsg[STRERR_BUFSIZE];
7229         int tp_id, pfd, err;
7230
7231         tp_id = determine_tracepoint_id(tp_category, tp_name);
7232         if (tp_id < 0) {
7233                 pr_warn("failed to determine tracepoint '%s/%s' perf event ID: %s\n",
7234                         tp_category, tp_name,
7235                         libbpf_strerror_r(tp_id, errmsg, sizeof(errmsg)));
7236                 return tp_id;
7237         }
7238
7239         attr.type = PERF_TYPE_TRACEPOINT;
7240         attr.size = sizeof(attr);
7241         attr.config = tp_id;
7242
7243         pfd = syscall(__NR_perf_event_open, &attr, -1 /* pid */, 0 /* cpu */,
7244                       -1 /* group_fd */, PERF_FLAG_FD_CLOEXEC);
7245         if (pfd < 0) {
7246                 err = -errno;
7247                 pr_warn("tracepoint '%s/%s' perf_event_open() failed: %s\n",
7248                         tp_category, tp_name,
7249                         libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
7250                 return err;
7251         }
7252         return pfd;
7253 }
7254
7255 struct bpf_link *bpf_program__attach_tracepoint(struct bpf_program *prog,
7256                                                 const char *tp_category,
7257                                                 const char *tp_name)
7258 {
7259         char errmsg[STRERR_BUFSIZE];
7260         struct bpf_link *link;
7261         int pfd, err;
7262
7263         pfd = perf_event_open_tracepoint(tp_category, tp_name);
7264         if (pfd < 0) {
7265                 pr_warn("program '%s': failed to create tracepoint '%s/%s' perf event: %s\n",
7266                         bpf_program__title(prog, false),
7267                         tp_category, tp_name,
7268                         libbpf_strerror_r(pfd, errmsg, sizeof(errmsg)));
7269                 return ERR_PTR(pfd);
7270         }
7271         link = bpf_program__attach_perf_event(prog, pfd);
7272         if (IS_ERR(link)) {
7273                 close(pfd);
7274                 err = PTR_ERR(link);
7275                 pr_warn("program '%s': failed to attach to tracepoint '%s/%s': %s\n",
7276                         bpf_program__title(prog, false),
7277                         tp_category, tp_name,
7278                         libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
7279                 return link;
7280         }
7281         return link;
7282 }
7283
7284 static struct bpf_link *attach_tp(const struct bpf_sec_def *sec,
7285                                   struct bpf_program *prog)
7286 {
7287         char *sec_name, *tp_cat, *tp_name;
7288         struct bpf_link *link;
7289
7290         sec_name = strdup(bpf_program__title(prog, false));
7291         if (!sec_name)
7292                 return ERR_PTR(-ENOMEM);
7293
7294         /* extract "tp/<category>/<name>" */
7295         tp_cat = sec_name + sec->len;
7296         tp_name = strchr(tp_cat, '/');
7297         if (!tp_name) {
7298                 link = ERR_PTR(-EINVAL);
7299                 goto out;
7300         }
7301         *tp_name = '\0';
7302         tp_name++;
7303
7304         link = bpf_program__attach_tracepoint(prog, tp_cat, tp_name);
7305 out:
7306         free(sec_name);
7307         return link;
7308 }
7309
7310 static int bpf_link__detach_fd(struct bpf_link *link)
7311 {
7312         struct bpf_link_fd *l = (void *)link;
7313
7314         return close(l->fd);
7315 }
7316
7317 struct bpf_link *bpf_program__attach_raw_tracepoint(struct bpf_program *prog,
7318                                                     const char *tp_name)
7319 {
7320         char errmsg[STRERR_BUFSIZE];
7321         struct bpf_link_fd *link;
7322         int prog_fd, pfd;
7323
7324         prog_fd = bpf_program__fd(prog);
7325         if (prog_fd < 0) {
7326                 pr_warn("program '%s': can't attach before loaded\n",
7327                         bpf_program__title(prog, false));
7328                 return ERR_PTR(-EINVAL);
7329         }
7330
7331         link = calloc(1, sizeof(*link));
7332         if (!link)
7333                 return ERR_PTR(-ENOMEM);
7334         link->link.detach = &bpf_link__detach_fd;
7335
7336         pfd = bpf_raw_tracepoint_open(tp_name, prog_fd);
7337         if (pfd < 0) {
7338                 pfd = -errno;
7339                 free(link);
7340                 pr_warn("program '%s': failed to attach to raw tracepoint '%s': %s\n",
7341                         bpf_program__title(prog, false), tp_name,
7342                         libbpf_strerror_r(pfd, errmsg, sizeof(errmsg)));
7343                 return ERR_PTR(pfd);
7344         }
7345         link->fd = pfd;
7346         return (struct bpf_link *)link;
7347 }
7348
7349 static struct bpf_link *attach_raw_tp(const struct bpf_sec_def *sec,
7350                                       struct bpf_program *prog)
7351 {
7352         const char *tp_name = bpf_program__title(prog, false) + sec->len;
7353
7354         return bpf_program__attach_raw_tracepoint(prog, tp_name);
7355 }
7356
7357 struct bpf_link *bpf_program__attach_trace(struct bpf_program *prog)
7358 {
7359         char errmsg[STRERR_BUFSIZE];
7360         struct bpf_link_fd *link;
7361         int prog_fd, pfd;
7362
7363         prog_fd = bpf_program__fd(prog);
7364         if (prog_fd < 0) {
7365                 pr_warn("program '%s': can't attach before loaded\n",
7366                         bpf_program__title(prog, false));
7367                 return ERR_PTR(-EINVAL);
7368         }
7369
7370         link = calloc(1, sizeof(*link));
7371         if (!link)
7372                 return ERR_PTR(-ENOMEM);
7373         link->link.detach = &bpf_link__detach_fd;
7374
7375         pfd = bpf_raw_tracepoint_open(NULL, prog_fd);
7376         if (pfd < 0) {
7377                 pfd = -errno;
7378                 free(link);
7379                 pr_warn("program '%s': failed to attach to trace: %s\n",
7380                         bpf_program__title(prog, false),
7381                         libbpf_strerror_r(pfd, errmsg, sizeof(errmsg)));
7382                 return ERR_PTR(pfd);
7383         }
7384         link->fd = pfd;
7385         return (struct bpf_link *)link;
7386 }
7387
7388 static struct bpf_link *attach_trace(const struct bpf_sec_def *sec,
7389                                      struct bpf_program *prog)
7390 {
7391         return bpf_program__attach_trace(prog);
7392 }
7393
7394 struct bpf_link *bpf_program__attach(struct bpf_program *prog)
7395 {
7396         const struct bpf_sec_def *sec_def;
7397
7398         sec_def = find_sec_def(bpf_program__title(prog, false));
7399         if (!sec_def || !sec_def->attach_fn)
7400                 return ERR_PTR(-ESRCH);
7401
7402         return sec_def->attach_fn(sec_def, prog);
7403 }
7404
7405 static int bpf_link__detach_struct_ops(struct bpf_link *link)
7406 {
7407         struct bpf_link_fd *l = (void *)link;
7408         __u32 zero = 0;
7409
7410         if (bpf_map_delete_elem(l->fd, &zero))
7411                 return -errno;
7412
7413         return 0;
7414 }
7415
7416 struct bpf_link *bpf_map__attach_struct_ops(struct bpf_map *map)
7417 {
7418         struct bpf_struct_ops *st_ops;
7419         struct bpf_link_fd *link;
7420         __u32 i, zero = 0;
7421         int err;
7422
7423         if (!bpf_map__is_struct_ops(map) || map->fd == -1)
7424                 return ERR_PTR(-EINVAL);
7425
7426         link = calloc(1, sizeof(*link));
7427         if (!link)
7428                 return ERR_PTR(-EINVAL);
7429
7430         st_ops = map->st_ops;
7431         for (i = 0; i < btf_vlen(st_ops->type); i++) {
7432                 struct bpf_program *prog = st_ops->progs[i];
7433                 void *kern_data;
7434                 int prog_fd;
7435
7436                 if (!prog)
7437                         continue;
7438
7439                 prog_fd = bpf_program__fd(prog);
7440                 kern_data = st_ops->kern_vdata + st_ops->kern_func_off[i];
7441                 *(unsigned long *)kern_data = prog_fd;
7442         }
7443
7444         err = bpf_map_update_elem(map->fd, &zero, st_ops->kern_vdata, 0);
7445         if (err) {
7446                 err = -errno;
7447                 free(link);
7448                 return ERR_PTR(err);
7449         }
7450
7451         link->link.detach = bpf_link__detach_struct_ops;
7452         link->fd = map->fd;
7453
7454         return (struct bpf_link *)link;
7455 }
7456
7457 enum bpf_perf_event_ret
7458 bpf_perf_event_read_simple(void *mmap_mem, size_t mmap_size, size_t page_size,
7459                            void **copy_mem, size_t *copy_size,
7460                            bpf_perf_event_print_t fn, void *private_data)
7461 {
7462         struct perf_event_mmap_page *header = mmap_mem;
7463         __u64 data_head = ring_buffer_read_head(header);
7464         __u64 data_tail = header->data_tail;
7465         void *base = ((__u8 *)header) + page_size;
7466         int ret = LIBBPF_PERF_EVENT_CONT;
7467         struct perf_event_header *ehdr;
7468         size_t ehdr_size;
7469
7470         while (data_head != data_tail) {
7471                 ehdr = base + (data_tail & (mmap_size - 1));
7472                 ehdr_size = ehdr->size;
7473
7474                 if (((void *)ehdr) + ehdr_size > base + mmap_size) {
7475                         void *copy_start = ehdr;
7476                         size_t len_first = base + mmap_size - copy_start;
7477                         size_t len_secnd = ehdr_size - len_first;
7478
7479                         if (*copy_size < ehdr_size) {
7480                                 free(*copy_mem);
7481                                 *copy_mem = malloc(ehdr_size);
7482                                 if (!*copy_mem) {
7483                                         *copy_size = 0;
7484                                         ret = LIBBPF_PERF_EVENT_ERROR;
7485                                         break;
7486                                 }
7487                                 *copy_size = ehdr_size;
7488                         }
7489
7490                         memcpy(*copy_mem, copy_start, len_first);
7491                         memcpy(*copy_mem + len_first, base, len_secnd);
7492                         ehdr = *copy_mem;
7493                 }
7494
7495                 ret = fn(ehdr, private_data);
7496                 data_tail += ehdr_size;
7497                 if (ret != LIBBPF_PERF_EVENT_CONT)
7498                         break;
7499         }
7500
7501         ring_buffer_write_tail(header, data_tail);
7502         return ret;
7503 }
7504
7505 struct perf_buffer;
7506
7507 struct perf_buffer_params {
7508         struct perf_event_attr *attr;
7509         /* if event_cb is specified, it takes precendence */
7510         perf_buffer_event_fn event_cb;
7511         /* sample_cb and lost_cb are higher-level common-case callbacks */
7512         perf_buffer_sample_fn sample_cb;
7513         perf_buffer_lost_fn lost_cb;
7514         void *ctx;
7515         int cpu_cnt;
7516         int *cpus;
7517         int *map_keys;
7518 };
7519
7520 struct perf_cpu_buf {
7521         struct perf_buffer *pb;
7522         void *base; /* mmap()'ed memory */
7523         void *buf; /* for reconstructing segmented data */
7524         size_t buf_size;
7525         int fd;
7526         int cpu;
7527         int map_key;
7528 };
7529
7530 struct perf_buffer {
7531         perf_buffer_event_fn event_cb;
7532         perf_buffer_sample_fn sample_cb;
7533         perf_buffer_lost_fn lost_cb;
7534         void *ctx; /* passed into callbacks */
7535
7536         size_t page_size;
7537         size_t mmap_size;
7538         struct perf_cpu_buf **cpu_bufs;
7539         struct epoll_event *events;
7540         int cpu_cnt; /* number of allocated CPU buffers */
7541         int epoll_fd; /* perf event FD */
7542         int map_fd; /* BPF_MAP_TYPE_PERF_EVENT_ARRAY BPF map FD */
7543 };
7544
7545 static void perf_buffer__free_cpu_buf(struct perf_buffer *pb,
7546                                       struct perf_cpu_buf *cpu_buf)
7547 {
7548         if (!cpu_buf)
7549                 return;
7550         if (cpu_buf->base &&
7551             munmap(cpu_buf->base, pb->mmap_size + pb->page_size))
7552                 pr_warn("failed to munmap cpu_buf #%d\n", cpu_buf->cpu);
7553         if (cpu_buf->fd >= 0) {
7554                 ioctl(cpu_buf->fd, PERF_EVENT_IOC_DISABLE, 0);
7555                 close(cpu_buf->fd);
7556         }
7557         free(cpu_buf->buf);
7558         free(cpu_buf);
7559 }
7560
7561 void perf_buffer__free(struct perf_buffer *pb)
7562 {
7563         int i;
7564
7565         if (!pb)
7566                 return;
7567         if (pb->cpu_bufs) {
7568                 for (i = 0; i < pb->cpu_cnt && pb->cpu_bufs[i]; i++) {
7569                         struct perf_cpu_buf *cpu_buf = pb->cpu_bufs[i];
7570
7571                         bpf_map_delete_elem(pb->map_fd, &cpu_buf->map_key);
7572                         perf_buffer__free_cpu_buf(pb, cpu_buf);
7573                 }
7574                 free(pb->cpu_bufs);
7575         }
7576         if (pb->epoll_fd >= 0)
7577                 close(pb->epoll_fd);
7578         free(pb->events);
7579         free(pb);
7580 }
7581
7582 static struct perf_cpu_buf *
7583 perf_buffer__open_cpu_buf(struct perf_buffer *pb, struct perf_event_attr *attr,
7584                           int cpu, int map_key)
7585 {
7586         struct perf_cpu_buf *cpu_buf;
7587         char msg[STRERR_BUFSIZE];
7588         int err;
7589
7590         cpu_buf = calloc(1, sizeof(*cpu_buf));
7591         if (!cpu_buf)
7592                 return ERR_PTR(-ENOMEM);
7593
7594         cpu_buf->pb = pb;
7595         cpu_buf->cpu = cpu;
7596         cpu_buf->map_key = map_key;
7597
7598         cpu_buf->fd = syscall(__NR_perf_event_open, attr, -1 /* pid */, cpu,
7599                               -1, PERF_FLAG_FD_CLOEXEC);
7600         if (cpu_buf->fd < 0) {
7601                 err = -errno;
7602                 pr_warn("failed to open perf buffer event on cpu #%d: %s\n",
7603                         cpu, libbpf_strerror_r(err, msg, sizeof(msg)));
7604                 goto error;
7605         }
7606
7607         cpu_buf->base = mmap(NULL, pb->mmap_size + pb->page_size,
7608                              PROT_READ | PROT_WRITE, MAP_SHARED,
7609                              cpu_buf->fd, 0);
7610         if (cpu_buf->base == MAP_FAILED) {
7611                 cpu_buf->base = NULL;
7612                 err = -errno;
7613                 pr_warn("failed to mmap perf buffer on cpu #%d: %s\n",
7614                         cpu, libbpf_strerror_r(err, msg, sizeof(msg)));
7615                 goto error;
7616         }
7617
7618         if (ioctl(cpu_buf->fd, PERF_EVENT_IOC_ENABLE, 0) < 0) {
7619                 err = -errno;
7620                 pr_warn("failed to enable perf buffer event on cpu #%d: %s\n",
7621                         cpu, libbpf_strerror_r(err, msg, sizeof(msg)));
7622                 goto error;
7623         }
7624
7625         return cpu_buf;
7626
7627 error:
7628         perf_buffer__free_cpu_buf(pb, cpu_buf);
7629         return (struct perf_cpu_buf *)ERR_PTR(err);
7630 }
7631
7632 static struct perf_buffer *__perf_buffer__new(int map_fd, size_t page_cnt,
7633                                               struct perf_buffer_params *p);
7634
7635 struct perf_buffer *perf_buffer__new(int map_fd, size_t page_cnt,
7636                                      const struct perf_buffer_opts *opts)
7637 {
7638         struct perf_buffer_params p = {};
7639         struct perf_event_attr attr = { 0, };
7640
7641         attr.config = PERF_COUNT_SW_BPF_OUTPUT,
7642         attr.type = PERF_TYPE_SOFTWARE;
7643         attr.sample_type = PERF_SAMPLE_RAW;
7644         attr.sample_period = 1;
7645         attr.wakeup_events = 1;
7646
7647         p.attr = &attr;
7648         p.sample_cb = opts ? opts->sample_cb : NULL;
7649         p.lost_cb = opts ? opts->lost_cb : NULL;
7650         p.ctx = opts ? opts->ctx : NULL;
7651
7652         return __perf_buffer__new(map_fd, page_cnt, &p);
7653 }
7654
7655 struct perf_buffer *
7656 perf_buffer__new_raw(int map_fd, size_t page_cnt,
7657                      const struct perf_buffer_raw_opts *opts)
7658 {
7659         struct perf_buffer_params p = {};
7660
7661         p.attr = opts->attr;
7662         p.event_cb = opts->event_cb;
7663         p.ctx = opts->ctx;
7664         p.cpu_cnt = opts->cpu_cnt;
7665         p.cpus = opts->cpus;
7666         p.map_keys = opts->map_keys;
7667
7668         return __perf_buffer__new(map_fd, page_cnt, &p);
7669 }
7670
7671 static struct perf_buffer *__perf_buffer__new(int map_fd, size_t page_cnt,
7672                                               struct perf_buffer_params *p)
7673 {
7674         const char *online_cpus_file = "/sys/devices/system/cpu/online";
7675         struct bpf_map_info map = {};
7676         char msg[STRERR_BUFSIZE];
7677         struct perf_buffer *pb;
7678         bool *online = NULL;
7679         __u32 map_info_len;
7680         int err, i, j, n;
7681
7682         if (page_cnt & (page_cnt - 1)) {
7683                 pr_warn("page count should be power of two, but is %zu\n",
7684                         page_cnt);
7685                 return ERR_PTR(-EINVAL);
7686         }
7687
7688         map_info_len = sizeof(map);
7689         err = bpf_obj_get_info_by_fd(map_fd, &map, &map_info_len);
7690         if (err) {
7691                 err = -errno;
7692                 pr_warn("failed to get map info for map FD %d: %s\n",
7693                         map_fd, libbpf_strerror_r(err, msg, sizeof(msg)));
7694                 return ERR_PTR(err);
7695         }
7696
7697         if (map.type != BPF_MAP_TYPE_PERF_EVENT_ARRAY) {
7698                 pr_warn("map '%s' should be BPF_MAP_TYPE_PERF_EVENT_ARRAY\n",
7699                         map.name);
7700                 return ERR_PTR(-EINVAL);
7701         }
7702
7703         pb = calloc(1, sizeof(*pb));
7704         if (!pb)
7705                 return ERR_PTR(-ENOMEM);
7706
7707         pb->event_cb = p->event_cb;
7708         pb->sample_cb = p->sample_cb;
7709         pb->lost_cb = p->lost_cb;
7710         pb->ctx = p->ctx;
7711
7712         pb->page_size = getpagesize();
7713         pb->mmap_size = pb->page_size * page_cnt;
7714         pb->map_fd = map_fd;
7715
7716         pb->epoll_fd = epoll_create1(EPOLL_CLOEXEC);
7717         if (pb->epoll_fd < 0) {
7718                 err = -errno;
7719                 pr_warn("failed to create epoll instance: %s\n",
7720                         libbpf_strerror_r(err, msg, sizeof(msg)));
7721                 goto error;
7722         }
7723
7724         if (p->cpu_cnt > 0) {
7725                 pb->cpu_cnt = p->cpu_cnt;
7726         } else {
7727                 pb->cpu_cnt = libbpf_num_possible_cpus();
7728                 if (pb->cpu_cnt < 0) {
7729                         err = pb->cpu_cnt;
7730                         goto error;
7731                 }
7732                 if (map.max_entries < pb->cpu_cnt)
7733                         pb->cpu_cnt = map.max_entries;
7734         }
7735
7736         pb->events = calloc(pb->cpu_cnt, sizeof(*pb->events));
7737         if (!pb->events) {
7738                 err = -ENOMEM;
7739                 pr_warn("failed to allocate events: out of memory\n");
7740                 goto error;
7741         }
7742         pb->cpu_bufs = calloc(pb->cpu_cnt, sizeof(*pb->cpu_bufs));
7743         if (!pb->cpu_bufs) {
7744                 err = -ENOMEM;
7745                 pr_warn("failed to allocate buffers: out of memory\n");
7746                 goto error;
7747         }
7748
7749         err = parse_cpu_mask_file(online_cpus_file, &online, &n);
7750         if (err) {
7751                 pr_warn("failed to get online CPU mask: %d\n", err);
7752                 goto error;
7753         }
7754
7755         for (i = 0, j = 0; i < pb->cpu_cnt; i++) {
7756                 struct perf_cpu_buf *cpu_buf;
7757                 int cpu, map_key;
7758
7759                 cpu = p->cpu_cnt > 0 ? p->cpus[i] : i;
7760                 map_key = p->cpu_cnt > 0 ? p->map_keys[i] : i;
7761
7762                 /* in case user didn't explicitly requested particular CPUs to
7763                  * be attached to, skip offline/not present CPUs
7764                  */
7765                 if (p->cpu_cnt <= 0 && (cpu >= n || !online[cpu]))
7766                         continue;
7767
7768                 cpu_buf = perf_buffer__open_cpu_buf(pb, p->attr, cpu, map_key);
7769                 if (IS_ERR(cpu_buf)) {
7770                         err = PTR_ERR(cpu_buf);
7771                         goto error;
7772                 }
7773
7774                 pb->cpu_bufs[j] = cpu_buf;
7775
7776                 err = bpf_map_update_elem(pb->map_fd, &map_key,
7777                                           &cpu_buf->fd, 0);
7778                 if (err) {
7779                         err = -errno;
7780                         pr_warn("failed to set cpu #%d, key %d -> perf FD %d: %s\n",
7781                                 cpu, map_key, cpu_buf->fd,
7782                                 libbpf_strerror_r(err, msg, sizeof(msg)));
7783                         goto error;
7784                 }
7785
7786                 pb->events[j].events = EPOLLIN;
7787                 pb->events[j].data.ptr = cpu_buf;
7788                 if (epoll_ctl(pb->epoll_fd, EPOLL_CTL_ADD, cpu_buf->fd,
7789                               &pb->events[j]) < 0) {
7790                         err = -errno;
7791                         pr_warn("failed to epoll_ctl cpu #%d perf FD %d: %s\n",
7792                                 cpu, cpu_buf->fd,
7793                                 libbpf_strerror_r(err, msg, sizeof(msg)));
7794                         goto error;
7795                 }
7796                 j++;
7797         }
7798         pb->cpu_cnt = j;
7799         free(online);
7800
7801         return pb;
7802
7803 error:
7804         free(online);
7805         if (pb)
7806                 perf_buffer__free(pb);
7807         return ERR_PTR(err);
7808 }
7809
7810 struct perf_sample_raw {
7811         struct perf_event_header header;
7812         uint32_t size;
7813         char data[0];
7814 };
7815
7816 struct perf_sample_lost {
7817         struct perf_event_header header;
7818         uint64_t id;
7819         uint64_t lost;
7820         uint64_t sample_id;
7821 };
7822
7823 static enum bpf_perf_event_ret
7824 perf_buffer__process_record(struct perf_event_header *e, void *ctx)
7825 {
7826         struct perf_cpu_buf *cpu_buf = ctx;
7827         struct perf_buffer *pb = cpu_buf->pb;
7828         void *data = e;
7829
7830         /* user wants full control over parsing perf event */
7831         if (pb->event_cb)
7832                 return pb->event_cb(pb->ctx, cpu_buf->cpu, e);
7833
7834         switch (e->type) {
7835         case PERF_RECORD_SAMPLE: {
7836                 struct perf_sample_raw *s = data;
7837
7838                 if (pb->sample_cb)
7839                         pb->sample_cb(pb->ctx, cpu_buf->cpu, s->data, s->size);
7840                 break;
7841         }
7842         case PERF_RECORD_LOST: {
7843                 struct perf_sample_lost *s = data;
7844
7845                 if (pb->lost_cb)
7846                         pb->lost_cb(pb->ctx, cpu_buf->cpu, s->lost);
7847                 break;
7848         }
7849         default:
7850                 pr_warn("unknown perf sample type %d\n", e->type);
7851                 return LIBBPF_PERF_EVENT_ERROR;
7852         }
7853         return LIBBPF_PERF_EVENT_CONT;
7854 }
7855
7856 static int perf_buffer__process_records(struct perf_buffer *pb,
7857                                         struct perf_cpu_buf *cpu_buf)
7858 {
7859         enum bpf_perf_event_ret ret;
7860
7861         ret = bpf_perf_event_read_simple(cpu_buf->base, pb->mmap_size,
7862                                          pb->page_size, &cpu_buf->buf,
7863                                          &cpu_buf->buf_size,
7864                                          perf_buffer__process_record, cpu_buf);
7865         if (ret != LIBBPF_PERF_EVENT_CONT)
7866                 return ret;
7867         return 0;
7868 }
7869
7870 int perf_buffer__poll(struct perf_buffer *pb, int timeout_ms)
7871 {
7872         int i, cnt, err;
7873
7874         cnt = epoll_wait(pb->epoll_fd, pb->events, pb->cpu_cnt, timeout_ms);
7875         for (i = 0; i < cnt; i++) {
7876                 struct perf_cpu_buf *cpu_buf = pb->events[i].data.ptr;
7877
7878                 err = perf_buffer__process_records(pb, cpu_buf);
7879                 if (err) {
7880                         pr_warn("error while processing records: %d\n", err);
7881                         return err;
7882                 }
7883         }
7884         return cnt < 0 ? -errno : cnt;
7885 }
7886
7887 struct bpf_prog_info_array_desc {
7888         int     array_offset;   /* e.g. offset of jited_prog_insns */
7889         int     count_offset;   /* e.g. offset of jited_prog_len */
7890         int     size_offset;    /* > 0: offset of rec size,
7891                                  * < 0: fix size of -size_offset
7892                                  */
7893 };
7894
7895 static struct bpf_prog_info_array_desc bpf_prog_info_array_desc[] = {
7896         [BPF_PROG_INFO_JITED_INSNS] = {
7897                 offsetof(struct bpf_prog_info, jited_prog_insns),
7898                 offsetof(struct bpf_prog_info, jited_prog_len),
7899                 -1,
7900         },
7901         [BPF_PROG_INFO_XLATED_INSNS] = {
7902                 offsetof(struct bpf_prog_info, xlated_prog_insns),
7903                 offsetof(struct bpf_prog_info, xlated_prog_len),
7904                 -1,
7905         },
7906         [BPF_PROG_INFO_MAP_IDS] = {
7907                 offsetof(struct bpf_prog_info, map_ids),
7908                 offsetof(struct bpf_prog_info, nr_map_ids),
7909                 -(int)sizeof(__u32),
7910         },
7911         [BPF_PROG_INFO_JITED_KSYMS] = {
7912                 offsetof(struct bpf_prog_info, jited_ksyms),
7913                 offsetof(struct bpf_prog_info, nr_jited_ksyms),
7914                 -(int)sizeof(__u64),
7915         },
7916         [BPF_PROG_INFO_JITED_FUNC_LENS] = {
7917                 offsetof(struct bpf_prog_info, jited_func_lens),
7918                 offsetof(struct bpf_prog_info, nr_jited_func_lens),
7919                 -(int)sizeof(__u32),
7920         },
7921         [BPF_PROG_INFO_FUNC_INFO] = {
7922                 offsetof(struct bpf_prog_info, func_info),
7923                 offsetof(struct bpf_prog_info, nr_func_info),
7924                 offsetof(struct bpf_prog_info, func_info_rec_size),
7925         },
7926         [BPF_PROG_INFO_LINE_INFO] = {
7927                 offsetof(struct bpf_prog_info, line_info),
7928                 offsetof(struct bpf_prog_info, nr_line_info),
7929                 offsetof(struct bpf_prog_info, line_info_rec_size),
7930         },
7931         [BPF_PROG_INFO_JITED_LINE_INFO] = {
7932                 offsetof(struct bpf_prog_info, jited_line_info),
7933                 offsetof(struct bpf_prog_info, nr_jited_line_info),
7934                 offsetof(struct bpf_prog_info, jited_line_info_rec_size),
7935         },
7936         [BPF_PROG_INFO_PROG_TAGS] = {
7937                 offsetof(struct bpf_prog_info, prog_tags),
7938                 offsetof(struct bpf_prog_info, nr_prog_tags),
7939                 -(int)sizeof(__u8) * BPF_TAG_SIZE,
7940         },
7941
7942 };
7943
7944 static __u32 bpf_prog_info_read_offset_u32(struct bpf_prog_info *info,
7945                                            int offset)
7946 {
7947         __u32 *array = (__u32 *)info;
7948
7949         if (offset >= 0)
7950                 return array[offset / sizeof(__u32)];
7951         return -(int)offset;
7952 }
7953
7954 static __u64 bpf_prog_info_read_offset_u64(struct bpf_prog_info *info,
7955                                            int offset)
7956 {
7957         __u64 *array = (__u64 *)info;
7958
7959         if (offset >= 0)
7960                 return array[offset / sizeof(__u64)];
7961         return -(int)offset;
7962 }
7963
7964 static void bpf_prog_info_set_offset_u32(struct bpf_prog_info *info, int offset,
7965                                          __u32 val)
7966 {
7967         __u32 *array = (__u32 *)info;
7968
7969         if (offset >= 0)
7970                 array[offset / sizeof(__u32)] = val;
7971 }
7972
7973 static void bpf_prog_info_set_offset_u64(struct bpf_prog_info *info, int offset,
7974                                          __u64 val)
7975 {
7976         __u64 *array = (__u64 *)info;
7977
7978         if (offset >= 0)
7979                 array[offset / sizeof(__u64)] = val;
7980 }
7981
7982 struct bpf_prog_info_linear *
7983 bpf_program__get_prog_info_linear(int fd, __u64 arrays)
7984 {
7985         struct bpf_prog_info_linear *info_linear;
7986         struct bpf_prog_info info = {};
7987         __u32 info_len = sizeof(info);
7988         __u32 data_len = 0;
7989         int i, err;
7990         void *ptr;
7991
7992         if (arrays >> BPF_PROG_INFO_LAST_ARRAY)
7993                 return ERR_PTR(-EINVAL);
7994
7995         /* step 1: get array dimensions */
7996         err = bpf_obj_get_info_by_fd(fd, &info, &info_len);
7997         if (err) {
7998                 pr_debug("can't get prog info: %s", strerror(errno));
7999                 return ERR_PTR(-EFAULT);
8000         }
8001
8002         /* step 2: calculate total size of all arrays */
8003         for (i = BPF_PROG_INFO_FIRST_ARRAY; i < BPF_PROG_INFO_LAST_ARRAY; ++i) {
8004                 bool include_array = (arrays & (1UL << i)) > 0;
8005                 struct bpf_prog_info_array_desc *desc;
8006                 __u32 count, size;
8007
8008                 desc = bpf_prog_info_array_desc + i;
8009
8010                 /* kernel is too old to support this field */
8011                 if (info_len < desc->array_offset + sizeof(__u32) ||
8012                     info_len < desc->count_offset + sizeof(__u32) ||
8013                     (desc->size_offset > 0 && info_len < desc->size_offset))
8014                         include_array = false;
8015
8016                 if (!include_array) {
8017                         arrays &= ~(1UL << i);  /* clear the bit */
8018                         continue;
8019                 }
8020
8021                 count = bpf_prog_info_read_offset_u32(&info, desc->count_offset);
8022                 size  = bpf_prog_info_read_offset_u32(&info, desc->size_offset);
8023
8024                 data_len += count * size;
8025         }
8026
8027         /* step 3: allocate continuous memory */
8028         data_len = roundup(data_len, sizeof(__u64));
8029         info_linear = malloc(sizeof(struct bpf_prog_info_linear) + data_len);
8030         if (!info_linear)
8031                 return ERR_PTR(-ENOMEM);
8032
8033         /* step 4: fill data to info_linear->info */
8034         info_linear->arrays = arrays;
8035         memset(&info_linear->info, 0, sizeof(info));
8036         ptr = info_linear->data;
8037
8038         for (i = BPF_PROG_INFO_FIRST_ARRAY; i < BPF_PROG_INFO_LAST_ARRAY; ++i) {
8039                 struct bpf_prog_info_array_desc *desc;
8040                 __u32 count, size;
8041
8042                 if ((arrays & (1UL << i)) == 0)
8043                         continue;
8044
8045                 desc  = bpf_prog_info_array_desc + i;
8046                 count = bpf_prog_info_read_offset_u32(&info, desc->count_offset);
8047                 size  = bpf_prog_info_read_offset_u32(&info, desc->size_offset);
8048                 bpf_prog_info_set_offset_u32(&info_linear->info,
8049                                              desc->count_offset, count);
8050                 bpf_prog_info_set_offset_u32(&info_linear->info,
8051                                              desc->size_offset, size);
8052                 bpf_prog_info_set_offset_u64(&info_linear->info,
8053                                              desc->array_offset,
8054                                              ptr_to_u64(ptr));
8055                 ptr += count * size;
8056         }
8057
8058         /* step 5: call syscall again to get required arrays */
8059         err = bpf_obj_get_info_by_fd(fd, &info_linear->info, &info_len);
8060         if (err) {
8061                 pr_debug("can't get prog info: %s", strerror(errno));
8062                 free(info_linear);
8063                 return ERR_PTR(-EFAULT);
8064         }
8065
8066         /* step 6: verify the data */
8067         for (i = BPF_PROG_INFO_FIRST_ARRAY; i < BPF_PROG_INFO_LAST_ARRAY; ++i) {
8068                 struct bpf_prog_info_array_desc *desc;
8069                 __u32 v1, v2;
8070
8071                 if ((arrays & (1UL << i)) == 0)
8072                         continue;
8073
8074                 desc = bpf_prog_info_array_desc + i;
8075                 v1 = bpf_prog_info_read_offset_u32(&info, desc->count_offset);
8076                 v2 = bpf_prog_info_read_offset_u32(&info_linear->info,
8077                                                    desc->count_offset);
8078                 if (v1 != v2)
8079                         pr_warn("%s: mismatch in element count\n", __func__);
8080
8081                 v1 = bpf_prog_info_read_offset_u32(&info, desc->size_offset);
8082                 v2 = bpf_prog_info_read_offset_u32(&info_linear->info,
8083                                                    desc->size_offset);
8084                 if (v1 != v2)
8085                         pr_warn("%s: mismatch in rec size\n", __func__);
8086         }
8087
8088         /* step 7: update info_len and data_len */
8089         info_linear->info_len = sizeof(struct bpf_prog_info);
8090         info_linear->data_len = data_len;
8091
8092         return info_linear;
8093 }
8094
8095 void bpf_program__bpil_addr_to_offs(struct bpf_prog_info_linear *info_linear)
8096 {
8097         int i;
8098
8099         for (i = BPF_PROG_INFO_FIRST_ARRAY; i < BPF_PROG_INFO_LAST_ARRAY; ++i) {
8100                 struct bpf_prog_info_array_desc *desc;
8101                 __u64 addr, offs;
8102
8103                 if ((info_linear->arrays & (1UL << i)) == 0)
8104                         continue;
8105
8106                 desc = bpf_prog_info_array_desc + i;
8107                 addr = bpf_prog_info_read_offset_u64(&info_linear->info,
8108                                                      desc->array_offset);
8109                 offs = addr - ptr_to_u64(info_linear->data);
8110                 bpf_prog_info_set_offset_u64(&info_linear->info,
8111                                              desc->array_offset, offs);
8112         }
8113 }
8114
8115 void bpf_program__bpil_offs_to_addr(struct bpf_prog_info_linear *info_linear)
8116 {
8117         int i;
8118
8119         for (i = BPF_PROG_INFO_FIRST_ARRAY; i < BPF_PROG_INFO_LAST_ARRAY; ++i) {
8120                 struct bpf_prog_info_array_desc *desc;
8121                 __u64 addr, offs;
8122
8123                 if ((info_linear->arrays & (1UL << i)) == 0)
8124                         continue;
8125
8126                 desc = bpf_prog_info_array_desc + i;
8127                 offs = bpf_prog_info_read_offset_u64(&info_linear->info,
8128                                                      desc->array_offset);
8129                 addr = offs + ptr_to_u64(info_linear->data);
8130                 bpf_prog_info_set_offset_u64(&info_linear->info,
8131                                              desc->array_offset, addr);
8132         }
8133 }
8134
8135 int parse_cpu_mask_str(const char *s, bool **mask, int *mask_sz)
8136 {
8137         int err = 0, n, len, start, end = -1;
8138         bool *tmp;
8139
8140         *mask = NULL;
8141         *mask_sz = 0;
8142
8143         /* Each sub string separated by ',' has format \d+-\d+ or \d+ */
8144         while (*s) {
8145                 if (*s == ',' || *s == '\n') {
8146                         s++;
8147                         continue;
8148                 }
8149                 n = sscanf(s, "%d%n-%d%n", &start, &len, &end, &len);
8150                 if (n <= 0 || n > 2) {
8151                         pr_warn("Failed to get CPU range %s: %d\n", s, n);
8152                         err = -EINVAL;
8153                         goto cleanup;
8154                 } else if (n == 1) {
8155                         end = start;
8156                 }
8157                 if (start < 0 || start > end) {
8158                         pr_warn("Invalid CPU range [%d,%d] in %s\n",
8159                                 start, end, s);
8160                         err = -EINVAL;
8161                         goto cleanup;
8162                 }
8163                 tmp = realloc(*mask, end + 1);
8164                 if (!tmp) {
8165                         err = -ENOMEM;
8166                         goto cleanup;
8167                 }
8168                 *mask = tmp;
8169                 memset(tmp + *mask_sz, 0, start - *mask_sz);
8170                 memset(tmp + start, 1, end - start + 1);
8171                 *mask_sz = end + 1;
8172                 s += len;
8173         }
8174         if (!*mask_sz) {
8175                 pr_warn("Empty CPU range\n");
8176                 return -EINVAL;
8177         }
8178         return 0;
8179 cleanup:
8180         free(*mask);
8181         *mask = NULL;
8182         return err;
8183 }
8184
8185 int parse_cpu_mask_file(const char *fcpu, bool **mask, int *mask_sz)
8186 {
8187         int fd, err = 0, len;
8188         char buf[128];
8189
8190         fd = open(fcpu, O_RDONLY);
8191         if (fd < 0) {
8192                 err = -errno;
8193                 pr_warn("Failed to open cpu mask file %s: %d\n", fcpu, err);
8194                 return err;
8195         }
8196         len = read(fd, buf, sizeof(buf));
8197         close(fd);
8198         if (len <= 0) {
8199                 err = len ? -errno : -EINVAL;
8200                 pr_warn("Failed to read cpu mask from %s: %d\n", fcpu, err);
8201                 return err;
8202         }
8203         if (len >= sizeof(buf)) {
8204                 pr_warn("CPU mask is too big in file %s\n", fcpu);
8205                 return -E2BIG;
8206         }
8207         buf[len] = '\0';
8208
8209         return parse_cpu_mask_str(buf, mask, mask_sz);
8210 }
8211
8212 int libbpf_num_possible_cpus(void)
8213 {
8214         static const char *fcpu = "/sys/devices/system/cpu/possible";
8215         static int cpus;
8216         int err, n, i, tmp_cpus;
8217         bool *mask;
8218
8219         tmp_cpus = READ_ONCE(cpus);
8220         if (tmp_cpus > 0)
8221                 return tmp_cpus;
8222
8223         err = parse_cpu_mask_file(fcpu, &mask, &n);
8224         if (err)
8225                 return err;
8226
8227         tmp_cpus = 0;
8228         for (i = 0; i < n; i++) {
8229                 if (mask[i])
8230                         tmp_cpus++;
8231         }
8232         free(mask);
8233
8234         WRITE_ONCE(cpus, tmp_cpus);
8235         return tmp_cpus;
8236 }
8237
8238 int bpf_object__open_skeleton(struct bpf_object_skeleton *s,
8239                               const struct bpf_object_open_opts *opts)
8240 {
8241         DECLARE_LIBBPF_OPTS(bpf_object_open_opts, skel_opts,
8242                 .object_name = s->name,
8243         );
8244         struct bpf_object *obj;
8245         int i;
8246
8247         /* Attempt to preserve opts->object_name, unless overriden by user
8248          * explicitly. Overwriting object name for skeletons is discouraged,
8249          * as it breaks global data maps, because they contain object name
8250          * prefix as their own map name prefix. When skeleton is generated,
8251          * bpftool is making an assumption that this name will stay the same.
8252          */
8253         if (opts) {
8254                 memcpy(&skel_opts, opts, sizeof(*opts));
8255                 if (!opts->object_name)
8256                         skel_opts.object_name = s->name;
8257         }
8258
8259         obj = bpf_object__open_mem(s->data, s->data_sz, &skel_opts);
8260         if (IS_ERR(obj)) {
8261                 pr_warn("failed to initialize skeleton BPF object '%s': %ld\n",
8262                         s->name, PTR_ERR(obj));
8263                 return PTR_ERR(obj);
8264         }
8265
8266         *s->obj = obj;
8267
8268         for (i = 0; i < s->map_cnt; i++) {
8269                 struct bpf_map **map = s->maps[i].map;
8270                 const char *name = s->maps[i].name;
8271                 void **mmaped = s->maps[i].mmaped;
8272
8273                 *map = bpf_object__find_map_by_name(obj, name);
8274                 if (!*map) {
8275                         pr_warn("failed to find skeleton map '%s'\n", name);
8276                         return -ESRCH;
8277                 }
8278
8279                 /* externs shouldn't be pre-setup from user code */
8280                 if (mmaped && (*map)->libbpf_type != LIBBPF_MAP_KCONFIG)
8281                         *mmaped = (*map)->mmaped;
8282         }
8283
8284         for (i = 0; i < s->prog_cnt; i++) {
8285                 struct bpf_program **prog = s->progs[i].prog;
8286                 const char *name = s->progs[i].name;
8287
8288                 *prog = bpf_object__find_program_by_name(obj, name);
8289                 if (!*prog) {
8290                         pr_warn("failed to find skeleton program '%s'\n", name);
8291                         return -ESRCH;
8292                 }
8293         }
8294
8295         return 0;
8296 }
8297
8298 int bpf_object__load_skeleton(struct bpf_object_skeleton *s)
8299 {
8300         int i, err;
8301
8302         err = bpf_object__load(*s->obj);
8303         if (err) {
8304                 pr_warn("failed to load BPF skeleton '%s': %d\n", s->name, err);
8305                 return err;
8306         }
8307
8308         for (i = 0; i < s->map_cnt; i++) {
8309                 struct bpf_map *map = *s->maps[i].map;
8310                 size_t mmap_sz = bpf_map_mmap_sz(map);
8311                 int prot, map_fd = bpf_map__fd(map);
8312                 void **mmaped = s->maps[i].mmaped;
8313
8314                 if (!mmaped)
8315                         continue;
8316
8317                 if (!(map->def.map_flags & BPF_F_MMAPABLE)) {
8318                         *mmaped = NULL;
8319                         continue;
8320                 }
8321
8322                 if (map->def.map_flags & BPF_F_RDONLY_PROG)
8323                         prot = PROT_READ;
8324                 else
8325                         prot = PROT_READ | PROT_WRITE;
8326
8327                 /* Remap anonymous mmap()-ed "map initialization image" as
8328                  * a BPF map-backed mmap()-ed memory, but preserving the same
8329                  * memory address. This will cause kernel to change process'
8330                  * page table to point to a different piece of kernel memory,
8331                  * but from userspace point of view memory address (and its
8332                  * contents, being identical at this point) will stay the
8333                  * same. This mapping will be released by bpf_object__close()
8334                  * as per normal clean up procedure, so we don't need to worry
8335                  * about it from skeleton's clean up perspective.
8336                  */
8337                 *mmaped = mmap(map->mmaped, mmap_sz, prot,
8338                                 MAP_SHARED | MAP_FIXED, map_fd, 0);
8339                 if (*mmaped == MAP_FAILED) {
8340                         err = -errno;
8341                         *mmaped = NULL;
8342                         pr_warn("failed to re-mmap() map '%s': %d\n",
8343                                  bpf_map__name(map), err);
8344                         return err;
8345                 }
8346         }
8347
8348         return 0;
8349 }
8350
8351 int bpf_object__attach_skeleton(struct bpf_object_skeleton *s)
8352 {
8353         int i;
8354
8355         for (i = 0; i < s->prog_cnt; i++) {
8356                 struct bpf_program *prog = *s->progs[i].prog;
8357                 struct bpf_link **link = s->progs[i].link;
8358                 const struct bpf_sec_def *sec_def;
8359                 const char *sec_name = bpf_program__title(prog, false);
8360
8361                 sec_def = find_sec_def(sec_name);
8362                 if (!sec_def || !sec_def->attach_fn)
8363                         continue;
8364
8365                 *link = sec_def->attach_fn(sec_def, prog);
8366                 if (IS_ERR(*link)) {
8367                         pr_warn("failed to auto-attach program '%s': %ld\n",
8368                                 bpf_program__name(prog), PTR_ERR(*link));
8369                         return PTR_ERR(*link);
8370                 }
8371         }
8372
8373         return 0;
8374 }
8375
8376 void bpf_object__detach_skeleton(struct bpf_object_skeleton *s)
8377 {
8378         int i;
8379
8380         for (i = 0; i < s->prog_cnt; i++) {
8381                 struct bpf_link **link = s->progs[i].link;
8382
8383                 if (!IS_ERR_OR_NULL(*link))
8384                         bpf_link__destroy(*link);
8385                 *link = NULL;
8386         }
8387 }
8388
8389 void bpf_object__destroy_skeleton(struct bpf_object_skeleton *s)
8390 {
8391         if (s->progs)
8392                 bpf_object__detach_skeleton(s);
8393         if (s->obj)
8394                 bpf_object__close(*s->obj);
8395         free(s->maps);
8396         free(s->progs);
8397         free(s);
8398 }