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 <string.h>
  22 #include <unistd.h>
  23 #include <endian.h>
  24 #include <fcntl.h>
  25 #include <errno.h>
  26 #include <asm/unistd.h>
  27 #include <linux/err.h>
  28 #include <linux/kernel.h>
  29 #include <linux/bpf.h>
  30 #include <linux/btf.h>
  31 #include <linux/filter.h>
  32 #include <linux/list.h>
  33 #include <linux/limits.h>
  34 #include <linux/perf_event.h>
  35 #include <linux/ring_buffer.h>
  36 #include <sys/epoll.h>
  37 #include <sys/ioctl.h>
  38 #include <sys/mman.h>
  39 #include <sys/stat.h>
  40 #include <sys/types.h>
  41 #include <sys/vfs.h>
  42 #include <sys/utsname.h>
  43 #include <tools/libc_compat.h>
  44 #include <libelf.h>
  45 #include <gelf.h>
  46
  47 #include "libbpf.h"
  48 #include "bpf.h"
  49 #include "btf.h"
  50 #include "str_error.h"
  51 #include "libbpf_internal.h"
  52 #include "hashmap.h"
  53
  54 #ifndef EM_BPF
  55 #define EM_BPF 247
  56 #endif
  57
  58 #ifndef BPF_FS_MAGIC
  59 #define BPF_FS_MAGIC            0xcafe4a11
  60 #endif
  61
  62 /* vsprintf() in __base_pr() uses nonliteral format string. It may break
  63  * compilation if user enables corresponding warning. Disable it explicitly.
  64  */
  65 #pragma GCC diagnostic ignored "-Wformat-nonliteral"
  66
  67 #define __printf(a, b)  __attribute__((format(printf, a, b)))
  68
  69 static int __base_pr(enum libbpf_print_level level, const char *format,
  70                      va_list args)
  71 {
  72         if (level == LIBBPF_DEBUG)
  73                 return 0;
  74
  75         return vfprintf(stderr, format, args);
  76 }
  77
  78 static libbpf_print_fn_t __libbpf_pr = __base_pr;
  79
  80 libbpf_print_fn_t libbpf_set_print(libbpf_print_fn_t fn)
  81 {
  82         libbpf_print_fn_t old_print_fn = __libbpf_pr;
  83
  84         __libbpf_pr = fn;
  85         return old_print_fn;
  86 }
  87
  88 __printf(2, 3)
  89 void libbpf_print(enum libbpf_print_level level, const char *format, ...)
  90 {
  91         va_list args;
  92
  93         if (!__libbpf_pr)
  94                 return;
  95
  96         va_start(args, format);
  97         __libbpf_pr(level, format, args);
  98         va_end(args);
  99 }
 100
 101 #define STRERR_BUFSIZE  128
 102
 103 #define CHECK_ERR(action, err, out) do {        \
 104         err = action;                   \
 105         if (err)                        \
 106                 goto out;               \
 107 } while(0)
 108
 109
 110 /* Copied from tools/perf/util/util.h */
 111 #ifndef zfree
 112 # define zfree(ptr) ({ free(*ptr); *ptr = NULL; })
 113 #endif
 114
 115 #ifndef zclose
 116 # define zclose(fd) ({                  \
 117         int ___err = 0;                 \
 118         if ((fd) >= 0)                  \
 119                 ___err = close((fd));   \
 120         fd = -1;                        \
 121         ___err; })
 122 #endif
 123
 124 #ifdef HAVE_LIBELF_MMAP_SUPPORT
 125 # define LIBBPF_ELF_C_READ_MMAP ELF_C_READ_MMAP
 126 #else
 127 # define LIBBPF_ELF_C_READ_MMAP ELF_C_READ
 128 #endif
 129
 130 static inline __u64 ptr_to_u64(const void *ptr)
 131 {
 132         return (__u64) (unsigned long) ptr;
 133 }
 134
 135 struct bpf_capabilities {
 136         /* v4.14: kernel support for program & map names. */
 137         __u32 name:1;
 138         /* v5.2: kernel support for global data sections. */
 139         __u32 global_data:1;
 140         /* BTF_KIND_FUNC and BTF_KIND_FUNC_PROTO support */
 141         __u32 btf_func:1;
 142         /* BTF_KIND_VAR and BTF_KIND_DATASEC support */
 143         __u32 btf_datasec:1;
 144 };
 145
 146 /*
 147  * bpf_prog should be a better name but it has been used in
 148  * linux/filter.h.
 149  */
 150 struct bpf_program {
 151         /* Index in elf obj file, for relocation use. */
 152         int idx;
 153         char *name;
 154         int prog_ifindex;
 155         char *section_name;
 156         /* section_name with / replaced by _; makes recursive pinning
 157          * in bpf_object__pin_programs easier
 158          */
 159         char *pin_name;
 160         struct bpf_insn *insns;
 161         size_t insns_cnt, main_prog_cnt;
 162         enum bpf_prog_type type;
 163
 164         struct reloc_desc {
 165                 enum {
 166                         RELO_LD64,
 167                         RELO_CALL,
 168                         RELO_DATA,
 169                 } type;
 170                 int insn_idx;
 171                 union {
 172                         int map_idx;
 173                         int text_off;
 174                 };
 175         } *reloc_desc;
 176         int nr_reloc;
 177         int log_level;
 178
 179         struct {
 180                 int nr;
 181                 int *fds;
 182         } instances;
 183         bpf_program_prep_t preprocessor;
 184
 185         struct bpf_object *obj;
 186         void *priv;
 187         bpf_program_clear_priv_t clear_priv;
 188
 189         enum bpf_attach_type expected_attach_type;
 190         void *func_info;
 191         __u32 func_info_rec_size;
 192         __u32 func_info_cnt;
 193
 194         struct bpf_capabilities *caps;
 195
 196         void *line_info;
 197         __u32 line_info_rec_size;
 198         __u32 line_info_cnt;
 199         __u32 prog_flags;
 200 };
 201
 202 enum libbpf_map_type {
 203         LIBBPF_MAP_UNSPEC,
 204         LIBBPF_MAP_DATA,
 205         LIBBPF_MAP_BSS,
 206         LIBBPF_MAP_RODATA,
 207 };
 208
 209 static const char * const libbpf_type_to_btf_name[] = {
 210         [LIBBPF_MAP_DATA]       = ".data",
 211         [LIBBPF_MAP_BSS]        = ".bss",
 212         [LIBBPF_MAP_RODATA]     = ".rodata",
 213 };
 214
 215 struct bpf_map {
 216         int fd;
 217         char *name;
 218         int sec_idx;
 219         size_t sec_offset;
 220         int map_ifindex;
 221         int inner_map_fd;
 222         struct bpf_map_def def;
 223         __u32 btf_key_type_id;
 224         __u32 btf_value_type_id;
 225         void *priv;
 226         bpf_map_clear_priv_t clear_priv;
 227         enum libbpf_map_type libbpf_type;
 228 };
 229
 230 struct bpf_secdata {
 231         void *rodata;
 232         void *data;
 233 };
 234
 235 static LIST_HEAD(bpf_objects_list);
 236
 237 struct bpf_object {
 238         char name[BPF_OBJ_NAME_LEN];
 239         char license[64];
 240         __u32 kern_version;
 241
 242         struct bpf_program *programs;
 243         size_t nr_programs;
 244         struct bpf_map *maps;
 245         size_t nr_maps;
 246         size_t maps_cap;
 247         struct bpf_secdata sections;
 248
 249         bool loaded;
 250         bool has_pseudo_calls;
 251
 252         /*
 253          * Information when doing elf related work. Only valid if fd
 254          * is valid.
 255          */
 256         struct {
 257                 int fd;
 258                 void *obj_buf;
 259                 size_t obj_buf_sz;
 260                 Elf *elf;
 261                 GElf_Ehdr ehdr;
 262                 Elf_Data *symbols;
 263                 Elf_Data *data;
 264                 Elf_Data *rodata;
 265                 Elf_Data *bss;
 266                 size_t strtabidx;
 267                 struct {
 268                         GElf_Shdr shdr;
 269                         Elf_Data *data;
 270                 } *reloc;
 271                 int nr_reloc;
 272                 int maps_shndx;
 273                 int btf_maps_shndx;
 274                 int text_shndx;
 275                 int data_shndx;
 276                 int rodata_shndx;
 277                 int bss_shndx;
 278         } efile;
 279         /*
 280          * All loaded bpf_object is linked in a list, which is
 281          * hidden to caller. bpf_objects__<func> handlers deal with
 282          * all objects.
 283          */
 284         struct list_head list;
 285
 286         struct btf *btf;
 287         struct btf_ext *btf_ext;
 288
 289         void *priv;
 290         bpf_object_clear_priv_t clear_priv;
 291
 292         struct bpf_capabilities caps;
 293
 294         char path[];
 295 };
 296 #define obj_elf_valid(o)        ((o)->efile.elf)
 297
 298 void bpf_program__unload(struct bpf_program *prog)
 299 {
 300         int i;
 301
 302         if (!prog)
 303                 return;
 304
 305         /*
 306          * If the object is opened but the program was never loaded,
 307          * it is possible that prog->instances.nr == -1.
 308          */
 309         if (prog->instances.nr > 0) {
 310                 for (i = 0; i < prog->instances.nr; i++)
 311                         zclose(prog->instances.fds[i]);
 312         } else if (prog->instances.nr != -1) {
 313                 pr_warning("Internal error: instances.nr is %d\n",
 314                            prog->instances.nr);
 315         }
 316
 317         prog->instances.nr = -1;
 318         zfree(&prog->instances.fds);
 319
 320         zfree(&prog->func_info);
 321         zfree(&prog->line_info);
 322 }
 323
 324 static void bpf_program__exit(struct bpf_program *prog)
 325 {
 326         if (!prog)
 327                 return;
 328
 329         if (prog->clear_priv)
 330                 prog->clear_priv(prog, prog->priv);
 331
 332         prog->priv = NULL;
 333         prog->clear_priv = NULL;
 334
 335         bpf_program__unload(prog);
 336         zfree(&prog->name);
 337         zfree(&prog->section_name);
 338         zfree(&prog->pin_name);
 339         zfree(&prog->insns);
 340         zfree(&prog->reloc_desc);
 341
 342         prog->nr_reloc = 0;
 343         prog->insns_cnt = 0;
 344         prog->idx = -1;
 345 }
 346
 347 static char *__bpf_program__pin_name(struct bpf_program *prog)
 348 {
 349         char *name, *p;
 350
 351         name = p = strdup(prog->section_name);
 352         while ((p = strchr(p, '/')))
 353                 *p = '_';
 354
 355         return name;
 356 }
 357
 358 static int
 359 bpf_program__init(void *data, size_t size, char *section_name, int idx,
 360                   struct bpf_program *prog)
 361 {
 362         const size_t bpf_insn_sz = sizeof(struct bpf_insn);
 363
 364         if (size == 0 || size % bpf_insn_sz) {
 365                 pr_warning("corrupted section '%s', size: %zu\n",
 366                            section_name, size);
 367                 return -EINVAL;
 368         }
 369
 370         memset(prog, 0, sizeof(*prog));
 371
 372         prog->section_name = strdup(section_name);
 373         if (!prog->section_name) {
 374                 pr_warning("failed to alloc name for prog under section(%d) %s\n",
 375                            idx, section_name);
 376                 goto errout;
 377         }
 378
 379         prog->pin_name = __bpf_program__pin_name(prog);
 380         if (!prog->pin_name) {
 381                 pr_warning("failed to alloc pin name for prog under section(%d) %s\n",
 382                            idx, section_name);
 383                 goto errout;
 384         }
 385
 386         prog->insns = malloc(size);
 387         if (!prog->insns) {
 388                 pr_warning("failed to alloc insns for prog under section %s\n",
 389                            section_name);
 390                 goto errout;
 391         }
 392         prog->insns_cnt = size / bpf_insn_sz;
 393         memcpy(prog->insns, data, size);
 394         prog->idx = idx;
 395         prog->instances.fds = NULL;
 396         prog->instances.nr = -1;
 397         prog->type = BPF_PROG_TYPE_UNSPEC;
 398
 399         return 0;
 400 errout:
 401         bpf_program__exit(prog);
 402         return -ENOMEM;
 403 }
 404
 405 static int
 406 bpf_object__add_program(struct bpf_object *obj, void *data, size_t size,
 407                         char *section_name, int idx)
 408 {
 409         struct bpf_program prog, *progs;
 410         int nr_progs, err;
 411
 412         err = bpf_program__init(data, size, section_name, idx, &prog);
 413         if (err)
 414                 return err;
 415
 416         prog.caps = &obj->caps;
 417         progs = obj->programs;
 418         nr_progs = obj->nr_programs;
 419
 420         progs = reallocarray(progs, nr_progs + 1, sizeof(progs[0]));
 421         if (!progs) {
 422                 /*
 423                  * In this case the original obj->programs
 424                  * is still valid, so don't need special treat for
 425                  * bpf_close_object().
 426                  */
 427                 pr_warning("failed to alloc a new program under section '%s'\n",
 428                            section_name);
 429                 bpf_program__exit(&prog);
 430                 return -ENOMEM;
 431         }
 432
 433         pr_debug("found program %s\n", prog.section_name);
 434         obj->programs = progs;
 435         obj->nr_programs = nr_progs + 1;
 436         prog.obj = obj;
 437         progs[nr_progs] = prog;
 438         return 0;
 439 }
 440
 441 static int
 442 bpf_object__init_prog_names(struct bpf_object *obj)
 443 {
 444         Elf_Data *symbols = obj->efile.symbols;
 445         struct bpf_program *prog;
 446         size_t pi, si;
 447
 448         for (pi = 0; pi < obj->nr_programs; pi++) {
 449                 const char *name = NULL;
 450
 451                 prog = &obj->programs[pi];
 452
 453                 for (si = 0; si < symbols->d_size / sizeof(GElf_Sym) && !name;
 454                      si++) {
 455                         GElf_Sym sym;
 456
 457                         if (!gelf_getsym(symbols, si, &sym))
 458                                 continue;
 459                         if (sym.st_shndx != prog->idx)
 460                                 continue;
 461                         if (GELF_ST_BIND(sym.st_info) != STB_GLOBAL)
 462                                 continue;
 463
 464                         name = elf_strptr(obj->efile.elf,
 465                                           obj->efile.strtabidx,
 466                                           sym.st_name);
 467                         if (!name) {
 468                                 pr_warning("failed to get sym name string for prog %s\n",
 469                                            prog->section_name);
 470                                 return -LIBBPF_ERRNO__LIBELF;
 471                         }
 472                 }
 473
 474                 if (!name && prog->idx == obj->efile.text_shndx)
 475                         name = ".text";
 476
 477                 if (!name) {
 478                         pr_warning("failed to find sym for prog %s\n",
 479                                    prog->section_name);
 480                         return -EINVAL;
 481                 }
 482
 483                 prog->name = strdup(name);
 484                 if (!prog->name) {
 485                         pr_warning("failed to allocate memory for prog sym %s\n",
 486                                    name);
 487                         return -ENOMEM;
 488                 }
 489         }
 490
 491         return 0;
 492 }
 493
 494 static struct bpf_object *bpf_object__new(const char *path,
 495                                           void *obj_buf,
 496                                           size_t obj_buf_sz)
 497 {
 498         struct bpf_object *obj;
 499         char *end;
 500
 501         obj = calloc(1, sizeof(struct bpf_object) + strlen(path) + 1);
 502         if (!obj) {
 503                 pr_warning("alloc memory failed for %s\n", path);
 504                 return ERR_PTR(-ENOMEM);
 505         }
 506
 507         strcpy(obj->path, path);
 508         /* Using basename() GNU version which doesn't modify arg. */
 509         strncpy(obj->name, basename((void *)path), sizeof(obj->name) - 1);
 510         end = strchr(obj->name, '.');
 511         if (end)
 512                 *end = 0;
 513
 514         obj->efile.fd = -1;
 515         /*
 516          * Caller of this function should also call
 517          * bpf_object__elf_finish() after data collection to return
 518          * obj_buf to user. If not, we should duplicate the buffer to
 519          * avoid user freeing them before elf finish.
 520          */
 521         obj->efile.obj_buf = obj_buf;
 522         obj->efile.obj_buf_sz = obj_buf_sz;
 523         obj->efile.maps_shndx = -1;
 524         obj->efile.btf_maps_shndx = -1;
 525         obj->efile.data_shndx = -1;
 526         obj->efile.rodata_shndx = -1;
 527         obj->efile.bss_shndx = -1;
 528
 529         obj->loaded = false;
 530
 531         INIT_LIST_HEAD(&obj->list);
 532         list_add(&obj->list, &bpf_objects_list);
 533         return obj;
 534 }
 535
 536 static void bpf_object__elf_finish(struct bpf_object *obj)
 537 {
 538         if (!obj_elf_valid(obj))
 539                 return;
 540
 541         if (obj->efile.elf) {
 542                 elf_end(obj->efile.elf);
 543                 obj->efile.elf = NULL;
 544         }
 545         obj->efile.symbols = NULL;
 546         obj->efile.data = NULL;
 547         obj->efile.rodata = NULL;
 548         obj->efile.bss = NULL;
 549
 550         zfree(&obj->efile.reloc);
 551         obj->efile.nr_reloc = 0;
 552         zclose(obj->efile.fd);
 553         obj->efile.obj_buf = NULL;
 554         obj->efile.obj_buf_sz = 0;
 555 }
 556
 557 static int bpf_object__elf_init(struct bpf_object *obj)
 558 {
 559         int err = 0;
 560         GElf_Ehdr *ep;
 561
 562         if (obj_elf_valid(obj)) {
 563                 pr_warning("elf init: internal error\n");
 564                 return -LIBBPF_ERRNO__LIBELF;
 565         }
 566
 567         if (obj->efile.obj_buf_sz > 0) {
 568                 /*
 569                  * obj_buf should have been validated by
 570                  * bpf_object__open_buffer().
 571                  */
 572                 obj->efile.elf = elf_memory(obj->efile.obj_buf,
 573                                             obj->efile.obj_buf_sz);
 574         } else {
 575                 obj->efile.fd = open(obj->path, O_RDONLY);
 576                 if (obj->efile.fd < 0) {
 577                         char errmsg[STRERR_BUFSIZE], *cp;
 578
 579                         err = -errno;
 580                         cp = libbpf_strerror_r(err, errmsg, sizeof(errmsg));
 581                         pr_warning("failed to open %s: %s\n", obj->path, cp);
 582                         return err;
 583                 }
 584
 585                 obj->efile.elf = elf_begin(obj->efile.fd,
 586                                            LIBBPF_ELF_C_READ_MMAP, NULL);
 587         }
 588
 589         if (!obj->efile.elf) {
 590                 pr_warning("failed to open %s as ELF file\n", obj->path);
 591                 err = -LIBBPF_ERRNO__LIBELF;
 592                 goto errout;
 593         }
 594
 595         if (!gelf_getehdr(obj->efile.elf, &obj->efile.ehdr)) {
 596                 pr_warning("failed to get EHDR from %s\n", obj->path);
 597                 err = -LIBBPF_ERRNO__FORMAT;
 598                 goto errout;
 599         }
 600         ep = &obj->efile.ehdr;
 601
 602         /* Old LLVM set e_machine to EM_NONE */
 603         if (ep->e_type != ET_REL ||
 604             (ep->e_machine && ep->e_machine != EM_BPF)) {
 605                 pr_warning("%s is not an eBPF object file\n", obj->path);
 606                 err = -LIBBPF_ERRNO__FORMAT;
 607                 goto errout;
 608         }
 609
 610         return 0;
 611 errout:
 612         bpf_object__elf_finish(obj);
 613         return err;
 614 }
 615
 616 static int bpf_object__check_endianness(struct bpf_object *obj)
 617 {
 618 #if __BYTE_ORDER == __LITTLE_ENDIAN
 619         if (obj->efile.ehdr.e_ident[EI_DATA] == ELFDATA2LSB)
 620                 return 0;
 621 #elif __BYTE_ORDER == __BIG_ENDIAN
 622         if (obj->efile.ehdr.e_ident[EI_DATA] == ELFDATA2MSB)
 623                 return 0;
 624 #else
 625 # error "Unrecognized __BYTE_ORDER__"
 626 #endif
 627         pr_warning("endianness mismatch.\n");
 628         return -LIBBPF_ERRNO__ENDIAN;
 629 }
 630
 631 static int
 632 bpf_object__init_license(struct bpf_object *obj, void *data, size_t size)
 633 {
 634         memcpy(obj->license, data, min(size, sizeof(obj->license) - 1));
 635         pr_debug("license of %s is %s\n", obj->path, obj->license);
 636         return 0;
 637 }
 638
 639 static int
 640 bpf_object__init_kversion(struct bpf_object *obj, void *data, size_t size)
 641 {
 642         __u32 kver;
 643
 644         if (size != sizeof(kver)) {
 645                 pr_warning("invalid kver section in %s\n", obj->path);
 646                 return -LIBBPF_ERRNO__FORMAT;
 647         }
 648         memcpy(&kver, data, sizeof(kver));
 649         obj->kern_version = kver;
 650         pr_debug("kernel version of %s is %x\n", obj->path, obj->kern_version);
 651         return 0;
 652 }
 653
 654 static int compare_bpf_map(const void *_a, const void *_b)
 655 {
 656         const struct bpf_map *a = _a;
 657         const struct bpf_map *b = _b;
 658
 659         if (a->sec_idx != b->sec_idx)
 660                 return a->sec_idx - b->sec_idx;
 661         return a->sec_offset - b->sec_offset;
 662 }
 663
 664 static bool bpf_map_type__is_map_in_map(enum bpf_map_type type)
 665 {
 666         if (type == BPF_MAP_TYPE_ARRAY_OF_MAPS ||
 667             type == BPF_MAP_TYPE_HASH_OF_MAPS)
 668                 return true;
 669         return false;
 670 }
 671
 672 static int bpf_object_search_section_size(const struct bpf_object *obj,
 673                                           const char *name, size_t *d_size)
 674 {
 675         const GElf_Ehdr *ep = &obj->efile.ehdr;
 676         Elf *elf = obj->efile.elf;
 677         Elf_Scn *scn = NULL;
 678         int idx = 0;
 679
 680         while ((scn = elf_nextscn(elf, scn)) != NULL) {
 681                 const char *sec_name;
 682                 Elf_Data *data;
 683                 GElf_Shdr sh;
 684
 685                 idx++;
 686                 if (gelf_getshdr(scn, &sh) != &sh) {
 687                         pr_warning("failed to get section(%d) header from %s\n",
 688                                    idx, obj->path);
 689                         return -EIO;
 690                 }
 691
 692                 sec_name = elf_strptr(elf, ep->e_shstrndx, sh.sh_name);
 693                 if (!sec_name) {
 694                         pr_warning("failed to get section(%d) name from %s\n",
 695                                    idx, obj->path);
 696                         return -EIO;
 697                 }
 698
 699                 if (strcmp(name, sec_name))
 700                         continue;
 701
 702                 data = elf_getdata(scn, 0);
 703                 if (!data) {
 704                         pr_warning("failed to get section(%d) data from %s(%s)\n",
 705                                    idx, name, obj->path);
 706                         return -EIO;
 707                 }
 708
 709                 *d_size = data->d_size;
 710                 return 0;
 711         }
 712
 713         return -ENOENT;
 714 }
 715
 716 int bpf_object__section_size(const struct bpf_object *obj, const char *name,
 717                              __u32 *size)
 718 {
 719         int ret = -ENOENT;
 720         size_t d_size;
 721
 722         *size = 0;
 723         if (!name) {
 724                 return -EINVAL;
 725         } else if (!strcmp(name, ".data")) {
 726                 if (obj->efile.data)
 727                         *size = obj->efile.data->d_size;
 728         } else if (!strcmp(name, ".bss")) {
 729                 if (obj->efile.bss)
 730                         *size = obj->efile.bss->d_size;
 731         } else if (!strcmp(name, ".rodata")) {
 732                 if (obj->efile.rodata)
 733                         *size = obj->efile.rodata->d_size;
 734         } else {
 735                 ret = bpf_object_search_section_size(obj, name, &d_size);
 736                 if (!ret)
 737                         *size = d_size;
 738         }
 739
 740         return *size ? 0 : ret;
 741 }
 742
 743 int bpf_object__variable_offset(const struct bpf_object *obj, const char *name,
 744                                 __u32 *off)
 745 {
 746         Elf_Data *symbols = obj->efile.symbols;
 747         const char *sname;
 748         size_t si;
 749
 750         if (!name || !off)
 751                 return -EINVAL;
 752
 753         for (si = 0; si < symbols->d_size / sizeof(GElf_Sym); si++) {
 754                 GElf_Sym sym;
 755
 756                 if (!gelf_getsym(symbols, si, &sym))
 757                         continue;
 758                 if (GELF_ST_BIND(sym.st_info) != STB_GLOBAL ||
 759                     GELF_ST_TYPE(sym.st_info) != STT_OBJECT)
 760                         continue;
 761
 762                 sname = elf_strptr(obj->efile.elf, obj->efile.strtabidx,
 763                                    sym.st_name);
 764                 if (!sname) {
 765                         pr_warning("failed to get sym name string for var %s\n",
 766                                    name);
 767                         return -EIO;
 768                 }
 769                 if (strcmp(name, sname) == 0) {
 770                         *off = sym.st_value;
 771                         return 0;
 772                 }
 773         }
 774
 775         return -ENOENT;
 776 }
 777
 778 static struct bpf_map *bpf_object__add_map(struct bpf_object *obj)
 779 {
 780         struct bpf_map *new_maps;
 781         size_t new_cap;
 782         int i;
 783
 784         if (obj->nr_maps < obj->maps_cap)
 785                 return &obj->maps[obj->nr_maps++];
 786
 787         new_cap = max((size_t)4, obj->maps_cap * 3 / 2);
 788         new_maps = realloc(obj->maps, new_cap * sizeof(*obj->maps));
 789         if (!new_maps) {
 790                 pr_warning("alloc maps for object failed\n");
 791                 return ERR_PTR(-ENOMEM);
 792         }
 793
 794         obj->maps_cap = new_cap;
 795         obj->maps = new_maps;
 796
 797         /* zero out new maps */
 798         memset(obj->maps + obj->nr_maps, 0,
 799                (obj->maps_cap - obj->nr_maps) * sizeof(*obj->maps));
 800         /*
 801          * fill all fd with -1 so won't close incorrect fd (fd=0 is stdin)
 802          * when failure (zclose won't close negative fd)).
 803          */
 804         for (i = obj->nr_maps; i < obj->maps_cap; i++) {
 805                 obj->maps[i].fd = -1;
 806                 obj->maps[i].inner_map_fd = -1;
 807         }
 808
 809         return &obj->maps[obj->nr_maps++];
 810 }
 811
 812 static int
 813 bpf_object__init_internal_map(struct bpf_object *obj, enum libbpf_map_type type,
 814                               int sec_idx, Elf_Data *data, void **data_buff)
 815 {
 816         char map_name[BPF_OBJ_NAME_LEN];
 817         struct bpf_map_def *def;
 818         struct bpf_map *map;
 819
 820         map = bpf_object__add_map(obj);
 821         if (IS_ERR(map))
 822                 return PTR_ERR(map);
 823
 824         map->libbpf_type = type;
 825         map->sec_idx = sec_idx;
 826         map->sec_offset = 0;
 827         snprintf(map_name, sizeof(map_name), "%.8s%.7s", obj->name,
 828                  libbpf_type_to_btf_name[type]);
 829         map->name = strdup(map_name);
 830         if (!map->name) {
 831                 pr_warning("failed to alloc map name\n");
 832                 return -ENOMEM;
 833         }
 834         pr_debug("map '%s' (global data): at sec_idx %d, offset %zu.\n",
 835                  map_name, map->sec_idx, map->sec_offset);
 836
 837         def = &map->def;
 838         def->type = BPF_MAP_TYPE_ARRAY;
 839         def->key_size = sizeof(int);
 840         def->value_size = data->d_size;
 841         def->max_entries = 1;
 842         def->map_flags = type == LIBBPF_MAP_RODATA ? BPF_F_RDONLY_PROG : 0;
 843         if (data_buff) {
 844                 *data_buff = malloc(data->d_size);
 845                 if (!*data_buff) {
 846                         zfree(&map->name);
 847                         pr_warning("failed to alloc map content buffer\n");
 848                         return -ENOMEM;
 849                 }
 850                 memcpy(*data_buff, data->d_buf, data->d_size);
 851         }
 852
 853         pr_debug("map %td is \"%s\"\n", map - obj->maps, map->name);
 854         return 0;
 855 }
 856
 857 static int bpf_object__init_global_data_maps(struct bpf_object *obj)
 858 {
 859         int err;
 860
 861         if (!obj->caps.global_data)
 862                 return 0;
 863         /*
 864          * Populate obj->maps with libbpf internal maps.
 865          */
 866         if (obj->efile.data_shndx >= 0) {
 867                 err = bpf_object__init_internal_map(obj, LIBBPF_MAP_DATA,
 868                                                     obj->efile.data_shndx,
 869                                                     obj->efile.data,
 870                                                     &obj->sections.data);
 871                 if (err)
 872                         return err;
 873         }
 874         if (obj->efile.rodata_shndx >= 0) {
 875                 err = bpf_object__init_internal_map(obj, LIBBPF_MAP_RODATA,
 876                                                     obj->efile.rodata_shndx,
 877                                                     obj->efile.rodata,
 878                                                     &obj->sections.rodata);
 879                 if (err)
 880                         return err;
 881         }
 882         if (obj->efile.bss_shndx >= 0) {
 883                 err = bpf_object__init_internal_map(obj, LIBBPF_MAP_BSS,
 884                                                     obj->efile.bss_shndx,
 885                                                     obj->efile.bss, NULL);
 886                 if (err)
 887                         return err;
 888         }
 889         return 0;
 890 }
 891
 892 static int bpf_object__init_user_maps(struct bpf_object *obj, bool strict)
 893 {
 894         Elf_Data *symbols = obj->efile.symbols;
 895         int i, map_def_sz = 0, nr_maps = 0, nr_syms;
 896         Elf_Data *data = NULL;
 897         Elf_Scn *scn;
 898
 899         if (obj->efile.maps_shndx < 0)
 900                 return 0;
 901
 902         if (!symbols)
 903                 return -EINVAL;
 904
 905         scn = elf_getscn(obj->efile.elf, obj->efile.maps_shndx);
 906         if (scn)
 907                 data = elf_getdata(scn, NULL);
 908         if (!scn || !data) {
 909                 pr_warning("failed to get Elf_Data from map section %d\n",
 910                            obj->efile.maps_shndx);
 911                 return -EINVAL;
 912         }
 913
 914         /*
 915          * Count number of maps. Each map has a name.
 916          * Array of maps is not supported: only the first element is
 917          * considered.
 918          *
 919          * TODO: Detect array of map and report error.
 920          */
 921         nr_syms = symbols->d_size / sizeof(GElf_Sym);
 922         for (i = 0; i < nr_syms; i++) {
 923                 GElf_Sym sym;
 924
 925                 if (!gelf_getsym(symbols, i, &sym))
 926                         continue;
 927                 if (sym.st_shndx != obj->efile.maps_shndx)
 928                         continue;
 929                 nr_maps++;
 930         }
 931         /* Assume equally sized map definitions */
 932         pr_debug("maps in %s: %d maps in %zd bytes\n",
 933                  obj->path, nr_maps, data->d_size);
 934
 935         map_def_sz = data->d_size / nr_maps;
 936         if (!data->d_size || (data->d_size % nr_maps) != 0) {
 937                 pr_warning("unable to determine map definition size "
 938                            "section %s, %d maps in %zd bytes\n",
 939                            obj->path, nr_maps, data->d_size);
 940                 return -EINVAL;
 941         }
 942
 943         /* Fill obj->maps using data in "maps" section.  */
 944         for (i = 0; i < nr_syms; i++) {
 945                 GElf_Sym sym;
 946                 const char *map_name;
 947                 struct bpf_map_def *def;
 948                 struct bpf_map *map;
 949
 950                 if (!gelf_getsym(symbols, i, &sym))
 951                         continue;
 952                 if (sym.st_shndx != obj->efile.maps_shndx)
 953                         continue;
 954
 955                 map = bpf_object__add_map(obj);
 956                 if (IS_ERR(map))
 957                         return PTR_ERR(map);
 958
 959                 map_name = elf_strptr(obj->efile.elf, obj->efile.strtabidx,
 960                                       sym.st_name);
 961                 if (!map_name) {
 962                         pr_warning("failed to get map #%d name sym string for obj %s\n",
 963                                    i, obj->path);
 964                         return -LIBBPF_ERRNO__FORMAT;
 965                 }
 966
 967                 map->libbpf_type = LIBBPF_MAP_UNSPEC;
 968                 map->sec_idx = sym.st_shndx;
 969                 map->sec_offset = sym.st_value;
 970                 pr_debug("map '%s' (legacy): at sec_idx %d, offset %zu.\n",
 971                          map_name, map->sec_idx, map->sec_offset);
 972                 if (sym.st_value + map_def_sz > data->d_size) {
 973                         pr_warning("corrupted maps section in %s: last map \"%s\" too small\n",
 974                                    obj->path, map_name);
 975                         return -EINVAL;
 976                 }
 977
 978                 map->name = strdup(map_name);
 979                 if (!map->name) {
 980                         pr_warning("failed to alloc map name\n");
 981                         return -ENOMEM;
 982                 }
 983                 pr_debug("map %d is \"%s\"\n", i, map->name);
 984                 def = (struct bpf_map_def *)(data->d_buf + sym.st_value);
 985                 /*
 986                  * If the definition of the map in the object file fits in
 987                  * bpf_map_def, copy it.  Any extra fields in our version
 988                  * of bpf_map_def will default to zero as a result of the
 989                  * calloc above.
 990                  */
 991                 if (map_def_sz <= sizeof(struct bpf_map_def)) {
 992                         memcpy(&map->def, def, map_def_sz);
 993                 } else {
 994                         /*
 995                          * Here the map structure being read is bigger than what
 996                          * we expect, truncate if the excess bits are all zero.
 997                          * If they are not zero, reject this map as
 998                          * incompatible.
 999                          */
1000                         char *b;
1001                         for (b = ((char *)def) + sizeof(struct bpf_map_def);
1002                              b < ((char *)def) + map_def_sz; b++) {
1003                                 if (*b != 0) {
1004                                         pr_warning("maps section in %s: \"%s\" "
1005                                                    "has unrecognized, non-zero "
1006                                                    "options\n",
1007                                                    obj->path, map_name);
1008                                         if (strict)
1009                                                 return -EINVAL;
1010                                 }
1011                         }
1012                         memcpy(&map->def, def, sizeof(struct bpf_map_def));
1013                 }
1014         }
1015         return 0;
1016 }
1017
1018 static const struct btf_type *
1019 skip_mods_and_typedefs(const struct btf *btf, __u32 id, __u32 *res_id)
1020 {
1021         const struct btf_type *t = btf__type_by_id(btf, id);
1022
1023         if (res_id)
1024                 *res_id = id;
1025
1026         while (btf_is_mod(t) || btf_is_typedef(t)) {
1027                 if (res_id)
1028                         *res_id = t->type;
1029                 t = btf__type_by_id(btf, t->type);
1030         }
1031
1032         return t;
1033 }
1034
1035 /*
1036  * Fetch integer attribute of BTF map definition. Such attributes are
1037  * represented using a pointer to an array, in which dimensionality of array
1038  * encodes specified integer value. E.g., int (*type)[BPF_MAP_TYPE_ARRAY];
1039  * encodes `type => BPF_MAP_TYPE_ARRAY` key/value pair completely using BTF
1040  * type definition, while using only sizeof(void *) space in ELF data section.
1041  */
1042 static bool get_map_field_int(const char *map_name, const struct btf *btf,
1043                               const struct btf_type *def,
1044                               const struct btf_member *m, __u32 *res) {
1045         const struct btf_type *t = skip_mods_and_typedefs(btf, m->type, NULL);
1046         const char *name = btf__name_by_offset(btf, m->name_off);
1047         const struct btf_array *arr_info;
1048         const struct btf_type *arr_t;
1049
1050         if (!btf_is_ptr(t)) {
1051                 pr_warning("map '%s': attr '%s': expected PTR, got %u.\n",
1052                            map_name, name, btf_kind(t));
1053                 return false;
1054         }
1055
1056         arr_t = btf__type_by_id(btf, t->type);
1057         if (!arr_t) {
1058                 pr_warning("map '%s': attr '%s': type [%u] not found.\n",
1059                            map_name, name, t->type);
1060                 return false;
1061         }
1062         if (!btf_is_array(arr_t)) {
1063                 pr_warning("map '%s': attr '%s': expected ARRAY, got %u.\n",
1064                            map_name, name, btf_kind(arr_t));
1065                 return false;
1066         }
1067         arr_info = btf_array(arr_t);
1068         *res = arr_info->nelems;
1069         return true;
1070 }
1071
1072 static int bpf_object__init_user_btf_map(struct bpf_object *obj,
1073                                          const struct btf_type *sec,
1074                                          int var_idx, int sec_idx,
1075                                          const Elf_Data *data, bool strict)
1076 {
1077         const struct btf_type *var, *def, *t;
1078         const struct btf_var_secinfo *vi;
1079         const struct btf_var *var_extra;
1080         const struct btf_member *m;
1081         const char *map_name;
1082         struct bpf_map *map;
1083         int vlen, i;
1084
1085         vi = btf_var_secinfos(sec) + var_idx;
1086         var = btf__type_by_id(obj->btf, vi->type);
1087         var_extra = btf_var(var);
1088         map_name = btf__name_by_offset(obj->btf, var->name_off);
1089         vlen = btf_vlen(var);
1090
1091         if (map_name == NULL || map_name[0] == '\0') {
1092                 pr_warning("map #%d: empty name.\n", var_idx);
1093                 return -EINVAL;
1094         }
1095         if ((__u64)vi->offset + vi->size > data->d_size) {
1096                 pr_warning("map '%s' BTF data is corrupted.\n", map_name);
1097                 return -EINVAL;
1098         }
1099         if (!btf_is_var(var)) {
1100                 pr_warning("map '%s': unexpected var kind %u.\n",
1101                            map_name, btf_kind(var));
1102                 return -EINVAL;
1103         }
1104         if (var_extra->linkage != BTF_VAR_GLOBAL_ALLOCATED &&
1105             var_extra->linkage != BTF_VAR_STATIC) {
1106                 pr_warning("map '%s': unsupported var linkage %u.\n",
1107                            map_name, var_extra->linkage);
1108                 return -EOPNOTSUPP;
1109         }
1110
1111         def = skip_mods_and_typedefs(obj->btf, var->type, NULL);
1112         if (!btf_is_struct(def)) {
1113                 pr_warning("map '%s': unexpected def kind %u.\n",
1114                            map_name, btf_kind(var));
1115                 return -EINVAL;
1116         }
1117         if (def->size > vi->size) {
1118                 pr_warning("map '%s': invalid def size.\n", map_name);
1119                 return -EINVAL;
1120         }
1121
1122         map = bpf_object__add_map(obj);
1123         if (IS_ERR(map))
1124                 return PTR_ERR(map);
1125         map->name = strdup(map_name);
1126         if (!map->name) {
1127                 pr_warning("map '%s': failed to alloc map name.\n", map_name);
1128                 return -ENOMEM;
1129         }
1130         map->libbpf_type = LIBBPF_MAP_UNSPEC;
1131         map->def.type = BPF_MAP_TYPE_UNSPEC;
1132         map->sec_idx = sec_idx;
1133         map->sec_offset = vi->offset;
1134         pr_debug("map '%s': at sec_idx %d, offset %zu.\n",
1135                  map_name, map->sec_idx, map->sec_offset);
1136
1137         vlen = btf_vlen(def);
1138         m = btf_members(def);
1139         for (i = 0; i < vlen; i++, m++) {
1140                 const char *name = btf__name_by_offset(obj->btf, m->name_off);
1141
1142                 if (!name) {
1143                         pr_warning("map '%s': invalid field #%d.\n",
1144                                    map_name, i);
1145                         return -EINVAL;
1146                 }
1147                 if (strcmp(name, "type") == 0) {
1148                         if (!get_map_field_int(map_name, obj->btf, def, m,
1149                                                &map->def.type))
1150                                 return -EINVAL;
1151                         pr_debug("map '%s': found type = %u.\n",
1152                                  map_name, map->def.type);
1153                 } else if (strcmp(name, "max_entries") == 0) {
1154                         if (!get_map_field_int(map_name, obj->btf, def, m,
1155                                                &map->def.max_entries))
1156                                 return -EINVAL;
1157                         pr_debug("map '%s': found max_entries = %u.\n",
1158                                  map_name, map->def.max_entries);
1159                 } else if (strcmp(name, "map_flags") == 0) {
1160                         if (!get_map_field_int(map_name, obj->btf, def, m,
1161                                                &map->def.map_flags))
1162                                 return -EINVAL;
1163                         pr_debug("map '%s': found map_flags = %u.\n",
1164                                  map_name, map->def.map_flags);
1165                 } else if (strcmp(name, "key_size") == 0) {
1166                         __u32 sz;
1167
1168                         if (!get_map_field_int(map_name, obj->btf, def, m,
1169                                                &sz))
1170                                 return -EINVAL;
1171                         pr_debug("map '%s': found key_size = %u.\n",
1172                                  map_name, sz);
1173                         if (map->def.key_size && map->def.key_size != sz) {
1174                                 pr_warning("map '%s': conflicting key size %u != %u.\n",
1175                                            map_name, map->def.key_size, sz);
1176                                 return -EINVAL;
1177                         }
1178                         map->def.key_size = sz;
1179                 } else if (strcmp(name, "key") == 0) {
1180                         __s64 sz;
1181
1182                         t = btf__type_by_id(obj->btf, m->type);
1183                         if (!t) {
1184                                 pr_warning("map '%s': key type [%d] not found.\n",
1185                                            map_name, m->type);
1186                                 return -EINVAL;
1187                         }
1188                         if (!btf_is_ptr(t)) {
1189                                 pr_warning("map '%s': key spec is not PTR: %u.\n",
1190                                            map_name, btf_kind(t));
1191                                 return -EINVAL;
1192                         }
1193                         sz = btf__resolve_size(obj->btf, t->type);
1194                         if (sz < 0) {
1195                                 pr_warning("map '%s': can't determine key size for type [%u]: %lld.\n",
1196                                            map_name, t->type, sz);
1197                                 return sz;
1198                         }
1199                         pr_debug("map '%s': found key [%u], sz = %lld.\n",
1200                                  map_name, t->type, sz);
1201                         if (map->def.key_size && map->def.key_size != sz) {
1202                                 pr_warning("map '%s': conflicting key size %u != %lld.\n",
1203                                            map_name, map->def.key_size, sz);
1204                                 return -EINVAL;
1205                         }
1206                         map->def.key_size = sz;
1207                         map->btf_key_type_id = t->type;
1208                 } else if (strcmp(name, "value_size") == 0) {
1209                         __u32 sz;
1210
1211                         if (!get_map_field_int(map_name, obj->btf, def, m,
1212                                                &sz))
1213                                 return -EINVAL;
1214                         pr_debug("map '%s': found value_size = %u.\n",
1215                                  map_name, sz);
1216                         if (map->def.value_size && map->def.value_size != sz) {
1217                                 pr_warning("map '%s': conflicting value size %u != %u.\n",
1218                                            map_name, map->def.value_size, sz);
1219                                 return -EINVAL;
1220                         }
1221                         map->def.value_size = sz;
1222                 } else if (strcmp(name, "value") == 0) {
1223                         __s64 sz;
1224
1225                         t = btf__type_by_id(obj->btf, m->type);
1226                         if (!t) {
1227                                 pr_warning("map '%s': value type [%d] not found.\n",
1228                                            map_name, m->type);
1229                                 return -EINVAL;
1230                         }
1231                         if (!btf_is_ptr(t)) {
1232                                 pr_warning("map '%s': value spec is not PTR: %u.\n",
1233                                            map_name, btf_kind(t));
1234                                 return -EINVAL;
1235                         }
1236                         sz = btf__resolve_size(obj->btf, t->type);
1237                         if (sz < 0) {
1238                                 pr_warning("map '%s': can't determine value size for type [%u]: %lld.\n",
1239                                            map_name, t->type, sz);
1240                                 return sz;
1241                         }
1242                         pr_debug("map '%s': found value [%u], sz = %lld.\n",
1243                                  map_name, t->type, sz);
1244                         if (map->def.value_size && map->def.value_size != sz) {
1245                                 pr_warning("map '%s': conflicting value size %u != %lld.\n",
1246                                            map_name, map->def.value_size, sz);
1247                                 return -EINVAL;
1248                         }
1249                         map->def.value_size = sz;
1250                         map->btf_value_type_id = t->type;
1251                 } else {
1252                         if (strict) {
1253                                 pr_warning("map '%s': unknown field '%s'.\n",
1254                                            map_name, name);
1255                                 return -ENOTSUP;
1256                         }
1257                         pr_debug("map '%s': ignoring unknown field '%s'.\n",
1258                                  map_name, name);
1259                 }
1260         }
1261
1262         if (map->def.type == BPF_MAP_TYPE_UNSPEC) {
1263                 pr_warning("map '%s': map type isn't specified.\n", map_name);
1264                 return -EINVAL;
1265         }
1266
1267         return 0;
1268 }
1269
1270 static int bpf_object__init_user_btf_maps(struct bpf_object *obj, bool strict)
1271 {
1272         const struct btf_type *sec = NULL;
1273         int nr_types, i, vlen, err;
1274         const struct btf_type *t;
1275         const char *name;
1276         Elf_Data *data;
1277         Elf_Scn *scn;
1278
1279         if (obj->efile.btf_maps_shndx < 0)
1280                 return 0;
1281
1282         scn = elf_getscn(obj->efile.elf, obj->efile.btf_maps_shndx);
1283         if (scn)
1284                 data = elf_getdata(scn, NULL);
1285         if (!scn || !data) {
1286                 pr_warning("failed to get Elf_Data from map section %d (%s)\n",
1287                            obj->efile.maps_shndx, MAPS_ELF_SEC);
1288                 return -EINVAL;
1289         }
1290
1291         nr_types = btf__get_nr_types(obj->btf);
1292         for (i = 1; i <= nr_types; i++) {
1293                 t = btf__type_by_id(obj->btf, i);
1294                 if (!btf_is_datasec(t))
1295                         continue;
1296                 name = btf__name_by_offset(obj->btf, t->name_off);
1297                 if (strcmp(name, MAPS_ELF_SEC) == 0) {
1298                         sec = t;
1299                         break;
1300                 }
1301         }
1302
1303         if (!sec) {
1304                 pr_warning("DATASEC '%s' not found.\n", MAPS_ELF_SEC);
1305                 return -ENOENT;
1306         }
1307
1308         vlen = btf_vlen(sec);
1309         for (i = 0; i < vlen; i++) {
1310                 err = bpf_object__init_user_btf_map(obj, sec, i,
1311                                                     obj->efile.btf_maps_shndx,
1312                                                     data, strict);
1313                 if (err)
1314                         return err;
1315         }
1316
1317         return 0;
1318 }
1319
1320 static int bpf_object__init_maps(struct bpf_object *obj, int flags)
1321 {
1322         bool strict = !(flags & MAPS_RELAX_COMPAT);
1323         int err;
1324
1325         err = bpf_object__init_user_maps(obj, strict);
1326         if (err)
1327                 return err;
1328
1329         err = bpf_object__init_user_btf_maps(obj, strict);
1330         if (err)
1331                 return err;
1332
1333         err = bpf_object__init_global_data_maps(obj);
1334         if (err)
1335                 return err;
1336
1337         if (obj->nr_maps) {
1338                 qsort(obj->maps, obj->nr_maps, sizeof(obj->maps[0]),
1339                       compare_bpf_map);
1340         }
1341         return 0;
1342 }
1343
1344 static bool section_have_execinstr(struct bpf_object *obj, int idx)
1345 {
1346         Elf_Scn *scn;
1347         GElf_Shdr sh;
1348
1349         scn = elf_getscn(obj->efile.elf, idx);
1350         if (!scn)
1351                 return false;
1352
1353         if (gelf_getshdr(scn, &sh) != &sh)
1354                 return false;
1355
1356         if (sh.sh_flags & SHF_EXECINSTR)
1357                 return true;
1358
1359         return false;
1360 }
1361
1362 static void bpf_object__sanitize_btf(struct bpf_object *obj)
1363 {
1364         bool has_datasec = obj->caps.btf_datasec;
1365         bool has_func = obj->caps.btf_func;
1366         struct btf *btf = obj->btf;
1367         struct btf_type *t;
1368         int i, j, vlen;
1369
1370         if (!obj->btf || (has_func && has_datasec))
1371                 return;
1372
1373         for (i = 1; i <= btf__get_nr_types(btf); i++) {
1374                 t = (struct btf_type *)btf__type_by_id(btf, i);
1375
1376                 if (!has_datasec && btf_is_var(t)) {
1377                         /* replace VAR with INT */
1378                         t->info = BTF_INFO_ENC(BTF_KIND_INT, 0, 0);
1379                         /*
1380                          * using size = 1 is the safest choice, 4 will be too
1381                          * big and cause kernel BTF validation failure if
1382                          * original variable took less than 4 bytes
1383                          */
1384                         t->size = 1;
1385                         *(int *)(t + 1) = BTF_INT_ENC(0, 0, 8);
1386                 } else if (!has_datasec && btf_is_datasec(t)) {
1387                         /* replace DATASEC with STRUCT */
1388                         const struct btf_var_secinfo *v = btf_var_secinfos(t);
1389                         struct btf_member *m = btf_members(t);
1390                         struct btf_type *vt;
1391                         char *name;
1392
1393                         name = (char *)btf__name_by_offset(btf, t->name_off);
1394                         while (*name) {
1395                                 if (*name == '.')
1396                                         *name = '_';
1397                                 name++;
1398                         }
1399
1400                         vlen = btf_vlen(t);
1401                         t->info = BTF_INFO_ENC(BTF_KIND_STRUCT, 0, vlen);
1402                         for (j = 0; j < vlen; j++, v++, m++) {
1403                                 /* order of field assignments is important */
1404                                 m->offset = v->offset * 8;
1405                                 m->type = v->type;
1406                                 /* preserve variable name as member name */
1407                                 vt = (void *)btf__type_by_id(btf, v->type);
1408                                 m->name_off = vt->name_off;
1409                         }
1410                 } else if (!has_func && btf_is_func_proto(t)) {
1411                         /* replace FUNC_PROTO with ENUM */
1412                         vlen = btf_vlen(t);
1413                         t->info = BTF_INFO_ENC(BTF_KIND_ENUM, 0, vlen);
1414                         t->size = sizeof(__u32); /* kernel enforced */
1415                 } else if (!has_func && btf_is_func(t)) {
1416                         /* replace FUNC with TYPEDEF */
1417                         t->info = BTF_INFO_ENC(BTF_KIND_TYPEDEF, 0, 0);
1418                 }
1419         }
1420 }
1421
1422 static void bpf_object__sanitize_btf_ext(struct bpf_object *obj)
1423 {
1424         if (!obj->btf_ext)
1425                 return;
1426
1427         if (!obj->caps.btf_func) {
1428                 btf_ext__free(obj->btf_ext);
1429                 obj->btf_ext = NULL;
1430         }
1431 }
1432
1433 static bool bpf_object__is_btf_mandatory(const struct bpf_object *obj)
1434 {
1435         return obj->efile.btf_maps_shndx >= 0;
1436 }
1437
1438 static int bpf_object__init_btf(struct bpf_object *obj,
1439                                 Elf_Data *btf_data,
1440                                 Elf_Data *btf_ext_data)
1441 {
1442         bool btf_required = bpf_object__is_btf_mandatory(obj);
1443         int err = 0;
1444
1445         if (btf_data) {
1446                 obj->btf = btf__new(btf_data->d_buf, btf_data->d_size);
1447                 if (IS_ERR(obj->btf)) {
1448                         pr_warning("Error loading ELF section %s: %d.\n",
1449                                    BTF_ELF_SEC, err);
1450                         goto out;
1451                 }
1452                 err = btf__finalize_data(obj, obj->btf);
1453                 if (err) {
1454                         pr_warning("Error finalizing %s: %d.\n",
1455                                    BTF_ELF_SEC, err);
1456                         goto out;
1457                 }
1458         }
1459         if (btf_ext_data) {
1460                 if (!obj->btf) {
1461                         pr_debug("Ignore ELF section %s because its depending ELF section %s is not found.\n",
1462                                  BTF_EXT_ELF_SEC, BTF_ELF_SEC);
1463                         goto out;
1464                 }
1465                 obj->btf_ext = btf_ext__new(btf_ext_data->d_buf,
1466                                             btf_ext_data->d_size);
1467                 if (IS_ERR(obj->btf_ext)) {
1468                         pr_warning("Error loading ELF section %s: %ld. Ignored and continue.\n",
1469                                    BTF_EXT_ELF_SEC, PTR_ERR(obj->btf_ext));
1470                         obj->btf_ext = NULL;
1471                         goto out;
1472                 }
1473         }
1474 out:
1475         if (err || IS_ERR(obj->btf)) {
1476                 if (btf_required)
1477                         err = err ? : PTR_ERR(obj->btf);
1478                 else
1479                         err = 0;
1480                 if (!IS_ERR_OR_NULL(obj->btf))
1481                         btf__free(obj->btf);
1482                 obj->btf = NULL;
1483         }
1484         if (btf_required && !obj->btf) {
1485                 pr_warning("BTF is required, but is missing or corrupted.\n");
1486                 return err == 0 ? -ENOENT : err;
1487         }
1488         return 0;
1489 }
1490
1491 static int bpf_object__sanitize_and_load_btf(struct bpf_object *obj)
1492 {
1493         int err = 0;
1494
1495         if (!obj->btf)
1496                 return 0;
1497
1498         bpf_object__sanitize_btf(obj);
1499         bpf_object__sanitize_btf_ext(obj);
1500
1501         err = btf__load(obj->btf);
1502         if (err) {
1503                 pr_warning("Error loading %s into kernel: %d.\n",
1504                            BTF_ELF_SEC, err);
1505                 btf__free(obj->btf);
1506                 obj->btf = NULL;
1507                 /* btf_ext can't exist without btf, so free it as well */
1508                 if (obj->btf_ext) {
1509                         btf_ext__free(obj->btf_ext);
1510                         obj->btf_ext = NULL;
1511                 }
1512
1513                 if (bpf_object__is_btf_mandatory(obj))
1514                         return err;
1515         }
1516         return 0;
1517 }
1518
1519 static int bpf_object__elf_collect(struct bpf_object *obj, int flags)
1520 {
1521         Elf *elf = obj->efile.elf;
1522         GElf_Ehdr *ep = &obj->efile.ehdr;
1523         Elf_Data *btf_ext_data = NULL;
1524         Elf_Data *btf_data = NULL;
1525         Elf_Scn *scn = NULL;
1526         int idx = 0, err = 0;
1527
1528         /* Elf is corrupted/truncated, avoid calling elf_strptr. */
1529         if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL)) {
1530                 pr_warning("failed to get e_shstrndx from %s\n", obj->path);
1531                 return -LIBBPF_ERRNO__FORMAT;
1532         }
1533
1534         while ((scn = elf_nextscn(elf, scn)) != NULL) {
1535                 char *name;
1536                 GElf_Shdr sh;
1537                 Elf_Data *data;
1538
1539                 idx++;
1540                 if (gelf_getshdr(scn, &sh) != &sh) {
1541                         pr_warning("failed to get section(%d) header from %s\n",
1542                                    idx, obj->path);
1543                         return -LIBBPF_ERRNO__FORMAT;
1544                 }
1545
1546                 name = elf_strptr(elf, ep->e_shstrndx, sh.sh_name);
1547                 if (!name) {
1548                         pr_warning("failed to get section(%d) name from %s\n",
1549                                    idx, obj->path);
1550                         return -LIBBPF_ERRNO__FORMAT;
1551                 }
1552
1553                 data = elf_getdata(scn, 0);
1554                 if (!data) {
1555                         pr_warning("failed to get section(%d) data from %s(%s)\n",
1556                                    idx, name, obj->path);
1557                         return -LIBBPF_ERRNO__FORMAT;
1558                 }
1559                 pr_debug("section(%d) %s, size %ld, link %d, flags %lx, type=%d\n",
1560                          idx, name, (unsigned long)data->d_size,
1561                          (int)sh.sh_link, (unsigned long)sh.sh_flags,
1562                          (int)sh.sh_type);
1563
1564                 if (strcmp(name, "license") == 0) {
1565                         err = bpf_object__init_license(obj,
1566                                                        data->d_buf,
1567                                                        data->d_size);
1568                         if (err)
1569                                 return err;
1570                 } else if (strcmp(name, "version") == 0) {
1571                         err = bpf_object__init_kversion(obj,
1572                                                         data->d_buf,
1573                                                         data->d_size);
1574                         if (err)
1575                                 return err;
1576                 } else if (strcmp(name, "maps") == 0) {
1577                         obj->efile.maps_shndx = idx;
1578                 } else if (strcmp(name, MAPS_ELF_SEC) == 0) {
1579                         obj->efile.btf_maps_shndx = idx;
1580                 } else if (strcmp(name, BTF_ELF_SEC) == 0) {
1581                         btf_data = data;
1582                 } else if (strcmp(name, BTF_EXT_ELF_SEC) == 0) {
1583                         btf_ext_data = data;
1584                 } else if (sh.sh_type == SHT_SYMTAB) {
1585                         if (obj->efile.symbols) {
1586                                 pr_warning("bpf: multiple SYMTAB in %s\n",
1587                                            obj->path);
1588                                 return -LIBBPF_ERRNO__FORMAT;
1589                         }
1590                         obj->efile.symbols = data;
1591                         obj->efile.strtabidx = sh.sh_link;
1592                 } else if (sh.sh_type == SHT_PROGBITS && data->d_size > 0) {
1593                         if (sh.sh_flags & SHF_EXECINSTR) {
1594                                 if (strcmp(name, ".text") == 0)
1595                                         obj->efile.text_shndx = idx;
1596                                 err = bpf_object__add_program(obj, data->d_buf,
1597                                                               data->d_size, name, idx);
1598                                 if (err) {
1599                                         char errmsg[STRERR_BUFSIZE];
1600                                         char *cp = libbpf_strerror_r(-err, errmsg,
1601                                                                      sizeof(errmsg));
1602
1603                                         pr_warning("failed to alloc program %s (%s): %s",
1604                                                    name, obj->path, cp);
1605                                         return err;
1606                                 }
1607                         } else if (strcmp(name, ".data") == 0) {
1608                                 obj->efile.data = data;
1609                                 obj->efile.data_shndx = idx;
1610                         } else if (strcmp(name, ".rodata") == 0) {
1611                                 obj->efile.rodata = data;
1612                                 obj->efile.rodata_shndx = idx;
1613                         } else {
1614                                 pr_debug("skip section(%d) %s\n", idx, name);
1615                         }
1616                 } else if (sh.sh_type == SHT_REL) {
1617                         int nr_reloc = obj->efile.nr_reloc;
1618                         void *reloc = obj->efile.reloc;
1619                         int sec = sh.sh_info; /* points to other section */
1620
1621                         /* Only do relo for section with exec instructions */
1622                         if (!section_have_execinstr(obj, sec)) {
1623                                 pr_debug("skip relo %s(%d) for section(%d)\n",
1624                                          name, idx, sec);
1625                                 continue;
1626                         }
1627
1628                         reloc = reallocarray(reloc, nr_reloc + 1,
1629                                              sizeof(*obj->efile.reloc));
1630                         if (!reloc) {
1631                                 pr_warning("realloc failed\n");
1632                                 return -ENOMEM;
1633                         }
1634
1635                         obj->efile.reloc = reloc;
1636                         obj->efile.nr_reloc++;
1637
1638                         obj->efile.reloc[nr_reloc].shdr = sh;
1639                         obj->efile.reloc[nr_reloc].data = data;
1640                 } else if (sh.sh_type == SHT_NOBITS && strcmp(name, ".bss") == 0) {
1641                         obj->efile.bss = data;
1642                         obj->efile.bss_shndx = idx;
1643                 } else {
1644                         pr_debug("skip section(%d) %s\n", idx, name);
1645                 }
1646         }
1647
1648         if (!obj->efile.strtabidx || obj->efile.strtabidx >= idx) {
1649                 pr_warning("Corrupted ELF file: index of strtab invalid\n");
1650                 return -LIBBPF_ERRNO__FORMAT;
1651         }
1652         err = bpf_object__init_btf(obj, btf_data, btf_ext_data);
1653         if (!err)
1654                 err = bpf_object__init_maps(obj, flags);
1655         if (!err)
1656                 err = bpf_object__sanitize_and_load_btf(obj);
1657         if (!err)
1658                 err = bpf_object__init_prog_names(obj);
1659         return err;
1660 }
1661
1662 static struct bpf_program *
1663 bpf_object__find_prog_by_idx(struct bpf_object *obj, int idx)
1664 {
1665         struct bpf_program *prog;
1666         size_t i;
1667
1668         for (i = 0; i < obj->nr_programs; i++) {
1669                 prog = &obj->programs[i];
1670                 if (prog->idx == idx)
1671                         return prog;
1672         }
1673         return NULL;
1674 }
1675
1676 struct bpf_program *
1677 bpf_object__find_program_by_title(const struct bpf_object *obj,
1678                                   const char *title)
1679 {
1680         struct bpf_program *pos;
1681
1682         bpf_object__for_each_program(pos, obj) {
1683                 if (pos->section_name && !strcmp(pos->section_name, title))
1684                         return pos;
1685         }
1686         return NULL;
1687 }
1688
1689 static bool bpf_object__shndx_is_data(const struct bpf_object *obj,
1690                                       int shndx)
1691 {
1692         return shndx == obj->efile.data_shndx ||
1693                shndx == obj->efile.bss_shndx ||
1694                shndx == obj->efile.rodata_shndx;
1695 }
1696
1697 static bool bpf_object__shndx_is_maps(const struct bpf_object *obj,
1698                                       int shndx)
1699 {
1700         return shndx == obj->efile.maps_shndx ||
1701                shndx == obj->efile.btf_maps_shndx;
1702 }
1703
1704 static bool bpf_object__relo_in_known_section(const struct bpf_object *obj,
1705                                               int shndx)
1706 {
1707         return shndx == obj->efile.text_shndx ||
1708                bpf_object__shndx_is_maps(obj, shndx) ||
1709                bpf_object__shndx_is_data(obj, shndx);
1710 }
1711
1712 static enum libbpf_map_type
1713 bpf_object__section_to_libbpf_map_type(const struct bpf_object *obj, int shndx)
1714 {
1715         if (shndx == obj->efile.data_shndx)
1716                 return LIBBPF_MAP_DATA;
1717         else if (shndx == obj->efile.bss_shndx)
1718                 return LIBBPF_MAP_BSS;
1719         else if (shndx == obj->efile.rodata_shndx)
1720                 return LIBBPF_MAP_RODATA;
1721         else
1722                 return LIBBPF_MAP_UNSPEC;
1723 }
1724
1725 static int
1726 bpf_program__collect_reloc(struct bpf_program *prog, GElf_Shdr *shdr,
1727                            Elf_Data *data, struct bpf_object *obj)
1728 {
1729         Elf_Data *symbols = obj->efile.symbols;
1730         struct bpf_map *maps = obj->maps;
1731         size_t nr_maps = obj->nr_maps;
1732         int i, nrels;
1733
1734         pr_debug("collecting relocating info for: '%s'\n", prog->section_name);
1735         nrels = shdr->sh_size / shdr->sh_entsize;
1736
1737         prog->reloc_desc = malloc(sizeof(*prog->reloc_desc) * nrels);
1738         if (!prog->reloc_desc) {
1739                 pr_warning("failed to alloc memory in relocation\n");
1740                 return -ENOMEM;
1741         }
1742         prog->nr_reloc = nrels;
1743
1744         for (i = 0; i < nrels; i++) {
1745                 struct bpf_insn *insns = prog->insns;
1746                 enum libbpf_map_type type;
1747                 unsigned int insn_idx;
1748                 unsigned int shdr_idx;
1749                 const char *name;
1750                 size_t map_idx;
1751                 GElf_Sym sym;
1752                 GElf_Rel rel;
1753
1754                 if (!gelf_getrel(data, i, &rel)) {
1755                         pr_warning("relocation: failed to get %d reloc\n", i);
1756                         return -LIBBPF_ERRNO__FORMAT;
1757                 }
1758
1759                 if (!gelf_getsym(symbols, GELF_R_SYM(rel.r_info), &sym)) {
1760                         pr_warning("relocation: symbol %"PRIx64" not found\n",
1761                                    GELF_R_SYM(rel.r_info));
1762                         return -LIBBPF_ERRNO__FORMAT;
1763                 }
1764
1765                 name = elf_strptr(obj->efile.elf, obj->efile.strtabidx,
1766                                   sym.st_name) ? : "<?>";
1767
1768                 pr_debug("relo for %lld value %lld name %d (\'%s\')\n",
1769                          (long long) (rel.r_info >> 32),
1770                          (long long) sym.st_value, sym.st_name, name);
1771
1772                 shdr_idx = sym.st_shndx;
1773                 insn_idx = rel.r_offset / sizeof(struct bpf_insn);
1774                 pr_debug("relocation: insn_idx=%u, shdr_idx=%u\n",
1775                          insn_idx, shdr_idx);
1776
1777                 if (shdr_idx >= SHN_LORESERVE) {
1778                         pr_warning("relocation: not yet supported relo for non-static global \'%s\' variable in special section (0x%x) found in insns[%d].code 0x%x\n",
1779                                    name, shdr_idx, insn_idx,
1780                                    insns[insn_idx].code);
1781                         return -LIBBPF_ERRNO__RELOC;
1782                 }
1783                 if (!bpf_object__relo_in_known_section(obj, shdr_idx)) {
1784                         pr_warning("Program '%s' contains unrecognized relo data pointing to section %u\n",
1785                                    prog->section_name, shdr_idx);
1786                         return -LIBBPF_ERRNO__RELOC;
1787                 }
1788
1789                 if (insns[insn_idx].code == (BPF_JMP | BPF_CALL)) {
1790                         if (insns[insn_idx].src_reg != BPF_PSEUDO_CALL) {
1791                                 pr_warning("incorrect bpf_call opcode\n");
1792                                 return -LIBBPF_ERRNO__RELOC;
1793                         }
1794                         prog->reloc_desc[i].type = RELO_CALL;
1795                         prog->reloc_desc[i].insn_idx = insn_idx;
1796                         prog->reloc_desc[i].text_off = sym.st_value;
1797                         obj->has_pseudo_calls = true;
1798                         continue;
1799                 }
1800
1801                 if (insns[insn_idx].code != (BPF_LD | BPF_IMM | BPF_DW)) {
1802                         pr_warning("bpf: relocation: invalid relo for insns[%d].code 0x%x\n",
1803                                    insn_idx, insns[insn_idx].code);
1804                         return -LIBBPF_ERRNO__RELOC;
1805                 }
1806
1807                 if (bpf_object__shndx_is_maps(obj, shdr_idx) ||
1808                     bpf_object__shndx_is_data(obj, shdr_idx)) {
1809                         type = bpf_object__section_to_libbpf_map_type(obj, shdr_idx);
1810                         if (type != LIBBPF_MAP_UNSPEC) {
1811                                 if (GELF_ST_BIND(sym.st_info) == STB_GLOBAL) {
1812                                         pr_warning("bpf: relocation: not yet supported relo for non-static global \'%s\' variable found in insns[%d].code 0x%x\n",
1813                                                    name, insn_idx, insns[insn_idx].code);
1814                                         return -LIBBPF_ERRNO__RELOC;
1815                                 }
1816                                 if (!obj->caps.global_data) {
1817                                         pr_warning("bpf: relocation: kernel does not support global \'%s\' variable access in insns[%d]\n",
1818                                                    name, insn_idx);
1819                                         return -LIBBPF_ERRNO__RELOC;
1820                                 }
1821                         }
1822
1823                         for (map_idx = 0; map_idx < nr_maps; map_idx++) {
1824                                 if (maps[map_idx].libbpf_type != type)
1825                                         continue;
1826                                 if (type != LIBBPF_MAP_UNSPEC ||
1827                                     (maps[map_idx].sec_idx == sym.st_shndx &&
1828                                      maps[map_idx].sec_offset == sym.st_value)) {
1829                                         pr_debug("relocation: found map %zd (%s, sec_idx %d, offset %zu) for insn %u\n",
1830                                                  map_idx, maps[map_idx].name,
1831                                                  maps[map_idx].sec_idx,
1832                                                  maps[map_idx].sec_offset,
1833                                                  insn_idx);
1834                                         break;
1835                                 }
1836                         }
1837
1838                         if (map_idx >= nr_maps) {
1839                                 pr_warning("bpf relocation: map_idx %d larger than %d\n",
1840                                            (int)map_idx, (int)nr_maps - 1);
1841                                 return -LIBBPF_ERRNO__RELOC;
1842                         }
1843
1844                         prog->reloc_desc[i].type = type != LIBBPF_MAP_UNSPEC ?
1845                                                    RELO_DATA : RELO_LD64;
1846                         prog->reloc_desc[i].insn_idx = insn_idx;
1847                         prog->reloc_desc[i].map_idx = map_idx;
1848                 }
1849         }
1850         return 0;
1851 }
1852
1853 static int bpf_map_find_btf_info(struct bpf_object *obj, struct bpf_map *map)
1854 {
1855         struct bpf_map_def *def = &map->def;
1856         __u32 key_type_id = 0, value_type_id = 0;
1857         int ret;
1858
1859         /* if it's BTF-defined map, we don't need to search for type IDs */
1860         if (map->sec_idx == obj->efile.btf_maps_shndx)
1861                 return 0;
1862
1863         if (!bpf_map__is_internal(map)) {
1864                 ret = btf__get_map_kv_tids(obj->btf, map->name, def->key_size,
1865                                            def->value_size, &key_type_id,
1866                                            &value_type_id);
1867         } else {
1868                 /*
1869                  * LLVM annotates global data differently in BTF, that is,
1870                  * only as '.data', '.bss' or '.rodata'.
1871                  */
1872                 ret = btf__find_by_name(obj->btf,
1873                                 libbpf_type_to_btf_name[map->libbpf_type]);
1874         }
1875         if (ret < 0)
1876                 return ret;
1877
1878         map->btf_key_type_id = key_type_id;
1879         map->btf_value_type_id = bpf_map__is_internal(map) ?
1880                                  ret : value_type_id;
1881         return 0;
1882 }
1883
1884 int bpf_map__reuse_fd(struct bpf_map *map, int fd)
1885 {
1886         struct bpf_map_info info = {};
1887         __u32 len = sizeof(info);
1888         int new_fd, err;
1889         char *new_name;
1890
1891         err = bpf_obj_get_info_by_fd(fd, &info, &len);
1892         if (err)
1893                 return err;
1894
1895         new_name = strdup(info.name);
1896         if (!new_name)
1897                 return -errno;
1898
1899         new_fd = open("/", O_RDONLY | O_CLOEXEC);
1900         if (new_fd < 0)
1901                 goto err_free_new_name;
1902
1903         new_fd = dup3(fd, new_fd, O_CLOEXEC);
1904         if (new_fd < 0)
1905                 goto err_close_new_fd;
1906
1907         err = zclose(map->fd);
1908         if (err)
1909                 goto err_close_new_fd;
1910         free(map->name);
1911
1912         map->fd = new_fd;
1913         map->name = new_name;
1914         map->def.type = info.type;
1915         map->def.key_size = info.key_size;
1916         map->def.value_size = info.value_size;
1917         map->def.max_entries = info.max_entries;
1918         map->def.map_flags = info.map_flags;
1919         map->btf_key_type_id = info.btf_key_type_id;
1920         map->btf_value_type_id = info.btf_value_type_id;
1921
1922         return 0;
1923
1924 err_close_new_fd:
1925         close(new_fd);
1926 err_free_new_name:
1927         free(new_name);
1928         return -errno;
1929 }
1930
1931 int bpf_map__resize(struct bpf_map *map, __u32 max_entries)
1932 {
1933         if (!map || !max_entries)
1934                 return -EINVAL;
1935
1936         /* If map already created, its attributes can't be changed. */
1937         if (map->fd >= 0)
1938                 return -EBUSY;
1939
1940         map->def.max_entries = max_entries;
1941
1942         return 0;
1943 }
1944
1945 static int
1946 bpf_object__probe_name(struct bpf_object *obj)
1947 {
1948         struct bpf_load_program_attr attr;
1949         char *cp, errmsg[STRERR_BUFSIZE];
1950         struct bpf_insn insns[] = {
1951                 BPF_MOV64_IMM(BPF_REG_0, 0),
1952                 BPF_EXIT_INSN(),
1953         };
1954         int ret;
1955
1956         /* make sure basic loading works */
1957
1958         memset(&attr, 0, sizeof(attr));
1959         attr.prog_type = BPF_PROG_TYPE_SOCKET_FILTER;
1960         attr.insns = insns;
1961         attr.insns_cnt = ARRAY_SIZE(insns);
1962         attr.license = "GPL";
1963
1964         ret = bpf_load_program_xattr(&attr, NULL, 0);
1965         if (ret < 0) {
1966                 cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg));
1967                 pr_warning("Error in %s():%s(%d). Couldn't load basic 'r0 = 0' BPF program.\n",
1968                            __func__, cp, errno);
1969                 return -errno;
1970         }
1971         close(ret);
1972
1973         /* now try the same program, but with the name */
1974
1975         attr.name = "test";
1976         ret = bpf_load_program_xattr(&attr, NULL, 0);
1977         if (ret >= 0) {
1978                 obj->caps.name = 1;
1979                 close(ret);
1980         }
1981
1982         return 0;
1983 }
1984
1985 static int
1986 bpf_object__probe_global_data(struct bpf_object *obj)
1987 {
1988         struct bpf_load_program_attr prg_attr;
1989         struct bpf_create_map_attr map_attr;
1990         char *cp, errmsg[STRERR_BUFSIZE];
1991         struct bpf_insn insns[] = {
1992                 BPF_LD_MAP_VALUE(BPF_REG_1, 0, 16),
1993                 BPF_ST_MEM(BPF_DW, BPF_REG_1, 0, 42),
1994                 BPF_MOV64_IMM(BPF_REG_0, 0),
1995                 BPF_EXIT_INSN(),
1996         };
1997         int ret, map;
1998
1999         memset(&map_attr, 0, sizeof(map_attr));
2000         map_attr.map_type = BPF_MAP_TYPE_ARRAY;
2001         map_attr.key_size = sizeof(int);
2002         map_attr.value_size = 32;
2003         map_attr.max_entries = 1;
2004
2005         map = bpf_create_map_xattr(&map_attr);
2006         if (map < 0) {
2007                 cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg));
2008                 pr_warning("Error in %s():%s(%d). Couldn't create simple array map.\n",
2009                            __func__, cp, errno);
2010                 return -errno;
2011         }
2012
2013         insns[0].imm = map;
2014
2015         memset(&prg_attr, 0, sizeof(prg_attr));
2016         prg_attr.prog_type = BPF_PROG_TYPE_SOCKET_FILTER;
2017         prg_attr.insns = insns;
2018         prg_attr.insns_cnt = ARRAY_SIZE(insns);
2019         prg_attr.license = "GPL";
2020
2021         ret = bpf_load_program_xattr(&prg_attr, NULL, 0);
2022         if (ret >= 0) {
2023                 obj->caps.global_data = 1;
2024                 close(ret);
2025         }
2026
2027         close(map);
2028         return 0;
2029 }
2030
2031 static int bpf_object__probe_btf_func(struct bpf_object *obj)
2032 {
2033         const char strs[] = "\0int\0x\0a";
2034         /* void x(int a) {} */
2035         __u32 types[] = {
2036                 /* int */
2037                 BTF_TYPE_INT_ENC(1, BTF_INT_SIGNED, 0, 32, 4),  /* [1] */
2038                 /* FUNC_PROTO */                                /* [2] */
2039                 BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_FUNC_PROTO, 0, 1), 0),
2040                 BTF_PARAM_ENC(7, 1),
2041                 /* FUNC x */                                    /* [3] */
2042                 BTF_TYPE_ENC(5, BTF_INFO_ENC(BTF_KIND_FUNC, 0, 0), 2),
2043         };
2044         int btf_fd;
2045
2046         btf_fd = libbpf__load_raw_btf((char *)types, sizeof(types),
2047                                       strs, sizeof(strs));
2048         if (btf_fd >= 0) {
2049                 obj->caps.btf_func = 1;
2050                 close(btf_fd);
2051                 return 1;
2052         }
2053
2054         return 0;
2055 }
2056
2057 static int bpf_object__probe_btf_datasec(struct bpf_object *obj)
2058 {
2059         const char strs[] = "\0x\0.data";
2060         /* static int a; */
2061         __u32 types[] = {
2062                 /* int */
2063                 BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4),  /* [1] */
2064                 /* VAR x */                                     /* [2] */
2065                 BTF_TYPE_ENC(1, BTF_INFO_ENC(BTF_KIND_VAR, 0, 0), 1),
2066                 BTF_VAR_STATIC,
2067                 /* DATASEC val */                               /* [3] */
2068                 BTF_TYPE_ENC(3, BTF_INFO_ENC(BTF_KIND_DATASEC, 0, 1), 4),
2069                 BTF_VAR_SECINFO_ENC(2, 0, 4),
2070         };
2071         int btf_fd;
2072
2073         btf_fd = libbpf__load_raw_btf((char *)types, sizeof(types),
2074                                       strs, sizeof(strs));
2075         if (btf_fd >= 0) {
2076                 obj->caps.btf_datasec = 1;
2077                 close(btf_fd);
2078                 return 1;
2079         }
2080
2081         return 0;
2082 }
2083
2084 static int
2085 bpf_object__probe_caps(struct bpf_object *obj)
2086 {
2087         int (*probe_fn[])(struct bpf_object *obj) = {
2088                 bpf_object__probe_name,
2089                 bpf_object__probe_global_data,
2090                 bpf_object__probe_btf_func,
2091                 bpf_object__probe_btf_datasec,
2092         };
2093         int i, ret;
2094
2095         for (i = 0; i < ARRAY_SIZE(probe_fn); i++) {
2096                 ret = probe_fn[i](obj);
2097                 if (ret < 0)
2098                         pr_debug("Probe #%d failed with %d.\n", i, ret);
2099         }
2100
2101         return 0;
2102 }
2103
2104 static int
2105 bpf_object__populate_internal_map(struct bpf_object *obj, struct bpf_map *map)
2106 {
2107         char *cp, errmsg[STRERR_BUFSIZE];
2108         int err, zero = 0;
2109         __u8 *data;
2110
2111         /* Nothing to do here since kernel already zero-initializes .bss map. */
2112         if (map->libbpf_type == LIBBPF_MAP_BSS)
2113                 return 0;
2114
2115         data = map->libbpf_type == LIBBPF_MAP_DATA ?
2116                obj->sections.data : obj->sections.rodata;
2117
2118         err = bpf_map_update_elem(map->fd, &zero, data, 0);
2119         /* Freeze .rodata map as read-only from syscall side. */
2120         if (!err && map->libbpf_type == LIBBPF_MAP_RODATA) {
2121                 err = bpf_map_freeze(map->fd);
2122                 if (err) {
2123                         cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg));
2124                         pr_warning("Error freezing map(%s) as read-only: %s\n",
2125                                    map->name, cp);
2126                         err = 0;
2127                 }
2128         }
2129         return err;
2130 }
2131
2132 static int
2133 bpf_object__create_maps(struct bpf_object *obj)
2134 {
2135         struct bpf_create_map_attr create_attr = {};
2136         int nr_cpus = 0;
2137         unsigned int i;
2138         int err;
2139
2140         for (i = 0; i < obj->nr_maps; i++) {
2141                 struct bpf_map *map = &obj->maps[i];
2142                 struct bpf_map_def *def = &map->def;
2143                 char *cp, errmsg[STRERR_BUFSIZE];
2144                 int *pfd = &map->fd;
2145
2146                 if (map->fd >= 0) {
2147                         pr_debug("skip map create (preset) %s: fd=%d\n",
2148                                  map->name, map->fd);
2149                         continue;
2150                 }
2151
2152                 if (obj->caps.name)
2153                         create_attr.name = map->name;
2154                 create_attr.map_ifindex = map->map_ifindex;
2155                 create_attr.map_type = def->type;
2156                 create_attr.map_flags = def->map_flags;
2157                 create_attr.key_size = def->key_size;
2158                 create_attr.value_size = def->value_size;
2159                 if (def->type == BPF_MAP_TYPE_PERF_EVENT_ARRAY &&
2160                     !def->max_entries) {
2161                         if (!nr_cpus)
2162                                 nr_cpus = libbpf_num_possible_cpus();
2163                         if (nr_cpus < 0) {
2164                                 pr_warning("failed to determine number of system CPUs: %d\n",
2165                                            nr_cpus);
2166                                 err = nr_cpus;
2167                                 goto err_out;
2168                         }
2169                         pr_debug("map '%s': setting size to %d\n",
2170                                  map->name, nr_cpus);
2171                         create_attr.max_entries = nr_cpus;
2172                 } else {
2173                         create_attr.max_entries = def->max_entries;
2174                 }
2175                 create_attr.btf_fd = 0;
2176                 create_attr.btf_key_type_id = 0;
2177                 create_attr.btf_value_type_id = 0;
2178                 if (bpf_map_type__is_map_in_map(def->type) &&
2179                     map->inner_map_fd >= 0)
2180                         create_attr.inner_map_fd = map->inner_map_fd;
2181
2182                 if (obj->btf && !bpf_map_find_btf_info(obj, map)) {
2183                         create_attr.btf_fd = btf__fd(obj->btf);
2184                         create_attr.btf_key_type_id = map->btf_key_type_id;
2185                         create_attr.btf_value_type_id = map->btf_value_type_id;
2186                 }
2187
2188                 *pfd = bpf_create_map_xattr(&create_attr);
2189                 if (*pfd < 0 && (create_attr.btf_key_type_id ||
2190                                  create_attr.btf_value_type_id)) {
2191                         err = -errno;
2192                         cp = libbpf_strerror_r(err, errmsg, sizeof(errmsg));
2193                         pr_warning("Error in bpf_create_map_xattr(%s):%s(%d). Retrying without BTF.\n",
2194                                    map->name, cp, err);
2195                         create_attr.btf_fd = 0;
2196                         create_attr.btf_key_type_id = 0;
2197                         create_attr.btf_value_type_id = 0;
2198                         map->btf_key_type_id = 0;
2199                         map->btf_value_type_id = 0;
2200                         *pfd = bpf_create_map_xattr(&create_attr);
2201                 }
2202
2203                 if (*pfd < 0) {
2204                         size_t j;
2205
2206                         err = -errno;
2207 err_out:
2208                         cp = libbpf_strerror_r(err, errmsg, sizeof(errmsg));
2209                         pr_warning("failed to create map (name: '%s'): %s(%d)\n",
2210                                    map->name, cp, err);
2211                         for (j = 0; j < i; j++)
2212                                 zclose(obj->maps[j].fd);
2213                         return err;
2214                 }
2215
2216                 if (bpf_map__is_internal(map)) {
2217                         err = bpf_object__populate_internal_map(obj, map);
2218                         if (err < 0) {
2219                                 zclose(*pfd);
2220                                 goto err_out;
2221                         }
2222                 }
2223
2224                 pr_debug("created map %s: fd=%d\n", map->name, *pfd);
2225         }
2226
2227         return 0;
2228 }
2229
2230 static int
2231 check_btf_ext_reloc_err(struct bpf_program *prog, int err,
2232                         void *btf_prog_info, const char *info_name)
2233 {
2234         if (err != -ENOENT) {
2235                 pr_warning("Error in loading %s for sec %s.\n",
2236                            info_name, prog->section_name);
2237                 return err;
2238         }
2239
2240         /* err == -ENOENT (i.e. prog->section_name not found in btf_ext) */
2241
2242         if (btf_prog_info) {
2243                 /*
2244                  * Some info has already been found but has problem
2245                  * in the last btf_ext reloc. Must have to error out.
2246                  */
2247                 pr_warning("Error in relocating %s for sec %s.\n",
2248                            info_name, prog->section_name);
2249                 return err;
2250         }
2251
2252         /* Have problem loading the very first info. Ignore the rest. */
2253         pr_warning("Cannot find %s for main program sec %s. Ignore all %s.\n",
2254                    info_name, prog->section_name, info_name);
2255         return 0;
2256 }
2257
2258 static int
2259 bpf_program_reloc_btf_ext(struct bpf_program *prog, struct bpf_object *obj,
2260                           const char *section_name,  __u32 insn_offset)
2261 {
2262         int err;
2263
2264         if (!insn_offset || prog->func_info) {
2265                 /*
2266                  * !insn_offset => main program
2267                  *
2268                  * For sub prog, the main program's func_info has to
2269                  * be loaded first (i.e. prog->func_info != NULL)
2270                  */
2271                 err = btf_ext__reloc_func_info(obj->btf, obj->btf_ext,
2272                                                section_name, insn_offset,
2273                                                &prog->func_info,
2274                                                &prog->func_info_cnt);
2275                 if (err)
2276                         return check_btf_ext_reloc_err(prog, err,
2277                                                        prog->func_info,
2278                                                        "bpf_func_info");
2279
2280                 prog->func_info_rec_size = btf_ext__func_info_rec_size(obj->btf_ext);
2281         }
2282
2283         if (!insn_offset || prog->line_info) {
2284                 err = btf_ext__reloc_line_info(obj->btf, obj->btf_ext,
2285                                                section_name, insn_offset,
2286                                                &prog->line_info,
2287                                                &prog->line_info_cnt);
2288                 if (err)
2289                         return check_btf_ext_reloc_err(prog, err,
2290                                                        prog->line_info,
2291                                                        "bpf_line_info");
2292
2293                 prog->line_info_rec_size = btf_ext__line_info_rec_size(obj->btf_ext);
2294         }
2295
2296         return 0;
2297 }
2298
2299 #define BPF_CORE_SPEC_MAX_LEN 64
2300
2301 /* represents BPF CO-RE field or array element accessor */
2302 struct bpf_core_accessor {
2303         __u32 type_id;          /* struct/union type or array element type */
2304         __u32 idx;              /* field index or array index */
2305         const char *name;       /* field name or NULL for array accessor */
2306 };
2307
2308 struct bpf_core_spec {
2309         const struct btf *btf;
2310         /* high-level spec: named fields and array indices only */
2311         struct bpf_core_accessor spec[BPF_CORE_SPEC_MAX_LEN];
2312         /* high-level spec length */
2313         int len;
2314         /* raw, low-level spec: 1-to-1 with accessor spec string */
2315         int raw_spec[BPF_CORE_SPEC_MAX_LEN];
2316         /* raw spec length */
2317         int raw_len;
2318         /* field byte offset represented by spec */
2319         __u32 offset;
2320 };
2321
2322 static bool str_is_empty(const char *s)
2323 {
2324         return !s || !s[0];
2325 }
2326
2327 /*
2328  * Turn bpf_offset_reloc into a low- and high-level spec representation,
2329  * validating correctness along the way, as well as calculating resulting
2330  * field offset (in bytes), specified by accessor string. Low-level spec
2331  * captures every single level of nestedness, including traversing anonymous
2332  * struct/union members. High-level one only captures semantically meaningful
2333  * "turning points": named fields and array indicies.
2334  * E.g., for this case:
2335  *
2336  *   struct sample {
2337  *       int __unimportant;
2338  *       struct {
2339  *           int __1;
2340  *           int __2;
2341  *           int a[7];
2342  *       };
2343  *   };
2344  *
2345  *   struct sample *s = ...;
2346  *
2347  *   int x = &s->a[3]; // access string = '0:1:2:3'
2348  *
2349  * Low-level spec has 1:1 mapping with each element of access string (it's
2350  * just a parsed access string representation): [0, 1, 2, 3].
2351  *
2352  * High-level spec will capture only 3 points:
2353  *   - intial zero-index access by pointer (&s->... is the same as &s[0]...);
2354  *   - field 'a' access (corresponds to '2' in low-level spec);
2355  *   - array element #3 access (corresponds to '3' in low-level spec).
2356  *
2357  */
2358 static int bpf_core_spec_parse(const struct btf *btf,
2359                                __u32 type_id,
2360                                const char *spec_str,
2361                                struct bpf_core_spec *spec)
2362 {
2363         int access_idx, parsed_len, i;
2364         const struct btf_type *t;
2365         const char *name;
2366         __u32 id;
2367         __s64 sz;
2368
2369         if (str_is_empty(spec_str) || *spec_str == ':')
2370                 return -EINVAL;
2371
2372         memset(spec, 0, sizeof(*spec));
2373         spec->btf = btf;
2374
2375         /* parse spec_str="0:1:2:3:4" into array raw_spec=[0, 1, 2, 3, 4] */
2376         while (*spec_str) {
2377                 if (*spec_str == ':')
2378                         ++spec_str;
2379                 if (sscanf(spec_str, "%d%n", &access_idx, &parsed_len) != 1)
2380                         return -EINVAL;
2381                 if (spec->raw_len == BPF_CORE_SPEC_MAX_LEN)
2382                         return -E2BIG;
2383                 spec_str += parsed_len;
2384                 spec->raw_spec[spec->raw_len++] = access_idx;
2385         }
2386
2387         if (spec->raw_len == 0)
2388                 return -EINVAL;
2389
2390         /* first spec value is always reloc type array index */
2391         t = skip_mods_and_typedefs(btf, type_id, &id);
2392         if (!t)
2393                 return -EINVAL;
2394
2395         access_idx = spec->raw_spec[0];
2396         spec->spec[0].type_id = id;
2397         spec->spec[0].idx = access_idx;
2398         spec->len++;
2399
2400         sz = btf__resolve_size(btf, id);
2401         if (sz < 0)
2402                 return sz;
2403         spec->offset = access_idx * sz;
2404
2405         for (i = 1; i < spec->raw_len; i++) {
2406                 t = skip_mods_and_typedefs(btf, id, &id);
2407                 if (!t)
2408                         return -EINVAL;
2409
2410                 access_idx = spec->raw_spec[i];
2411
2412                 if (btf_is_composite(t)) {
2413                         const struct btf_member *m;
2414                         __u32 offset;
2415
2416                         if (access_idx >= btf_vlen(t))
2417                                 return -EINVAL;
2418                         if (btf_member_bitfield_size(t, access_idx))
2419                                 return -EINVAL;
2420
2421                         offset = btf_member_bit_offset(t, access_idx);
2422                         if (offset % 8)
2423                                 return -EINVAL;
2424                         spec->offset += offset / 8;
2425
2426                         m = btf_members(t) + access_idx;
2427                         if (m->name_off) {
2428                                 name = btf__name_by_offset(btf, m->name_off);
2429                                 if (str_is_empty(name))
2430                                         return -EINVAL;
2431
2432                                 spec->spec[spec->len].type_id = id;
2433                                 spec->spec[spec->len].idx = access_idx;
2434                                 spec->spec[spec->len].name = name;
2435                                 spec->len++;
2436                         }
2437
2438                         id = m->type;
2439                 } else if (btf_is_array(t)) {
2440                         const struct btf_array *a = btf_array(t);
2441
2442                         t = skip_mods_and_typedefs(btf, a->type, &id);
2443                         if (!t || access_idx >= a->nelems)
2444                                 return -EINVAL;
2445
2446                         spec->spec[spec->len].type_id = id;
2447                         spec->spec[spec->len].idx = access_idx;
2448                         spec->len++;
2449
2450                         sz = btf__resolve_size(btf, id);
2451                         if (sz < 0)
2452                                 return sz;
2453                         spec->offset += access_idx * sz;
2454                 } else {
2455                         pr_warning("relo for [%u] %s (at idx %d) captures type [%d] of unexpected kind %d\n",
2456                                    type_id, spec_str, i, id, btf_kind(t));
2457                         return -EINVAL;
2458                 }
2459         }
2460
2461         return 0;
2462 }
2463
2464 static bool bpf_core_is_flavor_sep(const char *s)
2465 {
2466         /* check X___Y name pattern, where X and Y are not underscores */
2467         return s[0] != '_' &&                                 /* X */
2468                s[1] == '_' && s[2] == '_' && s[3] == '_' &&   /* ___ */
2469                s[4] != '_';                                   /* Y */
2470 }
2471
2472 /* Given 'some_struct_name___with_flavor' return the length of a name prefix
2473  * before last triple underscore. Struct name part after last triple
2474  * underscore is ignored by BPF CO-RE relocation during relocation matching.
2475  */
2476 static size_t bpf_core_essential_name_len(const char *name)
2477 {
2478         size_t n = strlen(name);
2479         int i;
2480
2481         for (i = n - 5; i >= 0; i--) {
2482                 if (bpf_core_is_flavor_sep(name + i))
2483                         return i + 1;
2484         }
2485         return n;
2486 }
2487
2488 /* dynamically sized list of type IDs */
2489 struct ids_vec {
2490         __u32 *data;
2491         int len;
2492 };
2493
2494 static void bpf_core_free_cands(struct ids_vec *cand_ids)
2495 {
2496         free(cand_ids->data);
2497         free(cand_ids);
2498 }
2499
2500 static struct ids_vec *bpf_core_find_cands(const struct btf *local_btf,
2501                                            __u32 local_type_id,
2502                                            const struct btf *targ_btf)
2503 {
2504         size_t local_essent_len, targ_essent_len;
2505         const char *local_name, *targ_name;
2506         const struct btf_type *t;
2507         struct ids_vec *cand_ids;
2508         __u32 *new_ids;
2509         int i, err, n;
2510
2511         t = btf__type_by_id(local_btf, local_type_id);
2512         if (!t)
2513                 return ERR_PTR(-EINVAL);
2514
2515         local_name = btf__name_by_offset(local_btf, t->name_off);
2516         if (str_is_empty(local_name))
2517                 return ERR_PTR(-EINVAL);
2518         local_essent_len = bpf_core_essential_name_len(local_name);
2519
2520         cand_ids = calloc(1, sizeof(*cand_ids));
2521         if (!cand_ids)
2522                 return ERR_PTR(-ENOMEM);
2523
2524         n = btf__get_nr_types(targ_btf);
2525         for (i = 1; i <= n; i++) {
2526                 t = btf__type_by_id(targ_btf, i);
2527                 targ_name = btf__name_by_offset(targ_btf, t->name_off);
2528                 if (str_is_empty(targ_name))
2529                         continue;
2530
2531                 targ_essent_len = bpf_core_essential_name_len(targ_name);
2532                 if (targ_essent_len != local_essent_len)
2533                         continue;
2534
2535                 if (strncmp(local_name, targ_name, local_essent_len) == 0) {
2536                         pr_debug("[%d] %s: found candidate [%d] %s\n",
2537                                  local_type_id, local_name, i, targ_name);
2538                         new_ids = realloc(cand_ids->data, cand_ids->len + 1);
2539                         if (!new_ids) {
2540                                 err = -ENOMEM;
2541                                 goto err_out;
2542                         }
2543                         cand_ids->data = new_ids;
2544                         cand_ids->data[cand_ids->len++] = i;
2545                 }
2546         }
2547         return cand_ids;
2548 err_out:
2549         bpf_core_free_cands(cand_ids);
2550         return ERR_PTR(err);
2551 }
2552
2553 /* Check two types for compatibility, skipping const/volatile/restrict and
2554  * typedefs, to ensure we are relocating offset to the compatible entities:
2555  *   - any two STRUCTs/UNIONs are compatible and can be mixed;
2556  *   - any two FWDs are compatible;
2557  *   - any two PTRs are always compatible;
2558  *   - for ENUMs, check sizes, names are ignored;
2559  *   - for INT, size and bitness should match, signedness is ignored;
2560  *   - for ARRAY, dimensionality is ignored, element types are checked for
2561  *     compatibility recursively;
2562  *   - everything else shouldn't be ever a target of relocation.
2563  * These rules are not set in stone and probably will be adjusted as we get
2564  * more experience with using BPF CO-RE relocations.
2565  */
2566 static int bpf_core_fields_are_compat(const struct btf *local_btf,
2567                                       __u32 local_id,
2568                                       const struct btf *targ_btf,
2569                                       __u32 targ_id)
2570 {
2571         const struct btf_type *local_type, *targ_type;
2572
2573 recur:
2574         local_type = skip_mods_and_typedefs(local_btf, local_id, &local_id);
2575         targ_type = skip_mods_and_typedefs(targ_btf, targ_id, &targ_id);
2576         if (!local_type || !targ_type)
2577                 return -EINVAL;
2578
2579         if (btf_is_composite(local_type) && btf_is_composite(targ_type))
2580                 return 1;
2581         if (btf_kind(local_type) != btf_kind(targ_type))
2582                 return 0;
2583
2584         switch (btf_kind(local_type)) {
2585         case BTF_KIND_FWD:
2586         case BTF_KIND_PTR:
2587                 return 1;
2588         case BTF_KIND_ENUM:
2589                 return local_type->size == targ_type->size;
2590         case BTF_KIND_INT:
2591                 return btf_int_offset(local_type) == 0 &&
2592                        btf_int_offset(targ_type) == 0 &&
2593                        local_type->size == targ_type->size &&
2594                        btf_int_bits(local_type) == btf_int_bits(targ_type);
2595         case BTF_KIND_ARRAY:
2596                 local_id = btf_array(local_type)->type;
2597                 targ_id = btf_array(targ_type)->type;
2598                 goto recur;
2599         default:
2600                 pr_warning("unexpected kind %d relocated, local [%d], target [%d]\n",
2601                            btf_kind(local_type), local_id, targ_id);
2602                 return 0;
2603         }
2604 }
2605
2606 /*
2607  * Given single high-level named field accessor in local type, find
2608  * corresponding high-level accessor for a target type. Along the way,
2609  * maintain low-level spec for target as well. Also keep updating target
2610  * offset.
2611  *
2612  * Searching is performed through recursive exhaustive enumeration of all
2613  * fields of a struct/union. If there are any anonymous (embedded)
2614  * structs/unions, they are recursively searched as well. If field with
2615  * desired name is found, check compatibility between local and target types,
2616  * before returning result.
2617  *
2618  * 1 is returned, if field is found.
2619  * 0 is returned if no compatible field is found.
2620  * <0 is returned on error.
2621  */
2622 static int bpf_core_match_member(const struct btf *local_btf,
2623                                  const struct bpf_core_accessor *local_acc,
2624                                  const struct btf *targ_btf,
2625                                  __u32 targ_id,
2626                                  struct bpf_core_spec *spec,
2627                                  __u32 *next_targ_id)
2628 {
2629         const struct btf_type *local_type, *targ_type;
2630         const struct btf_member *local_member, *m;
2631         const char *local_name, *targ_name;
2632         __u32 local_id;
2633         int i, n, found;
2634
2635         targ_type = skip_mods_and_typedefs(targ_btf, targ_id, &targ_id);
2636         if (!targ_type)
2637                 return -EINVAL;
2638         if (!btf_is_composite(targ_type))
2639                 return 0;
2640
2641         local_id = local_acc->type_id;
2642         local_type = btf__type_by_id(local_btf, local_id);
2643         local_member = btf_members(local_type) + local_acc->idx;
2644         local_name = btf__name_by_offset(local_btf, local_member->name_off);
2645
2646         n = btf_vlen(targ_type);
2647         m = btf_members(targ_type);
2648         for (i = 0; i < n; i++, m++) {
2649                 __u32 offset;
2650
2651                 /* bitfield relocations not supported */
2652                 if (btf_member_bitfield_size(targ_type, i))
2653                         continue;
2654                 offset = btf_member_bit_offset(targ_type, i);
2655                 if (offset % 8)
2656                         continue;
2657
2658                 /* too deep struct/union/array nesting */
2659                 if (spec->raw_len == BPF_CORE_SPEC_MAX_LEN)
2660                         return -E2BIG;
2661
2662                 /* speculate this member will be the good one */
2663                 spec->offset += offset / 8;
2664                 spec->raw_spec[spec->raw_len++] = i;
2665
2666                 targ_name = btf__name_by_offset(targ_btf, m->name_off);
2667                 if (str_is_empty(targ_name)) {
2668                         /* embedded struct/union, we need to go deeper */
2669                         found = bpf_core_match_member(local_btf, local_acc,
2670                                                       targ_btf, m->type,
2671                                                       spec, next_targ_id);
2672                         if (found) /* either found or error */
2673                                 return found;
2674                 } else if (strcmp(local_name, targ_name) == 0) {
2675                         /* matching named field */
2676                         struct bpf_core_accessor *targ_acc;
2677
2678                         targ_acc = &spec->spec[spec->len++];
2679                         targ_acc->type_id = targ_id;
2680                         targ_acc->idx = i;
2681                         targ_acc->name = targ_name;
2682
2683                         *next_targ_id = m->type;
2684                         found = bpf_core_fields_are_compat(local_btf,
2685                                                            local_member->type,
2686                                                            targ_btf, m->type);
2687                         if (!found)
2688                                 spec->len--; /* pop accessor */
2689                         return found;
2690                 }
2691                 /* member turned out not to be what we looked for */
2692                 spec->offset -= offset / 8;
2693                 spec->raw_len--;
2694         }
2695
2696         return 0;
2697 }
2698
2699 /*
2700  * Try to match local spec to a target type and, if successful, produce full
2701  * target spec (high-level, low-level + offset).
2702  */
2703 static int bpf_core_spec_match(struct bpf_core_spec *local_spec,
2704                                const struct btf *targ_btf, __u32 targ_id,
2705                                struct bpf_core_spec *targ_spec)
2706 {
2707         const struct btf_type *targ_type;
2708         const struct bpf_core_accessor *local_acc;
2709         struct bpf_core_accessor *targ_acc;
2710         int i, sz, matched;
2711
2712         memset(targ_spec, 0, sizeof(*targ_spec));
2713         targ_spec->btf = targ_btf;
2714
2715         local_acc = &local_spec->spec[0];
2716         targ_acc = &targ_spec->spec[0];
2717
2718         for (i = 0; i < local_spec->len; i++, local_acc++, targ_acc++) {
2719                 targ_type = skip_mods_and_typedefs(targ_spec->btf, targ_id,
2720                                                    &targ_id);
2721                 if (!targ_type)
2722                         return -EINVAL;
2723
2724                 if (local_acc->name) {
2725                         matched = bpf_core_match_member(local_spec->btf,
2726                                                         local_acc,
2727                                                         targ_btf, targ_id,
2728                                                         targ_spec, &targ_id);
2729                         if (matched <= 0)
2730                                 return matched;
2731                 } else {
2732                         /* for i=0, targ_id is already treated as array element
2733                          * type (because it's the original struct), for others
2734                          * we should find array element type first
2735                          */
2736                         if (i > 0) {
2737                                 const struct btf_array *a;
2738
2739                                 if (!btf_is_array(targ_type))
2740                                         return 0;
2741
2742                                 a = btf_array(targ_type);
2743                                 if (local_acc->idx >= a->nelems)
2744                                         return 0;
2745                                 if (!skip_mods_and_typedefs(targ_btf, a->type,
2746                                                             &targ_id))
2747                                         return -EINVAL;
2748                         }
2749
2750                         /* too deep struct/union/array nesting */
2751                         if (targ_spec->raw_len == BPF_CORE_SPEC_MAX_LEN)
2752                                 return -E2BIG;
2753
2754                         targ_acc->type_id = targ_id;
2755                         targ_acc->idx = local_acc->idx;
2756                         targ_acc->name = NULL;
2757                         targ_spec->len++;
2758                         targ_spec->raw_spec[targ_spec->raw_len] = targ_acc->idx;
2759                         targ_spec->raw_len++;
2760
2761                         sz = btf__resolve_size(targ_btf, targ_id);
2762                         if (sz < 0)
2763                                 return sz;
2764                         targ_spec->offset += local_acc->idx * sz;
2765                 }
2766         }
2767
2768         return 1;
2769 }
2770
2771 /*
2772  * Patch relocatable BPF instruction.
2773  * Expected insn->imm value is provided for validation, as well as the new
2774  * relocated value.
2775  *
2776  * Currently three kinds of BPF instructions are supported:
2777  * 1. rX = <imm> (assignment with immediate operand);
2778  * 2. rX += <imm> (arithmetic operations with immediate operand);
2779  * 3. *(rX) = <imm> (indirect memory assignment with immediate operand).
2780  *
2781  * If actual insn->imm value is wrong, bail out.
2782  */
2783 static int bpf_core_reloc_insn(struct bpf_program *prog, int insn_off,
2784                                __u32 orig_off, __u32 new_off)
2785 {
2786         struct bpf_insn *insn;
2787         int insn_idx;
2788         __u8 class;
2789
2790         if (insn_off % sizeof(struct bpf_insn))
2791                 return -EINVAL;
2792         insn_idx = insn_off / sizeof(struct bpf_insn);
2793
2794         insn = &prog->insns[insn_idx];
2795         class = BPF_CLASS(insn->code);
2796
2797         if (class == BPF_ALU || class == BPF_ALU64) {
2798                 if (BPF_SRC(insn->code) != BPF_K)
2799                         return -EINVAL;
2800                 if (insn->imm != orig_off)
2801                         return -EINVAL;
2802                 insn->imm = new_off;
2803                 pr_debug("prog '%s': patched insn #%d (ALU/ALU64) imm %d -> %d\n",
2804                          bpf_program__title(prog, false),
2805                          insn_idx, orig_off, new_off);
2806         } else {
2807                 pr_warning("prog '%s': trying to relocate unrecognized insn #%d, code:%x, src:%x, dst:%x, off:%x, imm:%x\n",
2808                            bpf_program__title(prog, false),
2809                            insn_idx, insn->code, insn->src_reg, insn->dst_reg,
2810                            insn->off, insn->imm);
2811                 return -EINVAL;
2812         }
2813         return 0;
2814 }
2815
2816 static struct btf *btf_load_raw(const char *path)
2817 {
2818         struct btf *btf;
2819         size_t read_cnt;
2820         struct stat st;
2821         void *data;
2822         FILE *f;
2823
2824         if (stat(path, &st))
2825                 return ERR_PTR(-errno);
2826
2827         data = malloc(st.st_size);
2828         if (!data)
2829                 return ERR_PTR(-ENOMEM);
2830
2831         f = fopen(path, "rb");
2832         if (!f) {
2833                 btf = ERR_PTR(-errno);
2834                 goto cleanup;
2835         }
2836
2837         read_cnt = fread(data, 1, st.st_size, f);
2838         fclose(f);
2839         if (read_cnt < st.st_size) {
2840                 btf = ERR_PTR(-EBADF);
2841                 goto cleanup;
2842         }
2843
2844         btf = btf__new(data, read_cnt);
2845
2846 cleanup:
2847         free(data);
2848         return btf;
2849 }
2850
2851 /*
2852  * Probe few well-known locations for vmlinux kernel image and try to load BTF
2853  * data out of it to use for target BTF.
2854  */
2855 static struct btf *bpf_core_find_kernel_btf(void)
2856 {
2857         struct {
2858                 const char *path_fmt;
2859                 bool raw_btf;
2860         } locations[] = {
2861                 /* try canonical vmlinux BTF through sysfs first */
2862                 { "/sys/kernel/btf/vmlinux", true /* raw BTF */ },
2863                 /* fall back to trying to find vmlinux ELF on disk otherwise */
2864                 { "/boot/vmlinux-%1$s" },
2865                 { "/lib/modules/%1$s/vmlinux-%1$s" },
2866                 { "/lib/modules/%1$s/build/vmlinux" },
2867                 { "/usr/lib/modules/%1$s/kernel/vmlinux" },
2868                 { "/usr/lib/debug/boot/vmlinux-%1$s" },
2869                 { "/usr/lib/debug/boot/vmlinux-%1$s.debug" },
2870                 { "/usr/lib/debug/lib/modules/%1$s/vmlinux" },
2871         };
2872         char path[PATH_MAX + 1];
2873         struct utsname buf;
2874         struct btf *btf;
2875         int i;
2876
2877         uname(&buf);
2878
2879         for (i = 0; i < ARRAY_SIZE(locations); i++) {
2880                 snprintf(path, PATH_MAX, locations[i].path_fmt, buf.release);
2881
2882                 if (access(path, R_OK))
2883                         continue;
2884
2885                 if (locations[i].raw_btf)
2886                         btf = btf_load_raw(path);
2887                 else
2888                         btf = btf__parse_elf(path, NULL);
2889
2890                 pr_debug("loading kernel BTF '%s': %ld\n",
2891                          path, IS_ERR(btf) ? PTR_ERR(btf) : 0);
2892                 if (IS_ERR(btf))
2893                         continue;
2894
2895                 return btf;
2896         }
2897
2898         pr_warning("failed to find valid kernel BTF\n");
2899         return ERR_PTR(-ESRCH);
2900 }
2901
2902 /* Output spec definition in the format:
2903  * [<type-id>] (<type-name>) + <raw-spec> => <offset>@<spec>,
2904  * where <spec> is a C-syntax view of recorded field access, e.g.: x.a[3].b
2905  */
2906 static void bpf_core_dump_spec(int level, const struct bpf_core_spec *spec)
2907 {
2908         const struct btf_type *t;
2909         const char *s;
2910         __u32 type_id;
2911         int i;
2912
2913         type_id = spec->spec[0].type_id;
2914         t = btf__type_by_id(spec->btf, type_id);
2915         s = btf__name_by_offset(spec->btf, t->name_off);
2916         libbpf_print(level, "[%u] %s + ", type_id, s);
2917
2918         for (i = 0; i < spec->raw_len; i++)
2919                 libbpf_print(level, "%d%s", spec->raw_spec[i],
2920                              i == spec->raw_len - 1 ? " => " : ":");
2921
2922         libbpf_print(level, "%u @ &x", spec->offset);
2923
2924         for (i = 0; i < spec->len; i++) {
2925                 if (spec->spec[i].name)
2926                         libbpf_print(level, ".%s", spec->spec[i].name);
2927                 else
2928                         libbpf_print(level, "[%u]", spec->spec[i].idx);
2929         }
2930
2931 }
2932
2933 static size_t bpf_core_hash_fn(const void *key, void *ctx)
2934 {
2935         return (size_t)key;
2936 }
2937
2938 static bool bpf_core_equal_fn(const void *k1, const void *k2, void *ctx)
2939 {
2940         return k1 == k2;
2941 }
2942
2943 static void *u32_as_hash_key(__u32 x)
2944 {
2945         return (void *)(uintptr_t)x;
2946 }
2947
2948 /*
2949  * CO-RE relocate single instruction.
2950  *
2951  * The outline and important points of the algorithm:
2952  * 1. For given local type, find corresponding candidate target types.
2953  *    Candidate type is a type with the same "essential" name, ignoring
2954  *    everything after last triple underscore (___). E.g., `sample`,
2955  *    `sample___flavor_one`, `sample___flavor_another_one`, are all candidates
2956  *    for each other. Names with triple underscore are referred to as
2957  *    "flavors" and are useful, among other things, to allow to
2958  *    specify/support incompatible variations of the same kernel struct, which
2959  *    might differ between different kernel versions and/or build
2960  *    configurations.
2961  *
2962  *    N.B. Struct "flavors" could be generated by bpftool's BTF-to-C
2963  *    converter, when deduplicated BTF of a kernel still contains more than
2964  *    one different types with the same name. In that case, ___2, ___3, etc
2965  *    are appended starting from second name conflict. But start flavors are
2966  *    also useful to be defined "locally", in BPF program, to extract same
2967  *    data from incompatible changes between different kernel
2968  *    versions/configurations. For instance, to handle field renames between
2969  *    kernel versions, one can use two flavors of the struct name with the
2970  *    same common name and use conditional relocations to extract that field,
2971  *    depending on target kernel version.
2972  * 2. For each candidate type, try to match local specification to this
2973  *    candidate target type. Matching involves finding corresponding
2974  *    high-level spec accessors, meaning that all named fields should match,
2975  *    as well as all array accesses should be within the actual bounds. Also,
2976  *    types should be compatible (see bpf_core_fields_are_compat for details).
2977  * 3. It is supported and expected that there might be multiple flavors
2978  *    matching the spec. As long as all the specs resolve to the same set of
2979  *    offsets across all candidates, there is not error. If there is any
2980  *    ambiguity, CO-RE relocation will fail. This is necessary to accomodate
2981  *    imprefection of BTF deduplication, which can cause slight duplication of
2982  *    the same BTF type, if some directly or indirectly referenced (by
2983  *    pointer) type gets resolved to different actual types in different
2984  *    object files. If such situation occurs, deduplicated BTF will end up
2985  *    with two (or more) structurally identical types, which differ only in
2986  *    types they refer to through pointer. This should be OK in most cases and
2987  *    is not an error.
2988  * 4. Candidate types search is performed by linearly scanning through all
2989  *    types in target BTF. It is anticipated that this is overall more
2990  *    efficient memory-wise and not significantly worse (if not better)
2991  *    CPU-wise compared to prebuilding a map from all local type names to
2992  *    a list of candidate type names. It's also sped up by caching resolved
2993  *    list of matching candidates per each local "root" type ID, that has at
2994  *    least one bpf_offset_reloc associated with it. This list is shared
2995  *    between multiple relocations for the same type ID and is updated as some
2996  *    of the candidates are pruned due to structural incompatibility.
2997  */
2998 static int bpf_core_reloc_offset(struct bpf_program *prog,
2999                                  const struct bpf_offset_reloc *relo,
3000                                  int relo_idx,
3001                                  const struct btf *local_btf,
3002                                  const struct btf *targ_btf,
3003                                  struct hashmap *cand_cache)
3004 {
3005         const char *prog_name = bpf_program__title(prog, false);
3006         struct bpf_core_spec local_spec, cand_spec, targ_spec;
3007         const void *type_key = u32_as_hash_key(relo->type_id);
3008         const struct btf_type *local_type, *cand_type;
3009         const char *local_name, *cand_name;
3010         struct ids_vec *cand_ids;
3011         __u32 local_id, cand_id;
3012         const char *spec_str;
3013         int i, j, err;
3014
3015         local_id = relo->type_id;
3016         local_type = btf__type_by_id(local_btf, local_id);
3017         if (!local_type)
3018                 return -EINVAL;
3019
3020         local_name = btf__name_by_offset(local_btf, local_type->name_off);
3021         if (str_is_empty(local_name))
3022                 return -EINVAL;
3023
3024         spec_str = btf__name_by_offset(local_btf, relo->access_str_off);
3025         if (str_is_empty(spec_str))
3026                 return -EINVAL;
3027
3028         err = bpf_core_spec_parse(local_btf, local_id, spec_str, &local_spec);
3029         if (err) {
3030                 pr_warning("prog '%s': relo #%d: parsing [%d] %s + %s failed: %d\n",
3031                            prog_name, relo_idx, local_id, local_name, spec_str,
3032                            err);
3033                 return -EINVAL;
3034         }
3035
3036         pr_debug("prog '%s': relo #%d: spec is ", prog_name, relo_idx);
3037         bpf_core_dump_spec(LIBBPF_DEBUG, &local_spec);
3038         libbpf_print(LIBBPF_DEBUG, "\n");
3039
3040         if (!hashmap__find(cand_cache, type_key, (void **)&cand_ids)) {
3041                 cand_ids = bpf_core_find_cands(local_btf, local_id, targ_btf);
3042                 if (IS_ERR(cand_ids)) {
3043                         pr_warning("prog '%s': relo #%d: target candidate search failed for [%d] %s: %ld",
3044                                    prog_name, relo_idx, local_id, local_name,
3045                                    PTR_ERR(cand_ids));
3046                         return PTR_ERR(cand_ids);
3047                 }
3048                 err = hashmap__set(cand_cache, type_key, cand_ids, NULL, NULL);
3049                 if (err) {
3050                         bpf_core_free_cands(cand_ids);
3051                         return err;
3052                 }
3053         }
3054
3055         for (i = 0, j = 0; i < cand_ids->len; i++) {
3056                 cand_id = cand_ids->data[i];
3057                 cand_type = btf__type_by_id(targ_btf, cand_id);
3058                 cand_name = btf__name_by_offset(targ_btf, cand_type->name_off);
3059
3060                 err = bpf_core_spec_match(&local_spec, targ_btf,
3061                                           cand_id, &cand_spec);
3062                 pr_debug("prog '%s': relo #%d: matching candidate #%d %s against spec ",
3063                          prog_name, relo_idx, i, cand_name);
3064                 bpf_core_dump_spec(LIBBPF_DEBUG, &cand_spec);
3065                 libbpf_print(LIBBPF_DEBUG, ": %d\n", err);
3066                 if (err < 0) {
3067                         pr_warning("prog '%s': relo #%d: matching error: %d\n",
3068                                    prog_name, relo_idx, err);
3069                         return err;
3070                 }
3071                 if (err == 0)
3072                         continue;
3073
3074                 if (j == 0) {
3075                         targ_spec = cand_spec;
3076                 } else if (cand_spec.offset != targ_spec.offset) {
3077                         /* if there are many candidates, they should all
3078                          * resolve to the same offset
3079                          */
3080                         pr_warning("prog '%s': relo #%d: offset ambiguity: %u != %u\n",
3081                                    prog_name, relo_idx, cand_spec.offset,
3082                                    targ_spec.offset);
3083                         return -EINVAL;
3084                 }
3085
3086                 cand_ids->data[j++] = cand_spec.spec[0].type_id;
3087         }
3088
3089         cand_ids->len = j;
3090         if (cand_ids->len == 0) {
3091                 pr_warning("prog '%s': relo #%d: no matching targets found for [%d] %s + %s\n",
3092                            prog_name, relo_idx, local_id, local_name, spec_str);
3093                 return -ESRCH;
3094         }
3095
3096         err = bpf_core_reloc_insn(prog, relo->insn_off,
3097                                   local_spec.offset, targ_spec.offset);
3098         if (err) {
3099                 pr_warning("prog '%s': relo #%d: failed to patch insn at offset %d: %d\n",
3100                            prog_name, relo_idx, relo->insn_off, err);
3101                 return -EINVAL;
3102         }
3103
3104         return 0;
3105 }
3106
3107 static int
3108 bpf_core_reloc_offsets(struct bpf_object *obj, const char *targ_btf_path)
3109 {
3110         const struct btf_ext_info_sec *sec;
3111         const struct bpf_offset_reloc *rec;
3112         const struct btf_ext_info *seg;
3113         struct hashmap_entry *entry;
3114         struct hashmap *cand_cache = NULL;
3115         struct bpf_program *prog;
3116         struct btf *targ_btf;
3117         const char *sec_name;
3118         int i, err = 0;
3119
3120         if (targ_btf_path)
3121                 targ_btf = btf__parse_elf(targ_btf_path, NULL);
3122         else
3123                 targ_btf = bpf_core_find_kernel_btf();
3124         if (IS_ERR(targ_btf)) {
3125                 pr_warning("failed to get target BTF: %ld\n",
3126                            PTR_ERR(targ_btf));
3127                 return PTR_ERR(targ_btf);
3128         }
3129
3130         cand_cache = hashmap__new(bpf_core_hash_fn, bpf_core_equal_fn, NULL);
3131         if (IS_ERR(cand_cache)) {
3132                 err = PTR_ERR(cand_cache);
3133                 goto out;
3134         }
3135
3136         seg = &obj->btf_ext->offset_reloc_info;
3137         for_each_btf_ext_sec(seg, sec) {
3138                 sec_name = btf__name_by_offset(obj->btf, sec->sec_name_off);
3139                 if (str_is_empty(sec_name)) {
3140                         err = -EINVAL;
3141                         goto out;
3142                 }
3143                 prog = bpf_object__find_program_by_title(obj, sec_name);
3144                 if (!prog) {
3145                         pr_warning("failed to find program '%s' for CO-RE offset relocation\n",
3146                                    sec_name);
3147                         err = -EINVAL;
3148                         goto out;
3149                 }
3150
3151                 pr_debug("prog '%s': performing %d CO-RE offset relocs\n",
3152                          sec_name, sec->num_info);
3153
3154                 for_each_btf_ext_rec(seg, sec, i, rec) {
3155                         err = bpf_core_reloc_offset(prog, rec, i, obj->btf,
3156                                                     targ_btf, cand_cache);
3157                         if (err) {
3158                                 pr_warning("prog '%s': relo #%d: failed to relocate: %d\n",
3159                                            sec_name, i, err);
3160                                 goto out;
3161                         }
3162                 }
3163         }
3164
3165 out:
3166         btf__free(targ_btf);
3167         if (!IS_ERR_OR_NULL(cand_cache)) {
3168                 hashmap__for_each_entry(cand_cache, entry, i) {
3169                         bpf_core_free_cands(entry->value);
3170                 }
3171                 hashmap__free(cand_cache);
3172         }
3173         return err;
3174 }
3175
3176 static int
3177 bpf_object__relocate_core(struct bpf_object *obj, const char *targ_btf_path)
3178 {
3179         int err = 0;
3180
3181         if (obj->btf_ext->offset_reloc_info.len)
3182                 err = bpf_core_reloc_offsets(obj, targ_btf_path);
3183
3184         return err;
3185 }
3186
3187 static int
3188 bpf_program__reloc_text(struct bpf_program *prog, struct bpf_object *obj,
3189                         struct reloc_desc *relo)
3190 {
3191         struct bpf_insn *insn, *new_insn;
3192         struct bpf_program *text;
3193         size_t new_cnt;
3194         int err;
3195
3196         if (relo->type != RELO_CALL)
3197                 return -LIBBPF_ERRNO__RELOC;
3198
3199         if (prog->idx == obj->efile.text_shndx) {
3200                 pr_warning("relo in .text insn %d into off %d\n",
3201                            relo->insn_idx, relo->text_off);
3202                 return -LIBBPF_ERRNO__RELOC;
3203         }
3204
3205         if (prog->main_prog_cnt == 0) {
3206                 text = bpf_object__find_prog_by_idx(obj, obj->efile.text_shndx);
3207                 if (!text) {
3208                         pr_warning("no .text section found yet relo into text exist\n");
3209                         return -LIBBPF_ERRNO__RELOC;
3210                 }
3211                 new_cnt = prog->insns_cnt + text->insns_cnt;
3212                 new_insn = reallocarray(prog->insns, new_cnt, sizeof(*insn));
3213                 if (!new_insn) {
3214                         pr_warning("oom in prog realloc\n");
3215                         return -ENOMEM;
3216                 }
3217
3218                 if (obj->btf_ext) {
3219                         err = bpf_program_reloc_btf_ext(prog, obj,
3220                                                         text->section_name,
3221                                                         prog->insns_cnt);
3222                         if (err)
3223                                 return err;
3224                 }
3225
3226                 memcpy(new_insn + prog->insns_cnt, text->insns,
3227                        text->insns_cnt * sizeof(*insn));
3228                 prog->insns = new_insn;
3229                 prog->main_prog_cnt = prog->insns_cnt;
3230                 prog->insns_cnt = new_cnt;
3231                 pr_debug("added %zd insn from %s to prog %s\n",
3232                          text->insns_cnt, text->section_name,
3233                          prog->section_name);
3234         }
3235         insn = &prog->insns[relo->insn_idx];
3236         insn->imm += prog->main_prog_cnt - relo->insn_idx;
3237         return 0;
3238 }
3239
3240 static int
3241 bpf_program__relocate(struct bpf_program *prog, struct bpf_object *obj)
3242 {
3243         int i, err;
3244
3245         if (!prog)
3246                 return 0;
3247
3248         if (obj->btf_ext) {
3249                 err = bpf_program_reloc_btf_ext(prog, obj,
3250                                                 prog->section_name, 0);
3251                 if (err)
3252                         return err;
3253         }
3254
3255         if (!prog->reloc_desc)
3256                 return 0;
3257
3258         for (i = 0; i < prog->nr_reloc; i++) {
3259                 if (prog->reloc_desc[i].type == RELO_LD64 ||
3260                     prog->reloc_desc[i].type == RELO_DATA) {
3261                         bool relo_data = prog->reloc_desc[i].type == RELO_DATA;
3262                         struct bpf_insn *insns = prog->insns;
3263                         int insn_idx, map_idx;
3264
3265                         insn_idx = prog->reloc_desc[i].insn_idx;
3266                         map_idx = prog->reloc_desc[i].map_idx;
3267
3268                         if (insn_idx + 1 >= (int)prog->insns_cnt) {
3269                                 pr_warning("relocation out of range: '%s'\n",
3270                                            prog->section_name);
3271                                 return -LIBBPF_ERRNO__RELOC;
3272                         }
3273
3274                         if (!relo_data) {
3275                                 insns[insn_idx].src_reg = BPF_PSEUDO_MAP_FD;
3276                         } else {
3277                                 insns[insn_idx].src_reg = BPF_PSEUDO_MAP_VALUE;
3278                                 insns[insn_idx + 1].imm = insns[insn_idx].imm;
3279                         }
3280                         insns[insn_idx].imm = obj->maps[map_idx].fd;
3281                 } else if (prog->reloc_desc[i].type == RELO_CALL) {
3282                         err = bpf_program__reloc_text(prog, obj,
3283                                                       &prog->reloc_desc[i]);
3284                         if (err)
3285                                 return err;
3286                 }
3287         }
3288
3289         zfree(&prog->reloc_desc);
3290         prog->nr_reloc = 0;
3291         return 0;
3292 }
3293
3294 static int
3295 bpf_object__relocate(struct bpf_object *obj, const char *targ_btf_path)
3296 {
3297         struct bpf_program *prog;
3298         size_t i;
3299         int err;
3300
3301         if (obj->btf_ext) {
3302                 err = bpf_object__relocate_core(obj, targ_btf_path);
3303                 if (err) {
3304                         pr_warning("failed to perform CO-RE relocations: %d\n",
3305                                    err);
3306                         return err;
3307                 }
3308         }
3309         for (i = 0; i < obj->nr_programs; i++) {
3310                 prog = &obj->programs[i];
3311
3312                 err = bpf_program__relocate(prog, obj);
3313                 if (err) {
3314                         pr_warning("failed to relocate '%s'\n",
3315                                    prog->section_name);
3316                         return err;
3317                 }
3318         }
3319         return 0;
3320 }
3321
3322 static int bpf_object__collect_reloc(struct bpf_object *obj)
3323 {
3324         int i, err;
3325
3326         if (!obj_elf_valid(obj)) {
3327                 pr_warning("Internal error: elf object is closed\n");
3328                 return -LIBBPF_ERRNO__INTERNAL;
3329         }
3330
3331         for (i = 0; i < obj->efile.nr_reloc; i++) {
3332                 GElf_Shdr *shdr = &obj->efile.reloc[i].shdr;
3333                 Elf_Data *data = obj->efile.reloc[i].data;
3334                 int idx = shdr->sh_info;
3335                 struct bpf_program *prog;
3336
3337                 if (shdr->sh_type != SHT_REL) {
3338                         pr_warning("internal error at %d\n", __LINE__);
3339                         return -LIBBPF_ERRNO__INTERNAL;
3340                 }
3341
3342                 prog = bpf_object__find_prog_by_idx(obj, idx);
3343                 if (!prog) {
3344                         pr_warning("relocation failed: no section(%d)\n", idx);
3345                         return -LIBBPF_ERRNO__RELOC;
3346                 }
3347
3348                 err = bpf_program__collect_reloc(prog, shdr, data, obj);
3349                 if (err)
3350                         return err;
3351         }
3352         return 0;
3353 }
3354
3355 static int
3356 load_program(struct bpf_program *prog, struct bpf_insn *insns, int insns_cnt,
3357              char *license, __u32 kern_version, int *pfd)
3358 {
3359         struct bpf_load_program_attr load_attr;
3360         char *cp, errmsg[STRERR_BUFSIZE];
3361         int log_buf_size = BPF_LOG_BUF_SIZE;
3362         char *log_buf;
3363         int btf_fd, ret;
3364
3365         if (!insns || !insns_cnt)
3366                 return -EINVAL;
3367
3368         memset(&load_attr, 0, sizeof(struct bpf_load_program_attr));
3369         load_attr.prog_type = prog->type;
3370         load_attr.expected_attach_type = prog->expected_attach_type;
3371         if (prog->caps->name)
3372                 load_attr.name = prog->name;
3373         load_attr.insns = insns;
3374         load_attr.insns_cnt = insns_cnt;
3375         load_attr.license = license;
3376         load_attr.kern_version = kern_version;
3377         load_attr.prog_ifindex = prog->prog_ifindex;
3378         /* if .BTF.ext was loaded, kernel supports associated BTF for prog */
3379         if (prog->obj->btf_ext)
3380                 btf_fd = bpf_object__btf_fd(prog->obj);
3381         else
3382                 btf_fd = -1;
3383         load_attr.prog_btf_fd = btf_fd >= 0 ? btf_fd : 0;
3384         load_attr.func_info = prog->func_info;
3385         load_attr.func_info_rec_size = prog->func_info_rec_size;
3386         load_attr.func_info_cnt = prog->func_info_cnt;
3387         load_attr.line_info = prog->line_info;
3388         load_attr.line_info_rec_size = prog->line_info_rec_size;
3389         load_attr.line_info_cnt = prog->line_info_cnt;
3390         load_attr.log_level = prog->log_level;
3391         load_attr.prog_flags = prog->prog_flags;
3392
3393 retry_load:
3394         log_buf = malloc(log_buf_size);
3395         if (!log_buf)
3396                 pr_warning("Alloc log buffer for bpf loader error, continue without log\n");
3397
3398         ret = bpf_load_program_xattr(&load_attr, log_buf, log_buf_size);
3399
3400         if (ret >= 0) {
3401                 if (load_attr.log_level)
3402                         pr_debug("verifier log:\n%s", log_buf);
3403                 *pfd = ret;
3404                 ret = 0;
3405                 goto out;
3406         }
3407
3408         if (errno == ENOSPC) {
3409                 log_buf_size <<= 1;
3410                 free(log_buf);
3411                 goto retry_load;
3412         }
3413         ret = -LIBBPF_ERRNO__LOAD;
3414         cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg));
3415         pr_warning("load bpf program failed: %s\n", cp);
3416
3417         if (log_buf && log_buf[0] != '\0') {
3418                 ret = -LIBBPF_ERRNO__VERIFY;
3419                 pr_warning("-- BEGIN DUMP LOG ---\n");
3420                 pr_warning("\n%s\n", log_buf);
3421                 pr_warning("-- END LOG --\n");
3422         } else if (load_attr.insns_cnt >= BPF_MAXINSNS) {
3423                 pr_warning("Program too large (%zu insns), at most %d insns\n",
3424                            load_attr.insns_cnt, BPF_MAXINSNS);
3425                 ret = -LIBBPF_ERRNO__PROG2BIG;
3426         } else {
3427                 /* Wrong program type? */
3428                 if (load_attr.prog_type != BPF_PROG_TYPE_KPROBE) {
3429                         int fd;
3430
3431                         load_attr.prog_type = BPF_PROG_TYPE_KPROBE;
3432                         load_attr.expected_attach_type = 0;
3433                         fd = bpf_load_program_xattr(&load_attr, NULL, 0);
3434                         if (fd >= 0) {
3435                                 close(fd);
3436                                 ret = -LIBBPF_ERRNO__PROGTYPE;
3437                                 goto out;
3438                         }
3439                 }
3440
3441                 if (log_buf)
3442                         ret = -LIBBPF_ERRNO__KVER;
3443         }
3444
3445 out:
3446         free(log_buf);
3447         return ret;
3448 }
3449
3450 int
3451 bpf_program__load(struct bpf_program *prog,
3452                   char *license, __u32 kern_version)
3453 {
3454         int err = 0, fd, i;
3455
3456         if (prog->instances.nr < 0 || !prog->instances.fds) {
3457                 if (prog->preprocessor) {
3458                         pr_warning("Internal error: can't load program '%s'\n",
3459                                    prog->section_name);
3460                         return -LIBBPF_ERRNO__INTERNAL;
3461                 }
3462
3463                 prog->instances.fds = malloc(sizeof(int));
3464                 if (!prog->instances.fds) {
3465                         pr_warning("Not enough memory for BPF fds\n");
3466                         return -ENOMEM;
3467                 }
3468                 prog->instances.nr = 1;
3469                 prog->instances.fds[0] = -1;
3470         }
3471
3472         if (!prog->preprocessor) {
3473                 if (prog->instances.nr != 1) {
3474                         pr_warning("Program '%s' is inconsistent: nr(%d) != 1\n",
3475                                    prog->section_name, prog->instances.nr);
3476                 }
3477                 err = load_program(prog, prog->insns, prog->insns_cnt,
3478                                    license, kern_version, &fd);
3479                 if (!err)
3480                         prog->instances.fds[0] = fd;
3481                 goto out;
3482         }
3483
3484         for (i = 0; i < prog->instances.nr; i++) {
3485                 struct bpf_prog_prep_result result;
3486                 bpf_program_prep_t preprocessor = prog->preprocessor;
3487
3488                 memset(&result, 0, sizeof(result));
3489                 err = preprocessor(prog, i, prog->insns,
3490                                    prog->insns_cnt, &result);
3491                 if (err) {
3492                         pr_warning("Preprocessing the %dth instance of program '%s' failed\n",
3493                                    i, prog->section_name);
3494                         goto out;
3495                 }
3496
3497                 if (!result.new_insn_ptr || !result.new_insn_cnt) {
3498                         pr_debug("Skip loading the %dth instance of program '%s'\n",
3499                                  i, prog->section_name);
3500                         prog->instances.fds[i] = -1;
3501                         if (result.pfd)
3502                                 *result.pfd = -1;
3503                         continue;
3504                 }
3505
3506                 err = load_program(prog, result.new_insn_ptr,
3507                                    result.new_insn_cnt,
3508                                    license, kern_version, &fd);
3509
3510                 if (err) {
3511                         pr_warning("Loading the %dth instance of program '%s' failed\n",
3512                                         i, prog->section_name);
3513                         goto out;
3514                 }
3515
3516                 if (result.pfd)
3517                         *result.pfd = fd;
3518                 prog->instances.fds[i] = fd;
3519         }
3520 out:
3521         if (err)
3522                 pr_warning("failed to load program '%s'\n",
3523                            prog->section_name);
3524         zfree(&prog->insns);
3525         prog->insns_cnt = 0;
3526         return err;
3527 }
3528
3529 static bool bpf_program__is_function_storage(const struct bpf_program *prog,
3530                                              const struct bpf_object *obj)
3531 {
3532         return prog->idx == obj->efile.text_shndx && obj->has_pseudo_calls;
3533 }
3534
3535 static int
3536 bpf_object__load_progs(struct bpf_object *obj, int log_level)
3537 {
3538         size_t i;
3539         int err;
3540
3541         for (i = 0; i < obj->nr_programs; i++) {
3542                 if (bpf_program__is_function_storage(&obj->programs[i], obj))
3543                         continue;
3544                 obj->programs[i].log_level |= log_level;
3545                 err = bpf_program__load(&obj->programs[i],
3546                                         obj->license,
3547                                         obj->kern_version);
3548                 if (err)
3549                         return err;
3550         }
3551         return 0;
3552 }
3553
3554 static bool bpf_prog_type__needs_kver(enum bpf_prog_type type)
3555 {
3556         switch (type) {
3557         case BPF_PROG_TYPE_SOCKET_FILTER:
3558         case BPF_PROG_TYPE_SCHED_CLS:
3559         case BPF_PROG_TYPE_SCHED_ACT:
3560         case BPF_PROG_TYPE_XDP:
3561         case BPF_PROG_TYPE_CGROUP_SKB:
3562         case BPF_PROG_TYPE_CGROUP_SOCK:
3563         case BPF_PROG_TYPE_LWT_IN:
3564         case BPF_PROG_TYPE_LWT_OUT:
3565         case BPF_PROG_TYPE_LWT_XMIT:
3566         case BPF_PROG_TYPE_LWT_SEG6LOCAL:
3567         case BPF_PROG_TYPE_SOCK_OPS:
3568         case BPF_PROG_TYPE_SK_SKB:
3569         case BPF_PROG_TYPE_CGROUP_DEVICE:
3570         case BPF_PROG_TYPE_SK_MSG:
3571         case BPF_PROG_TYPE_CGROUP_SOCK_ADDR:
3572         case BPF_PROG_TYPE_LIRC_MODE2:
3573         case BPF_PROG_TYPE_SK_REUSEPORT:
3574         case BPF_PROG_TYPE_FLOW_DISSECTOR:
3575         case BPF_PROG_TYPE_UNSPEC:
3576         case BPF_PROG_TYPE_TRACEPOINT:
3577         case BPF_PROG_TYPE_RAW_TRACEPOINT:
3578         case BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE:
3579         case BPF_PROG_TYPE_PERF_EVENT:
3580         case BPF_PROG_TYPE_CGROUP_SYSCTL:
3581         case BPF_PROG_TYPE_CGROUP_SOCKOPT:
3582                 return false;
3583         case BPF_PROG_TYPE_KPROBE:
3584         default:
3585                 return true;
3586         }
3587 }
3588
3589 static int bpf_object__validate(struct bpf_object *obj, bool needs_kver)
3590 {
3591         if (needs_kver && obj->kern_version == 0) {
3592                 pr_warning("%s doesn't provide kernel version\n",
3593                            obj->path);
3594                 return -LIBBPF_ERRNO__KVERSION;
3595         }
3596         return 0;
3597 }
3598
3599 static struct bpf_object *
3600 __bpf_object__open(const char *path, void *obj_buf, size_t obj_buf_sz,
3601                    bool needs_kver, int flags)
3602 {
3603         struct bpf_object *obj;
3604         int err;
3605
3606         if (elf_version(EV_CURRENT) == EV_NONE) {
3607                 pr_warning("failed to init libelf for %s\n", path);
3608                 return ERR_PTR(-LIBBPF_ERRNO__LIBELF);
3609         }
3610
3611         obj = bpf_object__new(path, obj_buf, obj_buf_sz);
3612         if (IS_ERR(obj))
3613                 return obj;
3614
3615         CHECK_ERR(bpf_object__elf_init(obj), err, out);
3616         CHECK_ERR(bpf_object__check_endianness(obj), err, out);
3617         CHECK_ERR(bpf_object__probe_caps(obj), err, out);
3618         CHECK_ERR(bpf_object__elf_collect(obj, flags), err, out);
3619         CHECK_ERR(bpf_object__collect_reloc(obj), err, out);
3620         CHECK_ERR(bpf_object__validate(obj, needs_kver), err, out);
3621
3622         bpf_object__elf_finish(obj);
3623         return obj;
3624 out:
3625         bpf_object__close(obj);
3626         return ERR_PTR(err);
3627 }
3628
3629 struct bpf_object *__bpf_object__open_xattr(struct bpf_object_open_attr *attr,
3630                                             int flags)
3631 {
3632         /* param validation */
3633         if (!attr->file)
3634                 return NULL;
3635
3636         pr_debug("loading %s\n", attr->file);
3637
3638         return __bpf_object__open(attr->file, NULL, 0,
3639                                   bpf_prog_type__needs_kver(attr->prog_type),
3640                                   flags);
3641 }
3642
3643 struct bpf_object *bpf_object__open_xattr(struct bpf_object_open_attr *attr)
3644 {
3645         return __bpf_object__open_xattr(attr, 0);
3646 }
3647
3648 struct bpf_object *bpf_object__open(const char *path)
3649 {
3650         struct bpf_object_open_attr attr = {
3651                 .file           = path,
3652                 .prog_type      = BPF_PROG_TYPE_UNSPEC,
3653         };
3654
3655         return bpf_object__open_xattr(&attr);
3656 }
3657
3658 struct bpf_object *bpf_object__open_buffer(void *obj_buf,
3659                                            size_t obj_buf_sz,
3660                                            const char *name)
3661 {
3662         char tmp_name[64];
3663
3664         /* param validation */
3665         if (!obj_buf || obj_buf_sz <= 0)
3666                 return NULL;
3667
3668         if (!name) {
3669                 snprintf(tmp_name, sizeof(tmp_name), "%lx-%lx",
3670                          (unsigned long)obj_buf,
3671                          (unsigned long)obj_buf_sz);
3672                 name = tmp_name;
3673         }
3674         pr_debug("loading object '%s' from buffer\n", name);
3675
3676         return __bpf_object__open(name, obj_buf, obj_buf_sz, true, true);
3677 }
3678
3679 int bpf_object__unload(struct bpf_object *obj)
3680 {
3681         size_t i;
3682
3683         if (!obj)
3684                 return -EINVAL;
3685
3686         for (i = 0; i < obj->nr_maps; i++)
3687                 zclose(obj->maps[i].fd);
3688
3689         for (i = 0; i < obj->nr_programs; i++)
3690                 bpf_program__unload(&obj->programs[i]);
3691
3692         return 0;
3693 }
3694
3695 int bpf_object__load_xattr(struct bpf_object_load_attr *attr)
3696 {
3697         struct bpf_object *obj;
3698         int err;
3699
3700         if (!attr)
3701                 return -EINVAL;
3702         obj = attr->obj;
3703         if (!obj)
3704                 return -EINVAL;
3705
3706         if (obj->loaded) {
3707                 pr_warning("object should not be loaded twice\n");
3708                 return -EINVAL;
3709         }
3710
3711         obj->loaded = true;
3712
3713         CHECK_ERR(bpf_object__create_maps(obj), err, out);
3714         CHECK_ERR(bpf_object__relocate(obj, attr->target_btf_path), err, out);
3715         CHECK_ERR(bpf_object__load_progs(obj, attr->log_level), err, out);
3716
3717         return 0;
3718 out:
3719         bpf_object__unload(obj);
3720         pr_warning("failed to load object '%s'\n", obj->path);
3721         return err;
3722 }
3723
3724 int bpf_object__load(struct bpf_object *obj)
3725 {
3726         struct bpf_object_load_attr attr = {
3727                 .obj = obj,
3728         };
3729
3730         return bpf_object__load_xattr(&attr);
3731 }
3732
3733 static int check_path(const char *path)
3734 {
3735         char *cp, errmsg[STRERR_BUFSIZE];
3736         struct statfs st_fs;
3737         char *dname, *dir;
3738         int err = 0;
3739
3740         if (path == NULL)
3741                 return -EINVAL;
3742
3743         dname = strdup(path);
3744         if (dname == NULL)
3745                 return -ENOMEM;
3746
3747         dir = dirname(dname);
3748         if (statfs(dir, &st_fs)) {
3749                 cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg));
3750                 pr_warning("failed to statfs %s: %s\n", dir, cp);
3751                 err = -errno;
3752         }
3753         free(dname);
3754
3755         if (!err && st_fs.f_type != BPF_FS_MAGIC) {
3756                 pr_warning("specified path %s is not on BPF FS\n", path);
3757                 err = -EINVAL;
3758         }
3759
3760         return err;
3761 }
3762
3763 int bpf_program__pin_instance(struct bpf_program *prog, const char *path,
3764                               int instance)
3765 {
3766         char *cp, errmsg[STRERR_BUFSIZE];
3767         int err;
3768
3769         err = check_path(path);
3770         if (err)
3771                 return err;
3772
3773         if (prog == NULL) {
3774                 pr_warning("invalid program pointer\n");
3775                 return -EINVAL;
3776         }
3777
3778         if (instance < 0 || instance >= prog->instances.nr) {
3779                 pr_warning("invalid prog instance %d of prog %s (max %d)\n",
3780                            instance, prog->section_name, prog->instances.nr);
3781                 return -EINVAL;
3782         }
3783
3784         if (bpf_obj_pin(prog->instances.fds[instance], path)) {
3785                 cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg));
3786                 pr_warning("failed to pin program: %s\n", cp);
3787                 return -errno;
3788         }
3789         pr_debug("pinned program '%s'\n", path);
3790
3791         return 0;
3792 }
3793
3794 int bpf_program__unpin_instance(struct bpf_program *prog, const char *path,
3795                                 int instance)
3796 {
3797         int err;
3798
3799         err = check_path(path);
3800         if (err)
3801                 return err;
3802
3803         if (prog == NULL) {
3804                 pr_warning("invalid program pointer\n");
3805                 return -EINVAL;
3806         }
3807
3808         if (instance < 0 || instance >= prog->instances.nr) {
3809                 pr_warning("invalid prog instance %d of prog %s (max %d)\n",
3810                            instance, prog->section_name, prog->instances.nr);
3811                 return -EINVAL;
3812         }
3813
3814         err = unlink(path);
3815         if (err != 0)
3816                 return -errno;
3817         pr_debug("unpinned program '%s'\n", path);
3818
3819         return 0;
3820 }
3821
3822 static int make_dir(const char *path)
3823 {
3824         char *cp, errmsg[STRERR_BUFSIZE];
3825         int err = 0;
3826
3827         if (mkdir(path, 0700) && errno != EEXIST)
3828                 err = -errno;
3829
3830         if (err) {
3831                 cp = libbpf_strerror_r(-err, errmsg, sizeof(errmsg));
3832                 pr_warning("failed to mkdir %s: %s\n", path, cp);
3833         }
3834         return err;
3835 }
3836
3837 int bpf_program__pin(struct bpf_program *prog, const char *path)
3838 {
3839         int i, err;
3840
3841         err = check_path(path);
3842         if (err)
3843                 return err;
3844
3845         if (prog == NULL) {
3846                 pr_warning("invalid program pointer\n");
3847                 return -EINVAL;
3848         }
3849
3850         if (prog->instances.nr <= 0) {
3851                 pr_warning("no instances of prog %s to pin\n",
3852                            prog->section_name);
3853                 return -EINVAL;
3854         }
3855
3856         if (prog->instances.nr == 1) {
3857                 /* don't create subdirs when pinning single instance */
3858                 return bpf_program__pin_instance(prog, path, 0);
3859         }
3860
3861         err = make_dir(path);
3862         if (err)
3863                 return err;
3864
3865         for (i = 0; i < prog->instances.nr; i++) {
3866                 char buf[PATH_MAX];
3867                 int len;
3868
3869                 len = snprintf(buf, PATH_MAX, "%s/%d", path, i);
3870                 if (len < 0) {
3871                         err = -EINVAL;
3872                         goto err_unpin;
3873                 } else if (len >= PATH_MAX) {
3874                         err = -ENAMETOOLONG;
3875                         goto err_unpin;
3876                 }
3877
3878                 err = bpf_program__pin_instance(prog, buf, i);
3879                 if (err)
3880                         goto err_unpin;
3881         }
3882
3883         return 0;
3884
3885 err_unpin:
3886         for (i = i - 1; i >= 0; i--) {
3887                 char buf[PATH_MAX];
3888                 int len;
3889
3890                 len = snprintf(buf, PATH_MAX, "%s/%d", path, i);
3891                 if (len < 0)
3892                         continue;
3893                 else if (len >= PATH_MAX)
3894                         continue;
3895
3896                 bpf_program__unpin_instance(prog, buf, i);
3897         }
3898
3899         rmdir(path);
3900
3901         return err;
3902 }
3903
3904 int bpf_program__unpin(struct bpf_program *prog, const char *path)
3905 {
3906         int i, err;
3907
3908         err = check_path(path);
3909         if (err)
3910                 return err;
3911
3912         if (prog == NULL) {
3913                 pr_warning("invalid program pointer\n");
3914                 return -EINVAL;
3915         }
3916
3917         if (prog->instances.nr <= 0) {
3918                 pr_warning("no instances of prog %s to pin\n",
3919                            prog->section_name);
3920                 return -EINVAL;
3921         }
3922
3923         if (prog->instances.nr == 1) {
3924                 /* don't create subdirs when pinning single instance */
3925                 return bpf_program__unpin_instance(prog, path, 0);
3926         }
3927
3928         for (i = 0; i < prog->instances.nr; i++) {
3929                 char buf[PATH_MAX];
3930                 int len;
3931
3932                 len = snprintf(buf, PATH_MAX, "%s/%d", path, i);
3933                 if (len < 0)
3934                         return -EINVAL;
3935                 else if (len >= PATH_MAX)
3936                         return -ENAMETOOLONG;
3937
3938                 err = bpf_program__unpin_instance(prog, buf, i);
3939                 if (err)
3940                         return err;
3941         }
3942
3943         err = rmdir(path);
3944         if (err)
3945                 return -errno;
3946
3947         return 0;
3948 }
3949
3950 int bpf_map__pin(struct bpf_map *map, const char *path)
3951 {
3952         char *cp, errmsg[STRERR_BUFSIZE];
3953         int err;
3954
3955         err = check_path(path);
3956         if (err)
3957                 return err;
3958
3959         if (map == NULL) {
3960                 pr_warning("invalid map pointer\n");
3961                 return -EINVAL;
3962         }
3963
3964         if (bpf_obj_pin(map->fd, path)) {
3965                 cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg));
3966                 pr_warning("failed to pin map: %s\n", cp);
3967                 return -errno;
3968         }
3969
3970         pr_debug("pinned map '%s'\n", path);
3971
3972         return 0;
3973 }
3974
3975 int bpf_map__unpin(struct bpf_map *map, const char *path)
3976 {
3977         int err;
3978
3979         err = check_path(path);
3980         if (err)
3981                 return err;
3982
3983         if (map == NULL) {
3984                 pr_warning("invalid map pointer\n");
3985                 return -EINVAL;
3986         }
3987
3988         err = unlink(path);
3989         if (err != 0)
3990                 return -errno;
3991         pr_debug("unpinned map '%s'\n", path);
3992
3993         return 0;
3994 }
3995
3996 int bpf_object__pin_maps(struct bpf_object *obj, const char *path)
3997 {
3998         struct bpf_map *map;
3999         int err;
4000
4001         if (!obj)
4002                 return -ENOENT;
4003
4004         if (!obj->loaded) {
4005                 pr_warning("object not yet loaded; load it first\n");
4006                 return -ENOENT;
4007         }
4008
4009         err = make_dir(path);
4010         if (err)
4011                 return err;
4012
4013         bpf_object__for_each_map(map, obj) {
4014                 char buf[PATH_MAX];
4015                 int len;
4016
4017                 len = snprintf(buf, PATH_MAX, "%s/%s", path,
4018                                bpf_map__name(map));
4019                 if (len < 0) {
4020                         err = -EINVAL;
4021                         goto err_unpin_maps;
4022                 } else if (len >= PATH_MAX) {
4023                         err = -ENAMETOOLONG;
4024                         goto err_unpin_maps;
4025                 }
4026
4027                 err = bpf_map__pin(map, buf);
4028                 if (err)
4029                         goto err_unpin_maps;
4030         }
4031
4032         return 0;
4033
4034 err_unpin_maps:
4035         while ((map = bpf_map__prev(map, obj))) {
4036                 char buf[PATH_MAX];
4037                 int len;
4038
4039                 len = snprintf(buf, PATH_MAX, "%s/%s", path,
4040                                bpf_map__name(map));
4041                 if (len < 0)
4042                         continue;
4043                 else if (len >= PATH_MAX)
4044                         continue;
4045
4046                 bpf_map__unpin(map, buf);
4047         }
4048
4049         return err;
4050 }
4051
4052 int bpf_object__unpin_maps(struct bpf_object *obj, const char *path)
4053 {
4054         struct bpf_map *map;
4055         int err;
4056
4057         if (!obj)
4058                 return -ENOENT;
4059
4060         bpf_object__for_each_map(map, obj) {
4061                 char buf[PATH_MAX];
4062                 int len;
4063
4064                 len = snprintf(buf, PATH_MAX, "%s/%s", path,
4065                                bpf_map__name(map));
4066                 if (len < 0)
4067                         return -EINVAL;
4068                 else if (len >= PATH_MAX)
4069                         return -ENAMETOOLONG;
4070
4071                 err = bpf_map__unpin(map, buf);
4072                 if (err)
4073                         return err;
4074         }
4075
4076         return 0;
4077 }
4078
4079 int bpf_object__pin_programs(struct bpf_object *obj, const char *path)
4080 {
4081         struct bpf_program *prog;
4082         int err;
4083
4084         if (!obj)
4085                 return -ENOENT;
4086
4087         if (!obj->loaded) {
4088                 pr_warning("object not yet loaded; load it first\n");
4089                 return -ENOENT;
4090         }
4091
4092         err = make_dir(path);
4093         if (err)
4094                 return err;
4095
4096         bpf_object__for_each_program(prog, obj) {
4097                 char buf[PATH_MAX];
4098                 int len;
4099
4100                 len = snprintf(buf, PATH_MAX, "%s/%s", path,
4101                                prog->pin_name);
4102                 if (len < 0) {
4103                         err = -EINVAL;
4104                         goto err_unpin_programs;
4105                 } else if (len >= PATH_MAX) {
4106                         err = -ENAMETOOLONG;
4107                         goto err_unpin_programs;
4108                 }
4109
4110                 err = bpf_program__pin(prog, buf);
4111                 if (err)
4112                         goto err_unpin_programs;
4113         }
4114
4115         return 0;
4116
4117 err_unpin_programs:
4118         while ((prog = bpf_program__prev(prog, obj))) {
4119                 char buf[PATH_MAX];
4120                 int len;
4121
4122                 len = snprintf(buf, PATH_MAX, "%s/%s", path,
4123                                prog->pin_name);
4124                 if (len < 0)
4125                         continue;
4126                 else if (len >= PATH_MAX)
4127                         continue;
4128
4129                 bpf_program__unpin(prog, buf);
4130         }
4131
4132         return err;
4133 }
4134
4135 int bpf_object__unpin_programs(struct bpf_object *obj, const char *path)
4136 {
4137         struct bpf_program *prog;
4138         int err;
4139
4140         if (!obj)
4141                 return -ENOENT;
4142
4143         bpf_object__for_each_program(prog, obj) {
4144                 char buf[PATH_MAX];
4145                 int len;
4146
4147                 len = snprintf(buf, PATH_MAX, "%s/%s", path,
4148                                prog->pin_name);
4149                 if (len < 0)
4150                         return -EINVAL;
4151                 else if (len >= PATH_MAX)
4152                         return -ENAMETOOLONG;
4153
4154                 err = bpf_program__unpin(prog, buf);
4155                 if (err)
4156                         return err;
4157         }
4158
4159         return 0;
4160 }
4161
4162 int bpf_object__pin(struct bpf_object *obj, const char *path)
4163 {
4164         int err;
4165
4166         err = bpf_object__pin_maps(obj, path);
4167         if (err)
4168                 return err;
4169
4170         err = bpf_object__pin_programs(obj, path);
4171         if (err) {
4172                 bpf_object__unpin_maps(obj, path);
4173                 return err;
4174         }
4175
4176         return 0;
4177 }
4178
4179 void bpf_object__close(struct bpf_object *obj)
4180 {
4181         size_t i;
4182
4183         if (!obj)
4184                 return;
4185
4186         if (obj->clear_priv)
4187                 obj->clear_priv(obj, obj->priv);
4188
4189         bpf_object__elf_finish(obj);
4190         bpf_object__unload(obj);
4191         btf__free(obj->btf);
4192         btf_ext__free(obj->btf_ext);
4193
4194         for (i = 0; i < obj->nr_maps; i++) {
4195                 zfree(&obj->maps[i].name);
4196                 if (obj->maps[i].clear_priv)
4197                         obj->maps[i].clear_priv(&obj->maps[i],
4198                                                 obj->maps[i].priv);
4199                 obj->maps[i].priv = NULL;
4200                 obj->maps[i].clear_priv = NULL;
4201         }
4202
4203         zfree(&obj->sections.rodata);
4204         zfree(&obj->sections.data);
4205         zfree(&obj->maps);
4206         obj->nr_maps = 0;
4207
4208         if (obj->programs && obj->nr_programs) {
4209                 for (i = 0; i < obj->nr_programs; i++)
4210                         bpf_program__exit(&obj->programs[i]);
4211         }
4212         zfree(&obj->programs);
4213
4214         list_del(&obj->list);
4215         free(obj);
4216 }
4217
4218 struct bpf_object *
4219 bpf_object__next(struct bpf_object *prev)
4220 {
4221         struct bpf_object *next;
4222
4223         if (!prev)
4224                 next = list_first_entry(&bpf_objects_list,
4225                                         struct bpf_object,
4226                                         list);
4227         else
4228                 next = list_next_entry(prev, list);
4229
4230         /* Empty list is noticed here so don't need checking on entry. */
4231         if (&next->list == &bpf_objects_list)
4232                 return NULL;
4233
4234         return next;
4235 }
4236
4237 const char *bpf_object__name(const struct bpf_object *obj)
4238 {
4239         return obj ? obj->path : ERR_PTR(-EINVAL);
4240 }
4241
4242 unsigned int bpf_object__kversion(const struct bpf_object *obj)
4243 {
4244         return obj ? obj->kern_version : 0;
4245 }
4246
4247 struct btf *bpf_object__btf(const struct bpf_object *obj)
4248 {
4249         return obj ? obj->btf : NULL;
4250 }
4251
4252 int bpf_object__btf_fd(const struct bpf_object *obj)
4253 {
4254         return obj->btf ? btf__fd(obj->btf) : -1;
4255 }
4256
4257 int bpf_object__set_priv(struct bpf_object *obj, void *priv,
4258                          bpf_object_clear_priv_t clear_priv)
4259 {
4260         if (obj->priv && obj->clear_priv)
4261                 obj->clear_priv(obj, obj->priv);
4262
4263         obj->priv = priv;
4264         obj->clear_priv = clear_priv;
4265         return 0;
4266 }
4267
4268 void *bpf_object__priv(const struct bpf_object *obj)
4269 {
4270         return obj ? obj->priv : ERR_PTR(-EINVAL);
4271 }
4272
4273 static struct bpf_program *
4274 __bpf_program__iter(const struct bpf_program *p, const struct bpf_object *obj,
4275                     bool forward)
4276 {
4277         size_t nr_programs = obj->nr_programs;
4278         ssize_t idx;
4279
4280         if (!nr_programs)
4281                 return NULL;
4282
4283         if (!p)
4284                 /* Iter from the beginning */
4285                 return forward ? &obj->programs[0] :
4286                         &obj->programs[nr_programs - 1];
4287
4288         if (p->obj != obj) {
4289                 pr_warning("error: program handler doesn't match object\n");
4290                 return NULL;
4291         }
4292
4293         idx = (p - obj->programs) + (forward ? 1 : -1);
4294         if (idx >= obj->nr_programs || idx < 0)
4295                 return NULL;
4296         return &obj->programs[idx];
4297 }
4298
4299 struct bpf_program *
4300 bpf_program__next(struct bpf_program *prev, const struct bpf_object *obj)
4301 {
4302         struct bpf_program *prog = prev;
4303
4304         do {
4305                 prog = __bpf_program__iter(prog, obj, true);
4306         } while (prog && bpf_program__is_function_storage(prog, obj));
4307
4308         return prog;
4309 }
4310
4311 struct bpf_program *
4312 bpf_program__prev(struct bpf_program *next, const struct bpf_object *obj)
4313 {
4314         struct bpf_program *prog = next;
4315
4316         do {
4317                 prog = __bpf_program__iter(prog, obj, false);
4318         } while (prog && bpf_program__is_function_storage(prog, obj));
4319
4320         return prog;
4321 }
4322
4323 int bpf_program__set_priv(struct bpf_program *prog, void *priv,
4324                           bpf_program_clear_priv_t clear_priv)
4325 {
4326         if (prog->priv && prog->clear_priv)
4327                 prog->clear_priv(prog, prog->priv);
4328
4329         prog->priv = priv;
4330         prog->clear_priv = clear_priv;
4331         return 0;
4332 }
4333
4334 void *bpf_program__priv(const struct bpf_program *prog)
4335 {
4336         return prog ? prog->priv : ERR_PTR(-EINVAL);
4337 }
4338
4339 void bpf_program__set_ifindex(struct bpf_program *prog, __u32 ifindex)
4340 {
4341         prog->prog_ifindex = ifindex;
4342 }
4343
4344 const char *bpf_program__title(const struct bpf_program *prog, bool needs_copy)
4345 {
4346         const char *title;
4347
4348         title = prog->section_name;
4349         if (needs_copy) {
4350                 title = strdup(title);
4351                 if (!title) {
4352                         pr_warning("failed to strdup program title\n");
4353                         return ERR_PTR(-ENOMEM);
4354                 }
4355         }
4356
4357         return title;
4358 }
4359
4360 int bpf_program__fd(const struct bpf_program *prog)
4361 {
4362         return bpf_program__nth_fd(prog, 0);
4363 }
4364
4365 int bpf_program__set_prep(struct bpf_program *prog, int nr_instances,
4366                           bpf_program_prep_t prep)
4367 {
4368         int *instances_fds;
4369
4370         if (nr_instances <= 0 || !prep)
4371                 return -EINVAL;
4372
4373         if (prog->instances.nr > 0 || prog->instances.fds) {
4374                 pr_warning("Can't set pre-processor after loading\n");
4375                 return -EINVAL;
4376         }
4377
4378         instances_fds = malloc(sizeof(int) * nr_instances);
4379         if (!instances_fds) {
4380                 pr_warning("alloc memory failed for fds\n");
4381                 return -ENOMEM;
4382         }
4383
4384         /* fill all fd with -1 */
4385         memset(instances_fds, -1, sizeof(int) * nr_instances);
4386
4387         prog->instances.nr = nr_instances;
4388         prog->instances.fds = instances_fds;
4389         prog->preprocessor = prep;
4390         return 0;
4391 }
4392
4393 int bpf_program__nth_fd(const struct bpf_program *prog, int n)
4394 {
4395         int fd;
4396
4397         if (!prog)
4398                 return -EINVAL;
4399
4400         if (n >= prog->instances.nr || n < 0) {
4401                 pr_warning("Can't get the %dth fd from program %s: only %d instances\n",
4402                            n, prog->section_name, prog->instances.nr);
4403                 return -EINVAL;
4404         }
4405
4406         fd = prog->instances.fds[n];
4407         if (fd < 0) {
4408                 pr_warning("%dth instance of program '%s' is invalid\n",
4409                            n, prog->section_name);
4410                 return -ENOENT;
4411         }
4412
4413         return fd;
4414 }
4415
4416 void bpf_program__set_type(struct bpf_program *prog, enum bpf_prog_type type)
4417 {
4418         prog->type = type;
4419 }
4420
4421 static bool bpf_program__is_type(const struct bpf_program *prog,
4422                                  enum bpf_prog_type type)
4423 {
4424         return prog ? (prog->type == type) : false;
4425 }
4426
4427 #define BPF_PROG_TYPE_FNS(NAME, TYPE)                           \
4428 int bpf_program__set_##NAME(struct bpf_program *prog)           \
4429 {                                                               \
4430         if (!prog)                                              \
4431                 return -EINVAL;                                 \
4432         bpf_program__set_type(prog, TYPE);                      \
4433         return 0;                                               \
4434 }                                                               \
4435                                                                 \
4436 bool bpf_program__is_##NAME(const struct bpf_program *prog)     \
4437 {                                                               \
4438         return bpf_program__is_type(prog, TYPE);                \
4439 }                                                               \
4440
4441 BPF_PROG_TYPE_FNS(socket_filter, BPF_PROG_TYPE_SOCKET_FILTER);
4442 BPF_PROG_TYPE_FNS(kprobe, BPF_PROG_TYPE_KPROBE);
4443 BPF_PROG_TYPE_FNS(sched_cls, BPF_PROG_TYPE_SCHED_CLS);
4444 BPF_PROG_TYPE_FNS(sched_act, BPF_PROG_TYPE_SCHED_ACT);
4445 BPF_PROG_TYPE_FNS(tracepoint, BPF_PROG_TYPE_TRACEPOINT);
4446 BPF_PROG_TYPE_FNS(raw_tracepoint, BPF_PROG_TYPE_RAW_TRACEPOINT);
4447 BPF_PROG_TYPE_FNS(xdp, BPF_PROG_TYPE_XDP);
4448 BPF_PROG_TYPE_FNS(perf_event, BPF_PROG_TYPE_PERF_EVENT);
4449
4450 void bpf_program__set_expected_attach_type(struct bpf_program *prog,
4451                                            enum bpf_attach_type type)
4452 {
4453         prog->expected_attach_type = type;
4454 }
4455
4456 #define BPF_PROG_SEC_IMPL(string, ptype, eatype, is_attachable, atype) \
4457         { string, sizeof(string) - 1, ptype, eatype, is_attachable, atype }
4458
4459 /* Programs that can NOT be attached. */
4460 #define BPF_PROG_SEC(string, ptype) BPF_PROG_SEC_IMPL(string, ptype, 0, 0, 0)
4461
4462 /* Programs that can be attached. */
4463 #define BPF_APROG_SEC(string, ptype, atype) \
4464         BPF_PROG_SEC_IMPL(string, ptype, 0, 1, atype)
4465
4466 /* Programs that must specify expected attach type at load time. */
4467 #define BPF_EAPROG_SEC(string, ptype, eatype) \
4468         BPF_PROG_SEC_IMPL(string, ptype, eatype, 1, eatype)
4469
4470 /* Programs that can be attached but attach type can't be identified by section
4471  * name. Kept for backward compatibility.
4472  */
4473 #define BPF_APROG_COMPAT(string, ptype) BPF_PROG_SEC(string, ptype)
4474
4475 static const struct {
4476         const char *sec;
4477         size_t len;
4478         enum bpf_prog_type prog_type;
4479         enum bpf_attach_type expected_attach_type;
4480         int is_attachable;
4481         enum bpf_attach_type attach_type;
4482 } section_names[] = {
4483         BPF_PROG_SEC("socket",                  BPF_PROG_TYPE_SOCKET_FILTER),
4484         BPF_PROG_SEC("kprobe/",                 BPF_PROG_TYPE_KPROBE),
4485         BPF_PROG_SEC("kretprobe/",              BPF_PROG_TYPE_KPROBE),
4486         BPF_PROG_SEC("classifier",              BPF_PROG_TYPE_SCHED_CLS),
4487         BPF_PROG_SEC("action",                  BPF_PROG_TYPE_SCHED_ACT),
4488         BPF_PROG_SEC("tracepoint/",             BPF_PROG_TYPE_TRACEPOINT),
4489         BPF_PROG_SEC("raw_tracepoint/",         BPF_PROG_TYPE_RAW_TRACEPOINT),
4490         BPF_PROG_SEC("xdp",                     BPF_PROG_TYPE_XDP),
4491         BPF_PROG_SEC("perf_event",              BPF_PROG_TYPE_PERF_EVENT),
4492         BPF_PROG_SEC("lwt_in",                  BPF_PROG_TYPE_LWT_IN),
4493         BPF_PROG_SEC("lwt_out",                 BPF_PROG_TYPE_LWT_OUT),
4494         BPF_PROG_SEC("lwt_xmit",                BPF_PROG_TYPE_LWT_XMIT),
4495         BPF_PROG_SEC("lwt_seg6local",           BPF_PROG_TYPE_LWT_SEG6LOCAL),
4496         BPF_APROG_SEC("cgroup_skb/ingress",     BPF_PROG_TYPE_CGROUP_SKB,
4497                                                 BPF_CGROUP_INET_INGRESS),
4498         BPF_APROG_SEC("cgroup_skb/egress",      BPF_PROG_TYPE_CGROUP_SKB,
4499                                                 BPF_CGROUP_INET_EGRESS),
4500         BPF_APROG_COMPAT("cgroup/skb",          BPF_PROG_TYPE_CGROUP_SKB),
4501         BPF_APROG_SEC("cgroup/sock",            BPF_PROG_TYPE_CGROUP_SOCK,
4502                                                 BPF_CGROUP_INET_SOCK_CREATE),
4503         BPF_EAPROG_SEC("cgroup/post_bind4",     BPF_PROG_TYPE_CGROUP_SOCK,
4504                                                 BPF_CGROUP_INET4_POST_BIND),
4505         BPF_EAPROG_SEC("cgroup/post_bind6",     BPF_PROG_TYPE_CGROUP_SOCK,
4506                                                 BPF_CGROUP_INET6_POST_BIND),
4507         BPF_APROG_SEC("cgroup/dev",             BPF_PROG_TYPE_CGROUP_DEVICE,
4508                                                 BPF_CGROUP_DEVICE),
4509         BPF_APROG_SEC("sockops",                BPF_PROG_TYPE_SOCK_OPS,
4510                                                 BPF_CGROUP_SOCK_OPS),
4511         BPF_APROG_SEC("sk_skb/stream_parser",   BPF_PROG_TYPE_SK_SKB,
4512                                                 BPF_SK_SKB_STREAM_PARSER),
4513         BPF_APROG_SEC("sk_skb/stream_verdict",  BPF_PROG_TYPE_SK_SKB,
4514                                                 BPF_SK_SKB_STREAM_VERDICT),
4515         BPF_APROG_COMPAT("sk_skb",              BPF_PROG_TYPE_SK_SKB),
4516         BPF_APROG_SEC("sk_msg",                 BPF_PROG_TYPE_SK_MSG,
4517                                                 BPF_SK_MSG_VERDICT),
4518         BPF_APROG_SEC("lirc_mode2",             BPF_PROG_TYPE_LIRC_MODE2,
4519                                                 BPF_LIRC_MODE2),
4520         BPF_APROG_SEC("flow_dissector",         BPF_PROG_TYPE_FLOW_DISSECTOR,
4521                                                 BPF_FLOW_DISSECTOR),
4522         BPF_EAPROG_SEC("cgroup/bind4",          BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
4523                                                 BPF_CGROUP_INET4_BIND),
4524         BPF_EAPROG_SEC("cgroup/bind6",          BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
4525                                                 BPF_CGROUP_INET6_BIND),
4526         BPF_EAPROG_SEC("cgroup/connect4",       BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
4527                                                 BPF_CGROUP_INET4_CONNECT),
4528         BPF_EAPROG_SEC("cgroup/connect6",       BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
4529                                                 BPF_CGROUP_INET6_CONNECT),
4530         BPF_EAPROG_SEC("cgroup/sendmsg4",       BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
4531                                                 BPF_CGROUP_UDP4_SENDMSG),
4532         BPF_EAPROG_SEC("cgroup/sendmsg6",       BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
4533                                                 BPF_CGROUP_UDP6_SENDMSG),
4534         BPF_EAPROG_SEC("cgroup/recvmsg4",       BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
4535                                                 BPF_CGROUP_UDP4_RECVMSG),
4536         BPF_EAPROG_SEC("cgroup/recvmsg6",       BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
4537                                                 BPF_CGROUP_UDP6_RECVMSG),
4538         BPF_EAPROG_SEC("cgroup/sysctl",         BPF_PROG_TYPE_CGROUP_SYSCTL,
4539                                                 BPF_CGROUP_SYSCTL),
4540         BPF_EAPROG_SEC("cgroup/getsockopt",     BPF_PROG_TYPE_CGROUP_SOCKOPT,
4541                                                 BPF_CGROUP_GETSOCKOPT),
4542         BPF_EAPROG_SEC("cgroup/setsockopt",     BPF_PROG_TYPE_CGROUP_SOCKOPT,
4543                                                 BPF_CGROUP_SETSOCKOPT),
4544 };
4545
4546 #undef BPF_PROG_SEC_IMPL
4547 #undef BPF_PROG_SEC
4548 #undef BPF_APROG_SEC
4549 #undef BPF_EAPROG_SEC
4550 #undef BPF_APROG_COMPAT
4551
4552 #define MAX_TYPE_NAME_SIZE 32
4553
4554 static char *libbpf_get_type_names(bool attach_type)
4555 {
4556         int i, len = ARRAY_SIZE(section_names) * MAX_TYPE_NAME_SIZE;
4557         char *buf;
4558
4559         buf = malloc(len);
4560         if (!buf)
4561                 return NULL;
4562
4563         buf[0] = '\0';
4564         /* Forge string buf with all available names */
4565         for (i = 0; i < ARRAY_SIZE(section_names); i++) {
4566                 if (attach_type && !section_names[i].is_attachable)
4567                         continue;
4568
4569                 if (strlen(buf) + strlen(section_names[i].sec) + 2 > len) {
4570                         free(buf);
4571                         return NULL;
4572                 }
4573                 strcat(buf, " ");
4574                 strcat(buf, section_names[i].sec);
4575         }
4576
4577         return buf;
4578 }
4579
4580 int libbpf_prog_type_by_name(const char *name, enum bpf_prog_type *prog_type,
4581                              enum bpf_attach_type *expected_attach_type)
4582 {
4583         char *type_names;
4584         int i;
4585
4586         if (!name)
4587                 return -EINVAL;
4588
4589         for (i = 0; i < ARRAY_SIZE(section_names); i++) {
4590                 if (strncmp(name, section_names[i].sec, section_names[i].len))
4591                         continue;
4592                 *prog_type = section_names[i].prog_type;
4593                 *expected_attach_type = section_names[i].expected_attach_type;
4594                 return 0;
4595         }
4596         pr_warning("failed to guess program type based on ELF section name '%s'\n", name);
4597         type_names = libbpf_get_type_names(false);
4598         if (type_names != NULL) {
4599                 pr_info("supported section(type) names are:%s\n", type_names);
4600                 free(type_names);
4601         }
4602
4603         return -EINVAL;
4604 }
4605
4606 int libbpf_attach_type_by_name(const char *name,
4607                                enum bpf_attach_type *attach_type)
4608 {
4609         char *type_names;
4610         int i;
4611
4612         if (!name)
4613                 return -EINVAL;
4614
4615         for (i = 0; i < ARRAY_SIZE(section_names); i++) {
4616                 if (strncmp(name, section_names[i].sec, section_names[i].len))
4617                         continue;
4618                 if (!section_names[i].is_attachable)
4619                         return -EINVAL;
4620                 *attach_type = section_names[i].attach_type;
4621                 return 0;
4622         }
4623         pr_warning("failed to guess attach type based on ELF section name '%s'\n", name);
4624         type_names = libbpf_get_type_names(true);
4625         if (type_names != NULL) {
4626                 pr_info("attachable section(type) names are:%s\n", type_names);
4627                 free(type_names);
4628         }
4629
4630         return -EINVAL;
4631 }
4632
4633 static int
4634 bpf_program__identify_section(struct bpf_program *prog,
4635                               enum bpf_prog_type *prog_type,
4636                               enum bpf_attach_type *expected_attach_type)
4637 {
4638         return libbpf_prog_type_by_name(prog->section_name, prog_type,
4639                                         expected_attach_type);
4640 }
4641
4642 int bpf_map__fd(const struct bpf_map *map)
4643 {
4644         return map ? map->fd : -EINVAL;
4645 }
4646
4647 const struct bpf_map_def *bpf_map__def(const struct bpf_map *map)
4648 {
4649         return map ? &map->def : ERR_PTR(-EINVAL);
4650 }
4651
4652 const char *bpf_map__name(const struct bpf_map *map)
4653 {
4654         return map ? map->name : NULL;
4655 }
4656
4657 __u32 bpf_map__btf_key_type_id(const struct bpf_map *map)
4658 {
4659         return map ? map->btf_key_type_id : 0;
4660 }
4661
4662 __u32 bpf_map__btf_value_type_id(const struct bpf_map *map)
4663 {
4664         return map ? map->btf_value_type_id : 0;
4665 }
4666
4667 int bpf_map__set_priv(struct bpf_map *map, void *priv,
4668                      bpf_map_clear_priv_t clear_priv)
4669 {
4670         if (!map)
4671                 return -EINVAL;
4672
4673         if (map->priv) {
4674                 if (map->clear_priv)
4675                         map->clear_priv(map, map->priv);
4676         }
4677
4678         map->priv = priv;
4679         map->clear_priv = clear_priv;
4680         return 0;
4681 }
4682
4683 void *bpf_map__priv(const struct bpf_map *map)
4684 {
4685         return map ? map->priv : ERR_PTR(-EINVAL);
4686 }
4687
4688 bool bpf_map__is_offload_neutral(const struct bpf_map *map)
4689 {
4690         return map->def.type == BPF_MAP_TYPE_PERF_EVENT_ARRAY;
4691 }
4692
4693 bool bpf_map__is_internal(const struct bpf_map *map)
4694 {
4695         return map->libbpf_type != LIBBPF_MAP_UNSPEC;
4696 }
4697
4698 void bpf_map__set_ifindex(struct bpf_map *map, __u32 ifindex)
4699 {
4700         map->map_ifindex = ifindex;
4701 }
4702
4703 int bpf_map__set_inner_map_fd(struct bpf_map *map, int fd)
4704 {
4705         if (!bpf_map_type__is_map_in_map(map->def.type)) {
4706                 pr_warning("error: unsupported map type\n");
4707                 return -EINVAL;
4708         }
4709         if (map->inner_map_fd != -1) {
4710                 pr_warning("error: inner_map_fd already specified\n");
4711                 return -EINVAL;
4712         }
4713         map->inner_map_fd = fd;
4714         return 0;
4715 }
4716
4717 static struct bpf_map *
4718 __bpf_map__iter(const struct bpf_map *m, const struct bpf_object *obj, int i)
4719 {
4720         ssize_t idx;
4721         struct bpf_map *s, *e;
4722
4723         if (!obj || !obj->maps)
4724                 return NULL;
4725
4726         s = obj->maps;
4727         e = obj->maps + obj->nr_maps;
4728
4729         if ((m < s) || (m >= e)) {
4730                 pr_warning("error in %s: map handler doesn't belong to object\n",
4731                            __func__);
4732                 return NULL;
4733         }
4734
4735         idx = (m - obj->maps) + i;
4736         if (idx >= obj->nr_maps || idx < 0)
4737                 return NULL;
4738         return &obj->maps[idx];
4739 }
4740
4741 struct bpf_map *
4742 bpf_map__next(const struct bpf_map *prev, const struct bpf_object *obj)
4743 {
4744         if (prev == NULL)
4745                 return obj->maps;
4746
4747         return __bpf_map__iter(prev, obj, 1);
4748 }
4749
4750 struct bpf_map *
4751 bpf_map__prev(const struct bpf_map *next, const struct bpf_object *obj)
4752 {
4753         if (next == NULL) {
4754                 if (!obj->nr_maps)
4755                         return NULL;
4756                 return obj->maps + obj->nr_maps - 1;
4757         }
4758
4759         return __bpf_map__iter(next, obj, -1);
4760 }
4761
4762 struct bpf_map *
4763 bpf_object__find_map_by_name(const struct bpf_object *obj, const char *name)
4764 {
4765         struct bpf_map *pos;
4766
4767         bpf_object__for_each_map(pos, obj) {
4768                 if (pos->name && !strcmp(pos->name, name))
4769                         return pos;
4770         }
4771         return NULL;
4772 }
4773
4774 int
4775 bpf_object__find_map_fd_by_name(const struct bpf_object *obj, const char *name)
4776 {
4777         return bpf_map__fd(bpf_object__find_map_by_name(obj, name));
4778 }
4779
4780 struct bpf_map *
4781 bpf_object__find_map_by_offset(struct bpf_object *obj, size_t offset)
4782 {
4783         return ERR_PTR(-ENOTSUP);
4784 }
4785
4786 long libbpf_get_error(const void *ptr)
4787 {
4788         return PTR_ERR_OR_ZERO(ptr);
4789 }
4790
4791 int bpf_prog_load(const char *file, enum bpf_prog_type type,
4792                   struct bpf_object **pobj, int *prog_fd)
4793 {
4794         struct bpf_prog_load_attr attr;
4795
4796         memset(&attr, 0, sizeof(struct bpf_prog_load_attr));
4797         attr.file = file;
4798         attr.prog_type = type;
4799         attr.expected_attach_type = 0;
4800
4801         return bpf_prog_load_xattr(&attr, pobj, prog_fd);
4802 }
4803
4804 int bpf_prog_load_xattr(const struct bpf_prog_load_attr *attr,
4805                         struct bpf_object **pobj, int *prog_fd)
4806 {
4807         struct bpf_object_open_attr open_attr = {};
4808         struct bpf_program *prog, *first_prog = NULL;
4809         enum bpf_attach_type expected_attach_type;
4810         enum bpf_prog_type prog_type;
4811         struct bpf_object *obj;
4812         struct bpf_map *map;
4813         int err;
4814
4815         if (!attr)
4816                 return -EINVAL;
4817         if (!attr->file)
4818                 return -EINVAL;
4819
4820         open_attr.file = attr->file;
4821         open_attr.prog_type = attr->prog_type;
4822
4823         obj = bpf_object__open_xattr(&open_attr);
4824         if (IS_ERR_OR_NULL(obj))
4825                 return -ENOENT;
4826
4827         bpf_object__for_each_program(prog, obj) {
4828                 /*
4829                  * If type is not specified, try to guess it based on
4830                  * section name.
4831                  */
4832                 prog_type = attr->prog_type;
4833                 prog->prog_ifindex = attr->ifindex;
4834                 expected_attach_type = attr->expected_attach_type;
4835                 if (prog_type == BPF_PROG_TYPE_UNSPEC) {
4836                         err = bpf_program__identify_section(prog, &prog_type,
4837                                                             &expected_attach_type);
4838                         if (err < 0) {
4839                                 bpf_object__close(obj);
4840                                 return -EINVAL;
4841                         }
4842                 }
4843
4844                 bpf_program__set_type(prog, prog_type);
4845                 bpf_program__set_expected_attach_type(prog,
4846                                                       expected_attach_type);
4847
4848                 prog->log_level = attr->log_level;
4849                 prog->prog_flags = attr->prog_flags;
4850                 if (!first_prog)
4851                         first_prog = prog;
4852         }
4853
4854         bpf_object__for_each_map(map, obj) {
4855                 if (!bpf_map__is_offload_neutral(map))
4856                         map->map_ifindex = attr->ifindex;
4857         }
4858
4859         if (!first_prog) {
4860                 pr_warning("object file doesn't contain bpf program\n");
4861                 bpf_object__close(obj);
4862                 return -ENOENT;
4863         }
4864
4865         err = bpf_object__load(obj);
4866         if (err) {
4867                 bpf_object__close(obj);
4868                 return -EINVAL;
4869         }
4870
4871         *pobj = obj;
4872         *prog_fd = bpf_program__fd(first_prog);
4873         return 0;
4874 }
4875
4876 struct bpf_link {
4877         int (*destroy)(struct bpf_link *link);
4878 };
4879
4880 int bpf_link__destroy(struct bpf_link *link)
4881 {
4882         int err;
4883
4884         if (!link)
4885                 return 0;
4886
4887         err = link->destroy(link);
4888         free(link);
4889
4890         return err;
4891 }
4892
4893 struct bpf_link_fd {
4894         struct bpf_link link; /* has to be at the top of struct */
4895         int fd; /* hook FD */
4896 };
4897
4898 static int bpf_link__destroy_perf_event(struct bpf_link *link)
4899 {
4900         struct bpf_link_fd *l = (void *)link;
4901         int err;
4902
4903         err = ioctl(l->fd, PERF_EVENT_IOC_DISABLE, 0);
4904         if (err)
4905                 err = -errno;
4906
4907         close(l->fd);
4908         return err;
4909 }
4910
4911 struct bpf_link *bpf_program__attach_perf_event(struct bpf_program *prog,
4912                                                 int pfd)
4913 {
4914         char errmsg[STRERR_BUFSIZE];
4915         struct bpf_link_fd *link;
4916         int prog_fd, err;
4917
4918         if (pfd < 0) {
4919                 pr_warning("program '%s': invalid perf event FD %d\n",
4920                            bpf_program__title(prog, false), pfd);
4921                 return ERR_PTR(-EINVAL);
4922         }
4923         prog_fd = bpf_program__fd(prog);
4924         if (prog_fd < 0) {
4925                 pr_warning("program '%s': can't attach BPF program w/o FD (did you load it?)\n",
4926                            bpf_program__title(prog, false));
4927                 return ERR_PTR(-EINVAL);
4928         }
4929
4930         link = malloc(sizeof(*link));
4931         if (!link)
4932                 return ERR_PTR(-ENOMEM);
4933         link->link.destroy = &bpf_link__destroy_perf_event;
4934         link->fd = pfd;
4935
4936         if (ioctl(pfd, PERF_EVENT_IOC_SET_BPF, prog_fd) < 0) {
4937                 err = -errno;
4938                 free(link);
4939                 pr_warning("program '%s': failed to attach to pfd %d: %s\n",
4940                            bpf_program__title(prog, false), pfd,
4941                            libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
4942                 return ERR_PTR(err);
4943         }
4944         if (ioctl(pfd, PERF_EVENT_IOC_ENABLE, 0) < 0) {
4945                 err = -errno;
4946                 free(link);
4947                 pr_warning("program '%s': failed to enable pfd %d: %s\n",
4948                            bpf_program__title(prog, false), pfd,
4949                            libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
4950                 return ERR_PTR(err);
4951         }
4952         return (struct bpf_link *)link;
4953 }
4954
4955 /*
4956  * this function is expected to parse integer in the range of [0, 2^31-1] from
4957  * given file using scanf format string fmt. If actual parsed value is
4958  * negative, the result might be indistinguishable from error
4959  */
4960 static int parse_uint_from_file(const char *file, const char *fmt)
4961 {
4962         char buf[STRERR_BUFSIZE];
4963         int err, ret;
4964         FILE *f;
4965
4966         f = fopen(file, "r");
4967         if (!f) {
4968                 err = -errno;
4969                 pr_debug("failed to open '%s': %s\n", file,
4970                          libbpf_strerror_r(err, buf, sizeof(buf)));
4971                 return err;
4972         }
4973         err = fscanf(f, fmt, &ret);
4974         if (err != 1) {
4975                 err = err == EOF ? -EIO : -errno;
4976                 pr_debug("failed to parse '%s': %s\n", file,
4977                         libbpf_strerror_r(err, buf, sizeof(buf)));
4978                 fclose(f);
4979                 return err;
4980         }
4981         fclose(f);
4982         return ret;
4983 }
4984
4985 static int determine_kprobe_perf_type(void)
4986 {
4987         const char *file = "/sys/bus/event_source/devices/kprobe/type";
4988
4989         return parse_uint_from_file(file, "%d\n");
4990 }
4991
4992 static int determine_uprobe_perf_type(void)
4993 {
4994         const char *file = "/sys/bus/event_source/devices/uprobe/type";
4995
4996         return parse_uint_from_file(file, "%d\n");
4997 }
4998
4999 static int determine_kprobe_retprobe_bit(void)
5000 {
5001         const char *file = "/sys/bus/event_source/devices/kprobe/format/retprobe";
5002
5003         return parse_uint_from_file(file, "config:%d\n");
5004 }
5005
5006 static int determine_uprobe_retprobe_bit(void)
5007 {
5008         const char *file = "/sys/bus/event_source/devices/uprobe/format/retprobe";
5009
5010         return parse_uint_from_file(file, "config:%d\n");
5011 }
5012
5013 static int perf_event_open_probe(bool uprobe, bool retprobe, const char *name,
5014                                  uint64_t offset, int pid)
5015 {
5016         struct perf_event_attr attr = {};
5017         char errmsg[STRERR_BUFSIZE];
5018         int type, pfd, err;
5019
5020         type = uprobe ? determine_uprobe_perf_type()
5021                       : determine_kprobe_perf_type();
5022         if (type < 0) {
5023                 pr_warning("failed to determine %s perf type: %s\n",
5024                            uprobe ? "uprobe" : "kprobe",
5025                            libbpf_strerror_r(type, errmsg, sizeof(errmsg)));
5026                 return type;
5027         }
5028         if (retprobe) {
5029                 int bit = uprobe ? determine_uprobe_retprobe_bit()
5030                                  : determine_kprobe_retprobe_bit();
5031
5032                 if (bit < 0) {
5033                         pr_warning("failed to determine %s retprobe bit: %s\n",
5034                                    uprobe ? "uprobe" : "kprobe",
5035                                    libbpf_strerror_r(bit, errmsg,
5036                                                      sizeof(errmsg)));
5037                         return bit;
5038                 }
5039                 attr.config |= 1 << bit;
5040         }
5041         attr.size = sizeof(attr);
5042         attr.type = type;
5043         attr.config1 = ptr_to_u64(name); /* kprobe_func or uprobe_path */
5044         attr.config2 = offset;           /* kprobe_addr or probe_offset */
5045
5046         /* pid filter is meaningful only for uprobes */
5047         pfd = syscall(__NR_perf_event_open, &attr,
5048                       pid < 0 ? -1 : pid /* pid */,
5049                       pid == -1 ? 0 : -1 /* cpu */,
5050                       -1 /* group_fd */, PERF_FLAG_FD_CLOEXEC);
5051         if (pfd < 0) {
5052                 err = -errno;
5053                 pr_warning("%s perf_event_open() failed: %s\n",
5054                            uprobe ? "uprobe" : "kprobe",
5055                            libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
5056                 return err;
5057         }
5058         return pfd;
5059 }
5060
5061 struct bpf_link *bpf_program__attach_kprobe(struct bpf_program *prog,
5062                                             bool retprobe,
5063                                             const char *func_name)
5064 {
5065         char errmsg[STRERR_BUFSIZE];
5066         struct bpf_link *link;
5067         int pfd, err;
5068
5069         pfd = perf_event_open_probe(false /* uprobe */, retprobe, func_name,
5070                                     0 /* offset */, -1 /* pid */);
5071         if (pfd < 0) {
5072                 pr_warning("program '%s': failed to create %s '%s' perf event: %s\n",
5073                            bpf_program__title(prog, false),
5074                            retprobe ? "kretprobe" : "kprobe", func_name,
5075                            libbpf_strerror_r(pfd, errmsg, sizeof(errmsg)));
5076                 return ERR_PTR(pfd);
5077         }
5078         link = bpf_program__attach_perf_event(prog, pfd);
5079         if (IS_ERR(link)) {
5080                 close(pfd);
5081                 err = PTR_ERR(link);
5082                 pr_warning("program '%s': failed to attach to %s '%s': %s\n",
5083                            bpf_program__title(prog, false),
5084                            retprobe ? "kretprobe" : "kprobe", func_name,
5085                            libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
5086                 return link;
5087         }
5088         return link;
5089 }
5090
5091 struct bpf_link *bpf_program__attach_uprobe(struct bpf_program *prog,
5092                                             bool retprobe, pid_t pid,
5093                                             const char *binary_path,
5094                                             size_t func_offset)
5095 {
5096         char errmsg[STRERR_BUFSIZE];
5097         struct bpf_link *link;
5098         int pfd, err;
5099
5100         pfd = perf_event_open_probe(true /* uprobe */, retprobe,
5101                                     binary_path, func_offset, pid);
5102         if (pfd < 0) {
5103                 pr_warning("program '%s': failed to create %s '%s:0x%zx' perf event: %s\n",
5104                            bpf_program__title(prog, false),
5105                            retprobe ? "uretprobe" : "uprobe",
5106                            binary_path, func_offset,
5107                            libbpf_strerror_r(pfd, errmsg, sizeof(errmsg)));
5108                 return ERR_PTR(pfd);
5109         }
5110         link = bpf_program__attach_perf_event(prog, pfd);
5111         if (IS_ERR(link)) {
5112                 close(pfd);
5113                 err = PTR_ERR(link);
5114                 pr_warning("program '%s': failed to attach to %s '%s:0x%zx': %s\n",
5115                            bpf_program__title(prog, false),
5116                            retprobe ? "uretprobe" : "uprobe",
5117                            binary_path, func_offset,
5118                            libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
5119                 return link;
5120         }
5121         return link;
5122 }
5123
5124 static int determine_tracepoint_id(const char *tp_category,
5125                                    const char *tp_name)
5126 {
5127         char file[PATH_MAX];
5128         int ret;
5129
5130         ret = snprintf(file, sizeof(file),
5131                        "/sys/kernel/debug/tracing/events/%s/%s/id",
5132                        tp_category, tp_name);
5133         if (ret < 0)
5134                 return -errno;
5135         if (ret >= sizeof(file)) {
5136                 pr_debug("tracepoint %s/%s path is too long\n",
5137                          tp_category, tp_name);
5138                 return -E2BIG;
5139         }
5140         return parse_uint_from_file(file, "%d\n");
5141 }
5142
5143 static int perf_event_open_tracepoint(const char *tp_category,
5144                                       const char *tp_name)
5145 {
5146         struct perf_event_attr attr = {};
5147         char errmsg[STRERR_BUFSIZE];
5148         int tp_id, pfd, err;
5149
5150         tp_id = determine_tracepoint_id(tp_category, tp_name);
5151         if (tp_id < 0) {
5152                 pr_warning("failed to determine tracepoint '%s/%s' perf event ID: %s\n",
5153                            tp_category, tp_name,
5154                            libbpf_strerror_r(tp_id, errmsg, sizeof(errmsg)));
5155                 return tp_id;
5156         }
5157
5158         attr.type = PERF_TYPE_TRACEPOINT;
5159         attr.size = sizeof(attr);
5160         attr.config = tp_id;
5161
5162         pfd = syscall(__NR_perf_event_open, &attr, -1 /* pid */, 0 /* cpu */,
5163                       -1 /* group_fd */, PERF_FLAG_FD_CLOEXEC);
5164         if (pfd < 0) {
5165                 err = -errno;
5166                 pr_warning("tracepoint '%s/%s' perf_event_open() failed: %s\n",
5167                            tp_category, tp_name,
5168                            libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
5169                 return err;
5170         }
5171         return pfd;
5172 }
5173
5174 struct bpf_link *bpf_program__attach_tracepoint(struct bpf_program *prog,
5175                                                 const char *tp_category,
5176                                                 const char *tp_name)
5177 {
5178         char errmsg[STRERR_BUFSIZE];
5179         struct bpf_link *link;
5180         int pfd, err;
5181
5182         pfd = perf_event_open_tracepoint(tp_category, tp_name);
5183         if (pfd < 0) {
5184                 pr_warning("program '%s': failed to create tracepoint '%s/%s' perf event: %s\n",
5185                            bpf_program__title(prog, false),
5186                            tp_category, tp_name,
5187                            libbpf_strerror_r(pfd, errmsg, sizeof(errmsg)));
5188                 return ERR_PTR(pfd);
5189         }
5190         link = bpf_program__attach_perf_event(prog, pfd);
5191         if (IS_ERR(link)) {
5192                 close(pfd);
5193                 err = PTR_ERR(link);
5194                 pr_warning("program '%s': failed to attach to tracepoint '%s/%s': %s\n",
5195                            bpf_program__title(prog, false),
5196                            tp_category, tp_name,
5197                            libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
5198                 return link;
5199         }
5200         return link;
5201 }
5202
5203 static int bpf_link__destroy_fd(struct bpf_link *link)
5204 {
5205         struct bpf_link_fd *l = (void *)link;
5206
5207         return close(l->fd);
5208 }
5209
5210 struct bpf_link *bpf_program__attach_raw_tracepoint(struct bpf_program *prog,
5211                                                     const char *tp_name)
5212 {
5213         char errmsg[STRERR_BUFSIZE];
5214         struct bpf_link_fd *link;
5215         int prog_fd, pfd;
5216
5217         prog_fd = bpf_program__fd(prog);
5218         if (prog_fd < 0) {
5219                 pr_warning("program '%s': can't attach before loaded\n",
5220                            bpf_program__title(prog, false));
5221                 return ERR_PTR(-EINVAL);
5222         }
5223
5224         link = malloc(sizeof(*link));
5225         if (!link)
5226                 return ERR_PTR(-ENOMEM);
5227         link->link.destroy = &bpf_link__destroy_fd;
5228
5229         pfd = bpf_raw_tracepoint_open(tp_name, prog_fd);
5230         if (pfd < 0) {
5231                 pfd = -errno;
5232                 free(link);
5233                 pr_warning("program '%s': failed to attach to raw tracepoint '%s': %s\n",
5234                            bpf_program__title(prog, false), tp_name,
5235                            libbpf_strerror_r(pfd, errmsg, sizeof(errmsg)));
5236                 return ERR_PTR(pfd);
5237         }
5238         link->fd = pfd;
5239         return (struct bpf_link *)link;
5240 }
5241
5242 enum bpf_perf_event_ret
5243 bpf_perf_event_read_simple(void *mmap_mem, size_t mmap_size, size_t page_size,
5244                            void **copy_mem, size_t *copy_size,
5245                            bpf_perf_event_print_t fn, void *private_data)
5246 {
5247         struct perf_event_mmap_page *header = mmap_mem;
5248         __u64 data_head = ring_buffer_read_head(header);
5249         __u64 data_tail = header->data_tail;
5250         void *base = ((__u8 *)header) + page_size;
5251         int ret = LIBBPF_PERF_EVENT_CONT;
5252         struct perf_event_header *ehdr;
5253         size_t ehdr_size;
5254
5255         while (data_head != data_tail) {
5256                 ehdr = base + (data_tail & (mmap_size - 1));
5257                 ehdr_size = ehdr->size;
5258
5259                 if (((void *)ehdr) + ehdr_size > base + mmap_size) {
5260                         void *copy_start = ehdr;
5261                         size_t len_first = base + mmap_size - copy_start;
5262                         size_t len_secnd = ehdr_size - len_first;
5263
5264                         if (*copy_size < ehdr_size) {
5265                                 free(*copy_mem);
5266                                 *copy_mem = malloc(ehdr_size);
5267                                 if (!*copy_mem) {
5268                                         *copy_size = 0;
5269                                         ret = LIBBPF_PERF_EVENT_ERROR;
5270                                         break;
5271                                 }
5272                                 *copy_size = ehdr_size;
5273                         }
5274
5275                         memcpy(*copy_mem, copy_start, len_first);
5276                         memcpy(*copy_mem + len_first, base, len_secnd);
5277                         ehdr = *copy_mem;
5278                 }
5279
5280                 ret = fn(ehdr, private_data);
5281                 data_tail += ehdr_size;
5282                 if (ret != LIBBPF_PERF_EVENT_CONT)
5283                         break;
5284         }
5285
5286         ring_buffer_write_tail(header, data_tail);
5287         return ret;
5288 }
5289
5290 struct perf_buffer;
5291
5292 struct perf_buffer_params {
5293         struct perf_event_attr *attr;
5294         /* if event_cb is specified, it takes precendence */
5295         perf_buffer_event_fn event_cb;
5296         /* sample_cb and lost_cb are higher-level common-case callbacks */
5297         perf_buffer_sample_fn sample_cb;
5298         perf_buffer_lost_fn lost_cb;
5299         void *ctx;
5300         int cpu_cnt;
5301         int *cpus;
5302         int *map_keys;
5303 };
5304
5305 struct perf_cpu_buf {
5306         struct perf_buffer *pb;
5307         void *base; /* mmap()'ed memory */
5308         void *buf; /* for reconstructing segmented data */
5309         size_t buf_size;
5310         int fd;
5311         int cpu;
5312         int map_key;
5313 };
5314
5315 struct perf_buffer {
5316         perf_buffer_event_fn event_cb;
5317         perf_buffer_sample_fn sample_cb;
5318         perf_buffer_lost_fn lost_cb;
5319         void *ctx; /* passed into callbacks */
5320
5321         size_t page_size;
5322         size_t mmap_size;
5323         struct perf_cpu_buf **cpu_bufs;
5324         struct epoll_event *events;
5325         int cpu_cnt;
5326         int epoll_fd; /* perf event FD */
5327         int map_fd; /* BPF_MAP_TYPE_PERF_EVENT_ARRAY BPF map FD */
5328 };
5329
5330 static void perf_buffer__free_cpu_buf(struct perf_buffer *pb,
5331                                       struct perf_cpu_buf *cpu_buf)
5332 {
5333         if (!cpu_buf)
5334                 return;
5335         if (cpu_buf->base &&
5336             munmap(cpu_buf->base, pb->mmap_size + pb->page_size))
5337                 pr_warning("failed to munmap cpu_buf #%d\n", cpu_buf->cpu);
5338         if (cpu_buf->fd >= 0) {
5339                 ioctl(cpu_buf->fd, PERF_EVENT_IOC_DISABLE, 0);
5340                 close(cpu_buf->fd);
5341         }
5342         free(cpu_buf->buf);
5343         free(cpu_buf);
5344 }
5345
5346 void perf_buffer__free(struct perf_buffer *pb)
5347 {
5348         int i;
5349
5350         if (!pb)
5351                 return;
5352         if (pb->cpu_bufs) {
5353                 for (i = 0; i < pb->cpu_cnt && pb->cpu_bufs[i]; i++) {
5354                         struct perf_cpu_buf *cpu_buf = pb->cpu_bufs[i];
5355
5356                         bpf_map_delete_elem(pb->map_fd, &cpu_buf->map_key);
5357                         perf_buffer__free_cpu_buf(pb, cpu_buf);
5358                 }
5359                 free(pb->cpu_bufs);
5360         }
5361         if (pb->epoll_fd >= 0)
5362                 close(pb->epoll_fd);
5363         free(pb->events);
5364         free(pb);
5365 }
5366
5367 static struct perf_cpu_buf *
5368 perf_buffer__open_cpu_buf(struct perf_buffer *pb, struct perf_event_attr *attr,
5369                           int cpu, int map_key)
5370 {
5371         struct perf_cpu_buf *cpu_buf;
5372         char msg[STRERR_BUFSIZE];
5373         int err;
5374
5375         cpu_buf = calloc(1, sizeof(*cpu_buf));
5376         if (!cpu_buf)
5377                 return ERR_PTR(-ENOMEM);
5378
5379         cpu_buf->pb = pb;
5380         cpu_buf->cpu = cpu;
5381         cpu_buf->map_key = map_key;
5382
5383         cpu_buf->fd = syscall(__NR_perf_event_open, attr, -1 /* pid */, cpu,
5384                               -1, PERF_FLAG_FD_CLOEXEC);
5385         if (cpu_buf->fd < 0) {
5386                 err = -errno;
5387                 pr_warning("failed to open perf buffer event on cpu #%d: %s\n",
5388                            cpu, libbpf_strerror_r(err, msg, sizeof(msg)));
5389                 goto error;
5390         }
5391
5392         cpu_buf->base = mmap(NULL, pb->mmap_size + pb->page_size,
5393                              PROT_READ | PROT_WRITE, MAP_SHARED,
5394                              cpu_buf->fd, 0);
5395         if (cpu_buf->base == MAP_FAILED) {
5396                 cpu_buf->base = NULL;
5397                 err = -errno;
5398                 pr_warning("failed to mmap perf buffer on cpu #%d: %s\n",
5399                            cpu, libbpf_strerror_r(err, msg, sizeof(msg)));
5400                 goto error;
5401         }
5402
5403         if (ioctl(cpu_buf->fd, PERF_EVENT_IOC_ENABLE, 0) < 0) {
5404                 err = -errno;
5405                 pr_warning("failed to enable perf buffer event on cpu #%d: %s\n",
5406                            cpu, libbpf_strerror_r(err, msg, sizeof(msg)));
5407                 goto error;
5408         }
5409
5410         return cpu_buf;
5411
5412 error:
5413         perf_buffer__free_cpu_buf(pb, cpu_buf);
5414         return (struct perf_cpu_buf *)ERR_PTR(err);
5415 }
5416
5417 static struct perf_buffer *__perf_buffer__new(int map_fd, size_t page_cnt,
5418                                               struct perf_buffer_params *p);
5419
5420 struct perf_buffer *perf_buffer__new(int map_fd, size_t page_cnt,
5421                                      const struct perf_buffer_opts *opts)
5422 {
5423         struct perf_buffer_params p = {};
5424         struct perf_event_attr attr = { 0, };
5425
5426         attr.config = PERF_COUNT_SW_BPF_OUTPUT,
5427         attr.type = PERF_TYPE_SOFTWARE;
5428         attr.sample_type = PERF_SAMPLE_RAW;
5429         attr.sample_period = 1;
5430         attr.wakeup_events = 1;
5431
5432         p.attr = &attr;
5433         p.sample_cb = opts ? opts->sample_cb : NULL;
5434         p.lost_cb = opts ? opts->lost_cb : NULL;
5435         p.ctx = opts ? opts->ctx : NULL;
5436
5437         return __perf_buffer__new(map_fd, page_cnt, &p);
5438 }
5439
5440 struct perf_buffer *
5441 perf_buffer__new_raw(int map_fd, size_t page_cnt,
5442                      const struct perf_buffer_raw_opts *opts)
5443 {
5444         struct perf_buffer_params p = {};
5445
5446         p.attr = opts->attr;
5447         p.event_cb = opts->event_cb;
5448         p.ctx = opts->ctx;
5449         p.cpu_cnt = opts->cpu_cnt;
5450         p.cpus = opts->cpus;
5451         p.map_keys = opts->map_keys;
5452
5453         return __perf_buffer__new(map_fd, page_cnt, &p);
5454 }
5455
5456 static struct perf_buffer *__perf_buffer__new(int map_fd, size_t page_cnt,
5457                                               struct perf_buffer_params *p)
5458 {
5459         struct bpf_map_info map = {};
5460         char msg[STRERR_BUFSIZE];
5461         struct perf_buffer *pb;
5462         __u32 map_info_len;
5463         int err, i;
5464
5465         if (page_cnt & (page_cnt - 1)) {
5466                 pr_warning("page count should be power of two, but is %zu\n",
5467                            page_cnt);
5468                 return ERR_PTR(-EINVAL);
5469         }
5470
5471         map_info_len = sizeof(map);
5472         err = bpf_obj_get_info_by_fd(map_fd, &map, &map_info_len);
5473         if (err) {
5474                 err = -errno;
5475                 pr_warning("failed to get map info for map FD %d: %s\n",
5476                            map_fd, libbpf_strerror_r(err, msg, sizeof(msg)));
5477                 return ERR_PTR(err);
5478         }
5479
5480         if (map.type != BPF_MAP_TYPE_PERF_EVENT_ARRAY) {
5481                 pr_warning("map '%s' should be BPF_MAP_TYPE_PERF_EVENT_ARRAY\n",
5482                            map.name);
5483                 return ERR_PTR(-EINVAL);
5484         }
5485
5486         pb = calloc(1, sizeof(*pb));
5487         if (!pb)
5488                 return ERR_PTR(-ENOMEM);
5489
5490         pb->event_cb = p->event_cb;
5491         pb->sample_cb = p->sample_cb;
5492         pb->lost_cb = p->lost_cb;
5493         pb->ctx = p->ctx;
5494
5495         pb->page_size = getpagesize();
5496         pb->mmap_size = pb->page_size * page_cnt;
5497         pb->map_fd = map_fd;
5498
5499         pb->epoll_fd = epoll_create1(EPOLL_CLOEXEC);
5500         if (pb->epoll_fd < 0) {
5501                 err = -errno;
5502                 pr_warning("failed to create epoll instance: %s\n",
5503                            libbpf_strerror_r(err, msg, sizeof(msg)));
5504                 goto error;
5505         }
5506
5507         if (p->cpu_cnt > 0) {
5508                 pb->cpu_cnt = p->cpu_cnt;
5509         } else {
5510                 pb->cpu_cnt = libbpf_num_possible_cpus();
5511                 if (pb->cpu_cnt < 0) {
5512                         err = pb->cpu_cnt;
5513                         goto error;
5514                 }
5515                 if (map.max_entries < pb->cpu_cnt)
5516                         pb->cpu_cnt = map.max_entries;
5517         }
5518
5519         pb->events = calloc(pb->cpu_cnt, sizeof(*pb->events));
5520         if (!pb->events) {
5521                 err = -ENOMEM;
5522                 pr_warning("failed to allocate events: out of memory\n");
5523                 goto error;
5524         }
5525         pb->cpu_bufs = calloc(pb->cpu_cnt, sizeof(*pb->cpu_bufs));
5526         if (!pb->cpu_bufs) {
5527                 err = -ENOMEM;
5528                 pr_warning("failed to allocate buffers: out of memory\n");
5529                 goto error;
5530         }
5531
5532         for (i = 0; i < pb->cpu_cnt; i++) {
5533                 struct perf_cpu_buf *cpu_buf;
5534                 int cpu, map_key;
5535
5536                 cpu = p->cpu_cnt > 0 ? p->cpus[i] : i;
5537                 map_key = p->cpu_cnt > 0 ? p->map_keys[i] : i;
5538
5539                 cpu_buf = perf_buffer__open_cpu_buf(pb, p->attr, cpu, map_key);
5540                 if (IS_ERR(cpu_buf)) {
5541                         err = PTR_ERR(cpu_buf);
5542                         goto error;
5543                 }
5544
5545                 pb->cpu_bufs[i] = cpu_buf;
5546
5547                 err = bpf_map_update_elem(pb->map_fd, &map_key,
5548                                           &cpu_buf->fd, 0);
5549                 if (err) {
5550                         err = -errno;
5551                         pr_warning("failed to set cpu #%d, key %d -> perf FD %d: %s\n",
5552                                    cpu, map_key, cpu_buf->fd,
5553                                    libbpf_strerror_r(err, msg, sizeof(msg)));
5554                         goto error;
5555                 }
5556
5557                 pb->events[i].events = EPOLLIN;
5558                 pb->events[i].data.ptr = cpu_buf;
5559                 if (epoll_ctl(pb->epoll_fd, EPOLL_CTL_ADD, cpu_buf->fd,
5560                               &pb->events[i]) < 0) {
5561                         err = -errno;
5562                         pr_warning("failed to epoll_ctl cpu #%d perf FD %d: %s\n",
5563                                    cpu, cpu_buf->fd,
5564                                    libbpf_strerror_r(err, msg, sizeof(msg)));
5565                         goto error;
5566                 }
5567         }
5568
5569         return pb;
5570
5571 error:
5572         if (pb)
5573                 perf_buffer__free(pb);
5574         return ERR_PTR(err);
5575 }
5576
5577 struct perf_sample_raw {
5578         struct perf_event_header header;
5579         uint32_t size;
5580         char data[0];
5581 };
5582
5583 struct perf_sample_lost {
5584         struct perf_event_header header;
5585         uint64_t id;
5586         uint64_t lost;
5587         uint64_t sample_id;
5588 };
5589
5590 static enum bpf_perf_event_ret
5591 perf_buffer__process_record(struct perf_event_header *e, void *ctx)
5592 {
5593         struct perf_cpu_buf *cpu_buf = ctx;
5594         struct perf_buffer *pb = cpu_buf->pb;
5595         void *data = e;
5596
5597         /* user wants full control over parsing perf event */
5598         if (pb->event_cb)
5599                 return pb->event_cb(pb->ctx, cpu_buf->cpu, e);
5600
5601         switch (e->type) {
5602         case PERF_RECORD_SAMPLE: {
5603                 struct perf_sample_raw *s = data;
5604
5605                 if (pb->sample_cb)
5606                         pb->sample_cb(pb->ctx, cpu_buf->cpu, s->data, s->size);
5607                 break;
5608         }
5609         case PERF_RECORD_LOST: {
5610                 struct perf_sample_lost *s = data;
5611
5612                 if (pb->lost_cb)
5613                         pb->lost_cb(pb->ctx, cpu_buf->cpu, s->lost);
5614                 break;
5615         }
5616         default:
5617                 pr_warning("unknown perf sample type %d\n", e->type);
5618                 return LIBBPF_PERF_EVENT_ERROR;
5619         }
5620         return LIBBPF_PERF_EVENT_CONT;
5621 }
5622
5623 static int perf_buffer__process_records(struct perf_buffer *pb,
5624                                         struct perf_cpu_buf *cpu_buf)
5625 {
5626         enum bpf_perf_event_ret ret;
5627
5628         ret = bpf_perf_event_read_simple(cpu_buf->base, pb->mmap_size,
5629                                          pb->page_size, &cpu_buf->buf,
5630                                          &cpu_buf->buf_size,
5631                                          perf_buffer__process_record, cpu_buf);
5632         if (ret != LIBBPF_PERF_EVENT_CONT)
5633                 return ret;
5634         return 0;
5635 }
5636
5637 int perf_buffer__poll(struct perf_buffer *pb, int timeout_ms)
5638 {
5639         int i, cnt, err;
5640
5641         cnt = epoll_wait(pb->epoll_fd, pb->events, pb->cpu_cnt, timeout_ms);
5642         for (i = 0; i < cnt; i++) {
5643                 struct perf_cpu_buf *cpu_buf = pb->events[i].data.ptr;
5644
5645                 err = perf_buffer__process_records(pb, cpu_buf);
5646                 if (err) {
5647                         pr_warning("error while processing records: %d\n", err);
5648                         return err;
5649                 }
5650         }
5651         return cnt < 0 ? -errno : cnt;
5652 }
5653
5654 struct bpf_prog_info_array_desc {
5655         int     array_offset;   /* e.g. offset of jited_prog_insns */
5656         int     count_offset;   /* e.g. offset of jited_prog_len */
5657         int     size_offset;    /* > 0: offset of rec size,
5658                                  * < 0: fix size of -size_offset
5659                                  */
5660 };
5661
5662 static struct bpf_prog_info_array_desc bpf_prog_info_array_desc[] = {
5663         [BPF_PROG_INFO_JITED_INSNS] = {
5664                 offsetof(struct bpf_prog_info, jited_prog_insns),
5665                 offsetof(struct bpf_prog_info, jited_prog_len),
5666                 -1,
5667         },
5668         [BPF_PROG_INFO_XLATED_INSNS] = {
5669                 offsetof(struct bpf_prog_info, xlated_prog_insns),
5670                 offsetof(struct bpf_prog_info, xlated_prog_len),
5671                 -1,
5672         },
5673         [BPF_PROG_INFO_MAP_IDS] = {
5674                 offsetof(struct bpf_prog_info, map_ids),
5675                 offsetof(struct bpf_prog_info, nr_map_ids),
5676                 -(int)sizeof(__u32),
5677         },
5678         [BPF_PROG_INFO_JITED_KSYMS] = {
5679                 offsetof(struct bpf_prog_info, jited_ksyms),
5680                 offsetof(struct bpf_prog_info, nr_jited_ksyms),
5681                 -(int)sizeof(__u64),
5682         },
5683         [BPF_PROG_INFO_JITED_FUNC_LENS] = {
5684                 offsetof(struct bpf_prog_info, jited_func_lens),
5685                 offsetof(struct bpf_prog_info, nr_jited_func_lens),
5686                 -(int)sizeof(__u32),
5687         },
5688         [BPF_PROG_INFO_FUNC_INFO] = {
5689                 offsetof(struct bpf_prog_info, func_info),
5690                 offsetof(struct bpf_prog_info, nr_func_info),
5691                 offsetof(struct bpf_prog_info, func_info_rec_size),
5692         },
5693         [BPF_PROG_INFO_LINE_INFO] = {
5694                 offsetof(struct bpf_prog_info, line_info),
5695                 offsetof(struct bpf_prog_info, nr_line_info),
5696                 offsetof(struct bpf_prog_info, line_info_rec_size),
5697         },
5698         [BPF_PROG_INFO_JITED_LINE_INFO] = {
5699                 offsetof(struct bpf_prog_info, jited_line_info),
5700                 offsetof(struct bpf_prog_info, nr_jited_line_info),
5701                 offsetof(struct bpf_prog_info, jited_line_info_rec_size),
5702         },
5703         [BPF_PROG_INFO_PROG_TAGS] = {
5704                 offsetof(struct bpf_prog_info, prog_tags),
5705                 offsetof(struct bpf_prog_info, nr_prog_tags),
5706                 -(int)sizeof(__u8) * BPF_TAG_SIZE,
5707         },
5708
5709 };
5710
5711 static __u32 bpf_prog_info_read_offset_u32(struct bpf_prog_info *info, int offset)
5712 {
5713         __u32 *array = (__u32 *)info;
5714
5715         if (offset >= 0)
5716                 return array[offset / sizeof(__u32)];
5717         return -(int)offset;
5718 }
5719
5720 static __u64 bpf_prog_info_read_offset_u64(struct bpf_prog_info *info, int offset)
5721 {
5722         __u64 *array = (__u64 *)info;
5723
5724         if (offset >= 0)
5725                 return array[offset / sizeof(__u64)];
5726         return -(int)offset;
5727 }
5728
5729 static void bpf_prog_info_set_offset_u32(struct bpf_prog_info *info, int offset,
5730                                          __u32 val)
5731 {
5732         __u32 *array = (__u32 *)info;
5733
5734         if (offset >= 0)
5735                 array[offset / sizeof(__u32)] = val;
5736 }
5737
5738 static void bpf_prog_info_set_offset_u64(struct bpf_prog_info *info, int offset,
5739                                          __u64 val)
5740 {
5741         __u64 *array = (__u64 *)info;
5742
5743         if (offset >= 0)
5744                 array[offset / sizeof(__u64)] = val;
5745 }
5746
5747 struct bpf_prog_info_linear *
5748 bpf_program__get_prog_info_linear(int fd, __u64 arrays)
5749 {
5750         struct bpf_prog_info_linear *info_linear;
5751         struct bpf_prog_info info = {};
5752         __u32 info_len = sizeof(info);
5753         __u32 data_len = 0;
5754         int i, err;
5755         void *ptr;
5756
5757         if (arrays >> BPF_PROG_INFO_LAST_ARRAY)
5758                 return ERR_PTR(-EINVAL);
5759
5760         /* step 1: get array dimensions */
5761         err = bpf_obj_get_info_by_fd(fd, &info, &info_len);
5762         if (err) {
5763                 pr_debug("can't get prog info: %s", strerror(errno));
5764                 return ERR_PTR(-EFAULT);
5765         }
5766
5767         /* step 2: calculate total size of all arrays */
5768         for (i = BPF_PROG_INFO_FIRST_ARRAY; i < BPF_PROG_INFO_LAST_ARRAY; ++i) {
5769                 bool include_array = (arrays & (1UL << i)) > 0;
5770                 struct bpf_prog_info_array_desc *desc;
5771                 __u32 count, size;
5772
5773                 desc = bpf_prog_info_array_desc + i;
5774
5775                 /* kernel is too old to support this field */
5776                 if (info_len < desc->array_offset + sizeof(__u32) ||
5777                     info_len < desc->count_offset + sizeof(__u32) ||
5778                     (desc->size_offset > 0 && info_len < desc->size_offset))
5779                         include_array = false;
5780
5781                 if (!include_array) {
5782                         arrays &= ~(1UL << i);  /* clear the bit */
5783                         continue;
5784                 }
5785
5786                 count = bpf_prog_info_read_offset_u32(&info, desc->count_offset);
5787                 size  = bpf_prog_info_read_offset_u32(&info, desc->size_offset);
5788
5789                 data_len += count * size;
5790         }
5791
5792         /* step 3: allocate continuous memory */
5793         data_len = roundup(data_len, sizeof(__u64));
5794         info_linear = malloc(sizeof(struct bpf_prog_info_linear) + data_len);
5795         if (!info_linear)
5796                 return ERR_PTR(-ENOMEM);
5797
5798         /* step 4: fill data to info_linear->info */
5799         info_linear->arrays = arrays;
5800         memset(&info_linear->info, 0, sizeof(info));
5801         ptr = info_linear->data;
5802
5803         for (i = BPF_PROG_INFO_FIRST_ARRAY; i < BPF_PROG_INFO_LAST_ARRAY; ++i) {
5804                 struct bpf_prog_info_array_desc *desc;
5805                 __u32 count, size;
5806
5807                 if ((arrays & (1UL << i)) == 0)
5808                         continue;
5809
5810                 desc  = bpf_prog_info_array_desc + i;
5811                 count = bpf_prog_info_read_offset_u32(&info, desc->count_offset);
5812                 size  = bpf_prog_info_read_offset_u32(&info, desc->size_offset);
5813                 bpf_prog_info_set_offset_u32(&info_linear->info,
5814                                              desc->count_offset, count);
5815                 bpf_prog_info_set_offset_u32(&info_linear->info,
5816                                              desc->size_offset, size);
5817                 bpf_prog_info_set_offset_u64(&info_linear->info,
5818                                              desc->array_offset,
5819                                              ptr_to_u64(ptr));
5820                 ptr += count * size;
5821         }
5822
5823         /* step 5: call syscall again to get required arrays */
5824         err = bpf_obj_get_info_by_fd(fd, &info_linear->info, &info_len);
5825         if (err) {
5826                 pr_debug("can't get prog info: %s", strerror(errno));
5827                 free(info_linear);
5828                 return ERR_PTR(-EFAULT);
5829         }
5830
5831         /* step 6: verify the data */
5832         for (i = BPF_PROG_INFO_FIRST_ARRAY; i < BPF_PROG_INFO_LAST_ARRAY; ++i) {
5833                 struct bpf_prog_info_array_desc *desc;
5834                 __u32 v1, v2;
5835
5836                 if ((arrays & (1UL << i)) == 0)
5837                         continue;
5838
5839                 desc = bpf_prog_info_array_desc + i;
5840                 v1 = bpf_prog_info_read_offset_u32(&info, desc->count_offset);
5841                 v2 = bpf_prog_info_read_offset_u32(&info_linear->info,
5842                                                    desc->count_offset);
5843                 if (v1 != v2)
5844                         pr_warning("%s: mismatch in element count\n", __func__);
5845
5846                 v1 = bpf_prog_info_read_offset_u32(&info, desc->size_offset);
5847                 v2 = bpf_prog_info_read_offset_u32(&info_linear->info,
5848                                                    desc->size_offset);
5849                 if (v1 != v2)
5850                         pr_warning("%s: mismatch in rec size\n", __func__);
5851         }
5852
5853         /* step 7: update info_len and data_len */
5854         info_linear->info_len = sizeof(struct bpf_prog_info);
5855         info_linear->data_len = data_len;
5856
5857         return info_linear;
5858 }
5859
5860 void bpf_program__bpil_addr_to_offs(struct bpf_prog_info_linear *info_linear)
5861 {
5862         int i;
5863
5864         for (i = BPF_PROG_INFO_FIRST_ARRAY; i < BPF_PROG_INFO_LAST_ARRAY; ++i) {
5865                 struct bpf_prog_info_array_desc *desc;
5866                 __u64 addr, offs;
5867
5868                 if ((info_linear->arrays & (1UL << i)) == 0)
5869                         continue;
5870
5871                 desc = bpf_prog_info_array_desc + i;
5872                 addr = bpf_prog_info_read_offset_u64(&info_linear->info,
5873                                                      desc->array_offset);
5874                 offs = addr - ptr_to_u64(info_linear->data);
5875                 bpf_prog_info_set_offset_u64(&info_linear->info,
5876                                              desc->array_offset, offs);
5877         }
5878 }
5879
5880 void bpf_program__bpil_offs_to_addr(struct bpf_prog_info_linear *info_linear)
5881 {
5882         int i;
5883
5884         for (i = BPF_PROG_INFO_FIRST_ARRAY; i < BPF_PROG_INFO_LAST_ARRAY; ++i) {
5885                 struct bpf_prog_info_array_desc *desc;
5886                 __u64 addr, offs;
5887
5888                 if ((info_linear->arrays & (1UL << i)) == 0)
5889                         continue;
5890
5891                 desc = bpf_prog_info_array_desc + i;
5892                 offs = bpf_prog_info_read_offset_u64(&info_linear->info,
5893                                                      desc->array_offset);
5894                 addr = offs + ptr_to_u64(info_linear->data);
5895                 bpf_prog_info_set_offset_u64(&info_linear->info,
5896                                              desc->array_offset, addr);
5897         }
5898 }
5899
5900 int libbpf_num_possible_cpus(void)
5901 {
5902         static const char *fcpu = "/sys/devices/system/cpu/possible";
5903         int len = 0, n = 0, il = 0, ir = 0;
5904         unsigned int start = 0, end = 0;
5905         int tmp_cpus = 0;
5906         static int cpus;
5907         char buf[128];
5908         int error = 0;
5909         int fd = -1;
5910
5911         tmp_cpus = READ_ONCE(cpus);
5912         if (tmp_cpus > 0)
5913                 return tmp_cpus;
5914
5915         fd = open(fcpu, O_RDONLY);
5916         if (fd < 0) {
5917                 error = errno;
5918                 pr_warning("Failed to open file %s: %s\n",
5919                            fcpu, strerror(error));
5920                 return -error;
5921         }
5922         len = read(fd, buf, sizeof(buf));
5923         close(fd);
5924         if (len <= 0) {
5925                 error = len ? errno : EINVAL;
5926                 pr_warning("Failed to read # of possible cpus from %s: %s\n",
5927                            fcpu, strerror(error));
5928                 return -error;
5929         }
5930         if (len == sizeof(buf)) {
5931                 pr_warning("File %s size overflow\n", fcpu);
5932                 return -EOVERFLOW;
5933         }
5934         buf[len] = '\0';
5935
5936         for (ir = 0, tmp_cpus = 0; ir <= len; ir++) {
5937                 /* Each sub string separated by ',' has format \d+-\d+ or \d+ */
5938                 if (buf[ir] == ',' || buf[ir] == '\0') {
5939                         buf[ir] = '\0';
5940                         n = sscanf(&buf[il], "%u-%u", &start, &end);
5941                         if (n <= 0) {
5942                                 pr_warning("Failed to get # CPUs from %s\n",
5943                                            &buf[il]);
5944                                 return -EINVAL;
5945                         } else if (n == 1) {
5946                                 end = start;
5947                         }
5948                         tmp_cpus += end - start + 1;
5949                         il = ir + 1;
5950                 }
5951         }
5952         if (tmp_cpus <= 0) {
5953                 pr_warning("Invalid #CPUs %d from %s\n", tmp_cpus, fcpu);
5954                 return -EINVAL;
5955         }
5956
5957         WRITE_ONCE(cpus, tmp_cpus);
5958         return tmp_cpus;
5959 }