tools/lib/bpf/libbpf.c

   1 /*
   2  * Common eBPF ELF object loading operations.
   3  *
   4  * Copyright (C) 2013-2015 Alexei Starovoitov <ast@kernel.org>
   5  * Copyright (C) 2015 Wang Nan <wangnan0@huawei.com>
   6  * Copyright (C) 2015 Huawei Inc.
   7  *
   8  * This program is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License as published by the Free Software Foundation;
  11  * version 2.1 of the License (not later!)
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with this program; if not,  see <http://www.gnu.org/licenses>
  20  */
  21
  22 #include <stdlib.h>
  23 #include <stdio.h>
  24 #include <stdarg.h>
  25 #include <inttypes.h>
  26 #include <string.h>
  27 #include <unistd.h>
  28 #include <fcntl.h>
  29 #include <errno.h>
  30 #include <asm/unistd.h>
  31 #include <linux/kernel.h>
  32 #include <linux/bpf.h>
  33 #include <linux/list.h>
  34 #include <libelf.h>
  35 #include <gelf.h>
  36
  37 #include "libbpf.h"
  38 #include "bpf.h"
  39
  40 #ifndef EM_BPF
  41 #define EM_BPF 247
  42 #endif
  43
  44 #define __printf(a, b)  __attribute__((format(printf, a, b)))
  45
  46 __printf(1, 2)
  47 static int __base_pr(const char *format, ...)
  48 {
  49         va_list args;
  50         int err;
  51
  52         va_start(args, format);
  53         err = vfprintf(stderr, format, args);
  54         va_end(args);
  55         return err;
  56 }
  57
  58 static __printf(1, 2) libbpf_print_fn_t __pr_warning = __base_pr;
  59 static __printf(1, 2) libbpf_print_fn_t __pr_info = __base_pr;
  60 static __printf(1, 2) libbpf_print_fn_t __pr_debug;
  61
  62 #define __pr(func, fmt, ...)    \
  63 do {                            \
  64         if ((func))             \
  65                 (func)("libbpf: " fmt, ##__VA_ARGS__); \
  66 } while (0)
  67
  68 #define pr_warning(fmt, ...)    __pr(__pr_warning, fmt, ##__VA_ARGS__)
  69 #define pr_info(fmt, ...)       __pr(__pr_info, fmt, ##__VA_ARGS__)
  70 #define pr_debug(fmt, ...)      __pr(__pr_debug, fmt, ##__VA_ARGS__)
  71
  72 void libbpf_set_print(libbpf_print_fn_t warn,
  73                       libbpf_print_fn_t info,
  74                       libbpf_print_fn_t debug)
  75 {
  76         __pr_warning = warn;
  77         __pr_info = info;
  78         __pr_debug = debug;
  79 }
  80
  81 #define STRERR_BUFSIZE  128
  82
  83 #define ERRNO_OFFSET(e)         ((e) - __LIBBPF_ERRNO__START)
  84 #define ERRCODE_OFFSET(c)       ERRNO_OFFSET(LIBBPF_ERRNO__##c)
  85 #define NR_ERRNO        (__LIBBPF_ERRNO__END - __LIBBPF_ERRNO__START)
  86
  87 static const char *libbpf_strerror_table[NR_ERRNO] = {
  88         [ERRCODE_OFFSET(LIBELF)]        = "Something wrong in libelf",
  89         [ERRCODE_OFFSET(FORMAT)]        = "BPF object format invalid",
  90         [ERRCODE_OFFSET(KVERSION)]      = "'version' section incorrect or lost",
  91         [ERRCODE_OFFSET(ENDIAN)]        = "Endian mismatch",
  92         [ERRCODE_OFFSET(INTERNAL)]      = "Internal error in libbpf",
  93         [ERRCODE_OFFSET(RELOC)]         = "Relocation failed",
  94         [ERRCODE_OFFSET(VERIFY)]        = "Kernel verifier blocks program loading",
  95         [ERRCODE_OFFSET(PROG2BIG)]      = "Program too big",
  96         [ERRCODE_OFFSET(KVER)]          = "Incorrect kernel version",
  97         [ERRCODE_OFFSET(PROGTYPE)]      = "Kernel doesn't support this program type",
  98 };
  99
 100 int libbpf_strerror(int err, char *buf, size_t size)
 101 {
 102         if (!buf || !size)
 103                 return -1;
 104
 105         err = err > 0 ? err : -err;
 106
 107         if (err < __LIBBPF_ERRNO__START) {
 108                 int ret;
 109
 110                 ret = strerror_r(err, buf, size);
 111                 buf[size - 1] = '\0';
 112                 return ret;
 113         }
 114
 115         if (err < __LIBBPF_ERRNO__END) {
 116                 const char *msg;
 117
 118                 msg = libbpf_strerror_table[ERRNO_OFFSET(err)];
 119                 snprintf(buf, size, "%s", msg);
 120                 buf[size - 1] = '\0';
 121                 return 0;
 122         }
 123
 124         snprintf(buf, size, "Unknown libbpf error %d", err);
 125         buf[size - 1] = '\0';
 126         return -1;
 127 }
 128
 129 #define CHECK_ERR(action, err, out) do {        \
 130         err = action;                   \
 131         if (err)                        \
 132                 goto out;               \
 133 } while(0)
 134
 135
 136 /* Copied from tools/perf/util/util.h */
 137 #ifndef zfree
 138 # define zfree(ptr) ({ free(*ptr); *ptr = NULL; })
 139 #endif
 140
 141 #ifndef zclose
 142 # define zclose(fd) ({                  \
 143         int ___err = 0;                 \
 144         if ((fd) >= 0)                  \
 145                 ___err = close((fd));   \
 146         fd = -1;                        \
 147         ___err; })
 148 #endif
 149
 150 #ifdef HAVE_LIBELF_MMAP_SUPPORT
 151 # define LIBBPF_ELF_C_READ_MMAP ELF_C_READ_MMAP
 152 #else
 153 # define LIBBPF_ELF_C_READ_MMAP ELF_C_READ
 154 #endif
 155
 156 /*
 157  * bpf_prog should be a better name but it has been used in
 158  * linux/filter.h.
 159  */
 160 struct bpf_program {
 161         /* Index in elf obj file, for relocation use. */
 162         int idx;
 163         char *section_name;
 164         struct bpf_insn *insns;
 165         size_t insns_cnt;
 166         enum bpf_prog_type type;
 167
 168         struct {
 169                 int insn_idx;
 170                 int map_idx;
 171         } *reloc_desc;
 172         int nr_reloc;
 173
 174         struct {
 175                 int nr;
 176                 int *fds;
 177         } instances;
 178         bpf_program_prep_t preprocessor;
 179
 180         struct bpf_object *obj;
 181         void *priv;
 182         bpf_program_clear_priv_t clear_priv;
 183 };
 184
 185 struct bpf_map {
 186         int fd;
 187         char *name;
 188         size_t offset;
 189         struct bpf_map_def def;
 190         void *priv;
 191         bpf_map_clear_priv_t clear_priv;
 192 };
 193
 194 static LIST_HEAD(bpf_objects_list);
 195
 196 struct bpf_object {
 197         char license[64];
 198         u32 kern_version;
 199
 200         struct bpf_program *programs;
 201         size_t nr_programs;
 202         struct bpf_map *maps;
 203         size_t nr_maps;
 204
 205         bool loaded;
 206
 207         /*
 208          * Information when doing elf related work. Only valid if fd
 209          * is valid.
 210          */
 211         struct {
 212                 int fd;
 213                 void *obj_buf;
 214                 size_t obj_buf_sz;
 215                 Elf *elf;
 216                 GElf_Ehdr ehdr;
 217                 Elf_Data *symbols;
 218                 size_t strtabidx;
 219                 struct {
 220                         GElf_Shdr shdr;
 221                         Elf_Data *data;
 222                 } *reloc;
 223                 int nr_reloc;
 224                 int maps_shndx;
 225         } efile;
 226         /*
 227          * All loaded bpf_object is linked in a list, which is
 228          * hidden to caller. bpf_objects__<func> handlers deal with
 229          * all objects.
 230          */
 231         struct list_head list;
 232
 233         void *priv;
 234         bpf_object_clear_priv_t clear_priv;
 235
 236         char path[];
 237 };
 238 #define obj_elf_valid(o)        ((o)->efile.elf)
 239
 240 static void bpf_program__unload(struct bpf_program *prog)
 241 {
 242         int i;
 243
 244         if (!prog)
 245                 return;
 246
 247         /*
 248          * If the object is opened but the program was never loaded,
 249          * it is possible that prog->instances.nr == -1.
 250          */
 251         if (prog->instances.nr > 0) {
 252                 for (i = 0; i < prog->instances.nr; i++)
 253                         zclose(prog->instances.fds[i]);
 254         } else if (prog->instances.nr != -1) {
 255                 pr_warning("Internal error: instances.nr is %d\n",
 256                            prog->instances.nr);
 257         }
 258
 259         prog->instances.nr = -1;
 260         zfree(&prog->instances.fds);
 261 }
 262
 263 static void bpf_program__exit(struct bpf_program *prog)
 264 {
 265         if (!prog)
 266                 return;
 267
 268         if (prog->clear_priv)
 269                 prog->clear_priv(prog, prog->priv);
 270
 271         prog->priv = NULL;
 272         prog->clear_priv = NULL;
 273
 274         bpf_program__unload(prog);
 275         zfree(&prog->section_name);
 276         zfree(&prog->insns);
 277         zfree(&prog->reloc_desc);
 278
 279         prog->nr_reloc = 0;
 280         prog->insns_cnt = 0;
 281         prog->idx = -1;
 282 }
 283
 284 static int
 285 bpf_program__init(void *data, size_t size, char *name, int idx,
 286                     struct bpf_program *prog)
 287 {
 288         if (size < sizeof(struct bpf_insn)) {
 289                 pr_warning("corrupted section '%s'\n", name);
 290                 return -EINVAL;
 291         }
 292
 293         bzero(prog, sizeof(*prog));
 294
 295         prog->section_name = strdup(name);
 296         if (!prog->section_name) {
 297                 pr_warning("failed to alloc name for prog %s\n",
 298                            name);
 299                 goto errout;
 300         }
 301
 302         prog->insns = malloc(size);
 303         if (!prog->insns) {
 304                 pr_warning("failed to alloc insns for %s\n", name);
 305                 goto errout;
 306         }
 307         prog->insns_cnt = size / sizeof(struct bpf_insn);
 308         memcpy(prog->insns, data,
 309                prog->insns_cnt * sizeof(struct bpf_insn));
 310         prog->idx = idx;
 311         prog->instances.fds = NULL;
 312         prog->instances.nr = -1;
 313         prog->type = BPF_PROG_TYPE_KPROBE;
 314
 315         return 0;
 316 errout:
 317         bpf_program__exit(prog);
 318         return -ENOMEM;
 319 }
 320
 321 static int
 322 bpf_object__add_program(struct bpf_object *obj, void *data, size_t size,
 323                         char *name, int idx)
 324 {
 325         struct bpf_program prog, *progs;
 326         int nr_progs, err;
 327
 328         err = bpf_program__init(data, size, name, idx, &prog);
 329         if (err)
 330                 return err;
 331
 332         progs = obj->programs;
 333         nr_progs = obj->nr_programs;
 334
 335         progs = realloc(progs, sizeof(progs[0]) * (nr_progs + 1));
 336         if (!progs) {
 337                 /*
 338                  * In this case the original obj->programs
 339                  * is still valid, so don't need special treat for
 340                  * bpf_close_object().
 341                  */
 342                 pr_warning("failed to alloc a new program '%s'\n",
 343                            name);
 344                 bpf_program__exit(&prog);
 345                 return -ENOMEM;
 346         }
 347
 348         pr_debug("found program %s\n", prog.section_name);
 349         obj->programs = progs;
 350         obj->nr_programs = nr_progs + 1;
 351         prog.obj = obj;
 352         progs[nr_progs] = prog;
 353         return 0;
 354 }
 355
 356 static struct bpf_object *bpf_object__new(const char *path,
 357                                           void *obj_buf,
 358                                           size_t obj_buf_sz)
 359 {
 360         struct bpf_object *obj;
 361
 362         obj = calloc(1, sizeof(struct bpf_object) + strlen(path) + 1);
 363         if (!obj) {
 364                 pr_warning("alloc memory failed for %s\n", path);
 365                 return ERR_PTR(-ENOMEM);
 366         }
 367
 368         strcpy(obj->path, path);
 369         obj->efile.fd = -1;
 370
 371         /*
 372          * Caller of this function should also calls
 373          * bpf_object__elf_finish() after data collection to return
 374          * obj_buf to user. If not, we should duplicate the buffer to
 375          * avoid user freeing them before elf finish.
 376          */
 377         obj->efile.obj_buf = obj_buf;
 378         obj->efile.obj_buf_sz = obj_buf_sz;
 379         obj->efile.maps_shndx = -1;
 380
 381         obj->loaded = false;
 382
 383         INIT_LIST_HEAD(&obj->list);
 384         list_add(&obj->list, &bpf_objects_list);
 385         return obj;
 386 }
 387
 388 static void bpf_object__elf_finish(struct bpf_object *obj)
 389 {
 390         if (!obj_elf_valid(obj))
 391                 return;
 392
 393         if (obj->efile.elf) {
 394                 elf_end(obj->efile.elf);
 395                 obj->efile.elf = NULL;
 396         }
 397         obj->efile.symbols = NULL;
 398
 399         zfree(&obj->efile.reloc);
 400         obj->efile.nr_reloc = 0;
 401         zclose(obj->efile.fd);
 402         obj->efile.obj_buf = NULL;
 403         obj->efile.obj_buf_sz = 0;
 404 }
 405
 406 static int bpf_object__elf_init(struct bpf_object *obj)
 407 {
 408         int err = 0;
 409         GElf_Ehdr *ep;
 410
 411         if (obj_elf_valid(obj)) {
 412                 pr_warning("elf init: internal error\n");
 413                 return -LIBBPF_ERRNO__LIBELF;
 414         }
 415
 416         if (obj->efile.obj_buf_sz > 0) {
 417                 /*
 418                  * obj_buf should have been validated by
 419                  * bpf_object__open_buffer().
 420                  */
 421                 obj->efile.elf = elf_memory(obj->efile.obj_buf,
 422                                             obj->efile.obj_buf_sz);
 423         } else {
 424                 obj->efile.fd = open(obj->path, O_RDONLY);
 425                 if (obj->efile.fd < 0) {
 426                         pr_warning("failed to open %s: %s\n", obj->path,
 427                                         strerror(errno));
 428                         return -errno;
 429                 }
 430
 431                 obj->efile.elf = elf_begin(obj->efile.fd,
 432                                 LIBBPF_ELF_C_READ_MMAP,
 433                                 NULL);
 434         }
 435
 436         if (!obj->efile.elf) {
 437                 pr_warning("failed to open %s as ELF file\n",
 438                                 obj->path);
 439                 err = -LIBBPF_ERRNO__LIBELF;
 440                 goto errout;
 441         }
 442
 443         if (!gelf_getehdr(obj->efile.elf, &obj->efile.ehdr)) {
 444                 pr_warning("failed to get EHDR from %s\n",
 445                                 obj->path);
 446                 err = -LIBBPF_ERRNO__FORMAT;
 447                 goto errout;
 448         }
 449         ep = &obj->efile.ehdr;
 450
 451         /* Old LLVM set e_machine to EM_NONE */
 452         if ((ep->e_type != ET_REL) || (ep->e_machine && (ep->e_machine != EM_BPF))) {
 453                 pr_warning("%s is not an eBPF object file\n",
 454                         obj->path);
 455                 err = -LIBBPF_ERRNO__FORMAT;
 456                 goto errout;
 457         }
 458
 459         return 0;
 460 errout:
 461         bpf_object__elf_finish(obj);
 462         return err;
 463 }
 464
 465 static int
 466 bpf_object__check_endianness(struct bpf_object *obj)
 467 {
 468         static unsigned int const endian = 1;
 469
 470         switch (obj->efile.ehdr.e_ident[EI_DATA]) {
 471         case ELFDATA2LSB:
 472                 /* We are big endian, BPF obj is little endian. */
 473                 if (*(unsigned char const *)&endian != 1)
 474                         goto mismatch;
 475                 break;
 476
 477         case ELFDATA2MSB:
 478                 /* We are little endian, BPF obj is big endian. */
 479                 if (*(unsigned char const *)&endian != 0)
 480                         goto mismatch;
 481                 break;
 482         default:
 483                 return -LIBBPF_ERRNO__ENDIAN;
 484         }
 485
 486         return 0;
 487
 488 mismatch:
 489         pr_warning("Error: endianness mismatch.\n");
 490         return -LIBBPF_ERRNO__ENDIAN;
 491 }
 492
 493 static int
 494 bpf_object__init_license(struct bpf_object *obj,
 495                          void *data, size_t size)
 496 {
 497         memcpy(obj->license, data,
 498                min(size, sizeof(obj->license) - 1));
 499         pr_debug("license of %s is %s\n", obj->path, obj->license);
 500         return 0;
 501 }
 502
 503 static int
 504 bpf_object__init_kversion(struct bpf_object *obj,
 505                           void *data, size_t size)
 506 {
 507         u32 kver;
 508
 509         if (size != sizeof(kver)) {
 510                 pr_warning("invalid kver section in %s\n", obj->path);
 511                 return -LIBBPF_ERRNO__FORMAT;
 512         }
 513         memcpy(&kver, data, sizeof(kver));
 514         obj->kern_version = kver;
 515         pr_debug("kernel version of %s is %x\n", obj->path,
 516                  obj->kern_version);
 517         return 0;
 518 }
 519
 520 static int
 521 bpf_object__validate_maps(struct bpf_object *obj)
 522 {
 523         int i;
 524
 525         /*
 526          * If there's only 1 map, the only error case should have been
 527          * catched in bpf_object__init_maps().
 528          */
 529         if (!obj->maps || !obj->nr_maps || (obj->nr_maps == 1))
 530                 return 0;
 531
 532         for (i = 1; i < obj->nr_maps; i++) {
 533                 const struct bpf_map *a = &obj->maps[i - 1];
 534                 const struct bpf_map *b = &obj->maps[i];
 535
 536                 if (b->offset - a->offset < sizeof(struct bpf_map_def)) {
 537                         pr_warning("corrupted map section in %s: map \"%s\" too small\n",
 538                                    obj->path, a->name);
 539                         return -EINVAL;
 540                 }
 541         }
 542         return 0;
 543 }
 544
 545 static int compare_bpf_map(const void *_a, const void *_b)
 546 {
 547         const struct bpf_map *a = _a;
 548         const struct bpf_map *b = _b;
 549
 550         return a->offset - b->offset;
 551 }
 552
 553 static int
 554 bpf_object__init_maps(struct bpf_object *obj)
 555 {
 556         int i, map_idx, nr_maps = 0;
 557         Elf_Scn *scn;
 558         Elf_Data *data;
 559         Elf_Data *symbols = obj->efile.symbols;
 560
 561         if (obj->efile.maps_shndx < 0)
 562                 return -EINVAL;
 563         if (!symbols)
 564                 return -EINVAL;
 565
 566         scn = elf_getscn(obj->efile.elf, obj->efile.maps_shndx);
 567         if (scn)
 568                 data = elf_getdata(scn, NULL);
 569         if (!scn || !data) {
 570                 pr_warning("failed to get Elf_Data from map section %d\n",
 571                            obj->efile.maps_shndx);
 572                 return -EINVAL;
 573         }
 574
 575         /*
 576          * Count number of maps. Each map has a name.
 577          * Array of maps is not supported: only the first element is
 578          * considered.
 579          *
 580          * TODO: Detect array of map and report error.
 581          */
 582         for (i = 0; i < symbols->d_size / sizeof(GElf_Sym); i++) {
 583                 GElf_Sym sym;
 584
 585                 if (!gelf_getsym(symbols, i, &sym))
 586                         continue;
 587                 if (sym.st_shndx != obj->efile.maps_shndx)
 588                         continue;
 589                 nr_maps++;
 590         }
 591
 592         /* Alloc obj->maps and fill nr_maps. */
 593         pr_debug("maps in %s: %d maps in %zd bytes\n", obj->path,
 594                  nr_maps, data->d_size);
 595
 596         if (!nr_maps)
 597                 return 0;
 598
 599         obj->maps = calloc(nr_maps, sizeof(obj->maps[0]));
 600         if (!obj->maps) {
 601                 pr_warning("alloc maps for object failed\n");
 602                 return -ENOMEM;
 603         }
 604         obj->nr_maps = nr_maps;
 605
 606         /*
 607          * fill all fd with -1 so won't close incorrect
 608          * fd (fd=0 is stdin) when failure (zclose won't close
 609          * negative fd)).
 610          */
 611         for (i = 0; i < nr_maps; i++)
 612                 obj->maps[i].fd = -1;
 613
 614         /*
 615          * Fill obj->maps using data in "maps" section.
 616          */
 617         for (i = 0, map_idx = 0; i < symbols->d_size / sizeof(GElf_Sym); i++) {
 618                 GElf_Sym sym;
 619                 const char *map_name;
 620                 struct bpf_map_def *def;
 621
 622                 if (!gelf_getsym(symbols, i, &sym))
 623                         continue;
 624                 if (sym.st_shndx != obj->efile.maps_shndx)
 625                         continue;
 626
 627                 map_name = elf_strptr(obj->efile.elf,
 628                                       obj->efile.strtabidx,
 629                                       sym.st_name);
 630                 obj->maps[map_idx].offset = sym.st_value;
 631                 if (sym.st_value + sizeof(struct bpf_map_def) > data->d_size) {
 632                         pr_warning("corrupted maps section in %s: last map \"%s\" too small\n",
 633                                    obj->path, map_name);
 634                         return -EINVAL;
 635                 }
 636
 637                 obj->maps[map_idx].name = strdup(map_name);
 638                 if (!obj->maps[map_idx].name) {
 639                         pr_warning("failed to alloc map name\n");
 640                         return -ENOMEM;
 641                 }
 642                 pr_debug("map %d is \"%s\"\n", map_idx,
 643                          obj->maps[map_idx].name);
 644                 def = (struct bpf_map_def *)(data->d_buf + sym.st_value);
 645                 obj->maps[map_idx].def = *def;
 646                 map_idx++;
 647         }
 648
 649         qsort(obj->maps, obj->nr_maps, sizeof(obj->maps[0]), compare_bpf_map);
 650         return bpf_object__validate_maps(obj);
 651 }
 652
 653 static int bpf_object__elf_collect(struct bpf_object *obj)
 654 {
 655         Elf *elf = obj->efile.elf;
 656         GElf_Ehdr *ep = &obj->efile.ehdr;
 657         Elf_Scn *scn = NULL;
 658         int idx = 0, err = 0;
 659
 660         /* Elf is corrupted/truncated, avoid calling elf_strptr. */
 661         if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL)) {
 662                 pr_warning("failed to get e_shstrndx from %s\n",
 663                            obj->path);
 664                 return -LIBBPF_ERRNO__FORMAT;
 665         }
 666
 667         while ((scn = elf_nextscn(elf, scn)) != NULL) {
 668                 char *name;
 669                 GElf_Shdr sh;
 670                 Elf_Data *data;
 671
 672                 idx++;
 673                 if (gelf_getshdr(scn, &sh) != &sh) {
 674                         pr_warning("failed to get section header from %s\n",
 675                                    obj->path);
 676                         err = -LIBBPF_ERRNO__FORMAT;
 677                         goto out;
 678                 }
 679
 680                 name = elf_strptr(elf, ep->e_shstrndx, sh.sh_name);
 681                 if (!name) {
 682                         pr_warning("failed to get section name from %s\n",
 683                                    obj->path);
 684                         err = -LIBBPF_ERRNO__FORMAT;
 685                         goto out;
 686                 }
 687
 688                 data = elf_getdata(scn, 0);
 689                 if (!data) {
 690                         pr_warning("failed to get section data from %s(%s)\n",
 691                                    name, obj->path);
 692                         err = -LIBBPF_ERRNO__FORMAT;
 693                         goto out;
 694                 }
 695                 pr_debug("section %s, size %ld, link %d, flags %lx, type=%d\n",
 696                          name, (unsigned long)data->d_size,
 697                          (int)sh.sh_link, (unsigned long)sh.sh_flags,
 698                          (int)sh.sh_type);
 699
 700                 if (strcmp(name, "license") == 0)
 701                         err = bpf_object__init_license(obj,
 702                                                        data->d_buf,
 703                                                        data->d_size);
 704                 else if (strcmp(name, "version") == 0)
 705                         err = bpf_object__init_kversion(obj,
 706                                                         data->d_buf,
 707                                                         data->d_size);
 708                 else if (strcmp(name, "maps") == 0)
 709                         obj->efile.maps_shndx = idx;
 710                 else if (sh.sh_type == SHT_SYMTAB) {
 711                         if (obj->efile.symbols) {
 712                                 pr_warning("bpf: multiple SYMTAB in %s\n",
 713                                            obj->path);
 714                                 err = -LIBBPF_ERRNO__FORMAT;
 715                         } else {
 716                                 obj->efile.symbols = data;
 717                                 obj->efile.strtabidx = sh.sh_link;
 718                         }
 719                 } else if ((sh.sh_type == SHT_PROGBITS) &&
 720                            (sh.sh_flags & SHF_EXECINSTR) &&
 721                            (data->d_size > 0)) {
 722                         err = bpf_object__add_program(obj, data->d_buf,
 723                                                       data->d_size, name, idx);
 724                         if (err) {
 725                                 char errmsg[STRERR_BUFSIZE];
 726
 727                                 strerror_r(-err, errmsg, sizeof(errmsg));
 728                                 pr_warning("failed to alloc program %s (%s): %s",
 729                                            name, obj->path, errmsg);
 730                         }
 731                 } else if (sh.sh_type == SHT_REL) {
 732                         void *reloc = obj->efile.reloc;
 733                         int nr_reloc = obj->efile.nr_reloc + 1;
 734
 735                         reloc = realloc(reloc,
 736                                         sizeof(*obj->efile.reloc) * nr_reloc);
 737                         if (!reloc) {
 738                                 pr_warning("realloc failed\n");
 739                                 err = -ENOMEM;
 740                         } else {
 741                                 int n = nr_reloc - 1;
 742
 743                                 obj->efile.reloc = reloc;
 744                                 obj->efile.nr_reloc = nr_reloc;
 745
 746                                 obj->efile.reloc[n].shdr = sh;
 747                                 obj->efile.reloc[n].data = data;
 748                         }
 749                 }
 750                 if (err)
 751                         goto out;
 752         }
 753
 754         if (!obj->efile.strtabidx || obj->efile.strtabidx >= idx) {
 755                 pr_warning("Corrupted ELF file: index of strtab invalid\n");
 756                 return LIBBPF_ERRNO__FORMAT;
 757         }
 758         if (obj->efile.maps_shndx >= 0)
 759                 err = bpf_object__init_maps(obj);
 760 out:
 761         return err;
 762 }
 763
 764 static struct bpf_program *
 765 bpf_object__find_prog_by_idx(struct bpf_object *obj, int idx)
 766 {
 767         struct bpf_program *prog;
 768         size_t i;
 769
 770         for (i = 0; i < obj->nr_programs; i++) {
 771                 prog = &obj->programs[i];
 772                 if (prog->idx == idx)
 773                         return prog;
 774         }
 775         return NULL;
 776 }
 777
 778 static int
 779 bpf_program__collect_reloc(struct bpf_program *prog,
 780                            size_t nr_maps, GElf_Shdr *shdr,
 781                            Elf_Data *data, Elf_Data *symbols,
 782                            int maps_shndx, struct bpf_map *maps)
 783 {
 784         int i, nrels;
 785
 786         pr_debug("collecting relocating info for: '%s'\n",
 787                  prog->section_name);
 788         nrels = shdr->sh_size / shdr->sh_entsize;
 789
 790         prog->reloc_desc = malloc(sizeof(*prog->reloc_desc) * nrels);
 791         if (!prog->reloc_desc) {
 792                 pr_warning("failed to alloc memory in relocation\n");
 793                 return -ENOMEM;
 794         }
 795         prog->nr_reloc = nrels;
 796
 797         for (i = 0; i < nrels; i++) {
 798                 GElf_Sym sym;
 799                 GElf_Rel rel;
 800                 unsigned int insn_idx;
 801                 struct bpf_insn *insns = prog->insns;
 802                 size_t map_idx;
 803
 804                 if (!gelf_getrel(data, i, &rel)) {
 805                         pr_warning("relocation: failed to get %d reloc\n", i);
 806                         return -LIBBPF_ERRNO__FORMAT;
 807                 }
 808
 809                 if (!gelf_getsym(symbols,
 810                                  GELF_R_SYM(rel.r_info),
 811                                  &sym)) {
 812                         pr_warning("relocation: symbol %"PRIx64" not found\n",
 813                                    GELF_R_SYM(rel.r_info));
 814                         return -LIBBPF_ERRNO__FORMAT;
 815                 }
 816
 817                 if (sym.st_shndx != maps_shndx) {
 818                         pr_warning("Program '%s' contains non-map related relo data pointing to section %u\n",
 819                                    prog->section_name, sym.st_shndx);
 820                         return -LIBBPF_ERRNO__RELOC;
 821                 }
 822
 823                 insn_idx = rel.r_offset / sizeof(struct bpf_insn);
 824                 pr_debug("relocation: insn_idx=%u\n", insn_idx);
 825
 826                 if (insns[insn_idx].code != (BPF_LD | BPF_IMM | BPF_DW)) {
 827                         pr_warning("bpf: relocation: invalid relo for insns[%d].code 0x%x\n",
 828                                    insn_idx, insns[insn_idx].code);
 829                         return -LIBBPF_ERRNO__RELOC;
 830                 }
 831
 832                 /* TODO: 'maps' is sorted. We can use bsearch to make it faster. */
 833                 for (map_idx = 0; map_idx < nr_maps; map_idx++) {
 834                         if (maps[map_idx].offset == sym.st_value) {
 835                                 pr_debug("relocation: find map %zd (%s) for insn %u\n",
 836                                          map_idx, maps[map_idx].name, insn_idx);
 837                                 break;
 838                         }
 839                 }
 840
 841                 if (map_idx >= nr_maps) {
 842                         pr_warning("bpf relocation: map_idx %d large than %d\n",
 843                                    (int)map_idx, (int)nr_maps - 1);
 844                         return -LIBBPF_ERRNO__RELOC;
 845                 }
 846
 847                 prog->reloc_desc[i].insn_idx = insn_idx;
 848                 prog->reloc_desc[i].map_idx = map_idx;
 849         }
 850         return 0;
 851 }
 852
 853 static int
 854 bpf_object__create_maps(struct bpf_object *obj)
 855 {
 856         unsigned int i;
 857
 858         for (i = 0; i < obj->nr_maps; i++) {
 859                 struct bpf_map_def *def = &obj->maps[i].def;
 860                 int *pfd = &obj->maps[i].fd;
 861
 862                 *pfd = bpf_create_map(def->type,
 863                                       def->key_size,
 864                                       def->value_size,
 865                                       def->max_entries,
 866                                       0);
 867                 if (*pfd < 0) {
 868                         size_t j;
 869                         int err = *pfd;
 870
 871                         pr_warning("failed to create map: %s\n",
 872                                    strerror(errno));
 873                         for (j = 0; j < i; j++)
 874                                 zclose(obj->maps[j].fd);
 875                         return err;
 876                 }
 877                 pr_debug("create map %s: fd=%d\n", obj->maps[i].name, *pfd);
 878         }
 879
 880         return 0;
 881 }
 882
 883 static int
 884 bpf_program__relocate(struct bpf_program *prog, struct bpf_object *obj)
 885 {
 886         int i;
 887
 888         if (!prog || !prog->reloc_desc)
 889                 return 0;
 890
 891         for (i = 0; i < prog->nr_reloc; i++) {
 892                 int insn_idx, map_idx;
 893                 struct bpf_insn *insns = prog->insns;
 894
 895                 insn_idx = prog->reloc_desc[i].insn_idx;
 896                 map_idx = prog->reloc_desc[i].map_idx;
 897
 898                 if (insn_idx >= (int)prog->insns_cnt) {
 899                         pr_warning("relocation out of range: '%s'\n",
 900                                    prog->section_name);
 901                         return -LIBBPF_ERRNO__RELOC;
 902                 }
 903                 insns[insn_idx].src_reg = BPF_PSEUDO_MAP_FD;
 904                 insns[insn_idx].imm = obj->maps[map_idx].fd;
 905         }
 906
 907         zfree(&prog->reloc_desc);
 908         prog->nr_reloc = 0;
 909         return 0;
 910 }
 911
 912
 913 static int
 914 bpf_object__relocate(struct bpf_object *obj)
 915 {
 916         struct bpf_program *prog;
 917         size_t i;
 918         int err;
 919
 920         for (i = 0; i < obj->nr_programs; i++) {
 921                 prog = &obj->programs[i];
 922
 923                 err = bpf_program__relocate(prog, obj);
 924                 if (err) {
 925                         pr_warning("failed to relocate '%s'\n",
 926                                    prog->section_name);
 927                         return err;
 928                 }
 929         }
 930         return 0;
 931 }
 932
 933 static int bpf_object__collect_reloc(struct bpf_object *obj)
 934 {
 935         int i, err;
 936
 937         if (!obj_elf_valid(obj)) {
 938                 pr_warning("Internal error: elf object is closed\n");
 939                 return -LIBBPF_ERRNO__INTERNAL;
 940         }
 941
 942         for (i = 0; i < obj->efile.nr_reloc; i++) {
 943                 GElf_Shdr *shdr = &obj->efile.reloc[i].shdr;
 944                 Elf_Data *data = obj->efile.reloc[i].data;
 945                 int idx = shdr->sh_info;
 946                 struct bpf_program *prog;
 947                 size_t nr_maps = obj->nr_maps;
 948
 949                 if (shdr->sh_type != SHT_REL) {
 950                         pr_warning("internal error at %d\n", __LINE__);
 951                         return -LIBBPF_ERRNO__INTERNAL;
 952                 }
 953
 954                 prog = bpf_object__find_prog_by_idx(obj, idx);
 955                 if (!prog) {
 956                         pr_warning("relocation failed: no %d section\n",
 957                                    idx);
 958                         return -LIBBPF_ERRNO__RELOC;
 959                 }
 960
 961                 err = bpf_program__collect_reloc(prog, nr_maps,
 962                                                  shdr, data,
 963                                                  obj->efile.symbols,
 964                                                  obj->efile.maps_shndx,
 965                                                  obj->maps);
 966                 if (err)
 967                         return err;
 968         }
 969         return 0;
 970 }
 971
 972 static int
 973 load_program(enum bpf_prog_type type, struct bpf_insn *insns,
 974              int insns_cnt, char *license, u32 kern_version, int *pfd)
 975 {
 976         int ret;
 977         char *log_buf;
 978
 979         if (!insns || !insns_cnt)
 980                 return -EINVAL;
 981
 982         log_buf = malloc(BPF_LOG_BUF_SIZE);
 983         if (!log_buf)
 984                 pr_warning("Alloc log buffer for bpf loader error, continue without log\n");
 985
 986         ret = bpf_load_program(type, insns, insns_cnt, license,
 987                                kern_version, log_buf, BPF_LOG_BUF_SIZE);
 988
 989         if (ret >= 0) {
 990                 *pfd = ret;
 991                 ret = 0;
 992                 goto out;
 993         }
 994
 995         ret = -LIBBPF_ERRNO__LOAD;
 996         pr_warning("load bpf program failed: %s\n", strerror(errno));
 997
 998         if (log_buf && log_buf[0] != '\0') {
 999                 ret = -LIBBPF_ERRNO__VERIFY;
1000                 pr_warning("-- BEGIN DUMP LOG ---\n");
1001                 pr_warning("\n%s\n", log_buf);
1002                 pr_warning("-- END LOG --\n");
1003         } else if (insns_cnt >= BPF_MAXINSNS) {
1004                 pr_warning("Program too large (%d insns), at most %d insns\n",
1005                            insns_cnt, BPF_MAXINSNS);
1006                 ret = -LIBBPF_ERRNO__PROG2BIG;
1007         } else {
1008                 /* Wrong program type? */
1009                 if (type != BPF_PROG_TYPE_KPROBE) {
1010                         int fd;
1011
1012                         fd = bpf_load_program(BPF_PROG_TYPE_KPROBE, insns,
1013                                               insns_cnt, license, kern_version,
1014                                               NULL, 0);
1015                         if (fd >= 0) {
1016                                 close(fd);
1017                                 ret = -LIBBPF_ERRNO__PROGTYPE;
1018                                 goto out;
1019                         }
1020                 }
1021
1022                 if (log_buf)
1023                         ret = -LIBBPF_ERRNO__KVER;
1024         }
1025
1026 out:
1027         free(log_buf);
1028         return ret;
1029 }
1030
1031 static int
1032 bpf_program__load(struct bpf_program *prog,
1033                   char *license, u32 kern_version)
1034 {
1035         int err = 0, fd, i;
1036
1037         if (prog->instances.nr < 0 || !prog->instances.fds) {
1038                 if (prog->preprocessor) {
1039                         pr_warning("Internal error: can't load program '%s'\n",
1040                                    prog->section_name);
1041                         return -LIBBPF_ERRNO__INTERNAL;
1042                 }
1043
1044                 prog->instances.fds = malloc(sizeof(int));
1045                 if (!prog->instances.fds) {
1046                         pr_warning("Not enough memory for BPF fds\n");
1047                         return -ENOMEM;
1048                 }
1049                 prog->instances.nr = 1;
1050                 prog->instances.fds[0] = -1;
1051         }
1052
1053         if (!prog->preprocessor) {
1054                 if (prog->instances.nr != 1) {
1055                         pr_warning("Program '%s' is inconsistent: nr(%d) != 1\n",
1056                                    prog->section_name, prog->instances.nr);
1057                 }
1058                 err = load_program(prog->type, prog->insns, prog->insns_cnt,
1059                                    license, kern_version, &fd);
1060                 if (!err)
1061                         prog->instances.fds[0] = fd;
1062                 goto out;
1063         }
1064
1065         for (i = 0; i < prog->instances.nr; i++) {
1066                 struct bpf_prog_prep_result result;
1067                 bpf_program_prep_t preprocessor = prog->preprocessor;
1068
1069                 bzero(&result, sizeof(result));
1070                 err = preprocessor(prog, i, prog->insns,
1071                                    prog->insns_cnt, &result);
1072                 if (err) {
1073                         pr_warning("Preprocessing the %dth instance of program '%s' failed\n",
1074                                    i, prog->section_name);
1075                         goto out;
1076                 }
1077
1078                 if (!result.new_insn_ptr || !result.new_insn_cnt) {
1079                         pr_debug("Skip loading the %dth instance of program '%s'\n",
1080                                  i, prog->section_name);
1081                         prog->instances.fds[i] = -1;
1082                         if (result.pfd)
1083                                 *result.pfd = -1;
1084                         continue;
1085                 }
1086
1087                 err = load_program(prog->type, result.new_insn_ptr,
1088                                    result.new_insn_cnt,
1089                                    license, kern_version, &fd);
1090
1091                 if (err) {
1092                         pr_warning("Loading the %dth instance of program '%s' failed\n",
1093                                         i, prog->section_name);
1094                         goto out;
1095                 }
1096
1097                 if (result.pfd)
1098                         *result.pfd = fd;
1099                 prog->instances.fds[i] = fd;
1100         }
1101 out:
1102         if (err)
1103                 pr_warning("failed to load program '%s'\n",
1104                            prog->section_name);
1105         zfree(&prog->insns);
1106         prog->insns_cnt = 0;
1107         return err;
1108 }
1109
1110 static int
1111 bpf_object__load_progs(struct bpf_object *obj)
1112 {
1113         size_t i;
1114         int err;
1115
1116         for (i = 0; i < obj->nr_programs; i++) {
1117                 err = bpf_program__load(&obj->programs[i],
1118                                         obj->license,
1119                                         obj->kern_version);
1120                 if (err)
1121                         return err;
1122         }
1123         return 0;
1124 }
1125
1126 static int bpf_object__validate(struct bpf_object *obj)
1127 {
1128         if (obj->kern_version == 0) {
1129                 pr_warning("%s doesn't provide kernel version\n",
1130                            obj->path);
1131                 return -LIBBPF_ERRNO__KVERSION;
1132         }
1133         return 0;
1134 }
1135
1136 static struct bpf_object *
1137 __bpf_object__open(const char *path, void *obj_buf, size_t obj_buf_sz)
1138 {
1139         struct bpf_object *obj;
1140         int err;
1141
1142         if (elf_version(EV_CURRENT) == EV_NONE) {
1143                 pr_warning("failed to init libelf for %s\n", path);
1144                 return ERR_PTR(-LIBBPF_ERRNO__LIBELF);
1145         }
1146
1147         obj = bpf_object__new(path, obj_buf, obj_buf_sz);
1148         if (IS_ERR(obj))
1149                 return obj;
1150
1151         CHECK_ERR(bpf_object__elf_init(obj), err, out);
1152         CHECK_ERR(bpf_object__check_endianness(obj), err, out);
1153         CHECK_ERR(bpf_object__elf_collect(obj), err, out);
1154         CHECK_ERR(bpf_object__collect_reloc(obj), err, out);
1155         CHECK_ERR(bpf_object__validate(obj), err, out);
1156
1157         bpf_object__elf_finish(obj);
1158         return obj;
1159 out:
1160         bpf_object__close(obj);
1161         return ERR_PTR(err);
1162 }
1163
1164 struct bpf_object *bpf_object__open(const char *path)
1165 {
1166         /* param validation */
1167         if (!path)
1168                 return NULL;
1169
1170         pr_debug("loading %s\n", path);
1171
1172         return __bpf_object__open(path, NULL, 0);
1173 }
1174
1175 struct bpf_object *bpf_object__open_buffer(void *obj_buf,
1176                                            size_t obj_buf_sz,
1177                                            const char *name)
1178 {
1179         char tmp_name[64];
1180
1181         /* param validation */
1182         if (!obj_buf || obj_buf_sz <= 0)
1183                 return NULL;
1184
1185         if (!name) {
1186                 snprintf(tmp_name, sizeof(tmp_name), "%lx-%lx",
1187                          (unsigned long)obj_buf,
1188                          (unsigned long)obj_buf_sz);
1189                 tmp_name[sizeof(tmp_name) - 1] = '\0';
1190                 name = tmp_name;
1191         }
1192         pr_debug("loading object '%s' from buffer\n",
1193                  name);
1194
1195         return __bpf_object__open(name, obj_buf, obj_buf_sz);
1196 }
1197
1198 int bpf_object__unload(struct bpf_object *obj)
1199 {
1200         size_t i;
1201
1202         if (!obj)
1203                 return -EINVAL;
1204
1205         for (i = 0; i < obj->nr_maps; i++)
1206                 zclose(obj->maps[i].fd);
1207
1208         for (i = 0; i < obj->nr_programs; i++)
1209                 bpf_program__unload(&obj->programs[i]);
1210
1211         return 0;
1212 }
1213
1214 int bpf_object__load(struct bpf_object *obj)
1215 {
1216         int err;
1217
1218         if (!obj)
1219                 return -EINVAL;
1220
1221         if (obj->loaded) {
1222                 pr_warning("object should not be loaded twice\n");
1223                 return -EINVAL;
1224         }
1225
1226         obj->loaded = true;
1227
1228         CHECK_ERR(bpf_object__create_maps(obj), err, out);
1229         CHECK_ERR(bpf_object__relocate(obj), err, out);
1230         CHECK_ERR(bpf_object__load_progs(obj), err, out);
1231
1232         return 0;
1233 out:
1234         bpf_object__unload(obj);
1235         pr_warning("failed to load object '%s'\n", obj->path);
1236         return err;
1237 }
1238
1239 void bpf_object__close(struct bpf_object *obj)
1240 {
1241         size_t i;
1242
1243         if (!obj)
1244                 return;
1245
1246         if (obj->clear_priv)
1247                 obj->clear_priv(obj, obj->priv);
1248
1249         bpf_object__elf_finish(obj);
1250         bpf_object__unload(obj);
1251
1252         for (i = 0; i < obj->nr_maps; i++) {
1253                 zfree(&obj->maps[i].name);
1254                 if (obj->maps[i].clear_priv)
1255                         obj->maps[i].clear_priv(&obj->maps[i],
1256                                                 obj->maps[i].priv);
1257                 obj->maps[i].priv = NULL;
1258                 obj->maps[i].clear_priv = NULL;
1259         }
1260         zfree(&obj->maps);
1261         obj->nr_maps = 0;
1262
1263         if (obj->programs && obj->nr_programs) {
1264                 for (i = 0; i < obj->nr_programs; i++)
1265                         bpf_program__exit(&obj->programs[i]);
1266         }
1267         zfree(&obj->programs);
1268
1269         list_del(&obj->list);
1270         free(obj);
1271 }
1272
1273 struct bpf_object *
1274 bpf_object__next(struct bpf_object *prev)
1275 {
1276         struct bpf_object *next;
1277
1278         if (!prev)
1279                 next = list_first_entry(&bpf_objects_list,
1280                                         struct bpf_object,
1281                                         list);
1282         else
1283                 next = list_next_entry(prev, list);
1284
1285         /* Empty list is noticed here so don't need checking on entry. */
1286         if (&next->list == &bpf_objects_list)
1287                 return NULL;
1288
1289         return next;
1290 }
1291
1292 const char *bpf_object__name(struct bpf_object *obj)
1293 {
1294         return obj ? obj->path : ERR_PTR(-EINVAL);
1295 }
1296
1297 unsigned int bpf_object__kversion(struct bpf_object *obj)
1298 {
1299         return obj ? obj->kern_version : 0;
1300 }
1301
1302 int bpf_object__set_priv(struct bpf_object *obj, void *priv,
1303                          bpf_object_clear_priv_t clear_priv)
1304 {
1305         if (obj->priv && obj->clear_priv)
1306                 obj->clear_priv(obj, obj->priv);
1307
1308         obj->priv = priv;
1309         obj->clear_priv = clear_priv;
1310         return 0;
1311 }
1312
1313 void *bpf_object__priv(struct bpf_object *obj)
1314 {
1315         return obj ? obj->priv : ERR_PTR(-EINVAL);
1316 }
1317
1318 struct bpf_program *
1319 bpf_program__next(struct bpf_program *prev, struct bpf_object *obj)
1320 {
1321         size_t idx;
1322
1323         if (!obj->programs)
1324                 return NULL;
1325         /* First handler */
1326         if (prev == NULL)
1327                 return &obj->programs[0];
1328
1329         if (prev->obj != obj) {
1330                 pr_warning("error: program handler doesn't match object\n");
1331                 return NULL;
1332         }
1333
1334         idx = (prev - obj->programs) + 1;
1335         if (idx >= obj->nr_programs)
1336                 return NULL;
1337         return &obj->programs[idx];
1338 }
1339
1340 int bpf_program__set_priv(struct bpf_program *prog, void *priv,
1341                           bpf_program_clear_priv_t clear_priv)
1342 {
1343         if (prog->priv && prog->clear_priv)
1344                 prog->clear_priv(prog, prog->priv);
1345
1346         prog->priv = priv;
1347         prog->clear_priv = clear_priv;
1348         return 0;
1349 }
1350
1351 void *bpf_program__priv(struct bpf_program *prog)
1352 {
1353         return prog ? prog->priv : ERR_PTR(-EINVAL);
1354 }
1355
1356 const char *bpf_program__title(struct bpf_program *prog, bool needs_copy)
1357 {
1358         const char *title;
1359
1360         title = prog->section_name;
1361         if (needs_copy) {
1362                 title = strdup(title);
1363                 if (!title) {
1364                         pr_warning("failed to strdup program title\n");
1365                         return ERR_PTR(-ENOMEM);
1366                 }
1367         }
1368
1369         return title;
1370 }
1371
1372 int bpf_program__fd(struct bpf_program *prog)
1373 {
1374         return bpf_program__nth_fd(prog, 0);
1375 }
1376
1377 int bpf_program__set_prep(struct bpf_program *prog, int nr_instances,
1378                           bpf_program_prep_t prep)
1379 {
1380         int *instances_fds;
1381
1382         if (nr_instances <= 0 || !prep)
1383                 return -EINVAL;
1384
1385         if (prog->instances.nr > 0 || prog->instances.fds) {
1386                 pr_warning("Can't set pre-processor after loading\n");
1387                 return -EINVAL;
1388         }
1389
1390         instances_fds = malloc(sizeof(int) * nr_instances);
1391         if (!instances_fds) {
1392                 pr_warning("alloc memory failed for fds\n");
1393                 return -ENOMEM;
1394         }
1395
1396         /* fill all fd with -1 */
1397         memset(instances_fds, -1, sizeof(int) * nr_instances);
1398
1399         prog->instances.nr = nr_instances;
1400         prog->instances.fds = instances_fds;
1401         prog->preprocessor = prep;
1402         return 0;
1403 }
1404
1405 int bpf_program__nth_fd(struct bpf_program *prog, int n)
1406 {
1407         int fd;
1408
1409         if (n >= prog->instances.nr || n < 0) {
1410                 pr_warning("Can't get the %dth fd from program %s: only %d instances\n",
1411                            n, prog->section_name, prog->instances.nr);
1412                 return -EINVAL;
1413         }
1414
1415         fd = prog->instances.fds[n];
1416         if (fd < 0) {
1417                 pr_warning("%dth instance of program '%s' is invalid\n",
1418                            n, prog->section_name);
1419                 return -ENOENT;
1420         }
1421
1422         return fd;
1423 }
1424
1425 static void bpf_program__set_type(struct bpf_program *prog,
1426                                   enum bpf_prog_type type)
1427 {
1428         prog->type = type;
1429 }
1430
1431 static bool bpf_program__is_type(struct bpf_program *prog,
1432                                  enum bpf_prog_type type)
1433 {
1434         return prog ? (prog->type == type) : false;
1435 }
1436
1437 #define BPF_PROG_TYPE_FNS(NAME, TYPE)                   \
1438 int bpf_program__set_##NAME(struct bpf_program *prog)   \
1439 {                                                       \
1440         if (!prog)                                      \
1441                 return -EINVAL;                         \
1442         bpf_program__set_type(prog, TYPE);              \
1443         return 0;                                       \
1444 }                                                       \
1445                                                         \
1446 bool bpf_program__is_##NAME(struct bpf_program *prog)   \
1447 {                                                       \
1448         return bpf_program__is_type(prog, TYPE);        \
1449 }                                                       \
1450
1451 BPF_PROG_TYPE_FNS(socket_filter, BPF_PROG_TYPE_SOCKET_FILTER);
1452 BPF_PROG_TYPE_FNS(kprobe, BPF_PROG_TYPE_KPROBE);
1453 BPF_PROG_TYPE_FNS(sched_cls, BPF_PROG_TYPE_SCHED_CLS);
1454 BPF_PROG_TYPE_FNS(sched_act, BPF_PROG_TYPE_SCHED_ACT);
1455 BPF_PROG_TYPE_FNS(tracepoint, BPF_PROG_TYPE_TRACEPOINT);
1456 BPF_PROG_TYPE_FNS(xdp, BPF_PROG_TYPE_XDP);
1457 BPF_PROG_TYPE_FNS(perf_event, BPF_PROG_TYPE_PERF_EVENT);
1458
1459 int bpf_map__fd(struct bpf_map *map)
1460 {
1461         return map ? map->fd : -EINVAL;
1462 }
1463
1464 const struct bpf_map_def *bpf_map__def(struct bpf_map *map)
1465 {
1466         return map ? &map->def : ERR_PTR(-EINVAL);
1467 }
1468
1469 const char *bpf_map__name(struct bpf_map *map)
1470 {
1471         return map ? map->name : NULL;
1472 }
1473
1474 int bpf_map__set_priv(struct bpf_map *map, void *priv,
1475                      bpf_map_clear_priv_t clear_priv)
1476 {
1477         if (!map)
1478                 return -EINVAL;
1479
1480         if (map->priv) {
1481                 if (map->clear_priv)
1482                         map->clear_priv(map, map->priv);
1483         }
1484
1485         map->priv = priv;
1486         map->clear_priv = clear_priv;
1487         return 0;
1488 }
1489
1490 void *bpf_map__priv(struct bpf_map *map)
1491 {
1492         return map ? map->priv : ERR_PTR(-EINVAL);
1493 }
1494
1495 struct bpf_map *
1496 bpf_map__next(struct bpf_map *prev, struct bpf_object *obj)
1497 {
1498         size_t idx;
1499         struct bpf_map *s, *e;
1500
1501         if (!obj || !obj->maps)
1502                 return NULL;
1503
1504         s = obj->maps;
1505         e = obj->maps + obj->nr_maps;
1506
1507         if (prev == NULL)
1508                 return s;
1509
1510         if ((prev < s) || (prev >= e)) {
1511                 pr_warning("error in %s: map handler doesn't belong to object\n",
1512                            __func__);
1513                 return NULL;
1514         }
1515
1516         idx = (prev - obj->maps) + 1;
1517         if (idx >= obj->nr_maps)
1518                 return NULL;
1519         return &obj->maps[idx];
1520 }
1521
1522 struct bpf_map *
1523 bpf_object__find_map_by_name(struct bpf_object *obj, const char *name)
1524 {
1525         struct bpf_map *pos;
1526
1527         bpf_map__for_each(pos, obj) {
1528                 if (pos->name && !strcmp(pos->name, name))
1529                         return pos;
1530         }
1531         return NULL;
1532 }
1533
1534 struct bpf_map *
1535 bpf_object__find_map_by_offset(struct bpf_object *obj, size_t offset)
1536 {
1537         int i;
1538
1539         for (i = 0; i < obj->nr_maps; i++) {
1540                 if (obj->maps[i].offset == offset)
1541                         return &obj->maps[i];
1542         }
1543         return ERR_PTR(-ENOENT);
1544 }