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/err.h>
  32 #include <linux/kernel.h>
  33 #include <linux/bpf.h>
  34 #include <linux/list.h>
  35 #include <libelf.h>
  36 #include <gelf.h>
  37
  38 #include "libbpf.h"
  39 #include "bpf.h"
  40
  41 #ifndef EM_BPF
  42 #define EM_BPF 247
  43 #endif
  44
  45 #define __printf(a, b)  __attribute__((format(printf, a, b)))
  46
  47 __printf(1, 2)
  48 static int __base_pr(const char *format, ...)
  49 {
  50         va_list args;
  51         int err;
  52
  53         va_start(args, format);
  54         err = vfprintf(stderr, format, args);
  55         va_end(args);
  56         return err;
  57 }
  58
  59 static __printf(1, 2) libbpf_print_fn_t __pr_warning = __base_pr;
  60 static __printf(1, 2) libbpf_print_fn_t __pr_info = __base_pr;
  61 static __printf(1, 2) libbpf_print_fn_t __pr_debug;
  62
  63 #define __pr(func, fmt, ...)    \
  64 do {                            \
  65         if ((func))             \
  66                 (func)("libbpf: " fmt, ##__VA_ARGS__); \
  67 } while (0)
  68
  69 #define pr_warning(fmt, ...)    __pr(__pr_warning, fmt, ##__VA_ARGS__)
  70 #define pr_info(fmt, ...)       __pr(__pr_info, fmt, ##__VA_ARGS__)
  71 #define pr_debug(fmt, ...)      __pr(__pr_debug, fmt, ##__VA_ARGS__)
  72
  73 void libbpf_set_print(libbpf_print_fn_t warn,
  74                       libbpf_print_fn_t info,
  75                       libbpf_print_fn_t debug)
  76 {
  77         __pr_warning = warn;
  78         __pr_info = info;
  79         __pr_debug = debug;
  80 }
  81
  82 #define STRERR_BUFSIZE  128
  83
  84 #define ERRNO_OFFSET(e)         ((e) - __LIBBPF_ERRNO__START)
  85 #define ERRCODE_OFFSET(c)       ERRNO_OFFSET(LIBBPF_ERRNO__##c)
  86 #define NR_ERRNO        (__LIBBPF_ERRNO__END - __LIBBPF_ERRNO__START)
  87
  88 static const char *libbpf_strerror_table[NR_ERRNO] = {
  89         [ERRCODE_OFFSET(LIBELF)]        = "Something wrong in libelf",
  90         [ERRCODE_OFFSET(FORMAT)]        = "BPF object format invalid",
  91         [ERRCODE_OFFSET(KVERSION)]      = "'version' section incorrect or lost",
  92         [ERRCODE_OFFSET(ENDIAN)]        = "Endian mismatch",
  93         [ERRCODE_OFFSET(INTERNAL)]      = "Internal error in libbpf",
  94         [ERRCODE_OFFSET(RELOC)]         = "Relocation failed",
  95         [ERRCODE_OFFSET(VERIFY)]        = "Kernel verifier blocks program loading",
  96         [ERRCODE_OFFSET(PROG2BIG)]      = "Program too big",
  97         [ERRCODE_OFFSET(KVER)]          = "Incorrect kernel version",
  98         [ERRCODE_OFFSET(PROGTYPE)]      = "Kernel doesn't support this program type",
  99 };
 100
 101 int libbpf_strerror(int err, char *buf, size_t size)
 102 {
 103         if (!buf || !size)
 104                 return -1;
 105
 106         err = err > 0 ? err : -err;
 107
 108         if (err < __LIBBPF_ERRNO__START) {
 109                 int ret;
 110
 111                 ret = strerror_r(err, buf, size);
 112                 buf[size - 1] = '\0';
 113                 return ret;
 114         }
 115
 116         if (err < __LIBBPF_ERRNO__END) {
 117                 const char *msg;
 118
 119                 msg = libbpf_strerror_table[ERRNO_OFFSET(err)];
 120                 snprintf(buf, size, "%s", msg);
 121                 buf[size - 1] = '\0';
 122                 return 0;
 123         }
 124
 125         snprintf(buf, size, "Unknown libbpf error %d", err);
 126         buf[size - 1] = '\0';
 127         return -1;
 128 }
 129
 130 #define CHECK_ERR(action, err, out) do {        \
 131         err = action;                   \
 132         if (err)                        \
 133                 goto out;               \
 134 } while(0)
 135
 136
 137 /* Copied from tools/perf/util/util.h */
 138 #ifndef zfree
 139 # define zfree(ptr) ({ free(*ptr); *ptr = NULL; })
 140 #endif
 141
 142 #ifndef zclose
 143 # define zclose(fd) ({                  \
 144         int ___err = 0;                 \
 145         if ((fd) >= 0)                  \
 146                 ___err = close((fd));   \
 147         fd = -1;                        \
 148         ___err; })
 149 #endif
 150
 151 #ifdef HAVE_LIBELF_MMAP_SUPPORT
 152 # define LIBBPF_ELF_C_READ_MMAP ELF_C_READ_MMAP
 153 #else
 154 # define LIBBPF_ELF_C_READ_MMAP ELF_C_READ
 155 #endif
 156
 157 /*
 158  * bpf_prog should be a better name but it has been used in
 159  * linux/filter.h.
 160  */
 161 struct bpf_program {
 162         /* Index in elf obj file, for relocation use. */
 163         int idx;
 164         char *section_name;
 165         struct bpf_insn *insns;
 166         size_t insns_cnt;
 167         enum bpf_prog_type type;
 168
 169         struct {
 170                 int insn_idx;
 171                 int map_idx;
 172         } *reloc_desc;
 173         int nr_reloc;
 174
 175         struct {
 176                 int nr;
 177                 int *fds;
 178         } instances;
 179         bpf_program_prep_t preprocessor;
 180
 181         struct bpf_object *obj;
 182         void *priv;
 183         bpf_program_clear_priv_t clear_priv;
 184 };
 185
 186 struct bpf_map {
 187         int fd;
 188         char *name;
 189         size_t offset;
 190         struct bpf_map_def def;
 191         void *priv;
 192         bpf_map_clear_priv_t clear_priv;
 193 };
 194
 195 static LIST_HEAD(bpf_objects_list);
 196
 197 struct bpf_object {
 198         char license[64];
 199         u32 kern_version;
 200
 201         struct bpf_program *programs;
 202         size_t nr_programs;
 203         struct bpf_map *maps;
 204         size_t nr_maps;
 205
 206         bool loaded;
 207
 208         /*
 209          * Information when doing elf related work. Only valid if fd
 210          * is valid.
 211          */
 212         struct {
 213                 int fd;
 214                 void *obj_buf;
 215                 size_t obj_buf_sz;
 216                 Elf *elf;
 217                 GElf_Ehdr ehdr;
 218                 Elf_Data *symbols;
 219                 size_t strtabidx;
 220                 struct {
 221                         GElf_Shdr shdr;
 222                         Elf_Data *data;
 223                 } *reloc;
 224                 int nr_reloc;
 225                 int maps_shndx;
 226         } efile;
 227         /*
 228          * All loaded bpf_object is linked in a list, which is
 229          * hidden to caller. bpf_objects__<func> handlers deal with
 230          * all objects.
 231          */
 232         struct list_head list;
 233
 234         void *priv;
 235         bpf_object_clear_priv_t clear_priv;
 236
 237         char path[];
 238 };
 239 #define obj_elf_valid(o)        ((o)->efile.elf)
 240
 241 static void bpf_program__unload(struct bpf_program *prog)
 242 {
 243         int i;
 244
 245         if (!prog)
 246                 return;
 247
 248         /*
 249          * If the object is opened but the program was never loaded,
 250          * it is possible that prog->instances.nr == -1.
 251          */
 252         if (prog->instances.nr > 0) {
 253                 for (i = 0; i < prog->instances.nr; i++)
 254                         zclose(prog->instances.fds[i]);
 255         } else if (prog->instances.nr != -1) {
 256                 pr_warning("Internal error: instances.nr is %d\n",
 257                            prog->instances.nr);
 258         }
 259
 260         prog->instances.nr = -1;
 261         zfree(&prog->instances.fds);
 262 }
 263
 264 static void bpf_program__exit(struct bpf_program *prog)
 265 {
 266         if (!prog)
 267                 return;
 268
 269         if (prog->clear_priv)
 270                 prog->clear_priv(prog, prog->priv);
 271
 272         prog->priv = NULL;
 273         prog->clear_priv = NULL;
 274
 275         bpf_program__unload(prog);
 276         zfree(&prog->section_name);
 277         zfree(&prog->insns);
 278         zfree(&prog->reloc_desc);
 279
 280         prog->nr_reloc = 0;
 281         prog->insns_cnt = 0;
 282         prog->idx = -1;
 283 }
 284
 285 static int
 286 bpf_program__init(void *data, size_t size, char *name, int idx,
 287                     struct bpf_program *prog)
 288 {
 289         if (size < sizeof(struct bpf_insn)) {
 290                 pr_warning("corrupted section '%s'\n", name);
 291                 return -EINVAL;
 292         }
 293
 294         bzero(prog, sizeof(*prog));
 295
 296         prog->section_name = strdup(name);
 297         if (!prog->section_name) {
 298                 pr_warning("failed to alloc name for prog %s\n",
 299                            name);
 300                 goto errout;
 301         }
 302
 303         prog->insns = malloc(size);
 304         if (!prog->insns) {
 305                 pr_warning("failed to alloc insns for %s\n", name);
 306                 goto errout;
 307         }
 308         prog->insns_cnt = size / sizeof(struct bpf_insn);
 309         memcpy(prog->insns, data,
 310                prog->insns_cnt * sizeof(struct bpf_insn));
 311         prog->idx = idx;
 312         prog->instances.fds = NULL;
 313         prog->instances.nr = -1;
 314         prog->type = BPF_PROG_TYPE_KPROBE;
 315
 316         return 0;
 317 errout:
 318         bpf_program__exit(prog);
 319         return -ENOMEM;
 320 }
 321
 322 static int
 323 bpf_object__add_program(struct bpf_object *obj, void *data, size_t size,
 324                         char *name, int idx)
 325 {
 326         struct bpf_program prog, *progs;
 327         int nr_progs, err;
 328
 329         err = bpf_program__init(data, size, name, idx, &prog);
 330         if (err)
 331                 return err;
 332
 333         progs = obj->programs;
 334         nr_progs = obj->nr_programs;
 335
 336         progs = realloc(progs, sizeof(progs[0]) * (nr_progs + 1));
 337         if (!progs) {
 338                 /*
 339                  * In this case the original obj->programs
 340                  * is still valid, so don't need special treat for
 341                  * bpf_close_object().
 342                  */
 343                 pr_warning("failed to alloc a new program '%s'\n",
 344                            name);
 345                 bpf_program__exit(&prog);
 346                 return -ENOMEM;
 347         }
 348
 349         pr_debug("found program %s\n", prog.section_name);
 350         obj->programs = progs;
 351         obj->nr_programs = nr_progs + 1;
 352         prog.obj = obj;
 353         progs[nr_progs] = prog;
 354         return 0;
 355 }
 356
 357 static struct bpf_object *bpf_object__new(const char *path,
 358                                           void *obj_buf,
 359                                           size_t obj_buf_sz)
 360 {
 361         struct bpf_object *obj;
 362
 363         obj = calloc(1, sizeof(struct bpf_object) + strlen(path) + 1);
 364         if (!obj) {
 365                 pr_warning("alloc memory failed for %s\n", path);
 366                 return ERR_PTR(-ENOMEM);
 367         }
 368
 369         strcpy(obj->path, path);
 370         obj->efile.fd = -1;
 371
 372         /*
 373          * Caller of this function should also calls
 374          * bpf_object__elf_finish() after data collection to return
 375          * obj_buf to user. If not, we should duplicate the buffer to
 376          * avoid user freeing them before elf finish.
 377          */
 378         obj->efile.obj_buf = obj_buf;
 379         obj->efile.obj_buf_sz = obj_buf_sz;
 380         obj->efile.maps_shndx = -1;
 381
 382         obj->loaded = false;
 383
 384         INIT_LIST_HEAD(&obj->list);
 385         list_add(&obj->list, &bpf_objects_list);
 386         return obj;
 387 }
 388
 389 static void bpf_object__elf_finish(struct bpf_object *obj)
 390 {
 391         if (!obj_elf_valid(obj))
 392                 return;
 393
 394         if (obj->efile.elf) {
 395                 elf_end(obj->efile.elf);
 396                 obj->efile.elf = NULL;
 397         }
 398         obj->efile.symbols = NULL;
 399
 400         zfree(&obj->efile.reloc);
 401         obj->efile.nr_reloc = 0;
 402         zclose(obj->efile.fd);
 403         obj->efile.obj_buf = NULL;
 404         obj->efile.obj_buf_sz = 0;
 405 }
 406
 407 static int bpf_object__elf_init(struct bpf_object *obj)
 408 {
 409         int err = 0;
 410         GElf_Ehdr *ep;
 411
 412         if (obj_elf_valid(obj)) {
 413                 pr_warning("elf init: internal error\n");
 414                 return -LIBBPF_ERRNO__LIBELF;
 415         }
 416
 417         if (obj->efile.obj_buf_sz > 0) {
 418                 /*
 419                  * obj_buf should have been validated by
 420                  * bpf_object__open_buffer().
 421                  */
 422                 obj->efile.elf = elf_memory(obj->efile.obj_buf,
 423                                             obj->efile.obj_buf_sz);
 424         } else {
 425                 obj->efile.fd = open(obj->path, O_RDONLY);
 426                 if (obj->efile.fd < 0) {
 427                         pr_warning("failed to open %s: %s\n", obj->path,
 428                                         strerror(errno));
 429                         return -errno;
 430                 }
 431
 432                 obj->efile.elf = elf_begin(obj->efile.fd,
 433                                 LIBBPF_ELF_C_READ_MMAP,
 434                                 NULL);
 435         }
 436
 437         if (!obj->efile.elf) {
 438                 pr_warning("failed to open %s as ELF file\n",
 439                                 obj->path);
 440                 err = -LIBBPF_ERRNO__LIBELF;
 441                 goto errout;
 442         }
 443
 444         if (!gelf_getehdr(obj->efile.elf, &obj->efile.ehdr)) {
 445                 pr_warning("failed to get EHDR from %s\n",
 446                                 obj->path);
 447                 err = -LIBBPF_ERRNO__FORMAT;
 448                 goto errout;
 449         }
 450         ep = &obj->efile.ehdr;
 451
 452         /* Old LLVM set e_machine to EM_NONE */
 453         if ((ep->e_type != ET_REL) || (ep->e_machine && (ep->e_machine != EM_BPF))) {
 454                 pr_warning("%s is not an eBPF object file\n",
 455                         obj->path);
 456                 err = -LIBBPF_ERRNO__FORMAT;
 457                 goto errout;
 458         }
 459
 460         return 0;
 461 errout:
 462         bpf_object__elf_finish(obj);
 463         return err;
 464 }
 465
 466 static int
 467 bpf_object__check_endianness(struct bpf_object *obj)
 468 {
 469         static unsigned int const endian = 1;
 470
 471         switch (obj->efile.ehdr.e_ident[EI_DATA]) {
 472         case ELFDATA2LSB:
 473                 /* We are big endian, BPF obj is little endian. */
 474                 if (*(unsigned char const *)&endian != 1)
 475                         goto mismatch;
 476                 break;
 477
 478         case ELFDATA2MSB:
 479                 /* We are little endian, BPF obj is big endian. */
 480                 if (*(unsigned char const *)&endian != 0)
 481                         goto mismatch;
 482                 break;
 483         default:
 484                 return -LIBBPF_ERRNO__ENDIAN;
 485         }
 486
 487         return 0;
 488
 489 mismatch:
 490         pr_warning("Error: endianness mismatch.\n");
 491         return -LIBBPF_ERRNO__ENDIAN;
 492 }
 493
 494 static int
 495 bpf_object__init_license(struct bpf_object *obj,
 496                          void *data, size_t size)
 497 {
 498         memcpy(obj->license, data,
 499                min(size, sizeof(obj->license) - 1));
 500         pr_debug("license of %s is %s\n", obj->path, obj->license);
 501         return 0;
 502 }
 503
 504 static int
 505 bpf_object__init_kversion(struct bpf_object *obj,
 506                           void *data, size_t size)
 507 {
 508         u32 kver;
 509
 510         if (size != sizeof(kver)) {
 511                 pr_warning("invalid kver section in %s\n", obj->path);
 512                 return -LIBBPF_ERRNO__FORMAT;
 513         }
 514         memcpy(&kver, data, sizeof(kver));
 515         obj->kern_version = kver;
 516         pr_debug("kernel version of %s is %x\n", obj->path,
 517                  obj->kern_version);
 518         return 0;
 519 }
 520
 521 static int
 522 bpf_object__validate_maps(struct bpf_object *obj)
 523 {
 524         int i;
 525
 526         /*
 527          * If there's only 1 map, the only error case should have been
 528          * catched in bpf_object__init_maps().
 529          */
 530         if (!obj->maps || !obj->nr_maps || (obj->nr_maps == 1))
 531                 return 0;
 532
 533         for (i = 1; i < obj->nr_maps; i++) {
 534                 const struct bpf_map *a = &obj->maps[i - 1];
 535                 const struct bpf_map *b = &obj->maps[i];
 536
 537                 if (b->offset - a->offset < sizeof(struct bpf_map_def)) {
 538                         pr_warning("corrupted map section in %s: map \"%s\" too small\n",
 539                                    obj->path, a->name);
 540                         return -EINVAL;
 541                 }
 542         }
 543         return 0;
 544 }
 545
 546 static int compare_bpf_map(const void *_a, const void *_b)
 547 {
 548         const struct bpf_map *a = _a;
 549         const struct bpf_map *b = _b;
 550
 551         return a->offset - b->offset;
 552 }
 553
 554 static int
 555 bpf_object__init_maps(struct bpf_object *obj)
 556 {
 557         int i, map_idx, nr_maps = 0;
 558         Elf_Scn *scn;
 559         Elf_Data *data;
 560         Elf_Data *symbols = obj->efile.symbols;
 561
 562         if (obj->efile.maps_shndx < 0)
 563                 return -EINVAL;
 564         if (!symbols)
 565                 return -EINVAL;
 566
 567         scn = elf_getscn(obj->efile.elf, obj->efile.maps_shndx);
 568         if (scn)
 569                 data = elf_getdata(scn, NULL);
 570         if (!scn || !data) {
 571                 pr_warning("failed to get Elf_Data from map section %d\n",
 572                            obj->efile.maps_shndx);
 573                 return -EINVAL;
 574         }
 575
 576         /*
 577          * Count number of maps. Each map has a name.
 578          * Array of maps is not supported: only the first element is
 579          * considered.
 580          *
 581          * TODO: Detect array of map and report error.
 582          */
 583         for (i = 0; i < symbols->d_size / sizeof(GElf_Sym); i++) {
 584                 GElf_Sym sym;
 585
 586                 if (!gelf_getsym(symbols, i, &sym))
 587                         continue;
 588                 if (sym.st_shndx != obj->efile.maps_shndx)
 589                         continue;
 590                 nr_maps++;
 591         }
 592
 593         /* Alloc obj->maps and fill nr_maps. */
 594         pr_debug("maps in %s: %d maps in %zd bytes\n", obj->path,
 595                  nr_maps, data->d_size);
 596
 597         if (!nr_maps)
 598                 return 0;
 599
 600         obj->maps = calloc(nr_maps, sizeof(obj->maps[0]));
 601         if (!obj->maps) {
 602                 pr_warning("alloc maps for object failed\n");
 603                 return -ENOMEM;
 604         }
 605         obj->nr_maps = nr_maps;
 606
 607         /*
 608          * fill all fd with -1 so won't close incorrect
 609          * fd (fd=0 is stdin) when failure (zclose won't close
 610          * negative fd)).
 611          */
 612         for (i = 0; i < nr_maps; i++)
 613                 obj->maps[i].fd = -1;
 614
 615         /*
 616          * Fill obj->maps using data in "maps" section.
 617          */
 618         for (i = 0, map_idx = 0; i < symbols->d_size / sizeof(GElf_Sym); i++) {
 619                 GElf_Sym sym;
 620                 const char *map_name;
 621                 struct bpf_map_def *def;
 622
 623                 if (!gelf_getsym(symbols, i, &sym))
 624                         continue;
 625                 if (sym.st_shndx != obj->efile.maps_shndx)
 626                         continue;
 627
 628                 map_name = elf_strptr(obj->efile.elf,
 629                                       obj->efile.strtabidx,
 630                                       sym.st_name);
 631                 obj->maps[map_idx].offset = sym.st_value;
 632                 if (sym.st_value + sizeof(struct bpf_map_def) > data->d_size) {
 633                         pr_warning("corrupted maps section in %s: last map \"%s\" too small\n",
 634                                    obj->path, map_name);
 635                         return -EINVAL;
 636                 }
 637
 638                 obj->maps[map_idx].name = strdup(map_name);
 639                 if (!obj->maps[map_idx].name) {
 640                         pr_warning("failed to alloc map name\n");
 641                         return -ENOMEM;
 642                 }
 643                 pr_debug("map %d is \"%s\"\n", map_idx,
 644                          obj->maps[map_idx].name);
 645                 def = (struct bpf_map_def *)(data->d_buf + sym.st_value);
 646                 obj->maps[map_idx].def = *def;
 647                 map_idx++;
 648         }
 649
 650         qsort(obj->maps, obj->nr_maps, sizeof(obj->maps[0]), compare_bpf_map);
 651         return bpf_object__validate_maps(obj);
 652 }
 653
 654 static int bpf_object__elf_collect(struct bpf_object *obj)
 655 {
 656         Elf *elf = obj->efile.elf;
 657         GElf_Ehdr *ep = &obj->efile.ehdr;
 658         Elf_Scn *scn = NULL;
 659         int idx = 0, err = 0;
 660
 661         /* Elf is corrupted/truncated, avoid calling elf_strptr. */
 662         if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL)) {
 663                 pr_warning("failed to get e_shstrndx from %s\n",
 664                            obj->path);
 665                 return -LIBBPF_ERRNO__FORMAT;
 666         }
 667
 668         while ((scn = elf_nextscn(elf, scn)) != NULL) {
 669                 char *name;
 670                 GElf_Shdr sh;
 671                 Elf_Data *data;
 672
 673                 idx++;
 674                 if (gelf_getshdr(scn, &sh) != &sh) {
 675                         pr_warning("failed to get section header from %s\n",
 676                                    obj->path);
 677                         err = -LIBBPF_ERRNO__FORMAT;
 678                         goto out;
 679                 }
 680
 681                 name = elf_strptr(elf, ep->e_shstrndx, sh.sh_name);
 682                 if (!name) {
 683                         pr_warning("failed to get section name from %s\n",
 684                                    obj->path);
 685                         err = -LIBBPF_ERRNO__FORMAT;
 686                         goto out;
 687                 }
 688
 689                 data = elf_getdata(scn, 0);
 690                 if (!data) {
 691                         pr_warning("failed to get section data from %s(%s)\n",
 692                                    name, obj->path);
 693                         err = -LIBBPF_ERRNO__FORMAT;
 694                         goto out;
 695                 }
 696                 pr_debug("section %s, size %ld, link %d, flags %lx, type=%d\n",
 697                          name, (unsigned long)data->d_size,
 698                          (int)sh.sh_link, (unsigned long)sh.sh_flags,
 699                          (int)sh.sh_type);
 700
 701                 if (strcmp(name, "license") == 0)
 702                         err = bpf_object__init_license(obj,
 703                                                        data->d_buf,
 704                                                        data->d_size);
 705                 else if (strcmp(name, "version") == 0)
 706                         err = bpf_object__init_kversion(obj,
 707                                                         data->d_buf,
 708                                                         data->d_size);
 709                 else if (strcmp(name, "maps") == 0)
 710                         obj->efile.maps_shndx = idx;
 711                 else if (sh.sh_type == SHT_SYMTAB) {
 712                         if (obj->efile.symbols) {
 713                                 pr_warning("bpf: multiple SYMTAB in %s\n",
 714                                            obj->path);
 715                                 err = -LIBBPF_ERRNO__FORMAT;
 716                         } else {
 717                                 obj->efile.symbols = data;
 718                                 obj->efile.strtabidx = sh.sh_link;
 719                         }
 720                 } else if ((sh.sh_type == SHT_PROGBITS) &&
 721                            (sh.sh_flags & SHF_EXECINSTR) &&
 722                            (data->d_size > 0)) {
 723                         err = bpf_object__add_program(obj, data->d_buf,
 724                                                       data->d_size, name, idx);
 725                         if (err) {
 726                                 char errmsg[STRERR_BUFSIZE];
 727
 728                                 strerror_r(-err, errmsg, sizeof(errmsg));
 729                                 pr_warning("failed to alloc program %s (%s): %s",
 730                                            name, obj->path, errmsg);
 731                         }
 732                 } else if (sh.sh_type == SHT_REL) {
 733                         void *reloc = obj->efile.reloc;
 734                         int nr_reloc = obj->efile.nr_reloc + 1;
 735
 736                         reloc = realloc(reloc,
 737                                         sizeof(*obj->efile.reloc) * nr_reloc);
 738                         if (!reloc) {
 739                                 pr_warning("realloc failed\n");
 740                                 err = -ENOMEM;
 741                         } else {
 742                                 int n = nr_reloc - 1;
 743
 744                                 obj->efile.reloc = reloc;
 745                                 obj->efile.nr_reloc = nr_reloc;
 746
 747                                 obj->efile.reloc[n].shdr = sh;
 748                                 obj->efile.reloc[n].data = data;
 749                         }
 750                 }
 751                 if (err)
 752                         goto out;
 753         }
 754
 755         if (!obj->efile.strtabidx || obj->efile.strtabidx >= idx) {
 756                 pr_warning("Corrupted ELF file: index of strtab invalid\n");
 757                 return LIBBPF_ERRNO__FORMAT;
 758         }
 759         if (obj->efile.maps_shndx >= 0)
 760                 err = bpf_object__init_maps(obj);
 761 out:
 762         return err;
 763 }
 764
 765 static struct bpf_program *
 766 bpf_object__find_prog_by_idx(struct bpf_object *obj, int idx)
 767 {
 768         struct bpf_program *prog;
 769         size_t i;
 770
 771         for (i = 0; i < obj->nr_programs; i++) {
 772                 prog = &obj->programs[i];
 773                 if (prog->idx == idx)
 774                         return prog;
 775         }
 776         return NULL;
 777 }
 778
 779 static int
 780 bpf_program__collect_reloc(struct bpf_program *prog,
 781                            size_t nr_maps, GElf_Shdr *shdr,
 782                            Elf_Data *data, Elf_Data *symbols,
 783                            int maps_shndx, struct bpf_map *maps)
 784 {
 785         int i, nrels;
 786
 787         pr_debug("collecting relocating info for: '%s'\n",
 788                  prog->section_name);
 789         nrels = shdr->sh_size / shdr->sh_entsize;
 790
 791         prog->reloc_desc = malloc(sizeof(*prog->reloc_desc) * nrels);
 792         if (!prog->reloc_desc) {
 793                 pr_warning("failed to alloc memory in relocation\n");
 794                 return -ENOMEM;
 795         }
 796         prog->nr_reloc = nrels;
 797
 798         for (i = 0; i < nrels; i++) {
 799                 GElf_Sym sym;
 800                 GElf_Rel rel;
 801                 unsigned int insn_idx;
 802                 struct bpf_insn *insns = prog->insns;
 803                 size_t map_idx;
 804
 805                 if (!gelf_getrel(data, i, &rel)) {
 806                         pr_warning("relocation: failed to get %d reloc\n", i);
 807                         return -LIBBPF_ERRNO__FORMAT;
 808                 }
 809
 810                 if (!gelf_getsym(symbols,
 811                                  GELF_R_SYM(rel.r_info),
 812                                  &sym)) {
 813                         pr_warning("relocation: symbol %"PRIx64" not found\n",
 814                                    GELF_R_SYM(rel.r_info));
 815                         return -LIBBPF_ERRNO__FORMAT;
 816                 }
 817
 818                 if (sym.st_shndx != maps_shndx) {
 819                         pr_warning("Program '%s' contains non-map related relo data pointing to section %u\n",
 820                                    prog->section_name, sym.st_shndx);
 821                         return -LIBBPF_ERRNO__RELOC;
 822                 }
 823
 824                 insn_idx = rel.r_offset / sizeof(struct bpf_insn);
 825                 pr_debug("relocation: insn_idx=%u\n", insn_idx);
 826
 827                 if (insns[insn_idx].code != (BPF_LD | BPF_IMM | BPF_DW)) {
 828                         pr_warning("bpf: relocation: invalid relo for insns[%d].code 0x%x\n",
 829                                    insn_idx, insns[insn_idx].code);
 830                         return -LIBBPF_ERRNO__RELOC;
 831                 }
 832
 833                 /* TODO: 'maps' is sorted. We can use bsearch to make it faster. */
 834                 for (map_idx = 0; map_idx < nr_maps; map_idx++) {
 835                         if (maps[map_idx].offset == sym.st_value) {
 836                                 pr_debug("relocation: find map %zd (%s) for insn %u\n",
 837                                          map_idx, maps[map_idx].name, insn_idx);
 838                                 break;
 839                         }
 840                 }
 841
 842                 if (map_idx >= nr_maps) {
 843                         pr_warning("bpf relocation: map_idx %d large than %d\n",
 844                                    (int)map_idx, (int)nr_maps - 1);
 845                         return -LIBBPF_ERRNO__RELOC;
 846                 }
 847
 848                 prog->reloc_desc[i].insn_idx = insn_idx;
 849                 prog->reloc_desc[i].map_idx = map_idx;
 850         }
 851         return 0;
 852 }
 853
 854 static int
 855 bpf_object__create_maps(struct bpf_object *obj)
 856 {
 857         unsigned int i;
 858
 859         for (i = 0; i < obj->nr_maps; i++) {
 860                 struct bpf_map_def *def = &obj->maps[i].def;
 861                 int *pfd = &obj->maps[i].fd;
 862
 863                 *pfd = bpf_create_map(def->type,
 864                                       def->key_size,
 865                                       def->value_size,
 866                                       def->max_entries,
 867                                       0);
 868                 if (*pfd < 0) {
 869                         size_t j;
 870                         int err = *pfd;
 871
 872                         pr_warning("failed to create map: %s\n",
 873                                    strerror(errno));
 874                         for (j = 0; j < i; j++)
 875                                 zclose(obj->maps[j].fd);
 876                         return err;
 877                 }
 878                 pr_debug("create map %s: fd=%d\n", obj->maps[i].name, *pfd);
 879         }
 880
 881         return 0;
 882 }
 883
 884 static int
 885 bpf_program__relocate(struct bpf_program *prog, struct bpf_object *obj)
 886 {
 887         int i;
 888
 889         if (!prog || !prog->reloc_desc)
 890                 return 0;
 891
 892         for (i = 0; i < prog->nr_reloc; i++) {
 893                 int insn_idx, map_idx;
 894                 struct bpf_insn *insns = prog->insns;
 895
 896                 insn_idx = prog->reloc_desc[i].insn_idx;
 897                 map_idx = prog->reloc_desc[i].map_idx;
 898
 899                 if (insn_idx >= (int)prog->insns_cnt) {
 900                         pr_warning("relocation out of range: '%s'\n",
 901                                    prog->section_name);
 902                         return -LIBBPF_ERRNO__RELOC;
 903                 }
 904                 insns[insn_idx].src_reg = BPF_PSEUDO_MAP_FD;
 905                 insns[insn_idx].imm = obj->maps[map_idx].fd;
 906         }
 907
 908         zfree(&prog->reloc_desc);
 909         prog->nr_reloc = 0;
 910         return 0;
 911 }
 912
 913
 914 static int
 915 bpf_object__relocate(struct bpf_object *obj)
 916 {
 917         struct bpf_program *prog;
 918         size_t i;
 919         int err;
 920
 921         for (i = 0; i < obj->nr_programs; i++) {
 922                 prog = &obj->programs[i];
 923
 924                 err = bpf_program__relocate(prog, obj);
 925                 if (err) {
 926                         pr_warning("failed to relocate '%s'\n",
 927                                    prog->section_name);
 928                         return err;
 929                 }
 930         }
 931         return 0;
 932 }
 933
 934 static int bpf_object__collect_reloc(struct bpf_object *obj)
 935 {
 936         int i, err;
 937
 938         if (!obj_elf_valid(obj)) {
 939                 pr_warning("Internal error: elf object is closed\n");
 940                 return -LIBBPF_ERRNO__INTERNAL;
 941         }
 942
 943         for (i = 0; i < obj->efile.nr_reloc; i++) {
 944                 GElf_Shdr *shdr = &obj->efile.reloc[i].shdr;
 945                 Elf_Data *data = obj->efile.reloc[i].data;
 946                 int idx = shdr->sh_info;
 947                 struct bpf_program *prog;
 948                 size_t nr_maps = obj->nr_maps;
 949
 950                 if (shdr->sh_type != SHT_REL) {
 951                         pr_warning("internal error at %d\n", __LINE__);
 952                         return -LIBBPF_ERRNO__INTERNAL;
 953                 }
 954
 955                 prog = bpf_object__find_prog_by_idx(obj, idx);
 956                 if (!prog) {
 957                         pr_warning("relocation failed: no %d section\n",
 958                                    idx);
 959                         return -LIBBPF_ERRNO__RELOC;
 960                 }
 961
 962                 err = bpf_program__collect_reloc(prog, nr_maps,
 963                                                  shdr, data,
 964                                                  obj->efile.symbols,
 965                                                  obj->efile.maps_shndx,
 966                                                  obj->maps);
 967                 if (err)
 968                         return err;
 969         }
 970         return 0;
 971 }
 972
 973 static int
 974 load_program(enum bpf_prog_type type, struct bpf_insn *insns,
 975              int insns_cnt, char *license, u32 kern_version, int *pfd)
 976 {
 977         int ret;
 978         char *log_buf;
 979
 980         if (!insns || !insns_cnt)
 981                 return -EINVAL;
 982
 983         log_buf = malloc(BPF_LOG_BUF_SIZE);
 984         if (!log_buf)
 985                 pr_warning("Alloc log buffer for bpf loader error, continue without log\n");
 986
 987         ret = bpf_load_program(type, insns, insns_cnt, license,
 988                                kern_version, log_buf, BPF_LOG_BUF_SIZE);
 989
 990         if (ret >= 0) {
 991                 *pfd = ret;
 992                 ret = 0;
 993                 goto out;
 994         }
 995
 996         ret = -LIBBPF_ERRNO__LOAD;
 997         pr_warning("load bpf program failed: %s\n", strerror(errno));
 998
 999         if (log_buf && log_buf[0] != '\0') {
1000                 ret = -LIBBPF_ERRNO__VERIFY;
1001                 pr_warning("-- BEGIN DUMP LOG ---\n");
1002                 pr_warning("\n%s\n", log_buf);
1003                 pr_warning("-- END LOG --\n");
1004         } else if (insns_cnt >= BPF_MAXINSNS) {
1005                 pr_warning("Program too large (%d insns), at most %d insns\n",
1006                            insns_cnt, BPF_MAXINSNS);
1007                 ret = -LIBBPF_ERRNO__PROG2BIG;
1008         } else {
1009                 /* Wrong program type? */
1010                 if (type != BPF_PROG_TYPE_KPROBE) {
1011                         int fd;
1012
1013                         fd = bpf_load_program(BPF_PROG_TYPE_KPROBE, insns,
1014                                               insns_cnt, license, kern_version,
1015                                               NULL, 0);
1016                         if (fd >= 0) {
1017                                 close(fd);
1018                                 ret = -LIBBPF_ERRNO__PROGTYPE;
1019                                 goto out;
1020                         }
1021                 }
1022
1023                 if (log_buf)
1024                         ret = -LIBBPF_ERRNO__KVER;
1025         }
1026
1027 out:
1028         free(log_buf);
1029         return ret;
1030 }
1031
1032 static int
1033 bpf_program__load(struct bpf_program *prog,
1034                   char *license, u32 kern_version)
1035 {
1036         int err = 0, fd, i;
1037
1038         if (prog->instances.nr < 0 || !prog->instances.fds) {
1039                 if (prog->preprocessor) {
1040                         pr_warning("Internal error: can't load program '%s'\n",
1041                                    prog->section_name);
1042                         return -LIBBPF_ERRNO__INTERNAL;
1043                 }
1044
1045                 prog->instances.fds = malloc(sizeof(int));
1046                 if (!prog->instances.fds) {
1047                         pr_warning("Not enough memory for BPF fds\n");
1048                         return -ENOMEM;
1049                 }
1050                 prog->instances.nr = 1;
1051                 prog->instances.fds[0] = -1;
1052         }
1053
1054         if (!prog->preprocessor) {
1055                 if (prog->instances.nr != 1) {
1056                         pr_warning("Program '%s' is inconsistent: nr(%d) != 1\n",
1057                                    prog->section_name, prog->instances.nr);
1058                 }
1059                 err = load_program(prog->type, prog->insns, prog->insns_cnt,
1060                                    license, kern_version, &fd);
1061                 if (!err)
1062                         prog->instances.fds[0] = fd;
1063                 goto out;
1064         }
1065
1066         for (i = 0; i < prog->instances.nr; i++) {
1067                 struct bpf_prog_prep_result result;
1068                 bpf_program_prep_t preprocessor = prog->preprocessor;
1069
1070                 bzero(&result, sizeof(result));
1071                 err = preprocessor(prog, i, prog->insns,
1072                                    prog->insns_cnt, &result);
1073                 if (err) {
1074                         pr_warning("Preprocessing the %dth instance of program '%s' failed\n",
1075                                    i, prog->section_name);
1076                         goto out;
1077                 }
1078
1079                 if (!result.new_insn_ptr || !result.new_insn_cnt) {
1080                         pr_debug("Skip loading the %dth instance of program '%s'\n",
1081                                  i, prog->section_name);
1082                         prog->instances.fds[i] = -1;
1083                         if (result.pfd)
1084                                 *result.pfd = -1;
1085                         continue;
1086                 }
1087
1088                 err = load_program(prog->type, result.new_insn_ptr,
1089                                    result.new_insn_cnt,
1090                                    license, kern_version, &fd);
1091
1092                 if (err) {
1093                         pr_warning("Loading the %dth instance of program '%s' failed\n",
1094                                         i, prog->section_name);
1095                         goto out;
1096                 }
1097
1098                 if (result.pfd)
1099                         *result.pfd = fd;
1100                 prog->instances.fds[i] = fd;
1101         }
1102 out:
1103         if (err)
1104                 pr_warning("failed to load program '%s'\n",
1105                            prog->section_name);
1106         zfree(&prog->insns);
1107         prog->insns_cnt = 0;
1108         return err;
1109 }
1110
1111 static int
1112 bpf_object__load_progs(struct bpf_object *obj)
1113 {
1114         size_t i;
1115         int err;
1116
1117         for (i = 0; i < obj->nr_programs; i++) {
1118                 err = bpf_program__load(&obj->programs[i],
1119                                         obj->license,
1120                                         obj->kern_version);
1121                 if (err)
1122                         return err;
1123         }
1124         return 0;
1125 }
1126
1127 static int bpf_object__validate(struct bpf_object *obj)
1128 {
1129         if (obj->kern_version == 0) {
1130                 pr_warning("%s doesn't provide kernel version\n",
1131                            obj->path);
1132                 return -LIBBPF_ERRNO__KVERSION;
1133         }
1134         return 0;
1135 }
1136
1137 static struct bpf_object *
1138 __bpf_object__open(const char *path, void *obj_buf, size_t obj_buf_sz)
1139 {
1140         struct bpf_object *obj;
1141         int err;
1142
1143         if (elf_version(EV_CURRENT) == EV_NONE) {
1144                 pr_warning("failed to init libelf for %s\n", path);
1145                 return ERR_PTR(-LIBBPF_ERRNO__LIBELF);
1146         }
1147
1148         obj = bpf_object__new(path, obj_buf, obj_buf_sz);
1149         if (IS_ERR(obj))
1150                 return obj;
1151
1152         CHECK_ERR(bpf_object__elf_init(obj), err, out);
1153         CHECK_ERR(bpf_object__check_endianness(obj), err, out);
1154         CHECK_ERR(bpf_object__elf_collect(obj), err, out);
1155         CHECK_ERR(bpf_object__collect_reloc(obj), err, out);
1156         CHECK_ERR(bpf_object__validate(obj), err, out);
1157
1158         bpf_object__elf_finish(obj);
1159         return obj;
1160 out:
1161         bpf_object__close(obj);
1162         return ERR_PTR(err);
1163 }
1164
1165 struct bpf_object *bpf_object__open(const char *path)
1166 {
1167         /* param validation */
1168         if (!path)
1169                 return NULL;
1170
1171         pr_debug("loading %s\n", path);
1172
1173         return __bpf_object__open(path, NULL, 0);
1174 }
1175
1176 struct bpf_object *bpf_object__open_buffer(void *obj_buf,
1177                                            size_t obj_buf_sz,
1178                                            const char *name)
1179 {
1180         char tmp_name[64];
1181
1182         /* param validation */
1183         if (!obj_buf || obj_buf_sz <= 0)
1184                 return NULL;
1185
1186         if (!name) {
1187                 snprintf(tmp_name, sizeof(tmp_name), "%lx-%lx",
1188                          (unsigned long)obj_buf,
1189                          (unsigned long)obj_buf_sz);
1190                 tmp_name[sizeof(tmp_name) - 1] = '\0';
1191                 name = tmp_name;
1192         }
1193         pr_debug("loading object '%s' from buffer\n",
1194                  name);
1195
1196         return __bpf_object__open(name, obj_buf, obj_buf_sz);
1197 }
1198
1199 int bpf_object__unload(struct bpf_object *obj)
1200 {
1201         size_t i;
1202
1203         if (!obj)
1204                 return -EINVAL;
1205
1206         for (i = 0; i < obj->nr_maps; i++)
1207                 zclose(obj->maps[i].fd);
1208
1209         for (i = 0; i < obj->nr_programs; i++)
1210                 bpf_program__unload(&obj->programs[i]);
1211
1212         return 0;
1213 }
1214
1215 int bpf_object__load(struct bpf_object *obj)
1216 {
1217         int err;
1218
1219         if (!obj)
1220                 return -EINVAL;
1221
1222         if (obj->loaded) {
1223                 pr_warning("object should not be loaded twice\n");
1224                 return -EINVAL;
1225         }
1226
1227         obj->loaded = true;
1228
1229         CHECK_ERR(bpf_object__create_maps(obj), err, out);
1230         CHECK_ERR(bpf_object__relocate(obj), err, out);
1231         CHECK_ERR(bpf_object__load_progs(obj), err, out);
1232
1233         return 0;
1234 out:
1235         bpf_object__unload(obj);
1236         pr_warning("failed to load object '%s'\n", obj->path);
1237         return err;
1238 }
1239
1240 void bpf_object__close(struct bpf_object *obj)
1241 {
1242         size_t i;
1243
1244         if (!obj)
1245                 return;
1246
1247         if (obj->clear_priv)
1248                 obj->clear_priv(obj, obj->priv);
1249
1250         bpf_object__elf_finish(obj);
1251         bpf_object__unload(obj);
1252
1253         for (i = 0; i < obj->nr_maps; i++) {
1254                 zfree(&obj->maps[i].name);
1255                 if (obj->maps[i].clear_priv)
1256                         obj->maps[i].clear_priv(&obj->maps[i],
1257                                                 obj->maps[i].priv);
1258                 obj->maps[i].priv = NULL;
1259                 obj->maps[i].clear_priv = NULL;
1260         }
1261         zfree(&obj->maps);
1262         obj->nr_maps = 0;
1263
1264         if (obj->programs && obj->nr_programs) {
1265                 for (i = 0; i < obj->nr_programs; i++)
1266                         bpf_program__exit(&obj->programs[i]);
1267         }
1268         zfree(&obj->programs);
1269
1270         list_del(&obj->list);
1271         free(obj);
1272 }
1273
1274 struct bpf_object *
1275 bpf_object__next(struct bpf_object *prev)
1276 {
1277         struct bpf_object *next;
1278
1279         if (!prev)
1280                 next = list_first_entry(&bpf_objects_list,
1281                                         struct bpf_object,
1282                                         list);
1283         else
1284                 next = list_next_entry(prev, list);
1285
1286         /* Empty list is noticed here so don't need checking on entry. */
1287         if (&next->list == &bpf_objects_list)
1288                 return NULL;
1289
1290         return next;
1291 }
1292
1293 const char *bpf_object__name(struct bpf_object *obj)
1294 {
1295         return obj ? obj->path : ERR_PTR(-EINVAL);
1296 }
1297
1298 unsigned int bpf_object__kversion(struct bpf_object *obj)
1299 {
1300         return obj ? obj->kern_version : 0;
1301 }
1302
1303 int bpf_object__set_priv(struct bpf_object *obj, void *priv,
1304                          bpf_object_clear_priv_t clear_priv)
1305 {
1306         if (obj->priv && obj->clear_priv)
1307                 obj->clear_priv(obj, obj->priv);
1308
1309         obj->priv = priv;
1310         obj->clear_priv = clear_priv;
1311         return 0;
1312 }
1313
1314 void *bpf_object__priv(struct bpf_object *obj)
1315 {
1316         return obj ? obj->priv : ERR_PTR(-EINVAL);
1317 }
1318
1319 struct bpf_program *
1320 bpf_program__next(struct bpf_program *prev, struct bpf_object *obj)
1321 {
1322         size_t idx;
1323
1324         if (!obj->programs)
1325                 return NULL;
1326         /* First handler */
1327         if (prev == NULL)
1328                 return &obj->programs[0];
1329
1330         if (prev->obj != obj) {
1331                 pr_warning("error: program handler doesn't match object\n");
1332                 return NULL;
1333         }
1334
1335         idx = (prev - obj->programs) + 1;
1336         if (idx >= obj->nr_programs)
1337                 return NULL;
1338         return &obj->programs[idx];
1339 }
1340
1341 int bpf_program__set_priv(struct bpf_program *prog, void *priv,
1342                           bpf_program_clear_priv_t clear_priv)
1343 {
1344         if (prog->priv && prog->clear_priv)
1345                 prog->clear_priv(prog, prog->priv);
1346
1347         prog->priv = priv;
1348         prog->clear_priv = clear_priv;
1349         return 0;
1350 }
1351
1352 void *bpf_program__priv(struct bpf_program *prog)
1353 {
1354         return prog ? prog->priv : ERR_PTR(-EINVAL);
1355 }
1356
1357 const char *bpf_program__title(struct bpf_program *prog, bool needs_copy)
1358 {
1359         const char *title;
1360
1361         title = prog->section_name;
1362         if (needs_copy) {
1363                 title = strdup(title);
1364                 if (!title) {
1365                         pr_warning("failed to strdup program title\n");
1366                         return ERR_PTR(-ENOMEM);
1367                 }
1368         }
1369
1370         return title;
1371 }
1372
1373 int bpf_program__fd(struct bpf_program *prog)
1374 {
1375         return bpf_program__nth_fd(prog, 0);
1376 }
1377
1378 int bpf_program__set_prep(struct bpf_program *prog, int nr_instances,
1379                           bpf_program_prep_t prep)
1380 {
1381         int *instances_fds;
1382
1383         if (nr_instances <= 0 || !prep)
1384                 return -EINVAL;
1385
1386         if (prog->instances.nr > 0 || prog->instances.fds) {
1387                 pr_warning("Can't set pre-processor after loading\n");
1388                 return -EINVAL;
1389         }
1390
1391         instances_fds = malloc(sizeof(int) * nr_instances);
1392         if (!instances_fds) {
1393                 pr_warning("alloc memory failed for fds\n");
1394                 return -ENOMEM;
1395         }
1396
1397         /* fill all fd with -1 */
1398         memset(instances_fds, -1, sizeof(int) * nr_instances);
1399
1400         prog->instances.nr = nr_instances;
1401         prog->instances.fds = instances_fds;
1402         prog->preprocessor = prep;
1403         return 0;
1404 }
1405
1406 int bpf_program__nth_fd(struct bpf_program *prog, int n)
1407 {
1408         int fd;
1409
1410         if (n >= prog->instances.nr || n < 0) {
1411                 pr_warning("Can't get the %dth fd from program %s: only %d instances\n",
1412                            n, prog->section_name, prog->instances.nr);
1413                 return -EINVAL;
1414         }
1415
1416         fd = prog->instances.fds[n];
1417         if (fd < 0) {
1418                 pr_warning("%dth instance of program '%s' is invalid\n",
1419                            n, prog->section_name);
1420                 return -ENOENT;
1421         }
1422
1423         return fd;
1424 }
1425
1426 static void bpf_program__set_type(struct bpf_program *prog,
1427                                   enum bpf_prog_type type)
1428 {
1429         prog->type = type;
1430 }
1431
1432 static bool bpf_program__is_type(struct bpf_program *prog,
1433                                  enum bpf_prog_type type)
1434 {
1435         return prog ? (prog->type == type) : false;
1436 }
1437
1438 #define BPF_PROG_TYPE_FNS(NAME, TYPE)                   \
1439 int bpf_program__set_##NAME(struct bpf_program *prog)   \
1440 {                                                       \
1441         if (!prog)                                      \
1442                 return -EINVAL;                         \
1443         bpf_program__set_type(prog, TYPE);              \
1444         return 0;                                       \
1445 }                                                       \
1446                                                         \
1447 bool bpf_program__is_##NAME(struct bpf_program *prog)   \
1448 {                                                       \
1449         return bpf_program__is_type(prog, TYPE);        \
1450 }                                                       \
1451
1452 BPF_PROG_TYPE_FNS(socket_filter, BPF_PROG_TYPE_SOCKET_FILTER);
1453 BPF_PROG_TYPE_FNS(kprobe, BPF_PROG_TYPE_KPROBE);
1454 BPF_PROG_TYPE_FNS(sched_cls, BPF_PROG_TYPE_SCHED_CLS);
1455 BPF_PROG_TYPE_FNS(sched_act, BPF_PROG_TYPE_SCHED_ACT);
1456 BPF_PROG_TYPE_FNS(tracepoint, BPF_PROG_TYPE_TRACEPOINT);
1457 BPF_PROG_TYPE_FNS(xdp, BPF_PROG_TYPE_XDP);
1458 BPF_PROG_TYPE_FNS(perf_event, BPF_PROG_TYPE_PERF_EVENT);
1459
1460 int bpf_map__fd(struct bpf_map *map)
1461 {
1462         return map ? map->fd : -EINVAL;
1463 }
1464
1465 const struct bpf_map_def *bpf_map__def(struct bpf_map *map)
1466 {
1467         return map ? &map->def : ERR_PTR(-EINVAL);
1468 }
1469
1470 const char *bpf_map__name(struct bpf_map *map)
1471 {
1472         return map ? map->name : NULL;
1473 }
1474
1475 int bpf_map__set_priv(struct bpf_map *map, void *priv,
1476                      bpf_map_clear_priv_t clear_priv)
1477 {
1478         if (!map)
1479                 return -EINVAL;
1480
1481         if (map->priv) {
1482                 if (map->clear_priv)
1483                         map->clear_priv(map, map->priv);
1484         }
1485
1486         map->priv = priv;
1487         map->clear_priv = clear_priv;
1488         return 0;
1489 }
1490
1491 void *bpf_map__priv(struct bpf_map *map)
1492 {
1493         return map ? map->priv : ERR_PTR(-EINVAL);
1494 }
1495
1496 struct bpf_map *
1497 bpf_map__next(struct bpf_map *prev, struct bpf_object *obj)
1498 {
1499         size_t idx;
1500         struct bpf_map *s, *e;
1501
1502         if (!obj || !obj->maps)
1503                 return NULL;
1504
1505         s = obj->maps;
1506         e = obj->maps + obj->nr_maps;
1507
1508         if (prev == NULL)
1509                 return s;
1510
1511         if ((prev < s) || (prev >= e)) {
1512                 pr_warning("error in %s: map handler doesn't belong to object\n",
1513                            __func__);
1514                 return NULL;
1515         }
1516
1517         idx = (prev - obj->maps) + 1;
1518         if (idx >= obj->nr_maps)
1519                 return NULL;
1520         return &obj->maps[idx];
1521 }
1522
1523 struct bpf_map *
1524 bpf_object__find_map_by_name(struct bpf_object *obj, const char *name)
1525 {
1526         struct bpf_map *pos;
1527
1528         bpf_map__for_each(pos, obj) {
1529                 if (pos->name && !strcmp(pos->name, name))
1530                         return pos;
1531         }
1532         return NULL;
1533 }
1534
1535 struct bpf_map *
1536 bpf_object__find_map_by_offset(struct bpf_object *obj, size_t offset)
1537 {
1538         int i;
1539
1540         for (i = 0; i < obj->nr_maps; i++) {
1541                 if (obj->maps[i].offset == offset)
1542                         return &obj->maps[i];
1543         }
1544         return ERR_PTR(-ENOENT);
1545 }
1546
1547 long libbpf_get_error(const void *ptr)
1548 {
1549         if (IS_ERR(ptr))
1550                 return PTR_ERR(ptr);
1551         return 0;
1552 }