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