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
   9 #include <stdlib.h>
  10 #include <stdio.h>
  11 #include <stdarg.h>
  12 #include <inttypes.h>
  13 #include <string.h>
  14 #include <unistd.h>
  15 #include <fcntl.h>
  16 #include <errno.h>
  17 #include <asm/unistd.h>
  18 #include <linux/kernel.h>
  19 #include <linux/bpf.h>
  20 #include <linux/list.h>
  21 #include <libelf.h>
  22 #include <gelf.h>
  23
  24 #include "libbpf.h"
  25 #include "bpf.h"
  26
  27 #define __printf(a, b)  __attribute__((format(printf, a, b)))
  28
  29 __printf(1, 2)
  30 static int __base_pr(const char *format, ...)
  31 {
  32         va_list args;
  33         int err;
  34
  35         va_start(args, format);
  36         err = vfprintf(stderr, format, args);
  37         va_end(args);
  38         return err;
  39 }
  40
  41 static __printf(1, 2) libbpf_print_fn_t __pr_warning = __base_pr;
  42 static __printf(1, 2) libbpf_print_fn_t __pr_info = __base_pr;
  43 static __printf(1, 2) libbpf_print_fn_t __pr_debug;
  44
  45 #define __pr(func, fmt, ...)    \
  46 do {                            \
  47         if ((func))             \
  48                 (func)("libbpf: " fmt, ##__VA_ARGS__); \
  49 } while (0)
  50
  51 #define pr_warning(fmt, ...)    __pr(__pr_warning, fmt, ##__VA_ARGS__)
  52 #define pr_info(fmt, ...)       __pr(__pr_info, fmt, ##__VA_ARGS__)
  53 #define pr_debug(fmt, ...)      __pr(__pr_debug, fmt, ##__VA_ARGS__)
  54
  55 void libbpf_set_print(libbpf_print_fn_t warn,
  56                       libbpf_print_fn_t info,
  57                       libbpf_print_fn_t debug)
  58 {
  59         __pr_warning = warn;
  60         __pr_info = info;
  61         __pr_debug = debug;
  62 }
  63
  64 /* Copied from tools/perf/util/util.h */
  65 #ifndef zfree
  66 # define zfree(ptr) ({ free(*ptr); *ptr = NULL; })
  67 #endif
  68
  69 #ifndef zclose
  70 # define zclose(fd) ({                  \
  71         int ___err = 0;                 \
  72         if ((fd) >= 0)                  \
  73                 ___err = close((fd));   \
  74         fd = -1;                        \
  75         ___err; })
  76 #endif
  77
  78 #ifdef HAVE_LIBELF_MMAP_SUPPORT
  79 # define LIBBPF_ELF_C_READ_MMAP ELF_C_READ_MMAP
  80 #else
  81 # define LIBBPF_ELF_C_READ_MMAP ELF_C_READ
  82 #endif
  83
  84 /*
  85  * bpf_prog should be a better name but it has been used in
  86  * linux/filter.h.
  87  */
  88 struct bpf_program {
  89         /* Index in elf obj file, for relocation use. */
  90         int idx;
  91         char *section_name;
  92         struct bpf_insn *insns;
  93         size_t insns_cnt;
  94
  95         struct {
  96                 int insn_idx;
  97                 int map_idx;
  98         } *reloc_desc;
  99         int nr_reloc;
 100
 101         int fd;
 102
 103         struct bpf_object *obj;
 104         void *priv;
 105         bpf_program_clear_priv_t clear_priv;
 106 };
 107
 108 static LIST_HEAD(bpf_objects_list);
 109
 110 struct bpf_object {
 111         char license[64];
 112         u32 kern_version;
 113         void *maps_buf;
 114         size_t maps_buf_sz;
 115
 116         struct bpf_program *programs;
 117         size_t nr_programs;
 118         int *map_fds;
 119         /*
 120          * This field is required because maps_buf will be freed and
 121          * maps_buf_sz will be set to 0 after loaded.
 122          */
 123         size_t nr_map_fds;
 124         bool loaded;
 125
 126         /*
 127          * Information when doing elf related work. Only valid if fd
 128          * is valid.
 129          */
 130         struct {
 131                 int fd;
 132                 void *obj_buf;
 133                 size_t obj_buf_sz;
 134                 Elf *elf;
 135                 GElf_Ehdr ehdr;
 136                 Elf_Data *symbols;
 137                 struct {
 138                         GElf_Shdr shdr;
 139                         Elf_Data *data;
 140                 } *reloc;
 141                 int nr_reloc;
 142         } efile;
 143         /*
 144          * All loaded bpf_object is linked in a list, which is
 145          * hidden to caller. bpf_objects__<func> handlers deal with
 146          * all objects.
 147          */
 148         struct list_head list;
 149         char path[];
 150 };
 151 #define obj_elf_valid(o)        ((o)->efile.elf)
 152
 153 static void bpf_program__unload(struct bpf_program *prog)
 154 {
 155         if (!prog)
 156                 return;
 157
 158         zclose(prog->fd);
 159 }
 160
 161 static void bpf_program__exit(struct bpf_program *prog)
 162 {
 163         if (!prog)
 164                 return;
 165
 166         if (prog->clear_priv)
 167                 prog->clear_priv(prog, prog->priv);
 168
 169         prog->priv = NULL;
 170         prog->clear_priv = NULL;
 171
 172         bpf_program__unload(prog);
 173         zfree(&prog->section_name);
 174         zfree(&prog->insns);
 175         zfree(&prog->reloc_desc);
 176
 177         prog->nr_reloc = 0;
 178         prog->insns_cnt = 0;
 179         prog->idx = -1;
 180 }
 181
 182 static int
 183 bpf_program__init(void *data, size_t size, char *name, int idx,
 184                     struct bpf_program *prog)
 185 {
 186         if (size < sizeof(struct bpf_insn)) {
 187                 pr_warning("corrupted section '%s'\n", name);
 188                 return -EINVAL;
 189         }
 190
 191         bzero(prog, sizeof(*prog));
 192
 193         prog->section_name = strdup(name);
 194         if (!prog->section_name) {
 195                 pr_warning("failed to alloc name for prog %s\n",
 196                            name);
 197                 goto errout;
 198         }
 199
 200         prog->insns = malloc(size);
 201         if (!prog->insns) {
 202                 pr_warning("failed to alloc insns for %s\n", name);
 203                 goto errout;
 204         }
 205         prog->insns_cnt = size / sizeof(struct bpf_insn);
 206         memcpy(prog->insns, data,
 207                prog->insns_cnt * sizeof(struct bpf_insn));
 208         prog->idx = idx;
 209         prog->fd = -1;
 210
 211         return 0;
 212 errout:
 213         bpf_program__exit(prog);
 214         return -ENOMEM;
 215 }
 216
 217 static int
 218 bpf_object__add_program(struct bpf_object *obj, void *data, size_t size,
 219                         char *name, int idx)
 220 {
 221         struct bpf_program prog, *progs;
 222         int nr_progs, err;
 223
 224         err = bpf_program__init(data, size, name, idx, &prog);
 225         if (err)
 226                 return err;
 227
 228         progs = obj->programs;
 229         nr_progs = obj->nr_programs;
 230
 231         progs = realloc(progs, sizeof(progs[0]) * (nr_progs + 1));
 232         if (!progs) {
 233                 /*
 234                  * In this case the original obj->programs
 235                  * is still valid, so don't need special treat for
 236                  * bpf_close_object().
 237                  */
 238                 pr_warning("failed to alloc a new program '%s'\n",
 239                            name);
 240                 bpf_program__exit(&prog);
 241                 return -ENOMEM;
 242         }
 243
 244         pr_debug("found program %s\n", prog.section_name);
 245         obj->programs = progs;
 246         obj->nr_programs = nr_progs + 1;
 247         prog.obj = obj;
 248         progs[nr_progs] = prog;
 249         return 0;
 250 }
 251
 252 static struct bpf_object *bpf_object__new(const char *path,
 253                                           void *obj_buf,
 254                                           size_t obj_buf_sz)
 255 {
 256         struct bpf_object *obj;
 257
 258         obj = calloc(1, sizeof(struct bpf_object) + strlen(path) + 1);
 259         if (!obj) {
 260                 pr_warning("alloc memory failed for %s\n", path);
 261                 return NULL;
 262         }
 263
 264         strcpy(obj->path, path);
 265         obj->efile.fd = -1;
 266
 267         /*
 268          * Caller of this function should also calls
 269          * bpf_object__elf_finish() after data collection to return
 270          * obj_buf to user. If not, we should duplicate the buffer to
 271          * avoid user freeing them before elf finish.
 272          */
 273         obj->efile.obj_buf = obj_buf;
 274         obj->efile.obj_buf_sz = obj_buf_sz;
 275
 276         obj->loaded = false;
 277
 278         INIT_LIST_HEAD(&obj->list);
 279         list_add(&obj->list, &bpf_objects_list);
 280         return obj;
 281 }
 282
 283 static void bpf_object__elf_finish(struct bpf_object *obj)
 284 {
 285         if (!obj_elf_valid(obj))
 286                 return;
 287
 288         if (obj->efile.elf) {
 289                 elf_end(obj->efile.elf);
 290                 obj->efile.elf = NULL;
 291         }
 292         obj->efile.symbols = NULL;
 293
 294         zfree(&obj->efile.reloc);
 295         obj->efile.nr_reloc = 0;
 296         zclose(obj->efile.fd);
 297         obj->efile.obj_buf = NULL;
 298         obj->efile.obj_buf_sz = 0;
 299 }
 300
 301 static int bpf_object__elf_init(struct bpf_object *obj)
 302 {
 303         int err = 0;
 304         GElf_Ehdr *ep;
 305
 306         if (obj_elf_valid(obj)) {
 307                 pr_warning("elf init: internal error\n");
 308                 return -EEXIST;
 309         }
 310
 311         if (obj->efile.obj_buf_sz > 0) {
 312                 /*
 313                  * obj_buf should have been validated by
 314                  * bpf_object__open_buffer().
 315                  */
 316                 obj->efile.elf = elf_memory(obj->efile.obj_buf,
 317                                             obj->efile.obj_buf_sz);
 318         } else {
 319                 obj->efile.fd = open(obj->path, O_RDONLY);
 320                 if (obj->efile.fd < 0) {
 321                         pr_warning("failed to open %s: %s\n", obj->path,
 322                                         strerror(errno));
 323                         return -errno;
 324                 }
 325
 326                 obj->efile.elf = elf_begin(obj->efile.fd,
 327                                 LIBBPF_ELF_C_READ_MMAP,
 328                                 NULL);
 329         }
 330
 331         if (!obj->efile.elf) {
 332                 pr_warning("failed to open %s as ELF file\n",
 333                                 obj->path);
 334                 err = -EINVAL;
 335                 goto errout;
 336         }
 337
 338         if (!gelf_getehdr(obj->efile.elf, &obj->efile.ehdr)) {
 339                 pr_warning("failed to get EHDR from %s\n",
 340                                 obj->path);
 341                 err = -EINVAL;
 342                 goto errout;
 343         }
 344         ep = &obj->efile.ehdr;
 345
 346         if ((ep->e_type != ET_REL) || (ep->e_machine != 0)) {
 347                 pr_warning("%s is not an eBPF object file\n",
 348                         obj->path);
 349                 err = -EINVAL;
 350                 goto errout;
 351         }
 352
 353         return 0;
 354 errout:
 355         bpf_object__elf_finish(obj);
 356         return err;
 357 }
 358
 359 static int
 360 bpf_object__check_endianness(struct bpf_object *obj)
 361 {
 362         static unsigned int const endian = 1;
 363
 364         switch (obj->efile.ehdr.e_ident[EI_DATA]) {
 365         case ELFDATA2LSB:
 366                 /* We are big endian, BPF obj is little endian. */
 367                 if (*(unsigned char const *)&endian != 1)
 368                         goto mismatch;
 369                 break;
 370
 371         case ELFDATA2MSB:
 372                 /* We are little endian, BPF obj is big endian. */
 373                 if (*(unsigned char const *)&endian != 0)
 374                         goto mismatch;
 375                 break;
 376         default:
 377                 return -EINVAL;
 378         }
 379
 380         return 0;
 381
 382 mismatch:
 383         pr_warning("Error: endianness mismatch.\n");
 384         return -EINVAL;
 385 }
 386
 387 static int
 388 bpf_object__init_license(struct bpf_object *obj,
 389                          void *data, size_t size)
 390 {
 391         memcpy(obj->license, data,
 392                min(size, sizeof(obj->license) - 1));
 393         pr_debug("license of %s is %s\n", obj->path, obj->license);
 394         return 0;
 395 }
 396
 397 static int
 398 bpf_object__init_kversion(struct bpf_object *obj,
 399                           void *data, size_t size)
 400 {
 401         u32 kver;
 402
 403         if (size != sizeof(kver)) {
 404                 pr_warning("invalid kver section in %s\n", obj->path);
 405                 return -EINVAL;
 406         }
 407         memcpy(&kver, data, sizeof(kver));
 408         obj->kern_version = kver;
 409         pr_debug("kernel version of %s is %x\n", obj->path,
 410                  obj->kern_version);
 411         return 0;
 412 }
 413
 414 static int
 415 bpf_object__init_maps(struct bpf_object *obj, void *data,
 416                       size_t size)
 417 {
 418         if (size == 0) {
 419                 pr_debug("%s doesn't need map definition\n",
 420                          obj->path);
 421                 return 0;
 422         }
 423
 424         obj->maps_buf = malloc(size);
 425         if (!obj->maps_buf) {
 426                 pr_warning("malloc maps failed: %s\n", obj->path);
 427                 return -ENOMEM;
 428         }
 429
 430         obj->maps_buf_sz = size;
 431         memcpy(obj->maps_buf, data, size);
 432         pr_debug("maps in %s: %ld bytes\n", obj->path, (long)size);
 433         return 0;
 434 }
 435
 436 static int bpf_object__elf_collect(struct bpf_object *obj)
 437 {
 438         Elf *elf = obj->efile.elf;
 439         GElf_Ehdr *ep = &obj->efile.ehdr;
 440         Elf_Scn *scn = NULL;
 441         int idx = 0, err = 0;
 442
 443         /* Elf is corrupted/truncated, avoid calling elf_strptr. */
 444         if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL)) {
 445                 pr_warning("failed to get e_shstrndx from %s\n",
 446                            obj->path);
 447                 return -EINVAL;
 448         }
 449
 450         while ((scn = elf_nextscn(elf, scn)) != NULL) {
 451                 char *name;
 452                 GElf_Shdr sh;
 453                 Elf_Data *data;
 454
 455                 idx++;
 456                 if (gelf_getshdr(scn, &sh) != &sh) {
 457                         pr_warning("failed to get section header from %s\n",
 458                                    obj->path);
 459                         err = -EINVAL;
 460                         goto out;
 461                 }
 462
 463                 name = elf_strptr(elf, ep->e_shstrndx, sh.sh_name);
 464                 if (!name) {
 465                         pr_warning("failed to get section name from %s\n",
 466                                    obj->path);
 467                         err = -EINVAL;
 468                         goto out;
 469                 }
 470
 471                 data = elf_getdata(scn, 0);
 472                 if (!data) {
 473                         pr_warning("failed to get section data from %s(%s)\n",
 474                                    name, obj->path);
 475                         err = -EINVAL;
 476                         goto out;
 477                 }
 478                 pr_debug("section %s, size %ld, link %d, flags %lx, type=%d\n",
 479                          name, (unsigned long)data->d_size,
 480                          (int)sh.sh_link, (unsigned long)sh.sh_flags,
 481                          (int)sh.sh_type);
 482
 483                 if (strcmp(name, "license") == 0)
 484                         err = bpf_object__init_license(obj,
 485                                                        data->d_buf,
 486                                                        data->d_size);
 487                 else if (strcmp(name, "version") == 0)
 488                         err = bpf_object__init_kversion(obj,
 489                                                         data->d_buf,
 490                                                         data->d_size);
 491                 else if (strcmp(name, "maps") == 0)
 492                         err = bpf_object__init_maps(obj, data->d_buf,
 493                                                     data->d_size);
 494                 else if (sh.sh_type == SHT_SYMTAB) {
 495                         if (obj->efile.symbols) {
 496                                 pr_warning("bpf: multiple SYMTAB in %s\n",
 497                                            obj->path);
 498                                 err = -EEXIST;
 499                         } else
 500                                 obj->efile.symbols = data;
 501                 } else if ((sh.sh_type == SHT_PROGBITS) &&
 502                            (sh.sh_flags & SHF_EXECINSTR) &&
 503                            (data->d_size > 0)) {
 504                         err = bpf_object__add_program(obj, data->d_buf,
 505                                                       data->d_size, name, idx);
 506                         if (err) {
 507                                 char errmsg[128];
 508                                 strerror_r(-err, errmsg, sizeof(errmsg));
 509                                 pr_warning("failed to alloc program %s (%s): %s",
 510                                            name, obj->path, errmsg);
 511                         }
 512                 } else if (sh.sh_type == SHT_REL) {
 513                         void *reloc = obj->efile.reloc;
 514                         int nr_reloc = obj->efile.nr_reloc + 1;
 515
 516                         reloc = realloc(reloc,
 517                                         sizeof(*obj->efile.reloc) * nr_reloc);
 518                         if (!reloc) {
 519                                 pr_warning("realloc failed\n");
 520                                 err = -ENOMEM;
 521                         } else {
 522                                 int n = nr_reloc - 1;
 523
 524                                 obj->efile.reloc = reloc;
 525                                 obj->efile.nr_reloc = nr_reloc;
 526
 527                                 obj->efile.reloc[n].shdr = sh;
 528                                 obj->efile.reloc[n].data = data;
 529                         }
 530                 }
 531                 if (err)
 532                         goto out;
 533         }
 534 out:
 535         return err;
 536 }
 537
 538 static struct bpf_program *
 539 bpf_object__find_prog_by_idx(struct bpf_object *obj, int idx)
 540 {
 541         struct bpf_program *prog;
 542         size_t i;
 543
 544         for (i = 0; i < obj->nr_programs; i++) {
 545                 prog = &obj->programs[i];
 546                 if (prog->idx == idx)
 547                         return prog;
 548         }
 549         return NULL;
 550 }
 551
 552 static int
 553 bpf_program__collect_reloc(struct bpf_program *prog,
 554                            size_t nr_maps, GElf_Shdr *shdr,
 555                            Elf_Data *data, Elf_Data *symbols)
 556 {
 557         int i, nrels;
 558
 559         pr_debug("collecting relocating info for: '%s'\n",
 560                  prog->section_name);
 561         nrels = shdr->sh_size / shdr->sh_entsize;
 562
 563         prog->reloc_desc = malloc(sizeof(*prog->reloc_desc) * nrels);
 564         if (!prog->reloc_desc) {
 565                 pr_warning("failed to alloc memory in relocation\n");
 566                 return -ENOMEM;
 567         }
 568         prog->nr_reloc = nrels;
 569
 570         for (i = 0; i < nrels; i++) {
 571                 GElf_Sym sym;
 572                 GElf_Rel rel;
 573                 unsigned int insn_idx;
 574                 struct bpf_insn *insns = prog->insns;
 575                 size_t map_idx;
 576
 577                 if (!gelf_getrel(data, i, &rel)) {
 578                         pr_warning("relocation: failed to get %d reloc\n", i);
 579                         return -EINVAL;
 580                 }
 581
 582                 insn_idx = rel.r_offset / sizeof(struct bpf_insn);
 583                 pr_debug("relocation: insn_idx=%u\n", insn_idx);
 584
 585                 if (!gelf_getsym(symbols,
 586                                  GELF_R_SYM(rel.r_info),
 587                                  &sym)) {
 588                         pr_warning("relocation: symbol %"PRIx64" not found\n",
 589                                    GELF_R_SYM(rel.r_info));
 590                         return -EINVAL;
 591                 }
 592
 593                 if (insns[insn_idx].code != (BPF_LD | BPF_IMM | BPF_DW)) {
 594                         pr_warning("bpf: relocation: invalid relo for insns[%d].code 0x%x\n",
 595                                    insn_idx, insns[insn_idx].code);
 596                         return -EINVAL;
 597                 }
 598
 599                 map_idx = sym.st_value / sizeof(struct bpf_map_def);
 600                 if (map_idx >= nr_maps) {
 601                         pr_warning("bpf relocation: map_idx %d large than %d\n",
 602                                    (int)map_idx, (int)nr_maps - 1);
 603                         return -EINVAL;
 604                 }
 605
 606                 prog->reloc_desc[i].insn_idx = insn_idx;
 607                 prog->reloc_desc[i].map_idx = map_idx;
 608         }
 609         return 0;
 610 }
 611
 612 static int
 613 bpf_object__create_maps(struct bpf_object *obj)
 614 {
 615         unsigned int i;
 616         size_t nr_maps;
 617         int *pfd;
 618
 619         nr_maps = obj->maps_buf_sz / sizeof(struct bpf_map_def);
 620         if (!obj->maps_buf || !nr_maps) {
 621                 pr_debug("don't need create maps for %s\n",
 622                          obj->path);
 623                 return 0;
 624         }
 625
 626         obj->map_fds = malloc(sizeof(int) * nr_maps);
 627         if (!obj->map_fds) {
 628                 pr_warning("realloc perf_bpf_map_fds failed\n");
 629                 return -ENOMEM;
 630         }
 631         obj->nr_map_fds = nr_maps;
 632
 633         /* fill all fd with -1 */
 634         memset(obj->map_fds, -1, sizeof(int) * nr_maps);
 635
 636         pfd = obj->map_fds;
 637         for (i = 0; i < nr_maps; i++) {
 638                 struct bpf_map_def def;
 639
 640                 def = *(struct bpf_map_def *)(obj->maps_buf +
 641                                 i * sizeof(struct bpf_map_def));
 642
 643                 *pfd = bpf_create_map(def.type,
 644                                       def.key_size,
 645                                       def.value_size,
 646                                       def.max_entries);
 647                 if (*pfd < 0) {
 648                         size_t j;
 649                         int err = *pfd;
 650
 651                         pr_warning("failed to create map: %s\n",
 652                                    strerror(errno));
 653                         for (j = 0; j < i; j++)
 654                                 zclose(obj->map_fds[j]);
 655                         obj->nr_map_fds = 0;
 656                         zfree(&obj->map_fds);
 657                         return err;
 658                 }
 659                 pr_debug("create map: fd=%d\n", *pfd);
 660                 pfd++;
 661         }
 662
 663         zfree(&obj->maps_buf);
 664         obj->maps_buf_sz = 0;
 665         return 0;
 666 }
 667
 668 static int
 669 bpf_program__relocate(struct bpf_program *prog, int *map_fds)
 670 {
 671         int i;
 672
 673         if (!prog || !prog->reloc_desc)
 674                 return 0;
 675
 676         for (i = 0; i < prog->nr_reloc; i++) {
 677                 int insn_idx, map_idx;
 678                 struct bpf_insn *insns = prog->insns;
 679
 680                 insn_idx = prog->reloc_desc[i].insn_idx;
 681                 map_idx = prog->reloc_desc[i].map_idx;
 682
 683                 if (insn_idx >= (int)prog->insns_cnt) {
 684                         pr_warning("relocation out of range: '%s'\n",
 685                                    prog->section_name);
 686                         return -ERANGE;
 687                 }
 688                 insns[insn_idx].src_reg = BPF_PSEUDO_MAP_FD;
 689                 insns[insn_idx].imm = map_fds[map_idx];
 690         }
 691
 692         zfree(&prog->reloc_desc);
 693         prog->nr_reloc = 0;
 694         return 0;
 695 }
 696
 697
 698 static int
 699 bpf_object__relocate(struct bpf_object *obj)
 700 {
 701         struct bpf_program *prog;
 702         size_t i;
 703         int err;
 704
 705         for (i = 0; i < obj->nr_programs; i++) {
 706                 prog = &obj->programs[i];
 707
 708                 err = bpf_program__relocate(prog, obj->map_fds);
 709                 if (err) {
 710                         pr_warning("failed to relocate '%s'\n",
 711                                    prog->section_name);
 712                         return err;
 713                 }
 714         }
 715         return 0;
 716 }
 717
 718 static int bpf_object__collect_reloc(struct bpf_object *obj)
 719 {
 720         int i, err;
 721
 722         if (!obj_elf_valid(obj)) {
 723                 pr_warning("Internal error: elf object is closed\n");
 724                 return -EINVAL;
 725         }
 726
 727         for (i = 0; i < obj->efile.nr_reloc; i++) {
 728                 GElf_Shdr *shdr = &obj->efile.reloc[i].shdr;
 729                 Elf_Data *data = obj->efile.reloc[i].data;
 730                 int idx = shdr->sh_info;
 731                 struct bpf_program *prog;
 732                 size_t nr_maps = obj->maps_buf_sz /
 733                                  sizeof(struct bpf_map_def);
 734
 735                 if (shdr->sh_type != SHT_REL) {
 736                         pr_warning("internal error at %d\n", __LINE__);
 737                         return -EINVAL;
 738                 }
 739
 740                 prog = bpf_object__find_prog_by_idx(obj, idx);
 741                 if (!prog) {
 742                         pr_warning("relocation failed: no %d section\n",
 743                                    idx);
 744                         return -ENOENT;
 745                 }
 746
 747                 err = bpf_program__collect_reloc(prog, nr_maps,
 748                                                  shdr, data,
 749                                                  obj->efile.symbols);
 750                 if (err)
 751                         return -EINVAL;
 752         }
 753         return 0;
 754 }
 755
 756 static int
 757 load_program(struct bpf_insn *insns, int insns_cnt,
 758              char *license, u32 kern_version, int *pfd)
 759 {
 760         int ret;
 761         char *log_buf;
 762
 763         if (!insns || !insns_cnt)
 764                 return -EINVAL;
 765
 766         log_buf = malloc(BPF_LOG_BUF_SIZE);
 767         if (!log_buf)
 768                 pr_warning("Alloc log buffer for bpf loader error, continue without log\n");
 769
 770         ret = bpf_load_program(BPF_PROG_TYPE_KPROBE, insns,
 771                                insns_cnt, license, kern_version,
 772                                log_buf, BPF_LOG_BUF_SIZE);
 773
 774         if (ret >= 0) {
 775                 *pfd = ret;
 776                 ret = 0;
 777                 goto out;
 778         }
 779
 780         ret = -EINVAL;
 781         pr_warning("load bpf program failed: %s\n", strerror(errno));
 782
 783         if (log_buf) {
 784                 pr_warning("-- BEGIN DUMP LOG ---\n");
 785                 pr_warning("\n%s\n", log_buf);
 786                 pr_warning("-- END LOG --\n");
 787         }
 788
 789 out:
 790         free(log_buf);
 791         return ret;
 792 }
 793
 794 static int
 795 bpf_program__load(struct bpf_program *prog,
 796                   char *license, u32 kern_version)
 797 {
 798         int err, fd;
 799
 800         err = load_program(prog->insns, prog->insns_cnt,
 801                            license, kern_version, &fd);
 802         if (!err)
 803                 prog->fd = fd;
 804
 805         if (err)
 806                 pr_warning("failed to load program '%s'\n",
 807                            prog->section_name);
 808         zfree(&prog->insns);
 809         prog->insns_cnt = 0;
 810         return err;
 811 }
 812
 813 static int
 814 bpf_object__load_progs(struct bpf_object *obj)
 815 {
 816         size_t i;
 817         int err;
 818
 819         for (i = 0; i < obj->nr_programs; i++) {
 820                 err = bpf_program__load(&obj->programs[i],
 821                                         obj->license,
 822                                         obj->kern_version);
 823                 if (err)
 824                         return err;
 825         }
 826         return 0;
 827 }
 828
 829 static int bpf_object__validate(struct bpf_object *obj)
 830 {
 831         if (obj->kern_version == 0) {
 832                 pr_warning("%s doesn't provide kernel version\n",
 833                            obj->path);
 834                 return -EINVAL;
 835         }
 836         return 0;
 837 }
 838
 839 static struct bpf_object *
 840 __bpf_object__open(const char *path, void *obj_buf, size_t obj_buf_sz)
 841 {
 842         struct bpf_object *obj;
 843
 844         if (elf_version(EV_CURRENT) == EV_NONE) {
 845                 pr_warning("failed to init libelf for %s\n", path);
 846                 return NULL;
 847         }
 848
 849         obj = bpf_object__new(path, obj_buf, obj_buf_sz);
 850         if (!obj)
 851                 return NULL;
 852
 853         if (bpf_object__elf_init(obj))
 854                 goto out;
 855         if (bpf_object__check_endianness(obj))
 856                 goto out;
 857         if (bpf_object__elf_collect(obj))
 858                 goto out;
 859         if (bpf_object__collect_reloc(obj))
 860                 goto out;
 861         if (bpf_object__validate(obj))
 862                 goto out;
 863
 864         bpf_object__elf_finish(obj);
 865         return obj;
 866 out:
 867         bpf_object__close(obj);
 868         return NULL;
 869 }
 870
 871 struct bpf_object *bpf_object__open(const char *path)
 872 {
 873         /* param validation */
 874         if (!path)
 875                 return NULL;
 876
 877         pr_debug("loading %s\n", path);
 878
 879         return __bpf_object__open(path, NULL, 0);
 880 }
 881
 882 struct bpf_object *bpf_object__open_buffer(void *obj_buf,
 883                                            size_t obj_buf_sz)
 884 {
 885         /* param validation */
 886         if (!obj_buf || obj_buf_sz <= 0)
 887                 return NULL;
 888
 889         pr_debug("loading object from buffer\n");
 890
 891         return __bpf_object__open("[buffer]", obj_buf, obj_buf_sz);
 892 }
 893
 894 int bpf_object__unload(struct bpf_object *obj)
 895 {
 896         size_t i;
 897
 898         if (!obj)
 899                 return -EINVAL;
 900
 901         for (i = 0; i < obj->nr_map_fds; i++)
 902                 zclose(obj->map_fds[i]);
 903         zfree(&obj->map_fds);
 904         obj->nr_map_fds = 0;
 905
 906         for (i = 0; i < obj->nr_programs; i++)
 907                 bpf_program__unload(&obj->programs[i]);
 908
 909         return 0;
 910 }
 911
 912 int bpf_object__load(struct bpf_object *obj)
 913 {
 914         if (!obj)
 915                 return -EINVAL;
 916
 917         if (obj->loaded) {
 918                 pr_warning("object should not be loaded twice\n");
 919                 return -EINVAL;
 920         }
 921
 922         obj->loaded = true;
 923         if (bpf_object__create_maps(obj))
 924                 goto out;
 925         if (bpf_object__relocate(obj))
 926                 goto out;
 927         if (bpf_object__load_progs(obj))
 928                 goto out;
 929
 930         return 0;
 931 out:
 932         bpf_object__unload(obj);
 933         pr_warning("failed to load object '%s'\n", obj->path);
 934         return -EINVAL;
 935 }
 936
 937 void bpf_object__close(struct bpf_object *obj)
 938 {
 939         size_t i;
 940
 941         if (!obj)
 942                 return;
 943
 944         bpf_object__elf_finish(obj);
 945         bpf_object__unload(obj);
 946
 947         zfree(&obj->maps_buf);
 948
 949         if (obj->programs && obj->nr_programs) {
 950                 for (i = 0; i < obj->nr_programs; i++)
 951                         bpf_program__exit(&obj->programs[i]);
 952         }
 953         zfree(&obj->programs);
 954
 955         list_del(&obj->list);
 956         free(obj);
 957 }
 958
 959 struct bpf_object *
 960 bpf_object__next(struct bpf_object *prev)
 961 {
 962         struct bpf_object *next;
 963
 964         if (!prev)
 965                 next = list_first_entry(&bpf_objects_list,
 966                                         struct bpf_object,
 967                                         list);
 968         else
 969                 next = list_next_entry(prev, list);
 970
 971         /* Empty list is noticed here so don't need checking on entry. */
 972         if (&next->list == &bpf_objects_list)
 973                 return NULL;
 974
 975         return next;
 976 }
 977
 978 struct bpf_program *
 979 bpf_program__next(struct bpf_program *prev, struct bpf_object *obj)
 980 {
 981         size_t idx;
 982
 983         if (!obj->programs)
 984                 return NULL;
 985         /* First handler */
 986         if (prev == NULL)
 987                 return &obj->programs[0];
 988
 989         if (prev->obj != obj) {
 990                 pr_warning("error: program handler doesn't match object\n");
 991                 return NULL;
 992         }
 993
 994         idx = (prev - obj->programs) + 1;
 995         if (idx >= obj->nr_programs)
 996                 return NULL;
 997         return &obj->programs[idx];
 998 }
 999
1000 int bpf_program__set_private(struct bpf_program *prog,
1001                              void *priv,
1002                              bpf_program_clear_priv_t clear_priv)
1003 {
1004         if (prog->priv && prog->clear_priv)
1005                 prog->clear_priv(prog, prog->priv);
1006
1007         prog->priv = priv;
1008         prog->clear_priv = clear_priv;
1009         return 0;
1010 }
1011
1012 int bpf_program__get_private(struct bpf_program *prog, void **ppriv)
1013 {
1014         *ppriv = prog->priv;
1015         return 0;
1016 }
1017
1018 const char *bpf_program__title(struct bpf_program *prog, bool dup)
1019 {
1020         const char *title;
1021
1022         title = prog->section_name;
1023         if (dup) {
1024                 title = strdup(title);
1025                 if (!title) {
1026                         pr_warning("failed to strdup program title\n");
1027                         return NULL;
1028                 }
1029         }
1030
1031         return title;
1032 }
1033
1034 int bpf_program__fd(struct bpf_program *prog)
1035 {
1036         return prog->fd;
1037 }