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