lib/bin-info.c

   1 /*
   2  * bin-info.c
   3  *
   4  * Babeltrace - Executable and Shared Object Debug Info Reader
   5  *
   6  * Copyright 2015 Antoine Busque <abusque@efficios.com>
   7  *
   8  * Author: Antoine Busque <abusque@efficios.com>
   9  *
  10  * Permission is hereby granted, free of charge, to any person obtaining a copy
  11  * of this software and associated documentation files (the "Software"), to deal
  12  * in the Software without restriction, including without limitation the rights
  13  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  14  * copies of the Software, and to permit persons to whom the Software is
  15  * furnished to do so, subject to the following conditions:
  16  *
  17  * The above copyright notice and this permission notice shall be included in
  18  * all copies or substantial portions of the Software.
  19  *
  20  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  21  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  23  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  24  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  25  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  26  * SOFTWARE.
  27  */
  28
  29 #include <fcntl.h>
  30 #include <math.h>
  31 #include <libgen.h>
  32 #include <stdio.h>
  33 #include <inttypes.h>
  34 #include <stdlib.h>
  35 #include <string.h>
  36 #include <unistd.h>
  37 #include <dwarf.h>
  38 #include <glib.h>
  39 #include <babeltrace/dwarf.h>
  40 #include <babeltrace/bin-info.h>
  41 #include <babeltrace/crc32.h>
  42 #include <babeltrace/babeltrace-internal.h>
  43 #include <babeltrace/utils.h>
  44
  45 /*
  46  * An address printed in hex is at most 20 bytes (16 for 64-bits +
  47  * leading 0x + optional leading '+' if addr is an offset + null
  48  * character).
  49  */
  50 #define ADDR_STR_LEN 20
  51
  52 BT_HIDDEN
  53 int bin_info_init(void)
  54 {
  55         int ret = 0;
  56
  57         if (elf_version(EV_CURRENT) == EV_NONE) {
  58                 printf_debug("ELF library initialization failed: %s\n",
  59                                 elf_errmsg(-1));
  60                 ret = -1;
  61         }
  62
  63         return ret;
  64 }
  65
  66 BT_HIDDEN
  67 struct bin_info *bin_info_create(const char *path, uint64_t low_addr,
  68                 uint64_t memsz, bool is_pic)
  69 {
  70         struct bin_info *bin = NULL;
  71
  72         if (!path) {
  73                 goto error;
  74         }
  75
  76         bin = g_new0(struct bin_info, 1);
  77         if (!bin) {
  78                 goto error;
  79         }
  80
  81         if (opt_debug_info_target_prefix) {
  82                 bin->elf_path = g_build_path("/", opt_debug_info_target_prefix,
  83                                                 path, NULL);
  84         } else {
  85                 bin->elf_path = strdup(path);
  86         }
  87
  88         if (!bin->elf_path) {
  89                 goto error;
  90         }
  91
  92         bin->is_pic = is_pic;
  93         bin->memsz = memsz;
  94         bin->low_addr = low_addr;
  95         bin->high_addr = bin->low_addr + bin->memsz;
  96
  97         return bin;
  98
  99 error:
 100         bin_info_destroy(bin);
 101         return NULL;
 102 }
 103
 104 BT_HIDDEN
 105 void bin_info_destroy(struct bin_info *bin)
 106 {
 107         if (!bin) {
 108                 return;
 109         }
 110
 111         dwarf_end(bin->dwarf_info);
 112
 113         free(bin->elf_path);
 114         free(bin->dwarf_path);
 115         free(bin->build_id);
 116         free(bin->dbg_link_filename);
 117
 118         elf_end(bin->elf_file);
 119
 120         close(bin->elf_fd);
 121         close(bin->dwarf_fd);
 122
 123         g_free(bin);
 124 }
 125
 126
 127 BT_HIDDEN
 128 int bin_info_set_build_id(struct bin_info *bin, uint8_t *build_id,
 129                 size_t build_id_len)
 130 {
 131         if (!bin || !build_id) {
 132                 goto error;
 133         }
 134
 135         bin->build_id = malloc(build_id_len);
 136         if (!bin->build_id) {
 137                 goto error;
 138         }
 139
 140         memcpy(bin->build_id, build_id, build_id_len);
 141         bin->build_id_len = build_id_len;
 142
 143         /*
 144          * Reset the is_elf_only flag in case it had been set
 145          * previously, because we might find separate debug info using
 146          * the new build id information.
 147          */
 148         bin->is_elf_only = false;
 149
 150         return 0;
 151
 152 error:
 153
 154         return -1;
 155 }
 156
 157 BT_HIDDEN
 158 int bin_info_set_debug_link(struct bin_info *bin, char *filename, uint32_t crc)
 159 {
 160         if (!bin || !filename) {
 161                 goto error;
 162         }
 163
 164         bin->dbg_link_filename = strdup(filename);
 165         if (!bin->dbg_link_filename) {
 166                 goto error;
 167         }
 168
 169         bin->dbg_link_crc = crc;
 170
 171         /*
 172          * Reset the is_elf_only flag in case it had been set
 173          * previously, because we might find separate debug info using
 174          * the new build id information.
 175          */
 176         bin->is_elf_only = false;
 177
 178         return 0;
 179
 180 error:
 181
 182         return -1;
 183 }
 184
 185 /**
 186  * Tries to read DWARF info from the location given by path, and
 187  * attach it to the given bin_info instance if it exists.
 188  *
 189  * @param bin   bin_info instance for which to set DWARF info
 190  * @param path  Presumed location of the DWARF info
 191  * @returns     0 on success, -1 on failure
 192  */
 193 static
 194 int bin_info_set_dwarf_info_from_path(struct bin_info *bin, char *path)
 195 {
 196         int fd = -1, ret = 0;
 197         struct bt_dwarf_cu *cu = NULL;
 198         Dwarf *dwarf_info = NULL;
 199
 200         if (!bin || !path) {
 201                 goto error;
 202         }
 203
 204         fd = open(path, O_RDONLY);
 205         if (fd < 0) {
 206                 goto error;
 207         }
 208
 209         dwarf_info = dwarf_begin(fd, DWARF_C_READ);
 210         if (!dwarf_info) {
 211                 goto error;
 212         }
 213
 214         /*
 215          * Check if the dwarf info has any CU. If not, the
 216          * executable's object file contains no DWARF info.
 217          */
 218         cu = bt_dwarf_cu_create(dwarf_info);
 219         if (!cu) {
 220                 goto error;
 221         }
 222
 223         ret = bt_dwarf_cu_next(cu);
 224         if (ret) {
 225                 goto error;
 226         }
 227
 228         bin->dwarf_fd = fd;
 229         bin->dwarf_path = strdup(path);
 230         if (!bin->dwarf_path) {
 231                 goto error;
 232         }
 233         bin->dwarf_info = dwarf_info;
 234         free(cu);
 235
 236         return 0;
 237
 238 error:
 239         close(fd);
 240         dwarf_end(dwarf_info);
 241         g_free(dwarf_info);
 242         free(cu);
 243
 244         return -1;
 245 }
 246
 247 /**
 248  * Try to set the dwarf_info for a given bin_info instance via the
 249  * build ID method.
 250  *
 251  * @param bin           bin_info instance for which to retrieve the
 252  *                      DWARF info via build ID
 253  * @returns             0 on success (i.e. dwarf_info set), -1 on failure
 254  */
 255 static
 256 int bin_info_set_dwarf_info_build_id(struct bin_info *bin)
 257 {
 258         int i = 0, ret = 0;
 259         char *path = NULL, *build_id_file = NULL;
 260         const char *dbg_dir = NULL;
 261         size_t build_id_file_len;
 262
 263         if (!bin || !bin->build_id) {
 264                 goto error;
 265         }
 266
 267         dbg_dir = opt_debug_info_dir ? : DEFAULT_DEBUG_DIR;
 268
 269         /* 2 characters per byte printed in hex, +1 for '/' and +1 for '\0' */
 270         build_id_file_len = (2 * bin->build_id_len) + 1 +
 271                         strlen(BUILD_ID_SUFFIX) + 1;
 272         build_id_file = malloc(build_id_file_len);
 273         if (!build_id_file) {
 274                 goto error;
 275         }
 276
 277         snprintf(build_id_file, 4, "%02x/", bin->build_id[0]);
 278         for (i = 1; i < bin->build_id_len; ++i) {
 279                 int path_idx = 3 + 2 * (i - 1);
 280
 281                 snprintf(&build_id_file[path_idx], 3, "%02x", bin->build_id[i]);
 282         }
 283         strcat(build_id_file, BUILD_ID_SUFFIX);
 284
 285         path = g_build_path("/", dbg_dir, BUILD_ID_SUBDIR, build_id_file, NULL);
 286         if (!path) {
 287                 goto error;
 288         }
 289
 290         ret = bin_info_set_dwarf_info_from_path(bin, path);
 291         if (ret) {
 292                 goto error;
 293         }
 294
 295         goto end;
 296
 297 error:
 298         ret = -1;
 299 end:
 300         free(build_id_file);
 301         free(path);
 302
 303         return ret;
 304 }
 305
 306 /**
 307  * Tests whether the file located at path exists and has the expected
 308  * checksum.
 309  *
 310  * This predicate is used when looking up separate debug info via the
 311  * GNU debuglink method. The expected crc can be found .gnu_debuglink
 312  * section in the original ELF file, along with the filename for the
 313  * file containing the debug info.
 314  *
 315  * @param path  Full path at which to look for the debug file
 316  * @param crc   Expected checksum for the debug file
 317  * @returns     1 if the file exists and has the correct checksum,
 318  *              0 otherwise
 319  */
 320 static
 321 int is_valid_debug_file(char *path, uint32_t crc)
 322 {
 323         int ret = 0, fd = -1;
 324         uint32_t _crc = 0;
 325
 326         if (!path) {
 327                 goto end;
 328         }
 329
 330         fd = open(path, O_RDONLY);
 331         if (fd < 0) {
 332                 goto end;
 333         }
 334
 335         ret = crc32(fd, &_crc);
 336         if (ret) {
 337                 ret = 0;
 338                 goto end;
 339         }
 340
 341         ret = (crc == _crc);
 342
 343 end:
 344         close(fd);
 345         return ret;
 346 }
 347
 348 /**
 349  * Try to set the dwarf_info for a given bin_info instance via the
 350  * build ID method.
 351  *
 352  * @param bin           bin_info instance for which to retrieve the
 353  *                      DWARF info via debug link
 354  * @returns             0 on success (i.e. dwarf_info set), -1 on failure
 355  */
 356 static
 357 int bin_info_set_dwarf_info_debug_link(struct bin_info *bin)
 358 {
 359         int ret = 0;
 360         const char *dbg_dir = NULL;
 361         char *dir_name = NULL, *bin_dir = NULL, *path = NULL;
 362         size_t max_path_len = 0;
 363
 364         if (!bin || !bin->dbg_link_filename) {
 365                 goto error;
 366         }
 367
 368         dbg_dir = opt_debug_info_dir ? : DEFAULT_DEBUG_DIR;
 369
 370         dir_name = dirname(bin->elf_path);
 371         if (!dir_name) {
 372                 goto error;
 373         }
 374
 375         /* bin_dir is just dir_name with a trailing slash */
 376         bin_dir = malloc(strlen(dir_name) + 2);
 377         if (!bin_dir) {
 378                 goto error;
 379         }
 380
 381         strcpy(bin_dir, dir_name);
 382         strcat(bin_dir, "/");
 383
 384         max_path_len = strlen(dbg_dir) + strlen(bin_dir) +
 385                         strlen(DEBUG_SUBDIR) + strlen(bin->dbg_link_filename)
 386                         + 1;
 387         path = malloc(max_path_len);
 388         if (!path) {
 389                 goto error;
 390         }
 391
 392         /* First look in the executable's dir */
 393         strcpy(path, bin_dir);
 394         strcat(path, bin->dbg_link_filename);
 395
 396         if (is_valid_debug_file(path, bin->dbg_link_crc)) {
 397                 goto found;
 398         }
 399
 400         /* If not found, look in .debug subdir */
 401         strcpy(path, bin_dir);
 402         strcat(path, DEBUG_SUBDIR);
 403         strcat(path, bin->dbg_link_filename);
 404
 405         if (is_valid_debug_file(path, bin->dbg_link_crc)) {
 406                 goto found;
 407         }
 408
 409         /* Lastly, look under the global debug directory */
 410         strcpy(path, dbg_dir);
 411         strcat(path, bin_dir);
 412         strcat(path, bin->dbg_link_filename);
 413
 414         if (is_valid_debug_file(path, bin->dbg_link_crc)) {
 415                 goto found;
 416         }
 417
 418 error:
 419         ret = -1;
 420 end:
 421         free(path);
 422         free(bin_dir);
 423
 424         return ret;
 425
 426 found:
 427         ret = bin_info_set_dwarf_info_from_path(bin, path);
 428         if (ret) {
 429                 goto error;
 430         }
 431
 432         goto end;
 433 }
 434
 435 /**
 436  * Initialize the DWARF info for a given executable.
 437  *
 438  * @param bin   bin_info instance
 439  * @returns     0 on success, -1 on failure
 440  */
 441 static
 442 int bin_info_set_dwarf_info(struct bin_info *bin)
 443 {
 444         int ret = 0;
 445
 446         if (!bin) {
 447                 goto error;
 448         }
 449
 450         /* First try to set the DWARF info from the ELF file */
 451         ret = bin_info_set_dwarf_info_from_path(bin, bin->elf_path);
 452         if (!ret) {
 453                 goto end;
 454         }
 455
 456         /*
 457          * If that fails, try to find separate debug info via build ID
 458          * and debug link.
 459          */
 460         ret = bin_info_set_dwarf_info_build_id(bin);
 461         if (!ret) {
 462                 goto end;
 463         }
 464
 465         ret = bin_info_set_dwarf_info_debug_link(bin);
 466         if (!ret) {
 467                 goto end;
 468         }
 469
 470 error:
 471         ret = -1;
 472 end:
 473         return ret;
 474 }
 475
 476 /**
 477  * Initialize the ELF file for a given executable.
 478  *
 479  * @param bin   bin_info instance
 480  * @returns     0 on success, -1 on failure
 481  */
 482 static
 483 int bin_info_set_elf_file(struct bin_info *bin)
 484 {
 485         int elf_fd;
 486         Elf *elf_file = NULL;
 487
 488         if (!bin) {
 489                 goto error;
 490         }
 491
 492         elf_fd = open(bin->elf_path, O_RDONLY);
 493         if (elf_fd < 0) {
 494                 printf_verbose("Failed to open %s\n", bin->elf_path);
 495                 goto error;
 496         }
 497
 498         elf_file = elf_begin(elf_fd, ELF_C_READ, NULL);
 499         if (!elf_file) {
 500                 printf_debug("elf_begin failed: %s\n", elf_errmsg(-1));
 501                 goto error;
 502         }
 503
 504         if (elf_kind(elf_file) != ELF_K_ELF) {
 505                 printf_verbose("Error: %s is not an ELF object\n",
 506                                 bin->elf_path);
 507                 goto error;
 508         }
 509
 510         bin->elf_fd = elf_fd;
 511         bin->elf_file = elf_file;
 512         return 0;
 513
 514 error:
 515         close(elf_fd);
 516         elf_end(elf_file);
 517         return -1;
 518 }
 519
 520
 521 BT_HIDDEN
 522 void source_location_destroy(struct source_location *src_loc)
 523 {
 524         if (!src_loc) {
 525                 return;
 526         }
 527
 528         free(src_loc->filename);
 529         g_free(src_loc);
 530 }
 531 /**
 532  * Append a string representation of an address offset to an existing
 533  * string.
 534  *
 535  * On success, the out parameter `result` will contain the base string
 536  * followed by the offset string of the form "+0x1234". On failure,
 537  * `result` remains unchanged.
 538  *
 539  * @param base_str      The string to which to append an offset string
 540  * @param low_addr      The lower virtual memory address, the base from
 541  *                      which the offset is computed
 542  * @param high_addr     The higher virtual memory address
 543  * @param result        Out parameter, the base string followed by the
 544  *                      offset string
 545  * @returns             0 on success, -1 on failure
 546  */
 547 static
 548 int bin_info_append_offset_str(const char *base_str, uint64_t low_addr,
 549                                 uint64_t high_addr, char **result)
 550 {
 551         int ret;
 552         uint64_t offset;
 553         char *_result = NULL;
 554         char offset_str[ADDR_STR_LEN];
 555
 556         if (!base_str || !result) {
 557                 goto error;
 558         }
 559
 560         offset = high_addr - low_addr;
 561
 562         _result = malloc(strlen(base_str) + ADDR_STR_LEN);
 563         if (!_result) {
 564                 goto error;
 565         }
 566
 567         ret = snprintf(offset_str, ADDR_STR_LEN, "+%#0" PRIx64, offset);
 568         if (ret < 0) {
 569                 goto error;
 570         }
 571         strcpy(_result, base_str);
 572         strcat(_result, offset_str);
 573         *result = _result;
 574
 575         return 0;
 576
 577 error:
 578         free(_result);
 579         return -1;
 580 }
 581
 582 /**
 583  * Try to find the symbol closest to an address within a given ELF
 584  * section.
 585  *
 586  * Only function symbols are taken into account. The symbol's address
 587  * must precede `addr`. A symbol with a closer address might exist
 588  * after `addr` but is irrelevant because it cannot encompass `addr`.
 589  *
 590  * On success, if found, the out parameters `sym` and `shdr` are
 591  * set. On failure or if none are found, they remain unchanged.
 592  *
 593  * @param scn           ELF section in which to look for the address
 594  * @param addr          Virtual memory address for which to find the
 595  *                      nearest function symbol
 596  * @param sym           Out parameter, the nearest function symbol
 597  * @param shdr          Out parameter, the section header for scn
 598  * @returns             0 on success, -1 on failure
 599  */
 600 static
 601 int bin_info_get_nearest_symbol_from_section(Elf_Scn *scn, uint64_t addr,
 602                 GElf_Sym **sym, GElf_Shdr **shdr)
 603 {
 604         int i;
 605         size_t symbol_count;
 606         Elf_Data *data = NULL;
 607         GElf_Shdr *_shdr = NULL;
 608         GElf_Sym *nearest_sym = NULL;
 609
 610         if (!scn || !sym || !shdr) {
 611                 goto error;
 612         }
 613
 614         _shdr = g_new0(GElf_Shdr, 1);
 615         if (!_shdr) {
 616                 goto error;
 617         }
 618
 619         _shdr = gelf_getshdr(scn, _shdr);
 620         if (!_shdr) {
 621                 goto error;
 622         }
 623
 624         if (_shdr->sh_type != SHT_SYMTAB) {
 625                 /*
 626                  * We are only interested in symbol table (symtab)
 627                  * sections, skip this one.
 628                  */
 629                 goto end;
 630         }
 631
 632         data = elf_getdata(scn, NULL);
 633         if (!data) {
 634                 goto error;
 635         }
 636
 637         symbol_count = _shdr->sh_size / _shdr->sh_entsize;
 638
 639         for (i = 0; i < symbol_count; ++i) {
 640                 GElf_Sym *cur_sym = NULL;
 641
 642                 cur_sym = g_new0(GElf_Sym, 1);
 643                 if (!cur_sym) {
 644                         goto error;
 645                 }
 646                 cur_sym = gelf_getsym(data, i, cur_sym);
 647                 if (!cur_sym) {
 648                         goto error;
 649                 }
 650                 if (GELF_ST_TYPE(cur_sym->st_info) != STT_FUNC) {
 651                         /* We're only interested in the functions. */
 652                         g_free(cur_sym);
 653                         continue;
 654                 }
 655
 656                 if (cur_sym->st_value <= addr &&
 657                                 (!nearest_sym ||
 658                                 cur_sym->st_value > nearest_sym->st_value)) {
 659                         g_free(nearest_sym);
 660                         nearest_sym = cur_sym;
 661                 } else {
 662                         g_free(cur_sym);
 663                 }
 664         }
 665
 666 end:
 667         if (nearest_sym) {
 668                 *sym = nearest_sym;
 669                 *shdr = _shdr;
 670         } else {
 671                 g_free(_shdr);
 672         }
 673
 674         return 0;
 675
 676 error:
 677         g_free(nearest_sym);
 678         g_free(_shdr);
 679         return -1;
 680 }
 681
 682 /**
 683  * Get the name of the function containing a given address within an
 684  * executable using ELF symbols.
 685  *
 686  * The function name is in fact the name of the nearest ELF symbol,
 687  * followed by the offset in bytes between the address and the symbol
 688  * (in hex), separated by a '+' character.
 689  *
 690  * If found, the out parameter `func_name` is set on success. On failure,
 691  * it remains unchanged.
 692  *
 693  * @param bin           bin_info instance for the executable containing
 694  *                      the address
 695  * @param addr          Virtual memory address for which to find the
 696  *                      function name
 697  * @param func_name     Out parameter, the function name
 698  * @returns             0 on success, -1 on failure
 699  */
 700 static
 701 int bin_info_lookup_elf_function_name(struct bin_info *bin, uint64_t addr,
 702                 char **func_name)
 703 {
 704         /*
 705          * TODO (possible optimisation): if an ELF has no symtab
 706          * section, it has been stripped. Therefore, it would be wise
 707          * to store a flag indicating the stripped status after the
 708          * first iteration to prevent subsequent ones.
 709          */
 710         int ret = 0;
 711         Elf_Scn *scn = NULL;
 712         GElf_Sym *sym = NULL;
 713         GElf_Shdr *shdr = NULL;
 714         char *sym_name = NULL;
 715
 716         /* Set ELF file if it hasn't been accessed yet. */
 717         if (!bin->elf_file) {
 718                 ret = bin_info_set_elf_file(bin);
 719                 if (ret) {
 720                         /* Failed to set ELF file. */
 721                         goto error;
 722                 }
 723         }
 724
 725         scn = elf_nextscn(bin->elf_file, scn);
 726         if (!scn) {
 727                 goto error;
 728         }
 729
 730         while (scn && !sym) {
 731                 ret = bin_info_get_nearest_symbol_from_section(
 732                                 scn, addr, &sym, &shdr);
 733                 if (ret) {
 734                         goto error;
 735                 }
 736
 737                 scn = elf_nextscn(bin->elf_file, scn);
 738         }
 739
 740         if (sym) {
 741                 sym_name = elf_strptr(bin->elf_file, shdr->sh_link,
 742                                 sym->st_name);
 743                 if (!sym_name) {
 744                         goto error;
 745                 }
 746
 747                 ret = bin_info_append_offset_str(sym_name, sym->st_value, addr,
 748                                                 func_name);
 749                 if (ret) {
 750                         goto error;
 751                 }
 752         }
 753
 754         g_free(shdr);
 755         g_free(sym);
 756         return 0;
 757
 758 error:
 759         g_free(shdr);
 760         g_free(sym);
 761         return -1;
 762 }
 763
 764 /**
 765  * Get the name of the function containing a given address within a
 766  * given compile unit (CU).
 767  *
 768  * If found, the out parameter `func_name` is set on success. On
 769  * failure, it remains unchanged.
 770  *
 771  * @param cu            bt_dwarf_cu instance which may contain the address
 772  * @param addr          Virtual memory address for which to find the
 773  *                      function name
 774  * @param func_name     Out parameter, the function name
 775  * @returns             0 on success, -1 on failure
 776  */
 777 static
 778 int bin_info_lookup_cu_function_name(struct bt_dwarf_cu *cu, uint64_t addr,
 779                 char **func_name)
 780 {
 781         int ret = 0;
 782         bool found = false;
 783         struct bt_dwarf_die *die = NULL;
 784
 785         if (!cu || !func_name) {
 786                 goto error;
 787         }
 788
 789         die = bt_dwarf_die_create(cu);
 790         if (!die) {
 791                 goto error;
 792         }
 793
 794         while (bt_dwarf_die_next(die) == 0) {
 795                 int tag;
 796
 797                 ret = bt_dwarf_die_get_tag(die, &tag);
 798                 if (ret) {
 799                         goto error;
 800                 }
 801
 802                 if (tag == DW_TAG_subprogram) {
 803                         ret = bt_dwarf_die_contains_addr(die, addr, &found);
 804                         if (ret) {
 805                                 goto error;
 806                         }
 807
 808                         if (found) {
 809                                 break;
 810                         }
 811                 }
 812         }
 813
 814         if (found) {
 815                 uint64_t low_addr = 0;
 816                 char *die_name = NULL;
 817
 818                 ret = bt_dwarf_die_get_name(die, &die_name);
 819                 if (ret) {
 820                         goto error;
 821                 }
 822
 823                 ret = dwarf_lowpc(die->dwarf_die, &low_addr);
 824                 if (ret) {
 825                         goto error;
 826                 }
 827
 828                 ret = bin_info_append_offset_str(die_name, low_addr, addr,
 829                                                 func_name);
 830                 if (ret) {
 831                         goto error;
 832                 }
 833         }
 834
 835         bt_dwarf_die_destroy(die);
 836         return 0;
 837
 838 error:
 839         bt_dwarf_die_destroy(die);
 840         return -1;
 841 }
 842
 843 /**
 844  * Get the name of the function containing a given address within an
 845  * executable using DWARF debug info.
 846  *
 847  * If found, the out parameter `func_name` is set on success. On
 848  * failure, it remains unchanged.
 849  *
 850  * @param bin           bin_info instance for the executable containing
 851  *                      the address
 852  * @param addr          Virtual memory address for which to find the
 853  *                      function name
 854  * @param func_name     Out parameter, the function name
 855  * @returns             0 on success, -1 on failure
 856  */
 857 static
 858 int bin_info_lookup_dwarf_function_name(struct bin_info *bin, uint64_t addr,
 859                 char **func_name)
 860 {
 861         int ret = 0;
 862         char *_func_name = NULL;
 863         struct bt_dwarf_cu *cu = NULL;
 864
 865         if (!bin || !func_name) {
 866                 goto error;
 867         }
 868
 869         cu = bt_dwarf_cu_create(bin->dwarf_info);
 870         if (!cu) {
 871                 goto error;
 872         }
 873
 874         while (bt_dwarf_cu_next(cu) == 0) {
 875                 ret = bin_info_lookup_cu_function_name(cu, addr, &_func_name);
 876                 if (ret) {
 877                         goto error;
 878                 }
 879
 880                 if (_func_name) {
 881                         break;
 882                 }
 883         }
 884
 885         if (_func_name) {
 886                 *func_name = _func_name;
 887         } else {
 888                 goto error;
 889         }
 890
 891         bt_dwarf_cu_destroy(cu);
 892         return 0;
 893
 894 error:
 895         bt_dwarf_cu_destroy(cu);
 896         return -1;
 897 }
 898
 899 BT_HIDDEN
 900 int bin_info_lookup_function_name(struct bin_info *bin, uint64_t addr,
 901                 char **func_name)
 902 {
 903         int ret = 0;
 904         char *_func_name = NULL;
 905
 906         if (!bin || !func_name) {
 907                 goto error;
 908         }
 909
 910         /* Set DWARF info if it hasn't been accessed yet. */
 911         if (!bin->dwarf_info && !bin->is_elf_only) {
 912                 ret = bin_info_set_dwarf_info(bin);
 913                 if (ret) {
 914                         /* Failed to set DWARF info, fallback to ELF. */
 915                         bin->is_elf_only = true;
 916                 }
 917         }
 918
 919         if (!bin_info_has_address(bin, addr)) {
 920                 goto error;
 921         }
 922
 923         /*
 924          * Addresses in ELF and DWARF are relative to base address for
 925          * PIC, so make the address argument relative too if needed.
 926          */
 927         if (bin->is_pic) {
 928                 addr -= bin->low_addr;
 929         }
 930
 931         if (bin->is_elf_only) {
 932                 ret = bin_info_lookup_elf_function_name(bin, addr, &_func_name);
 933         } else {
 934                 ret = bin_info_lookup_dwarf_function_name(bin, addr, &_func_name);
 935         }
 936
 937         if (ret || !_func_name) {
 938                 goto error;
 939         }
 940
 941         *func_name = _func_name;
 942         return 0;
 943
 944 error:
 945         return -1;
 946 }
 947
 948 BT_HIDDEN
 949 int bin_info_get_bin_loc(struct bin_info *bin, uint64_t addr, char **bin_loc)
 950 {
 951         int ret = 0;
 952         char *_bin_loc = NULL;
 953
 954         if (!bin || !bin_loc) {
 955                 goto error;
 956         }
 957
 958         if (bin->is_pic) {
 959                 addr -= bin->low_addr;
 960                 ret = asprintf(&_bin_loc, "+%#0" PRIx64, addr);
 961         } else {
 962                 ret = asprintf(&_bin_loc, "@%#0" PRIx64, addr);
 963         }
 964
 965         if (ret == -1 || !_bin_loc) {
 966                 goto error;
 967         }
 968
 969         *bin_loc = _bin_loc;
 970         return 0;
 971
 972 error:
 973         return -1;
 974 }
 975
 976 /**
 977  * Predicate used to determine whether the children of a given DIE
 978  * contain a specific address.
 979  *
 980  * More specifically, the parameter `die` is expected to be a
 981  * subprogram (function) DIE, and this predicate tells whether any
 982  * subroutines are inlined within this function and would contain
 983  * `addr`.
 984  *
 985  * On success, the out parameter `contains` is set with the boolean
 986  * value indicating whether the DIE's range covers `addr`. On failure,
 987  * it remains unchanged.
 988  *
 989  * Do note that this function advances the position of `die`. If the
 990  * address is found within one of its children, `die` will be pointing
 991  * to that child upon returning from the function, allowing to extract
 992  * the information deemed necessary.
 993  *
 994  * @param die           The parent DIE in whose children the address will be
 995  *                      looked for
 996  * @param addr          The address for which to look for in the DIEs
 997  * @param contains      Out parameter, true if addr is contained,
 998  *                      false if not
 999  * @returns             Returns 0 on success, -1 on failure
1000  */
1001 static
1002 int bin_info_child_die_has_address(struct bt_dwarf_die *die, uint64_t addr, bool *contains)
1003 {
1004         int ret = 0;
1005         bool _contains = false;
1006
1007         if (!die) {
1008                 goto error;
1009         }
1010
1011         ret = bt_dwarf_die_child(die);
1012         if (ret) {
1013                 goto error;
1014         }
1015
1016         do {
1017                 int tag;
1018
1019                 ret = bt_dwarf_die_get_tag(die, &tag);
1020                 if (ret) {
1021                         goto error;
1022                 }
1023
1024                 if (tag == DW_TAG_inlined_subroutine) {
1025                         ret = bt_dwarf_die_contains_addr(die, addr, &_contains);
1026                         if (ret) {
1027                                 goto error;
1028                         }
1029
1030                         if (contains) {
1031                                 goto end;
1032                         }
1033                 }
1034         } while (bt_dwarf_die_next(die) == 0);
1035
1036 end:
1037         *contains = _contains;
1038         return 0;
1039
1040 error:
1041         return -1;
1042 }
1043
1044 /**
1045  * Lookup the source location for a given address within a CU, making
1046  * the assumption that it is contained within an inline routine in a
1047  * function.
1048  *
1049  * @param cu            bt_dwarf_cu instance in which to look for the address
1050  * @param addr          The address for which to look for
1051  * @param src_loc       Out parameter, the source location (filename and
1052  *                      line number) for the address
1053  * @returns             0 on success, -1 on failure
1054  */
1055 static
1056 int bin_info_lookup_cu_src_loc_inl(struct bt_dwarf_cu *cu, uint64_t addr,
1057                 struct source_location **src_loc)
1058 {
1059         int ret = 0;
1060         bool found = false;
1061         struct bt_dwarf_die *die = NULL;
1062         struct source_location *_src_loc = NULL;
1063
1064         if (!cu || !src_loc) {
1065                 goto error;
1066         }
1067
1068         die = bt_dwarf_die_create(cu);
1069         if (!die) {
1070                 goto error;
1071         }
1072
1073         while (bt_dwarf_die_next(die) == 0) {
1074                 int tag;
1075
1076                 ret = bt_dwarf_die_get_tag(die, &tag);
1077                 if (ret) {
1078                         goto error;
1079                 }
1080
1081                 if (tag == DW_TAG_subprogram) {
1082                         bool contains = false;
1083
1084                         ret = bt_dwarf_die_contains_addr(die, addr, &contains);
1085                         if (ret) {
1086                                 goto error;
1087                         }
1088
1089                         if (contains) {
1090                                 /*
1091                                  * Try to find an inlined subroutine
1092                                  * child of this DIE containing addr.
1093                                  */
1094                                 ret = bin_info_child_die_has_address(die, addr,
1095                                                 &found);
1096                                 if(ret) {
1097                                         goto error;
1098                                 }
1099
1100                                 goto end;
1101                         }
1102                 }
1103         }
1104
1105 end:
1106         if (found) {
1107                 char *filename = NULL;
1108                 uint64_t line_no;
1109
1110                 _src_loc = g_new0(struct source_location, 1);
1111                 if (!_src_loc) {
1112                         goto error;
1113                 }
1114
1115                 ret = bt_dwarf_die_get_call_file(die, &filename);
1116                 if (ret) {
1117                         goto error;
1118                 }
1119                 ret = bt_dwarf_die_get_call_line(die, &line_no);
1120                 if (ret) {
1121                         free(filename);
1122                         goto error;
1123                 }
1124
1125                 _src_loc->filename = filename;
1126                 _src_loc->line_no = line_no;
1127                 *src_loc = _src_loc;
1128         }
1129
1130         bt_dwarf_die_destroy(die);
1131         return 0;
1132
1133 error:
1134         source_location_destroy(_src_loc);
1135         bt_dwarf_die_destroy(die);
1136         return -1;
1137 }
1138
1139 /**
1140  * Lookup the source location for a given address within a CU,
1141  * assuming that it is contained within an inlined function.
1142  *
1143  * A source location can be found regardless of inlining status for
1144  * this method, but in the case of an inlined function, the returned
1145  * source location will point not to the callsite but rather to the
1146  * definition site of the inline function.
1147  *
1148  * @param cu            bt_dwarf_cu instance in which to look for the address
1149  * @param addr          The address for which to look for
1150  * @param src_loc       Out parameter, the source location (filename and
1151  *                      line number) for the address
1152  * @returns             0 on success, -1 on failure
1153  */
1154 static
1155 int bin_info_lookup_cu_src_loc_no_inl(struct bt_dwarf_cu *cu, uint64_t addr,
1156                 struct source_location **src_loc)
1157 {
1158         struct source_location *_src_loc = NULL;
1159         struct bt_dwarf_die *die = NULL;
1160         const char *filename = NULL;
1161         Dwarf_Line *line = NULL;
1162         Dwarf_Addr line_addr;
1163         int ret, line_no;
1164
1165         if (!cu || !src_loc) {
1166                 goto error;
1167         }
1168
1169         die = bt_dwarf_die_create(cu);
1170         if (!die) {
1171                 goto error;
1172         }
1173
1174         line = dwarf_getsrc_die(die->dwarf_die, addr);
1175         if (!line) {
1176                 goto error;
1177         }
1178
1179         ret = dwarf_lineaddr(line, &line_addr);
1180         if (ret) {
1181                 goto error;
1182         }
1183
1184         filename = dwarf_linesrc(line, NULL, NULL);
1185         if (!filename) {
1186                 goto error;
1187         }
1188
1189         if (addr == line_addr) {
1190                 _src_loc = g_new0(struct source_location, 1);
1191                 if (!_src_loc) {
1192                         goto error;
1193                 }
1194
1195                 ret = dwarf_lineno(line, &line_no);
1196                 if (ret) {
1197                         goto error;
1198                 }
1199
1200                 _src_loc->line_no = line_no;
1201                 _src_loc->filename = strdup(filename);
1202         }
1203
1204         bt_dwarf_die_destroy(die);
1205
1206         if (_src_loc) {
1207                 *src_loc = _src_loc;
1208         }
1209
1210         return 0;
1211
1212 error:
1213         source_location_destroy(_src_loc);
1214         bt_dwarf_die_destroy(die);
1215         return -1;
1216 }
1217
1218 /**
1219  * Get the source location (file name and line number) for a given
1220  * address within a compile unit (CU).
1221  *
1222  * On success, the out parameter `src_loc` is set if found. On
1223  * failure, it remains unchanged.
1224  *
1225  * @param cu            bt_dwarf_cu instance for the compile unit which
1226  *                      may contain the address
1227  * @param addr          Virtual memory address for which to find the
1228  *                      source location
1229  * @param src_loc       Out parameter, the source location
1230  * @returns             0 on success, -1 on failure
1231  */
1232 static
1233 int bin_info_lookup_cu_src_loc(struct bt_dwarf_cu *cu, uint64_t addr,
1234                 struct source_location **src_loc)
1235 {
1236         int ret = 0;
1237         struct source_location *_src_loc = NULL;
1238
1239         if (!cu || !src_loc) {
1240                 goto error;
1241         }
1242
1243         ret = bin_info_lookup_cu_src_loc_inl(cu, addr, &_src_loc);
1244         if (ret) {
1245                 goto error;
1246         }
1247
1248         if (_src_loc) {
1249                 goto end;
1250         }
1251
1252         ret = bin_info_lookup_cu_src_loc_no_inl(cu, addr, &_src_loc);
1253         if (ret) {
1254                 goto error;
1255         }
1256
1257         if (_src_loc) {
1258                 goto end;
1259         }
1260
1261 end:
1262         if (_src_loc) {
1263                 *src_loc = _src_loc;
1264         }
1265
1266         return 0;
1267
1268 error:
1269         source_location_destroy(_src_loc);
1270         return -1;
1271 }
1272
1273 BT_HIDDEN
1274 int bin_info_lookup_source_location(struct bin_info *bin, uint64_t addr,
1275                 struct source_location **src_loc)
1276 {
1277         struct bt_dwarf_cu *cu = NULL;
1278         struct source_location *_src_loc = NULL;
1279
1280         if (!bin || !src_loc) {
1281                 goto error;
1282         }
1283
1284         /* Set DWARF info if it hasn't been accessed yet. */
1285         if (!bin->dwarf_info && !bin->is_elf_only) {
1286                 if (bin_info_set_dwarf_info(bin)) {
1287                         /* Failed to set DWARF info. */
1288                         bin->is_elf_only = true;
1289                 }
1290         }
1291
1292         if (bin->is_elf_only) {
1293                 /* We cannot lookup source location without DWARF info. */
1294                 goto error;
1295         }
1296
1297         if (!bin_info_has_address(bin, addr)) {
1298                 goto error;
1299         }
1300
1301         /*
1302          * Addresses in ELF and DWARF are relative to base address for
1303          * PIC, so make the address argument relative too if needed.
1304          */
1305         if (bin->is_pic) {
1306                 addr -= bin->low_addr;
1307         }
1308
1309         cu = bt_dwarf_cu_create(bin->dwarf_info);
1310         if (!cu) {
1311                 goto error;
1312         }
1313
1314         while (bt_dwarf_cu_next(cu) == 0) {
1315                 int ret;
1316
1317                 ret = bin_info_lookup_cu_src_loc(cu, addr, &_src_loc);
1318                 if (ret) {
1319                         goto error;
1320                 }
1321
1322                 if (_src_loc) {
1323                         break;
1324                 }
1325         }
1326
1327         bt_dwarf_cu_destroy(cu);
1328         if (_src_loc) {
1329                 *src_loc = _src_loc;
1330         }
1331
1332         return 0;
1333
1334 error:
1335         source_location_destroy(_src_loc);
1336         bt_dwarf_cu_destroy(cu);
1337         return -1;
1338 }