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 #include <errno.h>
  45
  46 /*
  47  * An address printed in hex is at most 20 bytes (16 for 64-bits +
  48  * leading 0x + optional leading '+' if addr is an offset + null
  49  * character).
  50  */
  51 #define ADDR_STR_LEN 20
  52
  53 BT_HIDDEN
  54 int bin_info_init(void)
  55 {
  56         int ret = 0;
  57
  58         if (elf_version(EV_CURRENT) == EV_NONE) {
  59                 printf_debug("ELF library initialization failed: %s\n",
  60                                 elf_errmsg(-1));
  61                 ret = -1;
  62         }
  63
  64         return ret;
  65 }
  66
  67 BT_HIDDEN
  68 struct bin_info *bin_info_create(const char *path, uint64_t low_addr,
  69                 uint64_t memsz, bool is_pic)
  70 {
  71         struct bin_info *bin = NULL;
  72
  73         if (!path) {
  74                 goto error;
  75         }
  76
  77         bin = g_new0(struct bin_info, 1);
  78         if (!bin) {
  79                 goto error;
  80         }
  81
  82         if (opt_debug_info_target_prefix) {
  83                 bin->elf_path = g_build_path("/", opt_debug_info_target_prefix,
  84                                                 path, NULL);
  85         } else {
  86                 bin->elf_path = strdup(path);
  87         }
  88
  89         if (!bin->elf_path) {
  90                 goto error;
  91         }
  92
  93         bin->is_pic = is_pic;
  94         bin->memsz = memsz;
  95         bin->low_addr = low_addr;
  96         bin->high_addr = bin->low_addr + bin->memsz;
  97
  98         return bin;
  99
 100 error:
 101         bin_info_destroy(bin);
 102         return NULL;
 103 }
 104
 105 BT_HIDDEN
 106 void bin_info_destroy(struct bin_info *bin)
 107 {
 108         if (!bin) {
 109                 return;
 110         }
 111
 112         dwarf_end(bin->dwarf_info);
 113
 114         free(bin->elf_path);
 115         free(bin->dwarf_path);
 116         free(bin->build_id);
 117         free(bin->dbg_link_filename);
 118
 119         elf_end(bin->elf_file);
 120
 121         close(bin->elf_fd);
 122         close(bin->dwarf_fd);
 123
 124         g_free(bin);
 125 }
 126
 127
 128 BT_HIDDEN
 129 int bin_info_set_build_id(struct bin_info *bin, uint8_t *build_id,
 130                 size_t build_id_len)
 131 {
 132         if (!bin || !build_id) {
 133                 goto error;
 134         }
 135
 136         bin->build_id = malloc(build_id_len);
 137         if (!bin->build_id) {
 138                 goto error;
 139         }
 140
 141         memcpy(bin->build_id, build_id, build_id_len);
 142         bin->build_id_len = build_id_len;
 143
 144         /*
 145          * Reset the is_elf_only flag in case it had been set
 146          * previously, because we might find separate debug info using
 147          * the new build id information.
 148          */
 149         bin->is_elf_only = false;
 150
 151         return 0;
 152
 153 error:
 154
 155         return -1;
 156 }
 157
 158 BT_HIDDEN
 159 int bin_info_set_debug_link(struct bin_info *bin, char *filename, uint32_t crc)
 160 {
 161         if (!bin || !filename) {
 162                 goto error;
 163         }
 164
 165         bin->dbg_link_filename = strdup(filename);
 166         if (!bin->dbg_link_filename) {
 167                 goto error;
 168         }
 169
 170         bin->dbg_link_crc = crc;
 171
 172         /*
 173          * Reset the is_elf_only flag in case it had been set
 174          * previously, because we might find separate debug info using
 175          * the new build id information.
 176          */
 177         bin->is_elf_only = false;
 178
 179         return 0;
 180
 181 error:
 182
 183         return -1;
 184 }
 185
 186 /**
 187  * Tries to read DWARF info from the location given by path, and
 188  * attach it to the given bin_info instance if it exists.
 189  *
 190  * @param bin   bin_info instance for which to set DWARF info
 191  * @param path  Presumed location of the DWARF info
 192  * @returns     0 on success, negative value on failure
 193  */
 194 static
 195 int bin_info_set_dwarf_info_from_path(struct bin_info *bin, char *path)
 196 {
 197         int fd = -1, ret = 0;
 198         struct bt_dwarf_cu *cu = NULL;
 199         Dwarf *dwarf_info = NULL;
 200
 201         if (!bin || !path) {
 202                 goto error;
 203         }
 204
 205         fd = open(path, O_RDONLY);
 206         if (fd < 0) {
 207                 fd = -errno;
 208                 goto error;
 209         }
 210
 211         dwarf_info = dwarf_begin(fd, DWARF_C_READ);
 212         if (!dwarf_info) {
 213                 goto error;
 214         }
 215
 216         /*
 217          * Check if the dwarf info has any CU. If not, the
 218          * executable's object file contains no DWARF info.
 219          */
 220         cu = bt_dwarf_cu_create(dwarf_info);
 221         if (!cu) {
 222                 goto error;
 223         }
 224
 225         ret = bt_dwarf_cu_next(cu);
 226         if (ret) {
 227                 goto error;
 228         }
 229
 230         bin->dwarf_fd = fd;
 231         bin->dwarf_path = strdup(path);
 232         if (!bin->dwarf_path) {
 233                 goto error;
 234         }
 235         bin->dwarf_info = dwarf_info;
 236         free(cu);
 237
 238         return 0;
 239
 240 error:
 241         if (fd >= 0) {
 242                 close(fd);
 243                 fd = -1;
 244         }
 245         dwarf_end(dwarf_info);
 246         g_free(dwarf_info);
 247         free(cu);
 248
 249         return fd;
 250 }
 251
 252 /**
 253  * Try to set the dwarf_info for a given bin_info instance via the
 254  * build ID method.
 255  *
 256  * @param bin           bin_info instance for which to retrieve the
 257  *                      DWARF info via build ID
 258  * @returns             0 on success (i.e. dwarf_info set), -1 on failure
 259  */
 260 static
 261 int bin_info_set_dwarf_info_build_id(struct bin_info *bin)
 262 {
 263         int i = 0, ret = 0;
 264         char *path = NULL, *build_id_file = NULL;
 265         const char *dbg_dir = NULL;
 266         size_t build_id_file_len;
 267
 268         if (!bin || !bin->build_id) {
 269                 goto error;
 270         }
 271
 272         dbg_dir = opt_debug_info_dir ? : DEFAULT_DEBUG_DIR;
 273
 274         /* 2 characters per byte printed in hex, +1 for '/' and +1 for '\0' */
 275         build_id_file_len = (2 * bin->build_id_len) + 1 +
 276                         strlen(BUILD_ID_SUFFIX) + 1;
 277         build_id_file = malloc(build_id_file_len);
 278         if (!build_id_file) {
 279                 goto error;
 280         }
 281
 282         snprintf(build_id_file, 4, "%02x/", bin->build_id[0]);
 283         for (i = 1; i < bin->build_id_len; ++i) {
 284                 int path_idx = 3 + 2 * (i - 1);
 285
 286                 snprintf(&build_id_file[path_idx], 3, "%02x", bin->build_id[i]);
 287         }
 288         strcat(build_id_file, BUILD_ID_SUFFIX);
 289
 290         path = g_build_path("/", dbg_dir, BUILD_ID_SUBDIR, build_id_file, NULL);
 291         if (!path) {
 292                 goto error;
 293         }
 294
 295         ret = bin_info_set_dwarf_info_from_path(bin, path);
 296         if (ret) {
 297                 goto error;
 298         }
 299
 300         goto end;
 301
 302 error:
 303         ret = -1;
 304 end:
 305         free(build_id_file);
 306         free(path);
 307
 308         return ret;
 309 }
 310
 311 /**
 312  * Tests whether the file located at path exists and has the expected
 313  * checksum.
 314  *
 315  * This predicate is used when looking up separate debug info via the
 316  * GNU debuglink method. The expected crc can be found .gnu_debuglink
 317  * section in the original ELF file, along with the filename for the
 318  * file containing the debug info.
 319  *
 320  * @param path  Full path at which to look for the debug file
 321  * @param crc   Expected checksum for the debug file
 322  * @returns     1 if the file exists and has the correct checksum,
 323  *              0 otherwise
 324  */
 325 static
 326 int is_valid_debug_file(char *path, uint32_t crc)
 327 {
 328         int ret = 0, fd = -1;
 329         uint32_t _crc = 0;
 330
 331         if (!path) {
 332                 goto end;
 333         }
 334
 335         fd = open(path, O_RDONLY);
 336         if (fd < 0) {
 337                 goto end;
 338         }
 339
 340         ret = crc32(fd, &_crc);
 341         if (ret) {
 342                 ret = 0;
 343                 goto end;
 344         }
 345
 346         ret = (crc == _crc);
 347
 348 end:
 349         close(fd);
 350         return ret;
 351 }
 352
 353 /**
 354  * Try to set the dwarf_info for a given bin_info instance via the
 355  * build ID method.
 356  *
 357  * @param bin           bin_info instance for which to retrieve the
 358  *                      DWARF info via debug link
 359  * @returns             0 on success (i.e. dwarf_info set), -1 on failure
 360  */
 361 static
 362 int bin_info_set_dwarf_info_debug_link(struct bin_info *bin)
 363 {
 364         int ret = 0;
 365         const char *dbg_dir = NULL;
 366         char *dir_name = NULL, *bin_dir = NULL, *path = NULL;
 367         size_t max_path_len = 0;
 368
 369         if (!bin || !bin->dbg_link_filename) {
 370                 goto error;
 371         }
 372
 373         dbg_dir = opt_debug_info_dir ? : DEFAULT_DEBUG_DIR;
 374
 375         dir_name = dirname(bin->elf_path);
 376         if (!dir_name) {
 377                 goto error;
 378         }
 379
 380         /* bin_dir is just dir_name with a trailing slash */
 381         bin_dir = malloc(strlen(dir_name) + 2);
 382         if (!bin_dir) {
 383                 goto error;
 384         }
 385
 386         strcpy(bin_dir, dir_name);
 387         strcat(bin_dir, "/");
 388
 389         max_path_len = strlen(dbg_dir) + strlen(bin_dir) +
 390                         strlen(DEBUG_SUBDIR) + strlen(bin->dbg_link_filename)
 391                         + 1;
 392         path = malloc(max_path_len);
 393         if (!path) {
 394                 goto error;
 395         }
 396
 397         /* First look in the executable's dir */
 398         strcpy(path, bin_dir);
 399         strcat(path, bin->dbg_link_filename);
 400
 401         if (is_valid_debug_file(path, bin->dbg_link_crc)) {
 402                 goto found;
 403         }
 404
 405         /* If not found, look in .debug subdir */
 406         strcpy(path, bin_dir);
 407         strcat(path, DEBUG_SUBDIR);
 408         strcat(path, bin->dbg_link_filename);
 409
 410         if (is_valid_debug_file(path, bin->dbg_link_crc)) {
 411                 goto found;
 412         }
 413
 414         /* Lastly, look under the global debug directory */
 415         strcpy(path, dbg_dir);
 416         strcat(path, bin_dir);
 417         strcat(path, bin->dbg_link_filename);
 418
 419         if (is_valid_debug_file(path, bin->dbg_link_crc)) {
 420                 goto found;
 421         }
 422
 423 error:
 424         ret = -1;
 425 end:
 426         free(path);
 427         free(bin_dir);
 428
 429         return ret;
 430
 431 found:
 432         ret = bin_info_set_dwarf_info_from_path(bin, path);
 433         if (ret) {
 434                 goto error;
 435         }
 436
 437         goto end;
 438 }
 439
 440 /**
 441  * Initialize the DWARF info for a given executable.
 442  *
 443  * @param bin   bin_info instance
 444  * @returns     0 on success, negative value on failure
 445  */
 446 static
 447 int bin_info_set_dwarf_info(struct bin_info *bin)
 448 {
 449         int ret = 0;
 450
 451         if (!bin) {
 452                 ret = -1;
 453                 goto end;
 454         }
 455
 456         /* First try to set the DWARF info from the ELF file */
 457         ret = bin_info_set_dwarf_info_from_path(bin, bin->elf_path);
 458         if (!ret) {
 459                 goto end;
 460         }
 461
 462         /*
 463          * If that fails, try to find separate debug info via build ID
 464          * and debug link.
 465          */
 466         ret = bin_info_set_dwarf_info_build_id(bin);
 467         if (!ret) {
 468                 goto end;
 469         }
 470
 471         ret = bin_info_set_dwarf_info_debug_link(bin);
 472         if (!ret) {
 473                 goto end;
 474         }
 475
 476 end:
 477         return ret;
 478 }
 479
 480 /**
 481  * Initialize the ELF file for a given executable.
 482  *
 483  * @param bin   bin_info instance
 484  * @returns     0 on success, negative value on error.
 485  */
 486 static
 487 int bin_info_set_elf_file(struct bin_info *bin)
 488 {
 489         int elf_fd = -1;
 490         Elf *elf_file = NULL;
 491
 492         if (!bin) {
 493                 goto error;
 494         }
 495
 496         elf_fd = open(bin->elf_path, O_RDONLY);
 497         if (elf_fd < 0) {
 498                 elf_fd = -errno;
 499                 printf_verbose("Failed to open %s\n", bin->elf_path);
 500                 goto error;
 501         }
 502
 503         elf_file = elf_begin(elf_fd, ELF_C_READ, NULL);
 504         if (!elf_file) {
 505                 printf_debug("elf_begin failed: %s\n", elf_errmsg(-1));
 506                 goto error;
 507         }
 508
 509         if (elf_kind(elf_file) != ELF_K_ELF) {
 510                 printf_verbose("Error: %s is not an ELF object\n",
 511                                 bin->elf_path);
 512                 goto error;
 513         }
 514
 515         bin->elf_fd = elf_fd;
 516         bin->elf_file = elf_file;
 517         return 0;
 518
 519 error:
 520         if (elf_fd >= 0) {
 521                 close(elf_fd);
 522                 elf_fd = -1;
 523         }
 524         elf_end(elf_file);
 525         return elf_fd;
 526 }
 527
 528 BT_HIDDEN
 529 void source_location_destroy(struct source_location *src_loc)
 530 {
 531         if (!src_loc) {
 532                 return;
 533         }
 534
 535         free(src_loc->filename);
 536         g_free(src_loc);
 537 }
 538
 539 /**
 540  * Append a string representation of an address offset to an existing
 541  * string.
 542  *
 543  * On success, the out parameter `result` will contain the base string
 544  * followed by the offset string of the form "+0x1234". On failure,
 545  * `result` remains unchanged.
 546  *
 547  * @param base_str      The string to which to append an offset string
 548  * @param low_addr      The lower virtual memory address, the base from
 549  *                      which the offset is computed
 550  * @param high_addr     The higher virtual memory address
 551  * @param result        Out parameter, the base string followed by the
 552  *                      offset string
 553  * @returns             0 on success, -1 on failure
 554  */
 555 static
 556 int bin_info_append_offset_str(const char *base_str, uint64_t low_addr,
 557                                 uint64_t high_addr, char **result)
 558 {
 559         int ret;
 560         uint64_t offset;
 561         char *_result = NULL;
 562         char offset_str[ADDR_STR_LEN];
 563
 564         if (!base_str || !result) {
 565                 goto error;
 566         }
 567
 568         offset = high_addr - low_addr;
 569
 570         _result = malloc(strlen(base_str) + ADDR_STR_LEN);
 571         if (!_result) {
 572                 goto error;
 573         }
 574
 575         ret = snprintf(offset_str, ADDR_STR_LEN, "+%#0" PRIx64, offset);
 576         if (ret < 0) {
 577                 goto error;
 578         }
 579         strcpy(_result, base_str);
 580         strcat(_result, offset_str);
 581         *result = _result;
 582
 583         return 0;
 584
 585 error:
 586         free(_result);
 587         return -1;
 588 }
 589
 590 /**
 591  * Try to find the symbol closest to an address within a given ELF
 592  * section.
 593  *
 594  * Only function symbols are taken into account. The symbol's address
 595  * must precede `addr`. A symbol with a closer address might exist
 596  * after `addr` but is irrelevant because it cannot encompass `addr`.
 597  *
 598  * On success, if found, the out parameters `sym` and `shdr` are
 599  * set. On failure or if none are found, they remain unchanged.
 600  *
 601  * @param scn           ELF section in which to look for the address
 602  * @param addr          Virtual memory address for which to find the
 603  *                      nearest function symbol
 604  * @param sym           Out parameter, the nearest function symbol
 605  * @param shdr          Out parameter, the section header for scn
 606  * @returns             0 on success, -1 on failure
 607  */
 608 static
 609 int bin_info_get_nearest_symbol_from_section(Elf_Scn *scn, uint64_t addr,
 610                 GElf_Sym **sym, GElf_Shdr **shdr)
 611 {
 612         int i;
 613         size_t symbol_count;
 614         Elf_Data *data = NULL;
 615         GElf_Shdr *_shdr = NULL;
 616         GElf_Sym *nearest_sym = NULL;
 617
 618         if (!scn || !sym || !shdr) {
 619                 goto error;
 620         }
 621
 622         _shdr = g_new0(GElf_Shdr, 1);
 623         if (!_shdr) {
 624                 goto error;
 625         }
 626
 627         _shdr = gelf_getshdr(scn, _shdr);
 628         if (!_shdr) {
 629                 goto error;
 630         }
 631
 632         if (_shdr->sh_type != SHT_SYMTAB) {
 633                 /*
 634                  * We are only interested in symbol table (symtab)
 635                  * sections, skip this one.
 636                  */
 637                 goto end;
 638         }
 639
 640         data = elf_getdata(scn, NULL);
 641         if (!data) {
 642                 goto error;
 643         }
 644
 645         symbol_count = _shdr->sh_size / _shdr->sh_entsize;
 646
 647         for (i = 0; i < symbol_count; ++i) {
 648                 GElf_Sym *cur_sym = NULL;
 649
 650                 cur_sym = g_new0(GElf_Sym, 1);
 651                 if (!cur_sym) {
 652                         goto error;
 653                 }
 654                 cur_sym = gelf_getsym(data, i, cur_sym);
 655                 if (!cur_sym) {
 656                         goto error;
 657                 }
 658                 if (GELF_ST_TYPE(cur_sym->st_info) != STT_FUNC) {
 659                         /* We're only interested in the functions. */
 660                         g_free(cur_sym);
 661                         continue;
 662                 }
 663
 664                 if (cur_sym->st_value <= addr &&
 665                                 (!nearest_sym ||
 666                                 cur_sym->st_value > nearest_sym->st_value)) {
 667                         g_free(nearest_sym);
 668                         nearest_sym = cur_sym;
 669                 } else {
 670                         g_free(cur_sym);
 671                 }
 672         }
 673
 674 end:
 675         if (nearest_sym) {
 676                 *sym = nearest_sym;
 677                 *shdr = _shdr;
 678         } else {
 679                 g_free(_shdr);
 680         }
 681
 682         return 0;
 683
 684 error:
 685         g_free(nearest_sym);
 686         g_free(_shdr);
 687         return -1;
 688 }
 689
 690 /**
 691  * Get the name of the function containing a given address within an
 692  * executable using ELF symbols.
 693  *
 694  * The function name is in fact the name of the nearest ELF symbol,
 695  * followed by the offset in bytes between the address and the symbol
 696  * (in hex), separated by a '+' character.
 697  *
 698  * If found, the out parameter `func_name` is set on success. On failure,
 699  * it remains unchanged.
 700  *
 701  * @param bin           bin_info instance for the executable containing
 702  *                      the address
 703  * @param addr          Virtual memory address for which to find the
 704  *                      function name
 705  * @param func_name     Out parameter, the function name
 706  * @returns             0 on success, -1 on failure
 707  */
 708 static
 709 int bin_info_lookup_elf_function_name(struct bin_info *bin, uint64_t addr,
 710                 char **func_name)
 711 {
 712         /*
 713          * TODO (possible optimisation): if an ELF has no symtab
 714          * section, it has been stripped. Therefore, it would be wise
 715          * to store a flag indicating the stripped status after the
 716          * first iteration to prevent subsequent ones.
 717          */
 718         int ret = 0;
 719         Elf_Scn *scn = NULL;
 720         GElf_Sym *sym = NULL;
 721         GElf_Shdr *shdr = NULL;
 722         char *sym_name = NULL;
 723
 724         /* Set ELF file if it hasn't been accessed yet. */
 725         if (!bin->elf_file) {
 726                 ret = bin_info_set_elf_file(bin);
 727                 if (ret) {
 728                         /* Failed to set ELF file. */
 729                         goto error;
 730                 }
 731         }
 732
 733         scn = elf_nextscn(bin->elf_file, scn);
 734         if (!scn) {
 735                 goto error;
 736         }
 737
 738         while (scn && !sym) {
 739                 ret = bin_info_get_nearest_symbol_from_section(
 740                                 scn, addr, &sym, &shdr);
 741                 if (ret) {
 742                         goto error;
 743                 }
 744
 745                 scn = elf_nextscn(bin->elf_file, scn);
 746         }
 747
 748         if (sym) {
 749                 sym_name = elf_strptr(bin->elf_file, shdr->sh_link,
 750                                 sym->st_name);
 751                 if (!sym_name) {
 752                         goto error;
 753                 }
 754
 755                 ret = bin_info_append_offset_str(sym_name, sym->st_value, addr,
 756                                                 func_name);
 757                 if (ret) {
 758                         goto error;
 759                 }
 760         }
 761
 762         g_free(shdr);
 763         g_free(sym);
 764         return 0;
 765
 766 error:
 767         g_free(shdr);
 768         g_free(sym);
 769         return ret;
 770 }
 771
 772 /**
 773  * Get the name of the function containing a given address within a
 774  * given compile unit (CU).
 775  *
 776  * If found, the out parameter `func_name` is set on success. On
 777  * failure, it remains unchanged.
 778  *
 779  * @param cu            bt_dwarf_cu instance which may contain the address
 780  * @param addr          Virtual memory address for which to find the
 781  *                      function name
 782  * @param func_name     Out parameter, the function name
 783  * @returns             0 on success, -1 on failure
 784  */
 785 static
 786 int bin_info_lookup_cu_function_name(struct bt_dwarf_cu *cu, uint64_t addr,
 787                 char **func_name)
 788 {
 789         int ret = 0;
 790         bool found = false;
 791         struct bt_dwarf_die *die = NULL;
 792
 793         if (!cu || !func_name) {
 794                 goto error;
 795         }
 796
 797         die = bt_dwarf_die_create(cu);
 798         if (!die) {
 799                 goto error;
 800         }
 801
 802         while (bt_dwarf_die_next(die) == 0) {
 803                 int tag;
 804
 805                 ret = bt_dwarf_die_get_tag(die, &tag);
 806                 if (ret) {
 807                         goto error;
 808                 }
 809
 810                 if (tag == DW_TAG_subprogram) {
 811                         ret = bt_dwarf_die_contains_addr(die, addr, &found);
 812                         if (ret) {
 813                                 goto error;
 814                         }
 815
 816                         if (found) {
 817                                 break;
 818                         }
 819                 }
 820         }
 821
 822         if (found) {
 823                 uint64_t low_addr = 0;
 824                 char *die_name = NULL;
 825
 826                 ret = bt_dwarf_die_get_name(die, &die_name);
 827                 if (ret) {
 828                         goto error;
 829                 }
 830
 831                 ret = dwarf_lowpc(die->dwarf_die, &low_addr);
 832                 if (ret) {
 833                         free(die_name);
 834                         goto error;
 835                 }
 836
 837                 ret = bin_info_append_offset_str(die_name, low_addr, addr,
 838                                                 func_name);
 839                 free(die_name);
 840                 if (ret) {
 841                         goto error;
 842                 }
 843         }
 844
 845         bt_dwarf_die_destroy(die);
 846         return 0;
 847
 848 error:
 849         bt_dwarf_die_destroy(die);
 850         return -1;
 851 }
 852
 853 /**
 854  * Get the name of the function containing a given address within an
 855  * executable using DWARF debug info.
 856  *
 857  * If found, the out parameter `func_name` is set on success. On
 858  * failure, it remains unchanged.
 859  *
 860  * @param bin           bin_info instance for the executable containing
 861  *                      the address
 862  * @param addr          Virtual memory address for which to find the
 863  *                      function name
 864  * @param func_name     Out parameter, the function name
 865  * @returns             0 on success, -1 on failure
 866  */
 867 static
 868 int bin_info_lookup_dwarf_function_name(struct bin_info *bin, uint64_t addr,
 869                 char **func_name)
 870 {
 871         int ret = 0;
 872         char *_func_name = NULL;
 873         struct bt_dwarf_cu *cu = NULL;
 874
 875         if (!bin || !func_name) {
 876                 goto error;
 877         }
 878
 879         cu = bt_dwarf_cu_create(bin->dwarf_info);
 880         if (!cu) {
 881                 goto error;
 882         }
 883
 884         while (bt_dwarf_cu_next(cu) == 0) {
 885                 ret = bin_info_lookup_cu_function_name(cu, addr, &_func_name);
 886                 if (ret) {
 887                         goto error;
 888                 }
 889
 890                 if (_func_name) {
 891                         break;
 892                 }
 893         }
 894
 895         if (_func_name) {
 896                 *func_name = _func_name;
 897         } else {
 898                 goto error;
 899         }
 900
 901         bt_dwarf_cu_destroy(cu);
 902         return 0;
 903
 904 error:
 905         bt_dwarf_cu_destroy(cu);
 906         return -1;
 907 }
 908
 909 BT_HIDDEN
 910 int bin_info_lookup_function_name(struct bin_info *bin, uint64_t addr,
 911                 char **func_name)
 912 {
 913         int ret = 0;
 914         char *_func_name = NULL;
 915
 916         if (!bin || !func_name) {
 917                 goto error;
 918         }
 919
 920         /* Set DWARF info if it hasn't been accessed yet. */
 921         if (!bin->dwarf_info && !bin->is_elf_only) {
 922                 ret = bin_info_set_dwarf_info(bin);
 923                 if (ret) {
 924                         printf_verbose("Failed to set bin dwarf info, falling back to ELF lookup.\n");
 925                         /* Failed to set DWARF info, fallback to ELF. */
 926                         bin->is_elf_only = true;
 927                 }
 928         }
 929
 930         if (!bin_info_has_address(bin, addr)) {
 931                 goto error;
 932         }
 933
 934         /*
 935          * Addresses in ELF and DWARF are relative to base address for
 936          * PIC, so make the address argument relative too if needed.
 937          */
 938         if (bin->is_pic) {
 939                 addr -= bin->low_addr;
 940         }
 941
 942         if (bin->is_elf_only) {
 943                 ret = bin_info_lookup_elf_function_name(bin, addr, &_func_name);
 944                 printf_verbose("Failed to lookup function name (elf), error %i\n", ret);
 945         } else {
 946                 ret = bin_info_lookup_dwarf_function_name(bin, addr, &_func_name);
 947                 printf_verbose("Failed to lookup function name (dwarf), error %i\n", ret);
 948         }
 949
 950         *func_name = _func_name;
 951         return 0;
 952
 953 error:
 954         return -1;
 955 }
 956
 957 BT_HIDDEN
 958 int bin_info_get_bin_loc(struct bin_info *bin, uint64_t addr, char **bin_loc)
 959 {
 960         int ret = 0;
 961         char *_bin_loc = NULL;
 962
 963         if (!bin || !bin_loc) {
 964                 goto error;
 965         }
 966
 967         if (bin->is_pic) {
 968                 addr -= bin->low_addr;
 969                 ret = asprintf(&_bin_loc, "+%#0" PRIx64, addr);
 970         } else {
 971                 ret = asprintf(&_bin_loc, "@%#0" PRIx64, addr);
 972         }
 973
 974         if (ret == -1 || !_bin_loc) {
 975                 goto error;
 976         }
 977
 978         *bin_loc = _bin_loc;
 979         return 0;
 980
 981 error:
 982         return -1;
 983 }
 984
 985 /**
 986  * Predicate used to determine whether the children of a given DIE
 987  * contain a specific address.
 988  *
 989  * More specifically, the parameter `die` is expected to be a
 990  * subprogram (function) DIE, and this predicate tells whether any
 991  * subroutines are inlined within this function and would contain
 992  * `addr`.
 993  *
 994  * On success, the out parameter `contains` is set with the boolean
 995  * value indicating whether the DIE's range covers `addr`. On failure,
 996  * it remains unchanged.
 997  *
 998  * Do note that this function advances the position of `die`. If the
 999  * address is found within one of its children, `die` will be pointing
1000  * to that child upon returning from the function, allowing to extract
1001  * the information deemed necessary.
1002  *
1003  * @param die           The parent DIE in whose children the address will be
1004  *                      looked for
1005  * @param addr          The address for which to look for in the DIEs
1006  * @param contains      Out parameter, true if addr is contained,
1007  *                      false if not
1008  * @returns             Returns 0 on success, -1 on failure
1009  */
1010 static
1011 int bin_info_child_die_has_address(struct bt_dwarf_die *die, uint64_t addr, bool *contains)
1012 {
1013         int ret = 0;
1014         bool _contains = false;
1015
1016         if (!die) {
1017                 goto error;
1018         }
1019
1020         ret = bt_dwarf_die_child(die);
1021         if (ret) {
1022                 goto error;
1023         }
1024
1025         do {
1026                 int tag;
1027
1028                 ret = bt_dwarf_die_get_tag(die, &tag);
1029                 if (ret) {
1030                         goto error;
1031                 }
1032
1033                 if (tag == DW_TAG_inlined_subroutine) {
1034                         ret = bt_dwarf_die_contains_addr(die, addr, &_contains);
1035                         if (ret) {
1036                                 goto error;
1037                         }
1038
1039                         if (contains) {
1040                                 goto end;
1041                         }
1042                 }
1043         } while (bt_dwarf_die_next(die) == 0);
1044
1045 end:
1046         *contains = _contains;
1047         return 0;
1048
1049 error:
1050         return -1;
1051 }
1052
1053 /**
1054  * Lookup the source location for a given address within a CU, making
1055  * the assumption that it is contained within an inline routine in a
1056  * function.
1057  *
1058  * @param cu            bt_dwarf_cu instance in which to look for the address
1059  * @param addr          The address for which to look for
1060  * @param src_loc       Out parameter, the source location (filename and
1061  *                      line number) for the address
1062  * @returns             0 on success, -1 on failure
1063  */
1064 static
1065 int bin_info_lookup_cu_src_loc_inl(struct bt_dwarf_cu *cu, uint64_t addr,
1066                 struct source_location **src_loc)
1067 {
1068         int ret = 0;
1069         bool found = false;
1070         struct bt_dwarf_die *die = NULL;
1071         struct source_location *_src_loc = NULL;
1072
1073         if (!cu || !src_loc) {
1074                 goto error;
1075         }
1076
1077         die = bt_dwarf_die_create(cu);
1078         if (!die) {
1079                 goto error;
1080         }
1081
1082         while (bt_dwarf_die_next(die) == 0) {
1083                 int tag;
1084
1085                 ret = bt_dwarf_die_get_tag(die, &tag);
1086                 if (ret) {
1087                         goto error;
1088                 }
1089
1090                 if (tag == DW_TAG_subprogram) {
1091                         bool contains = false;
1092
1093                         ret = bt_dwarf_die_contains_addr(die, addr, &contains);
1094                         if (ret) {
1095                                 goto error;
1096                         }
1097
1098                         if (contains) {
1099                                 /*
1100                                  * Try to find an inlined subroutine
1101                                  * child of this DIE containing addr.
1102                                  */
1103                                 ret = bin_info_child_die_has_address(die, addr,
1104                                                 &found);
1105                                 if(ret) {
1106                                         goto error;
1107                                 }
1108
1109                                 goto end;
1110                         }
1111                 }
1112         }
1113
1114 end:
1115         if (found) {
1116                 char *filename = NULL;
1117                 uint64_t line_no;
1118
1119                 _src_loc = g_new0(struct source_location, 1);
1120                 if (!_src_loc) {
1121                         goto error;
1122                 }
1123
1124                 ret = bt_dwarf_die_get_call_file(die, &filename);
1125                 if (ret) {
1126                         goto error;
1127                 }
1128                 ret = bt_dwarf_die_get_call_line(die, &line_no);
1129                 if (ret) {
1130                         free(filename);
1131                         goto error;
1132                 }
1133
1134                 _src_loc->filename = filename;
1135                 _src_loc->line_no = line_no;
1136                 *src_loc = _src_loc;
1137         }
1138
1139         bt_dwarf_die_destroy(die);
1140         return 0;
1141
1142 error:
1143         source_location_destroy(_src_loc);
1144         bt_dwarf_die_destroy(die);
1145         return -1;
1146 }
1147
1148 /**
1149  * Lookup the source location for a given address within a CU,
1150  * assuming that it is contained within an inlined function.
1151  *
1152  * A source location can be found regardless of inlining status for
1153  * this method, but in the case of an inlined function, the returned
1154  * source location will point not to the callsite but rather to the
1155  * definition site of the inline function.
1156  *
1157  * @param cu            bt_dwarf_cu instance in which to look for the address
1158  * @param addr          The address for which to look for
1159  * @param src_loc       Out parameter, the source location (filename and
1160  *                      line number) for the address
1161  * @returns             0 on success, -1 on failure
1162  */
1163 static
1164 int bin_info_lookup_cu_src_loc_no_inl(struct bt_dwarf_cu *cu, uint64_t addr,
1165                 struct source_location **src_loc)
1166 {
1167         struct source_location *_src_loc = NULL;
1168         struct bt_dwarf_die *die = NULL;
1169         const char *filename = NULL;
1170         Dwarf_Line *line = NULL;
1171         Dwarf_Addr line_addr;
1172         int ret, line_no;
1173
1174         if (!cu || !src_loc) {
1175                 goto error;
1176         }
1177
1178         die = bt_dwarf_die_create(cu);
1179         if (!die) {
1180                 goto error;
1181         }
1182
1183         line = dwarf_getsrc_die(die->dwarf_die, addr);
1184         if (!line) {
1185                 goto error;
1186         }
1187
1188         ret = dwarf_lineaddr(line, &line_addr);
1189         if (ret) {
1190                 goto error;
1191         }
1192
1193         filename = dwarf_linesrc(line, NULL, NULL);
1194         if (!filename) {
1195                 goto error;
1196         }
1197
1198         if (addr == line_addr) {
1199                 _src_loc = g_new0(struct source_location, 1);
1200                 if (!_src_loc) {
1201                         goto error;
1202                 }
1203
1204                 ret = dwarf_lineno(line, &line_no);
1205                 if (ret) {
1206                         goto error;
1207                 }
1208
1209                 _src_loc->line_no = line_no;
1210                 _src_loc->filename = strdup(filename);
1211         }
1212
1213         bt_dwarf_die_destroy(die);
1214
1215         if (_src_loc) {
1216                 *src_loc = _src_loc;
1217         }
1218
1219         return 0;
1220
1221 error:
1222         source_location_destroy(_src_loc);
1223         bt_dwarf_die_destroy(die);
1224         return -1;
1225 }
1226
1227 /**
1228  * Get the source location (file name and line number) for a given
1229  * address within a compile unit (CU).
1230  *
1231  * On success, the out parameter `src_loc` is set if found. On
1232  * failure, it remains unchanged.
1233  *
1234  * @param cu            bt_dwarf_cu instance for the compile unit which
1235  *                      may contain the address
1236  * @param addr          Virtual memory address for which to find the
1237  *                      source location
1238  * @param src_loc       Out parameter, the source location
1239  * @returns             0 on success, -1 on failure
1240  */
1241 static
1242 int bin_info_lookup_cu_src_loc(struct bt_dwarf_cu *cu, uint64_t addr,
1243                 struct source_location **src_loc)
1244 {
1245         int ret = 0;
1246         struct source_location *_src_loc = NULL;
1247
1248         if (!cu || !src_loc) {
1249                 goto error;
1250         }
1251
1252         ret = bin_info_lookup_cu_src_loc_inl(cu, addr, &_src_loc);
1253         if (ret) {
1254                 goto error;
1255         }
1256
1257         if (_src_loc) {
1258                 goto end;
1259         }
1260
1261         ret = bin_info_lookup_cu_src_loc_no_inl(cu, addr, &_src_loc);
1262         if (ret) {
1263                 goto error;
1264         }
1265
1266         if (_src_loc) {
1267                 goto end;
1268         }
1269
1270 end:
1271         if (_src_loc) {
1272                 *src_loc = _src_loc;
1273         }
1274
1275         return 0;
1276
1277 error:
1278         source_location_destroy(_src_loc);
1279         return -1;
1280 }
1281
1282 BT_HIDDEN
1283 int bin_info_lookup_source_location(struct bin_info *bin, uint64_t addr,
1284                 struct source_location **src_loc)
1285 {
1286         struct bt_dwarf_cu *cu = NULL;
1287         struct source_location *_src_loc = NULL;
1288
1289         if (!bin || !src_loc) {
1290                 goto error;
1291         }
1292
1293         /* Set DWARF info if it hasn't been accessed yet. */
1294         if (!bin->dwarf_info && !bin->is_elf_only) {
1295                 if (bin_info_set_dwarf_info(bin)) {
1296                         /* Failed to set DWARF info. */
1297                         bin->is_elf_only = true;
1298                 }
1299         }
1300
1301         if (bin->is_elf_only) {
1302                 /* We cannot lookup source location without DWARF info. */
1303                 goto error;
1304         }
1305
1306         if (!bin_info_has_address(bin, addr)) {
1307                 goto error;
1308         }
1309
1310         /*
1311          * Addresses in ELF and DWARF are relative to base address for
1312          * PIC, so make the address argument relative too if needed.
1313          */
1314         if (bin->is_pic) {
1315                 addr -= bin->low_addr;
1316         }
1317
1318         cu = bt_dwarf_cu_create(bin->dwarf_info);
1319         if (!cu) {
1320                 goto error;
1321         }
1322
1323         while (bt_dwarf_cu_next(cu) == 0) {
1324                 int ret;
1325
1326                 ret = bin_info_lookup_cu_src_loc(cu, addr, &_src_loc);
1327                 if (ret) {
1328                         goto error;
1329                 }
1330
1331                 if (_src_loc) {
1332                         break;
1333                 }
1334         }
1335
1336         bt_dwarf_cu_destroy(cu);
1337         if (_src_loc) {
1338                 *src_loc = _src_loc;
1339         }
1340
1341         return 0;
1342
1343 error:
1344         source_location_destroy(_src_loc);
1345         bt_dwarf_cu_destroy(cu);
1346         return -1;
1347 }