plugins/debug-info/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 <errno.h>
  40 #include <babeltrace/babeltrace-internal.h>
  41 #include "dwarf.h"
  42 #include "bin-info.h"
  43 #include "crc32.h"
  44 #include "utils.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         g_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, const char *filename,
 160                 uint32_t crc)
 161 {
 162         if (!bin || !filename) {
 163                 goto error;
 164         }
 165
 166         bin->dbg_link_filename = strdup(filename);
 167         if (!bin->dbg_link_filename) {
 168                 goto error;
 169         }
 170
 171         bin->dbg_link_crc = crc;
 172
 173         /*
 174          * Reset the is_elf_only flag in case it had been set
 175          * previously, because we might find separate debug info using
 176          * the new build id information.
 177          */
 178         bin->is_elf_only = false;
 179
 180         return 0;
 181
 182 error:
 183
 184         return -1;
 185 }
 186
 187 /**
 188  * Tries to read DWARF info from the location given by path, and
 189  * attach it to the given bin_info instance if it exists.
 190  *
 191  * @param bin   bin_info instance for which to set DWARF info
 192  * @param path  Presumed location of the DWARF info
 193  * @returns     0 on success, negative value on failure
 194  */
 195 static
 196 int bin_info_set_dwarf_info_from_path(struct bin_info *bin, char *path)
 197 {
 198         int fd = -1, ret = 0;
 199         struct bt_dwarf_cu *cu = NULL;
 200         Dwarf *dwarf_info = NULL;
 201
 202         if (!bin || !path) {
 203                 goto error;
 204         }
 205
 206         fd = open(path, O_RDONLY);
 207         if (fd < 0) {
 208                 fd = -errno;
 209                 goto error;
 210         }
 211
 212         dwarf_info = dwarf_begin(fd, DWARF_C_READ);
 213         if (!dwarf_info) {
 214                 goto error;
 215         }
 216
 217         /*
 218          * Check if the dwarf info has any CU. If not, the
 219          * executable's object file contains no DWARF info.
 220          */
 221         cu = bt_dwarf_cu_create(dwarf_info);
 222         if (!cu) {
 223                 goto error;
 224         }
 225
 226         ret = bt_dwarf_cu_next(cu);
 227         if (ret) {
 228                 goto error;
 229         }
 230
 231         bin->dwarf_fd = fd;
 232         bin->dwarf_path = strdup(path);
 233         if (!bin->dwarf_path) {
 234                 goto error;
 235         }
 236         bin->dwarf_info = dwarf_info;
 237         free(cu);
 238
 239         return 0;
 240
 241 error:
 242         if (fd >= 0) {
 243                 close(fd);
 244                 fd = -1;
 245         }
 246         dwarf_end(dwarf_info);
 247         g_free(dwarf_info);
 248         free(cu);
 249
 250         return fd;
 251 }
 252
 253 /**
 254  * Try to set the dwarf_info for a given bin_info instance via the
 255  * build ID method.
 256  *
 257  * @param bin           bin_info instance for which to retrieve the
 258  *                      DWARF info via build ID
 259  * @returns             0 on success (i.e. dwarf_info set), -1 on failure
 260  */
 261 static
 262 int bin_info_set_dwarf_info_build_id(struct bin_info *bin)
 263 {
 264         int i = 0, ret = 0;
 265         char *path = NULL, *build_id_file = NULL;
 266         const char *dbg_dir = NULL;
 267         size_t build_id_file_len;
 268
 269         if (!bin || !bin->build_id) {
 270                 goto error;
 271         }
 272
 273         dbg_dir = opt_debug_info_dir ? : DEFAULT_DEBUG_DIR;
 274
 275         /* 2 characters per byte printed in hex, +1 for '/' and +1 for '\0' */
 276         build_id_file_len = (2 * bin->build_id_len) + 1 +
 277                         strlen(BUILD_ID_SUFFIX) + 1;
 278         build_id_file = malloc(build_id_file_len);
 279         if (!build_id_file) {
 280                 goto error;
 281         }
 282
 283         snprintf(build_id_file, 4, "%02x/", bin->build_id[0]);
 284         for (i = 1; i < bin->build_id_len; ++i) {
 285                 int path_idx = 3 + 2 * (i - 1);
 286
 287                 snprintf(&build_id_file[path_idx], 3, "%02x", bin->build_id[i]);
 288         }
 289         strcat(build_id_file, BUILD_ID_SUFFIX);
 290
 291         path = g_build_path("/", dbg_dir, BUILD_ID_SUBDIR, build_id_file, NULL);
 292         if (!path) {
 293                 goto error;
 294         }
 295
 296         ret = bin_info_set_dwarf_info_from_path(bin, path);
 297         if (ret) {
 298                 goto error;
 299         }
 300
 301         goto end;
 302
 303 error:
 304         ret = -1;
 305 end:
 306         free(build_id_file);
 307         free(path);
 308
 309         return ret;
 310 }
 311
 312 /**
 313  * Tests whether the file located at path exists and has the expected
 314  * checksum.
 315  *
 316  * This predicate is used when looking up separate debug info via the
 317  * GNU debuglink method. The expected crc can be found .gnu_debuglink
 318  * section in the original ELF file, along with the filename for the
 319  * file containing the debug info.
 320  *
 321  * @param path  Full path at which to look for the debug file
 322  * @param crc   Expected checksum for the debug file
 323  * @returns     1 if the file exists and has the correct checksum,
 324  *              0 otherwise
 325  */
 326 static
 327 int is_valid_debug_file(char *path, uint32_t crc)
 328 {
 329         int ret = 0, fd = -1;
 330         uint32_t _crc = 0;
 331
 332         if (!path) {
 333                 goto end_noclose;
 334         }
 335
 336         fd = open(path, O_RDONLY);
 337         if (fd < 0) {
 338                 goto end_noclose;
 339         }
 340
 341         ret = crc32(fd, &_crc);
 342         if (ret) {
 343                 ret = 0;
 344                 goto end;
 345         }
 346
 347         ret = (crc == _crc);
 348
 349 end:
 350         close(fd);
 351 end_noclose:
 352         return ret;
 353 }
 354
 355 /**
 356  * Try to set the dwarf_info for a given bin_info instance via the
 357  * build ID method.
 358  *
 359  * @param bin           bin_info instance for which to retrieve the
 360  *                      DWARF info via debug link
 361  * @returns             0 on success (i.e. dwarf_info set), -1 on failure
 362  */
 363 static
 364 int bin_info_set_dwarf_info_debug_link(struct bin_info *bin)
 365 {
 366         int ret = 0;
 367         const char *dbg_dir = NULL;
 368         char *dir_name = NULL, *bin_dir = NULL, *path = NULL;
 369         size_t max_path_len = 0;
 370
 371         if (!bin || !bin->dbg_link_filename) {
 372                 goto error;
 373         }
 374
 375         dbg_dir = opt_debug_info_dir ? : DEFAULT_DEBUG_DIR;
 376
 377         dir_name = dirname(bin->elf_path);
 378         if (!dir_name) {
 379                 goto error;
 380         }
 381
 382         /* bin_dir is just dir_name with a trailing slash */
 383         bin_dir = malloc(strlen(dir_name) + 2);
 384         if (!bin_dir) {
 385                 goto error;
 386         }
 387
 388         strcpy(bin_dir, dir_name);
 389         strcat(bin_dir, "/");
 390
 391         max_path_len = strlen(dbg_dir) + strlen(bin_dir) +
 392                         strlen(DEBUG_SUBDIR) + strlen(bin->dbg_link_filename)
 393                         + 1;
 394         path = malloc(max_path_len);
 395         if (!path) {
 396                 goto error;
 397         }
 398
 399         /* First look in the executable's dir */
 400         strcpy(path, bin_dir);
 401         strcat(path, bin->dbg_link_filename);
 402
 403         if (is_valid_debug_file(path, bin->dbg_link_crc)) {
 404                 goto found;
 405         }
 406
 407         /* If not found, look in .debug subdir */
 408         strcpy(path, bin_dir);
 409         strcat(path, DEBUG_SUBDIR);
 410         strcat(path, bin->dbg_link_filename);
 411
 412         if (is_valid_debug_file(path, bin->dbg_link_crc)) {
 413                 goto found;
 414         }
 415
 416         /* Lastly, look under the global debug directory */
 417         strcpy(path, dbg_dir);
 418         strcat(path, bin_dir);
 419         strcat(path, bin->dbg_link_filename);
 420
 421         if (is_valid_debug_file(path, bin->dbg_link_crc)) {
 422                 goto found;
 423         }
 424
 425 error:
 426         ret = -1;
 427 end:
 428         free(path);
 429         free(bin_dir);
 430
 431         return ret;
 432
 433 found:
 434         ret = bin_info_set_dwarf_info_from_path(bin, path);
 435         if (ret) {
 436                 goto error;
 437         }
 438
 439         goto end;
 440 }
 441
 442 /**
 443  * Initialize the DWARF info for a given executable.
 444  *
 445  * @param bin   bin_info instance
 446  * @returns     0 on success, negative value on failure
 447  */
 448 static
 449 int bin_info_set_dwarf_info(struct bin_info *bin)
 450 {
 451         int ret = 0;
 452
 453         if (!bin) {
 454                 ret = -1;
 455                 goto end;
 456         }
 457
 458         /* First try to set the DWARF info from the ELF file */
 459         ret = bin_info_set_dwarf_info_from_path(bin, bin->elf_path);
 460         if (!ret) {
 461                 goto end;
 462         }
 463
 464         /*
 465          * If that fails, try to find separate debug info via build ID
 466          * and debug link.
 467          */
 468         ret = bin_info_set_dwarf_info_build_id(bin);
 469         if (!ret) {
 470                 goto end;
 471         }
 472
 473         ret = bin_info_set_dwarf_info_debug_link(bin);
 474         if (!ret) {
 475                 goto end;
 476         }
 477
 478 end:
 479         return ret;
 480 }
 481
 482 /**
 483  * Initialize the ELF file for a given executable.
 484  *
 485  * @param bin   bin_info instance
 486  * @returns     0 on success, negative value on error.
 487  */
 488 static
 489 int bin_info_set_elf_file(struct bin_info *bin)
 490 {
 491         int elf_fd = -1;
 492         Elf *elf_file = NULL;
 493
 494         if (!bin) {
 495                 goto error;
 496         }
 497
 498         elf_fd = open(bin->elf_path, O_RDONLY);
 499         if (elf_fd < 0) {
 500                 elf_fd = -errno;
 501                 printf_verbose("Failed to open %s\n", bin->elf_path);
 502                 goto error;
 503         }
 504
 505         elf_file = elf_begin(elf_fd, ELF_C_READ, NULL);
 506         if (!elf_file) {
 507                 printf_debug("elf_begin failed: %s\n", elf_errmsg(-1));
 508                 goto error;
 509         }
 510
 511         if (elf_kind(elf_file) != ELF_K_ELF) {
 512                 printf_verbose("Error: %s is not an ELF object\n",
 513                                 bin->elf_path);
 514                 goto error;
 515         }
 516
 517         bin->elf_fd = elf_fd;
 518         bin->elf_file = elf_file;
 519         return 0;
 520
 521 error:
 522         if (elf_fd >= 0) {
 523                 close(elf_fd);
 524                 elf_fd = -1;
 525         }
 526         elf_end(elf_file);
 527         return elf_fd;
 528 }
 529
 530 BT_HIDDEN
 531 void source_location_destroy(struct source_location *src_loc)
 532 {
 533         if (!src_loc) {
 534                 return;
 535         }
 536
 537         free(src_loc->filename);
 538         g_free(src_loc);
 539 }
 540
 541 /**
 542  * Append a string representation of an address offset to an existing
 543  * string.
 544  *
 545  * On success, the out parameter `result` will contain the base string
 546  * followed by the offset string of the form "+0x1234". On failure,
 547  * `result` remains unchanged.
 548  *
 549  * @param base_str      The string to which to append an offset string
 550  * @param low_addr      The lower virtual memory address, the base from
 551  *                      which the offset is computed
 552  * @param high_addr     The higher virtual memory address
 553  * @param result        Out parameter, the base string followed by the
 554  *                      offset string
 555  * @returns             0 on success, -1 on failure
 556  */
 557 static
 558 int bin_info_append_offset_str(const char *base_str, uint64_t low_addr,
 559                                 uint64_t high_addr, char **result)
 560 {
 561         int ret;
 562         uint64_t offset;
 563         char *_result = NULL;
 564         char offset_str[ADDR_STR_LEN];
 565
 566         if (!base_str || !result) {
 567                 goto error;
 568         }
 569
 570         offset = high_addr - low_addr;
 571
 572         _result = malloc(strlen(base_str) + ADDR_STR_LEN);
 573         if (!_result) {
 574                 goto error;
 575         }
 576
 577         ret = snprintf(offset_str, ADDR_STR_LEN, "+%#0" PRIx64, offset);
 578         if (ret < 0) {
 579                 goto error;
 580         }
 581         strcpy(_result, base_str);
 582         strcat(_result, offset_str);
 583         *result = _result;
 584
 585         return 0;
 586
 587 error:
 588         free(_result);
 589         return -1;
 590 }
 591
 592 /**
 593  * Try to find the symbol closest to an address within a given ELF
 594  * section.
 595  *
 596  * Only function symbols are taken into account. The symbol's address
 597  * must precede `addr`. A symbol with a closer address might exist
 598  * after `addr` but is irrelevant because it cannot encompass `addr`.
 599  *
 600  * On success, if found, the out parameters `sym` and `shdr` are
 601  * set. On failure or if none are found, they remain unchanged.
 602  *
 603  * @param scn           ELF section in which to look for the address
 604  * @param addr          Virtual memory address for which to find the
 605  *                      nearest function symbol
 606  * @param sym           Out parameter, the nearest function symbol
 607  * @param shdr          Out parameter, the section header for scn
 608  * @returns             0 on success, -1 on failure
 609  */
 610 static
 611 int bin_info_get_nearest_symbol_from_section(Elf_Scn *scn, uint64_t addr,
 612                 GElf_Sym **sym, GElf_Shdr **shdr)
 613 {
 614         int i;
 615         size_t symbol_count;
 616         Elf_Data *data = NULL;
 617         GElf_Shdr *_shdr = NULL;
 618         GElf_Sym *nearest_sym = NULL;
 619
 620         if (!scn || !sym || !shdr) {
 621                 goto error;
 622         }
 623
 624         _shdr = g_new0(GElf_Shdr, 1);
 625         if (!_shdr) {
 626                 goto error;
 627         }
 628
 629         _shdr = gelf_getshdr(scn, _shdr);
 630         if (!_shdr) {
 631                 goto error;
 632         }
 633
 634         if (_shdr->sh_type != SHT_SYMTAB) {
 635                 /*
 636                  * We are only interested in symbol table (symtab)
 637                  * sections, skip this one.
 638                  */
 639                 goto end;
 640         }
 641
 642         data = elf_getdata(scn, NULL);
 643         if (!data) {
 644                 goto error;
 645         }
 646
 647         symbol_count = _shdr->sh_size / _shdr->sh_entsize;
 648
 649         for (i = 0; i < symbol_count; ++i) {
 650                 GElf_Sym *cur_sym = NULL;
 651
 652                 cur_sym = g_new0(GElf_Sym, 1);
 653                 if (!cur_sym) {
 654                         goto error;
 655                 }
 656                 cur_sym = gelf_getsym(data, i, cur_sym);
 657                 if (!cur_sym) {
 658                         goto error;
 659                 }
 660                 if (GELF_ST_TYPE(cur_sym->st_info) != STT_FUNC) {
 661                         /* We're only interested in the functions. */
 662                         g_free(cur_sym);
 663                         continue;
 664                 }
 665
 666                 if (cur_sym->st_value <= addr &&
 667                                 (!nearest_sym ||
 668                                 cur_sym->st_value > nearest_sym->st_value)) {
 669                         g_free(nearest_sym);
 670                         nearest_sym = cur_sym;
 671                 } else {
 672                         g_free(cur_sym);
 673                 }
 674         }
 675
 676 end:
 677         if (nearest_sym) {
 678                 *sym = nearest_sym;
 679                 *shdr = _shdr;
 680         } else {
 681                 g_free(_shdr);
 682         }
 683
 684         return 0;
 685
 686 error:
 687         g_free(nearest_sym);
 688         g_free(_shdr);
 689         return -1;
 690 }
 691
 692 /**
 693  * Get the name of the function containing a given address within an
 694  * executable using ELF symbols.
 695  *
 696  * The function name is in fact the name of the nearest ELF symbol,
 697  * followed by the offset in bytes between the address and the symbol
 698  * (in hex), separated by a '+' character.
 699  *
 700  * If found, the out parameter `func_name` is set on success. On failure,
 701  * it remains unchanged.
 702  *
 703  * @param bin           bin_info instance for the executable containing
 704  *                      the address
 705  * @param addr          Virtual memory address for which to find the
 706  *                      function name
 707  * @param func_name     Out parameter, the function name
 708  * @returns             0 on success, -1 on failure
 709  */
 710 static
 711 int bin_info_lookup_elf_function_name(struct bin_info *bin, uint64_t addr,
 712                 char **func_name)
 713 {
 714         /*
 715          * TODO (possible optimisation): if an ELF has no symtab
 716          * section, it has been stripped. Therefore, it would be wise
 717          * to store a flag indicating the stripped status after the
 718          * first iteration to prevent subsequent ones.
 719          */
 720         int ret = 0;
 721         Elf_Scn *scn = NULL;
 722         GElf_Sym *sym = NULL;
 723         GElf_Shdr *shdr = NULL;
 724         char *sym_name = NULL;
 725
 726         /* Set ELF file if it hasn't been accessed yet. */
 727         if (!bin->elf_file) {
 728                 ret = bin_info_set_elf_file(bin);
 729                 if (ret) {
 730                         /* Failed to set ELF file. */
 731                         goto error;
 732                 }
 733         }
 734
 735         scn = elf_nextscn(bin->elf_file, scn);
 736         if (!scn) {
 737                 goto error;
 738         }
 739
 740         while (scn && !sym) {
 741                 ret = bin_info_get_nearest_symbol_from_section(
 742                                 scn, addr, &sym, &shdr);
 743                 if (ret) {
 744                         goto error;
 745                 }
 746
 747                 scn = elf_nextscn(bin->elf_file, scn);
 748         }
 749
 750         if (sym) {
 751                 sym_name = elf_strptr(bin->elf_file, shdr->sh_link,
 752                                 sym->st_name);
 753                 if (!sym_name) {
 754                         goto error;
 755                 }
 756
 757                 ret = bin_info_append_offset_str(sym_name, sym->st_value, addr,
 758                                                 func_name);
 759                 if (ret) {
 760                         goto error;
 761                 }
 762         }
 763
 764         g_free(shdr);
 765         g_free(sym);
 766         return 0;
 767
 768 error:
 769         g_free(shdr);
 770         g_free(sym);
 771         return ret;
 772 }
 773
 774 /**
 775  * Get the name of the function containing a given address within a
 776  * given compile unit (CU).
 777  *
 778  * If found, the out parameter `func_name` is set on success. On
 779  * failure, it remains unchanged.
 780  *
 781  * @param cu            bt_dwarf_cu instance which may contain the address
 782  * @param addr          Virtual memory address for which to find the
 783  *                      function name
 784  * @param func_name     Out parameter, the function name
 785  * @returns             0 on success, -1 on failure
 786  */
 787 static
 788 int bin_info_lookup_cu_function_name(struct bt_dwarf_cu *cu, uint64_t addr,
 789                 char **func_name)
 790 {
 791         int ret = 0;
 792         bool found = false;
 793         struct bt_dwarf_die *die = NULL;
 794
 795         if (!cu || !func_name) {
 796                 goto error;
 797         }
 798
 799         die = bt_dwarf_die_create(cu);
 800         if (!die) {
 801                 goto error;
 802         }
 803
 804         while (bt_dwarf_die_next(die) == 0) {
 805                 int tag;
 806
 807                 ret = bt_dwarf_die_get_tag(die, &tag);
 808                 if (ret) {
 809                         goto error;
 810                 }
 811
 812                 if (tag == DW_TAG_subprogram) {
 813                         ret = bt_dwarf_die_contains_addr(die, addr, &found);
 814                         if (ret) {
 815                                 goto error;
 816                         }
 817
 818                         if (found) {
 819                                 break;
 820                         }
 821                 }
 822         }
 823
 824         if (found) {
 825                 uint64_t low_addr = 0;
 826                 char *die_name = NULL;
 827
 828                 ret = bt_dwarf_die_get_name(die, &die_name);
 829                 if (ret) {
 830                         goto error;
 831                 }
 832
 833                 ret = dwarf_lowpc(die->dwarf_die, &low_addr);
 834                 if (ret) {
 835                         free(die_name);
 836                         goto error;
 837                 }
 838
 839                 ret = bin_info_append_offset_str(die_name, low_addr, addr,
 840                                                 func_name);
 841                 free(die_name);
 842                 if (ret) {
 843                         goto error;
 844                 }
 845         }
 846
 847         bt_dwarf_die_destroy(die);
 848         return 0;
 849
 850 error:
 851         bt_dwarf_die_destroy(die);
 852         return -1;
 853 }
 854
 855 /**
 856  * Get the name of the function containing a given address within an
 857  * executable using DWARF debug info.
 858  *
 859  * If found, the out parameter `func_name` is set on success. On
 860  * failure, it remains unchanged.
 861  *
 862  * @param bin           bin_info instance for the executable containing
 863  *                      the address
 864  * @param addr          Virtual memory address for which to find the
 865  *                      function name
 866  * @param func_name     Out parameter, the function name
 867  * @returns             0 on success, -1 on failure
 868  */
 869 static
 870 int bin_info_lookup_dwarf_function_name(struct bin_info *bin, uint64_t addr,
 871                 char **func_name)
 872 {
 873         int ret = 0;
 874         char *_func_name = NULL;
 875         struct bt_dwarf_cu *cu = NULL;
 876
 877         if (!bin || !func_name) {
 878                 goto error;
 879         }
 880
 881         cu = bt_dwarf_cu_create(bin->dwarf_info);
 882         if (!cu) {
 883                 goto error;
 884         }
 885
 886         while (bt_dwarf_cu_next(cu) == 0) {
 887                 ret = bin_info_lookup_cu_function_name(cu, addr, &_func_name);
 888                 if (ret) {
 889                         goto error;
 890                 }
 891
 892                 if (_func_name) {
 893                         break;
 894                 }
 895         }
 896
 897         if (_func_name) {
 898                 *func_name = _func_name;
 899         } else {
 900                 goto error;
 901         }
 902
 903         bt_dwarf_cu_destroy(cu);
 904         return 0;
 905
 906 error:
 907         bt_dwarf_cu_destroy(cu);
 908         return -1;
 909 }
 910
 911 BT_HIDDEN
 912 int bin_info_lookup_function_name(struct bin_info *bin, uint64_t addr,
 913                 char **func_name)
 914 {
 915         int ret = 0;
 916         char *_func_name = NULL;
 917
 918         if (!bin || !func_name) {
 919                 goto error;
 920         }
 921
 922         /* Set DWARF info if it hasn't been accessed yet. */
 923         if (!bin->dwarf_info && !bin->is_elf_only) {
 924                 ret = bin_info_set_dwarf_info(bin);
 925                 if (ret) {
 926                         printf_verbose("Failed to set bin dwarf info, falling back to ELF lookup.\n");
 927                         /* Failed to set DWARF info, fallback to ELF. */
 928                         bin->is_elf_only = true;
 929                 }
 930         }
 931
 932         if (!bin_info_has_address(bin, addr)) {
 933                 goto error;
 934         }
 935
 936         /*
 937          * Addresses in ELF and DWARF are relative to base address for
 938          * PIC, so make the address argument relative too if needed.
 939          */
 940         if (bin->is_pic) {
 941                 addr -= bin->low_addr;
 942         }
 943
 944         if (bin->is_elf_only) {
 945                 ret = bin_info_lookup_elf_function_name(bin, addr, &_func_name);
 946                 printf_verbose("Failed to lookup function name (elf), error %i\n", ret);
 947         } else {
 948                 ret = bin_info_lookup_dwarf_function_name(bin, addr, &_func_name);
 949                 printf_verbose("Failed to lookup function name (dwarf), error %i\n", ret);
 950         }
 951
 952         *func_name = _func_name;
 953         return 0;
 954
 955 error:
 956         return -1;
 957 }
 958
 959 BT_HIDDEN
 960 int bin_info_get_bin_loc(struct bin_info *bin, uint64_t addr, char **bin_loc)
 961 {
 962         int ret = 0;
 963         char *_bin_loc = NULL;
 964
 965         if (!bin || !bin_loc) {
 966                 goto error;
 967         }
 968
 969         if (bin->is_pic) {
 970                 addr -= bin->low_addr;
 971                 ret = asprintf(&_bin_loc, "+%#0" PRIx64, addr);
 972         } else {
 973                 ret = asprintf(&_bin_loc, "@%#0" PRIx64, addr);
 974         }
 975
 976         if (ret == -1 || !_bin_loc) {
 977                 goto error;
 978         }
 979
 980         *bin_loc = _bin_loc;
 981         return 0;
 982
 983 error:
 984         return -1;
 985 }
 986
 987 /**
 988  * Predicate used to determine whether the children of a given DIE
 989  * contain a specific address.
 990  *
 991  * More specifically, the parameter `die` is expected to be a
 992  * subprogram (function) DIE, and this predicate tells whether any
 993  * subroutines are inlined within this function and would contain
 994  * `addr`.
 995  *
 996  * On success, the out parameter `contains` is set with the boolean
 997  * value indicating whether the DIE's range covers `addr`. On failure,
 998  * it remains unchanged.
 999  *
1000  * Do note that this function advances the position of `die`. If the
1001  * address is found within one of its children, `die` will be pointing
1002  * to that child upon returning from the function, allowing to extract
1003  * the information deemed necessary.
1004  *
1005  * @param die           The parent DIE in whose children the address will be
1006  *                      looked for
1007  * @param addr          The address for which to look for in the DIEs
1008  * @param contains      Out parameter, true if addr is contained,
1009  *                      false if not
1010  * @returns             Returns 0 on success, -1 on failure
1011  */
1012 static
1013 int bin_info_child_die_has_address(struct bt_dwarf_die *die, uint64_t addr, bool *contains)
1014 {
1015         int ret = 0;
1016         bool _contains = false;
1017
1018         if (!die) {
1019                 goto error;
1020         }
1021
1022         ret = bt_dwarf_die_child(die);
1023         if (ret) {
1024                 goto error;
1025         }
1026
1027         do {
1028                 int tag;
1029
1030                 ret = bt_dwarf_die_get_tag(die, &tag);
1031                 if (ret) {
1032                         goto error;
1033                 }
1034
1035                 if (tag == DW_TAG_inlined_subroutine) {
1036                         ret = bt_dwarf_die_contains_addr(die, addr, &_contains);
1037                         if (ret) {
1038                                 goto error;
1039                         }
1040
1041                         if (_contains) {
1042                                 goto end;
1043                         }
1044                 }
1045         } while (bt_dwarf_die_next(die) == 0);
1046
1047 end:
1048         *contains = _contains;
1049         return 0;
1050
1051 error:
1052         return -1;
1053 }
1054
1055 /**
1056  * Lookup the source location for a given address within a CU, making
1057  * the assumption that it is contained within an inline routine in a
1058  * function.
1059  *
1060  * @param cu            bt_dwarf_cu instance in which to look for the address
1061  * @param addr          The address for which to look for
1062  * @param src_loc       Out parameter, the source location (filename and
1063  *                      line number) for the address
1064  * @returns             0 on success, -1 on failure
1065  */
1066 static
1067 int bin_info_lookup_cu_src_loc_inl(struct bt_dwarf_cu *cu, uint64_t addr,
1068                 struct source_location **src_loc)
1069 {
1070         int ret = 0;
1071         bool found = false;
1072         struct bt_dwarf_die *die = NULL;
1073         struct source_location *_src_loc = NULL;
1074
1075         if (!cu || !src_loc) {
1076                 goto error;
1077         }
1078
1079         die = bt_dwarf_die_create(cu);
1080         if (!die) {
1081                 goto error;
1082         }
1083
1084         while (bt_dwarf_die_next(die) == 0) {
1085                 int tag;
1086
1087                 ret = bt_dwarf_die_get_tag(die, &tag);
1088                 if (ret) {
1089                         goto error;
1090                 }
1091
1092                 if (tag == DW_TAG_subprogram) {
1093                         bool contains = false;
1094
1095                         ret = bt_dwarf_die_contains_addr(die, addr, &contains);
1096                         if (ret) {
1097                                 goto error;
1098                         }
1099
1100                         if (contains) {
1101                                 /*
1102                                  * Try to find an inlined subroutine
1103                                  * child of this DIE containing addr.
1104                                  */
1105                                 ret = bin_info_child_die_has_address(die, addr,
1106                                                 &found);
1107                                 if(ret) {
1108                                         goto error;
1109                                 }
1110
1111                                 goto end;
1112                         }
1113                 }
1114         }
1115
1116 end:
1117         if (found) {
1118                 char *filename = NULL;
1119                 uint64_t line_no;
1120
1121                 _src_loc = g_new0(struct source_location, 1);
1122                 if (!_src_loc) {
1123                         goto error;
1124                 }
1125
1126                 ret = bt_dwarf_die_get_call_file(die, &filename);
1127                 if (ret) {
1128                         goto error;
1129                 }
1130                 ret = bt_dwarf_die_get_call_line(die, &line_no);
1131                 if (ret) {
1132                         free(filename);
1133                         goto error;
1134                 }
1135
1136                 _src_loc->filename = filename;
1137                 _src_loc->line_no = line_no;
1138                 *src_loc = _src_loc;
1139         }
1140
1141         bt_dwarf_die_destroy(die);
1142         return 0;
1143
1144 error:
1145         source_location_destroy(_src_loc);
1146         bt_dwarf_die_destroy(die);
1147         return -1;
1148 }
1149
1150 /**
1151  * Lookup the source location for a given address within a CU,
1152  * assuming that it is contained within an inlined function.
1153  *
1154  * A source location can be found regardless of inlining status for
1155  * this method, but in the case of an inlined function, the returned
1156  * source location will point not to the callsite but rather to the
1157  * definition site of the inline function.
1158  *
1159  * @param cu            bt_dwarf_cu instance in which to look for the address
1160  * @param addr          The address for which to look for
1161  * @param src_loc       Out parameter, the source location (filename and
1162  *                      line number) for the address
1163  * @returns             0 on success, -1 on failure
1164  */
1165 static
1166 int bin_info_lookup_cu_src_loc_no_inl(struct bt_dwarf_cu *cu, uint64_t addr,
1167                 struct source_location **src_loc)
1168 {
1169         struct source_location *_src_loc = NULL;
1170         struct bt_dwarf_die *die = NULL;
1171         const char *filename = NULL;
1172         Dwarf_Line *line = NULL;
1173         Dwarf_Addr line_addr;
1174         int ret, line_no;
1175
1176         if (!cu || !src_loc) {
1177                 goto error;
1178         }
1179
1180         die = bt_dwarf_die_create(cu);
1181         if (!die) {
1182                 goto error;
1183         }
1184
1185         line = dwarf_getsrc_die(die->dwarf_die, addr);
1186         if (!line) {
1187                 goto error;
1188         }
1189
1190         ret = dwarf_lineaddr(line, &line_addr);
1191         if (ret) {
1192                 goto error;
1193         }
1194
1195         filename = dwarf_linesrc(line, NULL, NULL);
1196         if (!filename) {
1197                 goto error;
1198         }
1199
1200         if (addr == line_addr) {
1201                 _src_loc = g_new0(struct source_location, 1);
1202                 if (!_src_loc) {
1203                         goto error;
1204                 }
1205
1206                 ret = dwarf_lineno(line, &line_no);
1207                 if (ret) {
1208                         goto error;
1209                 }
1210
1211                 _src_loc->line_no = line_no;
1212                 _src_loc->filename = strdup(filename);
1213         }
1214
1215         bt_dwarf_die_destroy(die);
1216
1217         if (_src_loc) {
1218                 *src_loc = _src_loc;
1219         }
1220
1221         return 0;
1222
1223 error:
1224         source_location_destroy(_src_loc);
1225         bt_dwarf_die_destroy(die);
1226         return -1;
1227 }
1228
1229 /**
1230  * Get the source location (file name and line number) for a given
1231  * address within a compile unit (CU).
1232  *
1233  * On success, the out parameter `src_loc` is set if found. On
1234  * failure, it remains unchanged.
1235  *
1236  * @param cu            bt_dwarf_cu instance for the compile unit which
1237  *                      may contain the address
1238  * @param addr          Virtual memory address for which to find the
1239  *                      source location
1240  * @param src_loc       Out parameter, the source location
1241  * @returns             0 on success, -1 on failure
1242  */
1243 static
1244 int bin_info_lookup_cu_src_loc(struct bt_dwarf_cu *cu, uint64_t addr,
1245                 struct source_location **src_loc)
1246 {
1247         int ret = 0;
1248         struct source_location *_src_loc = NULL;
1249
1250         if (!cu || !src_loc) {
1251                 goto error;
1252         }
1253
1254         ret = bin_info_lookup_cu_src_loc_inl(cu, addr, &_src_loc);
1255         if (ret) {
1256                 goto error;
1257         }
1258
1259         if (_src_loc) {
1260                 goto end;
1261         }
1262
1263         ret = bin_info_lookup_cu_src_loc_no_inl(cu, addr, &_src_loc);
1264         if (ret) {
1265                 goto error;
1266         }
1267
1268         if (_src_loc) {
1269                 goto end;
1270         }
1271
1272 end:
1273         if (_src_loc) {
1274                 *src_loc = _src_loc;
1275         }
1276
1277         return 0;
1278
1279 error:
1280         source_location_destroy(_src_loc);
1281         return -1;
1282 }
1283
1284 BT_HIDDEN
1285 int bin_info_lookup_source_location(struct bin_info *bin, uint64_t addr,
1286                 struct source_location **src_loc)
1287 {
1288         struct bt_dwarf_cu *cu = NULL;
1289         struct source_location *_src_loc = NULL;
1290
1291         if (!bin || !src_loc) {
1292                 goto error;
1293         }
1294
1295         /* Set DWARF info if it hasn't been accessed yet. */
1296         if (!bin->dwarf_info && !bin->is_elf_only) {
1297                 if (bin_info_set_dwarf_info(bin)) {
1298                         /* Failed to set DWARF info. */
1299                         bin->is_elf_only = true;
1300                 }
1301         }
1302
1303         if (bin->is_elf_only) {
1304                 /* We cannot lookup source location without DWARF info. */
1305                 goto error;
1306         }
1307
1308         if (!bin_info_has_address(bin, addr)) {
1309                 goto error;
1310         }
1311
1312         /*
1313          * Addresses in ELF and DWARF are relative to base address for
1314          * PIC, so make the address argument relative too if needed.
1315          */
1316         if (bin->is_pic) {
1317                 addr -= bin->low_addr;
1318         }
1319
1320         cu = bt_dwarf_cu_create(bin->dwarf_info);
1321         if (!cu) {
1322                 goto error;
1323         }
1324
1325         while (bt_dwarf_cu_next(cu) == 0) {
1326                 int ret;
1327
1328                 ret = bin_info_lookup_cu_src_loc(cu, addr, &_src_loc);
1329                 if (ret) {
1330                         goto error;
1331                 }
1332
1333                 if (_src_loc) {
1334                         break;
1335                 }
1336         }
1337
1338         bt_dwarf_cu_destroy(cu);
1339         if (_src_loc) {
1340                 *src_loc = _src_loc;
1341         }
1342
1343         return 0;
1344
1345 error:
1346         source_location_destroy(_src_loc);
1347         bt_dwarf_cu_destroy(cu);
1348         return -1;
1349 }