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