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c40a57e5 AB |
1 | /* |
2 | * so-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/so-info.h> | |
41 | #include <babeltrace/crc32.h> | |
42 | #include <babeltrace/babeltrace-internal.h> | |
43 | ||
44 | /* | |
45 | * An address printed in hex is at most 20 bytes (16 for 64-bits + | |
46 | * leading 0x + optional leading '+' if addr is an offset + null | |
47 | * character). | |
48 | */ | |
49 | #define ADDR_STR_LEN 20 | |
50 | ||
51 | BT_HIDDEN | |
52 | int so_info_init(void) | |
53 | { | |
54 | int ret = 0; | |
55 | ||
56 | if (elf_version(EV_CURRENT) == EV_NONE) { | |
57 | fprintf(stderr, "ELF library initialization failed: %s\n", | |
58 | elf_errmsg(-1)); | |
59 | ret = -1; | |
60 | } | |
61 | ||
62 | return ret; | |
63 | } | |
64 | ||
65 | BT_HIDDEN | |
66 | struct so_info *so_info_create(const char *path, uint64_t low_addr, | |
67 | uint64_t memsz) | |
68 | { | |
69 | struct so_info *so = NULL; | |
70 | GElf_Ehdr *ehdr = NULL; | |
71 | ||
72 | if (!path) { | |
73 | goto error; | |
74 | } | |
75 | ||
76 | so = g_new0(struct so_info, 1); | |
77 | if (!so) { | |
78 | goto error; | |
79 | } | |
80 | ||
81 | so->elf_path = strdup(path); | |
82 | if (!so->elf_path) { | |
83 | goto error; | |
84 | } | |
85 | ||
86 | so->elf_fd = open(path, O_RDONLY); | |
87 | if (so->elf_fd < 0) { | |
88 | fprintf(stderr, "Failed to open %s\n", path); | |
89 | goto error; | |
90 | } | |
91 | ||
92 | so->elf_file = elf_begin(so->elf_fd, ELF_C_READ, NULL); | |
93 | if (!so->elf_file) { | |
94 | fprintf(stderr, "elf_begin failed: %s\n", elf_errmsg(-1)); | |
95 | goto error; | |
96 | } | |
97 | ||
98 | if (elf_kind(so->elf_file) != ELF_K_ELF) { | |
99 | fprintf(stderr, "Error: %s is not an ELF object\n", | |
100 | so->elf_path); | |
101 | goto error; | |
102 | } | |
103 | ||
104 | ehdr = g_new0(GElf_Ehdr, 1); | |
105 | if (!ehdr) { | |
106 | goto error; | |
107 | } | |
108 | ||
109 | if (!gelf_getehdr(so->elf_file, ehdr)) { | |
110 | fprintf(stderr, "Error: couldn't get ehdr for %s\n", | |
111 | so->elf_path); | |
112 | goto error; | |
113 | } | |
114 | ||
115 | /* Position independent code has an e_type value of ET_DYN. */ | |
116 | so->is_pic = ehdr->e_type == ET_DYN; | |
117 | so->memsz = memsz; | |
118 | so->low_addr = low_addr; | |
119 | so->high_addr = so->low_addr + so->memsz; | |
120 | ||
121 | g_free(ehdr); | |
122 | return so; | |
123 | ||
124 | error: | |
125 | g_free(ehdr); | |
126 | so_info_destroy(so); | |
127 | return NULL; | |
128 | } | |
129 | ||
130 | BT_HIDDEN | |
131 | void so_info_destroy(struct so_info *so) | |
132 | { | |
133 | if (!so) { | |
134 | return; | |
135 | } | |
136 | ||
137 | dwarf_end(so->dwarf_info); | |
138 | ||
139 | free(so->elf_path); | |
140 | free(so->dwarf_path); | |
141 | free(so->build_id); | |
142 | free(so->dbg_link_filename); | |
143 | ||
144 | elf_end(so->elf_file); | |
145 | ||
146 | close(so->elf_fd); | |
147 | close(so->dwarf_fd); | |
148 | ||
149 | g_free(so); | |
150 | } | |
151 | ||
152 | BT_HIDDEN | |
153 | int so_info_set_build_id(struct so_info *so, uint8_t *build_id, | |
154 | size_t build_id_len) | |
155 | { | |
156 | if (!so || !build_id) { | |
157 | goto error; | |
158 | } | |
159 | ||
160 | so->build_id = malloc(build_id_len); | |
161 | if (!so->build_id) { | |
162 | goto error; | |
163 | } | |
164 | ||
165 | memcpy(so->build_id, build_id, build_id_len); | |
166 | so->build_id_len = build_id_len; | |
167 | ||
168 | /* | |
169 | * Reset the is_elf_only flag in case it had been set | |
170 | * previously, because we might find separate debug info using | |
171 | * the new build id information. | |
172 | */ | |
173 | so->is_elf_only = false; | |
174 | ||
175 | return 0; | |
176 | ||
177 | error: | |
178 | ||
179 | return -1; | |
180 | } | |
181 | ||
182 | BT_HIDDEN | |
183 | int so_info_set_debug_link(struct so_info *so, char *filename, uint32_t crc) | |
184 | { | |
185 | if (!so || !filename) { | |
186 | goto error; | |
187 | } | |
188 | ||
189 | so->dbg_link_filename = strdup(filename); | |
190 | if (!so->dbg_link_filename) { | |
191 | goto error; | |
192 | } | |
193 | ||
194 | so->dbg_link_crc = crc; | |
195 | ||
196 | /* | |
197 | * Reset the is_elf_only flag in case it had been set | |
198 | * previously, because we might find separate debug info using | |
199 | * the new build id information. | |
200 | */ | |
201 | so->is_elf_only = false; | |
202 | ||
203 | return 0; | |
204 | ||
205 | error: | |
206 | ||
207 | return -1; | |
208 | } | |
209 | ||
210 | /** | |
211 | * Tries to read DWARF info from the location given by path, and | |
212 | * attach it to the given so_info instance if it exists. | |
213 | * | |
214 | * @param so so_info instance for which to set DWARF info | |
215 | * @param path Presumed location of the DWARF info | |
216 | * @returns 0 on success, -1 on failure | |
217 | */ | |
218 | static | |
219 | int so_info_set_dwarf_info_from_path(struct so_info *so, char *path) | |
220 | { | |
221 | int fd = -1, ret = 0; | |
222 | struct bt_dwarf_cu *cu = NULL; | |
223 | Dwarf *dwarf_info = NULL; | |
224 | ||
225 | if (!so || !path) { | |
226 | goto error; | |
227 | } | |
228 | ||
229 | fd = open(path, O_RDONLY); | |
230 | if (fd < 0) { | |
231 | goto error; | |
232 | } | |
233 | ||
234 | dwarf_info = dwarf_begin(fd, DWARF_C_READ); | |
235 | if (!dwarf_info) { | |
236 | goto error; | |
237 | } | |
238 | ||
239 | /* | |
240 | * Check if the dwarf info has any CU. If not, the SO's object | |
241 | * file contains no DWARF info. | |
242 | */ | |
243 | cu = bt_dwarf_cu_create(dwarf_info); | |
244 | if (!cu) { | |
245 | goto error; | |
246 | } | |
247 | ||
248 | ret = bt_dwarf_cu_next(cu); | |
249 | if (ret) { | |
250 | goto error; | |
251 | } | |
252 | ||
253 | so->dwarf_fd = fd; | |
254 | so->dwarf_path = strdup(path); | |
255 | if (!so->dwarf_path) { | |
256 | goto error; | |
257 | } | |
258 | so->dwarf_info = dwarf_info; | |
259 | free(cu); | |
260 | ||
261 | return 0; | |
262 | ||
263 | error: | |
264 | close(fd); | |
265 | dwarf_end(dwarf_info); | |
266 | g_free(dwarf_info); | |
267 | free(cu); | |
268 | ||
269 | return -1; | |
270 | } | |
271 | ||
272 | /** | |
273 | * Try to set the dwarf_info for a given so_info instance via the | |
274 | * build ID method. | |
275 | * | |
276 | * @param so so_info instance for which to retrieve the | |
277 | * DWARF info via build ID | |
278 | * @returns 0 on success (i.e. dwarf_info set), -1 on failure | |
279 | */ | |
280 | static | |
281 | int so_info_set_dwarf_info_build_id(struct so_info *so) | |
282 | { | |
283 | int i = 0, ret = 0, dbg_dir_trailing_slash = 0; | |
284 | char *path = NULL, *build_id_file = NULL; | |
285 | const char *dbg_dir = NULL; | |
286 | size_t build_id_file_len, path_len; | |
287 | ||
288 | if (!so || !so->build_id) { | |
289 | goto error; | |
290 | } | |
291 | ||
292 | dbg_dir = opt_debug_dir ? : DEFAULT_DEBUG_DIR; | |
293 | ||
294 | dbg_dir_trailing_slash = dbg_dir[strlen(dbg_dir) - 1] == '/'; | |
295 | ||
296 | /* 2 characters per byte printed in hex, +2 for '/' and '\0' */ | |
297 | build_id_file_len = (2 * so->build_id_len) + 2; | |
298 | build_id_file = malloc(build_id_file_len); | |
299 | if (!build_id_file) { | |
300 | goto error; | |
301 | } | |
302 | ||
303 | snprintf(build_id_file, 4, "%02x/", so->build_id[0]); | |
304 | for (i = 1; i < so->build_id_len; ++i) { | |
305 | int path_idx = 3 + 2 * (i - 1); | |
306 | ||
307 | snprintf(&build_id_file[path_idx], 3, "%02x", so->build_id[i]); | |
308 | } | |
309 | ||
310 | path_len = strlen(dbg_dir) + strlen(BUILD_ID_SUBDIR) + | |
311 | strlen(build_id_file) + strlen(BUILD_ID_SUFFIX) + 1; | |
312 | if (!dbg_dir_trailing_slash) { | |
313 | path_len += 1; | |
314 | } | |
315 | ||
316 | path = malloc(path_len); | |
317 | if (!path) { | |
318 | goto error; | |
319 | } | |
320 | ||
321 | strcpy(path, dbg_dir); | |
322 | if (!dbg_dir_trailing_slash) { | |
323 | strcat(path, "/"); | |
324 | } | |
325 | strcat(path, BUILD_ID_SUBDIR); | |
326 | strcat(path, build_id_file); | |
327 | strcat(path, BUILD_ID_SUFFIX); | |
328 | ||
329 | ret = so_info_set_dwarf_info_from_path(so, path); | |
330 | if (ret) { | |
331 | goto error; | |
332 | } | |
333 | ||
334 | goto end; | |
335 | ||
336 | error: | |
337 | ret = -1; | |
338 | end: | |
339 | free(build_id_file); | |
340 | free(path); | |
341 | ||
342 | return ret; | |
343 | } | |
344 | ||
345 | /** | |
346 | * Tests whether the file located at path exists and has the expected | |
347 | * checksum. | |
348 | * | |
349 | * This predicate is used when looking up separate debug info via the | |
350 | * GNU debuglink method. The expected crc can be found .gnu_debuglink | |
351 | * section in the original ELF file, along with the filename for the | |
352 | * file containing the debug info. | |
353 | * | |
354 | * @param path Full path at which to look for the debug file | |
355 | * @param crc Expected checksum for the debug file | |
356 | * @returns 1 if the file exists and has the correct checksum, | |
357 | * 0 otherwise | |
358 | */ | |
359 | static | |
360 | int is_valid_debug_file(char *path, uint32_t crc) | |
361 | { | |
362 | int ret = 0, fd = -1; | |
363 | uint32_t _crc = 0; | |
364 | ||
365 | if (!path) { | |
366 | goto end; | |
367 | } | |
368 | ||
369 | fd = open(path, O_RDONLY); | |
370 | if (fd < 0) { | |
371 | goto end; | |
372 | } | |
373 | ||
374 | ret = crc32(fd, &_crc); | |
375 | if (ret) { | |
376 | ret = 0; | |
377 | goto end; | |
378 | } | |
379 | ||
380 | ret = (crc == _crc); | |
381 | ||
382 | end: | |
383 | close(fd); | |
384 | return ret; | |
385 | } | |
386 | ||
387 | /** | |
388 | * Try to set the dwarf_info for a given so_info instance via the | |
389 | * build ID method. | |
390 | * | |
391 | * @param so so_info instance for which to retrieve the | |
392 | * DWARF info via debug link | |
393 | * @returns 0 on success (i.e. dwarf_info set), -1 on failure | |
394 | */ | |
395 | static | |
396 | int so_info_set_dwarf_info_debug_link(struct so_info *so) | |
397 | { | |
398 | int ret = 0; | |
399 | const char *dbg_dir = NULL; | |
400 | char *dir_name = NULL, *so_dir = NULL, *path = NULL; | |
401 | size_t max_path_len = 0; | |
402 | ||
403 | if (!so || !so->dbg_link_filename) { | |
404 | goto error; | |
405 | } | |
406 | ||
407 | dbg_dir = opt_debug_dir ? : DEFAULT_DEBUG_DIR; | |
408 | ||
409 | dir_name = dirname(so->elf_path); | |
410 | if (!dir_name) { | |
411 | goto error; | |
412 | } | |
413 | ||
414 | /* so_dir is just dir_name with a trailing slash */ | |
415 | so_dir = malloc(strlen(dir_name) + 2); | |
416 | if (!so_dir) { | |
417 | goto error; | |
418 | } | |
419 | ||
420 | strcpy(so_dir, dir_name); | |
421 | strcat(so_dir, "/"); | |
422 | ||
423 | max_path_len = strlen(dbg_dir) + strlen(so_dir) + | |
424 | strlen(DEBUG_SUBDIR) + strlen(so->dbg_link_filename) | |
425 | + 1; | |
426 | path = malloc(max_path_len); | |
427 | if (!path) { | |
428 | goto error; | |
429 | } | |
430 | ||
431 | /* First look in the SO's dir */ | |
432 | strcpy(path, so_dir); | |
433 | strcat(path, so->dbg_link_filename); | |
434 | ||
435 | if (is_valid_debug_file(path, so->dbg_link_crc)) { | |
436 | goto found; | |
437 | } | |
438 | ||
439 | /* If not found, look in .debug subdir */ | |
440 | strcpy(path, so_dir); | |
441 | strcat(path, DEBUG_SUBDIR); | |
442 | strcat(path, so->dbg_link_filename); | |
443 | ||
444 | if (is_valid_debug_file(path, so->dbg_link_crc)) { | |
445 | goto found; | |
446 | } | |
447 | ||
448 | /* Lastly, look under the global debug directory */ | |
449 | strcpy(path, dbg_dir); | |
450 | strcat(path, so_dir); | |
451 | strcat(path, so->dbg_link_filename); | |
452 | ||
453 | if (is_valid_debug_file(path, so->dbg_link_crc)) { | |
454 | goto found; | |
455 | } | |
456 | ||
457 | error: | |
458 | ret = -1; | |
459 | end: | |
460 | free(path); | |
461 | free(so_dir); | |
462 | ||
463 | return ret; | |
464 | ||
465 | found: | |
466 | ret = so_info_set_dwarf_info_from_path(so, path); | |
467 | if (ret) { | |
468 | goto error; | |
469 | } | |
470 | ||
471 | goto end; | |
472 | } | |
473 | ||
474 | /** | |
475 | * Initialize the DWARF info for a given executable. | |
476 | * | |
477 | * @param so so_info instance | |
478 | * @returns 0 on success, -1 on failure | |
479 | */ | |
480 | static | |
481 | int so_info_set_dwarf_info(struct so_info *so) | |
482 | { | |
483 | int ret = 0; | |
484 | ||
485 | if (!so) { | |
486 | goto error; | |
487 | } | |
488 | ||
489 | /* First try to set the DWARF info from the ELF file */ | |
490 | ret = so_info_set_dwarf_info_from_path(so, so->elf_path); | |
491 | if (!ret) { | |
492 | goto end; | |
493 | } | |
494 | ||
495 | /* | |
496 | * If that fails, try to find separate debug info via build ID | |
497 | * and debug link. | |
498 | */ | |
499 | ret = so_info_set_dwarf_info_build_id(so); | |
500 | if (!ret) { | |
501 | goto end; | |
502 | } | |
503 | ||
504 | ret = so_info_set_dwarf_info_debug_link(so); | |
505 | if (!ret) { | |
506 | goto end; | |
507 | } | |
508 | ||
509 | error: | |
510 | ret = -1; | |
511 | end: | |
512 | return ret; | |
513 | } | |
514 | ||
515 | BT_HIDDEN | |
516 | void source_location_destroy(struct source_location *src_loc) | |
517 | { | |
518 | if (!src_loc) { | |
519 | return; | |
520 | } | |
521 | ||
522 | free(src_loc->filename); | |
523 | g_free(src_loc); | |
524 | } | |
525 | ||
526 | /** | |
527 | * Try to find the symbol closest to an address within a given ELF | |
528 | * section. | |
529 | * | |
530 | * Only function symbols are taken into account. The symbol's address | |
531 | * must precede `addr`. A symbol with a closer address might exist | |
532 | * after `addr` but is irrelevant because it cannot encompass `addr`. | |
533 | * | |
534 | * On success, if found, the out parameters `sym` and `shdr` are | |
535 | * set. On failure or if none are found, they remain unchanged. | |
536 | * | |
537 | * @param scn ELF section in which to look for the address | |
538 | * @param addr Virtual memory address for which to find the | |
539 | * nearest function symbol | |
540 | * @param sym Out parameter, the nearest function symbol | |
541 | * @param shdr Out parameter, the section header for scn | |
542 | * @returns 0 on success, -1 on failure | |
543 | */ | |
544 | static | |
545 | int so_info_get_nearest_symbol_from_section(Elf_Scn *scn, uint64_t addr, | |
546 | GElf_Sym **sym, GElf_Shdr **shdr) | |
547 | { | |
548 | int i; | |
549 | size_t symbol_count; | |
550 | Elf_Data *data = NULL; | |
551 | GElf_Shdr *_shdr = NULL; | |
552 | GElf_Sym *nearest_sym = NULL; | |
553 | ||
554 | if (!scn || !sym || !shdr) { | |
555 | goto error; | |
556 | } | |
557 | ||
558 | _shdr = g_new0(GElf_Shdr, 1); | |
559 | if (!_shdr) { | |
560 | goto error; | |
561 | } | |
562 | ||
563 | _shdr = gelf_getshdr(scn, _shdr); | |
564 | if (!_shdr) { | |
565 | goto error; | |
566 | } | |
567 | ||
568 | if (_shdr->sh_type != SHT_SYMTAB) { | |
569 | /* | |
570 | * We are only interested in symbol table (symtab) | |
571 | * sections, skip this one. | |
572 | */ | |
573 | goto end; | |
574 | } | |
575 | ||
576 | data = elf_getdata(scn, NULL); | |
577 | if (!data) { | |
578 | goto error; | |
579 | } | |
580 | ||
581 | symbol_count = _shdr->sh_size / _shdr->sh_entsize; | |
582 | ||
583 | for (i = 0; i < symbol_count; ++i) { | |
584 | GElf_Sym *cur_sym = NULL; | |
585 | ||
586 | cur_sym = g_new0(GElf_Sym, 1); | |
587 | if (!cur_sym) { | |
588 | goto error; | |
589 | } | |
590 | cur_sym = gelf_getsym(data, i, cur_sym); | |
591 | if (!cur_sym) { | |
592 | goto error; | |
593 | } | |
594 | if (GELF_ST_TYPE(cur_sym->st_info) != STT_FUNC) { | |
595 | /* We're only interested in the functions. */ | |
596 | g_free(cur_sym); | |
597 | continue; | |
598 | } | |
599 | ||
600 | if (cur_sym->st_value <= addr && | |
601 | (!nearest_sym || | |
602 | cur_sym->st_value > nearest_sym->st_value)) { | |
603 | g_free(nearest_sym); | |
604 | nearest_sym = cur_sym; | |
605 | } else { | |
606 | g_free(cur_sym); | |
607 | } | |
608 | } | |
609 | ||
610 | end: | |
611 | if (nearest_sym) { | |
612 | *sym = nearest_sym; | |
613 | *shdr = _shdr; | |
614 | } else { | |
615 | g_free(_shdr); | |
616 | } | |
617 | ||
618 | return 0; | |
619 | ||
620 | error: | |
621 | g_free(nearest_sym); | |
622 | g_free(_shdr); | |
623 | return -1; | |
624 | } | |
625 | ||
626 | /** | |
627 | * Get the name of the function containing a given address within an | |
628 | * executable using ELF symbols. | |
629 | * | |
630 | * The function name is in fact the name of the nearest ELF symbol, | |
631 | * followed by the offset in bytes between the address and the symbol | |
632 | * (in hex), separated by a '+' character. | |
633 | * | |
634 | * If found, the out parameter `func_name` is set on success. On failure, | |
635 | * it remains unchanged. | |
636 | * | |
637 | * @param so so_info instance for the executable containing | |
638 | * the address | |
639 | * @param addr Virtual memory address for which to find the | |
640 | * function name | |
641 | * @param func_name Out parameter, the function name | |
642 | * @returns 0 on success, -1 on failure | |
643 | */ | |
644 | static | |
645 | int so_info_lookup_elf_function_name(struct so_info *so, uint64_t addr, | |
646 | char **func_name) | |
647 | { | |
648 | /* | |
649 | * TODO (possible optimisation): if an ELF has no symtab | |
650 | * section, it has been stripped. Therefore, it would be wise | |
651 | * to store a flag indicating the stripped status after the | |
652 | * first iteration to prevent subsequent ones. | |
653 | */ | |
654 | int ret = 0; | |
655 | Elf_Scn *scn = NULL; | |
656 | GElf_Sym *sym = NULL; | |
657 | GElf_Shdr *shdr = NULL; | |
658 | char *sym_name = NULL; | |
659 | char *_func_name = NULL; | |
660 | char offset_str[ADDR_STR_LEN]; | |
661 | ||
662 | scn = elf_nextscn(so->elf_file, scn); | |
663 | if (!scn) { | |
664 | goto error; | |
665 | } | |
666 | ||
667 | while (scn && !sym) { | |
668 | ret = so_info_get_nearest_symbol_from_section( | |
669 | scn, addr, &sym, &shdr); | |
670 | if (ret) { | |
671 | goto error; | |
672 | } | |
673 | ||
674 | scn = elf_nextscn(so->elf_file, scn); | |
675 | } | |
676 | ||
677 | if (sym) { | |
678 | sym_name = elf_strptr(so->elf_file, shdr->sh_link, | |
679 | sym->st_name); | |
680 | if (!sym_name) { | |
681 | goto error; | |
682 | } | |
683 | ||
684 | snprintf(offset_str, ADDR_STR_LEN, "+%#0" PRIx64, | |
685 | addr - sym->st_value); | |
686 | _func_name = malloc(strlen(sym_name) + ADDR_STR_LEN); | |
687 | if (!_func_name) { | |
688 | goto error; | |
689 | } | |
690 | ||
691 | strcpy(_func_name, sym_name); | |
692 | strcat(_func_name, offset_str); | |
693 | *func_name = _func_name; | |
694 | } | |
695 | ||
696 | g_free(shdr); | |
697 | g_free(sym); | |
698 | return 0; | |
699 | ||
700 | error: | |
701 | g_free(shdr); | |
702 | g_free(sym); | |
703 | free(_func_name); | |
704 | return -1; | |
705 | } | |
706 | ||
707 | /** | |
708 | * Get the name of the function containing a given address within a | |
709 | * given compile unit (CU). | |
710 | * | |
711 | * If found, the out parameter `func_name` is set on success. On | |
712 | * failure, it remains unchanged. | |
713 | * | |
714 | * @param cu bt_dwarf_cu instance which may contain the address | |
715 | * @param addr Virtual memory address for which to find the | |
716 | * function name | |
717 | * @param func_name Out parameter, the function name | |
718 | * @returns 0 on success, -1 on failure | |
719 | */ | |
720 | static | |
721 | int so_info_lookup_cu_function_name(struct bt_dwarf_cu *cu, uint64_t addr, | |
722 | char **func_name) | |
723 | { | |
724 | int ret = 0, found = 0; | |
725 | char *_func_name = NULL; | |
726 | struct bt_dwarf_die *die = NULL; | |
727 | ||
728 | if (!cu || !func_name) { | |
729 | goto error; | |
730 | } | |
731 | ||
732 | die = bt_dwarf_die_create(cu); | |
733 | if (!die) { | |
734 | goto error; | |
735 | } | |
736 | ||
737 | while (bt_dwarf_die_next(die) == 0) { | |
738 | int tag; | |
739 | ||
740 | ret = bt_dwarf_die_get_tag(die, &tag); | |
741 | if (ret) { | |
742 | goto error; | |
743 | } | |
744 | ||
745 | if (tag == DW_TAG_subprogram) { | |
746 | ret = bt_dwarf_die_contains_addr(die, addr, &found); | |
747 | if (ret) { | |
748 | goto error; | |
749 | } | |
750 | ||
751 | if (found) { | |
752 | break; | |
753 | } | |
754 | } | |
755 | } | |
756 | ||
757 | if (found) { | |
758 | ret = bt_dwarf_die_get_name(die, &_func_name); | |
759 | if (ret) { | |
760 | goto error; | |
761 | } | |
762 | ||
763 | *func_name = _func_name; | |
764 | } | |
765 | ||
766 | bt_dwarf_die_destroy(die); | |
767 | return 0; | |
768 | ||
769 | error: | |
770 | bt_dwarf_die_destroy(die); | |
771 | return -1; | |
772 | } | |
773 | ||
774 | /** | |
775 | * Get the name of the function containing a given address within an | |
776 | * executable using DWARF debug info. | |
777 | * | |
778 | * If found, the out parameter `func_name` is set on success. On | |
779 | * failure, it remains unchanged. | |
780 | * | |
781 | * @param so so_info instance for the executable containing | |
782 | * the address | |
783 | * @param addr Virtual memory address for which to find the | |
784 | * function name | |
785 | * @param func_name Out parameter, the function name | |
786 | * @returns 0 on success, -1 on failure | |
787 | */ | |
788 | static | |
789 | int so_info_lookup_dwarf_function_name(struct so_info *so, uint64_t addr, | |
790 | char **func_name) | |
791 | { | |
792 | int ret = 0; | |
793 | char *_func_name = NULL; | |
794 | struct bt_dwarf_cu *cu = NULL; | |
795 | ||
796 | if (!so || !func_name) { | |
797 | goto error; | |
798 | } | |
799 | ||
800 | cu = bt_dwarf_cu_create(so->dwarf_info); | |
801 | if (!cu) { | |
802 | goto error; | |
803 | } | |
804 | ||
805 | while (bt_dwarf_cu_next(cu) == 0) { | |
806 | ret = so_info_lookup_cu_function_name(cu, addr, &_func_name); | |
807 | if (ret) { | |
808 | goto error; | |
809 | } | |
810 | ||
811 | if (_func_name) { | |
812 | break; | |
813 | } | |
814 | } | |
815 | ||
816 | if (_func_name) { | |
817 | *func_name = _func_name; | |
818 | } | |
819 | ||
820 | bt_dwarf_cu_destroy(cu); | |
821 | return 0; | |
822 | ||
823 | error: | |
824 | bt_dwarf_cu_destroy(cu); | |
825 | return -1; | |
826 | } | |
827 | ||
828 | BT_HIDDEN | |
829 | int so_info_lookup_function_name(struct so_info *so, uint64_t addr, | |
830 | char **func_name) | |
831 | { | |
832 | int ret = 0; | |
833 | char *_func_name = NULL; | |
834 | ||
835 | if (!so || !func_name) { | |
836 | goto error; | |
837 | } | |
838 | ||
839 | /* Set DWARF info if it hasn't been accessed yet. */ | |
840 | if (!so->dwarf_info && !so->is_elf_only) { | |
841 | ret = so_info_set_dwarf_info(so); | |
842 | if (ret) { | |
843 | /* Failed to set DWARF info, fallback to ELF. */ | |
844 | so->is_elf_only = true; | |
845 | } | |
846 | } | |
847 | ||
848 | if (!so_info_has_address(so, addr)) { | |
849 | goto error; | |
850 | } | |
851 | ||
852 | /* | |
853 | * Addresses in ELF and DWARF are relative to base address for | |
854 | * PIC, so make the address argument relative too if needed. | |
855 | */ | |
856 | if (so->is_pic) { | |
857 | addr -= so->low_addr; | |
858 | } | |
859 | ||
860 | if (so->is_elf_only) { | |
861 | ret = so_info_lookup_elf_function_name(so, addr, &_func_name); | |
862 | } else { | |
863 | ret = so_info_lookup_dwarf_function_name(so, addr, &_func_name); | |
864 | } | |
865 | ||
866 | if (ret) { | |
867 | goto error; | |
868 | } | |
869 | ||
870 | if (_func_name) { | |
871 | *func_name = _func_name; | |
872 | } | |
873 | ||
874 | return 0; | |
875 | ||
876 | error: | |
877 | return -1; | |
878 | } | |
879 | ||
880 | /** | |
881 | * Predicate used to determine whether the children of a given DIE | |
882 | * contain a specific address. | |
883 | * | |
884 | * More specifically, the parameter `die` is expected to be a | |
885 | * subprogram (function) DIE, and this predicate tells whether any | |
886 | * subroutines are inlined within this function and would contain | |
887 | * `addr`. | |
888 | * | |
889 | * Do note that this function advances the position of `die`. If the | |
890 | * address is found within one of its children, `die` will be pointing | |
891 | * to that child upon returning from the function, allowing to extract | |
892 | * the information deemed necessary. | |
893 | * | |
894 | * @param die The parent DIE in whose children the address will be | |
895 | * looked for | |
896 | * @param addr The address for which to look for in the DIEs | |
897 | * @returns Returns 1 if the address was found, 0 if not | |
898 | */ | |
899 | static | |
900 | int so_info_child_die_has_address(struct bt_dwarf_die *die, uint64_t addr) | |
901 | { | |
902 | int ret = 0, contains = 0; | |
903 | ||
904 | if (!die) { | |
905 | goto error; | |
906 | } | |
907 | ||
908 | ret = bt_dwarf_die_child(die); | |
909 | if (ret) { | |
910 | goto error; | |
911 | } | |
912 | ||
913 | do { | |
914 | int tag; | |
915 | ||
916 | ret = bt_dwarf_die_get_tag(die, &tag); | |
917 | if (ret) { | |
918 | goto error; | |
919 | } | |
920 | ||
921 | if (tag == DW_TAG_inlined_subroutine) { | |
922 | ret = bt_dwarf_die_contains_addr(die, addr, &contains); | |
923 | if (ret) { | |
924 | goto error; | |
925 | } | |
926 | ||
927 | if (contains) { | |
928 | ret = 1; | |
929 | goto end; | |
930 | } | |
931 | } | |
932 | } while (bt_dwarf_die_next(die) == 0); | |
933 | ||
934 | end: | |
935 | return ret; | |
936 | ||
937 | error: | |
938 | ret = 0; | |
939 | goto end; | |
940 | } | |
941 | ||
942 | /** | |
943 | * Lookup the source location for a given address within a CU, making | |
944 | * the assumption that it is contained within an inline routine in a | |
945 | * function. | |
946 | * | |
947 | * @param cu bt_dwarf_cu instance in which to look for the address | |
948 | * @param addr The address for which to look for | |
949 | * @param src_loc Out parameter, the source location (filename and | |
950 | * line number) for the address | |
951 | * @returns 0 on success, -1 on failure | |
952 | */ | |
953 | static | |
954 | int so_info_lookup_cu_src_loc_inl(struct bt_dwarf_cu *cu, uint64_t addr, | |
955 | struct source_location **src_loc) | |
956 | { | |
957 | int ret = 0, found = 0; | |
958 | struct bt_dwarf_die *die = NULL; | |
959 | struct source_location *_src_loc = NULL; | |
960 | ||
961 | if (!cu || !src_loc) { | |
962 | goto error; | |
963 | } | |
964 | ||
965 | die = bt_dwarf_die_create(cu); | |
966 | if (!die) { | |
967 | goto error; | |
968 | } | |
969 | ||
970 | while (bt_dwarf_die_next(die) == 0) { | |
971 | int tag; | |
972 | ||
973 | ret = bt_dwarf_die_get_tag(die, &tag); | |
974 | if (ret) { | |
975 | goto error; | |
976 | } | |
977 | ||
978 | if (tag == DW_TAG_subprogram) { | |
979 | int contains = 0; | |
980 | ||
981 | ret = bt_dwarf_die_contains_addr(die, addr, &contains); | |
982 | if (ret) { | |
983 | goto error; | |
984 | } | |
985 | ||
986 | if (contains) { | |
987 | /* | |
988 | * Try to find an inlined subroutine | |
989 | * child of this DIE containing addr. | |
990 | */ | |
991 | found = so_info_child_die_has_address( | |
992 | die, addr); | |
993 | goto end; | |
994 | } | |
995 | } | |
996 | } | |
997 | ||
998 | end: | |
999 | if (found) { | |
1000 | char *filename = NULL; | |
1001 | uint64_t line_no; | |
1002 | ||
1003 | _src_loc = g_new0(struct source_location, 1); | |
1004 | if (!_src_loc) { | |
1005 | goto error; | |
1006 | } | |
1007 | ||
1008 | ret = bt_dwarf_die_get_call_file(die, &filename); | |
1009 | if (ret) { | |
1010 | goto error; | |
1011 | } | |
1012 | ret = bt_dwarf_die_get_call_line(die, &line_no); | |
1013 | if (ret) { | |
1014 | free(filename); | |
1015 | goto error; | |
1016 | } | |
1017 | ||
1018 | _src_loc->filename = filename; | |
1019 | _src_loc->line_no = line_no; | |
1020 | *src_loc = _src_loc; | |
1021 | } | |
1022 | ||
1023 | bt_dwarf_die_destroy(die); | |
1024 | return 0; | |
1025 | ||
1026 | error: | |
1027 | source_location_destroy(_src_loc); | |
1028 | bt_dwarf_die_destroy(die); | |
1029 | return -1; | |
1030 | } | |
1031 | ||
1032 | /** | |
1033 | * Lookup the source location for a given address within a CU, | |
1034 | * assuming that it is contained within an inlined function. | |
1035 | * | |
1036 | * A source location can be found regardless of inlining status for | |
1037 | * this method, but in the case of an inlined function, the returned | |
1038 | * source location will point not to the callsite but rather to the | |
1039 | * definition site of the inline function. | |
1040 | * | |
1041 | * @param cu bt_dwarf_cu instance in which to look for the address | |
1042 | * @param addr The address for which to look for | |
1043 | * @param src_loc Out parameter, the source location (filename and | |
1044 | * line number) for the address | |
1045 | * @returns 0 on success, -1 on failure | |
1046 | */ | |
1047 | static | |
1048 | int so_info_lookup_cu_src_loc_no_inl(struct bt_dwarf_cu *cu, uint64_t addr, | |
1049 | struct source_location **src_loc) | |
1050 | { | |
1051 | struct source_location *_src_loc = NULL; | |
1052 | struct bt_dwarf_die *die = NULL; | |
1053 | const char *filename = NULL; | |
1054 | Dwarf_Line *line = NULL; | |
1055 | Dwarf_Addr line_addr; | |
1056 | int ret, line_no; | |
1057 | ||
1058 | if (!cu || !src_loc) { | |
1059 | goto error; | |
1060 | } | |
1061 | ||
1062 | die = bt_dwarf_die_create(cu); | |
1063 | if (!die) { | |
1064 | goto error; | |
1065 | } | |
1066 | ||
1067 | line = dwarf_getsrc_die(die->dwarf_die, addr); | |
1068 | if (!line) { | |
1069 | goto error; | |
1070 | } | |
1071 | ||
1072 | ret = dwarf_lineaddr(line, &line_addr); | |
1073 | if (ret) { | |
1074 | goto error; | |
1075 | } | |
1076 | ||
1077 | filename = dwarf_linesrc(line, NULL, NULL); | |
1078 | if (!filename) { | |
1079 | goto error; | |
1080 | } | |
1081 | ||
1082 | if (addr == line_addr) { | |
1083 | _src_loc = g_new0(struct source_location, 1); | |
1084 | if (!_src_loc) { | |
1085 | goto error; | |
1086 | } | |
1087 | ||
1088 | ret = dwarf_lineno(line, &line_no); | |
1089 | if (ret) { | |
1090 | goto error; | |
1091 | } | |
1092 | ||
1093 | _src_loc->line_no = line_no; | |
1094 | _src_loc->filename = strdup(filename); | |
1095 | } | |
1096 | ||
1097 | bt_dwarf_die_destroy(die); | |
1098 | ||
1099 | if (_src_loc) { | |
1100 | *src_loc = _src_loc; | |
1101 | } | |
1102 | ||
1103 | return 0; | |
1104 | ||
1105 | error: | |
1106 | source_location_destroy(_src_loc); | |
1107 | bt_dwarf_die_destroy(die); | |
1108 | return -1; | |
1109 | } | |
1110 | ||
1111 | /** | |
1112 | * Get the source location (file name and line number) for a given | |
1113 | * address within a compile unit (CU). | |
1114 | * | |
1115 | * On success, the out parameter `src_loc` is set if found. On | |
1116 | * failure, it remains unchanged. | |
1117 | * | |
1118 | * @param so bt_dwarf_cu instance for the compile unit which | |
1119 | * may contain the address | |
1120 | * @param addr Virtual memory address for which to find the | |
1121 | * source location | |
1122 | * @param src_loc Out parameter, the source location | |
1123 | * @returns 0 on success, -1 on failure | |
1124 | */ | |
1125 | static | |
1126 | int so_info_lookup_cu_src_loc(struct bt_dwarf_cu *cu, uint64_t addr, | |
1127 | struct source_location **src_loc) | |
1128 | { | |
1129 | int ret = 0; | |
1130 | struct source_location *_src_loc = NULL; | |
1131 | ||
1132 | if (!cu || !src_loc) { | |
1133 | goto error; | |
1134 | } | |
1135 | ||
1136 | ret = so_info_lookup_cu_src_loc_inl(cu, addr, &_src_loc); | |
1137 | if (ret) { | |
1138 | goto error; | |
1139 | } | |
1140 | ||
1141 | if (_src_loc) { | |
1142 | goto end; | |
1143 | } | |
1144 | ||
1145 | ret = so_info_lookup_cu_src_loc_no_inl(cu, addr, &_src_loc); | |
1146 | if (ret) { | |
1147 | goto error; | |
1148 | } | |
1149 | ||
1150 | if (_src_loc) { | |
1151 | goto end; | |
1152 | } | |
1153 | ||
1154 | end: | |
1155 | if (_src_loc) { | |
1156 | *src_loc = _src_loc; | |
1157 | } | |
1158 | ||
1159 | return 0; | |
1160 | ||
1161 | error: | |
1162 | source_location_destroy(_src_loc); | |
1163 | return -1; | |
1164 | } | |
1165 | ||
1166 | BT_HIDDEN | |
1167 | int so_info_lookup_source_location(struct so_info *so, uint64_t addr, | |
1168 | struct source_location **src_loc) | |
1169 | { | |
1170 | struct bt_dwarf_cu *cu = NULL; | |
1171 | struct source_location *_src_loc = NULL; | |
1172 | ||
1173 | if (!so || !src_loc) { | |
1174 | goto error; | |
1175 | } | |
1176 | ||
1177 | /* Set DWARF info if it hasn't been accessed yet. */ | |
1178 | if (!so->dwarf_info && !so->is_elf_only) { | |
1179 | if (so_info_set_dwarf_info(so)) { | |
1180 | /* Failed to set DWARF info. */ | |
1181 | so->is_elf_only = true; | |
1182 | } | |
1183 | } | |
1184 | ||
1185 | if (so->is_elf_only) { | |
1186 | /* We cannot lookup source location without DWARF info. */ | |
1187 | goto error; | |
1188 | } | |
1189 | ||
1190 | if (!so_info_has_address(so, addr)) { | |
1191 | goto error; | |
1192 | } | |
1193 | ||
1194 | /* | |
1195 | * Addresses in ELF and DWARF are relative to base address for | |
1196 | * PIC, so make the address argument relative too if needed. | |
1197 | */ | |
1198 | if (so->is_pic) { | |
1199 | addr -= so->low_addr; | |
1200 | } | |
1201 | ||
1202 | cu = bt_dwarf_cu_create(so->dwarf_info); | |
1203 | if (!cu) { | |
1204 | goto error; | |
1205 | } | |
1206 | ||
1207 | while (bt_dwarf_cu_next(cu) == 0) { | |
1208 | int ret; | |
1209 | ||
1210 | ret = so_info_lookup_cu_src_loc(cu, addr, &_src_loc); | |
1211 | if (ret) { | |
1212 | goto error; | |
1213 | } | |
1214 | ||
1215 | if (_src_loc) { | |
1216 | break; | |
1217 | } | |
1218 | } | |
1219 | ||
1220 | bt_dwarf_cu_destroy(cu); | |
1221 | if (_src_loc) { | |
1222 | *src_loc = _src_loc; | |
1223 | } | |
1224 | ||
1225 | return 0; | |
1226 | ||
1227 | error: | |
1228 | source_location_destroy(_src_loc); | |
1229 | bt_dwarf_cu_destroy(cu); | |
1230 | return -1; | |
1231 | } |