Commit | Line | Data |
---|---|---|
8e2aed3f AB |
1 | /* |
2 | * Copyright (C) 2015 Antoine Busque <abusque@efficios.com> | |
3 | * | |
4 | * This library is free software; you can redistribute it and/or | |
5 | * modify it under the terms of the GNU Lesser General Public | |
6 | * License as published by the Free Software Foundation; either | |
7 | * version 2.1 of the License, or (at your option) any later version. | |
8 | * | |
9 | * This library is distributed in the hope that it will be useful, | |
10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
12 | * Lesser General Public License for more details. | |
13 | * | |
14 | * You should have received a copy of the GNU Lesser General Public | |
15 | * License along with this library; if not, write to the Free Software | |
16 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
17 | */ | |
18 | ||
aaf93c60 | 19 | #define _GNU_SOURCE |
8e2aed3f AB |
20 | #include <helper.h> |
21 | #include <string.h> | |
22 | #include <lttng/align.h> | |
23 | #include <lttng/ust-elf.h> | |
405be658 MD |
24 | #include <sys/types.h> |
25 | #include <sys/stat.h> | |
26 | #include <fcntl.h> | |
27 | #include <unistd.h> | |
28 | #include "lttng-tracer-core.h" | |
29 | ||
30 | #define BUF_LEN 4096 | |
8e2aed3f AB |
31 | |
32 | /* | |
33 | * Retrieve the nth (where n is the `index` argument) phdr (program | |
34 | * header) from the given elf instance. | |
35 | * | |
36 | * A pointer to the phdr is returned on success, NULL on failure. | |
37 | */ | |
38 | static | |
39 | struct lttng_ust_elf_phdr *lttng_ust_elf_get_phdr(struct lttng_ust_elf *elf, | |
40 | uint16_t index) | |
41 | { | |
42 | struct lttng_ust_elf_phdr *phdr = NULL; | |
f5a6717a | 43 | off_t offset; |
8e2aed3f AB |
44 | |
45 | if (!elf) { | |
46 | goto error; | |
47 | } | |
48 | ||
49 | if (index >= elf->ehdr->e_phnum) { | |
50 | goto error; | |
51 | } | |
52 | ||
53 | phdr = zmalloc(sizeof(struct lttng_ust_elf_phdr)); | |
54 | if (!phdr) { | |
55 | goto error; | |
56 | } | |
57 | ||
f5a6717a MD |
58 | offset = (off_t) elf->ehdr->e_phoff |
59 | + (off_t) index * elf->ehdr->e_phentsize; | |
405be658 | 60 | if (lseek(elf->fd, offset, SEEK_SET) < 0) { |
8e2aed3f AB |
61 | goto error; |
62 | } | |
63 | ||
64 | if (is_elf_32_bit(elf)) { | |
65 | Elf32_Phdr elf_phdr; | |
66 | ||
405be658 MD |
67 | if (lttng_ust_read(elf->fd, &elf_phdr, sizeof(elf_phdr)) |
68 | < sizeof(elf_phdr)) { | |
8e2aed3f AB |
69 | goto error; |
70 | } | |
71 | if (!is_elf_native_endian(elf)) { | |
72 | bswap_phdr(elf_phdr); | |
73 | } | |
74 | copy_phdr(elf_phdr, *phdr); | |
75 | } else { | |
76 | Elf64_Phdr elf_phdr; | |
77 | ||
405be658 MD |
78 | if (lttng_ust_read(elf->fd, &elf_phdr, sizeof(elf_phdr)) |
79 | < sizeof(elf_phdr)) { | |
8e2aed3f AB |
80 | goto error; |
81 | } | |
82 | if (!is_elf_native_endian(elf)) { | |
83 | bswap_phdr(elf_phdr); | |
84 | } | |
85 | copy_phdr(elf_phdr, *phdr); | |
86 | } | |
87 | ||
88 | return phdr; | |
89 | ||
90 | error: | |
91 | free(phdr); | |
92 | return NULL; | |
93 | } | |
94 | ||
95 | /* | |
96 | * Retrieve the nth (where n is the `index` argument) shdr (section | |
97 | * header) from the given elf instance. | |
98 | * | |
99 | * A pointer to the shdr is returned on success, NULL on failure. | |
100 | */ | |
101 | static | |
102 | struct lttng_ust_elf_shdr *lttng_ust_elf_get_shdr(struct lttng_ust_elf *elf, | |
103 | uint16_t index) | |
104 | { | |
105 | struct lttng_ust_elf_shdr *shdr = NULL; | |
4c5dac0d | 106 | off_t offset; |
8e2aed3f AB |
107 | |
108 | if (!elf) { | |
109 | goto error; | |
110 | } | |
111 | ||
112 | if (index >= elf->ehdr->e_shnum) { | |
113 | goto error; | |
114 | } | |
115 | ||
116 | shdr = zmalloc(sizeof(struct lttng_ust_elf_shdr)); | |
117 | if (!shdr) { | |
118 | goto error; | |
119 | } | |
120 | ||
4c5dac0d | 121 | offset = (off_t) elf->ehdr->e_shoff |
5a26ac54 | 122 | + (off_t) index * elf->ehdr->e_shentsize; |
405be658 | 123 | if (lseek(elf->fd, offset, SEEK_SET) < 0) { |
8e2aed3f AB |
124 | goto error; |
125 | } | |
126 | ||
127 | if (is_elf_32_bit(elf)) { | |
128 | Elf32_Shdr elf_shdr; | |
129 | ||
405be658 MD |
130 | if (lttng_ust_read(elf->fd, &elf_shdr, sizeof(elf_shdr)) |
131 | < sizeof(elf_shdr)) { | |
8e2aed3f AB |
132 | goto error; |
133 | } | |
134 | if (!is_elf_native_endian(elf)) { | |
135 | bswap_shdr(elf_shdr); | |
136 | } | |
137 | copy_shdr(elf_shdr, *shdr); | |
138 | } else { | |
139 | Elf64_Shdr elf_shdr; | |
140 | ||
405be658 MD |
141 | if (lttng_ust_read(elf->fd, &elf_shdr, sizeof(elf_shdr)) |
142 | < sizeof(elf_shdr)) { | |
8e2aed3f AB |
143 | goto error; |
144 | } | |
145 | if (!is_elf_native_endian(elf)) { | |
146 | bswap_shdr(elf_shdr); | |
147 | } | |
148 | copy_shdr(elf_shdr, *shdr); | |
149 | } | |
150 | ||
151 | return shdr; | |
152 | ||
153 | error: | |
154 | free(shdr); | |
155 | return NULL; | |
156 | } | |
157 | ||
158 | /* | |
159 | * Lookup a section's name from a given offset (usually from an shdr's | |
160 | * sh_name value) in bytes relative to the beginning of the section | |
161 | * names string table. | |
162 | * | |
163 | * If no name is found, NULL is returned. | |
164 | */ | |
165 | static | |
f5a6717a | 166 | char *lttng_ust_elf_get_section_name(struct lttng_ust_elf *elf, off_t offset) |
8e2aed3f AB |
167 | { |
168 | char *name = NULL; | |
405be658 | 169 | size_t len = 0, to_read; /* len does not include \0 */ |
8e2aed3f AB |
170 | |
171 | if (!elf) { | |
172 | goto error; | |
173 | } | |
174 | ||
175 | if (offset >= elf->section_names_size) { | |
176 | goto error; | |
177 | } | |
178 | ||
405be658 | 179 | if (lseek(elf->fd, elf->section_names_offset + offset, SEEK_SET) < 0) { |
8e2aed3f AB |
180 | goto error; |
181 | } | |
405be658 MD |
182 | |
183 | to_read = elf->section_names_size - offset; | |
184 | ||
185 | /* Find first \0 after or at current location, remember len. */ | |
186 | for (;;) { | |
187 | char buf[BUF_LEN]; | |
188 | ssize_t read_len; | |
189 | size_t i; | |
190 | ||
191 | if (!to_read) { | |
8e2aed3f | 192 | goto error; |
8e2aed3f | 193 | } |
405be658 MD |
194 | read_len = lttng_ust_read(elf->fd, buf, |
195 | min_t(size_t, BUF_LEN, to_read)); | |
196 | if (read_len <= 0) { | |
197 | goto error; | |
198 | } | |
199 | for (i = 0; i < read_len; i++) { | |
200 | if (buf[i] == '\0') { | |
201 | len += i; | |
202 | goto end; | |
203 | } | |
204 | } | |
205 | len += read_len; | |
206 | to_read -= read_len; | |
8e2aed3f | 207 | } |
8e2aed3f | 208 | end: |
405be658 | 209 | name = zmalloc(sizeof(char) * (len + 1)); /* + 1 for \0 */ |
8e2aed3f AB |
210 | if (!name) { |
211 | goto error; | |
212 | } | |
405be658 MD |
213 | if (lseek(elf->fd, elf->section_names_offset + offset, |
214 | SEEK_SET) < 0) { | |
8e2aed3f AB |
215 | goto error; |
216 | } | |
405be658 | 217 | if (lttng_ust_read(elf->fd, name, len + 1) < len + 1) { |
8e2aed3f AB |
218 | goto error; |
219 | } | |
220 | ||
221 | return name; | |
222 | ||
223 | error: | |
224 | free(name); | |
225 | return NULL; | |
226 | } | |
227 | ||
228 | /* | |
229 | * Create an instance of lttng_ust_elf for the ELF file located at | |
230 | * `path`. | |
231 | * | |
232 | * Return a pointer to the instance on success, NULL on failure. | |
233 | */ | |
234 | struct lttng_ust_elf *lttng_ust_elf_create(const char *path) | |
235 | { | |
236 | uint8_t e_ident[EI_NIDENT]; | |
237 | struct lttng_ust_elf_shdr *section_names_shdr; | |
405be658 | 238 | struct lttng_ust_elf *elf = NULL; |
8e2aed3f AB |
239 | |
240 | elf = zmalloc(sizeof(struct lttng_ust_elf)); | |
241 | if (!elf) { | |
242 | goto error; | |
243 | } | |
244 | ||
245 | elf->path = strdup(path); | |
246 | if (!elf->path) { | |
247 | goto error; | |
248 | } | |
249 | ||
405be658 MD |
250 | elf->fd = open(elf->path, O_RDONLY | O_CLOEXEC); |
251 | if (elf->fd < 0) { | |
8e2aed3f AB |
252 | goto error; |
253 | } | |
254 | ||
405be658 | 255 | if (lttng_ust_read(elf->fd, e_ident, EI_NIDENT) < EI_NIDENT) { |
8e2aed3f AB |
256 | goto error; |
257 | } | |
258 | elf->bitness = e_ident[EI_CLASS]; | |
259 | elf->endianness = e_ident[EI_DATA]; | |
405be658 MD |
260 | |
261 | if (lseek(elf->fd, 0, SEEK_SET) < 0) { | |
262 | goto error; | |
263 | } | |
8e2aed3f AB |
264 | |
265 | elf->ehdr = zmalloc(sizeof(struct lttng_ust_elf_ehdr)); | |
266 | if (!elf->ehdr) { | |
267 | goto error; | |
268 | } | |
269 | ||
270 | if (is_elf_32_bit(elf)) { | |
271 | Elf32_Ehdr elf_ehdr; | |
272 | ||
405be658 MD |
273 | if (lttng_ust_read(elf->fd, &elf_ehdr, sizeof(elf_ehdr)) |
274 | < sizeof(elf_ehdr)) { | |
8e2aed3f AB |
275 | goto error; |
276 | } | |
277 | if (!is_elf_native_endian(elf)) { | |
278 | bswap_ehdr(elf_ehdr); | |
279 | } | |
280 | copy_ehdr(elf_ehdr, *(elf->ehdr)); | |
281 | } else { | |
282 | Elf64_Ehdr elf_ehdr; | |
283 | ||
405be658 MD |
284 | if (lttng_ust_read(elf->fd, &elf_ehdr, sizeof(elf_ehdr)) |
285 | < sizeof(elf_ehdr)) { | |
8e2aed3f AB |
286 | goto error; |
287 | } | |
288 | if (!is_elf_native_endian(elf)) { | |
289 | bswap_ehdr(elf_ehdr); | |
290 | } | |
291 | copy_ehdr(elf_ehdr, *(elf->ehdr)); | |
292 | } | |
293 | ||
294 | section_names_shdr = lttng_ust_elf_get_shdr(elf, elf->ehdr->e_shstrndx); | |
295 | if (!section_names_shdr) { | |
296 | goto error; | |
297 | } | |
298 | ||
299 | elf->section_names_offset = section_names_shdr->sh_offset; | |
300 | elf->section_names_size = section_names_shdr->sh_size; | |
301 | ||
302 | free(section_names_shdr); | |
8e2aed3f AB |
303 | return elf; |
304 | ||
305 | error: | |
306 | if (elf) { | |
307 | free(elf->ehdr); | |
405be658 MD |
308 | if (elf->fd >= 0) { |
309 | if (close(elf->fd)) { | |
310 | abort(); | |
311 | } | |
312 | } | |
8e2aed3f | 313 | free(elf->path); |
405be658 | 314 | free(elf); |
8e2aed3f | 315 | } |
8e2aed3f AB |
316 | return NULL; |
317 | } | |
318 | ||
f5eb039d AB |
319 | /* |
320 | * Test whether the ELF file is position independent code (PIC) | |
321 | */ | |
322 | uint8_t lttng_ust_elf_is_pic(struct lttng_ust_elf *elf) | |
323 | { | |
324 | /* | |
325 | * PIC has and e_type value of ET_DYN, see ELF specification | |
326 | * version 1.1 p. 1-3. | |
327 | */ | |
328 | return elf->ehdr->e_type == ET_DYN; | |
329 | } | |
330 | ||
8e2aed3f AB |
331 | /* |
332 | * Destroy the given lttng_ust_elf instance. | |
333 | */ | |
334 | void lttng_ust_elf_destroy(struct lttng_ust_elf *elf) | |
335 | { | |
336 | if (!elf) { | |
337 | return; | |
338 | } | |
339 | ||
340 | free(elf->ehdr); | |
405be658 MD |
341 | if (close(elf->fd)) { |
342 | abort(); | |
343 | } | |
8e2aed3f AB |
344 | free(elf->path); |
345 | free(elf); | |
346 | } | |
347 | ||
348 | /* | |
349 | * Compute the total in-memory size of the ELF file, in bytes. | |
350 | * | |
351 | * Returns 0 if successful, -1 if not. On success, the memory size is | |
352 | * returned through the out parameter `memsz`. | |
353 | */ | |
354 | int lttng_ust_elf_get_memsz(struct lttng_ust_elf *elf, uint64_t *memsz) | |
355 | { | |
356 | uint16_t i; | |
357 | uint64_t _memsz = 0; | |
358 | ||
359 | if (!elf || !memsz) { | |
360 | goto error; | |
361 | } | |
362 | ||
363 | for (i = 0; i < elf->ehdr->e_phnum; ++i) { | |
364 | struct lttng_ust_elf_phdr *phdr; | |
365 | uint64_t align; | |
366 | ||
367 | phdr = lttng_ust_elf_get_phdr(elf, i); | |
368 | if (!phdr) { | |
369 | goto error; | |
370 | } | |
371 | ||
372 | /* | |
373 | * Only PT_LOAD segments contribute to memsz. Skip | |
374 | * other segments. | |
375 | */ | |
376 | if (phdr->p_type != PT_LOAD) { | |
377 | goto next_loop; | |
378 | } | |
379 | ||
380 | /* | |
381 | * A p_align of 0 means no alignment, i.e. aligned to | |
382 | * 1 byte. | |
383 | */ | |
384 | align = phdr->p_align == 0 ? 1 : phdr->p_align; | |
385 | /* Align the start of the segment. */ | |
386 | _memsz += offset_align(_memsz, align); | |
387 | _memsz += phdr->p_memsz; | |
388 | /* | |
389 | * Add padding at the end of the segment, so it ends | |
390 | * on a multiple of the align value (which usually | |
391 | * means a page boundary). This makes the computation | |
392 | * valid even in cases where p_align would change from | |
393 | * one segment to the next. | |
394 | */ | |
395 | _memsz += offset_align(_memsz, align); | |
396 | next_loop: | |
397 | free(phdr); | |
398 | } | |
399 | ||
400 | *memsz = _memsz; | |
401 | return 0; | |
402 | error: | |
403 | return -1; | |
404 | } | |
405 | ||
406 | /* | |
407 | * Internal method used to try and get the build_id from a PT_NOTE | |
408 | * segment ranging from `offset` to `segment_end`. | |
409 | * | |
410 | * If the function returns successfully, the out parameter `found` | |
411 | * indicates whether the build id information was present in the | |
412 | * segment or not. If `found` is not 0, the out parameters `build_id` | |
413 | * and `length` will both have been set with the retrieved | |
414 | * information. | |
415 | * | |
416 | * Returns 0 on success, -1 if an error occurred. | |
417 | */ | |
418 | static | |
419 | int lttng_ust_elf_get_build_id_from_segment( | |
420 | struct lttng_ust_elf *elf, uint8_t **build_id, size_t *length, | |
82ee1ee4 | 421 | off_t offset, off_t segment_end) |
8e2aed3f | 422 | { |
814d07b1 MD |
423 | uint8_t *_build_id = NULL; /* Silence old gcc warning. */ |
424 | size_t _length = 0; /* Silence old gcc warning. */ | |
8e2aed3f AB |
425 | |
426 | while (offset < segment_end) { | |
427 | struct lttng_ust_elf_nhdr nhdr; | |
405be658 | 428 | size_t read_len; |
8e2aed3f AB |
429 | |
430 | /* Align start of note entry */ | |
431 | offset += offset_align(offset, ELF_NOTE_ENTRY_ALIGN); | |
432 | if (offset >= segment_end) { | |
433 | break; | |
434 | } | |
435 | /* | |
436 | * We seek manually because if the note isn't the | |
437 | * build id the data following the header will not | |
438 | * have been read. | |
439 | */ | |
405be658 | 440 | if (lseek(elf->fd, offset, SEEK_SET) < 0) { |
8e2aed3f AB |
441 | goto error; |
442 | } | |
405be658 MD |
443 | if (lttng_ust_read(elf->fd, &nhdr, sizeof(nhdr)) |
444 | < sizeof(nhdr)) { | |
8e2aed3f AB |
445 | goto error; |
446 | } | |
447 | ||
448 | if (!is_elf_native_endian(elf)) { | |
449 | nhdr.n_namesz = bswap_32(nhdr.n_namesz); | |
450 | nhdr.n_descsz = bswap_32(nhdr.n_descsz); | |
451 | nhdr.n_type = bswap_32(nhdr.n_type); | |
452 | } | |
453 | ||
454 | offset += sizeof(nhdr) + nhdr.n_namesz; | |
455 | /* Align start of desc entry */ | |
456 | offset += offset_align(offset, ELF_NOTE_DESC_ALIGN); | |
457 | ||
458 | if (nhdr.n_type != NT_GNU_BUILD_ID) { | |
459 | /* | |
460 | * Ignore non build id notes but still | |
461 | * increase the offset. | |
462 | */ | |
463 | offset += nhdr.n_descsz; | |
464 | continue; | |
465 | } | |
466 | ||
467 | _length = nhdr.n_descsz; | |
468 | _build_id = zmalloc(sizeof(uint8_t) * _length); | |
5ada26b4 | 469 | if (!_build_id) { |
8e2aed3f AB |
470 | goto error; |
471 | } | |
472 | ||
405be658 | 473 | if (lseek(elf->fd, offset, SEEK_SET) < 0) { |
8e2aed3f AB |
474 | goto error; |
475 | } | |
405be658 MD |
476 | read_len = sizeof(*_build_id) * _length; |
477 | if (lttng_ust_read(elf->fd, _build_id, read_len) < read_len) { | |
8e2aed3f AB |
478 | goto error; |
479 | } | |
480 | ||
8e2aed3f AB |
481 | break; |
482 | } | |
483 | ||
82ee1ee4 | 484 | if (_build_id) { |
8e2aed3f AB |
485 | *build_id = _build_id; |
486 | *length = _length; | |
487 | } | |
488 | ||
8e2aed3f AB |
489 | return 0; |
490 | error: | |
83215d66 | 491 | free(_build_id); |
8e2aed3f AB |
492 | return -1; |
493 | } | |
494 | ||
495 | /* | |
496 | * Retrieve a build ID (an array of bytes) from the corresponding | |
497 | * section in the ELF file. The length of the build ID can be either | |
498 | * 16 or 20 bytes depending on the method used to generate it, hence | |
499 | * the length out parameter. | |
500 | * | |
501 | * If the function returns successfully, the out parameter `found` | |
502 | * indicates whether the build id information was present in the ELF | |
503 | * file or not. If `found` is not 0, the out parameters `build_id` and | |
504 | * `length` will both have been set with the retrieved information. | |
505 | * | |
506 | * Returns 0 on success, -1 if an error occurred. | |
507 | */ | |
508 | int lttng_ust_elf_get_build_id(struct lttng_ust_elf *elf, uint8_t **build_id, | |
509 | size_t *length, int *found) | |
510 | { | |
511 | uint16_t i; | |
8c83dbda MD |
512 | uint8_t *_build_id = NULL; /* Silence old gcc warning. */ |
513 | size_t _length = 0; /* Silence old gcc warning. */ | |
8e2aed3f AB |
514 | |
515 | if (!elf || !build_id || !length || !found) { | |
516 | goto error; | |
517 | } | |
518 | ||
519 | for (i = 0; i < elf->ehdr->e_phnum; ++i) { | |
f5a6717a | 520 | off_t offset, segment_end; |
8e2aed3f | 521 | struct lttng_ust_elf_phdr *phdr; |
5b3bbf98 | 522 | int ret = 0; |
8e2aed3f AB |
523 | |
524 | phdr = lttng_ust_elf_get_phdr(elf, i); | |
525 | if (!phdr) { | |
526 | goto error; | |
527 | } | |
528 | ||
529 | /* Build ID will be contained in a PT_NOTE segment. */ | |
530 | if (phdr->p_type != PT_NOTE) { | |
531 | goto next_loop; | |
532 | } | |
533 | ||
534 | offset = phdr->p_offset; | |
535 | segment_end = offset + phdr->p_filesz; | |
536 | ret = lttng_ust_elf_get_build_id_from_segment( | |
82ee1ee4 | 537 | elf, &_build_id, &_length, offset, segment_end); |
8e2aed3f AB |
538 | next_loop: |
539 | free(phdr); | |
540 | if (ret) { | |
541 | goto error; | |
542 | } | |
82ee1ee4 | 543 | if (_build_id) { |
8e2aed3f AB |
544 | break; |
545 | } | |
546 | } | |
547 | ||
82ee1ee4 | 548 | if (_build_id) { |
8e2aed3f AB |
549 | *build_id = _build_id; |
550 | *length = _length; | |
82ee1ee4 AB |
551 | *found = 1; |
552 | } else { | |
553 | *found = 0; | |
8e2aed3f AB |
554 | } |
555 | ||
8e2aed3f AB |
556 | return 0; |
557 | error: | |
99b7132d | 558 | free(_build_id); |
8e2aed3f AB |
559 | return -1; |
560 | } | |
561 | ||
562 | /* | |
563 | * Try to retrieve filename and CRC from given ELF section `shdr`. | |
564 | * | |
565 | * If the function returns successfully, the out parameter `found` | |
566 | * indicates whether the debug link information was present in the ELF | |
567 | * section or not. If `found` is not 0, the out parameters `filename` and | |
568 | * `crc` will both have been set with the retrieved information. | |
569 | * | |
570 | * Returns 0 on success, -1 if an error occurred. | |
571 | */ | |
8e2aed3f AB |
572 | int lttng_ust_elf_get_debug_link_from_section(struct lttng_ust_elf *elf, |
573 | char **filename, uint32_t *crc, | |
8e2aed3f AB |
574 | struct lttng_ust_elf_shdr *shdr) |
575 | { | |
8c83dbda | 576 | char *_filename = NULL; /* Silence old gcc warning. */ |
405be658 | 577 | size_t filename_len; |
8e2aed3f | 578 | char *section_name = NULL; |
8c83dbda | 579 | uint32_t _crc = 0; /* Silence old gcc warning. */ |
8e2aed3f | 580 | |
82ee1ee4 | 581 | if (!elf || !filename || !crc || !shdr) { |
8e2aed3f AB |
582 | goto error; |
583 | } | |
584 | ||
585 | /* | |
586 | * The .gnu_debuglink section is of type SHT_PROGBITS, | |
587 | * skip the other sections. | |
588 | */ | |
589 | if (shdr->sh_type != SHT_PROGBITS) { | |
590 | goto end; | |
591 | } | |
592 | ||
593 | section_name = lttng_ust_elf_get_section_name(elf, | |
594 | shdr->sh_name); | |
595 | if (!section_name) { | |
596 | goto end; | |
597 | } | |
598 | if (strcmp(section_name, ".gnu_debuglink")) { | |
599 | goto end; | |
600 | } | |
601 | ||
602 | /* | |
603 | * The length of the filename is the sh_size excluding the CRC | |
604 | * which comes after it in the section. | |
605 | */ | |
606 | _filename = zmalloc(sizeof(char) * (shdr->sh_size - ELF_CRC_SIZE)); | |
607 | if (!_filename) { | |
608 | goto error; | |
609 | } | |
405be658 | 610 | if (lseek(elf->fd, shdr->sh_offset, SEEK_SET) < 0) { |
8e2aed3f AB |
611 | goto error; |
612 | } | |
405be658 MD |
613 | filename_len = sizeof(*_filename) * (shdr->sh_size - ELF_CRC_SIZE); |
614 | if (lttng_ust_read(elf->fd, _filename, filename_len) < filename_len) { | |
8e2aed3f AB |
615 | goto error; |
616 | } | |
405be658 | 617 | if (lttng_ust_read(elf->fd, &_crc, sizeof(_crc)) < sizeof(_crc)) { |
8e2aed3f AB |
618 | goto error; |
619 | } | |
620 | if (!is_elf_native_endian(elf)) { | |
621 | _crc = bswap_32(_crc); | |
622 | } | |
623 | ||
8e2aed3f AB |
624 | end: |
625 | free(section_name); | |
82ee1ee4 | 626 | if (_filename) { |
8e2aed3f AB |
627 | *filename = _filename; |
628 | *crc = _crc; | |
629 | } | |
8e2aed3f AB |
630 | |
631 | return 0; | |
632 | ||
633 | error: | |
83215d66 MD |
634 | free(_filename); |
635 | free(section_name); | |
8e2aed3f AB |
636 | return -1; |
637 | } | |
638 | ||
639 | /* | |
640 | * Retrieve filename and CRC from ELF's .gnu_debuglink section, if any. | |
641 | * | |
642 | * If the function returns successfully, the out parameter `found` | |
643 | * indicates whether the debug link information was present in the ELF | |
644 | * file or not. If `found` is not 0, the out parameters `filename` and | |
645 | * `crc` will both have been set with the retrieved information. | |
646 | * | |
647 | * Returns 0 on success, -1 if an error occurred. | |
648 | */ | |
649 | int lttng_ust_elf_get_debug_link(struct lttng_ust_elf *elf, char **filename, | |
650 | uint32_t *crc, int *found) | |
651 | { | |
652 | int ret; | |
653 | uint16_t i; | |
8c83dbda MD |
654 | char *_filename = NULL; /* Silence old gcc warning. */ |
655 | uint32_t _crc = 0; /* Silence old gcc warning. */ | |
8e2aed3f AB |
656 | |
657 | if (!elf || !filename || !crc || !found) { | |
658 | goto error; | |
659 | } | |
660 | ||
661 | for (i = 0; i < elf->ehdr->e_shnum; ++i) { | |
662 | struct lttng_ust_elf_shdr *shdr = NULL; | |
663 | ||
664 | shdr = lttng_ust_elf_get_shdr(elf, i); | |
665 | if (!shdr) { | |
666 | goto error; | |
667 | } | |
668 | ||
669 | ret = lttng_ust_elf_get_debug_link_from_section( | |
82ee1ee4 | 670 | elf, &_filename, &_crc, shdr); |
8e2aed3f AB |
671 | free(shdr); |
672 | ||
673 | if (ret) { | |
674 | goto error; | |
675 | } | |
82ee1ee4 | 676 | if (_filename) { |
8e2aed3f AB |
677 | break; |
678 | } | |
679 | } | |
680 | ||
82ee1ee4 | 681 | if (_filename) { |
8e2aed3f AB |
682 | *filename = _filename; |
683 | *crc = _crc; | |
82ee1ee4 AB |
684 | *found = 1; |
685 | } else { | |
686 | *found = 0; | |
8e2aed3f AB |
687 | } |
688 | ||
8e2aed3f | 689 | return 0; |
82ee1ee4 | 690 | |
8e2aed3f | 691 | error: |
99b7132d | 692 | free(_filename); |
8e2aed3f AB |
693 | return -1; |
694 | } |