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 | 31 | |
ac319069 PP |
32 | #ifndef NT_GNU_BUILD_ID |
33 | # define NT_GNU_BUILD_ID 3 | |
34 | #endif | |
35 | ||
8e2aed3f AB |
36 | /* |
37 | * Retrieve the nth (where n is the `index` argument) phdr (program | |
38 | * header) from the given elf instance. | |
39 | * | |
40 | * A pointer to the phdr is returned on success, NULL on failure. | |
41 | */ | |
42 | static | |
43 | struct lttng_ust_elf_phdr *lttng_ust_elf_get_phdr(struct lttng_ust_elf *elf, | |
44 | uint16_t index) | |
45 | { | |
46 | struct lttng_ust_elf_phdr *phdr = NULL; | |
f5a6717a | 47 | off_t offset; |
8e2aed3f AB |
48 | |
49 | if (!elf) { | |
50 | goto error; | |
51 | } | |
52 | ||
53 | if (index >= elf->ehdr->e_phnum) { | |
54 | goto error; | |
55 | } | |
56 | ||
57 | phdr = zmalloc(sizeof(struct lttng_ust_elf_phdr)); | |
58 | if (!phdr) { | |
59 | goto error; | |
60 | } | |
61 | ||
f5a6717a MD |
62 | offset = (off_t) elf->ehdr->e_phoff |
63 | + (off_t) index * elf->ehdr->e_phentsize; | |
405be658 | 64 | if (lseek(elf->fd, offset, SEEK_SET) < 0) { |
8e2aed3f AB |
65 | goto error; |
66 | } | |
67 | ||
68 | if (is_elf_32_bit(elf)) { | |
69 | Elf32_Phdr elf_phdr; | |
70 | ||
405be658 MD |
71 | if (lttng_ust_read(elf->fd, &elf_phdr, sizeof(elf_phdr)) |
72 | < sizeof(elf_phdr)) { | |
8e2aed3f AB |
73 | goto error; |
74 | } | |
75 | if (!is_elf_native_endian(elf)) { | |
76 | bswap_phdr(elf_phdr); | |
77 | } | |
78 | copy_phdr(elf_phdr, *phdr); | |
79 | } else { | |
80 | Elf64_Phdr elf_phdr; | |
81 | ||
405be658 MD |
82 | if (lttng_ust_read(elf->fd, &elf_phdr, sizeof(elf_phdr)) |
83 | < sizeof(elf_phdr)) { | |
8e2aed3f AB |
84 | goto error; |
85 | } | |
86 | if (!is_elf_native_endian(elf)) { | |
87 | bswap_phdr(elf_phdr); | |
88 | } | |
89 | copy_phdr(elf_phdr, *phdr); | |
90 | } | |
91 | ||
92 | return phdr; | |
93 | ||
94 | error: | |
95 | free(phdr); | |
96 | return NULL; | |
97 | } | |
98 | ||
99 | /* | |
100 | * Retrieve the nth (where n is the `index` argument) shdr (section | |
101 | * header) from the given elf instance. | |
102 | * | |
103 | * A pointer to the shdr is returned on success, NULL on failure. | |
104 | */ | |
105 | static | |
106 | struct lttng_ust_elf_shdr *lttng_ust_elf_get_shdr(struct lttng_ust_elf *elf, | |
107 | uint16_t index) | |
108 | { | |
109 | struct lttng_ust_elf_shdr *shdr = NULL; | |
4c5dac0d | 110 | off_t offset; |
8e2aed3f AB |
111 | |
112 | if (!elf) { | |
113 | goto error; | |
114 | } | |
115 | ||
116 | if (index >= elf->ehdr->e_shnum) { | |
117 | goto error; | |
118 | } | |
119 | ||
120 | shdr = zmalloc(sizeof(struct lttng_ust_elf_shdr)); | |
121 | if (!shdr) { | |
122 | goto error; | |
123 | } | |
124 | ||
4c5dac0d | 125 | offset = (off_t) elf->ehdr->e_shoff |
5a26ac54 | 126 | + (off_t) index * elf->ehdr->e_shentsize; |
405be658 | 127 | if (lseek(elf->fd, offset, SEEK_SET) < 0) { |
8e2aed3f AB |
128 | goto error; |
129 | } | |
130 | ||
131 | if (is_elf_32_bit(elf)) { | |
132 | Elf32_Shdr elf_shdr; | |
133 | ||
405be658 MD |
134 | if (lttng_ust_read(elf->fd, &elf_shdr, sizeof(elf_shdr)) |
135 | < sizeof(elf_shdr)) { | |
8e2aed3f AB |
136 | goto error; |
137 | } | |
138 | if (!is_elf_native_endian(elf)) { | |
139 | bswap_shdr(elf_shdr); | |
140 | } | |
141 | copy_shdr(elf_shdr, *shdr); | |
142 | } else { | |
143 | Elf64_Shdr elf_shdr; | |
144 | ||
405be658 MD |
145 | if (lttng_ust_read(elf->fd, &elf_shdr, sizeof(elf_shdr)) |
146 | < sizeof(elf_shdr)) { | |
8e2aed3f AB |
147 | goto error; |
148 | } | |
149 | if (!is_elf_native_endian(elf)) { | |
150 | bswap_shdr(elf_shdr); | |
151 | } | |
152 | copy_shdr(elf_shdr, *shdr); | |
153 | } | |
154 | ||
155 | return shdr; | |
156 | ||
157 | error: | |
158 | free(shdr); | |
159 | return NULL; | |
160 | } | |
161 | ||
162 | /* | |
163 | * Lookup a section's name from a given offset (usually from an shdr's | |
164 | * sh_name value) in bytes relative to the beginning of the section | |
165 | * names string table. | |
166 | * | |
167 | * If no name is found, NULL is returned. | |
168 | */ | |
169 | static | |
f5a6717a | 170 | char *lttng_ust_elf_get_section_name(struct lttng_ust_elf *elf, off_t offset) |
8e2aed3f AB |
171 | { |
172 | char *name = NULL; | |
405be658 | 173 | size_t len = 0, to_read; /* len does not include \0 */ |
8e2aed3f AB |
174 | |
175 | if (!elf) { | |
176 | goto error; | |
177 | } | |
178 | ||
179 | if (offset >= elf->section_names_size) { | |
180 | goto error; | |
181 | } | |
182 | ||
405be658 | 183 | if (lseek(elf->fd, elf->section_names_offset + offset, SEEK_SET) < 0) { |
8e2aed3f AB |
184 | goto error; |
185 | } | |
405be658 MD |
186 | |
187 | to_read = elf->section_names_size - offset; | |
188 | ||
189 | /* Find first \0 after or at current location, remember len. */ | |
190 | for (;;) { | |
191 | char buf[BUF_LEN]; | |
192 | ssize_t read_len; | |
193 | size_t i; | |
194 | ||
195 | if (!to_read) { | |
8e2aed3f | 196 | goto error; |
8e2aed3f | 197 | } |
405be658 MD |
198 | read_len = lttng_ust_read(elf->fd, buf, |
199 | min_t(size_t, BUF_LEN, to_read)); | |
200 | if (read_len <= 0) { | |
201 | goto error; | |
202 | } | |
203 | for (i = 0; i < read_len; i++) { | |
204 | if (buf[i] == '\0') { | |
205 | len += i; | |
206 | goto end; | |
207 | } | |
208 | } | |
209 | len += read_len; | |
210 | to_read -= read_len; | |
8e2aed3f | 211 | } |
8e2aed3f | 212 | end: |
405be658 | 213 | name = zmalloc(sizeof(char) * (len + 1)); /* + 1 for \0 */ |
8e2aed3f AB |
214 | if (!name) { |
215 | goto error; | |
216 | } | |
405be658 MD |
217 | if (lseek(elf->fd, elf->section_names_offset + offset, |
218 | SEEK_SET) < 0) { | |
8e2aed3f AB |
219 | goto error; |
220 | } | |
405be658 | 221 | if (lttng_ust_read(elf->fd, name, len + 1) < len + 1) { |
8e2aed3f AB |
222 | goto error; |
223 | } | |
224 | ||
225 | return name; | |
226 | ||
227 | error: | |
228 | free(name); | |
229 | return NULL; | |
230 | } | |
231 | ||
232 | /* | |
233 | * Create an instance of lttng_ust_elf for the ELF file located at | |
234 | * `path`. | |
235 | * | |
236 | * Return a pointer to the instance on success, NULL on failure. | |
237 | */ | |
238 | struct lttng_ust_elf *lttng_ust_elf_create(const char *path) | |
239 | { | |
240 | uint8_t e_ident[EI_NIDENT]; | |
241 | struct lttng_ust_elf_shdr *section_names_shdr; | |
405be658 | 242 | struct lttng_ust_elf *elf = NULL; |
8e2aed3f AB |
243 | |
244 | elf = zmalloc(sizeof(struct lttng_ust_elf)); | |
245 | if (!elf) { | |
246 | goto error; | |
247 | } | |
248 | ||
249 | elf->path = strdup(path); | |
250 | if (!elf->path) { | |
251 | goto error; | |
252 | } | |
253 | ||
405be658 MD |
254 | elf->fd = open(elf->path, O_RDONLY | O_CLOEXEC); |
255 | if (elf->fd < 0) { | |
8e2aed3f AB |
256 | goto error; |
257 | } | |
258 | ||
405be658 | 259 | if (lttng_ust_read(elf->fd, e_ident, EI_NIDENT) < EI_NIDENT) { |
8e2aed3f AB |
260 | goto error; |
261 | } | |
262 | elf->bitness = e_ident[EI_CLASS]; | |
263 | elf->endianness = e_ident[EI_DATA]; | |
405be658 MD |
264 | |
265 | if (lseek(elf->fd, 0, SEEK_SET) < 0) { | |
266 | goto error; | |
267 | } | |
8e2aed3f AB |
268 | |
269 | elf->ehdr = zmalloc(sizeof(struct lttng_ust_elf_ehdr)); | |
270 | if (!elf->ehdr) { | |
271 | goto error; | |
272 | } | |
273 | ||
274 | if (is_elf_32_bit(elf)) { | |
275 | Elf32_Ehdr elf_ehdr; | |
276 | ||
405be658 MD |
277 | if (lttng_ust_read(elf->fd, &elf_ehdr, sizeof(elf_ehdr)) |
278 | < sizeof(elf_ehdr)) { | |
8e2aed3f AB |
279 | goto error; |
280 | } | |
281 | if (!is_elf_native_endian(elf)) { | |
282 | bswap_ehdr(elf_ehdr); | |
283 | } | |
284 | copy_ehdr(elf_ehdr, *(elf->ehdr)); | |
285 | } else { | |
286 | Elf64_Ehdr elf_ehdr; | |
287 | ||
405be658 MD |
288 | if (lttng_ust_read(elf->fd, &elf_ehdr, sizeof(elf_ehdr)) |
289 | < sizeof(elf_ehdr)) { | |
8e2aed3f AB |
290 | goto error; |
291 | } | |
292 | if (!is_elf_native_endian(elf)) { | |
293 | bswap_ehdr(elf_ehdr); | |
294 | } | |
295 | copy_ehdr(elf_ehdr, *(elf->ehdr)); | |
296 | } | |
297 | ||
298 | section_names_shdr = lttng_ust_elf_get_shdr(elf, elf->ehdr->e_shstrndx); | |
299 | if (!section_names_shdr) { | |
300 | goto error; | |
301 | } | |
302 | ||
303 | elf->section_names_offset = section_names_shdr->sh_offset; | |
304 | elf->section_names_size = section_names_shdr->sh_size; | |
305 | ||
306 | free(section_names_shdr); | |
8e2aed3f AB |
307 | return elf; |
308 | ||
309 | error: | |
310 | if (elf) { | |
311 | free(elf->ehdr); | |
405be658 MD |
312 | if (elf->fd >= 0) { |
313 | if (close(elf->fd)) { | |
314 | abort(); | |
315 | } | |
316 | } | |
8e2aed3f | 317 | free(elf->path); |
405be658 | 318 | free(elf); |
8e2aed3f | 319 | } |
8e2aed3f AB |
320 | return NULL; |
321 | } | |
322 | ||
444da810 AB |
323 | /* |
324 | * Test whether the ELF file is position independent code (PIC) | |
325 | */ | |
326 | uint8_t lttng_ust_elf_is_pic(struct lttng_ust_elf *elf) | |
327 | { | |
328 | /* | |
329 | * PIC has and e_type value of ET_DYN, see ELF specification | |
330 | * version 1.1 p. 1-3. | |
331 | */ | |
332 | return elf->ehdr->e_type == ET_DYN; | |
333 | } | |
334 | ||
8e2aed3f AB |
335 | /* |
336 | * Destroy the given lttng_ust_elf instance. | |
337 | */ | |
338 | void lttng_ust_elf_destroy(struct lttng_ust_elf *elf) | |
339 | { | |
340 | if (!elf) { | |
341 | return; | |
342 | } | |
343 | ||
344 | free(elf->ehdr); | |
405be658 MD |
345 | if (close(elf->fd)) { |
346 | abort(); | |
347 | } | |
8e2aed3f AB |
348 | free(elf->path); |
349 | free(elf); | |
350 | } | |
351 | ||
352 | /* | |
353 | * Compute the total in-memory size of the ELF file, in bytes. | |
354 | * | |
355 | * Returns 0 if successful, -1 if not. On success, the memory size is | |
356 | * returned through the out parameter `memsz`. | |
357 | */ | |
358 | int lttng_ust_elf_get_memsz(struct lttng_ust_elf *elf, uint64_t *memsz) | |
359 | { | |
360 | uint16_t i; | |
68d4b11c | 361 | uint64_t low_addr = UINT64_MAX, high_addr = 0; |
8e2aed3f AB |
362 | |
363 | if (!elf || !memsz) { | |
364 | goto error; | |
365 | } | |
366 | ||
367 | for (i = 0; i < elf->ehdr->e_phnum; ++i) { | |
368 | struct lttng_ust_elf_phdr *phdr; | |
8e2aed3f AB |
369 | |
370 | phdr = lttng_ust_elf_get_phdr(elf, i); | |
371 | if (!phdr) { | |
372 | goto error; | |
373 | } | |
374 | ||
375 | /* | |
376 | * Only PT_LOAD segments contribute to memsz. Skip | |
377 | * other segments. | |
378 | */ | |
379 | if (phdr->p_type != PT_LOAD) { | |
380 | goto next_loop; | |
381 | } | |
382 | ||
8620f426 MD |
383 | low_addr = min_t(uint64_t, low_addr, phdr->p_vaddr); |
384 | high_addr = max_t(uint64_t, high_addr, | |
385 | phdr->p_vaddr + phdr->p_memsz); | |
8e2aed3f AB |
386 | next_loop: |
387 | free(phdr); | |
388 | } | |
389 | ||
68d4b11c AB |
390 | if (high_addr < low_addr) { |
391 | /* No PT_LOAD segments or corrupted data. */ | |
392 | goto error; | |
393 | } | |
394 | ||
395 | *memsz = high_addr - low_addr; | |
8e2aed3f AB |
396 | return 0; |
397 | error: | |
398 | return -1; | |
399 | } | |
400 | ||
401 | /* | |
402 | * Internal method used to try and get the build_id from a PT_NOTE | |
403 | * segment ranging from `offset` to `segment_end`. | |
404 | * | |
405 | * If the function returns successfully, the out parameter `found` | |
406 | * indicates whether the build id information was present in the | |
407 | * segment or not. If `found` is not 0, the out parameters `build_id` | |
408 | * and `length` will both have been set with the retrieved | |
409 | * information. | |
410 | * | |
411 | * Returns 0 on success, -1 if an error occurred. | |
412 | */ | |
413 | static | |
414 | int lttng_ust_elf_get_build_id_from_segment( | |
415 | struct lttng_ust_elf *elf, uint8_t **build_id, size_t *length, | |
82ee1ee4 | 416 | off_t offset, off_t segment_end) |
8e2aed3f | 417 | { |
814d07b1 MD |
418 | uint8_t *_build_id = NULL; /* Silence old gcc warning. */ |
419 | size_t _length = 0; /* Silence old gcc warning. */ | |
8e2aed3f AB |
420 | |
421 | while (offset < segment_end) { | |
422 | struct lttng_ust_elf_nhdr nhdr; | |
405be658 | 423 | size_t read_len; |
8e2aed3f AB |
424 | |
425 | /* Align start of note entry */ | |
426 | offset += offset_align(offset, ELF_NOTE_ENTRY_ALIGN); | |
427 | if (offset >= segment_end) { | |
428 | break; | |
429 | } | |
430 | /* | |
431 | * We seek manually because if the note isn't the | |
432 | * build id the data following the header will not | |
433 | * have been read. | |
434 | */ | |
405be658 | 435 | if (lseek(elf->fd, offset, SEEK_SET) < 0) { |
8e2aed3f AB |
436 | goto error; |
437 | } | |
405be658 MD |
438 | if (lttng_ust_read(elf->fd, &nhdr, sizeof(nhdr)) |
439 | < sizeof(nhdr)) { | |
8e2aed3f AB |
440 | goto error; |
441 | } | |
442 | ||
443 | if (!is_elf_native_endian(elf)) { | |
444 | nhdr.n_namesz = bswap_32(nhdr.n_namesz); | |
445 | nhdr.n_descsz = bswap_32(nhdr.n_descsz); | |
446 | nhdr.n_type = bswap_32(nhdr.n_type); | |
447 | } | |
448 | ||
449 | offset += sizeof(nhdr) + nhdr.n_namesz; | |
450 | /* Align start of desc entry */ | |
451 | offset += offset_align(offset, ELF_NOTE_DESC_ALIGN); | |
452 | ||
453 | if (nhdr.n_type != NT_GNU_BUILD_ID) { | |
454 | /* | |
455 | * Ignore non build id notes but still | |
456 | * increase the offset. | |
457 | */ | |
458 | offset += nhdr.n_descsz; | |
459 | continue; | |
460 | } | |
461 | ||
462 | _length = nhdr.n_descsz; | |
463 | _build_id = zmalloc(sizeof(uint8_t) * _length); | |
5ada26b4 | 464 | if (!_build_id) { |
8e2aed3f AB |
465 | goto error; |
466 | } | |
467 | ||
405be658 | 468 | if (lseek(elf->fd, offset, SEEK_SET) < 0) { |
8e2aed3f AB |
469 | goto error; |
470 | } | |
405be658 MD |
471 | read_len = sizeof(*_build_id) * _length; |
472 | if (lttng_ust_read(elf->fd, _build_id, read_len) < read_len) { | |
8e2aed3f AB |
473 | goto error; |
474 | } | |
475 | ||
8e2aed3f AB |
476 | break; |
477 | } | |
478 | ||
82ee1ee4 | 479 | if (_build_id) { |
8e2aed3f AB |
480 | *build_id = _build_id; |
481 | *length = _length; | |
482 | } | |
483 | ||
8e2aed3f AB |
484 | return 0; |
485 | error: | |
83215d66 | 486 | free(_build_id); |
8e2aed3f AB |
487 | return -1; |
488 | } | |
489 | ||
490 | /* | |
491 | * Retrieve a build ID (an array of bytes) from the corresponding | |
492 | * section in the ELF file. The length of the build ID can be either | |
493 | * 16 or 20 bytes depending on the method used to generate it, hence | |
494 | * the length out parameter. | |
495 | * | |
496 | * If the function returns successfully, the out parameter `found` | |
497 | * indicates whether the build id information was present in the ELF | |
498 | * file or not. If `found` is not 0, the out parameters `build_id` and | |
499 | * `length` will both have been set with the retrieved information. | |
500 | * | |
501 | * Returns 0 on success, -1 if an error occurred. | |
502 | */ | |
503 | int lttng_ust_elf_get_build_id(struct lttng_ust_elf *elf, uint8_t **build_id, | |
504 | size_t *length, int *found) | |
505 | { | |
506 | uint16_t i; | |
8c83dbda MD |
507 | uint8_t *_build_id = NULL; /* Silence old gcc warning. */ |
508 | size_t _length = 0; /* Silence old gcc warning. */ | |
8e2aed3f AB |
509 | |
510 | if (!elf || !build_id || !length || !found) { | |
511 | goto error; | |
512 | } | |
513 | ||
514 | for (i = 0; i < elf->ehdr->e_phnum; ++i) { | |
f5a6717a | 515 | off_t offset, segment_end; |
8e2aed3f | 516 | struct lttng_ust_elf_phdr *phdr; |
5b3bbf98 | 517 | int ret = 0; |
8e2aed3f AB |
518 | |
519 | phdr = lttng_ust_elf_get_phdr(elf, i); | |
520 | if (!phdr) { | |
521 | goto error; | |
522 | } | |
523 | ||
524 | /* Build ID will be contained in a PT_NOTE segment. */ | |
525 | if (phdr->p_type != PT_NOTE) { | |
526 | goto next_loop; | |
527 | } | |
528 | ||
529 | offset = phdr->p_offset; | |
530 | segment_end = offset + phdr->p_filesz; | |
531 | ret = lttng_ust_elf_get_build_id_from_segment( | |
82ee1ee4 | 532 | elf, &_build_id, &_length, offset, segment_end); |
8e2aed3f AB |
533 | next_loop: |
534 | free(phdr); | |
535 | if (ret) { | |
536 | goto error; | |
537 | } | |
82ee1ee4 | 538 | if (_build_id) { |
8e2aed3f AB |
539 | break; |
540 | } | |
541 | } | |
542 | ||
82ee1ee4 | 543 | if (_build_id) { |
8e2aed3f AB |
544 | *build_id = _build_id; |
545 | *length = _length; | |
82ee1ee4 AB |
546 | *found = 1; |
547 | } else { | |
548 | *found = 0; | |
8e2aed3f AB |
549 | } |
550 | ||
8e2aed3f AB |
551 | return 0; |
552 | error: | |
99b7132d | 553 | free(_build_id); |
8e2aed3f AB |
554 | return -1; |
555 | } | |
556 | ||
557 | /* | |
558 | * Try to retrieve filename and CRC from given ELF section `shdr`. | |
559 | * | |
560 | * If the function returns successfully, the out parameter `found` | |
561 | * indicates whether the debug link information was present in the ELF | |
562 | * section or not. If `found` is not 0, the out parameters `filename` and | |
563 | * `crc` will both have been set with the retrieved information. | |
564 | * | |
565 | * Returns 0 on success, -1 if an error occurred. | |
566 | */ | |
8e2aed3f AB |
567 | int lttng_ust_elf_get_debug_link_from_section(struct lttng_ust_elf *elf, |
568 | char **filename, uint32_t *crc, | |
8e2aed3f AB |
569 | struct lttng_ust_elf_shdr *shdr) |
570 | { | |
8c83dbda | 571 | char *_filename = NULL; /* Silence old gcc warning. */ |
405be658 | 572 | size_t filename_len; |
8e2aed3f | 573 | char *section_name = NULL; |
8c83dbda | 574 | uint32_t _crc = 0; /* Silence old gcc warning. */ |
8e2aed3f | 575 | |
82ee1ee4 | 576 | if (!elf || !filename || !crc || !shdr) { |
8e2aed3f AB |
577 | goto error; |
578 | } | |
579 | ||
580 | /* | |
581 | * The .gnu_debuglink section is of type SHT_PROGBITS, | |
582 | * skip the other sections. | |
583 | */ | |
584 | if (shdr->sh_type != SHT_PROGBITS) { | |
585 | goto end; | |
586 | } | |
587 | ||
588 | section_name = lttng_ust_elf_get_section_name(elf, | |
589 | shdr->sh_name); | |
590 | if (!section_name) { | |
591 | goto end; | |
592 | } | |
593 | if (strcmp(section_name, ".gnu_debuglink")) { | |
594 | goto end; | |
595 | } | |
596 | ||
597 | /* | |
598 | * The length of the filename is the sh_size excluding the CRC | |
599 | * which comes after it in the section. | |
600 | */ | |
601 | _filename = zmalloc(sizeof(char) * (shdr->sh_size - ELF_CRC_SIZE)); | |
602 | if (!_filename) { | |
603 | goto error; | |
604 | } | |
405be658 | 605 | if (lseek(elf->fd, shdr->sh_offset, SEEK_SET) < 0) { |
8e2aed3f AB |
606 | goto error; |
607 | } | |
405be658 MD |
608 | filename_len = sizeof(*_filename) * (shdr->sh_size - ELF_CRC_SIZE); |
609 | if (lttng_ust_read(elf->fd, _filename, filename_len) < filename_len) { | |
8e2aed3f AB |
610 | goto error; |
611 | } | |
405be658 | 612 | if (lttng_ust_read(elf->fd, &_crc, sizeof(_crc)) < sizeof(_crc)) { |
8e2aed3f AB |
613 | goto error; |
614 | } | |
615 | if (!is_elf_native_endian(elf)) { | |
616 | _crc = bswap_32(_crc); | |
617 | } | |
618 | ||
8e2aed3f AB |
619 | end: |
620 | free(section_name); | |
82ee1ee4 | 621 | if (_filename) { |
8e2aed3f AB |
622 | *filename = _filename; |
623 | *crc = _crc; | |
624 | } | |
8e2aed3f AB |
625 | |
626 | return 0; | |
627 | ||
628 | error: | |
83215d66 MD |
629 | free(_filename); |
630 | free(section_name); | |
8e2aed3f AB |
631 | return -1; |
632 | } | |
633 | ||
634 | /* | |
635 | * Retrieve filename and CRC from ELF's .gnu_debuglink section, if any. | |
636 | * | |
637 | * If the function returns successfully, the out parameter `found` | |
638 | * indicates whether the debug link information was present in the ELF | |
639 | * file or not. If `found` is not 0, the out parameters `filename` and | |
640 | * `crc` will both have been set with the retrieved information. | |
641 | * | |
642 | * Returns 0 on success, -1 if an error occurred. | |
643 | */ | |
644 | int lttng_ust_elf_get_debug_link(struct lttng_ust_elf *elf, char **filename, | |
645 | uint32_t *crc, int *found) | |
646 | { | |
647 | int ret; | |
648 | uint16_t i; | |
8c83dbda MD |
649 | char *_filename = NULL; /* Silence old gcc warning. */ |
650 | uint32_t _crc = 0; /* Silence old gcc warning. */ | |
8e2aed3f AB |
651 | |
652 | if (!elf || !filename || !crc || !found) { | |
653 | goto error; | |
654 | } | |
655 | ||
656 | for (i = 0; i < elf->ehdr->e_shnum; ++i) { | |
657 | struct lttng_ust_elf_shdr *shdr = NULL; | |
658 | ||
659 | shdr = lttng_ust_elf_get_shdr(elf, i); | |
660 | if (!shdr) { | |
661 | goto error; | |
662 | } | |
663 | ||
664 | ret = lttng_ust_elf_get_debug_link_from_section( | |
82ee1ee4 | 665 | elf, &_filename, &_crc, shdr); |
8e2aed3f AB |
666 | free(shdr); |
667 | ||
668 | if (ret) { | |
669 | goto error; | |
670 | } | |
82ee1ee4 | 671 | if (_filename) { |
8e2aed3f AB |
672 | break; |
673 | } | |
674 | } | |
675 | ||
82ee1ee4 | 676 | if (_filename) { |
8e2aed3f AB |
677 | *filename = _filename; |
678 | *crc = _crc; | |
82ee1ee4 AB |
679 | *found = 1; |
680 | } else { | |
681 | *found = 0; | |
8e2aed3f AB |
682 | } |
683 | ||
8e2aed3f | 684 | return 0; |
82ee1ee4 | 685 | |
8e2aed3f | 686 | error: |
99b7132d | 687 | free(_filename); |
8e2aed3f AB |
688 | return -1; |
689 | } |