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> | |
97c7c238 | 28 | #include <stdbool.h> |
405be658 MD |
29 | #include "lttng-tracer-core.h" |
30 | ||
31 | #define BUF_LEN 4096 | |
8e2aed3f AB |
32 | |
33 | /* | |
34 | * Retrieve the nth (where n is the `index` argument) phdr (program | |
35 | * header) from the given elf instance. | |
36 | * | |
37 | * A pointer to the phdr is returned on success, NULL on failure. | |
38 | */ | |
39 | static | |
40 | struct lttng_ust_elf_phdr *lttng_ust_elf_get_phdr(struct lttng_ust_elf *elf, | |
41 | uint16_t index) | |
42 | { | |
43 | struct lttng_ust_elf_phdr *phdr = NULL; | |
f5a6717a | 44 | off_t offset; |
8e2aed3f AB |
45 | |
46 | if (!elf) { | |
47 | goto error; | |
48 | } | |
49 | ||
50 | if (index >= elf->ehdr->e_phnum) { | |
51 | goto error; | |
52 | } | |
53 | ||
54 | phdr = zmalloc(sizeof(struct lttng_ust_elf_phdr)); | |
55 | if (!phdr) { | |
56 | goto error; | |
57 | } | |
58 | ||
f5a6717a MD |
59 | offset = (off_t) elf->ehdr->e_phoff |
60 | + (off_t) index * elf->ehdr->e_phentsize; | |
405be658 | 61 | if (lseek(elf->fd, offset, SEEK_SET) < 0) { |
8e2aed3f AB |
62 | goto error; |
63 | } | |
64 | ||
65 | if (is_elf_32_bit(elf)) { | |
66 | Elf32_Phdr elf_phdr; | |
67 | ||
405be658 MD |
68 | if (lttng_ust_read(elf->fd, &elf_phdr, sizeof(elf_phdr)) |
69 | < sizeof(elf_phdr)) { | |
8e2aed3f AB |
70 | goto error; |
71 | } | |
72 | if (!is_elf_native_endian(elf)) { | |
73 | bswap_phdr(elf_phdr); | |
74 | } | |
75 | copy_phdr(elf_phdr, *phdr); | |
76 | } else { | |
77 | Elf64_Phdr elf_phdr; | |
78 | ||
405be658 MD |
79 | if (lttng_ust_read(elf->fd, &elf_phdr, sizeof(elf_phdr)) |
80 | < sizeof(elf_phdr)) { | |
8e2aed3f AB |
81 | goto error; |
82 | } | |
83 | if (!is_elf_native_endian(elf)) { | |
84 | bswap_phdr(elf_phdr); | |
85 | } | |
86 | copy_phdr(elf_phdr, *phdr); | |
87 | } | |
88 | ||
89 | return phdr; | |
90 | ||
91 | error: | |
92 | free(phdr); | |
93 | return NULL; | |
94 | } | |
95 | ||
96 | /* | |
97 | * Retrieve the nth (where n is the `index` argument) shdr (section | |
98 | * header) from the given elf instance. | |
99 | * | |
100 | * A pointer to the shdr is returned on success, NULL on failure. | |
101 | */ | |
102 | static | |
103 | struct lttng_ust_elf_shdr *lttng_ust_elf_get_shdr(struct lttng_ust_elf *elf, | |
104 | uint16_t index) | |
105 | { | |
106 | struct lttng_ust_elf_shdr *shdr = NULL; | |
4c5dac0d | 107 | off_t offset; |
8e2aed3f AB |
108 | |
109 | if (!elf) { | |
110 | goto error; | |
111 | } | |
112 | ||
113 | if (index >= elf->ehdr->e_shnum) { | |
114 | goto error; | |
115 | } | |
116 | ||
117 | shdr = zmalloc(sizeof(struct lttng_ust_elf_shdr)); | |
118 | if (!shdr) { | |
119 | goto error; | |
120 | } | |
121 | ||
4c5dac0d | 122 | offset = (off_t) elf->ehdr->e_shoff |
5a26ac54 | 123 | + (off_t) index * elf->ehdr->e_shentsize; |
405be658 | 124 | if (lseek(elf->fd, offset, SEEK_SET) < 0) { |
8e2aed3f AB |
125 | goto error; |
126 | } | |
127 | ||
128 | if (is_elf_32_bit(elf)) { | |
129 | Elf32_Shdr elf_shdr; | |
130 | ||
405be658 MD |
131 | if (lttng_ust_read(elf->fd, &elf_shdr, sizeof(elf_shdr)) |
132 | < sizeof(elf_shdr)) { | |
8e2aed3f AB |
133 | goto error; |
134 | } | |
135 | if (!is_elf_native_endian(elf)) { | |
136 | bswap_shdr(elf_shdr); | |
137 | } | |
138 | copy_shdr(elf_shdr, *shdr); | |
139 | } else { | |
140 | Elf64_Shdr elf_shdr; | |
141 | ||
405be658 MD |
142 | if (lttng_ust_read(elf->fd, &elf_shdr, sizeof(elf_shdr)) |
143 | < sizeof(elf_shdr)) { | |
8e2aed3f AB |
144 | goto error; |
145 | } | |
146 | if (!is_elf_native_endian(elf)) { | |
147 | bswap_shdr(elf_shdr); | |
148 | } | |
149 | copy_shdr(elf_shdr, *shdr); | |
150 | } | |
151 | ||
152 | return shdr; | |
153 | ||
154 | error: | |
155 | free(shdr); | |
156 | return NULL; | |
157 | } | |
158 | ||
159 | /* | |
160 | * Lookup a section's name from a given offset (usually from an shdr's | |
161 | * sh_name value) in bytes relative to the beginning of the section | |
162 | * names string table. | |
163 | * | |
164 | * If no name is found, NULL is returned. | |
165 | */ | |
166 | static | |
f5a6717a | 167 | char *lttng_ust_elf_get_section_name(struct lttng_ust_elf *elf, off_t offset) |
8e2aed3f AB |
168 | { |
169 | char *name = NULL; | |
405be658 | 170 | size_t len = 0, to_read; /* len does not include \0 */ |
8e2aed3f AB |
171 | |
172 | if (!elf) { | |
173 | goto error; | |
174 | } | |
175 | ||
176 | if (offset >= elf->section_names_size) { | |
177 | goto error; | |
178 | } | |
179 | ||
405be658 | 180 | if (lseek(elf->fd, elf->section_names_offset + offset, SEEK_SET) < 0) { |
8e2aed3f AB |
181 | goto error; |
182 | } | |
405be658 MD |
183 | |
184 | to_read = elf->section_names_size - offset; | |
185 | ||
186 | /* Find first \0 after or at current location, remember len. */ | |
187 | for (;;) { | |
188 | char buf[BUF_LEN]; | |
189 | ssize_t read_len; | |
190 | size_t i; | |
191 | ||
192 | if (!to_read) { | |
8e2aed3f | 193 | goto error; |
8e2aed3f | 194 | } |
405be658 MD |
195 | read_len = lttng_ust_read(elf->fd, buf, |
196 | min_t(size_t, BUF_LEN, to_read)); | |
197 | if (read_len <= 0) { | |
198 | goto error; | |
199 | } | |
200 | for (i = 0; i < read_len; i++) { | |
201 | if (buf[i] == '\0') { | |
202 | len += i; | |
203 | goto end; | |
204 | } | |
205 | } | |
206 | len += read_len; | |
207 | to_read -= read_len; | |
8e2aed3f | 208 | } |
8e2aed3f | 209 | end: |
405be658 | 210 | name = zmalloc(sizeof(char) * (len + 1)); /* + 1 for \0 */ |
8e2aed3f AB |
211 | if (!name) { |
212 | goto error; | |
213 | } | |
405be658 MD |
214 | if (lseek(elf->fd, elf->section_names_offset + offset, |
215 | SEEK_SET) < 0) { | |
8e2aed3f AB |
216 | goto error; |
217 | } | |
405be658 | 218 | if (lttng_ust_read(elf->fd, name, len + 1) < len + 1) { |
8e2aed3f AB |
219 | goto error; |
220 | } | |
221 | ||
222 | return name; | |
223 | ||
224 | error: | |
225 | free(name); | |
226 | return NULL; | |
227 | } | |
228 | ||
229 | /* | |
230 | * Create an instance of lttng_ust_elf for the ELF file located at | |
231 | * `path`. | |
232 | * | |
233 | * Return a pointer to the instance on success, NULL on failure. | |
234 | */ | |
235 | struct lttng_ust_elf *lttng_ust_elf_create(const char *path) | |
236 | { | |
237 | uint8_t e_ident[EI_NIDENT]; | |
238 | struct lttng_ust_elf_shdr *section_names_shdr; | |
405be658 | 239 | struct lttng_ust_elf *elf = NULL; |
8e2aed3f AB |
240 | |
241 | elf = zmalloc(sizeof(struct lttng_ust_elf)); | |
242 | if (!elf) { | |
243 | goto error; | |
244 | } | |
245 | ||
246 | elf->path = strdup(path); | |
247 | if (!elf->path) { | |
248 | goto error; | |
249 | } | |
250 | ||
405be658 MD |
251 | elf->fd = open(elf->path, O_RDONLY | O_CLOEXEC); |
252 | if (elf->fd < 0) { | |
8e2aed3f AB |
253 | goto error; |
254 | } | |
255 | ||
405be658 | 256 | if (lttng_ust_read(elf->fd, e_ident, EI_NIDENT) < EI_NIDENT) { |
8e2aed3f AB |
257 | goto error; |
258 | } | |
259 | elf->bitness = e_ident[EI_CLASS]; | |
260 | elf->endianness = e_ident[EI_DATA]; | |
405be658 MD |
261 | |
262 | if (lseek(elf->fd, 0, SEEK_SET) < 0) { | |
263 | goto error; | |
264 | } | |
8e2aed3f AB |
265 | |
266 | elf->ehdr = zmalloc(sizeof(struct lttng_ust_elf_ehdr)); | |
267 | if (!elf->ehdr) { | |
268 | goto error; | |
269 | } | |
270 | ||
271 | if (is_elf_32_bit(elf)) { | |
272 | Elf32_Ehdr elf_ehdr; | |
273 | ||
405be658 MD |
274 | if (lttng_ust_read(elf->fd, &elf_ehdr, sizeof(elf_ehdr)) |
275 | < sizeof(elf_ehdr)) { | |
8e2aed3f AB |
276 | goto error; |
277 | } | |
278 | if (!is_elf_native_endian(elf)) { | |
279 | bswap_ehdr(elf_ehdr); | |
280 | } | |
281 | copy_ehdr(elf_ehdr, *(elf->ehdr)); | |
282 | } else { | |
283 | Elf64_Ehdr elf_ehdr; | |
284 | ||
405be658 MD |
285 | if (lttng_ust_read(elf->fd, &elf_ehdr, sizeof(elf_ehdr)) |
286 | < sizeof(elf_ehdr)) { | |
8e2aed3f AB |
287 | goto error; |
288 | } | |
289 | if (!is_elf_native_endian(elf)) { | |
290 | bswap_ehdr(elf_ehdr); | |
291 | } | |
292 | copy_ehdr(elf_ehdr, *(elf->ehdr)); | |
293 | } | |
294 | ||
295 | section_names_shdr = lttng_ust_elf_get_shdr(elf, elf->ehdr->e_shstrndx); | |
296 | if (!section_names_shdr) { | |
297 | goto error; | |
298 | } | |
299 | ||
300 | elf->section_names_offset = section_names_shdr->sh_offset; | |
301 | elf->section_names_size = section_names_shdr->sh_size; | |
302 | ||
303 | free(section_names_shdr); | |
8e2aed3f AB |
304 | return elf; |
305 | ||
306 | error: | |
307 | if (elf) { | |
308 | free(elf->ehdr); | |
405be658 MD |
309 | if (elf->fd >= 0) { |
310 | if (close(elf->fd)) { | |
311 | abort(); | |
312 | } | |
313 | } | |
8e2aed3f | 314 | free(elf->path); |
405be658 | 315 | free(elf); |
8e2aed3f | 316 | } |
8e2aed3f AB |
317 | return NULL; |
318 | } | |
319 | ||
f5eb039d AB |
320 | /* |
321 | * Test whether the ELF file is position independent code (PIC) | |
322 | */ | |
323 | uint8_t lttng_ust_elf_is_pic(struct lttng_ust_elf *elf) | |
324 | { | |
325 | /* | |
326 | * PIC has and e_type value of ET_DYN, see ELF specification | |
327 | * version 1.1 p. 1-3. | |
328 | */ | |
329 | return elf->ehdr->e_type == ET_DYN; | |
330 | } | |
331 | ||
8e2aed3f AB |
332 | /* |
333 | * Destroy the given lttng_ust_elf instance. | |
334 | */ | |
335 | void lttng_ust_elf_destroy(struct lttng_ust_elf *elf) | |
336 | { | |
337 | if (!elf) { | |
338 | return; | |
339 | } | |
340 | ||
341 | free(elf->ehdr); | |
405be658 MD |
342 | if (close(elf->fd)) { |
343 | abort(); | |
344 | } | |
8e2aed3f AB |
345 | free(elf->path); |
346 | free(elf); | |
347 | } | |
348 | ||
349 | /* | |
350 | * Compute the total in-memory size of the ELF file, in bytes. | |
351 | * | |
352 | * Returns 0 if successful, -1 if not. On success, the memory size is | |
353 | * returned through the out parameter `memsz`. | |
354 | */ | |
355 | int lttng_ust_elf_get_memsz(struct lttng_ust_elf *elf, uint64_t *memsz) | |
356 | { | |
357 | uint16_t i; | |
e1f0c569 | 358 | uint64_t low_addr = UINT64_MAX, high_addr = 0; |
8e2aed3f AB |
359 | |
360 | if (!elf || !memsz) { | |
361 | goto error; | |
362 | } | |
363 | ||
364 | for (i = 0; i < elf->ehdr->e_phnum; ++i) { | |
365 | struct lttng_ust_elf_phdr *phdr; | |
8e2aed3f AB |
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 | ||
8886accb MD |
380 | low_addr = min_t(uint64_t, low_addr, phdr->p_vaddr); |
381 | high_addr = max_t(uint64_t, high_addr, | |
382 | phdr->p_vaddr + phdr->p_memsz); | |
8e2aed3f AB |
383 | next_loop: |
384 | free(phdr); | |
385 | } | |
386 | ||
e1f0c569 AB |
387 | if (high_addr < low_addr) { |
388 | /* No PT_LOAD segments or corrupted data. */ | |
389 | goto error; | |
390 | } | |
391 | ||
392 | *memsz = high_addr - low_addr; | |
8e2aed3f AB |
393 | return 0; |
394 | error: | |
395 | return -1; | |
396 | } | |
397 | ||
398 | /* | |
399 | * Internal method used to try and get the build_id from a PT_NOTE | |
400 | * segment ranging from `offset` to `segment_end`. | |
401 | * | |
402 | * If the function returns successfully, the out parameter `found` | |
403 | * indicates whether the build id information was present in the | |
404 | * segment or not. If `found` is not 0, the out parameters `build_id` | |
405 | * and `length` will both have been set with the retrieved | |
406 | * information. | |
407 | * | |
408 | * Returns 0 on success, -1 if an error occurred. | |
409 | */ | |
410 | static | |
411 | int lttng_ust_elf_get_build_id_from_segment( | |
412 | struct lttng_ust_elf *elf, uint8_t **build_id, size_t *length, | |
82ee1ee4 | 413 | off_t offset, off_t segment_end) |
8e2aed3f | 414 | { |
814d07b1 MD |
415 | uint8_t *_build_id = NULL; /* Silence old gcc warning. */ |
416 | size_t _length = 0; /* Silence old gcc warning. */ | |
8e2aed3f AB |
417 | |
418 | while (offset < segment_end) { | |
419 | struct lttng_ust_elf_nhdr nhdr; | |
405be658 | 420 | size_t read_len; |
8e2aed3f AB |
421 | |
422 | /* Align start of note entry */ | |
423 | offset += offset_align(offset, ELF_NOTE_ENTRY_ALIGN); | |
424 | if (offset >= segment_end) { | |
425 | break; | |
426 | } | |
427 | /* | |
428 | * We seek manually because if the note isn't the | |
429 | * build id the data following the header will not | |
430 | * have been read. | |
431 | */ | |
405be658 | 432 | if (lseek(elf->fd, offset, SEEK_SET) < 0) { |
8e2aed3f AB |
433 | goto error; |
434 | } | |
405be658 MD |
435 | if (lttng_ust_read(elf->fd, &nhdr, sizeof(nhdr)) |
436 | < sizeof(nhdr)) { | |
8e2aed3f AB |
437 | goto error; |
438 | } | |
439 | ||
440 | if (!is_elf_native_endian(elf)) { | |
441 | nhdr.n_namesz = bswap_32(nhdr.n_namesz); | |
442 | nhdr.n_descsz = bswap_32(nhdr.n_descsz); | |
443 | nhdr.n_type = bswap_32(nhdr.n_type); | |
444 | } | |
445 | ||
446 | offset += sizeof(nhdr) + nhdr.n_namesz; | |
447 | /* Align start of desc entry */ | |
448 | offset += offset_align(offset, ELF_NOTE_DESC_ALIGN); | |
449 | ||
450 | if (nhdr.n_type != NT_GNU_BUILD_ID) { | |
451 | /* | |
452 | * Ignore non build id notes but still | |
453 | * increase the offset. | |
454 | */ | |
455 | offset += nhdr.n_descsz; | |
456 | continue; | |
457 | } | |
458 | ||
459 | _length = nhdr.n_descsz; | |
460 | _build_id = zmalloc(sizeof(uint8_t) * _length); | |
5ada26b4 | 461 | if (!_build_id) { |
8e2aed3f AB |
462 | goto error; |
463 | } | |
464 | ||
405be658 | 465 | if (lseek(elf->fd, offset, SEEK_SET) < 0) { |
8e2aed3f AB |
466 | goto error; |
467 | } | |
405be658 MD |
468 | read_len = sizeof(*_build_id) * _length; |
469 | if (lttng_ust_read(elf->fd, _build_id, read_len) < read_len) { | |
8e2aed3f AB |
470 | goto error; |
471 | } | |
472 | ||
8e2aed3f AB |
473 | break; |
474 | } | |
475 | ||
82ee1ee4 | 476 | if (_build_id) { |
8e2aed3f AB |
477 | *build_id = _build_id; |
478 | *length = _length; | |
479 | } | |
480 | ||
8e2aed3f AB |
481 | return 0; |
482 | error: | |
83215d66 | 483 | free(_build_id); |
8e2aed3f AB |
484 | return -1; |
485 | } | |
486 | ||
487 | /* | |
488 | * Retrieve a build ID (an array of bytes) from the corresponding | |
489 | * section in the ELF file. The length of the build ID can be either | |
490 | * 16 or 20 bytes depending on the method used to generate it, hence | |
491 | * the length out parameter. | |
492 | * | |
493 | * If the function returns successfully, the out parameter `found` | |
494 | * indicates whether the build id information was present in the ELF | |
495 | * file or not. If `found` is not 0, the out parameters `build_id` and | |
496 | * `length` will both have been set with the retrieved information. | |
497 | * | |
498 | * Returns 0 on success, -1 if an error occurred. | |
499 | */ | |
500 | int lttng_ust_elf_get_build_id(struct lttng_ust_elf *elf, uint8_t **build_id, | |
501 | size_t *length, int *found) | |
502 | { | |
503 | uint16_t i; | |
8c83dbda MD |
504 | uint8_t *_build_id = NULL; /* Silence old gcc warning. */ |
505 | size_t _length = 0; /* Silence old gcc warning. */ | |
8e2aed3f AB |
506 | |
507 | if (!elf || !build_id || !length || !found) { | |
508 | goto error; | |
509 | } | |
510 | ||
511 | for (i = 0; i < elf->ehdr->e_phnum; ++i) { | |
f5a6717a | 512 | off_t offset, segment_end; |
8e2aed3f | 513 | struct lttng_ust_elf_phdr *phdr; |
5b3bbf98 | 514 | int ret = 0; |
8e2aed3f AB |
515 | |
516 | phdr = lttng_ust_elf_get_phdr(elf, i); | |
517 | if (!phdr) { | |
518 | goto error; | |
519 | } | |
520 | ||
521 | /* Build ID will be contained in a PT_NOTE segment. */ | |
522 | if (phdr->p_type != PT_NOTE) { | |
523 | goto next_loop; | |
524 | } | |
525 | ||
526 | offset = phdr->p_offset; | |
527 | segment_end = offset + phdr->p_filesz; | |
528 | ret = lttng_ust_elf_get_build_id_from_segment( | |
82ee1ee4 | 529 | elf, &_build_id, &_length, offset, segment_end); |
8e2aed3f AB |
530 | next_loop: |
531 | free(phdr); | |
532 | if (ret) { | |
533 | goto error; | |
534 | } | |
82ee1ee4 | 535 | if (_build_id) { |
8e2aed3f AB |
536 | break; |
537 | } | |
538 | } | |
539 | ||
82ee1ee4 | 540 | if (_build_id) { |
8e2aed3f AB |
541 | *build_id = _build_id; |
542 | *length = _length; | |
82ee1ee4 AB |
543 | *found = 1; |
544 | } else { | |
545 | *found = 0; | |
8e2aed3f AB |
546 | } |
547 | ||
8e2aed3f AB |
548 | return 0; |
549 | error: | |
99b7132d | 550 | free(_build_id); |
8e2aed3f AB |
551 | return -1; |
552 | } | |
553 | ||
554 | /* | |
555 | * Try to retrieve filename and CRC from given ELF section `shdr`. | |
556 | * | |
557 | * If the function returns successfully, the out parameter `found` | |
558 | * indicates whether the debug link information was present in the ELF | |
559 | * section or not. If `found` is not 0, the out parameters `filename` and | |
560 | * `crc` will both have been set with the retrieved information. | |
561 | * | |
562 | * Returns 0 on success, -1 if an error occurred. | |
563 | */ | |
8e2aed3f AB |
564 | int lttng_ust_elf_get_debug_link_from_section(struct lttng_ust_elf *elf, |
565 | char **filename, uint32_t *crc, | |
8e2aed3f AB |
566 | struct lttng_ust_elf_shdr *shdr) |
567 | { | |
8c83dbda | 568 | char *_filename = NULL; /* Silence old gcc warning. */ |
405be658 | 569 | size_t filename_len; |
8e2aed3f | 570 | char *section_name = NULL; |
8c83dbda | 571 | uint32_t _crc = 0; /* Silence old gcc warning. */ |
8e2aed3f | 572 | |
82ee1ee4 | 573 | if (!elf || !filename || !crc || !shdr) { |
8e2aed3f AB |
574 | goto error; |
575 | } | |
576 | ||
577 | /* | |
578 | * The .gnu_debuglink section is of type SHT_PROGBITS, | |
579 | * skip the other sections. | |
580 | */ | |
581 | if (shdr->sh_type != SHT_PROGBITS) { | |
582 | goto end; | |
583 | } | |
584 | ||
585 | section_name = lttng_ust_elf_get_section_name(elf, | |
586 | shdr->sh_name); | |
587 | if (!section_name) { | |
588 | goto end; | |
589 | } | |
590 | if (strcmp(section_name, ".gnu_debuglink")) { | |
591 | goto end; | |
592 | } | |
593 | ||
594 | /* | |
595 | * The length of the filename is the sh_size excluding the CRC | |
596 | * which comes after it in the section. | |
597 | */ | |
598 | _filename = zmalloc(sizeof(char) * (shdr->sh_size - ELF_CRC_SIZE)); | |
599 | if (!_filename) { | |
600 | goto error; | |
601 | } | |
405be658 | 602 | if (lseek(elf->fd, shdr->sh_offset, SEEK_SET) < 0) { |
8e2aed3f AB |
603 | goto error; |
604 | } | |
405be658 MD |
605 | filename_len = sizeof(*_filename) * (shdr->sh_size - ELF_CRC_SIZE); |
606 | if (lttng_ust_read(elf->fd, _filename, filename_len) < filename_len) { | |
8e2aed3f AB |
607 | goto error; |
608 | } | |
405be658 | 609 | if (lttng_ust_read(elf->fd, &_crc, sizeof(_crc)) < sizeof(_crc)) { |
8e2aed3f AB |
610 | goto error; |
611 | } | |
612 | if (!is_elf_native_endian(elf)) { | |
613 | _crc = bswap_32(_crc); | |
614 | } | |
615 | ||
8e2aed3f AB |
616 | end: |
617 | free(section_name); | |
82ee1ee4 | 618 | if (_filename) { |
8e2aed3f AB |
619 | *filename = _filename; |
620 | *crc = _crc; | |
621 | } | |
8e2aed3f AB |
622 | |
623 | return 0; | |
624 | ||
625 | error: | |
83215d66 MD |
626 | free(_filename); |
627 | free(section_name); | |
8e2aed3f AB |
628 | return -1; |
629 | } | |
630 | ||
631 | /* | |
632 | * Retrieve filename and CRC from ELF's .gnu_debuglink section, if any. | |
633 | * | |
634 | * If the function returns successfully, the out parameter `found` | |
635 | * indicates whether the debug link information was present in the ELF | |
636 | * file or not. If `found` is not 0, the out parameters `filename` and | |
637 | * `crc` will both have been set with the retrieved information. | |
638 | * | |
639 | * Returns 0 on success, -1 if an error occurred. | |
640 | */ | |
641 | int lttng_ust_elf_get_debug_link(struct lttng_ust_elf *elf, char **filename, | |
642 | uint32_t *crc, int *found) | |
643 | { | |
644 | int ret; | |
645 | uint16_t i; | |
8c83dbda MD |
646 | char *_filename = NULL; /* Silence old gcc warning. */ |
647 | uint32_t _crc = 0; /* Silence old gcc warning. */ | |
8e2aed3f AB |
648 | |
649 | if (!elf || !filename || !crc || !found) { | |
650 | goto error; | |
651 | } | |
652 | ||
653 | for (i = 0; i < elf->ehdr->e_shnum; ++i) { | |
654 | struct lttng_ust_elf_shdr *shdr = NULL; | |
655 | ||
656 | shdr = lttng_ust_elf_get_shdr(elf, i); | |
657 | if (!shdr) { | |
658 | goto error; | |
659 | } | |
660 | ||
661 | ret = lttng_ust_elf_get_debug_link_from_section( | |
82ee1ee4 | 662 | elf, &_filename, &_crc, shdr); |
8e2aed3f AB |
663 | free(shdr); |
664 | ||
665 | if (ret) { | |
666 | goto error; | |
667 | } | |
82ee1ee4 | 668 | if (_filename) { |
8e2aed3f AB |
669 | break; |
670 | } | |
671 | } | |
672 | ||
82ee1ee4 | 673 | if (_filename) { |
8e2aed3f AB |
674 | *filename = _filename; |
675 | *crc = _crc; | |
82ee1ee4 AB |
676 | *found = 1; |
677 | } else { | |
678 | *found = 0; | |
8e2aed3f AB |
679 | } |
680 | ||
8e2aed3f | 681 | return 0; |
82ee1ee4 | 682 | |
8e2aed3f | 683 | error: |
99b7132d | 684 | free(_filename); |
8e2aed3f AB |
685 | return -1; |
686 | } |