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 |
3fbec7dc | 20 | #define _LGPL_SOURCE |
8e2aed3f AB |
21 | #include <helper.h> |
22 | #include <string.h> | |
23 | #include <lttng/align.h> | |
24 | #include <lttng/ust-elf.h> | |
405be658 MD |
25 | #include <sys/types.h> |
26 | #include <sys/stat.h> | |
27 | #include <fcntl.h> | |
28 | #include <unistd.h> | |
97c7c238 | 29 | #include <stdbool.h> |
4fc6ea30 | 30 | #include <ust-fd.h> |
405be658 MD |
31 | #include "lttng-tracer-core.h" |
32 | ||
33 | #define BUF_LEN 4096 | |
8e2aed3f | 34 | |
71bf0951 PP |
35 | #ifndef NT_GNU_BUILD_ID |
36 | # define NT_GNU_BUILD_ID 3 | |
37 | #endif | |
38 | ||
8e2aed3f AB |
39 | /* |
40 | * Retrieve the nth (where n is the `index` argument) phdr (program | |
41 | * header) from the given elf instance. | |
42 | * | |
43 | * A pointer to the phdr is returned on success, NULL on failure. | |
44 | */ | |
45 | static | |
46 | struct lttng_ust_elf_phdr *lttng_ust_elf_get_phdr(struct lttng_ust_elf *elf, | |
47 | uint16_t index) | |
48 | { | |
49 | struct lttng_ust_elf_phdr *phdr = NULL; | |
f5a6717a | 50 | off_t offset; |
8e2aed3f AB |
51 | |
52 | if (!elf) { | |
53 | goto error; | |
54 | } | |
55 | ||
56 | if (index >= elf->ehdr->e_phnum) { | |
57 | goto error; | |
58 | } | |
59 | ||
60 | phdr = zmalloc(sizeof(struct lttng_ust_elf_phdr)); | |
61 | if (!phdr) { | |
62 | goto error; | |
63 | } | |
64 | ||
f5a6717a MD |
65 | offset = (off_t) elf->ehdr->e_phoff |
66 | + (off_t) index * elf->ehdr->e_phentsize; | |
405be658 | 67 | if (lseek(elf->fd, offset, SEEK_SET) < 0) { |
8e2aed3f AB |
68 | goto error; |
69 | } | |
70 | ||
71 | if (is_elf_32_bit(elf)) { | |
72 | Elf32_Phdr elf_phdr; | |
73 | ||
405be658 MD |
74 | if (lttng_ust_read(elf->fd, &elf_phdr, sizeof(elf_phdr)) |
75 | < sizeof(elf_phdr)) { | |
8e2aed3f AB |
76 | goto error; |
77 | } | |
78 | if (!is_elf_native_endian(elf)) { | |
79 | bswap_phdr(elf_phdr); | |
80 | } | |
81 | copy_phdr(elf_phdr, *phdr); | |
82 | } else { | |
83 | Elf64_Phdr elf_phdr; | |
84 | ||
405be658 MD |
85 | if (lttng_ust_read(elf->fd, &elf_phdr, sizeof(elf_phdr)) |
86 | < sizeof(elf_phdr)) { | |
8e2aed3f AB |
87 | goto error; |
88 | } | |
89 | if (!is_elf_native_endian(elf)) { | |
90 | bswap_phdr(elf_phdr); | |
91 | } | |
92 | copy_phdr(elf_phdr, *phdr); | |
93 | } | |
94 | ||
95 | return phdr; | |
96 | ||
97 | error: | |
98 | free(phdr); | |
99 | return NULL; | |
100 | } | |
101 | ||
102 | /* | |
103 | * Retrieve the nth (where n is the `index` argument) shdr (section | |
104 | * header) from the given elf instance. | |
105 | * | |
106 | * A pointer to the shdr is returned on success, NULL on failure. | |
107 | */ | |
108 | static | |
109 | struct lttng_ust_elf_shdr *lttng_ust_elf_get_shdr(struct lttng_ust_elf *elf, | |
110 | uint16_t index) | |
111 | { | |
112 | struct lttng_ust_elf_shdr *shdr = NULL; | |
4c5dac0d | 113 | off_t offset; |
8e2aed3f AB |
114 | |
115 | if (!elf) { | |
116 | goto error; | |
117 | } | |
118 | ||
119 | if (index >= elf->ehdr->e_shnum) { | |
120 | goto error; | |
121 | } | |
122 | ||
123 | shdr = zmalloc(sizeof(struct lttng_ust_elf_shdr)); | |
124 | if (!shdr) { | |
125 | goto error; | |
126 | } | |
127 | ||
4c5dac0d | 128 | offset = (off_t) elf->ehdr->e_shoff |
5a26ac54 | 129 | + (off_t) index * elf->ehdr->e_shentsize; |
405be658 | 130 | if (lseek(elf->fd, offset, SEEK_SET) < 0) { |
8e2aed3f AB |
131 | goto error; |
132 | } | |
133 | ||
134 | if (is_elf_32_bit(elf)) { | |
135 | Elf32_Shdr elf_shdr; | |
136 | ||
405be658 MD |
137 | if (lttng_ust_read(elf->fd, &elf_shdr, sizeof(elf_shdr)) |
138 | < sizeof(elf_shdr)) { | |
8e2aed3f AB |
139 | goto error; |
140 | } | |
141 | if (!is_elf_native_endian(elf)) { | |
142 | bswap_shdr(elf_shdr); | |
143 | } | |
144 | copy_shdr(elf_shdr, *shdr); | |
145 | } else { | |
146 | Elf64_Shdr elf_shdr; | |
147 | ||
405be658 MD |
148 | if (lttng_ust_read(elf->fd, &elf_shdr, sizeof(elf_shdr)) |
149 | < sizeof(elf_shdr)) { | |
8e2aed3f AB |
150 | goto error; |
151 | } | |
152 | if (!is_elf_native_endian(elf)) { | |
153 | bswap_shdr(elf_shdr); | |
154 | } | |
155 | copy_shdr(elf_shdr, *shdr); | |
156 | } | |
157 | ||
158 | return shdr; | |
159 | ||
160 | error: | |
161 | free(shdr); | |
162 | return NULL; | |
163 | } | |
164 | ||
165 | /* | |
166 | * Lookup a section's name from a given offset (usually from an shdr's | |
167 | * sh_name value) in bytes relative to the beginning of the section | |
168 | * names string table. | |
169 | * | |
170 | * If no name is found, NULL is returned. | |
171 | */ | |
172 | static | |
f5a6717a | 173 | char *lttng_ust_elf_get_section_name(struct lttng_ust_elf *elf, off_t offset) |
8e2aed3f AB |
174 | { |
175 | char *name = NULL; | |
405be658 | 176 | size_t len = 0, to_read; /* len does not include \0 */ |
8e2aed3f AB |
177 | |
178 | if (!elf) { | |
179 | goto error; | |
180 | } | |
181 | ||
182 | if (offset >= elf->section_names_size) { | |
183 | goto error; | |
184 | } | |
185 | ||
405be658 | 186 | if (lseek(elf->fd, elf->section_names_offset + offset, SEEK_SET) < 0) { |
8e2aed3f AB |
187 | goto error; |
188 | } | |
405be658 MD |
189 | |
190 | to_read = elf->section_names_size - offset; | |
191 | ||
192 | /* Find first \0 after or at current location, remember len. */ | |
193 | for (;;) { | |
194 | char buf[BUF_LEN]; | |
195 | ssize_t read_len; | |
196 | size_t i; | |
197 | ||
198 | if (!to_read) { | |
8e2aed3f | 199 | goto error; |
8e2aed3f | 200 | } |
405be658 MD |
201 | read_len = lttng_ust_read(elf->fd, buf, |
202 | min_t(size_t, BUF_LEN, to_read)); | |
203 | if (read_len <= 0) { | |
204 | goto error; | |
205 | } | |
206 | for (i = 0; i < read_len; i++) { | |
207 | if (buf[i] == '\0') { | |
208 | len += i; | |
209 | goto end; | |
210 | } | |
211 | } | |
212 | len += read_len; | |
213 | to_read -= read_len; | |
8e2aed3f | 214 | } |
8e2aed3f | 215 | end: |
405be658 | 216 | name = zmalloc(sizeof(char) * (len + 1)); /* + 1 for \0 */ |
8e2aed3f AB |
217 | if (!name) { |
218 | goto error; | |
219 | } | |
405be658 MD |
220 | if (lseek(elf->fd, elf->section_names_offset + offset, |
221 | SEEK_SET) < 0) { | |
8e2aed3f AB |
222 | goto error; |
223 | } | |
405be658 | 224 | if (lttng_ust_read(elf->fd, name, len + 1) < len + 1) { |
8e2aed3f AB |
225 | goto error; |
226 | } | |
227 | ||
228 | return name; | |
229 | ||
230 | error: | |
231 | free(name); | |
232 | return NULL; | |
233 | } | |
234 | ||
235 | /* | |
236 | * Create an instance of lttng_ust_elf for the ELF file located at | |
237 | * `path`. | |
238 | * | |
239 | * Return a pointer to the instance on success, NULL on failure. | |
240 | */ | |
241 | struct lttng_ust_elf *lttng_ust_elf_create(const char *path) | |
242 | { | |
243 | uint8_t e_ident[EI_NIDENT]; | |
244 | struct lttng_ust_elf_shdr *section_names_shdr; | |
405be658 | 245 | struct lttng_ust_elf *elf = NULL; |
8e2aed3f AB |
246 | |
247 | elf = zmalloc(sizeof(struct lttng_ust_elf)); | |
248 | if (!elf) { | |
249 | goto error; | |
250 | } | |
251 | ||
4fc6ea30 | 252 | |
8e2aed3f AB |
253 | elf->path = strdup(path); |
254 | if (!elf->path) { | |
255 | goto error; | |
256 | } | |
257 | ||
4fc6ea30 | 258 | lttng_ust_lock_fd_tracker(); |
405be658 MD |
259 | elf->fd = open(elf->path, O_RDONLY | O_CLOEXEC); |
260 | if (elf->fd < 0) { | |
4fc6ea30 | 261 | lttng_ust_unlock_fd_tracker(); |
8e2aed3f AB |
262 | goto error; |
263 | } | |
4fc6ea30 JR |
264 | lttng_ust_add_fd_to_tracker(elf->fd); |
265 | lttng_ust_unlock_fd_tracker(); | |
8e2aed3f | 266 | |
405be658 | 267 | if (lttng_ust_read(elf->fd, e_ident, EI_NIDENT) < EI_NIDENT) { |
8e2aed3f AB |
268 | goto error; |
269 | } | |
270 | elf->bitness = e_ident[EI_CLASS]; | |
271 | elf->endianness = e_ident[EI_DATA]; | |
405be658 MD |
272 | |
273 | if (lseek(elf->fd, 0, SEEK_SET) < 0) { | |
274 | goto error; | |
275 | } | |
8e2aed3f AB |
276 | |
277 | elf->ehdr = zmalloc(sizeof(struct lttng_ust_elf_ehdr)); | |
278 | if (!elf->ehdr) { | |
279 | goto error; | |
280 | } | |
281 | ||
282 | if (is_elf_32_bit(elf)) { | |
283 | Elf32_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 | } else { | |
294 | Elf64_Ehdr elf_ehdr; | |
295 | ||
405be658 MD |
296 | if (lttng_ust_read(elf->fd, &elf_ehdr, sizeof(elf_ehdr)) |
297 | < sizeof(elf_ehdr)) { | |
8e2aed3f AB |
298 | goto error; |
299 | } | |
300 | if (!is_elf_native_endian(elf)) { | |
301 | bswap_ehdr(elf_ehdr); | |
302 | } | |
303 | copy_ehdr(elf_ehdr, *(elf->ehdr)); | |
304 | } | |
305 | ||
306 | section_names_shdr = lttng_ust_elf_get_shdr(elf, elf->ehdr->e_shstrndx); | |
307 | if (!section_names_shdr) { | |
308 | goto error; | |
309 | } | |
310 | ||
311 | elf->section_names_offset = section_names_shdr->sh_offset; | |
312 | elf->section_names_size = section_names_shdr->sh_size; | |
313 | ||
314 | free(section_names_shdr); | |
8e2aed3f AB |
315 | return elf; |
316 | ||
317 | error: | |
4fc6ea30 | 318 | lttng_ust_elf_destroy(elf); |
8e2aed3f AB |
319 | return NULL; |
320 | } | |
321 | ||
f5eb039d AB |
322 | /* |
323 | * Test whether the ELF file is position independent code (PIC) | |
324 | */ | |
325 | uint8_t lttng_ust_elf_is_pic(struct lttng_ust_elf *elf) | |
326 | { | |
327 | /* | |
328 | * PIC has and e_type value of ET_DYN, see ELF specification | |
329 | * version 1.1 p. 1-3. | |
330 | */ | |
331 | return elf->ehdr->e_type == ET_DYN; | |
332 | } | |
333 | ||
8e2aed3f AB |
334 | /* |
335 | * Destroy the given lttng_ust_elf instance. | |
336 | */ | |
337 | void lttng_ust_elf_destroy(struct lttng_ust_elf *elf) | |
338 | { | |
4fc6ea30 JR |
339 | int ret; |
340 | ||
8e2aed3f AB |
341 | if (!elf) { |
342 | return; | |
343 | } | |
344 | ||
4fc6ea30 JR |
345 | if (elf->fd >= 0) { |
346 | lttng_ust_lock_fd_tracker(); | |
347 | ret = close(elf->fd); | |
348 | if (!ret) { | |
349 | lttng_ust_delete_fd_from_tracker(elf->fd); | |
350 | } else { | |
351 | PERROR("close"); | |
352 | abort(); | |
353 | } | |
354 | lttng_ust_unlock_fd_tracker(); | |
405be658 | 355 | } |
4fc6ea30 JR |
356 | |
357 | free(elf->ehdr); | |
8e2aed3f AB |
358 | free(elf->path); |
359 | free(elf); | |
360 | } | |
361 | ||
362 | /* | |
363 | * Compute the total in-memory size of the ELF file, in bytes. | |
364 | * | |
365 | * Returns 0 if successful, -1 if not. On success, the memory size is | |
366 | * returned through the out parameter `memsz`. | |
367 | */ | |
368 | int lttng_ust_elf_get_memsz(struct lttng_ust_elf *elf, uint64_t *memsz) | |
369 | { | |
370 | uint16_t i; | |
e1f0c569 | 371 | uint64_t low_addr = UINT64_MAX, high_addr = 0; |
8e2aed3f AB |
372 | |
373 | if (!elf || !memsz) { | |
374 | goto error; | |
375 | } | |
376 | ||
377 | for (i = 0; i < elf->ehdr->e_phnum; ++i) { | |
378 | struct lttng_ust_elf_phdr *phdr; | |
8e2aed3f AB |
379 | |
380 | phdr = lttng_ust_elf_get_phdr(elf, i); | |
381 | if (!phdr) { | |
382 | goto error; | |
383 | } | |
384 | ||
385 | /* | |
386 | * Only PT_LOAD segments contribute to memsz. Skip | |
387 | * other segments. | |
388 | */ | |
389 | if (phdr->p_type != PT_LOAD) { | |
390 | goto next_loop; | |
391 | } | |
392 | ||
8886accb MD |
393 | low_addr = min_t(uint64_t, low_addr, phdr->p_vaddr); |
394 | high_addr = max_t(uint64_t, high_addr, | |
395 | phdr->p_vaddr + phdr->p_memsz); | |
8e2aed3f AB |
396 | next_loop: |
397 | free(phdr); | |
398 | } | |
399 | ||
e1f0c569 AB |
400 | if (high_addr < low_addr) { |
401 | /* No PT_LOAD segments or corrupted data. */ | |
402 | goto error; | |
403 | } | |
404 | ||
405 | *memsz = high_addr - low_addr; | |
8e2aed3f AB |
406 | return 0; |
407 | error: | |
408 | return -1; | |
409 | } | |
410 | ||
411 | /* | |
412 | * Internal method used to try and get the build_id from a PT_NOTE | |
413 | * segment ranging from `offset` to `segment_end`. | |
414 | * | |
415 | * If the function returns successfully, the out parameter `found` | |
416 | * indicates whether the build id information was present in the | |
417 | * segment or not. If `found` is not 0, the out parameters `build_id` | |
418 | * and `length` will both have been set with the retrieved | |
419 | * information. | |
420 | * | |
421 | * Returns 0 on success, -1 if an error occurred. | |
422 | */ | |
423 | static | |
424 | int lttng_ust_elf_get_build_id_from_segment( | |
425 | struct lttng_ust_elf *elf, uint8_t **build_id, size_t *length, | |
82ee1ee4 | 426 | off_t offset, off_t segment_end) |
8e2aed3f | 427 | { |
814d07b1 MD |
428 | uint8_t *_build_id = NULL; /* Silence old gcc warning. */ |
429 | size_t _length = 0; /* Silence old gcc warning. */ | |
8e2aed3f AB |
430 | |
431 | while (offset < segment_end) { | |
432 | struct lttng_ust_elf_nhdr nhdr; | |
405be658 | 433 | size_t read_len; |
8e2aed3f AB |
434 | |
435 | /* Align start of note entry */ | |
436 | offset += offset_align(offset, ELF_NOTE_ENTRY_ALIGN); | |
437 | if (offset >= segment_end) { | |
438 | break; | |
439 | } | |
440 | /* | |
441 | * We seek manually because if the note isn't the | |
442 | * build id the data following the header will not | |
443 | * have been read. | |
444 | */ | |
405be658 | 445 | if (lseek(elf->fd, offset, SEEK_SET) < 0) { |
8e2aed3f AB |
446 | goto error; |
447 | } | |
405be658 MD |
448 | if (lttng_ust_read(elf->fd, &nhdr, sizeof(nhdr)) |
449 | < sizeof(nhdr)) { | |
8e2aed3f AB |
450 | goto error; |
451 | } | |
452 | ||
453 | if (!is_elf_native_endian(elf)) { | |
454 | nhdr.n_namesz = bswap_32(nhdr.n_namesz); | |
455 | nhdr.n_descsz = bswap_32(nhdr.n_descsz); | |
456 | nhdr.n_type = bswap_32(nhdr.n_type); | |
457 | } | |
458 | ||
459 | offset += sizeof(nhdr) + nhdr.n_namesz; | |
460 | /* Align start of desc entry */ | |
461 | offset += offset_align(offset, ELF_NOTE_DESC_ALIGN); | |
462 | ||
463 | if (nhdr.n_type != NT_GNU_BUILD_ID) { | |
464 | /* | |
465 | * Ignore non build id notes but still | |
466 | * increase the offset. | |
467 | */ | |
468 | offset += nhdr.n_descsz; | |
469 | continue; | |
470 | } | |
471 | ||
472 | _length = nhdr.n_descsz; | |
473 | _build_id = zmalloc(sizeof(uint8_t) * _length); | |
5ada26b4 | 474 | if (!_build_id) { |
8e2aed3f AB |
475 | goto error; |
476 | } | |
477 | ||
405be658 | 478 | if (lseek(elf->fd, offset, SEEK_SET) < 0) { |
8e2aed3f AB |
479 | goto error; |
480 | } | |
405be658 MD |
481 | read_len = sizeof(*_build_id) * _length; |
482 | if (lttng_ust_read(elf->fd, _build_id, read_len) < read_len) { | |
8e2aed3f AB |
483 | goto error; |
484 | } | |
485 | ||
8e2aed3f AB |
486 | break; |
487 | } | |
488 | ||
82ee1ee4 | 489 | if (_build_id) { |
8e2aed3f AB |
490 | *build_id = _build_id; |
491 | *length = _length; | |
492 | } | |
493 | ||
8e2aed3f AB |
494 | return 0; |
495 | error: | |
83215d66 | 496 | free(_build_id); |
8e2aed3f AB |
497 | return -1; |
498 | } | |
499 | ||
500 | /* | |
501 | * Retrieve a build ID (an array of bytes) from the corresponding | |
502 | * section in the ELF file. The length of the build ID can be either | |
503 | * 16 or 20 bytes depending on the method used to generate it, hence | |
504 | * the length out parameter. | |
505 | * | |
506 | * If the function returns successfully, the out parameter `found` | |
507 | * indicates whether the build id information was present in the ELF | |
508 | * file or not. If `found` is not 0, the out parameters `build_id` and | |
509 | * `length` will both have been set with the retrieved information. | |
510 | * | |
511 | * Returns 0 on success, -1 if an error occurred. | |
512 | */ | |
513 | int lttng_ust_elf_get_build_id(struct lttng_ust_elf *elf, uint8_t **build_id, | |
514 | size_t *length, int *found) | |
515 | { | |
516 | uint16_t i; | |
8c83dbda MD |
517 | uint8_t *_build_id = NULL; /* Silence old gcc warning. */ |
518 | size_t _length = 0; /* Silence old gcc warning. */ | |
8e2aed3f AB |
519 | |
520 | if (!elf || !build_id || !length || !found) { | |
521 | goto error; | |
522 | } | |
523 | ||
524 | for (i = 0; i < elf->ehdr->e_phnum; ++i) { | |
f5a6717a | 525 | off_t offset, segment_end; |
8e2aed3f | 526 | struct lttng_ust_elf_phdr *phdr; |
5b3bbf98 | 527 | int ret = 0; |
8e2aed3f AB |
528 | |
529 | phdr = lttng_ust_elf_get_phdr(elf, i); | |
530 | if (!phdr) { | |
531 | goto error; | |
532 | } | |
533 | ||
534 | /* Build ID will be contained in a PT_NOTE segment. */ | |
535 | if (phdr->p_type != PT_NOTE) { | |
536 | goto next_loop; | |
537 | } | |
538 | ||
539 | offset = phdr->p_offset; | |
540 | segment_end = offset + phdr->p_filesz; | |
541 | ret = lttng_ust_elf_get_build_id_from_segment( | |
82ee1ee4 | 542 | elf, &_build_id, &_length, offset, segment_end); |
8e2aed3f AB |
543 | next_loop: |
544 | free(phdr); | |
545 | if (ret) { | |
546 | goto error; | |
547 | } | |
82ee1ee4 | 548 | if (_build_id) { |
8e2aed3f AB |
549 | break; |
550 | } | |
551 | } | |
552 | ||
82ee1ee4 | 553 | if (_build_id) { |
8e2aed3f AB |
554 | *build_id = _build_id; |
555 | *length = _length; | |
82ee1ee4 AB |
556 | *found = 1; |
557 | } else { | |
558 | *found = 0; | |
8e2aed3f AB |
559 | } |
560 | ||
8e2aed3f AB |
561 | return 0; |
562 | error: | |
99b7132d | 563 | free(_build_id); |
8e2aed3f AB |
564 | return -1; |
565 | } | |
566 | ||
567 | /* | |
568 | * Try to retrieve filename and CRC from given ELF section `shdr`. | |
569 | * | |
570 | * If the function returns successfully, the out parameter `found` | |
571 | * indicates whether the debug link information was present in the ELF | |
572 | * section or not. If `found` is not 0, the out parameters `filename` and | |
573 | * `crc` will both have been set with the retrieved information. | |
574 | * | |
575 | * Returns 0 on success, -1 if an error occurred. | |
576 | */ | |
8e2aed3f AB |
577 | int lttng_ust_elf_get_debug_link_from_section(struct lttng_ust_elf *elf, |
578 | char **filename, uint32_t *crc, | |
8e2aed3f AB |
579 | struct lttng_ust_elf_shdr *shdr) |
580 | { | |
8c83dbda | 581 | char *_filename = NULL; /* Silence old gcc warning. */ |
405be658 | 582 | size_t filename_len; |
8e2aed3f | 583 | char *section_name = NULL; |
8c83dbda | 584 | uint32_t _crc = 0; /* Silence old gcc warning. */ |
8e2aed3f | 585 | |
82ee1ee4 | 586 | if (!elf || !filename || !crc || !shdr) { |
8e2aed3f AB |
587 | goto error; |
588 | } | |
589 | ||
590 | /* | |
591 | * The .gnu_debuglink section is of type SHT_PROGBITS, | |
592 | * skip the other sections. | |
593 | */ | |
594 | if (shdr->sh_type != SHT_PROGBITS) { | |
595 | goto end; | |
596 | } | |
597 | ||
598 | section_name = lttng_ust_elf_get_section_name(elf, | |
599 | shdr->sh_name); | |
600 | if (!section_name) { | |
601 | goto end; | |
602 | } | |
603 | if (strcmp(section_name, ".gnu_debuglink")) { | |
604 | goto end; | |
605 | } | |
606 | ||
607 | /* | |
608 | * The length of the filename is the sh_size excluding the CRC | |
609 | * which comes after it in the section. | |
610 | */ | |
611 | _filename = zmalloc(sizeof(char) * (shdr->sh_size - ELF_CRC_SIZE)); | |
612 | if (!_filename) { | |
613 | goto error; | |
614 | } | |
405be658 | 615 | if (lseek(elf->fd, shdr->sh_offset, SEEK_SET) < 0) { |
8e2aed3f AB |
616 | goto error; |
617 | } | |
405be658 MD |
618 | filename_len = sizeof(*_filename) * (shdr->sh_size - ELF_CRC_SIZE); |
619 | if (lttng_ust_read(elf->fd, _filename, filename_len) < filename_len) { | |
8e2aed3f AB |
620 | goto error; |
621 | } | |
405be658 | 622 | if (lttng_ust_read(elf->fd, &_crc, sizeof(_crc)) < sizeof(_crc)) { |
8e2aed3f AB |
623 | goto error; |
624 | } | |
625 | if (!is_elf_native_endian(elf)) { | |
626 | _crc = bswap_32(_crc); | |
627 | } | |
628 | ||
8e2aed3f AB |
629 | end: |
630 | free(section_name); | |
82ee1ee4 | 631 | if (_filename) { |
8e2aed3f AB |
632 | *filename = _filename; |
633 | *crc = _crc; | |
634 | } | |
8e2aed3f AB |
635 | |
636 | return 0; | |
637 | ||
638 | error: | |
83215d66 MD |
639 | free(_filename); |
640 | free(section_name); | |
8e2aed3f AB |
641 | return -1; |
642 | } | |
643 | ||
644 | /* | |
645 | * Retrieve filename and CRC from ELF's .gnu_debuglink section, if any. | |
646 | * | |
647 | * If the function returns successfully, the out parameter `found` | |
648 | * indicates whether the debug link information was present in the ELF | |
649 | * file or not. If `found` is not 0, the out parameters `filename` and | |
650 | * `crc` will both have been set with the retrieved information. | |
651 | * | |
652 | * Returns 0 on success, -1 if an error occurred. | |
653 | */ | |
654 | int lttng_ust_elf_get_debug_link(struct lttng_ust_elf *elf, char **filename, | |
655 | uint32_t *crc, int *found) | |
656 | { | |
657 | int ret; | |
658 | uint16_t i; | |
8c83dbda MD |
659 | char *_filename = NULL; /* Silence old gcc warning. */ |
660 | uint32_t _crc = 0; /* Silence old gcc warning. */ | |
8e2aed3f AB |
661 | |
662 | if (!elf || !filename || !crc || !found) { | |
663 | goto error; | |
664 | } | |
665 | ||
666 | for (i = 0; i < elf->ehdr->e_shnum; ++i) { | |
667 | struct lttng_ust_elf_shdr *shdr = NULL; | |
668 | ||
669 | shdr = lttng_ust_elf_get_shdr(elf, i); | |
670 | if (!shdr) { | |
671 | goto error; | |
672 | } | |
673 | ||
674 | ret = lttng_ust_elf_get_debug_link_from_section( | |
82ee1ee4 | 675 | elf, &_filename, &_crc, shdr); |
8e2aed3f AB |
676 | free(shdr); |
677 | ||
678 | if (ret) { | |
679 | goto error; | |
680 | } | |
82ee1ee4 | 681 | if (_filename) { |
8e2aed3f AB |
682 | break; |
683 | } | |
684 | } | |
685 | ||
82ee1ee4 | 686 | if (_filename) { |
8e2aed3f AB |
687 | *filename = _filename; |
688 | *crc = _crc; | |
82ee1ee4 AB |
689 | *found = 1; |
690 | } else { | |
691 | *found = 0; | |
8e2aed3f AB |
692 | } |
693 | ||
8e2aed3f | 694 | return 0; |
82ee1ee4 | 695 | |
8e2aed3f | 696 | error: |
99b7132d | 697 | free(_filename); |
8e2aed3f AB |
698 | return -1; |
699 | } |