Commit | Line | Data |
---|---|---|
d0927b41 | 1 | /* |
ab5be9fa MJ |
2 | * Copyright (C) 2015 Antoine Busque <abusque@efficios.com> |
3 | * Copyright (C) 2017 Francis Deslauriers <francis.deslauriers@efficios.com> | |
4 | * Copyright (C) 2017 Erica Bugden <erica.bugden@efficios.com> | |
d0927b41 | 5 | * |
ab5be9fa | 6 | * SPDX-License-Identifier: LGPL-2.1-or-later |
d0927b41 | 7 | * |
d0927b41 FD |
8 | */ |
9 | ||
a6bc4ca9 | 10 | #include <algorithm> |
c9e313bc SM |
11 | #include <common/compat/endian.hpp> |
12 | #include <common/error.hpp> | |
13 | #include <common/lttng-elf.hpp> | |
14 | #include <common/macros.hpp> | |
15 | #include <common/readwrite.hpp> | |
d0927b41 FD |
16 | #include <fcntl.h> |
17 | #include <stdbool.h> | |
18 | #include <stdint.h> | |
19 | #include <stdlib.h> | |
20 | #include <string.h> | |
21 | #include <sys/stat.h> | |
22 | #include <sys/types.h> | |
23 | #include <unistd.h> | |
24 | ||
25 | #include <elf.h> | |
26 | ||
27 | #define BUF_LEN 4096 | |
28 | #define TEXT_SECTION_NAME ".text" | |
29 | #define SYMBOL_TAB_SECTION_NAME ".symtab" | |
30 | #define STRING_TAB_SECTION_NAME ".strtab" | |
ef3dfe5d FD |
31 | #define DYNAMIC_SYMBOL_TAB_SECTION_NAME ".dynsym" |
32 | #define DYNAMIC_STRING_TAB_SECTION_NAME ".dynstr" | |
d0927b41 FD |
33 | #define NOTE_STAPSDT_SECTION_NAME ".note.stapsdt" |
34 | #define NOTE_STAPSDT_NAME "stapsdt" | |
35 | #define NOTE_STAPSDT_TYPE 3 | |
b7e59a88 | 36 | #define MAX_SECTION_DATA_SIZE 512 * 1024 * 1024 |
d0927b41 FD |
37 | |
38 | #if BYTE_ORDER == LITTLE_ENDIAN | |
39 | #define NATIVE_ELF_ENDIANNESS ELFDATA2LSB | |
40 | #else | |
41 | #define NATIVE_ELF_ENDIANNESS ELFDATA2MSB | |
42 | #endif | |
43 | ||
8bd52288 FD |
44 | #define next_4bytes_boundary(x) (typeof(x)) ((((uint64_t)x) + 3) & ~0x03) |
45 | ||
d0927b41 FD |
46 | #define bswap(x) \ |
47 | do { \ | |
48 | switch (sizeof(x)) { \ | |
49 | case 8: \ | |
b1b34226 | 50 | x = be64toh((uint64_t)x); \ |
d0927b41 FD |
51 | break; \ |
52 | case 4: \ | |
b1b34226 | 53 | x = be32toh((uint32_t)x); \ |
d0927b41 FD |
54 | break; \ |
55 | case 2: \ | |
b1b34226 | 56 | x = be16toh((uint16_t)x); \ |
d0927b41 FD |
57 | break; \ |
58 | case 1: \ | |
59 | break; \ | |
60 | default: \ | |
61 | abort(); \ | |
62 | } \ | |
63 | } while (0) | |
64 | ||
65 | #define bswap_shdr(shdr) \ | |
66 | do { \ | |
67 | bswap((shdr).sh_name); \ | |
68 | bswap((shdr).sh_type); \ | |
69 | bswap((shdr).sh_flags); \ | |
70 | bswap((shdr).sh_addr); \ | |
71 | bswap((shdr).sh_offset); \ | |
72 | bswap((shdr).sh_size); \ | |
73 | bswap((shdr).sh_link); \ | |
74 | bswap((shdr).sh_info); \ | |
75 | bswap((shdr).sh_addralign); \ | |
76 | bswap((shdr).sh_entsize); \ | |
77 | } while (0) | |
78 | ||
79 | #define bswap_ehdr(ehdr) \ | |
80 | do { \ | |
81 | bswap((ehdr).e_type); \ | |
82 | bswap((ehdr).e_machine); \ | |
83 | bswap((ehdr).e_version); \ | |
84 | bswap((ehdr).e_entry); \ | |
85 | bswap((ehdr).e_phoff); \ | |
86 | bswap((ehdr).e_shoff); \ | |
87 | bswap((ehdr).e_flags); \ | |
88 | bswap((ehdr).e_ehsize); \ | |
89 | bswap((ehdr).e_phentsize); \ | |
90 | bswap((ehdr).e_phnum); \ | |
91 | bswap((ehdr).e_shentsize); \ | |
92 | bswap((ehdr).e_shnum); \ | |
93 | bswap((ehdr).e_shstrndx); \ | |
94 | } while (0) | |
95 | ||
96 | #define copy_shdr(src_shdr, dst_shdr) \ | |
97 | do { \ | |
98 | (dst_shdr).sh_name = (src_shdr).sh_name; \ | |
99 | (dst_shdr).sh_type = (src_shdr).sh_type; \ | |
100 | (dst_shdr).sh_flags = (src_shdr).sh_flags; \ | |
101 | (dst_shdr).sh_addr = (src_shdr).sh_addr; \ | |
102 | (dst_shdr).sh_offset = (src_shdr).sh_offset; \ | |
103 | (dst_shdr).sh_size = (src_shdr).sh_size; \ | |
104 | (dst_shdr).sh_link = (src_shdr).sh_link; \ | |
105 | (dst_shdr).sh_info = (src_shdr).sh_info; \ | |
106 | (dst_shdr).sh_addralign = (src_shdr).sh_addralign; \ | |
107 | (dst_shdr).sh_entsize = (src_shdr).sh_entsize; \ | |
108 | } while (0) | |
109 | ||
110 | #define copy_ehdr(src_ehdr, dst_ehdr) \ | |
111 | do { \ | |
112 | (dst_ehdr).e_type = (src_ehdr).e_type; \ | |
113 | (dst_ehdr).e_machine = (src_ehdr).e_machine; \ | |
114 | (dst_ehdr).e_version = (src_ehdr).e_version; \ | |
115 | (dst_ehdr).e_entry = (src_ehdr).e_entry; \ | |
116 | (dst_ehdr).e_phoff = (src_ehdr).e_phoff; \ | |
117 | (dst_ehdr).e_shoff = (src_ehdr).e_shoff; \ | |
118 | (dst_ehdr).e_flags = (src_ehdr).e_flags; \ | |
119 | (dst_ehdr).e_ehsize = (src_ehdr).e_ehsize; \ | |
120 | (dst_ehdr).e_phentsize = (src_ehdr).e_phentsize; \ | |
121 | (dst_ehdr).e_phnum = (src_ehdr).e_phnum; \ | |
122 | (dst_ehdr).e_shentsize = (src_ehdr).e_shentsize; \ | |
123 | (dst_ehdr).e_shnum = (src_ehdr).e_shnum; \ | |
124 | (dst_ehdr).e_shstrndx = (src_ehdr).e_shstrndx; \ | |
125 | } while (0) | |
126 | ||
127 | #define copy_sym(src_sym, dst_sym) \ | |
128 | do { \ | |
129 | dst_sym.st_name = src_sym.st_name; \ | |
130 | dst_sym.st_info = src_sym.st_info; \ | |
131 | dst_sym.st_other = src_sym.st_other; \ | |
132 | dst_sym.st_shndx = src_sym.st_shndx; \ | |
133 | dst_sym.st_value = src_sym.st_value; \ | |
134 | dst_sym.st_size = src_sym.st_size; \ | |
135 | } while (0) | |
136 | ||
983a481e MJ |
137 | #ifndef ELFCLASSNUM |
138 | #define ELFCLASSNUM 3 | |
139 | #endif | |
140 | ||
141 | #ifndef ELFDATANUM | |
142 | #define ELFDATANUM 3 | |
143 | #endif | |
144 | ||
145 | #ifndef EV_NUM | |
146 | #define EV_NUM 2 | |
147 | #endif | |
d0927b41 FD |
148 | |
149 | struct lttng_elf_ehdr { | |
150 | uint16_t e_type; | |
151 | uint16_t e_machine; | |
152 | uint32_t e_version; | |
153 | uint64_t e_entry; | |
154 | uint64_t e_phoff; | |
155 | uint64_t e_shoff; | |
156 | uint32_t e_flags; | |
157 | uint16_t e_ehsize; | |
158 | uint16_t e_phentsize; | |
159 | uint16_t e_phnum; | |
160 | uint16_t e_shentsize; | |
161 | uint16_t e_shnum; | |
162 | uint16_t e_shstrndx; | |
163 | }; | |
164 | ||
165 | struct lttng_elf_shdr { | |
166 | uint32_t sh_name; | |
167 | uint32_t sh_type; | |
168 | uint64_t sh_flags; | |
169 | uint64_t sh_addr; | |
170 | uint64_t sh_offset; | |
171 | uint64_t sh_size; | |
172 | uint32_t sh_link; | |
173 | uint32_t sh_info; | |
174 | uint64_t sh_addralign; | |
175 | uint64_t sh_entsize; | |
176 | }; | |
177 | ||
178 | /* | |
179 | * This struct can hold both 32bit and 64bit symbol description. It's used with | |
180 | * the copy_sym() macro. Using this abstraction, we can use the same code for | |
181 | * both bitness. | |
182 | */ | |
183 | struct lttng_elf_sym { | |
184 | uint32_t st_name; | |
185 | uint8_t st_info; | |
186 | uint8_t st_other; | |
187 | uint16_t st_shndx; | |
188 | uint64_t st_value; | |
189 | uint64_t st_size; | |
190 | }; | |
191 | ||
192 | struct lttng_elf { | |
193 | int fd; | |
b7e59a88 | 194 | size_t file_size; |
d0927b41 FD |
195 | uint8_t bitness; |
196 | uint8_t endianness; | |
197 | /* Offset in bytes to start of section names string table. */ | |
198 | off_t section_names_offset; | |
199 | /* Size in bytes of section names string table. */ | |
200 | size_t section_names_size; | |
201 | struct lttng_elf_ehdr *ehdr; | |
202 | }; | |
203 | ||
204 | static inline | |
205 | int is_elf_32_bit(struct lttng_elf *elf) | |
206 | { | |
207 | return elf->bitness == ELFCLASS32; | |
208 | } | |
209 | ||
210 | static inline | |
211 | int is_elf_native_endian(struct lttng_elf *elf) | |
212 | { | |
213 | return elf->endianness == NATIVE_ELF_ENDIANNESS; | |
214 | } | |
215 | ||
216 | static | |
217 | int populate_section_header(struct lttng_elf * elf, struct lttng_elf_shdr *shdr, | |
218 | uint32_t index) | |
219 | { | |
220 | int ret = 0; | |
221 | off_t offset; | |
222 | ||
223 | /* Compute the offset of the section in the file */ | |
224 | offset = (off_t) elf->ehdr->e_shoff | |
225 | + (off_t) index * elf->ehdr->e_shentsize; | |
226 | ||
227 | if (lseek(elf->fd, offset, SEEK_SET) < 0) { | |
228 | PERROR("Error seeking to the beginning of ELF section header"); | |
229 | ret = -1; | |
230 | goto error; | |
231 | } | |
232 | ||
233 | if (is_elf_32_bit(elf)) { | |
234 | Elf32_Shdr elf_shdr; | |
235 | ||
236 | if (lttng_read(elf->fd, &elf_shdr, sizeof(elf_shdr)) < sizeof(elf_shdr)) { | |
237 | PERROR("Error reading ELF section header"); | |
238 | ret = -1; | |
239 | goto error; | |
240 | } | |
241 | if (!is_elf_native_endian(elf)) { | |
242 | bswap_shdr(elf_shdr); | |
243 | } | |
244 | copy_shdr(elf_shdr, *shdr); | |
245 | } else { | |
246 | Elf64_Shdr elf_shdr; | |
247 | ||
248 | if (lttng_read(elf->fd, &elf_shdr, sizeof(elf_shdr)) < sizeof(elf_shdr)) { | |
249 | PERROR("Error reading ELF section header"); | |
250 | ret = -1; | |
251 | goto error; | |
252 | } | |
253 | if (!is_elf_native_endian(elf)) { | |
254 | bswap_shdr(elf_shdr); | |
255 | } | |
256 | copy_shdr(elf_shdr, *shdr); | |
257 | } | |
258 | ||
259 | error: | |
260 | return ret; | |
261 | } | |
262 | ||
263 | static | |
264 | int populate_elf_header(struct lttng_elf *elf) | |
265 | { | |
266 | int ret = 0; | |
267 | ||
268 | /* | |
269 | * Move the read pointer back to the beginning to read the full header | |
270 | * and copy it in our structure. | |
271 | */ | |
272 | if (lseek(elf->fd, 0, SEEK_SET) < 0) { | |
273 | PERROR("Error seeking to the beginning of the file"); | |
274 | ret = -1; | |
275 | goto error; | |
276 | } | |
277 | ||
278 | /* | |
279 | * Use macros to set fields in the ELF header struct for both 32bit and | |
280 | * 64bit. | |
281 | */ | |
282 | if (is_elf_32_bit(elf)) { | |
283 | Elf32_Ehdr elf_ehdr; | |
284 | ||
285 | if (lttng_read(elf->fd, &elf_ehdr, sizeof(elf_ehdr)) < sizeof(elf_ehdr)) { | |
286 | ret = -1; | |
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 | ||
296 | if (lttng_read(elf->fd, &elf_ehdr, sizeof(elf_ehdr)) < sizeof(elf_ehdr)) { | |
297 | ret = -1; | |
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 | error: | |
306 | return ret; | |
307 | } | |
308 | ||
309 | /* | |
310 | * Retrieve the nth (where n is the `index` argument) shdr (section | |
311 | * header) from the given elf instance. | |
312 | * | |
22fae25a | 313 | * 0 is returned on succes, -1 on failure. |
d0927b41 FD |
314 | */ |
315 | static | |
22fae25a JG |
316 | int lttng_elf_get_section_hdr(struct lttng_elf *elf, |
317 | uint16_t index, struct lttng_elf_shdr *out_header) | |
d0927b41 | 318 | { |
d0927b41 FD |
319 | int ret = 0; |
320 | ||
321 | if (!elf) { | |
22fae25a | 322 | ret = -1; |
d0927b41 FD |
323 | goto error; |
324 | } | |
325 | ||
326 | if (index >= elf->ehdr->e_shnum) { | |
22fae25a | 327 | ret = -1; |
d0927b41 FD |
328 | goto error; |
329 | } | |
330 | ||
22fae25a | 331 | ret = populate_section_header(elf, out_header, index); |
d0927b41 | 332 | if (ret) { |
d0927b41 FD |
333 | DBG("Error populating section header."); |
334 | goto error; | |
335 | } | |
d0927b41 FD |
336 | |
337 | error: | |
22fae25a | 338 | return ret; |
d0927b41 FD |
339 | } |
340 | ||
341 | /* | |
342 | * Lookup a section's name from a given offset (usually from an shdr's | |
343 | * sh_name value) in bytes relative to the beginning of the section | |
344 | * names string table. | |
345 | * | |
346 | * If no name is found, NULL is returned. | |
347 | */ | |
348 | static | |
349 | char *lttng_elf_get_section_name(struct lttng_elf *elf, off_t offset) | |
350 | { | |
351 | char *name = NULL; | |
352 | size_t name_length = 0, to_read; /* name_length does not include \0 */ | |
353 | ||
354 | if (!elf) { | |
355 | goto error; | |
356 | } | |
357 | ||
358 | if (offset >= elf->section_names_size) { | |
359 | goto error; | |
360 | } | |
361 | ||
362 | if (lseek(elf->fd, elf->section_names_offset + offset, SEEK_SET) < 0) { | |
363 | PERROR("Error seeking to the beginning of ELF string table section"); | |
364 | goto error; | |
365 | } | |
366 | ||
367 | to_read = elf->section_names_size - offset; | |
368 | ||
369 | /* Find first \0 after or at current location, remember name_length. */ | |
370 | for (;;) { | |
371 | char buf[BUF_LEN]; | |
372 | ssize_t read_len; | |
373 | size_t i; | |
374 | ||
375 | if (!to_read) { | |
376 | goto error; | |
377 | } | |
a6bc4ca9 | 378 | read_len = lttng_read(elf->fd, buf, std::min<size_t>(BUF_LEN, to_read)); |
d0927b41 FD |
379 | if (read_len <= 0) { |
380 | PERROR("Error reading ELF string table section"); | |
381 | goto error; | |
382 | } | |
383 | for (i = 0; i < read_len; i++) { | |
384 | if (buf[i] == '\0') { | |
385 | name_length += i; | |
386 | goto end; | |
387 | } | |
388 | } | |
389 | name_length += read_len; | |
390 | to_read -= read_len; | |
391 | } | |
392 | end: | |
393 | /* | |
394 | * We found the length of the section name, now seek back to the | |
395 | * beginning of the name and copy it in the newly allocated buffer. | |
396 | */ | |
64803277 | 397 | name = calloc<char>((name_length + 1)); /* + 1 for \0 */ |
d0927b41 FD |
398 | if (!name) { |
399 | PERROR("Error allocating ELF section name buffer"); | |
400 | goto error; | |
401 | } | |
402 | if (lseek(elf->fd, elf->section_names_offset + offset, SEEK_SET) < 0) { | |
403 | PERROR("Error seeking to the offset of the ELF section name"); | |
404 | goto error; | |
405 | } | |
406 | if (lttng_read(elf->fd, name, name_length + 1) < name_length + 1) { | |
407 | PERROR("Error reading the ELF section name"); | |
408 | goto error; | |
409 | } | |
410 | ||
411 | return name; | |
412 | ||
413 | error: | |
414 | free(name); | |
415 | return NULL; | |
416 | } | |
417 | ||
418 | static | |
419 | int lttng_elf_validate_and_populate(struct lttng_elf *elf) | |
420 | { | |
421 | uint8_t version; | |
422 | uint8_t e_ident[EI_NIDENT]; | |
423 | uint8_t *magic_number = NULL; | |
424 | int ret = 0; | |
425 | ||
426 | if (elf->fd == -1) { | |
427 | DBG("fd error"); | |
428 | ret = LTTNG_ERR_ELF_PARSING; | |
429 | goto end; | |
430 | } | |
431 | ||
432 | /* | |
433 | * First read the magic number, endianness and version to later populate | |
434 | * the ELF header with the correct endianness and bitness. | |
435 | * (see elf.h) | |
436 | */ | |
437 | ||
438 | if (lseek(elf->fd, 0, SEEK_SET) < 0) { | |
439 | PERROR("Error seeking the beginning of ELF file"); | |
440 | ret = LTTNG_ERR_ELF_PARSING; | |
441 | goto end; | |
442 | } | |
443 | ret = lttng_read(elf->fd, e_ident, EI_NIDENT); | |
444 | if (ret < EI_NIDENT) { | |
445 | DBG("Error reading the ELF identification fields"); | |
446 | if (ret == -1) { | |
447 | PERROR("Error reading the ELF identification fields"); | |
448 | } | |
449 | ret = LTTNG_ERR_ELF_PARSING; | |
450 | goto end; | |
451 | } | |
452 | ||
453 | /* | |
454 | * Copy fields used to check that the target file is in fact a valid ELF | |
455 | * file. | |
456 | */ | |
457 | elf->bitness = e_ident[EI_CLASS]; | |
458 | elf->endianness = e_ident[EI_DATA]; | |
459 | version = e_ident[EI_VERSION]; | |
460 | magic_number = &e_ident[EI_MAG0]; | |
461 | ||
462 | /* | |
463 | * Check the magic number. | |
464 | */ | |
465 | if (memcmp(magic_number, ELFMAG, SELFMAG) != 0) { | |
466 | DBG("Error check ELF magic number."); | |
467 | ret = LTTNG_ERR_ELF_PARSING; | |
468 | goto end; | |
469 | } | |
470 | ||
471 | /* | |
472 | * Check the bitness is either ELFCLASS32 or ELFCLASS64. | |
473 | */ | |
474 | if (elf->bitness <= ELFCLASSNONE || elf->bitness >= ELFCLASSNUM) { | |
475 | DBG("ELF class error."); | |
476 | ret = LTTNG_ERR_ELF_PARSING; | |
477 | goto end; | |
478 | } | |
479 | ||
480 | /* | |
481 | * Check the endianness is either ELFDATA2LSB or ELFDATA2MSB. | |
482 | */ | |
483 | if (elf->endianness <= ELFDATANONE || elf->endianness >= ELFDATANUM) { | |
484 | DBG("ELF endianness error."); | |
485 | ret = LTTNG_ERR_ELF_PARSING; | |
486 | goto end; | |
487 | } | |
488 | ||
489 | /* | |
490 | * Check the version is ELF_CURRENT. | |
491 | */ | |
492 | if (version <= EV_NONE || version >= EV_NUM) { | |
493 | DBG("Wrong ELF version."); | |
494 | ret = LTTNG_ERR_ELF_PARSING; | |
495 | goto end; | |
496 | } | |
497 | ||
64803277 | 498 | elf->ehdr = zmalloc<lttng_elf_ehdr>(); |
d0927b41 FD |
499 | if (!elf->ehdr) { |
500 | PERROR("Error allocation buffer for ELF header"); | |
501 | ret = LTTNG_ERR_NOMEM; | |
502 | goto end; | |
503 | } | |
504 | ||
505 | /* | |
506 | * Copy the content of the elf header. | |
507 | */ | |
508 | ret = populate_elf_header(elf); | |
509 | if (ret) { | |
510 | DBG("Error reading ELF header,"); | |
511 | goto free_elf_error; | |
512 | } | |
513 | ||
514 | goto end; | |
515 | ||
516 | free_elf_error: | |
517 | free(elf->ehdr); | |
518 | elf->ehdr = NULL; | |
519 | end: | |
520 | return ret; | |
521 | } | |
522 | ||
523 | /* | |
524 | * Create an instance of lttng_elf for the ELF file located at | |
525 | * `path`. | |
526 | * | |
527 | * Return a pointer to the instance on success, NULL on failure. | |
528 | */ | |
529 | static | |
530 | struct lttng_elf *lttng_elf_create(int fd) | |
531 | { | |
22fae25a | 532 | struct lttng_elf_shdr section_names_shdr; |
d0927b41 FD |
533 | struct lttng_elf *elf = NULL; |
534 | int ret; | |
b7e59a88 | 535 | struct stat stat_buf; |
d0927b41 FD |
536 | |
537 | if (fd < 0) { | |
538 | goto error; | |
539 | } | |
540 | ||
b7e59a88 JG |
541 | ret = fstat(fd, &stat_buf); |
542 | if (ret) { | |
543 | PERROR("Failed to determine size of elf file"); | |
544 | goto error; | |
545 | } | |
546 | if (!S_ISREG(stat_buf.st_mode)) { | |
547 | ERR("Refusing to initialize lttng_elf from non-regular file"); | |
548 | goto error; | |
549 | } | |
550 | ||
64803277 | 551 | elf = zmalloc<lttng_elf>(); |
d0927b41 FD |
552 | if (!elf) { |
553 | PERROR("Error allocating struct lttng_elf"); | |
554 | goto error; | |
555 | } | |
b7e59a88 | 556 | elf->file_size = (size_t) stat_buf.st_size; |
d0927b41 FD |
557 | |
558 | elf->fd = dup(fd); | |
559 | if (elf->fd < 0) { | |
560 | PERROR("Error duplicating file descriptor to binary"); | |
561 | goto error; | |
562 | } | |
563 | ||
564 | ret = lttng_elf_validate_and_populate(elf); | |
565 | if (ret) { | |
566 | goto error; | |
567 | } | |
568 | ||
22fae25a JG |
569 | ret = lttng_elf_get_section_hdr( |
570 | elf, elf->ehdr->e_shstrndx, §ion_names_shdr); | |
571 | if (ret) { | |
d0927b41 FD |
572 | goto error; |
573 | } | |
574 | ||
22fae25a JG |
575 | elf->section_names_offset = section_names_shdr.sh_offset; |
576 | elf->section_names_size = section_names_shdr.sh_size; | |
d0927b41 FD |
577 | return elf; |
578 | ||
579 | error: | |
580 | if (elf) { | |
581 | if (elf->ehdr) { | |
582 | free(elf->ehdr); | |
583 | } | |
584 | if (elf->fd >= 0) { | |
585 | if (close(elf->fd)) { | |
586 | PERROR("Error closing file descriptor in error path"); | |
587 | abort(); | |
588 | } | |
589 | } | |
590 | free(elf); | |
591 | } | |
592 | return NULL; | |
593 | } | |
594 | ||
595 | /* | |
596 | * Destroy the given lttng_elf instance. | |
597 | */ | |
598 | static | |
599 | void lttng_elf_destroy(struct lttng_elf *elf) | |
600 | { | |
601 | if (!elf) { | |
602 | return; | |
603 | } | |
604 | ||
605 | free(elf->ehdr); | |
606 | if (close(elf->fd)) { | |
607 | PERROR("Error closing file description in error path"); | |
608 | abort(); | |
609 | } | |
610 | free(elf); | |
611 | } | |
612 | ||
613 | static | |
614 | int lttng_elf_get_section_hdr_by_name(struct lttng_elf *elf, | |
22fae25a | 615 | const char *section_name, struct lttng_elf_shdr *section_hdr) |
d0927b41 FD |
616 | { |
617 | int i; | |
618 | char *curr_section_name; | |
22fae25a | 619 | |
d0927b41 | 620 | for (i = 0; i < elf->ehdr->e_shnum; ++i) { |
4e0b99ca | 621 | bool name_equal; |
22fae25a | 622 | int ret = lttng_elf_get_section_hdr(elf, i, section_hdr); |
d0927b41 | 623 | |
22fae25a JG |
624 | if (ret) { |
625 | break; | |
626 | } | |
627 | curr_section_name = lttng_elf_get_section_name(elf, | |
628 | section_hdr->sh_name); | |
d0927b41 FD |
629 | if (!curr_section_name) { |
630 | continue; | |
631 | } | |
4e0b99ca JG |
632 | name_equal = strcmp(curr_section_name, section_name) == 0; |
633 | free(curr_section_name); | |
634 | if (name_equal) { | |
d0927b41 FD |
635 | return 0; |
636 | } | |
637 | } | |
638 | return LTTNG_ERR_ELF_PARSING; | |
639 | } | |
640 | ||
641 | static | |
642 | char *lttng_elf_get_section_data(struct lttng_elf *elf, | |
643 | struct lttng_elf_shdr *shdr) | |
644 | { | |
645 | int ret; | |
646 | off_t section_offset; | |
647 | char *data; | |
ee5b998f | 648 | size_t max_alloc_size; |
d0927b41 FD |
649 | |
650 | if (!elf || !shdr) { | |
651 | goto error; | |
652 | } | |
653 | ||
a6bc4ca9 | 654 | max_alloc_size = std::min<size_t>(MAX_SECTION_DATA_SIZE, elf->file_size); |
ee5b998f | 655 | |
d0927b41 FD |
656 | section_offset = shdr->sh_offset; |
657 | if (lseek(elf->fd, section_offset, SEEK_SET) < 0) { | |
658 | PERROR("Error seeking to section offset"); | |
659 | goto error; | |
660 | } | |
661 | ||
b7e59a88 JG |
662 | if (shdr->sh_size > max_alloc_size) { |
663 | ERR("ELF section size exceeds maximal allowed size of %zu bytes", | |
664 | max_alloc_size); | |
665 | goto error; | |
666 | } | |
64803277 | 667 | data = calloc<char>(shdr->sh_size); |
d0927b41 FD |
668 | if (!data) { |
669 | PERROR("Error allocating buffer for ELF section data"); | |
670 | goto error; | |
671 | } | |
672 | ret = lttng_read(elf->fd, data, shdr->sh_size); | |
673 | if (ret == -1) { | |
674 | PERROR("Error reading ELF section data"); | |
675 | goto free_error; | |
676 | } | |
677 | ||
678 | return data; | |
679 | ||
680 | free_error: | |
681 | free(data); | |
682 | error: | |
683 | return NULL; | |
684 | } | |
685 | ||
686 | /* | |
687 | * Convert the virtual address in a binary's mapping to the offset of | |
688 | * the corresponding instruction in the binary file. | |
689 | * This function assumes the address is in the text section. | |
690 | * | |
691 | * Returns the offset on success or non-zero in case of failure. | |
692 | */ | |
693 | static | |
694 | int lttng_elf_convert_addr_in_text_to_offset(struct lttng_elf *elf_handle, | |
695 | size_t addr, uint64_t *offset) | |
696 | { | |
697 | int ret = 0; | |
698 | off_t text_section_offset; | |
699 | off_t text_section_addr_beg; | |
700 | off_t text_section_addr_end; | |
701 | off_t offset_in_section; | |
22fae25a | 702 | struct lttng_elf_shdr text_section_hdr; |
d0927b41 FD |
703 | |
704 | if (!elf_handle) { | |
705 | DBG("Invalid ELF handle."); | |
706 | ret = LTTNG_ERR_ELF_PARSING; | |
707 | goto error; | |
708 | } | |
709 | ||
710 | /* Get a pointer to the .text section header. */ | |
711 | ret = lttng_elf_get_section_hdr_by_name(elf_handle, | |
712 | TEXT_SECTION_NAME, &text_section_hdr); | |
713 | if (ret) { | |
714 | DBG("Text section not found in binary."); | |
715 | ret = LTTNG_ERR_ELF_PARSING; | |
716 | goto error; | |
717 | } | |
718 | ||
22fae25a JG |
719 | text_section_offset = text_section_hdr.sh_offset; |
720 | text_section_addr_beg = text_section_hdr.sh_addr; | |
721 | text_section_addr_end = | |
722 | text_section_addr_beg + text_section_hdr.sh_size; | |
d0927b41 FD |
723 | |
724 | /* | |
725 | * Verify that the address is within the .text section boundaries. | |
726 | */ | |
727 | if (addr < text_section_addr_beg || addr > text_section_addr_end) { | |
728 | DBG("Address found is outside of the .text section addr=0x%zx, " | |
729 | ".text section=[0x%jd - 0x%jd].", addr, (intmax_t)text_section_addr_beg, | |
730 | (intmax_t)text_section_addr_end); | |
731 | ret = LTTNG_ERR_ELF_PARSING; | |
732 | goto error; | |
733 | } | |
734 | ||
735 | offset_in_section = addr - text_section_addr_beg; | |
736 | ||
737 | /* | |
738 | * Add the target offset in the text section to the offset of this text | |
739 | * section from the beginning of the binary file. | |
740 | */ | |
741 | *offset = text_section_offset + offset_in_section; | |
742 | ||
743 | error: | |
744 | return ret; | |
745 | } | |
746 | ||
747 | /* | |
748 | * Compute the offset of a symbol from the begining of the ELF binary. | |
749 | * | |
750 | * On success, returns 0 offset parameter is set to the computed value | |
751 | * On failure, returns -1. | |
752 | */ | |
753 | int lttng_elf_get_symbol_offset(int fd, char *symbol, uint64_t *offset) | |
754 | { | |
755 | int ret = 0; | |
756 | int sym_found = 0; | |
757 | int sym_count = 0; | |
758 | int sym_idx = 0; | |
759 | uint64_t addr = 0; | |
760 | char *curr_sym_str = NULL; | |
761 | char *symbol_table_data = NULL; | |
762 | char *string_table_data = NULL; | |
b53d4e59 | 763 | const char *string_table_name = NULL; |
22fae25a JG |
764 | struct lttng_elf_shdr symtab_hdr; |
765 | struct lttng_elf_shdr strtab_hdr; | |
d0927b41 FD |
766 | struct lttng_elf *elf = NULL; |
767 | ||
768 | if (!symbol || !offset ) { | |
769 | ret = LTTNG_ERR_ELF_PARSING; | |
770 | goto end; | |
771 | } | |
772 | ||
773 | elf = lttng_elf_create(fd); | |
774 | if (!elf) { | |
775 | ret = LTTNG_ERR_ELF_PARSING; | |
776 | goto end; | |
777 | } | |
778 | ||
ef3dfe5d FD |
779 | /* |
780 | * The .symtab section might not exist on stripped binaries. | |
781 | * Try to get the symbol table section header first. If it's absent, | |
782 | * try to get the dynamic symbol table. All symbols in the dynamic | |
783 | * symbol tab are in the (normal) symbol table if it exists. | |
784 | */ | |
d0927b41 FD |
785 | ret = lttng_elf_get_section_hdr_by_name(elf, SYMBOL_TAB_SECTION_NAME, |
786 | &symtab_hdr); | |
787 | if (ret) { | |
ef3dfe5d FD |
788 | DBG("Cannot get ELF Symbol Table section. Trying to get ELF Dynamic Symbol Table section."); |
789 | /* Get the dynamic symbol table section header. */ | |
790 | ret = lttng_elf_get_section_hdr_by_name(elf, DYNAMIC_SYMBOL_TAB_SECTION_NAME, | |
791 | &symtab_hdr); | |
792 | if (ret) { | |
793 | DBG("Cannot get ELF Symbol Table nor Dynamic Symbol Table sections."); | |
794 | ret = LTTNG_ERR_ELF_PARSING; | |
795 | goto destroy_elf; | |
796 | } | |
797 | string_table_name = DYNAMIC_STRING_TAB_SECTION_NAME; | |
798 | } else { | |
799 | string_table_name = STRING_TAB_SECTION_NAME; | |
d0927b41 | 800 | } |
ef3dfe5d | 801 | |
d0927b41 | 802 | /* Get the data associated with the symbol table section. */ |
22fae25a | 803 | symbol_table_data = lttng_elf_get_section_data(elf, &symtab_hdr); |
d0927b41 FD |
804 | if (symbol_table_data == NULL) { |
805 | DBG("Cannot get ELF Symbol Table data."); | |
806 | ret = LTTNG_ERR_ELF_PARSING; | |
807 | goto destroy_elf; | |
808 | } | |
809 | ||
810 | /* Get the string table section header. */ | |
ef3dfe5d | 811 | ret = lttng_elf_get_section_hdr_by_name(elf, string_table_name, |
d0927b41 FD |
812 | &strtab_hdr); |
813 | if (ret) { | |
814 | DBG("Cannot get ELF string table section."); | |
815 | goto free_symbol_table_data; | |
816 | } | |
817 | ||
818 | /* Get the data associated with the string table section. */ | |
22fae25a | 819 | string_table_data = lttng_elf_get_section_data(elf, &strtab_hdr); |
d0927b41 FD |
820 | if (string_table_data == NULL) { |
821 | DBG("Cannot get ELF string table section data."); | |
822 | ret = LTTNG_ERR_ELF_PARSING; | |
823 | goto free_symbol_table_data; | |
824 | } | |
825 | ||
826 | /* Get the number of symbol in the table for the iteration. */ | |
a395e079 JG |
827 | if (symtab_hdr.sh_entsize == 0) { |
828 | DBG("Invalid ELF string table entry size."); | |
829 | ret = LTTNG_ERR_ELF_PARSING; | |
3308655a | 830 | goto free_string_table_data; |
a395e079 JG |
831 | } |
832 | ||
22fae25a | 833 | sym_count = symtab_hdr.sh_size / symtab_hdr.sh_entsize; |
d0927b41 FD |
834 | |
835 | /* Loop over all symbol. */ | |
836 | for (sym_idx = 0; sym_idx < sym_count; sym_idx++) { | |
837 | struct lttng_elf_sym curr_sym; | |
838 | ||
839 | /* Get the symbol at the current index. */ | |
840 | if (is_elf_32_bit(elf)) { | |
841 | Elf32_Sym tmp = ((Elf32_Sym *) symbol_table_data)[sym_idx]; | |
842 | copy_sym(tmp, curr_sym); | |
843 | } else { | |
844 | Elf64_Sym tmp = ((Elf64_Sym *) symbol_table_data)[sym_idx]; | |
845 | copy_sym(tmp, curr_sym); | |
846 | } | |
847 | ||
848 | /* | |
849 | * If the st_name field is zero, there is no string name for | |
850 | * this symbol; skip to the next symbol. | |
851 | */ | |
852 | if (curr_sym.st_name == 0) { | |
853 | continue; | |
854 | } | |
855 | ||
856 | /* | |
857 | * Use the st_name field in the lttng_elf_sym struct to get offset of | |
858 | * the symbol's name from the beginning of the string table. | |
859 | */ | |
860 | curr_sym_str = string_table_data + curr_sym.st_name; | |
861 | ||
862 | /* | |
863 | * If the current symbol is not a function; skip to the next symbol. | |
864 | */ | |
983a481e MJ |
865 | /* Both 32bit and 64bit use the same 1 byte field for type. (See elf.h) */ |
866 | if (ELF32_ST_TYPE(curr_sym.st_info) != STT_FUNC) { | |
d0927b41 FD |
867 | continue; |
868 | } | |
869 | ||
870 | /* | |
871 | * Compare with the search symbol. If there is a match set the address | |
872 | * output parameter and return success. | |
873 | */ | |
874 | if (strcmp(symbol, curr_sym_str) == 0 ) { | |
875 | sym_found = 1; | |
876 | addr = curr_sym.st_value; | |
877 | break; | |
878 | } | |
879 | } | |
880 | ||
881 | if (!sym_found) { | |
882 | DBG("Symbol not found."); | |
883 | ret = LTTNG_ERR_ELF_PARSING; | |
884 | goto free_string_table_data; | |
885 | } | |
886 | ||
887 | /* | |
888 | * Use the virtual address of the symbol to compute the offset of this | |
889 | * symbol from the beginning of the executable file. | |
890 | */ | |
891 | ret = lttng_elf_convert_addr_in_text_to_offset(elf, addr, offset); | |
892 | if (ret) { | |
512df046 | 893 | DBG("Cannot convert addr to offset."); |
d0927b41 FD |
894 | goto free_string_table_data; |
895 | } | |
896 | ||
897 | ||
898 | free_string_table_data: | |
899 | free(string_table_data); | |
900 | free_symbol_table_data: | |
901 | free(symbol_table_data); | |
902 | destroy_elf: | |
903 | lttng_elf_destroy(elf); | |
904 | end: | |
905 | return ret; | |
906 | } | |
8bd52288 FD |
907 | |
908 | /* | |
909 | * Compute the offsets of SDT probes from the begining of the ELF binary. | |
910 | * | |
911 | * On success, returns 0 and the nb_probes parameter is set to the number of | |
912 | * offsets found and the offsets parameter points to an array of offsets where | |
913 | * the SDT probes are. | |
914 | * On failure, returns -1. | |
915 | */ | |
916 | int lttng_elf_get_sdt_probe_offsets(int fd, const char *provider_name, | |
917 | const char *probe_name, uint64_t **offsets, uint32_t *nb_probes) | |
918 | { | |
919 | int ret = 0, nb_match = 0; | |
22fae25a | 920 | struct lttng_elf_shdr stap_note_section_hdr; |
8bd52288 FD |
921 | struct lttng_elf *elf = NULL; |
922 | char *stap_note_section_data = NULL; | |
923 | char *curr_note_section_begin, *curr_data_ptr, *curr_probe, *curr_provider; | |
d3be5495 | 924 | char *next_note_ptr; |
8bd52288 FD |
925 | uint32_t name_size, desc_size, note_type; |
926 | uint64_t curr_probe_location, curr_probe_offset, curr_semaphore_location; | |
927 | uint64_t *probe_locs = NULL, *new_probe_locs = NULL; | |
928 | ||
929 | if (!provider_name || !probe_name || !nb_probes || !offsets) { | |
930 | DBG("Invalid arguments."); | |
931 | ret = LTTNG_ERR_ELF_PARSING; | |
932 | goto error; | |
933 | } | |
934 | ||
935 | elf = lttng_elf_create(fd); | |
936 | if (!elf) { | |
937 | DBG("Error allocation ELF."); | |
938 | ret = LTTNG_ERR_ELF_PARSING; | |
939 | goto error; | |
940 | } | |
941 | ||
942 | /* Get the stap note section header. */ | |
943 | ret = lttng_elf_get_section_hdr_by_name(elf, NOTE_STAPSDT_SECTION_NAME, | |
944 | &stap_note_section_hdr); | |
945 | if (ret) { | |
946 | DBG("Cannot get ELF stap note section."); | |
947 | goto destroy_elf_error; | |
948 | } | |
949 | ||
950 | /* Get the data associated with the stap note section. */ | |
22fae25a JG |
951 | stap_note_section_data = |
952 | lttng_elf_get_section_data(elf, &stap_note_section_hdr); | |
8bd52288 FD |
953 | if (stap_note_section_data == NULL) { |
954 | DBG("Cannot get ELF stap note section data."); | |
955 | ret = LTTNG_ERR_ELF_PARSING; | |
956 | goto destroy_elf_error; | |
957 | } | |
958 | ||
8bd52288 FD |
959 | next_note_ptr = stap_note_section_data; |
960 | curr_note_section_begin = stap_note_section_data; | |
961 | ||
962 | *offsets = NULL; | |
963 | while (1) { | |
964 | curr_data_ptr = next_note_ptr; | |
965 | /* Check if we have reached the end of the note section. */ | |
966 | if (curr_data_ptr >= | |
22fae25a JG |
967 | curr_note_section_begin + |
968 | stap_note_section_hdr.sh_size) { | |
8bd52288 FD |
969 | *nb_probes = nb_match; |
970 | *offsets = probe_locs; | |
971 | ret = 0; | |
972 | break; | |
973 | } | |
974 | /* Get name size field. */ | |
975 | name_size = next_4bytes_boundary(*(uint32_t*) curr_data_ptr); | |
976 | curr_data_ptr += sizeof(uint32_t); | |
977 | ||
978 | /* Sanity check; a zero name_size is reserved. */ | |
979 | if (name_size == 0) { | |
980 | DBG("Invalid name size field in SDT probe descriptions" | |
981 | "section."); | |
982 | ret = -1; | |
983 | goto realloc_error; | |
984 | } | |
985 | ||
986 | /* Get description size field. */ | |
987 | desc_size = next_4bytes_boundary(*(uint32_t*) curr_data_ptr); | |
988 | curr_data_ptr += sizeof(uint32_t); | |
989 | ||
990 | /* Get type field. */ | |
991 | note_type = *(uint32_t *) curr_data_ptr; | |
992 | curr_data_ptr += sizeof(uint32_t); | |
993 | ||
994 | /* | |
995 | * Move the pointer to the next note to be ready for the next | |
996 | * iteration. The current note is made of 3 unsigned 32bit | |
997 | * integers (name size, descriptor size and note type), the | |
998 | * name and the descriptor. To move to the next note, we move | |
999 | * the pointer according to those values. | |
1000 | */ | |
1001 | next_note_ptr = next_note_ptr + | |
1002 | (3 * sizeof(uint32_t)) + desc_size + name_size; | |
1003 | ||
1004 | /* | |
1005 | * Move ptr to the end of the name string (we don't need it) | |
1006 | * and go to the next 4 byte alignement. | |
1007 | */ | |
1008 | if (note_type != NOTE_STAPSDT_TYPE || | |
1009 | strncmp(curr_data_ptr, NOTE_STAPSDT_NAME, name_size) != 0) { | |
1010 | continue; | |
1011 | } | |
1012 | ||
1013 | curr_data_ptr += name_size; | |
1014 | ||
8bd52288 FD |
1015 | /* Get probe location. */ |
1016 | curr_probe_location = *(uint64_t *) curr_data_ptr; | |
1017 | curr_data_ptr += sizeof(uint64_t); | |
1018 | ||
1019 | /* Pass over the base. Not needed. */ | |
1020 | curr_data_ptr += sizeof(uint64_t); | |
1021 | ||
1022 | /* Get semaphore location. */ | |
1023 | curr_semaphore_location = *(uint64_t *) curr_data_ptr; | |
1024 | curr_data_ptr += sizeof(uint64_t); | |
1025 | /* Get provider name. */ | |
1026 | curr_provider = curr_data_ptr; | |
1027 | curr_data_ptr += strlen(curr_provider) + 1; | |
1028 | ||
1029 | /* Get probe name. */ | |
1030 | curr_probe = curr_data_ptr; | |
8bd52288 FD |
1031 | |
1032 | /* Check if the provider and probe name match */ | |
1033 | if (strcmp(provider_name, curr_provider) == 0 && | |
1034 | strcmp(probe_name, curr_probe) == 0) { | |
1035 | int new_size; | |
1036 | ||
1037 | /* | |
1038 | * We currently don't support SDT probes with semaphores. Return | |
1039 | * success as we found a matching probe but it's guarded by a | |
1040 | * semaphore. | |
1041 | */ | |
1042 | if (curr_semaphore_location != 0) { | |
1043 | ret = LTTNG_ERR_SDT_PROBE_SEMAPHORE; | |
09f3038c | 1044 | goto realloc_error; |
8bd52288 FD |
1045 | } |
1046 | ||
1047 | new_size = (++nb_match) * sizeof(uint64_t); | |
1048 | ||
1049 | /* | |
1050 | * Found a match with not semaphore, we need to copy the | |
1051 | * probe_location to the output parameter. | |
1052 | */ | |
a6bc4ca9 | 1053 | new_probe_locs = (uint64_t *) realloc(probe_locs, new_size); |
8bd52288 FD |
1054 | if (!new_probe_locs) { |
1055 | /* Error allocating a larger buffer */ | |
1056 | DBG("Allocation error in SDT."); | |
1057 | ret = LTTNG_ERR_NOMEM; | |
1058 | goto realloc_error; | |
1059 | } | |
1060 | probe_locs = new_probe_locs; | |
1061 | new_probe_locs = NULL; | |
1062 | ||
1063 | /* | |
1064 | * Use the virtual address of the probe to compute the offset of | |
1065 | * this probe from the beginning of the executable file. | |
1066 | */ | |
1067 | ret = lttng_elf_convert_addr_in_text_to_offset(elf, | |
1068 | curr_probe_location, &curr_probe_offset); | |
1069 | if (ret) { | |
1070 | DBG("Conversion error in SDT."); | |
1071 | goto realloc_error; | |
1072 | } | |
1073 | ||
1074 | probe_locs[nb_match - 1] = curr_probe_offset; | |
1075 | } | |
1076 | } | |
1077 | ||
1078 | end: | |
1079 | free(stap_note_section_data); | |
1080 | destroy_elf_error: | |
1081 | lttng_elf_destroy(elf); | |
1082 | error: | |
1083 | return ret; | |
1084 | realloc_error: | |
1085 | free(probe_locs); | |
1086 | goto end; | |
1087 | } |