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 | ||
c9e313bc SM |
10 | #include <common/compat/endian.hpp> |
11 | #include <common/error.hpp> | |
12 | #include <common/lttng-elf.hpp> | |
13 | #include <common/macros.hpp> | |
14 | #include <common/readwrite.hpp> | |
28ab034a JG |
15 | |
16 | #include <algorithm> | |
17 | #include <elf.h> | |
d0927b41 FD |
18 | #include <fcntl.h> |
19 | #include <stdbool.h> | |
20 | #include <stdint.h> | |
21 | #include <stdlib.h> | |
22 | #include <string.h> | |
23 | #include <sys/stat.h> | |
24 | #include <sys/types.h> | |
25 | #include <unistd.h> | |
26 | ||
28ab034a JG |
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" | |
28ab034a JG |
33 | #define NOTE_STAPSDT_SECTION_NAME ".note.stapsdt" |
34 | #define NOTE_STAPSDT_NAME "stapsdt" | |
35 | #define NOTE_STAPSDT_TYPE 3 | |
5c7248cd | 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 | ||
5c7248cd | 44 | #define next_4bytes_boundary(x) (typeof(x)) ((((uint64_t) (x)) + 3) & ~0x03) |
28ab034a | 45 | |
5c7248cd JG |
46 | #define bswap(x) \ |
47 | do { \ | |
48 | switch (sizeof(x)) { \ | |
49 | case 8: \ | |
50 | (x) = be64toh((uint64_t) (x)); \ | |
51 | break; \ | |
52 | case 4: \ | |
53 | (x) = be32toh((uint32_t) (x)); \ | |
54 | break; \ | |
55 | case 2: \ | |
56 | (x) = be16toh((uint16_t) (x)); \ | |
57 | break; \ | |
58 | case 1: \ | |
59 | break; \ | |
60 | default: \ | |
61 | abort(); \ | |
62 | } \ | |
d0927b41 FD |
63 | } while (0) |
64 | ||
28ab034a JG |
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); \ | |
d0927b41 | 71 | bswap((shdr).sh_offset); \ |
28ab034a JG |
72 | bswap((shdr).sh_size); \ |
73 | bswap((shdr).sh_link); \ | |
74 | bswap((shdr).sh_info); \ | |
d0927b41 FD |
75 | bswap((shdr).sh_addralign); \ |
76 | bswap((shdr).sh_entsize); \ | |
77 | } while (0) | |
78 | ||
28ab034a JG |
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); \ | |
d0927b41 FD |
94 | } while (0) |
95 | ||
28ab034a JG |
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; \ | |
d0927b41 FD |
108 | } while (0) |
109 | ||
28ab034a JG |
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; \ | |
d0927b41 FD |
125 | } while (0) |
126 | ||
5c7248cd JG |
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; \ | |
d0927b41 FD |
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 | 148 | |
f1494934 | 149 | namespace { |
d0927b41 FD |
150 | struct lttng_elf_ehdr { |
151 | uint16_t e_type; | |
152 | uint16_t e_machine; | |
153 | uint32_t e_version; | |
154 | uint64_t e_entry; | |
155 | uint64_t e_phoff; | |
156 | uint64_t e_shoff; | |
157 | uint32_t e_flags; | |
158 | uint16_t e_ehsize; | |
159 | uint16_t e_phentsize; | |
160 | uint16_t e_phnum; | |
161 | uint16_t e_shentsize; | |
162 | uint16_t e_shnum; | |
163 | uint16_t e_shstrndx; | |
164 | }; | |
165 | ||
166 | struct lttng_elf_shdr { | |
167 | uint32_t sh_name; | |
168 | uint32_t sh_type; | |
169 | uint64_t sh_flags; | |
170 | uint64_t sh_addr; | |
171 | uint64_t sh_offset; | |
172 | uint64_t sh_size; | |
173 | uint32_t sh_link; | |
174 | uint32_t sh_info; | |
175 | uint64_t sh_addralign; | |
176 | uint64_t sh_entsize; | |
177 | }; | |
178 | ||
179 | /* | |
180 | * This struct can hold both 32bit and 64bit symbol description. It's used with | |
181 | * the copy_sym() macro. Using this abstraction, we can use the same code for | |
182 | * both bitness. | |
183 | */ | |
184 | struct lttng_elf_sym { | |
185 | uint32_t st_name; | |
28ab034a JG |
186 | uint8_t st_info; |
187 | uint8_t st_other; | |
d0927b41 FD |
188 | uint16_t st_shndx; |
189 | uint64_t st_value; | |
190 | uint64_t st_size; | |
191 | }; | |
f1494934 | 192 | } /* namespace */ |
d0927b41 FD |
193 | |
194 | struct lttng_elf { | |
195 | int fd; | |
b7e59a88 | 196 | size_t file_size; |
d0927b41 FD |
197 | uint8_t bitness; |
198 | uint8_t endianness; | |
199 | /* Offset in bytes to start of section names string table. */ | |
200 | off_t section_names_offset; | |
201 | /* Size in bytes of section names string table. */ | |
202 | size_t section_names_size; | |
203 | struct lttng_elf_ehdr *ehdr; | |
204 | }; | |
205 | ||
28ab034a | 206 | static inline int is_elf_32_bit(struct lttng_elf *elf) |
d0927b41 FD |
207 | { |
208 | return elf->bitness == ELFCLASS32; | |
209 | } | |
210 | ||
28ab034a | 211 | static inline int is_elf_native_endian(struct lttng_elf *elf) |
d0927b41 FD |
212 | { |
213 | return elf->endianness == NATIVE_ELF_ENDIANNESS; | |
214 | } | |
215 | ||
28ab034a JG |
216 | static int |
217 | populate_section_header(struct lttng_elf *elf, struct lttng_elf_shdr *shdr, uint32_t index) | |
d0927b41 FD |
218 | { |
219 | int ret = 0; | |
220 | off_t offset; | |
221 | ||
222 | /* Compute the offset of the section in the file */ | |
28ab034a | 223 | offset = (off_t) elf->ehdr->e_shoff + (off_t) index * elf->ehdr->e_shentsize; |
d0927b41 FD |
224 | |
225 | if (lseek(elf->fd, offset, SEEK_SET) < 0) { | |
226 | PERROR("Error seeking to the beginning of ELF section header"); | |
227 | ret = -1; | |
228 | goto error; | |
229 | } | |
230 | ||
231 | if (is_elf_32_bit(elf)) { | |
232 | Elf32_Shdr elf_shdr; | |
233 | ||
234 | if (lttng_read(elf->fd, &elf_shdr, sizeof(elf_shdr)) < sizeof(elf_shdr)) { | |
235 | PERROR("Error reading ELF section header"); | |
236 | ret = -1; | |
237 | goto error; | |
238 | } | |
239 | if (!is_elf_native_endian(elf)) { | |
240 | bswap_shdr(elf_shdr); | |
241 | } | |
242 | copy_shdr(elf_shdr, *shdr); | |
243 | } else { | |
244 | Elf64_Shdr elf_shdr; | |
245 | ||
246 | if (lttng_read(elf->fd, &elf_shdr, sizeof(elf_shdr)) < sizeof(elf_shdr)) { | |
247 | PERROR("Error reading ELF section header"); | |
248 | ret = -1; | |
249 | goto error; | |
250 | } | |
251 | if (!is_elf_native_endian(elf)) { | |
252 | bswap_shdr(elf_shdr); | |
253 | } | |
254 | copy_shdr(elf_shdr, *shdr); | |
255 | } | |
256 | ||
257 | error: | |
258 | return ret; | |
259 | } | |
260 | ||
28ab034a | 261 | static int populate_elf_header(struct lttng_elf *elf) |
d0927b41 FD |
262 | { |
263 | int ret = 0; | |
264 | ||
265 | /* | |
266 | * Move the read pointer back to the beginning to read the full header | |
267 | * and copy it in our structure. | |
268 | */ | |
269 | if (lseek(elf->fd, 0, SEEK_SET) < 0) { | |
270 | PERROR("Error seeking to the beginning of the file"); | |
271 | ret = -1; | |
272 | goto error; | |
273 | } | |
274 | ||
275 | /* | |
276 | * Use macros to set fields in the ELF header struct for both 32bit and | |
277 | * 64bit. | |
278 | */ | |
279 | if (is_elf_32_bit(elf)) { | |
280 | Elf32_Ehdr elf_ehdr; | |
281 | ||
282 | if (lttng_read(elf->fd, &elf_ehdr, sizeof(elf_ehdr)) < sizeof(elf_ehdr)) { | |
283 | ret = -1; | |
284 | goto error; | |
285 | } | |
286 | if (!is_elf_native_endian(elf)) { | |
287 | bswap_ehdr(elf_ehdr); | |
288 | } | |
289 | copy_ehdr(elf_ehdr, *(elf->ehdr)); | |
290 | } else { | |
291 | Elf64_Ehdr elf_ehdr; | |
292 | ||
293 | if (lttng_read(elf->fd, &elf_ehdr, sizeof(elf_ehdr)) < sizeof(elf_ehdr)) { | |
294 | ret = -1; | |
295 | goto error; | |
296 | } | |
297 | if (!is_elf_native_endian(elf)) { | |
298 | bswap_ehdr(elf_ehdr); | |
299 | } | |
300 | copy_ehdr(elf_ehdr, *(elf->ehdr)); | |
301 | } | |
302 | error: | |
303 | return ret; | |
304 | } | |
305 | ||
306 | /* | |
307 | * Retrieve the nth (where n is the `index` argument) shdr (section | |
308 | * header) from the given elf instance. | |
309 | * | |
22fae25a | 310 | * 0 is returned on succes, -1 on failure. |
d0927b41 | 311 | */ |
28ab034a JG |
312 | static int |
313 | lttng_elf_get_section_hdr(struct lttng_elf *elf, uint16_t index, struct lttng_elf_shdr *out_header) | |
d0927b41 | 314 | { |
d0927b41 FD |
315 | int ret = 0; |
316 | ||
317 | if (!elf) { | |
22fae25a | 318 | ret = -1; |
d0927b41 FD |
319 | goto error; |
320 | } | |
321 | ||
322 | if (index >= elf->ehdr->e_shnum) { | |
22fae25a | 323 | ret = -1; |
d0927b41 FD |
324 | goto error; |
325 | } | |
326 | ||
22fae25a | 327 | ret = populate_section_header(elf, out_header, index); |
d0927b41 | 328 | if (ret) { |
d0927b41 FD |
329 | DBG("Error populating section header."); |
330 | goto error; | |
331 | } | |
d0927b41 FD |
332 | |
333 | error: | |
22fae25a | 334 | return ret; |
d0927b41 FD |
335 | } |
336 | ||
337 | /* | |
338 | * Lookup a section's name from a given offset (usually from an shdr's | |
339 | * sh_name value) in bytes relative to the beginning of the section | |
340 | * names string table. | |
341 | * | |
342 | * If no name is found, NULL is returned. | |
343 | */ | |
28ab034a | 344 | static char *lttng_elf_get_section_name(struct lttng_elf *elf, off_t offset) |
d0927b41 | 345 | { |
cd9adb8b | 346 | char *name = nullptr; |
28ab034a | 347 | size_t name_length = 0, to_read; /* name_length does not include \0 */ |
d0927b41 FD |
348 | |
349 | if (!elf) { | |
350 | goto error; | |
351 | } | |
352 | ||
353 | if (offset >= elf->section_names_size) { | |
354 | goto error; | |
355 | } | |
356 | ||
357 | if (lseek(elf->fd, elf->section_names_offset + offset, SEEK_SET) < 0) { | |
358 | PERROR("Error seeking to the beginning of ELF string table section"); | |
359 | goto error; | |
360 | } | |
361 | ||
362 | to_read = elf->section_names_size - offset; | |
363 | ||
364 | /* Find first \0 after or at current location, remember name_length. */ | |
365 | for (;;) { | |
366 | char buf[BUF_LEN]; | |
367 | ssize_t read_len; | |
368 | size_t i; | |
369 | ||
370 | if (!to_read) { | |
371 | goto error; | |
372 | } | |
a6bc4ca9 | 373 | read_len = lttng_read(elf->fd, buf, std::min<size_t>(BUF_LEN, to_read)); |
d0927b41 FD |
374 | if (read_len <= 0) { |
375 | PERROR("Error reading ELF string table section"); | |
376 | goto error; | |
377 | } | |
378 | for (i = 0; i < read_len; i++) { | |
379 | if (buf[i] == '\0') { | |
380 | name_length += i; | |
381 | goto end; | |
382 | } | |
383 | } | |
384 | name_length += read_len; | |
385 | to_read -= read_len; | |
386 | } | |
387 | end: | |
388 | /* | |
389 | * We found the length of the section name, now seek back to the | |
390 | * beginning of the name and copy it in the newly allocated buffer. | |
391 | */ | |
28ab034a | 392 | name = calloc<char>((name_length + 1)); /* + 1 for \0 */ |
d0927b41 FD |
393 | if (!name) { |
394 | PERROR("Error allocating ELF section name buffer"); | |
395 | goto error; | |
396 | } | |
397 | if (lseek(elf->fd, elf->section_names_offset + offset, SEEK_SET) < 0) { | |
398 | PERROR("Error seeking to the offset of the ELF section name"); | |
399 | goto error; | |
400 | } | |
401 | if (lttng_read(elf->fd, name, name_length + 1) < name_length + 1) { | |
402 | PERROR("Error reading the ELF section name"); | |
403 | goto error; | |
404 | } | |
405 | ||
406 | return name; | |
407 | ||
408 | error: | |
409 | free(name); | |
cd9adb8b | 410 | return nullptr; |
d0927b41 FD |
411 | } |
412 | ||
28ab034a | 413 | static int lttng_elf_validate_and_populate(struct lttng_elf *elf) |
d0927b41 FD |
414 | { |
415 | uint8_t version; | |
416 | uint8_t e_ident[EI_NIDENT]; | |
cd9adb8b | 417 | uint8_t *magic_number = nullptr; |
d0927b41 FD |
418 | int ret = 0; |
419 | ||
420 | if (elf->fd == -1) { | |
421 | DBG("fd error"); | |
422 | ret = LTTNG_ERR_ELF_PARSING; | |
423 | goto end; | |
424 | } | |
425 | ||
426 | /* | |
427 | * First read the magic number, endianness and version to later populate | |
428 | * the ELF header with the correct endianness and bitness. | |
429 | * (see elf.h) | |
430 | */ | |
431 | ||
432 | if (lseek(elf->fd, 0, SEEK_SET) < 0) { | |
433 | PERROR("Error seeking the beginning of ELF file"); | |
434 | ret = LTTNG_ERR_ELF_PARSING; | |
435 | goto end; | |
436 | } | |
437 | ret = lttng_read(elf->fd, e_ident, EI_NIDENT); | |
438 | if (ret < EI_NIDENT) { | |
439 | DBG("Error reading the ELF identification fields"); | |
440 | if (ret == -1) { | |
441 | PERROR("Error reading the ELF identification fields"); | |
442 | } | |
443 | ret = LTTNG_ERR_ELF_PARSING; | |
444 | goto end; | |
445 | } | |
446 | ||
447 | /* | |
448 | * Copy fields used to check that the target file is in fact a valid ELF | |
449 | * file. | |
450 | */ | |
451 | elf->bitness = e_ident[EI_CLASS]; | |
452 | elf->endianness = e_ident[EI_DATA]; | |
453 | version = e_ident[EI_VERSION]; | |
454 | magic_number = &e_ident[EI_MAG0]; | |
455 | ||
456 | /* | |
457 | * Check the magic number. | |
458 | */ | |
459 | if (memcmp(magic_number, ELFMAG, SELFMAG) != 0) { | |
460 | DBG("Error check ELF magic number."); | |
461 | ret = LTTNG_ERR_ELF_PARSING; | |
462 | goto end; | |
463 | } | |
464 | ||
465 | /* | |
466 | * Check the bitness is either ELFCLASS32 or ELFCLASS64. | |
467 | */ | |
468 | if (elf->bitness <= ELFCLASSNONE || elf->bitness >= ELFCLASSNUM) { | |
469 | DBG("ELF class error."); | |
470 | ret = LTTNG_ERR_ELF_PARSING; | |
471 | goto end; | |
472 | } | |
473 | ||
474 | /* | |
475 | * Check the endianness is either ELFDATA2LSB or ELFDATA2MSB. | |
476 | */ | |
477 | if (elf->endianness <= ELFDATANONE || elf->endianness >= ELFDATANUM) { | |
478 | DBG("ELF endianness error."); | |
479 | ret = LTTNG_ERR_ELF_PARSING; | |
480 | goto end; | |
481 | } | |
482 | ||
483 | /* | |
484 | * Check the version is ELF_CURRENT. | |
485 | */ | |
486 | if (version <= EV_NONE || version >= EV_NUM) { | |
487 | DBG("Wrong ELF version."); | |
488 | ret = LTTNG_ERR_ELF_PARSING; | |
489 | goto end; | |
490 | } | |
491 | ||
64803277 | 492 | elf->ehdr = zmalloc<lttng_elf_ehdr>(); |
d0927b41 FD |
493 | if (!elf->ehdr) { |
494 | PERROR("Error allocation buffer for ELF header"); | |
495 | ret = LTTNG_ERR_NOMEM; | |
496 | goto end; | |
497 | } | |
498 | ||
499 | /* | |
500 | * Copy the content of the elf header. | |
501 | */ | |
502 | ret = populate_elf_header(elf); | |
503 | if (ret) { | |
504 | DBG("Error reading ELF header,"); | |
505 | goto free_elf_error; | |
506 | } | |
507 | ||
508 | goto end; | |
509 | ||
510 | free_elf_error: | |
511 | free(elf->ehdr); | |
cd9adb8b | 512 | elf->ehdr = nullptr; |
d0927b41 FD |
513 | end: |
514 | return ret; | |
515 | } | |
516 | ||
517 | /* | |
518 | * Create an instance of lttng_elf for the ELF file located at | |
519 | * `path`. | |
520 | * | |
521 | * Return a pointer to the instance on success, NULL on failure. | |
522 | */ | |
28ab034a | 523 | static struct lttng_elf *lttng_elf_create(int fd) |
d0927b41 | 524 | { |
22fae25a | 525 | struct lttng_elf_shdr section_names_shdr; |
cd9adb8b | 526 | struct lttng_elf *elf = nullptr; |
d0927b41 | 527 | int ret; |
b7e59a88 | 528 | struct stat stat_buf; |
d0927b41 FD |
529 | |
530 | if (fd < 0) { | |
531 | goto error; | |
532 | } | |
533 | ||
b7e59a88 JG |
534 | ret = fstat(fd, &stat_buf); |
535 | if (ret) { | |
536 | PERROR("Failed to determine size of elf file"); | |
537 | goto error; | |
538 | } | |
539 | if (!S_ISREG(stat_buf.st_mode)) { | |
540 | ERR("Refusing to initialize lttng_elf from non-regular file"); | |
541 | goto error; | |
542 | } | |
543 | ||
64803277 | 544 | elf = zmalloc<lttng_elf>(); |
d0927b41 FD |
545 | if (!elf) { |
546 | PERROR("Error allocating struct lttng_elf"); | |
547 | goto error; | |
548 | } | |
b7e59a88 | 549 | elf->file_size = (size_t) stat_buf.st_size; |
d0927b41 FD |
550 | |
551 | elf->fd = dup(fd); | |
552 | if (elf->fd < 0) { | |
553 | PERROR("Error duplicating file descriptor to binary"); | |
554 | goto error; | |
555 | } | |
556 | ||
557 | ret = lttng_elf_validate_and_populate(elf); | |
558 | if (ret) { | |
559 | goto error; | |
560 | } | |
561 | ||
28ab034a | 562 | ret = lttng_elf_get_section_hdr(elf, elf->ehdr->e_shstrndx, §ion_names_shdr); |
22fae25a | 563 | if (ret) { |
d0927b41 FD |
564 | goto error; |
565 | } | |
566 | ||
22fae25a JG |
567 | elf->section_names_offset = section_names_shdr.sh_offset; |
568 | elf->section_names_size = section_names_shdr.sh_size; | |
d0927b41 FD |
569 | return elf; |
570 | ||
571 | error: | |
572 | if (elf) { | |
573 | if (elf->ehdr) { | |
574 | free(elf->ehdr); | |
575 | } | |
576 | if (elf->fd >= 0) { | |
577 | if (close(elf->fd)) { | |
578 | PERROR("Error closing file descriptor in error path"); | |
579 | abort(); | |
580 | } | |
581 | } | |
582 | free(elf); | |
583 | } | |
cd9adb8b | 584 | return nullptr; |
d0927b41 FD |
585 | } |
586 | ||
587 | /* | |
588 | * Destroy the given lttng_elf instance. | |
589 | */ | |
28ab034a | 590 | static void lttng_elf_destroy(struct lttng_elf *elf) |
d0927b41 FD |
591 | { |
592 | if (!elf) { | |
593 | return; | |
594 | } | |
595 | ||
596 | free(elf->ehdr); | |
597 | if (close(elf->fd)) { | |
598 | PERROR("Error closing file description in error path"); | |
599 | abort(); | |
600 | } | |
601 | free(elf); | |
602 | } | |
603 | ||
28ab034a JG |
604 | static int lttng_elf_get_section_hdr_by_name(struct lttng_elf *elf, |
605 | const char *section_name, | |
606 | struct lttng_elf_shdr *section_hdr) | |
d0927b41 FD |
607 | { |
608 | int i; | |
609 | char *curr_section_name; | |
22fae25a | 610 | |
d0927b41 | 611 | for (i = 0; i < elf->ehdr->e_shnum; ++i) { |
4e0b99ca | 612 | bool name_equal; |
28ab034a | 613 | int ret = lttng_elf_get_section_hdr(elf, i, section_hdr); |
d0927b41 | 614 | |
22fae25a JG |
615 | if (ret) { |
616 | break; | |
617 | } | |
28ab034a | 618 | curr_section_name = lttng_elf_get_section_name(elf, section_hdr->sh_name); |
d0927b41 FD |
619 | if (!curr_section_name) { |
620 | continue; | |
621 | } | |
4e0b99ca JG |
622 | name_equal = strcmp(curr_section_name, section_name) == 0; |
623 | free(curr_section_name); | |
624 | if (name_equal) { | |
d0927b41 FD |
625 | return 0; |
626 | } | |
627 | } | |
628 | return LTTNG_ERR_ELF_PARSING; | |
629 | } | |
630 | ||
28ab034a | 631 | static char *lttng_elf_get_section_data(struct lttng_elf *elf, struct lttng_elf_shdr *shdr) |
d0927b41 FD |
632 | { |
633 | int ret; | |
634 | off_t section_offset; | |
635 | char *data; | |
ee5b998f | 636 | size_t max_alloc_size; |
d0927b41 FD |
637 | |
638 | if (!elf || !shdr) { | |
639 | goto error; | |
640 | } | |
641 | ||
a6bc4ca9 | 642 | max_alloc_size = std::min<size_t>(MAX_SECTION_DATA_SIZE, elf->file_size); |
ee5b998f | 643 | |
d0927b41 FD |
644 | section_offset = shdr->sh_offset; |
645 | if (lseek(elf->fd, section_offset, SEEK_SET) < 0) { | |
646 | PERROR("Error seeking to section offset"); | |
647 | goto error; | |
648 | } | |
649 | ||
b7e59a88 | 650 | if (shdr->sh_size > max_alloc_size) { |
28ab034a | 651 | ERR("ELF section size exceeds maximal allowed size of %zu bytes", max_alloc_size); |
b7e59a88 JG |
652 | goto error; |
653 | } | |
64803277 | 654 | data = calloc<char>(shdr->sh_size); |
d0927b41 FD |
655 | if (!data) { |
656 | PERROR("Error allocating buffer for ELF section data"); | |
657 | goto error; | |
658 | } | |
659 | ret = lttng_read(elf->fd, data, shdr->sh_size); | |
660 | if (ret == -1) { | |
661 | PERROR("Error reading ELF section data"); | |
662 | goto free_error; | |
663 | } | |
664 | ||
665 | return data; | |
666 | ||
667 | free_error: | |
668 | free(data); | |
669 | error: | |
cd9adb8b | 670 | return nullptr; |
d0927b41 FD |
671 | } |
672 | ||
673 | /* | |
674 | * Convert the virtual address in a binary's mapping to the offset of | |
675 | * the corresponding instruction in the binary file. | |
676 | * This function assumes the address is in the text section. | |
677 | * | |
678 | * Returns the offset on success or non-zero in case of failure. | |
679 | */ | |
28ab034a JG |
680 | static int lttng_elf_convert_addr_in_text_to_offset(struct lttng_elf *elf_handle, |
681 | size_t addr, | |
682 | uint64_t *offset) | |
d0927b41 FD |
683 | { |
684 | int ret = 0; | |
685 | off_t text_section_offset; | |
686 | off_t text_section_addr_beg; | |
687 | off_t text_section_addr_end; | |
688 | off_t offset_in_section; | |
22fae25a | 689 | struct lttng_elf_shdr text_section_hdr; |
d0927b41 FD |
690 | |
691 | if (!elf_handle) { | |
692 | DBG("Invalid ELF handle."); | |
693 | ret = LTTNG_ERR_ELF_PARSING; | |
694 | goto error; | |
695 | } | |
696 | ||
697 | /* Get a pointer to the .text section header. */ | |
28ab034a | 698 | ret = lttng_elf_get_section_hdr_by_name(elf_handle, TEXT_SECTION_NAME, &text_section_hdr); |
d0927b41 FD |
699 | if (ret) { |
700 | DBG("Text section not found in binary."); | |
701 | ret = LTTNG_ERR_ELF_PARSING; | |
702 | goto error; | |
703 | } | |
704 | ||
22fae25a JG |
705 | text_section_offset = text_section_hdr.sh_offset; |
706 | text_section_addr_beg = text_section_hdr.sh_addr; | |
28ab034a | 707 | text_section_addr_end = text_section_addr_beg + text_section_hdr.sh_size; |
d0927b41 FD |
708 | |
709 | /* | |
710 | * Verify that the address is within the .text section boundaries. | |
711 | */ | |
712 | if (addr < text_section_addr_beg || addr > text_section_addr_end) { | |
713 | DBG("Address found is outside of the .text section addr=0x%zx, " | |
28ab034a JG |
714 | ".text section=[0x%jd - 0x%jd].", |
715 | addr, | |
716 | (intmax_t) text_section_addr_beg, | |
717 | (intmax_t) text_section_addr_end); | |
d0927b41 FD |
718 | ret = LTTNG_ERR_ELF_PARSING; |
719 | goto error; | |
720 | } | |
721 | ||
722 | offset_in_section = addr - text_section_addr_beg; | |
723 | ||
724 | /* | |
725 | * Add the target offset in the text section to the offset of this text | |
726 | * section from the beginning of the binary file. | |
727 | */ | |
728 | *offset = text_section_offset + offset_in_section; | |
729 | ||
730 | error: | |
731 | return ret; | |
732 | } | |
733 | ||
734 | /* | |
735 | * Compute the offset of a symbol from the begining of the ELF binary. | |
736 | * | |
737 | * On success, returns 0 offset parameter is set to the computed value | |
738 | * On failure, returns -1. | |
739 | */ | |
740 | int lttng_elf_get_symbol_offset(int fd, char *symbol, uint64_t *offset) | |
741 | { | |
742 | int ret = 0; | |
743 | int sym_found = 0; | |
744 | int sym_count = 0; | |
745 | int sym_idx = 0; | |
746 | uint64_t addr = 0; | |
cd9adb8b JG |
747 | char *curr_sym_str = nullptr; |
748 | char *symbol_table_data = nullptr; | |
749 | char *string_table_data = nullptr; | |
750 | const char *string_table_name = nullptr; | |
22fae25a JG |
751 | struct lttng_elf_shdr symtab_hdr; |
752 | struct lttng_elf_shdr strtab_hdr; | |
cd9adb8b | 753 | struct lttng_elf *elf = nullptr; |
d0927b41 | 754 | |
28ab034a | 755 | if (!symbol || !offset) { |
d0927b41 FD |
756 | ret = LTTNG_ERR_ELF_PARSING; |
757 | goto end; | |
758 | } | |
759 | ||
760 | elf = lttng_elf_create(fd); | |
761 | if (!elf) { | |
762 | ret = LTTNG_ERR_ELF_PARSING; | |
763 | goto end; | |
764 | } | |
765 | ||
ef3dfe5d FD |
766 | /* |
767 | * The .symtab section might not exist on stripped binaries. | |
768 | * Try to get the symbol table section header first. If it's absent, | |
769 | * try to get the dynamic symbol table. All symbols in the dynamic | |
770 | * symbol tab are in the (normal) symbol table if it exists. | |
771 | */ | |
28ab034a | 772 | ret = lttng_elf_get_section_hdr_by_name(elf, SYMBOL_TAB_SECTION_NAME, &symtab_hdr); |
d0927b41 | 773 | if (ret) { |
ef3dfe5d FD |
774 | DBG("Cannot get ELF Symbol Table section. Trying to get ELF Dynamic Symbol Table section."); |
775 | /* Get the dynamic symbol table section header. */ | |
28ab034a JG |
776 | ret = lttng_elf_get_section_hdr_by_name( |
777 | elf, DYNAMIC_SYMBOL_TAB_SECTION_NAME, &symtab_hdr); | |
ef3dfe5d FD |
778 | if (ret) { |
779 | DBG("Cannot get ELF Symbol Table nor Dynamic Symbol Table sections."); | |
780 | ret = LTTNG_ERR_ELF_PARSING; | |
781 | goto destroy_elf; | |
782 | } | |
783 | string_table_name = DYNAMIC_STRING_TAB_SECTION_NAME; | |
784 | } else { | |
785 | string_table_name = STRING_TAB_SECTION_NAME; | |
d0927b41 | 786 | } |
ef3dfe5d | 787 | |
d0927b41 | 788 | /* Get the data associated with the symbol table section. */ |
22fae25a | 789 | symbol_table_data = lttng_elf_get_section_data(elf, &symtab_hdr); |
cd9adb8b | 790 | if (symbol_table_data == nullptr) { |
d0927b41 FD |
791 | DBG("Cannot get ELF Symbol Table data."); |
792 | ret = LTTNG_ERR_ELF_PARSING; | |
793 | goto destroy_elf; | |
794 | } | |
795 | ||
796 | /* Get the string table section header. */ | |
28ab034a | 797 | ret = lttng_elf_get_section_hdr_by_name(elf, string_table_name, &strtab_hdr); |
d0927b41 FD |
798 | if (ret) { |
799 | DBG("Cannot get ELF string table section."); | |
800 | goto free_symbol_table_data; | |
801 | } | |
802 | ||
803 | /* Get the data associated with the string table section. */ | |
22fae25a | 804 | string_table_data = lttng_elf_get_section_data(elf, &strtab_hdr); |
cd9adb8b | 805 | if (string_table_data == nullptr) { |
d0927b41 FD |
806 | DBG("Cannot get ELF string table section data."); |
807 | ret = LTTNG_ERR_ELF_PARSING; | |
808 | goto free_symbol_table_data; | |
809 | } | |
810 | ||
811 | /* Get the number of symbol in the table for the iteration. */ | |
a395e079 JG |
812 | if (symtab_hdr.sh_entsize == 0) { |
813 | DBG("Invalid ELF string table entry size."); | |
814 | ret = LTTNG_ERR_ELF_PARSING; | |
3308655a | 815 | goto free_string_table_data; |
a395e079 JG |
816 | } |
817 | ||
22fae25a | 818 | sym_count = symtab_hdr.sh_size / symtab_hdr.sh_entsize; |
d0927b41 FD |
819 | |
820 | /* Loop over all symbol. */ | |
821 | for (sym_idx = 0; sym_idx < sym_count; sym_idx++) { | |
822 | struct lttng_elf_sym curr_sym; | |
823 | ||
824 | /* Get the symbol at the current index. */ | |
825 | if (is_elf_32_bit(elf)) { | |
826 | Elf32_Sym tmp = ((Elf32_Sym *) symbol_table_data)[sym_idx]; | |
827 | copy_sym(tmp, curr_sym); | |
828 | } else { | |
829 | Elf64_Sym tmp = ((Elf64_Sym *) symbol_table_data)[sym_idx]; | |
830 | copy_sym(tmp, curr_sym); | |
831 | } | |
832 | ||
833 | /* | |
834 | * If the st_name field is zero, there is no string name for | |
835 | * this symbol; skip to the next symbol. | |
836 | */ | |
837 | if (curr_sym.st_name == 0) { | |
838 | continue; | |
839 | } | |
840 | ||
841 | /* | |
842 | * Use the st_name field in the lttng_elf_sym struct to get offset of | |
843 | * the symbol's name from the beginning of the string table. | |
844 | */ | |
845 | curr_sym_str = string_table_data + curr_sym.st_name; | |
846 | ||
847 | /* | |
848 | * If the current symbol is not a function; skip to the next symbol. | |
849 | */ | |
983a481e MJ |
850 | /* Both 32bit and 64bit use the same 1 byte field for type. (See elf.h) */ |
851 | if (ELF32_ST_TYPE(curr_sym.st_info) != STT_FUNC) { | |
d0927b41 FD |
852 | continue; |
853 | } | |
854 | ||
855 | /* | |
856 | * Compare with the search symbol. If there is a match set the address | |
857 | * output parameter and return success. | |
858 | */ | |
28ab034a | 859 | if (strcmp(symbol, curr_sym_str) == 0) { |
d0927b41 FD |
860 | sym_found = 1; |
861 | addr = curr_sym.st_value; | |
862 | break; | |
863 | } | |
864 | } | |
865 | ||
866 | if (!sym_found) { | |
867 | DBG("Symbol not found."); | |
868 | ret = LTTNG_ERR_ELF_PARSING; | |
869 | goto free_string_table_data; | |
870 | } | |
871 | ||
872 | /* | |
873 | * Use the virtual address of the symbol to compute the offset of this | |
874 | * symbol from the beginning of the executable file. | |
875 | */ | |
876 | ret = lttng_elf_convert_addr_in_text_to_offset(elf, addr, offset); | |
877 | if (ret) { | |
512df046 | 878 | DBG("Cannot convert addr to offset."); |
d0927b41 FD |
879 | goto free_string_table_data; |
880 | } | |
881 | ||
d0927b41 FD |
882 | free_string_table_data: |
883 | free(string_table_data); | |
884 | free_symbol_table_data: | |
885 | free(symbol_table_data); | |
886 | destroy_elf: | |
887 | lttng_elf_destroy(elf); | |
888 | end: | |
889 | return ret; | |
890 | } | |
8bd52288 FD |
891 | |
892 | /* | |
893 | * Compute the offsets of SDT probes from the begining of the ELF binary. | |
894 | * | |
895 | * On success, returns 0 and the nb_probes parameter is set to the number of | |
896 | * offsets found and the offsets parameter points to an array of offsets where | |
897 | * the SDT probes are. | |
898 | * On failure, returns -1. | |
899 | */ | |
28ab034a JG |
900 | int lttng_elf_get_sdt_probe_offsets(int fd, |
901 | const char *provider_name, | |
902 | const char *probe_name, | |
903 | uint64_t **offsets, | |
904 | uint32_t *nb_probes) | |
8bd52288 FD |
905 | { |
906 | int ret = 0, nb_match = 0; | |
22fae25a | 907 | struct lttng_elf_shdr stap_note_section_hdr; |
cd9adb8b JG |
908 | struct lttng_elf *elf = nullptr; |
909 | char *stap_note_section_data = nullptr; | |
8bd52288 | 910 | char *curr_note_section_begin, *curr_data_ptr, *curr_probe, *curr_provider; |
d3be5495 | 911 | char *next_note_ptr; |
8bd52288 FD |
912 | uint32_t name_size, desc_size, note_type; |
913 | uint64_t curr_probe_location, curr_probe_offset, curr_semaphore_location; | |
cd9adb8b | 914 | uint64_t *probe_locs = nullptr, *new_probe_locs = nullptr; |
8bd52288 FD |
915 | |
916 | if (!provider_name || !probe_name || !nb_probes || !offsets) { | |
917 | DBG("Invalid arguments."); | |
918 | ret = LTTNG_ERR_ELF_PARSING; | |
919 | goto error; | |
920 | } | |
921 | ||
922 | elf = lttng_elf_create(fd); | |
923 | if (!elf) { | |
924 | DBG("Error allocation ELF."); | |
925 | ret = LTTNG_ERR_ELF_PARSING; | |
926 | goto error; | |
927 | } | |
928 | ||
929 | /* Get the stap note section header. */ | |
28ab034a JG |
930 | ret = lttng_elf_get_section_hdr_by_name( |
931 | elf, NOTE_STAPSDT_SECTION_NAME, &stap_note_section_hdr); | |
8bd52288 FD |
932 | if (ret) { |
933 | DBG("Cannot get ELF stap note section."); | |
934 | goto destroy_elf_error; | |
935 | } | |
936 | ||
937 | /* Get the data associated with the stap note section. */ | |
28ab034a | 938 | stap_note_section_data = lttng_elf_get_section_data(elf, &stap_note_section_hdr); |
cd9adb8b | 939 | if (stap_note_section_data == nullptr) { |
8bd52288 FD |
940 | DBG("Cannot get ELF stap note section data."); |
941 | ret = LTTNG_ERR_ELF_PARSING; | |
942 | goto destroy_elf_error; | |
943 | } | |
944 | ||
8bd52288 FD |
945 | next_note_ptr = stap_note_section_data; |
946 | curr_note_section_begin = stap_note_section_data; | |
947 | ||
cd9adb8b JG |
948 | *offsets = nullptr; |
949 | while (true) { | |
8bd52288 FD |
950 | curr_data_ptr = next_note_ptr; |
951 | /* Check if we have reached the end of the note section. */ | |
28ab034a | 952 | if (curr_data_ptr >= curr_note_section_begin + stap_note_section_hdr.sh_size) { |
8bd52288 FD |
953 | *nb_probes = nb_match; |
954 | *offsets = probe_locs; | |
955 | ret = 0; | |
956 | break; | |
957 | } | |
958 | /* Get name size field. */ | |
28ab034a | 959 | name_size = next_4bytes_boundary(*(uint32_t *) curr_data_ptr); |
8bd52288 FD |
960 | curr_data_ptr += sizeof(uint32_t); |
961 | ||
962 | /* Sanity check; a zero name_size is reserved. */ | |
963 | if (name_size == 0) { | |
964 | DBG("Invalid name size field in SDT probe descriptions" | |
28ab034a | 965 | "section."); |
8bd52288 FD |
966 | ret = -1; |
967 | goto realloc_error; | |
968 | } | |
969 | ||
970 | /* Get description size field. */ | |
28ab034a | 971 | desc_size = next_4bytes_boundary(*(uint32_t *) curr_data_ptr); |
8bd52288 FD |
972 | curr_data_ptr += sizeof(uint32_t); |
973 | ||
974 | /* Get type field. */ | |
975 | note_type = *(uint32_t *) curr_data_ptr; | |
976 | curr_data_ptr += sizeof(uint32_t); | |
977 | ||
978 | /* | |
979 | * Move the pointer to the next note to be ready for the next | |
980 | * iteration. The current note is made of 3 unsigned 32bit | |
981 | * integers (name size, descriptor size and note type), the | |
982 | * name and the descriptor. To move to the next note, we move | |
983 | * the pointer according to those values. | |
984 | */ | |
28ab034a | 985 | next_note_ptr = next_note_ptr + (3 * sizeof(uint32_t)) + desc_size + name_size; |
8bd52288 FD |
986 | |
987 | /* | |
988 | * Move ptr to the end of the name string (we don't need it) | |
989 | * and go to the next 4 byte alignement. | |
990 | */ | |
991 | if (note_type != NOTE_STAPSDT_TYPE || | |
28ab034a | 992 | strncmp(curr_data_ptr, NOTE_STAPSDT_NAME, name_size) != 0) { |
8bd52288 FD |
993 | continue; |
994 | } | |
995 | ||
996 | curr_data_ptr += name_size; | |
997 | ||
8bd52288 FD |
998 | /* Get probe location. */ |
999 | curr_probe_location = *(uint64_t *) curr_data_ptr; | |
1000 | curr_data_ptr += sizeof(uint64_t); | |
1001 | ||
1002 | /* Pass over the base. Not needed. */ | |
1003 | curr_data_ptr += sizeof(uint64_t); | |
1004 | ||
1005 | /* Get semaphore location. */ | |
1006 | curr_semaphore_location = *(uint64_t *) curr_data_ptr; | |
1007 | curr_data_ptr += sizeof(uint64_t); | |
1008 | /* Get provider name. */ | |
1009 | curr_provider = curr_data_ptr; | |
1010 | curr_data_ptr += strlen(curr_provider) + 1; | |
1011 | ||
1012 | /* Get probe name. */ | |
1013 | curr_probe = curr_data_ptr; | |
8bd52288 FD |
1014 | |
1015 | /* Check if the provider and probe name match */ | |
1016 | if (strcmp(provider_name, curr_provider) == 0 && | |
28ab034a | 1017 | strcmp(probe_name, curr_probe) == 0) { |
8bd52288 FD |
1018 | int new_size; |
1019 | ||
1020 | /* | |
1021 | * We currently don't support SDT probes with semaphores. Return | |
1022 | * success as we found a matching probe but it's guarded by a | |
1023 | * semaphore. | |
1024 | */ | |
1025 | if (curr_semaphore_location != 0) { | |
1026 | ret = LTTNG_ERR_SDT_PROBE_SEMAPHORE; | |
09f3038c | 1027 | goto realloc_error; |
8bd52288 FD |
1028 | } |
1029 | ||
1030 | new_size = (++nb_match) * sizeof(uint64_t); | |
1031 | ||
1032 | /* | |
1033 | * Found a match with not semaphore, we need to copy the | |
1034 | * probe_location to the output parameter. | |
1035 | */ | |
a6bc4ca9 | 1036 | new_probe_locs = (uint64_t *) realloc(probe_locs, new_size); |
8bd52288 FD |
1037 | if (!new_probe_locs) { |
1038 | /* Error allocating a larger buffer */ | |
1039 | DBG("Allocation error in SDT."); | |
1040 | ret = LTTNG_ERR_NOMEM; | |
1041 | goto realloc_error; | |
1042 | } | |
1043 | probe_locs = new_probe_locs; | |
cd9adb8b | 1044 | new_probe_locs = nullptr; |
8bd52288 FD |
1045 | |
1046 | /* | |
1047 | * Use the virtual address of the probe to compute the offset of | |
1048 | * this probe from the beginning of the executable file. | |
1049 | */ | |
28ab034a JG |
1050 | ret = lttng_elf_convert_addr_in_text_to_offset( |
1051 | elf, curr_probe_location, &curr_probe_offset); | |
8bd52288 FD |
1052 | if (ret) { |
1053 | DBG("Conversion error in SDT."); | |
1054 | goto realloc_error; | |
1055 | } | |
1056 | ||
1057 | probe_locs[nb_match - 1] = curr_probe_offset; | |
1058 | } | |
1059 | } | |
1060 | ||
1061 | end: | |
1062 | free(stap_note_section_data); | |
1063 | destroy_elf_error: | |
1064 | lttng_elf_destroy(elf); | |
1065 | error: | |
1066 | return ret; | |
1067 | realloc_error: | |
1068 | free(probe_locs); | |
1069 | goto end; | |
1070 | } |