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442f04c3 JP |
1 | /* |
2 | * Copyright (C) 2015 Josh Poimboeuf <jpoimboe@redhat.com> | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or | |
5 | * modify it under the terms of the GNU General Public License | |
6 | * as published by the Free Software Foundation; either version 2 | |
7 | * of the License, or (at your option) any later version. | |
8 | * | |
9 | * This program 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 | |
12 | * GNU General Public License for more details. | |
13 | * | |
14 | * You should have received a copy of the GNU General Public License | |
15 | * along with this program; if not, see <http://www.gnu.org/licenses/>. | |
16 | */ | |
17 | ||
18 | /* | |
19 | * objtool check: | |
20 | * | |
21 | * This command analyzes every .o file and ensures the validity of its stack | |
22 | * trace metadata. It enforces a set of rules on asm code and C inline | |
23 | * assembly code so that stack traces can be reliable. | |
24 | * | |
25 | * For more information, see tools/objtool/Documentation/stack-validation.txt. | |
26 | */ | |
27 | ||
28 | #include <string.h> | |
d0761e37 | 29 | #include <stdlib.h> |
442f04c3 JP |
30 | #include <subcmd/parse-options.h> |
31 | ||
32 | #include "builtin.h" | |
33 | #include "elf.h" | |
34 | #include "special.h" | |
35 | #include "arch.h" | |
36 | #include "warn.h" | |
37 | ||
042ba73f JP |
38 | #include <linux/hashtable.h> |
39 | ||
442f04c3 JP |
40 | #define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0])) |
41 | ||
42 | #define STATE_FP_SAVED 0x1 | |
43 | #define STATE_FP_SETUP 0x2 | |
44 | #define STATE_FENTRY 0x4 | |
45 | ||
46 | struct instruction { | |
47 | struct list_head list; | |
042ba73f | 48 | struct hlist_node hash; |
442f04c3 JP |
49 | struct section *sec; |
50 | unsigned long offset; | |
51 | unsigned int len, state; | |
52 | unsigned char type; | |
53 | unsigned long immediate; | |
54 | bool alt_group, visited; | |
55 | struct symbol *call_dest; | |
56 | struct instruction *jump_dest; | |
57 | struct list_head alts; | |
b1547d31 | 58 | struct symbol *func; |
442f04c3 JP |
59 | }; |
60 | ||
61 | struct alternative { | |
62 | struct list_head list; | |
63 | struct instruction *insn; | |
64 | }; | |
65 | ||
66 | struct objtool_file { | |
67 | struct elf *elf; | |
a196e171 | 68 | struct list_head insn_list; |
042ba73f JP |
69 | DECLARE_HASHTABLE(insn_hash, 16); |
70 | struct section *rodata, *whitelist; | |
b1547d31 | 71 | bool ignore_unreachables, c_file; |
442f04c3 JP |
72 | }; |
73 | ||
74 | const char *objname; | |
75 | static bool nofp; | |
76 | ||
74aec058 JP |
77 | static struct instruction *find_insn(struct objtool_file *file, |
78 | struct section *sec, unsigned long offset) | |
442f04c3 JP |
79 | { |
80 | struct instruction *insn; | |
81 | ||
042ba73f | 82 | hash_for_each_possible(file->insn_hash, insn, hash, offset) |
442f04c3 JP |
83 | if (insn->sec == sec && insn->offset == offset) |
84 | return insn; | |
85 | ||
86 | return NULL; | |
87 | } | |
88 | ||
74aec058 JP |
89 | static struct instruction *next_insn_same_sec(struct objtool_file *file, |
90 | struct instruction *insn) | |
91 | { | |
92 | struct instruction *next = list_next_entry(insn, list); | |
93 | ||
a196e171 | 94 | if (&next->list == &file->insn_list || next->sec != insn->sec) |
74aec058 JP |
95 | return NULL; |
96 | ||
97 | return next; | |
98 | } | |
99 | ||
100 | #define for_each_insn(file, insn) \ | |
a196e171 | 101 | list_for_each_entry(insn, &file->insn_list, list) |
74aec058 JP |
102 | |
103 | #define func_for_each_insn(file, func, insn) \ | |
104 | for (insn = find_insn(file, func->sec, func->offset); \ | |
a196e171 | 105 | insn && &insn->list != &file->insn_list && \ |
74aec058 JP |
106 | insn->sec == func->sec && \ |
107 | insn->offset < func->offset + func->len; \ | |
108 | insn = list_next_entry(insn, list)) | |
109 | ||
110 | #define sec_for_each_insn_from(file, insn) \ | |
111 | for (; insn; insn = next_insn_same_sec(file, insn)) | |
112 | ||
113 | ||
442f04c3 JP |
114 | /* |
115 | * Check if the function has been manually whitelisted with the | |
116 | * STACK_FRAME_NON_STANDARD macro, or if it should be automatically whitelisted | |
117 | * due to its use of a context switching instruction. | |
118 | */ | |
119 | static bool ignore_func(struct objtool_file *file, struct symbol *func) | |
120 | { | |
442f04c3 JP |
121 | struct rela *rela; |
122 | struct instruction *insn; | |
123 | ||
124 | /* check for STACK_FRAME_NON_STANDARD */ | |
042ba73f | 125 | if (file->whitelist && file->whitelist->rela) |
0ea5ad86 JP |
126 | list_for_each_entry(rela, &file->whitelist->rela->rela_list, list) { |
127 | if (rela->sym->type == STT_SECTION && | |
128 | rela->sym->sec == func->sec && | |
442f04c3 JP |
129 | rela->addend == func->offset) |
130 | return true; | |
0ea5ad86 JP |
131 | if (rela->sym->type == STT_FUNC && rela->sym == func) |
132 | return true; | |
133 | } | |
442f04c3 JP |
134 | |
135 | /* check if it has a context switching instruction */ | |
74aec058 | 136 | func_for_each_insn(file, func, insn) |
442f04c3 JP |
137 | if (insn->type == INSN_CONTEXT_SWITCH) |
138 | return true; | |
442f04c3 JP |
139 | |
140 | return false; | |
141 | } | |
142 | ||
143 | /* | |
144 | * This checks to see if the given function is a "noreturn" function. | |
145 | * | |
146 | * For global functions which are outside the scope of this object file, we | |
147 | * have to keep a manual list of them. | |
148 | * | |
149 | * For local functions, we have to detect them manually by simply looking for | |
150 | * the lack of a return instruction. | |
b1e03249 JP |
151 | * |
152 | * Returns: | |
153 | * -1: error | |
154 | * 0: no dead end | |
155 | * 1: dead end | |
442f04c3 | 156 | */ |
b1e03249 JP |
157 | static int __dead_end_function(struct objtool_file *file, struct symbol *func, |
158 | int recursion) | |
442f04c3 JP |
159 | { |
160 | int i; | |
74aec058 | 161 | struct instruction *insn; |
442f04c3 JP |
162 | bool empty = true; |
163 | ||
164 | /* | |
165 | * Unfortunately these have to be hard coded because the noreturn | |
166 | * attribute isn't provided in ELF data. | |
167 | */ | |
168 | static const char * const global_noreturns[] = { | |
169 | "__stack_chk_fail", | |
170 | "panic", | |
171 | "do_exit", | |
172 | "__module_put_and_exit", | |
173 | "complete_and_exit", | |
174 | "kvm_spurious_fault", | |
175 | "__reiserfs_panic", | |
176 | "lbug_with_loc" | |
177 | }; | |
178 | ||
179 | if (func->bind == STB_WEAK) | |
b1e03249 | 180 | return 0; |
442f04c3 JP |
181 | |
182 | if (func->bind == STB_GLOBAL) | |
183 | for (i = 0; i < ARRAY_SIZE(global_noreturns); i++) | |
184 | if (!strcmp(func->name, global_noreturns[i])) | |
b1e03249 | 185 | return 1; |
442f04c3 JP |
186 | |
187 | if (!func->sec) | |
b1e03249 | 188 | return 0; |
442f04c3 | 189 | |
74aec058 | 190 | func_for_each_insn(file, func, insn) { |
442f04c3 JP |
191 | empty = false; |
192 | ||
193 | if (insn->type == INSN_RETURN) | |
b1e03249 | 194 | return 0; |
81bfafca JP |
195 | } |
196 | ||
197 | if (empty) | |
b1e03249 | 198 | return 0; |
81bfafca JP |
199 | |
200 | /* | |
201 | * A function can have a sibling call instead of a return. In that | |
202 | * case, the function's dead-end status depends on whether the target | |
203 | * of the sibling call returns. | |
204 | */ | |
74aec058 | 205 | func_for_each_insn(file, func, insn) { |
81bfafca JP |
206 | if (insn->sec != func->sec || |
207 | insn->offset >= func->offset + func->len) | |
208 | break; | |
442f04c3 JP |
209 | |
210 | if (insn->type == INSN_JUMP_UNCONDITIONAL) { | |
211 | struct instruction *dest = insn->jump_dest; | |
212 | struct symbol *dest_func; | |
213 | ||
214 | if (!dest) | |
215 | /* sibling call to another file */ | |
b1e03249 | 216 | return 0; |
442f04c3 JP |
217 | |
218 | if (dest->sec != func->sec || | |
219 | dest->offset < func->offset || | |
220 | dest->offset >= func->offset + func->len) { | |
221 | /* local sibling call */ | |
222 | dest_func = find_symbol_by_offset(dest->sec, | |
223 | dest->offset); | |
224 | if (!dest_func) | |
225 | continue; | |
226 | ||
b1e03249 JP |
227 | if (recursion == 5) { |
228 | WARN_FUNC("infinite recursion (objtool bug!)", | |
229 | dest->sec, dest->offset); | |
230 | return -1; | |
231 | } | |
232 | ||
233 | return __dead_end_function(file, dest_func, | |
234 | recursion + 1); | |
442f04c3 JP |
235 | } |
236 | } | |
237 | ||
b1547d31 | 238 | if (insn->type == INSN_JUMP_DYNAMIC && list_empty(&insn->alts)) |
442f04c3 | 239 | /* sibling call */ |
b1e03249 | 240 | return 0; |
442f04c3 JP |
241 | } |
242 | ||
b1e03249 JP |
243 | return 1; |
244 | } | |
245 | ||
246 | static int dead_end_function(struct objtool_file *file, struct symbol *func) | |
247 | { | |
248 | return __dead_end_function(file, func, 0); | |
442f04c3 JP |
249 | } |
250 | ||
251 | /* | |
252 | * Call the arch-specific instruction decoder for all the instructions and add | |
a196e171 | 253 | * them to the global instruction list. |
442f04c3 JP |
254 | */ |
255 | static int decode_instructions(struct objtool_file *file) | |
256 | { | |
257 | struct section *sec; | |
b1547d31 | 258 | struct symbol *func; |
442f04c3 JP |
259 | unsigned long offset; |
260 | struct instruction *insn; | |
261 | int ret; | |
262 | ||
442f04c3 JP |
263 | list_for_each_entry(sec, &file->elf->sections, list) { |
264 | ||
265 | if (!(sec->sh.sh_flags & SHF_EXECINSTR)) | |
266 | continue; | |
267 | ||
268 | for (offset = 0; offset < sec->len; offset += insn->len) { | |
269 | insn = malloc(sizeof(*insn)); | |
270 | memset(insn, 0, sizeof(*insn)); | |
271 | ||
272 | INIT_LIST_HEAD(&insn->alts); | |
273 | insn->sec = sec; | |
274 | insn->offset = offset; | |
275 | ||
276 | ret = arch_decode_instruction(file->elf, sec, offset, | |
277 | sec->len - offset, | |
278 | &insn->len, &insn->type, | |
279 | &insn->immediate); | |
280 | if (ret) | |
281 | return ret; | |
282 | ||
283 | if (!insn->type || insn->type > INSN_LAST) { | |
284 | WARN_FUNC("invalid instruction type %d", | |
285 | insn->sec, insn->offset, insn->type); | |
286 | return -1; | |
287 | } | |
288 | ||
042ba73f | 289 | hash_add(file->insn_hash, &insn->hash, insn->offset); |
a196e171 | 290 | list_add_tail(&insn->list, &file->insn_list); |
442f04c3 | 291 | } |
b1547d31 JP |
292 | |
293 | list_for_each_entry(func, &sec->symbol_list, list) { | |
294 | if (func->type != STT_FUNC) | |
295 | continue; | |
296 | ||
297 | if (!find_insn(file, sec, func->offset)) { | |
298 | WARN("%s(): can't find starting instruction", | |
299 | func->name); | |
300 | return -1; | |
301 | } | |
302 | ||
303 | func_for_each_insn(file, func, insn) | |
304 | if (!insn->func) | |
305 | insn->func = func; | |
306 | } | |
442f04c3 JP |
307 | } |
308 | ||
309 | return 0; | |
310 | } | |
311 | ||
312 | /* | |
313 | * Warnings shouldn't be reported for ignored functions. | |
314 | */ | |
a196e171 | 315 | static void add_ignores(struct objtool_file *file) |
442f04c3 JP |
316 | { |
317 | struct instruction *insn; | |
318 | struct section *sec; | |
319 | struct symbol *func; | |
320 | ||
321 | list_for_each_entry(sec, &file->elf->sections, list) { | |
a196e171 | 322 | list_for_each_entry(func, &sec->symbol_list, list) { |
442f04c3 JP |
323 | if (func->type != STT_FUNC) |
324 | continue; | |
325 | ||
326 | if (!ignore_func(file, func)) | |
327 | continue; | |
328 | ||
74aec058 | 329 | func_for_each_insn(file, func, insn) |
442f04c3 | 330 | insn->visited = true; |
442f04c3 JP |
331 | } |
332 | } | |
333 | } | |
334 | ||
335 | /* | |
336 | * Find the destination instructions for all jumps. | |
337 | */ | |
a196e171 | 338 | static int add_jump_destinations(struct objtool_file *file) |
442f04c3 JP |
339 | { |
340 | struct instruction *insn; | |
341 | struct rela *rela; | |
342 | struct section *dest_sec; | |
343 | unsigned long dest_off; | |
344 | ||
74aec058 | 345 | for_each_insn(file, insn) { |
442f04c3 JP |
346 | if (insn->type != INSN_JUMP_CONDITIONAL && |
347 | insn->type != INSN_JUMP_UNCONDITIONAL) | |
348 | continue; | |
349 | ||
350 | /* skip ignores */ | |
351 | if (insn->visited) | |
352 | continue; | |
353 | ||
354 | rela = find_rela_by_dest_range(insn->sec, insn->offset, | |
355 | insn->len); | |
356 | if (!rela) { | |
357 | dest_sec = insn->sec; | |
358 | dest_off = insn->offset + insn->len + insn->immediate; | |
359 | } else if (rela->sym->type == STT_SECTION) { | |
360 | dest_sec = rela->sym->sec; | |
361 | dest_off = rela->addend + 4; | |
362 | } else if (rela->sym->sec->idx) { | |
363 | dest_sec = rela->sym->sec; | |
364 | dest_off = rela->sym->sym.st_value + rela->addend + 4; | |
365 | } else { | |
366 | /* sibling call */ | |
367 | insn->jump_dest = 0; | |
368 | continue; | |
369 | } | |
370 | ||
74aec058 | 371 | insn->jump_dest = find_insn(file, dest_sec, dest_off); |
442f04c3 JP |
372 | if (!insn->jump_dest) { |
373 | ||
374 | /* | |
375 | * This is a special case where an alt instruction | |
376 | * jumps past the end of the section. These are | |
377 | * handled later in handle_group_alt(). | |
378 | */ | |
379 | if (!strcmp(insn->sec->name, ".altinstr_replacement")) | |
380 | continue; | |
381 | ||
382 | WARN_FUNC("can't find jump dest instruction at %s+0x%lx", | |
383 | insn->sec, insn->offset, dest_sec->name, | |
384 | dest_off); | |
385 | return -1; | |
386 | } | |
387 | } | |
388 | ||
389 | return 0; | |
390 | } | |
391 | ||
392 | /* | |
393 | * Find the destination instructions for all calls. | |
394 | */ | |
a196e171 | 395 | static int add_call_destinations(struct objtool_file *file) |
442f04c3 JP |
396 | { |
397 | struct instruction *insn; | |
398 | unsigned long dest_off; | |
399 | struct rela *rela; | |
400 | ||
74aec058 | 401 | for_each_insn(file, insn) { |
442f04c3 JP |
402 | if (insn->type != INSN_CALL) |
403 | continue; | |
404 | ||
405 | rela = find_rela_by_dest_range(insn->sec, insn->offset, | |
406 | insn->len); | |
407 | if (!rela) { | |
408 | dest_off = insn->offset + insn->len + insn->immediate; | |
409 | insn->call_dest = find_symbol_by_offset(insn->sec, | |
410 | dest_off); | |
411 | if (!insn->call_dest) { | |
412 | WARN_FUNC("can't find call dest symbol at offset 0x%lx", | |
413 | insn->sec, insn->offset, dest_off); | |
414 | return -1; | |
415 | } | |
416 | } else if (rela->sym->type == STT_SECTION) { | |
417 | insn->call_dest = find_symbol_by_offset(rela->sym->sec, | |
418 | rela->addend+4); | |
419 | if (!insn->call_dest || | |
420 | insn->call_dest->type != STT_FUNC) { | |
421 | WARN_FUNC("can't find call dest symbol at %s+0x%x", | |
422 | insn->sec, insn->offset, | |
423 | rela->sym->sec->name, | |
424 | rela->addend + 4); | |
425 | return -1; | |
426 | } | |
427 | } else | |
428 | insn->call_dest = rela->sym; | |
429 | } | |
430 | ||
431 | return 0; | |
432 | } | |
433 | ||
434 | /* | |
435 | * The .alternatives section requires some extra special care, over and above | |
436 | * what other special sections require: | |
437 | * | |
438 | * 1. Because alternatives are patched in-place, we need to insert a fake jump | |
439 | * instruction at the end so that validate_branch() skips all the original | |
440 | * replaced instructions when validating the new instruction path. | |
441 | * | |
442 | * 2. An added wrinkle is that the new instruction length might be zero. In | |
443 | * that case the old instructions are replaced with noops. We simulate that | |
444 | * by creating a fake jump as the only new instruction. | |
445 | * | |
446 | * 3. In some cases, the alternative section includes an instruction which | |
447 | * conditionally jumps to the _end_ of the entry. We have to modify these | |
448 | * jumps' destinations to point back to .text rather than the end of the | |
449 | * entry in .altinstr_replacement. | |
450 | * | |
451 | * 4. It has been requested that we don't validate the !POPCNT feature path | |
452 | * which is a "very very small percentage of machines". | |
453 | */ | |
454 | static int handle_group_alt(struct objtool_file *file, | |
455 | struct special_alt *special_alt, | |
456 | struct instruction *orig_insn, | |
457 | struct instruction **new_insn) | |
458 | { | |
459 | struct instruction *last_orig_insn, *last_new_insn, *insn, *fake_jump; | |
460 | unsigned long dest_off; | |
461 | ||
462 | last_orig_insn = NULL; | |
463 | insn = orig_insn; | |
74aec058 JP |
464 | sec_for_each_insn_from(file, insn) { |
465 | if (insn->offset >= special_alt->orig_off + special_alt->orig_len) | |
442f04c3 JP |
466 | break; |
467 | ||
468 | if (special_alt->skip_orig) | |
469 | insn->type = INSN_NOP; | |
470 | ||
471 | insn->alt_group = true; | |
472 | last_orig_insn = insn; | |
473 | } | |
474 | ||
74aec058 | 475 | if (!next_insn_same_sec(file, last_orig_insn)) { |
442f04c3 JP |
476 | WARN("%s: don't know how to handle alternatives at end of section", |
477 | special_alt->orig_sec->name); | |
478 | return -1; | |
479 | } | |
480 | ||
481 | fake_jump = malloc(sizeof(*fake_jump)); | |
482 | if (!fake_jump) { | |
483 | WARN("malloc failed"); | |
484 | return -1; | |
485 | } | |
486 | memset(fake_jump, 0, sizeof(*fake_jump)); | |
487 | INIT_LIST_HEAD(&fake_jump->alts); | |
488 | fake_jump->sec = special_alt->new_sec; | |
489 | fake_jump->offset = -1; | |
490 | fake_jump->type = INSN_JUMP_UNCONDITIONAL; | |
491 | fake_jump->jump_dest = list_next_entry(last_orig_insn, list); | |
492 | ||
493 | if (!special_alt->new_len) { | |
494 | *new_insn = fake_jump; | |
495 | return 0; | |
496 | } | |
497 | ||
498 | last_new_insn = NULL; | |
499 | insn = *new_insn; | |
74aec058 JP |
500 | sec_for_each_insn_from(file, insn) { |
501 | if (insn->offset >= special_alt->new_off + special_alt->new_len) | |
442f04c3 JP |
502 | break; |
503 | ||
504 | last_new_insn = insn; | |
505 | ||
506 | if (insn->type != INSN_JUMP_CONDITIONAL && | |
507 | insn->type != INSN_JUMP_UNCONDITIONAL) | |
508 | continue; | |
509 | ||
510 | if (!insn->immediate) | |
511 | continue; | |
512 | ||
513 | dest_off = insn->offset + insn->len + insn->immediate; | |
514 | if (dest_off == special_alt->new_off + special_alt->new_len) | |
515 | insn->jump_dest = fake_jump; | |
516 | ||
517 | if (!insn->jump_dest) { | |
518 | WARN_FUNC("can't find alternative jump destination", | |
519 | insn->sec, insn->offset); | |
520 | return -1; | |
521 | } | |
522 | } | |
523 | ||
524 | if (!last_new_insn) { | |
525 | WARN_FUNC("can't find last new alternative instruction", | |
526 | special_alt->new_sec, special_alt->new_off); | |
527 | return -1; | |
528 | } | |
529 | ||
530 | list_add(&fake_jump->list, &last_new_insn->list); | |
531 | ||
532 | return 0; | |
533 | } | |
534 | ||
535 | /* | |
536 | * A jump table entry can either convert a nop to a jump or a jump to a nop. | |
537 | * If the original instruction is a jump, make the alt entry an effective nop | |
538 | * by just skipping the original instruction. | |
539 | */ | |
540 | static int handle_jump_alt(struct objtool_file *file, | |
541 | struct special_alt *special_alt, | |
542 | struct instruction *orig_insn, | |
543 | struct instruction **new_insn) | |
544 | { | |
545 | if (orig_insn->type == INSN_NOP) | |
546 | return 0; | |
547 | ||
548 | if (orig_insn->type != INSN_JUMP_UNCONDITIONAL) { | |
549 | WARN_FUNC("unsupported instruction at jump label", | |
550 | orig_insn->sec, orig_insn->offset); | |
551 | return -1; | |
552 | } | |
553 | ||
554 | *new_insn = list_next_entry(orig_insn, list); | |
555 | return 0; | |
556 | } | |
557 | ||
558 | /* | |
559 | * Read all the special sections which have alternate instructions which can be | |
560 | * patched in or redirected to at runtime. Each instruction having alternate | |
561 | * instruction(s) has them added to its insn->alts list, which will be | |
562 | * traversed in validate_branch(). | |
563 | */ | |
a196e171 | 564 | static int add_special_section_alts(struct objtool_file *file) |
442f04c3 JP |
565 | { |
566 | struct list_head special_alts; | |
567 | struct instruction *orig_insn, *new_insn; | |
568 | struct special_alt *special_alt, *tmp; | |
569 | struct alternative *alt; | |
570 | int ret; | |
571 | ||
572 | ret = special_get_alts(file->elf, &special_alts); | |
573 | if (ret) | |
574 | return ret; | |
575 | ||
576 | list_for_each_entry_safe(special_alt, tmp, &special_alts, list) { | |
577 | alt = malloc(sizeof(*alt)); | |
578 | if (!alt) { | |
579 | WARN("malloc failed"); | |
580 | ret = -1; | |
581 | goto out; | |
582 | } | |
583 | ||
74aec058 JP |
584 | orig_insn = find_insn(file, special_alt->orig_sec, |
585 | special_alt->orig_off); | |
442f04c3 JP |
586 | if (!orig_insn) { |
587 | WARN_FUNC("special: can't find orig instruction", | |
588 | special_alt->orig_sec, special_alt->orig_off); | |
589 | ret = -1; | |
590 | goto out; | |
591 | } | |
592 | ||
593 | new_insn = NULL; | |
594 | if (!special_alt->group || special_alt->new_len) { | |
74aec058 JP |
595 | new_insn = find_insn(file, special_alt->new_sec, |
596 | special_alt->new_off); | |
442f04c3 JP |
597 | if (!new_insn) { |
598 | WARN_FUNC("special: can't find new instruction", | |
599 | special_alt->new_sec, | |
600 | special_alt->new_off); | |
601 | ret = -1; | |
602 | goto out; | |
603 | } | |
604 | } | |
605 | ||
606 | if (special_alt->group) { | |
607 | ret = handle_group_alt(file, special_alt, orig_insn, | |
608 | &new_insn); | |
609 | if (ret) | |
610 | goto out; | |
611 | } else if (special_alt->jump_or_nop) { | |
612 | ret = handle_jump_alt(file, special_alt, orig_insn, | |
613 | &new_insn); | |
614 | if (ret) | |
615 | goto out; | |
616 | } | |
617 | ||
618 | alt->insn = new_insn; | |
619 | list_add_tail(&alt->list, &orig_insn->alts); | |
620 | ||
621 | list_del(&special_alt->list); | |
622 | free(special_alt); | |
623 | } | |
624 | ||
625 | out: | |
626 | return ret; | |
627 | } | |
628 | ||
8133fbb4 JP |
629 | static int add_switch_table(struct objtool_file *file, struct symbol *func, |
630 | struct instruction *insn, struct rela *table, | |
631 | struct rela *next_table) | |
442f04c3 | 632 | { |
8133fbb4 JP |
633 | struct rela *rela = table; |
634 | struct instruction *alt_insn; | |
442f04c3 JP |
635 | struct alternative *alt; |
636 | ||
8133fbb4 JP |
637 | list_for_each_entry_from(rela, &file->rodata->rela->rela_list, list) { |
638 | if (rela == next_table) | |
639 | break; | |
640 | ||
641 | if (rela->sym->sec != insn->sec || | |
642 | rela->addend <= func->offset || | |
643 | rela->addend >= func->offset + func->len) | |
644 | break; | |
645 | ||
646 | alt_insn = find_insn(file, insn->sec, rela->addend); | |
647 | if (!alt_insn) { | |
648 | WARN("%s: can't find instruction at %s+0x%x", | |
649 | file->rodata->rela->name, insn->sec->name, | |
650 | rela->addend); | |
651 | return -1; | |
652 | } | |
653 | ||
654 | alt = malloc(sizeof(*alt)); | |
655 | if (!alt) { | |
656 | WARN("malloc failed"); | |
657 | return -1; | |
658 | } | |
659 | ||
660 | alt->insn = alt_insn; | |
661 | list_add_tail(&alt->list, &insn->alts); | |
662 | } | |
663 | ||
664 | return 0; | |
665 | } | |
666 | ||
667 | static int add_func_switch_tables(struct objtool_file *file, | |
668 | struct symbol *func) | |
669 | { | |
670 | struct instruction *insn, *prev_jump; | |
b49364f3 | 671 | struct rela *text_rela, *rodata_rela, *prev_rela = NULL; |
8133fbb4 JP |
672 | int ret; |
673 | ||
674 | prev_jump = NULL; | |
675 | ||
676 | func_for_each_insn(file, func, insn) { | |
442f04c3 JP |
677 | if (insn->type != INSN_JUMP_DYNAMIC) |
678 | continue; | |
679 | ||
a196e171 JP |
680 | text_rela = find_rela_by_dest_range(insn->sec, insn->offset, |
681 | insn->len); | |
8133fbb4 | 682 | if (!text_rela || text_rela->sym != file->rodata->sym) |
442f04c3 JP |
683 | continue; |
684 | ||
685 | /* common case: jmpq *[addr](,%rax,8) */ | |
8133fbb4 JP |
686 | rodata_rela = find_rela_by_dest(file->rodata, |
687 | text_rela->addend); | |
688 | ||
689 | /* | |
8133fbb4 | 690 | * rare case: jmpq *[addr](%rip) |
7e578441 JP |
691 | * |
692 | * This check is for a rare gcc quirk, currently only seen in | |
693 | * three driver functions in the kernel, only with certain | |
694 | * obscure non-distro configs. | |
695 | * | |
696 | * As part of an optimization, gcc makes a copy of an existing | |
697 | * switch jump table, modifies it, and then hard-codes the jump | |
698 | * (albeit with an indirect jump) to use a single entry in the | |
699 | * table. The rest of the jump table and some of its jump | |
700 | * targets remain as dead code. | |
701 | * | |
702 | * In such a case we can just crudely ignore all unreachable | |
703 | * instruction warnings for the entire object file. Ideally we | |
704 | * would just ignore them for the function, but that would | |
705 | * require redesigning the code quite a bit. And honestly | |
706 | * that's just not worth doing: unreachable instruction | |
707 | * warnings are of questionable value anyway, and this is such | |
708 | * a rare issue. | |
709 | * | |
710 | * kbuild reports: | |
711 | * - https://lkml.kernel.org/r/201603231906.LWcVUpxm%25fengguang.wu@intel.com | |
712 | * - https://lkml.kernel.org/r/201603271114.K9i45biy%25fengguang.wu@intel.com | |
713 | * - https://lkml.kernel.org/r/201603291058.zuJ6ben1%25fengguang.wu@intel.com | |
714 | * | |
715 | * gcc bug: | |
716 | * - https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70604 | |
8133fbb4 | 717 | */ |
7e578441 | 718 | if (!rodata_rela) { |
8133fbb4 | 719 | rodata_rela = find_rela_by_dest(file->rodata, |
a196e171 | 720 | text_rela->addend + 4); |
7e578441 JP |
721 | if (rodata_rela) |
722 | file->ignore_unreachables = true; | |
723 | } | |
8133fbb4 | 724 | |
a196e171 | 725 | if (!rodata_rela) |
442f04c3 JP |
726 | continue; |
727 | ||
8133fbb4 JP |
728 | /* |
729 | * We found a switch table, but we don't know yet how big it | |
730 | * is. Don't add it until we reach the end of the function or | |
731 | * the beginning of another switch table in the same function. | |
732 | */ | |
733 | if (prev_jump) { | |
734 | ret = add_switch_table(file, func, prev_jump, prev_rela, | |
735 | rodata_rela); | |
736 | if (ret) | |
737 | return ret; | |
442f04c3 JP |
738 | } |
739 | ||
8133fbb4 JP |
740 | prev_jump = insn; |
741 | prev_rela = rodata_rela; | |
742 | } | |
442f04c3 | 743 | |
8133fbb4 JP |
744 | if (prev_jump) { |
745 | ret = add_switch_table(file, func, prev_jump, prev_rela, NULL); | |
746 | if (ret) | |
747 | return ret; | |
748 | } | |
749 | ||
750 | return 0; | |
751 | } | |
442f04c3 | 752 | |
8133fbb4 JP |
753 | /* |
754 | * For some switch statements, gcc generates a jump table in the .rodata | |
755 | * section which contains a list of addresses within the function to jump to. | |
756 | * This finds these jump tables and adds them to the insn->alts lists. | |
757 | */ | |
758 | static int add_switch_table_alts(struct objtool_file *file) | |
759 | { | |
760 | struct section *sec; | |
761 | struct symbol *func; | |
762 | int ret; | |
763 | ||
764 | if (!file->rodata || !file->rodata->rela) | |
765 | return 0; | |
766 | ||
767 | list_for_each_entry(sec, &file->elf->sections, list) { | |
768 | list_for_each_entry(func, &sec->symbol_list, list) { | |
769 | if (func->type != STT_FUNC) | |
770 | continue; | |
771 | ||
772 | ret = add_func_switch_tables(file, func); | |
773 | if (ret) | |
774 | return ret; | |
442f04c3 JP |
775 | } |
776 | } | |
777 | ||
778 | return 0; | |
779 | } | |
780 | ||
781 | static int decode_sections(struct objtool_file *file) | |
782 | { | |
783 | int ret; | |
784 | ||
785 | ret = decode_instructions(file); | |
786 | if (ret) | |
787 | return ret; | |
788 | ||
a196e171 | 789 | add_ignores(file); |
442f04c3 | 790 | |
a196e171 | 791 | ret = add_jump_destinations(file); |
442f04c3 JP |
792 | if (ret) |
793 | return ret; | |
794 | ||
a196e171 | 795 | ret = add_call_destinations(file); |
442f04c3 JP |
796 | if (ret) |
797 | return ret; | |
798 | ||
a196e171 | 799 | ret = add_special_section_alts(file); |
442f04c3 JP |
800 | if (ret) |
801 | return ret; | |
802 | ||
a196e171 | 803 | ret = add_switch_table_alts(file); |
442f04c3 JP |
804 | if (ret) |
805 | return ret; | |
806 | ||
807 | return 0; | |
808 | } | |
809 | ||
810 | static bool is_fentry_call(struct instruction *insn) | |
811 | { | |
812 | if (insn->type == INSN_CALL && | |
813 | insn->call_dest->type == STT_NOTYPE && | |
814 | !strcmp(insn->call_dest->name, "__fentry__")) | |
815 | return true; | |
816 | ||
817 | return false; | |
818 | } | |
819 | ||
820 | static bool has_modified_stack_frame(struct instruction *insn) | |
821 | { | |
822 | return (insn->state & STATE_FP_SAVED) || | |
823 | (insn->state & STATE_FP_SETUP); | |
824 | } | |
825 | ||
826 | static bool has_valid_stack_frame(struct instruction *insn) | |
827 | { | |
828 | return (insn->state & STATE_FP_SAVED) && | |
829 | (insn->state & STATE_FP_SETUP); | |
830 | } | |
831 | ||
d8d1b2cb JP |
832 | static unsigned int frame_state(unsigned long state) |
833 | { | |
834 | return (state & (STATE_FP_SAVED | STATE_FP_SETUP)); | |
835 | } | |
836 | ||
442f04c3 JP |
837 | /* |
838 | * Follow the branch starting at the given instruction, and recursively follow | |
839 | * any other branches (jumps). Meanwhile, track the frame pointer state at | |
840 | * each instruction and validate all the rules described in | |
841 | * tools/objtool/Documentation/stack-validation.txt. | |
842 | */ | |
843 | static int validate_branch(struct objtool_file *file, | |
844 | struct instruction *first, unsigned char first_state) | |
845 | { | |
846 | struct alternative *alt; | |
847 | struct instruction *insn; | |
848 | struct section *sec; | |
b1547d31 | 849 | struct symbol *func = NULL; |
442f04c3 | 850 | unsigned char state; |
1bcb58a0 | 851 | int ret; |
442f04c3 JP |
852 | |
853 | insn = first; | |
854 | sec = insn->sec; | |
855 | state = first_state; | |
856 | ||
857 | if (insn->alt_group && list_empty(&insn->alts)) { | |
858 | WARN_FUNC("don't know how to handle branch to middle of alternative instruction group", | |
859 | sec, insn->offset); | |
1bcb58a0 | 860 | return 1; |
442f04c3 JP |
861 | } |
862 | ||
863 | while (1) { | |
b1547d31 JP |
864 | if (file->c_file && insn->func) { |
865 | if (func && func != insn->func) { | |
866 | WARN("%s() falls through to next function %s()", | |
867 | func->name, insn->func->name); | |
868 | return 1; | |
869 | } | |
870 | ||
871 | func = insn->func; | |
872 | } | |
873 | ||
442f04c3 | 874 | if (insn->visited) { |
d8d1b2cb | 875 | if (frame_state(insn->state) != frame_state(state)) { |
442f04c3 JP |
876 | WARN_FUNC("frame pointer state mismatch", |
877 | sec, insn->offset); | |
1bcb58a0 | 878 | return 1; |
442f04c3 JP |
879 | } |
880 | ||
1bcb58a0 | 881 | return 0; |
442f04c3 JP |
882 | } |
883 | ||
442f04c3 JP |
884 | insn->visited = true; |
885 | insn->state = state; | |
886 | ||
887 | list_for_each_entry(alt, &insn->alts, list) { | |
888 | ret = validate_branch(file, alt->insn, state); | |
1bcb58a0 JP |
889 | if (ret) |
890 | return 1; | |
442f04c3 JP |
891 | } |
892 | ||
893 | switch (insn->type) { | |
894 | ||
895 | case INSN_FP_SAVE: | |
896 | if (!nofp) { | |
897 | if (state & STATE_FP_SAVED) { | |
898 | WARN_FUNC("duplicate frame pointer save", | |
899 | sec, insn->offset); | |
1bcb58a0 | 900 | return 1; |
442f04c3 JP |
901 | } |
902 | state |= STATE_FP_SAVED; | |
903 | } | |
904 | break; | |
905 | ||
906 | case INSN_FP_SETUP: | |
907 | if (!nofp) { | |
908 | if (state & STATE_FP_SETUP) { | |
909 | WARN_FUNC("duplicate frame pointer setup", | |
910 | sec, insn->offset); | |
1bcb58a0 | 911 | return 1; |
442f04c3 JP |
912 | } |
913 | state |= STATE_FP_SETUP; | |
914 | } | |
915 | break; | |
916 | ||
917 | case INSN_FP_RESTORE: | |
918 | if (!nofp) { | |
919 | if (has_valid_stack_frame(insn)) | |
920 | state &= ~STATE_FP_SETUP; | |
921 | ||
922 | state &= ~STATE_FP_SAVED; | |
923 | } | |
924 | break; | |
925 | ||
926 | case INSN_RETURN: | |
927 | if (!nofp && has_modified_stack_frame(insn)) { | |
928 | WARN_FUNC("return without frame pointer restore", | |
929 | sec, insn->offset); | |
1bcb58a0 | 930 | return 1; |
442f04c3 | 931 | } |
1bcb58a0 | 932 | return 0; |
442f04c3 JP |
933 | |
934 | case INSN_CALL: | |
935 | if (is_fentry_call(insn)) { | |
936 | state |= STATE_FENTRY; | |
937 | break; | |
938 | } | |
939 | ||
b1e03249 JP |
940 | ret = dead_end_function(file, insn->call_dest); |
941 | if (ret == 1) | |
1bcb58a0 | 942 | return 0; |
b1e03249 | 943 | if (ret == -1) |
1bcb58a0 | 944 | return 1; |
442f04c3 JP |
945 | |
946 | /* fallthrough */ | |
947 | case INSN_CALL_DYNAMIC: | |
948 | if (!nofp && !has_valid_stack_frame(insn)) { | |
949 | WARN_FUNC("call without frame pointer save/setup", | |
950 | sec, insn->offset); | |
1bcb58a0 | 951 | return 1; |
442f04c3 JP |
952 | } |
953 | break; | |
954 | ||
955 | case INSN_JUMP_CONDITIONAL: | |
956 | case INSN_JUMP_UNCONDITIONAL: | |
957 | if (insn->jump_dest) { | |
958 | ret = validate_branch(file, insn->jump_dest, | |
959 | state); | |
1bcb58a0 JP |
960 | if (ret) |
961 | return 1; | |
442f04c3 JP |
962 | } else if (has_modified_stack_frame(insn)) { |
963 | WARN_FUNC("sibling call from callable instruction with changed frame pointer", | |
964 | sec, insn->offset); | |
1bcb58a0 | 965 | return 1; |
442f04c3 JP |
966 | } /* else it's a sibling call */ |
967 | ||
968 | if (insn->type == INSN_JUMP_UNCONDITIONAL) | |
1bcb58a0 | 969 | return 0; |
442f04c3 JP |
970 | |
971 | break; | |
972 | ||
973 | case INSN_JUMP_DYNAMIC: | |
974 | if (list_empty(&insn->alts) && | |
975 | has_modified_stack_frame(insn)) { | |
976 | WARN_FUNC("sibling call from callable instruction with changed frame pointer", | |
977 | sec, insn->offset); | |
1bcb58a0 | 978 | return 1; |
442f04c3 JP |
979 | } |
980 | ||
1bcb58a0 | 981 | return 0; |
442f04c3 JP |
982 | |
983 | case INSN_BUG: | |
1bcb58a0 | 984 | return 0; |
442f04c3 JP |
985 | |
986 | default: | |
987 | break; | |
988 | } | |
989 | ||
74aec058 JP |
990 | insn = next_insn_same_sec(file, insn); |
991 | if (!insn) { | |
442f04c3 | 992 | WARN("%s: unexpected end of section", sec->name); |
1bcb58a0 | 993 | return 1; |
442f04c3 JP |
994 | } |
995 | } | |
996 | ||
1bcb58a0 | 997 | return 0; |
442f04c3 JP |
998 | } |
999 | ||
1000 | static bool is_gcov_insn(struct instruction *insn) | |
1001 | { | |
1002 | struct rela *rela; | |
1003 | struct section *sec; | |
1004 | struct symbol *sym; | |
1005 | unsigned long offset; | |
1006 | ||
1007 | rela = find_rela_by_dest_range(insn->sec, insn->offset, insn->len); | |
1008 | if (!rela) | |
1009 | return false; | |
1010 | ||
1011 | if (rela->sym->type != STT_SECTION) | |
1012 | return false; | |
1013 | ||
1014 | sec = rela->sym->sec; | |
1015 | offset = rela->addend + insn->offset + insn->len - rela->offset; | |
1016 | ||
a196e171 | 1017 | list_for_each_entry(sym, &sec->symbol_list, list) { |
442f04c3 JP |
1018 | if (sym->type != STT_OBJECT) |
1019 | continue; | |
1020 | ||
1021 | if (offset >= sym->offset && offset < sym->offset + sym->len) | |
1022 | return (!memcmp(sym->name, "__gcov0.", 8)); | |
1023 | } | |
1024 | ||
1025 | return false; | |
1026 | } | |
1027 | ||
1028 | static bool is_kasan_insn(struct instruction *insn) | |
1029 | { | |
1030 | return (insn->type == INSN_CALL && | |
1031 | !strcmp(insn->call_dest->name, "__asan_handle_no_return")); | |
1032 | } | |
1033 | ||
1034 | static bool is_ubsan_insn(struct instruction *insn) | |
1035 | { | |
1036 | return (insn->type == INSN_CALL && | |
1037 | !strcmp(insn->call_dest->name, | |
1038 | "__ubsan_handle_builtin_unreachable")); | |
1039 | } | |
1040 | ||
74aec058 JP |
1041 | static bool ignore_unreachable_insn(struct symbol *func, |
1042 | struct instruction *insn) | |
442f04c3 JP |
1043 | { |
1044 | int i; | |
1045 | ||
1046 | if (insn->type == INSN_NOP) | |
1047 | return true; | |
1048 | ||
1049 | if (is_gcov_insn(insn)) | |
1050 | return true; | |
1051 | ||
1052 | /* | |
1053 | * Check if this (or a subsequent) instruction is related to | |
1054 | * CONFIG_UBSAN or CONFIG_KASAN. | |
1055 | * | |
1056 | * End the search at 5 instructions to avoid going into the weeds. | |
1057 | */ | |
1058 | for (i = 0; i < 5; i++) { | |
1059 | ||
1060 | if (is_kasan_insn(insn) || is_ubsan_insn(insn)) | |
1061 | return true; | |
1062 | ||
1063 | if (insn->type == INSN_JUMP_UNCONDITIONAL && insn->jump_dest) { | |
1064 | insn = insn->jump_dest; | |
1065 | continue; | |
1066 | } | |
1067 | ||
74aec058 | 1068 | if (insn->offset + insn->len >= func->offset + func->len) |
442f04c3 JP |
1069 | break; |
1070 | insn = list_next_entry(insn, list); | |
1071 | } | |
1072 | ||
1073 | return false; | |
1074 | } | |
1075 | ||
1076 | static int validate_functions(struct objtool_file *file) | |
1077 | { | |
1078 | struct section *sec; | |
1079 | struct symbol *func; | |
1080 | struct instruction *insn; | |
442f04c3 JP |
1081 | int ret, warnings = 0; |
1082 | ||
1083 | list_for_each_entry(sec, &file->elf->sections, list) { | |
a196e171 | 1084 | list_for_each_entry(func, &sec->symbol_list, list) { |
442f04c3 JP |
1085 | if (func->type != STT_FUNC) |
1086 | continue; | |
1087 | ||
74aec058 | 1088 | insn = find_insn(file, sec, func->offset); |
b1547d31 | 1089 | if (!insn) |
442f04c3 | 1090 | continue; |
442f04c3 JP |
1091 | |
1092 | ret = validate_branch(file, insn, 0); | |
1093 | warnings += ret; | |
1094 | } | |
1095 | } | |
1096 | ||
1097 | list_for_each_entry(sec, &file->elf->sections, list) { | |
a196e171 | 1098 | list_for_each_entry(func, &sec->symbol_list, list) { |
442f04c3 JP |
1099 | if (func->type != STT_FUNC) |
1100 | continue; | |
1101 | ||
74aec058 | 1102 | func_for_each_insn(file, func, insn) { |
442f04c3 JP |
1103 | if (insn->visited) |
1104 | continue; | |
1105 | ||
442f04c3 | 1106 | insn->visited = true; |
7e578441 JP |
1107 | |
1108 | if (file->ignore_unreachables || warnings || | |
1109 | ignore_unreachable_insn(func, insn)) | |
1110 | continue; | |
1111 | ||
1112 | WARN_FUNC("function has unreachable instruction", insn->sec, insn->offset); | |
1113 | warnings++; | |
442f04c3 JP |
1114 | } |
1115 | } | |
1116 | } | |
1117 | ||
1118 | return warnings; | |
1119 | } | |
1120 | ||
1121 | static int validate_uncallable_instructions(struct objtool_file *file) | |
1122 | { | |
1123 | struct instruction *insn; | |
1124 | int warnings = 0; | |
1125 | ||
74aec058 | 1126 | for_each_insn(file, insn) { |
442f04c3 JP |
1127 | if (!insn->visited && insn->type == INSN_RETURN) { |
1128 | WARN_FUNC("return instruction outside of a callable function", | |
1129 | insn->sec, insn->offset); | |
1130 | warnings++; | |
1131 | } | |
1132 | } | |
1133 | ||
1134 | return warnings; | |
1135 | } | |
1136 | ||
1137 | static void cleanup(struct objtool_file *file) | |
1138 | { | |
1139 | struct instruction *insn, *tmpinsn; | |
1140 | struct alternative *alt, *tmpalt; | |
1141 | ||
a196e171 | 1142 | list_for_each_entry_safe(insn, tmpinsn, &file->insn_list, list) { |
442f04c3 JP |
1143 | list_for_each_entry_safe(alt, tmpalt, &insn->alts, list) { |
1144 | list_del(&alt->list); | |
1145 | free(alt); | |
1146 | } | |
1147 | list_del(&insn->list); | |
042ba73f | 1148 | hash_del(&insn->hash); |
442f04c3 JP |
1149 | free(insn); |
1150 | } | |
1151 | elf_close(file->elf); | |
1152 | } | |
1153 | ||
1154 | const char * const check_usage[] = { | |
1155 | "objtool check [<options>] file.o", | |
1156 | NULL, | |
1157 | }; | |
1158 | ||
1159 | int cmd_check(int argc, const char **argv) | |
1160 | { | |
1161 | struct objtool_file file; | |
1162 | int ret, warnings = 0; | |
1163 | ||
1164 | const struct option options[] = { | |
1165 | OPT_BOOLEAN('f', "no-fp", &nofp, "Skip frame pointer validation"), | |
1166 | OPT_END(), | |
1167 | }; | |
1168 | ||
1169 | argc = parse_options(argc, argv, options, check_usage, 0); | |
1170 | ||
1171 | if (argc != 1) | |
1172 | usage_with_options(check_usage, options); | |
1173 | ||
1174 | objname = argv[0]; | |
1175 | ||
1176 | file.elf = elf_open(objname); | |
1177 | if (!file.elf) { | |
1178 | fprintf(stderr, "error reading elf file %s\n", objname); | |
1179 | return 1; | |
1180 | } | |
1181 | ||
a196e171 | 1182 | INIT_LIST_HEAD(&file.insn_list); |
042ba73f | 1183 | hash_init(file.insn_hash); |
7e578441 JP |
1184 | file.whitelist = find_section_by_name(file.elf, "__func_stack_frame_non_standard"); |
1185 | file.rodata = find_section_by_name(file.elf, ".rodata"); | |
1186 | file.ignore_unreachables = false; | |
b1547d31 | 1187 | file.c_file = find_section_by_name(file.elf, ".comment"); |
442f04c3 JP |
1188 | |
1189 | ret = decode_sections(&file); | |
1190 | if (ret < 0) | |
1191 | goto out; | |
1192 | warnings += ret; | |
1193 | ||
1194 | ret = validate_functions(&file); | |
1195 | if (ret < 0) | |
1196 | goto out; | |
1197 | warnings += ret; | |
1198 | ||
1199 | ret = validate_uncallable_instructions(&file); | |
1200 | if (ret < 0) | |
1201 | goto out; | |
1202 | warnings += ret; | |
1203 | ||
1204 | out: | |
1205 | cleanup(&file); | |
1206 | ||
1207 | /* ignore warnings for now until we get all the code cleaned up */ | |
1208 | if (ret || warnings) | |
1209 | return 0; | |
1210 | return 0; | |
1211 | } |