2 * Copyright (c) 2013 Luca Clementi <luca.clementi@gmail.com>
3 * Copyright (c) 2013-2017 The strace developers.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. The name of the author may not be used to endorse or promote products
14 * derived from this software without specific prior written permission.
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30 #include <libunwind-ptrace.h>
32 #ifdef _LARGEFILE64_SOURCE
34 # define fopen_for_input fopen64
36 # define fopen_for_input fopen
39 # define fopen_for_input fopen
42 #define DPRINTF(F, A, ...) \
45 error_msg("[unwind(" A ")] " F, __VA_ARGS__); \
49 * Keep a sorted array of cache entries,
50 * so that we can binary search through it.
55 * 7fabbb09b000-7fabbb09f000 r-xp 00179000 fc:00 1180246 /lib/libc-2.11.1.so
57 * start_addr is 0x7fabbb09b000
58 * end_addr is 0x7fabbb09f000
59 * mmap_offset is 0x179000
60 * binary_filename is "/lib/libc-2.11.1.so"
62 unsigned long start_addr;
63 unsigned long end_addr;
64 unsigned long mmap_offset;
65 char *binary_filename;
69 * Type used in stacktrace walker
71 typedef void (*call_action_fn)(void *data,
72 const char *binary_filename,
73 const char *symbol_name,
74 unw_word_t function_offset,
75 unsigned long true_offset);
76 typedef void (*error_action_fn)(void *data,
78 unsigned long true_offset);
81 * Type used in stacktrace capturing
93 static void queue_print(struct queue_t *queue);
94 static void delete_mmap_cache(struct tcb *tcp, const char *caller);
96 static unw_addr_space_t libunwind_as;
97 static unsigned int mmap_cache_generation;
102 libunwind_as = unw_create_addr_space(&_UPT_accessors, 0);
104 error_msg_and_die("failed to create address space for stack tracing");
105 unw_set_caching_policy(libunwind_as, UNW_CACHE_GLOBAL);
109 unwind_tcb_init(struct tcb *tcp)
111 if (tcp->libunwind_ui)
114 tcp->libunwind_ui = _UPT_create(tcp->pid);
115 if (!tcp->libunwind_ui)
116 perror_msg_and_die("_UPT_create");
118 tcp->queue = xmalloc(sizeof(*tcp->queue));
119 tcp->queue->head = NULL;
120 tcp->queue->tail = NULL;
124 unwind_tcb_fin(struct tcb *tcp)
126 queue_print(tcp->queue);
130 delete_mmap_cache(tcp, __func__);
132 _UPT_destroy(tcp->libunwind_ui);
133 tcp->libunwind_ui = NULL;
137 * caching of /proc/ID/maps for each process to speed up stack tracing
139 * The cache must be refreshed after syscalls that affect memory mappings,
140 * e.g. mmap, mprotect, munmap, execve.
143 build_mmap_cache(struct tcb *tcp)
146 struct mmap_cache_t *cache_head;
147 /* start with a small dynamically-allocated array and then expand it */
148 size_t cur_array_size = 10;
149 char filename[sizeof("/proc/4294967296/maps")];
150 char buffer[PATH_MAX + 80];
152 unw_flush_cache(libunwind_as, 0, 0);
154 sprintf(filename, "/proc/%u/maps", tcp->pid);
155 fp = fopen_for_input(filename, "r");
157 perror_msg("fopen: %s", filename);
161 cache_head = xcalloc(cur_array_size, sizeof(*cache_head));
163 while (fgets(buffer, sizeof(buffer), fp) != NULL) {
164 struct mmap_cache_t *entry;
165 unsigned long start_addr, end_addr, mmap_offset;
167 char binary_path[sizeof(buffer)];
169 if (sscanf(buffer, "%lx-%lx %*c%*c%c%*c %lx %*x:%*x %*d %[^\n]",
170 &start_addr, &end_addr, &exec_bit,
171 &mmap_offset, binary_path) != 5)
174 /* ignore mappings that have no PROT_EXEC bit set */
178 if (end_addr < start_addr) {
179 error_msg("%s: unrecognized file format", filename);
184 * sanity check to make sure that we're storing
185 * non-overlapping regions in ascending order
187 if (tcp->mmap_cache_size > 0) {
188 entry = &cache_head[tcp->mmap_cache_size - 1];
189 if (entry->start_addr == start_addr &&
190 entry->end_addr == end_addr) {
191 /* duplicate entry, e.g. [vsyscall] */
194 if (start_addr <= entry->start_addr ||
195 start_addr < entry->end_addr) {
196 error_msg("%s: overlapping memory region",
202 if (tcp->mmap_cache_size >= cur_array_size) {
204 cache_head = xreallocarray(cache_head, cur_array_size,
205 sizeof(*cache_head));
208 entry = &cache_head[tcp->mmap_cache_size];
209 entry->start_addr = start_addr;
210 entry->end_addr = end_addr;
211 entry->mmap_offset = mmap_offset;
212 entry->binary_filename = xstrdup(binary_path);
213 tcp->mmap_cache_size++;
216 tcp->mmap_cache = cache_head;
217 tcp->mmap_cache_generation = mmap_cache_generation;
219 DPRINTF("tgen=%u, ggen=%u, tcp=%p, cache=%p",
221 tcp->mmap_cache_generation,
222 mmap_cache_generation,
223 tcp, tcp->mmap_cache);
226 /* deleting the cache */
228 delete_mmap_cache(struct tcb *tcp, const char *caller)
232 DPRINTF("tgen=%u, ggen=%u, tcp=%p, cache=%p, caller=%s",
234 tcp->mmap_cache_generation,
235 mmap_cache_generation,
236 tcp, tcp->mmap_cache, caller);
238 for (i = 0; i < tcp->mmap_cache_size; i++) {
239 free(tcp->mmap_cache[i].binary_filename);
240 tcp->mmap_cache[i].binary_filename = NULL;
242 free(tcp->mmap_cache);
243 tcp->mmap_cache = NULL;
244 tcp->mmap_cache_size = 0;
248 rebuild_cache_if_invalid(struct tcb *tcp, const char *caller)
250 if ((tcp->mmap_cache_generation != mmap_cache_generation)
252 delete_mmap_cache(tcp, caller);
254 if (!tcp->mmap_cache)
255 build_mmap_cache(tcp);
257 if (!tcp->mmap_cache || !tcp->mmap_cache_size)
264 unwind_cache_invalidate(struct tcb *tcp)
266 #if SUPPORTED_PERSONALITIES > 1
267 if (tcp->currpers != DEFAULT_PERSONALITY) {
268 /* disable strack trace */
272 mmap_cache_generation++;
273 DPRINTF("tgen=%u, ggen=%u, tcp=%p, cache=%p", "increment",
274 tcp->mmap_cache_generation,
275 mmap_cache_generation,
281 get_symbol_name(unw_cursor_t *cursor, char **name,
282 size_t *size, unw_word_t *offset)
285 int rc = unw_get_proc_name(cursor, *name, *size, offset);
288 if (rc != -UNW_ENOMEM) {
293 *name = xreallocarray(*name, 2, *size);
299 print_stack_frame(struct tcb *tcp,
300 call_action_fn call_action,
301 error_action_fn error_action,
303 unw_cursor_t *cursor,
305 size_t *symbol_name_size)
309 int upper = (int) tcp->mmap_cache_size - 1;
311 if (unw_get_reg(cursor, UNW_REG_IP, &ip) < 0) {
312 perror_msg("Can't walk the stack of process %d", tcp->pid);
316 while (lower <= upper) {
317 struct mmap_cache_t *cur_mmap_cache;
318 int mid = (upper + lower) / 2;
320 cur_mmap_cache = &tcp->mmap_cache[mid];
322 if (ip >= cur_mmap_cache->start_addr &&
323 ip < cur_mmap_cache->end_addr) {
324 unsigned long true_offset;
325 unw_word_t function_offset;
327 get_symbol_name(cursor, symbol_name, symbol_name_size,
329 true_offset = ip - cur_mmap_cache->start_addr +
330 cur_mmap_cache->mmap_offset;
332 cur_mmap_cache->binary_filename,
337 } else if (ip < cur_mmap_cache->start_addr)
344 * there is a bug in libunwind >= 1.0
345 * after a set_tid_address syscall
346 * unw_get_reg returns IP == 0
349 error_action(data, "unexpected_backtracing_error", ip);
357 stacktrace_walk(struct tcb *tcp,
358 call_action_fn call_action,
359 error_action_fn error_action,
363 size_t symbol_name_size = 40;
367 if (!tcp->mmap_cache)
368 error_msg_and_die("bug: mmap_cache is NULL");
369 if (tcp->mmap_cache_size == 0)
370 error_msg_and_die("bug: mmap_cache is empty");
372 symbol_name = xmalloc(symbol_name_size);
374 if (unw_init_remote(&cursor, libunwind_as, tcp->libunwind_ui) < 0)
375 perror_msg_and_die("Can't initiate libunwind");
377 for (stack_depth = 0; stack_depth < 256; ++stack_depth) {
378 if (print_stack_frame(tcp, call_action, error_action, data,
379 &cursor, &symbol_name, &symbol_name_size) < 0)
381 if (unw_step(&cursor) <= 0)
384 if (stack_depth >= 256)
385 error_action(data, "too many stack frames", 0);
391 * printing an entry in stack to stream or buffer
394 * we want to keep the format used by backtrace_symbols from the glibc
396 * ./a.out() [0x40063d]
397 * ./a.out() [0x4006bb]
398 * ./a.out() [0x4006c6]
399 * /lib64/libc.so.6(__libc_start_main+0xed) [0x7fa2f8a5976d]
400 * ./a.out() [0x400569]
402 #define STACK_ENTRY_SYMBOL_FMT \
403 " > %s(%s+0x%lx) [0x%lx]\n", \
406 (unsigned long) function_offset, \
408 #define STACK_ENTRY_NOSYMBOL_FMT \
409 " > %s() [0x%lx]\n", \
410 binary_filename, true_offset
411 #define STACK_ENTRY_BUG_FMT \
413 #define STACK_ENTRY_ERROR_WITH_OFFSET_FMT \
414 " > %s [0x%lx]\n", error, true_offset
415 #define STACK_ENTRY_ERROR_FMT \
419 print_call_cb(void *dummy,
420 const char *binary_filename,
421 const char *symbol_name,
422 unw_word_t function_offset,
423 unsigned long true_offset)
425 if (symbol_name && (symbol_name[0] != '\0'))
426 tprintf(STACK_ENTRY_SYMBOL_FMT);
427 else if (binary_filename)
428 tprintf(STACK_ENTRY_NOSYMBOL_FMT);
430 tprintf(STACK_ENTRY_BUG_FMT, __func__);
436 print_error_cb(void *dummy,
438 unsigned long true_offset)
441 tprintf(STACK_ENTRY_ERROR_WITH_OFFSET_FMT);
443 tprintf(STACK_ENTRY_ERROR_FMT);
449 sprint_call_or_error(const char *binary_filename,
450 const char *symbol_name,
451 unw_word_t function_offset,
452 unsigned long true_offset,
455 char *output_line = NULL;
459 n = asprintf(&output_line, STACK_ENTRY_SYMBOL_FMT);
460 else if (binary_filename)
461 n = asprintf(&output_line, STACK_ENTRY_NOSYMBOL_FMT);
464 ? asprintf(&output_line, STACK_ENTRY_ERROR_WITH_OFFSET_FMT)
465 : asprintf(&output_line, STACK_ENTRY_ERROR_FMT);
467 n = asprintf(&output_line, STACK_ENTRY_BUG_FMT, __func__);
470 error_msg_and_die("error in asprintf");
479 queue_put(struct queue_t *queue,
480 const char *binary_filename,
481 const char *symbol_name,
482 unw_word_t function_offset,
483 unsigned long true_offset,
488 call = xmalloc(sizeof(*call));
489 call->output_line = sprint_call_or_error(binary_filename,
500 queue->tail->next = call;
506 queue_put_call(void *queue,
507 const char *binary_filename,
508 const char *symbol_name,
509 unw_word_t function_offset,
510 unsigned long true_offset)
521 queue_put_error(void *queue,
525 queue_put(queue, NULL, NULL, 0, ip, error);
529 queue_print(struct queue_t *queue)
531 struct call_t *call, *tmp;
540 tprints(tmp->output_line);
543 free(tmp->output_line);
544 tmp->output_line = NULL;
554 unwind_print_stacktrace(struct tcb *tcp)
556 #if SUPPORTED_PERSONALITIES > 1
557 if (tcp->currpers != DEFAULT_PERSONALITY) {
558 /* disable strack trace */
562 if (tcp->queue->head) {
563 DPRINTF("tcp=%p, queue=%p", "queueprint", tcp, tcp->queue->head);
564 queue_print(tcp->queue);
565 } else if (rebuild_cache_if_invalid(tcp, __func__)) {
566 DPRINTF("tcp=%p, queue=%p", "stackprint", tcp, tcp->queue->head);
567 stacktrace_walk(tcp, print_call_cb, print_error_cb, NULL);
575 unwind_capture_stacktrace(struct tcb *tcp)
577 #if SUPPORTED_PERSONALITIES > 1
578 if (tcp->currpers != DEFAULT_PERSONALITY) {
579 /* disable strack trace */
583 if (tcp->queue->head)
584 error_msg_and_die("bug: unprinted entries in queue");
586 if (rebuild_cache_if_invalid(tcp, __func__)) {
587 stacktrace_walk(tcp, queue_put_call, queue_put_error,
589 DPRINTF("tcp=%p, queue=%p", "captured", tcp, tcp->queue->head);