backtrace.cpp revision 9b12d53b1a180bb7c6c946649254e6f23e6ca04d 
1/*
2 * Copyright (C) 2012 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#include <stddef.h>
18#include <stdlib.h>
19#include <string.h>
20#include <stdio.h>
21#include <time.h>
22#include <errno.h>
23#include <limits.h>
24#include <dirent.h>
25#include <unistd.h>
26#include <sys/types.h>
27#include <sys/ptrace.h>
28
29#include <backtrace/Backtrace.h>
30#include <UniquePtr.h>
31
32#include "backtrace.h"
33
34#include "utility.h"
35
36static void dump_process_header(log_t* log, pid_t pid) {
37  char path[PATH_MAX];
38  char procnamebuf[1024];
39  char* procname = NULL;
40  FILE* fp;
41
42  snprintf(path, sizeof(path), "/proc/%d/cmdline", pid);
43  if ((fp = fopen(path, "r"))) {
44    procname = fgets(procnamebuf, sizeof(procnamebuf), fp);
45    fclose(fp);
46  }
47
48  time_t t = time(NULL);
49  struct tm tm;
50  localtime_r(&t, &tm);
51  char timestr[64];
52  strftime(timestr, sizeof(timestr), "%F %T", &tm);
53  _LOG(log, logtype::BACKTRACE, "\n\n----- pid %d at %s -----\n", pid, timestr);
54
55  if (procname) {
56    _LOG(log, logtype::BACKTRACE, "Cmd line: %s\n", procname);
57  }
58  _LOG(log, logtype::BACKTRACE, "ABI: '%s'\n", ABI_STRING);
59}
60
61static void dump_process_footer(log_t* log, pid_t pid) {
62  _LOG(log, logtype::BACKTRACE, "\n----- end %d -----\n", pid);
63}
64
65static void dump_thread(
66    log_t* log, pid_t tid, bool attached, bool* detach_failed, int* total_sleep_time_usec) {
67  char path[PATH_MAX];
68  char threadnamebuf[1024];
69  char* threadname = NULL;
70  FILE* fp;
71
72  snprintf(path, sizeof(path), "/proc/%d/comm", tid);
73  if ((fp = fopen(path, "r"))) {
74    threadname = fgets(threadnamebuf, sizeof(threadnamebuf), fp);
75    fclose(fp);
76    if (threadname) {
77      size_t len = strlen(threadname);
78      if (len && threadname[len - 1] == '\n') {
79          threadname[len - 1] = '\0';
80      }
81    }
82  }
83
84  _LOG(log, logtype::BACKTRACE, "\n\"%s\" sysTid=%d\n", threadname ? threadname : "<unknown>", tid);
85
86  if (!attached && ptrace(PTRACE_ATTACH, tid, 0, 0) < 0) {
87    _LOG(log, logtype::BACKTRACE, "Could not attach to thread: %s\n", strerror(errno));
88    return;
89  }
90
91  wait_for_stop(tid, total_sleep_time_usec);
92
93  UniquePtr<Backtrace> backtrace(Backtrace::Create(tid, BACKTRACE_CURRENT_THREAD));
94  if (backtrace->Unwind(0)) {
95    dump_backtrace_to_log(backtrace.get(), log, "  ");
96  }
97
98  if (!attached && ptrace(PTRACE_DETACH, tid, 0, 0) != 0) {
99    _LOG(log, logtype::ERROR, "ptrace detach from %d failed: %s\n", tid, strerror(errno));
100    *detach_failed = true;
101  }
102}
103
104void dump_backtrace(int fd, int amfd, pid_t pid, pid_t tid, bool* detach_failed,
105                    int* total_sleep_time_usec) {
106  log_t log;
107  log.tfd = fd;
108  log.amfd = amfd;
109
110  dump_process_header(&log, pid);
111  dump_thread(&log, tid, true, detach_failed, total_sleep_time_usec);
112
113  char task_path[64];
114  snprintf(task_path, sizeof(task_path), "/proc/%d/task", pid);
115  DIR* d = opendir(task_path);
116  if (d != NULL) {
117    struct dirent* de = NULL;
118    while ((de = readdir(d)) != NULL) {
119      if (!strcmp(de->d_name, ".") || !strcmp(de->d_name, "..")) {
120        continue;
121      }
122
123      char* end;
124      pid_t new_tid = strtoul(de->d_name, &end, 10);
125      if (*end || new_tid == tid) {
126        continue;
127      }
128
129      dump_thread(&log, new_tid, false, detach_failed, total_sleep_time_usec);
130    }
131    closedir(d);
132  }
133
134  dump_process_footer(&log, pid);
135}
136
137void dump_backtrace_to_log(Backtrace* backtrace, log_t* log, const char* prefix) {
138  for (size_t i = 0; i < backtrace->NumFrames(); i++) {
139    _LOG(log, logtype::BACKTRACE, "%s%s\n", prefix, backtrace->FormatFrameData(i).c_str());
140  }
141}
142