backtrace.cpp revision 20303f856f1f1cdb5af58af0b116b8c598f0ea5c 
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#include "utility.h"
34
35static void dump_process_header(log_t* log, pid_t pid) {
36  char path[PATH_MAX];
37  char procnamebuf[1024];
38  char* procname = NULL;
39  FILE* fp;
40
41  snprintf(path, sizeof(path), "/proc/%d/cmdline", pid);
42  if ((fp = fopen(path, "r"))) {
43    procname = fgets(procnamebuf, sizeof(procnamebuf), fp);
44    fclose(fp);
45  }
46
47  time_t t = time(NULL);
48  struct tm tm;
49  localtime_r(&t, &tm);
50  char timestr[64];
51  strftime(timestr, sizeof(timestr), "%F %T", &tm);
52  _LOG(log, SCOPE_AT_FAULT, "\n\n----- pid %d at %s -----\n", pid, timestr);
53
54  if (procname) {
55    _LOG(log, SCOPE_AT_FAULT, "Cmd line: %s\n", procname);
56  }
57}
58
59static void dump_process_footer(log_t* log, pid_t pid) {
60  _LOG(log, SCOPE_AT_FAULT, "\n----- end %d -----\n", pid);
61}
62
63static void dump_thread(
64    log_t* log, pid_t tid, bool attached, bool* detach_failed, int* total_sleep_time_usec) {
65  char path[PATH_MAX];
66  char threadnamebuf[1024];
67  char* threadname = NULL;
68  FILE* fp;
69
70  snprintf(path, sizeof(path), "/proc/%d/comm", tid);
71  if ((fp = fopen(path, "r"))) {
72    threadname = fgets(threadnamebuf, sizeof(threadnamebuf), fp);
73    fclose(fp);
74    if (threadname) {
75      size_t len = strlen(threadname);
76      if (len && threadname[len - 1] == '\n') {
77          threadname[len - 1] = '\0';
78      }
79    }
80  }
81
82  _LOG(log, SCOPE_AT_FAULT, "\n\"%s\" sysTid=%d\n", threadname ? threadname : "<unknown>", tid);
83
84  if (!attached && ptrace(PTRACE_ATTACH, tid, 0, 0) < 0) {
85    _LOG(log, SCOPE_AT_FAULT, "Could not attach to thread: %s\n", strerror(errno));
86    return;
87  }
88
89  wait_for_stop(tid, total_sleep_time_usec);
90
91  UniquePtr<Backtrace> backtrace(Backtrace::Create(tid, BACKTRACE_CURRENT_THREAD));
92  if (backtrace->Unwind(0)) {
93    dump_backtrace_to_log(backtrace.get(), log, SCOPE_AT_FAULT, "  ");
94  }
95
96  if (!attached && ptrace(PTRACE_DETACH, tid, 0, 0) != 0) {
97    LOG("ptrace detach from %d failed: %s\n", tid, strerror(errno));
98    *detach_failed = true;
99  }
100}
101
102void dump_backtrace(int fd, int amfd, pid_t pid, pid_t tid, bool* detach_failed,
103                    int* total_sleep_time_usec) {
104  log_t log;
105  log.tfd = fd;
106  log.amfd = amfd;
107  log.quiet = true;
108
109  dump_process_header(&log, pid);
110  dump_thread(&log, tid, true, detach_failed, total_sleep_time_usec);
111
112  char task_path[64];
113  snprintf(task_path, sizeof(task_path), "/proc/%d/task", pid);
114  DIR* d = opendir(task_path);
115  if (d != NULL) {
116    struct dirent* de = NULL;
117    while ((de = readdir(d)) != NULL) {
118      if (!strcmp(de->d_name, ".") || !strcmp(de->d_name, "..")) {
119        continue;
120      }
121
122      char* end;
123      pid_t new_tid = strtoul(de->d_name, &end, 10);
124      if (*end || new_tid == tid) {
125        continue;
126      }
127
128      dump_thread(&log, new_tid, false, detach_failed, total_sleep_time_usec);
129    }
130    closedir(d);
131  }
132
133  dump_process_footer(&log, pid);
134}
135
136void dump_backtrace_to_log(Backtrace* backtrace, log_t* log,
137                           int scope_flags, const char* prefix) {
138  for (size_t i = 0; i < backtrace->NumFrames(); i++) {
139    _LOG(log, scope_flags, "%s%s\n", prefix, backtrace->FormatFrameData(i).c_str());
140  }
141}
142