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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 
dump_process_header(log_t * log,pid_t pid)36 static 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 
dump_process_footer(log_t * log,pid_t pid)61 static void dump_process_footer(log_t* log, pid_t pid) {
62   _LOG(log, logtype::BACKTRACE, "\n----- end %d -----\n", pid);
63 }
64 
dump_thread(log_t * log,pid_t tid,bool attached,bool * detach_failed,int * total_sleep_time_usec)65 static 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   if (!attached && wait_for_sigstop(tid, total_sleep_time_usec, detach_failed) == -1) {
92     return;
93   }
94 
95   UniquePtr<Backtrace> backtrace(Backtrace::Create(tid, BACKTRACE_CURRENT_THREAD));
96   if (backtrace->Unwind(0)) {
97     dump_backtrace_to_log(backtrace.get(), log, "  ");
98   }
99 
100   if (!attached && ptrace(PTRACE_DETACH, tid, 0, 0) != 0) {
101     _LOG(log, logtype::ERROR, "ptrace detach from %d failed: %s\n", tid, strerror(errno));
102     *detach_failed = true;
103   }
104 }
105 
dump_backtrace(int fd,int amfd,pid_t pid,pid_t tid,bool * detach_failed,int * total_sleep_time_usec)106 void dump_backtrace(int fd, int amfd, pid_t pid, pid_t tid, bool* detach_failed,
107                     int* total_sleep_time_usec) {
108   log_t log;
109   log.tfd = fd;
110   log.amfd = amfd;
111 
112   dump_process_header(&log, pid);
113   dump_thread(&log, tid, true, detach_failed, total_sleep_time_usec);
114 
115   char task_path[64];
116   snprintf(task_path, sizeof(task_path), "/proc/%d/task", pid);
117   DIR* d = opendir(task_path);
118   if (d != NULL) {
119     struct dirent* de = NULL;
120     while ((de = readdir(d)) != NULL) {
121       if (!strcmp(de->d_name, ".") || !strcmp(de->d_name, "..")) {
122         continue;
123       }
124 
125       char* end;
126       pid_t new_tid = strtoul(de->d_name, &end, 10);
127       if (*end || new_tid == tid) {
128         continue;
129       }
130 
131       dump_thread(&log, new_tid, false, detach_failed, total_sleep_time_usec);
132     }
133     closedir(d);
134   }
135 
136   dump_process_footer(&log, pid);
137 }
138 
dump_backtrace_to_log(Backtrace * backtrace,log_t * log,const char * prefix)139 void dump_backtrace_to_log(Backtrace* backtrace, log_t* log, const char* prefix) {
140   for (size_t i = 0; i < backtrace->NumFrames(); i++) {
141     _LOG(log, logtype::BACKTRACE, "%s%s\n", prefix, backtrace->FormatFrameData(i).c_str());
142   }
143 }
144