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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 <stdbool.h>
     19 #include <stdlib.h>
     20 #include <string.h>
     21 #include <stdio.h>
     22 #include <time.h>
     23 #include <errno.h>
     24 #include <limits.h>
     25 #include <dirent.h>
     26 #include <unistd.h>
     27 #include <sys/types.h>
     28 #include <sys/ptrace.h>
     29 
     30 #include <corkscrew/backtrace.h>
     31 
     32 #include "tombstone.h"
     33 #include "utility.h"
     34 
     35 #define STACK_DEPTH 32
     36 
     37 static void dump_process_header(log_t* log, pid_t pid) {
     38     char path[PATH_MAX];
     39     char procnamebuf[1024];
     40     char* procname = NULL;
     41     FILE* fp;
     42 
     43     snprintf(path, sizeof(path), "/proc/%d/cmdline", pid);
     44     if ((fp = fopen(path, "r"))) {
     45         procname = fgets(procnamebuf, sizeof(procnamebuf), fp);
     46         fclose(fp);
     47     }
     48 
     49     time_t t = time(NULL);
     50     struct tm tm;
     51     localtime_r(&t, &tm);
     52     char timestr[64];
     53     strftime(timestr, sizeof(timestr), "%F %T", &tm);
     54     _LOG(log, SCOPE_AT_FAULT, "\n\n----- pid %d at %s -----\n", pid, timestr);
     55 
     56     if (procname) {
     57         _LOG(log, SCOPE_AT_FAULT, "Cmd line: %s\n", procname);
     58     }
     59 }
     60 
     61 static void dump_process_footer(log_t* log, pid_t pid) {
     62     _LOG(log, SCOPE_AT_FAULT, "\n----- end %d -----\n", pid);
     63 }
     64 
     65 static void dump_thread(log_t* log, pid_t tid, ptrace_context_t* context, bool attached,
     66         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, SCOPE_AT_FAULT, "\n\"%s\" sysTid=%d\n",
     85             threadname ? threadname : "<unknown>", tid);
     86 
     87     if (!attached && ptrace(PTRACE_ATTACH, tid, 0, 0) < 0) {
     88         _LOG(log, SCOPE_AT_FAULT, "Could not attach to thread: %s\n", strerror(errno));
     89         return;
     90     }
     91 
     92     wait_for_stop(tid, total_sleep_time_usec);
     93 
     94     backtrace_frame_t backtrace[STACK_DEPTH];
     95     ssize_t frames = unwind_backtrace_ptrace(tid, context, backtrace, 0, STACK_DEPTH);
     96     if (frames <= 0) {
     97         _LOG(log, SCOPE_AT_FAULT, "Could not obtain stack trace for thread.\n");
     98     } else {
     99         backtrace_symbol_t backtrace_symbols[STACK_DEPTH];
    100         get_backtrace_symbols_ptrace(context, backtrace, frames, backtrace_symbols);
    101         for (size_t i = 0; i < (size_t)frames; i++) {
    102             char line[MAX_BACKTRACE_LINE_LENGTH];
    103             format_backtrace_line(i, &backtrace[i], &backtrace_symbols[i],
    104                     line, MAX_BACKTRACE_LINE_LENGTH);
    105             _LOG(log, SCOPE_AT_FAULT, "  %s\n", line);
    106         }
    107         free_backtrace_symbols(backtrace_symbols, frames);
    108     }
    109 
    110     if (!attached && ptrace(PTRACE_DETACH, tid, 0, 0) != 0) {
    111         LOG("ptrace detach from %d failed: %s\n", tid, strerror(errno));
    112         *detach_failed = true;
    113     }
    114 }
    115 
    116 void dump_backtrace(int fd, int amfd, pid_t pid, pid_t tid, bool* detach_failed,
    117         int* total_sleep_time_usec) {
    118     log_t log;
    119     log.tfd = fd;
    120     log.amfd = amfd;
    121     log.quiet = true;
    122 
    123     ptrace_context_t* context = load_ptrace_context(tid);
    124     dump_process_header(&log, pid);
    125     dump_thread(&log, tid, context, true, detach_failed, total_sleep_time_usec);
    126 
    127     char task_path[64];
    128     snprintf(task_path, sizeof(task_path), "/proc/%d/task", pid);
    129     DIR* d = opendir(task_path);
    130     if (d != NULL) {
    131         struct dirent* de = NULL;
    132         while ((de = readdir(d)) != NULL) {
    133             if (!strcmp(de->d_name, ".") || !strcmp(de->d_name, "..")) {
    134                 continue;
    135             }
    136 
    137             char* end;
    138             pid_t new_tid = strtoul(de->d_name, &end, 10);
    139             if (*end || new_tid == tid) {
    140                 continue;
    141             }
    142 
    143             dump_thread(&log, new_tid, context, false, detach_failed, total_sleep_time_usec);
    144         }
    145         closedir(d);
    146     }
    147 
    148     dump_process_footer(&log, pid);
    149     free_ptrace_context(context);
    150 }
    151