stack_trace_android.cc revision 5821806d5e7f356e8fa4b058a389a808ea183019 
1// Copyright (c) 2012 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#include "base/debug/stack_trace.h"
6
7#include <signal.h>
8#include <sys/types.h>
9#include <unistd.h>
10
11#include "base/logging.h"
12
13namespace base {
14namespace debug {
15
16bool EnableInProcessStackDumping() {
17  // When running in an application, our code typically expects SIGPIPE
18  // to be ignored.  Therefore, when testing that same code, it should run
19  // with SIGPIPE ignored as well.
20  // TODO(phajdan.jr): De-duplicate this SIGPIPE code.
21  struct sigaction action;
22  memset(&action, 0, sizeof(action));
23  action.sa_handler = SIG_IGN;
24  sigemptyset(&action.sa_mask);
25  return (sigaction(SIGPIPE, &action, NULL) == 0);
26}
27
28StackTrace::StackTrace() {
29}
30
31// Sends fake SIGSTKFLT signals to let the Android linker and debuggerd dump
32// stack. See inlined comments and Android bionic/linker/debugger.c and
33// system/core/debuggerd/debuggerd.c for details.
34void StackTrace::PrintBacktrace() const {
35  // Get the current handler of SIGSTKFLT for later use.
36  sighandler_t sig_handler = signal(SIGSTKFLT, SIG_DFL);
37  signal(SIGSTKFLT, sig_handler);
38
39  // The Android linker will handle this signal and send a stack dumping request
40  // to debuggerd which will ptrace_attach this process. Before returning from
41  // the signal handler, the linker sets the signal handler to SIG_IGN.
42  kill(gettid(), SIGSTKFLT);
43
44  // Because debuggerd will wait for the process to be stopped by the actual
45  // signal in crashing scenarios, signal is sent again to met the expectation.
46  // Debuggerd will dump stack into the system log and /data/tombstones/ files.
47  // NOTE: If this process runs in the interactive shell, it will be put
48  // in the background. To resume it in the foreground, use 'fg' command.
49  kill(gettid(), SIGSTKFLT);
50
51  // Restore the signal handler so that this method can work the next time.
52  signal(SIGSTKFLT, sig_handler);
53}
54
55void StackTrace::OutputToStream(std::ostream* os) const {
56  NOTIMPLEMENTED();
57}
58
59}  // namespace debug
60}  // namespace base
61