android_webview/common/aw_crash_handler.cc

   1 // Copyright 2014 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 "android_webview/common/aw_crash_handler.h"
   6
   7 #include <android/log.h>
   8 #include <signal.h>
   9
  10 #include "base/logging.h"
  11
  12 namespace {
  13
  14 const int kExceptionSignals[] = {
  15   SIGSEGV, SIGABRT, SIGFPE, SIGILL, SIGBUS
  16 };
  17
  18 struct sigaction old_handlers[arraysize(kExceptionSignals)];
  19
  20 bool crash_handler_registered;
  21
  22 std::string g_crash_msg;
  23
  24 const char* g_crash_msg_ptr;  // Avoid invoking STL magic in a signal handler.
  25
  26 void AwExceptionHandler(int sig, siginfo_t* info, void* uc) {
  27   if (g_crash_msg_ptr != NULL)
  28     __android_log_write(ANDROID_LOG_ERROR, "chromium", g_crash_msg_ptr);
  29
  30   // We served our purpose. Now restore the old crash handlers. If the embedder
  31   // did register a custom crash handler, it will be invoked by the kernel after
  32   // this function returns. Otherwise, this will end up invoking the default
  33   // signal disposition.
  34   for (uint32_t i = 0; i < arraysize(kExceptionSignals); ++i) {
  35     if (sigaction(kExceptionSignals[i], &old_handlers[i], NULL) == -1) {
  36       signal(kExceptionSignals[i], SIG_DFL);
  37     }
  38   }
  39 }
  40
  41 }  // namespace
  42
  43 namespace android_webview {
  44 namespace crash_handler {
  45
  46 void RegisterCrashHandler(const std::string& version) {
  47   if (crash_handler_registered) {
  48     NOTREACHED();
  49     return;
  50   }
  51
  52   g_crash_msg = "### WebView crash. " + version;
  53   g_crash_msg_ptr = g_crash_msg.c_str();
  54
  55   // Fail if unable to store all the old handlers.
  56   for (uint32_t i = 0; i < arraysize(kExceptionSignals); ++i) {
  57     if (sigaction(kExceptionSignals[i], NULL, &old_handlers[i]) == -1) {
  58       LOG(ERROR) << "Error while trying to retrieve old handler for signal "
  59                  << kExceptionSignals[i] << ")";
  60       return;
  61     }
  62   }
  63
  64   struct sigaction sa;
  65   memset(&sa, 0, sizeof(sa));
  66   sigemptyset(&sa.sa_mask);
  67
  68   for (uint32_t i = 0; i < arraysize(kExceptionSignals); ++i)
  69     sigaddset(&sa.sa_mask, kExceptionSignals[i]);
  70
  71   sa.sa_sigaction = AwExceptionHandler;
  72   sa.sa_flags = SA_ONSTACK | SA_SIGINFO;
  73
  74   for (uint32_t i = 0; i < arraysize(kExceptionSignals); ++i) {
  75     if (sigaction(kExceptionSignals[i], &sa, NULL) == -1) {
  76       // At this point it is impractical to back out changes, and so failure to
  77       // install a signal is intentionally ignored.
  78       LOG(ERROR) << "Error while overriding handler for signal "
  79                  << kExceptionSignals[i];
  80     }
  81   }
  82
  83   crash_handler_registered = true;
  84 }
  85
  86 }  // namespace crash_handler
  87 }  // namespace android_webview