Merge pull request #2982 from atom/ctrl-c

Quit gracefully when Ctrl-C is pressed

atom/browser/atom_browser_main_parts.cc

@@ -52,6 +52,13 @@ void AtomBrowserMainParts::RegisterDestructionCallback(
   destruction_callbacks_.push_back(callback);
 }
 
+void AtomBrowserMainParts::PreEarlyInitialization() {
+  brightray::BrowserMainParts::PreEarlyInitialization();
+#if defined(OS_POSIX)
+  HandleSIGCHLD();
+#endif
+}
+
 void AtomBrowserMainParts::PostEarlyInitialization() {
   brightray::BrowserMainParts::PostEarlyInitialization();
 
@@ -112,6 +119,13 @@ void AtomBrowserMainParts::PreMainMessageLoopRun() {
 #endif
 }
 
+void AtomBrowserMainParts::PostMainMessageLoopStart() {
+  brightray::BrowserMainParts::PostMainMessageLoopStart();
+#if defined(OS_POSIX)
+  HandleShutdownSignals();
+#endif
+}
+
 void AtomBrowserMainParts::PostMainMessageLoopRun() {
   brightray::BrowserMainParts::PostMainMessageLoopRun();
 

atom/browser/atom_browser_main_parts.h

@@ -39,8 +39,10 @@ class AtomBrowserMainParts : public brightray::BrowserMainParts {
 
  protected:
   // content::BrowserMainParts:
+  void PreEarlyInitialization() override;
   void PostEarlyInitialization() override;
   void PreMainMessageLoopRun() override;
+  void PostMainMessageLoopStart() override;
   void PostMainMessageLoopRun() override;
 #if defined(OS_MACOSX)
   void PreMainMessageLoopStart() override;
@@ -48,6 +50,12 @@ class AtomBrowserMainParts : public brightray::BrowserMainParts {
 #endif
 
  private:
+#if defined(OS_POSIX)
+  // Set signal handlers.
+  void HandleSIGCHLD();
+  void HandleShutdownSignals();
+#endif
+
   // A fake BrowserProcess object that used to feed the source code from chrome.
   scoped_ptr<BrowserProcess> fake_browser_process_;
 

atom/browser/atom_browser_main_parts_posix.cc

@@ -0,0 +1,225 @@
+// Copyright (c) 2015 GitHub, Inc.
+// Use of this source code is governed by the MIT license that can be
+// found in the LICENSE file.
+
+// Most code came from: chrome/browser/chrome_browser_main_posix.cc.
+
+#include "atom/browser/atom_browser_main_parts.h"
+
+#include <errno.h>
+#include <limits.h>
+#include <pthread.h>
+#include <signal.h>
+#include <sys/resource.h>
+#include <unistd.h>
+
+#include "atom/browser/browser.h"
+#include "base/posix/eintr_wrapper.h"
+#include "content/public/browser/browser_thread.h"
+
+using content::BrowserThread;
+
+namespace atom {
+
+namespace {
+
+// See comment in |PreEarlyInitialization()|, where sigaction is called.
+void SIGCHLDHandler(int signal) {
+}
+
+// The OSX fork() implementation can crash in the child process before
+// fork() returns.  In that case, the shutdown pipe will still be
+// shared with the parent process.  To prevent child crashes from
+// causing parent shutdowns, |g_pipe_pid| is the pid for the process
+// which registered |g_shutdown_pipe_write_fd|.
+// See <http://crbug.com/175341>.
+pid_t g_pipe_pid = -1;
+int g_shutdown_pipe_write_fd = -1;
+int g_shutdown_pipe_read_fd = -1;
+
+// Common code between SIG{HUP, INT, TERM}Handler.
+void GracefulShutdownHandler(int signal) {
+  // Reinstall the default handler.  We had one shot at graceful shutdown.
+  struct sigaction action;
+  memset(&action, 0, sizeof(action));
+  action.sa_handler = SIG_DFL;
+  RAW_CHECK(sigaction(signal, &action, NULL) == 0);
+
+  RAW_CHECK(g_pipe_pid == getpid());
+  RAW_CHECK(g_shutdown_pipe_write_fd != -1);
+  RAW_CHECK(g_shutdown_pipe_read_fd != -1);
+  size_t bytes_written = 0;
+  do {
+    int rv = HANDLE_EINTR(
+        write(g_shutdown_pipe_write_fd,
+              reinterpret_cast<const char*>(&signal) + bytes_written,
+              sizeof(signal) - bytes_written));
+    RAW_CHECK(rv >= 0);
+    bytes_written += rv;
+  } while (bytes_written < sizeof(signal));
+}
+
+// See comment in |PostMainMessageLoopStart()|, where sigaction is called.
+void SIGHUPHandler(int signal) {
+  RAW_CHECK(signal == SIGHUP);
+  GracefulShutdownHandler(signal);
+}
+
+// See comment in |PostMainMessageLoopStart()|, where sigaction is called.
+void SIGINTHandler(int signal) {
+  RAW_CHECK(signal == SIGINT);
+  GracefulShutdownHandler(signal);
+}
+
+// See comment in |PostMainMessageLoopStart()|, where sigaction is called.
+void SIGTERMHandler(int signal) {
+  RAW_CHECK(signal == SIGTERM);
+  GracefulShutdownHandler(signal);
+}
+
+class ShutdownDetector : public base::PlatformThread::Delegate {
+ public:
+  explicit ShutdownDetector(int shutdown_fd);
+
+  void ThreadMain() override;
+
+ private:
+  const int shutdown_fd_;
+
+  DISALLOW_COPY_AND_ASSIGN(ShutdownDetector);
+};
+
+ShutdownDetector::ShutdownDetector(int shutdown_fd)
+    : shutdown_fd_(shutdown_fd) {
+  CHECK_NE(shutdown_fd_, -1);
+}
+
+// These functions are used to help us diagnose crash dumps that happen
+// during the shutdown process.
+NOINLINE void ShutdownFDReadError() {
+  // Ensure function isn't optimized away.
+  asm("");
+  sleep(UINT_MAX);
+}
+
+NOINLINE void ShutdownFDClosedError() {
+  // Ensure function isn't optimized away.
+  asm("");
+  sleep(UINT_MAX);
+}
+
+NOINLINE void ExitPosted() {
+  // Ensure function isn't optimized away.
+  asm("");
+  sleep(UINT_MAX);
+}
+
+void ShutdownDetector::ThreadMain() {
+  base::PlatformThread::SetName("CrShutdownDetector");
+
+  int signal;
+  size_t bytes_read = 0;
+  ssize_t ret;
+  do {
+    ret = HANDLE_EINTR(
+        read(shutdown_fd_,
+             reinterpret_cast<char*>(&signal) + bytes_read,
+             sizeof(signal) - bytes_read));
+    if (ret < 0) {
+      NOTREACHED() << "Unexpected error: " << strerror(errno);
+      ShutdownFDReadError();
+      break;
+    } else if (ret == 0) {
+      NOTREACHED() << "Unexpected closure of shutdown pipe.";
+      ShutdownFDClosedError();
+      break;
+    }
+    bytes_read += ret;
+  } while (bytes_read < sizeof(signal));
+  VLOG(1) << "Handling shutdown for signal " << signal << ".";
+  base::Closure task =
+      base::Bind(&Browser::Quit, base::Unretained(Browser::Get()));
+
+  if (!BrowserThread::PostTask(BrowserThread::UI, FROM_HERE, task)) {
+    // Without a UI thread to post the exit task to, there aren't many
+    // options.  Raise the signal again.  The default handler will pick it up
+    // and cause an ungraceful exit.
+    RAW_LOG(WARNING, "No UI thread, exiting ungracefully.");
+    kill(getpid(), signal);
+
+    // The signal may be handled on another thread.  Give that a chance to
+    // happen.
+    sleep(3);
+
+    // We really should be dead by now.  For whatever reason, we're not. Exit
+    // immediately, with the exit status set to the signal number with bit 8
+    // set.  On the systems that we care about, this exit status is what is
+    // normally used to indicate an exit by this signal's default handler.
+    // This mechanism isn't a de jure standard, but even in the worst case, it
+    // should at least result in an immediate exit.
+    RAW_LOG(WARNING, "Still here, exiting really ungracefully.");
+    _exit(signal | (1 << 7));
+  }
+  ExitPosted();
+}
+
+}  // namespace
+
+void AtomBrowserMainParts::HandleSIGCHLD() {
+  // We need to accept SIGCHLD, even though our handler is a no-op because
+  // otherwise we cannot wait on children. (According to POSIX 2001.)
+  struct sigaction action;
+  memset(&action, 0, sizeof(action));
+  action.sa_handler = SIGCHLDHandler;
+  CHECK_EQ(sigaction(SIGCHLD, &action, NULL), 0);
+}
+
+void AtomBrowserMainParts::HandleShutdownSignals() {
+  int pipefd[2];
+  int ret = pipe(pipefd);
+  if (ret < 0) {
+    PLOG(DFATAL) << "Failed to create pipe";
+  } else {
+    g_pipe_pid = getpid();
+    g_shutdown_pipe_read_fd = pipefd[0];
+    g_shutdown_pipe_write_fd = pipefd[1];
+#if !defined(ADDRESS_SANITIZER) && !defined(KEEP_SHADOW_STACKS)
+    const size_t kShutdownDetectorThreadStackSize = PTHREAD_STACK_MIN * 2;
+#else
+    // ASan instrumentation and -finstrument-functions (used for keeping the
+    // shadow stacks) bloat the stack frames, so we need to increase the stack
+    // size to avoid hitting the guard page.
+    const size_t kShutdownDetectorThreadStackSize = PTHREAD_STACK_MIN * 4;
+#endif
+    // TODO(viettrungluu,willchan): crbug.com/29675 - This currently leaks, so
+    // if you change this, you'll probably need to change the suppression.
+    if (!base::PlatformThread::CreateNonJoinable(
+            kShutdownDetectorThreadStackSize,
+            new ShutdownDetector(g_shutdown_pipe_read_fd))) {
+      LOG(DFATAL) << "Failed to create shutdown detector task.";
+    }
+  }
+  // Setup signal handlers for shutdown AFTER shutdown pipe is setup because
+  // it may be called right away after handler is set.
+
+  // If adding to this list of signal handlers, note the new signal probably
+  // needs to be reset in child processes. See
+  // base/process_util_posix.cc:LaunchProcess.
+
+  // We need to handle SIGTERM, because that is how many POSIX-based distros ask
+  // processes to quit gracefully at shutdown time.
+  struct sigaction action;
+  memset(&action, 0, sizeof(action));
+  action.sa_handler = SIGTERMHandler;
+  CHECK_EQ(sigaction(SIGTERM, &action, NULL), 0);
+  // Also handle SIGINT - when the user terminates the browser via Ctrl+C. If
+  // the browser process is being debugged, GDB will catch the SIGINT first.
+  action.sa_handler = SIGINTHandler;
+  CHECK_EQ(sigaction(SIGINT, &action, NULL), 0);
+  // And SIGHUP, for when the terminal disappears. On shutdown, many Linux
+  // distros send SIGHUP, SIGTERM, and then SIGKILL.
+  action.sa_handler = SIGHUPHandler;
+  CHECK_EQ(sigaction(SIGHUP, &action, NULL), 0);
+}
+
+}  // namespace atom

atom/browser/browser.cc

@@ -16,7 +16,8 @@ namespace atom {
 
 Browser::Browser()
     : is_quiting_(false),
-      is_ready_(false) {
+      is_ready_(false),
+      is_shutdown_(false) {
   WindowList::AddObserver(this);
 }
 
@@ -30,6 +31,9 @@ Browser* Browser::Get() {
 }
 
 void Browser::Quit() {
+  if (is_quiting_)
+    return;
+
   is_quiting_ = HandleBeforeQuit();
   if (!is_quiting_)
     return;
@@ -42,9 +46,13 @@ void Browser::Quit() {
 }
 
 void Browser::Shutdown() {
-  FOR_EACH_OBSERVER(BrowserObserver, observers_, OnQuit());
+  if (is_shutdown_)
+    return;
 
+  is_shutdown_ = true;
   is_quiting_ = true;
+
+  FOR_EACH_OBSERVER(BrowserObserver, observers_, OnQuit());
   base::MessageLoop::current()->PostTask(
       FROM_HERE, base::MessageLoop::QuitWhenIdleClosure());
 }
@@ -121,6 +129,9 @@ void Browser::ClientCertificateSelector(
 }
 
 void Browser::NotifyAndShutdown() {
+  if (is_shutdown_)
+    return;
+
   bool prevent_default = false;
   FOR_EACH_OBSERVER(BrowserObserver, observers_, OnWillQuit(&prevent_default));
 

atom/browser/browser.h

@@ -159,6 +159,9 @@ class Browser : public WindowListObserver {
   // Whether "ready" event has been emitted.
   bool is_ready_;
 
+  // The browse is being shutdown.
+  bool is_shutdown_;
+
   std::string version_override_;
   std::string name_override_;
 

filenames.gypi

@@ -125,6 +125,7 @@
       'atom/browser/atom_browser_main_parts.cc',
       'atom/browser/atom_browser_main_parts.h',
       'atom/browser/atom_browser_main_parts_mac.mm',
+      'atom/browser/atom_browser_main_parts_posix.cc',
       'atom/browser/atom_javascript_dialog_manager.cc',
       'atom/browser/atom_javascript_dialog_manager.h',
       'atom/browser/atom_quota_permission_context.cc',