Register signal handlers after shutdown pipe is setup.

chrome/browser/browser_main_posix.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/browser_main_posix.h"
 
 #include <errno.h>
 #include <limits.h>
 #include <signal.h>
 #include <sys/resource.h>
 #include <unistd.h>
 
 #include <string>
 
 #include "base/command_line.h"
 #include "base/eintr_wrapper.h"
 #include "base/logging.h"
 #include "base/string_number_conversions.h"
 #include "chrome/browser/defaults.h"
 #include "chrome/browser/ui/browser_list.h"
 #include "chrome/common/chrome_switches.h"
 #include "content/browser/browser_thread.h"
 
 #if defined(TOOLKIT_USES_GTK) && !defined(OS_CHROMEOS)
 #include "chrome/browser/printing/print_dialog_gtk.h"
 #endif
 
 namespace {
 
 // See comment in |PreEarlyInitialization()|, where sigaction is called.

[viettrungluu, 2011/07/21 18:00:20]

Update this comment.

[oshima, 2011/07/22 01:36:30]

SIGCHLDHandler was moved back to PreEarlyInitialization

 void SIGCHLDHandler(int signal) {
 }
 
 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_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 |PreEarlyInitialization()|, where sigaction is called.

[viettrungluu, 2011/07/21 18:00:20]

Ditto, etc.

[oshima, 2011/07/22 01:36:30]

Done.

 void SIGHUPHandler(int signal) {
   RAW_CHECK(signal == SIGHUP);
   GracefulShutdownHandler(signal);
 }
 
 // See comment in |PreEarlyInitialization()|, where sigaction is called.
 void SIGINTHandler(int signal) {
   RAW_CHECK(signal == SIGINT);
   GracefulShutdownHandler(signal);
 }
@@ skipping 111 matching lines @@
   } else {
     PLOG(INFO) << "Failed to get file descriptor limit";
   }
 }
 
 }  // namespace
 
 // BrowserMainPartsPosix -------------------------------------------------------
 
 void BrowserMainPartsPosix::PreEarlyInitialization() {
-  // 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(sigaction(SIGCHLD, &action, NULL) == 0);
-
-  // 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.
-  memset(&action, 0, sizeof(action));
-  action.sa_handler = SIGTERMHandler;
-  CHECK(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(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(sigaction(SIGHUP, &action, NULL) == 0);
-
   const std::string fd_limit_string =
       parsed_command_line().GetSwitchValueASCII(
           switches::kFileDescriptorLimit);
   int fd_limit = 0;
   if (!fd_limit_string.empty()) {
     base::StringToInt(fd_limit_string, &fd_limit);
   }
 #if defined(OS_MACOSX)
   // We use quite a few file descriptors for our IPC, and the default limit on
   // the Mac is low (256), so bump it up if there is no explicit override.
@@ skipping 25 matching lines @@
     g_shutdown_pipe_write_fd = pipefd[1];
     const size_t kShutdownDetectorThreadStackSize = 4096;
     // 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 AFTER shutodwn pipe is setup because

[viettrungluu, 2011/07/21 18:00:20]

s/shutodwn/shutdown/

+  // it may be called right away after handler is set.
+
+  // We need to accept SIGCHLD, even though our handler is a no-op because

[viettrungluu, 2011/07/21 18:00:20]

We can presumably set up the SIGCHLD handler earlier, right? It's only the
signal handlers which call GracefulShutdownHandler() which need to be set up
after the pipe.

[oshima, 2011/07/22 01:36:30]

You're right. I moved SIGCHLDHandler back to PreEarlyInitialization.

+  // otherwise we cannot wait on children. (According to POSIX 2001.)
+  struct sigaction action;
+  memset(&action, 0, sizeof(action));
+  action.sa_handler = SIGCHLDHandler;
+  CHECK(sigaction(SIGCHLD, &action, NULL) == 0);
+
+  // 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.
+  memset(&action, 0, sizeof(action));
+  action.sa_handler = SIGTERMHandler;
+  CHECK(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(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(sigaction(SIGHUP, &action, NULL) == 0);
 
 #if defined(TOOLKIT_USES_GTK) && !defined(OS_CHROMEOS)
   printing::PrintingContextCairo::SetCreatePrintDialogFunction(
       &PrintDialogGtk::CreatePrintDialog);
 #endif
 }