Index: chrome/app/shutdown_signal_handlers_posix.cc |
diff --git a/chrome/app/shutdown_signal_handlers_posix.cc b/chrome/app/shutdown_signal_handlers_posix.cc |
new file mode 100644 |
index 0000000000000000000000000000000000000000..5c7ffd922082d5b8d6b47ca544326bf93102a273 |
--- /dev/null |
+++ b/chrome/app/shutdown_signal_handlers_posix.cc |
@@ -0,0 +1,226 @@ |
+// Copyright 2017 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/app/shutdown_signal_handlers_posix.h" |
+ |
+#include <limits.h> |
+#include <signal.h> |
+#include <string.h> |
+#include <unistd.h> |
+ |
+#include "base/callback.h" |
+#include "base/debug/leak_annotations.h" |
+#include "base/logging.h" |
+#include "base/macros.h" |
+#include "base/posix/eintr_wrapper.h" |
+#include "base/single_thread_task_runner.h" |
+#include "base/threading/platform_thread.h" |
+#include "base/threading/thread_task_runner_handle.h" |
+ |
+namespace { |
+ |
+// The OSX fork() implementation can crash in the child process before |
James Cook
2017/03/01 18:24:38
This code is a straight cut-paste from chrome_brow
|
+// 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 != -1); |
+ RAW_CHECK(g_shutdown_pipe_write_fd != -1); |
+ RAW_CHECK(g_shutdown_pipe_read_fd != -1); |
+ RAW_CHECK(g_pipe_pid == getpid()); |
+ 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)); |
+} |
+ |
+void SIGHUPHandler(int signal) { |
+ RAW_CHECK(signal == SIGHUP); |
+ GracefulShutdownHandler(signal); |
+} |
+ |
+void SIGINTHandler(int signal) { |
+ RAW_CHECK(signal == SIGINT); |
+ GracefulShutdownHandler(signal); |
+} |
+ |
+void SIGTERMHandler(int signal) { |
+ RAW_CHECK(signal == SIGTERM); |
+ GracefulShutdownHandler(signal); |
+} |
+ |
+// Runs a thread that invokes a callback when a termination signal handler |
+// is invoked. Uses a pipe to wait for the signal handler to run. |
+class ShutdownDetector : public base::PlatformThread::Delegate { |
+ public: |
+ ShutdownDetector( |
+ int shutdown_fd, |
+ const base::Closure& shutdown_callback, |
+ const scoped_refptr<base::SingleThreadTaskRunner>& task_runner); |
James Cook
2017/03/01 18:24:38
Added the task runner and callback.
|
+ ~ShutdownDetector() override; |
James Cook
2017/03/01 18:24:38
Added destructor.
|
+ |
+ // base::PlatformThread::Delegate: |
+ void ThreadMain() override; |
+ |
+ private: |
+ const int shutdown_fd_; |
+ const base::Closure shutdown_callback_; |
+ const scoped_refptr<base::SingleThreadTaskRunner> task_runner_; |
+ |
+ DISALLOW_COPY_AND_ASSIGN(ShutdownDetector); |
+}; |
+ |
+ShutdownDetector::ShutdownDetector( |
+ int shutdown_fd, |
+ const base::Closure& shutdown_callback, |
+ const scoped_refptr<base::SingleThreadTaskRunner>& task_runner) |
+ : shutdown_fd_(shutdown_fd), |
+ shutdown_callback_(shutdown_callback), |
+ task_runner_(task_runner) { |
+ CHECK_NE(shutdown_fd_, -1); |
+ CHECK(!shutdown_callback.is_null()); |
+ CHECK(task_runner_); |
+} |
+ |
+ShutdownDetector::~ShutdownDetector() {} |
+ |
+// 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 << "."; |
+ |
+ if (!task_runner_->PostTask(FROM_HERE, shutdown_callback_)) { |
James Cook
2017/03/01 18:24:38
Used it here.
|
+ // Without a valid task runner 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 valid task runner, 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 InstallShutdownSignalHandlers( |
+ const base::Closure& shutdown_callback, |
+ const scoped_refptr<base::SingleThreadTaskRunner>& task_runner) { |
+ int pipefd[2]; |
+ int ret = pipe(pipefd); |
+ if (ret < 0) { |
+ PLOG(DFATAL) << "Failed to create pipe"; |
+ return; |
James Cook
2017/03/01 18:24:38
Added early exit to reduce indenting.
|
+ } |
+ 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 |
+ ShutdownDetector* detector = new ShutdownDetector( |
James Cook
2017/03/01 18:24:38
Used local variable so I could add the leak annota
|
+ g_shutdown_pipe_read_fd, shutdown_callback, task_runner); |
+ // PlatformThread does not delete its delegate. |
+ ANNOTATE_LEAKING_OBJECT_PTR(detector); |
+ if (!base::PlatformThread::CreateNonJoinable(kShutdownDetectorThreadStackSize, |
+ detector)) { |
+ 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(sigaction(SIGTERM, &action, nullptr) == 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, nullptr) == 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, nullptr) == 0); |
+} |