| // Copyright 2014 The Chromium OS 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 "chromeos/asynchronous_signal_handler.h" |
| |
| #include <signal.h> |
| #include <sys/types.h> |
| #include <unistd.h> |
| |
| #include <base/files/file_util.h> |
| #include <base/logging.h> |
| #include <base/message_loop/message_loop.h> |
| |
| namespace { |
| const int kInvalidDescriptor = -1; |
| } // namespace |
| |
| namespace chromeos { |
| |
| AsynchronousSignalHandler::AsynchronousSignalHandler() |
| : fd_watcher_(new base::MessageLoopForIO::FileDescriptorWatcher), |
| descriptor_(kInvalidDescriptor) { |
| CHECK_EQ(sigemptyset(&signal_mask_), 0) << "Failed to initialize signal mask"; |
| CHECK_EQ(sigemptyset(&saved_signal_mask_), 0) |
| << "Failed to initialize signal mask"; |
| } |
| |
| AsynchronousSignalHandler::~AsynchronousSignalHandler() { |
| if (descriptor_ != kInvalidDescriptor) { |
| fd_watcher_->StopWatchingFileDescriptor(); |
| |
| if (close(descriptor_) != 0) |
| PLOG(WARNING) << "Failed to close file descriptor"; |
| |
| descriptor_ = kInvalidDescriptor; |
| CHECK_EQ(0, sigprocmask(SIG_SETMASK, &saved_signal_mask_, nullptr)); |
| } |
| } |
| |
| void AsynchronousSignalHandler::Init() { |
| CHECK_EQ(kInvalidDescriptor, descriptor_); |
| CHECK_EQ(0, sigprocmask(SIG_BLOCK, &signal_mask_, &saved_signal_mask_)); |
| descriptor_ = |
| signalfd(descriptor_, &signal_mask_, SFD_CLOEXEC | SFD_NONBLOCK); |
| CHECK_NE(kInvalidDescriptor, descriptor_); |
| CHECK(base::MessageLoopForIO::current()->WatchFileDescriptor( |
| descriptor_, |
| true, |
| base::MessageLoopForIO::WATCH_READ, |
| fd_watcher_.get(), |
| this)) |
| << "Watching shutdown pipe failed."; |
| } |
| |
| void AsynchronousSignalHandler::RegisterHandler(int signal, |
| const SignalHandler& callback) { |
| registered_callbacks_[signal] = callback; |
| CHECK_EQ(0, sigaddset(&signal_mask_, signal)); |
| UpdateSignals(); |
| } |
| |
| void AsynchronousSignalHandler::UnregisterHandler(int signal) { |
| Callbacks::iterator callback_it = registered_callbacks_.find(signal); |
| if (callback_it != registered_callbacks_.end()) { |
| registered_callbacks_.erase(callback_it); |
| ResetSignal(signal); |
| } |
| } |
| |
| void AsynchronousSignalHandler::OnFileCanReadWithoutBlocking(int fd) { |
| struct signalfd_siginfo info; |
| while (base::ReadFromFD(fd, reinterpret_cast<char*>(&info), sizeof(info))) { |
| int signal = info.ssi_signo; |
| Callbacks::iterator callback_it = registered_callbacks_.find(signal); |
| if (callback_it == registered_callbacks_.end()) { |
| LOG(WARNING) << "Unable to find a signal handler for signal: " << signal; |
| // Can happen if a signal has been called multiple time, and the callback |
| // asked to be unregistered the first time. |
| continue; |
| } |
| const SignalHandler& callback = callback_it->second; |
| bool must_unregister = callback.Run(info); |
| if (must_unregister) { |
| UnregisterHandler(signal); |
| } |
| } |
| } |
| |
| void AsynchronousSignalHandler::OnFileCanWriteWithoutBlocking(int fd) { |
| NOTREACHED(); |
| } |
| |
| void AsynchronousSignalHandler::ResetSignal(int signal) { |
| CHECK_EQ(0, sigdelset(&signal_mask_, signal)); |
| UpdateSignals(); |
| } |
| |
| void AsynchronousSignalHandler::UpdateSignals() { |
| if (descriptor_ != kInvalidDescriptor) { |
| CHECK_EQ(0, sigprocmask(SIG_SETMASK, &saved_signal_mask_, nullptr)); |
| CHECK_EQ(0, sigprocmask(SIG_BLOCK, &signal_mask_, nullptr)); |
| CHECK_EQ(descriptor_, |
| signalfd(descriptor_, &signal_mask_, SFD_CLOEXEC | SFD_NONBLOCK)); |
| } |
| } |
| |
| } // namespace chromeos |