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108 lines
3.6 KiB
108 lines
3.6 KiB
// Copyright 2014 The Chromium OS Authors. All rights reserved. |
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// Use of this source code is governed by a BSD-style license that can be |
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// found in the LICENSE file. |
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#include "brillo/asynchronous_signal_handler.h" |
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#include <signal.h> |
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#include <sys/types.h> |
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#include <unistd.h> |
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#include <base/bind.h> |
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#include <base/files/file_util.h> |
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#include <base/logging.h> |
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#include <base/message_loop/message_loop.h> |
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#include <base/posix/eintr_wrapper.h> |
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namespace { |
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const int kInvalidDescriptor = -1; |
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} // namespace |
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namespace brillo { |
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AsynchronousSignalHandler::AsynchronousSignalHandler() |
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: descriptor_(kInvalidDescriptor) { |
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CHECK_EQ(sigemptyset(&signal_mask_), 0) << "Failed to initialize signal mask"; |
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CHECK_EQ(sigemptyset(&saved_signal_mask_), 0) |
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<< "Failed to initialize signal mask"; |
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} |
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AsynchronousSignalHandler::~AsynchronousSignalHandler() { |
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if (descriptor_ != kInvalidDescriptor) { |
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MessageLoop::current()->CancelTask(fd_watcher_task_); |
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if (IGNORE_EINTR(close(descriptor_)) != 0) |
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PLOG(WARNING) << "Failed to close file descriptor"; |
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descriptor_ = kInvalidDescriptor; |
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CHECK_EQ(0, sigprocmask(SIG_SETMASK, &saved_signal_mask_, nullptr)); |
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} |
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} |
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void AsynchronousSignalHandler::Init() { |
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CHECK_EQ(kInvalidDescriptor, descriptor_); |
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CHECK_EQ(0, sigprocmask(SIG_BLOCK, &signal_mask_, &saved_signal_mask_)); |
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descriptor_ = |
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signalfd(descriptor_, &signal_mask_, SFD_CLOEXEC | SFD_NONBLOCK); |
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CHECK_NE(kInvalidDescriptor, descriptor_); |
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fd_watcher_task_ = MessageLoop::current()->WatchFileDescriptor( |
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FROM_HERE, |
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descriptor_, |
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MessageLoop::WatchMode::kWatchRead, |
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true, |
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base::Bind(&AsynchronousSignalHandler::OnFileCanReadWithoutBlocking, |
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base::Unretained(this))); |
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CHECK(fd_watcher_task_ != MessageLoop::kTaskIdNull) |
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<< "Watching shutdown pipe failed."; |
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} |
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void AsynchronousSignalHandler::RegisterHandler(int signal, |
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const SignalHandler& callback) { |
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registered_callbacks_[signal] = callback; |
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CHECK_EQ(0, sigaddset(&signal_mask_, signal)); |
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UpdateSignals(); |
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} |
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void AsynchronousSignalHandler::UnregisterHandler(int signal) { |
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Callbacks::iterator callback_it = registered_callbacks_.find(signal); |
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if (callback_it != registered_callbacks_.end()) { |
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registered_callbacks_.erase(callback_it); |
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ResetSignal(signal); |
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} |
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} |
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void AsynchronousSignalHandler::OnFileCanReadWithoutBlocking() { |
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struct signalfd_siginfo info; |
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while (base::ReadFromFD(descriptor_, |
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reinterpret_cast<char*>(&info), sizeof(info))) { |
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int signal = info.ssi_signo; |
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Callbacks::iterator callback_it = registered_callbacks_.find(signal); |
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if (callback_it == registered_callbacks_.end()) { |
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LOG(WARNING) << "Unable to find a signal handler for signal: " << signal; |
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// Can happen if a signal has been called multiple time, and the callback |
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// asked to be unregistered the first time. |
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continue; |
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} |
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const SignalHandler& callback = callback_it->second; |
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bool must_unregister = callback.Run(info); |
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if (must_unregister) { |
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UnregisterHandler(signal); |
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} |
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} |
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} |
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void AsynchronousSignalHandler::ResetSignal(int signal) { |
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CHECK_EQ(0, sigdelset(&signal_mask_, signal)); |
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UpdateSignals(); |
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} |
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void AsynchronousSignalHandler::UpdateSignals() { |
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if (descriptor_ != kInvalidDescriptor) { |
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CHECK_EQ(0, sigprocmask(SIG_SETMASK, &saved_signal_mask_, nullptr)); |
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CHECK_EQ(0, sigprocmask(SIG_BLOCK, &signal_mask_, nullptr)); |
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CHECK_EQ(descriptor_, |
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signalfd(descriptor_, &signal_mask_, SFD_CLOEXEC | SFD_NONBLOCK)); |
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} |
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} |
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} // namespace brillo
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