Benjamin Lerman | 21c7e37 | 2014-07-10 14:20:27 +0200 | [diff] [blame] | 1 | // Copyright 2014 The Chromium OS Authors. All rights reserved. |
| 2 | // Use of this source code is governed by a BSD-style license that can be |
| 3 | // found in the LICENSE file. |
| 4 | |
| 5 | #include "chromeos/asynchronous_signal_handler.h" |
| 6 | |
| 7 | #include <signal.h> |
| 8 | #include <sys/types.h> |
| 9 | #include <unistd.h> |
| 10 | |
Ben Chan | cb10464 | 2014-09-05 08:21:06 -0700 | [diff] [blame^] | 11 | #include <base/files/file_util.h> |
Benjamin Lerman | 21c7e37 | 2014-07-10 14:20:27 +0200 | [diff] [blame] | 12 | #include <base/logging.h> |
| 13 | #include <base/message_loop/message_loop.h> |
| 14 | |
Benjamin Lerman | 21c7e37 | 2014-07-10 14:20:27 +0200 | [diff] [blame] | 15 | namespace { |
| 16 | const int kInvalidDescriptor = -1; |
| 17 | } // namespace |
| 18 | |
| 19 | namespace chromeos { |
| 20 | |
| 21 | AsynchronousSignalHandler::AsynchronousSignalHandler() |
| 22 | : fd_watcher_(new base::MessageLoopForIO::FileDescriptorWatcher), |
| 23 | descriptor_(kInvalidDescriptor) { |
| 24 | CHECK_EQ(sigemptyset(&signal_mask_), 0) << "Failed to initialize signal mask"; |
| 25 | CHECK_EQ(sigemptyset(&saved_signal_mask_), 0) |
| 26 | << "Failed to initialize signal mask"; |
| 27 | } |
| 28 | |
| 29 | AsynchronousSignalHandler::~AsynchronousSignalHandler() { |
| 30 | if (descriptor_ != kInvalidDescriptor) { |
| 31 | fd_watcher_->StopWatchingFileDescriptor(); |
| 32 | |
| 33 | if (close(descriptor_) != 0) |
| 34 | PLOG(WARNING) << "Failed to close file descriptor"; |
| 35 | |
| 36 | descriptor_ = kInvalidDescriptor; |
Alex Vakulenko | 9d99bc6 | 2014-08-28 13:42:01 -0700 | [diff] [blame] | 37 | CHECK_EQ(0, sigprocmask(SIG_SETMASK, &saved_signal_mask_, nullptr)); |
Benjamin Lerman | 21c7e37 | 2014-07-10 14:20:27 +0200 | [diff] [blame] | 38 | } |
| 39 | } |
| 40 | |
| 41 | void AsynchronousSignalHandler::Init() { |
| 42 | CHECK_EQ(kInvalidDescriptor, descriptor_); |
| 43 | CHECK_EQ(0, sigprocmask(SIG_BLOCK, &signal_mask_, &saved_signal_mask_)); |
| 44 | descriptor_ = |
| 45 | signalfd(descriptor_, &signal_mask_, SFD_CLOEXEC | SFD_NONBLOCK); |
| 46 | CHECK_NE(kInvalidDescriptor, descriptor_); |
| 47 | CHECK(base::MessageLoopForIO::current()->WatchFileDescriptor( |
| 48 | descriptor_, true, base::MessageLoopForIO::WATCH_READ, fd_watcher_.get(), |
| 49 | this)) |
| 50 | << "Watching shutdown pipe failed."; |
| 51 | } |
| 52 | |
| 53 | void AsynchronousSignalHandler::RegisterHandler(int signal, |
| 54 | const SignalHandler& callback) { |
| 55 | registered_callbacks_[signal] = callback; |
| 56 | CHECK_EQ(0, sigaddset(&signal_mask_, signal)); |
| 57 | UpdateSignals(); |
| 58 | } |
| 59 | |
| 60 | void AsynchronousSignalHandler::UnregisterHandler(int signal) { |
| 61 | Callbacks::iterator callback_it = registered_callbacks_.find(signal); |
| 62 | if (callback_it != registered_callbacks_.end()) { |
| 63 | registered_callbacks_.erase(callback_it); |
| 64 | ResetSignal(signal); |
| 65 | } |
| 66 | } |
| 67 | |
| 68 | void AsynchronousSignalHandler::OnFileCanReadWithoutBlocking(int fd) { |
| 69 | struct signalfd_siginfo info; |
| 70 | while (base::ReadFromFD(fd, reinterpret_cast<char*>(&info), sizeof(info))) { |
| 71 | int signal = info.ssi_signo; |
| 72 | Callbacks::iterator callback_it = registered_callbacks_.find(signal); |
| 73 | if (callback_it == registered_callbacks_.end()) { |
| 74 | LOG(WARNING) << "Unable to find a signal handler for signal: " << signal; |
| 75 | // Can happen if a signal has been called multiple time, and the callback |
| 76 | // asked to be unregistered the first time. |
| 77 | continue; |
| 78 | } |
| 79 | const SignalHandler& callback = callback_it->second; |
| 80 | bool must_unregister = callback.Run(info); |
| 81 | if (must_unregister) { |
| 82 | UnregisterHandler(signal); |
| 83 | } |
| 84 | } |
| 85 | } |
| 86 | |
| 87 | void AsynchronousSignalHandler::OnFileCanWriteWithoutBlocking(int fd) { |
| 88 | NOTREACHED(); |
| 89 | } |
| 90 | |
| 91 | void AsynchronousSignalHandler::ResetSignal(int signal) { |
| 92 | CHECK_EQ(0, sigdelset(&signal_mask_, signal)); |
| 93 | UpdateSignals(); |
| 94 | } |
| 95 | |
| 96 | void AsynchronousSignalHandler::UpdateSignals() { |
| 97 | if (descriptor_ != kInvalidDescriptor) { |
Alex Vakulenko | 9d99bc6 | 2014-08-28 13:42:01 -0700 | [diff] [blame] | 98 | CHECK_EQ(0, sigprocmask(SIG_SETMASK, &saved_signal_mask_, nullptr)); |
| 99 | CHECK_EQ(0, sigprocmask(SIG_BLOCK, &signal_mask_, nullptr)); |
Benjamin Lerman | 21c7e37 | 2014-07-10 14:20:27 +0200 | [diff] [blame] | 100 | CHECK_EQ(descriptor_, |
| 101 | signalfd(descriptor_, &signal_mask_, SFD_CLOEXEC | SFD_NONBLOCK)); |
| 102 | } |
| 103 | } |
| 104 | |
| 105 | } // namespace chromeos |