| // |
| // dev_poll_reactor.hpp |
| // ~~~~~~~~~~~~~~~~~~~~ |
| // |
| // Copyright (c) 2003-2008 Christopher M. Kohlhoff (chris at kohlhoff dot com) |
| // |
| // Distributed under the Boost Software License, Version 1.0. (See accompanying |
| // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) |
| // |
| |
| #ifndef BOOST_ASIO_DETAIL_DEV_POLL_REACTOR_HPP |
| #define BOOST_ASIO_DETAIL_DEV_POLL_REACTOR_HPP |
| |
| #if defined(_MSC_VER) && (_MSC_VER >= 1200) |
| # pragma once |
| #endif // defined(_MSC_VER) && (_MSC_VER >= 1200) |
| |
| #include <boost/asio/detail/push_options.hpp> |
| |
| #include <boost/asio/detail/dev_poll_reactor_fwd.hpp> |
| |
| #if defined(BOOST_ASIO_HAS_DEV_POLL) |
| |
| #include <boost/asio/detail/push_options.hpp> |
| #include <cstddef> |
| #include <vector> |
| #include <boost/config.hpp> |
| #include <boost/date_time/posix_time/posix_time_types.hpp> |
| #include <boost/throw_exception.hpp> |
| #include <sys/devpoll.h> |
| #include <boost/system/system_error.hpp> |
| #include <boost/asio/detail/pop_options.hpp> |
| |
| #include <boost/asio/error.hpp> |
| #include <boost/asio/io_service.hpp> |
| #include <boost/asio/detail/bind_handler.hpp> |
| #include <boost/asio/detail/hash_map.hpp> |
| #include <boost/asio/detail/mutex.hpp> |
| #include <boost/asio/detail/task_io_service.hpp> |
| #include <boost/asio/detail/thread.hpp> |
| #include <boost/asio/detail/reactor_op_queue.hpp> |
| #include <boost/asio/detail/select_interrupter.hpp> |
| #include <boost/asio/detail/service_base.hpp> |
| #include <boost/asio/detail/signal_blocker.hpp> |
| #include <boost/asio/detail/socket_types.hpp> |
| #include <boost/asio/detail/timer_queue.hpp> |
| |
| namespace boost { |
| namespace asio { |
| namespace detail { |
| |
| template <bool Own_Thread> |
| class dev_poll_reactor |
| : public boost::asio::detail::service_base<dev_poll_reactor<Own_Thread> > |
| { |
| public: |
| // Per-descriptor data. |
| struct per_descriptor_data |
| { |
| }; |
| |
| // Constructor. |
| dev_poll_reactor(boost::asio::io_service& io_service) |
| : boost::asio::detail::service_base< |
| dev_poll_reactor<Own_Thread> >(io_service), |
| mutex_(), |
| dev_poll_fd_(do_dev_poll_create()), |
| wait_in_progress_(false), |
| interrupter_(), |
| read_op_queue_(), |
| write_op_queue_(), |
| except_op_queue_(), |
| pending_cancellations_(), |
| stop_thread_(false), |
| thread_(0), |
| shutdown_(false) |
| { |
| // Start the reactor's internal thread only if needed. |
| if (Own_Thread) |
| { |
| boost::asio::detail::signal_blocker sb; |
| thread_ = new boost::asio::detail::thread( |
| bind_handler(&dev_poll_reactor::call_run_thread, this)); |
| } |
| |
| // Add the interrupter's descriptor to /dev/poll. |
| ::pollfd ev = { 0 }; |
| ev.fd = interrupter_.read_descriptor(); |
| ev.events = POLLIN | POLLERR; |
| ev.revents = 0; |
| ::write(dev_poll_fd_, &ev, sizeof(ev)); |
| } |
| |
| // Destructor. |
| ~dev_poll_reactor() |
| { |
| shutdown_service(); |
| ::close(dev_poll_fd_); |
| } |
| |
| // Destroy all user-defined handler objects owned by the service. |
| void shutdown_service() |
| { |
| boost::asio::detail::mutex::scoped_lock lock(mutex_); |
| shutdown_ = true; |
| stop_thread_ = true; |
| lock.unlock(); |
| |
| if (thread_) |
| { |
| interrupter_.interrupt(); |
| thread_->join(); |
| delete thread_; |
| thread_ = 0; |
| } |
| |
| read_op_queue_.destroy_operations(); |
| write_op_queue_.destroy_operations(); |
| except_op_queue_.destroy_operations(); |
| |
| for (std::size_t i = 0; i < timer_queues_.size(); ++i) |
| timer_queues_[i]->destroy_timers(); |
| timer_queues_.clear(); |
| } |
| |
| // Initialise the task, but only if the reactor is not in its own thread. |
| void init_task() |
| { |
| if (!Own_Thread) |
| { |
| typedef task_io_service<dev_poll_reactor<Own_Thread> > |
| task_io_service_type; |
| use_service<task_io_service_type>(this->get_io_service()).init_task(); |
| } |
| } |
| |
| // Register a socket with the reactor. Returns 0 on success, system error |
| // code on failure. |
| int register_descriptor(socket_type, per_descriptor_data&) |
| { |
| return 0; |
| } |
| |
| // Start a new read operation. The handler object will be invoked when the |
| // given descriptor is ready to be read, or an error has occurred. |
| template <typename Handler> |
| void start_read_op(socket_type descriptor, per_descriptor_data&, |
| Handler handler, bool allow_speculative_read = true) |
| { |
| boost::asio::detail::mutex::scoped_lock lock(mutex_); |
| |
| if (shutdown_) |
| return; |
| |
| if (allow_speculative_read) |
| { |
| if (!read_op_queue_.has_operation(descriptor)) |
| { |
| boost::system::error_code ec; |
| std::size_t bytes_transferred = 0; |
| if (handler.perform(ec, bytes_transferred)) |
| { |
| handler.complete(ec, bytes_transferred); |
| return; |
| } |
| } |
| } |
| |
| if (read_op_queue_.enqueue_operation(descriptor, handler)) |
| { |
| ::pollfd& ev = add_pending_event_change(descriptor); |
| ev.events = POLLIN | POLLERR | POLLHUP; |
| if (write_op_queue_.has_operation(descriptor)) |
| ev.events |= POLLOUT; |
| if (except_op_queue_.has_operation(descriptor)) |
| ev.events |= POLLPRI; |
| interrupter_.interrupt(); |
| } |
| } |
| |
| // Start a new write operation. The handler object will be invoked when the |
| // given descriptor is ready to be written, or an error has occurred. |
| template <typename Handler> |
| void start_write_op(socket_type descriptor, per_descriptor_data&, |
| Handler handler, bool allow_speculative_write = true) |
| { |
| boost::asio::detail::mutex::scoped_lock lock(mutex_); |
| |
| if (shutdown_) |
| return; |
| |
| if (allow_speculative_write) |
| { |
| if (!write_op_queue_.has_operation(descriptor)) |
| { |
| boost::system::error_code ec; |
| std::size_t bytes_transferred = 0; |
| if (handler.perform(ec, bytes_transferred)) |
| { |
| handler.complete(ec, bytes_transferred); |
| return; |
| } |
| } |
| } |
| |
| if (write_op_queue_.enqueue_operation(descriptor, handler)) |
| { |
| ::pollfd& ev = add_pending_event_change(descriptor); |
| ev.events = POLLOUT | POLLERR | POLLHUP; |
| if (read_op_queue_.has_operation(descriptor)) |
| ev.events |= POLLIN; |
| if (except_op_queue_.has_operation(descriptor)) |
| ev.events |= POLLPRI; |
| interrupter_.interrupt(); |
| } |
| } |
| |
| // Start a new exception operation. The handler object will be invoked when |
| // the given descriptor has exception information, or an error has occurred. |
| template <typename Handler> |
| void start_except_op(socket_type descriptor, |
| per_descriptor_data&, Handler handler) |
| { |
| boost::asio::detail::mutex::scoped_lock lock(mutex_); |
| |
| if (shutdown_) |
| return; |
| |
| if (except_op_queue_.enqueue_operation(descriptor, handler)) |
| { |
| ::pollfd& ev = add_pending_event_change(descriptor); |
| ev.events = POLLPRI | POLLERR | POLLHUP; |
| if (read_op_queue_.has_operation(descriptor)) |
| ev.events |= POLLIN; |
| if (write_op_queue_.has_operation(descriptor)) |
| ev.events |= POLLOUT; |
| interrupter_.interrupt(); |
| } |
| } |
| |
| // Start a new write operation. The handler object will be invoked when the |
| // information available, or an error has occurred. |
| template <typename Handler> |
| void start_connect_op(socket_type descriptor, |
| per_descriptor_data&, Handler handler) |
| { |
| boost::asio::detail::mutex::scoped_lock lock(mutex_); |
| |
| if (shutdown_) |
| return; |
| |
| if (write_op_queue_.enqueue_operation(descriptor, handler)) |
| { |
| ::pollfd& ev = add_pending_event_change(descriptor); |
| ev.events = POLLOUT | POLLERR | POLLHUP; |
| if (read_op_queue_.has_operation(descriptor)) |
| ev.events |= POLLIN; |
| if (except_op_queue_.has_operation(descriptor)) |
| ev.events |= POLLPRI; |
| interrupter_.interrupt(); |
| } |
| } |
| |
| // Cancel all operations associated with the given descriptor. The |
| // handlers associated with the descriptor will be invoked with the |
| // operation_aborted error. |
| void cancel_ops(socket_type descriptor, per_descriptor_data&) |
| { |
| boost::asio::detail::mutex::scoped_lock lock(mutex_); |
| cancel_ops_unlocked(descriptor); |
| } |
| |
| // Cancel any operations that are running against the descriptor and remove |
| // its registration from the reactor. |
| void close_descriptor(socket_type descriptor, per_descriptor_data&) |
| { |
| boost::asio::detail::mutex::scoped_lock lock(mutex_); |
| |
| // Remove the descriptor from /dev/poll. |
| ::pollfd& ev = add_pending_event_change(descriptor); |
| ev.events = POLLREMOVE; |
| interrupter_.interrupt(); |
| |
| // Cancel any outstanding operations associated with the descriptor. |
| cancel_ops_unlocked(descriptor); |
| } |
| |
| // Add a new timer queue to the reactor. |
| template <typename Time_Traits> |
| void add_timer_queue(timer_queue<Time_Traits>& timer_queue) |
| { |
| boost::asio::detail::mutex::scoped_lock lock(mutex_); |
| timer_queues_.push_back(&timer_queue); |
| } |
| |
| // Remove a timer queue from the reactor. |
| template <typename Time_Traits> |
| void remove_timer_queue(timer_queue<Time_Traits>& timer_queue) |
| { |
| boost::asio::detail::mutex::scoped_lock lock(mutex_); |
| for (std::size_t i = 0; i < timer_queues_.size(); ++i) |
| { |
| if (timer_queues_[i] == &timer_queue) |
| { |
| timer_queues_.erase(timer_queues_.begin() + i); |
| return; |
| } |
| } |
| } |
| |
| // Schedule a timer in the given timer queue to expire at the specified |
| // absolute time. The handler object will be invoked when the timer expires. |
| template <typename Time_Traits, typename Handler> |
| void schedule_timer(timer_queue<Time_Traits>& timer_queue, |
| const typename Time_Traits::time_type& time, Handler handler, void* token) |
| { |
| boost::asio::detail::mutex::scoped_lock lock(mutex_); |
| if (!shutdown_) |
| if (timer_queue.enqueue_timer(time, handler, token)) |
| interrupter_.interrupt(); |
| } |
| |
| // Cancel the timer associated with the given token. Returns the number of |
| // handlers that have been posted or dispatched. |
| template <typename Time_Traits> |
| std::size_t cancel_timer(timer_queue<Time_Traits>& timer_queue, void* token) |
| { |
| boost::asio::detail::mutex::scoped_lock lock(mutex_); |
| std::size_t n = timer_queue.cancel_timer(token); |
| if (n > 0) |
| interrupter_.interrupt(); |
| return n; |
| } |
| |
| private: |
| friend class task_io_service<dev_poll_reactor<Own_Thread> >; |
| |
| // Run /dev/poll once until interrupted or events are ready to be dispatched. |
| void run(bool block) |
| { |
| boost::asio::detail::mutex::scoped_lock lock(mutex_); |
| |
| // Dispatch any operation cancellations that were made while the select |
| // loop was not running. |
| read_op_queue_.perform_cancellations(); |
| write_op_queue_.perform_cancellations(); |
| except_op_queue_.perform_cancellations(); |
| for (std::size_t i = 0; i < timer_queues_.size(); ++i) |
| timer_queues_[i]->dispatch_cancellations(); |
| |
| // Check if the thread is supposed to stop. |
| if (stop_thread_) |
| { |
| complete_operations_and_timers(lock); |
| return; |
| } |
| |
| // We can return immediately if there's no work to do and the reactor is |
| // not supposed to block. |
| if (!block && read_op_queue_.empty() && write_op_queue_.empty() |
| && except_op_queue_.empty() && all_timer_queues_are_empty()) |
| { |
| complete_operations_and_timers(lock); |
| return; |
| } |
| |
| // Write the pending event registration changes to the /dev/poll descriptor. |
| std::size_t events_size = sizeof(::pollfd) * pending_event_changes_.size(); |
| if (events_size > 0) |
| { |
| errno = 0; |
| int result = ::write(dev_poll_fd_, |
| &pending_event_changes_[0], events_size); |
| if (result != static_cast<int>(events_size)) |
| { |
| for (std::size_t i = 0; i < pending_event_changes_.size(); ++i) |
| { |
| int descriptor = pending_event_changes_[i].fd; |
| boost::system::error_code ec = boost::system::error_code( |
| errno, boost::asio::error::get_system_category()); |
| read_op_queue_.perform_all_operations(descriptor, ec); |
| write_op_queue_.perform_all_operations(descriptor, ec); |
| except_op_queue_.perform_all_operations(descriptor, ec); |
| } |
| } |
| pending_event_changes_.clear(); |
| pending_event_change_index_.clear(); |
| } |
| |
| int timeout = block ? get_timeout() : 0; |
| wait_in_progress_ = true; |
| lock.unlock(); |
| |
| // Block on the /dev/poll descriptor. |
| ::pollfd events[128] = { { 0 } }; |
| ::dvpoll dp = { 0 }; |
| dp.dp_fds = events; |
| dp.dp_nfds = 128; |
| dp.dp_timeout = timeout; |
| int num_events = ::ioctl(dev_poll_fd_, DP_POLL, &dp); |
| |
| lock.lock(); |
| wait_in_progress_ = false; |
| |
| // Block signals while performing operations. |
| boost::asio::detail::signal_blocker sb; |
| |
| // Dispatch the waiting events. |
| for (int i = 0; i < num_events; ++i) |
| { |
| int descriptor = events[i].fd; |
| if (descriptor == interrupter_.read_descriptor()) |
| { |
| interrupter_.reset(); |
| } |
| else |
| { |
| bool more_reads = false; |
| bool more_writes = false; |
| bool more_except = false; |
| boost::system::error_code ec; |
| |
| // Exception operations must be processed first to ensure that any |
| // out-of-band data is read before normal data. |
| if (events[i].events & (POLLPRI | POLLERR | POLLHUP)) |
| more_except = except_op_queue_.perform_operation(descriptor, ec); |
| else |
| more_except = except_op_queue_.has_operation(descriptor); |
| |
| if (events[i].events & (POLLIN | POLLERR | POLLHUP)) |
| more_reads = read_op_queue_.perform_operation(descriptor, ec); |
| else |
| more_reads = read_op_queue_.has_operation(descriptor); |
| |
| if (events[i].events & (POLLOUT | POLLERR | POLLHUP)) |
| more_writes = write_op_queue_.perform_operation(descriptor, ec); |
| else |
| more_writes = write_op_queue_.has_operation(descriptor); |
| |
| if ((events[i].events & (POLLERR | POLLHUP)) != 0 |
| && (events[i].events & ~(POLLERR | POLLHUP)) == 0 |
| && !more_except && !more_reads && !more_writes) |
| { |
| // If we have an event and no operations associated with the |
| // descriptor then we need to delete the descriptor from /dev/poll. |
| // The poll operation can produce POLLHUP or POLLERR events when there |
| // is no operation pending, so if we do not remove the descriptor we |
| // can end up in a tight polling loop. |
| ::pollfd ev = { 0 }; |
| ev.fd = descriptor; |
| ev.events = POLLREMOVE; |
| ev.revents = 0; |
| ::write(dev_poll_fd_, &ev, sizeof(ev)); |
| } |
| else |
| { |
| ::pollfd ev = { 0 }; |
| ev.fd = descriptor; |
| ev.events = POLLERR | POLLHUP; |
| if (more_reads) |
| ev.events |= POLLIN; |
| if (more_writes) |
| ev.events |= POLLOUT; |
| if (more_except) |
| ev.events |= POLLPRI; |
| ev.revents = 0; |
| int result = ::write(dev_poll_fd_, &ev, sizeof(ev)); |
| if (result != sizeof(ev)) |
| { |
| ec = boost::system::error_code(errno, |
| boost::asio::error::get_system_category()); |
| read_op_queue_.perform_all_operations(descriptor, ec); |
| write_op_queue_.perform_all_operations(descriptor, ec); |
| except_op_queue_.perform_all_operations(descriptor, ec); |
| } |
| } |
| } |
| } |
| read_op_queue_.perform_cancellations(); |
| write_op_queue_.perform_cancellations(); |
| except_op_queue_.perform_cancellations(); |
| for (std::size_t i = 0; i < timer_queues_.size(); ++i) |
| { |
| timer_queues_[i]->dispatch_timers(); |
| timer_queues_[i]->dispatch_cancellations(); |
| } |
| |
| // Issue any pending cancellations. |
| for (size_t i = 0; i < pending_cancellations_.size(); ++i) |
| cancel_ops_unlocked(pending_cancellations_[i]); |
| pending_cancellations_.clear(); |
| |
| complete_operations_and_timers(lock); |
| } |
| |
| // Run the select loop in the thread. |
| void run_thread() |
| { |
| boost::asio::detail::mutex::scoped_lock lock(mutex_); |
| while (!stop_thread_) |
| { |
| lock.unlock(); |
| run(true); |
| lock.lock(); |
| } |
| } |
| |
| // Entry point for the select loop thread. |
| static void call_run_thread(dev_poll_reactor* reactor) |
| { |
| reactor->run_thread(); |
| } |
| |
| // Interrupt the select loop. |
| void interrupt() |
| { |
| interrupter_.interrupt(); |
| } |
| |
| // Create the /dev/poll file descriptor. Throws an exception if the descriptor |
| // cannot be created. |
| static int do_dev_poll_create() |
| { |
| int fd = ::open("/dev/poll", O_RDWR); |
| if (fd == -1) |
| { |
| boost::throw_exception( |
| boost::system::system_error( |
| boost::system::error_code(errno, |
| boost::asio::error::get_system_category()), |
| "/dev/poll")); |
| } |
| return fd; |
| } |
| |
| // Check if all timer queues are empty. |
| bool all_timer_queues_are_empty() const |
| { |
| for (std::size_t i = 0; i < timer_queues_.size(); ++i) |
| if (!timer_queues_[i]->empty()) |
| return false; |
| return true; |
| } |
| |
| // Get the timeout value for the /dev/poll DP_POLL operation. The timeout |
| // value is returned as a number of milliseconds. A return value of -1 |
| // indicates that the poll should block indefinitely. |
| int get_timeout() |
| { |
| if (all_timer_queues_are_empty()) |
| return -1; |
| |
| // By default we will wait no longer than 5 minutes. This will ensure that |
| // any changes to the system clock are detected after no longer than this. |
| boost::posix_time::time_duration minimum_wait_duration |
| = boost::posix_time::minutes(5); |
| |
| for (std::size_t i = 0; i < timer_queues_.size(); ++i) |
| { |
| boost::posix_time::time_duration wait_duration |
| = timer_queues_[i]->wait_duration(); |
| if (wait_duration < minimum_wait_duration) |
| minimum_wait_duration = wait_duration; |
| } |
| |
| if (minimum_wait_duration > boost::posix_time::time_duration()) |
| { |
| int milliseconds = minimum_wait_duration.total_milliseconds(); |
| return milliseconds > 0 ? milliseconds : 1; |
| } |
| else |
| { |
| return 0; |
| } |
| } |
| |
| // Cancel all operations associated with the given descriptor. The do_cancel |
| // function of the handler objects will be invoked. This function does not |
| // acquire the dev_poll_reactor's mutex. |
| void cancel_ops_unlocked(socket_type descriptor) |
| { |
| bool interrupt = read_op_queue_.cancel_operations(descriptor); |
| interrupt = write_op_queue_.cancel_operations(descriptor) || interrupt; |
| interrupt = except_op_queue_.cancel_operations(descriptor) || interrupt; |
| if (interrupt) |
| interrupter_.interrupt(); |
| } |
| |
| // Clean up operations and timers. We must not hold the lock since the |
| // destructors may make calls back into this reactor. We make a copy of the |
| // vector of timer queues since the original may be modified while the lock |
| // is not held. |
| void complete_operations_and_timers( |
| boost::asio::detail::mutex::scoped_lock& lock) |
| { |
| timer_queues_for_cleanup_ = timer_queues_; |
| lock.unlock(); |
| read_op_queue_.complete_operations(); |
| write_op_queue_.complete_operations(); |
| except_op_queue_.complete_operations(); |
| for (std::size_t i = 0; i < timer_queues_for_cleanup_.size(); ++i) |
| timer_queues_for_cleanup_[i]->complete_timers(); |
| } |
| |
| // Add a pending event entry for the given descriptor. |
| ::pollfd& add_pending_event_change(int descriptor) |
| { |
| hash_map<int, std::size_t>::iterator iter |
| = pending_event_change_index_.find(descriptor); |
| if (iter == pending_event_change_index_.end()) |
| { |
| std::size_t index = pending_event_changes_.size(); |
| pending_event_changes_.reserve(pending_event_changes_.size() + 1); |
| pending_event_change_index_.insert(std::make_pair(descriptor, index)); |
| pending_event_changes_.push_back(::pollfd()); |
| pending_event_changes_[index].fd = descriptor; |
| pending_event_changes_[index].revents = 0; |
| return pending_event_changes_[index]; |
| } |
| else |
| { |
| return pending_event_changes_[iter->second]; |
| } |
| } |
| |
| // Mutex to protect access to internal data. |
| boost::asio::detail::mutex mutex_; |
| |
| // The /dev/poll file descriptor. |
| int dev_poll_fd_; |
| |
| // Vector of /dev/poll events waiting to be written to the descriptor. |
| std::vector< ::pollfd> pending_event_changes_; |
| |
| // Hash map to associate a descriptor with a pending event change index. |
| hash_map<int, std::size_t> pending_event_change_index_; |
| |
| // Whether the DP_POLL operation is currently in progress |
| bool wait_in_progress_; |
| |
| // The interrupter is used to break a blocking DP_POLL operation. |
| select_interrupter interrupter_; |
| |
| // The queue of read operations. |
| reactor_op_queue<socket_type> read_op_queue_; |
| |
| // The queue of write operations. |
| reactor_op_queue<socket_type> write_op_queue_; |
| |
| // The queue of except operations. |
| reactor_op_queue<socket_type> except_op_queue_; |
| |
| // The timer queues. |
| std::vector<timer_queue_base*> timer_queues_; |
| |
| // A copy of the timer queues, used when cleaning up timers. The copy is |
| // stored as a class data member to avoid unnecessary memory allocation. |
| std::vector<timer_queue_base*> timer_queues_for_cleanup_; |
| |
| // The descriptors that are pending cancellation. |
| std::vector<socket_type> pending_cancellations_; |
| |
| // Does the reactor loop thread need to stop. |
| bool stop_thread_; |
| |
| // The thread that is running the reactor loop. |
| boost::asio::detail::thread* thread_; |
| |
| // Whether the service has been shut down. |
| bool shutdown_; |
| }; |
| |
| } // namespace detail |
| } // namespace asio |
| } // namespace boost |
| |
| #endif // defined(BOOST_ASIO_HAS_DEV_POLL) |
| |
| #include <boost/asio/detail/pop_options.hpp> |
| |
| #endif // BOOST_ASIO_DETAIL_DEV_POLL_REACTOR_HPP |