// // detail/epoll_reactor.hpp // ~~~~~~~~~~~~~~~~~~~~~~~~ // // Copyright (c) 2003-2021 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 ASIO_DETAIL_EPOLL_REACTOR_HPP #define ASIO_DETAIL_EPOLL_REACTOR_HPP #if defined(_MSC_VER) && (_MSC_VER >= 1200) # pragma once #endif // defined(_MSC_VER) && (_MSC_VER >= 1200) #include "asio/detail/config.hpp" #if defined(ASIO_HAS_EPOLL) #include "asio/detail/atomic_count.hpp" #include "asio/detail/conditionally_enabled_mutex.hpp" #include "asio/detail/limits.hpp" #include "asio/detail/object_pool.hpp" #include "asio/detail/op_queue.hpp" #include "asio/detail/reactor_op.hpp" #include "asio/detail/select_interrupter.hpp" #include "asio/detail/socket_types.hpp" #include "asio/detail/timer_queue_base.hpp" #include "asio/detail/timer_queue_set.hpp" #include "asio/detail/wait_op.hpp" #include "asio/execution_context.hpp" #if defined(ASIO_HAS_TIMERFD) # include #endif // defined(ASIO_HAS_TIMERFD) #include "asio/detail/push_options.hpp" namespace asio { namespace detail { class epoll_reactor : public execution_context_service_base { private: // The mutex type used by this reactor. typedef conditionally_enabled_mutex mutex; public: enum op_types { read_op = 0, write_op = 1, connect_op = 1, except_op = 2, max_ops = 3 }; // Per-descriptor queues. class descriptor_state : operation { friend class epoll_reactor; friend class object_pool_access; descriptor_state* next_; descriptor_state* prev_; mutex mutex_; epoll_reactor* reactor_; int descriptor_; uint32_t registered_events_; op_queue op_queue_[max_ops]; bool try_speculative_[max_ops]; bool shutdown_; ASIO_DECL descriptor_state(bool locking); void set_ready_events(uint32_t events) { task_result_ = events; } void add_ready_events(uint32_t events) { task_result_ |= events; } ASIO_DECL operation* perform_io(uint32_t events); ASIO_DECL static void do_complete( void* owner, operation* base, const asio::error_code& ec, std::size_t bytes_transferred); }; // Per-descriptor data. typedef descriptor_state* per_descriptor_data; // Constructor. ASIO_DECL epoll_reactor(asio::execution_context& ctx); // Destructor. ASIO_DECL ~epoll_reactor(); // Destroy all user-defined handler objects owned by the service. ASIO_DECL void shutdown(); // Recreate internal descriptors following a fork. ASIO_DECL void notify_fork( asio::execution_context::fork_event fork_ev); // Initialise the task. ASIO_DECL void init_task(); // Register a socket with the reactor. Returns 0 on success, system error // code on failure. ASIO_DECL int register_descriptor(socket_type descriptor, per_descriptor_data& descriptor_data); // Register a descriptor with an associated single operation. Returns 0 on // success, system error code on failure. ASIO_DECL int register_internal_descriptor( int op_type, socket_type descriptor, per_descriptor_data& descriptor_data, reactor_op* op); // Move descriptor registration from one descriptor_data object to another. ASIO_DECL void move_descriptor(socket_type descriptor, per_descriptor_data& target_descriptor_data, per_descriptor_data& source_descriptor_data); // Post a reactor operation for immediate completion. void post_immediate_completion(reactor_op* op, bool is_continuation) { scheduler_.post_immediate_completion(op, is_continuation); } // Start a new operation. The reactor operation will be performed when the // given descriptor is flagged as ready, or an error has occurred. ASIO_DECL void start_op(int op_type, socket_type descriptor, per_descriptor_data& descriptor_data, reactor_op* op, bool is_continuation, bool allow_speculative); // Cancel all operations associated with the given descriptor. The // handlers associated with the descriptor will be invoked with the // operation_aborted error. ASIO_DECL void cancel_ops(socket_type descriptor, per_descriptor_data& descriptor_data); // Cancel any operations that are running against the descriptor and remove // its registration from the reactor. The reactor resources associated with // the descriptor must be released by calling cleanup_descriptor_data. ASIO_DECL void deregister_descriptor(socket_type descriptor, per_descriptor_data& descriptor_data, bool closing); // Remove the descriptor's registration from the reactor. The reactor // resources associated with the descriptor must be released by calling // cleanup_descriptor_data. ASIO_DECL void deregister_internal_descriptor( socket_type descriptor, per_descriptor_data& descriptor_data); // Perform any post-deregistration cleanup tasks associated with the // descriptor data. ASIO_DECL void cleanup_descriptor_data( per_descriptor_data& descriptor_data); // Add a new timer queue to the reactor. template void add_timer_queue(timer_queue& timer_queue); // Remove a timer queue from the reactor. template void remove_timer_queue(timer_queue& timer_queue); // Schedule a new operation in the given timer queue to expire at the // specified absolute time. template void schedule_timer(timer_queue& queue, const typename Time_Traits::time_type& time, typename timer_queue::per_timer_data& timer, wait_op* op); // Cancel the timer operations associated with the given token. Returns the // number of operations that have been posted or dispatched. template std::size_t cancel_timer(timer_queue& queue, typename timer_queue::per_timer_data& timer, std::size_t max_cancelled = (std::numeric_limits::max)()); // Move the timer operations associated with the given timer. template void move_timer(timer_queue& queue, typename timer_queue::per_timer_data& target, typename timer_queue::per_timer_data& source); // Run epoll once until interrupted or events are ready to be dispatched. ASIO_DECL void run(long usec, op_queue& ops); // Interrupt the select loop. ASIO_DECL void interrupt(); private: // The hint to pass to epoll_create to size its data structures. enum { epoll_size = 20000 }; // Create the epoll file descriptor. Throws an exception if the descriptor // cannot be created. ASIO_DECL static int do_epoll_create(); // Create the timerfd file descriptor. Does not throw. ASIO_DECL static int do_timerfd_create(); // Allocate a new descriptor state object. ASIO_DECL descriptor_state* allocate_descriptor_state(); // Free an existing descriptor state object. ASIO_DECL void free_descriptor_state(descriptor_state* s); // Helper function to add a new timer queue. ASIO_DECL void do_add_timer_queue(timer_queue_base& queue); // Helper function to remove a timer queue. ASIO_DECL void do_remove_timer_queue(timer_queue_base& queue); // Called to recalculate and update the timeout. ASIO_DECL void update_timeout(); // Get the timeout value for the epoll_wait call. The timeout value is // returned as a number of milliseconds. A return value of -1 indicates // that epoll_wait should block indefinitely. ASIO_DECL int get_timeout(int msec); #if defined(ASIO_HAS_TIMERFD) // Get the timeout value for the timer descriptor. The return value is the // flag argument to be used when calling timerfd_settime. ASIO_DECL int get_timeout(itimerspec& ts); #endif // defined(ASIO_HAS_TIMERFD) // The scheduler implementation used to post completions. scheduler& scheduler_; // Mutex to protect access to internal data. mutex mutex_; // The interrupter is used to break a blocking epoll_wait call. select_interrupter interrupter_; // The epoll file descriptor. int epoll_fd_; // The timer file descriptor. int timer_fd_; // The timer queues. timer_queue_set timer_queues_; // Whether the service has been shut down. bool shutdown_; // Mutex to protect access to the registered descriptors. mutex registered_descriptors_mutex_; // Keep track of all registered descriptors. object_pool registered_descriptors_; // Helper class to do post-perform_io cleanup. struct perform_io_cleanup_on_block_exit; friend struct perform_io_cleanup_on_block_exit; }; } // namespace detail } // namespace asio #include "asio/detail/pop_options.hpp" #include "asio/detail/impl/epoll_reactor.hpp" #if defined(ASIO_HEADER_ONLY) # include "asio/detail/impl/epoll_reactor.ipp" #endif // defined(ASIO_HEADER_ONLY) #endif // defined(ASIO_HAS_EPOLL) #endif // ASIO_DETAIL_EPOLL_REACTOR_HPP