1//
2// detail/epoll_reactor.hpp
3// ~~~~~~~~~~~~~~~~~~~~~~~~
4//
5// Copyright (c) 2003-2015 Christopher M. Kohlhoff (chris at kohlhoff dot com)
6//
7// Distributed under the Boost Software License, Version 1.0. (See accompanying
8// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
9//
10
11#ifndef BOOST_ASIO_DETAIL_EPOLL_REACTOR_HPP
12#define BOOST_ASIO_DETAIL_EPOLL_REACTOR_HPP
13
14#if defined(_MSC_VER) && (_MSC_VER >= 1200)
15# pragma once
16#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
17
18#include <boost/asio/detail/config.hpp>
19
20#if defined(BOOST_ASIO_HAS_EPOLL)
21
22#include <boost/asio/io_service.hpp>
23#include <boost/asio/detail/atomic_count.hpp>
24#include <boost/asio/detail/limits.hpp>
25#include <boost/asio/detail/mutex.hpp>
26#include <boost/asio/detail/object_pool.hpp>
27#include <boost/asio/detail/op_queue.hpp>
28#include <boost/asio/detail/reactor_op.hpp>
29#include <boost/asio/detail/select_interrupter.hpp>
30#include <boost/asio/detail/socket_types.hpp>
31#include <boost/asio/detail/timer_queue_base.hpp>
32#include <boost/asio/detail/timer_queue_set.hpp>
33#include <boost/asio/detail/wait_op.hpp>
34
35#include <boost/asio/detail/push_options.hpp>
36
37namespace boost {
38namespace asio {
39namespace detail {
40
41class epoll_reactor
42 : public boost::asio::detail::service_base<epoll_reactor>
43{
44public:
45 enum op_types { read_op = 0, write_op = 1,
46 connect_op = 1, except_op = 2, max_ops = 3 };
47
48 // Per-descriptor queues.
49 class descriptor_state : operation
50 {
51 friend class epoll_reactor;
52 friend class object_pool_access;
53
54 descriptor_state* next_;
55 descriptor_state* prev_;
56
57 mutex mutex_;
58 epoll_reactor* reactor_;
59 int descriptor_;
60 uint32_t registered_events_;
61 op_queue<reactor_op> op_queue_[max_ops];
62 bool shutdown_;
63
64 BOOST_ASIO_DECL descriptor_state();
65 void set_ready_events(uint32_t events) { task_result_ = events; }
66 BOOST_ASIO_DECL operation* perform_io(uint32_t events);
67 BOOST_ASIO_DECL static void do_complete(
68 io_service_impl* owner, operation* base,
69 const boost::system::error_code& ec, std::size_t bytes_transferred);
70 };
71
72 // Per-descriptor data.
73 typedef descriptor_state* per_descriptor_data;
74
75 // Constructor.
76 BOOST_ASIO_DECL epoll_reactor(boost::asio::io_service& io_service);
77
78 // Destructor.
79 BOOST_ASIO_DECL ~epoll_reactor();
80
81 // Destroy all user-defined handler objects owned by the service.
82 BOOST_ASIO_DECL void shutdown_service();
83
84 // Recreate internal descriptors following a fork.
85 BOOST_ASIO_DECL void fork_service(
86 boost::asio::io_service::fork_event fork_ev);
87
88 // Initialise the task.
89 BOOST_ASIO_DECL void init_task();
90
91 // Register a socket with the reactor. Returns 0 on success, system error
92 // code on failure.
93 BOOST_ASIO_DECL int register_descriptor(socket_type descriptor,
94 per_descriptor_data& descriptor_data);
95
96 // Register a descriptor with an associated single operation. Returns 0 on
97 // success, system error code on failure.
98 BOOST_ASIO_DECL int register_internal_descriptor(
99 int op_type, socket_type descriptor,
100 per_descriptor_data& descriptor_data, reactor_op* op);
101
102 // Move descriptor registration from one descriptor_data object to another.
103 BOOST_ASIO_DECL void move_descriptor(socket_type descriptor,
104 per_descriptor_data& target_descriptor_data,
105 per_descriptor_data& source_descriptor_data);
106
107 // Post a reactor operation for immediate completion.
108 void post_immediate_completion(reactor_op* op, bool is_continuation)
109 {
110 io_service_.post_immediate_completion(op, is_continuation);
111 }
112
113 // Start a new operation. The reactor operation will be performed when the
114 // given descriptor is flagged as ready, or an error has occurred.
115 BOOST_ASIO_DECL void start_op(int op_type, socket_type descriptor,
116 per_descriptor_data& descriptor_data, reactor_op* op,
117 bool is_continuation, bool allow_speculative);
118
119 // Cancel all operations associated with the given descriptor. The
120 // handlers associated with the descriptor will be invoked with the
121 // operation_aborted error.
122 BOOST_ASIO_DECL void cancel_ops(socket_type descriptor,
123 per_descriptor_data& descriptor_data);
124
125 // Cancel any operations that are running against the descriptor and remove
126 // its registration from the reactor.
127 BOOST_ASIO_DECL void deregister_descriptor(socket_type descriptor,
128 per_descriptor_data& descriptor_data, bool closing);
129
130 // Remote the descriptor's registration from the reactor.
131 BOOST_ASIO_DECL void deregister_internal_descriptor(
132 socket_type descriptor, per_descriptor_data& descriptor_data);
133
134 // Add a new timer queue to the reactor.
135 template <typename Time_Traits>
136 void add_timer_queue(timer_queue<Time_Traits>& timer_queue);
137
138 // Remove a timer queue from the reactor.
139 template <typename Time_Traits>
140 void remove_timer_queue(timer_queue<Time_Traits>& timer_queue);
141
142 // Schedule a new operation in the given timer queue to expire at the
143 // specified absolute time.
144 template <typename Time_Traits>
145 void schedule_timer(timer_queue<Time_Traits>& queue,
146 const typename Time_Traits::time_type& time,
147 typename timer_queue<Time_Traits>::per_timer_data& timer, wait_op* op);
148
149 // Cancel the timer operations associated with the given token. Returns the
150 // number of operations that have been posted or dispatched.
151 template <typename Time_Traits>
152 std::size_t cancel_timer(timer_queue<Time_Traits>& queue,
153 typename timer_queue<Time_Traits>::per_timer_data& timer,
154 std::size_t max_cancelled = (std::numeric_limits<std::size_t>::max)());
155
156 // Run epoll once until interrupted or events are ready to be dispatched.
157 BOOST_ASIO_DECL void run(bool block, op_queue<operation>& ops);
158
159 // Interrupt the select loop.
160 BOOST_ASIO_DECL void interrupt();
161
162private:
163 // The hint to pass to epoll_create to size its data structures.
164 enum { epoll_size = 20000 };
165
166 // Create the epoll file descriptor. Throws an exception if the descriptor
167 // cannot be created.
168 BOOST_ASIO_DECL static int do_epoll_create();
169
170 // Create the timerfd file descriptor. Does not throw.
171 BOOST_ASIO_DECL static int do_timerfd_create();
172
173 // Allocate a new descriptor state object.
174 BOOST_ASIO_DECL descriptor_state* allocate_descriptor_state();
175
176 // Free an existing descriptor state object.
177 BOOST_ASIO_DECL void free_descriptor_state(descriptor_state* s);
178
179 // Helper function to add a new timer queue.
180 BOOST_ASIO_DECL void do_add_timer_queue(timer_queue_base& queue);
181
182 // Helper function to remove a timer queue.
183 BOOST_ASIO_DECL void do_remove_timer_queue(timer_queue_base& queue);
184
185 // Called to recalculate and update the timeout.
186 BOOST_ASIO_DECL void update_timeout();
187
188 // Get the timeout value for the epoll_wait call. The timeout value is
189 // returned as a number of milliseconds. A return value of -1 indicates
190 // that epoll_wait should block indefinitely.
191 BOOST_ASIO_DECL int get_timeout();
192
193#if defined(BOOST_ASIO_HAS_TIMERFD)
194 // Get the timeout value for the timer descriptor. The return value is the
195 // flag argument to be used when calling timerfd_settime.
196 BOOST_ASIO_DECL int get_timeout(itimerspec& ts);
197#endif // defined(BOOST_ASIO_HAS_TIMERFD)
198
199 // The io_service implementation used to post completions.
200 io_service_impl& io_service_;
201
202 // Mutex to protect access to internal data.
203 mutex mutex_;
204
205 // The interrupter is used to break a blocking epoll_wait call.
206 select_interrupter interrupter_;
207
208 // The epoll file descriptor.
209 int epoll_fd_;
210
211 // The timer file descriptor.
212 int timer_fd_;
213
214 // The timer queues.
215 timer_queue_set timer_queues_;
216
217 // Whether the service has been shut down.
218 bool shutdown_;
219
220 // Mutex to protect access to the registered descriptors.
221 mutex registered_descriptors_mutex_;
222
223 // Keep track of all registered descriptors.
224 object_pool<descriptor_state> registered_descriptors_;
225
226 // Helper class to do post-perform_io cleanup.
227 struct perform_io_cleanup_on_block_exit;
228 friend struct perform_io_cleanup_on_block_exit;
229};
230
231} // namespace detail
232} // namespace asio
233} // namespace boost
234
235#include <boost/asio/detail/pop_options.hpp>
236
237#include <boost/asio/detail/impl/epoll_reactor.hpp>
238#if defined(BOOST_ASIO_HEADER_ONLY)
239# include <boost/asio/detail/impl/epoll_reactor.ipp>
240#endif // defined(BOOST_ASIO_HEADER_ONLY)
241
242#endif // defined(BOOST_ASIO_HAS_EPOLL)
243
244#endif // BOOST_ASIO_DETAIL_EPOLL_REACTOR_HPP
245

source code of boost/boost/asio/detail/epoll_reactor.hpp