detail/impl/select_reactor.ipp

0001 //
0002 // detail/impl/select_reactor.ipp
0003 // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
0004 //
0005 // Copyright (c) 2003-2023 Christopher M. Kohlhoff (chris at kohlhoff dot com)
0006 //
0007 // Distributed under the Boost Software License, Version 1.0. (See accompanying
0008 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
0009 //
0010
0011 #ifndef BOOST_ASIO_DETAIL_IMPL_SELECT_REACTOR_IPP
0012 #define BOOST_ASIO_DETAIL_IMPL_SELECT_REACTOR_IPP
0013
0014 #if defined(_MSC_VER) && (_MSC_VER >= 1200)
0015 # pragma once
0016 #endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
0017
0018 #include <boost/asio/detail/config.hpp>
0019
0020 #if defined(BOOST_ASIO_HAS_IOCP) \
0021   || (!defined(BOOST_ASIO_HAS_DEV_POLL) \
0022       && !defined(BOOST_ASIO_HAS_EPOLL) \
0023       && !defined(BOOST_ASIO_HAS_KQUEUE) \
0024       && !defined(BOOST_ASIO_WINDOWS_RUNTIME))
0025
0026 #include <boost/asio/detail/fd_set_adapter.hpp>
0027 #include <boost/asio/detail/select_reactor.hpp>
0028 #include <boost/asio/detail/signal_blocker.hpp>
0029 #include <boost/asio/detail/socket_ops.hpp>
0030
0031 #if defined(BOOST_ASIO_HAS_IOCP)
0032 # include <boost/asio/detail/win_iocp_io_context.hpp>
0033 #else // defined(BOOST_ASIO_HAS_IOCP)
0034 # include <boost/asio/detail/scheduler.hpp>
0035 #endif // defined(BOOST_ASIO_HAS_IOCP)
0036
0037 #include <boost/asio/detail/push_options.hpp>
0038
0039 namespace boost {
0040 namespace asio {
0041 namespace detail {
0042
0043 #if defined(BOOST_ASIO_HAS_IOCP)
0044 class select_reactor::thread_function
0045 {
0046 public:
0047   explicit thread_function(select_reactor* r)
0048     : this_(r)
0049   {
0050   }
0051
0052   void operator()()
0053   {
0054     this_->run_thread();
0055   }
0056
0057 private:
0058   select_reactor* this_;
0059 };
0060 #endif // defined(BOOST_ASIO_HAS_IOCP)
0061
0062 select_reactor::select_reactor(boost::asio::execution_context& ctx)
0063   : execution_context_service_base<select_reactor>(ctx),
0064     scheduler_(use_service<scheduler_type>(ctx)),
0065     mutex_(),
0066     interrupter_(),
0067 #if defined(BOOST_ASIO_HAS_IOCP)
0068     stop_thread_(false),
0069     thread_(0),
0070     restart_reactor_(this),
0071 #endif // defined(BOOST_ASIO_HAS_IOCP)
0072     shutdown_(false)
0073 {
0074 #if defined(BOOST_ASIO_HAS_IOCP)
0075   boost::asio::detail::signal_blocker sb;
0076   thread_ = new boost::asio::detail::thread(thread_function(this));
0077 #endif // defined(BOOST_ASIO_HAS_IOCP)
0078 }
0079
0080 select_reactor::~select_reactor()
0081 {
0082   shutdown();
0083 }
0084
0085 void select_reactor::shutdown()
0086 {
0087   boost::asio::detail::mutex::scoped_lock lock(mutex_);
0088   shutdown_ = true;
0089 #if defined(BOOST_ASIO_HAS_IOCP)
0090   stop_thread_ = true;
0091   if (thread_)
0092     interrupter_.interrupt();
0093 #endif // defined(BOOST_ASIO_HAS_IOCP)
0094   lock.unlock();
0095
0096 #if defined(BOOST_ASIO_HAS_IOCP)
0097   if (thread_)
0098   {
0099     thread_->join();
0100     delete thread_;
0101     thread_ = 0;
0102   }
0103 #endif // defined(BOOST_ASIO_HAS_IOCP)
0104
0105   op_queue<operation> ops;
0106
0107   for (int i = 0; i < max_ops; ++i)
0108     op_queue_[i].get_all_operations(ops);
0109
0110   timer_queues_.get_all_timers(ops);
0111
0112   scheduler_.abandon_operations(ops);
0113 }
0114
0115 void select_reactor::notify_fork(
0116     boost::asio::execution_context::fork_event fork_ev)
0117 {
0118 #if defined(BOOST_ASIO_HAS_IOCP)
0119   (void)fork_ev;
0120 #else // defined(BOOST_ASIO_HAS_IOCP)
0121   if (fork_ev == boost::asio::execution_context::fork_child)
0122     interrupter_.recreate();
0123 #endif // defined(BOOST_ASIO_HAS_IOCP)
0124 }
0125
0126 void select_reactor::init_task()
0127 {
0128   scheduler_.init_task();
0129 }
0130
0131 int select_reactor::register_descriptor(socket_type,
0132     select_reactor::per_descriptor_data&)
0133 {
0134   return 0;
0135 }
0136
0137 int select_reactor::register_internal_descriptor(
0138     int op_type, socket_type descriptor,
0139     select_reactor::per_descriptor_data&, reactor_op* op)
0140 {
0141   boost::asio::detail::mutex::scoped_lock lock(mutex_);
0142
0143   op_queue_[op_type].enqueue_operation(descriptor, op);
0144   interrupter_.interrupt();
0145
0146   return 0;
0147 }
0148
0149 void select_reactor::move_descriptor(socket_type,
0150     select_reactor::per_descriptor_data&,
0151     select_reactor::per_descriptor_data&)
0152 {
0153 }
0154
0155 void select_reactor::call_post_immediate_completion(
0156     operation* op, bool is_continuation, const void* self)
0157 {
0158   static_cast<const select_reactor*>(self)->post_immediate_completion(
0159       op, is_continuation);
0160 }
0161
0162 void select_reactor::start_op(int op_type, socket_type descriptor,
0163     select_reactor::per_descriptor_data&, reactor_op* op, bool is_continuation,
0164     bool, void (*on_immediate)(operation*, bool, const void*),
0165     const void* immediate_arg)
0166 {
0167   boost::asio::detail::mutex::scoped_lock lock(mutex_);
0168
0169   if (shutdown_)
0170   {
0171     on_immediate(op, is_continuation, immediate_arg);
0172     return;
0173   }
0174
0175   bool first = op_queue_[op_type].enqueue_operation(descriptor, op);
0176   scheduler_.work_started();
0177   if (first)
0178     interrupter_.interrupt();
0179 }
0180
0181 void select_reactor::cancel_ops(socket_type descriptor,
0182     select_reactor::per_descriptor_data&)
0183 {
0184   boost::asio::detail::mutex::scoped_lock lock(mutex_);
0185   cancel_ops_unlocked(descriptor, boost::asio::error::operation_aborted);
0186 }
0187
0188 void select_reactor::cancel_ops_by_key(socket_type descriptor,
0189     select_reactor::per_descriptor_data&,
0190     int op_type, void* cancellation_key)
0191 {
0192   boost::asio::detail::mutex::scoped_lock lock(mutex_);
0193   op_queue<operation> ops;
0194   bool need_interrupt = op_queue_[op_type].cancel_operations_by_key(
0195       descriptor, ops, cancellation_key, boost::asio::error::operation_aborted);
0196   scheduler_.post_deferred_completions(ops);
0197   if (need_interrupt)
0198     interrupter_.interrupt();
0199 }
0200
0201 void select_reactor::deregister_descriptor(socket_type descriptor,
0202     select_reactor::per_descriptor_data&, bool)
0203 {
0204   boost::asio::detail::mutex::scoped_lock lock(mutex_);
0205   cancel_ops_unlocked(descriptor, boost::asio::error::operation_aborted);
0206 }
0207
0208 void select_reactor::deregister_internal_descriptor(
0209     socket_type descriptor, select_reactor::per_descriptor_data&)
0210 {
0211   boost::asio::detail::mutex::scoped_lock lock(mutex_);
0212   op_queue<operation> ops;
0213   for (int i = 0; i < max_ops; ++i)
0214     op_queue_[i].cancel_operations(descriptor, ops);
0215 }
0216
0217 void select_reactor::cleanup_descriptor_data(
0218     select_reactor::per_descriptor_data&)
0219 {
0220 }
0221
0222 void select_reactor::run(long usec, op_queue<operation>& ops)
0223 {
0224   boost::asio::detail::mutex::scoped_lock lock(mutex_);
0225
0226 #if defined(BOOST_ASIO_HAS_IOCP)
0227   // Check if the thread is supposed to stop.
0228   if (stop_thread_)
0229     return;
0230 #endif // defined(BOOST_ASIO_HAS_IOCP)
0231
0232   // Set up the descriptor sets.
0233   for (int i = 0; i < max_select_ops; ++i)
0234     fd_sets_[i].reset();
0235   fd_sets_[read_op].set(interrupter_.read_descriptor());
0236   socket_type max_fd = 0;
0237   bool have_work_to_do = !timer_queues_.all_empty();
0238   for (int i = 0; i < max_select_ops; ++i)
0239   {
0240     have_work_to_do = have_work_to_do || !op_queue_[i].empty();
0241     fd_sets_[i].set(op_queue_[i], ops);
0242     if (fd_sets_[i].max_descriptor() > max_fd)
0243       max_fd = fd_sets_[i].max_descriptor();
0244   }
0245
0246 #if defined(BOOST_ASIO_WINDOWS) || defined(__CYGWIN__)
0247   // Connection operations on Windows use both except and write fd_sets.
0248   have_work_to_do = have_work_to_do || !op_queue_[connect_op].empty();
0249   fd_sets_[write_op].set(op_queue_[connect_op], ops);
0250   if (fd_sets_[write_op].max_descriptor() > max_fd)
0251     max_fd = fd_sets_[write_op].max_descriptor();
0252   fd_sets_[except_op].set(op_queue_[connect_op], ops);
0253   if (fd_sets_[except_op].max_descriptor() > max_fd)
0254     max_fd = fd_sets_[except_op].max_descriptor();
0255 #endif // defined(BOOST_ASIO_WINDOWS) || defined(__CYGWIN__)
0256
0257   // We can return immediately if there's no work to do and the reactor is
0258   // not supposed to block.
0259   if (!usec && !have_work_to_do)
0260     return;
0261
0262   // Determine how long to block while waiting for events.
0263   timeval tv_buf = { 0, 0 };
0264   timeval* tv = usec ? get_timeout(usec, tv_buf) : &tv_buf;
0265
0266   lock.unlock();
0267
0268   // Block on the select call until descriptors become ready.
0269   boost::system::error_code ec;
0270   int retval = socket_ops::select(static_cast<int>(max_fd + 1),
0271       fd_sets_[read_op], fd_sets_[write_op], fd_sets_[except_op], tv, ec);
0272
0273   // Reset the interrupter.
0274   if (retval > 0 && fd_sets_[read_op].is_set(interrupter_.read_descriptor()))
0275   {
0276     if (!interrupter_.reset())
0277     {
0278       lock.lock();
0279 #if defined(BOOST_ASIO_HAS_IOCP)
0280       stop_thread_ = true;
0281       scheduler_.post_immediate_completion(&restart_reactor_, false);
0282 #else // defined(BOOST_ASIO_HAS_IOCP)
0283       interrupter_.recreate();
0284 #endif // defined(BOOST_ASIO_HAS_IOCP)
0285     }
0286     --retval;
0287   }
0288
0289   lock.lock();
0290
0291   // Dispatch all ready operations.
0292   if (retval > 0)
0293   {
0294 #if defined(BOOST_ASIO_WINDOWS) || defined(__CYGWIN__)
0295     // Connection operations on Windows use both except and write fd_sets.
0296     fd_sets_[except_op].perform(op_queue_[connect_op], ops);
0297     fd_sets_[write_op].perform(op_queue_[connect_op], ops);
0298 #endif // defined(BOOST_ASIO_WINDOWS) || defined(__CYGWIN__)
0299
0300     // Exception operations must be processed first to ensure that any
0301     // out-of-band data is read before normal data.
0302     for (int i = max_select_ops - 1; i >= 0; --i)
0303       fd_sets_[i].perform(op_queue_[i], ops);
0304   }
0305   timer_queues_.get_ready_timers(ops);
0306 }
0307
0308 void select_reactor::interrupt()
0309 {
0310   interrupter_.interrupt();
0311 }
0312
0313 #if defined(BOOST_ASIO_HAS_IOCP)
0314 void select_reactor::run_thread()
0315 {
0316   boost::asio::detail::mutex::scoped_lock lock(mutex_);
0317   while (!stop_thread_)
0318   {
0319     lock.unlock();
0320     op_queue<operation> ops;
0321     run(-1, ops);
0322     scheduler_.post_deferred_completions(ops);
0323     lock.lock();
0324   }
0325 }
0326
0327 void select_reactor::restart_reactor::do_complete(void* owner, operation* base,
0328     const boost::system::error_code& /*ec*/, std::size_t /*bytes_transferred*/)
0329 {
0330   if (owner)
0331   {
0332     select_reactor* reactor = static_cast<restart_reactor*>(base)->reactor_;
0333
0334     if (reactor->thread_)
0335     {
0336       reactor->thread_->join();
0337       delete reactor->thread_;
0338       reactor->thread_ = 0;
0339     }
0340
0341     boost::asio::detail::mutex::scoped_lock lock(reactor->mutex_);
0342     reactor->interrupter_.recreate();
0343     reactor->stop_thread_ = false;
0344     lock.unlock();
0345
0346     boost::asio::detail::signal_blocker sb;
0347     reactor->thread_ =
0348       new boost::asio::detail::thread(thread_function(reactor));
0349   }
0350 }
0351 #endif // defined(BOOST_ASIO_HAS_IOCP)
0352
0353 void select_reactor::do_add_timer_queue(timer_queue_base& queue)
0354 {
0355   mutex::scoped_lock lock(mutex_);
0356   timer_queues_.insert(&queue);
0357 }
0358
0359 void select_reactor::do_remove_timer_queue(timer_queue_base& queue)
0360 {
0361   mutex::scoped_lock lock(mutex_);
0362   timer_queues_.erase(&queue);
0363 }
0364
0365 timeval* select_reactor::get_timeout(long usec, timeval& tv)
0366 {
0367   // By default we will wait no longer than 5 minutes. This will ensure that
0368   // any changes to the system clock are detected after no longer than this.
0369   const long max_usec = 5 * 60 * 1000 * 1000;
0370   usec = timer_queues_.wait_duration_usec(
0371       (usec < 0 || max_usec < usec) ? max_usec : usec);
0372   tv.tv_sec = usec / 1000000;
0373   tv.tv_usec = usec % 1000000;
0374   return &tv;
0375 }
0376
0377 void select_reactor::cancel_ops_unlocked(socket_type descriptor,
0378     const boost::system::error_code& ec)
0379 {
0380   bool need_interrupt = false;
0381   op_queue<operation> ops;
0382   for (int i = 0; i < max_ops; ++i)
0383     need_interrupt = op_queue_[i].cancel_operations(
0384         descriptor, ops, ec) || need_interrupt;
0385   scheduler_.post_deferred_completions(ops);
0386   if (need_interrupt)
0387     interrupter_.interrupt();
0388 }
0389
0390 } // namespace detail
0391 } // namespace asio
0392 } // namespace boost
0393
0394 #include <boost/asio/detail/pop_options.hpp>
0395
0396 #endif // defined(BOOST_ASIO_HAS_IOCP)
0397        //   || (!defined(BOOST_ASIO_HAS_DEV_POLL)
0398        //       && !defined(BOOST_ASIO_HAS_EPOLL)
0399        //       && !defined(BOOST_ASIO_HAS_KQUEUE))
0400        //       && !defined(BOOST_ASIO_WINDOWS_RUNTIME))
0401
0402 #endif // BOOST_ASIO_DETAIL_IMPL_SELECT_REACTOR_IPP