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+//
+// detail/impl/dev_poll_reactor.ipp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2012 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_IMPL_DEV_POLL_REACTOR_IPP
+#define BOOST_ASIO_DETAIL_IMPL_DEV_POLL_REACTOR_IPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include <boost/asio/detail/config.hpp>
+
+#if defined(BOOST_ASIO_HAS_DEV_POLL)
+
+#include <boost/assert.hpp>
+#include <boost/asio/detail/dev_poll_reactor.hpp>
+#include <boost/asio/detail/throw_error.hpp>
+#include <boost/asio/error.hpp>
+
+#include <boost/asio/detail/push_options.hpp>
+
+namespace boost {
+namespace asio {
+namespace detail {
+
+dev_poll_reactor::dev_poll_reactor(boost::asio::io_service& io_service)
+ : boost::asio::detail::service_base<dev_poll_reactor>(io_service),
+ io_service_(use_service<io_service_impl>(io_service)),
+ mutex_(),
+ dev_poll_fd_(do_dev_poll_create()),
+ interrupter_(),
+ shutdown_(false)
+{
+ // Add the interrupter's descriptor to /dev/poll.
+ ::pollfd ev = { 0, 0, 0 };
+ ev.fd = interrupter_.read_descriptor();
+ ev.events = POLLIN | POLLERR;
+ ev.revents = 0;
+ ::write(dev_poll_fd_, &ev, sizeof(ev));
+}
+
+dev_poll_reactor::~dev_poll_reactor()
+{
+ shutdown_service();
+ ::close(dev_poll_fd_);
+}
+
+void dev_poll_reactor::shutdown_service()
+{
+ boost::asio::detail::mutex::scoped_lock lock(mutex_);
+ shutdown_ = true;
+ lock.unlock();
+
+ op_queue<operation> ops;
+
+ for (int i = 0; i < max_ops; ++i)
+ op_queue_[i].get_all_operations(ops);
+
+ timer_queues_.get_all_timers(ops);
+
+ io_service_.abandon_operations(ops);
+}
+
+// Helper class to re-register all descriptors with /dev/poll.
+class dev_poll_reactor::fork_helper
+{
+public:
+ fork_helper(dev_poll_reactor* reactor, short events)
+ : reactor_(reactor), events_(events)
+ {
+ }
+
+ bool set(int descriptor)
+ {
+ ::pollfd& ev = reactor_->add_pending_event_change(descriptor);
+ ev.events = events_;
+ return true;
+ }
+
+private:
+ dev_poll_reactor* reactor_;
+ short events_;
+};
+
+void dev_poll_reactor::fork_service(boost::asio::io_service::fork_event fork_ev)
+{
+ if (fork_ev == boost::asio::io_service::fork_child)
+ {
+ detail::mutex::scoped_lock lock(mutex_);
+
+ if (dev_poll_fd_ != -1)
+ ::close(dev_poll_fd_);
+ dev_poll_fd_ = -1;
+ dev_poll_fd_ = do_dev_poll_create();
+
+ interrupter_.recreate();
+
+ // Add the interrupter's descriptor to /dev/poll.
+ ::pollfd ev = { 0, 0, 0 };
+ ev.fd = interrupter_.read_descriptor();
+ ev.events = POLLIN | POLLERR;
+ ev.revents = 0;
+ ::write(dev_poll_fd_, &ev, sizeof(ev));
+
+ // Re-register all descriptors with /dev/poll. The changes will be written
+ // to the /dev/poll descriptor the next time the reactor is run.
+ op_queue<operation> ops;
+ fork_helper read_op_helper(this, POLLERR | POLLHUP | POLLIN);
+ op_queue_[read_op].get_descriptors(read_op_helper, ops);
+ fork_helper write_op_helper(this, POLLERR | POLLHUP | POLLOUT);
+ op_queue_[write_op].get_descriptors(write_op_helper, ops);
+ fork_helper except_op_helper(this, POLLERR | POLLHUP | POLLPRI);
+ op_queue_[except_op].get_descriptors(except_op_helper, ops);
+ interrupter_.interrupt();
+
+ // The ops op_queue will always be empty because the fork_helper's set()
+ // member function never returns false.
+ BOOST_ASSERT(ops.empty());
+ }
+}
+
+void dev_poll_reactor::init_task()
+{
+ io_service_.init_task();
+}
+
+int dev_poll_reactor::register_descriptor(socket_type, per_descriptor_data&)
+{
+ return 0;
+}
+
+int dev_poll_reactor::register_internal_descriptor(int op_type,
+ socket_type descriptor, per_descriptor_data&, reactor_op* op)
+{
+ boost::asio::detail::mutex::scoped_lock lock(mutex_);
+
+ op_queue_[op_type].enqueue_operation(descriptor, op);
+ ::pollfd& ev = add_pending_event_change(descriptor);
+ ev.events = POLLERR | POLLHUP;
+ switch (op_type)
+ {
+ case read_op: ev.events |= POLLIN; break;
+ case write_op: ev.events |= POLLOUT; break;
+ case except_op: ev.events |= POLLPRI; break;
+ default: break;
+ }
+ interrupter_.interrupt();
+
+ return 0;
+}
+
+void dev_poll_reactor::move_descriptor(socket_type,
+ dev_poll_reactor::per_descriptor_data&,
+ dev_poll_reactor::per_descriptor_data&)
+{
+}
+
+void dev_poll_reactor::start_op(int op_type, socket_type descriptor,
+ dev_poll_reactor::per_descriptor_data&,
+ reactor_op* op, bool allow_speculative)
+{
+ boost::asio::detail::mutex::scoped_lock lock(mutex_);
+
+ if (shutdown_)
+ {
+ post_immediate_completion(op);
+ return;
+ }
+
+ if (allow_speculative)
+ {
+ if (op_type != read_op || !op_queue_[except_op].has_operation(descriptor))
+ {
+ if (!op_queue_[op_type].has_operation(descriptor))
+ {
+ if (op->perform())
+ {
+ lock.unlock();
+ io_service_.post_immediate_completion(op);
+ return;
+ }
+ }
+ }
+ }
+
+ bool first = op_queue_[op_type].enqueue_operation(descriptor, op);
+ io_service_.work_started();
+ if (first)
+ {
+ ::pollfd& ev = add_pending_event_change(descriptor);
+ ev.events = POLLERR | POLLHUP;
+ if (op_type == read_op
+ || op_queue_[read_op].has_operation(descriptor))
+ ev.events |= POLLIN;
+ if (op_type == write_op
+ || op_queue_[write_op].has_operation(descriptor))
+ ev.events |= POLLOUT;
+ if (op_type == except_op
+ || op_queue_[except_op].has_operation(descriptor))
+ ev.events |= POLLPRI;
+ interrupter_.interrupt();
+ }
+}
+
+void dev_poll_reactor::cancel_ops(socket_type descriptor,
+ dev_poll_reactor::per_descriptor_data&)
+{
+ boost::asio::detail::mutex::scoped_lock lock(mutex_);
+ cancel_ops_unlocked(descriptor, boost::asio::error::operation_aborted);
+}
+
+void dev_poll_reactor::deregister_descriptor(socket_type descriptor,
+ dev_poll_reactor::per_descriptor_data&, bool)
+{
+ 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, boost::asio::error::operation_aborted);
+}
+
+void dev_poll_reactor::deregister_internal_descriptor(
+ socket_type descriptor, dev_poll_reactor::per_descriptor_data&)
+{
+ boost::asio::detail::mutex::scoped_lock lock(mutex_);
+
+ // Remove the descriptor from /dev/poll. Since this function is only called
+ // during a fork, we can apply the change immediately.
+ ::pollfd ev = { 0, 0, 0 };
+ ev.fd = descriptor;
+ ev.events = POLLREMOVE;
+ ev.revents = 0;
+ ::write(dev_poll_fd_, &ev, sizeof(ev));
+
+ // Destroy all operations associated with the descriptor.
+ op_queue<operation> ops;
+ boost::system::error_code ec;
+ for (int i = 0; i < max_ops; ++i)
+ op_queue_[i].cancel_operations(descriptor, ops, ec);
+}
+
+void dev_poll_reactor::run(bool block, op_queue<operation>& ops)
+{
+ boost::asio::detail::mutex::scoped_lock lock(mutex_);
+
+ // We can return immediately if there's no work to do and the reactor is
+ // not supposed to block.
+ if (!block && op_queue_[read_op].empty() && op_queue_[write_op].empty()
+ && op_queue_[except_op].empty() && timer_queues_.all_empty())
+ 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))
+ {
+ boost::system::error_code ec = boost::system::error_code(
+ errno, boost::asio::error::get_system_category());
+ for (std::size_t i = 0; i < pending_event_changes_.size(); ++i)
+ {
+ int descriptor = pending_event_changes_[i].fd;
+ for (int j = 0; j < max_ops; ++j)
+ op_queue_[j].cancel_operations(descriptor, ops, ec);
+ }
+ }
+ pending_event_changes_.clear();
+ pending_event_change_index_.clear();
+ }
+
+ int timeout = block ? get_timeout() : 0;
+ lock.unlock();
+
+ // Block on the /dev/poll descriptor.
+ ::pollfd events[128] = { { 0, 0, 0 } };
+ ::dvpoll dp = { 0, 0, 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();
+
+ // 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;
+
+ // 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 =
+ op_queue_[except_op].perform_operations(descriptor, ops);
+ else
+ more_except = op_queue_[except_op].has_operation(descriptor);
+
+ if (events[i].events & (POLLIN | POLLERR | POLLHUP))
+ more_reads = op_queue_[read_op].perform_operations(descriptor, ops);
+ else
+ more_reads = op_queue_[read_op].has_operation(descriptor);
+
+ if (events[i].events & (POLLOUT | POLLERR | POLLHUP))
+ more_writes = op_queue_[write_op].perform_operations(descriptor, ops);
+ else
+ more_writes = op_queue_[write_op].has_operation(descriptor);
+
+ if ((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, 0, 0 };
+ ev.fd = descriptor;
+ ev.events = POLLREMOVE;
+ ev.revents = 0;
+ ::write(dev_poll_fd_, &ev, sizeof(ev));
+ }
+ else
+ {
+ ::pollfd ev = { 0, 0, 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))
+ {
+ boost::system::error_code ec(errno,
+ boost::asio::error::get_system_category());
+ for (int j = 0; j < max_ops; ++j)
+ op_queue_[j].cancel_operations(descriptor, ops, ec);
+ }
+ }
+ }
+ }
+ timer_queues_.get_ready_timers(ops);
+}
+
+void dev_poll_reactor::interrupt()
+{
+ interrupter_.interrupt();
+}
+
+int dev_poll_reactor::do_dev_poll_create()
+{
+ int fd = ::open("/dev/poll", O_RDWR);
+ if (fd == -1)
+ {
+ boost::system::error_code ec(errno,
+ boost::asio::error::get_system_category());
+ boost::asio::detail::throw_error(ec, "/dev/poll");
+ }
+ return fd;
+}
+
+void dev_poll_reactor::do_add_timer_queue(timer_queue_base& queue)
+{
+ mutex::scoped_lock lock(mutex_);
+ timer_queues_.insert(&queue);
+}
+
+void dev_poll_reactor::do_remove_timer_queue(timer_queue_base& queue)
+{
+ mutex::scoped_lock lock(mutex_);
+ timer_queues_.erase(&queue);
+}
+
+int dev_poll_reactor::get_timeout()
+{
+ // 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.
+ return timer_queues_.wait_duration_msec(5 * 60 * 1000);
+}
+
+void dev_poll_reactor::cancel_ops_unlocked(socket_type descriptor,
+ const boost::system::error_code& ec)
+{
+ bool need_interrupt = false;
+ op_queue<operation> ops;
+ for (int i = 0; i < max_ops; ++i)
+ need_interrupt = op_queue_[i].cancel_operations(
+ descriptor, ops, ec) || need_interrupt;
+ io_service_.post_deferred_completions(ops);
+ if (need_interrupt)
+ interrupter_.interrupt();
+}
+
+::pollfd& dev_poll_reactor::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];
+ }
+}
+
+} // namespace detail
+} // namespace asio
+} // namespace boost
+
+#include <boost/asio/detail/pop_options.hpp>
+
+#endif // defined(BOOST_ASIO_HAS_DEV_POLL)
+
+#endif // BOOST_ASIO_DETAIL_IMPL_DEV_POLL_REACTOR_IPP