AngelscriptDebuggerServer/extern/asio-1.18.2/include/asio/detail/impl/epoll_reactor.ipp

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C++

//
// detail/impl/epoll_reactor.ipp
// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
//
// 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_IMPL_EPOLL_REACTOR_IPP
#define ASIO_DETAIL_IMPL_EPOLL_REACTOR_IPP
#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 <cstddef>
#include <sys/epoll.h>
#include "asio/detail/epoll_reactor.hpp"
#include "asio/detail/throw_error.hpp"
#include "asio/error.hpp"
#if defined(ASIO_HAS_TIMERFD)
# include <sys/timerfd.h>
#endif // defined(ASIO_HAS_TIMERFD)
#include "asio/detail/push_options.hpp"
namespace asio {
namespace detail {
epoll_reactor::epoll_reactor(asio::execution_context& ctx)
: execution_context_service_base<epoll_reactor>(ctx),
scheduler_(use_service<scheduler>(ctx)),
mutex_(ASIO_CONCURRENCY_HINT_IS_LOCKING(
REACTOR_REGISTRATION, scheduler_.concurrency_hint())),
interrupter_(),
epoll_fd_(do_epoll_create()),
timer_fd_(do_timerfd_create()),
shutdown_(false),
registered_descriptors_mutex_(mutex_.enabled())
{
// Add the interrupter's descriptor to epoll.
epoll_event ev = { 0, { 0 } };
ev.events = EPOLLIN | EPOLLERR | EPOLLET;
ev.data.ptr = &interrupter_;
epoll_ctl(epoll_fd_, EPOLL_CTL_ADD, interrupter_.read_descriptor(), &ev);
interrupter_.interrupt();
// Add the timer descriptor to epoll.
if (timer_fd_ != -1)
{
ev.events = EPOLLIN | EPOLLERR;
ev.data.ptr = &timer_fd_;
epoll_ctl(epoll_fd_, EPOLL_CTL_ADD, timer_fd_, &ev);
}
}
epoll_reactor::~epoll_reactor()
{
if (epoll_fd_ != -1)
close(epoll_fd_);
if (timer_fd_ != -1)
close(timer_fd_);
}
void epoll_reactor::shutdown()
{
mutex::scoped_lock lock(mutex_);
shutdown_ = true;
lock.unlock();
op_queue<operation> ops;
while (descriptor_state* state = registered_descriptors_.first())
{
for (int i = 0; i < max_ops; ++i)
ops.push(state->op_queue_[i]);
state->shutdown_ = true;
registered_descriptors_.free(state);
}
timer_queues_.get_all_timers(ops);
scheduler_.abandon_operations(ops);
}
void epoll_reactor::notify_fork(
asio::execution_context::fork_event fork_ev)
{
if (fork_ev == asio::execution_context::fork_child)
{
if (epoll_fd_ != -1)
::close(epoll_fd_);
epoll_fd_ = -1;
epoll_fd_ = do_epoll_create();
if (timer_fd_ != -1)
::close(timer_fd_);
timer_fd_ = -1;
timer_fd_ = do_timerfd_create();
interrupter_.recreate();
// Add the interrupter's descriptor to epoll.
epoll_event ev = { 0, { 0 } };
ev.events = EPOLLIN | EPOLLERR | EPOLLET;
ev.data.ptr = &interrupter_;
epoll_ctl(epoll_fd_, EPOLL_CTL_ADD, interrupter_.read_descriptor(), &ev);
interrupter_.interrupt();
// Add the timer descriptor to epoll.
if (timer_fd_ != -1)
{
ev.events = EPOLLIN | EPOLLERR;
ev.data.ptr = &timer_fd_;
epoll_ctl(epoll_fd_, EPOLL_CTL_ADD, timer_fd_, &ev);
}
update_timeout();
// Re-register all descriptors with epoll.
mutex::scoped_lock descriptors_lock(registered_descriptors_mutex_);
for (descriptor_state* state = registered_descriptors_.first();
state != 0; state = state->next_)
{
ev.events = state->registered_events_;
ev.data.ptr = state;
int result = epoll_ctl(epoll_fd_, EPOLL_CTL_ADD, state->descriptor_, &ev);
if (result != 0)
{
asio::error_code ec(errno,
asio::error::get_system_category());
asio::detail::throw_error(ec, "epoll re-registration");
}
}
}
}
void epoll_reactor::init_task()
{
scheduler_.init_task();
}
int epoll_reactor::register_descriptor(socket_type descriptor,
epoll_reactor::per_descriptor_data& descriptor_data)
{
descriptor_data = allocate_descriptor_state();
ASIO_HANDLER_REACTOR_REGISTRATION((
context(), static_cast<uintmax_t>(descriptor),
reinterpret_cast<uintmax_t>(descriptor_data)));
{
mutex::scoped_lock descriptor_lock(descriptor_data->mutex_);
descriptor_data->reactor_ = this;
descriptor_data->descriptor_ = descriptor;
descriptor_data->shutdown_ = false;
for (int i = 0; i < max_ops; ++i)
descriptor_data->try_speculative_[i] = true;
}
epoll_event ev = { 0, { 0 } };
ev.events = EPOLLIN | EPOLLERR | EPOLLHUP | EPOLLPRI | EPOLLET;
descriptor_data->registered_events_ = ev.events;
ev.data.ptr = descriptor_data;
int result = epoll_ctl(epoll_fd_, EPOLL_CTL_ADD, descriptor, &ev);
if (result != 0)
{
if (errno == EPERM)
{
// This file descriptor type is not supported by epoll. However, if it is
// a regular file then operations on it will not block. We will allow
// this descriptor to be used and fail later if an operation on it would
// otherwise require a trip through the reactor.
descriptor_data->registered_events_ = 0;
return 0;
}
return errno;
}
return 0;
}
int epoll_reactor::register_internal_descriptor(
int op_type, socket_type descriptor,
epoll_reactor::per_descriptor_data& descriptor_data, reactor_op* op)
{
descriptor_data = allocate_descriptor_state();
ASIO_HANDLER_REACTOR_REGISTRATION((
context(), static_cast<uintmax_t>(descriptor),
reinterpret_cast<uintmax_t>(descriptor_data)));
{
mutex::scoped_lock descriptor_lock(descriptor_data->mutex_);
descriptor_data->reactor_ = this;
descriptor_data->descriptor_ = descriptor;
descriptor_data->shutdown_ = false;
descriptor_data->op_queue_[op_type].push(op);
for (int i = 0; i < max_ops; ++i)
descriptor_data->try_speculative_[i] = true;
}
epoll_event ev = { 0, { 0 } };
ev.events = EPOLLIN | EPOLLERR | EPOLLHUP | EPOLLPRI | EPOLLET;
descriptor_data->registered_events_ = ev.events;
ev.data.ptr = descriptor_data;
int result = epoll_ctl(epoll_fd_, EPOLL_CTL_ADD, descriptor, &ev);
if (result != 0)
return errno;
return 0;
}
void epoll_reactor::move_descriptor(socket_type,
epoll_reactor::per_descriptor_data& target_descriptor_data,
epoll_reactor::per_descriptor_data& source_descriptor_data)
{
target_descriptor_data = source_descriptor_data;
source_descriptor_data = 0;
}
void epoll_reactor::start_op(int op_type, socket_type descriptor,
epoll_reactor::per_descriptor_data& descriptor_data, reactor_op* op,
bool is_continuation, bool allow_speculative)
{
if (!descriptor_data)
{
op->ec_ = asio::error::bad_descriptor;
post_immediate_completion(op, is_continuation);
return;
}
mutex::scoped_lock descriptor_lock(descriptor_data->mutex_);
if (descriptor_data->shutdown_)
{
post_immediate_completion(op, is_continuation);
return;
}
if (descriptor_data->op_queue_[op_type].empty())
{
if (allow_speculative
&& (op_type != read_op
|| descriptor_data->op_queue_[except_op].empty()))
{
if (descriptor_data->try_speculative_[op_type])
{
if (reactor_op::status status = op->perform())
{
if (status == reactor_op::done_and_exhausted)
if (descriptor_data->registered_events_ != 0)
descriptor_data->try_speculative_[op_type] = false;
descriptor_lock.unlock();
scheduler_.post_immediate_completion(op, is_continuation);
return;
}
}
if (descriptor_data->registered_events_ == 0)
{
op->ec_ = asio::error::operation_not_supported;
scheduler_.post_immediate_completion(op, is_continuation);
return;
}
if (op_type == write_op)
{
if ((descriptor_data->registered_events_ & EPOLLOUT) == 0)
{
epoll_event ev = { 0, { 0 } };
ev.events = descriptor_data->registered_events_ | EPOLLOUT;
ev.data.ptr = descriptor_data;
if (epoll_ctl(epoll_fd_, EPOLL_CTL_MOD, descriptor, &ev) == 0)
{
descriptor_data->registered_events_ |= ev.events;
}
else
{
op->ec_ = asio::error_code(errno,
asio::error::get_system_category());
scheduler_.post_immediate_completion(op, is_continuation);
return;
}
}
}
}
else if (descriptor_data->registered_events_ == 0)
{
op->ec_ = asio::error::operation_not_supported;
scheduler_.post_immediate_completion(op, is_continuation);
return;
}
else
{
if (op_type == write_op)
{
descriptor_data->registered_events_ |= EPOLLOUT;
}
epoll_event ev = { 0, { 0 } };
ev.events = descriptor_data->registered_events_;
ev.data.ptr = descriptor_data;
epoll_ctl(epoll_fd_, EPOLL_CTL_MOD, descriptor, &ev);
}
}
descriptor_data->op_queue_[op_type].push(op);
scheduler_.work_started();
}
void epoll_reactor::cancel_ops(socket_type,
epoll_reactor::per_descriptor_data& descriptor_data)
{
if (!descriptor_data)
return;
mutex::scoped_lock descriptor_lock(descriptor_data->mutex_);
op_queue<operation> ops;
for (int i = 0; i < max_ops; ++i)
{
while (reactor_op* op = descriptor_data->op_queue_[i].front())
{
op->ec_ = asio::error::operation_aborted;
descriptor_data->op_queue_[i].pop();
ops.push(op);
}
}
descriptor_lock.unlock();
scheduler_.post_deferred_completions(ops);
}
void epoll_reactor::deregister_descriptor(socket_type descriptor,
epoll_reactor::per_descriptor_data& descriptor_data, bool closing)
{
if (!descriptor_data)
return;
mutex::scoped_lock descriptor_lock(descriptor_data->mutex_);
if (!descriptor_data->shutdown_)
{
if (closing)
{
// The descriptor will be automatically removed from the epoll set when
// it is closed.
}
else if (descriptor_data->registered_events_ != 0)
{
epoll_event ev = { 0, { 0 } };
epoll_ctl(epoll_fd_, EPOLL_CTL_DEL, descriptor, &ev);
}
op_queue<operation> ops;
for (int i = 0; i < max_ops; ++i)
{
while (reactor_op* op = descriptor_data->op_queue_[i].front())
{
op->ec_ = asio::error::operation_aborted;
descriptor_data->op_queue_[i].pop();
ops.push(op);
}
}
descriptor_data->descriptor_ = -1;
descriptor_data->shutdown_ = true;
descriptor_lock.unlock();
ASIO_HANDLER_REACTOR_DEREGISTRATION((
context(), static_cast<uintmax_t>(descriptor),
reinterpret_cast<uintmax_t>(descriptor_data)));
scheduler_.post_deferred_completions(ops);
// Leave descriptor_data set so that it will be freed by the subsequent
// call to cleanup_descriptor_data.
}
else
{
// We are shutting down, so prevent cleanup_descriptor_data from freeing
// the descriptor_data object and let the destructor free it instead.
descriptor_data = 0;
}
}
void epoll_reactor::deregister_internal_descriptor(socket_type descriptor,
epoll_reactor::per_descriptor_data& descriptor_data)
{
if (!descriptor_data)
return;
mutex::scoped_lock descriptor_lock(descriptor_data->mutex_);
if (!descriptor_data->shutdown_)
{
epoll_event ev = { 0, { 0 } };
epoll_ctl(epoll_fd_, EPOLL_CTL_DEL, descriptor, &ev);
op_queue<operation> ops;
for (int i = 0; i < max_ops; ++i)
ops.push(descriptor_data->op_queue_[i]);
descriptor_data->descriptor_ = -1;
descriptor_data->shutdown_ = true;
descriptor_lock.unlock();
ASIO_HANDLER_REACTOR_DEREGISTRATION((
context(), static_cast<uintmax_t>(descriptor),
reinterpret_cast<uintmax_t>(descriptor_data)));
// Leave descriptor_data set so that it will be freed by the subsequent
// call to cleanup_descriptor_data.
}
else
{
// We are shutting down, so prevent cleanup_descriptor_data from freeing
// the descriptor_data object and let the destructor free it instead.
descriptor_data = 0;
}
}
void epoll_reactor::cleanup_descriptor_data(
per_descriptor_data& descriptor_data)
{
if (descriptor_data)
{
free_descriptor_state(descriptor_data);
descriptor_data = 0;
}
}
void epoll_reactor::run(long usec, op_queue<operation>& ops)
{
// This code relies on the fact that the scheduler queues the reactor task
// behind all descriptor operations generated by this function. This means,
// that by the time we reach this point, any previously returned descriptor
// operations have already been dequeued. Therefore it is now safe for us to
// reuse and return them for the scheduler to queue again.
// Calculate timeout. Check the timer queues only if timerfd is not in use.
int timeout;
if (usec == 0)
timeout = 0;
else
{
timeout = (usec < 0) ? -1 : ((usec - 1) / 1000 + 1);
if (timer_fd_ == -1)
{
mutex::scoped_lock lock(mutex_);
timeout = get_timeout(timeout);
}
}
// Block on the epoll descriptor.
epoll_event events[128];
int num_events = epoll_wait(epoll_fd_, events, 128, timeout);
#if defined(ASIO_ENABLE_HANDLER_TRACKING)
// Trace the waiting events.
for (int i = 0; i < num_events; ++i)
{
void* ptr = events[i].data.ptr;
if (ptr == &interrupter_)
{
// Ignore.
}
# if defined(ASIO_HAS_TIMERFD)
else if (ptr == &timer_fd_)
{
// Ignore.
}
# endif // defined(ASIO_HAS_TIMERFD)
else
{
unsigned event_mask = 0;
if ((events[i].events & EPOLLIN) != 0)
event_mask |= ASIO_HANDLER_REACTOR_READ_EVENT;
if ((events[i].events & EPOLLOUT))
event_mask |= ASIO_HANDLER_REACTOR_WRITE_EVENT;
if ((events[i].events & (EPOLLERR | EPOLLHUP)) != 0)
event_mask |= ASIO_HANDLER_REACTOR_ERROR_EVENT;
ASIO_HANDLER_REACTOR_EVENTS((context(),
reinterpret_cast<uintmax_t>(ptr), event_mask));
}
}
#endif // defined(ASIO_ENABLE_HANDLER_TRACKING)
#if defined(ASIO_HAS_TIMERFD)
bool check_timers = (timer_fd_ == -1);
#else // defined(ASIO_HAS_TIMERFD)
bool check_timers = true;
#endif // defined(ASIO_HAS_TIMERFD)
// Dispatch the waiting events.
for (int i = 0; i < num_events; ++i)
{
void* ptr = events[i].data.ptr;
if (ptr == &interrupter_)
{
// No need to reset the interrupter since we're leaving the descriptor
// in a ready-to-read state and relying on edge-triggered notifications
// to make it so that we only get woken up when the descriptor's epoll
// registration is updated.
#if defined(ASIO_HAS_TIMERFD)
if (timer_fd_ == -1)
check_timers = true;
#else // defined(ASIO_HAS_TIMERFD)
check_timers = true;
#endif // defined(ASIO_HAS_TIMERFD)
}
#if defined(ASIO_HAS_TIMERFD)
else if (ptr == &timer_fd_)
{
check_timers = true;
}
#endif // defined(ASIO_HAS_TIMERFD)
else
{
// The descriptor operation doesn't count as work in and of itself, so we
// don't call work_started() here. This still allows the scheduler to
// stop if the only remaining operations are descriptor operations.
descriptor_state* descriptor_data = static_cast<descriptor_state*>(ptr);
if (!ops.is_enqueued(descriptor_data))
{
descriptor_data->set_ready_events(events[i].events);
ops.push(descriptor_data);
}
else
{
descriptor_data->add_ready_events(events[i].events);
}
}
}
if (check_timers)
{
mutex::scoped_lock common_lock(mutex_);
timer_queues_.get_ready_timers(ops);
#if defined(ASIO_HAS_TIMERFD)
if (timer_fd_ != -1)
{
itimerspec new_timeout;
itimerspec old_timeout;
int flags = get_timeout(new_timeout);
timerfd_settime(timer_fd_, flags, &new_timeout, &old_timeout);
}
#endif // defined(ASIO_HAS_TIMERFD)
}
}
void epoll_reactor::interrupt()
{
epoll_event ev = { 0, { 0 } };
ev.events = EPOLLIN | EPOLLERR | EPOLLET;
ev.data.ptr = &interrupter_;
epoll_ctl(epoll_fd_, EPOLL_CTL_MOD, interrupter_.read_descriptor(), &ev);
}
int epoll_reactor::do_epoll_create()
{
#if defined(EPOLL_CLOEXEC)
int fd = epoll_create1(EPOLL_CLOEXEC);
#else // defined(EPOLL_CLOEXEC)
int fd = -1;
errno = EINVAL;
#endif // defined(EPOLL_CLOEXEC)
if (fd == -1 && (errno == EINVAL || errno == ENOSYS))
{
fd = epoll_create(epoll_size);
if (fd != -1)
::fcntl(fd, F_SETFD, FD_CLOEXEC);
}
if (fd == -1)
{
asio::error_code ec(errno,
asio::error::get_system_category());
asio::detail::throw_error(ec, "epoll");
}
return fd;
}
int epoll_reactor::do_timerfd_create()
{
#if defined(ASIO_HAS_TIMERFD)
# if defined(TFD_CLOEXEC)
int fd = timerfd_create(CLOCK_MONOTONIC, TFD_CLOEXEC);
# else // defined(TFD_CLOEXEC)
int fd = -1;
errno = EINVAL;
# endif // defined(TFD_CLOEXEC)
if (fd == -1 && errno == EINVAL)
{
fd = timerfd_create(CLOCK_MONOTONIC, 0);
if (fd != -1)
::fcntl(fd, F_SETFD, FD_CLOEXEC);
}
return fd;
#else // defined(ASIO_HAS_TIMERFD)
return -1;
#endif // defined(ASIO_HAS_TIMERFD)
}
epoll_reactor::descriptor_state* epoll_reactor::allocate_descriptor_state()
{
mutex::scoped_lock descriptors_lock(registered_descriptors_mutex_);
return registered_descriptors_.alloc(ASIO_CONCURRENCY_HINT_IS_LOCKING(
REACTOR_IO, scheduler_.concurrency_hint()));
}
void epoll_reactor::free_descriptor_state(epoll_reactor::descriptor_state* s)
{
mutex::scoped_lock descriptors_lock(registered_descriptors_mutex_);
registered_descriptors_.free(s);
}
void epoll_reactor::do_add_timer_queue(timer_queue_base& queue)
{
mutex::scoped_lock lock(mutex_);
timer_queues_.insert(&queue);
}
void epoll_reactor::do_remove_timer_queue(timer_queue_base& queue)
{
mutex::scoped_lock lock(mutex_);
timer_queues_.erase(&queue);
}
void epoll_reactor::update_timeout()
{
#if defined(ASIO_HAS_TIMERFD)
if (timer_fd_ != -1)
{
itimerspec new_timeout;
itimerspec old_timeout;
int flags = get_timeout(new_timeout);
timerfd_settime(timer_fd_, flags, &new_timeout, &old_timeout);
return;
}
#endif // defined(ASIO_HAS_TIMERFD)
interrupt();
}
int epoll_reactor::get_timeout(int msec)
{
// 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.
const int max_msec = 5 * 60 * 1000;
return timer_queues_.wait_duration_msec(
(msec < 0 || max_msec < msec) ? max_msec : msec);
}
#if defined(ASIO_HAS_TIMERFD)
int epoll_reactor::get_timeout(itimerspec& ts)
{
ts.it_interval.tv_sec = 0;
ts.it_interval.tv_nsec = 0;
long usec = timer_queues_.wait_duration_usec(5 * 60 * 1000 * 1000);
ts.it_value.tv_sec = usec / 1000000;
ts.it_value.tv_nsec = usec ? (usec % 1000000) * 1000 : 1;
return usec ? 0 : TFD_TIMER_ABSTIME;
}
#endif // defined(ASIO_HAS_TIMERFD)
struct epoll_reactor::perform_io_cleanup_on_block_exit
{
explicit perform_io_cleanup_on_block_exit(epoll_reactor* r)
: reactor_(r), first_op_(0)
{
}
~perform_io_cleanup_on_block_exit()
{
if (first_op_)
{
// Post the remaining completed operations for invocation.
if (!ops_.empty())
reactor_->scheduler_.post_deferred_completions(ops_);
// A user-initiated operation has completed, but there's no need to
// explicitly call work_finished() here. Instead, we'll take advantage of
// the fact that the scheduler will call work_finished() once we return.
}
else
{
// No user-initiated operations have completed, so we need to compensate
// for the work_finished() call that the scheduler will make once this
// operation returns.
reactor_->scheduler_.compensating_work_started();
}
}
epoll_reactor* reactor_;
op_queue<operation> ops_;
operation* first_op_;
};
epoll_reactor::descriptor_state::descriptor_state(bool locking)
: operation(&epoll_reactor::descriptor_state::do_complete),
mutex_(locking)
{
}
operation* epoll_reactor::descriptor_state::perform_io(uint32_t events)
{
mutex_.lock();
perform_io_cleanup_on_block_exit io_cleanup(reactor_);
mutex::scoped_lock descriptor_lock(mutex_, mutex::scoped_lock::adopt_lock);
// Exception operations must be processed first to ensure that any
// out-of-band data is read before normal data.
static const int flag[max_ops] = { EPOLLIN, EPOLLOUT, EPOLLPRI };
for (int j = max_ops - 1; j >= 0; --j)
{
if (events & (flag[j] | EPOLLERR | EPOLLHUP))
{
try_speculative_[j] = true;
while (reactor_op* op = op_queue_[j].front())
{
if (reactor_op::status status = op->perform())
{
op_queue_[j].pop();
io_cleanup.ops_.push(op);
if (status == reactor_op::done_and_exhausted)
{
try_speculative_[j] = false;
break;
}
}
else
break;
}
}
}
// The first operation will be returned for completion now. The others will
// be posted for later by the io_cleanup object's destructor.
io_cleanup.first_op_ = io_cleanup.ops_.front();
io_cleanup.ops_.pop();
return io_cleanup.first_op_;
}
void epoll_reactor::descriptor_state::do_complete(
void* owner, operation* base,
const asio::error_code& ec, std::size_t bytes_transferred)
{
if (owner)
{
descriptor_state* descriptor_data = static_cast<descriptor_state*>(base);
uint32_t events = static_cast<uint32_t>(bytes_transferred);
if (operation* op = descriptor_data->perform_io(events))
{
op->complete(owner, ec, 0);
}
}
}
} // namespace detail
} // namespace asio
#include "asio/detail/pop_options.hpp"
#endif // defined(ASIO_HAS_EPOLL)
#endif // ASIO_DETAIL_IMPL_EPOLL_REACTOR_IPP