Chris@16: //
Chris@16: // detail/impl/eventfd_select_interrupter.ipp
Chris@16: // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Chris@16: //
Chris@101: // Copyright (c) 2003-2015 Christopher M. Kohlhoff (chris at kohlhoff dot com)
Chris@16: // Copyright (c) 2008 Roelof Naude (roelof.naude at gmail dot com)
Chris@16: //
Chris@16: // Distributed under the Boost Software License, Version 1.0. (See accompanying
Chris@16: // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
Chris@16: //
Chris@16: 
Chris@16: #ifndef BOOST_ASIO_DETAIL_IMPL_EVENTFD_SELECT_INTERRUPTER_IPP
Chris@16: #define BOOST_ASIO_DETAIL_IMPL_EVENTFD_SELECT_INTERRUPTER_IPP
Chris@16: 
Chris@16: #if defined(_MSC_VER) && (_MSC_VER >= 1200)
Chris@16: # pragma once
Chris@16: #endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
Chris@16: 
Chris@16: #include <boost/asio/detail/config.hpp>
Chris@16: 
Chris@16: #if defined(BOOST_ASIO_HAS_EVENTFD)
Chris@16: 
Chris@16: #include <sys/stat.h>
Chris@16: #include <sys/types.h>
Chris@16: #include <fcntl.h>
Chris@16: #if __GLIBC__ == 2 && __GLIBC_MINOR__ < 8
Chris@16: # include <asm/unistd.h>
Chris@16: #else // __GLIBC__ == 2 && __GLIBC_MINOR__ < 8
Chris@16: # include <sys/eventfd.h>
Chris@16: #endif // __GLIBC__ == 2 && __GLIBC_MINOR__ < 8
Chris@16: #include <boost/asio/detail/cstdint.hpp>
Chris@16: #include <boost/asio/detail/eventfd_select_interrupter.hpp>
Chris@16: #include <boost/asio/detail/throw_error.hpp>
Chris@16: #include <boost/asio/error.hpp>
Chris@16: 
Chris@16: #include <boost/asio/detail/push_options.hpp>
Chris@16: 
Chris@16: namespace boost {
Chris@16: namespace asio {
Chris@16: namespace detail {
Chris@16: 
Chris@16: eventfd_select_interrupter::eventfd_select_interrupter()
Chris@16: {
Chris@16:   open_descriptors();
Chris@16: }
Chris@16: 
Chris@16: void eventfd_select_interrupter::open_descriptors()
Chris@16: {
Chris@16: #if __GLIBC__ == 2 && __GLIBC_MINOR__ < 8
Chris@16:   write_descriptor_ = read_descriptor_ = syscall(__NR_eventfd, 0);
Chris@16:   if (read_descriptor_ != -1)
Chris@16:   {
Chris@16:     ::fcntl(read_descriptor_, F_SETFL, O_NONBLOCK);
Chris@16:     ::fcntl(read_descriptor_, F_SETFD, FD_CLOEXEC);
Chris@16:   }
Chris@16: #else // __GLIBC__ == 2 && __GLIBC_MINOR__ < 8
Chris@16: # if defined(EFD_CLOEXEC) && defined(EFD_NONBLOCK)
Chris@16:   write_descriptor_ = read_descriptor_ =
Chris@16:     ::eventfd(0, EFD_CLOEXEC | EFD_NONBLOCK);
Chris@16: # else // defined(EFD_CLOEXEC) && defined(EFD_NONBLOCK)
Chris@16:   errno = EINVAL;
Chris@16:   write_descriptor_ = read_descriptor_ = -1;
Chris@16: # endif // defined(EFD_CLOEXEC) && defined(EFD_NONBLOCK)
Chris@16:   if (read_descriptor_ == -1 && errno == EINVAL)
Chris@16:   {
Chris@16:     write_descriptor_ = read_descriptor_ = ::eventfd(0, 0);
Chris@16:     if (read_descriptor_ != -1)
Chris@16:     {
Chris@16:       ::fcntl(read_descriptor_, F_SETFL, O_NONBLOCK);
Chris@16:       ::fcntl(read_descriptor_, F_SETFD, FD_CLOEXEC);
Chris@16:     }
Chris@16:   }
Chris@16: #endif // __GLIBC__ == 2 && __GLIBC_MINOR__ < 8
Chris@16: 
Chris@16:   if (read_descriptor_ == -1)
Chris@16:   {
Chris@16:     int pipe_fds[2];
Chris@16:     if (pipe(pipe_fds) == 0)
Chris@16:     {
Chris@16:       read_descriptor_ = pipe_fds[0];
Chris@16:       ::fcntl(read_descriptor_, F_SETFL, O_NONBLOCK);
Chris@16:       ::fcntl(read_descriptor_, F_SETFD, FD_CLOEXEC);
Chris@16:       write_descriptor_ = pipe_fds[1];
Chris@16:       ::fcntl(write_descriptor_, F_SETFL, O_NONBLOCK);
Chris@16:       ::fcntl(write_descriptor_, F_SETFD, FD_CLOEXEC);
Chris@16:     }
Chris@16:     else
Chris@16:     {
Chris@16:       boost::system::error_code ec(errno,
Chris@16:           boost::asio::error::get_system_category());
Chris@16:       boost::asio::detail::throw_error(ec, "eventfd_select_interrupter");
Chris@16:     }
Chris@16:   }
Chris@16: }
Chris@16: 
Chris@16: eventfd_select_interrupter::~eventfd_select_interrupter()
Chris@16: {
Chris@16:   close_descriptors();
Chris@16: }
Chris@16: 
Chris@16: void eventfd_select_interrupter::close_descriptors()
Chris@16: {
Chris@16:   if (write_descriptor_ != -1 && write_descriptor_ != read_descriptor_)
Chris@16:     ::close(write_descriptor_);
Chris@16:   if (read_descriptor_ != -1)
Chris@16:     ::close(read_descriptor_);
Chris@16: }
Chris@16: 
Chris@16: void eventfd_select_interrupter::recreate()
Chris@16: {
Chris@16:   close_descriptors();
Chris@16: 
Chris@16:   write_descriptor_ = -1;
Chris@16:   read_descriptor_ = -1;
Chris@16: 
Chris@16:   open_descriptors();
Chris@16: }
Chris@16: 
Chris@16: void eventfd_select_interrupter::interrupt()
Chris@16: {
Chris@16:   uint64_t counter(1UL);
Chris@16:   int result = ::write(write_descriptor_, &counter, sizeof(uint64_t));
Chris@16:   (void)result;
Chris@16: }
Chris@16: 
Chris@16: bool eventfd_select_interrupter::reset()
Chris@16: {
Chris@16:   if (write_descriptor_ == read_descriptor_)
Chris@16:   {
Chris@16:     for (;;)
Chris@16:     {
Chris@16:       // Only perform one read. The kernel maintains an atomic counter.
Chris@16:       uint64_t counter(0);
Chris@16:       errno = 0;
Chris@16:       int bytes_read = ::read(read_descriptor_, &counter, sizeof(uint64_t));
Chris@16:       if (bytes_read < 0 && errno == EINTR)
Chris@16:         continue;
Chris@16:       bool was_interrupted = (bytes_read > 0);
Chris@16:       return was_interrupted;
Chris@16:     }
Chris@16:   }
Chris@16:   else
Chris@16:   {
Chris@16:     for (;;)
Chris@16:     {
Chris@16:       // Clear all data from the pipe.
Chris@16:       char data[1024];
Chris@16:       int bytes_read = ::read(read_descriptor_, data, sizeof(data));
Chris@16:       if (bytes_read < 0 && errno == EINTR)
Chris@16:         continue;
Chris@16:       bool was_interrupted = (bytes_read > 0);
Chris@16:       while (bytes_read == sizeof(data))
Chris@16:         bytes_read = ::read(read_descriptor_, data, sizeof(data));
Chris@16:       return was_interrupted;
Chris@16:     }
Chris@16:   }
Chris@16: }
Chris@16: 
Chris@16: } // namespace detail
Chris@16: } // namespace asio
Chris@16: } // namespace boost
Chris@16: 
Chris@16: #include <boost/asio/detail/pop_options.hpp>
Chris@16: 
Chris@16: #endif // defined(BOOST_ASIO_HAS_EVENTFD)
Chris@16: 
Chris@16: #endif // BOOST_ASIO_DETAIL_IMPL_EVENTFD_SELECT_INTERRUPTER_IPP