| // |
| // detail/impl/eventfd_select_interrupter.ipp |
| // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |
| // |
| // Copyright (c) 2003-2011 Christopher M. Kohlhoff (chris at kohlhoff dot com) |
| // Copyright (c) 2008 Roelof Naude (roelof.naude at gmail 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_EVENTFD_SELECT_INTERRUPTER_IPP |
| #define BOOST_ASIO_DETAIL_IMPL_EVENTFD_SELECT_INTERRUPTER_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_EVENTFD) |
| |
| #include <sys/stat.h> |
| #include <sys/types.h> |
| #include <fcntl.h> |
| #if __GLIBC__ == 2 && __GLIBC_MINOR__ < 8 |
| # include <asm/unistd.h> |
| #else // __GLIBC__ == 2 && __GLIBC_MINOR__ < 8 |
| # include <sys/eventfd.h> |
| #endif // __GLIBC__ == 2 && __GLIBC_MINOR__ < 8 |
| #include <boost/asio/detail/eventfd_select_interrupter.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 { |
| |
| eventfd_select_interrupter::eventfd_select_interrupter() |
| { |
| open_descriptors(); |
| } |
| |
| void eventfd_select_interrupter::open_descriptors() |
| { |
| #if __GLIBC__ == 2 && __GLIBC_MINOR__ < 8 |
| write_descriptor_ = read_descriptor_ = syscall(__NR_eventfd, 0); |
| if (read_descriptor_ != -1) |
| { |
| ::fcntl(read_descriptor_, F_SETFL, O_NONBLOCK); |
| ::fcntl(read_descriptor_, F_SETFD, FD_CLOEXEC); |
| } |
| #else // __GLIBC__ == 2 && __GLIBC_MINOR__ < 8 |
| # if defined(EFD_CLOEXEC) && defined(EFD_NONBLOCK) |
| write_descriptor_ = read_descriptor_ = |
| ::eventfd(0, EFD_CLOEXEC | EFD_NONBLOCK); |
| # else // defined(EFD_CLOEXEC) && defined(EFD_NONBLOCK) |
| errno = EINVAL; |
| write_descriptor_ = read_descriptor_ = -1; |
| # endif // defined(EFD_CLOEXEC) && defined(EFD_NONBLOCK) |
| if (read_descriptor_ == -1 && errno == EINVAL) |
| { |
| write_descriptor_ = read_descriptor_ = ::eventfd(0, 0); |
| if (read_descriptor_ != -1) |
| { |
| ::fcntl(read_descriptor_, F_SETFL, O_NONBLOCK); |
| ::fcntl(read_descriptor_, F_SETFD, FD_CLOEXEC); |
| } |
| } |
| #endif // __GLIBC__ == 2 && __GLIBC_MINOR__ < 8 |
| |
| if (read_descriptor_ == -1) |
| { |
| int pipe_fds[2]; |
| if (pipe(pipe_fds) == 0) |
| { |
| read_descriptor_ = pipe_fds[0]; |
| ::fcntl(read_descriptor_, F_SETFL, O_NONBLOCK); |
| ::fcntl(read_descriptor_, F_SETFD, FD_CLOEXEC); |
| write_descriptor_ = pipe_fds[1]; |
| ::fcntl(write_descriptor_, F_SETFL, O_NONBLOCK); |
| ::fcntl(write_descriptor_, F_SETFD, FD_CLOEXEC); |
| } |
| else |
| { |
| boost::system::error_code ec(errno, |
| boost::asio::error::get_system_category()); |
| boost::asio::detail::throw_error(ec, "eventfd_select_interrupter"); |
| } |
| } |
| } |
| |
| eventfd_select_interrupter::~eventfd_select_interrupter() |
| { |
| close_descriptors(); |
| } |
| |
| void eventfd_select_interrupter::close_descriptors() |
| { |
| if (write_descriptor_ != -1 && write_descriptor_ != read_descriptor_) |
| ::close(write_descriptor_); |
| if (read_descriptor_ != -1) |
| ::close(read_descriptor_); |
| } |
| |
| void eventfd_select_interrupter::recreate() |
| { |
| close_descriptors(); |
| |
| write_descriptor_ = -1; |
| read_descriptor_ = -1; |
| |
| open_descriptors(); |
| } |
| |
| void eventfd_select_interrupter::interrupt() |
| { |
| uint64_t counter(1UL); |
| int result = ::write(write_descriptor_, &counter, sizeof(uint64_t)); |
| (void)result; |
| } |
| |
| bool eventfd_select_interrupter::reset() |
| { |
| if (write_descriptor_ == read_descriptor_) |
| { |
| for (;;) |
| { |
| // Only perform one read. The kernel maintains an atomic counter. |
| uint64_t counter(0); |
| errno = 0; |
| int bytes_read = ::read(read_descriptor_, &counter, sizeof(uint64_t)); |
| if (bytes_read < 0 && errno == EINTR) |
| continue; |
| bool was_interrupted = (bytes_read > 0); |
| return was_interrupted; |
| } |
| } |
| else |
| { |
| for (;;) |
| { |
| // Clear all data from the pipe. |
| char data[1024]; |
| int bytes_read = ::read(read_descriptor_, data, sizeof(data)); |
| if (bytes_read < 0 && errno == EINTR) |
| continue; |
| bool was_interrupted = (bytes_read > 0); |
| while (bytes_read == sizeof(data)) |
| bytes_read = ::read(read_descriptor_, data, sizeof(data)); |
| return was_interrupted; |
| } |
| } |
| } |
| |
| } // namespace detail |
| } // namespace asio |
| } // namespace boost |
| |
| #include <boost/asio/detail/pop_options.hpp> |
| |
| #endif // defined(BOOST_ASIO_HAS_EVENTFD) |
| |
| #endif // BOOST_ASIO_DETAIL_IMPL_EVENTFD_SELECT_INTERRUPTER_IPP |