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- //
- // detail/impl/descriptor_ops.ipp
- // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
- //
- // Copyright (c) 2003-2019 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_DESCRIPTOR_OPS_IPP
- #define BOOST_ASIO_DETAIL_IMPL_DESCRIPTOR_OPS_IPP
- #if defined(_MSC_VER) && (_MSC_VER >= 1200)
- # pragma once
- #endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
- #include <boost/asio/detail/config.hpp>
- #include <cerrno>
- #include <boost/asio/detail/descriptor_ops.hpp>
- #include <boost/asio/error.hpp>
- #if !defined(BOOST_ASIO_WINDOWS) \
- && !defined(BOOST_ASIO_WINDOWS_RUNTIME) \
- && !defined(__CYGWIN__)
- #include <boost/asio/detail/push_options.hpp>
- namespace boost {
- namespace asio {
- namespace detail {
- namespace descriptor_ops {
- int open(const char* path, int flags, boost::system::error_code& ec)
- {
- errno = 0;
- int result = error_wrapper(::open(path, flags), ec);
- if (result >= 0)
- ec = boost::system::error_code();
- return result;
- }
- int close(int d, state_type& state, boost::system::error_code& ec)
- {
- int result = 0;
- if (d != -1)
- {
- errno = 0;
- result = error_wrapper(::close(d), ec);
- if (result != 0
- && (ec == boost::asio::error::would_block
- || ec == boost::asio::error::try_again))
- {
- // According to UNIX Network Programming Vol. 1, it is possible for
- // close() to fail with EWOULDBLOCK under certain circumstances. What
- // isn't clear is the state of the descriptor after this error. The one
- // current OS where this behaviour is seen, Windows, says that the socket
- // remains open. Therefore we'll put the descriptor back into blocking
- // mode and have another attempt at closing it.
- #if defined(__SYMBIAN32__)
- int flags = ::fcntl(d, F_GETFL, 0);
- if (flags >= 0)
- ::fcntl(d, F_SETFL, flags & ~O_NONBLOCK);
- #else // defined(__SYMBIAN32__)
- ioctl_arg_type arg = 0;
- ::ioctl(d, FIONBIO, &arg);
- #endif // defined(__SYMBIAN32__)
- state &= ~non_blocking;
- errno = 0;
- result = error_wrapper(::close(d), ec);
- }
- }
- if (result == 0)
- ec = boost::system::error_code();
- return result;
- }
- bool set_user_non_blocking(int d, state_type& state,
- bool value, boost::system::error_code& ec)
- {
- if (d == -1)
- {
- ec = boost::asio::error::bad_descriptor;
- return false;
- }
- errno = 0;
- #if defined(__SYMBIAN32__)
- int result = error_wrapper(::fcntl(d, F_GETFL, 0), ec);
- if (result >= 0)
- {
- errno = 0;
- int flag = (value ? (result | O_NONBLOCK) : (result & ~O_NONBLOCK));
- result = error_wrapper(::fcntl(d, F_SETFL, flag), ec);
- }
- #else // defined(__SYMBIAN32__)
- ioctl_arg_type arg = (value ? 1 : 0);
- int result = error_wrapper(::ioctl(d, FIONBIO, &arg), ec);
- #endif // defined(__SYMBIAN32__)
- if (result >= 0)
- {
- ec = boost::system::error_code();
- if (value)
- state |= user_set_non_blocking;
- else
- {
- // Clearing the user-set non-blocking mode always overrides any
- // internally-set non-blocking flag. Any subsequent asynchronous
- // operations will need to re-enable non-blocking I/O.
- state &= ~(user_set_non_blocking | internal_non_blocking);
- }
- return true;
- }
- return false;
- }
- bool set_internal_non_blocking(int d, state_type& state,
- bool value, boost::system::error_code& ec)
- {
- if (d == -1)
- {
- ec = boost::asio::error::bad_descriptor;
- return false;
- }
- if (!value && (state & user_set_non_blocking))
- {
- // It does not make sense to clear the internal non-blocking flag if the
- // user still wants non-blocking behaviour. Return an error and let the
- // caller figure out whether to update the user-set non-blocking flag.
- ec = boost::asio::error::invalid_argument;
- return false;
- }
- errno = 0;
- #if defined(__SYMBIAN32__)
- int result = error_wrapper(::fcntl(d, F_GETFL, 0), ec);
- if (result >= 0)
- {
- errno = 0;
- int flag = (value ? (result | O_NONBLOCK) : (result & ~O_NONBLOCK));
- result = error_wrapper(::fcntl(d, F_SETFL, flag), ec);
- }
- #else // defined(__SYMBIAN32__)
- ioctl_arg_type arg = (value ? 1 : 0);
- int result = error_wrapper(::ioctl(d, FIONBIO, &arg), ec);
- #endif // defined(__SYMBIAN32__)
- if (result >= 0)
- {
- ec = boost::system::error_code();
- if (value)
- state |= internal_non_blocking;
- else
- state &= ~internal_non_blocking;
- return true;
- }
- return false;
- }
- std::size_t sync_read(int d, state_type state, buf* bufs,
- std::size_t count, bool all_empty, boost::system::error_code& ec)
- {
- if (d == -1)
- {
- ec = boost::asio::error::bad_descriptor;
- return 0;
- }
- // A request to read 0 bytes on a stream is a no-op.
- if (all_empty)
- {
- ec = boost::system::error_code();
- return 0;
- }
- // Read some data.
- for (;;)
- {
- // Try to complete the operation without blocking.
- errno = 0;
- signed_size_type bytes = error_wrapper(::readv(
- d, bufs, static_cast<int>(count)), ec);
- // Check if operation succeeded.
- if (bytes > 0)
- return bytes;
- // Check for EOF.
- if (bytes == 0)
- {
- ec = boost::asio::error::eof;
- return 0;
- }
- // Operation failed.
- if ((state & user_set_non_blocking)
- || (ec != boost::asio::error::would_block
- && ec != boost::asio::error::try_again))
- return 0;
- // Wait for descriptor to become ready.
- if (descriptor_ops::poll_read(d, 0, ec) < 0)
- return 0;
- }
- }
- bool non_blocking_read(int d, buf* bufs, std::size_t count,
- boost::system::error_code& ec, std::size_t& bytes_transferred)
- {
- for (;;)
- {
- // Read some data.
- errno = 0;
- signed_size_type bytes = error_wrapper(::readv(
- d, bufs, static_cast<int>(count)), ec);
- // Check for end of stream.
- if (bytes == 0)
- {
- ec = boost::asio::error::eof;
- return true;
- }
- // Retry operation if interrupted by signal.
- if (ec == boost::asio::error::interrupted)
- continue;
- // Check if we need to run the operation again.
- if (ec == boost::asio::error::would_block
- || ec == boost::asio::error::try_again)
- return false;
- // Operation is complete.
- if (bytes > 0)
- {
- ec = boost::system::error_code();
- bytes_transferred = bytes;
- }
- else
- bytes_transferred = 0;
- return true;
- }
- }
- std::size_t sync_write(int d, state_type state, const buf* bufs,
- std::size_t count, bool all_empty, boost::system::error_code& ec)
- {
- if (d == -1)
- {
- ec = boost::asio::error::bad_descriptor;
- return 0;
- }
- // A request to write 0 bytes on a stream is a no-op.
- if (all_empty)
- {
- ec = boost::system::error_code();
- return 0;
- }
- // Write some data.
- for (;;)
- {
- // Try to complete the operation without blocking.
- errno = 0;
- signed_size_type bytes = error_wrapper(::writev(
- d, bufs, static_cast<int>(count)), ec);
- // Check if operation succeeded.
- if (bytes > 0)
- return bytes;
- // Operation failed.
- if ((state & user_set_non_blocking)
- || (ec != boost::asio::error::would_block
- && ec != boost::asio::error::try_again))
- return 0;
- // Wait for descriptor to become ready.
- if (descriptor_ops::poll_write(d, 0, ec) < 0)
- return 0;
- }
- }
- bool non_blocking_write(int d, const buf* bufs, std::size_t count,
- boost::system::error_code& ec, std::size_t& bytes_transferred)
- {
- for (;;)
- {
- // Write some data.
- errno = 0;
- signed_size_type bytes = error_wrapper(::writev(
- d, bufs, static_cast<int>(count)), ec);
- // Retry operation if interrupted by signal.
- if (ec == boost::asio::error::interrupted)
- continue;
- // Check if we need to run the operation again.
- if (ec == boost::asio::error::would_block
- || ec == boost::asio::error::try_again)
- return false;
- // Operation is complete.
- if (bytes >= 0)
- {
- ec = boost::system::error_code();
- bytes_transferred = bytes;
- }
- else
- bytes_transferred = 0;
- return true;
- }
- }
- int ioctl(int d, state_type& state, long cmd,
- ioctl_arg_type* arg, boost::system::error_code& ec)
- {
- if (d == -1)
- {
- ec = boost::asio::error::bad_descriptor;
- return -1;
- }
- errno = 0;
- int result = error_wrapper(::ioctl(d, cmd, arg), ec);
- if (result >= 0)
- {
- ec = boost::system::error_code();
- // When updating the non-blocking mode we always perform the ioctl syscall,
- // even if the flags would otherwise indicate that the descriptor is
- // already in the correct state. This ensures that the underlying
- // descriptor is put into the state that has been requested by the user. If
- // the ioctl syscall was successful then we need to update the flags to
- // match.
- if (cmd == static_cast<long>(FIONBIO))
- {
- if (*arg)
- {
- state |= user_set_non_blocking;
- }
- else
- {
- // Clearing the non-blocking mode always overrides any internally-set
- // non-blocking flag. Any subsequent asynchronous operations will need
- // to re-enable non-blocking I/O.
- state &= ~(user_set_non_blocking | internal_non_blocking);
- }
- }
- }
- return result;
- }
- int fcntl(int d, int cmd, boost::system::error_code& ec)
- {
- if (d == -1)
- {
- ec = boost::asio::error::bad_descriptor;
- return -1;
- }
- errno = 0;
- int result = error_wrapper(::fcntl(d, cmd), ec);
- if (result != -1)
- ec = boost::system::error_code();
- return result;
- }
- int fcntl(int d, int cmd, long arg, boost::system::error_code& ec)
- {
- if (d == -1)
- {
- ec = boost::asio::error::bad_descriptor;
- return -1;
- }
- errno = 0;
- int result = error_wrapper(::fcntl(d, cmd, arg), ec);
- if (result != -1)
- ec = boost::system::error_code();
- return result;
- }
- int poll_read(int d, state_type state, boost::system::error_code& ec)
- {
- if (d == -1)
- {
- ec = boost::asio::error::bad_descriptor;
- return -1;
- }
- pollfd fds;
- fds.fd = d;
- fds.events = POLLIN;
- fds.revents = 0;
- int timeout = (state & user_set_non_blocking) ? 0 : -1;
- errno = 0;
- int result = error_wrapper(::poll(&fds, 1, timeout), ec);
- if (result == 0)
- ec = (state & user_set_non_blocking)
- ? boost::asio::error::would_block : boost::system::error_code();
- else if (result > 0)
- ec = boost::system::error_code();
- return result;
- }
- int poll_write(int d, state_type state, boost::system::error_code& ec)
- {
- if (d == -1)
- {
- ec = boost::asio::error::bad_descriptor;
- return -1;
- }
- pollfd fds;
- fds.fd = d;
- fds.events = POLLOUT;
- fds.revents = 0;
- int timeout = (state & user_set_non_blocking) ? 0 : -1;
- errno = 0;
- int result = error_wrapper(::poll(&fds, 1, timeout), ec);
- if (result == 0)
- ec = (state & user_set_non_blocking)
- ? boost::asio::error::would_block : boost::system::error_code();
- else if (result > 0)
- ec = boost::system::error_code();
- return result;
- }
- int poll_error(int d, state_type state, boost::system::error_code& ec)
- {
- if (d == -1)
- {
- ec = boost::asio::error::bad_descriptor;
- return -1;
- }
- pollfd fds;
- fds.fd = d;
- fds.events = POLLPRI | POLLERR | POLLHUP;
- fds.revents = 0;
- int timeout = (state & user_set_non_blocking) ? 0 : -1;
- errno = 0;
- int result = error_wrapper(::poll(&fds, 1, timeout), ec);
- if (result == 0)
- ec = (state & user_set_non_blocking)
- ? boost::asio::error::would_block : boost::system::error_code();
- else if (result > 0)
- ec = boost::system::error_code();
- return result;
- }
- } // namespace descriptor_ops
- } // namespace detail
- } // namespace asio
- } // namespace boost
- #include <boost/asio/detail/pop_options.hpp>
- #endif // !defined(BOOST_ASIO_WINDOWS)
- // && !defined(BOOST_ASIO_WINDOWS_RUNTIME)
- // && !defined(__CYGWIN__)
- #endif // BOOST_ASIO_DETAIL_IMPL_DESCRIPTOR_OPS_IPP
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