Chris@16: //
Chris@16: // detail/impl/descriptor_ops.ipp
Chris@16: // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Chris@16: //
Chris@101: // Copyright (c) 2003-2015 Christopher M. Kohlhoff (chris at kohlhoff 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_DESCRIPTOR_OPS_IPP
Chris@16: #define BOOST_ASIO_DETAIL_IMPL_DESCRIPTOR_OPS_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: #include <cerrno>
Chris@16: #include <boost/asio/detail/descriptor_ops.hpp>
Chris@16: #include <boost/asio/error.hpp>
Chris@16: 
Chris@16: #if !defined(BOOST_ASIO_WINDOWS) \
Chris@16:   && !defined(BOOST_ASIO_WINDOWS_RUNTIME) \
Chris@16:   && !defined(__CYGWIN__)
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: namespace descriptor_ops {
Chris@16: 
Chris@16: int open(const char* path, int flags, boost::system::error_code& ec)
Chris@16: {
Chris@16:   errno = 0;
Chris@16:   int result = error_wrapper(::open(path, flags), ec);
Chris@16:   if (result >= 0)
Chris@16:     ec = boost::system::error_code();
Chris@16:   return result;
Chris@16: }
Chris@16: 
Chris@16: int close(int d, state_type& state, boost::system::error_code& ec)
Chris@16: {
Chris@16:   int result = 0;
Chris@16:   if (d != -1)
Chris@16:   {
Chris@16:     errno = 0;
Chris@16:     result = error_wrapper(::close(d), ec);
Chris@16: 
Chris@16:     if (result != 0
Chris@16:         && (ec == boost::asio::error::would_block
Chris@16:           || ec == boost::asio::error::try_again))
Chris@16:     {
Chris@16:       // According to UNIX Network Programming Vol. 1, it is possible for
Chris@16:       // close() to fail with EWOULDBLOCK under certain circumstances. What
Chris@16:       // isn't clear is the state of the descriptor after this error. The one
Chris@16:       // current OS where this behaviour is seen, Windows, says that the socket
Chris@16:       // remains open. Therefore we'll put the descriptor back into blocking
Chris@16:       // mode and have another attempt at closing it.
Chris@16: #if defined(__SYMBIAN32__)
Chris@16:       int flags = ::fcntl(d, F_GETFL, 0);
Chris@16:       if (flags >= 0)
Chris@16:         ::fcntl(d, F_SETFL, flags & ~O_NONBLOCK);
Chris@16: #else // defined(__SYMBIAN32__)
Chris@16:       ioctl_arg_type arg = 0;
Chris@16:       ::ioctl(d, FIONBIO, &arg);
Chris@16: #endif // defined(__SYMBIAN32__)
Chris@16:       state &= ~non_blocking;
Chris@16: 
Chris@16:       errno = 0;
Chris@16:       result = error_wrapper(::close(d), ec);
Chris@16:     }
Chris@16:   }
Chris@16: 
Chris@16:   if (result == 0)
Chris@16:     ec = boost::system::error_code();
Chris@16:   return result;
Chris@16: }
Chris@16: 
Chris@16: bool set_user_non_blocking(int d, state_type& state,
Chris@16:     bool value, boost::system::error_code& ec)
Chris@16: {
Chris@16:   if (d == -1)
Chris@16:   {
Chris@16:     ec = boost::asio::error::bad_descriptor;
Chris@16:     return false;
Chris@16:   }
Chris@16: 
Chris@16:   errno = 0;
Chris@16: #if defined(__SYMBIAN32__)
Chris@16:   int result = error_wrapper(::fcntl(d, F_GETFL, 0), ec);
Chris@16:   if (result >= 0)
Chris@16:   {
Chris@16:     errno = 0;
Chris@16:     int flag = (value ? (result | O_NONBLOCK) : (result & ~O_NONBLOCK));
Chris@16:     result = error_wrapper(::fcntl(d, F_SETFL, flag), ec);
Chris@16:   }
Chris@16: #else // defined(__SYMBIAN32__)
Chris@16:   ioctl_arg_type arg = (value ? 1 : 0);
Chris@16:   int result = error_wrapper(::ioctl(d, FIONBIO, &arg), ec);
Chris@16: #endif // defined(__SYMBIAN32__)
Chris@16: 
Chris@16:   if (result >= 0)
Chris@16:   {
Chris@16:     ec = boost::system::error_code();
Chris@16:     if (value)
Chris@16:       state |= user_set_non_blocking;
Chris@16:     else
Chris@16:     {
Chris@16:       // Clearing the user-set non-blocking mode always overrides any
Chris@16:       // internally-set non-blocking flag. Any subsequent asynchronous
Chris@16:       // operations will need to re-enable non-blocking I/O.
Chris@16:       state &= ~(user_set_non_blocking | internal_non_blocking);
Chris@16:     }
Chris@16:     return true;
Chris@16:   }
Chris@16: 
Chris@16:   return false;
Chris@16: }
Chris@16: 
Chris@16: bool set_internal_non_blocking(int d, state_type& state,
Chris@16:     bool value, boost::system::error_code& ec)
Chris@16: {
Chris@16:   if (d == -1)
Chris@16:   {
Chris@16:     ec = boost::asio::error::bad_descriptor;
Chris@16:     return false;
Chris@16:   }
Chris@16: 
Chris@16:   if (!value && (state & user_set_non_blocking))
Chris@16:   {
Chris@16:     // It does not make sense to clear the internal non-blocking flag if the
Chris@16:     // user still wants non-blocking behaviour. Return an error and let the
Chris@16:     // caller figure out whether to update the user-set non-blocking flag.
Chris@16:     ec = boost::asio::error::invalid_argument;
Chris@16:     return false;
Chris@16:   }
Chris@16: 
Chris@16:   errno = 0;
Chris@16: #if defined(__SYMBIAN32__)
Chris@16:   int result = error_wrapper(::fcntl(d, F_GETFL, 0), ec);
Chris@16:   if (result >= 0)
Chris@16:   {
Chris@16:     errno = 0;
Chris@16:     int flag = (value ? (result | O_NONBLOCK) : (result & ~O_NONBLOCK));
Chris@16:     result = error_wrapper(::fcntl(d, F_SETFL, flag), ec);
Chris@16:   }
Chris@16: #else // defined(__SYMBIAN32__)
Chris@16:   ioctl_arg_type arg = (value ? 1 : 0);
Chris@16:   int result = error_wrapper(::ioctl(d, FIONBIO, &arg), ec);
Chris@16: #endif // defined(__SYMBIAN32__)
Chris@16: 
Chris@16:   if (result >= 0)
Chris@16:   {
Chris@16:     ec = boost::system::error_code();
Chris@16:     if (value)
Chris@16:       state |= internal_non_blocking;
Chris@16:     else
Chris@16:       state &= ~internal_non_blocking;
Chris@16:     return true;
Chris@16:   }
Chris@16: 
Chris@16:   return false;
Chris@16: }
Chris@16: 
Chris@16: std::size_t sync_read(int d, state_type state, buf* bufs,
Chris@16:     std::size_t count, bool all_empty, boost::system::error_code& ec)
Chris@16: {
Chris@16:   if (d == -1)
Chris@16:   {
Chris@16:     ec = boost::asio::error::bad_descriptor;
Chris@16:     return 0;
Chris@16:   }
Chris@16: 
Chris@16:   // A request to read 0 bytes on a stream is a no-op.
Chris@16:   if (all_empty)
Chris@16:   {
Chris@16:     ec = boost::system::error_code();
Chris@16:     return 0;
Chris@16:   }
Chris@16: 
Chris@16:   // Read some data.
Chris@16:   for (;;)
Chris@16:   {
Chris@16:     // Try to complete the operation without blocking.
Chris@16:     errno = 0;
Chris@16:     signed_size_type bytes = error_wrapper(::readv(
Chris@16:           d, bufs, static_cast<int>(count)), ec);
Chris@16: 
Chris@16:     // Check if operation succeeded.
Chris@16:     if (bytes > 0)
Chris@16:       return bytes;
Chris@16: 
Chris@16:     // Check for EOF.
Chris@16:     if (bytes == 0)
Chris@16:     {
Chris@16:       ec = boost::asio::error::eof;
Chris@16:       return 0;
Chris@16:     }
Chris@16: 
Chris@16:     // Operation failed.
Chris@16:     if ((state & user_set_non_blocking)
Chris@16:         || (ec != boost::asio::error::would_block
Chris@16:           && ec != boost::asio::error::try_again))
Chris@16:       return 0;
Chris@16: 
Chris@16:     // Wait for descriptor to become ready.
Chris@16:     if (descriptor_ops::poll_read(d, 0, ec) < 0)
Chris@16:       return 0;
Chris@16:   }
Chris@16: }
Chris@16: 
Chris@16: bool non_blocking_read(int d, buf* bufs, std::size_t count,
Chris@16:     boost::system::error_code& ec, std::size_t& bytes_transferred)
Chris@16: {
Chris@16:   for (;;)
Chris@16:   {
Chris@16:     // Read some data.
Chris@16:     errno = 0;
Chris@16:     signed_size_type bytes = error_wrapper(::readv(
Chris@16:           d, bufs, static_cast<int>(count)), ec);
Chris@16: 
Chris@16:     // Check for end of stream.
Chris@16:     if (bytes == 0)
Chris@16:     {
Chris@16:       ec = boost::asio::error::eof;
Chris@16:       return true;
Chris@16:     }
Chris@16: 
Chris@16:     // Retry operation if interrupted by signal.
Chris@16:     if (ec == boost::asio::error::interrupted)
Chris@16:       continue;
Chris@16: 
Chris@16:     // Check if we need to run the operation again.
Chris@16:     if (ec == boost::asio::error::would_block
Chris@16:         || ec == boost::asio::error::try_again)
Chris@16:       return false;
Chris@16: 
Chris@16:     // Operation is complete.
Chris@16:     if (bytes > 0)
Chris@16:     {
Chris@16:       ec = boost::system::error_code();
Chris@16:       bytes_transferred = bytes;
Chris@16:     }
Chris@16:     else
Chris@16:       bytes_transferred = 0;
Chris@16: 
Chris@16:     return true;
Chris@16:   }
Chris@16: }
Chris@16: 
Chris@16: std::size_t sync_write(int d, state_type state, const buf* bufs,
Chris@16:     std::size_t count, bool all_empty, boost::system::error_code& ec)
Chris@16: {
Chris@16:   if (d == -1)
Chris@16:   {
Chris@16:     ec = boost::asio::error::bad_descriptor;
Chris@16:     return 0;
Chris@16:   }
Chris@16: 
Chris@16:   // A request to write 0 bytes on a stream is a no-op.
Chris@16:   if (all_empty)
Chris@16:   {
Chris@16:     ec = boost::system::error_code();
Chris@16:     return 0;
Chris@16:   }
Chris@16: 
Chris@16:   // Write some data.
Chris@16:   for (;;)
Chris@16:   {
Chris@16:     // Try to complete the operation without blocking.
Chris@16:     errno = 0;
Chris@16:     signed_size_type bytes = error_wrapper(::writev(
Chris@16:           d, bufs, static_cast<int>(count)), ec);
Chris@16: 
Chris@16:     // Check if operation succeeded.
Chris@16:     if (bytes > 0)
Chris@16:       return bytes;
Chris@16: 
Chris@16:     // Operation failed.
Chris@16:     if ((state & user_set_non_blocking)
Chris@16:         || (ec != boost::asio::error::would_block
Chris@16:           && ec != boost::asio::error::try_again))
Chris@16:       return 0;
Chris@16: 
Chris@16:     // Wait for descriptor to become ready.
Chris@16:     if (descriptor_ops::poll_write(d, 0, ec) < 0)
Chris@16:       return 0;
Chris@16:   }
Chris@16: }
Chris@16: 
Chris@16: bool non_blocking_write(int d, const buf* bufs, std::size_t count,
Chris@16:     boost::system::error_code& ec, std::size_t& bytes_transferred)
Chris@16: {
Chris@16:   for (;;)
Chris@16:   {
Chris@16:     // Write some data.
Chris@16:     errno = 0;
Chris@16:     signed_size_type bytes = error_wrapper(::writev(
Chris@16:           d, bufs, static_cast<int>(count)), ec);
Chris@16: 
Chris@16:     // Retry operation if interrupted by signal.
Chris@16:     if (ec == boost::asio::error::interrupted)
Chris@16:       continue;
Chris@16: 
Chris@16:     // Check if we need to run the operation again.
Chris@16:     if (ec == boost::asio::error::would_block
Chris@16:         || ec == boost::asio::error::try_again)
Chris@16:       return false;
Chris@16: 
Chris@16:     // Operation is complete.
Chris@16:     if (bytes >= 0)
Chris@16:     {
Chris@16:       ec = boost::system::error_code();
Chris@16:       bytes_transferred = bytes;
Chris@16:     }
Chris@16:     else
Chris@16:       bytes_transferred = 0;
Chris@16: 
Chris@16:     return true;
Chris@16:   }
Chris@16: }
Chris@16: 
Chris@16: int ioctl(int d, state_type& state, long cmd,
Chris@16:     ioctl_arg_type* arg, boost::system::error_code& ec)
Chris@16: {
Chris@16:   if (d == -1)
Chris@16:   {
Chris@16:     ec = boost::asio::error::bad_descriptor;
Chris@16:     return -1;
Chris@16:   }
Chris@16: 
Chris@16:   errno = 0;
Chris@16:   int result = error_wrapper(::ioctl(d, cmd, arg), ec);
Chris@16: 
Chris@16:   if (result >= 0)
Chris@16:   {
Chris@16:     ec = boost::system::error_code();
Chris@16: 
Chris@16:     // When updating the non-blocking mode we always perform the ioctl syscall,
Chris@16:     // even if the flags would otherwise indicate that the descriptor is
Chris@16:     // already in the correct state. This ensures that the underlying
Chris@16:     // descriptor is put into the state that has been requested by the user. If
Chris@16:     // the ioctl syscall was successful then we need to update the flags to
Chris@16:     // match.
Chris@16:     if (cmd == static_cast<long>(FIONBIO))
Chris@16:     {
Chris@16:       if (*arg)
Chris@16:       {
Chris@16:         state |= user_set_non_blocking;
Chris@16:       }
Chris@16:       else
Chris@16:       {
Chris@16:         // Clearing the non-blocking mode always overrides any internally-set
Chris@16:         // non-blocking flag. Any subsequent asynchronous operations will need
Chris@16:         // to re-enable non-blocking I/O.
Chris@16:         state &= ~(user_set_non_blocking | internal_non_blocking);
Chris@16:       }
Chris@16:     }
Chris@16:   }
Chris@16: 
Chris@16:   return result;
Chris@16: }
Chris@16: 
Chris@16: int fcntl(int d, int cmd, boost::system::error_code& ec)
Chris@16: {
Chris@16:   if (d == -1)
Chris@16:   {
Chris@16:     ec = boost::asio::error::bad_descriptor;
Chris@16:     return -1;
Chris@16:   }
Chris@16: 
Chris@16:   errno = 0;
Chris@16:   int result = error_wrapper(::fcntl(d, cmd), ec);
Chris@16:   if (result != -1)
Chris@16:     ec = boost::system::error_code();
Chris@16:   return result;
Chris@16: }
Chris@16: 
Chris@16: int fcntl(int d, int cmd, long arg, boost::system::error_code& ec)
Chris@16: {
Chris@16:   if (d == -1)
Chris@16:   {
Chris@16:     ec = boost::asio::error::bad_descriptor;
Chris@16:     return -1;
Chris@16:   }
Chris@16: 
Chris@16:   errno = 0;
Chris@16:   int result = error_wrapper(::fcntl(d, cmd, arg), ec);
Chris@16:   if (result != -1)
Chris@16:     ec = boost::system::error_code();
Chris@16:   return result;
Chris@16: }
Chris@16: 
Chris@16: int poll_read(int d, state_type state, boost::system::error_code& ec)
Chris@16: {
Chris@16:   if (d == -1)
Chris@16:   {
Chris@16:     ec = boost::asio::error::bad_descriptor;
Chris@16:     return -1;
Chris@16:   }
Chris@16: 
Chris@16:   pollfd fds;
Chris@16:   fds.fd = d;
Chris@16:   fds.events = POLLIN;
Chris@16:   fds.revents = 0;
Chris@16:   int timeout = (state & user_set_non_blocking) ? 0 : -1;
Chris@16:   errno = 0;
Chris@16:   int result = error_wrapper(::poll(&fds, 1, timeout), ec);
Chris@16:   if (result == 0)
Chris@16:     ec = (state & user_set_non_blocking)
Chris@16:       ? boost::asio::error::would_block : boost::system::error_code();
Chris@16:   else if (result > 0)
Chris@16:     ec = boost::system::error_code();
Chris@16:   return result;
Chris@16: }
Chris@16: 
Chris@16: int poll_write(int d, state_type state, boost::system::error_code& ec)
Chris@16: {
Chris@16:   if (d == -1)
Chris@16:   {
Chris@16:     ec = boost::asio::error::bad_descriptor;
Chris@16:     return -1;
Chris@16:   }
Chris@16: 
Chris@16:   pollfd fds;
Chris@16:   fds.fd = d;
Chris@16:   fds.events = POLLOUT;
Chris@16:   fds.revents = 0;
Chris@16:   int timeout = (state & user_set_non_blocking) ? 0 : -1;
Chris@16:   errno = 0;
Chris@16:   int result = error_wrapper(::poll(&fds, 1, timeout), ec);
Chris@16:   if (result == 0)
Chris@16:     ec = (state & user_set_non_blocking)
Chris@16:       ? boost::asio::error::would_block : boost::system::error_code();
Chris@16:   else if (result > 0)
Chris@16:     ec = boost::system::error_code();
Chris@16:   return result;
Chris@16: }
Chris@16: 
Chris@16: } // namespace descriptor_ops
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_WINDOWS)
Chris@16:        //   && !defined(BOOST_ASIO_WINDOWS_RUNTIME)
Chris@16:        //   && !defined(__CYGWIN__)
Chris@16: 
Chris@16: #endif // BOOST_ASIO_DETAIL_IMPL_DESCRIPTOR_OPS_IPP