/usr/include/boost/asio/detail/impl/descriptor_ops.ipp is in libboost1.49-dev 1.49.0-3.2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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// detail/impl/descriptor_ops.ipp
// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
//
// Copyright (c) 2003-2012 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_WINDOWS) && !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;
int 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;
int 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;
int 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;
int 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, long 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, long 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;
}
} // namespace descriptor_ops
} // namespace detail
} // namespace asio
} // namespace boost
#include <boost/asio/detail/pop_options.hpp>
#endif // !defined(BOOST_WINDOWS) && !defined(__CYGWIN__)
#endif // BOOST_ASIO_DETAIL_IMPL_DESCRIPTOR_OPS_IPP
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