boost/asio/detail/impl/descriptor_ops.ipp
// // detail/impl/descriptor_ops.ipp // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ // // Copyright (c) 2003-2023 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) { int result = ::open(path, flags); get_last_error(ec, result < 0); return result; } int open(const char* path, int flags, unsigned mode, boost::system::error_code& ec) { int result = ::open(path, flags, mode); get_last_error(ec, result < 0); return result; } int close(int d, state_type& state, boost::system::error_code& ec) { int result = 0; if (d != -1) { result = ::close(d); get_last_error(ec, result < 0); 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__) || defined(__EMSCRIPTEN__) int flags = ::fcntl(d, F_GETFL, 0); if (flags >= 0) ::fcntl(d, F_SETFL, flags & ~O_NONBLOCK); #else // defined(__SYMBIAN32__) || defined(__EMSCRIPTEN__) ioctl_arg_type arg = 0; # if defined(ENOTTY) result = ::ioctl(d, FIONBIO, &arg); get_last_error(ec, result < 0); if (ec.value() == ENOTTY) { int flags = ::fcntl(d, F_GETFL, 0); if (flags >= 0) ::fcntl(d, F_SETFL, flags & ~O_NONBLOCK); } # else // defined(ENOTTY) ::ioctl(d, FIONBIO, &arg); # endif // defined(ENOTTY) #endif // defined(__SYMBIAN32__) || defined(__EMSCRIPTEN__) state &= ~non_blocking; result = ::close(d); get_last_error(ec, result < 0); } } 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; } #if defined(__SYMBIAN32__) || defined(__EMSCRIPTEN__) int result = ::fcntl(d, F_GETFL, 0); get_last_error(ec, result < 0); if (result >= 0) { int flag = (value ? (result | O_NONBLOCK) : (result & ~O_NONBLOCK)); result = ::fcntl(d, F_SETFL, flag); get_last_error(ec, result < 0); } #else // defined(__SYMBIAN32__) || defined(__EMSCRIPTEN__) ioctl_arg_type arg = (value ? 1 : 0); int result = ::ioctl(d, FIONBIO, &arg); get_last_error(ec, result < 0); # if defined(ENOTTY) if (ec.value() == ENOTTY) { result = ::fcntl(d, F_GETFL, 0); get_last_error(ec, result < 0); if (result >= 0) { int flag = (value ? (result | O_NONBLOCK) : (result & ~O_NONBLOCK)); result = ::fcntl(d, F_SETFL, flag); get_last_error(ec, result < 0); } } # endif // defined(ENOTTY) #endif // defined(__SYMBIAN32__) || defined(__EMSCRIPTEN__) if (result >= 0) { 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; } #if defined(__SYMBIAN32__) || defined(__EMSCRIPTEN__) int result = ::fcntl(d, F_GETFL, 0); get_last_error(ec, result < 0); if (result >= 0) { int flag = (value ? (result | O_NONBLOCK) : (result & ~O_NONBLOCK)); result = ::fcntl(d, F_SETFL, flag); get_last_error(ec, result < 0); } #else // defined(__SYMBIAN32__) || defined(__EMSCRIPTEN__) ioctl_arg_type arg = (value ? 1 : 0); int result = ::ioctl(d, FIONBIO, &arg); get_last_error(ec, result < 0); # if defined(ENOTTY) if (ec.value() == ENOTTY) { result = ::fcntl(d, F_GETFL, 0); get_last_error(ec, result < 0); if (result >= 0) { int flag = (value ? (result | O_NONBLOCK) : (result & ~O_NONBLOCK)); result = ::fcntl(d, F_SETFL, flag); get_last_error(ec, result < 0); } } # endif // defined(ENOTTY) #endif // defined(__SYMBIAN32__) || defined(__EMSCRIPTEN__) if (result >= 0) { 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) { boost::asio::error::clear(ec); return 0; } // Read some data. for (;;) { // Try to complete the operation without blocking. signed_size_type bytes = ::readv(d, bufs, static_cast<int>(count)); get_last_error(ec, bytes < 0); // 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; } } std::size_t sync_read1(int d, state_type state, void* data, std::size_t size, 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 (size == 0) { boost::asio::error::clear(ec); return 0; } // Read some data. for (;;) { // Try to complete the operation without blocking. signed_size_type bytes = ::read(d, data, size); get_last_error(ec, bytes < 0); // 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. signed_size_type bytes = ::readv(d, bufs, static_cast<int>(count)); get_last_error(ec, bytes < 0); // Check for end of stream. if (bytes == 0) { ec = boost::asio::error::eof; return true; } // Check if operation succeeded. if (bytes > 0) { bytes_transferred = bytes; 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 failed. bytes_transferred = 0; return true; } } bool non_blocking_read1(int d, void* data, std::size_t size, boost::system::error_code& ec, std::size_t& bytes_transferred) { for (;;) { // Read some data. signed_size_type bytes = ::read(d, data, size); get_last_error(ec, bytes < 0); // Check for end of stream. if (bytes == 0) { ec = boost::asio::error::eof; return true; } // Check if operation succeeded. if (bytes > 0) { bytes_transferred = bytes; 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 failed. 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) { boost::asio::error::clear(ec); return 0; } // Write some data. for (;;) { // Try to complete the operation without blocking. signed_size_type bytes = ::writev(d, bufs, static_cast<int>(count)); get_last_error(ec, bytes < 0); // 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; } } std::size_t sync_write1(int d, state_type state, const void* data, std::size_t size, 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 (size == 0) { boost::asio::error::clear(ec); return 0; } // Write some data. for (;;) { // Try to complete the operation without blocking. signed_size_type bytes = ::write(d, data, size); get_last_error(ec, bytes < 0); // 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. signed_size_type bytes = ::writev(d, bufs, static_cast<int>(count)); get_last_error(ec, bytes < 0); // Check if operation succeeded. if (bytes >= 0) { bytes_transferred = bytes; 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 failed. bytes_transferred = 0; return true; } } bool non_blocking_write1(int d, const void* data, std::size_t size, boost::system::error_code& ec, std::size_t& bytes_transferred) { for (;;) { // Write some data. signed_size_type bytes = ::write(d, data, size); get_last_error(ec, bytes < 0); // Check if operation succeeded. if (bytes >= 0) { bytes_transferred = bytes; 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 failed. bytes_transferred = 0; return true; } } #if defined(BOOST_ASIO_HAS_FILE) std::size_t sync_read_at(int d, state_type state, uint64_t offset, 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) { boost::asio::error::clear(ec); return 0; } // Read some data. for (;;) { // Try to complete the operation without blocking. signed_size_type bytes = ::preadv(d, bufs, static_cast<int>(count), offset); get_last_error(ec, bytes < 0); // 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; } } std::size_t sync_read_at1(int d, state_type state, uint64_t offset, void* data, std::size_t size, 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 (size == 0) { boost::asio::error::clear(ec); return 0; } // Read some data. for (;;) { // Try to complete the operation without blocking. signed_size_type bytes = ::pread(d, data, size, offset); get_last_error(ec, bytes < 0); // 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_at(int d, uint64_t offset, buf* bufs, std::size_t count, boost::system::error_code& ec, std::size_t& bytes_transferred) { for (;;) { // Read some data. signed_size_type bytes = ::preadv(d, bufs, static_cast<int>(count), offset); get_last_error(ec, bytes < 0); // Check for EOF. if (bytes == 0) { ec = boost::asio::error::eof; return true; } // Check if operation succeeded. if (bytes > 0) { bytes_transferred = bytes; 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 failed. bytes_transferred = 0; return true; } } bool non_blocking_read_at1(int d, uint64_t offset, void* data, std::size_t size, boost::system::error_code& ec, std::size_t& bytes_transferred) { for (;;) { // Read some data. signed_size_type bytes = ::pread(d, data, size, offset); get_last_error(ec, bytes < 0); // Check for EOF. if (bytes == 0) { ec = boost::asio::error::eof; return true; } // Check if operation succeeded. if (bytes > 0) { bytes_transferred = bytes; 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 failed. bytes_transferred = 0; return true; } } std::size_t sync_write_at(int d, state_type state, uint64_t offset, 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) { boost::asio::error::clear(ec); return 0; } // Write some data. for (;;) { // Try to complete the operation without blocking. signed_size_type bytes = ::pwritev(d, bufs, static_cast<int>(count), offset); get_last_error(ec, bytes < 0); // 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; } } std::size_t sync_write_at1(int d, state_type state, uint64_t offset, const void* data, std::size_t size, 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 (size == 0) { boost::asio::error::clear(ec); return 0; } // Write some data. for (;;) { // Try to complete the operation without blocking. signed_size_type bytes = ::pwrite(d, data, size, offset); get_last_error(ec, bytes < 0); // 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_at(int d, uint64_t offset, const buf* bufs, std::size_t count, boost::system::error_code& ec, std::size_t& bytes_transferred) { for (;;) { // Write some data. signed_size_type bytes = ::pwritev(d, bufs, static_cast<int>(count), offset); get_last_error(ec, bytes < 0); // Check if operation succeeded. if (bytes >= 0) { bytes_transferred = bytes; 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 failed. bytes_transferred = 0; return true; } } bool non_blocking_write_at1(int d, uint64_t offset, const void* data, std::size_t size, boost::system::error_code& ec, std::size_t& bytes_transferred) { for (;;) { // Write some data. signed_size_type bytes = ::pwrite(d, data, size, offset); get_last_error(ec, bytes < 0); // Check if operation succeeded. if (bytes >= 0) { bytes_transferred = bytes; 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 failed. bytes_transferred = 0; return true; } } #endif // defined(BOOST_ASIO_HAS_FILE) 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; } int result = ::ioctl(d, cmd, arg); get_last_error(ec, result < 0); if (result >= 0) { // 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; } int result = ::fcntl(d, cmd); get_last_error(ec, result < 0); 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; } int result = ::fcntl(d, cmd, arg); get_last_error(ec, result < 0); 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; int result = ::poll(&fds, 1, timeout); get_last_error(ec, result < 0); if (result == 0) if (state & user_set_non_blocking) ec = boost::asio::error::would_block; 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; int result = ::poll(&fds, 1, timeout); get_last_error(ec, result < 0); if (result == 0) if (state & user_set_non_blocking) ec = boost::asio::error::would_block; 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; int result = ::poll(&fds, 1, timeout); get_last_error(ec, result < 0); if (result == 0) if (state & user_set_non_blocking) ec = boost::asio::error::would_block; 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