// // socket_select_interrupter.hpp // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ // // Copyright (c) 2003-2010 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_SOCKET_SELECT_INTERRUPTER_HPP #define BOOST_ASIO_DETAIL_SOCKET_SELECT_INTERRUPTER_HPP #if defined(_MSC_VER) && (_MSC_VER >= 1200) # pragma once #endif // defined(_MSC_VER) && (_MSC_VER >= 1200) #include #include #include #include #include #include #include #include #include #include namespace boost { namespace asio { namespace detail { class socket_select_interrupter { public: // Constructor. socket_select_interrupter() { boost::system::error_code ec; socket_holder acceptor(socket_ops::socket( AF_INET, SOCK_STREAM, IPPROTO_TCP, ec)); if (acceptor.get() == invalid_socket) { boost::system::system_error e(ec, "socket_select_interrupter"); boost::throw_exception(e); } int opt = 1; socket_ops::setsockopt(acceptor.get(), SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt), ec); using namespace std; // For memset. sockaddr_in4_type addr; std::size_t addr_len = sizeof(addr); memset(&addr, 0, sizeof(addr)); addr.sin_family = AF_INET; addr.sin_addr.s_addr = inet_addr("127.0.0.1"); addr.sin_port = 0; if (socket_ops::bind(acceptor.get(), (const socket_addr_type*)&addr, addr_len, ec) == socket_error_retval) { boost::system::system_error e(ec, "socket_select_interrupter"); boost::throw_exception(e); } if (socket_ops::getsockname(acceptor.get(), (socket_addr_type*)&addr, &addr_len, ec) == socket_error_retval) { boost::system::system_error e(ec, "socket_select_interrupter"); boost::throw_exception(e); } // Some broken firewalls on Windows will intermittently cause getsockname to // return 0.0.0.0 when the socket is actually bound to 127.0.0.1. We // explicitly specify the target address here to work around this problem. addr.sin_addr.s_addr = inet_addr("127.0.0.1"); if (socket_ops::listen(acceptor.get(), SOMAXCONN, ec) == socket_error_retval) { boost::system::system_error e(ec, "socket_select_interrupter"); boost::throw_exception(e); } socket_holder client(socket_ops::socket( AF_INET, SOCK_STREAM, IPPROTO_TCP, ec)); if (client.get() == invalid_socket) { boost::system::system_error e(ec, "socket_select_interrupter"); boost::throw_exception(e); } if (socket_ops::connect(client.get(), (const socket_addr_type*)&addr, addr_len, ec) == socket_error_retval) { boost::system::system_error e(ec, "socket_select_interrupter"); boost::throw_exception(e); } socket_holder server(socket_ops::accept(acceptor.get(), 0, 0, ec)); if (server.get() == invalid_socket) { boost::system::system_error e(ec, "socket_select_interrupter"); boost::throw_exception(e); } ioctl_arg_type non_blocking = 1; if (socket_ops::ioctl(client.get(), FIONBIO, &non_blocking, ec)) { boost::system::system_error e(ec, "socket_select_interrupter"); boost::throw_exception(e); } opt = 1; socket_ops::setsockopt(client.get(), IPPROTO_TCP, TCP_NODELAY, &opt, sizeof(opt), ec); non_blocking = 1; if (socket_ops::ioctl(server.get(), FIONBIO, &non_blocking, ec)) { boost::system::system_error e(ec, "socket_select_interrupter"); boost::throw_exception(e); } opt = 1; socket_ops::setsockopt(server.get(), IPPROTO_TCP, TCP_NODELAY, &opt, sizeof(opt), ec); read_descriptor_ = server.release(); write_descriptor_ = client.release(); } // Destructor. ~socket_select_interrupter() { boost::system::error_code ec; if (read_descriptor_ != invalid_socket) socket_ops::close(read_descriptor_, ec); if (write_descriptor_ != invalid_socket) socket_ops::close(write_descriptor_, ec); } // Interrupt the select call. void interrupt() { char byte = 0; socket_ops::buf b; socket_ops::init_buf(b, &byte, 1); boost::system::error_code ec; socket_ops::send(write_descriptor_, &b, 1, 0, ec); } // Reset the select interrupt. Returns true if the call was interrupted. bool reset() { char data[1024]; socket_ops::buf b; socket_ops::init_buf(b, data, sizeof(data)); boost::system::error_code ec; int bytes_read = socket_ops::recv(read_descriptor_, &b, 1, 0, ec); bool was_interrupted = (bytes_read > 0); while (bytes_read == sizeof(data)) bytes_read = socket_ops::recv(read_descriptor_, &b, 1, 0, ec); return was_interrupted; } // Get the read descriptor to be passed to select. socket_type read_descriptor() const { return read_descriptor_; } private: // The read end of a connection used to interrupt the select call. This file // descriptor is passed to select such that when it is time to stop, a single // byte will be written on the other end of the connection and this // descriptor will become readable. socket_type read_descriptor_; // The write end of a connection used to interrupt the select call. A single // byte may be written to this to wake up the select which is waiting for the // other end to become readable. socket_type write_descriptor_; }; } // namespace detail } // namespace asio } // namespace boost #include #endif // BOOST_ASIO_DETAIL_SOCKET_SELECT_INTERRUPTER_HPP