libevent/evutil.c

/*
 * Copyright (c) 2007 Niels Provos <provos@citi.umich.edu>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#ifdef WIN32
#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#undef WIN32_LEAN_AND_MEAN
#include <winsock2.h>
#include "misc.h"
#endif

#include <sys/types.h>
#ifdef HAVE_SYS_SOCKET_H
#include <sys/socket.h>
#endif
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#ifdef HAVE_FCNTL_H
#include <fcntl.h>
#endif
#include <errno.h>

#include "evutil.h"
#include "log.h"

int
evutil_socketpair(int family, int type, int protocol, evutil_socket_t fd[2])
{
#ifndef WIN32
	return socketpair(family, type, protocol, fd);
#else
	/* This code is originally from Tor.  Used with permission. */

	/* This socketpair does not work when localhost is down. So
	 * it's really not the same thing at all. But it's close enough
	 * for now, and really, when localhost is down sometimes, we
	 * have other problems too.
	 */
	evutil_socket_t listener = -1;
	evutil_socket_t connector = -1;
	evutil_socket_t acceptor = -1;
	struct sockaddr_in listen_addr;
	struct sockaddr_in connect_addr;
	int size;
	int saved_errno = -1;

	if (protocol
#ifdef AF_UNIX
		|| family != AF_UNIX
#endif
		) {
		EVUTIL_SET_SOCKET_ERROR(WSAEAFNOSUPPORT);
		return -1;
	}
	if (!fd) {
		EVUTIL_SET_SOCKET_ERROR(WSAEINVAL);
		return -1;
	}

	listener = socket(AF_INET, type, 0);
	if (listener < 0)
		return -1;
	memset(&listen_addr, 0, sizeof(listen_addr));
	listen_addr.sin_family = AF_INET;
	listen_addr.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
	listen_addr.sin_port = 0;	/* kernel chooses port.	 */
	if (bind(listener, (struct sockaddr *) &listen_addr, sizeof (listen_addr))
		== -1)
		goto tidy_up_and_fail;
	if (listen(listener, 1) == -1)
		goto tidy_up_and_fail;

	connector = socket(AF_INET, type, 0);
	if (connector < 0)
		goto tidy_up_and_fail;
	/* We want to find out the port number to connect to.  */
	size = sizeof(connect_addr);
	if (getsockname(listener, (struct sockaddr *) &connect_addr, &size) == -1)
		goto tidy_up_and_fail;
	if (size != sizeof (connect_addr))
		goto abort_tidy_up_and_fail;
	if (connect(connector, (struct sockaddr *) &connect_addr,
				sizeof(connect_addr)) == -1)
		goto tidy_up_and_fail;

	size = sizeof(listen_addr);
	acceptor = accept(listener, (struct sockaddr *) &listen_addr, &size);
	if (acceptor < 0)
		goto tidy_up_and_fail;
	if (size != sizeof(listen_addr))
		goto abort_tidy_up_and_fail;
	EVUTIL_CLOSESOCKET(listener);
	/* Now check we are talking to ourself by matching port and host on the
	   two sockets.	 */
	if (getsockname(connector, (struct sockaddr *) &connect_addr, &size) == -1)
		goto tidy_up_and_fail;
	if (size != sizeof (connect_addr)
		|| listen_addr.sin_family != connect_addr.sin_family
		|| listen_addr.sin_addr.s_addr != connect_addr.sin_addr.s_addr
		|| listen_addr.sin_port != connect_addr.sin_port)
		goto abort_tidy_up_and_fail;
	fd[0] = connector;
	fd[1] = acceptor;

	return 0;

 abort_tidy_up_and_fail:
	saved_errno = WSAECONNABORTED;
 tidy_up_and_fail:
	if (saved_errno < 0)
		saved_errno = WSAGetLastError();
	if (listener != -1)
		EVUTIL_CLOSESOCKET(listener);
	if (connector != -1)
		EVUTIL_CLOSESOCKET(connector);
	if (acceptor != -1)
		EVUTIL_CLOSESOCKET(acceptor);

	EVUTIL_SET_SOCKET_ERROR(saved_errno);
	return -1;
#endif
}

int
evutil_make_socket_nonblocking(evutil_socket_t fd)
{
#ifdef WIN32
	{
		unsigned long nonblocking = 1;
		ioctlsocket(fd, FIONBIO, (unsigned long*) &nonblocking);
	}
#else
	if (fcntl(fd, F_SETFL, O_NONBLOCK) == -1) {
		event_warn("fcntl(O_NONBLOCK)");
		return -1;
}	
#endif
	return 0;
}