/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.apache.sshd.server.x11;
import java.io.IOException;
import java.net.BindException;
import java.net.InetSocketAddress;
import org.apache.sshd.client.channel.AbstractClientChannel;
import org.apache.sshd.client.future.DefaultOpenFuture;
import org.apache.sshd.client.future.OpenFuture;
import org.apache.sshd.common.SshConstants;
import org.apache.sshd.common.SshException;
import org.apache.sshd.common.channel.ChannelOutputStream;
import org.apache.sshd.common.future.CloseFuture;
import org.apache.sshd.common.future.DefaultCloseFuture;
import org.apache.sshd.common.future.SshFutureListener;
import org.apache.sshd.common.io.IoAcceptor;
import org.apache.sshd.common.io.IoCloseFuture;
import org.apache.sshd.common.io.IoHandler;
import org.apache.sshd.common.io.IoSession;
import org.apache.sshd.common.util.Buffer;
import org.apache.sshd.common.util.Readable;
import org.apache.sshd.server.session.ServerSession;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* @author <a href="mailto:dev@mina.apache.org">Apache MINA SSHD Project</a>
*/
public class X11ForwardSupport implements IoHandler {
private static String xauthCommand = System.getProperty("sshd.xauthCommand", "xauth");
public static final int X11_DISPLAY_OFFSET = 10;
public static final int MAX_DISPLAYS = 1000;
/**
* Key for the user DISPLAY variable
*/
public static final String ENV_DISPLAY = "DISPLAY";
protected final Logger log = LoggerFactory.getLogger(getClass());
private final ServerSession session;
private IoAcceptor acceptor;
public X11ForwardSupport(ServerSession session) {
super();
this.session = session;
}
public synchronized void initialize() {
if (this.acceptor == null) {
this.acceptor = session.getFactoryManager().getIoServiceFactory()
.createAcceptor(session.getFactoryManager(), this);
}
}
public synchronized void close() {
if (acceptor != null) {
acceptor.dispose();
acceptor = null;
}
}
public synchronized String createDisplay(boolean singleConnection,
String authenticationProtocol, String authenticationCookie,
int screen) throws IOException {
initialize();
int displayNumber, port;
InetSocketAddress addr = null;
for (displayNumber = X11_DISPLAY_OFFSET; displayNumber < MAX_DISPLAYS; displayNumber++) {
port = 6000 + displayNumber;
try {
addr = new InetSocketAddress("127.0.0.1", port);
acceptor.bind(addr);
break;
} catch (BindException bindErr) {
// try until bind succesful or max is reached
}
}
if (displayNumber >= MAX_DISPLAYS) {
log.error("Failed to allocate internet-domain X11 display socket.");
if (acceptor.getBoundAddresses().isEmpty()) {
close();
}
return null;
}
// only support non windows systems
String os = System.getProperty("os.name").toLowerCase();
if (os.indexOf("windows") < 0) {
try {
String authDisplay = "unix:" + displayNumber + "." + screen;
Process p = new ProcessBuilder(xauthCommand, "remove", authDisplay).start();
int result = p.waitFor();
if (result == 0) {
p = new ProcessBuilder(xauthCommand, "add", authDisplay, authenticationProtocol, authenticationCookie).start();
result = p.waitFor();
}
} catch (Exception e) {
log.error("Could not run xauth", e);
return null;
}
return "localhost:" + displayNumber + "." + screen;
} else {
return null;
}
}
public void sessionCreated(IoSession session) throws Exception {
ChannelForwardedX11 channel = new ChannelForwardedX11(session);
session.setAttribute(ChannelForwardedX11.class, channel);
this.session.registerChannel(channel);
OpenFuture future = channel.open().await();
Throwable t = future.getException();
if (t instanceof Exception) {
throw (Exception) t;
} else if (t != null) {
throw new Exception(t);
}
}
public void sessionClosed(IoSession session) throws Exception {
ChannelForwardedX11 channel = (ChannelForwardedX11) session.getAttribute(ChannelForwardedX11.class);
if ( channel != null ){
channel.close(false);
}
}
public void messageReceived(IoSession session, Readable message) throws Exception {
ChannelForwardedX11 channel = (ChannelForwardedX11) session.getAttribute(ChannelForwardedX11.class);
Buffer buffer = new Buffer();
buffer.putBuffer(message);
channel.getOut().write(buffer.array(), buffer.rpos(), buffer.available());
channel.getOut().flush();
}
public void exceptionCaught(IoSession session, Throwable cause) throws Exception {
cause.printStackTrace();
session.close(false);
}
public static class ChannelForwardedX11 extends AbstractClientChannel {
private final IoSession serverSession;
public ChannelForwardedX11(IoSession serverSession) {
super("x11");
this.serverSession = serverSession;
}
public synchronized OpenFuture open() throws IOException {
InetSocketAddress remote = (InetSocketAddress) serverSession.getRemoteAddress();
if (closeFuture.isClosed()) {
throw new SshException("Session has been closed");
}
openFuture = new DefaultOpenFuture(lock);
log.info("Send SSH_MSG_CHANNEL_OPEN on channel {}", id);
Buffer buffer = session.createBuffer(SshConstants.Message.SSH_MSG_CHANNEL_OPEN, 0);
buffer.putString(type);
buffer.putInt(id);
buffer.putInt(localWindow.getSize());
buffer.putInt(localWindow.getPacketSize());
buffer.putString(remote.getAddress().getHostAddress());
buffer.putInt(remote.getPort());
writePacket(buffer);
return openFuture;
}
@Override
protected synchronized void doOpen() throws IOException {
out = new ChannelOutputStream(this, remoteWindow, log, SshConstants.Message.SSH_MSG_CHANNEL_DATA);
}
@Override
protected synchronized CloseFuture preClose(boolean immediately) {
final CloseFuture future = new DefaultCloseFuture(null);
serverSession.close(immediately).addListener(new SshFutureListener<IoCloseFuture>() {
public void operationComplete(IoCloseFuture f) {
future.setClosed();
}
});
return future;
}
protected synchronized void doWriteData(byte[] data, int off, int len) throws IOException {
localWindow.consumeAndCheck(len);
serverSession.write(new Buffer(data, off, len));
}
@Override
public void handleEof() throws IOException {
super.handleEof();
serverSession.close(false);
}
}
}