/*
* 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.Closeable;
import org.apache.sshd.common.SshConstants;
import org.apache.sshd.common.SshException;
import org.apache.sshd.common.channel.ChannelOutputStream;
import org.apache.sshd.common.io.IoAcceptor;
import org.apache.sshd.common.io.IoHandler;
import org.apache.sshd.common.io.IoSession;
import org.apache.sshd.common.session.ConnectionService;
import org.apache.sshd.common.util.Buffer;
import org.apache.sshd.common.util.CloseableUtils;
import org.apache.sshd.common.util.Readable;
/**
* @author <a href="mailto:dev@mina.apache.org">Apache MINA SSHD Project</a>
*/
public class X11ForwardSupport
extends CloseableUtils.
AbstractInnerCloseable implements IoHandler,
Closeable {
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";
private final ConnectionService service
;
private IoAcceptor acceptor
;
public X11ForwardSupport
(ConnectionService service
) {
super();
this.
service = service
;
}
public void close
() {
close
(true);
}
@
Override
protected Closeable getInnerCloseable
() {
return builder
().
close(acceptor
).
build();
}
public synchronized String createDisplay
(boolean singleConnection,
String authenticationProtocol,
String authenticationCookie,
int screen
) throws IOException {
if (isClosed
()) {
throw new IllegalStateException("X11ForwardSupport is closed");
}
if (isClosing
()) {
throw new IllegalStateException("X11ForwardSupport is closing");
}
if (acceptor ==
null) {
acceptor = service.
getSession().
getFactoryManager().
getIoServiceFactory().
createAcceptor(this);
}
int displayNumber, port
;
InetSocketAddress addr
;
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.
contains("windows")) {
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.
service.
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.
getInvertedIn().
write(buffer.
array(), buffer.
rpos(), buffer.
available());
channel.
getInvertedIn().
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.
SSH_MSG_CHANNEL_OPEN);
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 {
if (streaming == Streaming.
Async) {
throw new IllegalArgumentException("Asynchronous streaming isn't supported yet on this channel");
}
invertedIn = out =
new ChannelOutputStream
(this, remoteWindow, log, SshConstants.
SSH_MSG_CHANNEL_DATA);
}
@
Override
protected Closeable getInnerCloseable
() {
return builder
().
sequential(serverSession,
super.
getInnerCloseable()).
build();
}
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);
}
}
}