/*
* 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.agent.unix;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Collection;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Future;
import org.apache.sshd.agent.SshAgent;
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.channel.ChannelOutputStream;
import org.apache.sshd.common.future.CloseFuture;
import org.apache.sshd.common.util.GenericUtils;
import org.apache.sshd.common.util.ValidateUtils;
import org.apache.sshd.common.util.buffer.Buffer;
import org.apache.sshd.common.util.threads.ThreadUtils;
import org.apache.sshd.server.channel.AbstractServerChannel;
import org.apache.tomcat.jni.Local;
import org.apache.tomcat.jni.Pool;
import org.apache.tomcat.jni.Socket;
import org.apache.tomcat.jni.Status;
/**
* The client side channel that will receive requests forwards by the SSH server.
*/
public class ChannelAgentForwarding extends AbstractServerChannel {
/**
* Property that can be set on the factory manager in order to control
* the buffer size used to forward data from the established channel
*
* @see #MIN_FORWARDER_BUF_SIZE
* @see #MAX_FORWARDER_BUF_SIZE
* @see #DEFAULT_FORWARDER_BUF_SIZE
*/
public static final String FORWARDER_BUFFER_SIZE = "channel-agent-fwd-buf-size";
public static final int MIN_FORWARDER_BUF_SIZE = Byte.MAX_VALUE;
public static final int DEFAULT_FORWARDER_BUF_SIZE = 1024;
public static final int MAX_FORWARDER_BUF_SIZE = Short.MAX_VALUE;
private String authSocket;
private long pool;
private long handle;
private OutputStream out;
private ExecutorService forwardService;
private Future<?> forwarder;
private boolean shutdownForwarder;
public ChannelAgentForwarding() {
super();
}
@Override
protected OpenFuture doInit(Buffer buffer) {
OpenFuture f = new DefaultOpenFuture(this);
try {
out = new ChannelOutputStream(this, getRemoteWindow(), log, SshConstants.SSH_MSG_CHANNEL_DATA, true);
authSocket = this.getString(SshAgent.SSH_AUTHSOCKET_ENV_NAME);
pool = Pool.create(AprLibrary.getInstance().getRootPool());
handle = Local.create(authSocket, pool);
int result = Local.connect(handle, 0);
if (result != Status.APR_SUCCESS) {
throwException(result);
}
ExecutorService service = getExecutorService();
forwardService = (service == null) ? ThreadUtils.newSingleThreadExecutor("ChannelAgentForwarding[" + authSocket + "]") : service;
shutdownForwarder = service != forwardService || isShutdownOnExit();
final int copyBufSize = this.getIntProperty(FORWARDER_BUFFER_SIZE, DEFAULT_FORWARDER_BUF_SIZE);
ValidateUtils.checkTrue(copyBufSize >= MIN_FORWARDER_BUF_SIZE, "Copy buf size below min.: %d", copyBufSize);
ValidateUtils.checkTrue(copyBufSize <= MAX_FORWARDER_BUF_SIZE, "Copy buf size above max.: %d", copyBufSize);
forwarder = forwardService.submit(() -> {
try {
byte[] buf = new byte[copyBufSize];
while (true) {
int len = Socket.recv(handle, buf, 0, buf.length);
if (len > 0) {
out.write(buf, 0, len);
out.flush();
}
}
} catch (IOException e) {
close(true);
}
});
signalChannelOpenSuccess();
f.setOpened();
} catch (Throwable t) {
Throwable e = GenericUtils.peelException(t);
signalChannelOpenFailure(e);
f.setException(e);
}
return f;
}
private void closeImmediately0() {
// We need to close the channel immediately to remove it from the
// server session's channel table and *not* send a packet to the
// client. A notification was already sent by our caller, or will
// be sent after we return.
//
super.close(true);
// We also need to close the socket.
Socket.close(handle);
try {
if ((forwarder != null) && (!forwarder.isDone())) {
forwarder.cancel(true);
}
} finally {
forwarder = null;
}
try {
if ((forwardService != null) && shutdownForwarder) {
Collection<?> runners = forwardService.shutdownNow();
if (log.isDebugEnabled()) {
log.debug("Shut down runners count=" + GenericUtils.size(runners));
}
}
} finally {
forwardService = null;
shutdownForwarder = false;
}
}
@Override
public CloseFuture close(boolean immediately) {
return super.close(immediately).addListener(sshFuture -> closeImmediately0());
}
@Override
protected void doWriteData(byte[] data, int off, long len) throws IOException {
ValidateUtils.checkTrue(len <= Integer.MAX_VALUE, "Data length exceeds int boundaries: %d", len);
int result = Socket.send(handle, data, off, (int) len);
if (result < Status.APR_SUCCESS) {
throwException(result);
}
}
@Override
protected void doWriteExtendedData(byte[] data, int off, long len) throws IOException {
throw new UnsupportedOperationException("AgentForward channel does not support extended data");
}
/**
* transform an APR error number in a more fancy exception
*
* @param code APR error code
* @throws java.io.IOException the produced exception for the given APR error number
*/
private static void throwException(int code) throws IOException {
throw new IOException(org.apache.tomcat.jni.Error.strerror(-code) + " (code: " + code + ")");
}
}