org.apache.sshd.agent.unix.AgentClient Maven / Gradle / Ivy
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* 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.InterruptedIOException;
import java.io.StreamCorruptedException;
import java.util.Objects;
import java.util.Queue;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicBoolean;
import org.apache.sshd.agent.common.AbstractAgentProxy;
import org.apache.sshd.common.FactoryManager;
import org.apache.sshd.common.FactoryManagerHolder;
import org.apache.sshd.common.PropertyResolverUtils;
import org.apache.sshd.common.SshException;
import org.apache.sshd.common.util.buffer.Buffer;
import org.apache.sshd.common.util.buffer.ByteArrayBuffer;
import org.apache.sshd.common.util.threads.CloseableExecutorService;
import org.apache.sshd.common.util.threads.ThreadUtils;
import org.apache.tomcat.jni.Local;
import org.apache.tomcat.jni.Pool;
import org.apache.tomcat.jni.Socket;
import org.apache.tomcat.jni.Status;
/**
* A client for a remote SSH agent
*/
public class AgentClient extends AbstractAgentProxy implements Runnable, FactoryManagerHolder {
/**
* Time to wait for new incoming messages before checking if the client is still active
*/
public static final String MESSAGE_POLL_FREQUENCY = "agent-client-message-poll-time";
/**
* Default value for {@value #MESSAGE_POLL_FREQUENCY}
*/
public static final long DEFAULT_MESSAGE_POLL_FREQUENCY = TimeUnit.MINUTES.toMillis(2L);
private final String authSocket;
private final FactoryManager manager;
private final long pool;
private final long handle;
private final Buffer receiveBuffer;
private final Queue messages;
private Future pumper;
private final AtomicBoolean open = new AtomicBoolean(true);
public AgentClient(FactoryManager manager, String authSocket) throws IOException {
this(manager, authSocket, null);
}
public AgentClient(FactoryManager manager, String authSocket, CloseableExecutorService executor) throws IOException {
super((executor == null) ? ThreadUtils.newSingleThreadExecutor("AgentClient[" + authSocket + "]") : executor);
this.manager = Objects.requireNonNull(manager, "No factory manager instance provided");
this.authSocket = authSocket;
try {
AprLibrary aprLibInstance = AprLibrary.getInstance();
pool = Pool.create(aprLibInstance.getRootPool());
handle = Local.create(authSocket, pool);
int result = Local.connect(handle, 0);
if (result != Status.APR_SUCCESS) {
throwException(result);
}
receiveBuffer = new ByteArrayBuffer();
messages = new ArrayBlockingQueue<>(10);
CloseableExecutorService service = getExecutorService();
pumper = service.submit(this);
} catch (IOException e) {
throw e;
} catch (Exception e) {
throw new SshException(e);
}
}
@Override
public FactoryManager getFactoryManager() {
return manager;
}
public String getAuthSocket() {
return authSocket;
}
@Override
public boolean isOpen() {
return open.get();
}
@Override
public void run() {
try {
byte[] buf = new byte[1024];
while (isOpen()) {
int result = Socket.recv(handle, buf, 0, buf.length);
if (result < Status.APR_SUCCESS) {
throwException(result);
}
messageReceived(new ByteArrayBuffer(buf, 0, result));
}
} catch (Exception e) {
boolean debugEnabled = log.isDebugEnabled();
if (isOpen()) {
log.warn("run({}) {} while still open: {}",
this, e.getClass().getSimpleName(), e.getMessage());
if (debugEnabled) {
log.debug("run(" + this + ") open client exception", e);
}
} else {
if (debugEnabled) {
log.debug("run(" + this + ") closed client loop exception", e);
}
}
} finally {
try {
close();
} catch (IOException e) {
if (log.isDebugEnabled()) {
log.debug("run({}) {} while closing: {}",
this, e.getClass().getSimpleName(), e.getMessage());
}
}
}
}
protected void messageReceived(Buffer buffer) throws Exception {
Buffer message = null;
synchronized (receiveBuffer) {
receiveBuffer.putBuffer(buffer);
if (receiveBuffer.available() >= Integer.BYTES) {
int rpos = receiveBuffer.rpos();
int len = receiveBuffer.getInt();
// Protect against malicious or corrupted packets
if (len < 0) {
throw new StreamCorruptedException("Illogical message length: " + len);
}
receiveBuffer.rpos(rpos);
if (receiveBuffer.available() >= (Integer.BYTES + len)) {
message = new ByteArrayBuffer(receiveBuffer.getBytes());
receiveBuffer.compact();
}
}
}
if (message != null) {
synchronized (messages) {
messages.offer(message);
messages.notifyAll();
}
}
}
@Override
public void close() throws IOException {
if (open.getAndSet(false)) {
Socket.close(handle);
}
// make any waiting thread aware of the closure
synchronized (messages) {
messages.notifyAll();
}
if ((pumper != null) && (!pumper.isDone())) {
pumper.cancel(true);
}
super.close();
}
@Override
protected synchronized Buffer request(Buffer buffer) throws IOException {
int wpos = buffer.wpos();
buffer.wpos(0);
buffer.putUInt(wpos - 4);
buffer.wpos(wpos);
synchronized (messages) {
int result = Socket.send(handle, buffer.array(), buffer.rpos(), buffer.available());
if (result < Status.APR_SUCCESS) {
throwException(result);
}
return waitForMessageBuffer();
}
}
// NOTE: assumes messages lock is obtained prior to calling this method
protected Buffer waitForMessageBuffer() throws IOException {
FactoryManager mgr = getFactoryManager();
long idleTimeout = PropertyResolverUtils.getLongProperty(
mgr, MESSAGE_POLL_FREQUENCY, DEFAULT_MESSAGE_POLL_FREQUENCY);
if (idleTimeout <= 0L) {
idleTimeout = DEFAULT_MESSAGE_POLL_FREQUENCY;
}
boolean traceEnabled = log.isTraceEnabled();
for (int count = 1;; count++) {
if (!isOpen()) {
throw new SshException("Client is being closed");
}
if (!messages.isEmpty()) {
return messages.poll();
}
if (traceEnabled) {
log.trace("waitForMessageBuffer({}) wait iteration #{}", this, count);
}
try {
messages.wait(idleTimeout);
} catch (InterruptedException e) {
throw (IOException) new InterruptedIOException("Interrupted while waiting for messages at iteration #" + count)
.initCause(e);
}
}
}
/**
* 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
*/
protected void throwException(int code) throws IOException {
throw new IOException(org.apache.tomcat.jni.Error.strerror(-code) + " (code: " + code + ")");
}
@Override
public String toString() {
return getClass().getSimpleName() + "[socket=" + getAuthSocket() + "]";
}
}
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