SshdSession.java
/*
* Copyright (C) 2018, Thomas Wolf <thomas.wolf@paranor.ch> and others
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Distribution License v. 1.0 which is available at
* https://www.eclipse.org/org/documents/edl-v10.php.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
package org.eclipse.jgit.transport.sshd;
import static java.text.MessageFormat.format;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.time.Duration;
import java.util.ArrayList;
import java.util.Collection;
import java.util.EnumSet;
import java.util.List;
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicReference;
import java.util.function.Supplier;
import org.apache.sshd.client.SshClient;
import org.apache.sshd.client.channel.ChannelExec;
import org.apache.sshd.client.channel.ClientChannelEvent;
import org.apache.sshd.client.session.ClientSession;
import org.apache.sshd.client.subsystem.sftp.SftpClient;
import org.apache.sshd.client.subsystem.sftp.SftpClient.CloseableHandle;
import org.apache.sshd.client.subsystem.sftp.SftpClient.CopyMode;
import org.apache.sshd.client.subsystem.sftp.SftpClientFactory;
import org.apache.sshd.common.session.Session;
import org.apache.sshd.common.session.SessionListener;
import org.apache.sshd.common.subsystem.sftp.SftpException;
import org.eclipse.jgit.annotations.NonNull;
import org.eclipse.jgit.internal.transport.sshd.SshdText;
import org.eclipse.jgit.transport.FtpChannel;
import org.eclipse.jgit.transport.RemoteSession;
import org.eclipse.jgit.transport.URIish;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* An implementation of {@link RemoteSession} based on Apache MINA sshd.
*
* @since 5.2
*/
public class SshdSession implements RemoteSession {
private static final Logger LOG = LoggerFactory
.getLogger(SshdSession.class);
private final CopyOnWriteArrayList<SessionCloseListener> listeners = new CopyOnWriteArrayList<>();
private final URIish uri;
private SshClient client;
private ClientSession session;
SshdSession(URIish uri, Supplier<SshClient> clientFactory) {
this.uri = uri;
this.client = clientFactory.get();
}
void connect(Duration timeout) throws IOException {
if (!client.isStarted()) {
client.start();
}
try {
String username = uri.getUser();
String host = uri.getHost();
int port = uri.getPort();
long t = timeout.toMillis();
if (t <= 0) {
session = client.connect(username, host, port).verify()
.getSession();
} else {
session = client.connect(username, host, port)
.verify(timeout.toMillis()).getSession();
}
session.addSessionListener(new SessionListener() {
@Override
public void sessionClosed(Session s) {
notifyCloseListeners();
}
});
// Authentication timeout is by default 2 minutes.
session.auth().verify(session.getAuthTimeout());
} catch (IOException e) {
disconnect(e);
throw e;
}
}
/**
* Adds a {@link SessionCloseListener} to this session. Has no effect if the
* given {@code listener} is already registered with this session.
*
* @param listener
* to add
*/
public void addCloseListener(@NonNull SessionCloseListener listener) {
listeners.addIfAbsent(listener);
}
/**
* Removes the given {@code listener}; has no effect if the listener is not
* currently registered with this session.
*
* @param listener
* to remove
*/
public void removeCloseListener(@NonNull SessionCloseListener listener) {
listeners.remove(listener);
}
private void notifyCloseListeners() {
for (SessionCloseListener l : listeners) {
try {
l.sessionClosed(this);
} catch (RuntimeException e) {
LOG.warn(SshdText.get().closeListenerFailed, e);
}
}
}
@Override
public Process exec(String commandName, int timeout) throws IOException {
@SuppressWarnings("resource")
ChannelExec exec = session.createExecChannel(commandName);
if (timeout <= 0) {
try {
exec.open().verify();
} catch (IOException | RuntimeException e) {
exec.close(true);
throw e;
}
} else {
try {
exec.open().verify(TimeUnit.SECONDS.toMillis(timeout));
} catch (IOException | RuntimeException e) {
exec.close(true);
throw new IOException(format(SshdText.get().sshCommandTimeout,
commandName, Integer.valueOf(timeout)), e);
}
}
return new SshdExecProcess(exec, commandName);
}
/**
* Obtain an {@link FtpChannel} to perform SFTP operations in this
* {@link SshdSession}.
*/
@Override
@NonNull
public FtpChannel getFtpChannel() {
return new SshdFtpChannel();
}
@Override
public void disconnect() {
disconnect(null);
}
private void disconnect(Throwable reason) {
try {
if (session != null) {
session.close();
session = null;
}
} catch (IOException e) {
if (reason != null) {
reason.addSuppressed(e);
} else {
LOG.error(SshdText.get().sessionCloseFailed, e);
}
} finally {
client.stop();
client = null;
}
}
private static class SshdExecProcess extends Process {
private final ChannelExec channel;
private final String commandName;
public SshdExecProcess(ChannelExec channel, String commandName) {
this.channel = channel;
this.commandName = commandName;
}
@Override
public OutputStream getOutputStream() {
return channel.getInvertedIn();
}
@Override
public InputStream getInputStream() {
return channel.getInvertedOut();
}
@Override
public InputStream getErrorStream() {
return channel.getInvertedErr();
}
@Override
public int waitFor() throws InterruptedException {
if (waitFor(-1L, TimeUnit.MILLISECONDS)) {
return exitValue();
}
return -1;
}
@Override
public boolean waitFor(long timeout, TimeUnit unit)
throws InterruptedException {
long millis = timeout >= 0 ? unit.toMillis(timeout) : -1L;
return channel
.waitFor(EnumSet.of(ClientChannelEvent.CLOSED), millis)
.contains(ClientChannelEvent.CLOSED);
}
@Override
public int exitValue() {
Integer exitCode = channel.getExitStatus();
if (exitCode == null) {
throw new IllegalThreadStateException(
format(SshdText.get().sshProcessStillRunning,
commandName));
}
return exitCode.intValue();
}
@Override
public void destroy() {
if (channel.isOpen()) {
channel.close(false);
}
}
}
/**
* Helper interface like {@link Supplier}, but possibly raising an
* {@link IOException}.
*
* @param <T>
* return type
*/
@FunctionalInterface
private interface FtpOperation<T> {
T call() throws IOException;
}
private class SshdFtpChannel implements FtpChannel {
private SftpClient ftp;
/** Current working directory. */
private String cwd = ""; //$NON-NLS-1$
@Override
public void connect(int timeout, TimeUnit unit) throws IOException {
if (timeout <= 0) {
session.getProperties().put(
SftpClient.SFTP_CHANNEL_OPEN_TIMEOUT,
Long.valueOf(Long.MAX_VALUE));
} else {
session.getProperties().put(
SftpClient.SFTP_CHANNEL_OPEN_TIMEOUT,
Long.valueOf(unit.toMillis(timeout)));
}
ftp = SftpClientFactory.instance().createSftpClient(session);
try {
cd(cwd);
} catch (IOException e) {
ftp.close();
}
}
@Override
public void disconnect() {
try {
ftp.close();
} catch (IOException e) {
LOG.error(SshdText.get().ftpCloseFailed, e);
}
}
@Override
public boolean isConnected() {
return session.isAuthenticated() && ftp.isOpen();
}
private String absolute(String path) {
if (path.isEmpty()) {
return cwd;
}
// Note: there is no path injection vulnerability here. If
// path has too many ".." components, we rely on the server
// catching it and returning an error.
if (path.charAt(0) != '/') {
if (cwd.charAt(cwd.length() - 1) == '/') {
return cwd + path;
}
return cwd + '/' + path;
}
return path;
}
private <T> T map(FtpOperation<T> op) throws IOException {
try {
return op.call();
} catch (IOException e) {
if (e instanceof SftpException) {
throw new FtpChannel.FtpException(e.getLocalizedMessage(),
((SftpException) e).getStatus(), e);
}
throw e;
}
}
@Override
public void cd(String path) throws IOException {
cwd = map(() -> ftp.canonicalPath(absolute(path)));
if (cwd.isEmpty()) {
cwd += '/';
}
}
@Override
public String pwd() throws IOException {
return cwd;
}
@Override
public Collection<DirEntry> ls(String path) throws IOException {
return map(() -> {
List<DirEntry> result = new ArrayList<>();
try (CloseableHandle handle = ftp.openDir(absolute(path))) {
AtomicReference<Boolean> atEnd = new AtomicReference<>(
Boolean.FALSE);
while (!atEnd.get().booleanValue()) {
List<SftpClient.DirEntry> chunk = ftp.readDir(handle,
atEnd);
if (chunk == null) {
break;
}
for (SftpClient.DirEntry remote : chunk) {
result.add(new DirEntry() {
@Override
public String getFilename() {
return remote.getFilename();
}
@Override
public long getModifiedTime() {
return remote.getAttributes()
.getModifyTime().toMillis();
}
@Override
public boolean isDirectory() {
return remote.getAttributes().isDirectory();
}
});
}
}
}
return result;
});
}
@Override
public void rmdir(String path) throws IOException {
map(() -> {
ftp.rmdir(absolute(path));
return null;
});
}
@Override
public void mkdir(String path) throws IOException {
map(() -> {
ftp.mkdir(absolute(path));
return null;
});
}
@Override
public InputStream get(String path) throws IOException {
return map(() -> ftp.read(absolute(path)));
}
@Override
public OutputStream put(String path) throws IOException {
return map(() -> ftp.write(absolute(path)));
}
@Override
public void rm(String path) throws IOException {
map(() -> {
ftp.remove(absolute(path));
return null;
});
}
@Override
public void rename(String from, String to) throws IOException {
map(() -> {
String src = absolute(from);
String dest = absolute(to);
try {
ftp.rename(src, dest, CopyMode.Atomic, CopyMode.Overwrite);
} catch (UnsupportedOperationException e) {
// Older server cannot do POSIX rename...
if (!src.equals(dest)) {
delete(dest);
ftp.rename(src, dest);
}
}
return null;
});
}
}
}