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// Copyright (C) 2008 The Android Open Source Project
//
// Licensed 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 com.google.gerrit.sshd;
import com.google.gerrit.entities.Account;
import com.google.gerrit.server.IdentifiedUser;
import com.google.gerrit.server.config.AnonymousCowardName;
import com.google.gerrit.server.config.CanonicalWebUrl;
import com.google.gerrit.server.ssh.SshInfo;
import com.google.gerrit.sshd.SshScope.Context;
import com.google.inject.Inject;
import com.google.inject.Provider;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.MalformedURLException;
import java.net.URL;
import org.apache.sshd.common.io.IoInputStream;
import org.apache.sshd.common.io.IoOutputStream;
import org.apache.sshd.common.util.buffer.ByteArrayBuffer;
import org.apache.sshd.server.Environment;
import org.apache.sshd.server.ExitCallback;
import org.apache.sshd.server.channel.ChannelSession;
import org.apache.sshd.server.command.AsyncCommand;
import org.apache.sshd.server.command.Command;
import org.apache.sshd.server.session.ServerSession;
import org.apache.sshd.server.session.ServerSessionAware;
import org.apache.sshd.server.shell.ShellFactory;
import org.eclipse.jgit.lib.Constants;
import org.eclipse.jgit.util.SystemReader;
/**
* Dummy shell which prints a message and terminates.
*
* <p>This implementation is used to ensure clients who try to SSH directly to this server without
* supplying a command will get a reasonable error message, but cannot continue further.
*/
class NoShell implements ShellFactory {
private final Provider<SendMessage> shell;
@Inject
NoShell(Provider<SendMessage> shell) {
this.shell = shell;
}
@Override
public Command createShell(ChannelSession channel) {
return shell.get();
}
/**
* When AsyncCommand is implemented by a command as below, the usual blocking streams aren't set.
*
* @see org.apache.sshd.server.command.AsyncCommand
*/
static class SendMessage implements AsyncCommand, ServerSessionAware {
private final Provider<MessageFactory> messageFactory;
private final SshScope sshScope;
private IoInputStream in;
private IoOutputStream out;
private IoOutputStream err;
private ExitCallback exit;
private Context context;
@Inject
SendMessage(Provider<MessageFactory> messageFactory, SshScope sshScope) {
this.messageFactory = messageFactory;
this.sshScope = sshScope;
}
@Override
public void setIoInputStream(IoInputStream in) {
this.in = in;
}
@Override
public void setIoOutputStream(IoOutputStream out) {
this.out = out;
}
@Override
public void setIoErrorStream(IoOutputStream err) {
this.err = err;
}
@Override
public void setInputStream(InputStream in) {
// ignored
}
@Override
public void setOutputStream(OutputStream out) {
// ignore
}
@Override
public void setErrorStream(OutputStream err) {
// ignore
}
@Override
public void setExitCallback(ExitCallback callback) {
this.exit = callback;
}
@Override
public void setSession(ServerSession session) {
SshSession s = session.getAttribute(SshSession.KEY);
this.context = sshScope.newContext(s, "");
}
@Override
public void start(ChannelSession channel, Environment env) throws IOException {
Context old = sshScope.set(context);
String message;
try {
message = messageFactory.get().getMessage();
} finally {
sshScope.set(old);
}
err.writeBuffer(new ByteArrayBuffer(Constants.encode(message)));
in.close();
out.close();
err.close();
exit.onExit(127);
}
@Override
public void destroy(ChannelSession channel) {}
}
static class MessageFactory {
private final IdentifiedUser user;
private final SshInfo sshInfo;
private final Provider<String> urlProvider;
private final String anonymousCowardName;
@Inject
MessageFactory(
IdentifiedUser user,
SshInfo sshInfo,
@CanonicalWebUrl Provider<String> urlProvider,
@AnonymousCowardName String anonymousCowardName) {
this.user = user;
this.sshInfo = sshInfo;
this.urlProvider = urlProvider;
this.anonymousCowardName = anonymousCowardName;
}
String getMessage() {
StringBuilder msg = new StringBuilder();
msg.append("\r\n");
msg.append(" **** Welcome to Gerrit Code Review ****\r\n");
msg.append("\r\n");
Account account = user.getAccount();
String name = account.fullName();
if (name == null || name.isEmpty()) {
name = user.getUserName().orElse(anonymousCowardName);
}
msg.append(" Hi ");
msg.append(name);
msg.append(", you have successfully connected over SSH.");
msg.append("\r\n");
msg.append("\r\n");
msg.append(" Unfortunately, interactive shells are disabled.\r\n");
msg.append(" To clone a hosted Git repository, use:\r\n");
msg.append("\r\n");
if (!sshInfo.getHostKeys().isEmpty()) {
String host = sshInfo.getHostKeys().get(0).getHost();
if (host.startsWith("*:")) {
host = getGerritHost() + host.substring(1);
}
msg.append(" git clone ssh://");
if (user.getUserName().isPresent()) {
msg.append(user.getUserName().get());
msg.append("@");
}
msg.append(host);
msg.append("/");
msg.append("REPOSITORY_NAME.git");
msg.append("\r\n");
}
msg.append("\r\n");
return msg.toString();
}
private String getGerritHost() {
String url = urlProvider.get();
if (url != null) {
try {
return new URL(url).getHost();
} catch (MalformedURLException e) {
// Ignored
}
}
return SystemReader.getInstance().getHostname();
}
}
}