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1   /*
2    * Copyright (C) 2018, Markus Duft <markus.duft@ssi-schaefer.com>
3    * and other copyright owners as documented in the project's IP log.
4    *
5    * This program and the accompanying materials are made available
6    * under the terms of the Eclipse Distribution License v1.0 which
7    * accompanies this distribution, is reproduced below, and is
8    * available at http://www.eclipse.org/org/documents/edl-v10.php
9    *
10   * All rights reserved.
11   *
12   * Redistribution and use in source and binary forms, with or
13   * without modification, are permitted provided that the following
14   * conditions are met:
15   *
16   * - Redistributions of source code must retain the above copyright
17   *   notice, this list of conditions and the following disclaimer.
18   *
19   * - Redistributions in binary form must reproduce the above
20   *   copyright notice, this list of conditions and the following
21   *   disclaimer in the documentation and/or other materials provided
22   *   with the distribution.
23   *
24   * - Neither the name of the Eclipse Foundation, Inc. nor the
25   *   names of its contributors may be used to endorse or promote
26   *   products derived from this software without specific prior
27   *   written permission.
28   *
29   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
30   * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
31   * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
32   * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
33   * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
34   * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
35   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
36   * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
37   * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
38   * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
39   * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
40   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
41   * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
42   */
43  package org.eclipse.jgit.util;
44  
45  import java.io.IOException;
46  import java.text.MessageFormat;
47  
48  import org.eclipse.jgit.annotations.Nullable;
49  import org.eclipse.jgit.errors.CommandFailedException;
50  import org.eclipse.jgit.internal.JGitText;
51  import org.eclipse.jgit.transport.CredentialsProvider;
52  import org.eclipse.jgit.transport.RemoteSession;
53  import org.eclipse.jgit.transport.SshSessionFactory;
54  import org.eclipse.jgit.transport.URIish;
55  import org.eclipse.jgit.util.io.MessageWriter;
56  import org.eclipse.jgit.util.io.StreamCopyThread;
57  
58  /**
59   * Extra utilities to support usage of SSH.
60   *
61   * @since 5.0
62   */
63  public class SshSupport {
64  
65  	/**
66  	 * Utility to execute a remote SSH command and read the first line of
67  	 * output.
68  	 *
69  	 * @param sshUri
70  	 *            the SSH remote URI
71  	 * @param provider
72  	 *            the {@link CredentialsProvider} or <code>null</code>.
73  	 * @param fs
74  	 *            the {@link FS} implementation passed to
75  	 *            {@link SshSessionFactory}
76  	 * @param command
77  	 *            the remote command to execute.
78  	 * @param timeout
79  	 *            a timeout in seconds. The timeout may be exceeded in corner
80  	 *            cases.
81  	 * @return The entire output read from stdout.
82  	 * @throws IOException
83  	 * @throws CommandFailedException
84  	 *             if the ssh command execution failed, error message contains
85  	 *             the content of stderr.
86  	 */
87  	public static String runSshCommand(URIish sshUri,
88  			@Nullable CredentialsProvider provider, FS fs, String command,
89  			int timeout) throws IOException, CommandFailedException {
90  		RemoteSession session = null;
91  		Process process = null;
92  		StreamCopyThread errorThread = null;
93  		StreamCopyThread outThread = null;
94  		CommandFailedException failure = null;
95  		@SuppressWarnings("resource")
96  		MessageWriter stderr = new MessageWriter();
97  		try (MessageWriter stdout = new MessageWriter()) {
98  			session = SshSessionFactory.getInstance().getSession(sshUri,
99  					provider, fs, 1000 * timeout);
100 			process = session.exec(command, 0);
101 			errorThread = new StreamCopyThread(process.getErrorStream(),
102 					stderr.getRawStream());
103 			errorThread.start();
104 			outThread = new StreamCopyThread(process.getInputStream(),
105 					stdout.getRawStream());
106 			outThread.start();
107 			try {
108 				// waitFor with timeout has a bug - JSch' exitValue() throws the
109 				// wrong exception type :(
110 				if (process.waitFor() == 0) {
111 					return stdout.toString();
112 				} else {
113 					return null; // still running after timeout
114 				}
115 			} catch (InterruptedException e) {
116 				return null; // error
117 			}
118 		} finally {
119 			if (errorThread != null) {
120 				try {
121 					errorThread.halt();
122 				} catch (InterruptedException e) {
123 					// Stop waiting and return anyway.
124 				} finally {
125 					errorThread = null;
126 				}
127 			}
128 			if (outThread != null) {
129 				try {
130 					outThread.halt();
131 				} catch (InterruptedException e) {
132 					// Stop waiting and return anyway.
133 				} finally {
134 					outThread = null;
135 				}
136 			}
137 			if (process != null) {
138 				if (process.exitValue() != 0) {
139 					failure = new CommandFailedException(process.exitValue(),
140 							MessageFormat.format(
141 							JGitText.get().sshCommandFailed, command,
142 							stderr.toString()));
143 				}
144 				process.destroy();
145 			}
146 			stderr.close();
147 			if (session != null) {
148 				SshSessionFactory.getInstance().releaseSession(session);
149 			}
150 			if (failure != null) {
151 				throw failure;
152 			}
153 		}
154 	}
155 
156 }