1 /*
2 * Copyright (C) 2008, Robin Rosenberg <robin.rosenberg@dewire.com>
3 * Copyright (C) 2008, Shawn O. Pearce <spearce@spearce.org>
4 * and other copyright owners as documented in the project's IP log.
5 *
6 * This program and the accompanying materials are made available
7 * under the terms of the Eclipse Distribution License v1.0 which
8 * accompanies this distribution, is reproduced below, and is
9 * available at http://www.eclipse.org/org/documents/edl-v10.php
10 *
11 * All rights reserved.
12 *
13 * Redistribution and use in source and binary forms, with or
14 * without modification, are permitted provided that the following
15 * conditions are met:
16 *
17 * - Redistributions of source code must retain the above copyright
18 * notice, this list of conditions and the following disclaimer.
19 *
20 * - Redistributions in binary form must reproduce the above
21 * copyright notice, this list of conditions and the following
22 * disclaimer in the documentation and/or other materials provided
23 * with the distribution.
24 *
25 * - Neither the name of the Eclipse Foundation, Inc. nor the
26 * names of its contributors may be used to endorse or promote
27 * products derived from this software without specific prior
28 * written permission.
29 *
30 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
31 * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
32 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
33 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
34 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
35 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
36 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
37 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
38 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
39 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
40 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
41 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
42 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
43 */
44
45 package org.eclipse.jgit.transport;
46
47 import java.security.AccessController;
48 import java.security.PrivilegedAction;
49
50 import org.eclipse.jgit.errors.TransportException;
51 import org.eclipse.jgit.lib.Constants;
52 import org.eclipse.jgit.util.FS;
53 import org.eclipse.jgit.util.SystemReader;
54
55 /**
56 * Creates and destroys SSH connections to a remote system.
57 * <p>
58 * Different implementations of the session factory may be used to control
59 * communicating with the end-user as well as reading their personal SSH
60 * configuration settings, such as known hosts and private keys.
61 * <p>
62 * A {@link org.eclipse.jgit.transport.RemoteSession} must be returned to the
63 * factory that created it. Callers are encouraged to retain the
64 * SshSessionFactory for the duration of the period they are using the Session.
65 */
66 public abstract class SshSessionFactory {
67 private static SshSessionFactory INSTANCE = new DefaultSshSessionFactory();
68
69 /**
70 * Get the currently configured JVM-wide factory.
71 * <p>
72 * A factory is always available. By default the factory will read from the
73 * user's <code>$HOME/.ssh</code> and assume OpenSSH compatibility.
74 *
75 * @return factory the current factory for this JVM.
76 */
77 public static SshSessionFactory getInstance() {
78 return INSTANCE;
79 }
80
81 /**
82 * Change the JVM-wide factory to a different implementation.
83 *
84 * @param newFactory
85 * factory for future sessions to be created through. If null the
86 * default factory will be restored.s
87 */
88 public static void setInstance(SshSessionFactory newFactory) {
89 if (newFactory != null)
90 INSTANCE = newFactory;
91 else
92 INSTANCE = new DefaultSshSessionFactory();
93 }
94
95 /**
96 * Retrieves the local user name as defined by the system property
97 * "user.name".
98 *
99 * @return the user name
100 * @since 5.2
101 */
102 public static String getLocalUserName() {
103 return AccessController.doPrivileged(new PrivilegedAction<String>() {
104 @Override
105 public String run() {
106 return SystemReader.getInstance()
107 .getProperty(Constants.OS_USER_NAME_KEY);
108 }
109 });
110 }
111
112 /**
113 * Open (or reuse) a session to a host.
114 * <p>
115 * A reasonable UserInfo that can interact with the end-user (if necessary)
116 * is installed on the returned session by this method.
117 * <p>
118 * The caller must connect the session by invoking <code>connect()</code> if
119 * it has not already been connected.
120 *
121 * @param uri
122 * URI information about the remote host
123 * @param credentialsProvider
124 * provider to support authentication, may be null.
125 * @param fs
126 * the file system abstraction which will be necessary to perform
127 * certain file system operations.
128 * @param tms
129 * Timeout value, in milliseconds.
130 * @return a session that can contact the remote host.
131 * @throws org.eclipse.jgit.errors.TransportException
132 * the session could not be created.
133 */
134 public abstract RemoteSession getSession(URIish uri,
135 CredentialsProvider credentialsProvider, FS fs, int tms)
136 throws TransportException;
137
138 /**
139 * Close (or recycle) a session to a host.
140 *
141 * @param session
142 * a session previously obtained from this factory's
143 * {@link #getSession(URIish, CredentialsProvider, FS, int)}
144 * method.
145 */
146 public void releaseSession(RemoteSession session) {
147 session.disconnect();
148 }
149 }