1 /*
2 * Copyright (C) 2008, Robin Rosenberg <robin.rosenberg@dewire.com>
3 * Copyright (C) 2008, Shawn O. Pearce <spearce@spearce.org> and others
4 *
5 * This program and the accompanying materials are made available under the
6 * terms of the Eclipse Distribution License v. 1.0 which is available at
7 * https://www.eclipse.org/org/documents/edl-v10.php.
8 *
9 * SPDX-License-Identifier: BSD-3-Clause
10 */
11
12 package org.eclipse.jgit.transport;
13
14 import java.security.AccessController;
15 import java.security.PrivilegedAction;
16 import java.util.Iterator;
17 import java.util.ServiceLoader;
18
19 import org.eclipse.jgit.errors.TransportException;
20 import org.eclipse.jgit.lib.Constants;
21 import org.eclipse.jgit.util.FS;
22 import org.eclipse.jgit.util.SystemReader;
23
24 /**
25 * Creates and destroys SSH connections to a remote system.
26 * <p>
27 * Different implementations of the session factory may be used to control
28 * communicating with the end-user as well as reading their personal SSH
29 * configuration settings, such as known hosts and private keys.
30 * <p>
31 * A {@link org.eclipse.jgit.transport.RemoteSession} must be returned to the
32 * factory that created it. Callers are encouraged to retain the
33 * SshSessionFactory for the duration of the period they are using the Session.
34 */
35 public abstract class SshSessionFactory {
36 private static SshSessionFactory INSTANCE = loadSshSessionFactory();
37
38 private static SshSessionFactory loadSshSessionFactory() {
39 ServiceLoader<SshSessionFactory> loader = ServiceLoader.load(SshSessionFactory.class);
40 Iterator<SshSessionFactory> iter = loader.iterator();
41 if(iter.hasNext()) {
42 return iter.next();
43 }
44 return null;
45 }
46 /**
47 * Get the currently configured JVM-wide factory.
48 * <p>
49 * A factory is always available. By default the factory will read from the
50 * user's <code>$HOME/.ssh</code> and assume OpenSSH compatibility.
51 *
52 * @return factory the current factory for this JVM.
53 */
54 public static SshSessionFactory getInstance() {
55 return INSTANCE;
56 }
57
58 /**
59 * Change the JVM-wide factory to a different implementation.
60 *
61 * @param newFactory
62 * factory for future sessions to be created through. If null the
63 * default factory will be restored.s
64 */
65 public static void setInstance(SshSessionFactory newFactory) {
66 if (newFactory != null) {
67 INSTANCE = newFactory;
68 } else {
69 INSTANCE = loadSshSessionFactory();
70 }
71 }
72
73 /**
74 * Retrieves the local user name as defined by the system property
75 * "user.name".
76 *
77 * @return the user name
78 * @since 5.2
79 */
80 public static String getLocalUserName() {
81 return AccessController
82 .doPrivileged((PrivilegedAction<String>) () -> SystemReader
83 .getInstance().getProperty(Constants.OS_USER_NAME_KEY));
84 }
85
86 /**
87 * Open (or reuse) a session to a host.
88 * <p>
89 * A reasonable UserInfo that can interact with the end-user (if necessary)
90 * is installed on the returned session by this method.
91 * <p>
92 * The caller must connect the session by invoking <code>connect()</code> if
93 * it has not already been connected.
94 *
95 * @param uri
96 * URI information about the remote host
97 * @param credentialsProvider
98 * provider to support authentication, may be null.
99 * @param fs
100 * the file system abstraction which will be necessary to perform
101 * certain file system operations.
102 * @param tms
103 * Timeout value, in milliseconds.
104 * @return a session that can contact the remote host.
105 * @throws org.eclipse.jgit.errors.TransportException
106 * the session could not be created.
107 */
108 public abstract RemoteSession getSession(URIish uri,
109 CredentialsProvider credentialsProvider, FS fs, int tms)
110 throws TransportException;
111
112 /**
113 * Close (or recycle) a session to a host.
114 *
115 * @param session
116 * a session previously obtained from this factory's
117 * {@link #getSession(URIish, CredentialsProvider, FS, int)}
118 * method.
119 */
120 public void releaseSession(RemoteSession session) {
121 session.disconnect();
122 }
123 }