1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * https://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17
18 package org.apache.commons.net.bsd;
19
20 import java.io.IOException;
21
22 /**
23 * RLoginClient is very similar to {@link org.apache.commons.net.bsd.RCommandClient}, from which it is derived, and uses the rcmd() facility implemented in
24 * RCommandClient to implement the functionality of the rlogin command that first appeared in 4.2BSD Unix. rlogin is a command used to log in to a
25 * remote machine from a trusted host, sometimes without issuing a password. The trust relationship is the same as described in the documentation for
26 * {@link org.apache.commons.net.bsd.RCommandClient}.
27 * <p>
28 * As with virtually all the client classes in org.apache.commons.net, this class derives from SocketClient. But it relies on the connection methods defined
29 * in RcommandClient which ensure that the local Socket will originate from an acceptable rshell port. The way to use RLoginClient is to first connect to the
30 * server, call the {@link #rlogin rlogin()} method, and then fetch the connection's input and output streams. Interaction with the remote command is
31 * controlled entirely through the I/O streams. Once you have finished processing the streams, you should invoke
32 * {@link org.apache.commons.net.bsd.RExecClient#disconnect disconnect()} to clean up properly.
33 * </p>
34 * <p>
35 * The standard output and standard error streams of the remote process are transmitted over the same connection, readable from the input stream returned by
36 * {@link org.apache.commons.net.bsd.RExecClient#getInputStream getInputStream()}
37 * </p>
38 * <p>
39 * Unlike RExecClient and RCommandClient, it is not possible to tell the rlogind daemon to return the standard error stream over a separate connection.
40 * {@link org.apache.commons.net.bsd.RExecClient#getErrorStream getErrorStream()} will always return null. The standard input of the remote process can be
41 * written to through the output stream returned by {@link org.apache.commons.net.bsd.RExecClient#getOutputStream getOutputSream()}
42 * </p>
43 *
44 * @see org.apache.commons.net.SocketClient
45 * @see RExecClient
46 * @see RCommandClient
47 */
48 public class RLoginClient extends RCommandClient {
49
50 /**
51 * The default rlogin port. Set to 513 in BSD Unix and according to RFC 1282.
52 */
53 public static final int DEFAULT_PORT = 513;
54
55 /**
56 * The default RLoginClient constructor. Initializes the default port to {@code DEFAULT_PORT}.
57 */
58 public RLoginClient() {
59 setDefaultPort(DEFAULT_PORT);
60 }
61
62 /**
63 * Same as the other rlogin method, but no terminal speed is defined.
64 *
65 * @param localUserName the local user
66 * @param remoteUserName the remote user
67 * @param terminalType the terminal type
68 * @throws IOException on error
69 */
70 public void rlogin(final String localUserName, final String remoteUserName, final String terminalType) throws IOException {
71 rexec(localUserName, remoteUserName, terminalType, false);
72 }
73
74 /**
75 * Logins into a remote machine through the rlogind daemon on the server to which the RLoginClient is connected. After calling this method, you may interact
76 * with the remote login shell through its standard input and output streams. Standard error is sent over the same stream as standard output. You will
77 * typically be able to detect the termination of the remote login shell after reaching end of file on its standard output (accessible through
78 * {@link #getInputStream getInputStream()}). Disconnecting from the server or closing the process streams before reaching end of file will terminate the
79 * remote login shell in most cases.
80 * <p>
81 * If user authentication fails, the rlogind daemon will request that a password be entered interactively. You will be able to read the prompt from the
82 * output stream of the RLoginClient and write the password to the input stream of the RLoginClient.
83 * </p>
84 *
85 * @param localUserName The user account on the local machine that is trying to log in to the remote host.
86 * @param remoteUserName The account name on the server that is being logged in to.
87 * @param terminalType The name of the user's terminal (e.g., "vt100", "network", etc.)
88 * @param terminalSpeed The speed of the user's terminal, expressed as a baud rate or bps (e.g., 9600 or 38400)
89 * @throws IOException If the rlogin() attempt fails. The exception will contain a message indicating the nature of the failure.
90 */
91 public void rlogin(final String localUserName, final String remoteUserName, final String terminalType, final int terminalSpeed) throws IOException {
92 rexec(localUserName, remoteUserName, terminalType + "/" + terminalSpeed, false);
93 }
94
95 }