001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017
018package org.apache.commons.net.bsd;
019
020import java.io.IOException;
021
022/**
023 * RLoginClient is very similar to {@link org.apache.commons.net.bsd.RCommandClient}, from which it is derived, and uses the rcmd() facility implemented in
024 * 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
025 * remote machine from a trusted host, sometimes without issuing a password. The trust relationship is the same as described in the documentation for
026 * {@link org.apache.commons.net.bsd.RCommandClient}.
027 * <p>
028 * 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
029 * 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
030 * server, call the {@link #rlogin rlogin() } method, and then fetch the connection's input and output streams. Interaction with the remote command is
031 * controlled entirely through the I/O streams. Once you have finished processing the streams, you should invoke
032 * {@link org.apache.commons.net.bsd.RExecClient#disconnect disconnect() } to clean up properly.
033 * <p>
034 * The standard output and standard error streams of the remote process are transmitted over the same connection, readable from the input stream returned by
035 * {@link org.apache.commons.net.bsd.RExecClient#getInputStream getInputStream() }
036 * <p>
037 * Unlike RExecClient and RCommandClient, it is not possible to tell the rlogind daemon to return the standard error stream over a separate connection.
038 * {@link org.apache.commons.net.bsd.RExecClient#getErrorStream getErrorStream() } will always return null. The standard input of the remote process can be
039 * written to through the output stream returned by {@link org.apache.commons.net.bsd.RExecClient#getOutputStream getOutputSream() }
040 *
041 * @see org.apache.commons.net.SocketClient
042 * @see RExecClient
043 * @see RCommandClient
044 */
045
046public class RLoginClient extends RCommandClient {
047    /**
048     * The default rlogin port. Set to 513 in BSD Unix and according to RFC 1282.
049     */
050    public static final int DEFAULT_PORT = 513;
051
052    /**
053     * The default RLoginClient constructor. Initializes the default port to <code> DEFAULT_PORT </code>.
054     */
055    public RLoginClient() {
056        setDefaultPort(DEFAULT_PORT);
057    }
058
059    /**
060     * Same as the other rlogin method, but no terminal speed is defined.
061     *
062     * @param localUsername  the local user
063     * @param remoteUsername the remote user
064     * @param terminalType   the terminal type
065     * @throws IOException on error
066     */
067    public void rlogin(final String localUsername, final String remoteUsername, final String terminalType) throws IOException {
068        rexec(localUsername, remoteUsername, terminalType, false);
069    }
070
071    /**
072     * 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
073     * 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
074     * typically be able to detect the termination of the remote login shell after reaching end of file on its standard output (accessible through
075     * {@link #getInputStream getInputStream()}). Disconnecting from the server or closing the process streams before reaching end of file will terminate the
076     * remote login shell in most cases.
077     * <p>
078     * 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
079     * output stream of the RLoginClient and write the password to the input stream of the RLoginClient.
080     *
081     * @param localUsername  The user account on the local machine that is trying to log in to the remote host.
082     * @param remoteUsername The account name on the server that is being logged in to.
083     * @param terminalType   The name of the user's terminal (e.g., "vt100", "network", etc.)
084     * @param terminalSpeed  The speed of the user's terminal, expressed as a baud rate or bps (e.g., 9600 or 38400)
085     * @throws IOException If the rlogin() attempt fails. The exception will contain a message indicating the nature of the failure.
086     */
087    public void rlogin(final String localUsername, final String remoteUsername, final String terminalType, final int terminalSpeed) throws IOException {
088        rexec(localUsername, remoteUsername, terminalType + "/" + terminalSpeed, false);
089    }
090
091}