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 *      https://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 * <p>
035 * The standard output and standard error streams of the remote process are transmitted over the same connection, readable from the input stream returned by
036 * {@link org.apache.commons.net.bsd.RExecClient#getInputStream getInputStream()}
037 * </p>
038 * <p>
039 * Unlike RExecClient and RCommandClient, it is not possible to tell the rlogind daemon to return the standard error stream over a separate connection.
040 * {@link org.apache.commons.net.bsd.RExecClient#getErrorStream getErrorStream()} will always return null. The standard input of the remote process can be
041 * written to through the output stream returned by {@link org.apache.commons.net.bsd.RExecClient#getOutputStream getOutputSream()}
042 * </p>
043 *
044 * @see org.apache.commons.net.SocketClient
045 * @see RExecClient
046 * @see RCommandClient
047 */
048public class RLoginClient extends RCommandClient {
049
050    /**
051     * The default rlogin port. Set to 513 in BSD Unix and according to RFC 1282.
052     */
053    public static final int DEFAULT_PORT = 513;
054
055    /**
056     * The default RLoginClient constructor. Initializes the default port to {@code DEFAULT_PORT}.
057     */
058    public RLoginClient() {
059        setDefaultPort(DEFAULT_PORT);
060    }
061
062    /**
063     * Same as the other rlogin method, but no terminal speed is defined.
064     *
065     * @param localUserName  the local user
066     * @param remoteUserName the remote user
067     * @param terminalType   the terminal type
068     * @throws IOException on error
069     */
070    public void rlogin(final String localUserName, final String remoteUserName, final String terminalType) throws IOException {
071        rexec(localUserName, remoteUserName, terminalType, false);
072    }
073
074    /**
075     * 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
076     * 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
077     * typically be able to detect the termination of the remote login shell after reaching end of file on its standard output (accessible through
078     * {@link #getInputStream getInputStream()}). Disconnecting from the server or closing the process streams before reaching end of file will terminate the
079     * remote login shell in most cases.
080     * <p>
081     * 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
082     * output stream of the RLoginClient and write the password to the input stream of the RLoginClient.
083     * </p>
084     *
085     * @param localUserName  The user account on the local machine that is trying to log in to the remote host.
086     * @param remoteUserName The account name on the server that is being logged in to.
087     * @param terminalType   The name of the user's terminal (e.g., "vt100", "network", etc.)
088     * @param terminalSpeed  The speed of the user's terminal, expressed as a baud rate or bps (e.g., 9600 or 38400)
089     * @throws IOException If the rlogin() attempt fails. The exception will contain a message indicating the nature of the failure.
090     */
091    public void rlogin(final String localUserName, final String remoteUserName, final String terminalType, final int terminalSpeed) throws IOException {
092        rexec(localUserName, remoteUserName, terminalType + "/" + terminalSpeed, false);
093    }
094
095}