com.dalsemi.shell.server.telnet
Class TelnetServer

java.lang.Object
  |
  +--java.lang.Thread
        |
        +--com.dalsemi.shell.server.Server
              |
              +--com.dalsemi.shell.server.telnet.TelnetServer

public class TelnetServer

extends Server

A simple server that uses the Telnet protocol as described in RFC 854. This server uses a ServerSocket to listen on the specified port (defaults to port 23) for Telnet connection requests. For each connection made, a Telnet session is created. All command processing is handled by the Telnet session, not this server.

Fields inherited from class com.dalsemi.shell.server.Server

sessions, shutdown

Fields inherited from class java.lang.Thread

MAX_PRIORITY, MIN_PRIORITY, NORM_PRIORITY

Constructor Summary

TelnetServer()
Prepares the Telnet server to listen on the well known Telnet port (23).

TelnetServer(int port)
Prepares the Telnet server to listen on an arbitrary port.

Method Summary

protected Session	acceptNewSession() Listens on the connection port for connection requests.
protected void	closeAllPorts() Closes the ServerSocket used to listen for connections.
static java.lang.String	getWelcomeFile() Gets the name of the file to be displayed when after a user logs in to this server.
static boolean	isRootAllowed() Indicates whether root access is allowed to this Telnet server.

Methods inherited from class com.dalsemi.shell.server.Server

broadcast, checkForNewSessions, getConnectedUsers, run, sessionEnded, shutDown

Methods inherited from class java.lang.Thread

activeCount, checkAccess, countStackFrames, currentThread, destroy, dumpStack, enumerate, getName, getPriority, getThreadGroup, interrupt, interrupted, isAlive, isDaemon, isInterrupted, join, join, join, resume, setDaemon, setName, setPriority, sleep, sleep, start, stop, stop, suspend, toString, yield

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

TelnetServer

public TelnetServer()
             throws java.io.IOException

Prepares the Telnet server to listen on the well known Telnet port (23). The server will not be started and no connections will be accepted until its run() method is executed.

TelnetServer

public TelnetServer(int port)
             throws java.io.IOException

Prepares the Telnet server to listen on an arbitrary port. The server will not be started and no connections will be accepted until its run() method is executed.

Method Detail

getWelcomeFile

public static java.lang.String getWelcomeFile()

Gets the name of the file to be displayed when after a user logs in to this server. This file is specified by setting the "TELNET_WELCOME" environment variable equal to the name of the file. This method will always return the value the variable had when the server was constructed. Changing the value of environment variable after creating the server will have no effect.

Returns:

the name of the welcome file to display, or null if no welcome file was specified

isRootAllowed

public static boolean isRootAllowed()

Indicates whether root access is allowed to this Telnet server. This is specified with the environment variable "TELNET_ROOT_ALLOWED". Set the variable to "false" to disallow root login. All other values will be interpreted as true and root logins will be accepted. This method will always return the value the variable had when the server was constructed. Changing the value of environment variable after creating the server will have no effect.

Returns:

true if root is allowed to login

acceptNewSession

protected Session acceptNewSession()

Listens on the connection port for connection requests. Once a request is made, it creates, initializes, and returns a new TelnetSession to handle that request. This method will block until a connection is made.

Returns:

a new TelnetSession

Overrides:

acceptNewSession in class Server

closeAllPorts

protected void closeAllPorts()
                      throws java.io.IOException

Closes the ServerSocket used to listen for connections.

Overrides:

closeAllPorts in class Server