src/main/java/ch/ethz/ssh2/Session.java - platform/external/ganymed-ssh2 - Git at Google

 /*
  * Copyright (c) 2006-2011 Christian Plattner. All rights reserved.
  * Please refer to the LICENSE.txt for licensing details.
  */
 package ch.ethz.ssh2;

 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
 import java.security.SecureRandom;

 import ch.ethz.ssh2.channel.Channel;
 import ch.ethz.ssh2.channel.ChannelManager;
 import ch.ethz.ssh2.channel.X11ServerData;

 /**
  * A <code>Session</code> is a remote execution of a program. "Program" means
  * in this context either a shell, an application or a system command. The
  * program may or may not have a tty. Only one single program can be started on
  * a session. However, multiple sessions can be active simultaneously.
  *
  * @author Christian Plattner
  * @version $Id: Session.java 32 2011-05-28 21:56:21Z dkocher@sudo.ch $
  */
 public class Session
 {
 	private ChannelManager cm;
 	private Channel cn;

 	private boolean flag_pty_requested = false;
 	private boolean flag_x11_requested = false;
 	private boolean flag_execution_started = false;
 	private boolean flag_closed = false;

 	private String x11FakeCookie = null;

 	private final SecureRandom rnd;

 	protected Session(ChannelManager cm, SecureRandom rnd) throws IOException
 	{
 		this.cm = cm;
 		this.cn = cm.openSessionChannel();
 		this.rnd = rnd;
 	}

 	/**
 	 * Basically just a wrapper for lazy people - identical to calling
 	 * <code>requestPTY("dumb", 0, 0, 0, 0, null)</code>.
 	 *
 	 * @throws IOException
 	 */
 	public void requestDumbPTY() throws IOException
 	{
 		requestPTY("dumb", 0, 0, 0, 0, null);
 	}

 	/**
 	 * Basically just another wrapper for lazy people - identical to calling
 	 * <code>requestPTY(term, 0, 0, 0, 0, null)</code>.
 	 *
 	 * @throws IOException
 	 */
 	public void requestPTY(String term) throws IOException
 	{
 		requestPTY(term, 0, 0, 0, 0, null);
 	}

 	/**
 	 * Allocate a pseudo-terminal for this session.
 	 * <p/>
 	 * This method may only be called before a program or shell is started in
 	 * this session.
 	 * <p/>
 	 * Different aspects can be specified:
 	 * <p/>
 	 * <ul>
 	 * <li>The TERM environment variable value (e.g., vt100)</li>
 	 * <li>The terminal's dimensions.</li>
 	 * <li>The encoded terminal modes.</li>
 	 * </ul>
 	 * Zero dimension parameters are ignored. The character/row dimensions
 	 * override the pixel dimensions (when nonzero). Pixel dimensions refer to
 	 * the drawable area of the window. The dimension parameters are only
 	 * informational. The encoding of terminal modes (parameter
 	 * <code>terminal_modes</code>) is described in RFC4254.
 	 *
 	 * @param term The TERM environment variable value (e.g., vt100)
 	 * @param term_width_characters terminal width, characters (e.g., 80)
 	 * @param term_height_characters terminal height, rows (e.g., 24)
 	 * @param term_width_pixels terminal width, pixels (e.g., 640)
 	 * @param term_height_pixels terminal height, pixels (e.g., 480)
 	 * @param terminal_modes encoded terminal modes (may be <code>null</code>)
 	 * @throws IOException
 	 */
 	public void requestPTY(String term, int term_width_characters, int term_height_characters, int term_width_pixels,
 						   int term_height_pixels, byte[] terminal_modes) throws IOException
 	{
 		if (term == null)
 			throw new IllegalArgumentException("TERM cannot be null.");

 		if ((terminal_modes != null) && (terminal_modes.length > 0))
 		{
 			if (terminal_modes[terminal_modes.length - 1] != 0)
 				throw new IOException("Illegal terminal modes description, does not end in zero byte");
 		}
 		else
 			terminal_modes = new byte[]{0};

 		synchronized (this)
 		{
 			/* The following is just a nicer error, we would catch it anyway later in the channel code */
 			if (flag_closed)
 				throw new IOException("This session is closed.");

 			if (flag_pty_requested)
 				throw new IOException("A PTY was already requested.");

 			if (flag_execution_started)
 				throw new IOException(
 						"Cannot request PTY at this stage anymore, a remote execution has already started.");

 			flag_pty_requested = true;
 		}

 		cm.requestPTY(cn, term, term_width_characters, term_height_characters, term_width_pixels, term_height_pixels,
 				terminal_modes);
 	}

 	/**
 	 * Request X11 forwarding for the current session.
 	 * <p/>
 	 * You have to supply the name and port of your X-server.
 	 * <p/>
 	 * This method may only be called before a program or shell is started in
 	 * this session.
 	 *
 	 * @param hostname the hostname of the real (target) X11 server (e.g., 127.0.0.1)
 	 * @param port the port of the real (target) X11 server (e.g., 6010)
 	 * @param cookie if non-null, then present this cookie to the real X11 server
 	 * @param singleConnection if true, then the server is instructed to only forward one single
 	 * connection, no more connections shall be forwarded after first, or after the session
 	 * channel has been closed
 	 * @throws IOException
 	 */
 	public void requestX11Forwarding(String hostname, int port, byte[] cookie, boolean singleConnection)
 			throws IOException
 	{
 		if (hostname == null)
 			throw new IllegalArgumentException("hostname argument may not be null");

 		synchronized (this)
 		{
 			/* The following is just a nicer error, we would catch it anyway later in the channel code */
 			if (flag_closed)
 				throw new IOException("This session is closed.");

 			if (flag_x11_requested)
 				throw new IOException("X11 forwarding was already requested.");

 			if (flag_execution_started)
 				throw new IOException(
 						"Cannot request X11 forwarding at this stage anymore, a remote execution has already started.");

 			flag_x11_requested = true;
 		}

 		/* X11ServerData - used to store data about the target X11 server */

 		X11ServerData x11data = new X11ServerData();

 		x11data.hostname = hostname;
 		x11data.port = port;
 		x11data.x11_magic_cookie = cookie; /* if non-null, then present this cookie to the real X11 server */

 		/* Generate fake cookie - this one is used between remote clients and the ganymed proxy */

 		byte[] fakeCookie = new byte[16];
 		String hexEncodedFakeCookie;

 		/* Make sure that this fake cookie is unique for this connection */

 		while (true)
 		{
 			rnd.nextBytes(fakeCookie);

 			/* Generate also hex representation of fake cookie */

 			StringBuilder tmp = new StringBuilder(32);
 			for (int i = 0; i < fakeCookie.length; i++)
 			{
 				String digit2 = Integer.toHexString(fakeCookie[i] & 0xff);
 				tmp.append((digit2.length() == 2) ? digit2 : "0" + digit2);
 			}
 			hexEncodedFakeCookie = tmp.toString();

 			/* Well, yes, chances are low, but we want to be on the safe side */

 			if (cm.checkX11Cookie(hexEncodedFakeCookie) == null)
 				break;
 		}

 		/* Ask for X11 forwarding */

 		cm.requestX11(cn, singleConnection, "MIT-MAGIC-COOKIE-1", hexEncodedFakeCookie, 0);

 		/* OK, that went fine, get ready to accept X11 connections... */
 		/* ... but only if the user has not called close() in the meantime =) */

 		synchronized (this)
 		{
 			if (flag_closed == false)
 			{
 				this.x11FakeCookie = hexEncodedFakeCookie;
 				cm.registerX11Cookie(hexEncodedFakeCookie, x11data);
 			}
 		}

 		/* Now it is safe to start remote X11 programs */
 	}

 	/**
 	 * Execute a command on the remote machine.
 	 *
 	 * @param cmd The command to execute on the remote host.
 	 * @throws IOException
 	 */
 	public void execCommand(String cmd) throws IOException
 	{
 		this.execCommand(cmd, null);
 	}

 	/**
 	 * Execute a command on the remote machine.
 	 *
 	 * @param cmd The command to execute on the remote host.
 	 * @param charsetName The charset used to convert between Java Unicode Strings and byte encodings
 	 * @throws IOException
 	 */
 	public void execCommand(String cmd, String charsetName) throws IOException
 	{
 		if (cmd == null)
 			throw new IllegalArgumentException("cmd argument may not be null");

 		synchronized (this)
 		{
 			/* The following is just a nicer error, we would catch it anyway later in the channel code */
 			if (flag_closed)
 				throw new IOException("This session is closed.");

 			if (flag_execution_started)
 				throw new IOException("A remote execution has already started.");

 			flag_execution_started = true;
 		}

 		cm.requestExecCommand(cn, cmd, charsetName);
 	}

 	/**
 	 * Start a shell on the remote machine.
 	 *
 	 * @throws IOException
 	 */
 	public void startShell() throws IOException
 	{
 		synchronized (this)
 		{
 			/* The following is just a nicer error, we would catch it anyway later in the channel code */
 			if (flag_closed)
 				throw new IOException("This session is closed.");

 			if (flag_execution_started)
 				throw new IOException("A remote execution has already started.");

 			flag_execution_started = true;
 		}

 		cm.requestShell(cn);
 	}

 	/**
 	 * Start a subsystem on the remote machine.
 	 * Unless you know what you are doing, you will never need this.
 	 *
 	 * @param name the name of the subsystem.
 	 * @throws IOException
 	 */
 	public void startSubSystem(String name) throws IOException
 	{
 		if (name == null)
 			throw new IllegalArgumentException("name argument may not be null");

 		synchronized (this)
 		{
 			/* The following is just a nicer error, we would catch it anyway later in the channel code */
 			if (flag_closed)
 				throw new IOException("This session is closed.");

 			if (flag_execution_started)
 				throw new IOException("A remote execution has already started.");

 			flag_execution_started = true;
 		}

 		cm.requestSubSystem(cn, name);
 	}

 	public int getState()
 	{
 		return cn.getState();
 	}

 	public InputStream getStdout()
 	{
 		return cn.getStdoutStream();
 	}

 	public InputStream getStderr()
 	{
 		return cn.getStderrStream();
 	}

 	public OutputStream getStdin()
 	{
 		return cn.getStdinStream();
 	}

 	/**
 	 * This method blocks until there is more data available on either the
 	 * stdout or stderr InputStream of this <code>Session</code>. Very useful
 	 * if you do not want to use two parallel threads for reading from the two
 	 * InputStreams. One can also specify a timeout. NOTE: do NOT call this
 	 * method if you use concurrent threads that operate on either of the two
 	 * InputStreams of this <code>Session</code> (otherwise this method may
 	 * block, even though more data is available).
 	 *
 	 * @param timeout The (non-negative) timeout in <code>ms</code>. <code>0</code> means no
 	 * timeout, the call may block forever.
 	 * @return <ul>
 	 *         <li><code>0</code> if no more data will arrive.</li>
 	 *         <li><code>1</code> if more data is available.</li>
 	 *         <li><code>-1</code> if a timeout occurred.</li>
 	 *         </ul>
 	 * @throws IOException
 	 * @deprecated This method has been replaced with a much more powerful wait-for-condition
 	 *             interface and therefore acts only as a wrapper.
 	 */
 	public int waitUntilDataAvailable(long timeout) throws IOException
 	{
 		if (timeout < 0)
 			throw new IllegalArgumentException("timeout must not be negative!");

 		int conditions = cm.waitForCondition(cn, timeout, ChannelCondition.STDOUT_DATA | ChannelCondition.STDERR_DATA
 				| ChannelCondition.EOF);

 		if ((conditions & ChannelCondition.TIMEOUT) != 0)
 			return -1;

 		if ((conditions & (ChannelCondition.STDOUT_DATA | ChannelCondition.STDERR_DATA)) != 0)
 			return 1;

 		/* Here we do not need to check separately for CLOSED, since CLOSED implies EOF */

 		if ((conditions & ChannelCondition.EOF) != 0)
 			return 0;

 		throw new IllegalStateException("Unexpected condition result (" + conditions + ")");
 	}

 	/**
 	 * This method blocks until certain conditions hold true on the underlying SSH-2 channel.
 	 * <p/>
 	 * This method returns as soon as one of the following happens:
 	 * <ul>
 	 * <li>at least of the specified conditions (see {@link ChannelCondition}) holds true</li>
 	 * <li>timeout > 0 and a timeout occured (TIMEOUT will be set in result conditions)</a>
 	 * <li>the underlying channel was closed (CLOSED will be set in result conditions)</a>
 	 * </ul>
 	 * <p/>
 	 * In any case, the result value contains ALL current conditions, which may be more
 	 * than the specified condition set (i.e., never use the "==" operator to test for conditions
 	 * in the bitmask, see also comments in {@link ChannelCondition}).
 	 * <p/>
 	 * Note: do NOT call this method if you want to wait for STDOUT_DATA or STDERR_DATA and
 	 * there are concurrent threads (e.g., StreamGobblers) that operate on either of the two
 	 * InputStreams of this <code>Session</code> (otherwise this method may
 	 * block, even though more data is available in the StreamGobblers).
 	 *
 	 * @param condition_set a bitmask based on {@link ChannelCondition} values
 	 * @param timeout non-negative timeout in ms, <code>0</code> means no timeout
 	 * @return all bitmask specifying all current conditions that are true
 	 */

 	public int waitForCondition(int condition_set, long timeout)
 	{
 		if (timeout < 0)
 			throw new IllegalArgumentException("timeout must be non-negative!");

 		return cm.waitForCondition(cn, timeout, condition_set);
 	}

 	/**
 	 * Get the exit code/status from the remote command - if available. Be
 	 * careful - not all server implementations return this value. It is
 	 * generally a good idea to call this method only when all data from the
 	 * remote side has been consumed (see also the <code<WaitForCondition</code> method).
 	 *
 	 * @return An <code>Integer</code> holding the exit code, or
 	 *         <code>null</code> if no exit code is (yet) available.
 	 */
 	public Integer getExitStatus()
 	{
 		return cn.getExitStatus();
 	}

 	/**
 	 * Get the name of the signal by which the process on the remote side was
 	 * stopped - if available and applicable. Be careful - not all server
 	 * implementations return this value.
 	 *
 	 * @return An <code>String</code> holding the name of the signal, or
 	 *         <code>null</code> if the process exited normally or is still
 	 *         running (or if the server forgot to send this information).
 	 */
 	public String getExitSignal()
 	{
 		return cn.getExitSignal();
 	}

 	/**
 	 * Close this session. NEVER forget to call this method to free up resources -
 	 * even if you got an exception from one of the other methods (or when
 	 * getting an Exception on the Input- or OutputStreams). Sometimes these other
 	 * methods may throw an exception, saying that the underlying channel is
 	 * closed (this can happen, e.g., if the other server sent a close message.)
 	 * However, as long as you have not called the <code>close()</code>
 	 * method, you may be wasting (local) resources.
 	 */
 	public void close()
 	{
 		synchronized (this)
 		{
 			if (flag_closed)
 				return;

 			flag_closed = true;

 			if (x11FakeCookie != null)
 				cm.unRegisterX11Cookie(x11FakeCookie, true);

 			try
 			{
 				cm.closeChannel(cn, "Closed due to user request", true);
 			}
 			catch (IOException ignored)
 			{
 			}
 		}
 	}
 }
	/*
	* Copyright (c) 2006-2011 Christian Plattner. All rights reserved.
	* Please refer to the LICENSE.txt for licensing details.
	*/
	package ch.ethz.ssh2;

	import java.io.IOException;
	import java.io.InputStream;
	import java.io.OutputStream;
	import java.security.SecureRandom;

	import ch.ethz.ssh2.channel.Channel;
	import ch.ethz.ssh2.channel.ChannelManager;
	import ch.ethz.ssh2.channel.X11ServerData;

	/**
	* A <code>Session</code> is a remote execution of a program. "Program" means
	* in this context either a shell, an application or a system command. The
	* program may or may not have a tty. Only one single program can be started on
	* a session. However, multiple sessions can be active simultaneously.
	*
	* @author Christian Plattner
	* @version $Id: Session.java 32 2011-05-28 21:56:21Z dkocher@sudo.ch $
	*/
	public class Session
	{
	private ChannelManager cm;
	private Channel cn;

	private boolean flag_pty_requested = false;
	private boolean flag_x11_requested = false;
	private boolean flag_execution_started = false;
	private boolean flag_closed = false;

	private String x11FakeCookie = null;

	private final SecureRandom rnd;

	protected Session(ChannelManager cm, SecureRandom rnd) throws IOException
	{
	this.cm = cm;
	this.cn = cm.openSessionChannel();
	this.rnd = rnd;
	}

	/**
	* Basically just a wrapper for lazy people - identical to calling
	* <code>requestPTY("dumb", 0, 0, 0, 0, null)</code>.
	*
	* @throws IOException
	*/
	public void requestDumbPTY() throws IOException
	{
	requestPTY("dumb", 0, 0, 0, 0, null);
	}

	/**
	* Basically just another wrapper for lazy people - identical to calling
	* <code>requestPTY(term, 0, 0, 0, 0, null)</code>.
	*
	* @throws IOException
	*/
	public void requestPTY(String term) throws IOException
	{
	requestPTY(term, 0, 0, 0, 0, null);
	}

	/**
	* Allocate a pseudo-terminal for this session.
	* <p/>
	* This method may only be called before a program or shell is started in
	* this session.
	* <p/>
	* Different aspects can be specified:
	* <p/>
	* <ul>
	* <li>The TERM environment variable value (e.g., vt100)</li>
	* <li>The terminal's dimensions.</li>
	* <li>The encoded terminal modes.</li>
	* </ul>
	* Zero dimension parameters are ignored. The character/row dimensions
	* override the pixel dimensions (when nonzero). Pixel dimensions refer to
	* the drawable area of the window. The dimension parameters are only
	* informational. The encoding of terminal modes (parameter
	* <code>terminal_modes</code>) is described in RFC4254.
	*
	* @param term The TERM environment variable value (e.g., vt100)
	* @param term_width_characters terminal width, characters (e.g., 80)
	* @param term_height_characters terminal height, rows (e.g., 24)
	* @param term_width_pixels terminal width, pixels (e.g., 640)
	* @param term_height_pixels terminal height, pixels (e.g., 480)
	* @param terminal_modes encoded terminal modes (may be <code>null</code>)
	* @throws IOException
	*/
	public void requestPTY(String term, int term_width_characters, int term_height_characters, int term_width_pixels,
	int term_height_pixels, byte[] terminal_modes) throws IOException
	{
	if (term == null)
	throw new IllegalArgumentException("TERM cannot be null.");

	if ((terminal_modes != null) && (terminal_modes.length > 0))
	{
	if (terminal_modes[terminal_modes.length - 1] != 0)
	throw new IOException("Illegal terminal modes description, does not end in zero byte");
	}
	else
	terminal_modes = new byte[]{0};

	synchronized (this)
	{
	/* The following is just a nicer error, we would catch it anyway later in the channel code */
	if (flag_closed)
	throw new IOException("This session is closed.");

	if (flag_pty_requested)
	throw new IOException("A PTY was already requested.");

	if (flag_execution_started)
	throw new IOException(
	"Cannot request PTY at this stage anymore, a remote execution has already started.");

	flag_pty_requested = true;
	}

	cm.requestPTY(cn, term, term_width_characters, term_height_characters, term_width_pixels, term_height_pixels,
	terminal_modes);
	}

	/**
	* Request X11 forwarding for the current session.
	* <p/>
	* You have to supply the name and port of your X-server.
	* <p/>
	* This method may only be called before a program or shell is started in
	* this session.
	*
	* @param hostname the hostname of the real (target) X11 server (e.g., 127.0.0.1)
	* @param port the port of the real (target) X11 server (e.g., 6010)
	* @param cookie if non-null, then present this cookie to the real X11 server
	* @param singleConnection if true, then the server is instructed to only forward one single
	* connection, no more connections shall be forwarded after first, or after the session
	* channel has been closed
	* @throws IOException
	*/
	public void requestX11Forwarding(String hostname, int port, byte[] cookie, boolean singleConnection)
	throws IOException
	{
	if (hostname == null)
	throw new IllegalArgumentException("hostname argument may not be null");

	synchronized (this)
	{
	/* The following is just a nicer error, we would catch it anyway later in the channel code */
	if (flag_closed)
	throw new IOException("This session is closed.");

	if (flag_x11_requested)
	throw new IOException("X11 forwarding was already requested.");

	if (flag_execution_started)
	throw new IOException(
	"Cannot request X11 forwarding at this stage anymore, a remote execution has already started.");

	flag_x11_requested = true;
	}

	/* X11ServerData - used to store data about the target X11 server */

	X11ServerData x11data = new X11ServerData();

	x11data.hostname = hostname;
	x11data.port = port;
	x11data.x11_magic_cookie = cookie; /* if non-null, then present this cookie to the real X11 server */

	/* Generate fake cookie - this one is used between remote clients and the ganymed proxy */

	byte[] fakeCookie = new byte[16];
	String hexEncodedFakeCookie;

	/* Make sure that this fake cookie is unique for this connection */

	while (true)
	{
	rnd.nextBytes(fakeCookie);

	/* Generate also hex representation of fake cookie */

	StringBuilder tmp = new StringBuilder(32);
	for (int i = 0; i < fakeCookie.length; i++)
	{
	String digit2 = Integer.toHexString(fakeCookie[i] & 0xff);
	tmp.append((digit2.length() == 2) ? digit2 : "0" + digit2);
	}
	hexEncodedFakeCookie = tmp.toString();

	/* Well, yes, chances are low, but we want to be on the safe side */

	if (cm.checkX11Cookie(hexEncodedFakeCookie) == null)
	break;
	}

	/* Ask for X11 forwarding */

	cm.requestX11(cn, singleConnection, "MIT-MAGIC-COOKIE-1", hexEncodedFakeCookie, 0);

	/* OK, that went fine, get ready to accept X11 connections... */
	/* ... but only if the user has not called close() in the meantime =) */

	synchronized (this)
	{
	if (flag_closed == false)
	{
	this.x11FakeCookie = hexEncodedFakeCookie;
	cm.registerX11Cookie(hexEncodedFakeCookie, x11data);
	}
	}

	/* Now it is safe to start remote X11 programs */
	}

	/**
	* Execute a command on the remote machine.
	*
	* @param cmd The command to execute on the remote host.
	* @throws IOException
	*/
	public void execCommand(String cmd) throws IOException
	{
	this.execCommand(cmd, null);
	}

	/**
	* Execute a command on the remote machine.
	*
	* @param cmd The command to execute on the remote host.
	* @param charsetName The charset used to convert between Java Unicode Strings and byte encodings
	* @throws IOException
	*/
	public void execCommand(String cmd, String charsetName) throws IOException
	{
	if (cmd == null)
	throw new IllegalArgumentException("cmd argument may not be null");

	synchronized (this)
	{
	/* The following is just a nicer error, we would catch it anyway later in the channel code */
	if (flag_closed)
	throw new IOException("This session is closed.");

	if (flag_execution_started)
	throw new IOException("A remote execution has already started.");

	flag_execution_started = true;
	}

	cm.requestExecCommand(cn, cmd, charsetName);
	}

	/**
	* Start a shell on the remote machine.
	*
	* @throws IOException
	*/
	public void startShell() throws IOException
	{
	synchronized (this)
	{
	/* The following is just a nicer error, we would catch it anyway later in the channel code */
	if (flag_closed)
	throw new IOException("This session is closed.");

	if (flag_execution_started)
	throw new IOException("A remote execution has already started.");

	flag_execution_started = true;
	}

	cm.requestShell(cn);
	}

	/**
	* Start a subsystem on the remote machine.
	* Unless you know what you are doing, you will never need this.
	*
	* @param name the name of the subsystem.
	* @throws IOException
	*/
	public void startSubSystem(String name) throws IOException
	{
	if (name == null)
	throw new IllegalArgumentException("name argument may not be null");

	synchronized (this)
	{
	/* The following is just a nicer error, we would catch it anyway later in the channel code */
	if (flag_closed)
	throw new IOException("This session is closed.");

	if (flag_execution_started)
	throw new IOException("A remote execution has already started.");

	flag_execution_started = true;
	}

	cm.requestSubSystem(cn, name);
	}

	public int getState()
	{
	return cn.getState();
	}

	public InputStream getStdout()
	{
	return cn.getStdoutStream();
	}

	public InputStream getStderr()
	{
	return cn.getStderrStream();
	}

	public OutputStream getStdin()
	{
	return cn.getStdinStream();
	}

	/**
	* This method blocks until there is more data available on either the
	* stdout or stderr InputStream of this <code>Session</code>. Very useful
	* if you do not want to use two parallel threads for reading from the two
	* InputStreams. One can also specify a timeout. NOTE: do NOT call this
	* method if you use concurrent threads that operate on either of the two
	* InputStreams of this <code>Session</code> (otherwise this method may
	* block, even though more data is available).
	*
	* @param timeout The (non-negative) timeout in <code>ms</code>. <code>0</code> means no
	* timeout, the call may block forever.
	* @return <ul>
	* <li><code>0</code> if no more data will arrive.</li>
	* <li><code>1</code> if more data is available.</li>
	* <li><code>-1</code> if a timeout occurred.</li>
	* </ul>
	* @throws IOException
	* @deprecated This method has been replaced with a much more powerful wait-for-condition
	* interface and therefore acts only as a wrapper.
	*/
	public int waitUntilDataAvailable(long timeout) throws IOException
	{
	if (timeout < 0)
	throw new IllegalArgumentException("timeout must not be negative!");

	int conditions = cm.waitForCondition(cn, timeout, ChannelCondition.STDOUT_DATA \| ChannelCondition.STDERR_DATA
	\| ChannelCondition.EOF);

	if ((conditions & ChannelCondition.TIMEOUT) != 0)
	return -1;

	if ((conditions & (ChannelCondition.STDOUT_DATA \| ChannelCondition.STDERR_DATA)) != 0)
	return 1;

	/* Here we do not need to check separately for CLOSED, since CLOSED implies EOF */

	if ((conditions & ChannelCondition.EOF) != 0)
	return 0;

	throw new IllegalStateException("Unexpected condition result (" + conditions + ")");
	}

	/**
	* This method blocks until certain conditions hold true on the underlying SSH-2 channel.
	* <p/>
	* This method returns as soon as one of the following happens:
	* <ul>
	* <li>at least of the specified conditions (see {@link ChannelCondition}) holds true</li>
	* <li>timeout > 0 and a timeout occured (TIMEOUT will be set in result conditions)</a>
	* <li>the underlying channel was closed (CLOSED will be set in result conditions)</a>
	* </ul>
	* <p/>
	* In any case, the result value contains ALL current conditions, which may be more
	* than the specified condition set (i.e., never use the "==" operator to test for conditions
	* in the bitmask, see also comments in {@link ChannelCondition}).
	* <p/>
	* Note: do NOT call this method if you want to wait for STDOUT_DATA or STDERR_DATA and
	* there are concurrent threads (e.g., StreamGobblers) that operate on either of the two
	* InputStreams of this <code>Session</code> (otherwise this method may
	* block, even though more data is available in the StreamGobblers).
	*
	* @param condition_set a bitmask based on {@link ChannelCondition} values
	* @param timeout non-negative timeout in ms, <code>0</code> means no timeout
	* @return all bitmask specifying all current conditions that are true
	*/

	public int waitForCondition(int condition_set, long timeout)
	{
	if (timeout < 0)
	throw new IllegalArgumentException("timeout must be non-negative!");

	return cm.waitForCondition(cn, timeout, condition_set);
	}

	/**
	* Get the exit code/status from the remote command - if available. Be
	* careful - not all server implementations return this value. It is
	* generally a good idea to call this method only when all data from the
	* remote side has been consumed (see also the <code<WaitForCondition</code> method).
	*
	* @return An <code>Integer</code> holding the exit code, or
	* <code>null</code> if no exit code is (yet) available.
	*/
	public Integer getExitStatus()
	{
	return cn.getExitStatus();
	}

	/**
	* Get the name of the signal by which the process on the remote side was
	* stopped - if available and applicable. Be careful - not all server
	* implementations return this value.
	*
	* @return An <code>String</code> holding the name of the signal, or
	* <code>null</code> if the process exited normally or is still
	* running (or if the server forgot to send this information).
	*/
	public String getExitSignal()
	{
	return cn.getExitSignal();
	}

	/**
	* Close this session. NEVER forget to call this method to free up resources -
	* even if you got an exception from one of the other methods (or when
	* getting an Exception on the Input- or OutputStreams). Sometimes these other
	* methods may throw an exception, saying that the underlying channel is
	* closed (this can happen, e.g., if the other server sent a close message.)
	* However, as long as you have not called the <code>close()</code>
	* method, you may be wasting (local) resources.
	*/
	public void close()
	{
	synchronized (this)
	{
	if (flag_closed)
	return;

	flag_closed = true;

	if (x11FakeCookie != null)
	cm.unRegisterX11Cookie(x11FakeCookie, true);

	try
	{
	cm.closeChannel(cn, "Closed due to user request", true);
	}
	catch (IOException ignored)
	{
	}
	}
	}
	}