chamilo-lms/main/app_share/VncViewer.java

//  Copyright (C) 2002-2005 Ultr@VNC Team.  All Rights Reserved.
//  Copyright (C) 2004 Kenn Min Chong, John Witchel.  All Rights Reserved.
//  Copyright (C) 2004 Alban Chazot.  All Rights Reserved.
//  Copyright (C) 2001,2002 HorizonLive.com, Inc.  All Rights Reserved.
//  Copyright (C) 2002 Constantin Kaplinsky.  All Rights Reserved.
//  Copyright (C) 1999 AT&T Laboratories Cambridge.  All Rights Reserved.
//
//  This is free software; you can redistribute it and/or modify
//  it under the terms of the GNU General Public License as published by
//  the Free Software Foundation; either version 2 of the License, or
//  (at your option) any later version.
//
//  This software is distributed in the hope that it will be useful,
//  but WITHOUT ANY WARRANTY; without even the implied warranty of
//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//  GNU General Public License for more details.
//
//  You should have received a copy of the GNU General Public License
//  along with this software; if not, write to the Free Software
//  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307,
//  USA.
//

//
// VncViewer.java - the VNC viewer applet.  This class mainly just sets up the
// user interface, leaving it to the VncCanvas to do the actual rendering of
// a VNC desktop.
//

// Alban Chazot - Carmi Grenoble July 5th 2004 
// * Add support for Ultr@VNC mslogon feature.
//   You can now be connected to a Ultr@VNC box with mslogon required.
//   Thanks to Wim Vandersmissen, who provide a TightVNC viewer patch do to so.
//   That give me the idea to provide it in the java viewer too.
//
// * Add ScrollPanel to applet mode
//
import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.net.*;
import javax.swing.*;

public class VncViewer extends java.applet.Applet implements java.lang.Runnable, WindowListener {

	boolean inAnApplet = true;

	boolean inSeparateFrame = false;

	// mslogon support

	boolean mslogon = false;

	// mslogon support end

	//
	// main() is called when run as a java program from the command line.
	// It simply runs the applet inside a newly-created frame.
	//

	public static void main(String[] argv) {
		VncViewer v = new VncViewer();
		v.mainArgs = argv;
		v.inAnApplet = false;
		v.inSeparateFrame = true;

		v.init();
		v.start();
	}

	String[] mainArgs;

	RfbProto rfb;

	Thread rfbThread;

	Frame vncFrame;

	Container vncContainer;

	ScrollPane desktopScrollPane;

	GridBagLayout gridbag;

	ButtonPanel buttonPanel;

	//AuthPanel authenticator;

	VncCanvas vc;

	OptionsFrame options;

	ClipboardFrame clipboard;

	RecordingFrame rec;

	FTPFrame ftp; // KMC: FTP Frame declaration

	// Control session recording.
	Object recordingSync;

	String sessionFileName;

	boolean recordingActive;

	boolean recordingStatusChanged;

	String cursorUpdatesDef;

	String eightBitColorsDef;

	// Variables read from parameter values.
	String host;

	int port;

	String passwordParam;

	String encPasswordParam;

	boolean showControls;

	boolean showOfflineDesktop;

	int deferScreenUpdates;

	int deferCursorUpdates;

	int deferUpdateRequests;
	
	String serverID;

	// mslogon support 2
	String usernameParam;

	String encUsernameParam;

	String dm;

	byte[] domain = new byte[256];

	byte[] user = new byte[256];

	byte[] passwd = new byte[32];

	int i;

	// mslogon support 2 end

	//
	// init()
	//

	public void init() {

		readParameters();

		if (inSeparateFrame) {
			vncFrame = new Frame("Ultr@VNC");
			if (!inAnApplet) {
				vncFrame.add("Center", this);
			}
			vncContainer = vncFrame;
		} else {
			vncContainer = this;
		}

		recordingSync = new Object();

		options = new OptionsFrame(this);
		clipboard = new ClipboardFrame(this);
		// authenticator = new AuthPanel(false); // mslogon support : go to connectAndAuthenticate()
		if (RecordingFrame.checkSecurity())
			rec = new RecordingFrame(this);

		sessionFileName = null;
		recordingActive = false;
		recordingStatusChanged = false;
		cursorUpdatesDef = null;
		eightBitColorsDef = null;

		if (inSeparateFrame)
			vncFrame.addWindowListener(this);

		ftp = new FTPFrame(this); // KMC: FTPFrame creation
		rfbThread = new Thread(this);
		rfbThread.start();
	}

	public void update(Graphics g) {
	}

	//
	// run() - executed by the rfbThread to deal with the RFB socket.
	//

	public void run() {

		gridbag = new GridBagLayout();
		vncContainer.setLayout(gridbag);

		GridBagConstraints gbc = new GridBagConstraints();
		gbc.gridwidth = GridBagConstraints.REMAINDER;
		gbc.anchor = GridBagConstraints.NORTHWEST;

		// modif appshare pvandermaesen@noctis.be, never show control
		/*
		if (showControls) {
			buttonPanel = new ButtonPanel(this);
			gridbag.setConstraints(buttonPanel, gbc);
 			vncContainer.add(buttonPanel);
		}
		*/

		try {
			connectAndAuthenticate();

			doProtocolInitialisation();

			vc = new VncCanvas(this);
			gbc.weightx = 1.0;
			gbc.weighty = 1.0;

			// Add ScrollPanel to applet mode

			// Create a panel which itself is resizeable and can hold
			// non-resizeable VncCanvas component at the top left corner.
			Panel canvasPanel = new Panel();
			canvasPanel.setLayout(new FlowLayout(FlowLayout.LEFT, 0, 0));
			canvasPanel.add(vc);

			// Create a ScrollPane which will hold a panel with VncCanvas
			// inside.
			desktopScrollPane = new ScrollPane(ScrollPane.SCROLLBARS_AS_NEEDED);
			gbc.fill = GridBagConstraints.BOTH;
			gridbag.setConstraints(desktopScrollPane, gbc);
			desktopScrollPane.add(canvasPanel);

			if (inSeparateFrame) {
				// Finally, add our ScrollPane to the Frame window.
				vncFrame.add(desktopScrollPane);
				vncFrame.setTitle(rfb.desktopName);
				vncFrame.pack();
				vc.resizeDesktopFrame();
			} else {
				// Finally, add the scrollable panel component to the Applet.
				gridbag.setConstraints(desktopScrollPane, gbc);
				add(desktopScrollPane);

				// Add ScrollPanel to applet mode end

				validate();

			}

			moveFocusToDesktop();
			
			
			vc.processNormalProtocol();

		} catch (NoRouteToHostException e) {
			e.printStackTrace();
			fatalError("Network error: no route to server: " + host);
		} catch (UnknownHostException e) {
			e.printStackTrace();
			fatalError("Network error: server name unknown: " + host);
		} catch (ConnectException e) {
			e.printStackTrace();
			fatalError("Network error: could not connect to server: " + host + ":" + port);
		} catch (EOFException e) {
			e.printStackTrace();
			if (showOfflineDesktop) {
				System.out.println("Network error: remote side closed connection");
				if (vc != null) {
					vc.enableInput(false);
				}
				if (inSeparateFrame) {
					vncFrame.setTitle(rfb.desktopName + " [disconnected]");
				}
				if (rfb != null) {
					rfb.close();
					rfb = null;
				}
				if (showControls && buttonPanel != null) {
					buttonPanel.disableButtonsOnDisconnect();
					if (inSeparateFrame) {
						vncFrame.pack();
					} else {
						validate();
					}
				}
			} else {
				fatalError("Network error: remote side closed connection");
			}
		} catch (IOException e) {
			String str = e.getMessage();
			e.printStackTrace();
			if (str != null && str.length() != 0) {
				fatalError("Network Error: " + str);
			} else {
				fatalError(e.toString());
			}
		} catch (Exception e) {
			String str = e.getMessage();
			e.printStackTrace();
			if (str != null && str.length() != 0) {
				fatalError("Error: " + str);
			} else {
				fatalError(e.toString());
			}
		}

	}

	//
	// Connect to the RFB server and authenticate the user.
	//

	void connectAndAuthenticate() throws Exception {

		// If "ENCPASSWORD" parameter is set, decrypt the password into
		// the passwordParam string.

		if (encPasswordParam != null) {
			// ENCPASSWORD is hexascii-encoded. Decode.
			byte[] pw = { 0, 0, 0, 0, 0, 0, 0, 0 };
			int len = encPasswordParam.length() / 2;
			if (len > 8)
				len = 8;
			for (int i = 0; i < len; i++) {
				String hex = encPasswordParam.substring(i * 2, i * 2 + 2);
				Integer x = new Integer(Integer.parseInt(hex, 16));
				pw[i] = x.byteValue();
			}

			// Decrypt the password.
			byte[] key = { 23, 82, 107, 6, 35, 78, 88, 7 };
			DesCipher des = new DesCipher(key);
			des.decrypt(pw, 0, pw, 0);
			passwordParam = new String(pw);
		}

		// If a password parameter ("PASSWORD" or "ENCPASSWORD") is set,
		// don't ask user a password, get one from passwordParam instead.
		// Authentication failures would be fatal.

		if (passwordParam != null) {
			
			if (inSeparateFrame) {
				vncFrame.pack();
				vncFrame.show();
			} else {
				validate();
			}
			
			/* modif for autologin for dokeos appshare (noctis) */
			
			
			/* end modif */
			
			if (!tryAuthenticate(usernameParam, passwordParam)) {
				throw new Exception("VNC authentication failed");
			}
			return;
		}

		// There is no "PASSWORD" or "ENCPASSWORD" parameters -- ask user
		// for a password, try to authenticate, retry on authentication
		// failures.

		// mslogon support
		//
		// Detect Auth Protocol (Ultr@VNC or the standard One)
		// To know if we must show the username box
		//

		prologueDetectAuthProtocol();

		//authenticator = new AuthPanel(mslogon);

		// mslogon support end

		GridBagConstraints gbc = new GridBagConstraints();
		gbc.gridwidth = GridBagConstraints.REMAINDER;
		gbc.anchor = GridBagConstraints.NORTHWEST;
		gbc.weightx = 1.0;
		gbc.weighty = 1.0;
		gbc.ipadx = 100;
		gbc.ipady = 50;

		//gridbag.setConstraints(authenticator, gbc);
		//vncContainer.add(authenticator);

		if (inSeparateFrame) {
			vncFrame.pack();
			vncFrame.show();
		} else {
			validate();
			// FIXME: here moveFocusToPasswordField() does not always work
			// under Netscape 4.7x/Java 1.1.5/Linux. It seems like this call
			// is being executed before the password field of the
			// authenticator is fully drawn and activated, therefore
			// requestFocus() does not work. Currently, I don't know how to
			// solve this problem.
			// -- const

			// mslogon support
			//authenticator.moveFocusToUsernameField();
			// mslogon support end
		}

		while (true) {
			// Wait for user entering a password, or a username and a password

//			 Try to authenticate with a given password.
			// mslogon support
			String us="";
			if (mslogon) {
				//us = authenticator.username.getText();
			} else {
				us = "";
			}
			
			/* add for dokeos appShare (noctis) */
			if (tryAuthenticate(us, "dokeos"))
				break;
			
			

		}

		
	}

	// mslogon support
	//
	// Detect Server rfb Protocol to know the auth Method
	// Perform a connexion to detect the Serverminor
	//

	void prologueDetectAuthProtocol() throws Exception {

		rfb = new RfbProto(host, port, this, serverID);

		rfb.readVersionMsg();

		System.out.println("RFB server supports protocol version " + rfb.serverMajor + "." + rfb.serverMinor);

		// Mslogon support
		if (rfb.serverMinor == 4) {
			mslogon = true;
			System.out.println("Ultr@VNC mslogon detected");
		}

		rfb.writeVersionMsg();

	}

	// mslogon support end

	//
	// Try to authenticate with a given password.
	//

	boolean tryAuthenticate(String us, String pw) throws Exception {

		rfb = new RfbProto(host, port, this, serverID);

		rfb.readVersionMsg();

		System.out.println("RFB server supports protocol version " + rfb.serverMajor + "." + rfb.serverMinor);

		rfb.writeVersionMsg();

		int authScheme = rfb.readAuthScheme();

		switch (authScheme) {

		case RfbProto.NoAuth:
			System.out.println("No authentication needed");
			return true;

		case RfbProto.VncAuth:

			if (mslogon) {
				System.out.println("showing JOptionPane warning.");
				int n = JOptionPane.showConfirmDialog(vncFrame, "The current authentication method does not transfer your password securely." + "Do you want to continue?", "Warning",
						JOptionPane.YES_NO_OPTION);
				if (n != JOptionPane.YES_OPTION) {
					throw new Exception("User cancelled insecure MS-Logon");
				}
			}
			// mslogon support
			byte[] challengems = new byte[64];
			if (mslogon) {
				// copy the us (user) parameter into the user Byte formated variable
				System.arraycopy(us.getBytes(), 0, user, 0, us.length());
				// and pad it with Null
				if (us.length() < 256) {
					for (i = us.length(); i < 256; i++) {
						user[i] = 0;
					}
				}

				dm = ".";
				// copy the dm (domain) parameter into the domain Byte formated variable
				System.arraycopy(dm.getBytes(), 0, domain, 0, dm.length());
				// and pad it with Null
				if (dm.length() < 256) {
					for (i = dm.length(); i < 256; i++) {
						domain[i] = 0;
					}
				}

				// equivalent of vncEncryptPasswdMS

				// copy the pw (password) parameter into the password Byte formated variable
				System.arraycopy(pw.getBytes(), 0, passwd, 0, pw.length());
				// and pad it with Null
				if (pw.length() < 32) {
					for (i = pw.length(); i < 32; i++) {
						passwd[i] = 0;
					}
				}

				// Encrypt the full given password
				byte[] fixedkey = { 23, 82, 107, 6, 35, 78, 88, 7 };
				DesCipher desme = new DesCipher(fixedkey);
				desme.encrypt(passwd, 0, passwd, 0);

				// end equivalent of vncEncryptPasswdMS

				// get the mslogon Challenge from server
				rfb.is.readFully(challengems);
			}
			// mslogon support end

			byte[] challenge = new byte[16];
			rfb.is.readFully(challenge);

			if (pw.length() > 8)
				pw = pw.substring(0, 8); // Truncate to 8 chars

			// vncEncryptBytes in the UNIX libvncauth truncates password
			// after the first zero byte. We do to.
			int firstZero = pw.indexOf(0);
			if (firstZero != -1)
				pw = pw.substring(0, firstZero);

			// mslogon support
			if (mslogon) {
				for (i = 0; i < 32; i++) {
					challengems[i] = (byte) (passwd[i] ^ challengems[i]);
				}
				rfb.os.write(user);
				rfb.os.write(domain);
				rfb.os.write(challengems);
			}
			// mslogon support end

			byte[] key = { 0, 0, 0, 0, 0, 0, 0, 0 };
			System.arraycopy(pw.getBytes(), 0, key, 0, pw.length());

			DesCipher des = new DesCipher(key);

			des.encrypt(challenge, 0, challenge, 0);
			des.encrypt(challenge, 8, challenge, 8);

			rfb.os.write(challenge);

			int authResult = rfb.is.readInt();

			switch (authResult) {
			case RfbProto.VncAuthOK:
				System.out.println("VNC authentication succeeded");
				return true;
			case RfbProto.VncAuthFailed:
				System.out.println("VNC authentication failed");
				break;
			case RfbProto.VncAuthTooMany:
				throw new Exception("VNC authentication failed - too many tries");
			default:
				throw new Exception("Unknown VNC authentication result " + authResult);
			}
			break;

		case RfbProto.MsLogon:
			System.out.println("MS-Logon (DH) detected");
			if (AuthMsLogon(us, pw)) {
				return true;
			}
			break;
		default:
			throw new Exception("Unknown VNC authentication scheme " + authScheme);
		}
		return false;
	}

	// marscha@2006: Try to better hide the windows password.
	// I know that this is no breakthrough in modern cryptography.
	// It's just a patch/kludge/workaround.
	boolean AuthMsLogon(String us, String pw) throws Exception {
		byte user[] = new byte[256];
		byte passwd[] = new byte[64];

		long gen = rfb.is.readLong();
		long mod = rfb.is.readLong();
		long resp = rfb.is.readLong();

		DH dh = new DH(gen, mod);
		long pub = dh.createInterKey();

		rfb.os.write(DH.longToBytes(pub));

		long key = dh.createEncryptionKey(resp);
		System.out.println("gen=" + gen + ", mod=" + mod + ", pub=" + pub + ", key=" + key);

		DesCipher des = new DesCipher(DH.longToBytes(key));

		System.arraycopy(us.getBytes(), 0, user, 0, us.length());
		// and pad it with Null
		if (us.length() < 256) {
			for (i = us.length(); i < 256; i++) {
				user[i] = 0;
			}
		}

		// copy the pw (password) parameter into the password Byte formated variable
		System.arraycopy(pw.getBytes(), 0, passwd, 0, pw.length());
		// and pad it with Null
		if (pw.length() < 32) {
			for (i = pw.length(); i < 32; i++) {
				passwd[i] = 0;
			}
		}

		// user = domain + "\\" + user;

		des.encryptText(user, user, DH.longToBytes(key));
		des.encryptText(passwd, passwd, DH.longToBytes(key));

		rfb.os.write(user);
		rfb.os.write(passwd);

		int authResult = rfb.is.readInt();

		switch (authResult) {
		case RfbProto.VncAuthOK:
			System.out.println("MS-Logon (DH) authentication succeeded");
			return true;
		case RfbProto.VncAuthFailed:
			System.out.println("MS-Logon (DH) authentication failed");
			break;
		case RfbProto.VncAuthTooMany:
			throw new Exception("MS-Logon (DH) authentication failed - too many tries");
		default:
			throw new Exception("Unknown MS-Logon (DH) authentication result " + authResult);
		}
		return false;
	}

	//
	// Do the rest of the protocol initialisation.
	//

	void doProtocolInitialisation() throws IOException {

		rfb.writeClientInit();

		rfb.readServerInit();

		System.out.println("Desktop name is " + rfb.desktopName);
		System.out.println("Desktop size is " + rfb.framebufferWidth + " x " + rfb.framebufferHeight);

		setEncodings();
	}

	//
	// Send current encoding list to the RFB server.
	//

	void setEncodings() {
		try {
			if (rfb != null && rfb.inNormalProtocol) {
				rfb.writeSetEncodings(options.encodings, options.nEncodings);
				if (vc != null) {
					vc.softCursorFree();
				}
			}
		} catch (Exception e) {
			e.printStackTrace();
		}
	}

	//
	// setCutText() - send the given cut text to the RFB server.
	//

	void setCutText(String text) {
		try {
			if (rfb != null && rfb.inNormalProtocol) {
				rfb.writeClientCutText(text);
			}
		} catch (Exception e) {
			e.printStackTrace();
		}
	}

	//
	// Order change in session recording status. To stop recording, pass
	// null in place of the fname argument.
	//

	void setRecordingStatus(String fname) {
		synchronized (recordingSync) {
			sessionFileName = fname;
			recordingStatusChanged = true;
		}
	}

	//
	// Start or stop session recording. Returns true if this method call
	// causes recording of a new session.
	//

	boolean checkRecordingStatus() throws IOException {
		synchronized (recordingSync) {
			if (recordingStatusChanged) {
				recordingStatusChanged = false;
				if (sessionFileName != null) {
					startRecording();
					return true;
				} else {
					stopRecording();
				}
			}
		}
		return false;
	}

	//
	// Start session recording.
	//

	protected void startRecording() throws IOException {
		synchronized (recordingSync) {
			if (!recordingActive) {
				// Save settings to restore them after recording the session.
				cursorUpdatesDef = options.choices[options.cursorUpdatesIndex].getSelectedItem();
				eightBitColorsDef = options.choices[options.eightBitColorsIndex].getSelectedItem();
				// Set options to values suitable for recording.
				options.choices[options.cursorUpdatesIndex].select("Disable");
				options.choices[options.cursorUpdatesIndex].setEnabled(false);
				options.setEncodings();
				options.choices[options.eightBitColorsIndex].select("Full");
				options.choices[options.eightBitColorsIndex].setEnabled(false);
				options.setColorFormat();
			} else {
				rfb.closeSession();
			}

			System.out.println("Recording the session in " + sessionFileName);
			rfb.startSession(sessionFileName);
			recordingActive = true;
		}
	}

	//
	// Stop session recording.
	//

	protected void stopRecording() throws IOException {
		synchronized (recordingSync) {
			if (recordingActive) {
				// Restore options.
				options.choices[options.cursorUpdatesIndex].select(cursorUpdatesDef);
				options.choices[options.cursorUpdatesIndex].setEnabled(true);
				options.setEncodings();
				options.choices[options.eightBitColorsIndex].select(eightBitColorsDef);
				options.choices[options.eightBitColorsIndex].setEnabled(true);
				options.setColorFormat();

				rfb.closeSession();
				System.out.println("Session recording stopped.");
			}
			sessionFileName = null;
			recordingActive = false;
		}
	}

	//
	// readParameters() - read parameters from the html source or from the
	// command line. On the command line, the arguments are just a sequence of
	// param_name/param_value pairs where the names and values correspond to
	// those expected in the html applet tag source.
	//

	public void readParameters() {
		host = readParameter("HOST", !inAnApplet);
		if (host == null) {
			host = getCodeBase().getHost();
			if (host.equals("")) {
				fatalError("HOST parameter not specified");
			}
		}
		
		serverID = readParameter("SERVERID", true);

		String str = readParameter("PORT", true);
		port = Integer.parseInt(str);

		if (inAnApplet) {
			str = readParameter("Open New Window", false);
			if (str != null && str.equalsIgnoreCase("Yes"))
				inSeparateFrame = true;
		}

		encPasswordParam = readParameter("ENCPASSWORD", false);
		if (encPasswordParam == null)
			passwordParam = readParameter("PASSWORD", false);

		// "Show Controls" set to "No" disables button panel.
		showControls = true;
		str = readParameter("Show Controls", false);
		if (str != null && str.equalsIgnoreCase("No"))
			showControls = false;

		// Do we continue showing desktop on remote disconnect?
		showOfflineDesktop = false;
		str = readParameter("Show Offline Desktop", false);
		if (str != null && str.equalsIgnoreCase("Yes"))
			showOfflineDesktop = true;

		// Fine tuning options.
		deferScreenUpdates = readIntParameter("Defer screen updates", 20);
		deferCursorUpdates = readIntParameter("Defer cursor updates", 10);
		deferUpdateRequests = readIntParameter("Defer update requests", 50);
	}

	public String readParameter(String name, boolean required) {
		if (inAnApplet) {
			String s = getParameter(name);
			if ((s == null) && required) {
				fatalError(name + " parameter not specified");
			}
			return s;
		}

		for (int i = 0; i < mainArgs.length; i += 2) {
			if (mainArgs[i].equalsIgnoreCase(name)) {
				try {
					return mainArgs[i + 1];
				} catch (Exception e) {
					if (required) {
						fatalError(name + " parameter not specified");
					}
					return null;
				}
			}
		}
		if (required) {
			fatalError(name + " parameter not specified");
		}
		return null;
	}

	int readIntParameter(String name, int defaultValue) {
		String str = readParameter(name, false);
		int result = defaultValue;
		if (str != null) {
			try {
				result = Integer.parseInt(str);
			} catch (NumberFormatException e) {
			}
		}
		return result;
	}

	//
	// moveFocusToDesktop() - move keyboard focus either to the
	// VncCanvas or to the AuthPanel.
	//

	void moveFocusToDesktop() {
		if (vncContainer != null) {
			if (vc != null && vncContainer.isAncestorOf(vc)) {
				vc.requestFocus();
			} 
		}
	}

	//
	// disconnect() - close connection to server.
	//

	boolean disconnectRequested = false;

	synchronized public void disconnect() {
		disconnectRequested = true;
		if (rfb != null) {
			rfb.close();
			rfb = null;
		}
		System.out.println("Disconnect");
		options.dispose();
		clipboard.dispose();
		if (rec != null)
			rec.dispose();

		if (inAnApplet) {
			vncContainer.removeAll();
			Label errLabel = new Label("Disconnected");
			errLabel.setFont(new Font("Helvetica", Font.PLAIN, 12));
			vncContainer.setLayout(new FlowLayout(FlowLayout.LEFT, 30, 30));
			vncContainer.add(errLabel);
			if (inSeparateFrame) {
				vncFrame.pack();
			} else {
				validate();
			}
			rfbThread.stop();
		} else {
			System.exit(0);
		}
	}

	//
	// fatalError() - print out a fatal error message.
	//

	synchronized public void fatalError(String str) {
		if (rfb != null) {
			rfb.close();
			rfb = null;
		}
		System.out.println(str);

		if (disconnectRequested) {
			// Not necessary to show error message if the error was caused
			// by I/O problems after the disconnect() method call.
			disconnectRequested = false;
			return;
		}

		if (inAnApplet) {
			vncContainer.removeAll();
			Label errLabel = new Label(str);
			errLabel.setFont(new Font("Helvetica", Font.PLAIN, 12));
			vncContainer.setLayout(new FlowLayout(FlowLayout.LEFT, 30, 30));
			vncContainer.add(errLabel);
			if (inSeparateFrame) {
				vncFrame.pack();
			} else {
				validate();
			}
			Thread.currentThread().stop();
		} else {
			System.exit(1);
		}
	}

	//
	// This method is called before the applet is destroyed.
	//

	public void destroy() {
		vncContainer.removeAll();
		options.dispose();
		clipboard.dispose();
		if (ftp != null)
			ftp.dispose();
		if (rec != null)
			rec.dispose();
		if (rfb != null)
			rfb.close();
		if (inSeparateFrame)
			vncFrame.dispose();
	}

	//
	// Close application properly on window close event.
	//

	public void windowClosing(WindowEvent evt) {
		if (rfb != null)
			disconnect();

		vncFrame.dispose();
		if (!inAnApplet) {
			System.exit(0);
		}
	}

	//
	// Move the keyboard focus to the password field on window activation.
	//

	public void windowActivated(WindowEvent evt) {
	}

	//
	// Ignore window events we're not interested in.
	//

	public void windowDeactivated(WindowEvent evt) {
	}

	public void windowOpened(WindowEvent evt) {
	}

	public void windowClosed(WindowEvent evt) {
	}

	public void windowIconified(WindowEvent evt) {
	}

	public void windowDeiconified(WindowEvent evt) {
	}
}