--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/ch/ethz/ssh2/Session.java	Fri Jul 18 11:21:46 2014 -0700
@@ -0,0 +1,490 @@
+/*
+ * 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 96 2014-04-08 15:14:37Z 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);
+	}
+
+    /**
+     * Tells the server that the size of the terminal has changed.
+     *
+     * See {@link #requestPTY(String, int, int, int, int, byte[])} for more details about how parameters are interpreted.
+   	 *
+   	 * @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)
+   	 * @throws IOException
+   	 */
+   	public void requestWindowChange(int term_width_characters, int term_height_characters, int term_width_pixels,
+   			int term_height_pixels) 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_pty_requested)
+   				throw new IOException("A PTY was not requested.");
+   		}
+
+   		cm.requestWindowChange(cn, term_width_characters, term_height_characters, term_width_pixels, term_height_pixels);
+   	}
+
+	/**
+	 * 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) throws IOException {
+		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)
+			{
+			}
+		}
+	}
+}