510Connectbot: src/com/trilead/ssh2/Session.java comparison

comparison src/com/trilead/ssh2/Session.java @ 0:0ce5cc452d02

initial version

author	Carl Byington <carl@five-ten-sg.com>
date	Thu, 22 May 2014 10:41:19 -0700
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--1:000000000000
+:0ce5cc452d02
+package com.trilead.ssh2;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.security.SecureRandom;
+import com.trilead.ssh2.channel.Channel;
+import com.trilead.ssh2.channel.ChannelManager;
+import com.trilead.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, plattner@trilead.com
+* @version $Id: Session.java,v 1.2 2008/03/03 07:01:36 cplattne Exp $
+*/
+public class Session {
+ChannelManager cm;
+Channel cn;
+boolean flag_pty_requested = false;
+boolean flag_x11_requested = false;
+boolean flag_execution_started = false;
+boolean flag_closed = false;
+String x11FakeCookie = null;
+final SecureRandom rnd;
+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);
+}
+/**
+* Inform other side of connection that our PTY has resized.
+* <p>
+* 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.
+*
+* @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 resizePTY(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.");
+}
+cm.resizePTY(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 our 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 */
+StringBuffer tmp = new StringBuffer(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 {
+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);
+}
+/**
+* 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);
+}
+/**
+* This method can be used to perform end-to-end session (i.e., SSH channel)
+* testing. It sends a 'ping' message to the server and waits for the 'pong'
+* from the server.
+* <p>
+* Implementation details: this method sends a SSH_MSG_CHANNEL_REQUEST request
+* ('trilead-ping') to the server and waits for the SSH_MSG_CHANNEL_FAILURE reply
+* packet.
+*
+* @throws IOException in case of any problem or when the session is closed
+*/
+public void ping() 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.");
+}
+cm.requestChannelTrileadPing(cn);
+}
+/**
+* Request authentication agent forwarding.
+* @param agent object that implements the callbacks
+*
+* @throws IOException in case of any problem or when the session is closed
+*/
+public synchronized boolean requestAuthAgentForwarding(AuthAgentCallback agent) 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.");
+}
+return cm.requestChannelAgentForwarding(cn, agent);
+}
+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) {
+}
+}
+}
+}

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comparison src/com/trilead/ssh2/Session.java @ 0:0ce5cc452d02