comparison app/src/main/java/ch/ethz/ssh2/Session.java @ 438:d29cce60f393

migrate from Eclipse to Android Studio
author Carl Byington <carl@five-ten-sg.com>
date Thu, 03 Dec 2015 11:23:55 -0800
parents src/ch/ethz/ssh2/Session.java@071eccdff8ea
children
comparison
equal deleted inserted replaced
437:208b31032318 438:d29cce60f393
1 /*
2 * Copyright (c) 2006-2011 Christian Plattner. All rights reserved.
3 * Please refer to the LICENSE.txt for licensing details.
4 */
5 package ch.ethz.ssh2;
6
7 import java.io.IOException;
8 import java.io.InputStream;
9 import java.io.OutputStream;
10 import java.security.SecureRandom;
11
12 import ch.ethz.ssh2.channel.Channel;
13 import ch.ethz.ssh2.channel.ChannelManager;
14 import ch.ethz.ssh2.channel.X11ServerData;
15
16 /**
17 * A <code>Session</code> is a remote execution of a program. "Program" means
18 * in this context either a shell, an application or a system command. The
19 * program may or may not have a tty. Only one single program can be started on
20 * a session. However, multiple sessions can be active simultaneously.
21 *
22 * @author Christian Plattner
23 * @version $Id: Session.java 96 2014-04-08 15:14:37Z dkocher@sudo.ch $
24 */
25 public class Session {
26 private ChannelManager cm;
27 private Channel cn;
28
29 private boolean flag_pty_requested = false;
30 private boolean flag_x11_requested = false;
31 private boolean flag_execution_started = false;
32 private boolean flag_closed = false;
33
34 private String x11FakeCookie = null;
35
36 private final SecureRandom rnd;
37
38 protected Session(ChannelManager cm, SecureRandom rnd) throws IOException {
39 this.cm = cm;
40 this.cn = cm.openSessionChannel();
41 this.rnd = rnd;
42 }
43
44 /**
45 * Basically just a wrapper for lazy people - identical to calling
46 * <code>requestPTY("dumb", 0, 0, 0, 0, null)</code>.
47 *
48 * @throws IOException
49 */
50 public void requestDumbPTY() throws IOException {
51 requestPTY("dumb", 0, 0, 0, 0, null);
52 }
53
54 /**
55 * Basically just another wrapper for lazy people - identical to calling
56 * <code>requestPTY(term, 0, 0, 0, 0, null)</code>.
57 *
58 * @throws IOException
59 */
60 public void requestPTY(String term) throws IOException {
61 requestPTY(term, 0, 0, 0, 0, null);
62 }
63
64 /**
65 * Allocate a pseudo-terminal for this session.
66 * <p/>
67 * This method may only be called before a program or shell is started in
68 * this session.
69 * <p/>
70 * Different aspects can be specified:
71 * <p/>
72 * <ul>
73 * <li>The TERM environment variable value (e.g., vt100)</li>
74 * <li>The terminal's dimensions.</li>
75 * <li>The encoded terminal modes.</li>
76 * </ul>
77 * Zero dimension parameters are ignored. The character/row dimensions
78 * override the pixel dimensions (when nonzero). Pixel dimensions refer to
79 * the drawable area of the window. The dimension parameters are only
80 * informational. The encoding of terminal modes (parameter
81 * <code>terminal_modes</code>) is described in RFC4254.
82 *
83 * @param term The TERM environment variable value (e.g., vt100)
84 * @param term_width_characters terminal width, characters (e.g., 80)
85 * @param term_height_characters terminal height, rows (e.g., 24)
86 * @param term_width_pixels terminal width, pixels (e.g., 640)
87 * @param term_height_pixels terminal height, pixels (e.g., 480)
88 * @param terminal_modes encoded terminal modes (may be <code>null</code>)
89 * @throws IOException
90 */
91 public void requestPTY(String term, int term_width_characters, int term_height_characters, int term_width_pixels,
92 int term_height_pixels, byte[] terminal_modes) throws IOException {
93 if (term == null)
94 throw new IllegalArgumentException("TERM cannot be null.");
95
96 if ((terminal_modes != null) && (terminal_modes.length > 0)) {
97 if (terminal_modes[terminal_modes.length - 1] != 0)
98 throw new IOException("Illegal terminal modes description, does not end in zero byte");
99 }
100 else
101 terminal_modes = new byte[] {0};
102
103 synchronized (this) {
104 /* The following is just a nicer error, we would catch it anyway later in the channel code */
105 if (flag_closed)
106 throw new IOException("This session is closed.");
107
108 if (flag_pty_requested)
109 throw new IOException("A PTY was already requested.");
110
111 if (flag_execution_started)
112 throw new IOException(
113 "Cannot request PTY at this stage anymore, a remote execution has already started.");
114
115 flag_pty_requested = true;
116 }
117
118 cm.requestPTY(cn, term, term_width_characters, term_height_characters, term_width_pixels, term_height_pixels,
119 terminal_modes);
120 }
121
122 /**
123 * Tells the server that the size of the terminal has changed.
124 *
125 * See {@link #requestPTY(String, int, int, int, int, byte[])} for more details about how parameters are interpreted.
126 *
127 * @param term_width_characters
128 * terminal width, characters (e.g., 80)
129 * @param term_height_characters
130 * terminal height, rows (e.g., 24)
131 * @param term_width_pixels
132 * terminal width, pixels (e.g., 640)
133 * @param term_height_pixels
134 * terminal height, pixels (e.g., 480)
135 * @throws IOException
136 */
137 public void resizePTY(int term_width_characters, int term_height_characters, int term_width_pixels, int term_height_pixels) throws IOException {
138 requestWindowChange(term_width_characters, term_height_characters, term_width_pixels, term_height_pixels);
139 }
140
141 public void requestWindowChange(int term_width_characters, int term_height_characters, int term_width_pixels,
142 int term_height_pixels) throws IOException {
143 synchronized (this) {
144 /* The following is just a nicer error, we would catch it anyway later in the channel code */
145 if (flag_closed)
146 throw new IOException("This session is closed.");
147
148 if (!flag_pty_requested)
149 throw new IOException("A PTY was not requested.");
150 }
151
152 cm.requestWindowChange(cn, term_width_characters, term_height_characters, term_width_pixels, term_height_pixels);
153 }
154
155 /**
156 * Request X11 forwarding for the current session.
157 * <p/>
158 * You have to supply the name and port of your X-server.
159 * <p/>
160 * This method may only be called before a program or shell is started in
161 * this session.
162 *
163 * @param hostname the hostname of the real (target) X11 server (e.g., 127.0.0.1)
164 * @param port the port of the real (target) X11 server (e.g., 6010)
165 * @param cookie if non-null, then present this cookie to the real X11 server
166 * @param singleConnection if true, then the server is instructed to only forward one single
167 * connection, no more connections shall be forwarded after first, or after the session
168 * channel has been closed
169 * @throws IOException
170 */
171 public void requestX11Forwarding(String hostname, int port, byte[] cookie, boolean singleConnection)
172 throws IOException {
173 if (hostname == null)
174 throw new IllegalArgumentException("hostname argument may not be null");
175
176 synchronized (this) {
177 /* The following is just a nicer error, we would catch it anyway later in the channel code */
178 if (flag_closed)
179 throw new IOException("This session is closed.");
180
181 if (flag_x11_requested)
182 throw new IOException("X11 forwarding was already requested.");
183
184 if (flag_execution_started)
185 throw new IOException(
186 "Cannot request X11 forwarding at this stage anymore, a remote execution has already started.");
187
188 flag_x11_requested = true;
189 }
190
191 /* X11ServerData - used to store data about the target X11 server */
192 X11ServerData x11data = new X11ServerData();
193 x11data.hostname = hostname;
194 x11data.port = port;
195 x11data.x11_magic_cookie = cookie; /* if non-null, then present this cookie to the real X11 server */
196 /* Generate fake cookie - this one is used between remote clients and the ganymed proxy */
197 byte[] fakeCookie = new byte[16];
198 String hexEncodedFakeCookie;
199
200 /* Make sure that this fake cookie is unique for this connection */
201
202 while (true) {
203 rnd.nextBytes(fakeCookie);
204 /* Generate also hex representation of fake cookie */
205 StringBuilder tmp = new StringBuilder(32);
206
207 for (int i = 0; i < fakeCookie.length; i++) {
208 String digit2 = Integer.toHexString(fakeCookie[i] & 0xff);
209 tmp.append((digit2.length() == 2) ? digit2 : "0" + digit2);
210 }
211
212 hexEncodedFakeCookie = tmp.toString();
213
214 /* Well, yes, chances are low, but we want to be on the safe side */
215
216 if (cm.checkX11Cookie(hexEncodedFakeCookie) == null)
217 break;
218 }
219
220 /* Ask for X11 forwarding */
221 cm.requestX11(cn, singleConnection, "MIT-MAGIC-COOKIE-1", hexEncodedFakeCookie, 0);
222
223 /* OK, that went fine, get ready to accept X11 connections... */
224 /* ... but only if the user has not called close() in the meantime =) */
225
226 synchronized (this) {
227 if (flag_closed == false) {
228 this.x11FakeCookie = hexEncodedFakeCookie;
229 cm.registerX11Cookie(hexEncodedFakeCookie, x11data);
230 }
231 }
232
233 /* Now it is safe to start remote X11 programs */
234 }
235
236 /**
237 * Execute a command on the remote machine.
238 *
239 * @param cmd The command to execute on the remote host.
240 * @throws IOException
241 */
242 public void execCommand(String cmd) throws IOException {
243 this.execCommand(cmd, null);
244 }
245
246 /**
247 * Execute a command on the remote machine.
248 *
249 * @param cmd The command to execute on the remote host.
250 * @param charsetName The charset used to convert between Java Unicode Strings and byte encodings
251 * @throws IOException
252 */
253 public void execCommand(String cmd, String charsetName) throws IOException {
254 if (cmd == null)
255 throw new IllegalArgumentException("cmd argument may not be null");
256
257 synchronized (this) {
258 /* The following is just a nicer error, we would catch it anyway later in the channel code */
259 if (flag_closed)
260 throw new IOException("This session is closed.");
261
262 if (flag_execution_started)
263 throw new IOException("A remote execution has already started.");
264
265 flag_execution_started = true;
266 }
267
268 cm.requestExecCommand(cn, cmd, charsetName);
269 }
270
271 /**
272 * Start a shell on the remote machine.
273 *
274 * @throws IOException
275 */
276 public void startShell() throws IOException {
277 synchronized (this) {
278 /* The following is just a nicer error, we would catch it anyway later in the channel code */
279 if (flag_closed)
280 throw new IOException("This session is closed.");
281
282 if (flag_execution_started)
283 throw new IOException("A remote execution has already started.");
284
285 flag_execution_started = true;
286 }
287
288 cm.requestShell(cn);
289 }
290
291 /**
292 * Start a subsystem on the remote machine.
293 * Unless you know what you are doing, you will never need this.
294 *
295 * @param name the name of the subsystem.
296 * @throws IOException
297 */
298 public void startSubSystem(String name) throws IOException {
299 if (name == null)
300 throw new IllegalArgumentException("name argument may not be null");
301
302 synchronized (this) {
303 /* The following is just a nicer error, we would catch it anyway later in the channel code */
304 if (flag_closed)
305 throw new IOException("This session is closed.");
306
307 if (flag_execution_started)
308 throw new IOException("A remote execution has already started.");
309
310 flag_execution_started = true;
311 }
312
313 cm.requestSubSystem(cn, name);
314 }
315
316 /**
317 * Request authentication agent forwarding.
318 * @param agent object that implements the callbacks
319 *
320 * @throws IOException in case of any problem or when the session is closed
321 */
322
323 public synchronized void requestAuthAgentForwarding(AuthAgentCallback agent) throws IOException {
324 synchronized (this) {
325 /*
326 * The following is just a nicer error, we would catch it anyway
327 * later in the channel code
328 */
329 if (flag_closed)
330 throw new IOException("This session is closed.");
331 }
332
333 cm.requestChannelAgentForwarding(cn, agent);
334 }
335
336 public int getState() {
337 return cn.getState();
338 }
339
340 public InputStream getStdout() {
341 return cn.getStdoutStream();
342 }
343
344 public InputStream getStderr() {
345 return cn.getStderrStream();
346 }
347
348 public OutputStream getStdin() {
349 return cn.getStdinStream();
350 }
351
352 /**
353 * This method blocks until there is more data available on either the
354 * stdout or stderr InputStream of this <code>Session</code>. Very useful
355 * if you do not want to use two parallel threads for reading from the two
356 * InputStreams. One can also specify a timeout. NOTE: do NOT call this
357 * method if you use concurrent threads that operate on either of the two
358 * InputStreams of this <code>Session</code> (otherwise this method may
359 * block, even though more data is available).
360 *
361 * @param timeout The (non-negative) timeout in <code>ms</code>. <code>0</code> means no
362 * timeout, the call may block forever.
363 * @return <ul>
364 * <li><code>0</code> if no more data will arrive.</li>
365 * <li><code>1</code> if more data is available.</li>
366 * <li><code>-1</code> if a timeout occurred.</li>
367 * </ul>
368 * @throws IOException
369 * @deprecated This method has been replaced with a much more powerful wait-for-condition
370 * interface and therefore acts only as a wrapper.
371 */
372 public int waitUntilDataAvailable(long timeout) throws IOException {
373 if (timeout < 0)
374 throw new IllegalArgumentException("timeout must not be negative!");
375
376 int conditions = cm.waitForCondition(cn, timeout, ChannelCondition.STDOUT_DATA | ChannelCondition.STDERR_DATA
377 | ChannelCondition.EOF);
378
379 if ((conditions & ChannelCondition.TIMEOUT) != 0)
380 return -1;
381
382 if ((conditions & (ChannelCondition.STDOUT_DATA | ChannelCondition.STDERR_DATA)) != 0)
383 return 1;
384
385 /* Here we do not need to check separately for CLOSED, since CLOSED implies EOF */
386
387 if ((conditions & ChannelCondition.EOF) != 0)
388 return 0;
389
390 throw new IllegalStateException("Unexpected condition result (" + conditions + ")");
391 }
392
393 /**
394 * This method blocks until certain conditions hold true on the underlying SSH-2 channel.
395 * <p/>
396 * This method returns as soon as one of the following happens:
397 * <ul>
398 * <li>at least of the specified conditions (see {@link ChannelCondition}) holds true</li>
399 * <li>timeout > 0 and a timeout occured (TIMEOUT will be set in result conditions)</a>
400 * <li>the underlying channel was closed (CLOSED will be set in result conditions)</a>
401 * </ul>
402 * <p/>
403 * In any case, the result value contains ALL current conditions, which may be more
404 * than the specified condition set (i.e., never use the "==" operator to test for conditions
405 * in the bitmask, see also comments in {@link ChannelCondition}).
406 * <p/>
407 * Note: do NOT call this method if you want to wait for STDOUT_DATA or STDERR_DATA and
408 * there are concurrent threads (e.g., StreamGobblers) that operate on either of the two
409 * InputStreams of this <code>Session</code> (otherwise this method may
410 * block, even though more data is available in the StreamGobblers).
411 *
412 * @param condition_set a bitmask based on {@link ChannelCondition} values
413 * @param timeout non-negative timeout in ms, <code>0</code> means no timeout
414 * @return all bitmask specifying all current conditions that are true
415 */
416
417 public int waitForCondition(int condition_set, long timeout) throws IOException {
418 if (timeout < 0)
419 throw new IllegalArgumentException("timeout must be non-negative!");
420
421 return cm.waitForCondition(cn, timeout, condition_set);
422 }
423
424 /**
425 * Get the exit code/status from the remote command - if available. Be
426 * careful - not all server implementations return this value. It is
427 * generally a good idea to call this method only when all data from the
428 * remote side has been consumed (see also the <code<WaitForCondition</code> method).
429 *
430 * @return An <code>Integer</code> holding the exit code, or
431 * <code>null</code> if no exit code is (yet) available.
432 */
433 public Integer getExitStatus() {
434 return cn.getExitStatus();
435 }
436
437 /**
438 * Get the name of the signal by which the process on the remote side was
439 * stopped - if available and applicable. Be careful - not all server
440 * implementations return this value.
441 *
442 * @return An <code>String</code> holding the name of the signal, or
443 * <code>null</code> if the process exited normally or is still
444 * running (or if the server forgot to send this information).
445 */
446 public String getExitSignal() {
447 return cn.getExitSignal();
448 }
449
450 /**
451 * Close this session. NEVER forget to call this method to free up resources -
452 * even if you got an exception from one of the other methods (or when
453 * getting an Exception on the Input- or OutputStreams). Sometimes these other
454 * methods may throw an exception, saying that the underlying channel is
455 * closed (this can happen, e.g., if the other server sent a close message.)
456 * However, as long as you have not called the <code>close()</code>
457 * method, you may be wasting (local) resources.
458 */
459 public void close() {
460 synchronized (this) {
461 if (flag_closed)
462 return;
463
464 flag_closed = true;
465
466 if (x11FakeCookie != null)
467 cm.unRegisterX11Cookie(x11FakeCookie, true);
468
469 try {
470 cm.closeChannel(cn, "Closed due to user request", true);
471 }
472 catch (IOException ignored) {
473 }
474 }
475 }
476 }