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1 | /* | |
2 | * | |
3 | * clientloop.c | |
4 | * | |
5 | * Author: Tatu Ylonen <ylo@cs.hut.fi> | |
6 | * | |
7 | * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland | |
8 | * All rights reserved | |
9 | * | |
10 | * | |
11 | * Created: Sat Sep 23 12:23:57 1995 ylo | |
12 | * | |
13 | * The main loop for the interactive session (client side). | |
14 | * | |
15 | */ | |
16 | ||
17 | #include "includes.h" | |
18 | RCSID("$Id$"); | |
19 | ||
20 | #include "xmalloc.h" | |
21 | #include "ssh.h" | |
22 | #include "packet.h" | |
23 | #include "buffer.h" | |
24 | #include "authfd.h" | |
25 | #include "readconf.h" | |
26 | ||
27 | /* Flag indicating that stdin should be redirected from /dev/null. */ | |
28 | extern int stdin_null_flag; | |
29 | ||
30 | /* | |
31 | * Name of the host we are connecting to. This is the name given on the | |
32 | * command line, or the HostName specified for the user-supplied name in a | |
33 | * configuration file. | |
34 | */ | |
35 | extern char *host; | |
36 | ||
37 | /* | |
38 | * Flag to indicate that we have received a window change signal which has | |
39 | * not yet been processed. This will cause a message indicating the new | |
40 | * window size to be sent to the server a little later. This is volatile | |
41 | * because this is updated in a signal handler. | |
42 | */ | |
43 | static volatile int received_window_change_signal = 0; | |
44 | ||
45 | /* Terminal modes, as saved by enter_raw_mode. */ | |
46 | static struct termios saved_tio; | |
47 | ||
48 | /* | |
49 | * Flag indicating whether we are in raw mode. This is used by | |
50 | * enter_raw_mode and leave_raw_mode. | |
51 | */ | |
52 | static int in_raw_mode = 0; | |
53 | ||
54 | /* Flag indicating whether the user\'s terminal is in non-blocking mode. */ | |
55 | static int in_non_blocking_mode = 0; | |
56 | ||
57 | /* Common data for the client loop code. */ | |
58 | static int escape_pending; /* Last character was the escape character */ | |
59 | static int last_was_cr; /* Last character was a newline. */ | |
60 | static int exit_status; /* Used to store the exit status of the command. */ | |
61 | static int stdin_eof; /* EOF has been encountered on standard error. */ | |
62 | static Buffer stdin_buffer; /* Buffer for stdin data. */ | |
63 | static Buffer stdout_buffer; /* Buffer for stdout data. */ | |
64 | static Buffer stderr_buffer; /* Buffer for stderr data. */ | |
65 | static unsigned int buffer_high;/* Soft max buffer size. */ | |
66 | static int max_fd; /* Maximum file descriptor number in select(). */ | |
67 | static int connection_in; /* Connection to server (input). */ | |
68 | static int connection_out; /* Connection to server (output). */ | |
69 | static unsigned long stdin_bytes, stdout_bytes, stderr_bytes; | |
70 | static int quit_pending; /* Set to non-zero to quit the client loop. */ | |
71 | static int escape_char; /* Escape character. */ | |
72 | ||
73 | /* Returns the user\'s terminal to normal mode if it had been put in raw mode. */ | |
74 | ||
75 | void | |
76 | leave_raw_mode() | |
77 | { | |
78 | if (!in_raw_mode) | |
79 | return; | |
80 | in_raw_mode = 0; | |
81 | if (tcsetattr(fileno(stdin), TCSADRAIN, &saved_tio) < 0) | |
82 | perror("tcsetattr"); | |
83 | ||
84 | fatal_remove_cleanup((void (*) (void *)) leave_raw_mode, NULL); | |
85 | } | |
86 | ||
87 | /* Puts the user\'s terminal in raw mode. */ | |
88 | ||
89 | void | |
90 | enter_raw_mode() | |
91 | { | |
92 | struct termios tio; | |
93 | ||
94 | if (tcgetattr(fileno(stdin), &tio) < 0) | |
95 | perror("tcgetattr"); | |
96 | saved_tio = tio; | |
97 | tio.c_iflag |= IGNPAR; | |
98 | tio.c_iflag &= ~(ISTRIP | INLCR | IGNCR | ICRNL | IXON | IXANY | IXOFF); | |
99 | tio.c_lflag &= ~(ISIG | ICANON | ECHO | ECHOE | ECHOK | ECHONL); | |
100 | #ifdef IEXTEN | |
101 | tio.c_lflag &= ~IEXTEN; | |
102 | #endif /* IEXTEN */ | |
103 | tio.c_oflag &= ~OPOST; | |
104 | tio.c_cc[VMIN] = 1; | |
105 | tio.c_cc[VTIME] = 0; | |
106 | if (tcsetattr(fileno(stdin), TCSADRAIN, &tio) < 0) | |
107 | perror("tcsetattr"); | |
108 | in_raw_mode = 1; | |
109 | ||
110 | fatal_add_cleanup((void (*) (void *)) leave_raw_mode, NULL); | |
111 | } | |
112 | ||
113 | /* Restores stdin to blocking mode. */ | |
114 | ||
115 | void | |
116 | leave_non_blocking() | |
117 | { | |
118 | if (in_non_blocking_mode) { | |
119 | (void) fcntl(fileno(stdin), F_SETFL, 0); | |
120 | in_non_blocking_mode = 0; | |
121 | fatal_remove_cleanup((void (*) (void *)) leave_non_blocking, NULL); | |
122 | } | |
123 | } | |
124 | ||
125 | /* Puts stdin terminal in non-blocking mode. */ | |
126 | ||
127 | void | |
128 | enter_non_blocking() | |
129 | { | |
130 | in_non_blocking_mode = 1; | |
131 | (void) fcntl(fileno(stdin), F_SETFL, O_NONBLOCK); | |
132 | fatal_add_cleanup((void (*) (void *)) leave_non_blocking, NULL); | |
133 | } | |
134 | ||
135 | /* | |
136 | * Signal handler for the window change signal (SIGWINCH). This just sets a | |
137 | * flag indicating that the window has changed. | |
138 | */ | |
139 | ||
140 | void | |
141 | window_change_handler(int sig) | |
142 | { | |
143 | received_window_change_signal = 1; | |
144 | signal(SIGWINCH, window_change_handler); | |
145 | } | |
146 | ||
147 | /* | |
148 | * Signal handler for signals that cause the program to terminate. These | |
149 | * signals must be trapped to restore terminal modes. | |
150 | */ | |
151 | ||
152 | void | |
153 | signal_handler(int sig) | |
154 | { | |
155 | if (in_raw_mode) | |
156 | leave_raw_mode(); | |
157 | if (in_non_blocking_mode) | |
158 | leave_non_blocking(); | |
159 | channel_stop_listening(); | |
160 | packet_close(); | |
161 | fatal("Killed by signal %d.", sig); | |
162 | } | |
163 | ||
164 | /* | |
165 | * Returns current time in seconds from Jan 1, 1970 with the maximum | |
166 | * available resolution. | |
167 | */ | |
168 | ||
169 | double | |
170 | get_current_time() | |
171 | { | |
172 | struct timeval tv; | |
173 | gettimeofday(&tv, NULL); | |
174 | return (double) tv.tv_sec + (double) tv.tv_usec / 1000000.0; | |
175 | } | |
176 | ||
177 | /* | |
178 | * This is called when the interactive is entered. This checks if there is | |
179 | * an EOF coming on stdin. We must check this explicitly, as select() does | |
180 | * not appear to wake up when redirecting from /dev/null. | |
181 | */ | |
182 | ||
183 | void | |
184 | client_check_initial_eof_on_stdin() | |
185 | { | |
186 | int len; | |
187 | char buf[1]; | |
188 | ||
189 | /* | |
190 | * If standard input is to be "redirected from /dev/null", we simply | |
191 | * mark that we have seen an EOF and send an EOF message to the | |
192 | * server. Otherwise, we try to read a single character; it appears | |
193 | * that for some files, such /dev/null, select() never wakes up for | |
194 | * read for this descriptor, which means that we never get EOF. This | |
195 | * way we will get the EOF if stdin comes from /dev/null or similar. | |
196 | */ | |
197 | if (stdin_null_flag) { | |
198 | /* Fake EOF on stdin. */ | |
199 | debug("Sending eof."); | |
200 | stdin_eof = 1; | |
201 | packet_start(SSH_CMSG_EOF); | |
202 | packet_send(); | |
203 | } else { | |
204 | enter_non_blocking(); | |
205 | ||
206 | /* Check for immediate EOF on stdin. */ | |
207 | len = read(fileno(stdin), buf, 1); | |
208 | if (len == 0) { | |
209 | /* EOF. Record that we have seen it and send EOF to server. */ | |
210 | debug("Sending eof."); | |
211 | stdin_eof = 1; | |
212 | packet_start(SSH_CMSG_EOF); | |
213 | packet_send(); | |
214 | } else if (len > 0) { | |
215 | /* | |
216 | * Got data. We must store the data in the buffer, | |
217 | * and also process it as an escape character if | |
218 | * appropriate. | |
219 | */ | |
220 | if ((unsigned char) buf[0] == escape_char) | |
221 | escape_pending = 1; | |
222 | else { | |
223 | buffer_append(&stdin_buffer, buf, 1); | |
224 | stdin_bytes += 1; | |
225 | } | |
226 | } | |
227 | leave_non_blocking(); | |
228 | } | |
229 | } | |
230 | ||
231 | /* | |
232 | * Get packets from the connection input buffer, and process them as long as | |
233 | * there are packets available. | |
234 | */ | |
235 | ||
236 | void | |
237 | client_process_buffered_input_packets() | |
238 | { | |
239 | int type; | |
240 | char *data; | |
241 | unsigned int data_len; | |
242 | int payload_len; | |
243 | ||
244 | /* Process any buffered packets from the server. */ | |
245 | while (!quit_pending && | |
246 | (type = packet_read_poll(&payload_len)) != SSH_MSG_NONE) { | |
247 | switch (type) { | |
248 | ||
249 | case SSH_SMSG_STDOUT_DATA: | |
250 | data = packet_get_string(&data_len); | |
251 | packet_integrity_check(payload_len, 4 + data_len, type); | |
252 | buffer_append(&stdout_buffer, data, data_len); | |
253 | stdout_bytes += data_len; | |
254 | memset(data, 0, data_len); | |
255 | xfree(data); | |
256 | break; | |
257 | ||
258 | case SSH_SMSG_STDERR_DATA: | |
259 | data = packet_get_string(&data_len); | |
260 | packet_integrity_check(payload_len, 4 + data_len, type); | |
261 | buffer_append(&stderr_buffer, data, data_len); | |
262 | stdout_bytes += data_len; | |
263 | memset(data, 0, data_len); | |
264 | xfree(data); | |
265 | break; | |
266 | ||
267 | case SSH_SMSG_EXITSTATUS: | |
268 | packet_integrity_check(payload_len, 4, type); | |
269 | exit_status = packet_get_int(); | |
270 | /* Acknowledge the exit. */ | |
271 | packet_start(SSH_CMSG_EXIT_CONFIRMATION); | |
272 | packet_send(); | |
273 | /* | |
274 | * Must wait for packet to be sent since we are | |
275 | * exiting the loop. | |
276 | */ | |
277 | packet_write_wait(); | |
278 | /* Flag that we want to exit. */ | |
279 | quit_pending = 1; | |
280 | break; | |
281 | ||
282 | case SSH_SMSG_X11_OPEN: | |
283 | x11_input_open(payload_len); | |
284 | break; | |
285 | ||
286 | case SSH_MSG_PORT_OPEN: | |
287 | channel_input_port_open(payload_len); | |
288 | break; | |
289 | ||
290 | case SSH_SMSG_AGENT_OPEN: | |
291 | packet_integrity_check(payload_len, 4, type); | |
292 | auth_input_open_request(); | |
293 | break; | |
294 | ||
295 | case SSH_MSG_CHANNEL_OPEN_CONFIRMATION: | |
296 | packet_integrity_check(payload_len, 4 + 4, type); | |
297 | channel_input_open_confirmation(); | |
298 | break; | |
299 | ||
300 | case SSH_MSG_CHANNEL_OPEN_FAILURE: | |
301 | packet_integrity_check(payload_len, 4, type); | |
302 | channel_input_open_failure(); | |
303 | break; | |
304 | ||
305 | case SSH_MSG_CHANNEL_DATA: | |
306 | channel_input_data(payload_len); | |
307 | break; | |
308 | ||
309 | case SSH_MSG_CHANNEL_CLOSE: | |
310 | packet_integrity_check(payload_len, 4, type); | |
311 | channel_input_close(); | |
312 | break; | |
313 | ||
314 | case SSH_MSG_CHANNEL_CLOSE_CONFIRMATION: | |
315 | packet_integrity_check(payload_len, 4, type); | |
316 | channel_input_close_confirmation(); | |
317 | break; | |
318 | ||
319 | default: | |
320 | /* | |
321 | * Any unknown packets received during the actual | |
322 | * session cause the session to terminate. This is | |
323 | * intended to make debugging easier since no | |
324 | * confirmations are sent. Any compatible protocol | |
325 | * extensions must be negotiated during the | |
326 | * preparatory phase. | |
327 | */ | |
328 | packet_disconnect("Protocol error during session: type %d", | |
329 | type); | |
330 | } | |
331 | } | |
332 | } | |
333 | ||
334 | /* | |
335 | * Make packets from buffered stdin data, and buffer them for sending to the | |
336 | * connection. | |
337 | */ | |
338 | ||
339 | void | |
340 | client_make_packets_from_stdin_data() | |
341 | { | |
342 | unsigned int len; | |
343 | ||
344 | /* Send buffered stdin data to the server. */ | |
345 | while (buffer_len(&stdin_buffer) > 0 && | |
346 | packet_not_very_much_data_to_write()) { | |
347 | len = buffer_len(&stdin_buffer); | |
348 | /* Keep the packets at reasonable size. */ | |
349 | if (len > packet_get_maxsize()) | |
350 | len = packet_get_maxsize(); | |
351 | packet_start(SSH_CMSG_STDIN_DATA); | |
352 | packet_put_string(buffer_ptr(&stdin_buffer), len); | |
353 | packet_send(); | |
354 | buffer_consume(&stdin_buffer, len); | |
355 | /* If we have a pending EOF, send it now. */ | |
356 | if (stdin_eof && buffer_len(&stdin_buffer) == 0) { | |
357 | packet_start(SSH_CMSG_EOF); | |
358 | packet_send(); | |
359 | } | |
360 | } | |
361 | } | |
362 | ||
363 | /* | |
364 | * Checks if the client window has changed, and sends a packet about it to | |
365 | * the server if so. The actual change is detected elsewhere (by a software | |
366 | * interrupt on Unix); this just checks the flag and sends a message if | |
367 | * appropriate. | |
368 | */ | |
369 | ||
370 | void | |
371 | client_check_window_change() | |
372 | { | |
373 | /* Send possible window change message to the server. */ | |
374 | if (received_window_change_signal) { | |
375 | struct winsize ws; | |
376 | ||
377 | /* Clear the window change indicator. */ | |
378 | received_window_change_signal = 0; | |
379 | ||
380 | /* Read new window size. */ | |
381 | if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) >= 0) { | |
382 | /* Successful, send the packet now. */ | |
383 | packet_start(SSH_CMSG_WINDOW_SIZE); | |
384 | packet_put_int(ws.ws_row); | |
385 | packet_put_int(ws.ws_col); | |
386 | packet_put_int(ws.ws_xpixel); | |
387 | packet_put_int(ws.ws_ypixel); | |
388 | packet_send(); | |
389 | } | |
390 | } | |
391 | } | |
392 | ||
393 | /* | |
394 | * Waits until the client can do something (some data becomes available on | |
395 | * one of the file descriptors). | |
396 | */ | |
397 | ||
398 | void | |
399 | client_wait_until_can_do_something(fd_set * readset, fd_set * writeset) | |
400 | { | |
401 | /* Initialize select masks. */ | |
402 | FD_ZERO(readset); | |
403 | ||
404 | /* Read from the connection, unless our buffers are full. */ | |
405 | if (buffer_len(&stdout_buffer) < buffer_high && | |
406 | buffer_len(&stderr_buffer) < buffer_high && | |
407 | channel_not_very_much_buffered_data()) | |
408 | FD_SET(connection_in, readset); | |
409 | ||
410 | /* | |
411 | * Read from stdin, unless we have seen EOF or have very much | |
412 | * buffered data to send to the server. | |
413 | */ | |
414 | if (!stdin_eof && packet_not_very_much_data_to_write()) | |
415 | FD_SET(fileno(stdin), readset); | |
416 | ||
417 | FD_ZERO(writeset); | |
418 | ||
419 | /* Add any selections by the channel mechanism. */ | |
420 | channel_prepare_select(readset, writeset); | |
421 | ||
422 | /* Select server connection if have data to write to the server. */ | |
423 | if (packet_have_data_to_write()) | |
424 | FD_SET(connection_out, writeset); | |
425 | ||
426 | /* Select stdout if have data in buffer. */ | |
427 | if (buffer_len(&stdout_buffer) > 0) | |
428 | FD_SET(fileno(stdout), writeset); | |
429 | ||
430 | /* Select stderr if have data in buffer. */ | |
431 | if (buffer_len(&stderr_buffer) > 0) | |
432 | FD_SET(fileno(stderr), writeset); | |
433 | ||
434 | /* Update maximum file descriptor number, if appropriate. */ | |
435 | if (channel_max_fd() > max_fd) | |
436 | max_fd = channel_max_fd(); | |
437 | ||
438 | /* | |
439 | * Wait for something to happen. This will suspend the process until | |
440 | * some selected descriptor can be read, written, or has some other | |
441 | * event pending. Note: if you want to implement SSH_MSG_IGNORE | |
442 | * messages to fool traffic analysis, this might be the place to do | |
443 | * it: just have a random timeout for the select, and send a random | |
444 | * SSH_MSG_IGNORE packet when the timeout expires. | |
445 | */ | |
446 | ||
447 | if (select(max_fd + 1, readset, writeset, NULL, NULL) < 0) { | |
448 | char buf[100]; | |
449 | /* Some systems fail to clear these automatically. */ | |
450 | FD_ZERO(readset); | |
451 | FD_ZERO(writeset); | |
452 | if (errno == EINTR) | |
453 | return; | |
454 | /* Note: we might still have data in the buffers. */ | |
455 | snprintf(buf, sizeof buf, "select: %s\r\n", strerror(errno)); | |
456 | buffer_append(&stderr_buffer, buf, strlen(buf)); | |
457 | stderr_bytes += strlen(buf); | |
458 | quit_pending = 1; | |
459 | } | |
460 | } | |
461 | ||
462 | void | |
463 | client_suspend_self() | |
464 | { | |
465 | struct winsize oldws, newws; | |
466 | ||
467 | /* Flush stdout and stderr buffers. */ | |
468 | if (buffer_len(&stdout_buffer) > 0) | |
469 | atomicio(write, fileno(stdout), buffer_ptr(&stdout_buffer), | |
470 | buffer_len(&stdout_buffer)); | |
471 | if (buffer_len(&stderr_buffer) > 0) | |
472 | atomicio(write, fileno(stderr), buffer_ptr(&stderr_buffer), | |
473 | buffer_len(&stderr_buffer)); | |
474 | ||
475 | leave_raw_mode(); | |
476 | ||
477 | /* | |
478 | * Free (and clear) the buffer to reduce the amount of data that gets | |
479 | * written to swap. | |
480 | */ | |
481 | buffer_free(&stdin_buffer); | |
482 | buffer_free(&stdout_buffer); | |
483 | buffer_free(&stderr_buffer); | |
484 | ||
485 | /* Save old window size. */ | |
486 | ioctl(fileno(stdin), TIOCGWINSZ, &oldws); | |
487 | ||
488 | /* Send the suspend signal to the program itself. */ | |
489 | kill(getpid(), SIGTSTP); | |
490 | ||
491 | /* Check if the window size has changed. */ | |
492 | if (ioctl(fileno(stdin), TIOCGWINSZ, &newws) >= 0 && | |
493 | (oldws.ws_row != newws.ws_row || | |
494 | oldws.ws_col != newws.ws_col || | |
495 | oldws.ws_xpixel != newws.ws_xpixel || | |
496 | oldws.ws_ypixel != newws.ws_ypixel)) | |
497 | received_window_change_signal = 1; | |
498 | ||
499 | /* OK, we have been continued by the user. Reinitialize buffers. */ | |
500 | buffer_init(&stdin_buffer); | |
501 | buffer_init(&stdout_buffer); | |
502 | buffer_init(&stderr_buffer); | |
503 | ||
504 | enter_raw_mode(); | |
505 | } | |
506 | ||
507 | void | |
508 | client_process_input(fd_set * readset) | |
509 | { | |
510 | int len, pid; | |
511 | char buf[8192], *s; | |
512 | ||
513 | /* | |
514 | * Read input from the server, and add any such data to the buffer of | |
515 | * the packet subsystem. | |
516 | */ | |
517 | if (FD_ISSET(connection_in, readset)) { | |
518 | /* Read as much as possible. */ | |
519 | len = read(connection_in, buf, sizeof(buf)); | |
520 | if (len == 0) { | |
521 | /* Received EOF. The remote host has closed the connection. */ | |
522 | snprintf(buf, sizeof buf, "Connection to %.300s closed by remote host.\r\n", | |
523 | host); | |
524 | buffer_append(&stderr_buffer, buf, strlen(buf)); | |
525 | stderr_bytes += strlen(buf); | |
526 | quit_pending = 1; | |
527 | return; | |
528 | } | |
529 | /* | |
530 | * There is a kernel bug on Solaris that causes select to | |
531 | * sometimes wake up even though there is no data available. | |
532 | */ | |
533 | if (len < 0 && errno == EAGAIN) | |
534 | len = 0; | |
535 | ||
536 | if (len < 0) { | |
537 | /* An error has encountered. Perhaps there is a network problem. */ | |
538 | snprintf(buf, sizeof buf, "Read from remote host %.300s: %.100s\r\n", | |
539 | host, strerror(errno)); | |
540 | buffer_append(&stderr_buffer, buf, strlen(buf)); | |
541 | stderr_bytes += strlen(buf); | |
542 | quit_pending = 1; | |
543 | return; | |
544 | } | |
545 | packet_process_incoming(buf, len); | |
546 | } | |
547 | /* Read input from stdin. */ | |
548 | if (FD_ISSET(fileno(stdin), readset)) { | |
549 | /* Read as much as possible. */ | |
550 | len = read(fileno(stdin), buf, sizeof(buf)); | |
551 | if (len <= 0) { | |
552 | /* | |
553 | * Received EOF or error. They are treated | |
554 | * similarly, except that an error message is printed | |
555 | * if it was an error condition. | |
556 | */ | |
557 | if (len < 0) { | |
558 | snprintf(buf, sizeof buf, "read: %.100s\r\n", strerror(errno)); | |
559 | buffer_append(&stderr_buffer, buf, strlen(buf)); | |
560 | stderr_bytes += strlen(buf); | |
561 | } | |
562 | /* Mark that we have seen EOF. */ | |
563 | stdin_eof = 1; | |
564 | /* | |
565 | * Send an EOF message to the server unless there is | |
566 | * data in the buffer. If there is data in the | |
567 | * buffer, no message will be sent now. Code | |
568 | * elsewhere will send the EOF when the buffer | |
569 | * becomes empty if stdin_eof is set. | |
570 | */ | |
571 | if (buffer_len(&stdin_buffer) == 0) { | |
572 | packet_start(SSH_CMSG_EOF); | |
573 | packet_send(); | |
574 | } | |
575 | } else if (escape_char == -1) { | |
576 | /* | |
577 | * Normal successful read, and no escape character. | |
578 | * Just append the data to buffer. | |
579 | */ | |
580 | buffer_append(&stdin_buffer, buf, len); | |
581 | stdin_bytes += len; | |
582 | } else { | |
583 | /* | |
584 | * Normal, successful read. But we have an escape character | |
585 | * and have to process the characters one by one. | |
586 | */ | |
587 | unsigned int i; | |
588 | for (i = 0; i < len; i++) { | |
589 | unsigned char ch; | |
590 | /* Get one character at a time. */ | |
591 | ch = buf[i]; | |
592 | ||
593 | if (escape_pending) { | |
594 | /* We have previously seen an escape character. */ | |
595 | /* Clear the flag now. */ | |
596 | escape_pending = 0; | |
597 | /* Process the escaped character. */ | |
598 | switch (ch) { | |
599 | case '.': | |
600 | /* Terminate the connection. */ | |
601 | snprintf(buf, sizeof buf, "%c.\r\n", escape_char); | |
602 | buffer_append(&stderr_buffer, buf, strlen(buf)); | |
603 | stderr_bytes += strlen(buf); | |
604 | quit_pending = 1; | |
605 | return; | |
606 | ||
607 | case 'Z' - 64: | |
608 | /* Suspend the program. */ | |
609 | /* Print a message to that effect to the user. */ | |
610 | snprintf(buf, sizeof buf, "%c^Z\r\n", escape_char); | |
611 | buffer_append(&stderr_buffer, buf, strlen(buf)); | |
612 | stderr_bytes += strlen(buf); | |
613 | ||
614 | /* Restore terminal modes and suspend. */ | |
615 | client_suspend_self(); | |
616 | ||
617 | /* We have been continued. */ | |
618 | continue; | |
619 | ||
620 | case '&': | |
621 | /* | |
622 | * Detach the program (continue to serve connections, | |
623 | * but put in background and no more new connections). | |
624 | */ | |
625 | if (!stdin_eof) { | |
626 | /* | |
627 | * Sending SSH_CMSG_EOF alone does not always appear | |
628 | * to be enough. So we try to send an EOF character | |
629 | * first. | |
630 | */ | |
631 | packet_start(SSH_CMSG_STDIN_DATA); | |
632 | packet_put_string("\004", 1); | |
633 | packet_send(); | |
634 | /* Close stdin. */ | |
635 | stdin_eof = 1; | |
636 | if (buffer_len(&stdin_buffer) == 0) { | |
637 | packet_start(SSH_CMSG_EOF); | |
638 | packet_send(); | |
639 | } | |
640 | } | |
641 | /* Restore tty modes. */ | |
642 | leave_raw_mode(); | |
643 | ||
644 | /* Stop listening for new connections. */ | |
645 | channel_stop_listening(); | |
646 | ||
647 | printf("%c& [backgrounded]\n", escape_char); | |
648 | ||
649 | /* Fork into background. */ | |
650 | pid = fork(); | |
651 | if (pid < 0) { | |
652 | error("fork: %.100s", strerror(errno)); | |
653 | continue; | |
654 | } | |
655 | if (pid != 0) { /* This is the parent. */ | |
656 | /* The parent just exits. */ | |
657 | exit(0); | |
658 | } | |
659 | /* The child continues serving connections. */ | |
660 | continue; | |
661 | ||
662 | case '?': | |
663 | snprintf(buf, sizeof buf, | |
664 | "%c?\r\n\ | |
665 | Supported escape sequences:\r\n\ | |
666 | ~. - terminate connection\r\n\ | |
667 | ~^Z - suspend ssh\r\n\ | |
668 | ~# - list forwarded connections\r\n\ | |
669 | ~& - background ssh (when waiting for connections to terminate)\r\n\ | |
670 | ~? - this message\r\n\ | |
671 | ~~ - send the escape character by typing it twice\r\n\ | |
672 | (Note that escapes are only recognized immediately after newline.)\r\n", | |
673 | escape_char); | |
674 | buffer_append(&stderr_buffer, buf, strlen(buf)); | |
675 | continue; | |
676 | ||
677 | case '#': | |
678 | snprintf(buf, sizeof buf, "%c#\r\n", escape_char); | |
679 | buffer_append(&stderr_buffer, buf, strlen(buf)); | |
680 | s = channel_open_message(); | |
681 | buffer_append(&stderr_buffer, s, strlen(s)); | |
682 | xfree(s); | |
683 | continue; | |
684 | ||
685 | default: | |
686 | if (ch != escape_char) { | |
687 | /* | |
688 | * Escape character followed by non-special character. | |
689 | * Append both to the input buffer. | |
690 | */ | |
691 | buf[0] = escape_char; | |
692 | buf[1] = ch; | |
693 | buffer_append(&stdin_buffer, buf, 2); | |
694 | stdin_bytes += 2; | |
695 | continue; | |
696 | } | |
697 | /* | |
698 | * Note that escape character typed twice | |
699 | * falls through here; the latter gets processed | |
700 | * as a normal character below. | |
701 | */ | |
702 | break; | |
703 | } | |
704 | } else { | |
705 | /* | |
706 | * The previous character was not an escape char. Check if this | |
707 | * is an escape. | |
708 | */ | |
709 | if (last_was_cr && ch == escape_char) { | |
710 | /* It is. Set the flag and continue to next character. */ | |
711 | escape_pending = 1; | |
712 | continue; | |
713 | } | |
714 | } | |
715 | ||
716 | /* | |
717 | * Normal character. Record whether it was a newline, | |
718 | * and append it to the buffer. | |
719 | */ | |
720 | last_was_cr = (ch == '\r' || ch == '\n'); | |
721 | buf[0] = ch; | |
722 | buffer_append(&stdin_buffer, buf, 1); | |
723 | stdin_bytes += 1; | |
724 | continue; | |
725 | } | |
726 | } | |
727 | } | |
728 | } | |
729 | ||
730 | void | |
731 | client_process_output(fd_set * writeset) | |
732 | { | |
733 | int len; | |
734 | char buf[100]; | |
735 | ||
736 | /* Write buffered output to stdout. */ | |
737 | if (FD_ISSET(fileno(stdout), writeset)) { | |
738 | /* Write as much data as possible. */ | |
739 | len = write(fileno(stdout), buffer_ptr(&stdout_buffer), | |
740 | buffer_len(&stdout_buffer)); | |
741 | if (len <= 0) { | |
742 | if (errno == EAGAIN) | |
743 | len = 0; | |
744 | else { | |
745 | /* | |
746 | * An error or EOF was encountered. Put an | |
747 | * error message to stderr buffer. | |
748 | */ | |
749 | snprintf(buf, sizeof buf, "write stdout: %.50s\r\n", strerror(errno)); | |
750 | buffer_append(&stderr_buffer, buf, strlen(buf)); | |
751 | stderr_bytes += strlen(buf); | |
752 | quit_pending = 1; | |
753 | return; | |
754 | } | |
755 | } | |
756 | /* Consume printed data from the buffer. */ | |
757 | buffer_consume(&stdout_buffer, len); | |
758 | } | |
759 | /* Write buffered output to stderr. */ | |
760 | if (FD_ISSET(fileno(stderr), writeset)) { | |
761 | /* Write as much data as possible. */ | |
762 | len = write(fileno(stderr), buffer_ptr(&stderr_buffer), | |
763 | buffer_len(&stderr_buffer)); | |
764 | if (len <= 0) { | |
765 | if (errno == EAGAIN) | |
766 | len = 0; | |
767 | else { | |
768 | /* EOF or error, but can't even print error message. */ | |
769 | quit_pending = 1; | |
770 | return; | |
771 | } | |
772 | } | |
773 | /* Consume printed characters from the buffer. */ | |
774 | buffer_consume(&stderr_buffer, len); | |
775 | } | |
776 | } | |
777 | ||
778 | /* | |
779 | * Implements the interactive session with the server. This is called after | |
780 | * the user has been authenticated, and a command has been started on the | |
781 | * remote host. If escape_char != -1, it is the character used as an escape | |
782 | * character for terminating or suspending the session. | |
783 | */ | |
784 | ||
785 | int | |
786 | client_loop(int have_pty, int escape_char_arg) | |
787 | { | |
788 | extern Options options; | |
789 | double start_time, total_time; | |
790 | int len; | |
791 | char buf[100]; | |
792 | ||
793 | debug("Entering interactive session."); | |
794 | ||
795 | start_time = get_current_time(); | |
796 | ||
797 | /* Initialize variables. */ | |
798 | escape_pending = 0; | |
799 | last_was_cr = 1; | |
800 | exit_status = -1; | |
801 | stdin_eof = 0; | |
802 | buffer_high = 64 * 1024; | |
803 | connection_in = packet_get_connection_in(); | |
804 | connection_out = packet_get_connection_out(); | |
805 | max_fd = connection_in; | |
806 | if (connection_out > max_fd) | |
807 | max_fd = connection_out; | |
808 | stdin_bytes = 0; | |
809 | stdout_bytes = 0; | |
810 | stderr_bytes = 0; | |
811 | quit_pending = 0; | |
812 | escape_char = escape_char_arg; | |
813 | ||
814 | /* Initialize buffers. */ | |
815 | buffer_init(&stdin_buffer); | |
816 | buffer_init(&stdout_buffer); | |
817 | buffer_init(&stderr_buffer); | |
818 | ||
819 | /* Set signal handlers to restore non-blocking mode. */ | |
820 | signal(SIGINT, signal_handler); | |
821 | signal(SIGQUIT, signal_handler); | |
822 | signal(SIGTERM, signal_handler); | |
823 | signal(SIGPIPE, SIG_IGN); | |
824 | if (have_pty) | |
825 | signal(SIGWINCH, window_change_handler); | |
826 | ||
827 | if (have_pty) | |
828 | enter_raw_mode(); | |
829 | ||
830 | /* Check if we should immediately send of on stdin. */ | |
831 | client_check_initial_eof_on_stdin(); | |
832 | ||
833 | /* Main loop of the client for the interactive session mode. */ | |
834 | while (!quit_pending) { | |
835 | fd_set readset, writeset; | |
836 | ||
837 | /* Process buffered packets sent by the server. */ | |
838 | client_process_buffered_input_packets(); | |
839 | ||
840 | /* | |
841 | * Make packets of buffered stdin data, and buffer them for | |
842 | * sending to the server. | |
843 | */ | |
844 | client_make_packets_from_stdin_data(); | |
845 | ||
846 | /* | |
847 | * Make packets from buffered channel data, and buffer them | |
848 | * for sending to the server. | |
849 | */ | |
850 | if (packet_not_very_much_data_to_write()) | |
851 | channel_output_poll(); | |
852 | ||
853 | /* | |
854 | * Check if the window size has changed, and buffer a message | |
855 | * about it to the server if so. | |
856 | */ | |
857 | client_check_window_change(); | |
858 | ||
859 | if (quit_pending) | |
860 | break; | |
861 | ||
862 | /* | |
863 | * Wait until we have something to do (something becomes | |
864 | * available on one of the descriptors). | |
865 | */ | |
866 | client_wait_until_can_do_something(&readset, &writeset); | |
867 | ||
868 | if (quit_pending) | |
869 | break; | |
870 | ||
871 | /* Do channel operations. */ | |
872 | channel_after_select(&readset, &writeset); | |
873 | ||
874 | /* | |
875 | * Process input from the connection and from stdin. Buffer | |
876 | * any data that is available. | |
877 | */ | |
878 | client_process_input(&readset); | |
879 | ||
880 | /* | |
881 | * Process output to stdout and stderr. Output to the | |
882 | * connection is processed elsewhere (above). | |
883 | */ | |
884 | client_process_output(&writeset); | |
885 | ||
886 | /* Send as much buffered packet data as possible to the sender. */ | |
887 | if (FD_ISSET(connection_out, &writeset)) | |
888 | packet_write_poll(); | |
889 | } | |
890 | ||
891 | /* Terminate the session. */ | |
892 | ||
893 | /* Stop watching for window change. */ | |
894 | if (have_pty) | |
895 | signal(SIGWINCH, SIG_DFL); | |
896 | ||
897 | /* Stop listening for connections. */ | |
898 | channel_stop_listening(); | |
899 | ||
900 | /* | |
901 | * In interactive mode (with pseudo tty) display a message indicating | |
902 | * that the connection has been closed. | |
903 | */ | |
904 | if (have_pty && options.log_level != SYSLOG_LEVEL_QUIET) { | |
905 | snprintf(buf, sizeof buf, "Connection to %.64s closed.\r\n", host); | |
906 | buffer_append(&stderr_buffer, buf, strlen(buf)); | |
907 | stderr_bytes += strlen(buf); | |
908 | } | |
909 | /* Output any buffered data for stdout. */ | |
910 | while (buffer_len(&stdout_buffer) > 0) { | |
911 | len = write(fileno(stdout), buffer_ptr(&stdout_buffer), | |
912 | buffer_len(&stdout_buffer)); | |
913 | if (len <= 0) { | |
914 | error("Write failed flushing stdout buffer."); | |
915 | break; | |
916 | } | |
917 | buffer_consume(&stdout_buffer, len); | |
918 | } | |
919 | ||
920 | /* Output any buffered data for stderr. */ | |
921 | while (buffer_len(&stderr_buffer) > 0) { | |
922 | len = write(fileno(stderr), buffer_ptr(&stderr_buffer), | |
923 | buffer_len(&stderr_buffer)); | |
924 | if (len <= 0) { | |
925 | error("Write failed flushing stderr buffer."); | |
926 | break; | |
927 | } | |
928 | buffer_consume(&stderr_buffer, len); | |
929 | } | |
930 | ||
931 | if (have_pty) | |
932 | leave_raw_mode(); | |
933 | ||
934 | /* Clear and free any buffers. */ | |
935 | memset(buf, 0, sizeof(buf)); | |
936 | buffer_free(&stdin_buffer); | |
937 | buffer_free(&stdout_buffer); | |
938 | buffer_free(&stderr_buffer); | |
939 | ||
940 | /* Report bytes transferred, and transfer rates. */ | |
941 | total_time = get_current_time() - start_time; | |
942 | debug("Transferred: stdin %lu, stdout %lu, stderr %lu bytes in %.1f seconds", | |
943 | stdin_bytes, stdout_bytes, stderr_bytes, total_time); | |
944 | if (total_time > 0) | |
945 | debug("Bytes per second: stdin %.1f, stdout %.1f, stderr %.1f", | |
946 | stdin_bytes / total_time, stdout_bytes / total_time, | |
947 | stderr_bytes / total_time); | |
948 | ||
949 | /* Return the exit status of the program. */ | |
950 | debug("Exit status %d", exit_status); | |
951 | return exit_status; | |
952 | } |