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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 | * SSH2 support added by Markus Friedl. | |
16 | */ | |
17 | ||
18 | #include "includes.h" | |
19 | RCSID("$Id$"); | |
20 | ||
21 | #include "xmalloc.h" | |
22 | #include "ssh.h" | |
23 | #include "packet.h" | |
24 | #include "buffer.h" | |
25 | #include "authfd.h" | |
26 | #include "readconf.h" | |
27 | ||
28 | #include "ssh2.h" | |
29 | #include "compat.h" | |
30 | #include "channels.h" | |
31 | #include "dispatch.h" | |
32 | ||
33 | ||
34 | /* Flag indicating that stdin should be redirected from /dev/null. */ | |
35 | extern int stdin_null_flag; | |
36 | ||
37 | /* | |
38 | * Name of the host we are connecting to. This is the name given on the | |
39 | * command line, or the HostName specified for the user-supplied name in a | |
40 | * configuration file. | |
41 | */ | |
42 | extern char *host; | |
43 | ||
44 | /* | |
45 | * Flag to indicate that we have received a window change signal which has | |
46 | * not yet been processed. This will cause a message indicating the new | |
47 | * window size to be sent to the server a little later. This is volatile | |
48 | * because this is updated in a signal handler. | |
49 | */ | |
50 | static volatile int received_window_change_signal = 0; | |
51 | ||
52 | /* Terminal modes, as saved by enter_raw_mode. */ | |
53 | static struct termios saved_tio; | |
54 | ||
55 | /* | |
56 | * Flag indicating whether we are in raw mode. This is used by | |
57 | * enter_raw_mode and leave_raw_mode. | |
58 | */ | |
59 | static int in_raw_mode = 0; | |
60 | ||
61 | /* Flag indicating whether the user\'s terminal is in non-blocking mode. */ | |
62 | static int in_non_blocking_mode = 0; | |
63 | ||
64 | /* Common data for the client loop code. */ | |
65 | static int escape_pending; /* Last character was the escape character */ | |
66 | static int last_was_cr; /* Last character was a newline. */ | |
67 | static int exit_status; /* Used to store the exit status of the command. */ | |
68 | static int stdin_eof; /* EOF has been encountered on standard error. */ | |
69 | static Buffer stdin_buffer; /* Buffer for stdin data. */ | |
70 | static Buffer stdout_buffer; /* Buffer for stdout data. */ | |
71 | static Buffer stderr_buffer; /* Buffer for stderr data. */ | |
72 | static unsigned int buffer_high;/* Soft max buffer size. */ | |
73 | static int max_fd; /* Maximum file descriptor number in select(). */ | |
74 | static int connection_in; /* Connection to server (input). */ | |
75 | static int connection_out; /* Connection to server (output). */ | |
76 | static unsigned long stdin_bytes, stdout_bytes, stderr_bytes; | |
77 | static int quit_pending; /* Set to non-zero to quit the client loop. */ | |
78 | static int escape_char; /* Escape character. */ | |
79 | ||
80 | ||
81 | void client_init_dispatch(void); | |
82 | int session_ident = -1; | |
83 | ||
84 | /* Returns the user\'s terminal to normal mode if it had been put in raw mode. */ | |
85 | ||
86 | void | |
87 | leave_raw_mode() | |
88 | { | |
89 | if (!in_raw_mode) | |
90 | return; | |
91 | in_raw_mode = 0; | |
92 | if (tcsetattr(fileno(stdin), TCSADRAIN, &saved_tio) < 0) | |
93 | perror("tcsetattr"); | |
94 | ||
95 | fatal_remove_cleanup((void (*) (void *)) leave_raw_mode, NULL); | |
96 | } | |
97 | ||
98 | /* Puts the user\'s terminal in raw mode. */ | |
99 | ||
100 | void | |
101 | enter_raw_mode() | |
102 | { | |
103 | struct termios tio; | |
104 | ||
105 | if (tcgetattr(fileno(stdin), &tio) < 0) | |
106 | perror("tcgetattr"); | |
107 | saved_tio = tio; | |
108 | tio.c_iflag |= IGNPAR; | |
109 | tio.c_iflag &= ~(ISTRIP | INLCR | IGNCR | ICRNL | IXON | IXANY | IXOFF); | |
110 | tio.c_lflag &= ~(ISIG | ICANON | ECHO | ECHOE | ECHOK | ECHONL); | |
111 | #ifdef IEXTEN | |
112 | tio.c_lflag &= ~IEXTEN; | |
113 | #endif /* IEXTEN */ | |
114 | tio.c_oflag &= ~OPOST; | |
115 | tio.c_cc[VMIN] = 1; | |
116 | tio.c_cc[VTIME] = 0; | |
117 | if (tcsetattr(fileno(stdin), TCSADRAIN, &tio) < 0) | |
118 | perror("tcsetattr"); | |
119 | in_raw_mode = 1; | |
120 | ||
121 | fatal_add_cleanup((void (*) (void *)) leave_raw_mode, NULL); | |
122 | } | |
123 | ||
124 | /* Restores stdin to blocking mode. */ | |
125 | ||
126 | void | |
127 | leave_non_blocking() | |
128 | { | |
129 | if (in_non_blocking_mode) { | |
130 | (void) fcntl(fileno(stdin), F_SETFL, 0); | |
131 | in_non_blocking_mode = 0; | |
132 | fatal_remove_cleanup((void (*) (void *)) leave_non_blocking, NULL); | |
133 | } | |
134 | } | |
135 | ||
136 | /* Puts stdin terminal in non-blocking mode. */ | |
137 | ||
138 | void | |
139 | enter_non_blocking() | |
140 | { | |
141 | in_non_blocking_mode = 1; | |
142 | (void) fcntl(fileno(stdin), F_SETFL, O_NONBLOCK); | |
143 | fatal_add_cleanup((void (*) (void *)) leave_non_blocking, NULL); | |
144 | } | |
145 | ||
146 | /* | |
147 | * Signal handler for the window change signal (SIGWINCH). This just sets a | |
148 | * flag indicating that the window has changed. | |
149 | */ | |
150 | ||
151 | void | |
152 | window_change_handler(int sig) | |
153 | { | |
154 | received_window_change_signal = 1; | |
155 | signal(SIGWINCH, window_change_handler); | |
156 | } | |
157 | ||
158 | /* | |
159 | * Signal handler for signals that cause the program to terminate. These | |
160 | * signals must be trapped to restore terminal modes. | |
161 | */ | |
162 | ||
163 | void | |
164 | signal_handler(int sig) | |
165 | { | |
166 | if (in_raw_mode) | |
167 | leave_raw_mode(); | |
168 | if (in_non_blocking_mode) | |
169 | leave_non_blocking(); | |
170 | channel_stop_listening(); | |
171 | packet_close(); | |
172 | fatal("Killed by signal %d.", sig); | |
173 | } | |
174 | ||
175 | /* | |
176 | * Returns current time in seconds from Jan 1, 1970 with the maximum | |
177 | * available resolution. | |
178 | */ | |
179 | ||
180 | double | |
181 | get_current_time() | |
182 | { | |
183 | struct timeval tv; | |
184 | gettimeofday(&tv, NULL); | |
185 | return (double) tv.tv_sec + (double) tv.tv_usec / 1000000.0; | |
186 | } | |
187 | ||
188 | /* | |
189 | * This is called when the interactive is entered. This checks if there is | |
190 | * an EOF coming on stdin. We must check this explicitly, as select() does | |
191 | * not appear to wake up when redirecting from /dev/null. | |
192 | */ | |
193 | ||
194 | void | |
195 | client_check_initial_eof_on_stdin() | |
196 | { | |
197 | int len; | |
198 | char buf[1]; | |
199 | ||
200 | /* | |
201 | * If standard input is to be "redirected from /dev/null", we simply | |
202 | * mark that we have seen an EOF and send an EOF message to the | |
203 | * server. Otherwise, we try to read a single character; it appears | |
204 | * that for some files, such /dev/null, select() never wakes up for | |
205 | * read for this descriptor, which means that we never get EOF. This | |
206 | * way we will get the EOF if stdin comes from /dev/null or similar. | |
207 | */ | |
208 | if (stdin_null_flag) { | |
209 | /* Fake EOF on stdin. */ | |
210 | debug("Sending eof."); | |
211 | stdin_eof = 1; | |
212 | packet_start(SSH_CMSG_EOF); | |
213 | packet_send(); | |
214 | } else { | |
215 | enter_non_blocking(); | |
216 | ||
217 | /* Check for immediate EOF on stdin. */ | |
218 | len = read(fileno(stdin), buf, 1); | |
219 | if (len == 0) { | |
220 | /* EOF. Record that we have seen it and send EOF to server. */ | |
221 | debug("Sending eof."); | |
222 | stdin_eof = 1; | |
223 | packet_start(SSH_CMSG_EOF); | |
224 | packet_send(); | |
225 | } else if (len > 0) { | |
226 | /* | |
227 | * Got data. We must store the data in the buffer, | |
228 | * and also process it as an escape character if | |
229 | * appropriate. | |
230 | */ | |
231 | if ((unsigned char) buf[0] == escape_char) | |
232 | escape_pending = 1; | |
233 | else { | |
234 | buffer_append(&stdin_buffer, buf, 1); | |
235 | stdin_bytes += 1; | |
236 | } | |
237 | } | |
238 | leave_non_blocking(); | |
239 | } | |
240 | } | |
241 | ||
242 | ||
243 | /* | |
244 | * Make packets from buffered stdin data, and buffer them for sending to the | |
245 | * connection. | |
246 | */ | |
247 | ||
248 | void | |
249 | client_make_packets_from_stdin_data() | |
250 | { | |
251 | unsigned int len; | |
252 | ||
253 | /* Send buffered stdin data to the server. */ | |
254 | while (buffer_len(&stdin_buffer) > 0 && | |
255 | packet_not_very_much_data_to_write()) { | |
256 | len = buffer_len(&stdin_buffer); | |
257 | /* Keep the packets at reasonable size. */ | |
258 | if (len > packet_get_maxsize()) | |
259 | len = packet_get_maxsize(); | |
260 | packet_start(SSH_CMSG_STDIN_DATA); | |
261 | packet_put_string(buffer_ptr(&stdin_buffer), len); | |
262 | packet_send(); | |
263 | buffer_consume(&stdin_buffer, len); | |
264 | /* If we have a pending EOF, send it now. */ | |
265 | if (stdin_eof && buffer_len(&stdin_buffer) == 0) { | |
266 | packet_start(SSH_CMSG_EOF); | |
267 | packet_send(); | |
268 | } | |
269 | } | |
270 | } | |
271 | ||
272 | /* | |
273 | * Checks if the client window has changed, and sends a packet about it to | |
274 | * the server if so. The actual change is detected elsewhere (by a software | |
275 | * interrupt on Unix); this just checks the flag and sends a message if | |
276 | * appropriate. | |
277 | */ | |
278 | ||
279 | void | |
280 | client_check_window_change() | |
281 | { | |
282 | struct winsize ws; | |
283 | ||
284 | if (! received_window_change_signal) | |
285 | return; | |
286 | /** XXX race */ | |
287 | received_window_change_signal = 0; | |
288 | ||
289 | if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0) | |
290 | return; | |
291 | ||
292 | debug("client_check_window_change: changed"); | |
293 | ||
294 | if (compat20) { | |
295 | channel_request_start(session_ident, "window-change", 0); | |
296 | packet_put_int(ws.ws_col); | |
297 | packet_put_int(ws.ws_row); | |
298 | packet_put_int(ws.ws_xpixel); | |
299 | packet_put_int(ws.ws_ypixel); | |
300 | packet_send(); | |
301 | } else { | |
302 | packet_start(SSH_CMSG_WINDOW_SIZE); | |
303 | packet_put_int(ws.ws_row); | |
304 | packet_put_int(ws.ws_col); | |
305 | packet_put_int(ws.ws_xpixel); | |
306 | packet_put_int(ws.ws_ypixel); | |
307 | packet_send(); | |
308 | } | |
309 | } | |
310 | ||
311 | /* | |
312 | * Waits until the client can do something (some data becomes available on | |
313 | * one of the file descriptors). | |
314 | */ | |
315 | ||
316 | void | |
317 | client_wait_until_can_do_something(fd_set * readset, fd_set * writeset) | |
318 | { | |
319 | /*debug("client_wait_until_can_do_something"); */ | |
320 | ||
321 | /* Initialize select masks. */ | |
322 | FD_ZERO(readset); | |
323 | FD_ZERO(writeset); | |
324 | ||
325 | if (!compat20) { | |
326 | /* Read from the connection, unless our buffers are full. */ | |
327 | if (buffer_len(&stdout_buffer) < buffer_high && | |
328 | buffer_len(&stderr_buffer) < buffer_high && | |
329 | channel_not_very_much_buffered_data()) | |
330 | FD_SET(connection_in, readset); | |
331 | /* | |
332 | * Read from stdin, unless we have seen EOF or have very much | |
333 | * buffered data to send to the server. | |
334 | */ | |
335 | if (!stdin_eof && packet_not_very_much_data_to_write()) | |
336 | FD_SET(fileno(stdin), readset); | |
337 | ||
338 | /* Select stdout/stderr if have data in buffer. */ | |
339 | if (buffer_len(&stdout_buffer) > 0) | |
340 | FD_SET(fileno(stdout), writeset); | |
341 | if (buffer_len(&stderr_buffer) > 0) | |
342 | FD_SET(fileno(stderr), writeset); | |
343 | } else { | |
344 | FD_SET(connection_in, readset); | |
345 | } | |
346 | ||
347 | /* Add any selections by the channel mechanism. */ | |
348 | channel_prepare_select(readset, writeset); | |
349 | ||
350 | /* Select server connection if have data to write to the server. */ | |
351 | if (packet_have_data_to_write()) | |
352 | FD_SET(connection_out, writeset); | |
353 | ||
354 | /* move UP XXX */ | |
355 | /* Update maximum file descriptor number, if appropriate. */ | |
356 | if (channel_max_fd() > max_fd) | |
357 | max_fd = channel_max_fd(); | |
358 | ||
359 | /* | |
360 | * Wait for something to happen. This will suspend the process until | |
361 | * some selected descriptor can be read, written, or has some other | |
362 | * event pending. Note: if you want to implement SSH_MSG_IGNORE | |
363 | * messages to fool traffic analysis, this might be the place to do | |
364 | * it: just have a random timeout for the select, and send a random | |
365 | * SSH_MSG_IGNORE packet when the timeout expires. | |
366 | */ | |
367 | ||
368 | if (select(max_fd + 1, readset, writeset, NULL, NULL) < 0) { | |
369 | char buf[100]; | |
370 | /* Some systems fail to clear these automatically. */ | |
371 | FD_ZERO(readset); | |
372 | FD_ZERO(writeset); | |
373 | if (errno == EINTR) | |
374 | return; | |
375 | /* Note: we might still have data in the buffers. */ | |
376 | snprintf(buf, sizeof buf, "select: %s\r\n", strerror(errno)); | |
377 | buffer_append(&stderr_buffer, buf, strlen(buf)); | |
378 | stderr_bytes += strlen(buf); | |
379 | quit_pending = 1; | |
380 | } | |
381 | } | |
382 | ||
383 | void | |
384 | client_suspend_self() | |
385 | { | |
386 | struct winsize oldws, newws; | |
387 | ||
388 | /* Flush stdout and stderr buffers. */ | |
389 | if (buffer_len(&stdout_buffer) > 0) | |
390 | atomicio(write, fileno(stdout), buffer_ptr(&stdout_buffer), | |
391 | buffer_len(&stdout_buffer)); | |
392 | if (buffer_len(&stderr_buffer) > 0) | |
393 | atomicio(write, fileno(stderr), buffer_ptr(&stderr_buffer), | |
394 | buffer_len(&stderr_buffer)); | |
395 | ||
396 | leave_raw_mode(); | |
397 | ||
398 | /* | |
399 | * Free (and clear) the buffer to reduce the amount of data that gets | |
400 | * written to swap. | |
401 | */ | |
402 | buffer_free(&stdin_buffer); | |
403 | buffer_free(&stdout_buffer); | |
404 | buffer_free(&stderr_buffer); | |
405 | ||
406 | /* Save old window size. */ | |
407 | ioctl(fileno(stdin), TIOCGWINSZ, &oldws); | |
408 | ||
409 | /* Send the suspend signal to the program itself. */ | |
410 | kill(getpid(), SIGTSTP); | |
411 | ||
412 | /* Check if the window size has changed. */ | |
413 | if (ioctl(fileno(stdin), TIOCGWINSZ, &newws) >= 0 && | |
414 | (oldws.ws_row != newws.ws_row || | |
415 | oldws.ws_col != newws.ws_col || | |
416 | oldws.ws_xpixel != newws.ws_xpixel || | |
417 | oldws.ws_ypixel != newws.ws_ypixel)) | |
418 | received_window_change_signal = 1; | |
419 | ||
420 | /* OK, we have been continued by the user. Reinitialize buffers. */ | |
421 | buffer_init(&stdin_buffer); | |
422 | buffer_init(&stdout_buffer); | |
423 | buffer_init(&stderr_buffer); | |
424 | ||
425 | enter_raw_mode(); | |
426 | } | |
427 | ||
428 | void | |
429 | client_process_net_input(fd_set * readset) | |
430 | { | |
431 | int len; | |
432 | char buf[8192]; | |
433 | ||
434 | /* | |
435 | * Read input from the server, and add any such data to the buffer of | |
436 | * the packet subsystem. | |
437 | */ | |
438 | if (FD_ISSET(connection_in, readset)) { | |
439 | /* Read as much as possible. */ | |
440 | len = read(connection_in, buf, sizeof(buf)); | |
441 | /*debug("read connection_in len %d", len); XXX */ | |
442 | if (len == 0) { | |
443 | /* Received EOF. The remote host has closed the connection. */ | |
444 | snprintf(buf, sizeof buf, "Connection to %.300s closed by remote host.\r\n", | |
445 | host); | |
446 | buffer_append(&stderr_buffer, buf, strlen(buf)); | |
447 | stderr_bytes += strlen(buf); | |
448 | quit_pending = 1; | |
449 | return; | |
450 | } | |
451 | /* | |
452 | * There is a kernel bug on Solaris that causes select to | |
453 | * sometimes wake up even though there is no data available. | |
454 | */ | |
455 | if (len < 0 && errno == EAGAIN) | |
456 | len = 0; | |
457 | ||
458 | if (len < 0) { | |
459 | /* An error has encountered. Perhaps there is a network problem. */ | |
460 | snprintf(buf, sizeof buf, "Read from remote host %.300s: %.100s\r\n", | |
461 | host, strerror(errno)); | |
462 | buffer_append(&stderr_buffer, buf, strlen(buf)); | |
463 | stderr_bytes += strlen(buf); | |
464 | quit_pending = 1; | |
465 | return; | |
466 | } | |
467 | packet_process_incoming(buf, len); | |
468 | } | |
469 | } | |
470 | ||
471 | void | |
472 | client_process_input(fd_set * readset) | |
473 | { | |
474 | int len; | |
475 | pid_t pid; | |
476 | char buf[8192], *s; | |
477 | ||
478 | /* Read input from stdin. */ | |
479 | if (FD_ISSET(fileno(stdin), readset)) { | |
480 | /* Read as much as possible. */ | |
481 | len = read(fileno(stdin), buf, sizeof(buf)); | |
482 | if (len <= 0) { | |
483 | /* | |
484 | * Received EOF or error. They are treated | |
485 | * similarly, except that an error message is printed | |
486 | * if it was an error condition. | |
487 | */ | |
488 | if (len < 0) { | |
489 | snprintf(buf, sizeof buf, "read: %.100s\r\n", strerror(errno)); | |
490 | buffer_append(&stderr_buffer, buf, strlen(buf)); | |
491 | stderr_bytes += strlen(buf); | |
492 | } | |
493 | /* Mark that we have seen EOF. */ | |
494 | stdin_eof = 1; | |
495 | /* | |
496 | * Send an EOF message to the server unless there is | |
497 | * data in the buffer. If there is data in the | |
498 | * buffer, no message will be sent now. Code | |
499 | * elsewhere will send the EOF when the buffer | |
500 | * becomes empty if stdin_eof is set. | |
501 | */ | |
502 | if (buffer_len(&stdin_buffer) == 0) { | |
503 | packet_start(SSH_CMSG_EOF); | |
504 | packet_send(); | |
505 | } | |
506 | } else if (escape_char == -1) { | |
507 | /* | |
508 | * Normal successful read, and no escape character. | |
509 | * Just append the data to buffer. | |
510 | */ | |
511 | buffer_append(&stdin_buffer, buf, len); | |
512 | stdin_bytes += len; | |
513 | } else { | |
514 | /* | |
515 | * Normal, successful read. But we have an escape character | |
516 | * and have to process the characters one by one. | |
517 | */ | |
518 | unsigned int i; | |
519 | for (i = 0; i < len; i++) { | |
520 | unsigned char ch; | |
521 | /* Get one character at a time. */ | |
522 | ch = buf[i]; | |
523 | ||
524 | if (escape_pending) { | |
525 | /* We have previously seen an escape character. */ | |
526 | /* Clear the flag now. */ | |
527 | escape_pending = 0; | |
528 | /* Process the escaped character. */ | |
529 | switch (ch) { | |
530 | case '.': | |
531 | /* Terminate the connection. */ | |
532 | snprintf(buf, sizeof buf, "%c.\r\n", escape_char); | |
533 | buffer_append(&stderr_buffer, buf, strlen(buf)); | |
534 | stderr_bytes += strlen(buf); | |
535 | quit_pending = 1; | |
536 | return; | |
537 | ||
538 | case 'Z' - 64: | |
539 | /* Suspend the program. */ | |
540 | /* Print a message to that effect to the user. */ | |
541 | snprintf(buf, sizeof buf, "%c^Z\r\n", escape_char); | |
542 | buffer_append(&stderr_buffer, buf, strlen(buf)); | |
543 | stderr_bytes += strlen(buf); | |
544 | ||
545 | /* Restore terminal modes and suspend. */ | |
546 | client_suspend_self(); | |
547 | ||
548 | /* We have been continued. */ | |
549 | continue; | |
550 | ||
551 | case '&': | |
552 | /* | |
553 | * Detach the program (continue to serve connections, | |
554 | * but put in background and no more new connections). | |
555 | */ | |
556 | if (!stdin_eof) { | |
557 | /* | |
558 | * Sending SSH_CMSG_EOF alone does not always appear | |
559 | * to be enough. So we try to send an EOF character | |
560 | * first. | |
561 | */ | |
562 | packet_start(SSH_CMSG_STDIN_DATA); | |
563 | packet_put_string("\004", 1); | |
564 | packet_send(); | |
565 | /* Close stdin. */ | |
566 | stdin_eof = 1; | |
567 | if (buffer_len(&stdin_buffer) == 0) { | |
568 | packet_start(SSH_CMSG_EOF); | |
569 | packet_send(); | |
570 | } | |
571 | } | |
572 | /* Restore tty modes. */ | |
573 | leave_raw_mode(); | |
574 | ||
575 | /* Stop listening for new connections. */ | |
576 | channel_stop_listening(); | |
577 | ||
578 | printf("%c& [backgrounded]\n", escape_char); | |
579 | ||
580 | /* Fork into background. */ | |
581 | pid = fork(); | |
582 | if (pid < 0) { | |
583 | error("fork: %.100s", strerror(errno)); | |
584 | continue; | |
585 | } | |
586 | if (pid != 0) { /* This is the parent. */ | |
587 | /* The parent just exits. */ | |
588 | exit(0); | |
589 | } | |
590 | /* The child continues serving connections. */ | |
591 | continue; | |
592 | ||
593 | case '?': | |
594 | snprintf(buf, sizeof buf, | |
595 | "%c?\r\n\ | |
596 | Supported escape sequences:\r\n\ | |
597 | ~. - terminate connection\r\n\ | |
598 | ~^Z - suspend ssh\r\n\ | |
599 | ~# - list forwarded connections\r\n\ | |
600 | ~& - background ssh (when waiting for connections to terminate)\r\n\ | |
601 | ~? - this message\r\n\ | |
602 | ~~ - send the escape character by typing it twice\r\n\ | |
603 | (Note that escapes are only recognized immediately after newline.)\r\n", | |
604 | escape_char); | |
605 | buffer_append(&stderr_buffer, buf, strlen(buf)); | |
606 | continue; | |
607 | ||
608 | case '#': | |
609 | snprintf(buf, sizeof buf, "%c#\r\n", escape_char); | |
610 | buffer_append(&stderr_buffer, buf, strlen(buf)); | |
611 | s = channel_open_message(); | |
612 | buffer_append(&stderr_buffer, s, strlen(s)); | |
613 | xfree(s); | |
614 | continue; | |
615 | ||
616 | default: | |
617 | if (ch != escape_char) { | |
618 | /* | |
619 | * Escape character followed by non-special character. | |
620 | * Append both to the input buffer. | |
621 | */ | |
622 | buf[0] = escape_char; | |
623 | buf[1] = ch; | |
624 | buffer_append(&stdin_buffer, buf, 2); | |
625 | stdin_bytes += 2; | |
626 | continue; | |
627 | } | |
628 | /* | |
629 | * Note that escape character typed twice | |
630 | * falls through here; the latter gets processed | |
631 | * as a normal character below. | |
632 | */ | |
633 | break; | |
634 | } | |
635 | } else { | |
636 | /* | |
637 | * The previous character was not an escape char. Check if this | |
638 | * is an escape. | |
639 | */ | |
640 | if (last_was_cr && ch == escape_char) { | |
641 | /* It is. Set the flag and continue to next character. */ | |
642 | escape_pending = 1; | |
643 | continue; | |
644 | } | |
645 | } | |
646 | ||
647 | /* | |
648 | * Normal character. Record whether it was a newline, | |
649 | * and append it to the buffer. | |
650 | */ | |
651 | last_was_cr = (ch == '\r' || ch == '\n'); | |
652 | buf[0] = ch; | |
653 | buffer_append(&stdin_buffer, buf, 1); | |
654 | stdin_bytes += 1; | |
655 | continue; | |
656 | } | |
657 | } | |
658 | } | |
659 | } | |
660 | ||
661 | void | |
662 | client_process_output(fd_set * writeset) | |
663 | { | |
664 | int len; | |
665 | char buf[100]; | |
666 | ||
667 | /* Write buffered output to stdout. */ | |
668 | if (FD_ISSET(fileno(stdout), writeset)) { | |
669 | /* Write as much data as possible. */ | |
670 | len = write(fileno(stdout), buffer_ptr(&stdout_buffer), | |
671 | buffer_len(&stdout_buffer)); | |
672 | if (len <= 0) { | |
673 | if (errno == EAGAIN) | |
674 | len = 0; | |
675 | else { | |
676 | /* | |
677 | * An error or EOF was encountered. Put an | |
678 | * error message to stderr buffer. | |
679 | */ | |
680 | snprintf(buf, sizeof buf, "write stdout: %.50s\r\n", strerror(errno)); | |
681 | buffer_append(&stderr_buffer, buf, strlen(buf)); | |
682 | stderr_bytes += strlen(buf); | |
683 | quit_pending = 1; | |
684 | return; | |
685 | } | |
686 | } | |
687 | /* Consume printed data from the buffer. */ | |
688 | buffer_consume(&stdout_buffer, len); | |
689 | } | |
690 | /* Write buffered output to stderr. */ | |
691 | if (FD_ISSET(fileno(stderr), writeset)) { | |
692 | /* Write as much data as possible. */ | |
693 | len = write(fileno(stderr), buffer_ptr(&stderr_buffer), | |
694 | buffer_len(&stderr_buffer)); | |
695 | if (len <= 0) { | |
696 | if (errno == EAGAIN) | |
697 | len = 0; | |
698 | else { | |
699 | /* EOF or error, but can't even print error message. */ | |
700 | quit_pending = 1; | |
701 | return; | |
702 | } | |
703 | } | |
704 | /* Consume printed characters from the buffer. */ | |
705 | buffer_consume(&stderr_buffer, len); | |
706 | } | |
707 | } | |
708 | ||
709 | /* | |
710 | * Get packets from the connection input buffer, and process them as long as | |
711 | * there are packets available. | |
712 | * | |
713 | * Any unknown packets received during the actual | |
714 | * session cause the session to terminate. This is | |
715 | * intended to make debugging easier since no | |
716 | * confirmations are sent. Any compatible protocol | |
717 | * extensions must be negotiated during the | |
718 | * preparatory phase. | |
719 | */ | |
720 | ||
721 | void | |
722 | client_process_buffered_input_packets() | |
723 | { | |
724 | dispatch_run(DISPATCH_NONBLOCK, &quit_pending); | |
725 | } | |
726 | ||
727 | /* | |
728 | * Implements the interactive session with the server. This is called after | |
729 | * the user has been authenticated, and a command has been started on the | |
730 | * remote host. If escape_char != -1, it is the character used as an escape | |
731 | * character for terminating or suspending the session. | |
732 | */ | |
733 | ||
734 | int | |
735 | client_loop(int have_pty, int escape_char_arg) | |
736 | { | |
737 | extern Options options; | |
738 | double start_time, total_time; | |
739 | int len; | |
740 | char buf[100]; | |
741 | ||
742 | debug("Entering interactive session."); | |
743 | ||
744 | start_time = get_current_time(); | |
745 | ||
746 | /* Initialize variables. */ | |
747 | escape_pending = 0; | |
748 | last_was_cr = 1; | |
749 | exit_status = -1; | |
750 | stdin_eof = 0; | |
751 | buffer_high = 64 * 1024; | |
752 | connection_in = packet_get_connection_in(); | |
753 | connection_out = packet_get_connection_out(); | |
754 | max_fd = connection_in; | |
755 | if (connection_out > max_fd) | |
756 | max_fd = connection_out; | |
757 | stdin_bytes = 0; | |
758 | stdout_bytes = 0; | |
759 | stderr_bytes = 0; | |
760 | quit_pending = 0; | |
761 | escape_char = escape_char_arg; | |
762 | ||
763 | /* Initialize buffers. */ | |
764 | buffer_init(&stdin_buffer); | |
765 | buffer_init(&stdout_buffer); | |
766 | buffer_init(&stderr_buffer); | |
767 | ||
768 | client_init_dispatch(); | |
769 | ||
770 | /* Set signal handlers to restore non-blocking mode. */ | |
771 | signal(SIGINT, signal_handler); | |
772 | signal(SIGQUIT, signal_handler); | |
773 | signal(SIGTERM, signal_handler); | |
774 | signal(SIGPIPE, SIG_IGN); | |
775 | if (have_pty) | |
776 | signal(SIGWINCH, window_change_handler); | |
777 | ||
778 | if (have_pty) | |
779 | enter_raw_mode(); | |
780 | ||
781 | /* Check if we should immediately send of on stdin. */ | |
782 | if (!compat20) | |
783 | client_check_initial_eof_on_stdin(); | |
784 | ||
785 | /* Main loop of the client for the interactive session mode. */ | |
786 | while (!quit_pending) { | |
787 | fd_set readset, writeset; | |
788 | ||
789 | /* Process buffered packets sent by the server. */ | |
790 | client_process_buffered_input_packets(); | |
791 | ||
792 | if (compat20 && !channel_still_open()) { | |
793 | debug("!channel_still_open."); | |
794 | break; | |
795 | } | |
796 | ||
797 | /* | |
798 | * Make packets of buffered stdin data, and buffer them for | |
799 | * sending to the server. | |
800 | */ | |
801 | if (!compat20) | |
802 | client_make_packets_from_stdin_data(); | |
803 | ||
804 | /* | |
805 | * Make packets from buffered channel data, and buffer them | |
806 | * for sending to the server. | |
807 | */ | |
808 | if (packet_not_very_much_data_to_write()) | |
809 | channel_output_poll(); | |
810 | ||
811 | /* | |
812 | * Check if the window size has changed, and buffer a message | |
813 | * about it to the server if so. | |
814 | */ | |
815 | client_check_window_change(); | |
816 | ||
817 | if (quit_pending) | |
818 | break; | |
819 | ||
820 | /* | |
821 | * Wait until we have something to do (something becomes | |
822 | * available on one of the descriptors). | |
823 | */ | |
824 | client_wait_until_can_do_something(&readset, &writeset); | |
825 | ||
826 | if (quit_pending) | |
827 | break; | |
828 | ||
829 | /* Do channel operations. */ | |
830 | channel_after_select(&readset, &writeset); | |
831 | ||
832 | /* Buffer input from the connection. */ | |
833 | client_process_net_input(&readset); | |
834 | ||
835 | if (quit_pending) | |
836 | break; | |
837 | ||
838 | if (!compat20) { | |
839 | /* Buffer data from stdin */ | |
840 | client_process_input(&readset); | |
841 | /* | |
842 | * Process output to stdout and stderr. Output to | |
843 | * the connection is processed elsewhere (above). | |
844 | */ | |
845 | client_process_output(&writeset); | |
846 | } | |
847 | ||
848 | /* Send as much buffered packet data as possible to the sender. */ | |
849 | if (FD_ISSET(connection_out, &writeset)) | |
850 | packet_write_poll(); | |
851 | } | |
852 | ||
853 | /* Terminate the session. */ | |
854 | ||
855 | /* Stop watching for window change. */ | |
856 | if (have_pty) | |
857 | signal(SIGWINCH, SIG_DFL); | |
858 | ||
859 | /* Stop listening for connections. */ | |
860 | channel_stop_listening(); | |
861 | ||
862 | /* | |
863 | * In interactive mode (with pseudo tty) display a message indicating | |
864 | * that the connection has been closed. | |
865 | */ | |
866 | if (have_pty && options.log_level != SYSLOG_LEVEL_QUIET) { | |
867 | snprintf(buf, sizeof buf, "Connection to %.64s closed.\r\n", host); | |
868 | buffer_append(&stderr_buffer, buf, strlen(buf)); | |
869 | stderr_bytes += strlen(buf); | |
870 | } | |
871 | /* Output any buffered data for stdout. */ | |
872 | while (buffer_len(&stdout_buffer) > 0) { | |
873 | len = write(fileno(stdout), buffer_ptr(&stdout_buffer), | |
874 | buffer_len(&stdout_buffer)); | |
875 | if (len <= 0) { | |
876 | error("Write failed flushing stdout buffer."); | |
877 | break; | |
878 | } | |
879 | buffer_consume(&stdout_buffer, len); | |
880 | } | |
881 | ||
882 | /* Output any buffered data for stderr. */ | |
883 | while (buffer_len(&stderr_buffer) > 0) { | |
884 | len = write(fileno(stderr), buffer_ptr(&stderr_buffer), | |
885 | buffer_len(&stderr_buffer)); | |
886 | if (len <= 0) { | |
887 | error("Write failed flushing stderr buffer."); | |
888 | break; | |
889 | } | |
890 | buffer_consume(&stderr_buffer, len); | |
891 | } | |
892 | ||
893 | if (have_pty) | |
894 | leave_raw_mode(); | |
895 | ||
896 | /* Clear and free any buffers. */ | |
897 | memset(buf, 0, sizeof(buf)); | |
898 | buffer_free(&stdin_buffer); | |
899 | buffer_free(&stdout_buffer); | |
900 | buffer_free(&stderr_buffer); | |
901 | ||
902 | /* Report bytes transferred, and transfer rates. */ | |
903 | total_time = get_current_time() - start_time; | |
904 | debug("Transferred: stdin %lu, stdout %lu, stderr %lu bytes in %.1f seconds", | |
905 | stdin_bytes, stdout_bytes, stderr_bytes, total_time); | |
906 | if (total_time > 0) | |
907 | debug("Bytes per second: stdin %.1f, stdout %.1f, stderr %.1f", | |
908 | stdin_bytes / total_time, stdout_bytes / total_time, | |
909 | stderr_bytes / total_time); | |
910 | ||
911 | /* Return the exit status of the program. */ | |
912 | debug("Exit status %d", exit_status); | |
913 | return exit_status; | |
914 | } | |
915 | ||
916 | /*********/ | |
917 | ||
918 | void | |
919 | client_input_stdout_data(int type, int plen) | |
920 | { | |
921 | unsigned int data_len; | |
922 | char *data = packet_get_string(&data_len); | |
923 | packet_integrity_check(plen, 4 + data_len, type); | |
924 | buffer_append(&stdout_buffer, data, data_len); | |
925 | stdout_bytes += data_len; | |
926 | memset(data, 0, data_len); | |
927 | xfree(data); | |
928 | } | |
929 | void | |
930 | client_input_stderr_data(int type, int plen) | |
931 | { | |
932 | unsigned int data_len; | |
933 | char *data = packet_get_string(&data_len); | |
934 | packet_integrity_check(plen, 4 + data_len, type); | |
935 | buffer_append(&stderr_buffer, data, data_len); | |
936 | stdout_bytes += data_len; | |
937 | memset(data, 0, data_len); | |
938 | xfree(data); | |
939 | } | |
940 | void | |
941 | client_input_exit_status(int type, int plen) | |
942 | { | |
943 | packet_integrity_check(plen, 4, type); | |
944 | exit_status = packet_get_int(); | |
945 | /* Acknowledge the exit. */ | |
946 | packet_start(SSH_CMSG_EXIT_CONFIRMATION); | |
947 | packet_send(); | |
948 | /* | |
949 | * Must wait for packet to be sent since we are | |
950 | * exiting the loop. | |
951 | */ | |
952 | packet_write_wait(); | |
953 | /* Flag that we want to exit. */ | |
954 | quit_pending = 1; | |
955 | } | |
956 | ||
957 | /* XXXX move to generic input handler */ | |
958 | void | |
959 | client_input_channel_open(int type, int plen) | |
960 | { | |
961 | Channel *c = NULL; | |
962 | char *ctype; | |
963 | int id; | |
964 | unsigned int len; | |
965 | int rchan; | |
966 | int rmaxpack; | |
967 | int rwindow; | |
968 | ||
969 | ctype = packet_get_string(&len); | |
970 | rchan = packet_get_int(); | |
971 | rwindow = packet_get_int(); | |
972 | rmaxpack = packet_get_int(); | |
973 | ||
974 | debug("client_input_channel_open: ctype %s rchan %d win %d max %d", | |
975 | ctype, rchan, rwindow, rmaxpack); | |
976 | ||
977 | if (strcmp(ctype, "x11") == 0) { | |
978 | int sock; | |
979 | char *originator; | |
980 | int originator_port; | |
981 | originator = packet_get_string(NULL); | |
982 | if (datafellows & SSH_BUG_X11FWD) { | |
983 | debug("buggy server: x11 request w/o originator_port"); | |
984 | originator_port = 0; | |
985 | } else { | |
986 | originator_port = packet_get_int(); | |
987 | } | |
988 | packet_done(); | |
989 | /* XXX check permission */ | |
990 | xfree(originator); | |
991 | /* XXX move to channels.c */ | |
992 | sock = x11_connect_display(); | |
993 | if (sock >= 0) { | |
994 | id = channel_new("x11", SSH_CHANNEL_X11_OPEN, | |
995 | sock, sock, -1, 4*1024, 32*1024, 0, | |
996 | xstrdup("x11")); | |
997 | c = channel_lookup(id); | |
998 | } | |
999 | } | |
1000 | /* XXX duplicate : */ | |
1001 | if (c != NULL) { | |
1002 | debug("confirm %s", ctype); | |
1003 | c->remote_id = rchan; | |
1004 | c->remote_window = rwindow; | |
1005 | c->remote_maxpacket = rmaxpack; | |
1006 | ||
1007 | packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION); | |
1008 | packet_put_int(c->remote_id); | |
1009 | packet_put_int(c->self); | |
1010 | packet_put_int(c->local_window); | |
1011 | packet_put_int(c->local_maxpacket); | |
1012 | packet_send(); | |
1013 | } else { | |
1014 | debug("failure %s", ctype); | |
1015 | packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE); | |
1016 | packet_put_int(rchan); | |
1017 | packet_put_int(SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED); | |
1018 | packet_put_cstring("bla bla"); | |
1019 | packet_put_cstring(""); | |
1020 | packet_send(); | |
1021 | } | |
1022 | xfree(ctype); | |
1023 | } | |
1024 | ||
1025 | void | |
1026 | client_init_dispatch_20() | |
1027 | { | |
1028 | dispatch_init(&dispatch_protocol_error); | |
1029 | dispatch_set(SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose); | |
1030 | dispatch_set(SSH2_MSG_CHANNEL_DATA, &channel_input_data); | |
1031 | dispatch_set(SSH2_MSG_CHANNEL_EOF, &channel_input_ieof); | |
1032 | dispatch_set(SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data); | |
1033 | dispatch_set(SSH2_MSG_CHANNEL_OPEN, &client_input_channel_open); | |
1034 | dispatch_set(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation); | |
1035 | dispatch_set(SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure); | |
1036 | dispatch_set(SSH2_MSG_CHANNEL_REQUEST, &channel_input_channel_request); | |
1037 | dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust); | |
1038 | } | |
1039 | void | |
1040 | client_init_dispatch_13() | |
1041 | { | |
1042 | dispatch_init(NULL); | |
1043 | dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_close); | |
1044 | dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_close_confirmation); | |
1045 | dispatch_set(SSH_MSG_CHANNEL_DATA, &channel_input_data); | |
1046 | dispatch_set(SSH_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation); | |
1047 | dispatch_set(SSH_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure); | |
1048 | dispatch_set(SSH_MSG_PORT_OPEN, &channel_input_port_open); | |
1049 | dispatch_set(SSH_SMSG_AGENT_OPEN, &auth_input_open_request); | |
1050 | dispatch_set(SSH_SMSG_EXITSTATUS, &client_input_exit_status); | |
1051 | dispatch_set(SSH_SMSG_STDERR_DATA, &client_input_stderr_data); | |
1052 | dispatch_set(SSH_SMSG_STDOUT_DATA, &client_input_stdout_data); | |
1053 | dispatch_set(SSH_SMSG_X11_OPEN, &x11_input_open); | |
1054 | } | |
1055 | void | |
1056 | client_init_dispatch_15() | |
1057 | { | |
1058 | client_init_dispatch_13(); | |
1059 | dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_ieof); | |
1060 | dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, & channel_input_oclose); | |
1061 | } | |
1062 | void | |
1063 | client_init_dispatch() | |
1064 | { | |
1065 | if (compat20) | |
1066 | client_init_dispatch_20(); | |
1067 | else if (compat13) | |
1068 | client_init_dispatch_13(); | |
1069 | else | |
1070 | client_init_dispatch_15(); | |
1071 | } | |
1072 | ||
1073 | void | |
1074 | client_input_channel_req(int id, void *arg) | |
1075 | { | |
1076 | Channel *c = NULL; | |
1077 | unsigned int len; | |
1078 | int success = 0; | |
1079 | int reply; | |
1080 | char *rtype; | |
1081 | ||
1082 | rtype = packet_get_string(&len); | |
1083 | reply = packet_get_char(); | |
1084 | ||
1085 | debug("client_input_channel_req: rtype %s reply %d", rtype, reply); | |
1086 | ||
1087 | c = channel_lookup(id); | |
1088 | if (c == NULL) | |
1089 | fatal("session_input_channel_req: channel %d: bad channel", id); | |
1090 | ||
1091 | if (session_ident == -1) { | |
1092 | error("client_input_channel_req: no channel %d", id); | |
1093 | } else if (id != session_ident) { | |
1094 | error("client_input_channel_req: bad channel %d != %d", | |
1095 | id, session_ident); | |
1096 | } else if (strcmp(rtype, "exit-status") == 0) { | |
1097 | success = 1; | |
1098 | exit_status = packet_get_int(); | |
1099 | packet_done(); | |
1100 | } | |
1101 | if (reply) { | |
1102 | packet_start(success ? | |
1103 | SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE); | |
1104 | packet_put_int(c->remote_id); | |
1105 | packet_send(); | |
1106 | } | |
1107 | xfree(rtype); | |
1108 | } | |
1109 | ||
1110 | void | |
1111 | client_set_session_ident(int id) | |
1112 | { | |
1113 | debug("client_set_session_ident: id %d", id); | |
1114 | session_ident = id; | |
1115 | channel_register_callback(id, SSH2_MSG_CHANNEL_REQUEST, | |
1116 | client_input_channel_req, (void *)0); | |
1117 | } |