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Commit | Line | Data |
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8efc0c15 | 1 | /* |
5260325f | 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 | */ | |
8efc0c15 | 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" | |
6a17f9c2 | 25 | #include "readconf.h" |
8efc0c15 | 26 | |
8efc0c15 | 27 | /* Flag indicating that stdin should be redirected from /dev/null. */ |
28 | extern int stdin_null_flag; | |
29 | ||
aa3378df | 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 | */ | |
8efc0c15 | 35 | extern char *host; |
36 | ||
aa3378df | 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 | */ | |
8efc0c15 | 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 | ||
aa3378df | 48 | /* |
49 | * Flag indicating whether we are in raw mode. This is used by | |
50 | * enter_raw_mode and leave_raw_mode. | |
51 | */ | |
8efc0c15 | 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. */ | |
5260325f | 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). */ | |
8efc0c15 | 69 | static unsigned long stdin_bytes, stdout_bytes, stderr_bytes; |
5260325f | 70 | static int quit_pending; /* Set to non-zero to quit the client loop. */ |
71 | static int escape_char; /* Escape character. */ | |
8efc0c15 | 72 | |
aa3378df | 73 | /* Returns the user\'s terminal to normal mode if it had been put in raw mode. */ |
8efc0c15 | 74 | |
5260325f | 75 | void |
76 | leave_raw_mode() | |
8efc0c15 | 77 | { |
5260325f | 78 | if (!in_raw_mode) |
79 | return; | |
80 | in_raw_mode = 0; | |
81 | if (tcsetattr(fileno(stdin), TCSADRAIN, &saved_tio) < 0) | |
82 | perror("tcsetattr"); | |
8efc0c15 | 83 | |
5260325f | 84 | fatal_remove_cleanup((void (*) (void *)) leave_raw_mode, NULL); |
8efc0c15 | 85 | } |
86 | ||
87 | /* Puts the user\'s terminal in raw mode. */ | |
88 | ||
5260325f | 89 | void |
90 | enter_raw_mode() | |
8efc0c15 | 91 | { |
5260325f | 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); | |
8efc0c15 | 100 | #ifdef IEXTEN |
5260325f | 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 | } | |
8efc0c15 | 112 | |
113 | /* Restores stdin to blocking mode. */ | |
114 | ||
5260325f | 115 | void |
116 | leave_non_blocking() | |
8efc0c15 | 117 | { |
5260325f | 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 | } | |
8efc0c15 | 123 | } |
124 | ||
5260325f | 125 | /* Puts stdin terminal in non-blocking mode. */ |
126 | ||
127 | void | |
128 | enter_non_blocking() | |
8efc0c15 | 129 | { |
5260325f | 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); | |
8efc0c15 | 133 | } |
134 | ||
aa3378df | 135 | /* |
136 | * Signal handler for the window change signal (SIGWINCH). This just sets a | |
137 | * flag indicating that the window has changed. | |
138 | */ | |
8efc0c15 | 139 | |
5260325f | 140 | void |
141 | window_change_handler(int sig) | |
8efc0c15 | 142 | { |
5260325f | 143 | received_window_change_signal = 1; |
144 | signal(SIGWINCH, window_change_handler); | |
8efc0c15 | 145 | } |
146 | ||
aa3378df | 147 | /* |
148 | * Signal handler for signals that cause the program to terminate. These | |
149 | * signals must be trapped to restore terminal modes. | |
150 | */ | |
8efc0c15 | 151 | |
5260325f | 152 | void |
153 | signal_handler(int sig) | |
8efc0c15 | 154 | { |
5260325f | 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); | |
8efc0c15 | 162 | } |
163 | ||
aa3378df | 164 | /* |
165 | * Returns current time in seconds from Jan 1, 1970 with the maximum | |
166 | * available resolution. | |
167 | */ | |
8efc0c15 | 168 | |
5260325f | 169 | double |
170 | get_current_time() | |
8efc0c15 | 171 | { |
5260325f | 172 | struct timeval tv; |
173 | gettimeofday(&tv, NULL); | |
174 | return (double) tv.tv_sec + (double) tv.tv_usec / 1000000.0; | |
8efc0c15 | 175 | } |
176 | ||
aa3378df | 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 | */ | |
8efc0c15 | 182 | |
5260325f | 183 | void |
184 | client_check_initial_eof_on_stdin() | |
8efc0c15 | 185 | { |
5260325f | 186 | int len; |
187 | char buf[1]; | |
188 | ||
aa3378df | 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 | */ | |
5260325f | 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 { | |
5260325f | 204 | enter_non_blocking(); |
205 | ||
206 | /* Check for immediate EOF on stdin. */ | |
207 | len = read(fileno(stdin), buf, 1); | |
208 | if (len == 0) { | |
aa3378df | 209 | /* EOF. Record that we have seen it and send EOF to server. */ |
5260325f | 210 | debug("Sending eof."); |
211 | stdin_eof = 1; | |
212 | packet_start(SSH_CMSG_EOF); | |
213 | packet_send(); | |
214 | } else if (len > 0) { | |
aa3378df | 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 | */ | |
5260325f | 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 | } | |
5260325f | 227 | leave_non_blocking(); |
8efc0c15 | 228 | } |
8efc0c15 | 229 | } |
230 | ||
aa3378df | 231 | /* |
232 | * Get packets from the connection input buffer, and process them as long as | |
233 | * there are packets available. | |
234 | */ | |
8efc0c15 | 235 | |
5260325f | 236 | void |
237 | client_process_buffered_input_packets() | |
8efc0c15 | 238 | { |
5260325f | 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(); | |
aa3378df | 273 | /* |
274 | * Must wait for packet to be sent since we are | |
275 | * exiting the loop. | |
276 | */ | |
5260325f | 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: | |
aa3378df | 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 | */ | |
5260325f | 328 | packet_disconnect("Protocol error during session: type %d", |
329 | type); | |
330 | } | |
8efc0c15 | 331 | } |
8efc0c15 | 332 | } |
333 | ||
aa3378df | 334 | /* |
335 | * Make packets from buffered stdin data, and buffer them for sending to the | |
336 | * connection. | |
337 | */ | |
8efc0c15 | 338 | |
5260325f | 339 | void |
340 | client_make_packets_from_stdin_data() | |
8efc0c15 | 341 | { |
5260325f | 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 | } | |
8efc0c15 | 360 | } |
8efc0c15 | 361 | } |
362 | ||
aa3378df | 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 | */ | |
8efc0c15 | 369 | |
5260325f | 370 | void |
371 | client_check_window_change() | |
8efc0c15 | 372 | { |
5260325f | 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 | } | |
8efc0c15 | 390 | } |
8efc0c15 | 391 | } |
392 | ||
aa3378df | 393 | /* |
394 | * Waits until the client can do something (some data becomes available on | |
395 | * one of the file descriptors). | |
396 | */ | |
8efc0c15 | 397 | |
5260325f | 398 | void |
399 | client_wait_until_can_do_something(fd_set * readset, fd_set * writeset) | |
8efc0c15 | 400 | { |
5260325f | 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 | ||
aa3378df | 410 | /* |
411 | * Read from stdin, unless we have seen EOF or have very much | |
412 | * buffered data to send to the server. | |
413 | */ | |
5260325f | 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 | ||
aa3378df | 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 | */ | |
5260325f | 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 | } | |
8efc0c15 | 460 | } |
461 | ||
5260325f | 462 | void |
463 | client_suspend_self() | |
8efc0c15 | 464 | { |
5260325f | 465 | struct winsize oldws, newws; |
466 | ||
467 | /* Flush stdout and stderr buffers. */ | |
468 | if (buffer_len(&stdout_buffer) > 0) | |
469 | write(fileno(stdout), | |
470 | buffer_ptr(&stdout_buffer), | |
471 | buffer_len(&stdout_buffer)); | |
472 | if (buffer_len(&stderr_buffer) > 0) | |
473 | write(fileno(stderr), | |
474 | buffer_ptr(&stderr_buffer), | |
475 | buffer_len(&stderr_buffer)); | |
476 | ||
5260325f | 477 | leave_raw_mode(); |
478 | ||
aa3378df | 479 | /* |
480 | * Free (and clear) the buffer to reduce the amount of data that gets | |
481 | * written to swap. | |
482 | */ | |
5260325f | 483 | buffer_free(&stdin_buffer); |
484 | buffer_free(&stdout_buffer); | |
485 | buffer_free(&stderr_buffer); | |
486 | ||
487 | /* Save old window size. */ | |
488 | ioctl(fileno(stdin), TIOCGWINSZ, &oldws); | |
489 | ||
490 | /* Send the suspend signal to the program itself. */ | |
491 | kill(getpid(), SIGTSTP); | |
492 | ||
493 | /* Check if the window size has changed. */ | |
494 | if (ioctl(fileno(stdin), TIOCGWINSZ, &newws) >= 0 && | |
495 | (oldws.ws_row != newws.ws_row || | |
496 | oldws.ws_col != newws.ws_col || | |
497 | oldws.ws_xpixel != newws.ws_xpixel || | |
498 | oldws.ws_ypixel != newws.ws_ypixel)) | |
499 | received_window_change_signal = 1; | |
500 | ||
501 | /* OK, we have been continued by the user. Reinitialize buffers. */ | |
502 | buffer_init(&stdin_buffer); | |
503 | buffer_init(&stdout_buffer); | |
504 | buffer_init(&stderr_buffer); | |
505 | ||
5260325f | 506 | enter_raw_mode(); |
8efc0c15 | 507 | } |
508 | ||
5260325f | 509 | void |
510 | client_process_input(fd_set * readset) | |
8efc0c15 | 511 | { |
5260325f | 512 | int len, pid; |
513 | char buf[8192], *s; | |
514 | ||
aa3378df | 515 | /* |
516 | * Read input from the server, and add any such data to the buffer of | |
517 | * the packet subsystem. | |
518 | */ | |
5260325f | 519 | if (FD_ISSET(connection_in, readset)) { |
520 | /* Read as much as possible. */ | |
521 | len = read(connection_in, buf, sizeof(buf)); | |
522 | if (len == 0) { | |
523 | /* Received EOF. The remote host has closed the connection. */ | |
524 | snprintf(buf, sizeof buf, "Connection to %.300s closed by remote host.\r\n", | |
525 | host); | |
8efc0c15 | 526 | buffer_append(&stderr_buffer, buf, strlen(buf)); |
527 | stderr_bytes += strlen(buf); | |
528 | quit_pending = 1; | |
529 | return; | |
5260325f | 530 | } |
aa3378df | 531 | /* |
532 | * There is a kernel bug on Solaris that causes select to | |
533 | * sometimes wake up even though there is no data available. | |
534 | */ | |
5260325f | 535 | if (len < 0 && errno == EAGAIN) |
536 | len = 0; | |
537 | ||
538 | if (len < 0) { | |
539 | /* An error has encountered. Perhaps there is a network problem. */ | |
540 | snprintf(buf, sizeof buf, "Read from remote host %.300s: %.100s\r\n", | |
541 | host, strerror(errno)); | |
542 | buffer_append(&stderr_buffer, buf, strlen(buf)); | |
543 | stderr_bytes += strlen(buf); | |
544 | quit_pending = 1; | |
545 | return; | |
546 | } | |
547 | packet_process_incoming(buf, len); | |
548 | } | |
549 | /* Read input from stdin. */ | |
550 | if (FD_ISSET(fileno(stdin), readset)) { | |
551 | /* Read as much as possible. */ | |
552 | len = read(fileno(stdin), buf, sizeof(buf)); | |
553 | if (len <= 0) { | |
aa3378df | 554 | /* |
555 | * Received EOF or error. They are treated | |
556 | * similarly, except that an error message is printed | |
557 | * if it was an error condition. | |
558 | */ | |
5260325f | 559 | if (len < 0) { |
560 | snprintf(buf, sizeof buf, "read: %.100s\r\n", strerror(errno)); | |
561 | buffer_append(&stderr_buffer, buf, strlen(buf)); | |
562 | stderr_bytes += strlen(buf); | |
563 | } | |
564 | /* Mark that we have seen EOF. */ | |
565 | stdin_eof = 1; | |
aa3378df | 566 | /* |
567 | * Send an EOF message to the server unless there is | |
568 | * data in the buffer. If there is data in the | |
569 | * buffer, no message will be sent now. Code | |
570 | * elsewhere will send the EOF when the buffer | |
571 | * becomes empty if stdin_eof is set. | |
572 | */ | |
5260325f | 573 | if (buffer_len(&stdin_buffer) == 0) { |
8efc0c15 | 574 | packet_start(SSH_CMSG_EOF); |
575 | packet_send(); | |
5260325f | 576 | } |
577 | } else if (escape_char == -1) { | |
aa3378df | 578 | /* |
579 | * Normal successful read, and no escape character. | |
580 | * Just append the data to buffer. | |
581 | */ | |
5260325f | 582 | buffer_append(&stdin_buffer, buf, len); |
583 | stdin_bytes += len; | |
584 | } else { | |
aa3378df | 585 | /* |
586 | * Normal, successful read. But we have an escape character | |
587 | * and have to process the characters one by one. | |
588 | */ | |
5260325f | 589 | unsigned int i; |
590 | for (i = 0; i < len; i++) { | |
591 | unsigned char ch; | |
592 | /* Get one character at a time. */ | |
593 | ch = buf[i]; | |
594 | ||
5260325f | 595 | if (escape_pending) { |
596 | /* We have previously seen an escape character. */ | |
597 | /* Clear the flag now. */ | |
598 | escape_pending = 0; | |
599 | /* Process the escaped character. */ | |
600 | switch (ch) { | |
601 | case '.': | |
602 | /* Terminate the connection. */ | |
603 | snprintf(buf, sizeof buf, "%c.\r\n", escape_char); | |
604 | buffer_append(&stderr_buffer, buf, strlen(buf)); | |
605 | stderr_bytes += strlen(buf); | |
606 | quit_pending = 1; | |
607 | return; | |
608 | ||
609 | case 'Z' - 64: | |
610 | /* Suspend the program. */ | |
611 | /* Print a message to that effect to the user. */ | |
612 | snprintf(buf, sizeof buf, "%c^Z\r\n", escape_char); | |
613 | buffer_append(&stderr_buffer, buf, strlen(buf)); | |
614 | stderr_bytes += strlen(buf); | |
615 | ||
616 | /* Restore terminal modes and suspend. */ | |
617 | client_suspend_self(); | |
618 | ||
619 | /* We have been continued. */ | |
620 | continue; | |
621 | ||
622 | case '&': | |
aa3378df | 623 | /* |
624 | * Detach the program (continue to serve connections, | |
625 | * but put in background and no more new connections). | |
626 | */ | |
5260325f | 627 | if (!stdin_eof) { |
aa3378df | 628 | /* |
629 | * Sending SSH_CMSG_EOF alone does not always appear | |
630 | * to be enough. So we try to send an EOF character | |
631 | * first. | |
632 | */ | |
5260325f | 633 | packet_start(SSH_CMSG_STDIN_DATA); |
634 | packet_put_string("\004", 1); | |
635 | packet_send(); | |
636 | /* Close stdin. */ | |
637 | stdin_eof = 1; | |
638 | if (buffer_len(&stdin_buffer) == 0) { | |
639 | packet_start(SSH_CMSG_EOF); | |
640 | packet_send(); | |
641 | } | |
642 | } | |
643 | /* Restore tty modes. */ | |
644 | leave_raw_mode(); | |
645 | ||
646 | /* Stop listening for new connections. */ | |
647 | channel_stop_listening(); | |
648 | ||
649 | printf("%c& [backgrounded]\n", escape_char); | |
650 | ||
651 | /* Fork into background. */ | |
652 | pid = fork(); | |
653 | if (pid < 0) { | |
654 | error("fork: %.100s", strerror(errno)); | |
655 | continue; | |
656 | } | |
657 | if (pid != 0) { /* This is the parent. */ | |
658 | /* The parent just exits. */ | |
659 | exit(0); | |
660 | } | |
661 | /* The child continues serving connections. */ | |
662 | continue; | |
663 | ||
664 | case '?': | |
665 | snprintf(buf, sizeof buf, | |
666 | "%c?\r\n\ | |
8efc0c15 | 667 | Supported escape sequences:\r\n\ |
668 | ~. - terminate connection\r\n\ | |
669 | ~^Z - suspend ssh\r\n\ | |
670 | ~# - list forwarded connections\r\n\ | |
671 | ~& - background ssh (when waiting for connections to terminate)\r\n\ | |
672 | ~? - this message\r\n\ | |
673 | ~~ - send the escape character by typing it twice\r\n\ | |
674 | (Note that escapes are only recognized immediately after newline.)\r\n", | |
5260325f | 675 | escape_char); |
676 | buffer_append(&stderr_buffer, buf, strlen(buf)); | |
677 | continue; | |
678 | ||
679 | case '#': | |
680 | snprintf(buf, sizeof buf, "%c#\r\n", escape_char); | |
681 | buffer_append(&stderr_buffer, buf, strlen(buf)); | |
682 | s = channel_open_message(); | |
683 | buffer_append(&stderr_buffer, s, strlen(s)); | |
684 | xfree(s); | |
685 | continue; | |
686 | ||
687 | default: | |
688 | if (ch != escape_char) { | |
aa3378df | 689 | /* |
690 | * Escape character followed by non-special character. | |
691 | * Append both to the input buffer. | |
692 | */ | |
5260325f | 693 | buf[0] = escape_char; |
694 | buf[1] = ch; | |
695 | buffer_append(&stdin_buffer, buf, 2); | |
696 | stdin_bytes += 2; | |
697 | continue; | |
698 | } | |
aa3378df | 699 | /* |
700 | * Note that escape character typed twice | |
701 | * falls through here; the latter gets processed | |
702 | * as a normal character below. | |
703 | */ | |
5260325f | 704 | break; |
705 | } | |
706 | } else { | |
aa3378df | 707 | /* |
708 | * The previous character was not an escape char. Check if this | |
709 | * is an escape. | |
710 | */ | |
5260325f | 711 | if (last_was_cr && ch == escape_char) { |
712 | /* It is. Set the flag and continue to next character. */ | |
713 | escape_pending = 1; | |
714 | continue; | |
715 | } | |
716 | } | |
717 | ||
aa3378df | 718 | /* |
719 | * Normal character. Record whether it was a newline, | |
720 | * and append it to the buffer. | |
721 | */ | |
5260325f | 722 | last_was_cr = (ch == '\r' || ch == '\n'); |
723 | buf[0] = ch; | |
724 | buffer_append(&stdin_buffer, buf, 1); | |
725 | stdin_bytes += 1; | |
726 | continue; | |
727 | } | |
728 | } | |
729 | } | |
8efc0c15 | 730 | } |
731 | ||
5260325f | 732 | void |
733 | client_process_output(fd_set * writeset) | |
8efc0c15 | 734 | { |
5260325f | 735 | int len; |
736 | char buf[100]; | |
737 | ||
738 | /* Write buffered output to stdout. */ | |
739 | if (FD_ISSET(fileno(stdout), writeset)) { | |
740 | /* Write as much data as possible. */ | |
741 | len = write(fileno(stdout), buffer_ptr(&stdout_buffer), | |
742 | buffer_len(&stdout_buffer)); | |
743 | if (len <= 0) { | |
744 | if (errno == EAGAIN) | |
745 | len = 0; | |
746 | else { | |
aa3378df | 747 | /* |
748 | * An error or EOF was encountered. Put an | |
749 | * error message to stderr buffer. | |
750 | */ | |
5260325f | 751 | snprintf(buf, sizeof buf, "write stdout: %.50s\r\n", strerror(errno)); |
752 | buffer_append(&stderr_buffer, buf, strlen(buf)); | |
753 | stderr_bytes += strlen(buf); | |
754 | quit_pending = 1; | |
755 | return; | |
756 | } | |
757 | } | |
758 | /* Consume printed data from the buffer. */ | |
759 | buffer_consume(&stdout_buffer, len); | |
760 | } | |
761 | /* Write buffered output to stderr. */ | |
762 | if (FD_ISSET(fileno(stderr), writeset)) { | |
763 | /* Write as much data as possible. */ | |
764 | len = write(fileno(stderr), buffer_ptr(&stderr_buffer), | |
765 | buffer_len(&stderr_buffer)); | |
766 | if (len <= 0) { | |
767 | if (errno == EAGAIN) | |
768 | len = 0; | |
769 | else { | |
aa3378df | 770 | /* EOF or error, but can't even print error message. */ |
5260325f | 771 | quit_pending = 1; |
772 | return; | |
773 | } | |
774 | } | |
775 | /* Consume printed characters from the buffer. */ | |
776 | buffer_consume(&stderr_buffer, len); | |
8efc0c15 | 777 | } |
8efc0c15 | 778 | } |
779 | ||
aa3378df | 780 | /* |
781 | * Implements the interactive session with the server. This is called after | |
782 | * the user has been authenticated, and a command has been started on the | |
783 | * remote host. If escape_char != -1, it is the character used as an escape | |
784 | * character for terminating or suspending the session. | |
785 | */ | |
8efc0c15 | 786 | |
5260325f | 787 | int |
788 | client_loop(int have_pty, int escape_char_arg) | |
8efc0c15 | 789 | { |
5260325f | 790 | extern Options options; |
791 | double start_time, total_time; | |
792 | int len; | |
793 | char buf[100]; | |
794 | ||
795 | debug("Entering interactive session."); | |
796 | ||
797 | start_time = get_current_time(); | |
798 | ||
799 | /* Initialize variables. */ | |
800 | escape_pending = 0; | |
801 | last_was_cr = 1; | |
802 | exit_status = -1; | |
803 | stdin_eof = 0; | |
804 | buffer_high = 64 * 1024; | |
805 | connection_in = packet_get_connection_in(); | |
806 | connection_out = packet_get_connection_out(); | |
807 | max_fd = connection_in; | |
808 | if (connection_out > max_fd) | |
809 | max_fd = connection_out; | |
810 | stdin_bytes = 0; | |
811 | stdout_bytes = 0; | |
812 | stderr_bytes = 0; | |
813 | quit_pending = 0; | |
814 | escape_char = escape_char_arg; | |
815 | ||
816 | /* Initialize buffers. */ | |
817 | buffer_init(&stdin_buffer); | |
818 | buffer_init(&stdout_buffer); | |
819 | buffer_init(&stderr_buffer); | |
820 | ||
821 | /* Set signal handlers to restore non-blocking mode. */ | |
822 | signal(SIGINT, signal_handler); | |
823 | signal(SIGQUIT, signal_handler); | |
824 | signal(SIGTERM, signal_handler); | |
825 | signal(SIGPIPE, SIG_IGN); | |
826 | if (have_pty) | |
827 | signal(SIGWINCH, window_change_handler); | |
828 | ||
5260325f | 829 | if (have_pty) |
830 | enter_raw_mode(); | |
831 | ||
832 | /* Check if we should immediately send of on stdin. */ | |
833 | client_check_initial_eof_on_stdin(); | |
834 | ||
835 | /* Main loop of the client for the interactive session mode. */ | |
836 | while (!quit_pending) { | |
837 | fd_set readset, writeset; | |
838 | ||
aa3378df | 839 | /* Process buffered packets sent by the server. */ |
5260325f | 840 | client_process_buffered_input_packets(); |
841 | ||
aa3378df | 842 | /* |
843 | * Make packets of buffered stdin data, and buffer them for | |
844 | * sending to the server. | |
845 | */ | |
5260325f | 846 | client_make_packets_from_stdin_data(); |
847 | ||
aa3378df | 848 | /* |
849 | * Make packets from buffered channel data, and buffer them | |
850 | * for sending to the server. | |
851 | */ | |
5260325f | 852 | if (packet_not_very_much_data_to_write()) |
853 | channel_output_poll(); | |
854 | ||
aa3378df | 855 | /* |
856 | * Check if the window size has changed, and buffer a message | |
857 | * about it to the server if so. | |
858 | */ | |
5260325f | 859 | client_check_window_change(); |
860 | ||
861 | if (quit_pending) | |
862 | break; | |
863 | ||
aa3378df | 864 | /* |
865 | * Wait until we have something to do (something becomes | |
866 | * available on one of the descriptors). | |
867 | */ | |
5260325f | 868 | client_wait_until_can_do_something(&readset, &writeset); |
869 | ||
870 | if (quit_pending) | |
871 | break; | |
872 | ||
873 | /* Do channel operations. */ | |
874 | channel_after_select(&readset, &writeset); | |
875 | ||
aa3378df | 876 | /* |
877 | * Process input from the connection and from stdin. Buffer | |
878 | * any data that is available. | |
879 | */ | |
5260325f | 880 | client_process_input(&readset); |
881 | ||
aa3378df | 882 | /* |
883 | * Process output to stdout and stderr. Output to the | |
884 | * connection is processed elsewhere (above). | |
885 | */ | |
5260325f | 886 | client_process_output(&writeset); |
887 | ||
aa3378df | 888 | /* Send as much buffered packet data as possible to the sender. */ |
5260325f | 889 | if (FD_ISSET(connection_out, &writeset)) |
890 | packet_write_poll(); | |
891 | } | |
892 | ||
893 | /* Terminate the session. */ | |
894 | ||
895 | /* Stop watching for window change. */ | |
896 | if (have_pty) | |
897 | signal(SIGWINCH, SIG_DFL); | |
898 | ||
899 | /* Stop listening for connections. */ | |
900 | channel_stop_listening(); | |
901 | ||
aa3378df | 902 | /* |
903 | * In interactive mode (with pseudo tty) display a message indicating | |
904 | * that the connection has been closed. | |
905 | */ | |
5260325f | 906 | if (have_pty && options.log_level != SYSLOG_LEVEL_QUIET) { |
907 | snprintf(buf, sizeof buf, "Connection to %.64s closed.\r\n", host); | |
908 | buffer_append(&stderr_buffer, buf, strlen(buf)); | |
909 | stderr_bytes += strlen(buf); | |
8efc0c15 | 910 | } |
5260325f | 911 | /* Output any buffered data for stdout. */ |
912 | while (buffer_len(&stdout_buffer) > 0) { | |
913 | len = write(fileno(stdout), buffer_ptr(&stdout_buffer), | |
914 | buffer_len(&stdout_buffer)); | |
915 | if (len <= 0) { | |
916 | error("Write failed flushing stdout buffer."); | |
917 | break; | |
918 | } | |
919 | buffer_consume(&stdout_buffer, len); | |
8efc0c15 | 920 | } |
5260325f | 921 | |
922 | /* Output any buffered data for stderr. */ | |
923 | while (buffer_len(&stderr_buffer) > 0) { | |
924 | len = write(fileno(stderr), buffer_ptr(&stderr_buffer), | |
925 | buffer_len(&stderr_buffer)); | |
926 | if (len <= 0) { | |
927 | error("Write failed flushing stderr buffer."); | |
928 | break; | |
929 | } | |
930 | buffer_consume(&stderr_buffer, len); | |
931 | } | |
932 | ||
5260325f | 933 | if (have_pty) |
934 | leave_raw_mode(); | |
935 | ||
936 | /* Clear and free any buffers. */ | |
937 | memset(buf, 0, sizeof(buf)); | |
938 | buffer_free(&stdin_buffer); | |
939 | buffer_free(&stdout_buffer); | |
940 | buffer_free(&stderr_buffer); | |
941 | ||
942 | /* Report bytes transferred, and transfer rates. */ | |
943 | total_time = get_current_time() - start_time; | |
944 | debug("Transferred: stdin %lu, stdout %lu, stderr %lu bytes in %.1f seconds", | |
945 | stdin_bytes, stdout_bytes, stderr_bytes, total_time); | |
946 | if (total_time > 0) | |
947 | debug("Bytes per second: stdin %.1f, stdout %.1f, stderr %.1f", | |
948 | stdin_bytes / total_time, stdout_bytes / total_time, | |
949 | stderr_bytes / total_time); | |
950 | ||
951 | /* Return the exit status of the program. */ | |
952 | debug("Exit status %d", exit_status); | |
953 | return exit_status; | |
8efc0c15 | 954 | } |