Annotation of src/usr.bin/ssh/clientloop.c, Revision 1.18
1.1 deraadt 1: /*
1.12 deraadt 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: *
1.16 markus 15: * SSH2 support added by Markus Friedl.
1.12 deraadt 16: */
1.1 deraadt 17:
18: #include "includes.h"
1.18 ! markus 19: RCSID("$Id: clientloop.c,v 1.17 2000/04/04 17:29:46 markus Exp $");
1.1 deraadt 20:
21: #include "xmalloc.h"
22: #include "ssh.h"
23: #include "packet.h"
24: #include "buffer.h"
25: #include "authfd.h"
1.8 markus 26: #include "readconf.h"
1.1 deraadt 27:
1.16 markus 28: #include "ssh2.h"
1.15 markus 29: #include "compat.h"
30: #include "channels.h"
31: #include "dispatch.h"
32:
33:
1.1 deraadt 34: /* Flag indicating that stdin should be redirected from /dev/null. */
35: extern int stdin_null_flag;
36:
1.13 markus 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: */
1.1 deraadt 42: extern char *host;
43:
1.13 markus 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: */
1.1 deraadt 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:
1.13 markus 55: /*
56: * Flag indicating whether we are in raw mode. This is used by
57: * enter_raw_mode and leave_raw_mode.
58: */
1.1 deraadt 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. */
1.11 markus 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). */
1.1 deraadt 76: static unsigned long stdin_bytes, stdout_bytes, stderr_bytes;
1.11 markus 77: static int quit_pending; /* Set to non-zero to quit the client loop. */
78: static int escape_char; /* Escape character. */
1.1 deraadt 79:
1.16 markus 80:
81: void client_init_dispatch(void);
82: int session_ident = -1;
83:
1.13 markus 84: /* Returns the user\'s terminal to normal mode if it had been put in raw mode. */
1.1 deraadt 85:
1.11 markus 86: void
87: leave_raw_mode()
1.1 deraadt 88: {
1.11 markus 89: if (!in_raw_mode)
90: return;
91: in_raw_mode = 0;
92: if (tcsetattr(fileno(stdin), TCSADRAIN, &saved_tio) < 0)
93: perror("tcsetattr");
1.1 deraadt 94:
1.11 markus 95: fatal_remove_cleanup((void (*) (void *)) leave_raw_mode, NULL);
1.1 deraadt 96: }
97:
98: /* Puts the user\'s terminal in raw mode. */
99:
1.11 markus 100: void
101: enter_raw_mode()
1.1 deraadt 102: {
1.11 markus 103: struct termios tio;
1.1 deraadt 104:
1.11 markus 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);
1.1 deraadt 111: #ifdef IEXTEN
1.11 markus 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;
1.1 deraadt 120:
1.11 markus 121: fatal_add_cleanup((void (*) (void *)) leave_raw_mode, NULL);
122: }
1.1 deraadt 123:
124: /* Restores stdin to blocking mode. */
125:
1.11 markus 126: void
127: leave_non_blocking()
1.1 deraadt 128: {
1.11 markus 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: }
1.1 deraadt 134: }
135:
1.11 markus 136: /* Puts stdin terminal in non-blocking mode. */
137:
138: void
139: enter_non_blocking()
1.1 deraadt 140: {
1.11 markus 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);
1.1 deraadt 144: }
145:
1.13 markus 146: /*
147: * Signal handler for the window change signal (SIGWINCH). This just sets a
148: * flag indicating that the window has changed.
149: */
1.1 deraadt 150:
1.11 markus 151: void
152: window_change_handler(int sig)
1.1 deraadt 153: {
1.11 markus 154: received_window_change_signal = 1;
155: signal(SIGWINCH, window_change_handler);
1.1 deraadt 156: }
157:
1.13 markus 158: /*
159: * Signal handler for signals that cause the program to terminate. These
160: * signals must be trapped to restore terminal modes.
161: */
1.1 deraadt 162:
1.11 markus 163: void
164: signal_handler(int sig)
1.1 deraadt 165: {
1.11 markus 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);
1.1 deraadt 173: }
174:
1.13 markus 175: /*
176: * Returns current time in seconds from Jan 1, 1970 with the maximum
177: * available resolution.
178: */
1.1 deraadt 179:
1.11 markus 180: double
181: get_current_time()
1.1 deraadt 182: {
1.11 markus 183: struct timeval tv;
184: gettimeofday(&tv, NULL);
185: return (double) tv.tv_sec + (double) tv.tv_usec / 1000000.0;
1.1 deraadt 186: }
187:
1.13 markus 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: */
1.1 deraadt 193:
1.11 markus 194: void
195: client_check_initial_eof_on_stdin()
1.1 deraadt 196: {
1.11 markus 197: int len;
198: char buf[1];
1.1 deraadt 199:
1.13 markus 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: */
1.11 markus 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) {
1.13 markus 220: /* EOF. Record that we have seen it and send EOF to server. */
1.11 markus 221: debug("Sending eof.");
222: stdin_eof = 1;
223: packet_start(SSH_CMSG_EOF);
224: packet_send();
225: } else if (len > 0) {
1.13 markus 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: */
1.11 markus 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: }
1.1 deraadt 240: }
241:
242:
1.13 markus 243: /*
244: * Make packets from buffered stdin data, and buffer them for sending to the
245: * connection.
246: */
1.1 deraadt 247:
1.11 markus 248: void
249: client_make_packets_from_stdin_data()
1.1 deraadt 250: {
1.11 markus 251: unsigned int len;
1.1 deraadt 252:
1.11 markus 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: }
1.1 deraadt 269: }
270: }
271:
1.13 markus 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: */
1.1 deraadt 278:
1.11 markus 279: void
280: client_check_window_change()
1.1 deraadt 281: {
1.16 markus 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();
1.1 deraadt 308: }
309: }
310:
1.13 markus 311: /*
312: * Waits until the client can do something (some data becomes available on
313: * one of the file descriptors).
314: */
1.1 deraadt 315:
1.11 markus 316: void
317: client_wait_until_can_do_something(fd_set * readset, fd_set * writeset)
318: {
1.16 markus 319: /*debug("client_wait_until_can_do_something"); */
320:
1.11 markus 321: /* Initialize select masks. */
322: FD_ZERO(readset);
1.17 markus 323: FD_ZERO(writeset);
1.11 markus 324:
1.16 markus 325: if (!compat20) {
1.17 markus 326: /* Read from the connection, unless our buffers are full. */
1.16 markus 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);
1.17 markus 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);
1.16 markus 343: } else {
1.11 markus 344: FD_SET(connection_in, readset);
1.16 markus 345: }
1.11 markus 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:
1.16 markus 354: /* move UP XXX */
1.11 markus 355: /* Update maximum file descriptor number, if appropriate. */
356: if (channel_max_fd() > max_fd)
357: max_fd = channel_max_fd();
358:
1.13 markus 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: */
1.11 markus 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()
1.1 deraadt 385: {
1.11 markus 386: struct winsize oldws, newws;
387:
388: /* Flush stdout and stderr buffers. */
389: if (buffer_len(&stdout_buffer) > 0)
1.14 deraadt 390: atomicio(write, fileno(stdout), buffer_ptr(&stdout_buffer),
391: buffer_len(&stdout_buffer));
1.11 markus 392: if (buffer_len(&stderr_buffer) > 0)
1.14 deraadt 393: atomicio(write, fileno(stderr), buffer_ptr(&stderr_buffer),
394: buffer_len(&stderr_buffer));
1.11 markus 395:
396: leave_raw_mode();
397:
1.13 markus 398: /*
399: * Free (and clear) the buffer to reduce the amount of data that gets
400: * written to swap.
401: */
1.11 markus 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
1.17 markus 429: client_process_net_input(fd_set * readset)
1.11 markus 430: {
1.17 markus 431: int len;
432: char buf[8192];
1.11 markus 433:
1.13 markus 434: /*
435: * Read input from the server, and add any such data to the buffer of
436: * the packet subsystem.
437: */
1.11 markus 438: if (FD_ISSET(connection_in, readset)) {
439: /* Read as much as possible. */
440: len = read(connection_in, buf, sizeof(buf));
1.16 markus 441: /*debug("read connection_in len %d", len); XXX */
1.11 markus 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);
1.1 deraadt 446: buffer_append(&stderr_buffer, buf, strlen(buf));
447: stderr_bytes += strlen(buf);
448: quit_pending = 1;
449: return;
1.11 markus 450: }
1.13 markus 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: */
1.11 markus 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: }
1.17 markus 469: }
1.16 markus 470:
1.17 markus 471: void
472: client_process_input(fd_set * readset)
473: {
474: int len, pid;
475: char buf[8192], *s;
1.16 markus 476:
1.11 markus 477: /* Read input from stdin. */
478: if (FD_ISSET(fileno(stdin), readset)) {
479: /* Read as much as possible. */
480: len = read(fileno(stdin), buf, sizeof(buf));
481: if (len <= 0) {
1.13 markus 482: /*
483: * Received EOF or error. They are treated
484: * similarly, except that an error message is printed
485: * if it was an error condition.
486: */
1.11 markus 487: if (len < 0) {
488: snprintf(buf, sizeof buf, "read: %.100s\r\n", strerror(errno));
489: buffer_append(&stderr_buffer, buf, strlen(buf));
490: stderr_bytes += strlen(buf);
491: }
492: /* Mark that we have seen EOF. */
493: stdin_eof = 1;
1.13 markus 494: /*
495: * Send an EOF message to the server unless there is
496: * data in the buffer. If there is data in the
497: * buffer, no message will be sent now. Code
498: * elsewhere will send the EOF when the buffer
499: * becomes empty if stdin_eof is set.
500: */
1.11 markus 501: if (buffer_len(&stdin_buffer) == 0) {
1.1 deraadt 502: packet_start(SSH_CMSG_EOF);
503: packet_send();
1.11 markus 504: }
505: } else if (escape_char == -1) {
1.13 markus 506: /*
507: * Normal successful read, and no escape character.
508: * Just append the data to buffer.
509: */
1.11 markus 510: buffer_append(&stdin_buffer, buf, len);
511: stdin_bytes += len;
512: } else {
1.13 markus 513: /*
514: * Normal, successful read. But we have an escape character
515: * and have to process the characters one by one.
516: */
1.11 markus 517: unsigned int i;
518: for (i = 0; i < len; i++) {
519: unsigned char ch;
520: /* Get one character at a time. */
521: ch = buf[i];
522:
523: if (escape_pending) {
524: /* We have previously seen an escape character. */
525: /* Clear the flag now. */
526: escape_pending = 0;
527: /* Process the escaped character. */
528: switch (ch) {
529: case '.':
530: /* Terminate the connection. */
531: snprintf(buf, sizeof buf, "%c.\r\n", escape_char);
532: buffer_append(&stderr_buffer, buf, strlen(buf));
533: stderr_bytes += strlen(buf);
534: quit_pending = 1;
535: return;
536:
537: case 'Z' - 64:
538: /* Suspend the program. */
539: /* Print a message to that effect to the user. */
540: snprintf(buf, sizeof buf, "%c^Z\r\n", escape_char);
541: buffer_append(&stderr_buffer, buf, strlen(buf));
542: stderr_bytes += strlen(buf);
543:
544: /* Restore terminal modes and suspend. */
545: client_suspend_self();
546:
547: /* We have been continued. */
548: continue;
549:
550: case '&':
1.13 markus 551: /*
552: * Detach the program (continue to serve connections,
553: * but put in background and no more new connections).
554: */
1.11 markus 555: if (!stdin_eof) {
1.13 markus 556: /*
557: * Sending SSH_CMSG_EOF alone does not always appear
558: * to be enough. So we try to send an EOF character
559: * first.
560: */
1.11 markus 561: packet_start(SSH_CMSG_STDIN_DATA);
562: packet_put_string("\004", 1);
563: packet_send();
564: /* Close stdin. */
565: stdin_eof = 1;
566: if (buffer_len(&stdin_buffer) == 0) {
567: packet_start(SSH_CMSG_EOF);
568: packet_send();
569: }
570: }
571: /* Restore tty modes. */
572: leave_raw_mode();
573:
574: /* Stop listening for new connections. */
575: channel_stop_listening();
576:
577: printf("%c& [backgrounded]\n", escape_char);
578:
579: /* Fork into background. */
580: pid = fork();
581: if (pid < 0) {
582: error("fork: %.100s", strerror(errno));
583: continue;
584: }
585: if (pid != 0) { /* This is the parent. */
586: /* The parent just exits. */
587: exit(0);
588: }
589: /* The child continues serving connections. */
590: continue;
591:
592: case '?':
593: snprintf(buf, sizeof buf,
594: "%c?\r\n\
1.1 deraadt 595: Supported escape sequences:\r\n\
596: ~. - terminate connection\r\n\
597: ~^Z - suspend ssh\r\n\
598: ~# - list forwarded connections\r\n\
599: ~& - background ssh (when waiting for connections to terminate)\r\n\
600: ~? - this message\r\n\
601: ~~ - send the escape character by typing it twice\r\n\
602: (Note that escapes are only recognized immediately after newline.)\r\n",
1.11 markus 603: escape_char);
604: buffer_append(&stderr_buffer, buf, strlen(buf));
605: continue;
606:
607: case '#':
608: snprintf(buf, sizeof buf, "%c#\r\n", escape_char);
609: buffer_append(&stderr_buffer, buf, strlen(buf));
610: s = channel_open_message();
611: buffer_append(&stderr_buffer, s, strlen(s));
612: xfree(s);
613: continue;
614:
615: default:
616: if (ch != escape_char) {
1.13 markus 617: /*
618: * Escape character followed by non-special character.
619: * Append both to the input buffer.
620: */
1.11 markus 621: buf[0] = escape_char;
622: buf[1] = ch;
623: buffer_append(&stdin_buffer, buf, 2);
624: stdin_bytes += 2;
625: continue;
626: }
1.13 markus 627: /*
628: * Note that escape character typed twice
629: * falls through here; the latter gets processed
630: * as a normal character below.
631: */
1.11 markus 632: break;
633: }
634: } else {
1.13 markus 635: /*
636: * The previous character was not an escape char. Check if this
637: * is an escape.
638: */
1.11 markus 639: if (last_was_cr && ch == escape_char) {
640: /* It is. Set the flag and continue to next character. */
641: escape_pending = 1;
642: continue;
643: }
644: }
645:
1.13 markus 646: /*
647: * Normal character. Record whether it was a newline,
648: * and append it to the buffer.
649: */
1.11 markus 650: last_was_cr = (ch == '\r' || ch == '\n');
651: buf[0] = ch;
652: buffer_append(&stdin_buffer, buf, 1);
653: stdin_bytes += 1;
654: continue;
655: }
656: }
657: }
658: }
659:
660: void
661: client_process_output(fd_set * writeset)
662: {
663: int len;
664: char buf[100];
1.1 deraadt 665:
1.11 markus 666: /* Write buffered output to stdout. */
667: if (FD_ISSET(fileno(stdout), writeset)) {
668: /* Write as much data as possible. */
669: len = write(fileno(stdout), buffer_ptr(&stdout_buffer),
1.14 deraadt 670: buffer_len(&stdout_buffer));
1.11 markus 671: if (len <= 0) {
672: if (errno == EAGAIN)
673: len = 0;
674: else {
1.13 markus 675: /*
676: * An error or EOF was encountered. Put an
677: * error message to stderr buffer.
678: */
1.11 markus 679: snprintf(buf, sizeof buf, "write stdout: %.50s\r\n", strerror(errno));
680: buffer_append(&stderr_buffer, buf, strlen(buf));
681: stderr_bytes += strlen(buf);
682: quit_pending = 1;
683: return;
684: }
685: }
686: /* Consume printed data from the buffer. */
687: buffer_consume(&stdout_buffer, len);
688: }
689: /* Write buffered output to stderr. */
690: if (FD_ISSET(fileno(stderr), writeset)) {
691: /* Write as much data as possible. */
692: len = write(fileno(stderr), buffer_ptr(&stderr_buffer),
1.14 deraadt 693: buffer_len(&stderr_buffer));
1.11 markus 694: if (len <= 0) {
695: if (errno == EAGAIN)
696: len = 0;
697: else {
1.13 markus 698: /* EOF or error, but can't even print error message. */
1.11 markus 699: quit_pending = 1;
700: return;
701: }
702: }
703: /* Consume printed characters from the buffer. */
704: buffer_consume(&stderr_buffer, len);
705: }
1.1 deraadt 706: }
707:
1.13 markus 708: /*
1.15 markus 709: * Get packets from the connection input buffer, and process them as long as
710: * there are packets available.
711: *
712: * Any unknown packets received during the actual
713: * session cause the session to terminate. This is
714: * intended to make debugging easier since no
715: * confirmations are sent. Any compatible protocol
716: * extensions must be negotiated during the
717: * preparatory phase.
718: */
719:
720: void
721: client_process_buffered_input_packets()
722: {
723: dispatch_run(DISPATCH_NONBLOCK, &quit_pending);
724: }
725:
726: /*
1.13 markus 727: * Implements the interactive session with the server. This is called after
728: * the user has been authenticated, and a command has been started on the
729: * remote host. If escape_char != -1, it is the character used as an escape
730: * character for terminating or suspending the session.
731: */
1.1 deraadt 732:
1.11 markus 733: int
734: client_loop(int have_pty, int escape_char_arg)
1.1 deraadt 735: {
1.11 markus 736: extern Options options;
737: double start_time, total_time;
738: int len;
739: char buf[100];
740:
741: debug("Entering interactive session.");
742:
743: start_time = get_current_time();
744:
745: /* Initialize variables. */
746: escape_pending = 0;
747: last_was_cr = 1;
748: exit_status = -1;
749: stdin_eof = 0;
750: buffer_high = 64 * 1024;
751: connection_in = packet_get_connection_in();
752: connection_out = packet_get_connection_out();
753: max_fd = connection_in;
754: if (connection_out > max_fd)
755: max_fd = connection_out;
756: stdin_bytes = 0;
757: stdout_bytes = 0;
758: stderr_bytes = 0;
759: quit_pending = 0;
760: escape_char = escape_char_arg;
761:
762: /* Initialize buffers. */
763: buffer_init(&stdin_buffer);
764: buffer_init(&stdout_buffer);
765: buffer_init(&stderr_buffer);
766:
1.15 markus 767: client_init_dispatch();
768:
1.11 markus 769: /* Set signal handlers to restore non-blocking mode. */
770: signal(SIGINT, signal_handler);
771: signal(SIGQUIT, signal_handler);
772: signal(SIGTERM, signal_handler);
773: signal(SIGPIPE, SIG_IGN);
774: if (have_pty)
775: signal(SIGWINCH, window_change_handler);
776:
777: if (have_pty)
778: enter_raw_mode();
779:
780: /* Check if we should immediately send of on stdin. */
1.17 markus 781: if (!compat20)
1.16 markus 782: client_check_initial_eof_on_stdin();
1.11 markus 783:
784: /* Main loop of the client for the interactive session mode. */
785: while (!quit_pending) {
786: fd_set readset, writeset;
787:
1.13 markus 788: /* Process buffered packets sent by the server. */
1.11 markus 789: client_process_buffered_input_packets();
790:
1.16 markus 791: if (compat20 && !channel_still_open()) {
792: debug("!channel_still_open.");
793: break;
794: }
795:
1.13 markus 796: /*
797: * Make packets of buffered stdin data, and buffer them for
798: * sending to the server.
799: */
1.17 markus 800: if (!compat20)
1.16 markus 801: client_make_packets_from_stdin_data();
1.11 markus 802:
1.13 markus 803: /*
804: * Make packets from buffered channel data, and buffer them
805: * for sending to the server.
806: */
1.11 markus 807: if (packet_not_very_much_data_to_write())
808: channel_output_poll();
809:
1.13 markus 810: /*
811: * Check if the window size has changed, and buffer a message
812: * about it to the server if so.
813: */
1.11 markus 814: client_check_window_change();
815:
816: if (quit_pending)
817: break;
818:
1.13 markus 819: /*
820: * Wait until we have something to do (something becomes
821: * available on one of the descriptors).
822: */
1.11 markus 823: client_wait_until_can_do_something(&readset, &writeset);
824:
825: if (quit_pending)
826: break;
827:
828: /* Do channel operations. */
829: channel_after_select(&readset, &writeset);
830:
1.17 markus 831: /* Buffer input from the connection. */
832: client_process_net_input(&readset);
833:
834: if (quit_pending)
835: break;
1.11 markus 836:
1.17 markus 837: if (!compat20) {
838: /* Buffer data from stdin */
839: client_process_input(&readset);
840: /*
841: * Process output to stdout and stderr. Output to
842: * the connection is processed elsewhere (above).
843: */
1.16 markus 844: client_process_output(&writeset);
1.17 markus 845: }
1.11 markus 846:
1.13 markus 847: /* Send as much buffered packet data as possible to the sender. */
1.11 markus 848: if (FD_ISSET(connection_out, &writeset))
849: packet_write_poll();
850: }
851:
852: /* Terminate the session. */
853:
854: /* Stop watching for window change. */
855: if (have_pty)
856: signal(SIGWINCH, SIG_DFL);
857:
858: /* Stop listening for connections. */
859: channel_stop_listening();
860:
1.13 markus 861: /*
862: * In interactive mode (with pseudo tty) display a message indicating
863: * that the connection has been closed.
864: */
1.11 markus 865: if (have_pty && options.log_level != SYSLOG_LEVEL_QUIET) {
866: snprintf(buf, sizeof buf, "Connection to %.64s closed.\r\n", host);
867: buffer_append(&stderr_buffer, buf, strlen(buf));
868: stderr_bytes += strlen(buf);
869: }
870: /* Output any buffered data for stdout. */
871: while (buffer_len(&stdout_buffer) > 0) {
872: len = write(fileno(stdout), buffer_ptr(&stdout_buffer),
1.14 deraadt 873: buffer_len(&stdout_buffer));
1.11 markus 874: if (len <= 0) {
875: error("Write failed flushing stdout buffer.");
876: break;
877: }
878: buffer_consume(&stdout_buffer, len);
879: }
880:
881: /* Output any buffered data for stderr. */
882: while (buffer_len(&stderr_buffer) > 0) {
883: len = write(fileno(stderr), buffer_ptr(&stderr_buffer),
1.14 deraadt 884: buffer_len(&stderr_buffer));
1.11 markus 885: if (len <= 0) {
886: error("Write failed flushing stderr buffer.");
887: break;
888: }
889: buffer_consume(&stderr_buffer, len);
890: }
891:
892: if (have_pty)
893: leave_raw_mode();
894:
895: /* Clear and free any buffers. */
896: memset(buf, 0, sizeof(buf));
897: buffer_free(&stdin_buffer);
898: buffer_free(&stdout_buffer);
899: buffer_free(&stderr_buffer);
900:
901: /* Report bytes transferred, and transfer rates. */
902: total_time = get_current_time() - start_time;
903: debug("Transferred: stdin %lu, stdout %lu, stderr %lu bytes in %.1f seconds",
904: stdin_bytes, stdout_bytes, stderr_bytes, total_time);
905: if (total_time > 0)
906: debug("Bytes per second: stdin %.1f, stdout %.1f, stderr %.1f",
907: stdin_bytes / total_time, stdout_bytes / total_time,
908: stderr_bytes / total_time);
909:
910: /* Return the exit status of the program. */
911: debug("Exit status %d", exit_status);
912: return exit_status;
1.15 markus 913: }
914:
915: /*********/
916:
917: void
918: client_input_stdout_data(int type, int plen)
919: {
920: unsigned int data_len;
921: char *data = packet_get_string(&data_len);
922: packet_integrity_check(plen, 4 + data_len, type);
923: buffer_append(&stdout_buffer, data, data_len);
924: stdout_bytes += data_len;
925: memset(data, 0, data_len);
926: xfree(data);
927: }
928: void
929: client_input_stderr_data(int type, int plen)
930: {
931: unsigned int data_len;
932: char *data = packet_get_string(&data_len);
933: packet_integrity_check(plen, 4 + data_len, type);
934: buffer_append(&stderr_buffer, data, data_len);
935: stdout_bytes += data_len;
936: memset(data, 0, data_len);
937: xfree(data);
938: }
939: void
940: client_input_exit_status(int type, int plen)
941: {
942: packet_integrity_check(plen, 4, type);
943: exit_status = packet_get_int();
944: /* Acknowledge the exit. */
945: packet_start(SSH_CMSG_EXIT_CONFIRMATION);
946: packet_send();
947: /*
948: * Must wait for packet to be sent since we are
949: * exiting the loop.
950: */
951: packet_write_wait();
952: /* Flag that we want to exit. */
953: quit_pending = 1;
954: }
955:
956: void
1.16 markus 957: client_init_dispatch_20()
958: {
959: dispatch_init(&dispatch_protocol_error);
960: dispatch_set(SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose);
961: dispatch_set(SSH2_MSG_CHANNEL_DATA, &channel_input_data);
962: dispatch_set(SSH2_MSG_CHANNEL_EOF, &channel_input_ieof);
963: dispatch_set(SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data);
964: dispatch_set(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation);
965: dispatch_set(SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
966: dispatch_set(SSH2_MSG_CHANNEL_REQUEST, &channel_input_channel_request);
967: dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust);
968: }
969: void
1.15 markus 970: client_init_dispatch_13()
971: {
972: dispatch_init(NULL);
973: dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_close);
974: dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_close_confirmation);
975: dispatch_set(SSH_MSG_CHANNEL_DATA, &channel_input_data);
976: dispatch_set(SSH_MSG_CHANNEL_DATA, &channel_input_data);
977: dispatch_set(SSH_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation);
978: dispatch_set(SSH_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
979: dispatch_set(SSH_MSG_PORT_OPEN, &channel_input_port_open);
980: dispatch_set(SSH_SMSG_AGENT_OPEN, &auth_input_open_request);
981: dispatch_set(SSH_SMSG_EXITSTATUS, &client_input_exit_status);
982: dispatch_set(SSH_SMSG_STDERR_DATA, &client_input_stderr_data);
983: dispatch_set(SSH_SMSG_STDOUT_DATA, &client_input_stdout_data);
984: dispatch_set(SSH_SMSG_X11_OPEN, &x11_input_open);
985: }
986: void
987: client_init_dispatch_15()
988: {
989: client_init_dispatch_13();
990: dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_ieof);
991: dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, & channel_input_oclose);
992: }
993: void
994: client_init_dispatch()
995: {
1.16 markus 996: if (compat20)
997: client_init_dispatch_20();
998: else if (compat13)
1.15 markus 999: client_init_dispatch_13();
1000: else
1001: client_init_dispatch_15();
1.16 markus 1002: }
1003:
1004: void
1005: client_input_channel_req(int id, void *arg)
1006: {
1007: Channel *c = NULL;
1008: unsigned int len;
1009: int success = 0;
1010: int reply;
1011: char *rtype;
1012:
1013: rtype = packet_get_string(&len);
1014: reply = packet_get_char();
1015:
1.18 ! markus 1016: debug("session_input_channel_req: rtype %s reply %d", rtype, reply);
1.16 markus 1017:
1018: c = channel_lookup(id);
1019: if (c == NULL)
1020: fatal("session_input_channel_req: channel %d: bad channel", id);
1021:
1022: if (session_ident == -1) {
1023: error("client_input_channel_req: no channel %d", id);
1024: } else if (id != session_ident) {
1025: error("client_input_channel_req: bad channel %d != %d",
1026: id, session_ident);
1027: } else if (strcmp(rtype, "exit-status") == 0) {
1028: success = 1;
1029: exit_status = packet_get_int();
1030: }
1031: if (reply) {
1032: packet_start(success ?
1033: SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE);
1034: packet_put_int(c->remote_id);
1035: packet_send();
1036: }
1037: xfree(rtype);
1038: }
1039:
1040: void
1041: client_set_session_ident(int id)
1042: {
1043: debug("client_set_session_ident: id %d", id);
1044: session_ident = id;
1045: channel_register_callback(id, SSH2_MSG_CHANNEL_REQUEST,
1046: client_input_channel_req, (void *)0);
1.1 deraadt 1047: }