summaryrefslogtreecommitdiff
path: root/clientloop.c
blob: 8f16d2fb9fa673fa0aaabdf499e948dbc5d2d967 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
/*
 * Author: Tatu Ylonen <ylo@cs.hut.fi>
 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
 *                    All rights reserved
 * The main loop for the interactive session (client side).
 *
 * As far as I am concerned, the code I have written for this software
 * can be used freely for any purpose.  Any derived versions of this
 * software must be clearly marked as such, and if the derived work is
 * incompatible with the protocol description in the RFC file, it must be
 * called by a name other than "ssh" or "Secure Shell".
 *
 *
 * Copyright (c) 1999 Theo de Raadt.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 *
 * SSH2 support added by Markus Friedl.
 * Copyright (c) 1999,2000 Markus Friedl.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "includes.h"
RCSID("$OpenBSD: clientloop.c,v 1.40 2000/11/06 23:04:56 markus Exp $");

#include "xmalloc.h"
#include "ssh.h"
#include "packet.h"
#include "buffer.h"
#include "readconf.h"

#include "ssh2.h"
#include "compat.h"
#include "channels.h"
#include "dispatch.h"

#include "buffer.h"
#include "bufaux.h"

#include <openssl/dsa.h>
#include <openssl/rsa.h>
#include "key.h"
#include "authfd.h"

/* import options */
extern Options options;

/* Flag indicating that stdin should be redirected from /dev/null. */
extern int stdin_null_flag;

/*
 * Name of the host we are connecting to.  This is the name given on the
 * command line, or the HostName specified for the user-supplied name in a
 * configuration file.
 */
extern char *host;

/*
 * Flag to indicate that we have received a window change signal which has
 * not yet been processed.  This will cause a message indicating the new
 * window size to be sent to the server a little later.  This is volatile
 * because this is updated in a signal handler.
 */
static volatile int received_window_change_signal = 0;

/* Terminal modes, as saved by enter_raw_mode. */
static struct termios saved_tio;

/*
 * Flag indicating whether we are in raw mode.  This is used by
 * enter_raw_mode and leave_raw_mode.
 */
static int in_raw_mode = 0;

/* Flag indicating whether the user\'s terminal is in non-blocking mode. */
static int in_non_blocking_mode = 0;

/* Common data for the client loop code. */
static int quit_pending;	/* Set to non-zero to quit the client loop. */
static int escape_char;		/* Escape character. */
static int escape_pending;	/* Last character was the escape character */
static int last_was_cr;		/* Last character was a newline. */
static int exit_status;		/* Used to store the exit status of the command. */
static int stdin_eof;		/* EOF has been encountered on standard error. */
static Buffer stdin_buffer;	/* Buffer for stdin data. */
static Buffer stdout_buffer;	/* Buffer for stdout data. */
static Buffer stderr_buffer;	/* Buffer for stderr data. */
static unsigned long stdin_bytes, stdout_bytes, stderr_bytes;
static unsigned int buffer_high;/* Soft max buffer size. */
static int max_fd;		/* Maximum file descriptor number in select(). */
static int connection_in;	/* Connection to server (input). */
static int connection_out;	/* Connection to server (output). */


void	client_init_dispatch(void);
int	session_ident = -1;

/* Returns the user\'s terminal to normal mode if it had been put in raw mode. */

void
leave_raw_mode()
{
	if (!in_raw_mode)
		return;
	in_raw_mode = 0;
	if (tcsetattr(fileno(stdin), TCSADRAIN, &saved_tio) < 0)
		perror("tcsetattr");

	fatal_remove_cleanup((void (*) (void *)) leave_raw_mode, NULL);
}

/* Puts the user\'s terminal in raw mode. */

void
enter_raw_mode()
{
	struct termios tio;

	if (tcgetattr(fileno(stdin), &tio) < 0)
		perror("tcgetattr");
	saved_tio = tio;
	tio.c_iflag |= IGNPAR;
	tio.c_iflag &= ~(ISTRIP | INLCR | IGNCR | ICRNL | IXON | IXANY | IXOFF);
	tio.c_lflag &= ~(ISIG | ICANON | ECHO | ECHOE | ECHOK | ECHONL);
#ifdef IEXTEN
	tio.c_lflag &= ~IEXTEN;
#endif				/* IEXTEN */
	tio.c_oflag &= ~OPOST;
	tio.c_cc[VMIN] = 1;
	tio.c_cc[VTIME] = 0;
	if (tcsetattr(fileno(stdin), TCSADRAIN, &tio) < 0)
		perror("tcsetattr");
	in_raw_mode = 1;

	fatal_add_cleanup((void (*) (void *)) leave_raw_mode, NULL);
}

/* Restores stdin to blocking mode. */

void
leave_non_blocking()
{
	if (in_non_blocking_mode) {
		(void) fcntl(fileno(stdin), F_SETFL, 0);
		in_non_blocking_mode = 0;
		fatal_remove_cleanup((void (*) (void *)) leave_non_blocking, NULL);
	}
}

/* Puts stdin terminal in non-blocking mode. */

void
enter_non_blocking()
{
	in_non_blocking_mode = 1;
	(void) fcntl(fileno(stdin), F_SETFL, O_NONBLOCK);
	fatal_add_cleanup((void (*) (void *)) leave_non_blocking, NULL);
}

/*
 * Signal handler for the window change signal (SIGWINCH).  This just sets a
 * flag indicating that the window has changed.
 */

void
window_change_handler(int sig)
{
	received_window_change_signal = 1;
	signal(SIGWINCH, window_change_handler);
}

/*
 * Signal handler for signals that cause the program to terminate.  These
 * signals must be trapped to restore terminal modes.
 */

void
signal_handler(int sig)
{
	if (in_raw_mode)
		leave_raw_mode();
	if (in_non_blocking_mode)
		leave_non_blocking();
	channel_stop_listening();
	packet_close();
	fatal("Killed by signal %d.", sig);
}

/*
 * Returns current time in seconds from Jan 1, 1970 with the maximum
 * available resolution.
 */

double
get_current_time()
{
	struct timeval tv;
	gettimeofday(&tv, NULL);
	return (double) tv.tv_sec + (double) tv.tv_usec / 1000000.0;
}

/*
 * This is called when the interactive is entered.  This checks if there is
 * an EOF coming on stdin.  We must check this explicitly, as select() does
 * not appear to wake up when redirecting from /dev/null.
 */

void
client_check_initial_eof_on_stdin()
{
	int len;
	char buf[1];

	/*
	 * If standard input is to be "redirected from /dev/null", we simply
	 * mark that we have seen an EOF and send an EOF message to the
	 * server. Otherwise, we try to read a single character; it appears
	 * that for some files, such /dev/null, select() never wakes up for
	 * read for this descriptor, which means that we never get EOF.  This
	 * way we will get the EOF if stdin comes from /dev/null or similar.
	 */
	if (stdin_null_flag) {
		/* Fake EOF on stdin. */
		debug("Sending eof.");
		stdin_eof = 1;
		packet_start(SSH_CMSG_EOF);
		packet_send();
	} else {
		enter_non_blocking();

		/* Check for immediate EOF on stdin. */
		len = read(fileno(stdin), buf, 1);
		if (len == 0) {
			/* EOF.  Record that we have seen it and send EOF to server. */
			debug("Sending eof.");
			stdin_eof = 1;
			packet_start(SSH_CMSG_EOF);
			packet_send();
		} else if (len > 0) {
			/*
			 * Got data.  We must store the data in the buffer,
			 * and also process it as an escape character if
			 * appropriate.
			 */
			if ((unsigned char) buf[0] == escape_char)
				escape_pending = 1;
			else {
				buffer_append(&stdin_buffer, buf, 1);
				stdin_bytes += 1;
			}
		}
		leave_non_blocking();
	}
}


/*
 * Make packets from buffered stdin data, and buffer them for sending to the
 * connection.
 */

void
client_make_packets_from_stdin_data()
{
	unsigned int len;

	/* Send buffered stdin data to the server. */
	while (buffer_len(&stdin_buffer) > 0 &&
	       packet_not_very_much_data_to_write()) {
		len = buffer_len(&stdin_buffer);
		/* Keep the packets at reasonable size. */
		if (len > packet_get_maxsize())
			len = packet_get_maxsize();
		packet_start(SSH_CMSG_STDIN_DATA);
		packet_put_string(buffer_ptr(&stdin_buffer), len);
		packet_send();
		buffer_consume(&stdin_buffer, len);
		/* If we have a pending EOF, send it now. */
		if (stdin_eof && buffer_len(&stdin_buffer) == 0) {
			packet_start(SSH_CMSG_EOF);
			packet_send();
		}
	}
}

/*
 * Checks if the client window has changed, and sends a packet about it to
 * the server if so.  The actual change is detected elsewhere (by a software
 * interrupt on Unix); this just checks the flag and sends a message if
 * appropriate.
 */

void
client_check_window_change()
{
	struct winsize ws;

	if (! received_window_change_signal)
		return;
	/** XXX race */
	received_window_change_signal = 0;

	if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0)
		return;

	debug2("client_check_window_change: changed");

	if (compat20) {
		channel_request_start(session_ident, "window-change", 0);
		packet_put_int(ws.ws_col);
		packet_put_int(ws.ws_row);
		packet_put_int(ws.ws_xpixel);
		packet_put_int(ws.ws_ypixel);
		packet_send();
	} else {
		packet_start(SSH_CMSG_WINDOW_SIZE);
		packet_put_int(ws.ws_row);
		packet_put_int(ws.ws_col);
		packet_put_int(ws.ws_xpixel);
		packet_put_int(ws.ws_ypixel);
		packet_send();
	}
}

/*
 * Waits until the client can do something (some data becomes available on
 * one of the file descriptors).
 */

void
client_wait_until_can_do_something(fd_set * readset, fd_set * writeset)
{
	/* Initialize select masks. */
	FD_ZERO(readset);
	FD_ZERO(writeset);

	if (!compat20) {
		/* Read from the connection, unless our buffers are full. */
		if (buffer_len(&stdout_buffer) < buffer_high &&
		    buffer_len(&stderr_buffer) < buffer_high &&
		    channel_not_very_much_buffered_data())
			FD_SET(connection_in, readset);
		/*
		 * Read from stdin, unless we have seen EOF or have very much
		 * buffered data to send to the server.
		 */
		if (!stdin_eof && packet_not_very_much_data_to_write())
			FD_SET(fileno(stdin), readset);

		/* Select stdout/stderr if have data in buffer. */
		if (buffer_len(&stdout_buffer) > 0)
			FD_SET(fileno(stdout), writeset);
		if (buffer_len(&stderr_buffer) > 0)
			FD_SET(fileno(stderr), writeset);
	} else {
		FD_SET(connection_in, readset);
	}

	/* Add any selections by the channel mechanism. */
	channel_prepare_select(readset, writeset);

	/* Select server connection if have data to write to the server. */
	if (packet_have_data_to_write())
		FD_SET(connection_out, writeset);

/* move UP XXX */
	/* Update maximum file descriptor number, if appropriate. */
	if (channel_max_fd() > max_fd)
		max_fd = channel_max_fd();

	/*
	 * Wait for something to happen.  This will suspend the process until
	 * some selected descriptor can be read, written, or has some other
	 * event pending. Note: if you want to implement SSH_MSG_IGNORE
	 * messages to fool traffic analysis, this might be the place to do
	 * it: just have a random timeout for the select, and send a random
	 * SSH_MSG_IGNORE packet when the timeout expires.
	 */

	if (select(max_fd + 1, readset, writeset, NULL, NULL) < 0) {
		char buf[100];
		/* Some systems fail to clear these automatically. */
		FD_ZERO(readset);
		FD_ZERO(writeset);
		if (errno == EINTR)
			return;
		/* Note: we might still have data in the buffers. */
		snprintf(buf, sizeof buf, "select: %s\r\n", strerror(errno));
		buffer_append(&stderr_buffer, buf, strlen(buf));
		stderr_bytes += strlen(buf);
		quit_pending = 1;
	}
}

void
client_suspend_self(Buffer *bin, Buffer *bout, Buffer *berr)
{
	struct winsize oldws, newws;

	/* Flush stdout and stderr buffers. */
	if (buffer_len(bout) > 0)
		atomicio(write, fileno(stdout), buffer_ptr(bout), buffer_len(bout));
	if (buffer_len(berr) > 0)
		atomicio(write, fileno(stderr), buffer_ptr(berr), buffer_len(berr));

	leave_raw_mode();

	/*
	 * Free (and clear) the buffer to reduce the amount of data that gets
	 * written to swap.
	 */
	buffer_free(bin);
	buffer_free(bout);
	buffer_free(berr);

	/* Save old window size. */
	ioctl(fileno(stdin), TIOCGWINSZ, &oldws);

	/* Send the suspend signal to the program itself. */
	kill(getpid(), SIGTSTP);

	/* Check if the window size has changed. */
	if (ioctl(fileno(stdin), TIOCGWINSZ, &newws) >= 0 &&
	    (oldws.ws_row != newws.ws_row ||
	     oldws.ws_col != newws.ws_col ||
	     oldws.ws_xpixel != newws.ws_xpixel ||
	     oldws.ws_ypixel != newws.ws_ypixel))
		received_window_change_signal = 1;

	/* OK, we have been continued by the user. Reinitialize buffers. */
	buffer_init(bin);
	buffer_init(bout);
	buffer_init(berr);

	enter_raw_mode();
}

void
client_process_net_input(fd_set * readset)
{
	int len;
	char buf[8192];

	/*
	 * Read input from the server, and add any such data to the buffer of
	 * the packet subsystem.
	 */
	if (FD_ISSET(connection_in, readset)) {
		/* Read as much as possible. */
		len = read(connection_in, buf, sizeof(buf));
		if (len == 0) {
			/* Received EOF.  The remote host has closed the connection. */
			snprintf(buf, sizeof buf, "Connection to %.300s closed by remote host.\r\n",
				 host);
			buffer_append(&stderr_buffer, buf, strlen(buf));
			stderr_bytes += strlen(buf);
			quit_pending = 1;
			return;
		}
		/*
		 * There is a kernel bug on Solaris that causes select to
		 * sometimes wake up even though there is no data available.
		 */
		if (len < 0 && errno == EAGAIN)
			len = 0;

		if (len < 0) {
			/* An error has encountered.  Perhaps there is a network problem. */
			snprintf(buf, sizeof buf, "Read from remote host %.300s: %.100s\r\n",
				 host, strerror(errno));
			buffer_append(&stderr_buffer, buf, strlen(buf));
			stderr_bytes += strlen(buf);
			quit_pending = 1;
			return;
		}
		packet_process_incoming(buf, len);
	}
}

/* process the characters one by one */
int
process_escapes(Buffer *bin, Buffer *bout, Buffer *berr, char *buf, int len)
{
	char string[1024];
	pid_t pid;
	int bytes = 0;
	unsigned int i;
	unsigned char ch;
	char *s;

	for (i = 0; i < len; i++) {
		/* Get one character at a time. */
		ch = buf[i];

		if (escape_pending) {
			/* We have previously seen an escape character. */
			/* Clear the flag now. */
			escape_pending = 0;

			/* Process the escaped character. */
			switch (ch) {
			case '.':
				/* Terminate the connection. */
				snprintf(string, sizeof string, "%c.\r\n", escape_char);
				buffer_append(berr, string, strlen(string));
				/*stderr_bytes += strlen(string); XXX*/

				quit_pending = 1;
				return -1;

			case 'Z' - 64:
				/* Suspend the program. */
				/* Print a message to that effect to the user. */
				snprintf(string, sizeof string, "%c^Z [suspend ssh]\r\n", escape_char);
				buffer_append(berr, string, strlen(string));
				/*stderr_bytes += strlen(string); XXX*/

				/* Restore terminal modes and suspend. */
				client_suspend_self(bin, bout, berr);

				/* We have been continued. */
				continue;

			case '&':
				/* XXX does not work yet with proto 2 */
				if (compat20)
					continue;
				/*
				 * Detach the program (continue to serve connections,
				 * but put in background and no more new connections).
				 */
				if (!stdin_eof) {
					/*
					 * Sending SSH_CMSG_EOF alone does not always appear
					 * to be enough.  So we try to send an EOF character
					 * first.
					 */
					packet_start(SSH_CMSG_STDIN_DATA);
					packet_put_string("\004", 1);
					packet_send();
					/* Close stdin. */
					stdin_eof = 1;
					if (buffer_len(bin) == 0) {
						packet_start(SSH_CMSG_EOF);
						packet_send();
					}
				}
				/* Restore tty modes. */
				leave_raw_mode();

				/* Stop listening for new connections. */
				channel_stop_listening();

				printf("%c& [backgrounded]\n", escape_char);

				/* Fork into background. */
				pid = fork();
				if (pid < 0) {
					error("fork: %.100s", strerror(errno));
					continue;
				}
				if (pid != 0) {	/* This is the parent. */
					/* The parent just exits. */
					exit(0);
				}
				/* The child continues serving connections. */
				continue; /*XXX ? */

			case '?':
				snprintf(string, sizeof string,
"%c?\r\n\
Supported escape sequences:\r\n\
~.  - terminate connection\r\n\
~^Z - suspend ssh\r\n\
~#  - list forwarded connections\r\n\
~&  - background ssh (when waiting for connections to terminate)\r\n\
~?  - this message\r\n\
~~  - send the escape character by typing it twice\r\n\
(Note that escapes are only recognized immediately after newline.)\r\n",
					 escape_char);
				buffer_append(berr, string, strlen(string));
				continue;

			case '#':
				snprintf(string, sizeof string, "%c#\r\n", escape_char);
				buffer_append(berr, string, strlen(string));
				s = channel_open_message();
				buffer_append(berr, s, strlen(s));
				xfree(s);
				continue;

			default:
				if (ch != escape_char) {
					buffer_put_char(bin, escape_char);
					bytes++;
				}
				/* Escaped characters fall through here */
				break;
			}
		} else {
			/*
			 * The previous character was not an escape char. Check if this
			 * is an escape.
			 */
			if (last_was_cr && ch == escape_char) {
				/* It is. Set the flag and continue to next character. */
				escape_pending = 1;
				continue;
			}
		}

		/*
		 * Normal character.  Record whether it was a newline,
		 * and append it to the buffer.
		 */
		last_was_cr = (ch == '\r' || ch == '\n');
		buffer_put_char(bin, ch);
		bytes++;
	}
	return bytes;
}

void
client_process_input(fd_set * readset)
{
	int ret;
	int len;
	char buf[8192];

	/* Read input from stdin. */
	if (FD_ISSET(fileno(stdin), readset)) {
		/* Read as much as possible. */
		len = read(fileno(stdin), buf, sizeof(buf));
		if (len <= 0) {
			/*
			 * Received EOF or error.  They are treated
			 * similarly, except that an error message is printed
			 * if it was an error condition.
			 */
			if (len < 0) {
				snprintf(buf, sizeof buf, "read: %.100s\r\n", strerror(errno));
				buffer_append(&stderr_buffer, buf, strlen(buf));
				stderr_bytes += strlen(buf);
			}
			/* Mark that we have seen EOF. */
			stdin_eof = 1;
			/*
			 * Send an EOF message to the server unless there is
			 * data in the buffer.  If there is data in the
			 * buffer, no message will be sent now.  Code
			 * elsewhere will send the EOF when the buffer
			 * becomes empty if stdin_eof is set.
			 */
			if (buffer_len(&stdin_buffer) == 0) {
				packet_start(SSH_CMSG_EOF);
				packet_send();
			}
		} else if (escape_char == -1) {
			/*
			 * Normal successful read, and no escape character.
			 * Just append the data to buffer.
			 */
			buffer_append(&stdin_buffer, buf, len);
			stdin_bytes += len;
		} else {
			/*
			 * Normal, successful read.  But we have an escape character
			 * and have to process the characters one by one.
			 */
			ret = process_escapes(&stdin_buffer, &stdout_buffer, &stderr_buffer, buf, len);
			if (ret == -1)
				return;
			stdout_bytes += ret;
		}
	}
}

void
client_process_output(fd_set * writeset)
{
	int len;
	char buf[100];

	/* Write buffered output to stdout. */
	if (FD_ISSET(fileno(stdout), writeset)) {
		/* Write as much data as possible. */
		len = write(fileno(stdout), buffer_ptr(&stdout_buffer),
		    buffer_len(&stdout_buffer));
		if (len <= 0) {
			if (errno == EAGAIN)
				len = 0;
			else {
				/*
				 * An error or EOF was encountered.  Put an
				 * error message to stderr buffer.
				 */
				snprintf(buf, sizeof buf, "write stdout: %.50s\r\n", strerror(errno));
				buffer_append(&stderr_buffer, buf, strlen(buf));
				stderr_bytes += strlen(buf);
				quit_pending = 1;
				return;
			}
		}
		/* Consume printed data from the buffer. */
		buffer_consume(&stdout_buffer, len);
	}
	/* Write buffered output to stderr. */
	if (FD_ISSET(fileno(stderr), writeset)) {
		/* Write as much data as possible. */
		len = write(fileno(stderr), buffer_ptr(&stderr_buffer),
		    buffer_len(&stderr_buffer));
		if (len <= 0) {
			if (errno == EAGAIN)
				len = 0;
			else {
				/* EOF or error, but can't even print error message. */
				quit_pending = 1;
				return;
			}
		}
		/* Consume printed characters from the buffer. */
		buffer_consume(&stderr_buffer, len);
	}
}

/*
 * Get packets from the connection input buffer, and process them as long as
 * there are packets available.
 *
 * Any unknown packets received during the actual
 * session cause the session to terminate.  This is
 * intended to make debugging easier since no
 * confirmations are sent.  Any compatible protocol
 * extensions must be negotiated during the
 * preparatory phase.
 */

void
client_process_buffered_input_packets()
{
	dispatch_run(DISPATCH_NONBLOCK, &quit_pending, NULL);
}

/* scan buf[] for '~' before sending data to the peer */

int
simple_escape_filter(Channel *c, char *buf, int len)
{
	/* XXX we assume c->extended is writeable */
	return process_escapes(&c->input, &c->output, &c->extended, buf, len);
}

/*
 * Implements the interactive session with the server.  This is called after
 * the user has been authenticated, and a command has been started on the
 * remote host.  If escape_char != -1, it is the character used as an escape
 * character for terminating or suspending the session.
 */

int
client_loop(int have_pty, int escape_char_arg, int ssh2_chan_id)
{
	double start_time, total_time;
	int len;
	char buf[100];

	debug("Entering interactive session.");

	start_time = get_current_time();

	/* Initialize variables. */
	escape_pending = 0;
	last_was_cr = 1;
	exit_status = -1;
	stdin_eof = 0;
	buffer_high = 64 * 1024;
	connection_in = packet_get_connection_in();
	connection_out = packet_get_connection_out();
	max_fd = connection_in;
	if (connection_out > max_fd)
		max_fd = connection_out;
	stdin_bytes = 0;
	stdout_bytes = 0;
	stderr_bytes = 0;
	quit_pending = 0;
	escape_char = escape_char_arg;

	/* Initialize buffers. */
	buffer_init(&stdin_buffer);
	buffer_init(&stdout_buffer);
	buffer_init(&stderr_buffer);

	client_init_dispatch();

	/* Set signal handlers to restore non-blocking mode.  */
	signal(SIGINT, signal_handler);
	signal(SIGQUIT, signal_handler);
	signal(SIGTERM, signal_handler);
	signal(SIGPIPE, SIG_IGN);
	if (have_pty)
		signal(SIGWINCH, window_change_handler);

	if (have_pty)
		enter_raw_mode();

	/* Check if we should immediately send eof on stdin. */
	if (!compat20)
		client_check_initial_eof_on_stdin();

	if (compat20 && escape_char != -1)
		channel_register_filter(ssh2_chan_id, simple_escape_filter);

	/* Main loop of the client for the interactive session mode. */
	while (!quit_pending) {
		fd_set readset, writeset;

		/* Process buffered packets sent by the server. */
		client_process_buffered_input_packets();

		if (compat20 && !channel_still_open()) {
			debug2("!channel_still_open.");
			break;
		}

		/*
		 * Make packets of buffered stdin data, and buffer them for
		 * sending to the server.
		 */
		if (!compat20)
			client_make_packets_from_stdin_data();

		/*
		 * Make packets from buffered channel data, and buffer them
		 * for sending to the server.
		 */
		if (packet_not_very_much_data_to_write())
			channel_output_poll();

		/*
		 * Check if the window size has changed, and buffer a message
		 * about it to the server if so.
		 */
		client_check_window_change();

		if (quit_pending)
			break;

		/*
		 * Wait until we have something to do (something becomes
		 * available on one of the descriptors).
		 */
		client_wait_until_can_do_something(&readset, &writeset);

		if (quit_pending)
			break;

		/* Do channel operations. */
		channel_after_select(&readset, &writeset);

		/* Buffer input from the connection.  */
		client_process_net_input(&readset);

		if (quit_pending)
			break;

		if (!compat20) {
			/* Buffer data from stdin */
			client_process_input(&readset);
			/*
			 * Process output to stdout and stderr.  Output to
			 * the connection is processed elsewhere (above).
			 */
			client_process_output(&writeset);
		}

		/* Send as much buffered packet data as possible to the sender. */
		if (FD_ISSET(connection_out, &writeset))
			packet_write_poll();
	}

	/* Terminate the session. */

	/* Stop watching for window change. */
	if (have_pty)
		signal(SIGWINCH, SIG_DFL);

	/* Stop listening for connections. */
	channel_stop_listening();

	/*
	 * In interactive mode (with pseudo tty) display a message indicating
	 * that the connection has been closed.
	 */
	if (have_pty && options.log_level != SYSLOG_LEVEL_QUIET) {
		snprintf(buf, sizeof buf, "Connection to %.64s closed.\r\n", host);
		buffer_append(&stderr_buffer, buf, strlen(buf));
		stderr_bytes += strlen(buf);
	}
	/* Output any buffered data for stdout. */
	while (buffer_len(&stdout_buffer) > 0) {
		len = write(fileno(stdout), buffer_ptr(&stdout_buffer),
		    buffer_len(&stdout_buffer));
		if (len <= 0) {
			error("Write failed flushing stdout buffer.");
			break;
		}
		buffer_consume(&stdout_buffer, len);
	}

	/* Output any buffered data for stderr. */
	while (buffer_len(&stderr_buffer) > 0) {
		len = write(fileno(stderr), buffer_ptr(&stderr_buffer),
		    buffer_len(&stderr_buffer));
		if (len <= 0) {
			error("Write failed flushing stderr buffer.");
			break;
		}
		buffer_consume(&stderr_buffer, len);
	}

	if (have_pty)
		leave_raw_mode();

	/* Clear and free any buffers. */
	memset(buf, 0, sizeof(buf));
	buffer_free(&stdin_buffer);
	buffer_free(&stdout_buffer);
	buffer_free(&stderr_buffer);

	/* Report bytes transferred, and transfer rates. */
	total_time = get_current_time() - start_time;
	debug("Transferred: stdin %lu, stdout %lu, stderr %lu bytes in %.1f seconds",
	      stdin_bytes, stdout_bytes, stderr_bytes, total_time);
	if (total_time > 0)
		debug("Bytes per second: stdin %.1f, stdout %.1f, stderr %.1f",
		      stdin_bytes / total_time, stdout_bytes / total_time,
		      stderr_bytes / total_time);

	/* Return the exit status of the program. */
	debug("Exit status %d", exit_status);
	return exit_status;
}

/*********/

void
client_input_stdout_data(int type, int plen, void *ctxt)
{
	unsigned int data_len;
	char *data = packet_get_string(&data_len);
	packet_integrity_check(plen, 4 + data_len, type);
	buffer_append(&stdout_buffer, data, data_len);
	stdout_bytes += data_len;
	memset(data, 0, data_len);
	xfree(data);
}
void
client_input_stderr_data(int type, int plen, void *ctxt)
{
	unsigned int data_len;
	char *data = packet_get_string(&data_len);
	packet_integrity_check(plen, 4 + data_len, type);
	buffer_append(&stderr_buffer, data, data_len);
	stdout_bytes += data_len;
	memset(data, 0, data_len);
	xfree(data);
}
void
client_input_exit_status(int type, int plen, void *ctxt)
{
	packet_integrity_check(plen, 4, type);
	exit_status = packet_get_int();
	/* Acknowledge the exit. */
	packet_start(SSH_CMSG_EXIT_CONFIRMATION);
	packet_send();
	/*
	 * Must wait for packet to be sent since we are
	 * exiting the loop.
	 */
	packet_write_wait();
	/* Flag that we want to exit. */
	quit_pending = 1;
}

Channel *
client_request_forwarded_tcpip(const char *request_type, int rchan)
{
	Channel* c = NULL;
	char *listen_address, *originator_address;
	int listen_port, originator_port;
	int sock, newch;

	/* Get rest of the packet */
	listen_address = packet_get_string(NULL);
	listen_port = packet_get_int();
	originator_address = packet_get_string(NULL);
	originator_port = packet_get_int();
	packet_done();

	debug("client_request_forwarded_tcpip: listen %s port %d, originator %s port %d",
	    listen_address, listen_port, originator_address, originator_port);

	sock = channel_connect_by_listen_adress(listen_port);
	if (sock >= 0) {
		newch = channel_new("forwarded-tcpip",
		    SSH_CHANNEL_OPEN, sock, sock, -1,
		    CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_WINDOW_DEFAULT, 0,
		    xstrdup(originator_address), 1);
		c = channel_lookup(newch);
	}
	xfree(originator_address);
	xfree(listen_address);
	return c;
}

Channel*
client_request_x11(const char *request_type, int rchan)
{
	Channel *c = NULL;
	char *originator;
	int originator_port;
	int sock, newch;

	if (!options.forward_x11) {
		error("Warning: ssh server tried X11 forwarding.");
		error("Warning: this is probably a break in attempt by a malicious server.");
		return NULL;
	}
	originator = packet_get_string(NULL);
	if (datafellows & SSH_BUG_X11FWD) {
		debug2("buggy server: x11 request w/o originator_port");
		originator_port = 0;
	} else {
		originator_port = packet_get_int();
	}
	packet_done();
	/* XXX check permission */
	sock = x11_connect_display();
	if (sock >= 0) {
		newch = channel_new("x11",
		    SSH_CHANNEL_X11_OPEN, sock, sock, -1,
		    CHAN_TCP_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 0,
		    xstrdup("x11"), 1);
		c = channel_lookup(newch);
	}
	xfree(originator);
	return c;
}

Channel*
client_request_agent(const char *request_type, int rchan)
{
	Channel *c = NULL;
	int sock, newch;

	if (!options.forward_agent) {
		error("Warning: ssh server tried agent forwarding.");
		error("Warning: this is probably a break in attempt by a malicious server.");
		return NULL;
	}
	sock =  ssh_get_authentication_socket();
	if (sock >= 0) {
		newch = channel_new("authentication agent connection",
		    SSH_CHANNEL_OPEN, sock, sock, -1,
		    CHAN_X11_WINDOW_DEFAULT, CHAN_TCP_WINDOW_DEFAULT, 0,
		    xstrdup("authentication agent connection"), 1);
		c = channel_lookup(newch);
	}
	return c;
}

/* XXXX move to generic input handler */
void
client_input_channel_open(int type, int plen, void *ctxt)
{
	Channel *c = NULL;
	char *ctype;
	unsigned int len;
	int rchan;
	int rmaxpack;
	int rwindow;

	ctype = packet_get_string(&len);
	rchan = packet_get_int();
	rwindow = packet_get_int();
	rmaxpack = packet_get_int();

	debug("client_input_channel_open: ctype %s rchan %d win %d max %d",
	    ctype, rchan, rwindow, rmaxpack);

	if (strcmp(ctype, "forwarded-tcpip") == 0) {
		c = client_request_forwarded_tcpip(ctype, rchan);
	} else if (strcmp(ctype, "x11") == 0) {
		c = client_request_x11(ctype, rchan);
	} else if (strcmp(ctype, "auth-agent@openssh.com") == 0) {
		c = client_request_agent(ctype, rchan);
	}
/* XXX duplicate : */
	if (c != NULL) {
		debug("confirm %s", ctype);
		c->remote_id = rchan;
		c->remote_window = rwindow;
		c->remote_maxpacket = rmaxpack;

		packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
		packet_put_int(c->remote_id);
		packet_put_int(c->self);
		packet_put_int(c->local_window);
		packet_put_int(c->local_maxpacket);
		packet_send();
	} else {
		debug("failure %s", ctype);
		packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
		packet_put_int(rchan);
		packet_put_int(SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED);
		packet_put_cstring("bla bla");
		packet_put_cstring("");
		packet_send();
	}
	xfree(ctype);
}

void
client_init_dispatch_20()
{
	dispatch_init(&dispatch_protocol_error);
	dispatch_set(SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose);
	dispatch_set(SSH2_MSG_CHANNEL_DATA, &channel_input_data);
	dispatch_set(SSH2_MSG_CHANNEL_EOF, &channel_input_ieof);
	dispatch_set(SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data);
	dispatch_set(SSH2_MSG_CHANNEL_OPEN, &client_input_channel_open);
	dispatch_set(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation);
	dispatch_set(SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
	dispatch_set(SSH2_MSG_CHANNEL_REQUEST, &channel_input_channel_request);
	dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust);
}
void
client_init_dispatch_13()
{
	dispatch_init(NULL);
	dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_close);
	dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_close_confirmation);
	dispatch_set(SSH_MSG_CHANNEL_DATA, &channel_input_data);
	dispatch_set(SSH_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation);
	dispatch_set(SSH_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
	dispatch_set(SSH_MSG_PORT_OPEN, &channel_input_port_open);
	dispatch_set(SSH_SMSG_EXITSTATUS, &client_input_exit_status);
	dispatch_set(SSH_SMSG_STDERR_DATA, &client_input_stderr_data);
	dispatch_set(SSH_SMSG_STDOUT_DATA, &client_input_stdout_data);

	dispatch_set(SSH_SMSG_AGENT_OPEN, options.forward_agent ?
	    &auth_input_open_request : &deny_input_open);
	dispatch_set(SSH_SMSG_X11_OPEN, options.forward_x11 ?
	    &x11_input_open : &deny_input_open);
}
void
client_init_dispatch_15()
{
	client_init_dispatch_13();
	dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_ieof);
	dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, & channel_input_oclose);
}
void
client_init_dispatch()
{
	if (compat20)
		client_init_dispatch_20();
	else if (compat13)
		client_init_dispatch_13();
	else
		client_init_dispatch_15();
}

void
client_input_channel_req(int id, void *arg)
{
	Channel *c = NULL;
	unsigned int len;
	int success = 0;
	int reply;
	char *rtype;

	rtype = packet_get_string(&len);
	reply = packet_get_char();

	debug("client_input_channel_req: rtype %s reply %d", rtype, reply);

	c = channel_lookup(id);
	if (c == NULL)
		fatal("client_input_channel_req: channel %d: bad channel", id);

	if (session_ident == -1) {
		error("client_input_channel_req: no channel %d", id);
	} else if (id != session_ident) {
		error("client_input_channel_req: bad channel %d != %d",
		    id, session_ident);
	} else if (strcmp(rtype, "exit-status") == 0) {
		success = 1;
		exit_status = packet_get_int();
		packet_done();
	}
	if (reply) {
		packet_start(success ?
		    SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE);
		packet_put_int(c->remote_id);
		packet_send();
	}
	xfree(rtype);
}

void
client_set_session_ident(int id)
{
	debug2("client_set_session_ident: id %d", id);
	session_ident = id;
	channel_register_callback(id, SSH2_MSG_CHANNEL_REQUEST,
	    client_input_channel_req, (void *)0);
}