summaryrefslogtreecommitdiffstats
path: root/usr.bin/rlogin/rlogin.c
blob: c279535b649744e9dedf1a78ef2563cd980271d1 (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
/*
 * Copyright (c) 1983, 1990, 1993
 *	The Regents of the University of California.  All rights reserved.
 * Copyright (c) 2002 Networks Associates Technology, Inc.
 * All rights reserved.
 *
 * Portions of this software were developed for the FreeBSD Project by
 * ThinkSec AS and NAI Labs, the Security Research Division of Network
 * Associates, Inc.  under DARPA/SPAWAR contract N66001-01-C-8035
 * ("CBOSS"), as part of the DARPA CHATS research program.
 *
 * 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.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 REGENTS OR CONTRIBUTORS 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.
 */

#ifndef lint
static const char copyright[] =
"@(#) Copyright (c) 1983, 1990, 1993\n\
	The Regents of the University of California.  All rights reserved.\n";
#endif /* not lint */

#if 0
#ifndef lint
static const char sccsid[] = "@(#)rlogin.c	8.1 (Berkeley) 6/6/93";
#endif /* not lint */
#endif

#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");

/*
 * rlogin - remote login
 */

#include <sys/param.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <sys/wait.h>

#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/tcp.h>

#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <libutil.h>
#include <netdb.h>
#include <paths.h>
#include <pwd.h>
#include <setjmp.h>
#include <termios.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#ifndef TIOCPKT_WINDOW
#define	TIOCPKT_WINDOW	0x80
#endif

/* concession to Sun */
#ifndef SIGUSR1
#define	SIGUSR1	30
#endif

int eight, rem;
struct termios deftty;

int family = PF_UNSPEC;

int noescape;
u_char escapechar = '~';

#define	get_window_size(fd, wp)	ioctl(fd, TIOCGWINSZ, wp)
struct	winsize winsize;

void		catch_child(int);
void		copytochild(int);
void		doit(long) __dead2;
void		done(int) __dead2;
void		echo(char);
u_int		getescape(const char *);
void		lostpeer(int);
void		mode(int);
void		msg(const char *);
void		oob(int);
int		reader(int);
void		sendwindow(void);
void		setsignal(int);
void		sigwinch(int);
void		stop(char);
void		usage(void) __dead2;
void		writer(void);
void		writeroob(int);

int
main(int argc, char *argv[])
{
	struct passwd *pw;
	struct servent *sp;
	struct termios tty;
	long omask;
	int argoff, ch, dflag, Dflag, one;
	uid_t uid;
	char *host, *localname, *p, *user, term[1024];
	speed_t ospeed;
	struct sockaddr_storage ss;
	socklen_t sslen;
	size_t len, len2;
	int i;

	argoff = dflag = Dflag = 0;
	one = 1;
	host = localname = user = NULL;

	if ((p = rindex(argv[0], '/')))
		++p;
	else
		p = argv[0];

	if (strcmp(p, "rlogin"))
		host = p;

	/* handle "rlogin host flags" */
	if (!host && argc > 2 && argv[1][0] != '-') {
		host = argv[1];
		argoff = 1;
	}

#define	OPTIONS	"468DEde:i:l:"
	while ((ch = getopt(argc - argoff, argv + argoff, OPTIONS)) != -1)
		switch(ch) {
		case '4':
			family = PF_INET;
			break;

		case '6':
			family = PF_INET6;
			break;

		case '8':
			eight = 1;
			break;
		case 'D':
			Dflag = 1;
			break;
		case 'E':
			noescape = 1;
			break;
		case 'd':
			dflag = 1;
			break;
		case 'e':
			noescape = 0;
			escapechar = getescape(optarg);
			break;
		case 'i':
			if (getuid() != 0)
				errx(1, "-i user: permission denied");
			localname = optarg;
			break;
		case 'l':
			user = optarg;
			break;
		case '?':
		default:
			usage();
		}
	optind += argoff;

	/* if haven't gotten a host yet, do so */
	if (!host && !(host = argv[optind++]))
		usage();

	if (argv[optind])
		usage();

	if (!(pw = getpwuid(uid = getuid())))
		errx(1, "unknown user id");
	if (!user)
		user = pw->pw_name;
	if (!localname)
		localname = pw->pw_name;

	sp = NULL;
	sp = getservbyname("login", "tcp");
	if (sp == NULL)
		errx(1, "login/tcp: unknown service");

	if ((p = getenv("TERM")) != NULL)
		(void)strlcpy(term, p, sizeof(term));
	len = strlen(term);
	if (len < (sizeof(term) - 1) && tcgetattr(0, &tty) == 0) {
		/* start at 2 to include the / */
		for (ospeed = i = cfgetospeed(&tty), len2 = 2; i > 9; len2++)
			i /= 10;
		if (len + len2 < sizeof(term))
			(void)snprintf(term + len, len2 + 1, "/%d", ospeed);
	}

	(void)get_window_size(0, &winsize);

	(void)signal(SIGPIPE, lostpeer);
	/* will use SIGUSR1 for window size hack, so hold it off */
	omask = sigblock(sigmask(SIGURG) | sigmask(SIGUSR1));
	/*
	 * We set SIGURG and SIGUSR1 below so that an
	 * incoming signal will be held pending rather than being
	 * discarded. Note that these routines will be ready to get
	 * a signal by the time that they are unblocked below.
	 */
	(void)signal(SIGURG, copytochild);
	(void)signal(SIGUSR1, writeroob);

	rem = rcmd_af(&host, sp->s_port, localname, user, term, 0, family);

	if (rem < 0)
		exit(1);

	if (dflag &&
	    setsockopt(rem, SOL_SOCKET, SO_DEBUG, &one, sizeof(one)) < 0)
		warn("setsockopt");
	if (Dflag &&
	    setsockopt(rem, IPPROTO_TCP, TCP_NODELAY, &one, sizeof(one)) < 0)
		warn("setsockopt NODELAY (ignored)");

	sslen = sizeof(ss);
	one = IPTOS_LOWDELAY;
	if (getsockname(rem, (struct sockaddr *)&ss, &sslen) == 0 &&
	    ss.ss_family == AF_INET) {
		if (setsockopt(rem, IPPROTO_IP, IP_TOS, (char *)&one,
			       sizeof(int)) < 0)
			warn("setsockopt TOS (ignored)");
	} else
		if (ss.ss_family == AF_INET)
			warn("setsockopt getsockname failed");

	(void)setuid(uid);
	doit(omask);
	/*NOTREACHED*/
}

int child;

void
doit(long omask)
{

	(void)signal(SIGINT, SIG_IGN);
	setsignal(SIGHUP);
	setsignal(SIGQUIT);
	mode(1);
	child = fork();
	if (child == -1) {
		warn("fork");
		done(1);
	}
	if (child == 0) {
		if (reader(omask) == 0) {
			msg("connection closed");
			exit(0);
		}
		sleep(1);
		msg("\007connection closed");
		exit(1);
	}

	/*
	 * We may still own the socket, and may have a pending SIGURG (or might
	 * receive one soon) that we really want to send to the reader.  When
	 * one of these comes in, the trap copytochild simply copies such
	 * signals to the child. We can now unblock SIGURG and SIGUSR1
	 * that were set above.
	 */
	(void)sigsetmask(omask);
	(void)signal(SIGCHLD, catch_child);
	writer();
	msg("closed connection");
	done(0);
}

/* trap a signal, unless it is being ignored. */
void
setsignal(int sig)
{
	int omask = sigblock(sigmask(sig));

	if (signal(sig, exit) == SIG_IGN)
		(void)signal(sig, SIG_IGN);
	(void)sigsetmask(omask);
}

void
done(int status)
{
	int w, wstatus;

	mode(0);
	if (child > 0) {
		/* make sure catch_child does not snap it up */
		(void)signal(SIGCHLD, SIG_DFL);
		if (kill(child, SIGKILL) >= 0)
			while ((w = wait(&wstatus)) > 0 && w != child);
	}
	exit(status);
}

int dosigwinch;

/*
 * This is called when the reader process gets the out-of-band (urgent)
 * request to turn on the window-changing protocol.
 */
/* ARGSUSED */
void
writeroob(int signo __unused)
{
	if (dosigwinch == 0) {
		sendwindow();
		(void)signal(SIGWINCH, sigwinch);
	}
	dosigwinch = 1;
}

/* ARGSUSED */
void
catch_child(int signo __unused)
{
	pid_t pid;
	int status;

	for (;;) {
		pid = wait3(&status, WNOHANG|WUNTRACED, NULL);
		if (pid == 0)
			return;
		/* if the child (reader) dies, just quit */
		if (pid < 0 || (pid == child && !WIFSTOPPED(status)))
			done(WTERMSIG(status) | WEXITSTATUS(status));
	}
	/* NOTREACHED */
}

/*
 * writer: write to remote: 0 -> line.
 * ~.				terminate
 * ~^Z				suspend rlogin process.
 * ~<delayed-suspend char>	suspend rlogin process, but leave reader alone.
 */
void
writer(void)
{
	int bol, local, n;
	char c;

	bol = 1;			/* beginning of line */
	local = 0;
	for (;;) {
		n = read(STDIN_FILENO, &c, 1);
		if (n <= 0) {
			if (n < 0 && errno == EINTR)
				continue;
			break;
		}
		/*
		 * If we're at the beginning of the line and recognize a
		 * command character, then we echo locally.  Otherwise,
		 * characters are echo'd remotely.  If the command character
		 * is doubled, this acts as a force and local echo is
		 * suppressed.
		 */
		if (bol) {
			bol = 0;
			if (!noescape && c == escapechar) {
				local = 1;
				continue;
			}
		} else if (local) {
			local = 0;
			if (c == '.' || CCEQ(deftty.c_cc[VEOF], c)) {
				echo(c);
				break;
			}
			if (CCEQ(deftty.c_cc[VSUSP], c) ||
			    CCEQ(deftty.c_cc[VDSUSP], c)) {
				bol = 1;
				echo(c);
				stop(c);
				continue;
			}
			if (c != escapechar)
				(void)write(rem, &escapechar, 1);
		}

		if (write(rem, &c, 1) == 0) {
			msg("line gone");
			break;
		}
		bol = CCEQ(deftty.c_cc[VKILL], c) ||
		    CCEQ(deftty.c_cc[VEOF], c) ||
		    CCEQ(deftty.c_cc[VINTR], c) ||
		    CCEQ(deftty.c_cc[VSUSP], c) ||
		    c == '\r' || c == '\n';
	}
}

void
echo(char c)
{
	char *p;
	char buf[8];

	p = buf;
	c &= 0177;
	*p++ = escapechar;
	if (c < ' ') {
		*p++ = '^';
		*p++ = c + '@';
	} else if (c == 0177) {
		*p++ = '^';
		*p++ = '?';
	} else
		*p++ = c;
	*p++ = '\r';
	*p++ = '\n';
	(void)write(STDOUT_FILENO, buf, p - buf);
}

void
stop(char cmdc)
{
	mode(0);
	(void)signal(SIGCHLD, SIG_IGN);
	(void)kill(CCEQ(deftty.c_cc[VSUSP], cmdc) ? 0 : getpid(), SIGTSTP);
	(void)signal(SIGCHLD, catch_child);
	mode(1);
	sigwinch(0);			/* check for size changes */
}

/* ARGSUSED */
void
sigwinch(int signo __unused)
{
	struct winsize ws;

	if (dosigwinch && get_window_size(0, &ws) == 0 &&
	    bcmp(&ws, &winsize, sizeof(ws))) {
		winsize = ws;
		sendwindow();
	}
}

/*
 * Send the window size to the server via the magic escape
 */
void
sendwindow(void)
{
	struct winsize *wp;
	char obuf[4 + sizeof (struct winsize)];

	wp = (struct winsize *)(obuf+4);
	obuf[0] = 0377;
	obuf[1] = 0377;
	obuf[2] = 's';
	obuf[3] = 's';
	wp->ws_row = htons(winsize.ws_row);
	wp->ws_col = htons(winsize.ws_col);
	wp->ws_xpixel = htons(winsize.ws_xpixel);
	wp->ws_ypixel = htons(winsize.ws_ypixel);

	(void)write(rem, obuf, sizeof(obuf));
}

/*
 * reader: read from remote: line -> 1
 */
#define	READING	1
#define	WRITING	2

jmp_buf rcvtop;
int rcvcnt, rcvstate;
pid_t ppid;
char rcvbuf[8 * 1024];

/* ARGSUSED */
void
oob(int signo __unused)
{
	struct termios tty;
	int atmark, n, rcvd;
	char waste[BUFSIZ], mark;

	rcvd = 0;
	while (recv(rem, &mark, 1, MSG_OOB) < 0) {
		switch (errno) {
		case EWOULDBLOCK:
			/*
			 * Urgent data not here yet.  It may not be possible
			 * to send it yet if we are blocked for output and
			 * our input buffer is full.
			 */
			if (rcvcnt < (int)sizeof(rcvbuf)) {
				n = read(rem, rcvbuf + rcvcnt,
				    sizeof(rcvbuf) - rcvcnt);
				if (n <= 0)
					return;
				rcvd += n;
			} else {
				n = read(rem, waste, sizeof(waste));
				if (n <= 0)
					return;
			}
			continue;
		default:
			return;
		}
	}
	if (mark & TIOCPKT_WINDOW) {
		/* Let server know about window size changes */
		(void)kill(ppid, SIGUSR1);
	}
	if (!eight && (mark & TIOCPKT_NOSTOP)) {
		(void)tcgetattr(0, &tty);
		tty.c_iflag &= ~IXON;
		(void)tcsetattr(0, TCSANOW, &tty);
	}
	if (!eight && (mark & TIOCPKT_DOSTOP)) {
		(void)tcgetattr(0, &tty);
		tty.c_iflag |= (deftty.c_iflag & IXON);
		(void)tcsetattr(0, TCSANOW, &tty);
	}
	if (mark & TIOCPKT_FLUSHWRITE) {
		(void)tcflush(1, TCIOFLUSH);
		for (;;) {
			if (ioctl(rem, SIOCATMARK, &atmark) < 0) {
				warn("ioctl");
				break;
			}
			if (atmark)
				break;
			n = read(rem, waste, sizeof (waste));
			if (n <= 0)
				break;
		}
		/*
		 * Don't want any pending data to be output, so clear the recv
		 * buffer.  If we were hanging on a write when interrupted,
		 * don't want it to restart.  If we were reading, restart
		 * anyway.
		 */
		rcvcnt = 0;
		longjmp(rcvtop, 1);
	}

	/* oob does not do FLUSHREAD (alas!) */

	/*
	 * If we filled the receive buffer while a read was pending, longjmp
	 * to the top to restart appropriately.  Don't abort a pending write,
	 * however, or we won't know how much was written.
	 */
	if (rcvd && rcvstate == READING)
		longjmp(rcvtop, 1);
}

/* reader: read from remote: line -> 1 */
int
reader(int omask)
{
	int n, remaining;
	char *bufp;
	pid_t pid;

	pid = getpid();
	(void)signal(SIGTTOU, SIG_IGN);
	(void)signal(SIGURG, oob);
	(void)signal(SIGUSR1, oob); /* When propogating SIGURG from parent */
	ppid = getppid();
	(void)fcntl(rem, F_SETOWN, pid);
	(void)setjmp(rcvtop);
	(void)sigsetmask(omask);
	bufp = rcvbuf;
	for (;;) {
		while ((remaining = rcvcnt - (bufp - rcvbuf)) > 0) {
			rcvstate = WRITING;
			n = write(STDOUT_FILENO, bufp, remaining);
			if (n < 0) {
				if (errno != EINTR)
					return (-1);
				continue;
			}
			bufp += n;
		}
		bufp = rcvbuf;
		rcvcnt = 0;
		rcvstate = READING;

		rcvcnt = read(rem, rcvbuf, sizeof (rcvbuf));
		if (rcvcnt == 0)
			return (0);
		if (rcvcnt < 0) {
			if (errno == EINTR)
				continue;
			warn("read");
			return (-1);
		}
	}
}

void
mode(int f)
{
	struct termios tty;

	switch (f) {
	case 0:
		(void)tcsetattr(0, TCSANOW, &deftty);
		break;
	case 1:
		(void)tcgetattr(0, &deftty);
		tty = deftty;
		/* This is loosely derived from sys/kern/tty_compat.c. */
		tty.c_lflag &= ~(ECHO|ICANON|ISIG|IEXTEN);
		tty.c_iflag &= ~ICRNL;
		tty.c_oflag &= ~OPOST;
		tty.c_cc[VMIN] = 1;
		tty.c_cc[VTIME] = 0;
		if (eight) {
			tty.c_iflag &= IXOFF;
			tty.c_cflag &= ~(CSIZE|PARENB);
			tty.c_cflag |= CS8;
		}
		(void)tcsetattr(0, TCSANOW, &tty);
		break;
	default:
		return;
	}
}

/* ARGSUSED */
void
lostpeer(int signo __unused)
{
	(void)signal(SIGPIPE, SIG_IGN);
	msg("\007connection closed");
	done(1);
}

/* copy SIGURGs to the child process via SIGUSR1. */
/* ARGSUSED */
void
copytochild(int signo __unused)
{
	(void)kill(child, SIGUSR1);
}

void
msg(const char *str)
{
	(void)fprintf(stderr, "rlogin: %s\r\n", str);
}

void
usage(void)
{
	(void)fprintf(stderr,
	"usage: rlogin [-46%s]%s[-e char] [-i localname] [-l username] host\n",
	    "8DEd", " ");
	exit(1);
}

u_int
getescape(const char *p)
{
	long val;
	size_t len;

	if ((len = strlen(p)) == 1)	/* use any single char, including '\' */
		return ((u_int)*p);
					/* otherwise, \nnn */
	if (*p == '\\' && len >= 2 && len <= 4) {
		val = strtol(++p, NULL, 8);
		for (;;) {
			if (!*++p)
				return ((u_int)val);
			if (*p < '0' || *p > '8')
				break;
		}
	}
	msg("illegal option value -- e");
	usage();
	/* NOTREACHED */
}
OpenPOWER on IntegriCloud