xref: /netbsd-src/usr.bin/rlogin/rlogin.c (revision 5b182ca27f6c20e94a87cb39d0c0a626f6c4c7ce)
1 /*	$NetBSD: rlogin.c,v 1.48 2021/08/03 23:21:07 chs Exp $	*/
2 
3 /*
4  * Copyright (c) 1983, 1990, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. Neither the name of the University nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  */
31 
32 #include <sys/cdefs.h>
33 #ifndef lint
34 __COPYRIGHT("@(#) Copyright (c) 1983, 1990, 1993\
35  The Regents of the University of California.  All rights reserved.");
36 #endif /* not lint */
37 
38 #ifndef lint
39 #if 0
40 static char sccsid[] = "@(#)rlogin.c	8.4 (Berkeley) 4/29/95";
41 #else
42 __RCSID("$NetBSD: rlogin.c,v 1.48 2021/08/03 23:21:07 chs Exp $");
43 #endif
44 #endif /* not lint */
45 
46 /*
47  * rlogin - remote login
48  */
49 #include <sys/param.h>
50 #include <sys/ioctl.h>
51 #include <sys/socket.h>
52 #include <sys/time.h>
53 #include <sys/resource.h>
54 #include <sys/wait.h>
55 
56 #include <netinet/in.h>
57 #include <netinet/in_systm.h>
58 #include <netinet/ip.h>
59 #include <netinet/tcp.h>
60 
61 #include <err.h>
62 #include <errno.h>
63 #include <fcntl.h>
64 #include <netdb.h>
65 #include <pwd.h>
66 #include <setjmp.h>
67 #include <signal.h>
68 #include <stdarg.h>
69 #include <stdio.h>
70 #include <stdlib.h>
71 #include <string.h>
72 #include <termios.h>
73 #include <unistd.h>
74 
75 #include "getport.h"
76 
77 #ifndef TIOCPKT_WINDOW
78 #define	TIOCPKT_WINDOW	0x80
79 #endif
80 
81 /* concession to Sun */
82 #ifndef SIGUSR1
83 #define	SIGUSR1	30
84 #endif
85 
86 #ifndef CCEQ
87 #define CCEQ(val, c)	(c == val ? val != _POSIX_VDISABLE : 0)
88 #endif
89 
90 static int eight, rem;
91 static struct termios deftty;
92 
93 static int noescape;
94 static u_char escapechar = '~';
95 
96 #ifdef OLDSUN
97 struct winsize {
98 	unsigned short ws_row, ws_col;
99 	unsigned short ws_xpixel, ws_ypixel;
100 };
101 #else
102 #define	get_window_size(fd, wp)	ioctl(fd, TIOCGWINSZ, wp)
103 #endif
104 static struct	winsize winsize;
105 
106 static void		catch_child(int);
107 static void		copytochild(int);
108 __dead static void	doit(sigset_t *);
109 __dead static void	done(int);
110 static void		echo(int);
111 static u_int		getescape(char *);
112 __dead static void	lostpeer(int);
113 static void		mode(int);
114 static void		msg(const char *);
115 static void		oob(int);
116 static int		reader(sigset_t *);
117 static void		sendwindow(void);
118 static void		setsignal(int);
119 static void		sigwinch(int);
120 static void		stop(int);
121 __dead static void	usage(void);
122 static void		writer(void);
123 static void		writeroob(int);
124 
125 #ifdef OLDSUN
126 static int		get_window_size(int, struct winsize *);
127 #endif
128 
129 int
main(int argc,char * argv[])130 main(int argc, char *argv[])
131 {
132 	struct passwd *pw;
133 	struct servent *sp;
134 	struct termios tty;
135 	sigset_t imask, omask;
136 	uid_t uid;
137 	int argoff, ch, dflag, nflag, one;
138 	int i, len, len2;
139 	int family = AF_UNSPEC;
140 	char *host, *p, *user, *name, term[1024] = "network";
141 	speed_t ospeed;
142 	struct sigaction sa;
143 	char *service = NULL;
144 	struct rlimit rlim;
145 
146 	argoff = dflag = nflag = 0;
147 	one = 1;
148 	host = user = NULL;
149 	sp = NULL;
150 
151 	if (strcmp(getprogname(), "rlogin") != 0) {
152 		host = strdup(getprogname());
153 		if (host == NULL)
154 			err(1, NULL);
155 	}
156 
157 	/* handle "rlogin host flags" */
158 	if (!host && argc > 2 && argv[1][0] != '-') {
159 		host = argv[1];
160 		argoff = 1;
161 	}
162 
163 #define	OPTIONS	"468dEe:l:np:"
164 	while ((ch = getopt(argc - argoff, argv + argoff, OPTIONS)) != -1)
165 		switch(ch) {
166 		case '4':
167 			family = AF_INET;
168 			break;
169 		case '6':
170 			family = AF_INET6;
171 			break;
172 		case '8':
173 			eight = 1;
174 			break;
175 		case 'd':
176 			dflag = 1;
177 			break;
178 		case 'E':
179 			noescape = 1;
180 			break;
181 		case 'e':
182 			noescape = 0;
183 			escapechar = getescape(optarg);
184 			break;
185 		case 'l':
186 			user = optarg;
187 			break;
188 		case 'n':
189 			nflag = 1;
190 			break;
191 		case 'p':
192 			sp = getport(service = optarg, "tcp");
193 			break;
194 		case '?':
195 		default:
196 			usage();
197 		}
198 	optind += argoff;
199 	argc -= optind;
200 	argv += optind;
201 
202 	/* if haven't gotten a host yet, do so */
203 	if (!host && !(host = *argv++))
204 		usage();
205 
206 	if (*argv)
207 		usage();
208 
209 	if (!(pw = getpwuid(uid = getuid())))
210 		errx(1, "unknown user id.");
211 	/* Accept user1@host format, though "-l user2" overrides user1 */
212 	p = strchr(host, '@');
213 	if (p) {
214 		*p = '\0';
215 		if (!user && p > host)
216 			user = host;
217 		host = p + 1;
218 		if (*host == '\0')
219 			usage();
220 	}
221 	if ((name = strdup(pw->pw_name)) == NULL)
222 		err(1, "malloc");
223 	if (!user)
224 		user = name;
225 
226 	if (sp == NULL)
227 		sp = getservbyname("login", "tcp");
228 	if (sp == NULL)
229 		errx(1, "login/tcp: unknown service.");
230 
231 	if ((p = getenv("TERM")) != NULL)
232 		(void)strlcpy(term, p, sizeof(term));
233 	len = strlen(term);
234 	if (len < (int)(sizeof(term) - 1) && tcgetattr(0, &tty) == 0) {
235 		/* start at 2 to include the / */
236 		for (ospeed = i = cfgetospeed(&tty), len2 = 2; i > 9; len2++)
237 			i /= 10;
238 
239 		if (len + len2 < (int)sizeof(term))
240 			(void)snprintf(term + len, len2 + 1, "/%d", ospeed);
241 	}
242 
243 	(void)get_window_size(0, &winsize);
244 
245 	sigemptyset(&sa.sa_mask);
246 	sa.sa_flags = SA_RESTART;
247 	sa.sa_handler = lostpeer;
248 	(void)sigaction(SIGPIPE, &sa, NULL);
249 	/* will use SIGUSR1 for window size hack, so hold it off */
250 	sigemptyset(&imask);
251 	sigaddset(&imask, SIGURG);
252 	sigaddset(&imask, SIGUSR1);
253 	(void)sigprocmask(SIG_SETMASK, &imask, &omask);
254 	/*
255 	 * We set SIGURG and SIGUSR1 below so that an
256 	 * incoming signal will be held pending rather than being
257 	 * discarded. Note that these routines will be ready to get
258 	 * a signal by the time that they are unblocked below.
259 	 */
260 	sa.sa_handler = copytochild;
261 	(void)sigaction(SIGURG, &sa, NULL);
262 	sa.sa_handler = writeroob;
263 	(void)sigaction(SIGUSR1, &sa, NULL);
264 
265 	/* don't dump core */
266 	rlim.rlim_cur = rlim.rlim_max = 0;
267 	if (setrlimit(RLIMIT_CORE, &rlim) < 0)
268 		warn("setrlimit");
269 
270 	rem = rcmd_af(&host, sp->s_port, name, user, term, 0, family);
271 	if (rem < 0)
272 		exit(1);
273 
274 	if (dflag &&
275 	    setsockopt(rem, SOL_SOCKET, SO_DEBUG, &one, sizeof(one)) < 0)
276 		warn("setsockopt DEBUG (ignored)");
277 	if (nflag &&
278 	    setsockopt(rem, IPPROTO_TCP, TCP_NODELAY, &one, sizeof(one)) < 0)
279 		warn("setsockopt NODELAY (ignored)");
280 
281 	{
282 		struct sockaddr_storage ss;
283 		socklen_t sslen = sizeof(ss);
284 		if (getsockname(rem, (struct sockaddr *)&ss, &sslen) == 0
285 		     && ((struct sockaddr *)&ss)->sa_family == AF_INET) {
286 			one = IPTOS_LOWDELAY;
287 			if (setsockopt(rem, IPPROTO_IP, IP_TOS, (char *)&one,
288 			    sizeof(int)) < 0)
289 				warn("setsockopt TOS (ignored)");
290 		}
291 	}
292 
293 	(void)setuid(uid);
294 	doit(&omask);
295 	/*NOTREACHED*/
296 	return (0);
297 }
298 
299 static pid_t child;
300 
301 static void
doit(sigset_t * smask)302 doit(sigset_t *smask)
303 {
304 	struct sigaction sa;
305 
306 	sigemptyset(&sa.sa_mask);
307 	sa.sa_flags = SA_RESTART;
308 	sa.sa_handler = SIG_IGN;
309 	(void)sigaction(SIGINT, &sa, NULL);
310 	setsignal(SIGHUP);
311 	setsignal(SIGQUIT);
312 	mode(1);
313 	child = fork();
314 	if (child == -1) {
315 		warn("fork");
316 		done(1);
317 	}
318 	if (child == 0) {
319 		mode(1);
320 		if (reader(smask) == 0) {
321 			msg("connection closed.");
322 			exit(0);
323 		}
324 		sleep(1);
325 		msg("\aconnection closed.");
326 		exit(1);
327 	}
328 
329 	/*
330 	 * We may still own the socket, and may have a pending SIGURG (or might
331 	 * receive one soon) that we really want to send to the reader.  When
332 	 * one of these comes in, the trap copytochild simply copies such
333 	 * signals to the child. We can now unblock SIGURG and SIGUSR1
334 	 * that were set above.
335 	 */
336 	(void)sigprocmask(SIG_SETMASK, smask, NULL);
337 	sa.sa_handler = catch_child;
338 	(void)sigaction(SIGCHLD, &sa, NULL);
339 	writer();
340 	msg("closed connection.");
341 	done(0);
342 }
343 
344 /* trap a signal, unless it is being ignored. */
345 static void
setsignal(int sig)346 setsignal(int sig)
347 {
348 	struct sigaction isa, osa;
349 	sigset_t isigs, osigs;
350 
351 	sigemptyset(&isigs);
352 	sigaddset(&isigs, sig);
353 	sigprocmask(SIG_BLOCK, &isigs, &osigs);
354 
355 	sigemptyset(&isa.sa_mask);
356 	isa.sa_handler = exit;
357 	isa.sa_flags = SA_RESTART;
358 	(void)sigaction(sig, &isa, &osa);
359 	if (osa.sa_handler == SIG_IGN)
360 		(void)sigaction(sig, &osa, NULL);
361 
362 	(void)sigprocmask(SIG_SETMASK, &osigs, NULL);
363 }
364 
365 static void
done(int status)366 done(int status)
367 {
368 	pid_t w;
369 	int wstatus;
370 	struct sigaction sa;
371 
372 	mode(0);
373 	if (child > 0) {
374 		/* make sure catch_child does not snap it up */
375 		sigemptyset(&sa.sa_mask);
376 		sa.sa_handler = SIG_DFL;
377 		sa.sa_flags = 0;
378 		(void)sigaction(SIGCHLD, &sa, NULL);
379 		if (kill(child, SIGKILL) >= 0)
380 			while ((w = wait(&wstatus)) > 0 && w != child)
381 				continue;
382 	}
383 	exit(status);
384 }
385 
386 static int dosigwinch;
387 
388 /*
389  * This is called when the reader process gets the out-of-band (urgent)
390  * request to turn on the window-changing protocol.
391  */
392 static void
writeroob(int signo)393 writeroob(int signo)
394 {
395 	struct sigaction sa;
396 
397 	if (dosigwinch == 0) {
398 		sendwindow();
399 		sigemptyset(&sa.sa_mask);
400 		sa.sa_handler = sigwinch;
401 		sa.sa_flags = SA_RESTART;
402 		(void)sigaction(SIGWINCH, &sa, NULL);
403 	}
404 	dosigwinch = 1;
405 }
406 
407 static void
catch_child(int signo)408 catch_child(int signo)
409 {
410 	int status;
411 	pid_t pid;
412 
413 	for (;;) {
414 		pid = waitpid(-1, &status, WNOHANG|WUNTRACED);
415 		if (pid == 0)
416 			return;
417 		/* if the child (reader) dies, just quit */
418 		if (pid < 0 || (pid == child && !WIFSTOPPED(status)))
419 			done(WEXITSTATUS(status) | WTERMSIG(status));
420 	}
421 	/* NOTREACHED */
422 }
423 
424 /*
425  * writer: write to remote: 0 -> line.
426  * ~.				terminate
427  * ~^Z				suspend rlogin process.
428  * ~<delayed-suspend char>	suspend rlogin process, but leave reader alone.
429  */
430 static void
writer(void)431 writer(void)
432 {
433 	int bol, local;
434 	ssize_t n;
435 	char c;
436 
437 	bol = 1;			/* beginning of line */
438 	local = 0;
439 	for (;;) {
440 		n = read(STDIN_FILENO, &c, 1);
441 		if (n <= 0) {
442 			if (n < 0 && errno == EINTR)
443 				continue;
444 			break;
445 		}
446 		/*
447 		 * If we're at the beginning of the line and recognize a
448 		 * command character, then we echo locally.  Otherwise,
449 		 * characters are echo'd remotely.  If the command character
450 		 * is doubled, this acts as a force and local echo is
451 		 * suppressed.
452 		 */
453 		if (bol) {
454 			bol = 0;
455 			if (!noescape && c == escapechar) {
456 				local = 1;
457 				continue;
458 			}
459 		} else if (local) {
460 			local = 0;
461 			if (c == '.' || CCEQ(deftty.c_cc[VEOF], c)) {
462 				echo((int)c);
463 				break;
464 			}
465 			if (CCEQ(deftty.c_cc[VSUSP], c)) {
466 				bol = 1;
467 				echo((int)c);
468 				stop(1);
469 				continue;
470 			}
471 			if (CCEQ(deftty.c_cc[VDSUSP], c)) {
472 				bol = 1;
473 				echo((int)c);
474 				stop(0);
475 				continue;
476 			}
477 			if (c != escapechar) {
478 				(void)write(rem, &escapechar, 1);
479 			}
480 		}
481 
482 		if (write(rem, &c, 1) == 0) {
483 			msg("line gone");
484 			break;
485 		}
486 
487 		bol = CCEQ(deftty.c_cc[VKILL], c) ||
488 		    CCEQ(deftty.c_cc[VEOF], c) ||
489 		    CCEQ(deftty.c_cc[VINTR], c) ||
490 		    CCEQ(deftty.c_cc[VSUSP], c) ||
491 		    c == '\r' || c == '\n';
492 	}
493 }
494 
495 static void
echo(int i)496 echo(int i)
497 {
498 	char c = (char)i;
499 	char *p;
500 	char buf[8];
501 
502 	p = buf;
503 	c &= 0177;
504 	*p++ = escapechar;
505 	if (c < ' ') {
506 		*p++ = '^';
507 		*p++ = c + '@';
508 	} else if (c == 0177) {
509 		*p++ = '^';
510 		*p++ = '?';
511 	} else
512 		*p++ = c;
513 	*p++ = '\r';
514 	*p++ = '\n';
515 	(void)write(STDOUT_FILENO, buf, p - buf);
516 }
517 
518 static void
stop(int all)519 stop(int all)
520 {
521 	struct sigaction sa;
522 
523 	mode(0);
524 	sigemptyset(&sa.sa_mask);
525 	sa.sa_handler = SIG_IGN;
526 	sa.sa_flags = SA_RESTART;
527 	(void)sigaction(SIGCHLD, &sa, NULL);
528 	(void)kill(all ? 0 : getpid(), SIGTSTP);
529 	sa.sa_handler = catch_child;
530 	(void)sigaction(SIGCHLD, &sa, NULL);
531 	mode(1);
532 	sigwinch(0);			/* check for size changes */
533 }
534 
535 static void
sigwinch(int signo)536 sigwinch(int signo)
537 {
538 	struct winsize ws;
539 
540 	if (dosigwinch && get_window_size(0, &ws) == 0 &&
541 	    memcmp(&ws, &winsize, sizeof(ws))) {
542 		winsize = ws;
543 		sendwindow();
544 	}
545 }
546 
547 /*
548  * Send the window size to the server via the magic escape
549  */
550 static void
sendwindow(void)551 sendwindow(void)
552 {
553 	struct winsize *wp;
554 	char obuf[4 + sizeof (struct winsize)];
555 
556 	wp = (struct winsize *)(obuf+4);
557 	obuf[0] = 0377;
558 	obuf[1] = 0377;
559 	obuf[2] = 's';
560 	obuf[3] = 's';
561 	wp->ws_row = htons(winsize.ws_row);
562 	wp->ws_col = htons(winsize.ws_col);
563 	wp->ws_xpixel = htons(winsize.ws_xpixel);
564 	wp->ws_ypixel = htons(winsize.ws_ypixel);
565 
566 	(void)write(rem, obuf, sizeof(obuf));
567 }
568 
569 /*
570  * reader: read from remote: line -> 1
571  */
572 #define	READING	1
573 #define	WRITING	2
574 
575 static jmp_buf rcvtop;
576 static pid_t ppid;
577 static ssize_t rcvcnt, rcvstate;
578 static char rcvbuf[8 * 1024];
579 
580 static void
oob(int signo)581 oob(int signo)
582 {
583 	struct termios tty;
584 	int atmark;
585 	ssize_t n, rcvd;
586 	char waste[BUFSIZ], mark;
587 
588 	rcvd = 0;
589 	while (recv(rem, &mark, 1, MSG_OOB) == -1) {
590 		switch (errno) {
591 		case EWOULDBLOCK:
592 			/*
593 			 * Urgent data not here yet.  It may not be possible
594 			 * to send it yet if we are blocked for output and
595 			 * our input buffer is full.
596 			 */
597 			if (rcvcnt < (ssize_t)sizeof(rcvbuf)) {
598 				n = read(rem, rcvbuf + rcvcnt,
599 				    sizeof(rcvbuf) - rcvcnt);
600 				if (n <= 0)
601 					return;
602 				rcvd += n;
603 			} else {
604 				n = read(rem, waste, sizeof(waste));
605 				if (n <= 0)
606 					return;
607 			}
608 			continue;
609 		default:
610 			return;
611 		}
612 	}
613 	if (mark & TIOCPKT_WINDOW) {
614 		/* Let server know about window size changes */
615 		(void)kill(ppid, SIGUSR1);
616 	}
617 	if (!eight && (mark & TIOCPKT_NOSTOP)) {
618 		(void)tcgetattr(0, &tty);
619 		tty.c_iflag &= ~IXON;
620 		(void)tcsetattr(0, TCSANOW, &tty);
621 	}
622 	if (!eight && (mark & TIOCPKT_DOSTOP)) {
623 		(void)tcgetattr(0, &tty);
624 		tty.c_iflag |= (deftty.c_iflag & IXON);
625 		(void)tcsetattr(0, TCSANOW, &tty);
626 	}
627 	if (mark & TIOCPKT_FLUSHWRITE) {
628 		(void)tcflush(1, TCIOFLUSH);
629 		for (;;) {
630 			if (ioctl(rem, SIOCATMARK, &atmark) < 0) {
631 				warn("ioctl SIOCATMARK (ignored)");
632 				break;
633 			}
634 			if (atmark)
635 				break;
636 			n = read(rem, waste, sizeof (waste));
637 			if (n <= 0)
638 				break;
639 		}
640 		/*
641 		 * Don't want any pending data to be output, so clear the recv
642 		 * buffer.  If we were hanging on a write when interrupted,
643 		 * don't want it to restart.  If we were reading, restart
644 		 * anyway.
645 		 */
646 		rcvcnt = 0;
647 		longjmp(rcvtop, 1);
648 	}
649 
650 	/* oob does not do FLUSHREAD (alas!) */
651 
652 	/*
653 	 * If we filled the receive buffer while a read was pending, longjmp
654 	 * to the top to restart appropriately.  Don't abort a pending write,
655 	 * however, or we won't know how much was written.
656 	 */
657 	if (rcvd && rcvstate == READING)
658 		longjmp(rcvtop, 1);
659 }
660 
661 /* reader: read from remote: line -> 1 */
662 static int
reader(sigset_t * smask)663 reader(sigset_t *smask)
664 {
665 	pid_t pid;
666 	ssize_t n, remaining;
667 	char *bufp;
668 	struct sigaction sa;
669 
670 	pid = getpid();		/* modern systems use positives for pid */
671 	sigemptyset(&sa.sa_mask);
672 	sa.sa_flags = SA_RESTART;
673 	sa.sa_handler = SIG_IGN;
674 	(void)sigaction(SIGTTOU, &sa, NULL);
675 	sa.sa_handler = oob;
676 	(void)sigaction(SIGURG, &sa, NULL);
677 	ppid = getppid();
678 	(void)fcntl(rem, F_SETOWN, pid);
679 	(void)setjmp(rcvtop);
680 	(void)sigprocmask(SIG_SETMASK, smask, NULL);
681 	bufp = rcvbuf;
682 	for (;;) {
683 		while ((remaining = rcvcnt - (bufp - rcvbuf)) > 0) {
684 			rcvstate = WRITING;
685 			n = write(STDOUT_FILENO, bufp, remaining);
686 			if (n < 0) {
687 				if (errno != EINTR)
688 					return (-1);
689 				continue;
690 			}
691 			bufp += n;
692 		}
693 		bufp = rcvbuf;
694 		rcvcnt = 0;
695 		rcvstate = READING;
696 
697 		rcvcnt = read(rem, rcvbuf, sizeof (rcvbuf));
698 		if (rcvcnt == 0)
699 			return (0);
700 		if (rcvcnt < 0) {
701 			if (errno == EINTR)
702 				continue;
703 			warn("read");
704 			return (-1);
705 		}
706 	}
707 }
708 
709 static void
mode(int f)710 mode(int f)
711 {
712 	struct termios tty;
713 
714 	switch (f) {
715 	case 0:
716 		(void)tcsetattr(0, TCSANOW, &deftty);
717 		break;
718 	case 1:
719 		(void)tcgetattr(0, &deftty);
720 		tty = deftty;
721 		/* This is loosely derived from sys/compat/tty_compat.c. */
722 		tty.c_lflag &= ~(ECHO|ICANON|ISIG|IEXTEN);
723 		tty.c_iflag &= ~ICRNL;
724 		tty.c_oflag &= ~OPOST;
725 		tty.c_cc[VMIN] = 1;
726 		tty.c_cc[VTIME] = 0;
727 		if (eight) {
728 			tty.c_iflag &= IXOFF;
729 			tty.c_cflag &= ~(CSIZE|PARENB);
730 			tty.c_cflag |= CS8;
731 		}
732 		(void)tcsetattr(0, TCSANOW, &tty);
733 		break;
734 
735 	default:
736 		return;
737 	}
738 }
739 
740 static void
lostpeer(int signo)741 lostpeer(int signo)
742 {
743 	struct sigaction sa;
744 	sa.sa_flags = SA_RESTART;
745 	sa.sa_handler = SIG_IGN;
746 	sigemptyset(&sa.sa_mask);
747 	(void)sigaction(SIGPIPE, &sa, NULL);
748 	msg("\aconnection closed.");
749 	done(1);
750 }
751 
752 /* copy SIGURGs to the child process. */
753 static void
copytochild(int signo)754 copytochild(int signo)
755 {
756 
757 	(void)kill(child, SIGURG);
758 }
759 
760 static void
msg(const char * str)761 msg(const char *str)
762 {
763 
764 	(void)fprintf(stderr, "rlogin: %s\r\n", str);
765 }
766 
767 static void
usage(void)768 usage(void)
769 {
770 	(void)fprintf(stderr,
771 	    "Usage: %s [-468dEn] [-e char] [-l username] [-p port] "
772 	    "[username@]host\n", getprogname());
773 	exit(1);
774 }
775 
776 /*
777  * The following routine provides compatibility (such as it is) between older
778  * Suns and others.  Suns have only a `ttysize', so we convert it to a winsize.
779  */
780 #ifdef OLDSUN
781 static int
get_window_size(int fd,struct winsize * wp)782 get_window_size(int fd, struct winsize *wp)
783 {
784 	struct ttysize ts;
785 	int error;
786 
787 	if ((error = ioctl(0, TIOCGSIZE, &ts)) != 0)
788 		return (error);
789 	wp->ws_row = ts.ts_lines;
790 	wp->ws_col = ts.ts_cols;
791 	wp->ws_xpixel = 0;
792 	wp->ws_ypixel = 0;
793 	return (0);
794 }
795 #endif
796 
797 static u_int
getescape(char * p)798 getescape(char *p)
799 {
800 	long val;
801 	size_t len;
802 
803 	if ((len = strlen(p)) == 1)	/* use any single char, including '\' */
804 		return ((u_int)*p);
805 					/* otherwise, \nnn */
806 	if (*p == '\\' && len >= 2 && len <= 4) {
807 		val = strtol(++p, NULL, 8);
808 		for (;;) {
809 			if (!*++p)
810 				return ((u_int)val);
811 			if (*p < '0' || *p > '8')
812 				break;
813 		}
814 	}
815 	msg("illegal option value -- e");
816 	usage();
817 	/* NOTREACHED */
818 	return (0);
819 }
820