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rlogin.c revision 1.36 
      1 /*	$NetBSD: rlogin.c,v 1.36 2006/03/23 23:44:15 wiz 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\n\
     35 	The Regents of the University of California.  All rights reserved.\n");
     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 1.36 2006/03/23 23:44:15 wiz 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 #include <sys/ioctl.h>
     56 
     57 #include <netinet/in.h>
     58 #include <netinet/in_systm.h>
     59 #include <netinet/ip.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 
     78 #ifndef TIOCPKT_WINDOW
     79 #define	TIOCPKT_WINDOW	0x80
     80 #endif
     81 
     82 /* concession to Sun */
     83 #ifndef SIGUSR1
     84 #define	SIGUSR1	30
     85 #endif
     86 
     87 #ifndef CCEQ
     88 #define CCEQ(val, c)	(c == val ? val != _POSIX_VDISABLE : 0)
     89 #endif
     90 
     91 int eight, rem;
     92 struct termios deftty;
     93 
     94 int noescape;
     95 u_char escapechar = '~';
     96 
     97 #ifdef OLDSUN
     98 struct winsize {
     99 	unsigned short ws_row, ws_col;
    100 	unsigned short ws_xpixel, ws_ypixel;
    101 };
    102 #else
    103 #define	get_window_size(fd, wp)	ioctl(fd, TIOCGWINSZ, wp)
    104 #endif
    105 struct	winsize winsize;
    106 
    107 void		catch_child(int);
    108 void		copytochild(int);
    109 void		doit(sigset_t *);
    110 void		done(int);
    111 void		echo(int);
    112 u_int		getescape(char *);
    113 void		lostpeer(int);
    114 int		main(int, char **);
    115 void		mode(int);
    116 void		msg(const char *);
    117 void		oob(int);
    118 int		reader(sigset_t *);
    119 void		sendwindow(void);
    120 void		setsignal(int);
    121 void		sigwinch(int);
    122 void		stop(int);
    123 void		usage(void);
    124 void		writer(void);
    125 void		writeroob(int);
    126 
    127 #ifdef OLDSUN
    128 int		get_window_size(int, struct winsize *);
    129 #endif
    130 
    131 int
    132 main(int argc, char *argv[])
    133 {
    134 	struct passwd *pw;
    135 	struct servent *sp;
    136 	struct termios tty;
    137 	sigset_t smask;
    138 	uid_t uid;
    139 	int argoff, ch, dflag, one;
    140 	int i, len, len2;
    141 	int family = AF_UNSPEC;
    142 	char *host, *p, *user, *name, term[1024] = "network";
    143 	speed_t ospeed;
    144 	struct sigaction sa;
    145 	char *service = NULL;
    146 	struct rlimit rlim;
    147 
    148 	argoff = dflag = 0;
    149 	one = 1;
    150 	host = user = NULL;
    151 	sp = NULL;
    152 
    153 	if (strcmp(getprogname(), "rlogin") != 0) {
    154 		host = strdup(getprogname());
    155 		if (host == NULL)
    156 			err(1, NULL);
    157 	}
    158 
    159 	/* handle "rlogin host flags" */
    160 	if (!host && argc > 2 && argv[1][0] != '-') {
    161 		host = argv[1];
    162 		argoff = 1;
    163 	}
    164 
    165 #define	OPTIONS	"468dEe:l:p:"
    166 	while ((ch = getopt(argc - argoff, argv + argoff, OPTIONS)) != -1)
    167 		switch(ch) {
    168 		case '4':
    169 			family = AF_INET;
    170 			break;
    171 		case '6':
    172 			family = AF_INET6;
    173 			break;
    174 		case '8':
    175 			eight = 1;
    176 			break;
    177 		case 'd':
    178 			dflag = 1;
    179 			break;
    180 		case 'E':
    181 			noescape = 1;
    182 			break;
    183 		case 'e':
    184 			noescape = 0;
    185 			escapechar = getescape(optarg);
    186 			break;
    187 		case 'l':
    188 			user = optarg;
    189 			break;
    190 		case 'p':
    191 			sp = getport(service = optarg, "tcp");
    192 			break;
    193 		case '?':
    194 		default:
    195 			usage();
    196 		}
    197 	optind += argoff;
    198 	argc -= optind;
    199 	argv += optind;
    200 
    201 	/* if haven't gotten a host yet, do so */
    202 	if (!host && !(host = *argv++))
    203 		usage();
    204 
    205 	if (*argv)
    206 		usage();
    207 
    208 	if (!(pw = getpwuid(uid = getuid())))
    209 		errx(1, "unknown user id.");
    210 	/* Accept user1@host format, though "-l user2" overrides user1 */
    211 	p = strchr(host, '@');
    212 	if (p) {
    213 		*p = '\0';
    214 		if (!user && p > host)
    215 			user = host;
    216 		host = p + 1;
    217 		if (*host == '\0')
    218 			usage();
    219 	}
    220 	if ((name = strdup(pw->pw_name)) == NULL)
    221 		err(1, "malloc");
    222 	if (!user)
    223 		user = name;
    224 
    225 	if (sp == NULL)
    226 		sp = getservbyname("login", "tcp");
    227 	if (sp == NULL)
    228 		errx(1, "login/tcp: unknown service.");
    229 
    230 	if ((p = getenv("TERM")) != NULL)
    231 		(void)strlcpy(term, p, sizeof(term));
    232 	len = strlen(term);
    233 	if (len < (sizeof(term) - 1) && tcgetattr(0, &tty) == 0) {
    234 		/* start at 2 to include the / */
    235 		for (ospeed = i = cfgetospeed(&tty), len2 = 2; i > 9; len2++)
    236 			i /= 10;
    237 
    238 		if (len + len2 < sizeof(term))
    239 			(void)snprintf(term + len, len2 + 1, "/%d", ospeed);
    240 	}
    241 
    242 	(void)get_window_size(0, &winsize);
    243 
    244 	sigemptyset(&sa.sa_mask);
    245 	sa.sa_flags = SA_RESTART;
    246 	sa.sa_handler = lostpeer;
    247 	(void)sigaction(SIGPIPE, &sa, (struct sigaction *)0);
    248 	/* will use SIGUSR1 for window size hack, so hold it off */
    249 	sigemptyset(&smask);
    250 	sigaddset(&smask, SIGURG);
    251 	sigaddset(&smask, SIGUSR1);
    252 	(void)sigprocmask(SIG_SETMASK, &smask, &smask);
    253 	/*
    254 	 * We set SIGURG and SIGUSR1 below so that an
    255 	 * incoming signal will be held pending rather than being
    256 	 * discarded. Note that these routines will be ready to get
    257 	 * a signal by the time that they are unblocked below.
    258 	 */
    259 	sa.sa_handler = copytochild;
    260 	(void)sigaction(SIGURG, &sa, (struct sigaction *) 0);
    261 	sa.sa_handler = writeroob;
    262 	(void)sigaction(SIGUSR1, &sa, (struct sigaction *) 0);
    263 
    264 	/* don't dump core */
    265 	rlim.rlim_cur = rlim.rlim_max = 0;
    266 	if (setrlimit(RLIMIT_CORE, &rlim) < 0)
    267 		warn("setrlimit");
    268 
    269 	rem = rcmd_af(&host, sp->s_port, name, user, term, 0, family);
    270 
    271 
    272 	if (rem < 0)
    273 		exit(1);
    274 
    275 	if (dflag &&
    276 	    setsockopt(rem, SOL_SOCKET, SO_DEBUG, &one, sizeof(one)) < 0)
    277 		warn("setsockopt DEBUG (ignored)");
    278     {
    279 	struct sockaddr_storage ss;
    280 	int sslen;
    281 	sslen = sizeof(ss);
    282 	if (getsockname(rem, (struct sockaddr *)&ss, &sslen) == 0
    283 	 && ((struct sockaddr *)&ss)->sa_family == AF_INET) {
    284 		one = IPTOS_LOWDELAY;
    285 		if (setsockopt(rem, IPPROTO_IP, IP_TOS, (char *)&one,
    286 				sizeof(int)) < 0) {
    287 			warn("setsockopt TOS (ignored)");
    288 		}
    289 	}
    290     }
    291 
    292 	(void)setuid(uid);
    293 	doit(&smask);
    294 	/*NOTREACHED*/
    295 	return (0);
    296 }
    297 
    298 pid_t child;
    299 
    300 void
    301 doit(sigset_t *smask)
    302 {
    303 	struct sigaction sa;
    304 
    305 	sigemptyset(&sa.sa_mask);
    306 	sa.sa_flags = SA_RESTART;
    307 	sa.sa_handler = SIG_IGN;
    308 	(void)sigaction(SIGINT, &sa, (struct sigaction *) 0);
    309 	setsignal(SIGHUP);
    310 	setsignal(SIGQUIT);
    311 	mode(1);
    312 	child = fork();
    313 	if (child == -1) {
    314 		warn("fork");
    315 		done(1);
    316 	}
    317 	if (child == 0) {
    318 		mode(1);
    319 		if (reader(smask) == 0) {
    320 			msg("connection closed.");
    321 			exit(0);
    322 		}
    323 		sleep(1);
    324 		msg("\aconnection closed.");
    325 		exit(1);
    326 	}
    327 
    328 	/*
    329 	 * We may still own the socket, and may have a pending SIGURG (or might
    330 	 * receive one soon) that we really want to send to the reader.  When
    331 	 * one of these comes in, the trap copytochild simply copies such
    332 	 * signals to the child. We can now unblock SIGURG and SIGUSR1
    333 	 * that were set above.
    334 	 */
    335 	(void)sigprocmask(SIG_SETMASK, smask, (sigset_t *) 0);
    336 	sa.sa_handler = catch_child;
    337 	(void)sigaction(SIGCHLD, &sa, (struct sigaction *) 0);
    338 	writer();
    339 	msg("closed connection.");
    340 	done(0);
    341 }
    342 
    343 /* trap a signal, unless it is being ignored. */
    344 void
    345 setsignal(int sig)
    346 {
    347 	struct sigaction sa;
    348 	sigset_t sigs;
    349 
    350 	sigemptyset(&sigs);
    351 	sigaddset(&sigs, sig);
    352 	sigprocmask(SIG_BLOCK, &sigs, &sigs);
    353 
    354 	sigemptyset(&sa.sa_mask);
    355 	sa.sa_handler = exit;
    356 	sa.sa_flags = SA_RESTART;
    357 	(void)sigaction(sig, &sa, &sa);
    358 	if (sa.sa_handler == SIG_IGN)
    359 		(void)sigaction(sig, &sa, (struct sigaction *) 0);
    360 
    361 	(void)sigprocmask(SIG_SETMASK, &sigs, (sigset_t *) 0);
    362 }
    363 
    364 void
    365 done(int status)
    366 {
    367 	pid_t w;
    368 	int wstatus;
    369 	struct sigaction sa;
    370 
    371 	mode(0);
    372 	if (child > 0) {
    373 		/* make sure catch_child does not snap it up */
    374 		sigemptyset(&sa.sa_mask);
    375 		sa.sa_handler = SIG_DFL;
    376 		sa.sa_flags = 0;
    377 		(void)sigaction(SIGCHLD, &sa, (struct sigaction *) 0);
    378 		if (kill(child, SIGKILL) >= 0)
    379 			while ((w = wait(&wstatus)) > 0 && w != child)
    380 				continue;
    381 	}
    382 	exit(status);
    383 }
    384 
    385 int dosigwinch;
    386 
    387 /*
    388  * This is called when the reader process gets the out-of-band (urgent)
    389  * request to turn on the window-changing protocol.
    390  */
    391 void
    392 writeroob(int signo)
    393 {
    394 	struct sigaction sa;
    395 
    396 	if (dosigwinch == 0) {
    397 		sendwindow();
    398 		sigemptyset(&sa.sa_mask);
    399 		sa.sa_handler = sigwinch;
    400 		sa.sa_flags = SA_RESTART;
    401 		(void)sigaction(SIGWINCH, &sa, (struct sigaction *) 0);
    402 	}
    403 	dosigwinch = 1;
    404 }
    405 
    406 void
    407 catch_child(int signo)
    408 {
    409 	int status;
    410 	pid_t pid;
    411 
    412 	for (;;) {
    413 		pid = waitpid(-1, &status, WNOHANG|WUNTRACED);
    414 		if (pid == 0)
    415 			return;
    416 		/* if the child (reader) dies, just quit */
    417 		if (pid < 0 || (pid == child && !WIFSTOPPED(status)))
    418 			done(WEXITSTATUS(status) | WTERMSIG(status));
    419 	}
    420 	/* NOTREACHED */
    421 }
    422 
    423 /*
    424  * writer: write to remote: 0 -> line.
    425  * ~.				terminate
    426  * ~^Z				suspend rlogin process.
    427  * ~<delayed-suspend char>	suspend rlogin process, but leave reader alone.
    428  */
    429 void
    430 writer(void)
    431 {
    432 	int bol, local, n;
    433 	char c;
    434 
    435 	bol = 1;			/* beginning of line */
    436 	local = 0;
    437 	for (;;) {
    438 		n = read(STDIN_FILENO, &c, 1);
    439 		if (n <= 0) {
    440 			if (n < 0 && errno == EINTR)
    441 				continue;
    442 			break;
    443 		}
    444 		/*
    445 		 * If we're at the beginning of the line and recognize a
    446 		 * command character, then we echo locally.  Otherwise,
    447 		 * characters are echo'd remotely.  If the command character
    448 		 * is doubled, this acts as a force and local echo is
    449 		 * suppressed.
    450 		 */
    451 		if (bol) {
    452 			bol = 0;
    453 			if (!noescape && c == escapechar) {
    454 				local = 1;
    455 				continue;
    456 			}
    457 		} else if (local) {
    458 			local = 0;
    459 			if (c == '.' || CCEQ(deftty.c_cc[VEOF], c)) {
    460 				echo((int)c);
    461 				break;
    462 			}
    463 			if (CCEQ(deftty.c_cc[VSUSP], c)) {
    464 				bol = 1;
    465 				echo((int)c);
    466 				stop(1);
    467 				continue;
    468 			}
    469 			if (CCEQ(deftty.c_cc[VDSUSP], c)) {
    470 				bol = 1;
    471 				echo((int)c);
    472 				stop(0);
    473 				continue;
    474 			}
    475 			if (c != escapechar) {
    476 					(void)write(rem, &escapechar, 1);
    477 			}
    478 		}
    479 
    480 			if (write(rem, &c, 1) == 0) {
    481 				msg("line gone");
    482 				break;
    483 			}
    484 
    485 		bol = CCEQ(deftty.c_cc[VKILL], c) ||
    486 		    CCEQ(deftty.c_cc[VEOF], c) ||
    487 		    CCEQ(deftty.c_cc[VINTR], c) ||
    488 		    CCEQ(deftty.c_cc[VSUSP], c) ||
    489 		    c == '\r' || c == '\n';
    490 	}
    491 }
    492 
    493 void
    494 echo(int i)
    495 {
    496 	char c = (char)i;
    497 	char *p;
    498 	char buf[8];
    499 
    500 	p = buf;
    501 	c &= 0177;
    502 	*p++ = escapechar;
    503 	if (c < ' ') {
    504 		*p++ = '^';
    505 		*p++ = c + '@';
    506 	} else if (c == 0177) {
    507 		*p++ = '^';
    508 		*p++ = '?';
    509 	} else
    510 		*p++ = c;
    511 	*p++ = '\r';
    512 	*p++ = '\n';
    513 	(void)write(STDOUT_FILENO, buf, p - buf);
    514 }
    515 
    516 void
    517 stop(int all)
    518 {
    519 	struct sigaction sa;
    520 
    521 	mode(0);
    522 	sigemptyset(&sa.sa_mask);
    523 	sa.sa_handler = SIG_IGN;
    524 	sa.sa_flags = SA_RESTART;
    525 	(void)sigaction(SIGCHLD, &sa, (struct sigaction *) 0);
    526 	(void)kill(all ? 0 : getpid(), SIGTSTP);
    527 	sa.sa_handler = catch_child;
    528 	(void)sigaction(SIGCHLD, &sa, (struct sigaction *) 0);
    529 	mode(1);
    530 	sigwinch(0);			/* check for size changes */
    531 }
    532 
    533 void
    534 sigwinch(int signo)
    535 {
    536 	struct winsize ws;
    537 
    538 	if (dosigwinch && get_window_size(0, &ws) == 0 &&
    539 	    memcmp(&ws, &winsize, sizeof(ws))) {
    540 		winsize = ws;
    541 		sendwindow();
    542 	}
    543 }
    544 
    545 /*
    546  * Send the window size to the server via the magic escape
    547  */
    548 void
    549 sendwindow(void)
    550 {
    551 	struct winsize *wp;
    552 	char obuf[4 + sizeof (struct winsize)];
    553 
    554 	wp = (struct winsize *)(obuf+4);
    555 	obuf[0] = 0377;
    556 	obuf[1] = 0377;
    557 	obuf[2] = 's';
    558 	obuf[3] = 's';
    559 	wp->ws_row = htons(winsize.ws_row);
    560 	wp->ws_col = htons(winsize.ws_col);
    561 	wp->ws_xpixel = htons(winsize.ws_xpixel);
    562 	wp->ws_ypixel = htons(winsize.ws_ypixel);
    563 
    564 		(void)write(rem, obuf, sizeof(obuf));
    565 }
    566 
    567 /*
    568  * reader: read from remote: line -> 1
    569  */
    570 #define	READING	1
    571 #define	WRITING	2
    572 
    573 jmp_buf rcvtop;
    574 pid_t ppid;
    575 int rcvcnt, rcvstate;
    576 char rcvbuf[8 * 1024];
    577 
    578 void
    579 oob(int signo)
    580 {
    581 	struct termios tty;
    582 	int atmark, n, rcvd;
    583 	char waste[BUFSIZ], mark;
    584 
    585 	rcvd = 0;
    586 	while (recv(rem, &mark, 1, MSG_OOB) < 0) {
    587 		switch (errno) {
    588 		case EWOULDBLOCK:
    589 			/*
    590 			 * Urgent data not here yet.  It may not be possible
    591 			 * to send it yet if we are blocked for output and
    592 			 * our input buffer is full.
    593 			 */
    594 			if (rcvcnt < sizeof(rcvbuf)) {
    595 				n = read(rem, rcvbuf + rcvcnt,
    596 				    sizeof(rcvbuf) - rcvcnt);
    597 				if (n <= 0)
    598 					return;
    599 				rcvd += n;
    600 			} else {
    601 				n = read(rem, waste, sizeof(waste));
    602 				if (n <= 0)
    603 					return;
    604 			}
    605 			continue;
    606 		default:
    607 			return;
    608 		}
    609 	}
    610 	if (mark & TIOCPKT_WINDOW) {
    611 		/* Let server know about window size changes */
    612 		(void)kill(ppid, SIGUSR1);
    613 	}
    614 	if (!eight && (mark & TIOCPKT_NOSTOP)) {
    615 		(void)tcgetattr(0, &tty);
    616 		tty.c_iflag &= ~IXON;
    617 		(void)tcsetattr(0, TCSANOW, &tty);
    618 	}
    619 	if (!eight && (mark & TIOCPKT_DOSTOP)) {
    620 		(void)tcgetattr(0, &tty);
    621 		tty.c_iflag |= (deftty.c_iflag & IXON);
    622 		(void)tcsetattr(0, TCSANOW, &tty);
    623 	}
    624 	if (mark & TIOCPKT_FLUSHWRITE) {
    625 		(void)tcflush(1, TCIOFLUSH);
    626 		for (;;) {
    627 			if (ioctl(rem, SIOCATMARK, &atmark) < 0) {
    628 				warn("ioctl SIOCATMARK (ignored)");
    629 				break;
    630 			}
    631 			if (atmark)
    632 				break;
    633 			n = read(rem, waste, sizeof (waste));
    634 			if (n <= 0)
    635 				break;
    636 		}
    637 		/*
    638 		 * Don't want any pending data to be output, so clear the recv
    639 		 * buffer.  If we were hanging on a write when interrupted,
    640 		 * don't want it to restart.  If we were reading, restart
    641 		 * anyway.
    642 		 */
    643 		rcvcnt = 0;
    644 		longjmp(rcvtop, 1);
    645 	}
    646 
    647 	/* oob does not do FLUSHREAD (alas!) */
    648 
    649 	/*
    650 	 * If we filled the receive buffer while a read was pending, longjmp
    651 	 * to the top to restart appropriately.  Don't abort a pending write,
    652 	 * however, or we won't know how much was written.
    653 	 */
    654 	if (rcvd && rcvstate == READING)
    655 		longjmp(rcvtop, 1);
    656 }
    657 
    658 /* reader: read from remote: line -> 1 */
    659 int
    660 reader(sigset_t *smask)
    661 {
    662 	pid_t pid;
    663 	int n, remaining;
    664 	char *bufp;
    665 	struct sigaction sa;
    666 
    667 	pid = getpid();		/* modern systems use positives for pid */
    668 	sigemptyset(&sa.sa_mask);
    669 	sa.sa_flags = SA_RESTART;
    670 	sa.sa_handler = SIG_IGN;
    671 	(void)sigaction(SIGTTOU, &sa, (struct sigaction *) 0);
    672 	sa.sa_handler = oob;
    673 	(void)sigaction(SIGURG, &sa, (struct sigaction *) 0);
    674 	ppid = getppid();
    675 	(void)fcntl(rem, F_SETOWN, pid);
    676 	(void)setjmp(rcvtop);
    677 	(void)sigprocmask(SIG_SETMASK, smask, (sigset_t *) 0);
    678 	bufp = rcvbuf;
    679 	for (;;) {
    680 		while ((remaining = rcvcnt - (bufp - rcvbuf)) > 0) {
    681 			rcvstate = WRITING;
    682 			n = write(STDOUT_FILENO, bufp, remaining);
    683 			if (n < 0) {
    684 				if (errno != EINTR)
    685 					return (-1);
    686 				continue;
    687 			}
    688 			bufp += n;
    689 		}
    690 		bufp = rcvbuf;
    691 		rcvcnt = 0;
    692 		rcvstate = READING;
    693 
    694 			rcvcnt = read(rem, rcvbuf, sizeof (rcvbuf));
    695 
    696 		if (rcvcnt == 0)
    697 			return (0);
    698 		if (rcvcnt < 0) {
    699 			if (errno == EINTR)
    700 				continue;
    701 			warn("read");
    702 			return (-1);
    703 		}
    704 	}
    705 }
    706 
    707 void
    708 mode(int f)
    709 {
    710 	struct termios tty;
    711 
    712 	switch (f) {
    713 	case 0:
    714 		(void)tcsetattr(0, TCSANOW, &deftty);
    715 		break;
    716 	case 1:
    717 		(void)tcgetattr(0, &deftty);
    718 		tty = deftty;
    719 		/* This is loosely derived from sys/compat/tty_compat.c. */
    720 		tty.c_lflag &= ~(ECHO|ICANON|ISIG|IEXTEN);
    721 		tty.c_iflag &= ~ICRNL;
    722 		tty.c_oflag &= ~OPOST;
    723 		tty.c_cc[VMIN] = 1;
    724 		tty.c_cc[VTIME] = 0;
    725 		if (eight) {
    726 			tty.c_iflag &= IXOFF;
    727 			tty.c_cflag &= ~(CSIZE|PARENB);
    728 			tty.c_cflag |= CS8;
    729 		}
    730 		(void)tcsetattr(0, TCSANOW, &tty);
    731 		break;
    732 
    733 	default:
    734 		return;
    735 	}
    736 }
    737 
    738 void
    739 lostpeer(int signo)
    740 {
    741 	struct sigaction sa;
    742 	sa.sa_flags = SA_RESTART;
    743 	sa.sa_handler = SIG_IGN;
    744 	(void)sigaction(SIGPIPE, &sa, (struct sigaction *)0);
    745 	msg("\aconnection closed.");
    746 	done(1);
    747 }
    748 
    749 /* copy SIGURGs to the child process. */
    750 void
    751 copytochild(int signo)
    752 {
    753 
    754 	(void)kill(child, SIGURG);
    755 }
    756 
    757 void
    758 msg(const char *str)
    759 {
    760 
    761 	(void)fprintf(stderr, "rlogin: %s\r\n", str);
    762 }
    763 
    764 
    765 void
    766 usage(void)
    767 {
    768 	(void)fprintf(stderr,
    769 	    "usage: rlogin [-%s]%s[-e char] [-l username] [-p port] [username@]host\n",
    770 	    "468Ed", " ");
    771 	exit(1);
    772 }
    773 
    774 /*
    775  * The following routine provides compatibility (such as it is) between older
    776  * Suns and others.  Suns have only a `ttysize', so we convert it to a winsize.
    777  */
    778 #ifdef OLDSUN
    779 int
    780 get_window_size(fd, wp)
    781 	int fd;
    782 	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 u_int
    798 getescape(char *p)
    799 {
    800 	long val;
    801 	int 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