xref: /freebsd/libexec/getty/main.c (revision a07d59d1daafdaae0d1b1ad1f977f9eda92dc83b)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1980, 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 #ifndef lint
33 static const char copyright[] =
34 "@(#) Copyright (c) 1980, 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[] = "@(#)from: main.c	8.1 (Berkeley) 6/20/93";
41 #endif
42 #endif /* not lint */
43 #include <sys/cdefs.h>
44 __FBSDID("$FreeBSD$");
45 
46 #include <sys/param.h>
47 #include <sys/ioctl.h>
48 #include <sys/time.h>
49 #include <sys/resource.h>
50 #include <sys/stat.h>
51 #include <sys/ttydefaults.h>
52 #include <sys/utsname.h>
53 
54 #include <ctype.h>
55 #include <errno.h>
56 #include <fcntl.h>
57 #include <locale.h>
58 #include <libutil.h>
59 #include <setjmp.h>
60 #include <signal.h>
61 #include <stdlib.h>
62 #include <string.h>
63 #include <syslog.h>
64 #include <termios.h>
65 #include <time.h>
66 #include <unistd.h>
67 
68 #include "gettytab.h"
69 #include "extern.h"
70 #include "pathnames.h"
71 
72 /*
73  * Set the amount of running time that getty should accumulate
74  * before deciding that something is wrong and exit.
75  */
76 #define GETTY_TIMEOUT	60 /* seconds */
77 
78 #undef CTRL
79 #define CTRL(x)  (x&037)
80 
81 /* defines for auto detection of incoming PPP calls (->PAP/CHAP) */
82 
83 #define PPP_FRAME           0x7e  /* PPP Framing character */
84 #define PPP_STATION         0xff  /* "All Station" character */
85 #define PPP_ESCAPE          0x7d  /* Escape Character */
86 #define PPP_CONTROL         0x03  /* PPP Control Field */
87 #define PPP_CONTROL_ESCAPED 0x23  /* PPP Control Field, escaped */
88 #define PPP_LCP_HI          0xc0  /* LCP protocol - high byte */
89 #define PPP_LCP_LOW         0x21  /* LCP protocol - low byte */
90 
91 /* original mode; flags've been reset using values from <sys/ttydefaults.h> */
92 struct termios omode;
93 /* current mode */
94 struct termios tmode;
95 
96 static int crmod, digit, lower, upper;
97 
98 char	hostname[MAXHOSTNAMELEN];
99 static char	name[MAXLOGNAME*3];
100 static char	dev[] = _PATH_DEV;
101 static char	ttyn[32];
102 
103 #define	OBUFSIZ		128
104 #define	TABBUFSIZ	512
105 
106 static char	defent[TABBUFSIZ];
107 static char	tabent[TABBUFSIZ];
108 static const char	*tname;
109 
110 static char	*env[128];
111 
112 static char partab[] = {
113 	0001,0201,0201,0001,0201,0001,0001,0201,
114 	0202,0004,0003,0205,0005,0206,0201,0001,
115 	0201,0001,0001,0201,0001,0201,0201,0001,
116 	0001,0201,0201,0001,0201,0001,0001,0201,
117 	0200,0000,0000,0200,0000,0200,0200,0000,
118 	0000,0200,0200,0000,0200,0000,0000,0200,
119 	0000,0200,0200,0000,0200,0000,0000,0200,
120 	0200,0000,0000,0200,0000,0200,0200,0000,
121 	0200,0000,0000,0200,0000,0200,0200,0000,
122 	0000,0200,0200,0000,0200,0000,0000,0200,
123 	0000,0200,0200,0000,0200,0000,0000,0200,
124 	0200,0000,0000,0200,0000,0200,0200,0000,
125 	0000,0200,0200,0000,0200,0000,0000,0200,
126 	0200,0000,0000,0200,0000,0200,0200,0000,
127 	0200,0000,0000,0200,0000,0200,0200,0000,
128 	0000,0200,0200,0000,0200,0000,0000,0201
129 };
130 
131 #define	ERASE	tmode.c_cc[VERASE]
132 #define	KILL	tmode.c_cc[VKILL]
133 #define	EOT	tmode.c_cc[VEOF]
134 
135 #define	puts	Gputs
136 
137 static void	defttymode(void);
138 static void	dingdong(int);
139 static void	dogettytab(void);
140 static int	getname(void);
141 static void	interrupt(int);
142 static void	oflush(void);
143 static void	prompt(void);
144 static void	putchr(int);
145 static void	putf(const char *);
146 static void	putpad(const char *);
147 static void	puts(const char *);
148 static void	timeoverrun(int);
149 static char	*get_line(int);
150 static void	setttymode(int);
151 static int	opentty(const char *, int);
152 
153 static jmp_buf timeout;
154 
155 static void
156 dingdong(int signo __unused)
157 {
158 	alarm(0);
159 	longjmp(timeout, 1);
160 }
161 
162 static jmp_buf	intrupt;
163 
164 static void
165 interrupt(int signo __unused)
166 {
167 	longjmp(intrupt, 1);
168 }
169 
170 /*
171  * Action to take when getty is running too long.
172  */
173 static void
174 timeoverrun(int signo __unused)
175 {
176 
177 	syslog(LOG_ERR, "getty exiting due to excessive running time");
178 	exit(1);
179 }
180 
181 int
182 main(int argc, char *argv[])
183 {
184 	int first_sleep = 1, first_time = 1;
185 	struct rlimit limit;
186 	int rval;
187 
188 	signal(SIGINT, SIG_IGN);
189 	signal(SIGQUIT, SIG_IGN);
190 
191 	openlog("getty", LOG_CONS|LOG_PID, LOG_AUTH);
192 	gethostname(hostname, sizeof(hostname) - 1);
193 	hostname[sizeof(hostname) - 1] = '\0';
194 	if (hostname[0] == '\0')
195 		strcpy(hostname, "Amnesiac");
196 
197 	/*
198 	 * Limit running time to deal with broken or dead lines.
199 	 */
200 	(void)signal(SIGXCPU, timeoverrun);
201 	limit.rlim_max = RLIM_INFINITY;
202 	limit.rlim_cur = GETTY_TIMEOUT;
203 	(void)setrlimit(RLIMIT_CPU, &limit);
204 
205 	gettable("default", defent);
206 	gendefaults();
207 	tname = "default";
208 	if (argc > 1)
209 		tname = argv[1];
210 
211 	/*
212 	 * The following is a work around for vhangup interactions
213 	 * which cause great problems getting window systems started.
214 	 * If the tty line is "-", we do the old style getty presuming
215 	 * that the file descriptors are already set up for us.
216 	 * J. Gettys - MIT Project Athena.
217 	 */
218 	if (argc <= 2 || strcmp(argv[2], "-") == 0)
219 	    strcpy(ttyn, ttyname(STDIN_FILENO));
220 	else {
221 	    strcpy(ttyn, dev);
222 	    strncat(ttyn, argv[2], sizeof(ttyn)-sizeof(dev));
223 	    if (strcmp(argv[0], "+") != 0) {
224 		chown(ttyn, 0, 0);
225 		chmod(ttyn, 0600);
226 		revoke(ttyn);
227 
228 		/*
229 		 * Do the first scan through gettytab.
230 		 * Terminal mode parameters will be wrong until
231 		 * defttymode() called, but they're irrelevant for
232 		 * the initial setup of the terminal device.
233 		 */
234 		dogettytab();
235 
236 		/*
237 		 * Init or answer modem sequence has been specified.
238 		 */
239 		if (IC || AC) {
240 			if (!opentty(ttyn, O_RDWR|O_NONBLOCK))
241 				exit(1);
242 			defttymode();
243 			setttymode(1);
244 		}
245 
246 		if (IC) {
247 			if (getty_chat(IC, CT, DC) > 0) {
248 				syslog(LOG_ERR, "modem init problem on %s", ttyn);
249 				(void)tcsetattr(STDIN_FILENO, TCSANOW, &tmode);
250 				exit(1);
251 			}
252 		}
253 
254 		if (AC) {
255 			int i, rfds;
256 			struct timeval to;
257 
258         		rfds = 1 << 0;	/* FD_SET */
259         		to.tv_sec = RT;
260         		to.tv_usec = 0;
261         		i = select(32, (fd_set*)&rfds, (fd_set*)NULL,
262         			       (fd_set*)NULL, RT ? &to : NULL);
263         		if (i < 0) {
264 				syslog(LOG_ERR, "select %s: %m", ttyn);
265 			} else if (i == 0) {
266 				syslog(LOG_NOTICE, "recycle tty %s", ttyn);
267 				(void)tcsetattr(STDIN_FILENO, TCSANOW, &tmode);
268 				exit(0);  /* recycle for init */
269 			}
270 			i = getty_chat(AC, CT, DC);
271 			if (i > 0) {
272 				syslog(LOG_ERR, "modem answer problem on %s", ttyn);
273 				(void)tcsetattr(STDIN_FILENO, TCSANOW, &tmode);
274 				exit(1);
275 			}
276 		} else { /* maybe blocking open */
277 			if (!opentty(ttyn, O_RDWR | (NC ? O_NONBLOCK : 0 )))
278 				exit(1);
279 		}
280 	    }
281 	}
282 
283 	defttymode();
284 	for (;;) {
285 
286 		/*
287 		 * if a delay was specified then sleep for that
288 		 * number of seconds before writing the initial prompt
289 		 */
290 		if (first_sleep && DE) {
291 		    sleep(DE);
292 		    /* remove any noise */
293 		    (void)tcflush(STDIN_FILENO, TCIOFLUSH);
294 		}
295 		first_sleep = 0;
296 
297 		setttymode(0);
298 		if (AB) {
299 			tname = autobaud();
300 			dogettytab();
301 			continue;
302 		}
303 		if (PS) {
304 			tname = portselector();
305 			dogettytab();
306 			continue;
307 		}
308 		if (CL && *CL)
309 			putpad(CL);
310 		edithost(HE);
311 
312 		/* if this is the first time through this, and an
313 		   issue file has been given, then send it */
314 		if (first_time && IF) {
315 			int fd;
316 
317 			if ((fd = open(IF, O_RDONLY)) != -1) {
318 				char * cp;
319 
320 				while ((cp = get_line(fd)) != NULL) {
321 					  putf(cp);
322 				}
323 				close(fd);
324 			}
325 		}
326 		first_time = 0;
327 
328 		if (IMP && *IMP && !(PL && PP))
329 			system(IMP);
330 		if (IM && *IM && !(PL && PP))
331 			putf(IM);
332 		if (setjmp(timeout)) {
333 			cfsetispeed(&tmode, B0);
334 			cfsetospeed(&tmode, B0);
335 			(void)tcsetattr(STDIN_FILENO, TCSANOW, &tmode);
336 			exit(1);
337 		}
338 		if (TO) {
339 			signal(SIGALRM, dingdong);
340 			alarm(TO);
341 		}
342 
343 		rval = 0;
344 		if (AL) {
345 			const char *p = AL;
346 			char *q = name;
347 
348 			while (*p && q < &name[sizeof name - 1]) {
349 				if (isupper(*p))
350 					upper = 1;
351 				else if (islower(*p))
352 					lower = 1;
353 				else if (isdigit(*p))
354 					digit = 1;
355 				*q++ = *p++;
356 			}
357 		} else if (!(PL && PP))
358 			rval = getname();
359 		if (rval == 2 || (PL && PP)) {
360 			oflush();
361 			alarm(0);
362 			limit.rlim_max = RLIM_INFINITY;
363 			limit.rlim_cur = RLIM_INFINITY;
364 			(void)setrlimit(RLIMIT_CPU, &limit);
365 			execle(PP, "ppplogin", ttyn, (char *) 0, env);
366 			syslog(LOG_ERR, "%s: %m", PP);
367 			exit(1);
368 		} else if (rval || AL) {
369 			int i;
370 
371 			oflush();
372 			alarm(0);
373 			signal(SIGALRM, SIG_DFL);
374 			if (name[0] == '\0')
375 				continue;
376 			if (name[0] == '-') {
377 				puts("user names may not start with '-'.");
378 				continue;
379 			}
380 			if (!(upper || lower || digit)) {
381 				if (AL) {
382 					syslog(LOG_ERR,
383 					    "invalid auto-login name: %s", AL);
384 					exit(1);
385 				} else
386 					continue;
387 			}
388 			set_flags(2);
389 			if (crmod) {
390 				tmode.c_iflag |= ICRNL;
391 				tmode.c_oflag |= ONLCR;
392 			}
393 #if REALLY_OLD_TTYS
394 			if (upper || UC)
395 				tmode.sg_flags |= LCASE;
396 			if (lower || LC)
397 				tmode.sg_flags &= ~LCASE;
398 #endif
399 			if (tcsetattr(STDIN_FILENO, TCSANOW, &tmode) < 0) {
400 				syslog(LOG_ERR, "tcsetattr %s: %m", ttyn);
401 				exit(1);
402 			}
403 			signal(SIGINT, SIG_DFL);
404 			for (i = 0; environ[i] != (char *)0; i++)
405 				env[i] = environ[i];
406 			makeenv(&env[i]);
407 
408 			limit.rlim_max = RLIM_INFINITY;
409 			limit.rlim_cur = RLIM_INFINITY;
410 			(void)setrlimit(RLIMIT_CPU, &limit);
411 			execle(LO, "login", AL ? "-fp" : "-p", name,
412 			    (char *) 0, env);
413 			syslog(LOG_ERR, "%s: %m", LO);
414 			exit(1);
415 		}
416 		alarm(0);
417 		signal(SIGALRM, SIG_DFL);
418 		signal(SIGINT, SIG_IGN);
419 		if (NX && *NX) {
420 			tname = NX;
421 			dogettytab();
422 		}
423 	}
424 }
425 
426 static int
427 opentty(const char *tty, int flags)
428 {
429 	int i;
430 	int failopenlogged = 0;
431 
432 	while ((i = open(tty, flags)) == -1)
433 	{
434 		if (!failopenlogged) {
435 			syslog(LOG_ERR, "open %s: %m", tty);
436 			failopenlogged = 1;
437 		}
438 		sleep(60);
439 	}
440 	if (login_tty(i) < 0) {
441 		if (daemon(0,0) < 0) {
442 			syslog(LOG_ERR,"daemon: %m");
443 			close(i);
444 			return 0;
445 		}
446 		if (login_tty(i) < 0) {
447 			syslog(LOG_ERR, "login_tty %s: %m", tty);
448 			close(i);
449 			return 0;
450 		}
451 	}
452 	return 1;
453 }
454 
455 static void
456 defttymode(void)
457 {
458 	struct termios def;
459 
460 	/* Start with default tty settings. */
461 	if (tcgetattr(STDIN_FILENO, &tmode) < 0) {
462 		syslog(LOG_ERR, "tcgetattr %s: %m", ttyn);
463 		exit(1);
464 	}
465 	omode = tmode; /* fill c_cc for dogettytab() */
466 	dogettytab();
467 	/*
468 	 * Don't rely on the driver too much, and initialize crucial
469 	 * things according to <sys/ttydefaults.h>.  Avoid clobbering
470 	 * the c_cc[] settings however, the console drivers might wish
471 	 * to leave their idea of the preferred VERASE key value
472 	 * there.
473 	 */
474 	cfmakesane(&def);
475 	tmode.c_iflag = def.c_iflag;
476 	tmode.c_oflag = def.c_oflag;
477 	tmode.c_lflag = def.c_lflag;
478 	tmode.c_cflag = def.c_cflag;
479 	if (NC)
480 		tmode.c_cflag |= CLOCAL;
481 	omode = tmode;
482 }
483 
484 static void
485 setttymode(int raw)
486 {
487 	int off = 0;
488 
489 	(void)tcflush(STDIN_FILENO, TCIOFLUSH);	/* clear out the crap */
490 	ioctl(STDIN_FILENO, FIONBIO, &off);	/* turn off non-blocking mode */
491 	ioctl(STDIN_FILENO, FIOASYNC, &off);	/* ditto for async mode */
492 
493 	if (IS)
494 		cfsetispeed(&tmode, speed(IS));
495 	else if (SP)
496 		cfsetispeed(&tmode, speed(SP));
497 	if (OS)
498 		cfsetospeed(&tmode, speed(OS));
499 	else if (SP)
500 		cfsetospeed(&tmode, speed(SP));
501 	set_flags(0);
502 	setchars();
503 	if (raw)
504 		cfmakeraw(&tmode);
505 	if (tcsetattr(STDIN_FILENO, TCSANOW, &tmode) < 0) {
506 		syslog(LOG_ERR, "tcsetattr %s: %m", ttyn);
507 		exit(1);
508 	}
509 }
510 
511 
512 static int
513 getname(void)
514 {
515 	int c;
516 	char *np;
517 	unsigned char cs;
518 	int ppp_state = 0;
519 	int ppp_connection = 0;
520 
521 	/*
522 	 * Interrupt may happen if we use CBREAK mode
523 	 */
524 	if (setjmp(intrupt)) {
525 		signal(SIGINT, SIG_IGN);
526 		return (0);
527 	}
528 	signal(SIGINT, interrupt);
529 	set_flags(1);
530 	prompt();
531 	oflush();
532 	if (PF > 0) {
533 		sleep(PF);
534 		PF = 0;
535 	}
536 	if (tcsetattr(STDIN_FILENO, TCSANOW, &tmode) < 0) {
537 		syslog(LOG_ERR, "%s: %m", ttyn);
538 		exit(1);
539 	}
540 	crmod = digit = lower = upper = 0;
541 	np = name;
542 	for (;;) {
543 		oflush();
544 		if (read(STDIN_FILENO, &cs, 1) <= 0)
545 			exit(0);
546 		if ((c = cs&0177) == 0)
547 			return (0);
548 
549 		/* PPP detection state machine..
550 		   Look for sequences:
551 		   PPP_FRAME, PPP_STATION, PPP_ESCAPE, PPP_CONTROL_ESCAPED or
552 		   PPP_FRAME, PPP_STATION, PPP_CONTROL (deviant from RFC)
553 		   See RFC1662.
554 		   Derived from code from Michael Hancock, <michaelh@cet.co.jp>
555 		   and Erik 'PPP' Olson, <eriko@wrq.com>
556 		 */
557 
558 		if (PP && (cs == PPP_FRAME)) {
559 			ppp_state = 1;
560 		} else if (ppp_state == 1 && cs == PPP_STATION) {
561 			ppp_state = 2;
562 		} else if (ppp_state == 2 && cs == PPP_ESCAPE) {
563 			ppp_state = 3;
564 		} else if ((ppp_state == 2 && cs == PPP_CONTROL)
565 			|| (ppp_state == 3 && cs == PPP_CONTROL_ESCAPED)) {
566 			ppp_state = 4;
567 		} else if (ppp_state == 4 && cs == PPP_LCP_HI) {
568 			ppp_state = 5;
569 		} else if (ppp_state == 5 && cs == PPP_LCP_LOW) {
570 			ppp_connection = 1;
571 			break;
572 		} else {
573 			ppp_state = 0;
574 		}
575 
576 		if (c == EOT || c == CTRL('d'))
577 			exit(0);
578 		if (c == '\r' || c == '\n' || np >= &name[sizeof name-1]) {
579 			putf("\r\n");
580 			break;
581 		}
582 		if (islower(c))
583 			lower = 1;
584 		else if (isupper(c))
585 			upper = 1;
586 		else if (c == ERASE || c == '\b' || c == 0177) {
587 			if (np > name) {
588 				np--;
589 				if (cfgetospeed(&tmode) >= 1200)
590 					puts("\b \b");
591 				else
592 					putchr(cs);
593 			}
594 			continue;
595 		} else if (c == KILL || c == CTRL('u')) {
596 			putchr('\r');
597 			if (cfgetospeed(&tmode) < 1200)
598 				putchr('\n');
599 			/* this is the way they do it down under ... */
600 			else if (np > name)
601 				puts("                                     \r");
602 			prompt();
603 			digit = lower = upper = 0;
604 			np = name;
605 			continue;
606 		} else if (isdigit(c))
607 			digit = 1;
608 		if (IG && (c <= ' ' || c > 0176))
609 			continue;
610 		*np++ = c;
611 		putchr(cs);
612 	}
613 	signal(SIGINT, SIG_IGN);
614 	*np = 0;
615 	if (c == '\r')
616 		crmod = 1;
617 	if ((upper && !lower && !LC) || UC)
618 		for (np = name; *np; np++)
619 			if (isupper(*np))
620 				*np = tolower(*np);
621 	return (1 + ppp_connection);
622 }
623 
624 static void
625 putpad(const char *s)
626 {
627 	int pad = 0;
628 	speed_t ospeed = cfgetospeed(&tmode);
629 
630 	if (isdigit(*s)) {
631 		while (isdigit(*s)) {
632 			pad *= 10;
633 			pad += *s++ - '0';
634 		}
635 		pad *= 10;
636 		if (*s == '.' && isdigit(s[1])) {
637 			pad += s[1] - '0';
638 			s += 2;
639 		}
640 	}
641 
642 	puts(s);
643 	/*
644 	 * If no delay needed, or output speed is
645 	 * not comprehensible, then don't try to delay.
646 	 */
647 	if (pad == 0 || ospeed <= 0)
648 		return;
649 
650 	/*
651 	 * Round up by a half a character frame, and then do the delay.
652 	 * Too bad there are no user program accessible programmed delays.
653 	 * Transmitting pad characters slows many terminals down and also
654 	 * loads the system.
655 	 */
656 	pad = (pad * ospeed + 50000) / 100000;
657 	while (pad--)
658 		putchr(*PC);
659 }
660 
661 static void
662 puts(const char *s)
663 {
664 	while (*s)
665 		putchr(*s++);
666 }
667 
668 static char	outbuf[OBUFSIZ];
669 static int	obufcnt = 0;
670 
671 static void
672 putchr(int cc)
673 {
674 	char c;
675 
676 	c = cc;
677 	if (!NP) {
678 		c |= partab[c&0177] & 0200;
679 		if (OP)
680 			c ^= 0200;
681 	}
682 	if (!UB) {
683 		outbuf[obufcnt++] = c;
684 		if (obufcnt >= OBUFSIZ)
685 			oflush();
686 	} else
687 		write(STDOUT_FILENO, &c, 1);
688 }
689 
690 static void
691 oflush(void)
692 {
693 	if (obufcnt)
694 		write(STDOUT_FILENO, outbuf, obufcnt);
695 	obufcnt = 0;
696 }
697 
698 static void
699 prompt(void)
700 {
701 
702 	putf(LM);
703 	if (CO)
704 		putchr('\n');
705 }
706 
707 
708 static char *
709 get_line(int fd)
710 {
711 	int i = 0;
712 	static char linebuf[512];
713 
714 	/*
715 	 * This is certainly slow, but it avoids having to include
716 	 * stdio.h unnecessarily. Issue files should be small anyway.
717 	 */
718 	while (i < (sizeof linebuf - 3) && read(fd, linebuf+i, 1)==1) {
719 		if (linebuf[i] == '\n') {
720 			/* Don't rely on newline mode, assume raw */
721 			linebuf[i++] = '\r';
722 			linebuf[i++] = '\n';
723 			linebuf[i] = '\0';
724 			return linebuf;
725 		}
726 		++i;
727 	}
728 	linebuf[i] = '\0';
729 	return i ? linebuf : 0;
730 }
731 
732 static void
733 putf(const char *cp)
734 {
735 	time_t t;
736 	char *slash, db[100];
737 
738 	static struct utsname kerninfo;
739 
740 	if (!*kerninfo.sysname)
741 		uname(&kerninfo);
742 
743 	while (*cp) {
744 		if (*cp != '%') {
745 			putchr(*cp++);
746 			continue;
747 		}
748 		switch (*++cp) {
749 
750 		case 't':
751 			slash = strrchr(ttyn, '/');
752 			if (slash == (char *) 0)
753 				puts(ttyn);
754 			else
755 				puts(&slash[1]);
756 			break;
757 
758 		case 'h':
759 			puts(editedhost);
760 			break;
761 
762 		case 'd': {
763 			t = (time_t)0;
764 			(void)time(&t);
765 			if (Lo)
766 				(void)setlocale(LC_TIME, Lo);
767 			(void)strftime(db, sizeof(db), DF, localtime(&t));
768 			puts(db);
769 			break;
770 
771 		case 's':
772 			puts(kerninfo.sysname);
773 			break;
774 
775 		case 'm':
776 			puts(kerninfo.machine);
777 			break;
778 
779 		case 'r':
780 			puts(kerninfo.release);
781 			break;
782 
783 		case 'v':
784 			puts(kerninfo.version);
785 			break;
786 		}
787 
788 		case '%':
789 			putchr('%');
790 			break;
791 		}
792 		cp++;
793 	}
794 }
795 
796 /*
797  * Read a gettytab database entry and perform necessary quirks.
798  */
799 static void
800 dogettytab(void)
801 {
802 
803 	/* Read the database entry. */
804 	gettable(tname, tabent);
805 
806 	/*
807 	 * Avoid inheriting the parity values from the default entry
808 	 * if any of them is set in the current entry.
809 	 * Mixing different parity settings is unreasonable.
810 	 */
811 	if (OPset || EPset || APset || NPset)
812 		OPset = EPset = APset = NPset = 1;
813 
814 	/* Fill in default values for unset capabilities. */
815 	setdefaults();
816 }
817