xref: /freebsd/libexec/getty/main.c (revision ec965063070e5753c166cf592c9336444b74720a)
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 <stdio.h>
62 #include <stdlib.h>
63 #include <string.h>
64 #include <syslog.h>
65 #include <termios.h>
66 #include <time.h>
67 #include <unistd.h>
68 
69 #include "gettytab.h"
70 #include "extern.h"
71 #include "pathnames.h"
72 
73 /*
74  * Set the amount of running time that getty should accumulate
75  * before deciding that something is wrong and exit.
76  */
77 #define GETTY_TIMEOUT	60 /* seconds */
78 
79 #undef CTRL
80 #define CTRL(x)  (x&037)
81 
82 /* defines for auto detection of incoming PPP calls (->PAP/CHAP) */
83 
84 #define PPP_FRAME           0x7e  /* PPP Framing character */
85 #define PPP_STATION         0xff  /* "All Station" character */
86 #define PPP_ESCAPE          0x7d  /* Escape Character */
87 #define PPP_CONTROL         0x03  /* PPP Control Field */
88 #define PPP_CONTROL_ESCAPED 0x23  /* PPP Control Field, escaped */
89 #define PPP_LCP_HI          0xc0  /* LCP protocol - high byte */
90 #define PPP_LCP_LOW         0x21  /* LCP protocol - low byte */
91 
92 /* original mode; flags've been reset using values from <sys/ttydefaults.h> */
93 struct termios omode;
94 /* current mode */
95 struct termios tmode;
96 
97 static int crmod, digit, lower, upper;
98 
99 char	hostname[MAXHOSTNAMELEN];
100 static char	name[MAXLOGNAME*3];
101 static char	ttyn[32];
102 
103 #define	OBUFSIZ		128
104 
105 static const char	*tname;
106 
107 static char	*env[128];
108 
109 static char partab[] = {
110 	0001,0201,0201,0001,0201,0001,0001,0201,
111 	0202,0004,0003,0205,0005,0206,0201,0001,
112 	0201,0001,0001,0201,0001,0201,0201,0001,
113 	0001,0201,0201,0001,0201,0001,0001,0201,
114 	0200,0000,0000,0200,0000,0200,0200,0000,
115 	0000,0200,0200,0000,0200,0000,0000,0200,
116 	0000,0200,0200,0000,0200,0000,0000,0200,
117 	0200,0000,0000,0200,0000,0200,0200,0000,
118 	0200,0000,0000,0200,0000,0200,0200,0000,
119 	0000,0200,0200,0000,0200,0000,0000,0200,
120 	0000,0200,0200,0000,0200,0000,0000,0200,
121 	0200,0000,0000,0200,0000,0200,0200,0000,
122 	0000,0200,0200,0000,0200,0000,0000,0200,
123 	0200,0000,0000,0200,0000,0200,0200,0000,
124 	0200,0000,0000,0200,0000,0200,0200,0000,
125 	0000,0200,0200,0000,0200,0000,0000,0201
126 };
127 
128 #define	ERASE	tmode.c_cc[VERASE]
129 #define	KILL	tmode.c_cc[VKILL]
130 #define	EOT	tmode.c_cc[VEOF]
131 
132 #define	puts	Gputs
133 
134 static void	defttymode(void);
135 static void	dingdong(int);
136 static void	dogettytab(void);
137 static int	getname(void);
138 static void	interrupt(int);
139 static void	oflush(void);
140 static void	prompt(void);
141 static void	putchr(int);
142 static void	putf(const char *);
143 static void	putpad(const char *);
144 static void	puts(const char *);
145 static void	timeoverrun(int);
146 static char	*get_line(int);
147 static void	setttymode(int);
148 static int	opentty(const char *, int);
149 
150 static jmp_buf timeout;
151 
152 static void
153 dingdong(int signo __unused)
154 {
155 	alarm(0);
156 	longjmp(timeout, 1);
157 }
158 
159 static jmp_buf	intrupt;
160 
161 static void
162 interrupt(int signo __unused)
163 {
164 	longjmp(intrupt, 1);
165 }
166 
167 /*
168  * Action to take when getty is running too long.
169  */
170 static void
171 timeoverrun(int signo __unused)
172 {
173 
174 	syslog(LOG_ERR, "getty exiting due to excessive running time");
175 	exit(1);
176 }
177 
178 int
179 main(int argc, char *argv[])
180 {
181 	int first_sleep = 1, first_time = 1;
182 	struct rlimit limit;
183 	int rval;
184 
185 	signal(SIGINT, SIG_IGN);
186 	signal(SIGQUIT, SIG_IGN);
187 
188 	openlog("getty", LOG_CONS|LOG_PID, LOG_AUTH);
189 	gethostname(hostname, sizeof(hostname) - 1);
190 	hostname[sizeof(hostname) - 1] = '\0';
191 	if (hostname[0] == '\0')
192 		snprintf(hostname, sizeof(hostname), "Amnesiac");
193 
194 	/*
195 	 * Limit running time to deal with broken or dead lines.
196 	 */
197 	(void)signal(SIGXCPU, timeoverrun);
198 	limit.rlim_max = RLIM_INFINITY;
199 	limit.rlim_cur = GETTY_TIMEOUT;
200 	(void)setrlimit(RLIMIT_CPU, &limit);
201 
202 	gettable("default");
203 	gendefaults();
204 	tname = "default";
205 	if (argc > 1)
206 		tname = argv[1];
207 
208 	/*
209 	 * The following is a work around for vhangup interactions
210 	 * which cause great problems getting window systems started.
211 	 * If the tty line is "-", we do the old style getty presuming
212 	 * that the file descriptors are already set up for us.
213 	 * J. Gettys - MIT Project Athena.
214 	 */
215 	if (argc <= 2 || strcmp(argv[2], "-") == 0) {
216 		char *n = ttyname(STDIN_FILENO);
217 		if (n == NULL) {
218 			syslog(LOG_ERR, "ttyname: %m");
219 			exit(1);
220 		}
221 		snprintf(ttyn, sizeof(ttyn), "%s", n);
222 	} else {
223 		snprintf(ttyn, sizeof(ttyn), "%s%s", _PATH_DEV, argv[2]);
224 		if (strcmp(argv[0], "+") != 0) {
225 			chown(ttyn, 0, 0);
226 			chmod(ttyn, 0600);
227 			revoke(ttyn);
228 
229 			/*
230 			 * Do the first scan through gettytab.
231 			 * Terminal mode parameters will be wrong until
232 			 * defttymode() called, but they're irrelevant for
233 			 * the initial setup of the terminal device.
234 			 */
235 			dogettytab();
236 
237 			/*
238 			 * Init or answer modem sequence has been specified.
239 			 */
240 			if (IC || AC) {
241 				if (!opentty(ttyn, O_RDWR|O_NONBLOCK))
242 					exit(1);
243 				defttymode();
244 				setttymode(1);
245 			}
246 
247 			if (IC) {
248 				if (getty_chat(IC, CT, DC) > 0) {
249 					syslog(LOG_ERR, "modem init problem on %s", ttyn);
250 					(void)tcsetattr(STDIN_FILENO, TCSANOW, &tmode);
251 					exit(1);
252 				}
253 			}
254 
255 			if (AC) {
256 				fd_set rfds;
257 				struct timeval to;
258 				int i;
259 
260 				FD_ZERO(&rfds);
261 				FD_SET(0, &rfds);
262 				to.tv_sec = RT;
263 				to.tv_usec = 0;
264 				i = select(32, &rfds, NULL, NULL, RT ? &to : NULL);
265 				if (i < 0) {
266 					syslog(LOG_ERR, "select %s: %m", ttyn);
267 				} else if (i == 0) {
268 					syslog(LOG_NOTICE, "recycle tty %s", ttyn);
269 					(void)tcsetattr(STDIN_FILENO, TCSANOW, &tmode);
270 					exit(0);  /* recycle for init */
271 				}
272 				i = getty_chat(AC, CT, DC);
273 				if (i > 0) {
274 					syslog(LOG_ERR, "modem answer problem on %s", ttyn);
275 					(void)tcsetattr(STDIN_FILENO, TCSANOW, &tmode);
276 					exit(1);
277 				}
278 			} else { /* maybe blocking open */
279 				if (!opentty(ttyn, O_RDWR | (NC ? O_NONBLOCK : 0 )))
280 					exit(1);
281 			}
282 		}
283 	}
284 
285 	defttymode();
286 	for (;;) {
287 
288 		/*
289 		 * if a delay was specified then sleep for that
290 		 * number of seconds before writing the initial prompt
291 		 */
292 		if (first_sleep && DE) {
293 			sleep(DE);
294 			/* remove any noise */
295 			(void)tcflush(STDIN_FILENO, TCIOFLUSH);
296 		}
297 		first_sleep = 0;
298 
299 		setttymode(0);
300 		if (AB) {
301 			tname = autobaud();
302 			dogettytab();
303 			continue;
304 		}
305 		if (PS) {
306 			tname = portselector();
307 			dogettytab();
308 			continue;
309 		}
310 		if (CL && *CL)
311 			putpad(CL);
312 		edithost(HE);
313 
314 		/* if this is the first time through this, and an
315 		   issue file has been given, then send it */
316 		if (first_time && IF) {
317 			int fd;
318 
319 			if ((fd = open(IF, O_RDONLY)) != -1) {
320 				char * cp;
321 
322 				while ((cp = get_line(fd)) != NULL) {
323 					putf(cp);
324 				}
325 				close(fd);
326 			}
327 		}
328 		first_time = 0;
329 
330 		if (IMP && *IMP && !(PL && PP))
331 			system(IMP);
332 		if (IM && *IM && !(PL && PP))
333 			putf(IM);
334 		if (setjmp(timeout)) {
335 			cfsetispeed(&tmode, B0);
336 			cfsetospeed(&tmode, B0);
337 			(void)tcsetattr(STDIN_FILENO, TCSANOW, &tmode);
338 			exit(1);
339 		}
340 		if (TO) {
341 			signal(SIGALRM, dingdong);
342 			alarm(TO);
343 		}
344 
345 		rval = 0;
346 		if (AL) {
347 			const char *p = AL;
348 			char *q = name;
349 
350 			while (*p && q < &name[sizeof name - 1]) {
351 				if (isupper(*p))
352 					upper = 1;
353 				else if (islower(*p))
354 					lower = 1;
355 				else if (isdigit(*p))
356 					digit = 1;
357 				*q++ = *p++;
358 			}
359 		} else if (!(PL && PP))
360 			rval = getname();
361 		if (rval == 2 || (PL && PP)) {
362 			oflush();
363 			alarm(0);
364 			limit.rlim_max = RLIM_INFINITY;
365 			limit.rlim_cur = RLIM_INFINITY;
366 			(void)setrlimit(RLIMIT_CPU, &limit);
367 			execle(PP, "ppplogin", ttyn, (char *) 0, env);
368 			syslog(LOG_ERR, "%s: %m", PP);
369 			exit(1);
370 		} else if (rval || AL) {
371 			int i;
372 
373 			oflush();
374 			alarm(0);
375 			signal(SIGALRM, SIG_DFL);
376 			if (name[0] == '\0')
377 				continue;
378 			if (name[0] == '-') {
379 				puts("user names may not start with '-'.");
380 				continue;
381 			}
382 			if (!(upper || lower || digit)) {
383 				if (AL) {
384 					syslog(LOG_ERR,
385 					    "invalid auto-login name: %s", AL);
386 					exit(1);
387 				} else
388 					continue;
389 			}
390 			set_flags(2);
391 			if (crmod) {
392 				tmode.c_iflag |= ICRNL;
393 				tmode.c_oflag |= ONLCR;
394 			}
395 #if REALLY_OLD_TTYS
396 			if (upper || UC)
397 				tmode.sg_flags |= LCASE;
398 			if (lower || LC)
399 				tmode.sg_flags &= ~LCASE;
400 #endif
401 			if (tcsetattr(STDIN_FILENO, TCSANOW, &tmode) < 0) {
402 				syslog(LOG_ERR, "tcsetattr %s: %m", ttyn);
403 				exit(1);
404 			}
405 			signal(SIGINT, SIG_DFL);
406 			for (i = 0; environ[i] != (char *)0; i++)
407 				env[i] = environ[i];
408 			makeenv(&env[i]);
409 
410 			limit.rlim_max = RLIM_INFINITY;
411 			limit.rlim_cur = RLIM_INFINITY;
412 			(void)setrlimit(RLIMIT_CPU, &limit);
413 			execle(LO, "login", AL ? "-fp" : "-p", name,
414 			    (char *) 0, env);
415 			syslog(LOG_ERR, "%s: %m", LO);
416 			exit(1);
417 		}
418 		alarm(0);
419 		signal(SIGALRM, SIG_DFL);
420 		signal(SIGINT, SIG_IGN);
421 		if (NX && *NX) {
422 			tname = NX;
423 			dogettytab();
424 		}
425 	}
426 }
427 
428 static int
429 opentty(const char *tty, int flags)
430 {
431 	int failopenlogged = 0, i, saved_errno;
432 
433 	while ((i = open(tty, flags)) == -1)
434 	{
435 		saved_errno = errno;
436 		if (!failopenlogged) {
437 			syslog(LOG_ERR, "open %s: %m", tty);
438 			failopenlogged = 1;
439 		}
440 		if (saved_errno == ENOENT)
441 			return 0;
442 		sleep(60);
443 	}
444 	if (login_tty(i) < 0) {
445 		if (daemon(0,0) < 0) {
446 			syslog(LOG_ERR,"daemon: %m");
447 			close(i);
448 			return 0;
449 		}
450 		if (login_tty(i) < 0) {
451 			syslog(LOG_ERR, "login_tty %s: %m", tty);
452 			close(i);
453 			return 0;
454 		}
455 	}
456 	return 1;
457 }
458 
459 static void
460 defttymode(void)
461 {
462 	struct termios def;
463 
464 	/* Start with default tty settings. */
465 	if (tcgetattr(STDIN_FILENO, &tmode) < 0) {
466 		syslog(LOG_ERR, "tcgetattr %s: %m", ttyn);
467 		exit(1);
468 	}
469 	omode = tmode; /* fill c_cc for dogettytab() */
470 	dogettytab();
471 	/*
472 	 * Don't rely on the driver too much, and initialize crucial
473 	 * things according to <sys/ttydefaults.h>.  Avoid clobbering
474 	 * the c_cc[] settings however, the console drivers might wish
475 	 * to leave their idea of the preferred VERASE key value
476 	 * there.
477 	 */
478 	cfmakesane(&def);
479 	tmode.c_iflag = def.c_iflag;
480 	tmode.c_oflag = def.c_oflag;
481 	tmode.c_lflag = def.c_lflag;
482 	tmode.c_cflag = def.c_cflag;
483 	if (NC)
484 		tmode.c_cflag |= CLOCAL;
485 	omode = tmode;
486 }
487 
488 static void
489 setttymode(int raw)
490 {
491 	int off = 0;
492 
493 	(void)tcflush(STDIN_FILENO, TCIOFLUSH);	/* clear out the crap */
494 	ioctl(STDIN_FILENO, FIONBIO, &off);	/* turn off non-blocking mode */
495 	ioctl(STDIN_FILENO, FIOASYNC, &off);	/* ditto for async mode */
496 
497 	if (IS)
498 		cfsetispeed(&tmode, speed(IS));
499 	else if (SP)
500 		cfsetispeed(&tmode, speed(SP));
501 	if (OS)
502 		cfsetospeed(&tmode, speed(OS));
503 	else if (SP)
504 		cfsetospeed(&tmode, speed(SP));
505 	set_flags(0);
506 	setchars();
507 	if (raw)
508 		cfmakeraw(&tmode);
509 	if (tcsetattr(STDIN_FILENO, TCSANOW, &tmode) < 0) {
510 		syslog(LOG_ERR, "tcsetattr %s: %m", ttyn);
511 		exit(1);
512 	}
513 }
514 
515 
516 static int
517 getname(void)
518 {
519 	int c;
520 	char *np;
521 	unsigned char cs;
522 	int ppp_state = 0;
523 	int ppp_connection = 0;
524 
525 	/*
526 	 * Interrupt may happen if we use CBREAK mode
527 	 */
528 	if (setjmp(intrupt)) {
529 		signal(SIGINT, SIG_IGN);
530 		return (0);
531 	}
532 	signal(SIGINT, interrupt);
533 	set_flags(1);
534 	prompt();
535 	oflush();
536 	if (PF > 0) {
537 		sleep(PF);
538 		PF = 0;
539 	}
540 	if (tcsetattr(STDIN_FILENO, TCSANOW, &tmode) < 0) {
541 		syslog(LOG_ERR, "%s: %m", ttyn);
542 		exit(1);
543 	}
544 	crmod = digit = lower = upper = 0;
545 	np = name;
546 	for (;;) {
547 		oflush();
548 		if (read(STDIN_FILENO, &cs, 1) <= 0)
549 			exit(0);
550 		if ((c = cs&0177) == 0)
551 			return (0);
552 
553 		/* PPP detection state machine..
554 		   Look for sequences:
555 		   PPP_FRAME, PPP_STATION, PPP_ESCAPE, PPP_CONTROL_ESCAPED or
556 		   PPP_FRAME, PPP_STATION, PPP_CONTROL (deviant from RFC)
557 		   See RFC1662.
558 		   Derived from code from Michael Hancock, <michaelh@cet.co.jp>
559 		   and Erik 'PPP' Olson, <eriko@wrq.com>
560 		*/
561 
562 		if (PP && (cs == PPP_FRAME)) {
563 			ppp_state = 1;
564 		} else if (ppp_state == 1 && cs == PPP_STATION) {
565 			ppp_state = 2;
566 		} else if (ppp_state == 2 && cs == PPP_ESCAPE) {
567 			ppp_state = 3;
568 		} else if ((ppp_state == 2 && cs == PPP_CONTROL)
569 		    || (ppp_state == 3 && cs == PPP_CONTROL_ESCAPED)) {
570 			ppp_state = 4;
571 		} else if (ppp_state == 4 && cs == PPP_LCP_HI) {
572 			ppp_state = 5;
573 		} else if (ppp_state == 5 && cs == PPP_LCP_LOW) {
574 			ppp_connection = 1;
575 			break;
576 		} else {
577 			ppp_state = 0;
578 		}
579 
580 		if (c == EOT || c == CTRL('d'))
581 			exit(0);
582 		if (c == '\r' || c == '\n' || np >= &name[sizeof name-1]) {
583 			putf("\r\n");
584 			break;
585 		}
586 		if (islower(c))
587 			lower = 1;
588 		else if (isupper(c))
589 			upper = 1;
590 		else if (c == ERASE || c == '\b' || c == 0177) {
591 			if (np > name) {
592 				np--;
593 				if (cfgetospeed(&tmode) >= 1200)
594 					puts("\b \b");
595 				else
596 					putchr(cs);
597 			}
598 			continue;
599 		} else if (c == KILL || c == CTRL('u')) {
600 			putchr('\r');
601 			if (cfgetospeed(&tmode) < 1200)
602 				putchr('\n');
603 			/* this is the way they do it down under ... */
604 			else if (np > name)
605 				puts("                                     \r");
606 			prompt();
607 			digit = lower = upper = 0;
608 			np = name;
609 			continue;
610 		} else if (isdigit(c))
611 			digit = 1;
612 		if (IG && (c <= ' ' || c > 0176))
613 			continue;
614 		*np++ = c;
615 		putchr(cs);
616 	}
617 	signal(SIGINT, SIG_IGN);
618 	*np = 0;
619 	if (c == '\r')
620 		crmod = 1;
621 	if ((upper && !lower && !LC) || UC)
622 		for (np = name; *np; np++)
623 			if (isupper(*np))
624 				*np = tolower(*np);
625 	return (1 + ppp_connection);
626 }
627 
628 static void
629 putpad(const char *s)
630 {
631 	int pad = 0;
632 	speed_t ospeed = cfgetospeed(&tmode);
633 
634 	if (isdigit(*s)) {
635 		while (isdigit(*s)) {
636 			pad *= 10;
637 			pad += *s++ - '0';
638 		}
639 		pad *= 10;
640 		if (*s == '.' && isdigit(s[1])) {
641 			pad += s[1] - '0';
642 			s += 2;
643 		}
644 	}
645 
646 	puts(s);
647 	/*
648 	 * If no delay needed, or output speed is
649 	 * not comprehensible, then don't try to delay.
650 	 */
651 	if (pad == 0 || ospeed <= 0)
652 		return;
653 
654 	/*
655 	 * Round up by a half a character frame, and then do the delay.
656 	 * Too bad there are no user program accessible programmed delays.
657 	 * Transmitting pad characters slows many terminals down and also
658 	 * loads the system.
659 	 */
660 	pad = (pad * ospeed + 50000) / 100000;
661 	while (pad--)
662 		putchr(*PC);
663 }
664 
665 static void
666 puts(const char *s)
667 {
668 	while (*s)
669 		putchr(*s++);
670 }
671 
672 static char	outbuf[OBUFSIZ];
673 static int	obufcnt = 0;
674 
675 static void
676 putchr(int cc)
677 {
678 	char c;
679 
680 	c = cc;
681 	if (!NP) {
682 		c |= partab[c&0177] & 0200;
683 		if (OP)
684 			c ^= 0200;
685 	}
686 	if (!UB) {
687 		outbuf[obufcnt++] = c;
688 		if (obufcnt >= OBUFSIZ)
689 			oflush();
690 	} else
691 		write(STDOUT_FILENO, &c, 1);
692 }
693 
694 static void
695 oflush(void)
696 {
697 	if (obufcnt)
698 		write(STDOUT_FILENO, outbuf, obufcnt);
699 	obufcnt = 0;
700 }
701 
702 static void
703 prompt(void)
704 {
705 
706 	putf(LM);
707 	if (CO)
708 		putchr('\n');
709 }
710 
711 
712 static char *
713 get_line(int fd)
714 {
715 	size_t i = 0;
716 	static char linebuf[512];
717 
718 	/*
719 	 * This is certainly slow, but it avoids having to include
720 	 * stdio.h unnecessarily. Issue files should be small anyway.
721 	 */
722 	while (i < (sizeof linebuf - 3) && read(fd, linebuf+i, 1)==1) {
723 		if (linebuf[i] == '\n') {
724 			/* Don't rely on newline mode, assume raw */
725 			linebuf[i++] = '\r';
726 			linebuf[i++] = '\n';
727 			linebuf[i] = '\0';
728 			return linebuf;
729 		}
730 		++i;
731 	}
732 	linebuf[i] = '\0';
733 	return i ? linebuf : 0;
734 }
735 
736 static void
737 putf(const char *cp)
738 {
739 	time_t t;
740 	char db[100];
741 	const char *slash;
742 
743 	static struct utsname kerninfo;
744 
745 	if (!*kerninfo.sysname)
746 		uname(&kerninfo);
747 
748 	while (*cp) {
749 		if (*cp != '%') {
750 			putchr(*cp++);
751 			continue;
752 		}
753 		switch (*++cp) {
754 
755 		case 't':
756 			slash = strrchr(ttyn, '/');
757 			if (slash == (char *) 0)
758 				puts(ttyn);
759 			else
760 				puts(&slash[1]);
761 			break;
762 
763 		case 'h':
764 			puts(editedhost);
765 			break;
766 
767 		case 'd':
768 			t = (time_t)0;
769 			(void)time(&t);
770 			if (Lo)
771 				(void)setlocale(LC_TIME, Lo);
772 			(void)strftime(db, sizeof(db), DF, localtime(&t));
773 			puts(db);
774 			break;
775 
776 		case 's':
777 			puts(kerninfo.sysname);
778 			break;
779 
780 		case 'm':
781 			puts(kerninfo.machine);
782 			break;
783 
784 		case 'r':
785 			puts(kerninfo.release);
786 			break;
787 
788 		case 'v':
789 			puts(kerninfo.version);
790 			break;
791 
792 		case '%':
793 			putchr('%');
794 			break;
795 		}
796 		cp++;
797 	}
798 }
799 
800 /*
801  * Read a gettytab database entry and perform necessary quirks.
802  */
803 static void
804 dogettytab(void)
805 {
806 
807 	/* Read the database entry. */
808 	gettable(tname);
809 
810 	/*
811 	 * Avoid inheriting the parity values from the default entry
812 	 * if any of them is set in the current entry.
813 	 * Mixing different parity settings is unreasonable.
814 	 */
815 	if (OPset || EPset || APset || NPset)
816 		OPset = EPset = APset = NPset = 1;
817 
818 	/* Fill in default values for unset capabilities. */
819 	setdefaults();
820 }
821