1/* vi: set sw=4 ts=4: */
2/* agetty.c - another getty program for Linux. By W. Z. Venema 1989
3 * Ported to Linux by Peter Orbaek <poe@daimi.aau.dk>
4 * This program is freely distributable. The entire man-page used to
5 * be here. Now read the real man-page agetty.8 instead.
6 *
7 * option added by Eric Rasmussen <ear@usfirst.org> - 12/28/95
8 *
9 * 1999-02-22 Arkadiusz Mi�kiewicz <misiek@misiek.eu.org>
10 * - added Native Language Support
11
12 * 1999-05-05 Thorsten Kranzkowski <dl8bcu@gmx.net>
13 * - enable hardware flow control before displaying /etc/issue
14 *
15 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
16 *
17 */
18
19#include "libbb.h"
20#include <syslog.h>
21
22#if ENABLE_FEATURE_UTMP
23#include <utmp.h>
24#endif
25
26/*
27 * Some heuristics to find out what environment we are in: if it is not
28 * System V, assume it is SunOS 4.
29 */
30#ifdef LOGIN_PROCESS                        /* defined in System V utmp.h */
31#define SYSV_STYLE                      /* select System V style getty */
32#include <sys/utsname.h>
33#include <time.h>
34#if ENABLE_FEATURE_WTMP
35extern void updwtmp(const char *filename, const struct utmp *ut);
36static void update_utmp(const char *line);
37#endif
38#endif  /* LOGIN_PROCESS */
39
40/*
41 * Things you may want to modify.
42 *
43 * You may disagree with the default line-editing etc. characters defined
44 * below. Note, however, that DEL cannot be used for interrupt generation
45 * and for line editing at the same time.
46 */
47
48/* I doubt there are systems which still need this */
49#undef HANDLE_ALLCAPS
50
51#define _PATH_LOGIN "/bin/login"
52
53/* If ISSUE is not defined, getty will never display the contents of the
54 * /etc/issue file. You will not want to spit out large "issue" files at the
55 * wrong baud rate.
56 */
57#define ISSUE "/etc/issue"              /* displayed before the login prompt */
58
59/* Some shorthands for control characters. */
60#define CTL(x)          (x ^ 0100)      /* Assumes ASCII dialect */
61#define CR              CTL('M')        /* carriage return */
62#define NL              CTL('J')        /* line feed */
63#define BS              CTL('H')        /* back space */
64#define DEL             CTL('?')        /* delete */
65
66/* Defaults for line-editing etc. characters; you may want to change this. */
67#define DEF_ERASE       DEL             /* default erase character */
68#define DEF_INTR        CTL('C')        /* default interrupt character */
69#define DEF_QUIT        CTL('\\')       /* default quit char */
70#define DEF_KILL        CTL('U')        /* default kill char */
71#define DEF_EOF         CTL('D')        /* default EOF char */
72#define DEF_EOL         '\n'
73#define DEF_SWITCH      0               /* default switch char */
74
75/*
76 * When multiple baud rates are specified on the command line, the first one
77 * we will try is the first one specified.
78 */
79#define FIRST_SPEED     0
80
81/* Storage for command-line options. */
82
83#define MAX_SPEED       10              /* max. nr. of baud rates */
84
85struct options {
86	int flags;                      /* toggle switches, see below */
87	unsigned timeout;               /* time-out period */
88	const char *login;                    /* login program */
89	const char *tty;                      /* name of tty */
90	const char *initstring;               /* modem init string */
91	const char *issue;                    /* alternative issue file */
92	int numspeed;                   /* number of baud rates to try */
93	int speeds[MAX_SPEED];          /* baud rates to be tried */
94};
95
96static const char opt_string[] ALIGN1 = "I:LH:f:hil:mt:wn";
97#define F_INITSTRING    (1<<0)          /* initstring is set */
98#define F_LOCAL         (1<<1)          /* force local */
99#define F_FAKEHOST      (1<<2)          /* force fakehost */
100#define F_CUSTISSUE     (1<<3)          /* give alternative issue file */
101#define F_RTSCTS        (1<<4)          /* enable RTS/CTS flow control */
102#define F_ISSUE         (1<<5)          /* display /etc/issue */
103#define F_LOGIN         (1<<6)          /* non-default login program */
104#define F_PARSE         (1<<7)          /* process modem status messages */
105#define F_TIMEOUT       (1<<8)          /* time out */
106#define F_WAITCRLF      (1<<9)          /* wait for CR or LF */
107#define F_NOPROMPT      (1<<10)         /* don't ask for login name! */
108
109/* Storage for things detected while the login name was read. */
110struct chardata {
111	unsigned char erase;    /* erase character */
112	unsigned char kill;     /* kill character */
113	unsigned char eol;      /* end-of-line character */
114	unsigned char parity;   /* what parity did we see */
115#ifdef HANDLE_ALLCAPS
116	unsigned char capslock; /* upper case without lower case */
117#endif
118};
119
120/* Initial values for the above. */
121static const struct chardata init_chardata = {
122	DEF_ERASE,                              /* default erase character */
123	DEF_KILL,                               /* default kill character */
124	13,                                     /* default eol char */
125	0,                                      /* space parity */
126#ifdef HANDLE_ALLCAPS
127	0,                                      /* no capslock */
128#endif
129};
130
131/* The following is used for understandable diagnostics. */
132
133/* Fake hostname for ut_host specified on command line. */
134static char *fakehost = NULL;
135
136/* ... */
137#ifdef DEBUGGING
138#define debug(s) fprintf(dbf,s); fflush(dbf)
139#define DEBUGTERM "/dev/ttyp0"
140static FILE *dbf;
141#else
142#define debug(s) /* nothing */
143#endif
144
145
146/* bcode - convert speed string to speed code; return 0 on failure */
147static int bcode(const char *s)
148{
149	int r;
150	unsigned value = bb_strtou(s, NULL, 10);
151	if (errno) {
152		return -1;
153	}
154	r = tty_value_to_baud(value);
155	if (r > 0) {
156		return r;
157	}
158	return 0;
159}
160
161
162/* parse_speeds - parse alternate baud rates */
163static void parse_speeds(struct options *op, char *arg)
164{
165	char *cp;
166
167	debug("entered parse_speeds\n");
168	for (cp = strtok(arg, ","); cp != 0; cp = strtok((char *) 0, ",")) {
169		if ((op->speeds[op->numspeed++] = bcode(cp)) <= 0)
170			bb_error_msg_and_die("bad speed: %s", cp);
171		if (op->numspeed > MAX_SPEED)
172			bb_error_msg_and_die("too many alternate speeds");
173	}
174	debug("exiting parsespeeds\n");
175}
176
177
178/* parse_args - parse command-line arguments */
179static void parse_args(int argc, char **argv, struct options *op)
180{
181	char *ts;
182
183	op->flags = getopt32(argv, opt_string,
184		&(op->initstring), &fakehost, &(op->issue),
185		&(op->login), &ts);
186	if (op->flags & F_INITSTRING) {
187		const char *p = op->initstring;
188		char *q;
189
190		op->initstring = q = xstrdup(op->initstring);
191		/* copy optarg into op->initstring decoding \ddd
192		   octal codes into chars */
193		while (*p) {
194			if (*p == '\\') {
195				p++;
196				*q++ = bb_process_escape_sequence(&p);
197			} else {
198				*q++ = *p++;
199			}
200		}
201		*q = '\0';
202	}
203	op->flags ^= F_ISSUE;           /* revert flag show /etc/issue */
204	if (op->flags & F_TIMEOUT) {
205		op->timeout = xatoul_range(ts, 1, INT_MAX);
206	}
207	argv += optind;
208	argc -= optind;
209	debug("after getopt loop\n");
210	if (argc < 2)          /* check parameter count */
211		bb_show_usage();
212
213	/* we loosen up a bit and accept both "baudrate tty" and "tty baudrate" */
214	if (isdigit(argv[0][0])) {
215		/* a number first, assume it's a speed (BSD style) */
216		parse_speeds(op, argv[0]);       /* baud rate(s) */
217		op->tty = argv[1]; /* tty name */
218	} else {
219		op->tty = argv[0];       /* tty name */
220		parse_speeds(op, argv[1]); /* baud rate(s) */
221	}
222
223	if (argv[2])
224		setenv("TERM", argv[2], 1);
225
226	debug("exiting parseargs\n");
227}
228
229/* open_tty - set up tty as standard { input, output, error } */
230static void open_tty(const char *tty, struct termios *tp, int local)
231{
232	int chdir_to_root = 0;
233
234	/* Set up new standard input, unless we are given an already opened port. */
235	if (NOT_LONE_DASH(tty)) {
236		struct stat st;
237		int fd;
238
239		/* Sanity checks... */
240		xchdir("/dev");
241		chdir_to_root = 1;
242		xstat(tty, &st);
243		if ((st.st_mode & S_IFMT) != S_IFCHR)
244			bb_error_msg_and_die("%s: not a character device", tty);
245
246		/* Open the tty as standard input. */
247		debug("open(2)\n");
248		fd = xopen(tty, O_RDWR | O_NONBLOCK);
249		xdup2(fd, 0);
250		while (fd > 2)
251			close(fd--);
252	} else {
253		/*
254		 * Standard input should already be connected to an open port. Make
255		 * sure it is open for read/write.
256		 */
257		if ((fcntl(0, F_GETFL) & O_RDWR) != O_RDWR)
258			bb_error_msg_and_die("stdin is not open for read/write");
259	}
260
261	/* Replace current standard output/error fd's with new ones */
262	debug("duping\n");
263	xdup2(0, 1);
264	xdup2(0, 2);
265
266	/*
267	 * The following ioctl will fail if stdin is not a tty, but also when
268	 * there is noise on the modem control lines. In the latter case, the
269	 * common course of action is (1) fix your cables (2) give the modem more
270	 * time to properly reset after hanging up. SunOS users can achieve (2)
271	 * by patching the SunOS kernel variable "zsadtrlow" to a larger value;
272	 * 5 seconds seems to be a good value.
273	 */
274	ioctl_or_perror_and_die(0, TCGETS, tp, "%s: TCGETS", tty);
275
276	/*
277	 * It seems to be a terminal. Set proper protections and ownership. Mode
278	 * 0622 is suitable for SYSV <4 because /bin/login does not change
279	 * protections. SunOS 4 login will change the protections to 0620 (write
280	 * access for group tty) after the login has succeeded.
281	 */
282
283#ifdef DEBIAN
284#warning Debian /dev/vcs[a]NN hack is deprecated and will be removed
285	{
286		/* tty to root.dialout 660 */
287		struct group *gr;
288		int id;
289
290		gr = getgrnam("dialout");
291		id = gr ? gr->gr_gid : 0;
292		chown(tty, 0, id);
293		chmod(tty, 0660);
294
295		/* vcs,vcsa to root.sys 600 */
296		if (!strncmp(tty, "tty", 3) && isdigit(tty[3])) {
297			char *vcs, *vcsa;
298
299			vcs = xstrdup(tty);
300			vcsa = xmalloc(strlen(tty) + 2);
301			strcpy(vcs, "vcs");
302			strcpy(vcs + 3, tty + 3);
303			strcpy(vcsa, "vcsa");
304			strcpy(vcsa + 4, tty + 3);
305
306			gr = getgrnam("sys");
307			id = gr ? gr->gr_gid : 0;
308			chown(vcs, 0, id);
309			chmod(vcs, 0600);
310			chown(vcsa, 0, id);
311			chmod(vcs, 0600);
312
313			free(vcs);
314			free(vcsa);
315		}
316	}
317#else
318	if (NOT_LONE_DASH(tty)) {
319		chown(tty, 0, 0);        /* 0:0 */
320		chmod(tty, 0622);        /* crw--w--w- */
321	}
322#endif
323	if (chdir_to_root)
324		xchdir("/");
325}
326
327/* termios_init - initialize termios settings */
328static void termios_init(struct termios *tp, int speed, struct options *op)
329{
330	/*
331	 * Initial termios settings: 8-bit characters, raw-mode, blocking i/o.
332	 * Special characters are set after we have read the login name; all
333	 * reads will be done in raw mode anyway. Errors will be dealt with
334	 * later on.
335	 */
336#ifdef __linux__
337	/* flush input and output queues, important for modems! */
338	ioctl(0, TCFLSH, TCIOFLUSH);
339#endif
340
341	tp->c_cflag = CS8 | HUPCL | CREAD | speed;
342	if (op->flags & F_LOCAL) {
343		tp->c_cflag |= CLOCAL;
344	}
345
346	tp->c_iflag = tp->c_lflag = tp->c_line = 0;
347	tp->c_oflag = OPOST | ONLCR;
348	tp->c_cc[VMIN] = 1;
349	tp->c_cc[VTIME] = 0;
350
351	/* Optionally enable hardware flow control */
352
353#ifdef  CRTSCTS
354	if (op->flags & F_RTSCTS)
355		tp->c_cflag |= CRTSCTS;
356#endif
357
358	ioctl(0, TCSETS, tp);
359
360	/* go to blocking input even in local mode */
361	ndelay_off(0);
362
363	debug("term_io 2\n");
364}
365
366/* auto_baud - extract baud rate from modem status message */
367static void auto_baud(char *buf, unsigned size_buf, struct termios *tp)
368{
369	int speed;
370	int vmin;
371	unsigned iflag;
372	char *bp;
373	int nread;
374
375	/*
376	 * This works only if the modem produces its status code AFTER raising
377	 * the DCD line, and if the computer is fast enough to set the proper
378	 * baud rate before the message has gone by. We expect a message of the
379	 * following format:
380	 *
381	 * <junk><number><junk>
382	 *
383	 * The number is interpreted as the baud rate of the incoming call. If the
384	 * modem does not tell us the baud rate within one second, we will keep
385	 * using the current baud rate. It is advisable to enable BREAK
386	 * processing (comma-separated list of baud rates) if the processing of
387	 * modem status messages is enabled.
388	 */
389
390	/*
391	 * Use 7-bit characters, don't block if input queue is empty. Errors will
392	 * be dealt with later on.
393	 */
394
395	iflag = tp->c_iflag;
396	tp->c_iflag |= ISTRIP;          /* enable 8th-bit stripping */
397	vmin = tp->c_cc[VMIN];
398	tp->c_cc[VMIN] = 0;                     /* don't block if queue empty */
399	ioctl(0, TCSETS, tp);
400
401	/*
402	 * Wait for a while, then read everything the modem has said so far and
403	 * try to extract the speed of the dial-in call.
404	 */
405
406	sleep(1);
407	nread = read(0, buf, size_buf - 1);
408	if (nread > 0) {
409		buf[nread] = '\0';
410		for (bp = buf; bp < buf + nread; bp++) {
411			if (isascii(*bp) && isdigit(*bp)) {
412				speed = bcode(bp);
413				if (speed) {
414					tp->c_cflag &= ~CBAUD;
415					tp->c_cflag |= speed;
416				}
417				break;
418			}
419		}
420	}
421	/* Restore terminal settings. Errors will be dealt with later on. */
422
423	tp->c_iflag = iflag;
424	tp->c_cc[VMIN] = vmin;
425	ioctl(0, TCSETS, tp);
426}
427
428/* next_speed - select next baud rate */
429static void next_speed(struct termios *tp, struct options *op)
430{
431	static int baud_index = FIRST_SPEED;    /* current speed index */
432
433	baud_index = (baud_index + 1) % op->numspeed;
434	tp->c_cflag &= ~CBAUD;
435	tp->c_cflag |= op->speeds[baud_index];
436	ioctl(0, TCSETS, tp);
437}
438
439
440/* do_prompt - show login prompt, optionally preceded by /etc/issue contents */
441static void do_prompt(struct options *op, struct termios *tp)
442{
443#ifdef ISSUE
444	print_login_issue(op->issue, op->tty);
445#endif
446	print_login_prompt();
447}
448
449#ifdef HANDLE_ALLCAPS
450/* caps_lock - string contains upper case without lower case */
451/* returns 1 if true, 0 if false */
452static int caps_lock(const char *s)
453{
454	while (*s)
455		if (islower(*s++))
456			return 0;
457	return 1;
458}
459#endif
460
461/* get_logname - get user name, establish parity, speed, erase, kill, eol */
462/* return NULL on failure, logname on success */
463static char *get_logname(char *logname, unsigned size_logname,
464		struct options *op, struct chardata *cp, struct termios *tp)
465{
466	char *bp;
467	char c;				/* input character, full eight bits */
468	char ascval;                    /* low 7 bits of input character */
469	int bits;                       /* # of "1" bits per character */
470	int mask;                       /* mask with 1 bit up */
471	static const char erase[][3] = {    /* backspace-space-backspace */
472		"\010\040\010",                 /* space parity */
473		"\010\040\010",                 /* odd parity */
474		"\210\240\210",                 /* even parity */
475		"\210\240\210",                 /* no parity */
476	};
477
478	/* Initialize kill, erase, parity etc. (also after switching speeds). */
479
480	*cp = init_chardata;
481
482	/* Flush pending input (esp. after parsing or switching the baud rate). */
483
484	sleep(1);
485	ioctl(0, TCFLSH, TCIFLUSH);
486
487	/* Prompt for and read a login name. */
488
489	logname[0] = '\0';
490	while (!logname[0]) {
491
492		/* Write issue file and prompt, with "parity" bit == 0. */
493
494		do_prompt(op, tp);
495
496		/* Read name, watch for break, parity, erase, kill, end-of-line. */
497
498		bp = logname;
499		cp->eol = '\0';
500		while (cp->eol == '\0') {
501
502			/* Do not report trivial EINTR/EIO errors. */
503			if (read(0, &c, 1) < 1) {
504				if (errno == EINTR || errno == EIO)
505					exit(0);
506				bb_perror_msg_and_die("%s: read", op->tty);
507			}
508
509			/* Do BREAK handling elsewhere. */
510			if (c == '\0' && op->numspeed > 1)
511				return NULL;
512
513			/* Do parity bit handling. */
514			ascval = c & 0177;
515			if (c != ascval) {       /* "parity" bit on ? */
516				bits = 1;
517				mask = 1;
518				while (mask & 0177) {
519					if (mask & ascval)
520						bits++; /* count "1" bits */
521					mask <<= 1;
522				}
523				/* ... |= 2 - even, 1 - odd */
524				cp->parity |= 2 - (bits & 1);
525			}
526
527			/* Do erase, kill and end-of-line processing. */
528			switch (ascval) {
529			case CR:
530			case NL:
531				*bp = '\0';             /* terminate logname */
532				cp->eol = ascval;       /* set end-of-line char */
533				break;
534			case BS:
535			case DEL:
536			case '#':
537				cp->erase = ascval;     /* set erase character */
538				if (bp > logname) {
539					write(1, erase[cp->parity], 3);
540					bp--;
541				}
542				break;
543			case CTL('U'):
544			case '@':
545				cp->kill = ascval;      /* set kill character */
546				while (bp > logname) {
547					write(1, erase[cp->parity], 3);
548					bp--;
549				}
550				break;
551			case CTL('D'):
552				exit(0);
553			default:
554				if (!isascii(ascval) || !isprint(ascval)) {
555					/* ignore garbage characters */
556				} else if (bp - logname >= size_logname - 1) {
557					bb_error_msg_and_die("%s: input overrun", op->tty);
558				} else {
559					write(1, &c, 1); /* echo the character */
560					*bp++ = ascval; /* and store it */
561				}
562				break;
563			}
564		}
565	}
566	/* Handle names with upper case and no lower case. */
567
568#ifdef HANDLE_ALLCAPS
569	cp->capslock = caps_lock(logname);
570	if (cp->capslock) {
571		for (bp = logname; *bp; bp++)
572			if (isupper(*bp))
573				*bp = tolower(*bp);     /* map name to lower case */
574	}
575#endif
576	return logname;
577}
578
579/* termios_final - set the final tty mode bits */
580static void termios_final(struct options *op, struct termios *tp, struct chardata *cp)
581{
582	/* General terminal-independent stuff. */
583
584	tp->c_iflag |= IXON | IXOFF;    /* 2-way flow control */
585	tp->c_lflag |= ICANON | ISIG | ECHO | ECHOE | ECHOK | ECHOKE;
586	/* no longer| ECHOCTL | ECHOPRT */
587	tp->c_oflag |= OPOST;
588	/* tp->c_cflag = 0; */
589	tp->c_cc[VINTR] = DEF_INTR;     /* default interrupt */
590	tp->c_cc[VQUIT] = DEF_QUIT;     /* default quit */
591	tp->c_cc[VEOF] = DEF_EOF;       /* default EOF character */
592	tp->c_cc[VEOL] = DEF_EOL;
593	tp->c_cc[VSWTC] = DEF_SWITCH;   /* default switch character */
594
595	/* Account for special characters seen in input. */
596
597	if (cp->eol == CR) {
598		tp->c_iflag |= ICRNL;   /* map CR in input to NL */
599		tp->c_oflag |= ONLCR;   /* map NL in output to CR-NL */
600	}
601	tp->c_cc[VERASE] = cp->erase;   /* set erase character */
602	tp->c_cc[VKILL] = cp->kill;     /* set kill character */
603
604	/* Account for the presence or absence of parity bits in input. */
605
606	switch (cp->parity) {
607	case 0:                                 /* space (always 0) parity */
608		break;
609	case 1:                                 /* odd parity */
610		tp->c_cflag |= PARODD;
611		/* FALLTHROUGH */
612	case 2:                                 /* even parity */
613		tp->c_cflag |= PARENB;
614		tp->c_iflag |= INPCK | ISTRIP;
615		/* FALLTHROUGH */
616	case (1 | 2):                           /* no parity bit */
617		tp->c_cflag &= ~CSIZE;
618		tp->c_cflag |= CS7;
619		break;
620	}
621
622	/* Account for upper case without lower case. */
623#ifdef HANDLE_ALLCAPS
624	if (cp->capslock) {
625		tp->c_iflag |= IUCLC;
626		tp->c_lflag |= XCASE;
627		tp->c_oflag |= OLCUC;
628	}
629#endif
630	/* Optionally enable hardware flow control */
631
632#ifdef  CRTSCTS
633	if (op->flags & F_RTSCTS)
634		tp->c_cflag |= CRTSCTS;
635#endif
636
637	/* Finally, make the new settings effective */
638
639	ioctl_or_perror_and_die(0, TCSETS, tp, "%s: TCSETS", op->tty);
640}
641
642
643#ifdef SYSV_STYLE
644#if ENABLE_FEATURE_UTMP
645/* update_utmp - update our utmp entry */
646static void update_utmp(const char *line)
647{
648	struct utmp ut;
649	struct utmp *utp;
650	time_t t;
651	int mypid = getpid();
652
653	/*
654	 * The utmp file holds miscellaneous information about things started by
655	 * /sbin/init and other system-related events. Our purpose is to update
656	 * the utmp entry for the current process, in particular the process type
657	 * and the tty line we are listening to. Return successfully only if the
658	 * utmp file can be opened for update, and if we are able to find our
659	 * entry in the utmp file.
660	 */
661	if (access(_PATH_UTMP, R_OK|W_OK) == -1) {
662		close(creat(_PATH_UTMP, 0664));
663	}
664	utmpname(_PATH_UTMP);
665	setutent();
666	while ((utp = getutent())
667		   && !(utp->ut_type == INIT_PROCESS && utp->ut_pid == mypid))
668		/* nothing */;
669
670	if (utp) {
671		memcpy(&ut, utp, sizeof(ut));
672	} else {
673		/* some inits don't initialize utmp... */
674		memset(&ut, 0, sizeof(ut));
675		safe_strncpy(ut.ut_id, line + 3, sizeof(ut.ut_id));
676	}
677	/* endutent(); */
678
679	strcpy(ut.ut_user, "LOGIN");
680	safe_strncpy(ut.ut_line, line, sizeof(ut.ut_line));
681	if (fakehost)
682		safe_strncpy(ut.ut_host, fakehost, sizeof(ut.ut_host));
683	time(&t);
684	ut.ut_time = t;
685	ut.ut_type = LOGIN_PROCESS;
686	ut.ut_pid = mypid;
687
688	pututline(&ut);
689	endutent();
690
691#if ENABLE_FEATURE_WTMP
692	if (access(bb_path_wtmp_file, R_OK|W_OK) == -1)
693		close(creat(bb_path_wtmp_file, 0664));
694	updwtmp(bb_path_wtmp_file, &ut);
695#endif
696}
697
698#endif /* CONFIG_FEATURE_UTMP */
699#endif /* SYSV_STYLE */
700
701
702int getty_main(int argc, char **argv);
703int getty_main(int argc, char **argv)
704{
705	int nullfd;
706	char *logname = NULL;           /* login name, given to /bin/login */
707	/* Merging these into "struct local" may _seem_ to reduce
708	 * parameter passing, but today's gcc will inline
709	 * statics which are called once anyway, so don't do that */
710	struct chardata chardata;       /* set by get_logname() */
711	struct termios termios;           /* terminal mode bits */
712	struct options options = {
713		0,                      /* show /etc/issue (SYSV_STYLE) */
714		0,                      /* no timeout */
715		_PATH_LOGIN,            /* default login program */
716		"tty1",                 /* default tty line */
717		"",                     /* modem init string */
718#ifdef ISSUE
719		ISSUE,                  /* default issue file */
720#else
721		NULL,
722#endif
723		0,                      /* no baud rates known yet */
724	};
725
726	/* Already too late because of theoretical
727	 * possibility of getty --help somehow triggered
728	 * inadvertently before we reach this. Oh well. */
729	logmode = LOGMODE_NONE;
730	setsid();
731	nullfd = xopen(bb_dev_null, O_RDWR);
732	/* dup2(nullfd, 0); - no, because of possible "getty - 9600" */
733	/* open_tty() will take care of fd# 0 anyway */
734	dup2(nullfd, 1);
735	dup2(nullfd, 2);
736	while (nullfd > 2) close(nullfd--);
737	/* We want special flavor of error_msg_and_die */
738	die_sleep = 10;
739	msg_eol = "\r\n";
740	openlog(applet_name, LOG_PID, LOG_AUTH);
741	logmode = LOGMODE_BOTH;
742
743#ifdef DEBUGGING
744	dbf = xfopen(DEBUGTERM, "w");
745
746	{
747		int i;
748
749		for (i = 1; i < argc; i++) {
750			debug(argv[i]);
751			debug("\n");
752		}
753	}
754#endif
755
756	/* Parse command-line arguments. */
757	parse_args(argc, argv, &options);
758
759#ifdef SYSV_STYLE
760#if ENABLE_FEATURE_UTMP
761	/* Update the utmp file. */
762	update_utmp(options.tty);
763#endif
764#endif
765
766	debug("calling open_tty\n");
767	/* Open the tty as standard { input, output, error }. */
768	open_tty(options.tty, &termios, options.flags & F_LOCAL);
769
770#ifdef __linux__
771	{
772		int iv;
773
774		iv = getpid();
775		ioctl(0, TIOCSPGRP, &iv);
776	}
777#endif
778	/* Initialize the termios settings (raw mode, eight-bit, blocking i/o). */
779	debug("calling termios_init\n");
780	termios_init(&termios, options.speeds[FIRST_SPEED], &options);
781
782	/* write the modem init string and DON'T flush the buffers */
783	if (options.flags & F_INITSTRING) {
784		debug("writing init string\n");
785		write(1, options.initstring, strlen(options.initstring));
786	}
787
788	if (!(options.flags & F_LOCAL)) {
789		/* go to blocking write mode unless -L is specified */
790		ndelay_off(1);
791	}
792
793	/* Optionally detect the baud rate from the modem status message. */
794	debug("before autobaud\n");
795	if (options.flags & F_PARSE)
796		auto_baud(bb_common_bufsiz1, sizeof(bb_common_bufsiz1), &termios);
797
798	/* Set the optional timer. */
799	if (options.timeout)
800		alarm(options.timeout);
801
802	/* optionally wait for CR or LF before writing /etc/issue */
803	if (options.flags & F_WAITCRLF) {
804		char ch;
805
806		debug("waiting for cr-lf\n");
807		while (read(0, &ch, 1) == 1) {
808			ch &= 0x7f;                     /* strip "parity bit" */
809#ifdef DEBUGGING
810			fprintf(dbf, "read %c\n", ch);
811#endif
812			if (ch == '\n' || ch == '\r')
813				break;
814		}
815	}
816
817	chardata = init_chardata;
818	if (!(options.flags & F_NOPROMPT)) {
819		/* Read the login name. */
820		debug("reading login name\n");
821		logname = get_logname(bb_common_bufsiz1, sizeof(bb_common_bufsiz1),
822				&options, &chardata, &termios);
823		while (logname == NULL)
824			next_speed(&termios, &options);
825	}
826
827	/* Disable timer. */
828
829	if (options.timeout)
830		alarm(0);
831
832	/* Finalize the termios settings. */
833
834	termios_final(&options, &termios, &chardata);
835
836	/* Now the newline character should be properly written. */
837
838	write(1, "\n", 1);
839
840	/* Let the login program take care of password validation. */
841
842	execl(options.login, options.login, "--", logname, (char *) 0);
843	bb_error_msg_and_die("%s: can't exec %s", options.tty, options.login);
844}
845