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 Mickiewicz <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#include "libbb.h"
19#include <syslog.h>
20
21#if ENABLE_FEATURE_UTMP
22# include <utmp.h> /* LOGIN_PROCESS */
23#endif
24
25#ifndef IUCLC
26# define IUCLC 0
27#endif
28
29/*
30 * Some heuristics to find out what environment we are in: if it is not
31 * System V, assume it is SunOS 4.
32 */
33#ifdef LOGIN_PROCESS                    /* defined in System V utmp.h */
34#include <sys/utsname.h>
35#else /* if !sysV style, wtmp/utmp code is off */
36#undef ENABLE_FEATURE_UTMP
37#undef ENABLE_FEATURE_WTMP
38#define ENABLE_FEATURE_UTMP 0
39#define ENABLE_FEATURE_WTMP 0
40#endif  /* LOGIN_PROCESS */
41
42/*
43 * Things you may want to modify.
44 *
45 * You may disagree with the default line-editing etc. characters defined
46 * below. Note, however, that DEL cannot be used for interrupt generation
47 * and for line editing at the same time.
48 */
49
50/* I doubt there are systems which still need this */
51#undef HANDLE_ALLCAPS
52#undef ANCIENT_BS_KILL_CHARS
53
54#define _PATH_LOGIN "/bin/login"
55
56/* If ISSUE is not defined, getty will never display the contents of the
57 * /etc/issue file. You will not want to spit out large "issue" files at the
58 * wrong baud rate.
59 */
60#define ISSUE "/etc/issue"              /* displayed before the login prompt */
61
62/* Some shorthands for control characters. */
63#define CTL(x)          ((x) ^ 0100)    /* Assumes ASCII dialect */
64#define CR              CTL('M')        /* carriage return */
65#define NL              CTL('J')        /* line feed */
66#define BS              CTL('H')        /* back space */
67#define DEL             CTL('?')        /* delete */
68
69/* Defaults for line-editing etc. characters; you may want to change this. */
70#define DEF_ERASE       DEL             /* default erase character */
71#define DEF_INTR        CTL('C')        /* default interrupt character */
72#define DEF_QUIT        CTL('\\')       /* default quit char */
73#define DEF_KILL        CTL('U')        /* default kill char */
74#define DEF_EOF         CTL('D')        /* default EOF char */
75#define DEF_EOL         '\n'
76#define DEF_SWITCH      0               /* default switch char */
77
78/*
79 * When multiple baud rates are specified on the command line, the first one
80 * we will try is the first one specified.
81 */
82#define MAX_SPEED       10              /* max. nr. of baud rates */
83
84/* Storage for command-line options. */
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
96/* Storage for things detected while the login name was read. */
97struct chardata {
98	unsigned char erase;    /* erase character */
99	unsigned char kill;     /* kill character */
100	unsigned char eol;      /* end-of-line character */
101	unsigned char parity;   /* what parity did we see */
102	/* (parity & 1): saw odd parity char with 7th bit set */
103	/* (parity & 2): saw even parity char with 7th bit set */
104	/* parity == 0: probably 7-bit, space parity? */
105	/* parity == 1: probably 7-bit, odd parity? */
106	/* parity == 2: probably 7-bit, even parity? */
107	/* parity == 3: definitely 8 bit, no parity! */
108	/* Hmm... with any value of "parity" 8 bit, no parity is possible */
109#ifdef HANDLE_ALLCAPS
110	unsigned char capslock; /* upper case without lower case */
111#endif
112};
113
114
115/* Initial values for the above. */
116static const struct chardata init_chardata = {
117	DEF_ERASE,                              /* default erase character */
118	DEF_KILL,                               /* default kill character */
119	13,                                     /* default eol char */
120	0,                                      /* space parity */
121#ifdef HANDLE_ALLCAPS
122	0,                                      /* no capslock */
123#endif
124};
125
126static const char opt_string[] ALIGN1 = "I:LH:f:hil:mt:wn";
127#define F_INITSTRING    (1 << 0)        /* -I initstring is set */
128#define F_LOCAL         (1 << 1)        /* -L force local */
129#define F_FAKEHOST      (1 << 2)        /* -H fake hostname */
130#define F_CUSTISSUE     (1 << 3)        /* -f give alternative issue file */
131#define F_RTSCTS        (1 << 4)        /* -h enable RTS/CTS flow control */
132#define F_ISSUE         (1 << 5)        /* -i display /etc/issue */
133#define F_LOGIN         (1 << 6)        /* -l non-default login program */
134#define F_PARSE         (1 << 7)        /* -m process modem status messages */
135#define F_TIMEOUT       (1 << 8)        /* -t time out */
136#define F_WAITCRLF      (1 << 9)        /* -w wait for CR or LF */
137#define F_NOPROMPT      (1 << 10)       /* -n don't ask for login name */
138
139
140#define line_buf bb_common_bufsiz1
141
142/* The following is used for understandable diagnostics. */
143#ifdef DEBUGGING
144static FILE *dbf;
145#define DEBUGTERM "/dev/ttyp0"
146#define debug(...) do { fprintf(dbf, __VA_ARGS__); fflush(dbf); } while (0)
147#else
148#define debug(...) ((void)0)
149#endif
150
151
152/* bcode - convert speed string to speed code; return <= 0 on failure */
153static int bcode(const char *s)
154{
155	int value = bb_strtou(s, NULL, 10); /* yes, int is intended! */
156	if (value < 0) /* bad terminating char, overflow, etc */
157		return value;
158	return tty_value_to_baud(value);
159}
160
161/* parse_speeds - parse alternate baud rates */
162static void parse_speeds(struct options *op, char *arg)
163{
164	char *cp;
165
166	/* NB: at least one iteration is always done */
167	debug("entered parse_speeds\n");
168	while ((cp = strsep(&arg, ",")) != NULL) {
169		op->speeds[op->numspeed] = bcode(cp);
170		if (op->speeds[op->numspeed] < 0)
171			bb_error_msg_and_die("bad speed: %s", cp);
172		/* note: arg "0" turns into speed B0 */
173		op->numspeed++;
174		if (op->numspeed > MAX_SPEED)
175			bb_error_msg_and_die("too many alternate speeds");
176	}
177	debug("exiting parse_speeds\n");
178}
179
180/* parse_args - parse command-line arguments */
181static void parse_args(char **argv, struct options *op, char **fakehost_p)
182{
183	char *ts;
184
185	opt_complementary = "-2:t+"; /* at least 2 args; -t N */
186	op->flags = getopt32(argv, opt_string,
187		&(op->initstring), fakehost_p, &(op->issue),
188		&(op->login), &op->timeout);
189	argv += optind;
190	if (op->flags & F_INITSTRING) {
191		const char *p = op->initstring;
192		char *q;
193
194		op->initstring = q = xstrdup(p);
195		/* copy optarg into op->initstring decoding \ddd
196		   octal codes into chars */
197		while (*p) {
198			if (*p == '\\') {
199				p++;
200				*q++ = bb_process_escape_sequence(&p);
201			} else {
202				*q++ = *p++;
203			}
204		}
205		*q = '\0';
206	}
207	op->flags ^= F_ISSUE;           /* invert flag "show /etc/issue" */
208	debug("after getopt\n");
209
210	/* we loosen up a bit and accept both "baudrate tty" and "tty baudrate" */
211	op->tty = argv[0];      /* tty name */
212	ts = argv[1];           /* baud rate(s) */
213	if (isdigit(argv[0][0])) {
214		/* a number first, assume it's a speed (BSD style) */
215		op->tty = ts;   /* tty name is in argv[1] */
216		ts = argv[0];   /* baud rate(s) */
217	}
218	parse_speeds(op, ts);
219
220// TODO: if applet_name is set to "getty: TTY", bb_error_msg's get simpler!
221// grep for "%s:"
222
223	if (argv[2])
224		xsetenv("TERM", argv[2]);
225
226	debug("exiting parse_args\n");
227}
228
229/* open_tty - set up tty as standard { input, output, error } */
230static void open_tty(const char *tty)
231{
232	/* Set up new standard input, unless we are given an already opened port. */
233	if (NOT_LONE_DASH(tty)) {
234//		struct stat st;
235//		int cur_dir_fd;
236//		int fd;
237
238		/* Sanity checks... */
239//		cur_dir_fd = xopen(".", O_DIRECTORY | O_NONBLOCK);
240//		xchdir("/dev");
241//		xstat(tty, &st);
242//		if (!S_ISCHR(st.st_mode))
243//			bb_error_msg_and_die("%s: not a character device", tty);
244
245		if (tty[0] != '/')
246			tty = xasprintf("/dev/%s", tty); /* will leak it */
247
248		/* Open the tty as standard input. */
249		debug("open(2)\n");
250		close(0);
251		/*fd =*/ xopen(tty, O_RDWR | O_NONBLOCK); /* uses fd 0 */
252
253//		/* Restore current directory */
254//		fchdir(cur_dir_fd);
255
256		/* Open the tty as standard input, continued */
257//		xmove_fd(fd, 0);
258//		/* fd is >= cur_dir_fd, and cur_dir_fd gets closed too here: */
259//		while (fd > 2)
260//			close(fd--);
261
262		/* Set proper protections and ownership. */
263		fchown(0, 0, 0);        /* 0:0 */
264		fchmod(0, 0620);        /* crw--w---- */
265	} else {
266		/*
267		 * Standard input should already be connected to an open port. Make
268		 * sure it is open for read/write.
269		 */
270		if ((fcntl(0, F_GETFL) & O_RDWR) != O_RDWR)
271			bb_error_msg_and_die("stdin is not open for read/write");
272	}
273}
274
275/* termios_init - initialize termios settings */
276static void termios_init(struct termios *tp, int speed, struct options *op)
277{
278	speed_t ispeed, ospeed;
279	/*
280	 * Initial termios settings: 8-bit characters, raw-mode, blocking i/o.
281	 * Special characters are set after we have read the login name; all
282	 * reads will be done in raw mode anyway. Errors will be dealt with
283	 * later on.
284	 */
285#ifdef __linux__
286	/* flush input and output queues, important for modems! */
287	ioctl(0, TCFLSH, TCIOFLUSH); /* tcflush(0, TCIOFLUSH)? - same */
288#endif
289	ispeed = ospeed = speed;
290	if (speed == B0) {
291		/* Speed was specified as "0" on command line.
292		 * Just leave it unchanged */
293		ispeed = cfgetispeed(tp);
294		ospeed = cfgetospeed(tp);
295	}
296	tp->c_cflag = CS8 | HUPCL | CREAD;
297	if (op->flags & F_LOCAL)
298		tp->c_cflag |= CLOCAL;
299	cfsetispeed(tp, ispeed);
300	cfsetospeed(tp, ospeed);
301
302	tp->c_iflag = tp->c_lflag = tp->c_line = 0;
303	tp->c_oflag = OPOST | ONLCR;
304	tp->c_cc[VMIN] = 1;
305	tp->c_cc[VTIME] = 0;
306
307	/* Optionally enable hardware flow control */
308#ifdef CRTSCTS
309	if (op->flags & F_RTSCTS)
310		tp->c_cflag |= CRTSCTS;
311#endif
312
313	tcsetattr_stdin_TCSANOW(tp);
314
315	debug("term_io 2\n");
316}
317
318/* auto_baud - extract baud rate from modem status message */
319static void auto_baud(char *buf, unsigned size_buf, struct termios *tp)
320{
321	int speed;
322	int vmin;
323	unsigned iflag;
324	char *bp;
325	int nread;
326
327	/*
328	 * This works only if the modem produces its status code AFTER raising
329	 * the DCD line, and if the computer is fast enough to set the proper
330	 * baud rate before the message has gone by. We expect a message of the
331	 * following format:
332	 *
333	 * <junk><number><junk>
334	 *
335	 * The number is interpreted as the baud rate of the incoming call. If the
336	 * modem does not tell us the baud rate within one second, we will keep
337	 * using the current baud rate. It is advisable to enable BREAK
338	 * processing (comma-separated list of baud rates) if the processing of
339	 * modem status messages is enabled.
340	 */
341
342	/*
343	 * Use 7-bit characters, don't block if input queue is empty. Errors will
344	 * be dealt with later on.
345	 */
346	iflag = tp->c_iflag;
347	tp->c_iflag |= ISTRIP;          /* enable 8th-bit stripping */
348	vmin = tp->c_cc[VMIN];
349	tp->c_cc[VMIN] = 0;             /* don't block if queue empty */
350	tcsetattr_stdin_TCSANOW(tp);
351
352	/*
353	 * Wait for a while, then read everything the modem has said so far and
354	 * try to extract the speed of the dial-in call.
355	 */
356	sleep(1);
357	nread = safe_read(STDIN_FILENO, buf, size_buf - 1);
358	if (nread > 0) {
359		buf[nread] = '\0';
360		for (bp = buf; bp < buf + nread; bp++) {
361			if (isdigit(*bp)) {
362				speed = bcode(bp);
363				if (speed > 0) {
364					tp->c_cflag &= ~CBAUD;
365					tp->c_cflag |= speed;
366				}
367				break;
368			}
369		}
370	}
371
372	/* Restore terminal settings. Errors will be dealt with later on. */
373	tp->c_iflag = iflag;
374	tp->c_cc[VMIN] = vmin;
375	tcsetattr_stdin_TCSANOW(tp);
376}
377
378/* do_prompt - show login prompt, optionally preceded by /etc/issue contents */
379static void do_prompt(struct options *op)
380{
381#ifdef ISSUE
382	print_login_issue(op->issue, op->tty);
383#endif
384	print_login_prompt();
385}
386
387#ifdef HANDLE_ALLCAPS
388/* all_is_upcase - string contains upper case without lower case */
389/* returns 1 if true, 0 if false */
390static int all_is_upcase(const char *s)
391{
392	while (*s)
393		if (islower(*s++))
394			return 0;
395	return 1;
396}
397#endif
398
399/* get_logname - get user name, establish parity, speed, erase, kill, eol;
400 * return NULL on BREAK, logname on success */
401static char *get_logname(char *logname, unsigned size_logname,
402		struct options *op, struct chardata *cp)
403{
404	char *bp;
405	char c;				/* input character, full eight bits */
406	char ascval;                    /* low 7 bits of input character */
407	int bits;                       /* # of "1" bits per character */
408	int mask;                       /* mask with 1 bit up */
409	static const char erase[][3] = {/* backspace-space-backspace */
410		"\010\040\010",                 /* space parity */
411		"\010\040\010",                 /* odd parity */
412		"\210\240\210",                 /* even parity */
413		"\010\040\010",                 /* 8 bit no parity */
414	};
415
416	/* NB: *cp is pre-initialized with init_chardata */
417
418	/* Flush pending input (esp. after parsing or switching the baud rate). */
419	sleep(1);
420	ioctl(0, TCFLSH, TCIFLUSH); /* tcflush(0, TCIOFLUSH)? - same */
421
422	/* Prompt for and read a login name. */
423	logname[0] = '\0';
424	while (!logname[0]) {
425		/* Write issue file and prompt, with "parity" bit == 0. */
426		do_prompt(op);
427
428		/* Read name, watch for break, parity, erase, kill, end-of-line. */
429		bp = logname;
430		cp->eol = '\0';
431		while (cp->eol == '\0') {
432
433			/* Do not report trivial EINTR/EIO errors. */
434			errno = EINTR; /* make read of 0 bytes be silent too */
435			if (read(STDIN_FILENO, &c, 1) < 1) {
436				if (errno == EINTR || errno == EIO)
437					exit(EXIT_SUCCESS);
438				bb_perror_msg_and_die("%s: read", op->tty);
439			}
440
441			/* BREAK. If we have speeds to try,
442			 * return NULL (will switch speeds and return here) */
443			if (c == '\0' && op->numspeed > 1)
444				return NULL;
445
446			/* Do parity bit handling. */
447			if (!(op->flags & F_LOCAL) && (c & 0x80)) {       /* "parity" bit on? */
448				bits = 1;
449				mask = 1;
450				while (mask & 0x7f) {
451					if (mask & c)
452						bits++; /* count "1" bits */
453					mask <<= 1;
454				}
455				/* ... |= 2 - even, 1 - odd */
456				cp->parity |= 2 - (bits & 1);
457			}
458
459			/* Do erase, kill and end-of-line processing. */
460			ascval = c & 0x7f;
461			switch (ascval) {
462			case CR:
463			case NL:
464				*bp = '\0';             /* terminate logname */
465				cp->eol = ascval;       /* set end-of-line char */
466				break;
467			case BS:
468			case DEL:
469#ifdef ANCIENT_BS_KILL_CHARS
470			case '#':
471#endif
472				cp->erase = ascval;     /* set erase character */
473				if (bp > logname) {
474					full_write(STDOUT_FILENO, erase[cp->parity], 3);
475					bp--;
476				}
477				break;
478			case CTL('U'):
479#ifdef ANCIENT_BS_KILL_CHARS
480			case '@':
481#endif
482				cp->kill = ascval;      /* set kill character */
483				while (bp > logname) {
484					full_write(STDOUT_FILENO, erase[cp->parity], 3);
485					bp--;
486				}
487				break;
488			case CTL('D'):
489				exit(EXIT_SUCCESS);
490			default:
491				if (ascval < ' ') {
492					/* ignore garbage characters */
493				} else if ((int)(bp - logname) >= size_logname - 1) {
494					bb_error_msg_and_die("%s: input overrun", op->tty);
495				} else {
496					full_write(STDOUT_FILENO, &c, 1); /* echo the character */
497					*bp++ = ascval; /* and store it */
498				}
499				break;
500			}
501		}
502	}
503	/* Handle names with upper case and no lower case. */
504
505#ifdef HANDLE_ALLCAPS
506	cp->capslock = all_is_upcase(logname);
507	if (cp->capslock) {
508		for (bp = logname; *bp; bp++)
509			if (isupper(*bp))
510				*bp = tolower(*bp);     /* map name to lower case */
511	}
512#endif
513	return logname;
514}
515
516/* termios_final - set the final tty mode bits */
517static void termios_final(struct options *op, struct termios *tp, struct chardata *cp)
518{
519	/* General terminal-independent stuff. */
520	tp->c_iflag |= IXON | IXOFF;    /* 2-way flow control */
521	tp->c_lflag |= ICANON | ISIG | ECHO | ECHOE | ECHOK | ECHOKE;
522	/* no longer| ECHOCTL | ECHOPRT */
523	tp->c_oflag |= OPOST;
524	/* tp->c_cflag = 0; */
525	tp->c_cc[VINTR] = DEF_INTR;     /* default interrupt */
526	tp->c_cc[VQUIT] = DEF_QUIT;     /* default quit */
527	tp->c_cc[VEOF] = DEF_EOF;       /* default EOF character */
528	tp->c_cc[VEOL] = DEF_EOL;
529	tp->c_cc[VSWTC] = DEF_SWITCH;   /* default switch character */
530
531	/* Account for special characters seen in input. */
532	if (cp->eol == CR) {
533		tp->c_iflag |= ICRNL;   /* map CR in input to NL */
534		tp->c_oflag |= ONLCR;   /* map NL in output to CR-NL */
535	}
536	tp->c_cc[VERASE] = cp->erase;   /* set erase character */
537	tp->c_cc[VKILL] = cp->kill;     /* set kill character */
538
539	/* Account for the presence or absence of parity bits in input. */
540	switch (cp->parity) {
541	case 0:                                 /* space (always 0) parity */
542// I bet most people go here - they use only 7-bit chars in usernames....
543		break;
544	case 1:                                 /* odd parity */
545		tp->c_cflag |= PARODD;
546		/* FALLTHROUGH */
547	case 2:                                 /* even parity */
548		tp->c_cflag |= PARENB;
549		tp->c_iflag |= INPCK | ISTRIP;
550		/* FALLTHROUGH */
551	case (1 | 2):                           /* no parity bit */
552		tp->c_cflag &= ~CSIZE;
553		tp->c_cflag |= CS7;
554// FIXME: wtf? case 3: we saw both even and odd 8-bit bytes -
555// it's probably some umlauts etc, but definitely NOT 7-bit!!!
556// Entire parity detection madness here just begs for deletion...
557		break;
558	}
559
560	/* Account for upper case without lower case. */
561#ifdef HANDLE_ALLCAPS
562	if (cp->capslock) {
563		tp->c_iflag |= IUCLC;
564		tp->c_lflag |= XCASE;
565		tp->c_oflag |= OLCUC;
566	}
567#endif
568	/* Optionally enable hardware flow control */
569#ifdef CRTSCTS
570	if (op->flags & F_RTSCTS)
571		tp->c_cflag |= CRTSCTS;
572#endif
573
574	/* Finally, make the new settings effective */
575	/* It's tcsetattr_stdin_TCSANOW() + error check */
576	ioctl_or_perror_and_die(0, TCSETS, tp, "%s: TCSETS", op->tty);
577}
578
579int getty_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
580int getty_main(int argc UNUSED_PARAM, char **argv)
581{
582	int n;
583	pid_t pid;
584	char *fakehost = NULL;          /* Fake hostname for ut_host */
585	char *logname;                  /* login name, given to /bin/login */
586	/* Merging these into "struct local" may _seem_ to reduce
587	 * parameter passing, but today's gcc will inline
588	 * statics which are called once anyway, so don't do that */
589	struct chardata chardata;       /* set by get_logname() */
590	struct termios termios;         /* terminal mode bits */
591	struct options options;
592
593	chardata = init_chardata;
594
595	memset(&options, 0, sizeof(options));
596	options.login =	_PATH_LOGIN;    /* default login program */
597	options.tty = "tty1";           /* default tty line */
598	options.initstring = "";        /* modem init string */
599#ifdef ISSUE
600	options.issue = ISSUE;          /* default issue file */
601#endif
602
603	/* Parse command-line arguments. */
604	parse_args(argv, &options, &fakehost);
605
606	logmode = LOGMODE_NONE;
607
608	/* Create new session, lose controlling tty, if any */
609	/* docs/ctty.htm says:
610	 * "This is allowed only when the current process
611	 *  is not a process group leader" - is this a problem? */
612	setsid();
613	/* close stdio, and stray descriptors, just in case */
614	n = xopen(bb_dev_null, O_RDWR);
615	/* dup2(n, 0); - no, we need to handle "getty - 9600" too */
616	xdup2(n, 1);
617	xdup2(n, 2);
618	while (n > 2)
619		close(n--);
620
621	/* Logging. We want special flavor of error_msg_and_die */
622	die_sleep = 10;
623	msg_eol = "\r\n";
624	/* most likely will internally use fd #3 in CLOEXEC mode: */
625	openlog(applet_name, LOG_PID, LOG_AUTH);
626	logmode = LOGMODE_BOTH;
627
628#ifdef DEBUGGING
629	dbf = xfopen_for_write(DEBUGTERM);
630	for (n = 1; argv[n]; n++) {
631		debug(argv[n]);
632		debug("\n");
633	}
634#endif
635
636	/* Open the tty as standard input, if it is not "-" */
637	/* If it's not "-" and not taken yet, it will become our ctty */
638	debug("calling open_tty\n");
639	open_tty(options.tty);
640	ndelay_off(0);
641	debug("duping\n");
642	xdup2(0, 1);
643	xdup2(0, 2);
644
645	/*
646	 * The following ioctl will fail if stdin is not a tty, but also when
647	 * there is noise on the modem control lines. In the latter case, the
648	 * common course of action is (1) fix your cables (2) give the modem more
649	 * time to properly reset after hanging up. SunOS users can achieve (2)
650	 * by patching the SunOS kernel variable "zsadtrlow" to a larger value;
651	 * 5 seconds seems to be a good value.
652	 */
653	/* tcgetattr() + error check */
654	ioctl_or_perror_and_die(0, TCGETS, &termios, "%s: TCGETS", options.tty);
655
656	pid = getpid();
657#ifdef __linux__
658// FIXME: do we need this? Otherwise "-" case seems to be broken...
659	// /* Forcibly make fd 0 our controlling tty, even if another session
660	//  * has it as a ctty. (Another session loses ctty). */
661	// ioctl(0, TIOCSCTTY, (void*)1);
662	/* Make ourself a foreground process group within our session */
663	tcsetpgrp(0, pid);
664#endif
665
666	/* Update the utmp file. This tty is ours now! */
667	update_utmp(pid, LOGIN_PROCESS, options.tty, "LOGIN", fakehost);
668
669	/* Initialize the termios settings (raw mode, eight-bit, blocking i/o). */
670	debug("calling termios_init\n");
671	termios_init(&termios, options.speeds[0], &options);
672
673	/* Write the modem init string and DON'T flush the buffers */
674	if (options.flags & F_INITSTRING) {
675		debug("writing init string\n");
676		full_write1_str(options.initstring);
677	}
678
679	/* Optionally detect the baud rate from the modem status message */
680	debug("before autobaud\n");
681	if (options.flags & F_PARSE)
682		auto_baud(line_buf, sizeof(line_buf), &termios);
683
684	/* Set the optional timer */
685	alarm(options.timeout); /* if 0, alarm is not set */
686
687	/* Optionally wait for CR or LF before writing /etc/issue */
688	if (options.flags & F_WAITCRLF) {
689		char ch;
690
691		debug("waiting for cr-lf\n");
692		while (safe_read(STDIN_FILENO, &ch, 1) == 1) {
693			debug("read %x\n", (unsigned char)ch);
694			ch &= 0x7f;                     /* strip "parity bit" */
695			if (ch == '\n' || ch == '\r')
696				break;
697		}
698	}
699
700	logname = NULL;
701	if (!(options.flags & F_NOPROMPT)) {
702		/* NB:termios_init already set line speed
703		 * to options.speeds[0] */
704		int baud_index = 0;
705
706		while (1) {
707			/* Read the login name. */
708			debug("reading login name\n");
709			logname = get_logname(line_buf, sizeof(line_buf),
710					&options, &chardata);
711			if (logname)
712				break;
713			/* we are here only if options.numspeed > 1 */
714			baud_index = (baud_index + 1) % options.numspeed;
715			cfsetispeed(&termios, options.speeds[baud_index]);
716			cfsetospeed(&termios, options.speeds[baud_index]);
717			tcsetattr_stdin_TCSANOW(&termios);
718		}
719	}
720
721	/* Disable timer. */
722	alarm(0);
723
724	/* Finalize the termios settings. */
725	termios_final(&options, &termios, &chardata);
726
727	/* Now the newline character should be properly written. */
728	full_write(STDOUT_FILENO, "\n", 1);
729
730	/* Let the login program take care of password validation. */
731	/* We use PATH because we trust that root doesn't set "bad" PATH,
732	 * and getty is not suid-root applet. */
733	/* With -n, logname == NULL, and login will ask for username instead */
734	BB_EXECLP(options.login, options.login, "--", logname, NULL);
735	bb_error_msg_and_die("%s: can't exec %s", options.tty, options.login);
736}
737