aboutsummaryrefslogtreecommitdiff
path: root/loginutils/getty.c
blob: 22601c74e4f898a2cde169eed4184b0fb7a28c3e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
/* vi: set sw=4 ts=4: */
/* agetty.c - another getty program for Linux. By W. Z. Venema 1989
 * Ported to Linux by Peter Orbaek <poe@daimi.aau.dk>
 * This program is freely distributable. The entire man-page used to
 * be here. Now read the real man-page agetty.8 instead.
 *
 * option added by Eric Rasmussen <ear@usfirst.org> - 12/28/95
 *
 * 1999-02-22 Arkadiusz Mi∂kiewicz <misiek@misiek.eu.org>
 * - added Native Language Support

 * 1999-05-05 Thorsten Kranzkowski <dl8bcu@gmx.net>
 * - enable hardware flow control before displaying /etc/issue
 *
 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
 *
 */

#include "busybox.h"
#include <syslog.h>

#ifdef CONFIG_FEATURE_UTMP
#include <utmp.h>
#endif

#define _PATH_LOGIN     "/bin/login"

#ifdef CONFIG_SYSLOGD
#include <sys/param.h>
#endif


 /*
  * Some heuristics to find out what environment we are in: if it is not
  * System V, assume it is SunOS 4.
  */

#ifdef LOGIN_PROCESS                    /* defined in System V utmp.h */
#define SYSV_STYLE                      /* select System V style getty */
#ifdef CONFIG_FEATURE_WTMP
extern void updwtmp(const char *filename, const struct utmp *ut);
#endif
#endif  /* LOGIN_PROCESS */

 /*
  * Things you may want to modify.
  *
  * You may disagree with the default line-editing etc. characters defined
  * below. Note, however, that DEL cannot be used for interrupt generation
  * and for line editing at the same time.
  */

#ifdef  SYSV_STYLE
#include <sys/utsname.h>
#include <time.h>
#endif

 /* If ISSUE is not defined, agetty will never display the contents of the
  * /etc/issue file. You will not want to spit out large "issue" files at the
  * wrong baud rate.
  */
#define ISSUE "/etc/issue"              /* displayed before the login prompt */

/* Some shorthands for control characters. */

#define CTL(x)          (x ^ 0100)      /* Assumes ASCII dialect */
#define CR              CTL('M')        /* carriage return */
#define NL              CTL('J')        /* line feed */
#define BS              CTL('H')        /* back space */
#define DEL             CTL('?')        /* delete */

/* Defaults for line-editing etc. characters; you may want to change this. */

#define DEF_ERASE       DEL             /* default erase character */
#define DEF_INTR        CTL('C')        /* default interrupt character */
#define DEF_QUIT        CTL('\\')       /* default quit char */
#define DEF_KILL        CTL('U')        /* default kill char */
#define DEF_EOF         CTL('D')        /* default EOF char */
#define DEF_EOL         '\n'
#define DEF_SWITCH      0               /* default switch char */

 /*
  * SunOS 4.1.1 termio is broken. We must use the termios stuff instead,
  * because the termio -> termios translation does not clear the termios
  * CIBAUD bits. Therefore, the tty driver would sometimes report that input
  * baud rate != output baud rate. I did not notice that problem with SunOS
  * 4.1. We will use termios where available, and termio otherwise.
  */

/* linux 0.12 termio is broken too, if we use it c_cc[VERASE] isn't set
   properly, but all is well if we use termios?! */

#ifdef  TCGETS
#undef  TCGETA
#undef  TCSETA
#undef  TCSETAW
#define termio  termios
#define TCGETA  TCGETS
#define TCSETA  TCSETS
#define TCSETAW TCSETSW
#endif

 /*
  * When multiple baud rates are specified on the command line, the first one
  * we will try is the first one specified.
  */

#define FIRST_SPEED     0

/* Storage for command-line options. */

#define MAX_SPEED       10              /* max. nr. of baud rates */

struct options {
	int flags;                      /* toggle switches, see below */
	int timeout;                    /* time-out period */
	char *login;                    /* login program */
	char *tty;                      /* name of tty */
	char *initstring;               /* modem init string */
	char *issue;                    /* alternative issue file */
	int numspeed;                   /* number of baud rates to try */
	int speeds[MAX_SPEED];          /* baud rates to be tried */
};

static const char opt_string[] = "I:LH:f:hil:mt:wn";
#define F_INITSTRING    (1<<0)          /* initstring is set */
#define F_LOCAL         (1<<1)          /* force local */
#define F_FAKEHOST      (1<<2)          /* force fakehost */
#define F_CUSTISSUE     (1<<3)          /* give alternative issue file */
#define F_RTSCTS        (1<<4)          /* enable RTS/CTS flow control */
#define F_ISSUE         (1<<5)          /* display /etc/issue */
#define F_LOGIN         (1<<6)          /* non-default login program */
#define F_PARSE         (1<<7)          /* process modem status messages */
#define F_TIMEOUT       (1<<8)          /* time out */
#define F_WAITCRLF      (1<<9)          /* wait for CR or LF */
#define F_NOPROMPT      (1<<10)         /* don't ask for login name! */

/* Storage for things detected while the login name was read. */

struct chardata {
	int erase;                      /* erase character */
	int kill;                       /* kill character */
	int eol;                        /* end-of-line character */
	int parity;                     /* what parity did we see */
	int capslock;                   /* upper case without lower case */
};

/* Initial values for the above. */

static struct chardata init_chardata = {
	DEF_ERASE,                              /* default erase character */
	DEF_KILL,                               /* default kill character */
	13,                                     /* default eol char */
	0,                                      /* space parity */
	0,                                      /* no capslock */
};

#if 0
struct Speedtab {
	long speed;
	int code;
};

static struct Speedtab speedtab[] = {
	{50, B50},
	{75, B75},
	{110, B110},
	{134, B134},
	{150, B150},
	{200, B200},
	{300, B300},
	{600, B600},
	{1200, B1200},
	{1800, B1800},
	{2400, B2400},
	{4800, B4800},
	{9600, B9600},
#ifdef  B19200
	{19200, B19200},
#endif
#ifdef  B38400
	{38400, B38400},
#endif
#ifdef  EXTA
	{19200, EXTA},
#endif
#ifdef  EXTB
	{38400, EXTB},
#endif
#ifdef B57600
	{57600, B57600},
#endif
#ifdef B115200
	{115200, B115200},
#endif
#ifdef B230400
	{230400, B230400},
#endif
	{0, 0},
};
#endif


#ifdef  SYSV_STYLE
#ifdef CONFIG_FEATURE_UTMP
static void update_utmp(char *line);
#endif
#endif

/* The following is used for understandable diagnostics. */

/* Fake hostname for ut_host specified on command line. */
static char *fakehost = NULL;

/* ... */
#ifdef DEBUGGING
#define debug(s) fprintf(dbf,s); fflush(dbf)
#define DEBUGTERM "/dev/ttyp0"
FILE *dbf;
#else
#define debug(s)                                /* nothing */
#endif


/* bcode - convert speed string to speed code; return 0 on failure */
static int bcode(const char *s)
{
	int r;
	unsigned long value;
	if (safe_strtoul((char *)s, &value)) {
		return -1;
	}
	if ((r = tty_value_to_baud(value)) > 0) {
		return r;
	}
	return 0;
}


/* parse_speeds - parse alternate baud rates */
static void parse_speeds(struct options *op, char *arg)
{
	char *cp;

	debug("entered parse_speeds\n");
	for (cp = strtok(arg, ","); cp != 0; cp = strtok((char *) 0, ",")) {
		if ((op->speeds[op->numspeed++] = bcode(cp)) <= 0)
			bb_error_msg_and_die("bad speed: %s", cp);
		if (op->numspeed > MAX_SPEED)
			bb_error_msg_and_die("too many alternate speeds");
	}
	debug("exiting parsespeeds\n");
}


/* parse_args - parse command-line arguments */
static void parse_args(int argc, char **argv, struct options *op)
{
	char *ts;

	op->flags = bb_getopt_ulflags(argc, argv, opt_string,
		&(op->initstring), &fakehost, &(op->issue),
		&(op->login), &ts);
	if(op->flags & F_INITSTRING) {
		const char *p = op->initstring;
		char *q;

		q = op->initstring = xstrdup(op->initstring);
		/* copy optarg into op->initstring decoding \ddd
		   octal codes into chars */
		while (*p) {
			if (*p == '\\') {
				p++;
				*q++ = bb_process_escape_sequence(&p);
			} else {
				*q++ = *p++;
			}
		}
		*q = '\0';
	}
	op->flags ^= F_ISSUE;           /* revert flag show /etc/issue */
	if(op->flags & F_TIMEOUT) {
		if ((op->timeout = atoi(ts)) <= 0)
			bb_error_msg_and_die("bad timeout value: %s", ts);
	}
	debug("after getopt loop\n");
	if (argc < optind + 2)          /* check parameter count */
		bb_show_usage();

	/* we loosen up a bit and accept both "baudrate tty" and "tty baudrate" */
	if ('0' <= argv[optind][0] && argv[optind][0] <= '9') {
		/* a number first, assume it's a speed (BSD style) */
		parse_speeds(op, argv[optind++]);       /* baud rate(s) */
		op->tty = argv[optind]; /* tty name */
	} else {
		op->tty = argv[optind++];       /* tty name */
		parse_speeds(op, argv[optind]); /* baud rate(s) */
	}

	optind++;
	if (argc > optind && argv[optind])
		setenv("TERM", argv[optind], 1);

	debug("exiting parseargs\n");
}

static void xdup2(int srcfd, int dstfd, const char *tty)
{
	if(dup2(srcfd, dstfd) == -1)
		bb_perror_msg_and_die("%s: dup", tty);
}

/* open_tty - set up tty as standard { input, output, error } */
static void open_tty(char *tty, struct termio *tp, int local)
{
	int chdir_to_root = 0;

	/* Set up new standard input, unless we are given an already opened port. */

	if (strcmp(tty, "-")) {
		struct stat st;
		int fd;

		/* Sanity checks... */

		xchdir("/dev");
		chdir_to_root = 1;
		xstat(tty, &st);
		if ((st.st_mode & S_IFMT) != S_IFCHR)
			bb_error_msg_and_die("%s: not a character device", tty);

		/* Open the tty as standard input. */

		debug("open(2)\n");
		fd = xopen(tty, O_RDWR | O_NONBLOCK);
		if(fd) {
			xdup2(fd, 0, tty);
			close(fd);
		}
	} else {
		/*
		 * Standard input should already be connected to an open port. Make
		 * sure it is open for read/write.
		 */

		if ((fcntl(0, F_GETFL, 0) & O_RDWR) != O_RDWR)
			bb_error_msg_and_die("%s: not open for read/write", tty);
	}

	/* Replace current standard output/error fd's with new ones */
	debug("duping\n");
	xdup2(0, 1, tty);
	xdup2(0, 2, tty);

	/*
	 * The following ioctl will fail if stdin is not a tty, but also when
	 * there is noise on the modem control lines. In the latter case, the
	 * common course of action is (1) fix your cables (2) give the modem more
	 * time to properly reset after hanging up. SunOS users can achieve (2)
	 * by patching the SunOS kernel variable "zsadtrlow" to a larger value;
	 * 5 seconds seems to be a good value.
	 */

	if (ioctl(0, TCGETA, tp) < 0)
		bb_perror_msg_and_die("%s: ioctl(TCGETA)", tty);

	/*
	 * It seems to be a terminal. Set proper protections and ownership. Mode
	 * 0622 is suitable for SYSV <4 because /bin/login does not change
	 * protections. SunOS 4 login will change the protections to 0620 (write
	 * access for group tty) after the login has succeeded.
	 */

#ifdef DEBIAN
	{
		/* tty to root.dialout 660 */
		struct group *gr;
		int id;

		id = (gr = getgrnam("dialout")) ? gr->gr_gid : 0;
		chown(tty, 0, id);
		chmod(tty, 0660);

		/* vcs,vcsa to root.sys 600 */
		if (!strncmp(tty, "tty", 3) && isdigit(tty[3])) {
			char *vcs, *vcsa;

			vcs = xstrdup(tty);
			vcsa = xmalloc(strlen(tty) + 2);
			strcpy(vcs, "vcs");
			strcpy(vcs + 3, tty + 3);
			strcpy(vcsa, "vcsa");
			strcpy(vcsa + 4, tty + 3);

			id = (gr = getgrnam("sys")) ? gr->gr_gid : 0;
			chown(vcs, 0, id);
			chmod(vcs, 0600);
			chown(vcsa, 0, id);
			chmod(vcs, 0600);

			free(vcs);
			free(vcsa);
		}
	}
#else
	(void) chown(tty, 0, 0);        /* root, sys */
	(void) chmod(tty, 0622);        /* crw--w--w- */
#endif
	if (chdir_to_root)
		xchdir("/");
}

/* termio_init - initialize termio settings */
static void termio_init(struct termio *tp, int speed, struct options *op)
{
	/*
	 * Initial termio settings: 8-bit characters, raw-mode, blocking i/o.
	 * Special characters are set after we have read the login name; all
	 * reads will be done in raw mode anyway. Errors will be dealt with
	 * lateron.
	 */
#ifdef __linux__
	/* flush input and output queues, important for modems! */
	(void) ioctl(0, TCFLSH, TCIOFLUSH);
#endif

	tp->c_cflag = CS8 | HUPCL | CREAD | speed;
	if (op->flags & F_LOCAL) {
		tp->c_cflag |= CLOCAL;
	}

	tp->c_iflag = tp->c_lflag = tp->c_line = 0;
	tp->c_oflag = OPOST | ONLCR;
	tp->c_cc[VMIN] = 1;
	tp->c_cc[VTIME] = 0;

	/* Optionally enable hardware flow control */

#ifdef  CRTSCTS
	if (op->flags & F_RTSCTS)
		tp->c_cflag |= CRTSCTS;
#endif

	(void) ioctl(0, TCSETA, tp);

	/* go to blocking input even in local mode */
	fcntl(0, F_SETFL, fcntl(0, F_GETFL, 0) & ~O_NONBLOCK);

	debug("term_io 2\n");
}

/* auto_baud - extract baud rate from modem status message */
static void auto_baud(struct termio *tp)
{
	int speed;
	int vmin;
	unsigned iflag;
	char buf[BUFSIZ];
	char *bp;
	int nread;

	/*
	 * This works only if the modem produces its status code AFTER raising
	 * the DCD line, and if the computer is fast enough to set the proper
	 * baud rate before the message has gone by. We expect a message of the
	 * following format:
	 *
	 * <junk><number><junk>
	 *
	 * The number is interpreted as the baud rate of the incoming call. If the
	 * modem does not tell us the baud rate within one second, we will keep
	 * using the current baud rate. It is advisable to enable BREAK
	 * processing (comma-separated list of baud rates) if the processing of
	 * modem status messages is enabled.
	 */

	/*
	 * Use 7-bit characters, don't block if input queue is empty. Errors will
	 * be dealt with lateron.
	 */

	iflag = tp->c_iflag;
	tp->c_iflag |= ISTRIP;          /* enable 8th-bit stripping */
	vmin = tp->c_cc[VMIN];
	tp->c_cc[VMIN] = 0;                     /* don't block if queue empty */
	(void) ioctl(0, TCSETA, tp);

	/*
	 * Wait for a while, then read everything the modem has said so far and
	 * try to extract the speed of the dial-in call.
	 */

	(void) sleep(1);
	if ((nread = read(0, buf, sizeof(buf) - 1)) > 0) {
		buf[nread] = '\0';
		for (bp = buf; bp < buf + nread; bp++) {
			if (isascii(*bp) && isdigit(*bp)) {
				if ((speed = bcode(bp))) {
					tp->c_cflag &= ~CBAUD;
					tp->c_cflag |= speed;
				}
				break;
			}
		}
	}
	/* Restore terminal settings. Errors will be dealt with lateron. */

	tp->c_iflag = iflag;
	tp->c_cc[VMIN] = vmin;
	(void) ioctl(0, TCSETA, tp);
}

/* next_speed - select next baud rate */
static void next_speed(struct termio *tp, struct options *op)
{
	static int baud_index = FIRST_SPEED;    /* current speed index */

	baud_index = (baud_index + 1) % op->numspeed;
	tp->c_cflag &= ~CBAUD;
	tp->c_cflag |= op->speeds[baud_index];
	(void) ioctl(0, TCSETA, tp);
}


/* do_prompt - show login prompt, optionally preceded by /etc/issue contents */
static void do_prompt(struct options *op, struct termio *tp)
{
#ifdef  ISSUE                                   /* optional: show /etc/issue */
	print_login_issue(op->issue, op->tty);
#endif
	print_login_prompt();
}

/* caps_lock - string contains upper case without lower case */
/* returns 1 if true, 0 if false */
static int caps_lock(const char *s)
{
	int capslock;

	for (capslock = 0; *s; s++) {
		if (islower(*s))
			return (0);
		if (capslock == 0)
			capslock = isupper(*s);
	}
	return (capslock);
}

#define logname bb_common_bufsiz1
/* get_logname - get user name, establish parity, speed, erase, kill, eol */
/* return NULL on failure, logname on success */
static char *get_logname(struct options *op, struct chardata *cp, struct termio *tp)
{
	char *bp;
	char c;				/* input character, full eight bits */
	char ascval;                    /* low 7 bits of input character */
	int bits;                       /* # of "1" bits per character */
	int mask;                       /* mask with 1 bit up */
	static char *erase[] = {        /* backspace-space-backspace */
		"\010\040\010",                 /* space parity */
		"\010\040\010",                 /* odd parity */
		"\210\240\210",                 /* even parity */
		"\210\240\210",                 /* no parity */
	};

	/* Initialize kill, erase, parity etc. (also after switching speeds). */

	*cp = init_chardata;

	/* Flush pending input (esp. after parsing or switching the baud rate). */

	(void) sleep(1);
	(void) ioctl(0, TCFLSH, TCIFLUSH);

	/* Prompt for and read a login name. */

	for (*logname = 0; *logname == 0; /* void */ ) {

		/* Write issue file and prompt, with "parity" bit == 0. */

		do_prompt(op, tp);

		/* Read name, watch for break, parity, erase, kill, end-of-line. */

		for (bp = logname, cp->eol = 0; cp->eol == 0; /* void */ ) {

			/* Do not report trivial EINTR/EIO errors. */

			if (read(0, &c, 1) < 1) {
				if (errno == EINTR || errno == EIO)
					exit(0);
				bb_perror_msg_and_die("%s: read", op->tty);
			}
			/* Do BREAK handling elsewhere. */

			if ((c == 0) && op->numspeed > 1)
				/* return (0); */
				return NULL;

			/* Do parity bit handling. */

			if (c != (ascval = (c & 0177))) {       /* "parity" bit on ? */
				for (bits = 1, mask = 1; mask & 0177; mask <<= 1)
					if (mask & ascval)
						bits++; /* count "1" bits */
				cp->parity |= ((bits & 1) ? 1 : 2);
			}
			/* Do erase, kill and end-of-line processing. */

			switch (ascval) {
			case CR:
			case NL:
				*bp = 0;                /* terminate logname */
				cp->eol = ascval;       /* set end-of-line char */
				break;
			case BS:
			case DEL:
			case '#':
				cp->erase = ascval;     /* set erase character */
				if (bp > logname) {
					(void) write(1, erase[cp->parity], 3);
					bp--;
				}
				break;
			case CTL('U'):
			case '@':
				cp->kill = ascval;      /* set kill character */
				while (bp > logname) {
					(void) write(1, erase[cp->parity], 3);
					bp--;
				}
				break;
			case CTL('D'):
				exit(0);
			default:
				if (!isascii(ascval) || !isprint(ascval)) {
					/* ignore garbage characters */ ;
				} else if (bp - logname >= sizeof(logname) - 1) {
					bb_error_msg_and_die("%s: input overrun", op->tty);
				} else {
					(void) write(1, &c, 1); /* echo the character */
					*bp++ = ascval; /* and store it */
				}
				break;
			}
		}
	}
	/* Handle names with upper case and no lower case. */

	if ((cp->capslock = caps_lock(logname))) {
		for (bp = logname; *bp; bp++)
			if (isupper(*bp))
				*bp = tolower(*bp);     /* map name to lower case */
	}
	return (logname);
}

/* termio_final - set the final tty mode bits */
static void termio_final(struct options *op, struct termio *tp, struct chardata *cp)
{
	/* General terminal-independent stuff. */

	tp->c_iflag |= IXON | IXOFF;    /* 2-way flow control */
	tp->c_lflag |= ICANON | ISIG | ECHO | ECHOE | ECHOK | ECHOKE;
	/* no longer| ECHOCTL | ECHOPRT */
	tp->c_oflag |= OPOST;
	/* tp->c_cflag = 0; */
	tp->c_cc[VINTR] = DEF_INTR;     /* default interrupt */
	tp->c_cc[VQUIT] = DEF_QUIT;     /* default quit */
	tp->c_cc[VEOF] = DEF_EOF;       /* default EOF character */
	tp->c_cc[VEOL] = DEF_EOL;
	tp->c_cc[VSWTC] = DEF_SWITCH;   /* default switch character */

	/* Account for special characters seen in input. */

	if (cp->eol == CR) {
		tp->c_iflag |= ICRNL;   /* map CR in input to NL */
		tp->c_oflag |= ONLCR;   /* map NL in output to CR-NL */
	}
	tp->c_cc[VERASE] = cp->erase;   /* set erase character */
	tp->c_cc[VKILL] = cp->kill;     /* set kill character */

	/* Account for the presence or absence of parity bits in input. */

	switch (cp->parity) {
	case 0:                                 /* space (always 0) parity */
		break;
	case 1:                                 /* odd parity */
		tp->c_cflag |= PARODD;
		/* FALLTHROUGH */
	case 2:                                 /* even parity */
		tp->c_cflag |= PARENB;
		tp->c_iflag |= INPCK | ISTRIP;
		/* FALLTHROUGH */
	case (1 | 2):                           /* no parity bit */
		tp->c_cflag &= ~CSIZE;
		tp->c_cflag |= CS7;
		break;
	}
	/* Account for upper case without lower case. */

	if (cp->capslock) {
		tp->c_iflag |= IUCLC;
		tp->c_lflag |= XCASE;
		tp->c_oflag |= OLCUC;
	}
	/* Optionally enable hardware flow control */

#ifdef  CRTSCTS
	if (op->flags & F_RTSCTS)
		tp->c_cflag |= CRTSCTS;
#endif

	/* Finally, make the new settings effective */

	if (ioctl(0, TCSETA, tp) < 0)
		bb_perror_msg_and_die("%s: ioctl(TCSETA)", op->tty);
}


#ifdef  SYSV_STYLE
#ifdef CONFIG_FEATURE_UTMP
/* update_utmp - update our utmp entry */
static void update_utmp(char *line)
{
	struct utmp ut;
	struct utmp *utp;
	time_t t;
	int mypid = getpid();
#if ! (__GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 1))
	struct flock lock;
#endif

	/*
	 * The utmp file holds miscellaneous information about things started by
	 * /sbin/init and other system-related events. Our purpose is to update
	 * the utmp entry for the current process, in particular the process type
	 * and the tty line we are listening to. Return successfully only if the
	 * utmp file can be opened for update, and if we are able to find our
	 * entry in the utmp file.
	 */
	if (access(_PATH_UTMP, R_OK|W_OK) == -1) {
		close(creat(_PATH_UTMP, 0664));
	}
	utmpname(_PATH_UTMP);
	setutent();
	while ((utp = getutent())
		   && !(utp->ut_type == INIT_PROCESS && utp->ut_pid == mypid))  /* nothing */
		;

	if (utp) {
		memcpy(&ut, utp, sizeof(ut));
	} else {
		/* some inits don't initialize utmp... */
		memset(&ut, 0, sizeof(ut));
		safe_strncpy(ut.ut_id, line + 3, sizeof(ut.ut_id));
	}
	/*endutent(); */

	strcpy(ut.ut_user, "LOGIN");
	safe_strncpy(ut.ut_line, line, sizeof(ut.ut_line));
	if (fakehost)
		safe_strncpy(ut.ut_host, fakehost, sizeof(ut.ut_host));
	time(&t);
	ut.ut_time = t;
	ut.ut_type = LOGIN_PROCESS;
	ut.ut_pid = mypid;

	pututline(&ut);
	endutent();

#ifdef CONFIG_FEATURE_WTMP
	if (access(bb_path_wtmp_file, R_OK|W_OK) == -1)
		close(creat(bb_path_wtmp_file, 0664));
	updwtmp(bb_path_wtmp_file, &ut);
#endif
}

#endif /* CONFIG_FEATURE_UTMP */
#endif /* SYSV_STYLE */


#undef logname
int getty_main(int argc, char **argv)
{
	int nullfd;
	char *logname = NULL;           /* login name, given to /bin/login */
	struct chardata chardata;       /* set by get_logname() */
	struct termio termio;           /* terminal mode bits */
	static struct options options = {
		0,                      /* show /etc/issue (SYSV_STYLE) */
		0,                      /* no timeout */
		_PATH_LOGIN,            /* default login program */
		"tty1",                 /* default tty line */
		"",                     /* modem init string */
#ifdef ISSUE
		ISSUE,                  /* default issue file */
#else
		NULL,
#endif
		0,                      /* no baud rates known yet */
	};

	/* Already too late because of theoretical
	 * possibility of getty --help somehow triggered
	 * inadvertently before we reach this. Oh well. */
	close(0);
	close(1);
	close(2);
#ifdef __linux__
	setsid();
#endif
	/* We want special flavor of error_msg_and_die */
	die_sleep = 10;
	msg_eol = "\r\n";
	/* Was "/dev/console". Why should we spam *system console*
	 * if there is a problem with getty on /dev/ttyS15?... */
	nullfd = xopen(bb_dev_null, O_RDWR);
	dup2(nullfd, 0);
	dup2(nullfd, 1);
	dup2(nullfd, 2);
	if(nullfd > 2)
		close(nullfd);
	openlog(bb_applet_name, LOG_PID, LOG_AUTH);
	logmode = LOGMODE_BOTH;

#ifdef DEBUGGING
	dbf = xfopen(DEBUGTERM, "w");

	{
		int i;

		for (i = 1; i < argc; i++) {
			debug(argv[i]);
			debug("\n");
		}
	}
#endif

	/* Parse command-line arguments. */
	parse_args(argc, argv, &options);

#ifdef SYSV_STYLE
#ifdef CONFIG_FEATURE_UTMP
	/* Update the utmp file. */
	update_utmp(options.tty);
#endif
#endif

	debug("calling open_tty\n");
	/* Open the tty as standard { input, output, error }. */
	open_tty(options.tty, &termio, options.flags & F_LOCAL);

#ifdef __linux__
	{
		int iv;

		iv = getpid();
		ioctl(0, TIOCSPGRP, &iv);
	}
#endif
	/* Initialize the termio settings (raw mode, eight-bit, blocking i/o). */
	debug("calling termio_init\n");
	termio_init(&termio, options.speeds[FIRST_SPEED], &options);

	/* write the modem init string and DON'T flush the buffers */
	if (options.flags & F_INITSTRING) {
		debug("writing init string\n");
		write(1, options.initstring, strlen(options.initstring));
	}

	if (!(options.flags & F_LOCAL)) {
		/* go to blocking write mode unless -L is specified */
		fcntl(1, F_SETFL, fcntl(1, F_GETFL, 0) & ~O_NONBLOCK);
	}

	/* Optionally detect the baud rate from the modem status message. */
	debug("before autobaud\n");
	if (options.flags & F_PARSE)
		auto_baud(&termio);

	/* Set the optional timer. */
	if (options.timeout)
		(void) alarm((unsigned) options.timeout);

	/* optionally wait for CR or LF before writing /etc/issue */
	if (options.flags & F_WAITCRLF) {
		char ch;

		debug("waiting for cr-lf\n");
		while (read(0, &ch, 1) == 1) {
			ch &= 0x7f;                     /* strip "parity bit" */
#ifdef DEBUGGING
			fprintf(dbf, "read %c\n", ch);
#endif
			if (ch == '\n' || ch == '\r')
				break;
		}
	}

	chardata = init_chardata;
	if (!(options.flags & F_NOPROMPT)) {
		/* Read the login name. */
		debug("reading login name\n");
		/* while ((logname = get_logname(&options, &chardata, &termio)) == 0) */
		logname = get_logname(&options, &chardata, &termio);
		while (logname == NULL)
			next_speed(&termio, &options);
	}

	/* Disable timer. */

	if (options.timeout)
		(void) alarm(0);

	/* Finalize the termio settings. */

	termio_final(&options, &termio, &chardata);

	/* Now the newline character should be properly written. */

	(void) write(1, "\n", 1);

	/* Let the login program take care of password validation. */

	(void) execl(options.login, options.login, "--", logname, (char *) 0);
	bb_error_msg_and_die("%s: can't exec %s", options.tty, options.login);
}