source: branches/2.2.5/mindi-busybox/loginutils/getty.c @ 1765

Last change on this file since 1765 was 1765, checked in by Bruno Cornec, 13 years ago

Update to busybox 1.7.2

File size: 23.2 KB
Line 
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}
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