source: branches/3.0/mindi-busybox/loginutils/getty.c @ 2899

Last change on this file since 2899 was 2725, checked in by bruno, 9 years ago
  • Update mindi-busybox to 1.18.3 to avoid problems with the tar command which is now failing on recent versions with busybox 1.7.3
File size: 22.3 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 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 source tree.
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        op->initstring = xstrdup(op->initstring);
192        /* decode \ddd octal codes into chars */
193        strcpy_and_process_escape_sequences((char*)op->initstring, op->initstring);
194    }
195    op->flags ^= F_ISSUE;           /* invert flag "show /etc/issue" */
196    debug("after getopt\n");
197
198    /* we loosen up a bit and accept both "baudrate tty" and "tty baudrate" */
199    op->tty = argv[0];      /* tty name */
200    ts = argv[1];           /* baud rate(s) */
201    if (isdigit(argv[0][0])) {
202        /* a number first, assume it's a speed (BSD style) */
203        op->tty = ts;   /* tty name is in argv[1] */
204        ts = argv[0];   /* baud rate(s) */
205    }
206    parse_speeds(op, ts);
207    applet_name = xasprintf("getty: %s", op->tty);
208
209    if (argv[2])
210        xsetenv("TERM", argv[2]);
211
212    debug("exiting parse_args\n");
213}
214
215/* open_tty - set up tty as standard { input, output, error } */
216static void open_tty(const char *tty)
217{
218    /* Set up new standard input, unless we are given an already opened port. */
219    if (NOT_LONE_DASH(tty)) {
220//      struct stat st;
221//      int cur_dir_fd;
222//      int fd;
223
224        /* Sanity checks... */
225//      cur_dir_fd = xopen(".", O_DIRECTORY | O_NONBLOCK);
226//      xchdir("/dev");
227//      xstat(tty, &st);
228//      if (!S_ISCHR(st.st_mode))
229//          bb_error_msg_and_die("not a character device");
230
231        if (tty[0] != '/')
232            tty = xasprintf("/dev/%s", tty); /* will leak it */
233
234        /* Open the tty as standard input. */
235        debug("open(2)\n");
236        close(0);
237        /*fd =*/ xopen(tty, O_RDWR | O_NONBLOCK); /* uses fd 0 */
238
239//      /* Restore current directory */
240//      fchdir(cur_dir_fd);
241
242        /* Open the tty as standard input, continued */
243//      xmove_fd(fd, 0);
244//      /* fd is >= cur_dir_fd, and cur_dir_fd gets closed too here: */
245//      while (fd > 2)
246//          close(fd--);
247
248        /* Set proper protections and ownership. */
249        fchown(0, 0, 0);        /* 0:0 */
250        fchmod(0, 0620);        /* crw--w---- */
251    } else {
252        /*
253         * Standard input should already be connected to an open port. Make
254         * sure it is open for read/write.
255         */
256        if ((fcntl(0, F_GETFL) & O_RDWR) != O_RDWR)
257            bb_error_msg_and_die("stdin is not open for read/write");
258    }
259}
260
261/* termios_init - initialize termios settings */
262static void termios_init(struct termios *tp, int speed, struct options *op)
263{
264    speed_t ispeed, ospeed;
265    /*
266     * Initial termios settings: 8-bit characters, raw-mode, blocking i/o.
267     * Special characters are set after we have read the login name; all
268     * reads will be done in raw mode anyway. Errors will be dealt with
269     * later on.
270     */
271    /* flush input and output queues, important for modems! */
272    tcflush(0, TCIOFLUSH);
273    ispeed = ospeed = speed;
274    if (speed == B0) {
275        /* Speed was specified as "0" on command line.
276         * Just leave it unchanged */
277        ispeed = cfgetispeed(tp);
278        ospeed = cfgetospeed(tp);
279    }
280    tp->c_cflag = CS8 | HUPCL | CREAD;
281    if (op->flags & F_LOCAL)
282        tp->c_cflag |= CLOCAL;
283    cfsetispeed(tp, ispeed);
284    cfsetospeed(tp, ospeed);
285
286    tp->c_iflag = tp->c_lflag = 0;
287    tp->c_oflag = OPOST | ONLCR;
288    tp->c_cc[VMIN] = 1;
289    tp->c_cc[VTIME] = 0;
290#ifdef __linux__
291    tp->c_line = 0;
292#endif
293
294    /* Optionally enable hardware flow control */
295#ifdef CRTSCTS
296    if (op->flags & F_RTSCTS)
297        tp->c_cflag |= CRTSCTS;
298#endif
299
300    tcsetattr_stdin_TCSANOW(tp);
301
302    debug("term_io 2\n");
303}
304
305/* auto_baud - extract baud rate from modem status message */
306static void auto_baud(char *buf, unsigned size_buf, struct termios *tp)
307{
308    int speed;
309    int vmin;
310    unsigned iflag;
311    char *bp;
312    int nread;
313
314    /*
315     * This works only if the modem produces its status code AFTER raising
316     * the DCD line, and if the computer is fast enough to set the proper
317     * baud rate before the message has gone by. We expect a message of the
318     * following format:
319     *
320     * <junk><number><junk>
321     *
322     * The number is interpreted as the baud rate of the incoming call. If the
323     * modem does not tell us the baud rate within one second, we will keep
324     * using the current baud rate. It is advisable to enable BREAK
325     * processing (comma-separated list of baud rates) if the processing of
326     * modem status messages is enabled.
327     */
328
329    /*
330     * Use 7-bit characters, don't block if input queue is empty. Errors will
331     * be dealt with later on.
332     */
333    iflag = tp->c_iflag;
334    tp->c_iflag |= ISTRIP;          /* enable 8th-bit stripping */
335    vmin = tp->c_cc[VMIN];
336    tp->c_cc[VMIN] = 0;             /* don't block if queue empty */
337    tcsetattr_stdin_TCSANOW(tp);
338
339    /*
340     * Wait for a while, then read everything the modem has said so far and
341     * try to extract the speed of the dial-in call.
342     */
343    sleep(1);
344    nread = safe_read(STDIN_FILENO, buf, size_buf - 1);
345    if (nread > 0) {
346        buf[nread] = '\0';
347        for (bp = buf; bp < buf + nread; bp++) {
348            if (isdigit(*bp)) {
349                speed = bcode(bp);
350                if (speed > 0)
351                    cfsetspeed(tp, speed);
352                break;
353            }
354        }
355    }
356
357    /* Restore terminal settings. Errors will be dealt with later on. */
358    tp->c_iflag = iflag;
359    tp->c_cc[VMIN] = vmin;
360    tcsetattr_stdin_TCSANOW(tp);
361}
362
363/* do_prompt - show login prompt, optionally preceded by /etc/issue contents */
364static void do_prompt(struct options *op)
365{
366#ifdef ISSUE
367    print_login_issue(op->issue, op->tty);
368#endif
369    print_login_prompt();
370}
371
372#ifdef HANDLE_ALLCAPS
373/* all_is_upcase - string contains upper case without lower case */
374/* returns 1 if true, 0 if false */
375static int all_is_upcase(const char *s)
376{
377    while (*s)
378        if (islower(*s++))
379            return 0;
380    return 1;
381}
382#endif
383
384/* get_logname - get user name, establish parity, speed, erase, kill, eol;
385 * return NULL on BREAK, logname on success */
386static char *get_logname(char *logname, unsigned size_logname,
387        struct options *op, struct chardata *cp)
388{
389    char *bp;
390    char c;                         /* input character, full eight bits */
391    char ascval;                    /* low 7 bits of input character */
392    int bits;                       /* # of "1" bits per character */
393    int mask;                       /* mask with 1 bit up */
394    static const char erase[][3] = {/* backspace-space-backspace */
395        "\010\040\010",                 /* space parity */
396        "\010\040\010",                 /* odd parity */
397        "\210\240\210",                 /* even parity */
398        "\010\040\010",                 /* 8 bit no parity */
399    };
400
401    /* NB: *cp is pre-initialized with init_chardata */
402
403    /* Flush pending input (esp. after parsing or switching the baud rate). */
404    sleep(1);
405    tcflush(0, TCIOFLUSH);
406
407    /* Prompt for and read a login name. */
408    logname[0] = '\0';
409    while (!logname[0]) {
410        /* Write issue file and prompt, with "parity" bit == 0. */
411        do_prompt(op);
412
413        /* Read name, watch for break, parity, erase, kill, end-of-line. */
414        bp = logname;
415        cp->eol = '\0';
416        while (cp->eol == '\0') {
417
418            /* Do not report trivial EINTR/EIO errors. */
419            errno = EINTR; /* make read of 0 bytes be silent too */
420            if (read(STDIN_FILENO, &c, 1) < 1) {
421                if (errno == EINTR || errno == EIO)
422                    exit(EXIT_SUCCESS);
423                bb_perror_msg_and_die(bb_msg_read_error);
424            }
425
426            /* BREAK. If we have speeds to try,
427             * return NULL (will switch speeds and return here) */
428            if (c == '\0' && op->numspeed > 1)
429                return NULL;
430
431            /* Do parity bit handling. */
432            if (!(op->flags & F_LOCAL) && (c & 0x80)) {       /* "parity" bit on? */
433                bits = 1;
434                mask = 1;
435                while (mask & 0x7f) {
436                    if (mask & c)
437                        bits++; /* count "1" bits */
438                    mask <<= 1;
439                }
440                /* ... |= 2 - even, 1 - odd */
441                cp->parity |= 2 - (bits & 1);
442            }
443
444            /* Do erase, kill and end-of-line processing. */
445            ascval = c & 0x7f;
446            switch (ascval) {
447            case CR:
448            case NL:
449                *bp = '\0';             /* terminate logname */
450                cp->eol = ascval;       /* set end-of-line char */
451                break;
452            case BS:
453            case DEL:
454#ifdef ANCIENT_BS_KILL_CHARS
455            case '#':
456#endif
457                cp->erase = ascval;     /* set erase character */
458                if (bp > logname) {
459                    full_write(STDOUT_FILENO, erase[cp->parity], 3);
460                    bp--;
461                }
462                break;
463            case CTL('U'):
464#ifdef ANCIENT_BS_KILL_CHARS
465            case '@':
466#endif
467                cp->kill = ascval;      /* set kill character */
468                while (bp > logname) {
469                    full_write(STDOUT_FILENO, erase[cp->parity], 3);
470                    bp--;
471                }
472                break;
473            case CTL('D'):
474                exit(EXIT_SUCCESS);
475            default:
476                if (ascval < ' ') {
477                    /* ignore garbage characters */
478                } else if ((int)(bp - logname) >= size_logname - 1) {
479                    bb_error_msg_and_die("input overrun");
480                } else {
481                    full_write(STDOUT_FILENO, &c, 1); /* echo the character */
482                    *bp++ = ascval; /* and store it */
483                }
484                break;
485            }
486        }
487    }
488    /* Handle names with upper case and no lower case. */
489
490#ifdef HANDLE_ALLCAPS
491    cp->capslock = all_is_upcase(logname);
492    if (cp->capslock) {
493        for (bp = logname; *bp; bp++)
494            if (isupper(*bp))
495                *bp = tolower(*bp);     /* map name to lower case */
496    }
497#endif
498    return logname;
499}
500
501/* termios_final - set the final tty mode bits */
502static void termios_final(struct options *op, struct termios *tp, struct chardata *cp)
503{
504    /* General terminal-independent stuff. */
505    tp->c_iflag |= IXON | IXOFF;    /* 2-way flow control */
506    tp->c_lflag |= ICANON | ISIG | ECHO | ECHOE | ECHOK | ECHOKE;
507    /* no longer| ECHOCTL | ECHOPRT */
508    tp->c_oflag |= OPOST;
509    /* tp->c_cflag = 0; */
510    tp->c_cc[VINTR] = DEF_INTR;     /* default interrupt */
511    tp->c_cc[VQUIT] = DEF_QUIT;     /* default quit */
512    tp->c_cc[VEOF] = DEF_EOF;       /* default EOF character */
513    tp->c_cc[VEOL] = DEF_EOL;
514#ifdef VSWTC
515    tp->c_cc[VSWTC] = DEF_SWITCH;   /* default switch character */
516#endif
517
518    /* Account for special characters seen in input. */
519    if (cp->eol == CR) {
520        tp->c_iflag |= ICRNL;   /* map CR in input to NL */
521        tp->c_oflag |= ONLCR;   /* map NL in output to CR-NL */
522    }
523    tp->c_cc[VERASE] = cp->erase;   /* set erase character */
524    tp->c_cc[VKILL] = cp->kill;     /* set kill character */
525
526    /* Account for the presence or absence of parity bits in input. */
527    switch (cp->parity) {
528    case 0:                                 /* space (always 0) parity */
529// I bet most people go here - they use only 7-bit chars in usernames....
530        break;
531    case 1:                                 /* odd parity */
532        tp->c_cflag |= PARODD;
533        /* FALLTHROUGH */
534    case 2:                                 /* even parity */
535        tp->c_cflag |= PARENB;
536        tp->c_iflag |= INPCK | ISTRIP;
537        /* FALLTHROUGH */
538    case (1 | 2):                           /* no parity bit */
539        tp->c_cflag &= ~CSIZE;
540        tp->c_cflag |= CS7;
541// FIXME: wtf? case 3: we saw both even and odd 8-bit bytes -
542// it's probably some umlauts etc, but definitely NOT 7-bit!!!
543// Entire parity detection madness here just begs for deletion...
544        break;
545    }
546
547    /* Account for upper case without lower case. */
548#ifdef HANDLE_ALLCAPS
549    if (cp->capslock) {
550        tp->c_iflag |= IUCLC;
551        tp->c_lflag |= XCASE;
552        tp->c_oflag |= OLCUC;
553    }
554#endif
555    /* Optionally enable hardware flow control */
556#ifdef CRTSCTS
557    if (op->flags & F_RTSCTS)
558        tp->c_cflag |= CRTSCTS;
559#endif
560
561    /* Finally, make the new settings effective */
562    if (tcsetattr_stdin_TCSANOW(tp) < 0)
563        bb_perror_msg_and_die("tcsetattr");
564}
565
566int getty_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
567int getty_main(int argc UNUSED_PARAM, char **argv)
568{
569    int n;
570    pid_t pid;
571    char *fakehost = NULL;          /* Fake hostname for ut_host */
572    char *logname;                  /* login name, given to /bin/login */
573    /* Merging these into "struct local" may _seem_ to reduce
574     * parameter passing, but today's gcc will inline
575     * statics which are called once anyway, so don't do that */
576    struct chardata chardata;       /* set by get_logname() */
577    struct termios termios;         /* terminal mode bits */
578    struct options options;
579
580    chardata = init_chardata;
581
582    memset(&options, 0, sizeof(options));
583    options.login = _PATH_LOGIN;    /* default login program */
584    options.tty = "tty1";           /* default tty line */
585    options.initstring = "";        /* modem init string */
586#ifdef ISSUE
587    options.issue = ISSUE;          /* default issue file */
588#endif
589
590    /* Parse command-line arguments. */
591    parse_args(argv, &options, &fakehost);
592
593    logmode = LOGMODE_NONE;
594
595    /* Create new session, lose controlling tty, if any */
596    /* docs/ctty.htm says:
597     * "This is allowed only when the current process
598     *  is not a process group leader" - is this a problem? */
599    setsid();
600    /* close stdio, and stray descriptors, just in case */
601    n = xopen(bb_dev_null, O_RDWR);
602    /* dup2(n, 0); - no, we need to handle "getty - 9600" too */
603    xdup2(n, 1);
604    xdup2(n, 2);
605    while (n > 2)
606        close(n--);
607
608    /* Logging. We want special flavor of error_msg_and_die */
609    die_sleep = 10;
610    msg_eol = "\r\n";
611    /* most likely will internally use fd #3 in CLOEXEC mode: */
612    openlog(applet_name, LOG_PID, LOG_AUTH);
613    logmode = LOGMODE_BOTH;
614
615#ifdef DEBUGGING
616    dbf = xfopen_for_write(DEBUGTERM);
617    for (n = 1; argv[n]; n++) {
618        debug(argv[n]);
619        debug("\n");
620    }
621#endif
622
623    /* Open the tty as standard input, if it is not "-" */
624    /* If it's not "-" and not taken yet, it will become our ctty */
625    debug("calling open_tty\n");
626    open_tty(options.tty);
627    ndelay_off(0);
628    debug("duping\n");
629    xdup2(0, 1);
630    xdup2(0, 2);
631
632    /*
633     * The following ioctl will fail if stdin is not a tty, but also when
634     * there is noise on the modem control lines. In the latter case, the
635     * common course of action is (1) fix your cables (2) give the modem more
636     * time to properly reset after hanging up. SunOS users can achieve (2)
637     * by patching the SunOS kernel variable "zsadtrlow" to a larger value;
638     * 5 seconds seems to be a good value.
639     */
640    if (tcgetattr(0, &termios) < 0)
641        bb_perror_msg_and_die("tcgetattr");
642
643    pid = getpid();
644#ifdef __linux__
645// FIXME: do we need this? Otherwise "-" case seems to be broken...
646    // /* Forcibly make fd 0 our controlling tty, even if another session
647    //  * has it as a ctty. (Another session loses ctty). */
648    // ioctl(0, TIOCSCTTY, (void*)1);
649    /* Make ourself a foreground process group within our session */
650    tcsetpgrp(0, pid);
651#endif
652
653    /* Update the utmp file. This tty is ours now! */
654    update_utmp(pid, LOGIN_PROCESS, options.tty, "LOGIN", fakehost);
655
656    /* Initialize the termios settings (raw mode, eight-bit, blocking i/o). */
657    debug("calling termios_init\n");
658    termios_init(&termios, options.speeds[0], &options);
659
660    /* Write the modem init string and DON'T flush the buffers */
661    if (options.flags & F_INITSTRING) {
662        debug("writing init string\n");
663        full_write1_str(options.initstring);
664    }
665
666    /* Optionally detect the baud rate from the modem status message */
667    debug("before autobaud\n");
668    if (options.flags & F_PARSE)
669        auto_baud(line_buf, sizeof(line_buf), &termios);
670
671    /* Set the optional timer */
672    alarm(options.timeout); /* if 0, alarm is not set */
673
674    /* Optionally wait for CR or LF before writing /etc/issue */
675    if (options.flags & F_WAITCRLF) {
676        char ch;
677
678        debug("waiting for cr-lf\n");
679        while (safe_read(STDIN_FILENO, &ch, 1) == 1) {
680            debug("read %x\n", (unsigned char)ch);
681            ch &= 0x7f;                     /* strip "parity bit" */
682            if (ch == '\n' || ch == '\r')
683                break;
684        }
685    }
686
687    logname = NULL;
688    if (!(options.flags & F_NOPROMPT)) {
689        /* NB:termios_init already set line speed
690         * to options.speeds[0] */
691        int baud_index = 0;
692
693        while (1) {
694            /* Read the login name. */
695            debug("reading login name\n");
696            logname = get_logname(line_buf, sizeof(line_buf),
697                    &options, &chardata);
698            if (logname)
699                break;
700            /* we are here only if options.numspeed > 1 */
701            baud_index = (baud_index + 1) % options.numspeed;
702            cfsetispeed(&termios, options.speeds[baud_index]);
703            cfsetospeed(&termios, options.speeds[baud_index]);
704            tcsetattr_stdin_TCSANOW(&termios);
705        }
706    }
707
708    /* Disable timer. */
709    alarm(0);
710
711    /* Finalize the termios settings. */
712    termios_final(&options, &termios, &chardata);
713
714    /* Now the newline character should be properly written. */
715    full_write(STDOUT_FILENO, "\n", 1);
716
717    /* Let the login program take care of password validation. */
718    /* We use PATH because we trust that root doesn't set "bad" PATH,
719     * and getty is not suid-root applet. */
720    /* With -n, logname == NULL, and login will ask for username instead */
721    BB_EXECLP(options.login, options.login, "--", logname, NULL);
722    bb_error_msg_and_die("can't execute '%s'", options.login);
723}
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