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path: root/loginutils/getty.c (plain)
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1/* vi: set sw=4 ts=4: */
2/*
3 * Based on agetty - another getty program for Linux. By W. Z. Venema 1989
4 * Ported to Linux by Peter Orbaek <poe@daimi.aau.dk>
5 * This program is freely distributable.
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 * - Enabled hardware flow control before displaying /etc/issue
14 *
15 * 2011-01 Venys Vlasenko
16 * - Removed parity detection code. It can't work reliably:
17 * if all chars received have bit 7 cleared and odd (or even) parity,
18 * it is impossible to determine whether other side is 8-bit,no-parity
19 * or 7-bit,odd(even)-parity. It also interferes with non-ASCII usernames.
20 * - From now on, we assume that parity is correctly set.
21 *
22 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
23 */
24
25#include "libbb.h"
26#include <syslog.h>
27#ifndef IUCLC
28# define IUCLC 0
29#endif
30
31#ifndef LOGIN_PROCESS
32# undef ENABLE_FEATURE_UTMP
33# undef ENABLE_FEATURE_WTMP
34# define ENABLE_FEATURE_UTMP 0
35# define ENABLE_FEATURE_WTMP 0
36#endif
37
38
39/* The following is used for understandable diagnostics */
40#ifdef DEBUGGING
41static FILE *dbf;
42# define DEBUGTERM "/dev/ttyp0"
43# define debug(...) do { fprintf(dbf, __VA_ARGS__); fflush(dbf); } while (0)
44#else
45# define debug(...) ((void)0)
46#endif
47
48
49/*
50 * Things you may want to modify.
51 *
52 * You may disagree with the default line-editing etc. characters defined
53 * below. Note, however, that DEL cannot be used for interrupt generation
54 * and for line editing at the same time.
55 */
56#undef _PATH_LOGIN
57#ifdef __BIONIC__
58#define cfsetspeed(t,s) cfsetispeed(t,s)
59#define _PATH_LOGIN "/system/xbin/login"
60#else
61#define _PATH_LOGIN "/bin/login"
62#endif
63
64/* Displayed before the login prompt.
65 * If ISSUE is not defined, getty will never display the contents of the
66 * /etc/issue file. You will not want to spit out large "issue" files at the
67 * wrong baud rate.
68 */
69#define ISSUE "/etc/issue"
70
71/* Macro to build Ctrl-LETTER. Assumes ASCII dialect */
72#define CTL(x) ((x) ^ 0100)
73
74/*
75 * When multiple baud rates are specified on the command line,
76 * the first one we will try is the first one specified.
77 */
78#define MAX_SPEED 10 /* max. nr. of baud rates */
79
80struct globals {
81 unsigned timeout;
82 const char *login; /* login program */
83 const char *fakehost;
84 const char *tty_name;
85 char *initstring; /* modem init string */
86 const char *issue; /* alternative issue file */
87 int numspeed; /* number of baud rates to try */
88 int speeds[MAX_SPEED]; /* baud rates to be tried */
89 unsigned char eol; /* end-of-line char seen (CR or NL) */
90 struct termios tty_attrs;
91 char line_buf[128];
92};
93
94#define G (*ptr_to_globals)
95#define INIT_G() do { \
96 SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \
97} while (0)
98
99//usage:#define getty_trivial_usage
100//usage: "[OPTIONS] BAUD_RATE[,BAUD_RATE]... TTY [TERMTYPE]"
101//usage:#define getty_full_usage "\n\n"
102//usage: "Open TTY, prompt for login name, then invoke /system/xbin/login\n"
103//usage: "\n -h Enable hardware RTS/CTS flow control"
104//usage: "\n -L Set CLOCAL (ignore Carrier Detect state)"
105//usage: "\n -m Get baud rate from modem's CONNECT status message"
106//usage: "\n -n Don't prompt for login name"
107//usage: "\n -w Wait for CR or LF before sending /etc/issue"
108//usage: "\n -i Don't display /etc/issue"
109//usage: "\n -f ISSUE_FILE Display ISSUE_FILE instead of /etc/issue"
110//usage: "\n -l LOGIN Invoke LOGIN instead of /system/xbin/login"
111//usage: "\n -t SEC Terminate after SEC if no login name is read"
112//usage: "\n -I INITSTR Send INITSTR before anything else"
113//usage: "\n -H HOST Log HOST into the utmp file as the hostname"
114//usage: "\n"
115//usage: "\nBAUD_RATE of 0 leaves it unchanged"
116
117static const char opt_string[] ALIGN1 = "I:LH:f:hil:mt:wn";
118#define F_INITSTRING (1 << 0) /* -I */
119#define F_LOCAL (1 << 1) /* -L */
120#define F_FAKEHOST (1 << 2) /* -H */
121#define F_CUSTISSUE (1 << 3) /* -f */
122#define F_RTSCTS (1 << 4) /* -h */
123#define F_NOISSUE (1 << 5) /* -i */
124#define F_LOGIN (1 << 6) /* -l */
125#define F_PARSE (1 << 7) /* -m */
126#define F_TIMEOUT (1 << 8) /* -t */
127#define F_WAITCRLF (1 << 9) /* -w */
128#define F_NOPROMPT (1 << 10) /* -n */
129
130
131/* convert speed string to speed code; return <= 0 on failure */
132static int bcode(const char *s)
133{
134 int value = bb_strtou(s, NULL, 10); /* yes, int is intended! */
135 if (value < 0) /* bad terminating char, overflow, etc */
136 return value;
137 return tty_value_to_baud(value);
138}
139
140/* parse alternate baud rates */
141static void parse_speeds(char *arg)
142{
143 char *cp;
144
145 /* NB: at least one iteration is always done */
146 debug("entered parse_speeds\n");
147 while ((cp = strsep(&arg, ",")) != NULL) {
148 G.speeds[G.numspeed] = bcode(cp);
149 if (G.speeds[G.numspeed] < 0)
150 bb_error_msg_and_die("bad speed: %s", cp);
151 /* note: arg "0" turns into speed B0 */
152 G.numspeed++;
153 if (G.numspeed > MAX_SPEED)
154 bb_error_msg_and_die("too many alternate speeds");
155 }
156 debug("exiting parse_speeds\n");
157}
158
159/* parse command-line arguments */
160static void parse_args(char **argv)
161{
162 char *ts;
163 int flags;
164
165 opt_complementary = "-2:t+"; /* at least 2 args; -t N */
166 flags = getopt32(argv, opt_string,
167 &G.initstring, &G.fakehost, &G.issue,
168 &G.login, &G.timeout
169 );
170 if (flags & F_INITSTRING) {
171 G.initstring = xstrdup(G.initstring);
172 /* decode \ddd octal codes into chars */
173 strcpy_and_process_escape_sequences(G.initstring, G.initstring);
174 }
175 argv += optind;
176 debug("after getopt\n");
177
178 /* We loosen up a bit and accept both "baudrate tty" and "tty baudrate" */
179 G.tty_name = argv[0];
180 ts = argv[1]; /* baud rate(s) */
181 if (isdigit(argv[0][0])) {
182 /* A number first, assume it's a speed (BSD style) */
183 G.tty_name = ts; /* tty name is in argv[1] */
184 ts = argv[0]; /* baud rate(s) */
185 }
186 parse_speeds(ts);
187
188 if (argv[2])
189 xsetenv("TERM", argv[2]);
190
191 debug("exiting parse_args\n");
192}
193
194/* set up tty as standard input, output, error */
195static void open_tty(void)
196{
197 /* Set up new standard input, unless we are given an already opened port */
198 if (NOT_LONE_DASH(G.tty_name)) {
199 if (G.tty_name[0] != '/')
200 G.tty_name = xasprintf("/dev/%s", G.tty_name); /* will leak it */
201
202 /* Open the tty as standard input */
203 debug("open(2)\n");
204 close(0);
205 xopen(G.tty_name, O_RDWR | O_NONBLOCK); /* uses fd 0 */
206
207 /* Set proper protections and ownership */
208 fchown(0, 0, 0); /* 0:0 */
209 fchmod(0, 0620); /* crw--w---- */
210 } else {
211 char *n;
212 /*
213 * Standard input should already be connected to an open port.
214 * Make sure it is open for read/write.
215 */
216 if ((fcntl(0, F_GETFL) & (O_RDWR|O_RDONLY|O_WRONLY)) != O_RDWR)
217 bb_error_msg_and_die("stdin is not open for read/write");
218
219 /* Try to get real tty name instead of "-" */
220 n = xmalloc_ttyname(0);
221 if (n)
222 G.tty_name = n;
223 }
224 applet_name = xasprintf("getty: %s", skip_dev_pfx(G.tty_name));
225}
226
227static void set_tty_attrs(void)
228{
229 if (tcsetattr_stdin_TCSANOW(&G.tty_attrs) < 0)
230 bb_perror_msg_and_die("tcsetattr");
231}
232
233/* We manipulate tty_attrs this way:
234 * - first, we read existing tty_attrs
235 * - init_tty_attrs modifies some parts and sets it
236 * - auto_baud and/or BREAK processing can set different speed and set tty attrs
237 * - finalize_tty_attrs again modifies some parts and sets tty attrs before
238 * execing login
239 */
240static void init_tty_attrs(int speed)
241{
242 /* Try to drain output buffer, with 5 sec timeout.
243 * Added on request from users of ~600 baud serial interface
244 * with biggish buffer on a 90MHz CPU.
245 * They were losing hundreds of bytes of buffered output
246 * on tcflush.
247 */
248 signal_no_SA_RESTART_empty_mask(SIGALRM, record_signo);
249 alarm(5);
250 tcdrain(STDIN_FILENO);
251 alarm(0);
252
253 /* Flush input and output queues, important for modems! */
254 tcflush(STDIN_FILENO, TCIOFLUSH);
255
256 /* Set speed if it wasn't specified as "0" on command line */
257 if (speed != B0)
258 cfsetspeed(&G.tty_attrs, speed);
259
260 /* Initial settings: 8-bit characters, raw mode, blocking i/o.
261 * Special characters are set after we have read the login name; all
262 * reads will be done in raw mode anyway.
263 */
264 /* Clear all bits except: */
265 G.tty_attrs.c_cflag &= (0
266 /* 2 stop bits (1 otherwise)
267 * Enable parity bit (both on input and output)
268 * Odd parity (else even)
269 */
270 | CSTOPB | PARENB | PARODD
271#ifdef CMSPAR
272 | CMSPAR /* mark or space parity */
273#endif
274#ifdef CBAUD
275 | CBAUD /* (output) baud rate */
276#endif
277#ifdef CBAUDEX
278 | CBAUDEX /* (output) baud rate */
279#endif
280#ifdef CIBAUD
281 | CIBAUD /* input baud rate */
282#endif
283 );
284 /* Set: 8 bits; hang up (drop DTR) on last close; enable receive */
285 G.tty_attrs.c_cflag |= CS8 | HUPCL | CREAD;
286 if (option_mask32 & F_LOCAL) {
287 /* ignore Carrier Detect pin:
288 * opens don't block when CD is low,
289 * losing CD doesn't hang up processes whose ctty is this tty
290 */
291 G.tty_attrs.c_cflag |= CLOCAL;
292 }
293#ifdef CRTSCTS
294 if (option_mask32 & F_RTSCTS)
295 G.tty_attrs.c_cflag |= CRTSCTS; /* flow control using RTS/CTS pins */
296#endif
297 G.tty_attrs.c_iflag = 0;
298 G.tty_attrs.c_lflag = 0;
299 /* non-raw output; add CR to each NL */
300 G.tty_attrs.c_oflag = OPOST | ONLCR;
301
302 /* reads would block only if < 1 char is available */
303 G.tty_attrs.c_cc[VMIN] = 1;
304 /* no timeout (reads block forever) */
305 G.tty_attrs.c_cc[VTIME] = 0;
306#ifdef __linux__
307 G.tty_attrs.c_line = 0;
308#endif
309
310 set_tty_attrs();
311
312 debug("term_io 2\n");
313}
314
315static void finalize_tty_attrs(void)
316{
317 /* software flow control on output (stop sending if XOFF is recvd);
318 * and on input (send XOFF when buffer is full)
319 */
320 G.tty_attrs.c_iflag |= IXON | IXOFF;
321 if (G.eol == '\r') {
322 G.tty_attrs.c_iflag |= ICRNL; /* map CR on input to NL */
323 }
324 /* Other bits in c_iflag:
325 * IXANY Any recvd char enables output (any char is also a XON)
326 * INPCK Enable parity check
327 * IGNPAR Ignore parity errors (drop bad bytes)
328 * PARMRK Mark parity errors with 0xff, 0x00 prefix
329 * (else bad byte is received as 0x00)
330 * ISTRIP Strip parity bit
331 * IGNBRK Ignore break condition
332 * BRKINT Send SIGINT on break - maybe set this?
333 * INLCR Map NL to CR
334 * IGNCR Ignore CR
335 * ICRNL Map CR to NL
336 * IUCLC Map uppercase to lowercase
337 * IMAXBEL Echo BEL on input line too long
338 * IUTF8 Appears to affect tty's idea of char widths,
339 * observed to improve backspacing through Unicode chars
340 */
341
342 /* line buffered input (NL or EOL or EOF chars end a line);
343 * recognize INT/QUIT/SUSP chars;
344 * echo input chars;
345 * echo BS-SP-BS on erase character;
346 * echo kill char specially, not as ^c (ECHOKE controls how exactly);
347 * erase all input via BS-SP-BS on kill char (else go to next line)
348 */
349 G.tty_attrs.c_lflag |= ICANON | ISIG | ECHO | ECHOE | ECHOK | ECHOKE;
350 /* Other bits in c_lflag:
351 * XCASE Map uppercase to \lowercase [tried, doesn't work]
352 * ECHONL Echo NL even if ECHO is not set
353 * ECHOCTL Echo ctrl chars as ^c (else don't echo) - maybe set this?
354 * ECHOPRT On erase, echo erased chars
355 * [qwe<BS><BS><BS> input looks like "qwe\ewq/" on screen]
356 * NOFLSH Don't flush input buffer after interrupt or quit chars
357 * IEXTEN Enable extended functions (??)
358 * [glibc says it enables c_cc[LNEXT] "enter literal char"
359 * and c_cc[VDISCARD] "toggle discard buffered output" chars]
360 * FLUSHO Output being flushed (c_cc[VDISCARD] is in effect)
361 * PENDIN Retype pending input at next read or input char
362 * (c_cc[VREPRINT] is being processed)
363 * TOSTOP Send SIGTTOU for background output
364 * (why "stty sane" unsets this bit?)
365 */
366
367 G.tty_attrs.c_cc[VINTR] = CTL('C');
368 G.tty_attrs.c_cc[VQUIT] = CTL('\\');
369 G.tty_attrs.c_cc[VEOF] = CTL('D');
370 G.tty_attrs.c_cc[VEOL] = '\n';
371#ifdef VSWTC
372 G.tty_attrs.c_cc[VSWTC] = 0;
373#endif
374#ifdef VSWTCH
375 G.tty_attrs.c_cc[VSWTCH] = 0;
376#endif
377 G.tty_attrs.c_cc[VKILL] = CTL('U');
378 /* Other control chars:
379 * VEOL2
380 * VERASE, VWERASE - (word) erase. we may set VERASE in get_logname
381 * VREPRINT - reprint current input buffer
382 * VLNEXT, VDISCARD, VSTATUS
383 * VSUSP, VDSUSP - send (delayed) SIGTSTP
384 * VSTART, VSTOP - chars used for IXON/IXOFF
385 */
386
387 set_tty_attrs();
388
389 /* Now the newline character should be properly written */
390 full_write(STDOUT_FILENO, "\n", 1);
391}
392
393/* extract baud rate from modem status message */
394static void auto_baud(void)
395{
396 int nread;
397
398 /*
399 * This works only if the modem produces its status code AFTER raising
400 * the DCD line, and if the computer is fast enough to set the proper
401 * baud rate before the message has gone by. We expect a message of the
402 * following format:
403 *
404 * <junk><number><junk>
405 *
406 * The number is interpreted as the baud rate of the incoming call. If the
407 * modem does not tell us the baud rate within one second, we will keep
408 * using the current baud rate. It is advisable to enable BREAK
409 * processing (comma-separated list of baud rates) if the processing of
410 * modem status messages is enabled.
411 */
412
413 G.tty_attrs.c_cc[VMIN] = 0; /* don't block reads (min read is 0 chars) */
414 set_tty_attrs();
415
416 /*
417 * Wait for a while, then read everything the modem has said so far and
418 * try to extract the speed of the dial-in call.
419 */
420 sleep(1);
421 nread = safe_read(STDIN_FILENO, G.line_buf, sizeof(G.line_buf) - 1);
422 if (nread > 0) {
423 int speed;
424 char *bp;
425 G.line_buf[nread] = '\0';
426 for (bp = G.line_buf; bp < G.line_buf + nread; bp++) {
427 if (isdigit(*bp)) {
428 speed = bcode(bp);
429 if (speed > 0)
430 cfsetspeed(&G.tty_attrs, speed);
431 break;
432 }
433 }
434 }
435
436 /* Restore terminal settings */
437 G.tty_attrs.c_cc[VMIN] = 1; /* restore to value set by init_tty_attrs */
438 set_tty_attrs();
439}
440
441/* get user name, establish parity, speed, erase, kill, eol;
442 * return NULL on BREAK, logname on success
443 */
444static char *get_logname(void)
445{
446 char *bp;
447 char c;
448
449 /* Flush pending input (esp. after parsing or switching the baud rate) */
450 usleep(100*1000); /* 0.1 sec */
451 tcflush(STDIN_FILENO, TCIFLUSH);
452
453 /* Prompt for and read a login name */
454 do {
455 /* Write issue file and prompt */
456#ifdef ISSUE
457 if (!(option_mask32 & F_NOISSUE))
458 print_login_issue(G.issue, G.tty_name);
459#endif
460 print_login_prompt();
461
462 /* Read name, watch for break, erase, kill, end-of-line */
463 bp = G.line_buf;
464 while (1) {
465 /* Do not report trivial EINTR/EIO errors */
466 errno = EINTR; /* make read of 0 bytes be silent too */
467 if (read(STDIN_FILENO, &c, 1) < 1) {
468 finalize_tty_attrs();
469 if (errno == EINTR || errno == EIO)
470 exit(EXIT_SUCCESS);
471 bb_perror_msg_and_die(bb_msg_read_error);
472 }
473
474 switch (c) {
475 case '\r':
476 case '\n':
477 *bp = '\0';
478 G.eol = c;
479 goto got_logname;
480 case CTL('H'):
481 case 0x7f:
482 G.tty_attrs.c_cc[VERASE] = c;
483 if (bp > G.line_buf) {
484 full_write(STDOUT_FILENO, "\010 \010", 3);
485 bp--;
486 }
487 break;
488 case CTL('U'):
489 while (bp > G.line_buf) {
490 full_write(STDOUT_FILENO, "\010 \010", 3);
491 bp--;
492 }
493 break;
494 case CTL('C'):
495 case CTL('D'):
496 finalize_tty_attrs();
497 exit(EXIT_SUCCESS);
498 case '\0':
499 /* BREAK. If we have speeds to try,
500 * return NULL (will switch speeds and return here) */
501 if (G.numspeed > 1)
502 return NULL;
503 /* fall through and ignore it */
504 default:
505 if ((unsigned char)c < ' ') {
506 /* ignore garbage characters */
507 } else if ((int)(bp - G.line_buf) < (int)sizeof(G.line_buf) - 1) {
508 /* echo and store the character */
509 full_write(STDOUT_FILENO, &c, 1);
510 *bp++ = c;
511 }
512 break;
513 }
514 } /* end of get char loop */
515 got_logname: ;
516 } while (G.line_buf[0] == '\0'); /* while logname is empty */
517
518 return G.line_buf;
519}
520
521static void alarm_handler(int sig UNUSED_PARAM)
522{
523 finalize_tty_attrs();
524 _exit(EXIT_SUCCESS);
525}
526
527int getty_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
528int getty_main(int argc UNUSED_PARAM, char **argv)
529{
530 int n;
531 pid_t pid, tsid;
532 char *logname;
533
534 INIT_G();
535 G.login = _PATH_LOGIN; /* default login program */
536#ifdef ISSUE
537 G.issue = ISSUE; /* default issue file */
538#endif
539 G.eol = '\r';
540
541 /* Parse command-line arguments */
542 parse_args(argv);
543
544 /* Create new session and pgrp, lose controlling tty */
545 pid = setsid(); /* this also gives us our pid :) */
546 if (pid < 0) {
547 int fd;
548 /* :(
549 * docs/ctty.htm says:
550 * "This is allowed only when the current process
551 * is not a process group leader".
552 * Thus, setsid() will fail if we _already_ are
553 * a session leader - which is quite possible for getty!
554 */
555 pid = getpid();
556 if (getsid(0) != pid) {
557 //for debugging:
558 //bb_perror_msg_and_die("setsid failed:"
559 // " pid %d ppid %d"
560 // " sid %d pgid %d",
561 // pid, getppid(),
562 // getsid(0), getpgid(0));
563 bb_perror_msg_and_die("setsid");
564 }
565 /* Looks like we are already a session leader.
566 * In this case (setsid failed) we may still have ctty,
567 * and it may be different from tty we need to control!
568 * If we still have ctty, on Linux ioctl(TIOCSCTTY)
569 * (which we are going to use a bit later) always fails -
570 * even if we try to take ctty which is already ours!
571 * Try to drop old ctty now to prevent that.
572 * Use O_NONBLOCK: old ctty may be a serial line.
573 */
574 fd = open("/dev/tty", O_RDWR | O_NONBLOCK);
575 if (fd >= 0) {
576 /* TIOCNOTTY sends SIGHUP to the foreground
577 * process group - which may include us!
578 * Make sure to not die on it:
579 */
580 sighandler_t old = signal(SIGHUP, SIG_IGN);
581 ioctl(fd, TIOCNOTTY);
582 close(fd);
583 signal(SIGHUP, old);
584 }
585 }
586
587 /* Close stdio, and stray descriptors, just in case */
588 n = xopen(bb_dev_null, O_RDWR);
589 /* dup2(n, 0); - no, we need to handle "getty - 9600" too */
590 xdup2(n, 1);
591 xdup2(n, 2);
592 while (n > 2)
593 close(n--);
594
595 /* Logging. We want special flavor of error_msg_and_die */
596 die_sleep = 10;
597 msg_eol = "\r\n";
598 /* most likely will internally use fd #3 in CLOEXEC mode: */
599 openlog(applet_name, LOG_PID, LOG_AUTH);
600 logmode = LOGMODE_BOTH;
601
602#ifdef DEBUGGING
603 dbf = xfopen_for_write(DEBUGTERM);
604 for (n = 1; argv[n]; n++) {
605 debug(argv[n]);
606 debug("\n");
607 }
608#endif
609
610 /* Open the tty as standard input, if it is not "-" */
611 debug("calling open_tty\n");
612 open_tty();
613 ndelay_off(STDIN_FILENO);
614 debug("duping\n");
615 xdup2(STDIN_FILENO, 1);
616 xdup2(STDIN_FILENO, 2);
617
618 /* Steal ctty if we don't have it yet */
619 tsid = tcgetsid(STDIN_FILENO);
620 if (tsid < 0 || pid != tsid) {
621 if (ioctl(STDIN_FILENO, TIOCSCTTY, /*force:*/ (long)1) < 0)
622 bb_perror_msg_and_die("TIOCSCTTY");
623 }
624
625#ifdef __linux__
626 /* Make ourself a foreground process group within our session */
627 if (tcsetpgrp(STDIN_FILENO, pid) < 0)
628 bb_perror_msg_and_die("tcsetpgrp");
629#endif
630
631 /*
632 * The following ioctl will fail if stdin is not a tty, but also when
633 * there is noise on the modem control lines. In the latter case, the
634 * common course of action is (1) fix your cables (2) give the modem more
635 * time to properly reset after hanging up. SunOS users can achieve (2)
636 * by patching the SunOS kernel variable "zsadtrlow" to a larger value;
637 * 5 seconds seems to be a good value.
638 */
639 if (tcgetattr(STDIN_FILENO, &G.tty_attrs) < 0)
640 bb_perror_msg_and_die("tcgetattr");
641
642 /* Update the utmp file. This tty is ours now! */
643 update_utmp(pid, LOGIN_PROCESS, G.tty_name, "LOGIN", G.fakehost);
644
645 /* Initialize tty attrs (raw mode, eight-bit, blocking i/o) */
646 debug("calling init_tty_attrs\n");
647 init_tty_attrs(G.speeds[0]);
648
649 /* Write the modem init string and DON'T flush the buffers */
650 if (option_mask32 & F_INITSTRING) {
651 debug("writing init string\n");
652 full_write1_str(G.initstring);
653 }
654
655 /* Optionally detect the baud rate from the modem status message */
656 debug("before autobaud\n");
657 if (option_mask32 & F_PARSE)
658 auto_baud();
659
660 /* Set the optional timer */
661 signal(SIGALRM, alarm_handler);
662 alarm(G.timeout); /* if 0, alarm is not set */
663
664 /* Optionally wait for CR or LF before writing /etc/issue */
665 if (option_mask32 & F_WAITCRLF) {
666 char ch;
667 debug("waiting for cr-lf\n");
668 while (safe_read(STDIN_FILENO, &ch, 1) == 1) {
669 debug("read %x\n", (unsigned char)ch);
670 if (ch == '\n' || ch == '\r')
671 break;
672 }
673 }
674
675 logname = NULL;
676 if (!(option_mask32 & F_NOPROMPT)) {
677 /* NB: init_tty_attrs already set line speed
678 * to G.speeds[0] */
679 int baud_index = 0;
680
681 while (1) {
682 /* Read the login name */
683 debug("reading login name\n");
684 logname = get_logname();
685 if (logname)
686 break;
687 /* We are here only if G.numspeed > 1 */
688 baud_index = (baud_index + 1) % G.numspeed;
689 cfsetspeed(&G.tty_attrs, G.speeds[baud_index]);
690 set_tty_attrs();
691 }
692 }
693
694 /* Disable timer */
695 alarm(0);
696
697 finalize_tty_attrs();
698
699 /* Let the login program take care of password validation */
700 /* We use PATH because we trust that root doesn't set "bad" PATH,
701 * and getty is not suid-root applet */
702 /* With -n, logname == NULL, and login will ask for username instead */
703 BB_EXECLP(G.login, G.login, "--", logname, (char *)0);
704 bb_error_msg_and_die("can't execute '%s'", G.login);
705}
706
generated by cgit at 2024-05-16 00:14:02 (GMT)