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 //config:config GETTY
25 //config: bool "getty"
26 //config: default y
27 //config: select FEATURE_SYSLOG
28 //config: help
29 //config: getty lets you log in on a tty. It is normally invoked by init.
30 //config:
31 //config: Note that you can save a few bytes by disabling it and
32 //config: using login applet directly.
33 //config: If you need to reset tty attributes before calling login,
34 //config: this script approximates getty:
35 //config:
36 //config: exec </dev/$1 >/dev/$1 2>&1 || exit 1
37 //config: reset
38 //config: stty sane; stty ispeed 38400; stty ospeed 38400
39 //config: printf "%s login: " "`hostname`"
40 //config: read -r login
41 //config: exec /bin/login "$login"
42
43 //applet:IF_GETTY(APPLET(getty, BB_DIR_SBIN, BB_SUID_DROP))
44
45 //kbuild:lib-$(CONFIG_GETTY) += getty.o
46
47 #include "libbb.h"
48 #include <syslog.h>
49 #ifndef IUCLC
50 # define IUCLC 0
51 #endif
52
53 #ifndef LOGIN_PROCESS
54 # undef ENABLE_FEATURE_UTMP
55 # undef ENABLE_FEATURE_WTMP
56 # define ENABLE_FEATURE_UTMP 0
57 # define ENABLE_FEATURE_WTMP 0
58 #endif
59
60
61 /* The following is used for understandable diagnostics */
62 #ifdef DEBUGGING
63 static FILE *dbf;
64 # define DEBUGTERM "/dev/ttyp0"
65 # define debug(...) do { fprintf(dbf, __VA_ARGS__); fflush(dbf); } while (0)
66 #else
67 # define debug(...) ((void)0)
68 #endif
69
70
71 /*
72 * Things you may want to modify.
73 *
74 * You may disagree with the default line-editing etc. characters defined
75 * below. Note, however, that DEL cannot be used for interrupt generation
76 * and for line editing at the same time.
77 */
78 #undef _PATH_LOGIN
79 #define _PATH_LOGIN "/bin/login"
80
81 /* Displayed before the login prompt.
82 * If ISSUE is not defined, getty will never display the contents of the
83 * /etc/issue file. You will not want to spit out large "issue" files at the
84 * wrong baud rate.
85 */
86 #define ISSUE "/etc/issue"
87
88 /* Macro to build Ctrl-LETTER. Assumes ASCII dialect */
89 #define CTL(x) ((x) ^ 0100)
90
91 /*
92 * When multiple baud rates are specified on the command line,
93 * the first one we will try is the first one specified.
94 */
95 #define MAX_SPEED 10 /* max. nr. of baud rates */
96
97 struct globals {
98 unsigned timeout;
99 const char *login; /* login program */
100 const char *fakehost;
101 const char *tty_name;
102 char *initstring; /* modem init string */
103 const char *issue; /* alternative issue file */
104 int numspeed; /* number of baud rates to try */
105 int speeds[MAX_SPEED]; /* baud rates to be tried */
106 unsigned char eol; /* end-of-line char seen (CR or NL) */
107 struct termios tty_attrs;
108 char line_buf[128];
109 };
110
111 #define G (*ptr_to_globals)
112 #define INIT_G() do { \
113 SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \
114 } while (0)
115
116 //usage:#define getty_trivial_usage
117 //usage: "[OPTIONS] BAUD_RATE[,BAUD_RATE]... TTY [TERMTYPE]"
118 //usage:#define getty_full_usage "\n\n"
119 //usage: "Open TTY, prompt for login name, then invoke /bin/login\n"
120 //usage: "\n -h Enable hardware RTS/CTS flow control"
121 //usage: "\n -L Set CLOCAL (ignore Carrier Detect state)"
122 //usage: "\n -m Get baud rate from modem's CONNECT status message"
123 //usage: "\n -n Don't prompt for login name"
124 //usage: "\n -w Wait for CR or LF before sending /etc/issue"
125 //usage: "\n -i Don't display /etc/issue"
126 //usage: "\n -f ISSUE_FILE Display ISSUE_FILE instead of /etc/issue"
127 //usage: "\n -l LOGIN Invoke LOGIN instead of /bin/login"
128 //usage: "\n -t SEC Terminate after SEC if no login name is read"
129 //usage: "\n -I INITSTR Send INITSTR before anything else"
130 //usage: "\n -H HOST Log HOST into the utmp file as the hostname"
131 //usage: "\n"
132 //usage: "\nBAUD_RATE of 0 leaves it unchanged"
133
134 static const char opt_string[] ALIGN1 = "I:LH:f:hil:mt:+wn";
135 #define F_INITSTRING (1 << 0) /* -I */
136 #define F_LOCAL (1 << 1) /* -L */
137 #define F_FAKEHOST (1 << 2) /* -H */
138 #define F_CUSTISSUE (1 << 3) /* -f */
139 #define F_RTSCTS (1 << 4) /* -h */
140 #define F_NOISSUE (1 << 5) /* -i */
141 #define F_LOGIN (1 << 6) /* -l */
142 #define F_PARSE (1 << 7) /* -m */
143 #define F_TIMEOUT (1 << 8) /* -t */
144 #define F_WAITCRLF (1 << 9) /* -w */
145 #define F_NOPROMPT (1 << 10) /* -n */
146
147
148 /* convert speed string to speed code; return <= 0 on failure */
bcode(const char * s)149 static int bcode(const char *s)
150 {
151 int value = bb_strtou(s, NULL, 10); /* yes, int is intended! */
152 if (value < 0) /* bad terminating char, overflow, etc */
153 return value;
154 return tty_value_to_baud(value);
155 }
156
157 /* parse alternate baud rates */
parse_speeds(char * arg)158 static void parse_speeds(char *arg)
159 {
160 char *cp;
161
162 /* NB: at least one iteration is always done */
163 debug("entered parse_speeds\n");
164 while ((cp = strsep(&arg, ",")) != NULL) {
165 G.speeds[G.numspeed] = bcode(cp);
166 if (G.speeds[G.numspeed] < 0)
167 bb_error_msg_and_die("bad speed: %s", cp);
168 /* note: arg "0" turns into speed B0 */
169 G.numspeed++;
170 if (G.numspeed > MAX_SPEED)
171 bb_error_msg_and_die("too many alternate speeds");
172 }
173 debug("exiting parse_speeds\n");
174 }
175
176 /* parse command-line arguments */
parse_args(char ** argv)177 static void parse_args(char **argv)
178 {
179 char *ts;
180 int flags;
181
182 opt_complementary = "-2"; /* at least 2 args; -t N */
183 flags = getopt32(argv, opt_string,
184 &G.initstring, &G.fakehost, &G.issue,
185 &G.login, &G.timeout
186 );
187 if (flags & F_INITSTRING) {
188 G.initstring = xstrdup(G.initstring);
189 /* decode \ddd octal codes into chars */
190 strcpy_and_process_escape_sequences(G.initstring, G.initstring);
191 }
192 argv += optind;
193 debug("after getopt\n");
194
195 /* We loosen up a bit and accept both "baudrate tty" and "tty baudrate" */
196 G.tty_name = argv[0];
197 ts = argv[1]; /* baud rate(s) */
198 if (isdigit(argv[0][0])) {
199 /* A number first, assume it's a speed (BSD style) */
200 G.tty_name = ts; /* tty name is in argv[1] */
201 ts = argv[0]; /* baud rate(s) */
202 }
203 parse_speeds(ts);
204
205 if (argv[2])
206 xsetenv("TERM", argv[2]);
207
208 debug("exiting parse_args\n");
209 }
210
211 /* set up tty as standard input, output, error */
open_tty(void)212 static void open_tty(void)
213 {
214 /* Set up new standard input, unless we are given an already opened port */
215 if (NOT_LONE_DASH(G.tty_name)) {
216 if (G.tty_name[0] != '/')
217 G.tty_name = xasprintf("/dev/%s", G.tty_name); /* will leak it */
218
219 /* Open the tty as standard input */
220 debug("open(2)\n");
221 close(0);
222 xopen(G.tty_name, O_RDWR | O_NONBLOCK); /* uses fd 0 */
223
224 /* Set proper protections and ownership */
225 fchown(0, 0, 0); /* 0:0 */
226 fchmod(0, 0620); /* crw--w---- */
227 } else {
228 char *n;
229 /*
230 * Standard input should already be connected to an open port.
231 * Make sure it is open for read/write.
232 */
233 if ((fcntl(0, F_GETFL) & (O_RDWR|O_RDONLY|O_WRONLY)) != O_RDWR)
234 bb_error_msg_and_die("stdin is not open for read/write");
235
236 /* Try to get real tty name instead of "-" */
237 n = xmalloc_ttyname(0);
238 if (n)
239 G.tty_name = n;
240 }
241 applet_name = xasprintf("getty: %s", skip_dev_pfx(G.tty_name));
242 }
243
set_tty_attrs(void)244 static void set_tty_attrs(void)
245 {
246 if (tcsetattr_stdin_TCSANOW(&G.tty_attrs) < 0)
247 bb_perror_msg_and_die("tcsetattr");
248 }
249
250 /* We manipulate tty_attrs this way:
251 * - first, we read existing tty_attrs
252 * - init_tty_attrs modifies some parts and sets it
253 * - auto_baud and/or BREAK processing can set different speed and set tty attrs
254 * - finalize_tty_attrs again modifies some parts and sets tty attrs before
255 * execing login
256 */
init_tty_attrs(int speed)257 static void init_tty_attrs(int speed)
258 {
259 /* Try to drain output buffer, with 5 sec timeout.
260 * Added on request from users of ~600 baud serial interface
261 * with biggish buffer on a 90MHz CPU.
262 * They were losing hundreds of bytes of buffered output
263 * on tcflush.
264 */
265 signal_no_SA_RESTART_empty_mask(SIGALRM, record_signo);
266 alarm(5);
267 tcdrain(STDIN_FILENO);
268 alarm(0);
269
270 /* Flush input and output queues, important for modems! */
271 tcflush(STDIN_FILENO, TCIOFLUSH);
272
273 /* Set speed if it wasn't specified as "0" on command line */
274 if (speed != B0)
275 cfsetspeed(&G.tty_attrs, speed);
276
277 /* Initial settings: 8-bit characters, raw mode, blocking i/o.
278 * Special characters are set after we have read the login name; all
279 * reads will be done in raw mode anyway.
280 */
281 /* Clear all bits except: */
282 G.tty_attrs.c_cflag &= (0
283 /* 2 stop bits (1 otherwise)
284 * Enable parity bit (both on input and output)
285 * Odd parity (else even)
286 */
287 | CSTOPB | PARENB | PARODD
288 #ifdef CMSPAR
289 | CMSPAR /* mark or space parity */
290 #endif
291 #ifdef CBAUD
292 | CBAUD /* (output) baud rate */
293 #endif
294 #ifdef CBAUDEX
295 | CBAUDEX /* (output) baud rate */
296 #endif
297 #ifdef CIBAUD
298 | CIBAUD /* input baud rate */
299 #endif
300 );
301 /* Set: 8 bits; hang up (drop DTR) on last close; enable receive */
302 G.tty_attrs.c_cflag |= CS8 | HUPCL | CREAD;
303 if (option_mask32 & F_LOCAL) {
304 /* ignore Carrier Detect pin:
305 * opens don't block when CD is low,
306 * losing CD doesn't hang up processes whose ctty is this tty
307 */
308 G.tty_attrs.c_cflag |= CLOCAL;
309 }
310 #ifdef CRTSCTS
311 if (option_mask32 & F_RTSCTS)
312 G.tty_attrs.c_cflag |= CRTSCTS; /* flow control using RTS/CTS pins */
313 #endif
314 G.tty_attrs.c_iflag = 0;
315 G.tty_attrs.c_lflag = 0;
316 /* non-raw output; add CR to each NL */
317 G.tty_attrs.c_oflag = OPOST | ONLCR;
318
319 /* reads would block only if < 1 char is available */
320 G.tty_attrs.c_cc[VMIN] = 1;
321 /* no timeout (reads block forever) */
322 G.tty_attrs.c_cc[VTIME] = 0;
323 #ifdef __linux__
324 G.tty_attrs.c_line = 0;
325 #endif
326
327 set_tty_attrs();
328
329 debug("term_io 2\n");
330 }
331
finalize_tty_attrs(void)332 static void finalize_tty_attrs(void)
333 {
334 /* software flow control on output (stop sending if XOFF is recvd);
335 * and on input (send XOFF when buffer is full)
336 */
337 G.tty_attrs.c_iflag |= IXON | IXOFF;
338 if (G.eol == '\r') {
339 G.tty_attrs.c_iflag |= ICRNL; /* map CR on input to NL */
340 }
341 /* Other bits in c_iflag:
342 * IXANY Any recvd char enables output (any char is also a XON)
343 * INPCK Enable parity check
344 * IGNPAR Ignore parity errors (drop bad bytes)
345 * PARMRK Mark parity errors with 0xff, 0x00 prefix
346 * (else bad byte is received as 0x00)
347 * ISTRIP Strip parity bit
348 * IGNBRK Ignore break condition
349 * BRKINT Send SIGINT on break - maybe set this?
350 * INLCR Map NL to CR
351 * IGNCR Ignore CR
352 * ICRNL Map CR to NL
353 * IUCLC Map uppercase to lowercase
354 * IMAXBEL Echo BEL on input line too long
355 * IUTF8 Appears to affect tty's idea of char widths,
356 * observed to improve backspacing through Unicode chars
357 */
358
359 /* ICANON line buffered input (NL or EOL or EOF chars end a line);
360 * ISIG recognize INT/QUIT/SUSP chars;
361 * ECHO echo input chars;
362 * ECHOE echo BS-SP-BS on erase character;
363 * ECHOK echo kill char specially, not as ^c (ECHOKE controls how exactly);
364 * ECHOKE erase all input via BS-SP-BS on kill char (else go to next line)
365 * ECHOCTL Echo ctrl chars as ^c (else echo verbatim:
366 * e.g. up arrow emits "ESC-something" and thus moves cursor up!)
367 */
368 G.tty_attrs.c_lflag |= ICANON | ISIG | ECHO | ECHOE | ECHOK | ECHOKE | ECHOCTL;
369 /* Other bits in c_lflag:
370 * XCASE Map uppercase to \lowercase [tried, doesn't work]
371 * ECHONL Echo NL even if ECHO is not set
372 * ECHOPRT On erase, echo erased chars
373 * [qwe<BS><BS><BS> input looks like "qwe\ewq/" on screen]
374 * NOFLSH Don't flush input buffer after interrupt or quit chars
375 * IEXTEN Enable extended functions (??)
376 * [glibc says it enables c_cc[LNEXT] "enter literal char"
377 * and c_cc[VDISCARD] "toggle discard buffered output" chars]
378 * FLUSHO Output being flushed (c_cc[VDISCARD] is in effect)
379 * PENDIN Retype pending input at next read or input char
380 * (c_cc[VREPRINT] is being processed)
381 * TOSTOP Send SIGTTOU for background output
382 * (why "stty sane" unsets this bit?)
383 */
384
385 G.tty_attrs.c_cc[VINTR] = CTL('C');
386 G.tty_attrs.c_cc[VQUIT] = CTL('\\');
387 G.tty_attrs.c_cc[VEOF] = CTL('D');
388 G.tty_attrs.c_cc[VEOL] = '\n';
389 #ifdef VSWTC
390 G.tty_attrs.c_cc[VSWTC] = 0;
391 #endif
392 #ifdef VSWTCH
393 G.tty_attrs.c_cc[VSWTCH] = 0;
394 #endif
395 G.tty_attrs.c_cc[VKILL] = CTL('U');
396 /* Other control chars:
397 * VEOL2
398 * VERASE, VWERASE - (word) erase. we may set VERASE in get_logname
399 * VREPRINT - reprint current input buffer
400 * VLNEXT, VDISCARD, VSTATUS
401 * VSUSP, VDSUSP - send (delayed) SIGTSTP
402 * VSTART, VSTOP - chars used for IXON/IXOFF
403 */
404
405 set_tty_attrs();
406
407 /* Now the newline character should be properly written */
408 full_write(STDOUT_FILENO, "\n", 1);
409 }
410
411 /* extract baud rate from modem status message */
auto_baud(void)412 static void auto_baud(void)
413 {
414 int nread;
415
416 /*
417 * This works only if the modem produces its status code AFTER raising
418 * the DCD line, and if the computer is fast enough to set the proper
419 * baud rate before the message has gone by. We expect a message of the
420 * following format:
421 *
422 * <junk><number><junk>
423 *
424 * The number is interpreted as the baud rate of the incoming call. If the
425 * modem does not tell us the baud rate within one second, we will keep
426 * using the current baud rate. It is advisable to enable BREAK
427 * processing (comma-separated list of baud rates) if the processing of
428 * modem status messages is enabled.
429 */
430
431 G.tty_attrs.c_cc[VMIN] = 0; /* don't block reads (min read is 0 chars) */
432 set_tty_attrs();
433
434 /*
435 * Wait for a while, then read everything the modem has said so far and
436 * try to extract the speed of the dial-in call.
437 */
438 sleep(1);
439 nread = safe_read(STDIN_FILENO, G.line_buf, sizeof(G.line_buf) - 1);
440 if (nread > 0) {
441 int speed;
442 char *bp;
443 G.line_buf[nread] = '\0';
444 for (bp = G.line_buf; bp < G.line_buf + nread; bp++) {
445 if (isdigit(*bp)) {
446 speed = bcode(bp);
447 if (speed > 0)
448 cfsetspeed(&G.tty_attrs, speed);
449 break;
450 }
451 }
452 }
453
454 /* Restore terminal settings */
455 G.tty_attrs.c_cc[VMIN] = 1; /* restore to value set by init_tty_attrs */
456 set_tty_attrs();
457 }
458
459 /* get user name, establish parity, speed, erase, kill, eol;
460 * return NULL on BREAK, logname on success
461 */
get_logname(void)462 static char *get_logname(void)
463 {
464 char *bp;
465 char c;
466
467 /* Flush pending input (esp. after parsing or switching the baud rate) */
468 usleep(100*1000); /* 0.1 sec */
469 tcflush(STDIN_FILENO, TCIFLUSH);
470
471 /* Prompt for and read a login name */
472 do {
473 /* Write issue file and prompt */
474 #ifdef ISSUE
475 if (!(option_mask32 & F_NOISSUE))
476 print_login_issue(G.issue, G.tty_name);
477 #endif
478 print_login_prompt();
479
480 /* Read name, watch for break, erase, kill, end-of-line */
481 bp = G.line_buf;
482 while (1) {
483 /* Do not report trivial EINTR/EIO errors */
484 errno = EINTR; /* make read of 0 bytes be silent too */
485 if (read(STDIN_FILENO, &c, 1) < 1) {
486 finalize_tty_attrs();
487 if (errno == EINTR || errno == EIO)
488 exit(EXIT_SUCCESS);
489 bb_perror_msg_and_die(bb_msg_read_error);
490 }
491
492 switch (c) {
493 case '\r':
494 case '\n':
495 *bp = '\0';
496 G.eol = c;
497 goto got_logname;
498 case CTL('H'):
499 case 0x7f:
500 G.tty_attrs.c_cc[VERASE] = c;
501 if (bp > G.line_buf) {
502 full_write(STDOUT_FILENO, "\010 \010", 3);
503 bp--;
504 }
505 break;
506 case CTL('U'):
507 while (bp > G.line_buf) {
508 full_write(STDOUT_FILENO, "\010 \010", 3);
509 bp--;
510 }
511 break;
512 case CTL('C'):
513 case CTL('D'):
514 finalize_tty_attrs();
515 exit(EXIT_SUCCESS);
516 case '\0':
517 /* BREAK. If we have speeds to try,
518 * return NULL (will switch speeds and return here) */
519 if (G.numspeed > 1)
520 return NULL;
521 /* fall through and ignore it */
522 default:
523 if ((unsigned char)c < ' ') {
524 /* ignore garbage characters */
525 } else if ((int)(bp - G.line_buf) < sizeof(G.line_buf) - 1) {
526 /* echo and store the character */
527 full_write(STDOUT_FILENO, &c, 1);
528 *bp++ = c;
529 }
530 break;
531 }
532 } /* end of get char loop */
533 got_logname: ;
534 } while (G.line_buf[0] == '\0'); /* while logname is empty */
535
536 return G.line_buf;
537 }
538
alarm_handler(int sig UNUSED_PARAM)539 static void alarm_handler(int sig UNUSED_PARAM)
540 {
541 finalize_tty_attrs();
542 _exit(EXIT_SUCCESS);
543 }
544
sleep10(void)545 static void sleep10(void)
546 {
547 sleep(10);
548 }
549
550 int getty_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
getty_main(int argc UNUSED_PARAM,char ** argv)551 int getty_main(int argc UNUSED_PARAM, char **argv)
552 {
553 int n;
554 pid_t pid, tsid;
555 char *logname;
556
557 INIT_G();
558 G.login = _PATH_LOGIN; /* default login program */
559 #ifdef ISSUE
560 G.issue = ISSUE; /* default issue file */
561 #endif
562 G.eol = '\r';
563
564 /* Parse command-line arguments */
565 parse_args(argv);
566
567 /* Create new session and pgrp, lose controlling tty */
568 pid = setsid(); /* this also gives us our pid :) */
569 if (pid < 0) {
570 int fd;
571 /* :(
572 * docs/ctty.htm says:
573 * "This is allowed only when the current process
574 * is not a process group leader".
575 * Thus, setsid() will fail if we _already_ are
576 * a session leader - which is quite possible for getty!
577 */
578 pid = getpid();
579 if (getsid(0) != pid) {
580 //for debugging:
581 //bb_perror_msg_and_die("setsid failed:"
582 // " pid %d ppid %d"
583 // " sid %d pgid %d",
584 // pid, getppid(),
585 // getsid(0), getpgid(0));
586 bb_perror_msg_and_die("setsid");
587 /*
588 * When we can end up here?
589 * Example: setsid() fails when run alone in interactive shell:
590 * # getty 115200 /dev/tty2
591 * because shell's child (getty) is put in a new process group.
592 * But doesn't fail if shell is not interactive
593 * (and therefore doesn't create process groups for pipes),
594 * or if getty is not the first process in the process group:
595 * # true | getty 115200 /dev/tty2
596 */
597 }
598 /* Looks like we are already a session leader.
599 * In this case (setsid failed) we may still have ctty,
600 * and it may be different from tty we need to control!
601 * If we still have ctty, on Linux ioctl(TIOCSCTTY)
602 * (which we are going to use a bit later) always fails -
603 * even if we try to take ctty which is already ours!
604 * Try to drop old ctty now to prevent that.
605 * Use O_NONBLOCK: old ctty may be a serial line.
606 */
607 fd = open("/dev/tty", O_RDWR | O_NONBLOCK);
608 if (fd >= 0) {
609 /* TIOCNOTTY sends SIGHUP to the foreground
610 * process group - which may include us!
611 * Make sure to not die on it:
612 */
613 sighandler_t old = signal(SIGHUP, SIG_IGN);
614 ioctl(fd, TIOCNOTTY);
615 close(fd);
616 signal(SIGHUP, old);
617 }
618 }
619
620 /* Close stdio, and stray descriptors, just in case */
621 n = xopen(bb_dev_null, O_RDWR);
622 /* dup2(n, 0); - no, we need to handle "getty - 9600" too */
623 xdup2(n, 1);
624 xdup2(n, 2);
625 while (n > 2)
626 close(n--);
627
628 /* Logging. We want special flavor of error_msg_and_die */
629 die_func = sleep10;
630 msg_eol = "\r\n";
631 /* most likely will internally use fd #3 in CLOEXEC mode: */
632 openlog(applet_name, LOG_PID, LOG_AUTH);
633 logmode = LOGMODE_BOTH;
634
635 #ifdef DEBUGGING
636 dbf = xfopen_for_write(DEBUGTERM);
637 for (n = 1; argv[n]; n++) {
638 debug(argv[n]);
639 debug("\n");
640 }
641 #endif
642
643 /* Open the tty as standard input, if it is not "-" */
644 debug("calling open_tty\n");
645 open_tty();
646 ndelay_off(STDIN_FILENO);
647 debug("duping\n");
648 xdup2(STDIN_FILENO, 1);
649 xdup2(STDIN_FILENO, 2);
650
651 /* Steal ctty if we don't have it yet */
652 tsid = tcgetsid(STDIN_FILENO);
653 if (tsid < 0 || pid != tsid) {
654 if (ioctl(STDIN_FILENO, TIOCSCTTY, /*force:*/ (long)1) < 0)
655 bb_perror_msg_and_die("TIOCSCTTY");
656 }
657
658 #ifdef __linux__
659 /* Make ourself a foreground process group within our session */
660 if (tcsetpgrp(STDIN_FILENO, pid) < 0)
661 bb_perror_msg_and_die("tcsetpgrp");
662 #endif
663
664 /*
665 * The following ioctl will fail if stdin is not a tty, but also when
666 * there is noise on the modem control lines. In the latter case, the
667 * common course of action is (1) fix your cables (2) give the modem more
668 * time to properly reset after hanging up. SunOS users can achieve (2)
669 * by patching the SunOS kernel variable "zsadtrlow" to a larger value;
670 * 5 seconds seems to be a good value.
671 */
672 if (tcgetattr(STDIN_FILENO, &G.tty_attrs) < 0)
673 bb_perror_msg_and_die("tcgetattr");
674
675 /* Update the utmp file. This tty is ours now! */
676 update_utmp(pid, LOGIN_PROCESS, G.tty_name, "LOGIN", G.fakehost);
677
678 /* Initialize tty attrs (raw mode, eight-bit, blocking i/o) */
679 debug("calling init_tty_attrs\n");
680 init_tty_attrs(G.speeds[0]);
681
682 /* Write the modem init string and DON'T flush the buffers */
683 if (option_mask32 & F_INITSTRING) {
684 debug("writing init string\n");
685 full_write1_str(G.initstring);
686 }
687
688 /* Optionally detect the baud rate from the modem status message */
689 debug("before autobaud\n");
690 if (option_mask32 & F_PARSE)
691 auto_baud();
692
693 /* Set the optional timer */
694 signal(SIGALRM, alarm_handler);
695 alarm(G.timeout); /* if 0, alarm is not set */
696
697 /* Optionally wait for CR or LF before writing /etc/issue */
698 if (option_mask32 & F_WAITCRLF) {
699 char ch;
700 debug("waiting for cr-lf\n");
701 while (safe_read(STDIN_FILENO, &ch, 1) == 1) {
702 debug("read %x\n", (unsigned char)ch);
703 if (ch == '\n' || ch == '\r')
704 break;
705 }
706 }
707
708 logname = NULL;
709 if (!(option_mask32 & F_NOPROMPT)) {
710 /* NB: init_tty_attrs already set line speed
711 * to G.speeds[0] */
712 int baud_index = 0;
713
714 while (1) {
715 /* Read the login name */
716 debug("reading login name\n");
717 logname = get_logname();
718 if (logname)
719 break;
720 /* We are here only if G.numspeed > 1 */
721 baud_index = (baud_index + 1) % G.numspeed;
722 cfsetspeed(&G.tty_attrs, G.speeds[baud_index]);
723 set_tty_attrs();
724 }
725 }
726
727 /* Disable timer */
728 alarm(0);
729
730 finalize_tty_attrs();
731
732 /* Let the login program take care of password validation */
733 /* We use PATH because we trust that root doesn't set "bad" PATH,
734 * and getty is not suid-root applet */
735 /* With -n, logname == NULL, and login will ask for username instead */
736 BB_EXECLP(G.login, G.login, "--", logname, (char *)0);
737 bb_error_msg_and_die("can't execute '%s'", G.login);
738 }
739