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-rw-r--r--init.c1045
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diff --git a/init.c b/init.c
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1/* vi: set sw=4 ts=4: */
2/*
3 * Mini init implementation for busybox
4 *
5 *
6 * Copyright (C) 1995, 1996 by Bruce Perens <bruce@pixar.com>.
7 * Adjusted by so many folks, it's impossible to keep track.
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License as published by
11 * the Free Software Foundation; either version 2 of the License, or
12 * (at your option) any later version.
13 *
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 * General Public License for more details.
18 *
19 * You should have received a copy of the GNU General Public License
20 * along with this program; if not, write to the Free Software
21 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
22 *
23 */
24
25/* Turn this on to disable all the dangerous
26 rebooting stuff when debugging.
27#define DEBUG_INIT
28*/
29
30#include <stdio.h>
31#include <stdlib.h>
32#include <errno.h>
33#include <paths.h>
34#include <signal.h>
35#include <stdarg.h>
36#include <string.h>
37#include <termios.h>
38#include <unistd.h>
39#include <limits.h>
40#include <sys/fcntl.h>
41#include <sys/ioctl.h>
42#include <sys/mount.h>
43#include <sys/types.h>
44#include <sys/wait.h>
45#include "busybox.h"
46#ifdef BB_SYSLOGD
47# include <sys/syslog.h>
48#endif
49
50
51/* From <linux/vt.h> */
52struct vt_stat {
53 unsigned short v_active; /* active vt */
54 unsigned short v_signal; /* signal to send */
55 unsigned short v_state; /* vt bitmask */
56};
57static const int VT_GETSTATE = 0x5603; /* get global vt state info */
58
59/* From <linux/serial.h> */
60struct serial_struct {
61 int type;
62 int line;
63 int port;
64 int irq;
65 int flags;
66 int xmit_fifo_size;
67 int custom_divisor;
68 int baud_base;
69 unsigned short close_delay;
70 char reserved_char[2];
71 int hub6;
72 unsigned short closing_wait; /* time to wait before closing */
73 unsigned short closing_wait2; /* no longer used... */
74 int reserved[4];
75};
76
77
78
79#ifndef RB_HALT_SYSTEM
80static const int RB_HALT_SYSTEM = 0xcdef0123;
81static const int RB_ENABLE_CAD = 0x89abcdef;
82static const int RB_DISABLE_CAD = 0;
83#define RB_POWER_OFF 0x4321fedc
84static const int RB_AUTOBOOT = 0x01234567;
85#endif
86
87#if (__GNU_LIBRARY__ > 5) || defined(__dietlibc__)
88 #include <sys/reboot.h>
89 #define init_reboot(magic) reboot(magic)
90#else
91 #define init_reboot(magic) reboot(0xfee1dead, 672274793, magic)
92#endif
93
94#ifndef _PATH_STDPATH
95#define _PATH_STDPATH "/usr/bin:/bin:/usr/sbin:/sbin"
96#endif
97
98
99#if defined BB_FEATURE_INIT_COREDUMPS
100/*
101 * When a file named CORE_ENABLE_FLAG_FILE exists, setrlimit is called
102 * before processes are spawned to set core file size as unlimited.
103 * This is for debugging only. Don't use this is production, unless
104 * you want core dumps lying about....
105 */
106#define CORE_ENABLE_FLAG_FILE "/.init_enable_core"
107#include <sys/resource.h>
108#include <sys/time.h>
109#endif
110
111#define KERNEL_VERSION(a,b,c) (((a) << 16) + ((b) << 8) + (c))
112
113#if __GNU_LIBRARY__ > 5
114 #include <sys/kdaemon.h>
115#else
116 extern int bdflush (int func, long int data);
117#endif
118
119
120#define SHELL "/bin/sh" /* Default shell */
121#define LOGIN_SHELL "-" SHELL /* Default login shell */
122#define INITTAB "/etc/inittab" /* inittab file location */
123#ifndef INIT_SCRIPT
124#define INIT_SCRIPT "/etc/init.d/rcS" /* Default sysinit script. */
125#endif
126
127#define MAXENV 16 /* Number of env. vars */
128//static const int MAXENV = 16; /* Number of env. vars */
129static const int LOG = 0x1;
130static const int CONSOLE = 0x2;
131
132/* Allowed init action types */
133typedef enum {
134 SYSINIT = 1,
135 RESPAWN,
136 ASKFIRST,
137 WAIT,
138 ONCE,
139 CTRLALTDEL,
140 SHUTDOWN
141} initActionEnum;
142
143/* A mapping between "inittab" action name strings and action type codes. */
144typedef struct initActionType {
145 const char *name;
146 initActionEnum action;
147} initActionType;
148
149static const struct initActionType actions[] = {
150 {"sysinit", SYSINIT},
151 {"respawn", RESPAWN},
152 {"askfirst", ASKFIRST},
153 {"wait", WAIT},
154 {"once", ONCE},
155 {"ctrlaltdel", CTRLALTDEL},
156 {"shutdown", SHUTDOWN},
157 {0, 0}
158};
159
160/* Set up a linked list of initActions, to be read from inittab */
161typedef struct initActionTag initAction;
162struct initActionTag {
163 pid_t pid;
164 char process[256];
165 char console[256];
166 initAction *nextPtr;
167 initActionEnum action;
168};
169static initAction *initActionList = NULL;
170
171
172static char *secondConsole = VC_2;
173static char *thirdConsole = VC_3;
174static char *fourthConsole = VC_4;
175static char *log = VC_5;
176static int kernelVersion = 0;
177static char termType[32] = "TERM=linux";
178static char console[32] = _PATH_CONSOLE;
179
180static void delete_initAction(initAction * action);
181
182static void loop_forever(void)
183{
184 while (1)
185 sleep (1);
186}
187
188/* Print a message to the specified device.
189 * Device may be bitwise-or'd from LOG | CONSOLE */
190static void message(int device, char *fmt, ...)
191 __attribute__ ((format (printf, 2, 3)));
192static void message(int device, char *fmt, ...)
193{
194 va_list arguments;
195 int fd;
196
197#ifdef BB_SYSLOGD
198
199 /* Log the message to syslogd */
200 if (device & LOG) {
201 char msg[1024];
202
203 va_start(arguments, fmt);
204 vsnprintf(msg, sizeof(msg), fmt, arguments);
205 va_end(arguments);
206 syslog_msg(LOG_USER, LOG_USER|LOG_INFO, msg);
207 }
208#else
209 static int log_fd = -1;
210
211 /* Take full control of the log tty, and never close it.
212 * It's mine, all mine! Muhahahaha! */
213 if (log_fd < 0) {
214 if (log == NULL) {
215 /* don't even try to log, because there is no such console */
216 log_fd = -2;
217 /* log to main console instead */
218 device = CONSOLE;
219 } else if ((log_fd = device_open(log, O_RDWR|O_NDELAY)) < 0) {
220 log_fd = -2;
221 fprintf(stderr, "Bummer, can't write to log on %s!\r\n", log);
222 log = NULL;
223 device = CONSOLE;
224 }
225 }
226 if ((device & LOG) && (log_fd >= 0)) {
227 va_start(arguments, fmt);
228 vdprintf(log_fd, fmt, arguments);
229 va_end(arguments);
230 }
231#endif
232
233 if (device & CONSOLE) {
234 /* Always send console messages to /dev/console so people will see them. */
235 if (
236 (fd =
237 device_open(_PATH_CONSOLE,
238 O_WRONLY | O_NOCTTY | O_NDELAY)) >= 0) {
239 va_start(arguments, fmt);
240 vdprintf(fd, fmt, arguments);
241 va_end(arguments);
242 close(fd);
243 } else {
244 fprintf(stderr, "Bummer, can't print: ");
245 va_start(arguments, fmt);
246 vfprintf(stderr, fmt, arguments);
247 va_end(arguments);
248 }
249 }
250}
251
252/* Set terminal settings to reasonable defaults */
253static void set_term(int fd)
254{
255 struct termios tty;
256
257 tcgetattr(fd, &tty);
258
259 /* set control chars */
260 tty.c_cc[VINTR] = 3; /* C-c */
261 tty.c_cc[VQUIT] = 28; /* C-\ */
262 tty.c_cc[VERASE] = 127; /* C-? */
263 tty.c_cc[VKILL] = 21; /* C-u */
264 tty.c_cc[VEOF] = 4; /* C-d */
265 tty.c_cc[VSTART] = 17; /* C-q */
266 tty.c_cc[VSTOP] = 19; /* C-s */
267 tty.c_cc[VSUSP] = 26; /* C-z */
268
269 /* use line dicipline 0 */
270 tty.c_line = 0;
271
272 /* Make it be sane */
273 tty.c_cflag &= CBAUD|CBAUDEX|CSIZE|CSTOPB|PARENB|PARODD;
274 tty.c_cflag |= CREAD|HUPCL|CLOCAL;
275
276
277 /* input modes */
278 tty.c_iflag = ICRNL | IXON | IXOFF;
279
280 /* output modes */
281 tty.c_oflag = OPOST | ONLCR;
282
283 /* local modes */
284 tty.c_lflag =
285 ISIG | ICANON | ECHO | ECHOE | ECHOK | ECHOCTL | ECHOKE | IEXTEN;
286
287 tcsetattr(fd, TCSANOW, &tty);
288}
289
290/* How much memory does this machine have?
291 Units are kBytes to avoid overflow on 4GB machines */
292static int check_free_memory(void)
293{
294 struct sysinfo info;
295 unsigned int result, u, s=10;
296
297 if (sysinfo(&info) != 0) {
298 perror_msg("Error checking free memory");
299 return -1;
300 }
301
302 /* Kernels 2.0.x and 2.2.x return info.mem_unit==0 with values in bytes.
303 * Kernels 2.4.0 return info.mem_unit in bytes. */
304 u = info.mem_unit;
305 if (u==0) u=1;
306 while ( (u&1) == 0 && s > 0 ) { u>>=1; s--; }
307 result = (info.totalram>>s) + (info.totalswap>>s);
308 result = result*u;
309 if (result < 0) result = INT_MAX;
310 return result;
311}
312
313static void console_init(void)
314{
315 int fd;
316 int tried_devcons = 0;
317 int tried_vtprimary = 0;
318 struct vt_stat vt;
319 struct serial_struct sr;
320 char *s;
321
322 if ((s = getenv("TERM")) != NULL) {
323 snprintf(termType, sizeof(termType) - 1, "TERM=%s", s);
324 }
325
326 if ((s = getenv("CONSOLE")) != NULL) {
327 safe_strncpy(console, s, sizeof(console));
328 }
329#if #cpu(sparc)
330 /* sparc kernel supports console=tty[ab] parameter which is also
331 * passed to init, so catch it here */
332 else if ((s = getenv("console")) != NULL) {
333 /* remap tty[ab] to /dev/ttyS[01] */
334 if (strcmp(s, "ttya") == 0)
335 safe_strncpy(console, SC_0, sizeof(console));
336 else if (strcmp(s, "ttyb") == 0)
337 safe_strncpy(console, SC_1, sizeof(console));
338 }
339#endif
340 else {
341 /* 2.2 kernels: identify the real console backend and try to use it */
342 if (ioctl(0, TIOCGSERIAL, &sr) == 0) {
343 /* this is a serial console */
344 snprintf(console, sizeof(console) - 1, SC_FORMAT, sr.line);
345 } else if (ioctl(0, VT_GETSTATE, &vt) == 0) {
346 /* this is linux virtual tty */
347 snprintf(console, sizeof(console) - 1, VC_FORMAT, vt.v_active);
348 } else {
349 safe_strncpy(console, _PATH_CONSOLE, sizeof(console));
350 tried_devcons++;
351 }
352 }
353
354 while ((fd = open(console, O_RDONLY | O_NONBLOCK)) < 0) {
355 /* Can't open selected console -- try /dev/console */
356 if (!tried_devcons) {
357 tried_devcons++;
358 safe_strncpy(console, _PATH_CONSOLE, sizeof(console));
359 continue;
360 }
361 /* Can't open selected console -- try vt1 */
362 if (!tried_vtprimary) {
363 tried_vtprimary++;
364 safe_strncpy(console, VC_1, sizeof(console));
365 continue;
366 }
367 break;
368 }
369 if (fd < 0) {
370 /* Perhaps we should panic here? */
371 safe_strncpy(console, "/dev/null", sizeof(console));
372 } else {
373 /* check for serial console and disable logging to tty5 & running a
374 * shell to tty2-4 */
375 if (ioctl(0, TIOCGSERIAL, &sr) == 0) {
376 log = NULL;
377 secondConsole = NULL;
378 thirdConsole = NULL;
379 fourthConsole = NULL;
380 /* Force the TERM setting to vt102 for serial console --
381 * iff TERM is set to linux (the default) */
382 if (strcmp( termType, "TERM=linux" ) == 0)
383 safe_strncpy(termType, "TERM=vt102", sizeof(termType));
384 message(LOG | CONSOLE,
385 "serial console detected. Disabling virtual terminals.\r\n");
386 }
387 close(fd);
388 }
389 message(LOG, "console=%s\n", console);
390}
391
392static void fixup_argv(int argc, char **argv, char *new_argv0)
393{
394 int len;
395 /* Fix up argv[0] to be certain we claim to be init */
396 len = strlen(argv[0]);
397 memset(argv[0], 0, len);
398 strncpy(argv[0], new_argv0, len);
399
400 /* Wipe argv[1]-argv[N] so they don't clutter the ps listing */
401 len = 1;
402 while (argc > len) {
403 memset(argv[len], 0, strlen(argv[len]));
404 len++;
405 }
406}
407
408
409static pid_t run(char *command, char *terminal, int get_enter)
410{
411 int i, j;
412 int fd;
413 pid_t pid;
414 char *tmpCmd, *s;
415 char *cmd[255], *cmdpath;
416 char buf[255];
417 struct stat sb;
418 static const char press_enter[] =
419
420#ifdef CUSTOMIZED_BANNER
421#include CUSTOMIZED_BANNER
422#endif
423
424 "\nPlease press Enter to activate this console. ";
425 char *environment[MAXENV+1] = {
426 termType,
427 "HOME=/",
428 "PATH=/usr/bin:/bin:/usr/sbin:/sbin",
429 "SHELL=" SHELL,
430 "USER=root",
431 NULL
432 };
433
434 /* inherit environment to the child, merging our values -andy */
435 for (i=0; environ[i]; i++) {
436 for (j=0; environment[j]; j++) {
437 s = strchr(environment[j], '=');
438 if (!strncmp(environ[i], environment[j], s - environment[j]))
439 break;
440 }
441 if (!environment[j]) {
442 environment[j++] = environ[i];
443 environment[j] = NULL;
444 }
445 }
446
447 if ((pid = fork()) == 0) {
448 /* Clean up */
449 ioctl(0, TIOCNOTTY, 0);
450 close(0);
451 close(1);
452 close(2);
453 setsid();
454
455 /* Reset signal handlers set for parent process */
456 signal(SIGUSR1, SIG_DFL);
457 signal(SIGUSR2, SIG_DFL);
458 signal(SIGINT, SIG_DFL);
459 signal(SIGTERM, SIG_DFL);
460 signal(SIGHUP, SIG_DFL);
461
462 if ((fd = device_open(terminal, O_RDWR)) < 0) {
463 if (stat(terminal, &sb) != 0) {
464 message(LOG | CONSOLE, "device '%s' does not exist.\n",
465 terminal);
466 exit(1);
467 }
468 message(LOG | CONSOLE, "Bummer, can't open %s\r\n", terminal);
469 exit(1);
470 }
471 dup2(fd, 0);
472 dup2(fd, 1);
473 dup2(fd, 2);
474 ioctl(0, TIOCSCTTY, 1);
475 tcsetpgrp(0, getpgrp());
476 set_term(0);
477
478 /* See if any special /bin/sh requiring characters are present */
479 if (strpbrk(command, "~`!$^&*()=|\\{}[];\"'<>?") != NULL) {
480 cmd[0] = SHELL;
481 cmd[1] = "-c";
482 strcpy(buf, "exec ");
483 strncat(buf, command, sizeof(buf) - strlen(buf) - 1);
484 cmd[2] = buf;
485 cmd[3] = NULL;
486 } else {
487 /* Convert command (char*) into cmd (char**, one word per string) */
488 for (tmpCmd = command, i = 0;
489 (tmpCmd = strsep(&command, " \t")) != NULL;) {
490 if (*tmpCmd != '\0') {
491 cmd[i] = tmpCmd;
492 tmpCmd++;
493 i++;
494 }
495 }
496 cmd[i] = NULL;
497 }
498
499 cmdpath = cmd[0];
500
501 /*
502 Interactive shells want to see a dash in argv[0]. This
503 typically is handled by login, argv will be setup this
504 way if a dash appears at the front of the command path
505 (like "-/bin/sh").
506 */
507
508 if (*cmdpath == '-') {
509
510 /* skip over the dash */
511 ++cmdpath;
512
513 /* find the last component in the command pathname */
514 s = get_last_path_component(cmdpath);
515
516 /* make a new argv[0] */
517 if ((cmd[0] = malloc(strlen(s)+2)) == NULL) {
518 message(LOG | CONSOLE, "malloc failed");
519 cmd[0] = cmdpath;
520 } else {
521 cmd[0][0] = '-';
522 strcpy(cmd[0]+1, s);
523 }
524 }
525
526 if (get_enter == TRUE) {
527 /*
528 * Save memory by not exec-ing anything large (like a shell)
529 * before the user wants it. This is critical if swap is not
530 * enabled and the system has low memory. Generally this will
531 * be run on the second virtual console, and the first will
532 * be allowed to start a shell or whatever an init script
533 * specifies.
534 */
535#ifdef DEBUG_INIT
536 message(LOG, "Waiting for enter to start '%s' (pid %d, console %s)\r\n",
537 cmd[0], getpid(), terminal);
538#endif
539 write(fileno(stdout), press_enter, sizeof(press_enter) - 1);
540 getc(stdin);
541 }
542
543#ifdef DEBUG_INIT
544 /* Log the process name and args */
545 message(LOG, "Starting pid %d, console %s: '%s'\r\n",
546 getpid(), terminal, command);
547#endif
548
549#if defined BB_FEATURE_INIT_COREDUMPS
550 if (stat (CORE_ENABLE_FLAG_FILE, &sb) == 0) {
551 struct rlimit limit;
552 limit.rlim_cur = RLIM_INFINITY;
553 limit.rlim_max = RLIM_INFINITY;
554 setrlimit(RLIMIT_CORE, &limit);
555 }
556#endif
557
558 /* Now run it. The new program will take over this PID,
559 * so nothing further in init.c should be run. */
560 execve(cmdpath, cmd, environment);
561
562 /* We're still here? Some error happened. */
563 message(LOG | CONSOLE, "Bummer, could not run '%s': %s\n", cmdpath,
564 strerror(errno));
565 exit(-1);
566 }
567 return pid;
568}
569
570static int waitfor(char *command, char *terminal, int get_enter)
571{
572 int status, wpid;
573 int pid = run(command, terminal, get_enter);
574
575 while (1) {
576 wpid = wait(&status);
577 if (wpid > 0 && wpid != pid) {
578 continue;
579 }
580 if (wpid == pid)
581 break;
582 }
583 return wpid;
584}
585
586/* Make sure there is enough memory to do something useful. *
587 * Calls "swapon -a" if needed so be sure /etc/fstab is present... */
588static void check_memory(void)
589{
590 struct stat statBuf;
591
592 if (check_free_memory() > 1000)
593 return;
594
595 if (stat("/etc/fstab", &statBuf) == 0) {
596 /* swapon -a requires /proc typically */
597 waitfor("mount proc /proc -t proc", console, FALSE);
598 /* Try to turn on swap */
599 waitfor("swapon -a", console, FALSE);
600 if (check_free_memory() < 1000)
601 goto goodnight;
602 } else
603 goto goodnight;
604 return;
605
606 goodnight:
607 message(CONSOLE,
608 "Sorry, your computer does not have enough memory.\r\n");
609 loop_forever();
610}
611
612/* Run all commands to be run right before halt/reboot */
613static void run_actions(initActionEnum action)
614{
615 initAction *a, *tmp;
616 for (a = initActionList; a; a = tmp) {
617 tmp = a->nextPtr;
618 if (a->action == action) {
619 waitfor(a->process, a->console, FALSE);
620 delete_initAction(a);
621 }
622 }
623}
624
625
626#ifndef DEBUG_INIT
627static void shutdown_system(void)
628{
629
630 /* first disable our SIGHUP signal */
631 signal(SIGHUP, SIG_DFL);
632
633 /* Allow Ctrl-Alt-Del to reboot system. */
634 init_reboot(RB_ENABLE_CAD);
635
636 message(CONSOLE|LOG, "\r\nThe system is going down NOW !!\r\n");
637 sync();
638
639 /* Send signals to every process _except_ pid 1 */
640 message(CONSOLE|LOG, "Sending SIGTERM to all processes.\r\n");
641 kill(-1, SIGTERM);
642 sleep(1);
643 sync();
644
645 message(CONSOLE|LOG, "Sending SIGKILL to all processes.\r\n");
646 kill(-1, SIGKILL);
647 sleep(1);
648
649 /* run everything to be run at "shutdown" */
650 run_actions(SHUTDOWN);
651
652 sync();
653 if (kernelVersion > 0 && kernelVersion <= KERNEL_VERSION(2,2,11)) {
654 /* bdflush, kupdate not needed for kernels >2.2.11 */
655 bdflush(1, 0);
656 sync();
657 }
658}
659
660static void halt_signal(int sig)
661{
662 shutdown_system();
663 message(CONSOLE|LOG,
664 "The system is halted. Press %s or turn off power\r\n",
665 (secondConsole == NULL) /* serial console */
666 ? "Reset" : "CTRL-ALT-DEL");
667 sync();
668
669 /* allow time for last message to reach serial console */
670 sleep(2);
671
672 if (sig == SIGUSR2 && kernelVersion >= KERNEL_VERSION(2,2,0))
673 init_reboot(RB_POWER_OFF);
674 else
675 init_reboot(RB_HALT_SYSTEM);
676
677 loop_forever();
678}
679
680static void reboot_signal(int sig)
681{
682 shutdown_system();
683 message(CONSOLE|LOG, "Please stand by while rebooting the system.\r\n");
684 sync();
685
686 /* allow time for last message to reach serial console */
687 sleep(2);
688
689 init_reboot(RB_AUTOBOOT);
690
691 loop_forever();
692}
693
694static void ctrlaltdel_signal(int sig)
695{
696 run_actions(CTRLALTDEL);
697}
698
699#endif /* ! DEBUG_INIT */
700
701static void new_initAction(initActionEnum action, char *process, char *cons)
702{
703 initAction *newAction;
704#ifdef BB_FEATURE_INIT_NORMAL_ORDER
705 initAction *a;
706#endif
707
708 if (*cons == '\0')
709 cons = console;
710
711 /* If BusyBox detects that a serial console is in use,
712 * then entries not refering to the console or null devices will _not_ be run.
713 * The exception to this rule is the null device.
714 */
715 if (secondConsole == NULL && strcmp(cons, console)
716 && strcmp(cons, "/dev/null"))
717 return;
718 if (strcmp(cons, "/dev/null") == 0 && action == ASKFIRST)
719 return;
720
721 newAction = calloc((size_t) (1), sizeof(initAction));
722 if (!newAction) {
723 message(LOG | CONSOLE, "Memory allocation failure\n");
724 loop_forever();
725 }
726#ifdef BB_FEATURE_INIT_NORMAL_ORDER
727 for (a = initActionList; a && a->nextPtr; a = a->nextPtr) ;
728 if (a) {
729 a->nextPtr = newAction;
730 } else {
731 initActionList = newAction;
732 }
733#else
734 newAction->nextPtr = initActionList;
735 initActionList = newAction;
736#endif
737 strncpy(newAction->process, process, 255);
738 newAction->action = action;
739 strncpy(newAction->console, cons, 255);
740 newAction->pid = 0;
741// message(LOG|CONSOLE, "process='%s' action='%d' console='%s'\n",
742// newAction->process, newAction->action, newAction->console);
743}
744
745static void delete_initAction(initAction * action)
746{
747 initAction *a, *b = NULL;
748
749 for (a = initActionList; a; b = a, a = a->nextPtr) {
750 if (a == action) {
751 if (b == NULL) {
752 initActionList = a->nextPtr;
753 } else {
754 b->nextPtr = a->nextPtr;
755 }
756 free(a);
757 break;
758 }
759 }
760}
761
762/* NOTE that if BB_FEATURE_USE_INITTAB is NOT defined,
763 * then parse_inittab() simply adds in some default
764 * actions(i.e., runs INIT_SCRIPT and then starts a pair
765 * of "askfirst" shells). If BB_FEATURE_USE_INITTAB
766 * _is_ defined, but /etc/inittab is missing, this
767 * results in the same set of default behaviors.
768 * */
769static void parse_inittab(void)
770{
771#ifdef BB_FEATURE_USE_INITTAB
772 FILE *file;
773 char buf[256], lineAsRead[256], tmpConsole[256];
774 char *id, *runlev, *action, *process, *eol;
775 const struct initActionType *a = actions;
776 int foundIt;
777
778
779 file = fopen(INITTAB, "r");
780 if (file == NULL) {
781 /* No inittab file -- set up some default behavior */
782#endif
783 /* Reboot on Ctrl-Alt-Del */
784 new_initAction(CTRLALTDEL, "/sbin/reboot", console);
785#ifdef BB_FEATURE_INIT_NORMAL_ORDER
786 /* Umount all filesystems on halt/reboot */
787 new_initAction(SHUTDOWN, "/bin/umount -a -r", console);
788 /* Swapoff on halt/reboot */
789 new_initAction(SHUTDOWN, "/sbin/swapoff -a", console);
790#else
791 /* Swapoff on halt/reboot */
792 new_initAction(SHUTDOWN, "/sbin/swapoff -a", console);
793 /* Umount all filesystems on halt/reboot */
794 new_initAction(SHUTDOWN, "/bin/umount -a -r", console);
795#endif
796 /* Askfirst shell on tty1 */
797 new_initAction(ASKFIRST, LOGIN_SHELL, console);
798 /* Askfirst shell on tty2 */
799 if (secondConsole != NULL)
800 new_initAction(ASKFIRST, LOGIN_SHELL, secondConsole);
801 /* Askfirst shell on tty3 */
802 if (thirdConsole != NULL)
803 new_initAction(ASKFIRST, LOGIN_SHELL, thirdConsole);
804 /* Askfirst shell on tty4 */
805 if (fourthConsole != NULL)
806 new_initAction(ASKFIRST, LOGIN_SHELL, fourthConsole);
807 /* sysinit */
808 new_initAction(SYSINIT, INIT_SCRIPT, console);
809
810 return;
811#ifdef BB_FEATURE_USE_INITTAB
812 }
813
814 while (fgets(buf, 255, file) != NULL) {
815 foundIt = FALSE;
816 /* Skip leading spaces */
817 for (id = buf; *id == ' ' || *id == '\t'; id++);
818
819 /* Skip the line if it's a comment */
820 if (*id == '#' || *id == '\n')
821 continue;
822
823 /* Trim the trailing \n */
824 eol = strrchr(id, '\n');
825 if (eol != NULL)
826 *eol = '\0';
827
828 /* Keep a copy around for posterity's sake (and error msgs) */
829 strcpy(lineAsRead, buf);
830
831 /* Separate the ID field from the runlevels */
832 runlev = strchr(id, ':');
833 if (runlev == NULL || *(runlev + 1) == '\0') {
834 message(LOG | CONSOLE, "Bad inittab entry: %s\n", lineAsRead);
835 continue;
836 } else {
837 *runlev = '\0';
838 ++runlev;
839 }
840
841 /* Separate the runlevels from the action */
842 action = strchr(runlev, ':');
843 if (action == NULL || *(action + 1) == '\0') {
844 message(LOG | CONSOLE, "Bad inittab entry: %s\n", lineAsRead);
845 continue;
846 } else {
847 *action = '\0';
848 ++action;
849 }
850
851 /* Separate the action from the process */
852 process = strchr(action, ':');
853 if (process == NULL || *(process + 1) == '\0') {
854 message(LOG | CONSOLE, "Bad inittab entry: %s\n", lineAsRead);
855 continue;
856 } else {
857 *process = '\0';
858 ++process;
859 }
860
861 /* Ok, now process it */
862 a = actions;
863 while (a->name != 0) {
864 if (strcmp(a->name, action) == 0) {
865 if (*id != '\0') {
866 strcpy(tmpConsole, "/dev/");
867 strncat(tmpConsole, id, 200);
868 id = tmpConsole;
869 }
870 new_initAction(a->action, process, id);
871 foundIt = TRUE;
872 }
873 a++;
874 }
875 if (foundIt == TRUE)
876 continue;
877 else {
878 /* Choke on an unknown action */
879 message(LOG | CONSOLE, "Bad inittab entry: %s\n", lineAsRead);
880 }
881 }
882 return;
883#endif /* BB_FEATURE_USE_INITTAB */
884}
885
886
887
888extern int init_main(int argc, char **argv)
889{
890 initAction *a, *tmp;
891 pid_t wpid;
892 int status;
893
894#ifndef DEBUG_INIT
895 /* Expect to be invoked as init with PID=1 or be invoked as linuxrc */
896 if (getpid() != 1
897#ifdef BB_FEATURE_LINUXRC
898 && strstr(applet_name, "linuxrc") == NULL
899#endif
900 )
901 {
902 show_usage();
903 }
904 /* Set up sig handlers -- be sure to
905 * clear all of these in run() */
906 signal(SIGUSR1, halt_signal);
907 signal(SIGUSR2, halt_signal);
908 signal(SIGINT, ctrlaltdel_signal);
909 signal(SIGTERM, reboot_signal);
910
911 /* Turn off rebooting via CTL-ALT-DEL -- we get a
912 * SIGINT on CAD so we can shut things down gracefully... */
913 init_reboot(RB_DISABLE_CAD);
914#endif
915
916 /* Figure out what kernel this is running */
917 kernelVersion = get_kernel_revision();
918
919 /* Figure out where the default console should be */
920 console_init();
921
922 /* Close whatever files are open, and reset the console. */
923 close(0);
924 close(1);
925 close(2);
926 set_term(0);
927 chdir("/");
928 setsid();
929
930 /* Make sure PATH is set to something sane */
931 putenv("PATH="_PATH_STDPATH);
932
933 /* Hello world */
934#ifndef DEBUG_INIT
935 message(
936#if ! defined BB_FEATURE_EXTRA_QUIET
937 CONSOLE|
938#endif
939 LOG,
940 "init started: %s\r\n", full_version);
941#else
942 message(
943#if ! defined BB_FEATURE_EXTRA_QUIET
944 CONSOLE|
945#endif
946 LOG,
947 "init(%d) started: %s\r\n", getpid(), full_version);
948#endif
949
950
951 /* Make sure there is enough memory to do something useful. */
952 check_memory();
953
954 /* Check if we are supposed to be in single user mode */
955 if (argc > 1 && (!strcmp(argv[1], "single") ||
956 !strcmp(argv[1], "-s") || !strcmp(argv[1], "1"))) {
957 /* Ask first then start a shell on tty2-4 */
958 if (secondConsole != NULL)
959 new_initAction(ASKFIRST, LOGIN_SHELL, secondConsole);
960 if (thirdConsole != NULL)
961 new_initAction(ASKFIRST, LOGIN_SHELL, thirdConsole);
962 if (fourthConsole != NULL)
963 new_initAction(ASKFIRST, LOGIN_SHELL, fourthConsole);
964 /* Start a shell on tty1 */
965 new_initAction(RESPAWN, LOGIN_SHELL, console);
966 } else {
967 /* Not in single user mode -- see what inittab says */
968
969 /* NOTE that if BB_FEATURE_USE_INITTAB is NOT defined,
970 * then parse_inittab() simply adds in some default
971 * actions(i.e., runs INIT_SCRIPT and then starts a pair
972 * of "askfirst" shells */
973 parse_inittab();
974 }
975
976 /* Make the command line just say "init" -- thats all, nothing else */
977 fixup_argv(argc, argv, "init");
978
979 /* Now run everything that needs to be run */
980
981 /* First run the sysinit command */
982 run_actions(SYSINIT);
983 /* Next run anything that wants to block */
984 run_actions(WAIT);
985 /* Next run anything to be run only once */
986 for (a = initActionList; a; a = tmp) {
987 tmp = a->nextPtr;
988 if (a->action == ONCE) {
989 run(a->process, a->console, FALSE);
990 /* Now remove the "once" entry from the list */
991 delete_initAction(a);
992 }
993 }
994 /* If there is nothing else to do, stop */
995 if (initActionList == NULL) {
996 message(LOG | CONSOLE,
997 "No more tasks for init -- sleeping forever.\n");
998 loop_forever();
999 }
1000
1001 /* Now run the looping stuff for the rest of forever */
1002 while (1) {
1003 for (a = initActionList; a; a = a->nextPtr) {
1004 /* Only run stuff with pid==0. If they have
1005 * a pid, that means they are still running */
1006 if (a->pid == 0) {
1007 switch (a->action) {
1008 case RESPAWN:
1009 /* run the respawn stuff */
1010 a->pid = run(a->process, a->console, FALSE);
1011 break;
1012 case ASKFIRST:
1013 /* run the askfirst stuff */
1014 a->pid = run(a->process, a->console, TRUE);
1015 break;
1016 /* silence the compiler's incessant whining */
1017 default:
1018 break;
1019 }
1020 }
1021 }
1022 /* Wait for a child process to exit */
1023 wpid = wait(&status);
1024 if (wpid > 0) {
1025 /* Find out who died and clean up their corpse */
1026 for (a = initActionList; a; a = a->nextPtr) {
1027 if (a->pid == wpid) {
1028 a->pid = 0;
1029 message(LOG,
1030 "Process '%s' (pid %d) exited. Scheduling it for restart.\n",
1031 a->process, wpid);
1032 }
1033 }
1034 }
1035 sleep(1);
1036 }
1037}
1038
1039/*
1040Local Variables:
1041c-file-style: "linux"
1042c-basic-offset: 4
1043tab-width: 4
1044End:
1045*/
generated by cgit v1.2.3-55-g6feb (git 2.39.1) at 2025-03-24 00:52:11 +0000