summaryrefslogtreecommitdiff
path: root/init/init.c
blob: b0443d09588b6d6eae8f6465bc90b921392973ef (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
/* vi: set sw=4 ts=4: */
/*
 * Mini init implementation for busybox
 *
 * Copyright (C) 1995, 1996 by Bruce Perens <bruce@pixar.com>.
 * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
 * Adjusted by so many folks, it's impossible to keep track.
 *
 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
 */

/* Turn this on to disable all the dangerous
   rebooting stuff when debugging.
#define DEBUG_INIT
*/

#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <paths.h>
#include <signal.h>
#include <stdarg.h>
#include <string.h>
#include <termios.h>
#include <unistd.h>
#include <limits.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <sys/reboot.h>
#include "busybox.h"

#include "init_shared.h"


#ifdef CONFIG_SYSLOGD
# include <sys/syslog.h>
#endif


#ifdef CONFIG_SELINUX
# include <selinux/selinux.h>
#endif /* CONFIG_SELINUX */


#define INIT_BUFFS_SIZE 256

/* From <linux/vt.h> */
struct vt_stat {
	unsigned short v_active;	/* active vt */
	unsigned short v_signal;	/* signal to send */
	unsigned short v_state;	/* vt bitmask */
};
enum { VT_GETSTATE = 0x5603 };	/* get global vt state info */

/* From <linux/serial.h> */
struct serial_struct {
	int	type;
	int	line;
	unsigned int	port;
	int	irq;
	int	flags;
	int	xmit_fifo_size;
	int	custom_divisor;
	int	baud_base;
	unsigned short	close_delay;
	char	io_type;
	char	reserved_char[1];
	int	hub6;
	unsigned short	closing_wait; /* time to wait before closing */
	unsigned short	closing_wait2; /* no longer used... */
	unsigned char	*iomem_base;
	unsigned short	iomem_reg_shift;
	unsigned int	port_high;
	unsigned long	iomap_base;	/* cookie passed into ioremap */
	int	reserved[1];
};


#ifndef _PATH_STDPATH
#define _PATH_STDPATH	"/usr/bin:/bin:/usr/sbin:/sbin"
#endif

#if defined CONFIG_FEATURE_INIT_COREDUMPS
/*
 * When a file named CORE_ENABLE_FLAG_FILE exists, setrlimit is called
 * before processes are spawned to set core file size as unlimited.
 * This is for debugging only.  Don't use this is production, unless
 * you want core dumps lying about....
 */
#define CORE_ENABLE_FLAG_FILE "/.init_enable_core"
#include <sys/resource.h>
#include <sys/time.h>
#endif

#define KERNEL_VERSION(a,b,c) (((a) << 16) + ((b) << 8) + (c))

#define INITTAB      "/etc/inittab"	/* inittab file location */
#ifndef INIT_SCRIPT
#define INIT_SCRIPT  "/etc/init.d/rcS"	/* Default sysinit script. */
#endif

#define MAXENV	16		/* Number of env. vars */

#define CONSOLE_BUFF_SIZE 32

/* Allowed init action types */
#define SYSINIT     0x001
#define RESPAWN     0x002
#define ASKFIRST    0x004
#define WAIT        0x008
#define ONCE        0x010
#define CTRLALTDEL  0x020
#define SHUTDOWN    0x040
#define RESTART     0x080

/* A mapping between "inittab" action name strings and action type codes. */
struct init_action_type {
	const char *name;
	int action;
};

static const struct init_action_type actions[] = {
	{"sysinit", SYSINIT},
	{"respawn", RESPAWN},
	{"askfirst", ASKFIRST},
	{"wait", WAIT},
	{"once", ONCE},
	{"ctrlaltdel", CTRLALTDEL},
	{"shutdown", SHUTDOWN},
	{"restart", RESTART},
	{0, 0}
};

/* Set up a linked list of init_actions, to be read from inittab */
struct init_action {
	pid_t pid;
	char command[INIT_BUFFS_SIZE];
	char terminal[CONSOLE_BUFF_SIZE];
	struct init_action *next;
	int action;
};

/* Static variables */
static struct init_action *init_action_list = NULL;
static char console[CONSOLE_BUFF_SIZE] = _PATH_CONSOLE;

#ifndef CONFIG_SYSLOGD
static char *log_console = VC_5;
#endif
static sig_atomic_t got_cont = 0;

enum {
	LOG = 0x1,
	CONSOLE = 0x2,

#if defined CONFIG_FEATURE_EXTRA_QUIET
	MAYBE_CONSOLE = 0x0,
#else
	MAYBE_CONSOLE = CONSOLE,
#endif

#ifndef RB_HALT_SYSTEM
	RB_HALT_SYSTEM = 0xcdef0123,
	RB_ENABLE_CAD = 0x89abcdef,
	RB_DISABLE_CAD = 0,
	RB_POWER_OFF = 0x4321fedc,
	RB_AUTOBOOT = 0x01234567,
#endif
};

static const char * const environment[] = {
	"HOME=/",
	"PATH=" _PATH_STDPATH,
	"SHELL=/bin/sh",
	"USER=root",
	NULL
};

/* Function prototypes */
static void delete_init_action(struct init_action *a);
static int waitfor(const struct init_action *a);
static void halt_signal(int sig);


static void loop_forever(void)
{
	while (1)
		sleep(1);
}

/* Print a message to the specified device.
 * Device may be bitwise-or'd from LOG | CONSOLE */
#ifndef DEBUG_INIT
static inline void messageD(int ATTRIBUTE_UNUSED device, 
				const char ATTRIBUTE_UNUSED *fmt, ...)
{
}
#else
#define messageD message
#endif
static void message(int device, const char *fmt, ...)
	__attribute__ ((format(printf, 2, 3)));
static void message(int device, const char *fmt, ...)
{
	va_list arguments;
	int l;
	char msg[1024];
#ifndef CONFIG_SYSLOGD
	static int log_fd = -1;
#endif

	msg[0] = '\r';
		va_start(arguments, fmt);
	l = vsnprintf(msg + 1, sizeof(msg) - 2, fmt, arguments) + 1;
		va_end(arguments);

#ifdef CONFIG_SYSLOGD
	/* Log the message to syslogd */
	if (device & LOG) {
		/* don`t out "\r\n" */
		openlog(bb_applet_name, 0, LOG_DAEMON);
		syslog(LOG_INFO, "%s", msg + 1);
		closelog();
	}

	msg[l++] = '\n';
	msg[l] = 0;
#else

	msg[l++] = '\n';
	msg[l] = 0;
	/* Take full control of the log tty, and never close it.
	 * It's mine, all mine!  Muhahahaha! */
	if (log_fd < 0) {
		if ((log_fd = device_open(log_console, O_RDWR | O_NONBLOCK | O_NOCTTY)) < 0) {
			log_fd = -2;
			bb_error_msg("Bummer, can't write to log on %s!", log_console);
			device = CONSOLE;
		} else {
			fcntl(log_fd, F_SETFD, FD_CLOEXEC);
		}
	}
	if ((device & LOG) && (log_fd >= 0)) {
		bb_full_write(log_fd, msg, l);
	}
#endif

	if (device & CONSOLE) {
		int fd = device_open(_PATH_CONSOLE,
					O_WRONLY | O_NOCTTY | O_NONBLOCK);
		/* Always send console messages to /dev/console so people will see them. */
		if (fd >= 0) {
			bb_full_write(fd, msg, l);
			close(fd);
#ifdef DEBUG_INIT
		/* all descriptors may be closed */
		} else {
			bb_error_msg("Bummer, can't print: ");
			va_start(arguments, fmt);
			vfprintf(stderr, fmt, arguments);
			va_end(arguments);
#endif
		}
	}
}

/* Set terminal settings to reasonable defaults */
static void set_term(int fd)
{
	struct termios tty;

	tcgetattr(fd, &tty);

	/* set control chars */
	tty.c_cc[VINTR] = 3;	/* C-c */
	tty.c_cc[VQUIT] = 28;	/* C-\ */
	tty.c_cc[VERASE] = 127;	/* C-? */
	tty.c_cc[VKILL] = 21;	/* C-u */
	tty.c_cc[VEOF] = 4;	/* C-d */
	tty.c_cc[VSTART] = 17;	/* C-q */
	tty.c_cc[VSTOP] = 19;	/* C-s */
	tty.c_cc[VSUSP] = 26;	/* C-z */

	/* use line dicipline 0 */
	tty.c_line = 0;

	/* Make it be sane */
	tty.c_cflag &= CBAUD | CBAUDEX | CSIZE | CSTOPB | PARENB | PARODD;
	tty.c_cflag |= CREAD | HUPCL | CLOCAL;


	/* input modes */
	tty.c_iflag = ICRNL | IXON | IXOFF;

	/* output modes */
	tty.c_oflag = OPOST | ONLCR;

	/* local modes */
	tty.c_lflag =
		ISIG | ICANON | ECHO | ECHOE | ECHOK | ECHOCTL | ECHOKE | IEXTEN;

	tcsetattr(fd, TCSANOW, &tty);
}

static void console_init(void)
{
	int fd;
	int tried = 0;
	struct vt_stat vt;
	struct serial_struct sr;
	char *s;

	if ((s = getenv("CONSOLE")) != NULL || (s = getenv("console")) != NULL) {
		safe_strncpy(console, s, sizeof(console));
#if #cpu(sparc)
	/* sparc kernel supports console=tty[ab] parameter which is also
	 * passed to init, so catch it here */
		/* remap tty[ab] to /dev/ttyS[01] */
		if (strcmp(s, "ttya") == 0)
			safe_strncpy(console, SC_0, sizeof(console));
		else if (strcmp(s, "ttyb") == 0)
			safe_strncpy(console, SC_1, sizeof(console));
#endif
	} else {
		/* 2.2 kernels: identify the real console backend and try to use it */
		if (ioctl(0, TIOCGSERIAL, &sr) == 0) {
			/* this is a serial console */
			snprintf(console, sizeof(console) - 1, SC_FORMAT, sr.line);
		} else if (ioctl(0, VT_GETSTATE, &vt) == 0) {
			/* this is linux virtual tty */
			snprintf(console, sizeof(console) - 1, VC_FORMAT, vt.v_active);
		} else {
			safe_strncpy(console, _PATH_CONSOLE, sizeof(console));
			tried++;
		}
	}

	while ((fd = open(console, O_RDONLY | O_NONBLOCK)) < 0 && tried < 2) {
		/* Can't open selected console -- try
			logical system console and VT_MASTER */
		safe_strncpy(console, (tried == 0 ? _PATH_CONSOLE : CURRENT_VC),
							sizeof(console));
		tried++;
	}
	if (fd < 0) {
		/* Perhaps we should panic here? */
#ifndef CONFIG_SYSLOGD
		log_console =
#endif
		safe_strncpy(console, bb_dev_null, sizeof(console));
	} else {
		s = getenv("TERM");
		/* check for serial console */
		if (ioctl(fd, TIOCGSERIAL, &sr) == 0) {
			/* Force the TERM setting to vt102 for serial console --
			 * if TERM is set to linux (the default) */
			if (s == NULL || strcmp(s, "linux") == 0)
				putenv("TERM=vt102");
#ifndef CONFIG_SYSLOGD
			log_console = console;
#endif
		} else {
			if (s == NULL)
				putenv("TERM=linux");
		}
		close(fd);
	}
	messageD(LOG, "console=%s", console);
}

static void fixup_argv(int argc, char **argv, char *new_argv0)
{
	int len;

	/* Fix up argv[0] to be certain we claim to be init */
	len = strlen(argv[0]);
	memset(argv[0], 0, len);
	safe_strncpy(argv[0], new_argv0, len + 1);

	/* Wipe argv[1]-argv[N] so they don't clutter the ps listing */
	len = 1;
	while (argc > len) {
		memset(argv[len], 0, strlen(argv[len]));
		len++;
	}
}

static pid_t run(const struct init_action *a)
{
	int i, junk;
	pid_t pid;
	char *s, *tmpCmd, *cmd[INIT_BUFFS_SIZE], *cmdpath;
	char buf[INIT_BUFFS_SIZE + 6];	/* INIT_BUFFS_SIZE+strlen("exec ")+1 */
	sigset_t nmask, omask;
	static const char press_enter[] =
#ifdef CUSTOMIZED_BANNER
#include CUSTOMIZED_BANNER
#endif
		"\nPlease press Enter to activate this console. ";

	/* Block sigchild while forking.  */
	sigemptyset(&nmask);
	sigaddset(&nmask, SIGCHLD);
	sigprocmask(SIG_BLOCK, &nmask, &omask);

	if ((pid = fork()) == 0) {
		struct stat sb;

		/* Clean up */
		close(0);
		close(1);
		close(2);
		sigprocmask(SIG_SETMASK, &omask, NULL);

		/* Reset signal handlers that were set by the parent process */
		signal(SIGUSR1, SIG_DFL);
		signal(SIGUSR2, SIG_DFL);
		signal(SIGINT, SIG_DFL);
		signal(SIGTERM, SIG_DFL);
		signal(SIGHUP, SIG_DFL);
		signal(SIGQUIT, SIG_DFL);
		signal(SIGCONT, SIG_DFL);
		signal(SIGSTOP, SIG_DFL);
		signal(SIGTSTP, SIG_DFL);

		/* Create a new session and make ourself the process
		 * group leader */
		setsid();

		/* Open the new terminal device */
		if ((device_open(a->terminal, O_RDWR)) < 0) {
			if (stat(a->terminal, &sb) != 0) {
				message(LOG | CONSOLE, "device '%s' does not exist.", a->terminal);
			} else {
				message(LOG | CONSOLE, "Bummer, can't open %s", a->terminal);
			}
			_exit(1);
		}

		/* Make sure the terminal will act fairly normal for us */
		set_term(0);
		/* Setup stdout, stderr for the new process so
		 * they point to the supplied terminal */
		dup(0);
		dup(0);

		/* If the init Action requires us to wait, then force the
		 * supplied terminal to be the controlling tty. */
		if (a->action & (SYSINIT | WAIT | CTRLALTDEL | SHUTDOWN | RESTART)) {
			pid_t pgrp, tmp_pid;

			/* Now fork off another process to just hang around */
			if ((pid = fork()) < 0) {
				message(LOG | CONSOLE, "Can't fork!");
				_exit(1);
			}

			if (pid > 0) {

				/* We are the parent -- wait till the child is done */
				signal(SIGINT, SIG_IGN);
				signal(SIGTSTP, SIG_IGN);
				signal(SIGQUIT, SIG_IGN);
				signal(SIGCHLD, SIG_DFL);

				/* Wait for child to exit */
				while ((tmp_pid = waitpid(pid, &junk, 0)) != pid) {
					if (tmp_pid == -1 && errno == ECHILD) {
						break;
					}
					/* FIXME handle other errors */
				}

				/* See if stealing the controlling tty back is necessary */
				pgrp = tcgetpgrp(0);
				if (pgrp != getpid())
					_exit(0);

				/* Use a temporary process to steal the controlling tty. */
				if ((pid = fork()) < 0) {
					message(LOG | CONSOLE, "Can't fork!");
					_exit(1);
				}
				if (pid == 0) {
					setsid();
					ioctl(0, TIOCSCTTY, 1);
					_exit(0);
				}
				while ((tmp_pid = waitpid(pid, &junk, 0)) != pid) {
					if (tmp_pid < 0 && errno == ECHILD)
						break;
				}
				_exit(0);
			}

			/* Now fall though to actually execute things */
		}

		/* See if any special /bin/sh requiring characters are present */
		if (strpbrk(a->command, "~`!$^&*()=|\\{}[];\"'<>?") != NULL) {
			cmd[0] = (char *)DEFAULT_SHELL;
			cmd[1] = "-c";
			cmd[2] = strcat(strcpy(buf, "exec "), a->command);
			cmd[3] = NULL;
		} else {
			/* Convert command (char*) into cmd (char**, one word per string) */
			strcpy(buf, a->command);
			s = buf;
			for (tmpCmd = buf, i = 0; (tmpCmd = strsep(&s, " \t")) != NULL;) {
				if (*tmpCmd != '\0') {
					cmd[i] = tmpCmd;
					i++;
				}
			}
			cmd[i] = NULL;
		}

		cmdpath = cmd[0];

		/*
		   Interactive shells want to see a dash in argv[0].  This
		   typically is handled by login, argv will be setup this
		   way if a dash appears at the front of the command path
		   (like "-/bin/sh").
		 */

		if (*cmdpath == '-') {

			/* skip over the dash */
			++cmdpath;

			/* find the last component in the command pathname */
			s = bb_get_last_path_component(cmdpath);

			/* make a new argv[0] */
			if ((cmd[0] = malloc(strlen(s) + 2)) == NULL) {
				message(LOG | CONSOLE, bb_msg_memory_exhausted);
				cmd[0] = cmdpath;
			} else {
				cmd[0][0] = '-';
				strcpy(cmd[0] + 1, s);
			}
#ifdef CONFIG_FEATURE_INIT_SCTTY
			/* Establish this process as session leader and
			 * (attempt) to make the tty (if any) a controlling tty.
			 */
			(void) setsid();
			(void) ioctl(0, TIOCSCTTY, 0/*don't steal it*/);
#endif
		}

#if !defined(__UCLIBC__) || defined(__ARCH_HAS_MMU__)
		if (a->action & ASKFIRST) {
			char c;
			/*
			 * Save memory by not exec-ing anything large (like a shell)
			 * before the user wants it. This is critical if swap is not
			 * enabled and the system has low memory. Generally this will
			 * be run on the second virtual console, and the first will
			 * be allowed to start a shell or whatever an init script
			 * specifies.
			 */
			messageD(LOG, "Waiting for enter to start '%s'"
						"(pid %d, terminal %s)\n",
					  cmdpath, getpid(), a->terminal);
			bb_full_write(1, press_enter, sizeof(press_enter) - 1);
			while(read(0, &c, 1) == 1 && c != '\n')
				;
		}
#endif

		/* Log the process name and args */
		message(LOG, "Starting pid %d, console %s: '%s'",
				  getpid(), a->terminal, cmdpath);

#if defined CONFIG_FEATURE_INIT_COREDUMPS
		if (stat(CORE_ENABLE_FLAG_FILE, &sb) == 0) {
			struct rlimit limit;

			limit.rlim_cur = RLIM_INFINITY;
			limit.rlim_max = RLIM_INFINITY;
			setrlimit(RLIMIT_CORE, &limit);
		}
#endif

		/* Now run it.  The new program will take over this PID,
		 * so nothing further in init.c should be run. */
		execv(cmdpath, cmd);

		/* We're still here?  Some error happened. */
		message(LOG | CONSOLE, "Bummer, could not run '%s': %m", cmdpath);
		_exit(-1);
	}
	sigprocmask(SIG_SETMASK, &omask, NULL);
	return pid;
}

static int waitfor(const struct init_action *a)
{
	int pid;
	int status, wpid;

	pid = run(a);
	while (1) {
		wpid = waitpid(pid,&status,0);
		if (wpid == pid)
			break;
		if (wpid == -1 && errno == ECHILD) {
			/* we missed its termination */
			break;
		}
		/* FIXME other errors should maybe trigger an error, but allow
		 * the program to continue */
	}
	return wpid;
}

/* Run all commands of a particular type */
static void run_actions(int action)
{
	struct init_action *a, *tmp;

	for (a = init_action_list; a; a = tmp) {
		tmp = a->next;
		if (a->action == action) {
			if (access(a->terminal, R_OK | W_OK)) {
				delete_init_action(a);
			} else if (a->action & (SYSINIT | WAIT | CTRLALTDEL | SHUTDOWN | RESTART)) {
				waitfor(a);
				delete_init_action(a);
			} else if (a->action & ONCE) {
				run(a);
				delete_init_action(a);
			} else if (a->action & (RESPAWN | ASKFIRST)) {
				/* Only run stuff with pid==0.  If they have
				 * a pid, that means it is still running */
				if (a->pid == 0) {
					a->pid = run(a);
				}
			}
		}
	}
}

#ifndef DEBUG_INIT
static void init_reboot(unsigned long magic)
{
	pid_t pid;
	/* We have to fork here, since the kernel calls do_exit(0) in
	 * linux/kernel/sys.c, which can cause the machine to panic when
	 * the init process is killed.... */
	if ((pid = fork()) == 0) {
		reboot(magic);
		_exit(0);
	}
	waitpid (pid, NULL, 0);
}

static void shutdown_system(void)
{
	sigset_t block_signals;

	/* run everything to be run at "shutdown".  This is done _prior_
	 * to killing everything, in case people wish to use scripts to
	 * shut things down gracefully... */
	run_actions(SHUTDOWN);

	/* first disable all our signals */
	sigemptyset(&block_signals);
	sigaddset(&block_signals, SIGHUP);
	sigaddset(&block_signals, SIGQUIT);
	sigaddset(&block_signals, SIGCHLD);
	sigaddset(&block_signals, SIGUSR1);
	sigaddset(&block_signals, SIGUSR2);
	sigaddset(&block_signals, SIGINT);
	sigaddset(&block_signals, SIGTERM);
	sigaddset(&block_signals, SIGCONT);
	sigaddset(&block_signals, SIGSTOP);
	sigaddset(&block_signals, SIGTSTP);
	sigprocmask(SIG_BLOCK, &block_signals, NULL);

	/* Allow Ctrl-Alt-Del to reboot system. */
	init_reboot(RB_ENABLE_CAD);

	message(CONSOLE | LOG, "The system is going down NOW !!");
	sync();

	/* Send signals to every process _except_ pid 1 */
	message(CONSOLE | LOG, "Sending SIGTERM to all processes.");
	kill(-1, SIGTERM);
	sleep(1);
	sync();

	message(CONSOLE | LOG, "Sending SIGKILL to all processes.");
	kill(-1, SIGKILL);
	sleep(1);

	sync();
}

static void exec_signal(int sig ATTRIBUTE_UNUSED)
{
	struct init_action *a, *tmp;
	sigset_t unblock_signals;

	for (a = init_action_list; a; a = tmp) {
		tmp = a->next;
		if (a->action & RESTART) {
			shutdown_system();

			/* unblock all signals, blocked in shutdown_system() */
			sigemptyset(&unblock_signals);
			sigaddset(&unblock_signals, SIGHUP);
			sigaddset(&unblock_signals, SIGQUIT);
			sigaddset(&unblock_signals, SIGCHLD);
			sigaddset(&unblock_signals, SIGUSR1);
			sigaddset(&unblock_signals, SIGUSR2);
			sigaddset(&unblock_signals, SIGINT);
			sigaddset(&unblock_signals, SIGTERM);
			sigaddset(&unblock_signals, SIGCONT);
			sigaddset(&unblock_signals, SIGSTOP);
			sigaddset(&unblock_signals, SIGTSTP);
			sigprocmask(SIG_UNBLOCK, &unblock_signals, NULL);

			/* Close whatever files are open. */
			close(0);
			close(1);
			close(2);

			/* Open the new terminal device */
			if ((device_open(a->terminal, O_RDWR)) < 0) {
				struct stat sb;
				if (stat(a->terminal, &sb) != 0) {
					message(LOG | CONSOLE, "device '%s' does not exist.", a->terminal);
				} else {
					message(LOG | CONSOLE, "Bummer, can't open %s", a->terminal);
				}
				halt_signal(SIGUSR1);
			}

			/* Make sure the terminal will act fairly normal for us */
			set_term(0);
			/* Setup stdout, stderr on the supplied terminal */
			dup(0);
			dup(0);

			messageD(CONSOLE | LOG, "Trying to re-exec %s", a->command);
			execl(a->command, a->command, NULL);

			message(CONSOLE | LOG, "exec of '%s' failed: %m",
					a->command);
			sync();
			sleep(2);
			init_reboot(RB_HALT_SYSTEM);
			loop_forever();
		}
	}
}

static void halt_signal(int sig ATTRIBUTE_UNUSED)
{
	shutdown_system();
	message(CONSOLE | LOG, "The system is halted.");
	sync();

	/* allow time for last message to reach serial console */
	sleep(2);

	if (sig == SIGUSR2)
		init_reboot(RB_POWER_OFF);
	else
		init_reboot(RB_HALT_SYSTEM);

	loop_forever();
}

static void reboot_signal(int sig ATTRIBUTE_UNUSED)
{
	shutdown_system();
	message(CONSOLE | LOG, "Please stand by while rebooting the system.");
	sync();

	/* allow time for last message to reach serial console */
	sleep(2);

	init_reboot(RB_AUTOBOOT);

	loop_forever();
}

static void ctrlaltdel_signal(int sig ATTRIBUTE_UNUSED)
{
	run_actions(CTRLALTDEL);
}

/* The SIGSTOP & SIGTSTP handler */
static void stop_handler(int sig ATTRIBUTE_UNUSED)
{
	int saved_errno = errno;

	got_cont = 0;
	while (!got_cont)
		pause();
	got_cont = 0;
	errno = saved_errno;
}

/* The SIGCONT handler */
static void cont_handler(int sig ATTRIBUTE_UNUSED)
{
	got_cont = 1;
}

#endif							/* ! DEBUG_INIT */

static void new_init_action(int action, const char *command, const char *cons)
{
	struct init_action *new_action, *a, *last;

	if (*cons == '\0')
		cons = console;

	if (strcmp(cons, bb_dev_null) == 0 && (action & ASKFIRST))
		return;

	new_action = calloc((size_t) (1), sizeof(struct init_action));
	if (!new_action) {
		message(LOG | CONSOLE, "Memory allocation failure");
		loop_forever();
	}

	/* Append to the end of the list */
	for (a = last = init_action_list; a; a = a->next) {
		/* don't enter action if it's already in the list,
		 * but do overwrite existing actions */
		if ((strcmp(a->command, command) == 0) &&
		    (strcmp(a->terminal, cons) ==0)) {
			a->action = action;
			free(new_action);
			return;
		}
		last = a;
	}
	if (last) {
		last->next = new_action;
	} else {
		init_action_list = new_action;
	}
	strcpy(new_action->command, command);
	new_action->action = action;
	strcpy(new_action->terminal, cons);
#if 0   /* calloc zeroed always */
	new_action->pid = 0;
#endif
	messageD(LOG|CONSOLE, "command='%s' action='%d' terminal='%s'\n",
		new_action->command, new_action->action, new_action->terminal);
}

static void delete_init_action(struct init_action *action)
{
	struct init_action *a, *b = NULL;

	for (a = init_action_list; a; b = a, a = a->next) {
		if (a == action) {
			if (b == NULL) {
				init_action_list = a->next;
			} else {
				b->next = a->next;
			}
			free(a);
			break;
		}
	}
}

/* NOTE that if CONFIG_FEATURE_USE_INITTAB is NOT defined,
 * then parse_inittab() simply adds in some default
 * actions(i.e., runs INIT_SCRIPT and then starts a pair
 * of "askfirst" shells).  If CONFIG_FEATURE_USE_INITTAB
 * _is_ defined, but /etc/inittab is missing, this
 * results in the same set of default behaviors.
 */
static void parse_inittab(void)
{
#ifdef CONFIG_FEATURE_USE_INITTAB
	FILE *file;
	char buf[INIT_BUFFS_SIZE], lineAsRead[INIT_BUFFS_SIZE];
	char tmpConsole[CONSOLE_BUFF_SIZE];
	char *id, *runlev, *action, *command, *eol;
	const struct init_action_type *a = actions;


	file = fopen(INITTAB, "r");
	if (file == NULL) {
		/* No inittab file -- set up some default behavior */
#endif
		/* Reboot on Ctrl-Alt-Del */
		new_init_action(CTRLALTDEL, "/sbin/reboot", "");
		/* Umount all filesystems on halt/reboot */
		new_init_action(SHUTDOWN, "/bin/umount -a -r", "");
		/* Swapoff on halt/reboot */
		if(ENABLE_SWAPONOFF) new_init_action(SHUTDOWN, "/sbin/swapoff -a", "");
		/* Prepare to restart init when a HUP is received */
		new_init_action(RESTART, "/sbin/init", "");
		/* Askfirst shell on tty1-4 */
		new_init_action(ASKFIRST, bb_default_login_shell, "");
		new_init_action(ASKFIRST, bb_default_login_shell, VC_2);
		new_init_action(ASKFIRST, bb_default_login_shell, VC_3);
		new_init_action(ASKFIRST, bb_default_login_shell, VC_4);
		/* sysinit */
		new_init_action(SYSINIT, INIT_SCRIPT, "");

		return;
#ifdef CONFIG_FEATURE_USE_INITTAB
	}

	while (fgets(buf, INIT_BUFFS_SIZE, file) != NULL) {
		/* Skip leading spaces */
		for (id = buf; *id == ' ' || *id == '\t'; id++);

		/* Skip the line if it's a comment */
		if (*id == '#' || *id == '\n')
			continue;

		/* Trim the trailing \n */
		eol = strrchr(id, '\n');
		if (eol != NULL)
			*eol = '\0';

		/* Keep a copy around for posterity's sake (and error msgs) */
		strcpy(lineAsRead, buf);

		/* Separate the ID field from the runlevels */
		runlev = strchr(id, ':');
		if (runlev == NULL || *(runlev + 1) == '\0') {
			message(LOG | CONSOLE, "Bad inittab entry: %s", lineAsRead);
			continue;
		} else {
			*runlev = '\0';
			++runlev;
		}

		/* Separate the runlevels from the action */
		action = strchr(runlev, ':');
		if (action == NULL || *(action + 1) == '\0') {
			message(LOG | CONSOLE, "Bad inittab entry: %s", lineAsRead);
			continue;
		} else {
			*action = '\0';
			++action;
		}

		/* Separate the action from the command */
		command = strchr(action, ':');
		if (command == NULL || *(command + 1) == '\0') {
			message(LOG | CONSOLE, "Bad inittab entry: %s", lineAsRead);
			continue;
		} else {
			*command = '\0';
			++command;
		}

		/* Ok, now process it */
		for (a = actions; a->name != 0; a++) {
			if (strcmp(a->name, action) == 0) {
				if (*id != '\0') {
					if(strncmp(id, "/dev/", 5) == 0)
						id += 5;
					strcpy(tmpConsole, "/dev/");
					safe_strncpy(tmpConsole + 5, id,
						CONSOLE_BUFF_SIZE - 5);
					id = tmpConsole;
				}
				new_init_action(a->action, command, id);
				break;
			}
		}
		if (a->name == 0) {
			/* Choke on an unknown action */
			message(LOG | CONSOLE, "Bad inittab entry: %s", lineAsRead);
		}
	}
	fclose(file);
	return;
#endif							/* CONFIG_FEATURE_USE_INITTAB */
}

#ifdef CONFIG_FEATURE_USE_INITTAB
static void reload_signal(int sig ATTRIBUTE_UNUSED)
{
	struct init_action *a, *tmp;

	message(LOG, "Reloading /etc/inittab");

	/* disable old entrys */
	for (a = init_action_list; a; a = a->next ) {
		a->action = ONCE;
	}

	parse_inittab();

	/* remove unused entrys */
	for (a = init_action_list; a; a = tmp) {
		tmp = a->next;
		if (a->action & (ONCE | SYSINIT | WAIT ) &&
				a->pid == 0 ) {
			delete_init_action(a);
		}
	}
	run_actions(RESPAWN);
	return;
}
#endif							/* CONFIG_FEATURE_USE_INITTAB */

int init_main(int argc, char **argv)
{
	struct init_action *a;
	pid_t wpid;
	int status;

	if (argc > 1 && !strcmp(argv[1], "-q")) {
		return kill(1,SIGHUP);
	}
#ifndef DEBUG_INIT
	/* Expect to be invoked as init with PID=1 or be invoked as linuxrc */
	if (getpid() != 1 &&
		(!ENABLE_FEATURE_INITRD || !strstr(bb_applet_name, "linuxrc")))
	{
		bb_show_usage();
	}
	/* Set up sig handlers  -- be sure to
	 * clear all of these in run() */
	signal(SIGHUP, exec_signal);
	signal(SIGQUIT, exec_signal);
	signal(SIGUSR1, halt_signal);
	signal(SIGUSR2, halt_signal);
	signal(SIGINT, ctrlaltdel_signal);
	signal(SIGTERM, reboot_signal);
	signal(SIGCONT, cont_handler);
	signal(SIGSTOP, stop_handler);
	signal(SIGTSTP, stop_handler);

	/* Turn off rebooting via CTL-ALT-DEL -- we get a
	 * SIGINT on CAD so we can shut things down gracefully... */
	init_reboot(RB_DISABLE_CAD);
#endif

	/* Figure out where the default console should be */
	console_init();

	/* Close whatever files are open, and reset the console. */
	close(0);
	close(1);
	close(2);

	if (device_open(console, O_RDWR | O_NOCTTY) == 0) {
		set_term(0);
		close(0);
	}

	chdir("/");
	setsid();
	{
		const char * const *e;
		/* Make sure environs is set to something sane */
		for(e = environment; *e; e++)
			putenv((char *) *e);
	}
	/* Hello world */
	message(MAYBE_CONSOLE | LOG, "init started:  %s", bb_msg_full_version);

	/* Make sure there is enough memory to do something useful. */
	if (ENABLE_SWAPONOFF) {
		struct sysinfo info;

		if (!sysinfo(&info) &&
			(info.mem_unit ? : 1) * (long long)info.totalram < MEGABYTE)
		{
			message(CONSOLE,"Low memory: forcing swapon.");
			/* swapon -a requires /proc typically */
			new_init_action(SYSINIT, "/bin/mount -t proc proc /proc", "");
			/* Try to turn on swap */
			new_init_action(SYSINIT, "/sbin/swapon -a", "");
			run_actions(SYSINIT);   /* wait and removing */
		}
	}

	/* Check if we are supposed to be in single user mode */
	if (argc > 1 && (!strcmp(argv[1], "single") ||
					 !strcmp(argv[1], "-s") || !strcmp(argv[1], "1"))) {
		/* Start a shell on console */
		new_init_action(RESPAWN, bb_default_login_shell, "");
	} else {
		/* Not in single user mode -- see what inittab says */

		/* NOTE that if CONFIG_FEATURE_USE_INITTAB is NOT defined,
		 * then parse_inittab() simply adds in some default
		 * actions(i.e., runs INIT_SCRIPT and then starts a pair
		 * of "askfirst" shells */
		parse_inittab();
	}

#ifdef CONFIG_SELINUX
	if (getenv("SELINUX_INIT") == NULL) {
		int enforce = 0;

		putenv("SELINUX_INIT=YES");
		if (selinux_init_load_policy(&enforce) == 0) {
			execv(argv[0], argv);
		} else if (enforce > 0) {
			/* SELinux in enforcing mode but load_policy failed */
			/* At this point, we probably can't open /dev/console, so log() won't work */
			message(CONSOLE,"Unable to load SELinux Policy. Machine is in enforcing mode. Halting now.");
			exit(1);
		}
	}
#endif /* CONFIG_SELINUX */

	/* Make the command line just say "init"  -- thats all, nothing else */
	fixup_argv(argc, argv, "init");

	/* Now run everything that needs to be run */

	/* First run the sysinit command */
	run_actions(SYSINIT);

	/* Next run anything that wants to block */
	run_actions(WAIT);

	/* Next run anything to be run only once */
	run_actions(ONCE);

#ifdef CONFIG_FEATURE_USE_INITTAB
	/* Redefine SIGHUP to reread /etc/inittab */
	signal(SIGHUP, reload_signal);
#else
	signal(SIGHUP, SIG_IGN);
#endif /* CONFIG_FEATURE_USE_INITTAB */


	/* Now run the looping stuff for the rest of forever */
	while (1) {
		/* run the respawn stuff */
		run_actions(RESPAWN);

		/* run the askfirst stuff */
		run_actions(ASKFIRST);

		/* Don't consume all CPU time -- sleep a bit */
		sleep(1);

		/* Wait for a child process to exit */
		wpid = wait(&status);
		while (wpid > 0) {
			/* Find out who died and clean up their corpse */
			for (a = init_action_list; a; a = a->next) {
				if (a->pid == wpid) {
					/* Set the pid to 0 so that the process gets
					 * restarted by run_actions() */
					a->pid = 0;
					message(LOG, "Process '%s' (pid %d) exited.  "
							"Scheduling it for restart.",
							a->command, wpid);
				}
			}
			/* see if anyone else is waiting to be reaped */
			wpid = waitpid (-1, &status, WNOHANG);
		}
	}
}