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