1 /* vi: set sw=4 ts=4: */
3 * Mini init implementation for busybox
5 * Copyright (C) 1995, 1996 by Bruce Perens <bruce@pixar.com>.
6 * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
7 * Adjusted by so many folks, it's impossible to keep track.
9 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
15 #include <sys/reboot.h>
16 #include <sys/resource.h>
20 /* Was a CONFIG_xxx option. A lot of people were building
21 * not fully functional init by switching it on! */
24 #define COMMAND_SIZE 256
25 #define CONSOLE_NAME_SIZE 32
27 /* Default sysinit script. */
29 #define INIT_SCRIPT "/etc/init.d/rcS"
32 /* Each type of actions can appear many times. They will be
33 * handled in order. RESTART is an exception, only 1st is used.
35 /* Start these actions first and wait for completion */
37 /* Start these after SYSINIT and wait for completion */
39 /* Start these after WAIT and *dont* wait for completion */
42 * NB: while SYSINIT/WAIT/ONCE are being processed,
43 * SIGHUP ("reread /etc/inittab") will be ignored.
44 * Rationale: it would be ambiguous whether SYSINIT/WAIT/ONCE
45 * need to be rerun or not.
47 /* Start these after ONCE are started, restart on exit */
49 /* Like RESPAWN, but wait for <Enter> to be pressed on tty */
52 * Start these on SIGINT, and wait for completion.
53 * Then go back to respawning RESPAWN and ASKFIRST actions.
54 * NB: kernel sends SIGINT to us if Ctrl-Alt-Del was pressed.
56 #define CTRLALTDEL 0x20
58 * Start these before killing all processes in preparation for
59 * running RESTART actions or doing low-level halt/reboot/poweroff
60 * (initiated by SIGUSR1/SIGTERM/SIGUSR2).
61 * Wait for completion before proceeding.
65 * exec() on SIGQUIT. SHUTDOWN actions are started and waited for,
66 * then all processes are killed, then init exec's 1st RESTART action,
67 * replacing itself by it. If no RESTART action specified,
68 * SIGQUIT has no effect.
73 /* A linked list of init_actions, to be read from inittab */
75 struct init_action
*next
;
78 char terminal
[CONSOLE_NAME_SIZE
];
79 char command
[COMMAND_SIZE
];
82 static struct init_action
*init_action_list
= NULL
;
84 static const char *log_console
= VC_5
;
89 MAYBE_CONSOLE
= L_CONSOLE
* !ENABLE_FEATURE_EXTRA_QUIET
,
90 #ifndef RB_HALT_SYSTEM
91 RB_HALT_SYSTEM
= 0xcdef0123, /* FIXME: this overflows enum */
92 RB_ENABLE_CAD
= 0x89abcdef,
94 RB_POWER_OFF
= 0x4321fedc,
95 RB_AUTOBOOT
= 0x01234567,
99 /* Print a message to the specified device.
100 * "where" may be bitwise-or'd from L_LOG | L_CONSOLE
101 * NB: careful, we can be called after vfork!
103 #define dbg_message(...) do { if (DEBUG_INIT) message(__VA_ARGS__); } while (0)
104 static void message(int where
, const char *fmt
, ...)
105 __attribute__ ((format(printf
, 2, 3)));
106 static void message(int where
, const char *fmt
, ...)
113 va_start(arguments
, fmt
);
114 l
= 1 + vsnprintf(msg
+ 1, sizeof(msg
) - 2, fmt
, arguments
);
115 if (l
> sizeof(msg
) - 1)
119 #if ENABLE_FEATURE_INIT_SYSLOG
122 /* Log the message to syslogd */
123 openlog("init", 0, LOG_DAEMON
);
124 /* don't print "\r" */
125 syslog(LOG_INFO
, "%s", msg
+ 1);
132 static int log_fd
= -1;
136 /* Take full control of the log tty, and never close it.
137 * It's mine, all mine! Muhahahaha! */
140 log_fd
= STDERR_FILENO
;
142 log_fd
= device_open(log_console
, O_WRONLY
| O_NONBLOCK
| O_NOCTTY
);
144 bb_error_msg("can't log to %s", log_console
);
147 close_on_exec_on(log_fd
);
152 full_write(log_fd
, msg
, l
);
153 if (log_fd
== STDERR_FILENO
)
154 return; /* don't print dup messages */
159 if (where
& L_CONSOLE
) {
160 /* Send console messages to console so people will see them. */
161 full_write(STDERR_FILENO
, msg
, l
);
165 static void console_init(void)
170 s
= getenv("CONSOLE");
172 s
= getenv("console");
174 int fd
= open(s
, O_RDWR
| O_NONBLOCK
| O_NOCTTY
);
176 dup2(fd
, STDIN_FILENO
);
177 dup2(fd
, STDOUT_FILENO
);
178 xmove_fd(fd
, STDERR_FILENO
);
180 dbg_message(L_LOG
, "console='%s'", s
);
182 /* Make sure fd 0,1,2 are not closed
183 * (so that they won't be used by future opens) */
185 // Users report problems
186 // /* Make sure init can't be blocked by writing to stderr */
187 // fcntl(STDERR_FILENO, F_SETFL, fcntl(STDERR_FILENO, F_GETFL) | O_NONBLOCK);
191 if (ioctl(STDIN_FILENO
, VT_OPENQRY
, &vtno
) != 0) {
192 /* Not a linux terminal, probably serial console.
193 * Force the TERM setting to vt102
194 * if TERM is set to linux (the default) */
195 if (!s
|| strcmp(s
, "linux") == 0)
196 putenv((char*)"TERM=vt102");
197 if (!ENABLE_FEATURE_INIT_SYSLOG
)
200 putenv((char*)"TERM=linux");
203 /* Set terminal settings to reasonable defaults.
204 * NB: careful, we can be called after vfork! */
205 static void set_sane_term(void)
209 tcgetattr(STDIN_FILENO
, &tty
);
211 /* set control chars */
212 tty
.c_cc
[VINTR
] = 3; /* C-c */
213 tty
.c_cc
[VQUIT
] = 28; /* C-\ */
214 tty
.c_cc
[VERASE
] = 127; /* C-? */
215 tty
.c_cc
[VKILL
] = 21; /* C-u */
216 tty
.c_cc
[VEOF
] = 4; /* C-d */
217 tty
.c_cc
[VSTART
] = 17; /* C-q */
218 tty
.c_cc
[VSTOP
] = 19; /* C-s */
219 tty
.c_cc
[VSUSP
] = 26; /* C-z */
221 /* use line discipline 0 */
224 /* Make it be sane */
225 tty
.c_cflag
&= CBAUD
| CBAUDEX
| CSIZE
| CSTOPB
| PARENB
| PARODD
;
226 tty
.c_cflag
|= CREAD
| HUPCL
| CLOCAL
;
229 tty
.c_iflag
= ICRNL
| IXON
| IXOFF
;
232 tty
.c_oflag
= OPOST
| ONLCR
;
236 ISIG
| ICANON
| ECHO
| ECHOE
| ECHOK
| ECHOCTL
| ECHOKE
| IEXTEN
;
238 tcsetattr_stdin_TCSANOW(&tty
);
241 /* Open the new terminal device.
242 * NB: careful, we can be called after vfork! */
243 static int open_stdio_to_tty(const char* tty_name
)
245 /* empty tty_name means "use init's tty", else... */
250 /* fd can be only < 0 or 0: */
251 fd
= device_open(tty_name
, O_RDWR
);
253 message(L_LOG
| L_CONSOLE
, "can't open %s: %s",
254 tty_name
, strerror(errno
));
255 return 0; /* failure */
257 dup2(STDIN_FILENO
, STDOUT_FILENO
);
258 dup2(STDIN_FILENO
, STDERR_FILENO
);
261 return 1; /* success */
264 /* Wrapper around exec:
265 * Takes string (max COMMAND_SIZE chars).
266 * If chars like '>' detected, execs '[-]/bin/sh -c "exec ......."'.
267 * Otherwise splits words on whitespace, deals with leading dash,
268 * and uses plain exec().
269 * NB: careful, we can be called after vfork!
271 static void init_exec(const char *command
)
273 char *cmd
[COMMAND_SIZE
/ 2];
274 char buf
[COMMAND_SIZE
+ 6]; /* COMMAND_SIZE+strlen("exec ")+1 */
275 int dash
= (command
[0] == '-' /* maybe? && command[1] == '/' */);
277 /* See if any special /bin/sh requiring characters are present */
278 if (strpbrk(command
, "~`!$^&*()=|\\{}[];\"'<>?") != NULL
) {
279 strcpy(buf
, "exec ");
280 strcpy(buf
+ 5, command
+ dash
); /* excluding "-" */
281 /* NB: LIBBB_DEFAULT_LOGIN_SHELL define has leading dash */
282 cmd
[0] = (char*)(LIBBB_DEFAULT_LOGIN_SHELL
+ !dash
);
283 cmd
[1] = (char*)"-c";
287 /* Convert command (char*) into cmd (char**, one word per string) */
290 next
= strcpy(buf
, command
); /* including "-" */
291 while ((word
= strsep(&next
, " \t")) != NULL
) {
292 if (*word
!= '\0') { /* not two spaces/tabs together? */
299 /* If we saw leading "-", it is interactive shell.
300 * Try harder to give it a controlling tty.
301 * And skip "-" in actual exec call. */
303 /* _Attempt_ to make stdin a controlling tty. */
304 if (ENABLE_FEATURE_INIT_SCTTY
)
305 ioctl(STDIN_FILENO
, TIOCSCTTY
, 0 /*only try, don't steal*/);
307 BB_EXECVP(cmd
[0] + dash
, cmd
);
308 message(L_LOG
| L_CONSOLE
, "cannot run '%s': %s", cmd
[0], strerror(errno
));
309 /* returns if execvp fails */
312 /* Used only by run_actions */
313 static pid_t
run(const struct init_action
*a
)
317 /* Careful: don't be affected by a signal in vforked child */
318 sigprocmask_allsigs(SIG_BLOCK
);
319 if (BB_MMU
&& (a
->action_type
& ASKFIRST
))
324 message(L_LOG
| L_CONSOLE
, "can't fork");
326 sigprocmask_allsigs(SIG_UNBLOCK
);
327 return pid
; /* Parent or error */
332 /* Reset signal handlers that were set by the parent process */
342 sigprocmask_allsigs(SIG_UNBLOCK
);
344 /* Create a new session and make ourself the process group leader */
347 /* Open the new terminal device */
348 if (!open_stdio_to_tty(a
->terminal
))
351 /* NB: on NOMMU we can't wait for input in child, so
352 * "askfirst" will work the same as "respawn". */
353 if (BB_MMU
&& (a
->action_type
& ASKFIRST
)) {
354 static const char press_enter
[] ALIGN1
=
355 #ifdef CUSTOMIZED_BANNER
356 #include CUSTOMIZED_BANNER
358 "\nPlease press Enter to activate this console. ";
361 * Save memory by not exec-ing anything large (like a shell)
362 * before the user wants it. This is critical if swap is not
363 * enabled and the system has low memory. Generally this will
364 * be run on the second virtual console, and the first will
365 * be allowed to start a shell or whatever an init script
368 dbg_message(L_LOG
, "waiting for enter to start '%s'"
369 "(pid %d, tty '%s')\n",
370 a
->command
, getpid(), a
->terminal
);
371 full_write(STDOUT_FILENO
, press_enter
, sizeof(press_enter
) - 1);
372 while (safe_read(STDIN_FILENO
, &c
, 1) == 1 && c
!= '\n')
377 * When a file named /.init_enable_core exists, setrlimit is called
378 * before processes are spawned to set core file size as unlimited.
379 * This is for debugging only. Don't use this is production, unless
380 * you want core dumps lying about....
382 if (ENABLE_FEATURE_INIT_COREDUMPS
) {
383 if (access("/.init_enable_core", F_OK
) == 0) {
385 limit
.rlim_cur
= RLIM_INFINITY
;
386 limit
.rlim_max
= RLIM_INFINITY
;
387 setrlimit(RLIMIT_CORE
, &limit
);
391 /* Log the process name and args */
392 message(L_LOG
, "starting pid %d, tty '%s': '%s'",
393 getpid(), a
->terminal
, a
->command
);
395 /* Now run it. The new program will take over this PID,
396 * so nothing further in init.c should be run. */
397 init_exec(a
->command
);
398 /* We're still here? Some error happened. */
402 static struct init_action
*mark_terminated(pid_t pid
)
404 struct init_action
*a
;
407 for (a
= init_action_list
; a
; a
= a
->next
) {
417 static void waitfor(pid_t pid
)
419 /* waitfor(run(x)): protect against failed fork inside run() */
423 /* Wait for any child (prevent zombies from exiting orphaned processes)
424 * but exit the loop only when specified one has exited. */
426 pid_t wpid
= wait(NULL
);
427 mark_terminated(wpid
);
428 /* Unsafe. SIGTSTP handler might have wait'ed it already */
429 /*if (wpid == pid) break;*/
436 /* Run all commands of a particular type */
437 static void run_actions(int action_type
)
439 struct init_action
*a
;
441 for (a
= init_action_list
; a
; a
= a
->next
) {
442 if (!(a
->action_type
& action_type
))
445 if (a
->action_type
& (SYSINIT
| WAIT
| ONCE
| CTRLALTDEL
| SHUTDOWN
)) {
447 if (a
->action_type
& (SYSINIT
| WAIT
| CTRLALTDEL
| SHUTDOWN
))
450 if (a
->action_type
& (RESPAWN
| ASKFIRST
)) {
451 /* Only run stuff with pid == 0. If pid != 0,
452 * it is already running
460 static void new_init_action(uint8_t action_type
, const char *command
, const char *cons
)
462 struct init_action
*a
, **nextp
;
466 * ::shutdown:umount -a -r
467 * ::shutdown:swapoff -a
469 * ::shutdown:swapoff -a
470 * ::shutdown:umount -a -r
471 * On reload, we must ensure entries end up in correct order.
472 * To achieve that, if we find a matching entry, we move it
475 nextp
= &init_action_list
;
476 while ((a
= *nextp
) != NULL
) {
477 /* Don't enter action if it's already in the list,
478 * This prevents losing running RESPAWNs.
480 if ((strcmp(a
->command
, command
) == 0)
481 && (strcmp(a
->terminal
, cons
) == 0)
483 /* Remove from list */
485 /* Find the end of the list */
486 while (*nextp
!= NULL
)
487 nextp
= &(*nextp
)->next
;
495 a
= xzalloc(sizeof(*a
));
496 /* Append to the end of the list */
498 a
->action_type
= action_type
;
499 safe_strncpy(a
->command
, command
, sizeof(a
->command
));
500 safe_strncpy(a
->terminal
, cons
, sizeof(a
->terminal
));
501 dbg_message(L_LOG
| L_CONSOLE
, "command='%s' action=%d tty='%s'\n",
502 a
->command
, a
->action_type
, a
->terminal
);
505 /* NOTE that if CONFIG_FEATURE_USE_INITTAB is NOT defined,
506 * then parse_inittab() simply adds in some default
507 * actions(i.e., runs INIT_SCRIPT and then starts a pair
508 * of "askfirst" shells). If CONFIG_FEATURE_USE_INITTAB
509 * _is_ defined, but /etc/inittab is missing, this
510 * results in the same set of default behaviors.
512 static void parse_inittab(void)
514 #if ENABLE_FEATURE_USE_INITTAB
516 parser_t
*parser
= config_open2("/etc/inittab", fopen_for_read
);
521 /* No inittab file - set up some default behavior */
522 /* Reboot on Ctrl-Alt-Del */
523 new_init_action(CTRLALTDEL
, "reboot", "");
524 /* Umount all filesystems on halt/reboot */
525 new_init_action(SHUTDOWN
, "umount -a -r", "");
526 /* Swapoff on halt/reboot */
527 if (ENABLE_SWAPONOFF
)
528 new_init_action(SHUTDOWN
, "swapoff -a", "");
529 /* Prepare to restart init when a QUIT is received */
530 new_init_action(RESTART
, "init", "");
531 /* Askfirst shell on tty1-4 */
532 new_init_action(ASKFIRST
, bb_default_login_shell
, "");
533 //TODO: VC_1 instead of ""? "" is console -> ctty problems -> angry users
534 new_init_action(ASKFIRST
, bb_default_login_shell
, VC_2
);
535 new_init_action(ASKFIRST
, bb_default_login_shell
, VC_3
);
536 new_init_action(ASKFIRST
, bb_default_login_shell
, VC_4
);
538 new_init_action(SYSINIT
, INIT_SCRIPT
, "");
542 #if ENABLE_FEATURE_USE_INITTAB
543 /* optional_tty:ignored_runlevel:action:command
544 * Delims are not to be collapsed and need exactly 4 tokens
546 while (config_read(parser
, token
, 4, 0, "#:",
547 PARSE_NORMAL
& ~(PARSE_TRIM
| PARSE_COLLAPSE
))) {
548 /* order must correspond to SYSINIT..RESTART constants */
549 static const char actions
[] ALIGN1
=
550 "sysinit\0""wait\0""once\0""respawn\0""askfirst\0"
551 "ctrlaltdel\0""shutdown\0""restart\0";
553 char *tty
= token
[0];
555 if (!token
[3]) /* less than 4 tokens */
557 action
= index_in_strings(actions
, token
[2]);
558 if (action
< 0 || !token
[3][0]) /* token[3]: command */
560 /* turn .*TTY -> /dev/TTY */
562 if (strncmp(tty
, "/dev/", 5) == 0)
564 tty
= concat_path_file("/dev/", tty
);
566 new_init_action(1 << action
, token
[3], tty
);
571 message(L_LOG
| L_CONSOLE
, "Bad inittab entry at line %d",
574 config_close(parser
);
578 static void pause_and_low_level_reboot(unsigned magic
) NORETURN
;
579 static void pause_and_low_level_reboot(unsigned magic
)
583 /* Allow time for last message to reach serial console, etc */
586 /* We have to fork here, since the kernel calls do_exit(EXIT_SUCCESS)
587 * in linux/kernel/sys.c, which can cause the machine to panic when
588 * the init process exits... */
590 if (pid
== 0) { /* child */
598 static void run_shutdown_and_kill_processes(void)
600 /* Run everything to be run at "shutdown". This is done _prior_
601 * to killing everything, in case people wish to use scripts to
602 * shut things down gracefully... */
603 run_actions(SHUTDOWN
);
605 message(L_CONSOLE
| L_LOG
, "The system is going down NOW!");
607 /* Send signals to every process _except_ pid 1 */
609 message(L_CONSOLE
| L_LOG
, "Sent SIG%s to all processes", "TERM");
614 message(L_CONSOLE
, "Sent SIG%s to all processes", "KILL");
616 /*sleep(1); - callers take care about making a pause */
619 /* Signal handling by init:
621 * For process with PID==1, on entry kernel sets all signals to SIG_DFL
622 * and unmasks all signals. However, for process with PID==1,
623 * default action (SIG_DFL) on any signal is to ignore it,
624 * even for special signals SIGKILL and SIGCONT.
625 * Also, any signal can be caught or blocked.
626 * (but SIGSTOP is still handled specially, at least in 2.6.20)
628 * We install two kinds of handlers, "immediate" and "delayed".
630 * Immediate handlers execute at any time, even while, say, sysinit
633 * Delayed handlers just set a flag variable. The variable is checked
634 * in the main loop and acted upon.
636 * halt/poweroff/reboot and restart have immediate handlers.
637 * They only traverse linked list of struct action's, never modify it,
638 * this should be safe to do even in signal handler. Also they
641 * SIGSTOP and SIGTSTP have immediate handlers. They just wait
642 * for SIGCONT to happen.
644 * SIGHUP has a delayed handler, because modifying linked list
645 * of struct action's from a signal handler while it is manipulated
646 * by the program may be disastrous.
648 * Ctrl-Alt-Del has a delayed handler. Not a must, but allowing
649 * it to happen even somewhere inside "sysinit" would be a bit awkward.
651 * There is a tiny probability that SIGHUP and Ctrl-Alt-Del will collide
652 * and only one will be remembered and acted upon.
655 static void halt_reboot_pwoff(int sig
) NORETURN
;
656 static void halt_reboot_pwoff(int sig
)
661 run_shutdown_and_kill_processes();
665 if (sig
== SIGTERM
) {
668 } else if (sig
== SIGUSR2
) {
672 message(L_CONSOLE
, "Requesting system %s", m
);
673 pause_and_low_level_reboot(rb
);
677 /* The SIGSTOP/SIGTSTP handler
678 * NB: inside it, all signals except SIGCONT are masked
679 * via appropriate setup in sigaction().
681 static void stop_handler(int sig UNUSED_PARAM
)
683 smallint saved_bb_got_signal
;
686 saved_bb_got_signal
= bb_got_signal
;
688 signal(SIGCONT
, record_signo
);
693 if (bb_got_signal
== SIGCONT
)
695 /* NB: this can accidentally wait() for a process
696 * which we waitfor() elsewhere! waitfor() must have
697 * code which is resilient against this.
699 wpid
= wait_any_nohang(NULL
);
700 mark_terminated(wpid
);
704 signal(SIGCONT
, SIG_DFL
);
706 bb_got_signal
= saved_bb_got_signal
;
709 /* Handler for QUIT - exec "restart" action,
710 * else (no such action defined) do nothing */
711 static void restart_handler(int sig UNUSED_PARAM
)
713 struct init_action
*a
;
715 for (a
= init_action_list
; a
; a
= a
->next
) {
716 if (!(a
->action_type
& RESTART
))
719 /* Starting from here, we won't return.
720 * Thus don't need to worry about preserving errno
723 run_shutdown_and_kill_processes();
725 /* Allow Ctrl-Alt-Del to reboot the system.
726 * This is how kernel sets it up for init, we follow suit.
728 reboot(RB_ENABLE_CAD
); /* misnomer */
730 if (open_stdio_to_tty(a
->terminal
)) {
731 dbg_message(L_CONSOLE
, "Trying to re-exec %s", a
->command
);
732 /* Theoretically should be safe.
733 * But in practice, kernel bugs may leave
734 * unkillable processes, and wait() may block forever.
735 * Oh well. Hoping "new" init won't be too surprised
736 * by having children it didn't create.
738 //while (wait(NULL) > 0)
740 init_exec(a
->command
);
742 /* Open or exec failed */
743 pause_and_low_level_reboot(RB_HALT_SYSTEM
);
748 #if ENABLE_FEATURE_USE_INITTAB
749 static void reload_inittab(void)
751 struct init_action
*a
, **nextp
;
753 message(L_LOG
, "reloading /etc/inittab");
755 /* Disable old entries */
756 for (a
= init_action_list
; a
; a
= a
->next
)
757 a
->action_type
= ONCE
;
759 /* Append new entries, or modify existing entries
760 * (set a->action_type) if cmd and device name
761 * match new ones. End result: only entries with
762 * a->action_type == ONCE are stale.
766 #if ENABLE_FEATURE_KILL_REMOVED
767 /* Kill stale entries */
768 /* Be nice and send SIGTERM first */
769 for (a
= init_action_list
; a
; a
= a
->next
)
770 if (a
->action_type
== ONCE
&& a
->pid
!= 0)
771 kill(a
->pid
, SIGTERM
);
772 if (CONFIG_FEATURE_KILL_DELAY
) {
773 /* NB: parent will wait in NOMMU case */
774 if ((BB_MMU
? fork() : vfork()) == 0) { /* child */
775 sleep(CONFIG_FEATURE_KILL_DELAY
);
776 for (a
= init_action_list
; a
; a
= a
->next
)
777 if (a
->action_type
== ONCE
&& a
->pid
!= 0)
778 kill(a
->pid
, SIGKILL
);
784 /* Remove stale (ONCE) and not useful (SYSINIT,WAIT) entries */
785 nextp
= &init_action_list
;
786 while ((a
= *nextp
) != NULL
) {
787 if (a
->action_type
& (ONCE
| SYSINIT
| WAIT
)) {
796 /* run_actions(RESPAWN | ASKFIRST); */
797 /* - we return to main loop, which does this automagically */
801 static int check_delayed_sigs(void)
806 smallint sig
= bb_got_signal
;
812 #if ENABLE_FEATURE_USE_INITTAB
817 run_actions(CTRLALTDEL
);
821 int init_main(int argc
, char **argv
) MAIN_EXTERNALLY_VISIBLE
;
822 int init_main(int argc UNUSED_PARAM
, char **argv
)
824 die_sleep
= 30 * 24*60*60; /* if xmalloc would ever die... */
826 if (argv
[1] && !strcmp(argv
[1], "-q")) {
827 return kill(1, SIGHUP
);
831 /* Expect to be invoked as init with PID=1 or be invoked as linuxrc */
833 && (!ENABLE_FEATURE_INITRD
|| !strstr(applet_name
, "linuxrc"))
837 /* Turn off rebooting via CTL-ALT-DEL - we get a
838 * SIGINT on CAD so we can shut things down gracefully... */
839 reboot(RB_DISABLE_CAD
); /* misnomer */
842 /* Figure out where the default console should be */
848 /* Make sure environs is set to something sane */
849 putenv((char *) "HOME=/");
850 putenv((char *) bb_PATH_root_path
);
851 putenv((char *) "SHELL=/bin/sh");
852 putenv((char *) "USER=root"); /* needed? why? */
855 xsetenv("RUNLEVEL", argv
[1]);
858 message(MAYBE_CONSOLE
| L_LOG
, "init started: %s", bb_banner
);
860 /* Make sure there is enough memory to do something useful. */
861 if (ENABLE_SWAPONOFF
) {
864 if (sysinfo(&info
) == 0
865 && (info
.mem_unit
? : 1) * (long long)info
.totalram
< 1024*1024
867 message(L_CONSOLE
, "Low memory, forcing swapon");
868 /* swapon -a requires /proc typically */
869 new_init_action(SYSINIT
, "mount -t proc proc /proc", "");
870 /* Try to turn on swap */
871 new_init_action(SYSINIT
, "swapon -a", "");
872 run_actions(SYSINIT
); /* wait and removing */
876 /* Check if we are supposed to be in single user mode */
878 && (!strcmp(argv
[1], "single") || !strcmp(argv
[1], "-s") || LONE_CHAR(argv
[1], '1'))
880 /* ??? shouldn't we set RUNLEVEL="b" here? */
881 /* Start a shell on console */
882 new_init_action(RESPAWN
, bb_default_login_shell
, "");
884 /* Not in single user mode - see what inittab says */
886 /* NOTE that if CONFIG_FEATURE_USE_INITTAB is NOT defined,
887 * then parse_inittab() simply adds in some default
888 * actions(i.e., INIT_SCRIPT and a pair
889 * of "askfirst" shells */
894 if (getenv("SELINUX_INIT") == NULL
) {
897 putenv((char*)"SELINUX_INIT=YES");
898 if (selinux_init_load_policy(&enforce
) == 0) {
899 BB_EXECVP(argv
[0], argv
);
900 } else if (enforce
> 0) {
901 /* SELinux in enforcing mode but load_policy failed */
902 message(L_CONSOLE
, "cannot load SELinux Policy. "
903 "Machine is in enforcing mode. Halting now.");
909 /* Make the command line just say "init" - thats all, nothing else */
910 strncpy(argv
[0], "init", strlen(argv
[0]));
911 /* Wipe argv[1]-argv[N] so they don't clutter the ps listing */
913 memset(*argv
, 0, strlen(*argv
));
915 /* Set up signal handlers */
920 + (1 << SIGUSR1
) /* halt */
921 + (1 << SIGTERM
) /* reboot */
922 + (1 << SIGUSR2
) /* poweroff */
923 , halt_reboot_pwoff
);
924 signal(SIGQUIT
, restart_handler
); /* re-exec another init */
926 /* Stop handler must allow only SIGCONT inside itself */
927 memset(&sa
, 0, sizeof(sa
));
928 sigfillset(&sa
.sa_mask
);
929 sigdelset(&sa
.sa_mask
, SIGCONT
);
930 sa
.sa_handler
= stop_handler
;
931 /* NB: sa_flags doesn't have SA_RESTART.
932 * It must be able to interrupt wait().
934 sigaction_set(SIGTSTP
, &sa
); /* pause */
935 /* Does not work as intended, at least in 2.6.20.
936 * SIGSTOP is simply ignored by init:
938 sigaction_set(SIGSTOP
, &sa
); /* pause */
940 /* SIGINT (Ctrl-Alt-Del) must interrupt wait(),
941 * setting handler without SA_RESTART flag.
943 bb_signals_recursive_norestart((1 << SIGINT
), record_signo
);
946 /* Now run everything that needs to be run */
947 /* First run the sysinit command */
948 run_actions(SYSINIT
);
949 check_delayed_sigs();
950 /* Next run anything that wants to block */
952 check_delayed_sigs();
953 /* Next run anything to be run only once */
956 /* Set up "reread /etc/inittab" handler.
957 * Handler is set up without SA_RESTART, it will interrupt syscalls.
959 if (!DEBUG_INIT
&& ENABLE_FEATURE_USE_INITTAB
)
960 bb_signals_recursive_norestart((1 << SIGHUP
), record_signo
);
962 /* Now run the looping stuff for the rest of forever.
963 * NB: if delayed signal happened, avoid blocking in wait().
968 maybe_WNOHANG
= check_delayed_sigs();
970 /* (Re)run the respawn/askfirst stuff */
971 run_actions(RESPAWN
| ASKFIRST
);
972 maybe_WNOHANG
|= check_delayed_sigs();
974 /* Don't consume all CPU time - sleep a bit */
976 maybe_WNOHANG
|= check_delayed_sigs();
978 /* Wait for any child process(es) to exit.
979 * NB: "delayed" signals will also interrupt this wait(),
980 * bb_signals_recursive_norestart() set them up for that.
981 * This guarantees we won't be stuck here
982 * till next orphan dies.
985 maybe_WNOHANG
= WNOHANG
;
988 struct init_action
*a
;
990 wpid
= waitpid(-1, NULL
, maybe_WNOHANG
);
994 a
= mark_terminated(wpid
);
996 message(L_LOG
, "process '%s' (pid %d) exited. "
997 "Scheduling for restart.",
1000 /* See if anyone else is waiting to be reaped */
1001 maybe_WNOHANG
= WNOHANG
;