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>
19 /* Was a CONFIG_xxx option. A lot of people were building
20 * not fully functional init by switching it on! */
23 #define COMMAND_SIZE 256
24 #define CONSOLE_NAME_SIZE 32
26 /* Default sysinit script. */
28 #define INIT_SCRIPT "/etc/init.d/rcS"
31 /* Each type of actions can appear many times. They will be
32 * handled in order. RESTART is an exception, only 1st is used.
34 /* Start these actions first and wait for completion */
36 /* Start these after SYSINIT and wait for completion */
38 /* Start these after WAIT and *dont* wait for completion */
41 * NB: while SYSINIT/WAIT/ONCE are being processed,
42 * SIGHUP ("reread /etc/inittab") will be ignored.
43 * Rationale: it would be ambiguous whether SYSINIT/WAIT/ONCE
44 * need to be rerun or not.
46 /* Start these after ONCE are started, restart on exit */
48 /* Like RESPAWN, but wait for <Enter> to be pressed on tty */
51 * Start these on SIGINT, and wait for completion.
52 * Then go back to respawning RESPAWN and ASKFIRST actions.
53 * NB: kernel sends SIGINT to us if Ctrl-Alt-Del was pressed.
55 #define CTRLALTDEL 0x20
57 * Start these before killing all processes in preparation for
58 * running RESTART actions or doing low-level halt/reboot/poweroff
59 * (initiated by SIGUSR1/SIGTERM/SIGUSR2).
60 * Wait for completion before proceeding.
64 * exec() on SIGQUIT. SHUTDOWN actions are started and waited for,
65 * then all processes are killed, then init exec's 1st RESTART action,
66 * replacing itself by it. If no RESTART action specified,
67 * SIGQUIT has no effect.
72 /* A linked list of init_actions, to be read from inittab */
74 struct init_action *next;
77 char terminal[CONSOLE_NAME_SIZE];
78 char command[COMMAND_SIZE];
81 static struct init_action *init_action_list = NULL;
83 static const char *log_console = VC_5;
88 MAYBE_CONSOLE = L_CONSOLE * !ENABLE_FEATURE_EXTRA_QUIET,
89 #ifndef RB_HALT_SYSTEM
90 RB_HALT_SYSTEM = 0xcdef0123, /* FIXME: this overflows enum */
91 RB_ENABLE_CAD = 0x89abcdef,
93 RB_POWER_OFF = 0x4321fedc,
94 RB_AUTOBOOT = 0x01234567,
98 static void halt_reboot_pwoff(int sig) NORETURN;
100 /* Print a message to the specified device.
101 * "where" may be bitwise-or'd from L_LOG | L_CONSOLE
102 * NB: careful, we can be called after vfork!
104 #define messageD(...) do { if (DEBUG_INIT) message(__VA_ARGS__); } while (0)
105 static void message(int where, const char *fmt, ...)
106 __attribute__ ((format(printf, 2, 3)));
107 static void message(int where, const char *fmt, ...)
109 static int log_fd = -1;
115 va_start(arguments, fmt);
116 l = 1 + vsnprintf(msg + 1, sizeof(msg) - 2, fmt, arguments);
117 if (l > sizeof(msg) - 1)
122 if (ENABLE_FEATURE_INIT_SYSLOG) {
124 /* Log the message to syslogd */
125 openlog("init", 0, LOG_DAEMON);
126 /* don't print "\r" */
127 syslog(LOG_INFO, "%s", msg + 1);
135 /* Take full control of the log tty, and never close it.
136 * It's mine, all mine! Muhahahaha! */
139 log_fd = STDERR_FILENO;
141 log_fd = device_open(log_console, O_WRONLY | O_NONBLOCK | O_NOCTTY);
143 bb_error_msg("can't log to %s", log_console);
146 close_on_exec_on(log_fd);
151 full_write(log_fd, msg, l);
152 if (log_fd == STDERR_FILENO)
153 return; /* don't print dup messages */
157 if (where & L_CONSOLE) {
158 /* Send console messages to console so people will see them. */
159 full_write(STDERR_FILENO, msg, l);
163 /* From <linux/serial.h> */
164 struct serial_struct {
173 unsigned short close_delay;
175 char reserved_char[1];
177 unsigned short closing_wait; /* time to wait before closing */
178 unsigned short closing_wait2; /* no longer used... */
179 unsigned char *iomem_base;
180 unsigned short iomem_reg_shift;
181 unsigned int port_high;
182 unsigned long iomap_base; /* cookie passed into ioremap */
184 /* Paranoia (imagine 64bit kernel overwriting 32bit userspace stack) */
185 uint32_t bbox_reserved[16];
187 static void console_init(void)
189 struct serial_struct sr;
192 s = getenv("CONSOLE");
194 s = getenv("console");
196 int fd = open(s, O_RDWR | O_NONBLOCK | O_NOCTTY);
198 dup2(fd, STDIN_FILENO);
199 dup2(fd, STDOUT_FILENO);
200 xmove_fd(fd, STDERR_FILENO);
202 messageD(L_LOG, "console='%s'", s);
204 /* Make sure fd 0,1,2 are not closed
205 * (so that they won't be used by future opens) */
207 // Users report problems
208 // /* Make sure init can't be blocked by writing to stderr */
209 // fcntl(STDERR_FILENO, F_SETFL, fcntl(STDERR_FILENO, F_GETFL) | O_NONBLOCK);
213 if (ioctl(STDIN_FILENO, TIOCGSERIAL, &sr) == 0) {
214 /* Force the TERM setting to vt102 for serial console
215 * if TERM is set to linux (the default) */
216 if (!s || strcmp(s, "linux") == 0)
217 putenv((char*)"TERM=vt102");
218 if (!ENABLE_FEATURE_INIT_SYSLOG)
221 putenv((char*)"TERM=linux");
224 /* Set terminal settings to reasonable defaults.
225 * NB: careful, we can be called after vfork! */
226 static void set_sane_term(void)
230 tcgetattr(STDIN_FILENO, &tty);
232 /* set control chars */
233 tty.c_cc[VINTR] = 3; /* C-c */
234 tty.c_cc[VQUIT] = 28; /* C-\ */
235 tty.c_cc[VERASE] = 127; /* C-? */
236 tty.c_cc[VKILL] = 21; /* C-u */
237 tty.c_cc[VEOF] = 4; /* C-d */
238 tty.c_cc[VSTART] = 17; /* C-q */
239 tty.c_cc[VSTOP] = 19; /* C-s */
240 tty.c_cc[VSUSP] = 26; /* C-z */
242 /* use line discipline 0 */
245 /* Make it be sane */
246 tty.c_cflag &= CBAUD | CBAUDEX | CSIZE | CSTOPB | PARENB | PARODD;
247 tty.c_cflag |= CREAD | HUPCL | CLOCAL;
250 tty.c_iflag = ICRNL | IXON | IXOFF;
253 tty.c_oflag = OPOST | ONLCR;
257 ISIG | ICANON | ECHO | ECHOE | ECHOK | ECHOCTL | ECHOKE | IEXTEN;
259 tcsetattr_stdin_TCSANOW(&tty);
262 /* Open the new terminal device.
263 * NB: careful, we can be called after vfork! */
264 static void open_stdio_to_tty(const char* tty_name, int exit_on_failure)
266 /* empty tty_name means "use init's tty", else... */
271 /* fd can be only < 0 or 0: */
272 fd = device_open(tty_name, O_RDWR);
274 message(L_LOG | L_CONSOLE, "can't open %s: %s",
275 tty_name, strerror(errno));
280 /* NB: we don't reach this if we were called after vfork.
281 * Thus halt_reboot_pwoff() itself needs not be vfork-safe.
283 halt_reboot_pwoff(SIGUSR1); /* halt the system */
285 dup2(STDIN_FILENO, STDOUT_FILENO);
286 dup2(STDIN_FILENO, STDERR_FILENO);
291 /* Wrapper around exec:
292 * Takes string (max COMMAND_SIZE chars).
293 * If chars like '>' detected, execs '[-]/bin/sh -c "exec ......."'.
294 * Otherwise splits words on whitespace, deals with leading dash,
295 * and uses plain exec().
296 * NB: careful, we can be called after vfork!
298 static void init_exec(const char *command)
300 char *cmd[COMMAND_SIZE / 2];
301 char buf[COMMAND_SIZE + 6]; /* COMMAND_SIZE+strlen("exec ")+1 */
302 int dash = (command[0] == '-' /* maybe? && command[1] == '/' */);
304 /* See if any special /bin/sh requiring characters are present */
305 if (strpbrk(command, "~`!$^&*()=|\\{}[];\"'<>?") != NULL) {
306 strcpy(buf, "exec ");
307 strcpy(buf + 5, command + dash); /* excluding "-" */
308 /* NB: LIBBB_DEFAULT_LOGIN_SHELL define has leading dash */
309 cmd[0] = (char*)(LIBBB_DEFAULT_LOGIN_SHELL + !dash);
310 cmd[1] = (char*)"-c";
314 /* Convert command (char*) into cmd (char**, one word per string) */
317 next = strcpy(buf, command); /* including "-" */
318 while ((word = strsep(&next, " \t")) != NULL) {
319 if (*word != '\0') { /* not two spaces/tabs together? */
326 /* If we saw leading "-", it is interactive shell.
327 * Try harder to give it a controlling tty.
328 * And skip "-" in actual exec call. */
330 /* _Attempt_ to make stdin a controlling tty. */
331 if (ENABLE_FEATURE_INIT_SCTTY)
332 ioctl(STDIN_FILENO, TIOCSCTTY, 0 /*only try, don't steal*/);
334 BB_EXECVP(cmd[0] + dash, cmd);
335 message(L_LOG | L_CONSOLE, "cannot run '%s': %s", cmd[0], strerror(errno));
336 /* returns if execvp fails */
339 /* Used only by run_actions */
340 static pid_t run(const struct init_action *a)
344 if (BB_MMU && (a->action_type & ASKFIRST))
349 message(L_LOG | L_CONSOLE, "can't fork");
351 return pid; /* Parent or error */
355 /* Reset signal handlers that were set by the parent process */
356 //TODO: block signals across fork(), prevent them to affect child before
368 /* Create a new session and make ourself the process group leader */
371 /* Open the new terminal device */
372 open_stdio_to_tty(a->terminal, 1 /* - exit if open fails */);
374 /* NB: on NOMMU we can't wait for input in child, so
375 * "askfirst" will work the same as "respawn". */
376 if (BB_MMU && (a->action_type & ASKFIRST)) {
377 static const char press_enter[] ALIGN1 =
378 #ifdef CUSTOMIZED_BANNER
379 #include CUSTOMIZED_BANNER
381 "\nPlease press Enter to activate this console. ";
384 * Save memory by not exec-ing anything large (like a shell)
385 * before the user wants it. This is critical if swap is not
386 * enabled and the system has low memory. Generally this will
387 * be run on the second virtual console, and the first will
388 * be allowed to start a shell or whatever an init script
391 messageD(L_LOG, "waiting for enter to start '%s'"
392 "(pid %d, tty '%s')\n",
393 a->command, getpid(), a->terminal);
394 full_write(STDOUT_FILENO, press_enter, sizeof(press_enter) - 1);
395 while (safe_read(STDIN_FILENO, &c, 1) == 1 && c != '\n')
400 * When a file named /.init_enable_core exists, setrlimit is called
401 * before processes are spawned to set core file size as unlimited.
402 * This is for debugging only. Don't use this is production, unless
403 * you want core dumps lying about....
405 if (ENABLE_FEATURE_INIT_COREDUMPS) {
406 if (access("/.init_enable_core", F_OK) == 0) {
408 limit.rlim_cur = RLIM_INFINITY;
409 limit.rlim_max = RLIM_INFINITY;
410 setrlimit(RLIMIT_CORE, &limit);
414 /* Log the process name and args */
415 message(L_LOG, "starting pid %d, tty '%s': '%s'",
416 getpid(), a->terminal, a->command);
418 /* Now run it. The new program will take over this PID,
419 * so nothing further in init.c should be run. */
420 init_exec(a->command);
421 /* We're still here? Some error happened. */
425 static void delete_init_action(struct init_action *action)
427 struct init_action *a, **nextp;
429 nextp = &init_action_list;
430 while ((a = *nextp) != NULL) {
440 static struct init_action *mark_terminated(int pid)
442 struct init_action *a;
444 for (a = init_action_list; a; a = a->next) {
453 static void waitfor(pid_t pid)
455 /* waitfor(run(x)): protect against failed fork inside run() */
459 /* Wait for any child (prevent zombies from exiting orphaned processes)
460 * but exit the loop only when specified one has exited. */
462 pid_t wpid = wait(NULL);
463 mark_terminated(wpid);
464 /* Unsafe. SIGTSTP handler might have wait'ed it already */
465 /*if (wpid == pid) break;*/
472 /* Run all commands of a particular type */
473 static void run_actions(int action_type)
475 struct init_action *a;
477 for (a = init_action_list; a; a = a->next) {
478 if (!(a->action_type & action_type))
481 if (a->action_type & (SYSINIT | WAIT | ONCE | CTRLALTDEL | SHUTDOWN)) {
483 if (a->action_type & (SYSINIT | WAIT | CTRLALTDEL | SHUTDOWN))
486 if (a->action_type & (RESPAWN | ASKFIRST)) {
487 /* Only run stuff with pid == 0. If pid != 0,
488 * it is already running
496 static void new_init_action(uint8_t action_type, const char *command, const char *cons)
498 struct init_action *a, **nextp;
502 //::shutdown:umount -a -r
503 //::shutdown:swapoff -a
505 //::shutdown:swapoff -a
506 //::shutdown:umount -a -r
507 //on SIGHUP, new one will be loaded, but order will be wrong.
508 nextp = &init_action_list;
509 while ((a = *nextp) != NULL) {
510 /* Don't enter action if it's already in the list,
511 * just overwrite existing one's type.
512 * This prevents losing running RESPAWNs.
514 if ((strcmp(a->command, command) == 0)
515 && (strcmp(a->terminal, cons) == 0)
517 a->action_type = action_type;
523 /* Append to the end of the list */
524 a = xzalloc(sizeof(*a));
526 a->action_type = action_type;
527 safe_strncpy(a->command, command, sizeof(a->command));
528 safe_strncpy(a->terminal, cons, sizeof(a->terminal));
529 messageD(L_LOG | L_CONSOLE, "command='%s' action=%d tty='%s'\n",
530 a->command, a->action_type, a->terminal);
533 /* NOTE that if CONFIG_FEATURE_USE_INITTAB is NOT defined,
534 * then parse_inittab() simply adds in some default
535 * actions(i.e., runs INIT_SCRIPT and then starts a pair
536 * of "askfirst" shells). If CONFIG_FEATURE_USE_INITTAB
537 * _is_ defined, but /etc/inittab is missing, this
538 * results in the same set of default behaviors.
540 static void parse_inittab(void)
542 #if ENABLE_FEATURE_USE_INITTAB
544 parser_t *parser = config_open2("/etc/inittab", fopen_for_read);
549 /* No inittab file - set up some default behavior */
550 /* Reboot on Ctrl-Alt-Del */
551 new_init_action(CTRLALTDEL, "reboot", "");
552 /* Umount all filesystems on halt/reboot */
553 new_init_action(SHUTDOWN, "umount -a -r", "");
554 /* Swapoff on halt/reboot */
555 if (ENABLE_SWAPONOFF)
556 new_init_action(SHUTDOWN, "swapoff -a", "");
557 /* Prepare to restart init when a QUIT is received */
558 new_init_action(RESTART, "init", "");
559 /* Askfirst shell on tty1-4 */
560 new_init_action(ASKFIRST, bb_default_login_shell, "");
561 //TODO: VC_1 instead of ""? "" is console -> ctty problems -> angry users
562 new_init_action(ASKFIRST, bb_default_login_shell, VC_2);
563 new_init_action(ASKFIRST, bb_default_login_shell, VC_3);
564 new_init_action(ASKFIRST, bb_default_login_shell, VC_4);
566 new_init_action(SYSINIT, INIT_SCRIPT, "");
570 #if ENABLE_FEATURE_USE_INITTAB
571 /* optional_tty:ignored_runlevel:action:command
572 * Delims are not to be collapsed and need exactly 4 tokens
574 while (config_read(parser, token, 4, 0, "#:",
575 PARSE_NORMAL & ~(PARSE_TRIM | PARSE_COLLAPSE))) {
576 /* order must correspond to SYSINIT..RESTART constants */
577 static const char actions[] ALIGN1 =
578 "sysinit\0""wait\0""once\0""respawn\0""askfirst\0"
579 "ctrlaltdel\0""shutdown\0""restart\0";
581 char *tty = token[0];
583 if (!token[3]) /* less than 4 tokens */
585 action = index_in_strings(actions, token[2]);
586 if (action < 0 || !token[3][0]) /* token[3]: command */
588 /* turn .*TTY -> /dev/TTY */
590 if (strncmp(tty, "/dev/", 5) == 0)
592 tty = concat_path_file("/dev/", tty);
594 new_init_action(1 << action, token[3], tty);
599 message(L_LOG | L_CONSOLE, "Bad inittab entry at line %d",
602 config_close(parser);
606 static void low_level_reboot(unsigned magic) NORETURN;
607 static void low_level_reboot(unsigned magic)
611 /* Allow time for last message to reach serial console, etc */
614 /* We have to fork here, since the kernel calls do_exit(EXIT_SUCCESS)
615 * in linux/kernel/sys.c, which can cause the machine to panic when
616 * the init process exits... */
618 if (pid == 0) { /* child */
627 static void kill_all_processes(void)
629 /* Run everything to be run at "shutdown". This is done _prior_
630 * to killing everything, in case people wish to use scripts to
631 * shut things down gracefully... */
632 run_actions(SHUTDOWN);
634 message(L_CONSOLE | L_LOG, "The system is going down NOW!");
636 /* Allow Ctrl-Alt-Del to reboot system. */
637 reboot(RB_ENABLE_CAD); /* misnomer */
639 /* Send signals to every process _except_ pid 1 */
640 message(L_CONSOLE | L_LOG, "Sending SIG%s to all processes", "TERM");
645 message(L_CONSOLE, "Sending SIG%s to all processes", "KILL");
651 /* Signal handling by init:
653 * For process with PID==1, on entry kernel sets all signals to SIG_DFL
654 * and unmasks all signals. However, for process with PID==1,
655 * default action (SIG_DFL) on any signal is to ignore it,
656 * even for special signals SIGKILL and SIGCONT.
657 * Also, any signal can be caught or blocked.
658 * (but SIGSTOP is still handled specially, at least in 2.6.20)
660 * We install two kinds of handlers, "immediate" and "delayed".
662 * Immediate handlers execute at any time, even while, say, sysinit
665 * Delayed handlers just set a flag variable. The variable is checked
666 * in the main loop and acted upon.
668 * halt/poweroff/reboot and restart have immediate handlers.
669 * They only traverse linked list of struct action's, never modify it,
670 * this should be safe to do even in signal handler. Also they
673 * SIGSTOP and SIGTSTP have immediate handlers. They just wait
674 * for SIGCONT to happen.
676 * SIGHUP has a delayed handler, because modifying linked list
677 * of struct action's from a signal handler while it is manipulated
678 * by the program may be disastrous.
680 * Ctrl-Alt-Del has a delayed handler. Not a must, but allowing
681 * it to happen even somewhere inside "sysinit" would be a bit awkward.
683 * There is a tiny probability that SIGHUP and Ctrl-Alt-Del will collide
684 * and only one will be remebered and acted upon.
687 static void halt_reboot_pwoff(int sig)
692 kill_all_processes();
696 if (sig == SIGTERM) {
699 } else if (sig == SIGUSR2) {
703 message(L_CONSOLE, "Requesting system %s", m);
704 low_level_reboot(rb);
708 /* The SIGSTOP/SIGTSTP handler
709 * NB: inside it, all signals except SIGCONT are masked
710 * via appropriate setup in sigaction().
712 static void stop_handler(int sig UNUSED_PARAM)
715 smallint saved_bb_got_signal;
718 saved_bb_got_signal = bb_got_signal;
719 signal(SIGCONT, record_signo);
724 if (bb_got_signal == SIGCONT)
726 /* NB: this can accidentally wait() for a process
727 * which we waitfor() elsewhere! waitfor() must have
728 * code which is resilient against this.
730 wpid = wait_any_nohang(NULL);
732 mark_terminated(wpid);
736 signal(SIGCONT, SIG_DFL);
737 bb_got_signal = saved_bb_got_signal;
741 /* Handler for QUIT - exec "restart" action,
742 * else (no such action defined) do nothing */
743 static void restart_handler(int sig UNUSED_PARAM)
745 struct init_action *a;
747 for (a = init_action_list; a; a = a->next) {
748 if (!(a->action_type & RESTART))
751 /* Starting from here, we won't return.
752 * Thus don't need to worry about preserving errno
755 kill_all_processes();
756 open_stdio_to_tty(a->terminal, 0 /* - halt if open fails */);
757 messageD(L_CONSOLE, "Trying to re-exec %s", a->command);
758 init_exec(a->command);
759 low_level_reboot(RB_HALT_SYSTEM);
764 #if ENABLE_FEATURE_USE_INITTAB
765 static void reload_inittab(void)
767 struct init_action *a, *tmp;
769 message(L_LOG, "reloading /etc/inittab");
771 /* Disable old entries */
772 for (a = init_action_list; a; a = a->next) {
773 a->action_type = ONCE;
778 if (ENABLE_FEATURE_KILL_REMOVED) {
779 /* Be nice and send SIGTERM first */
780 for (a = init_action_list; a; a = a->next)
782 kill(a->pid, SIGTERM);
783 if (CONFIG_FEATURE_KILL_DELAY) {
784 /* NB: parent will wait in NOMMU case */
785 if ((BB_MMU ? fork() : vfork()) == 0) { /* child */
786 sleep(CONFIG_FEATURE_KILL_DELAY);
787 for (a = init_action_list; a; a = a->next)
789 kill(a->pid, SIGKILL);
795 /* Remove old and unused entries */
796 for (a = init_action_list; a; a = tmp) {
798 if (a->action_type & (ONCE | SYSINIT | WAIT))
799 delete_init_action(a);
802 /* run_actions(RESPAWN | ASKFIRST); */
803 /* - we return to main loop, which does this automagically */
807 static int check_delayed_sigs(void)
812 smallint sig = bb_got_signal;
818 #if ENABLE_FEATURE_USE_INITTAB
823 run_actions(CTRLALTDEL);
827 int init_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
828 int init_main(int argc UNUSED_PARAM, char **argv)
830 die_sleep = 30 * 24*60*60; /* if xmalloc would ever die... */
832 if (argv[1] && !strcmp(argv[1], "-q")) {
833 return kill(1, SIGHUP);
837 /* Expect to be invoked as init with PID=1 or be invoked as linuxrc */
839 && (!ENABLE_FEATURE_INITRD || !strstr(applet_name, "linuxrc"))
843 /* Turn off rebooting via CTL-ALT-DEL - we get a
844 * SIGINT on CAD so we can shut things down gracefully... */
845 reboot(RB_DISABLE_CAD); /* misnomer */
848 /* Figure out where the default console should be */
854 /* Make sure environs is set to something sane */
855 putenv((char *) "HOME=/");
856 putenv((char *) bb_PATH_root_path);
857 putenv((char *) "SHELL=/bin/sh");
858 putenv((char *) "USER=root"); /* needed? why? */
861 xsetenv("RUNLEVEL", argv[1]);
864 message(MAYBE_CONSOLE | L_LOG, "init started: %s", bb_banner);
866 /* Make sure there is enough memory to do something useful. */
867 if (ENABLE_SWAPONOFF) {
870 if (sysinfo(&info) == 0
871 && (info.mem_unit ? : 1) * (long long)info.totalram < 1024*1024
873 message(L_CONSOLE, "Low memory, forcing swapon");
874 /* swapon -a requires /proc typically */
875 new_init_action(SYSINIT, "mount -t proc proc /proc", "");
876 /* Try to turn on swap */
877 new_init_action(SYSINIT, "swapon -a", "");
878 run_actions(SYSINIT); /* wait and removing */
882 /* Check if we are supposed to be in single user mode */
884 && (!strcmp(argv[1], "single") || !strcmp(argv[1], "-s") || LONE_CHAR(argv[1], '1'))
886 /* ??? shouldn't we set RUNLEVEL="b" here? */
887 /* Start a shell on console */
888 new_init_action(RESPAWN, bb_default_login_shell, "");
890 /* Not in single user mode - see what inittab says */
892 /* NOTE that if CONFIG_FEATURE_USE_INITTAB is NOT defined,
893 * then parse_inittab() simply adds in some default
894 * actions(i.e., INIT_SCRIPT and a pair
895 * of "askfirst" shells */
900 if (getenv("SELINUX_INIT") == NULL) {
903 putenv((char*)"SELINUX_INIT=YES");
904 if (selinux_init_load_policy(&enforce) == 0) {
905 BB_EXECVP(argv[0], argv);
906 } else if (enforce > 0) {
907 /* SELinux in enforcing mode but load_policy failed */
908 message(L_CONSOLE, "cannot load SELinux Policy. "
909 "Machine is in enforcing mode. Halting now.");
915 /* Make the command line just say "init" - thats all, nothing else */
916 strncpy(argv[0], "init", strlen(argv[0]));
917 /* Wipe argv[1]-argv[N] so they don't clutter the ps listing */
919 memset(*argv, 0, strlen(*argv));
921 /* Set up signal handlers */
926 + (1 << SIGUSR1) /* halt */
927 + (1 << SIGTERM) /* reboot */
928 + (1 << SIGUSR2) /* poweroff */
929 , halt_reboot_pwoff);
930 signal(SIGQUIT, restart_handler); /* re-exec another init */
932 /* Stop handler must allow only SIGCONT inside itself */
933 memset(&sa, 0, sizeof(sa));
934 sigfillset(&sa.sa_mask);
935 sigdelset(&sa.sa_mask, SIGCONT);
936 sa.sa_handler = stop_handler;
937 /* NB: sa_flags doesn't have SA_RESTART.
938 * It must be able to interrupt wait().
940 sigaction_set(SIGTSTP, &sa); /* pause */
941 /* Does not work as intended, at least in 2.6.20.
942 * SIGSTOP is simply ignored by init:
944 sigaction_set(SIGSTOP, &sa); /* pause */
946 /* SIGINT (Ctrl-Alt-Del) must interrupt wait(),
947 * setting handler without SA_RESTART flag.
949 bb_signals_recursive_norestart((1 << SIGINT), record_signo);
952 /* Now run everything that needs to be run */
953 /* First run the sysinit command */
954 run_actions(SYSINIT);
955 check_delayed_sigs();
956 /* Next run anything that wants to block */
958 check_delayed_sigs();
959 /* Next run anything to be run only once */
962 /* Set up "reread /etc/inittab" handler.
963 * Handler is set up without SA_RESTART, it will interrupt syscalls.
965 if (!DEBUG_INIT && ENABLE_FEATURE_USE_INITTAB)
966 bb_signals_recursive_norestart((1 << SIGHUP), record_signo);
968 /* Now run the looping stuff for the rest of forever.
969 * NB: if delayed signal happened, avoid blocking in wait().
975 got_sigs = check_delayed_sigs();
977 /* (Re)run the respawn/askfirst stuff */
978 run_actions(RESPAWN | ASKFIRST);
980 got_sigs |= check_delayed_sigs();
982 /* Don't consume all CPU time - sleep a bit */
985 got_sigs |= check_delayed_sigs();
987 /* Wait for any child process to exit.
988 * NB: "delayed" signals will also interrupt this wait(),
989 * bb_signals_recursive_norestart() set them up for that.
990 * This guarantees we won't be stuck here
991 * till next orphan dies.
997 struct init_action *a = mark_terminated(wpid);
999 message(L_LOG, "process '%s' (pid %d) exited. "
1000 "Scheduling for restart.",
1003 /* See if anyone else is waiting to be reaped */
1005 wpid = wait_any_nohang(NULL);