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.
14 #include <sys/reboot.h>
15 #include <sys/syslog.h>
17 #define INIT_BUFFS_SIZE 256
18 #define CONSOLE_NAME_SIZE 32
19 #define MAXENV 16 /* Number of env. vars */
22 * When a file named CORE_ENABLE_FLAG_FILE exists, setrlimit is called
23 * before processes are spawned to set core file size as unlimited.
24 * This is for debugging only. Don't use this is production, unless
25 * you want core dumps lying about....
27 #define CORE_ENABLE_FLAG_FILE "/.init_enable_core"
28 #include <sys/resource.h>
30 #define INITTAB "/etc/inittab" /* inittab file location */
32 #define INIT_SCRIPT "/etc/init.d/rcS" /* Default sysinit script. */
35 /* Allowed init action types */
38 #define ASKFIRST 0x004
41 #define CTRLALTDEL 0x020
42 #define SHUTDOWN 0x040
45 #define STR_SYSINIT "\x01"
46 #define STR_RESPAWN "\x02"
47 #define STR_ASKFIRST "\x04"
48 #define STR_WAIT "\x08"
49 #define STR_ONCE "\x10"
50 #define STR_CTRLALTDEL "\x20"
51 #define STR_SHUTDOWN "\x40"
52 #define STR_RESTART "\x80"
54 /* Set up a linked list of init_actions, to be read from inittab */
56 struct init_action *next;
59 char terminal[CONSOLE_NAME_SIZE];
60 char command[INIT_BUFFS_SIZE];
63 /* Static variables */
64 static struct init_action *init_action_list = NULL;
66 static const char *log_console = VC_5;
67 static sig_atomic_t got_cont = 0;
73 #if ENABLE_FEATURE_EXTRA_QUIET
76 MAYBE_CONSOLE = L_CONSOLE,
79 #ifndef RB_HALT_SYSTEM
80 RB_HALT_SYSTEM = 0xcdef0123, /* FIXME: this overflows enum */
81 RB_ENABLE_CAD = 0x89abcdef,
83 RB_POWER_OFF = 0x4321fedc,
84 RB_AUTOBOOT = 0x01234567,
88 static const char *const environment[] = {
96 /* Function prototypes */
97 static void delete_init_action(struct init_action *a);
98 static void halt_reboot_pwoff(int sig) ATTRIBUTE_NORETURN;
100 static void waitfor(pid_t pid)
102 /* waitfor(run(x)): protect against failed fork inside run() */
106 /* Wait for any child (prevent zombies from exiting orphaned processes)
107 * but exit the loop only when specified one has exited. */
108 while (wait(NULL) != pid)
112 static void loop_forever(void) ATTRIBUTE_NORETURN;
113 static void loop_forever(void)
119 /* Print a message to the specified device.
120 * Device may be bitwise-or'd from L_LOG | L_CONSOLE */
121 #define messageD(...) do { if (ENABLE_DEBUG_INIT) message(__VA_ARGS__); } while (0)
122 static void message(int device, const char *fmt, ...)
123 __attribute__ ((format(printf, 2, 3)));
124 static void message(int device, const char *fmt, ...)
126 static int log_fd = -1;
132 va_start(arguments, fmt);
133 vsnprintf(msg + 1, sizeof(msg) - 2, fmt, arguments);
135 msg[sizeof(msg) - 2] = '\0';
138 if (ENABLE_FEATURE_INIT_SYSLOG) {
139 /* Log the message to syslogd */
140 if (device & L_LOG) {
142 openlog(applet_name, 0, LOG_DAEMON);
143 syslog(LOG_INFO, "init: %s", msg + 1);
151 /* Take full control of the log tty, and never close it.
152 * It's mine, all mine! Muhahahaha! */
157 log_fd = device_open(log_console, O_WRONLY | O_NONBLOCK | O_NOCTTY);
159 bb_error_msg("can't log to %s", log_console);
162 close_on_exec_on(log_fd);
166 if (device & L_LOG) {
167 full_write(log_fd, msg, l);
169 return; /* don't print dup messages */
173 if (device & L_CONSOLE) {
174 /* Send console messages to console so people will see them. */
175 full_write(2, msg, l);
179 /* From <linux/serial.h> */
180 struct serial_struct {
189 unsigned short close_delay;
191 char reserved_char[1];
193 unsigned short closing_wait; /* time to wait before closing */
194 unsigned short closing_wait2; /* no longer used... */
195 unsigned char *iomem_base;
196 unsigned short iomem_reg_shift;
197 unsigned int port_high;
198 unsigned long iomap_base; /* cookie passed into ioremap */
200 /* Paranoia (imagine 64bit kernel overwriting 32bit userspace stack) */
201 uint32_t bbox_reserved[16];
203 static void console_init(void)
205 struct serial_struct sr;
208 s = getenv("CONSOLE");
209 if (!s) s = getenv("console");
211 int fd = open(s, O_RDWR | O_NONBLOCK | O_NOCTTY);
216 while (fd > 2) close(fd--);
218 messageD(L_LOG, "console='%s'", s);
220 /* Make sure fd 0,1,2 are not closed */
225 if (ioctl(0, TIOCGSERIAL, &sr) == 0) {
226 /* Force the TERM setting to vt102 for serial console
227 * if TERM is set to linux (the default) */
228 if (!s || strcmp(s, "linux") == 0)
229 putenv((char*)"TERM=vt102");
230 if (!ENABLE_FEATURE_INIT_SYSLOG)
233 putenv((char*)"TERM=linux");
236 /* Set terminal settings to reasonable defaults */
237 static void set_sane_term(void)
241 tcgetattr(STDIN_FILENO, &tty);
243 /* set control chars */
244 tty.c_cc[VINTR] = 3; /* C-c */
245 tty.c_cc[VQUIT] = 28; /* C-\ */
246 tty.c_cc[VERASE] = 127; /* C-? */
247 tty.c_cc[VKILL] = 21; /* C-u */
248 tty.c_cc[VEOF] = 4; /* C-d */
249 tty.c_cc[VSTART] = 17; /* C-q */
250 tty.c_cc[VSTOP] = 19; /* C-s */
251 tty.c_cc[VSUSP] = 26; /* C-z */
253 /* use line dicipline 0 */
256 /* Make it be sane */
257 tty.c_cflag &= CBAUD | CBAUDEX | CSIZE | CSTOPB | PARENB | PARODD;
258 tty.c_cflag |= CREAD | HUPCL | CLOCAL;
261 tty.c_iflag = ICRNL | IXON | IXOFF;
264 tty.c_oflag = OPOST | ONLCR;
268 ISIG | ICANON | ECHO | ECHOE | ECHOK | ECHOCTL | ECHOKE | IEXTEN;
270 tcsetattr(STDIN_FILENO, TCSANOW, &tty);
273 /* Open the new terminal device */
274 static void open_stdio_to_tty(const char* tty_name, int exit_on_failure)
276 /* empty tty_name means "use init's tty", else... */
280 /* fd can be only < 0 or 0: */
281 fd = device_open(tty_name, O_RDWR);
283 message(L_LOG | L_CONSOLE, "Can't open %s: %s",
284 tty_name, strerror(errno));
287 if (ENABLE_DEBUG_INIT)
289 halt_reboot_pwoff(SIGUSR1); /* halt the system */
297 /* Used only by run_actions */
298 static pid_t run(const struct init_action *a)
302 char *s, *tmpCmd, *cmdpath;
303 char *cmd[INIT_BUFFS_SIZE];
304 char buf[INIT_BUFFS_SIZE + 6]; /* INIT_BUFFS_SIZE+strlen("exec ")+1 */
305 sigset_t nmask, omask;
307 /* Block sigchild while forking (why?) */
309 sigaddset(&nmask, SIGCHLD);
310 sigprocmask(SIG_BLOCK, &nmask, &omask);
312 sigprocmask(SIG_SETMASK, &omask, NULL);
315 message(L_LOG | L_CONSOLE, "Can't fork");
321 /* Reset signal handlers that were set by the parent process */
322 signal(SIGUSR1, SIG_DFL);
323 signal(SIGUSR2, SIG_DFL);
324 signal(SIGINT, SIG_DFL);
325 signal(SIGTERM, SIG_DFL);
326 signal(SIGHUP, SIG_DFL);
327 signal(SIGQUIT, SIG_DFL);
328 signal(SIGCONT, SIG_DFL);
329 signal(SIGSTOP, SIG_DFL);
330 signal(SIGTSTP, SIG_DFL);
332 /* Create a new session and make ourself the process
336 /* Open the new terminal device */
337 open_stdio_to_tty(a->terminal, 1 /* - exit if open fails*/);
339 #ifdef BUT_RUN_ACTIONS_ALREADY_DOES_WAITING
340 /* If the init Action requires us to wait, then force the
341 * supplied terminal to be the controlling tty. */
342 if (a->action & (SYSINIT | WAIT | CTRLALTDEL | SHUTDOWN | RESTART)) {
343 /* Now fork off another process to just hang around */
346 message(L_LOG | L_CONSOLE, "Can't fork");
351 /* Parent - wait till the child is done */
352 signal(SIGINT, SIG_IGN);
353 signal(SIGTSTP, SIG_IGN);
354 signal(SIGQUIT, SIG_IGN);
355 signal(SIGCHLD, SIG_DFL);
358 /* See if stealing the controlling tty back is necessary */
359 if (tcgetpgrp(0) != getpid())
362 /* Use a temporary process to steal the controlling tty. */
365 message(L_LOG | L_CONSOLE, "Can't fork");
370 ioctl(0, TIOCSCTTY, 1);
377 /* Child - fall though to actually execute things */
381 /* See if any special /bin/sh requiring characters are present */
382 if (strpbrk(a->command, "~`!$^&*()=|\\{}[];\"'<>?") != NULL) {
383 cmd[0] = (char*)DEFAULT_SHELL;
384 cmd[1] = (char*)"-c";
385 cmd[2] = strcat(strcpy(buf, "exec "), a->command);
388 /* Convert command (char*) into cmd (char**, one word per string) */
389 strcpy(buf, a->command);
391 for (tmpCmd = buf, i = 0; (tmpCmd = strsep(&s, " \t")) != NULL;) {
392 if (*tmpCmd != '\0') {
403 * Interactive shells want to see a dash in argv[0]. This
404 * typically is handled by login, argv will be setup this
405 * way if a dash appears at the front of the command path
408 if (*cmdpath == '-') {
409 /* skip over the dash */
412 #ifdef WHY_WE_DO_THIS_SHELL_MUST_HANDLE_THIS_ITSELF
413 /* find the last component in the command pathname */
414 s = bb_get_last_path_component_nostrip(cmdpath);
415 /* make a new argv[0] */
416 cmd[0] = malloc(strlen(s) + 2);
417 if (cmd[0] == NULL) {
418 message(L_LOG | L_CONSOLE, bb_msg_memory_exhausted);
422 strcpy(cmd[0] + 1, s);
426 /* _Attempt_ to make stdin a controlling tty. */
427 if (ENABLE_FEATURE_INIT_SCTTY)
428 ioctl(0, TIOCSCTTY, 0 /*only try, don't steal*/);
431 if (a->action & ASKFIRST) {
432 static const char press_enter[] ALIGN1 =
433 #ifdef CUSTOMIZED_BANNER
434 #include CUSTOMIZED_BANNER
436 "\nPlease press Enter to activate this console. ";
439 * Save memory by not exec-ing anything large (like a shell)
440 * before the user wants it. This is critical if swap is not
441 * enabled and the system has low memory. Generally this will
442 * be run on the second virtual console, and the first will
443 * be allowed to start a shell or whatever an init script
446 messageD(L_LOG, "waiting for enter to start '%s'"
447 "(pid %d, tty '%s')\n",
448 cmdpath, getpid(), a->terminal);
449 full_write(1, press_enter, sizeof(press_enter) - 1);
450 while (safe_read(0, &c, 1) == 1 && c != '\n')
454 /* Log the process name and args */
455 message(L_LOG, "starting pid %d, tty '%s': '%s'",
456 getpid(), a->terminal, cmdpath);
458 if (ENABLE_FEATURE_INIT_COREDUMPS) {
460 if (stat(CORE_ENABLE_FLAG_FILE, &sb) == 0) {
463 limit.rlim_cur = RLIM_INFINITY;
464 limit.rlim_max = RLIM_INFINITY;
465 setrlimit(RLIMIT_CORE, &limit);
469 /* Now run it. The new program will take over this PID,
470 * so nothing further in init.c should be run. */
471 BB_EXECVP(cmdpath, cmd);
473 /* We're still here? Some error happened. */
474 message(L_LOG | L_CONSOLE, "Cannot run '%s': %s",
475 cmdpath, strerror(errno));
479 /* Run all commands of a particular type */
480 static void run_actions(int action)
482 struct init_action *a, *tmp;
484 for (a = init_action_list; a; a = tmp) {
486 if (a->action == action) {
487 // Pointless: run() will error out if open of device fails.
488 ///* a->terminal of "" means "init's console" */
489 //if (a->terminal[0] && access(a->terminal, R_OK | W_OK)) {
490 // //message(L_LOG | L_CONSOLE, "Device %s cannot be opened in RW mode", a->terminal /*, strerror(errno)*/);
491 // delete_init_action(a);
493 if (a->action & (SYSINIT | WAIT | CTRLALTDEL | SHUTDOWN | RESTART)) {
495 delete_init_action(a);
496 } else if (a->action & ONCE) {
498 delete_init_action(a);
499 } else if (a->action & (RESPAWN | ASKFIRST)) {
500 /* Only run stuff with pid==0. If they have
501 * a pid, that means it is still running */
510 static void init_reboot(unsigned long magic)
513 /* We have to fork here, since the kernel calls do_exit(0) in
514 * linux/kernel/sys.c, which can cause the machine to panic when
515 * the init process is killed.... */
517 if (pid == 0) { /* child */
524 static void kill_all_processes(void)
526 sigset_t block_signals;
528 /* run everything to be run at "shutdown". This is done _prior_
529 * to killing everything, in case people wish to use scripts to
530 * shut things down gracefully... */
531 run_actions(SHUTDOWN);
533 /* first disable all our signals */
534 sigfillset(&block_signals);
535 /*sigemptyset(&block_signals);
536 sigaddset(&block_signals, SIGHUP);
537 sigaddset(&block_signals, SIGQUIT);
538 sigaddset(&block_signals, SIGCHLD);
539 sigaddset(&block_signals, SIGUSR1);
540 sigaddset(&block_signals, SIGUSR2);
541 sigaddset(&block_signals, SIGINT);
542 sigaddset(&block_signals, SIGTERM);
543 sigaddset(&block_signals, SIGCONT);
544 sigaddset(&block_signals, SIGSTOP);
545 sigaddset(&block_signals, SIGTSTP);*/
546 sigprocmask(SIG_BLOCK, &block_signals, NULL);
548 message(L_CONSOLE | L_LOG, "The system is going down NOW!");
550 /* Allow Ctrl-Alt-Del to reboot system. */
551 init_reboot(RB_ENABLE_CAD);
553 /* Send signals to every process _except_ pid 1 */
554 message(L_CONSOLE | L_LOG, "Sending SIG%s to all processes", "TERM");
559 message(L_CONSOLE | L_LOG, "Sending SIG%s to all processes", "KILL");
565 static void halt_reboot_pwoff(int sig)
570 kill_all_processes();
574 if (sig == SIGTERM) {
577 } else if (sig == SIGUSR2) {
581 message(L_CONSOLE | L_LOG, "Requesting system %s", m);
582 /* allow time for last message to reach serial console */
588 /* Handler for HUP and QUIT - exec "restart" action,
589 * else (no such action defined) do nothing */
590 static void exec_restart_action(int sig ATTRIBUTE_UNUSED)
592 struct init_action *a, *tmp;
593 sigset_t unblock_signals;
595 for (a = init_action_list; a; a = tmp) {
597 if (a->action & RESTART) {
598 kill_all_processes();
600 /* unblock all signals (blocked in kill_all_processes()) */
601 sigfillset(&unblock_signals);
602 /*sigemptyset(&unblock_signals);
603 sigaddset(&unblock_signals, SIGHUP);
604 sigaddset(&unblock_signals, SIGQUIT);
605 sigaddset(&unblock_signals, SIGCHLD);
606 sigaddset(&unblock_signals, SIGUSR1);
607 sigaddset(&unblock_signals, SIGUSR2);
608 sigaddset(&unblock_signals, SIGINT);
609 sigaddset(&unblock_signals, SIGTERM);
610 sigaddset(&unblock_signals, SIGCONT);
611 sigaddset(&unblock_signals, SIGSTOP);
612 sigaddset(&unblock_signals, SIGTSTP);*/
613 sigprocmask(SIG_UNBLOCK, &unblock_signals, NULL);
615 /* Open the new terminal device */
616 open_stdio_to_tty(a->terminal, 0 /* - halt if open fails */);
618 messageD(L_CONSOLE | L_LOG, "Trying to re-exec %s", a->command);
619 BB_EXECLP(a->command, a->command, NULL);
621 message(L_CONSOLE | L_LOG, "Cannot run '%s': %s",
622 a->command, strerror(errno));
624 init_reboot(RB_HALT_SYSTEM);
630 static void ctrlaltdel_signal(int sig ATTRIBUTE_UNUSED)
632 run_actions(CTRLALTDEL);
635 /* The SIGSTOP & SIGTSTP handler */
636 static void stop_handler(int sig ATTRIBUTE_UNUSED)
638 int saved_errno = errno;
647 /* The SIGCONT handler */
648 static void cont_handler(int sig ATTRIBUTE_UNUSED)
653 static void new_init_action(uint8_t action, const char *command, const char *cons)
655 struct init_action *new_action, *a, *last;
657 if (strcmp(cons, bb_dev_null) == 0 && (action & ASKFIRST))
660 /* Append to the end of the list */
661 for (a = last = init_action_list; a; a = a->next) {
662 /* don't enter action if it's already in the list,
663 * but do overwrite existing actions */
664 if ((strcmp(a->command, command) == 0)
665 && (strcmp(a->terminal, cons) == 0)
673 new_action = xzalloc(sizeof(struct init_action));
675 last->next = new_action;
677 init_action_list = new_action;
679 strcpy(new_action->command, command);
680 new_action->action = action;
681 strcpy(new_action->terminal, cons);
682 messageD(L_LOG | L_CONSOLE, "command='%s' action=%d tty='%s'\n",
683 new_action->command, new_action->action, new_action->terminal);
686 static void delete_init_action(struct init_action *action)
688 struct init_action *a, *b = NULL;
690 for (a = init_action_list; a; b = a, a = a->next) {
693 init_action_list = a->next;
703 /* NOTE that if CONFIG_FEATURE_USE_INITTAB is NOT defined,
704 * then parse_inittab() simply adds in some default
705 * actions(i.e., runs INIT_SCRIPT and then starts a pair
706 * of "askfirst" shells). If CONFIG_FEATURE_USE_INITTAB
707 * _is_ defined, but /etc/inittab is missing, this
708 * results in the same set of default behaviors.
710 static void parse_inittab(void)
713 char buf[INIT_BUFFS_SIZE];
715 if (ENABLE_FEATURE_USE_INITTAB)
716 file = fopen(INITTAB, "r");
720 /* No inittab file -- set up some default behavior */
722 /* Reboot on Ctrl-Alt-Del */
723 new_init_action(CTRLALTDEL, "reboot", "");
724 /* Umount all filesystems on halt/reboot */
725 new_init_action(SHUTDOWN, "umount -a -r", "");
726 /* Swapoff on halt/reboot */
727 if (ENABLE_SWAPONOFF)
728 new_init_action(SHUTDOWN, "swapoff -a", "");
729 /* Prepare to restart init when a HUP is received */
730 new_init_action(RESTART, "init", "");
731 /* Askfirst shell on tty1-4 */
732 new_init_action(ASKFIRST, bb_default_login_shell, "");
733 new_init_action(ASKFIRST, bb_default_login_shell, VC_2);
734 new_init_action(ASKFIRST, bb_default_login_shell, VC_3);
735 new_init_action(ASKFIRST, bb_default_login_shell, VC_4);
737 new_init_action(SYSINIT, INIT_SCRIPT, "");
742 while (fgets(buf, INIT_BUFFS_SIZE, file) != NULL) {
743 static const char actions[] =
744 STR_SYSINIT "sysinit\0"
745 STR_RESPAWN "respawn\0"
746 STR_ASKFIRST "askfirst\0"
749 STR_CTRLALTDEL "ctrlaltdel\0"
750 STR_SHUTDOWN "shutdown\0"
751 STR_RESTART "restart\0"
753 char tmpConsole[CONSOLE_NAME_SIZE];
754 char *id, *runlev, *action, *command;
757 /* Skip leading spaces */
758 id = skip_whitespace(buf);
759 /* Skip the line if it's a comment */
760 if (*id == '#' || *id == '\n')
762 /* Trim the trailing '\n' */
763 *strchrnul(id, '\n') = '\0';
765 /* Line is: "id:runlevel_ignored:action:command" */
766 runlev = strchr(id, ':');
767 if (runlev == NULL /*|| runlev[1] == '\0' - not needed */)
769 action = strchr(runlev + 1, ':');
770 if (action == NULL /*|| action[1] == '\0' - not needed */)
772 command = strchr(action + 1, ':');
773 if (command == NULL || command[1] == '\0')
776 *command = '\0'; /* action => ":action\0" now */
777 for (a = actions; a[0]; a += strlen(a) + 1) {
778 if (strcmp(a + 1, action + 1) == 0) {
781 if (strncmp(id, "/dev/", 5) == 0)
783 strcpy(tmpConsole, "/dev/");
784 safe_strncpy(tmpConsole + 5, id,
785 sizeof(tmpConsole) - 5);
788 new_init_action((uint8_t)a[0], command + 1, id);
793 /* Choke on an unknown action */
795 message(L_LOG | L_CONSOLE, "Bad inittab entry: %s", id);
801 static void reload_signal(int sig ATTRIBUTE_UNUSED)
803 struct init_action *a, *tmp;
805 message(L_LOG, "reloading /etc/inittab");
807 /* disable old entrys */
808 for (a = init_action_list; a; a = a->next) {
814 if (ENABLE_FEATURE_KILL_REMOVED) {
815 /* Be nice and send SIGTERM first */
816 for (a = init_action_list; a; a = a->next) {
818 if ((a->action & ONCE) && pid != 0) {
822 #if CONFIG_FEATURE_KILL_DELAY
823 if (fork() == 0) { /* child */
824 sleep(CONFIG_FEATURE_KILL_DELAY);
825 for (a = init_action_list; a; a = a->next) {
827 if ((a->action & ONCE) && pid != 0) {
836 /* remove unused entrys */
837 for (a = init_action_list; a; a = tmp) {
839 if ((a->action & (ONCE | SYSINIT | WAIT)) && a->pid == 0) {
840 delete_init_action(a);
843 run_actions(RESPAWN);
846 int init_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
847 int init_main(int argc, char **argv)
849 struct init_action *a;
852 die_sleep = 30 * 24*60*60; /* if xmalloc will ever die... */
854 if (argc > 1 && !strcmp(argv[1], "-q")) {
855 return kill(1, SIGHUP);
858 if (!ENABLE_DEBUG_INIT) {
859 /* Expect to be invoked as init with PID=1 or be invoked as linuxrc */
861 && (!ENABLE_FEATURE_INITRD || !strstr(applet_name, "linuxrc"))
865 /* Set up sig handlers -- be sure to
866 * clear all of these in run() */
867 signal(SIGHUP, exec_restart_action);
868 signal(SIGQUIT, exec_restart_action);
869 signal(SIGUSR1, halt_reboot_pwoff); /* halt */
870 signal(SIGUSR2, halt_reboot_pwoff); /* poweroff */
871 signal(SIGTERM, halt_reboot_pwoff); /* reboot */
872 signal(SIGINT, ctrlaltdel_signal);
873 signal(SIGCONT, cont_handler);
874 signal(SIGSTOP, stop_handler);
875 signal(SIGTSTP, stop_handler);
877 /* Turn off rebooting via CTL-ALT-DEL -- we get a
878 * SIGINT on CAD so we can shut things down gracefully... */
879 init_reboot(RB_DISABLE_CAD);
882 /* Figure out where the default console should be */
888 const char *const *e;
889 /* Make sure environs is set to something sane */
890 for (e = environment; *e; e++)
894 if (argc > 1) setenv("RUNLEVEL", argv[1], 1);
897 message(MAYBE_CONSOLE | L_LOG, "init started: %s", bb_banner);
899 /* Make sure there is enough memory to do something useful. */
900 if (ENABLE_SWAPONOFF) {
903 if (!sysinfo(&info) &&
904 (info.mem_unit ? : 1) * (long long)info.totalram < 1024*1024)
906 message(L_CONSOLE, "Low memory, forcing swapon");
907 /* swapon -a requires /proc typically */
908 new_init_action(SYSINIT, "mount -t proc proc /proc", "");
909 /* Try to turn on swap */
910 new_init_action(SYSINIT, "swapon -a", "");
911 run_actions(SYSINIT); /* wait and removing */
915 /* Check if we are supposed to be in single user mode */
917 && (!strcmp(argv[1], "single") || !strcmp(argv[1], "-s") || LONE_CHAR(argv[1], '1'))
919 /* Start a shell on console */
920 new_init_action(RESPAWN, bb_default_login_shell, "");
922 /* Not in single user mode -- see what inittab says */
924 /* NOTE that if CONFIG_FEATURE_USE_INITTAB is NOT defined,
925 * then parse_inittab() simply adds in some default
926 * actions(i.e., runs INIT_SCRIPT and then starts a pair
927 * of "askfirst" shells */
932 if (getenv("SELINUX_INIT") == NULL) {
935 putenv((char*)"SELINUX_INIT=YES");
936 if (selinux_init_load_policy(&enforce) == 0) {
937 BB_EXECVP(argv[0], argv);
938 } else if (enforce > 0) {
939 /* SELinux in enforcing mode but load_policy failed */
940 message(L_CONSOLE, "Cannot load SELinux Policy. "
941 "Machine is in enforcing mode. Halting now.");
945 #endif /* CONFIG_SELINUX */
947 /* Make the command line just say "init" - thats all, nothing else */
948 strncpy(argv[0], "init", strlen(argv[0]));
949 /* Wipe argv[1]-argv[N] so they don't clutter the ps listing */
951 memset(*argv, 0, strlen(*argv));
953 /* Now run everything that needs to be run */
955 /* First run the sysinit command */
956 run_actions(SYSINIT);
958 /* Next run anything that wants to block */
961 /* Next run anything to be run only once */
964 /* Redefine SIGHUP to reread /etc/inittab */
965 if (ENABLE_FEATURE_USE_INITTAB)
966 signal(SIGHUP, reload_signal);
968 signal(SIGHUP, SIG_IGN);
970 /* Now run the looping stuff for the rest of forever */
972 /* run the respawn stuff */
973 run_actions(RESPAWN);
975 /* run the askfirst stuff */
976 run_actions(ASKFIRST);
978 /* Don't consume all CPU time -- sleep a bit */
981 /* Wait for any child process to exit */
984 /* Find out who died and clean up their corpse */
985 for (a = init_action_list; a; a = a->next) {
986 if (a->pid == wpid) {
987 /* Set the pid to 0 so that the process gets
988 * restarted by run_actions() */
990 message(L_LOG, "process '%s' (pid %d) exited. "
991 "Scheduling it for restart.",
995 /* see if anyone else is waiting to be reaped */
996 wpid = wait_any_nohang(NULL);