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/ioctl.h>
16 //#include <sys/wait.h>
17 #include <sys/reboot.h>
19 #if ENABLE_FEATURE_INIT_SYSLOG
20 # include <sys/syslog.h>
23 #define INIT_BUFFS_SIZE 256
24 #define CONSOLE_NAME_SIZE 32
25 #define MAXENV 16 /* Number of env. vars */
27 #if ENABLE_FEATURE_INIT_COREDUMPS
29 * When a file named CORE_ENABLE_FLAG_FILE exists, setrlimit is called
30 * before processes are spawned to set core file size as unlimited.
31 * This is for debugging only. Don't use this is production, unless
32 * you want core dumps lying about....
34 #define CORE_ENABLE_FLAG_FILE "/.init_enable_core"
35 #include <sys/resource.h>
38 #define INITTAB "/etc/inittab" /* inittab file location */
40 #define INIT_SCRIPT "/etc/init.d/rcS" /* Default sysinit script. */
43 /* Allowed init action types */
46 #define ASKFIRST 0x004
49 #define CTRLALTDEL 0x020
50 #define SHUTDOWN 0x040
53 /* A mapping between "inittab" action name strings and action type codes. */
54 struct init_action_type {
59 static const struct init_action_type actions[] = {
62 {"askfirst", ASKFIRST},
65 {"ctrlaltdel", CTRLALTDEL},
66 {"shutdown", SHUTDOWN},
71 /* Set up a linked list of init_actions, to be read from inittab */
73 struct init_action *next;
76 char command[INIT_BUFFS_SIZE];
77 char terminal[CONSOLE_NAME_SIZE];
80 /* Static variables */
81 static struct init_action *init_action_list = NULL;
83 #if !ENABLE_FEATURE_INIT_SYSLOG
84 static const char *log_console = VC_5;
86 #if !ENABLE_DEBUG_INIT
87 static sig_atomic_t got_cont = 0;
94 #if ENABLE_FEATURE_EXTRA_QUIET
97 MAYBE_CONSOLE = L_CONSOLE,
100 #ifndef RB_HALT_SYSTEM
101 RB_HALT_SYSTEM = 0xcdef0123, /* FIXME: this overflows enum */
102 RB_ENABLE_CAD = 0x89abcdef,
104 RB_POWER_OFF = 0x4321fedc,
105 RB_AUTOBOOT = 0x01234567,
109 static const char * const environment[] = {
117 /* Function prototypes */
118 static void delete_init_action(struct init_action *a);
119 static int waitfor(const struct init_action *a, pid_t pid);
120 #if !ENABLE_DEBUG_INIT
121 static void shutdown_signal(int sig);
124 #if !ENABLE_DEBUG_INIT
125 static void loop_forever(void)
132 /* Print a message to the specified device.
133 * Device may be bitwise-or'd from L_LOG | L_CONSOLE */
134 #if ENABLE_DEBUG_INIT
135 #define messageD message
137 #define messageD(...) do {} while (0)
139 static void message(int device, const char *fmt, ...)
140 __attribute__ ((format(printf, 2, 3)));
141 static void message(int device, const char *fmt, ...)
143 #if !ENABLE_FEATURE_INIT_SYSLOG
144 static int log_fd = -1;
152 va_start(arguments, fmt);
153 vsnprintf(msg + 1, sizeof(msg) - 2, fmt, arguments);
155 msg[sizeof(msg) - 2] = '\0';
158 #if ENABLE_FEATURE_INIT_SYSLOG
159 /* Log the message to syslogd */
160 if (device & L_LOG) {
162 openlog(applet_name, 0, LOG_DAEMON);
163 syslog(LOG_INFO, "init: %s", msg + 1);
171 /* Take full control of the log tty, and never close it.
172 * It's mine, all mine! Muhahahaha! */
177 log_fd = device_open(log_console, O_WRONLY | O_NONBLOCK | O_NOCTTY);
179 bb_error_msg("can't log to %s", log_console);
182 fcntl(log_fd, F_SETFD, FD_CLOEXEC);
186 if (device & L_LOG) {
187 full_write(log_fd, msg, l);
189 return; /* don't print dup messages */
193 if (device & L_CONSOLE) {
194 /* Send console messages to console so people will see them. */
195 full_write(2, msg, l);
199 /* Set terminal settings to reasonable defaults */
200 static void set_sane_term(void)
204 tcgetattr(STDIN_FILENO, &tty);
206 /* set control chars */
207 tty.c_cc[VINTR] = 3; /* C-c */
208 tty.c_cc[VQUIT] = 28; /* C-\ */
209 tty.c_cc[VERASE] = 127; /* C-? */
210 tty.c_cc[VKILL] = 21; /* C-u */
211 tty.c_cc[VEOF] = 4; /* C-d */
212 tty.c_cc[VSTART] = 17; /* C-q */
213 tty.c_cc[VSTOP] = 19; /* C-s */
214 tty.c_cc[VSUSP] = 26; /* C-z */
216 /* use line dicipline 0 */
219 /* Make it be sane */
220 tty.c_cflag &= CBAUD | CBAUDEX | CSIZE | CSTOPB | PARENB | PARODD;
221 tty.c_cflag |= CREAD | HUPCL | CLOCAL;
224 tty.c_iflag = ICRNL | IXON | IXOFF;
227 tty.c_oflag = OPOST | ONLCR;
231 ISIG | ICANON | ECHO | ECHOE | ECHOK | ECHOCTL | ECHOKE | IEXTEN;
233 tcsetattr(STDIN_FILENO, TCSANOW, &tty);
236 /* From <linux/serial.h> */
237 struct serial_struct {
246 unsigned short close_delay;
248 char reserved_char[1];
250 unsigned short closing_wait; /* time to wait before closing */
251 unsigned short closing_wait2; /* no longer used... */
252 unsigned char *iomem_base;
253 unsigned short iomem_reg_shift;
254 unsigned int port_high;
255 unsigned long iomap_base; /* cookie passed into ioremap */
257 /* Paranoia (imagine 64bit kernel overwriting 32bit userspace stack) */
258 uint32_t bbox_reserved[16];
260 static void console_init(void)
262 struct serial_struct sr;
265 s = getenv("CONSOLE");
266 if (!s) s = getenv("console");
268 int fd = open(s, O_RDWR | O_NONBLOCK | O_NOCTTY);
273 while (fd > 2) close(fd--);
275 messageD(L_LOG, "console='%s'", s);
279 if (ioctl(0, TIOCGSERIAL, &sr) == 0) {
280 /* Force the TERM setting to vt102 for serial console --
281 * if TERM is set to linux (the default) */
282 if (!s || strcmp(s, "linux") == 0)
283 putenv((char*)"TERM=vt102");
284 #if !ENABLE_FEATURE_INIT_SYSLOG
288 putenv((char*)"TERM=linux");
291 static void fixup_argv(int argc, char **argv, const char *new_argv0)
295 /* Fix up argv[0] to be certain we claim to be init */
296 len = strlen(argv[0]);
297 strncpy(argv[0], new_argv0, len);
299 /* Wipe argv[1]-argv[N] so they don't clutter the ps listing */
302 memset(argv[len], 0, strlen(argv[len]));
307 /* Open the new terminal device */
308 static void open_stdio_to_tty(const char* tty_name, int fail)
310 /* empty tty_name means "use init's tty", else... */
312 int fd = device_open(tty_name, O_RDWR);
314 message(L_LOG | L_CONSOLE, "Can't open %s: %s",
315 tty_name, strerror(errno));
318 #if !ENABLE_DEBUG_INIT
319 shutdown_signal(SIGUSR1);
327 if (fd > 2) close(fd);
333 static pid_t run(const struct init_action *a)
337 char *s, *tmpCmd, *cmdpath;
338 char *cmd[INIT_BUFFS_SIZE];
339 char buf[INIT_BUFFS_SIZE + 6]; /* INIT_BUFFS_SIZE+strlen("exec ")+1 */
340 sigset_t nmask, omask;
342 /* Block sigchild while forking. */
344 sigaddset(&nmask, SIGCHLD);
345 sigprocmask(SIG_BLOCK, &nmask, &omask);
347 sigprocmask(SIG_SETMASK, &omask, NULL);
352 /* Reset signal handlers that were set by the parent process */
353 signal(SIGUSR1, SIG_DFL);
354 signal(SIGUSR2, SIG_DFL);
355 signal(SIGINT, SIG_DFL);
356 signal(SIGTERM, SIG_DFL);
357 signal(SIGHUP, SIG_DFL);
358 signal(SIGQUIT, SIG_DFL);
359 signal(SIGCONT, SIG_DFL);
360 signal(SIGSTOP, SIG_DFL);
361 signal(SIGTSTP, SIG_DFL);
363 /* Create a new session and make ourself the process
367 /* Open the new terminal device */
368 open_stdio_to_tty(a->terminal, 1);
370 /* If the init Action requires us to wait, then force the
371 * supplied terminal to be the controlling tty. */
372 if (a->action & (SYSINIT | WAIT | CTRLALTDEL | SHUTDOWN | RESTART)) {
374 /* Now fork off another process to just hang around */
375 if ((pid = fork()) < 0) {
376 message(L_LOG | L_CONSOLE, "Can't fork");
382 /* We are the parent -- wait till the child is done */
383 signal(SIGINT, SIG_IGN);
384 signal(SIGTSTP, SIG_IGN);
385 signal(SIGQUIT, SIG_IGN);
386 signal(SIGCHLD, SIG_DFL);
389 /* See if stealing the controlling tty back is necessary */
390 if (tcgetpgrp(0) != getpid())
393 /* Use a temporary process to steal the controlling tty. */
394 if ((pid = fork()) < 0) {
395 message(L_LOG | L_CONSOLE, "Can't fork");
400 ioctl(0, TIOCSCTTY, 1);
407 /* Now fall though to actually execute things */
410 /* See if any special /bin/sh requiring characters are present */
411 if (strpbrk(a->command, "~`!$^&*()=|\\{}[];\"'<>?") != NULL) {
412 cmd[0] = (char*)DEFAULT_SHELL;
413 cmd[1] = (char*)"-c";
414 cmd[2] = strcat(strcpy(buf, "exec "), a->command);
417 /* Convert command (char*) into cmd (char**, one word per string) */
418 strcpy(buf, a->command);
420 for (tmpCmd = buf, i = 0; (tmpCmd = strsep(&s, " \t")) != NULL;) {
421 if (*tmpCmd != '\0') {
432 * Interactive shells want to see a dash in argv[0]. This
433 * typically is handled by login, argv will be setup this
434 * way if a dash appears at the front of the command path
437 if (*cmdpath == '-') {
438 /* skip over the dash */
441 /* find the last component in the command pathname */
442 s = bb_get_last_path_component(cmdpath);
444 /* make a new argv[0] */
445 if ((cmd[0] = malloc(strlen(s) + 2)) == NULL) {
446 message(L_LOG | L_CONSOLE, bb_msg_memory_exhausted);
450 strcpy(cmd[0] + 1, s);
452 #if ENABLE_FEATURE_INIT_SCTTY
453 /* Establish this process as session leader and
454 * (attempt) to make the tty (if any) a controlling tty.
457 ioctl(0, TIOCSCTTY, 0 /*don't steal it*/);
461 #if !defined(__UCLIBC__) || defined(__ARCH_HAS_MMU__)
462 if (a->action & ASKFIRST) {
463 static const char press_enter[] =
464 #ifdef CUSTOMIZED_BANNER
465 #include CUSTOMIZED_BANNER
467 "\nPlease press Enter to activate this console. ";
470 * Save memory by not exec-ing anything large (like a shell)
471 * before the user wants it. This is critical if swap is not
472 * enabled and the system has low memory. Generally this will
473 * be run on the second virtual console, and the first will
474 * be allowed to start a shell or whatever an init script
477 messageD(L_LOG, "waiting for enter to start '%s'"
478 "(pid %d, tty '%s')\n",
479 cmdpath, getpid(), a->terminal);
480 full_write(1, press_enter, sizeof(press_enter) - 1);
481 while (read(0, &c, 1) == 1 && c != '\n')
485 /* Log the process name and args */
486 message(L_LOG, "starting pid %d, tty '%s': '%s'",
487 getpid(), a->terminal, cmdpath);
489 #if ENABLE_FEATURE_INIT_COREDUMPS
492 if (stat(CORE_ENABLE_FLAG_FILE, &sb) == 0) {
495 limit.rlim_cur = RLIM_INFINITY;
496 limit.rlim_max = RLIM_INFINITY;
497 setrlimit(RLIMIT_CORE, &limit);
501 /* Now run it. The new program will take over this PID,
502 * so nothing further in init.c should be run. */
503 BB_EXECVP(cmdpath, cmd);
505 /* We're still here? Some error happened. */
506 message(L_LOG | L_CONSOLE, "Cannot run '%s': %s",
507 cmdpath, strerror(errno));
511 static int waitfor(const struct init_action *a, pid_t pid)
516 runpid = (NULL == a)? pid : run(a);
518 wpid = waitpid(runpid, &status, 0);
521 if (wpid == -1 && errno == ECHILD) {
522 /* we missed its termination */
525 /* FIXME other errors should maybe trigger an error, but allow
526 * the program to continue */
531 /* Run all commands of a particular type */
532 static void run_actions(int action)
534 struct init_action *a, *tmp;
536 for (a = init_action_list; a; a = tmp) {
538 if (a->action == action) {
539 /* a->terminal of "" means "init's console" */
540 if (a->terminal[0] && access(a->terminal, R_OK | W_OK)) {
541 delete_init_action(a);
542 } else if (a->action & (SYSINIT | WAIT | CTRLALTDEL | SHUTDOWN | RESTART)) {
544 delete_init_action(a);
545 } else if (a->action & ONCE) {
547 delete_init_action(a);
548 } else if (a->action & (RESPAWN | ASKFIRST)) {
549 /* Only run stuff with pid==0. If they have
550 * a pid, that means it is still running */
559 #if !ENABLE_DEBUG_INIT
560 static void init_reboot(unsigned long magic)
563 /* We have to fork here, since the kernel calls do_exit(0) in
564 * linux/kernel/sys.c, which can cause the machine to panic when
565 * the init process is killed.... */
567 if (pid == 0) { /* child */
571 waitpid(pid, NULL, 0);
574 static void shutdown_system(void)
576 sigset_t block_signals;
578 /* run everything to be run at "shutdown". This is done _prior_
579 * to killing everything, in case people wish to use scripts to
580 * shut things down gracefully... */
581 run_actions(SHUTDOWN);
583 /* first disable all our signals */
584 sigemptyset(&block_signals);
585 sigaddset(&block_signals, SIGHUP);
586 sigaddset(&block_signals, SIGQUIT);
587 sigaddset(&block_signals, SIGCHLD);
588 sigaddset(&block_signals, SIGUSR1);
589 sigaddset(&block_signals, SIGUSR2);
590 sigaddset(&block_signals, SIGINT);
591 sigaddset(&block_signals, SIGTERM);
592 sigaddset(&block_signals, SIGCONT);
593 sigaddset(&block_signals, SIGSTOP);
594 sigaddset(&block_signals, SIGTSTP);
595 sigprocmask(SIG_BLOCK, &block_signals, NULL);
597 message(L_CONSOLE | L_LOG, "The system is going down NOW!");
599 /* Allow Ctrl-Alt-Del to reboot system. */
600 init_reboot(RB_ENABLE_CAD);
602 /* Send signals to every process _except_ pid 1 */
603 message(L_CONSOLE | L_LOG, "Sending SIG%s to all processes", "TERM");
608 message(L_CONSOLE | L_LOG, "Sending SIG%s to all processes", "KILL");
614 static void exec_signal(int sig ATTRIBUTE_UNUSED)
616 struct init_action *a, *tmp;
617 sigset_t unblock_signals;
619 for (a = init_action_list; a; a = tmp) {
621 if (a->action & RESTART) {
624 /* unblock all signals, blocked in shutdown_system() */
625 sigemptyset(&unblock_signals);
626 sigaddset(&unblock_signals, SIGHUP);
627 sigaddset(&unblock_signals, SIGQUIT);
628 sigaddset(&unblock_signals, SIGCHLD);
629 sigaddset(&unblock_signals, SIGUSR1);
630 sigaddset(&unblock_signals, SIGUSR2);
631 sigaddset(&unblock_signals, SIGINT);
632 sigaddset(&unblock_signals, SIGTERM);
633 sigaddset(&unblock_signals, SIGCONT);
634 sigaddset(&unblock_signals, SIGSTOP);
635 sigaddset(&unblock_signals, SIGTSTP);
636 sigprocmask(SIG_UNBLOCK, &unblock_signals, NULL);
638 /* Open the new terminal device */
639 open_stdio_to_tty(a->terminal, 0);
641 messageD(L_CONSOLE | L_LOG, "Trying to re-exec %s", a->command);
642 BB_EXECLP(a->command, a->command, NULL);
644 message(L_CONSOLE | L_LOG, "Cannot run '%s': %s",
645 a->command, strerror(errno));
647 init_reboot(RB_HALT_SYSTEM);
653 static void shutdown_signal(int sig)
662 if (sig == SIGTERM) {
665 } else if (sig == SIGUSR2) {
669 message(L_CONSOLE | L_LOG, "Requesting system %s", m);
670 /* allow time for last message to reach serial console */
676 static void ctrlaltdel_signal(int sig ATTRIBUTE_UNUSED)
678 run_actions(CTRLALTDEL);
681 /* The SIGSTOP & SIGTSTP handler */
682 static void stop_handler(int sig ATTRIBUTE_UNUSED)
684 int saved_errno = errno;
693 /* The SIGCONT handler */
694 static void cont_handler(int sig ATTRIBUTE_UNUSED)
699 #endif /* !ENABLE_DEBUG_INIT */
701 static void new_init_action(int action, const char *command, const char *cons)
703 struct init_action *new_action, *a, *last;
705 if (strcmp(cons, bb_dev_null) == 0 && (action & ASKFIRST))
708 /* Append to the end of the list */
709 for (a = last = init_action_list; a; a = a->next) {
710 /* don't enter action if it's already in the list,
711 * but do overwrite existing actions */
712 if ((strcmp(a->command, command) == 0)
713 && (strcmp(a->terminal, cons) == 0)
721 new_action = xzalloc(sizeof(struct init_action));
723 last->next = new_action;
725 init_action_list = new_action;
727 strcpy(new_action->command, command);
728 new_action->action = action;
729 strcpy(new_action->terminal, cons);
730 messageD(L_LOG | L_CONSOLE, "command='%s' action=%d tty='%s'\n",
731 new_action->command, new_action->action, new_action->terminal);
734 static void delete_init_action(struct init_action *action)
736 struct init_action *a, *b = NULL;
738 for (a = init_action_list; a; b = a, a = a->next) {
741 init_action_list = a->next;
751 /* NOTE that if CONFIG_FEATURE_USE_INITTAB is NOT defined,
752 * then parse_inittab() simply adds in some default
753 * actions(i.e., runs INIT_SCRIPT and then starts a pair
754 * of "askfirst" shells). If CONFIG_FEATURE_USE_INITTAB
755 * _is_ defined, but /etc/inittab is missing, this
756 * results in the same set of default behaviors.
758 static void parse_inittab(void)
760 #if ENABLE_FEATURE_USE_INITTAB
762 char buf[INIT_BUFFS_SIZE], lineAsRead[INIT_BUFFS_SIZE];
763 char tmpConsole[CONSOLE_NAME_SIZE];
764 char *id, *runlev, *action, *command, *eol;
765 const struct init_action_type *a = actions;
767 file = fopen(INITTAB, "r");
769 /* No inittab file -- set up some default behavior */
771 /* Reboot on Ctrl-Alt-Del */
772 new_init_action(CTRLALTDEL, "reboot", "");
773 /* Umount all filesystems on halt/reboot */
774 new_init_action(SHUTDOWN, "umount -a -r", "");
775 /* Swapoff on halt/reboot */
776 if (ENABLE_SWAPONOFF) new_init_action(SHUTDOWN, "swapoff -a", "");
777 /* Prepare to restart init when a HUP is received */
778 new_init_action(RESTART, "init", "");
779 /* Askfirst shell on tty1-4 */
780 new_init_action(ASKFIRST, bb_default_login_shell, "");
781 new_init_action(ASKFIRST, bb_default_login_shell, VC_2);
782 new_init_action(ASKFIRST, bb_default_login_shell, VC_3);
783 new_init_action(ASKFIRST, bb_default_login_shell, VC_4);
785 new_init_action(SYSINIT, INIT_SCRIPT, "");
788 #if ENABLE_FEATURE_USE_INITTAB
791 while (fgets(buf, INIT_BUFFS_SIZE, file) != NULL) {
792 /* Skip leading spaces */
793 for (id = buf; *id == ' ' || *id == '\t'; id++);
795 /* Skip the line if it's a comment */
796 if (*id == '#' || *id == '\n')
799 /* Trim the trailing \n */
801 eol = strrchr(id, '\n');
805 /* Keep a copy around for posterity's sake (and error msgs) */
806 strcpy(lineAsRead, buf);
808 /* Separate the ID field from the runlevels */
809 runlev = strchr(id, ':');
810 if (runlev == NULL || *(runlev + 1) == '\0') {
811 message(L_LOG | L_CONSOLE, "Bad inittab entry: %s", lineAsRead);
818 /* Separate the runlevels from the action */
819 action = strchr(runlev, ':');
820 if (action == NULL || *(action + 1) == '\0') {
821 message(L_LOG | L_CONSOLE, "Bad inittab entry: %s", lineAsRead);
828 /* Separate the action from the command */
829 command = strchr(action, ':');
830 if (command == NULL || *(command + 1) == '\0') {
831 message(L_LOG | L_CONSOLE, "Bad inittab entry: %s", lineAsRead);
838 /* Ok, now process it */
839 for (a = actions; a->name != 0; a++) {
840 if (strcmp(a->name, action) == 0) {
842 if (strncmp(id, "/dev/", 5) == 0)
844 strcpy(tmpConsole, "/dev/");
845 safe_strncpy(tmpConsole + 5, id,
846 sizeof(tmpConsole) - 5);
849 new_init_action(a->action, command, id);
854 /* Choke on an unknown action */
855 message(L_LOG | L_CONSOLE, "Bad inittab entry: %s", lineAsRead);
859 #endif /* FEATURE_USE_INITTAB */
862 #if ENABLE_FEATURE_USE_INITTAB
863 static void reload_signal(int sig ATTRIBUTE_UNUSED)
865 struct init_action *a, *tmp;
867 message(L_LOG, "reloading /etc/inittab");
869 /* disable old entrys */
870 for (a = init_action_list; a; a = a->next ) {
876 /* remove unused entrys */
877 for (a = init_action_list; a; a = tmp) {
879 if ((a->action & (ONCE | SYSINIT | WAIT)) && a->pid == 0) {
880 delete_init_action(a);
883 run_actions(RESPAWN);
885 #endif /* FEATURE_USE_INITTAB */
887 int init_main(int argc, char **argv);
888 int init_main(int argc, char **argv)
890 struct init_action *a;
893 die_sleep = 30 * 24*60*60; /* if xmalloc will ever die... */
895 if (argc > 1 && !strcmp(argv[1], "-q")) {
896 return kill(1, SIGHUP);
898 #if !ENABLE_DEBUG_INIT
899 /* Expect to be invoked as init with PID=1 or be invoked as linuxrc */
901 && (!ENABLE_FEATURE_INITRD || !strstr(applet_name, "linuxrc"))
905 /* Set up sig handlers -- be sure to
906 * clear all of these in run() */
907 signal(SIGHUP, exec_signal);
908 signal(SIGQUIT, exec_signal);
909 signal(SIGUSR1, shutdown_signal);
910 signal(SIGUSR2, shutdown_signal);
911 signal(SIGINT, ctrlaltdel_signal);
912 signal(SIGTERM, shutdown_signal);
913 signal(SIGCONT, cont_handler);
914 signal(SIGSTOP, stop_handler);
915 signal(SIGTSTP, stop_handler);
917 /* Turn off rebooting via CTL-ALT-DEL -- we get a
918 * SIGINT on CAD so we can shut things down gracefully... */
919 init_reboot(RB_DISABLE_CAD);
922 /* Figure out where the default console should be */
928 const char * const *e;
929 /* Make sure environs is set to something sane */
930 for (e = environment; *e; e++)
934 if (argc > 1) setenv("RUNLEVEL", argv[1], 1);
937 message(MAYBE_CONSOLE | L_LOG, "init started: %s", bb_banner);
939 /* Make sure there is enough memory to do something useful. */
940 if (ENABLE_SWAPONOFF) {
943 if (!sysinfo(&info) &&
944 (info.mem_unit ? : 1) * (long long)info.totalram < 1024*1024)
946 message(L_CONSOLE, "Low memory, forcing swapon");
947 /* swapon -a requires /proc typically */
948 new_init_action(SYSINIT, "mount -t proc proc /proc", "");
949 /* Try to turn on swap */
950 new_init_action(SYSINIT, "swapon -a", "");
951 run_actions(SYSINIT); /* wait and removing */
955 /* Check if we are supposed to be in single user mode */
957 && (!strcmp(argv[1], "single") || !strcmp(argv[1], "-s") || LONE_CHAR(argv[1], '1'))
959 /* Start a shell on console */
960 new_init_action(RESPAWN, bb_default_login_shell, "");
962 /* Not in single user mode -- see what inittab says */
964 /* NOTE that if CONFIG_FEATURE_USE_INITTAB is NOT defined,
965 * then parse_inittab() simply adds in some default
966 * actions(i.e., runs INIT_SCRIPT and then starts a pair
967 * of "askfirst" shells */
972 if (getenv("SELINUX_INIT") == NULL) {
975 putenv("SELINUX_INIT=YES");
976 if (selinux_init_load_policy(&enforce) == 0) {
977 BB_EXECVP(argv[0], argv);
978 } else if (enforce > 0) {
979 /* SELinux in enforcing mode but load_policy failed */
980 /* At this point, we probably can't open /dev/console, so log() won't work */
981 message(L_CONSOLE, "Cannot load SELinux Policy. "
982 "Machine is in enforcing mode. Halting now.");
986 #endif /* CONFIG_SELINUX */
988 /* Make the command line just say "init" -- thats all, nothing else */
989 fixup_argv(argc, argv, "init");
991 /* Now run everything that needs to be run */
993 /* First run the sysinit command */
994 run_actions(SYSINIT);
996 /* Next run anything that wants to block */
999 /* Next run anything to be run only once */
1002 #if ENABLE_FEATURE_USE_INITTAB
1003 /* Redefine SIGHUP to reread /etc/inittab */
1004 signal(SIGHUP, reload_signal);
1006 signal(SIGHUP, SIG_IGN);
1007 #endif /* FEATURE_USE_INITTAB */
1009 /* Now run the looping stuff for the rest of forever */
1011 /* run the respawn stuff */
1012 run_actions(RESPAWN);
1014 /* run the askfirst stuff */
1015 run_actions(ASKFIRST);
1017 /* Don't consume all CPU time -- sleep a bit */
1020 /* Wait for a child process to exit */
1023 /* Find out who died and clean up their corpse */
1024 for (a = init_action_list; a; a = a->next) {
1025 if (a->pid == wpid) {
1026 /* Set the pid to 0 so that the process gets
1027 * restarted by run_actions() */
1029 message(L_LOG, "process '%s' (pid %d) exited. "
1030 "Scheduling it for restart.",
1034 /* see if anyone else is waiting to be reaped */
1035 wpid = waitpid(-1, NULL, WNOHANG);