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>
16 #if ENABLE_FEATURE_INIT_SYSLOG
17 # include <sys/syslog.h>
20 #define INIT_BUFFS_SIZE 256
21 #define CONSOLE_NAME_SIZE 32
22 #define MAXENV 16 /* Number of env. vars */
24 #if ENABLE_FEATURE_INIT_COREDUMPS
26 * When a file named CORE_ENABLE_FLAG_FILE exists, setrlimit is called
27 * before processes are spawned to set core file size as unlimited.
28 * This is for debugging only. Don't use this is production, unless
29 * you want core dumps lying about....
31 #define CORE_ENABLE_FLAG_FILE "/.init_enable_core"
32 #include <sys/resource.h>
35 #define INITTAB "/etc/inittab" /* inittab file location */
37 #define INIT_SCRIPT "/etc/init.d/rcS" /* Default sysinit script. */
40 /* Allowed init action types */
43 #define ASKFIRST 0x004
46 #define CTRLALTDEL 0x020
47 #define SHUTDOWN 0x040
50 #define STR_SYSINIT "\x01"
51 #define STR_RESPAWN "\x02"
52 #define STR_ASKFIRST "\x04"
53 #define STR_WAIT "\x08"
54 #define STR_ONCE "\x10"
55 #define STR_CTRLALTDEL "\x20"
56 #define STR_SHUTDOWN "\x40"
57 #define STR_RESTART "\x80"
59 /* Set up a linked list of init_actions, to be read from inittab */
61 struct init_action *next;
64 char terminal[CONSOLE_NAME_SIZE];
65 char command[INIT_BUFFS_SIZE];
68 /* Static variables */
69 static struct init_action *init_action_list = NULL;
71 #if !ENABLE_FEATURE_INIT_SYSLOG
72 static const char *log_console = VC_5;
74 #if !ENABLE_DEBUG_INIT
75 static sig_atomic_t got_cont = 0;
82 #if ENABLE_FEATURE_EXTRA_QUIET
85 MAYBE_CONSOLE = L_CONSOLE,
88 #ifndef RB_HALT_SYSTEM
89 RB_HALT_SYSTEM = 0xcdef0123, /* FIXME: this overflows enum */
90 RB_ENABLE_CAD = 0x89abcdef,
92 RB_POWER_OFF = 0x4321fedc,
93 RB_AUTOBOOT = 0x01234567,
97 static const char *const environment[] = {
105 /* Function prototypes */
106 static void delete_init_action(struct init_action *a);
107 static int waitfor(pid_t pid);
108 #if !ENABLE_DEBUG_INIT
109 static void shutdown_signal(int sig);
112 #if !ENABLE_DEBUG_INIT
113 static void loop_forever(void)
120 /* Print a message to the specified device.
121 * Device may be bitwise-or'd from L_LOG | L_CONSOLE */
122 #if ENABLE_DEBUG_INIT
123 #define messageD message
125 #define messageD(...) do {} while (0)
127 static void message(int device, const char *fmt, ...)
128 __attribute__ ((format(printf, 2, 3)));
129 static void message(int device, const char *fmt, ...)
131 #if !ENABLE_FEATURE_INIT_SYSLOG
132 static int log_fd = -1;
140 va_start(arguments, fmt);
141 vsnprintf(msg + 1, sizeof(msg) - 2, fmt, arguments);
143 msg[sizeof(msg) - 2] = '\0';
146 #if ENABLE_FEATURE_INIT_SYSLOG
147 /* Log the message to syslogd */
148 if (device & L_LOG) {
150 openlog(applet_name, 0, LOG_DAEMON);
151 syslog(LOG_INFO, "init: %s", msg + 1);
159 /* Take full control of the log tty, and never close it.
160 * It's mine, all mine! Muhahahaha! */
165 log_fd = device_open(log_console, O_WRONLY | O_NONBLOCK | O_NOCTTY);
167 bb_error_msg("can't log to %s", log_console);
170 close_on_exec_on(log_fd);
174 if (device & L_LOG) {
175 full_write(log_fd, msg, l);
177 return; /* don't print dup messages */
181 if (device & L_CONSOLE) {
182 /* Send console messages to console so people will see them. */
183 full_write(2, msg, l);
187 /* From <linux/serial.h> */
188 struct serial_struct {
197 unsigned short close_delay;
199 char reserved_char[1];
201 unsigned short closing_wait; /* time to wait before closing */
202 unsigned short closing_wait2; /* no longer used... */
203 unsigned char *iomem_base;
204 unsigned short iomem_reg_shift;
205 unsigned int port_high;
206 unsigned long iomap_base; /* cookie passed into ioremap */
208 /* Paranoia (imagine 64bit kernel overwriting 32bit userspace stack) */
209 uint32_t bbox_reserved[16];
211 static void console_init(void)
213 struct serial_struct sr;
216 s = getenv("CONSOLE");
217 if (!s) s = getenv("console");
219 int fd = open(s, O_RDWR | O_NONBLOCK | O_NOCTTY);
224 while (fd > 2) close(fd--);
226 messageD(L_LOG, "console='%s'", s);
228 /* Make sure fd 0,1,2 are not closed */
233 if (ioctl(0, TIOCGSERIAL, &sr) == 0) {
234 /* Force the TERM setting to vt102 for serial console
235 * if TERM is set to linux (the default) */
236 if (!s || strcmp(s, "linux") == 0)
237 putenv((char*)"TERM=vt102");
238 #if !ENABLE_FEATURE_INIT_SYSLOG
242 putenv((char*)"TERM=linux");
245 /* Set terminal settings to reasonable defaults */
246 static void set_sane_term(void)
250 tcgetattr(STDIN_FILENO, &tty);
252 /* set control chars */
253 tty.c_cc[VINTR] = 3; /* C-c */
254 tty.c_cc[VQUIT] = 28; /* C-\ */
255 tty.c_cc[VERASE] = 127; /* C-? */
256 tty.c_cc[VKILL] = 21; /* C-u */
257 tty.c_cc[VEOF] = 4; /* C-d */
258 tty.c_cc[VSTART] = 17; /* C-q */
259 tty.c_cc[VSTOP] = 19; /* C-s */
260 tty.c_cc[VSUSP] = 26; /* C-z */
262 /* use line dicipline 0 */
265 /* Make it be sane */
266 tty.c_cflag &= CBAUD | CBAUDEX | CSIZE | CSTOPB | PARENB | PARODD;
267 tty.c_cflag |= CREAD | HUPCL | CLOCAL;
270 tty.c_iflag = ICRNL | IXON | IXOFF;
273 tty.c_oflag = OPOST | ONLCR;
277 ISIG | ICANON | ECHO | ECHOE | ECHOK | ECHOCTL | ECHOKE | IEXTEN;
279 tcsetattr(STDIN_FILENO, TCSANOW, &tty);
282 /* Open the new terminal device */
283 static void open_stdio_to_tty(const char* tty_name, int fail)
285 /* empty tty_name means "use init's tty", else... */
287 int fd = device_open(tty_name, O_RDWR);
289 message(L_LOG | L_CONSOLE, "Can't open %s: %s",
290 tty_name, strerror(errno));
293 #if !ENABLE_DEBUG_INIT
294 shutdown_signal(SIGUSR1);
302 if (fd > 2) close(fd);
308 /* Used only by run_actions */
309 static pid_t run(const struct init_action *a)
313 char *s, *tmpCmd, *cmdpath;
314 char *cmd[INIT_BUFFS_SIZE];
315 char buf[INIT_BUFFS_SIZE + 6]; /* INIT_BUFFS_SIZE+strlen("exec ")+1 */
316 sigset_t nmask, omask;
318 /* Block sigchild while forking (why?) */
320 sigaddset(&nmask, SIGCHLD);
321 sigprocmask(SIG_BLOCK, &nmask, &omask);
323 sigprocmask(SIG_SETMASK, &omask, NULL);
326 message(L_LOG | L_CONSOLE, "Can't fork");
332 /* Reset signal handlers that were set by the parent process */
333 signal(SIGUSR1, SIG_DFL);
334 signal(SIGUSR2, SIG_DFL);
335 signal(SIGINT, SIG_DFL);
336 signal(SIGTERM, SIG_DFL);
337 signal(SIGHUP, SIG_DFL);
338 signal(SIGQUIT, SIG_DFL);
339 signal(SIGCONT, SIG_DFL);
340 signal(SIGSTOP, SIG_DFL);
341 signal(SIGTSTP, SIG_DFL);
343 /* Create a new session and make ourself the process
347 /* Open the new terminal device */
348 open_stdio_to_tty(a->terminal, 1 /* - exit if open fails*/);
350 #ifdef BUT_RUN_ACTIONS_ALREADY_DOES_WAITING
351 /* If the init Action requires us to wait, then force the
352 * supplied terminal to be the controlling tty. */
353 if (a->action & (SYSINIT | WAIT | CTRLALTDEL | SHUTDOWN | RESTART)) {
355 /* Now fork off another process to just hang around */
358 message(L_LOG | L_CONSOLE, "Can't fork");
363 /* Parent - wait till the child is done */
364 signal(SIGINT, SIG_IGN);
365 signal(SIGTSTP, SIG_IGN);
366 signal(SIGQUIT, SIG_IGN);
367 signal(SIGCHLD, SIG_DFL);
370 /* See if stealing the controlling tty back is necessary */
371 if (tcgetpgrp(0) != getpid())
374 /* Use a temporary process to steal the controlling tty. */
377 message(L_LOG | L_CONSOLE, "Can't fork");
382 ioctl(0, TIOCSCTTY, 1);
389 /* Child - fall though to actually execute things */
393 /* See if any special /bin/sh requiring characters are present */
394 if (strpbrk(a->command, "~`!$^&*()=|\\{}[];\"'<>?") != NULL) {
395 cmd[0] = (char*)DEFAULT_SHELL;
396 cmd[1] = (char*)"-c";
397 cmd[2] = strcat(strcpy(buf, "exec "), a->command);
400 /* Convert command (char*) into cmd (char**, one word per string) */
401 strcpy(buf, a->command);
403 for (tmpCmd = buf, i = 0; (tmpCmd = strsep(&s, " \t")) != NULL;) {
404 if (*tmpCmd != '\0') {
415 * Interactive shells want to see a dash in argv[0]. This
416 * typically is handled by login, argv will be setup this
417 * way if a dash appears at the front of the command path
420 if (*cmdpath == '-') {
421 /* skip over the dash */
424 #ifdef WHY_WE_DO_THIS_SHELL_MUST_HANDLE_THIS_ITSELF
425 /* find the last component in the command pathname */
426 s = bb_get_last_path_component_nostrip(cmdpath);
427 /* make a new argv[0] */
428 cmd[0] = malloc(strlen(s) + 2);
429 if (cmd[0] == NULL) {
430 message(L_LOG | L_CONSOLE, bb_msg_memory_exhausted);
434 strcpy(cmd[0] + 1, s);
438 #if ENABLE_FEATURE_INIT_SCTTY
439 /* Establish this process as session leader and
440 * _attempt_ to make stdin a controlling tty.
442 ioctl(0, TIOCSCTTY, 0 /*only try, don't steal*/);
446 if (a->action & ASKFIRST) {
447 static const char press_enter[] ALIGN1 =
448 #ifdef CUSTOMIZED_BANNER
449 #include CUSTOMIZED_BANNER
451 "\nPlease press Enter to activate this console. ";
454 * Save memory by not exec-ing anything large (like a shell)
455 * before the user wants it. This is critical if swap is not
456 * enabled and the system has low memory. Generally this will
457 * be run on the second virtual console, and the first will
458 * be allowed to start a shell or whatever an init script
461 messageD(L_LOG, "waiting for enter to start '%s'"
462 "(pid %d, tty '%s')\n",
463 cmdpath, getpid(), a->terminal);
464 full_write(1, press_enter, sizeof(press_enter) - 1);
465 while (safe_read(0, &c, 1) == 1 && c != '\n')
469 /* Log the process name and args */
470 message(L_LOG, "starting pid %d, tty '%s': '%s'",
471 getpid(), a->terminal, cmdpath);
473 #if ENABLE_FEATURE_INIT_COREDUMPS
476 if (stat(CORE_ENABLE_FLAG_FILE, &sb) == 0) {
479 limit.rlim_cur = RLIM_INFINITY;
480 limit.rlim_max = RLIM_INFINITY;
481 setrlimit(RLIMIT_CORE, &limit);
485 /* Now run it. The new program will take over this PID,
486 * so nothing further in init.c should be run. */
487 BB_EXECVP(cmdpath, cmd);
489 /* We're still here? Some error happened. */
490 message(L_LOG | L_CONSOLE, "Cannot run '%s': %s",
491 cmdpath, strerror(errno));
495 static int waitfor(pid_t runpid)
500 wpid = waitpid(runpid, &status, 0);
501 if (wpid == -1 && errno == EINTR)
508 /* Run all commands of a particular type */
509 static void run_actions(int action)
511 struct init_action *a, *tmp;
513 for (a = init_action_list; a; a = tmp) {
515 if (a->action == action) {
516 /* a->terminal of "" means "init's console" */
517 if (a->terminal[0] && access(a->terminal, R_OK | W_OK)) {
518 //message(L_LOG | L_CONSOLE, "Device %s cannot be opened in RW mode", a->terminal /*, strerror(errno)*/);
519 delete_init_action(a);
520 } else if (a->action & (SYSINIT | WAIT | CTRLALTDEL | SHUTDOWN | RESTART)) {
522 delete_init_action(a);
523 } else if (a->action & ONCE) {
525 delete_init_action(a);
526 } else if (a->action & (RESPAWN | ASKFIRST)) {
527 /* Only run stuff with pid==0. If they have
528 * a pid, that means it is still running */
537 #if !ENABLE_DEBUG_INIT
538 static void init_reboot(unsigned long magic)
541 /* We have to fork here, since the kernel calls do_exit(0) in
542 * linux/kernel/sys.c, which can cause the machine to panic when
543 * the init process is killed.... */
545 if (pid == 0) { /* child */
549 waitpid(pid, NULL, 0);
552 static void shutdown_system(void)
554 sigset_t block_signals;
556 /* run everything to be run at "shutdown". This is done _prior_
557 * to killing everything, in case people wish to use scripts to
558 * shut things down gracefully... */
559 run_actions(SHUTDOWN);
561 /* first disable all our signals */
562 sigemptyset(&block_signals);
563 sigaddset(&block_signals, SIGHUP);
564 sigaddset(&block_signals, SIGQUIT);
565 sigaddset(&block_signals, SIGCHLD);
566 sigaddset(&block_signals, SIGUSR1);
567 sigaddset(&block_signals, SIGUSR2);
568 sigaddset(&block_signals, SIGINT);
569 sigaddset(&block_signals, SIGTERM);
570 sigaddset(&block_signals, SIGCONT);
571 sigaddset(&block_signals, SIGSTOP);
572 sigaddset(&block_signals, SIGTSTP);
573 sigprocmask(SIG_BLOCK, &block_signals, NULL);
575 message(L_CONSOLE | L_LOG, "The system is going down NOW!");
577 /* Allow Ctrl-Alt-Del to reboot system. */
578 init_reboot(RB_ENABLE_CAD);
580 /* Send signals to every process _except_ pid 1 */
581 message(L_CONSOLE | L_LOG, "Sending SIG%s to all processes", "TERM");
586 message(L_CONSOLE | L_LOG, "Sending SIG%s to all processes", "KILL");
592 static void shutdown_signal(int sig)
601 if (sig == SIGTERM) {
604 } else if (sig == SIGUSR2) {
608 message(L_CONSOLE | L_LOG, "Requesting system %s", m);
609 /* allow time for last message to reach serial console */
615 static void exec_signal(int sig ATTRIBUTE_UNUSED)
617 struct init_action *a, *tmp;
618 sigset_t unblock_signals;
620 for (a = init_action_list; a; a = tmp) {
622 if (a->action & RESTART) {
625 /* unblock all signals, blocked in shutdown_system() */
626 sigemptyset(&unblock_signals);
627 sigaddset(&unblock_signals, SIGHUP);
628 sigaddset(&unblock_signals, SIGQUIT);
629 sigaddset(&unblock_signals, SIGCHLD);
630 sigaddset(&unblock_signals, SIGUSR1);
631 sigaddset(&unblock_signals, SIGUSR2);
632 sigaddset(&unblock_signals, SIGINT);
633 sigaddset(&unblock_signals, SIGTERM);
634 sigaddset(&unblock_signals, SIGCONT);
635 sigaddset(&unblock_signals, SIGSTOP);
636 sigaddset(&unblock_signals, SIGTSTP);
637 sigprocmask(SIG_UNBLOCK, &unblock_signals, NULL);
639 /* Open the new terminal device */
640 open_stdio_to_tty(a->terminal, 0 /* - shutdown_signal(SIGUSR1) [halt] if open fails */);
642 messageD(L_CONSOLE | L_LOG, "Trying to re-exec %s", a->command);
643 BB_EXECLP(a->command, a->command, NULL);
645 message(L_CONSOLE | L_LOG, "Cannot run '%s': %s",
646 a->command, strerror(errno));
648 init_reboot(RB_HALT_SYSTEM);
654 static void ctrlaltdel_signal(int sig ATTRIBUTE_UNUSED)
656 run_actions(CTRLALTDEL);
659 /* The SIGSTOP & SIGTSTP handler */
660 static void stop_handler(int sig ATTRIBUTE_UNUSED)
662 int saved_errno = errno;
671 /* The SIGCONT handler */
672 static void cont_handler(int sig ATTRIBUTE_UNUSED)
677 #endif /* !ENABLE_DEBUG_INIT */
679 static void new_init_action(uint8_t action, const char *command, const char *cons)
681 struct init_action *new_action, *a, *last;
683 if (strcmp(cons, bb_dev_null) == 0 && (action & ASKFIRST))
686 /* Append to the end of the list */
687 for (a = last = init_action_list; a; a = a->next) {
688 /* don't enter action if it's already in the list,
689 * but do overwrite existing actions */
690 if ((strcmp(a->command, command) == 0)
691 && (strcmp(a->terminal, cons) == 0)
699 new_action = xzalloc(sizeof(struct init_action));
701 last->next = new_action;
703 init_action_list = new_action;
705 strcpy(new_action->command, command);
706 new_action->action = action;
707 strcpy(new_action->terminal, cons);
708 messageD(L_LOG | L_CONSOLE, "command='%s' action=%d tty='%s'\n",
709 new_action->command, new_action->action, new_action->terminal);
712 static void delete_init_action(struct init_action *action)
714 struct init_action *a, *b = NULL;
716 for (a = init_action_list; a; b = a, a = a->next) {
719 init_action_list = a->next;
729 /* NOTE that if CONFIG_FEATURE_USE_INITTAB is NOT defined,
730 * then parse_inittab() simply adds in some default
731 * actions(i.e., runs INIT_SCRIPT and then starts a pair
732 * of "askfirst" shells). If CONFIG_FEATURE_USE_INITTAB
733 * _is_ defined, but /etc/inittab is missing, this
734 * results in the same set of default behaviors.
736 static void parse_inittab(void)
738 #if ENABLE_FEATURE_USE_INITTAB
739 static const char actions[] =
740 STR_SYSINIT "sysinit\0"
741 STR_RESPAWN "respawn\0"
742 STR_ASKFIRST "askfirst\0"
745 STR_CTRLALTDEL "ctrlaltdel\0"
746 STR_SHUTDOWN "shutdown\0"
747 STR_RESTART "restart\0"
751 char buf[INIT_BUFFS_SIZE], lineAsRead[INIT_BUFFS_SIZE];
752 char tmpConsole[CONSOLE_NAME_SIZE];
753 char *id, *runlev, *action, *command, *eol;
755 file = fopen(INITTAB, "r");
757 /* No inittab file -- set up some default behavior */
759 /* Reboot on Ctrl-Alt-Del */
760 new_init_action(CTRLALTDEL, "reboot", "");
761 /* Umount all filesystems on halt/reboot */
762 new_init_action(SHUTDOWN, "umount -a -r", "");
763 /* Swapoff on halt/reboot */
764 if (ENABLE_SWAPONOFF)
765 new_init_action(SHUTDOWN, "swapoff -a", "");
766 /* Prepare to restart init when a HUP is received */
767 new_init_action(RESTART, "init", "");
768 /* Askfirst shell on tty1-4 */
769 new_init_action(ASKFIRST, bb_default_login_shell, "");
770 new_init_action(ASKFIRST, bb_default_login_shell, VC_2);
771 new_init_action(ASKFIRST, bb_default_login_shell, VC_3);
772 new_init_action(ASKFIRST, bb_default_login_shell, VC_4);
774 new_init_action(SYSINIT, INIT_SCRIPT, "");
777 #if ENABLE_FEATURE_USE_INITTAB
780 while (fgets(buf, INIT_BUFFS_SIZE, file) != NULL) {
783 /* Skip leading spaces */
784 for (id = buf; *id == ' ' || *id == '\t'; id++);
786 /* Skip the line if it's a comment */
787 if (*id == '#' || *id == '\n')
790 /* Trim the trailing \n */
792 eol = strrchr(id, '\n');
796 /* Keep a copy around for posterity's sake (and error msgs) */
797 strcpy(lineAsRead, buf);
799 /* Separate the ID field from the runlevels */
800 runlev = strchr(id, ':');
801 if (runlev == NULL || *(runlev + 1) == '\0') {
802 message(L_LOG | L_CONSOLE, "Bad inittab entry: %s", lineAsRead);
809 /* Separate the runlevels from the action */
810 action = strchr(runlev, ':');
811 if (action == NULL || *(action + 1) == '\0') {
812 message(L_LOG | L_CONSOLE, "Bad inittab entry: %s", lineAsRead);
819 /* Separate the action from the command */
820 command = strchr(action, ':');
821 if (command == NULL || *(command + 1) == '\0') {
822 message(L_LOG | L_CONSOLE, "Bad inittab entry: %s", lineAsRead);
829 /* Ok, now process it */
830 for (a = actions; a[0]; a += strlen(a) + 1) {
831 if (strcmp(a + 1, action) == 0) {
833 if (strncmp(id, "/dev/", 5) == 0)
835 strcpy(tmpConsole, "/dev/");
836 safe_strncpy(tmpConsole + 5, id,
837 sizeof(tmpConsole) - 5);
840 new_init_action((uint8_t)a[0], command, id);
845 /* Choke on an unknown action */
846 message(L_LOG | L_CONSOLE, "Bad inittab entry: %s", lineAsRead);
850 #endif /* FEATURE_USE_INITTAB */
853 #if ENABLE_FEATURE_USE_INITTAB
854 static void reload_signal(int sig ATTRIBUTE_UNUSED)
856 struct init_action *a, *tmp;
858 message(L_LOG, "reloading /etc/inittab");
860 /* disable old entrys */
861 for (a = init_action_list; a; a = a->next ) {
867 /* remove unused entrys */
868 for (a = init_action_list; a; a = tmp) {
870 if ((a->action & (ONCE | SYSINIT | WAIT)) && a->pid == 0) {
871 delete_init_action(a);
874 run_actions(RESPAWN);
876 #endif /* FEATURE_USE_INITTAB */
878 int init_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
879 int init_main(int argc, char **argv)
881 struct init_action *a;
884 die_sleep = 30 * 24*60*60; /* if xmalloc will ever die... */
886 if (argc > 1 && !strcmp(argv[1], "-q")) {
887 return kill(1, SIGHUP);
889 #if !ENABLE_DEBUG_INIT
890 /* Expect to be invoked as init with PID=1 or be invoked as linuxrc */
892 && (!ENABLE_FEATURE_INITRD || !strstr(applet_name, "linuxrc"))
896 /* Set up sig handlers -- be sure to
897 * clear all of these in run() */
898 signal(SIGHUP, exec_signal);
899 signal(SIGQUIT, exec_signal);
900 signal(SIGUSR1, shutdown_signal);
901 signal(SIGUSR2, shutdown_signal);
902 signal(SIGINT, ctrlaltdel_signal);
903 signal(SIGTERM, shutdown_signal);
904 signal(SIGCONT, cont_handler);
905 signal(SIGSTOP, stop_handler);
906 signal(SIGTSTP, stop_handler);
908 /* Turn off rebooting via CTL-ALT-DEL -- we get a
909 * SIGINT on CAD so we can shut things down gracefully... */
910 init_reboot(RB_DISABLE_CAD);
914 /* Figure out where the default console should be */
920 const char *const *e;
921 /* Make sure environs is set to something sane */
922 for (e = environment; *e; e++)
926 if (argc > 1) setenv("RUNLEVEL", argv[1], 1);
929 message(MAYBE_CONSOLE | L_LOG, "init started: %s", bb_banner);
931 /* Make sure there is enough memory to do something useful. */
932 if (ENABLE_SWAPONOFF) {
935 if (!sysinfo(&info) &&
936 (info.mem_unit ? : 1) * (long long)info.totalram < 1024*1024)
938 message(L_CONSOLE, "Low memory, forcing swapon");
939 /* swapon -a requires /proc typically */
940 new_init_action(SYSINIT, "mount -t proc proc /proc", "");
941 /* Try to turn on swap */
942 new_init_action(SYSINIT, "swapon -a", "");
943 run_actions(SYSINIT); /* wait and removing */
947 /* Check if we are supposed to be in single user mode */
949 && (!strcmp(argv[1], "single") || !strcmp(argv[1], "-s") || LONE_CHAR(argv[1], '1'))
951 /* Start a shell on console */
952 new_init_action(RESPAWN, bb_default_login_shell, "");
954 /* Not in single user mode -- see what inittab says */
956 /* NOTE that if CONFIG_FEATURE_USE_INITTAB is NOT defined,
957 * then parse_inittab() simply adds in some default
958 * actions(i.e., runs INIT_SCRIPT and then starts a pair
959 * of "askfirst" shells */
964 if (getenv("SELINUX_INIT") == NULL) {
967 putenv((char*)"SELINUX_INIT=YES");
968 if (selinux_init_load_policy(&enforce) == 0) {
969 BB_EXECVP(argv[0], argv);
970 } else if (enforce > 0) {
971 /* SELinux in enforcing mode but load_policy failed */
972 message(L_CONSOLE, "Cannot load SELinux Policy. "
973 "Machine is in enforcing mode. Halting now.");
977 #endif /* CONFIG_SELINUX */
979 /* Make the command line just say "init" - thats all, nothing else */
980 strncpy(argv[0], "init", strlen(argv[0]));
981 /* Wipe argv[1]-argv[N] so they don't clutter the ps listing */
983 memset(*argv, 0, strlen(*argv));
985 /* Now run everything that needs to be run */
987 /* First run the sysinit command */
988 run_actions(SYSINIT);
990 /* Next run anything that wants to block */
993 /* Next run anything to be run only once */
996 #if ENABLE_FEATURE_USE_INITTAB
997 /* Redefine SIGHUP to reread /etc/inittab */
998 signal(SIGHUP, reload_signal);
1000 signal(SIGHUP, SIG_IGN);
1001 #endif /* FEATURE_USE_INITTAB */
1003 /* Now run the looping stuff for the rest of forever */
1005 /* run the respawn stuff */
1006 run_actions(RESPAWN);
1008 /* run the askfirst stuff */
1009 run_actions(ASKFIRST);
1011 /* Don't consume all CPU time -- sleep a bit */
1014 /* Wait for a child process to exit */
1017 /* Find out who died and clean up their corpse */
1018 for (a = init_action_list; a; a = a->next) {
1019 if (a->pid == wpid) {
1020 /* Set the pid to 0 so that the process gets
1021 * restarted by run_actions() */
1023 message(L_LOG, "process '%s' (pid %d) exited. "
1024 "Scheduling it for restart.",
1028 /* see if anyone else is waiting to be reaped */
1029 wpid = waitpid(-1, NULL, WNOHANG);