1 /* vi: set sw=4 ts=4: */
3 * Mini init implementation for busybox
6 * Copyright (C) 1995, 1996 by Bruce Perens <bruce@pixar.com>.
7 * Adjusted by so many folks, it's impossible to keep track.
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License as published by
11 * the Free Software Foundation; either version 2 of the License, or
12 * (at your option) any later version.
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 * General Public License for more details.
19 * You should have received a copy of the GNU General Public License
20 * along with this program; if not, write to the Free Software
21 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
25 /* Turn this on to disable all the dangerous
26 rebooting stuff when debugging.
31 #include <asm/types.h>
33 #include <linux/serial.h> /* for serial_struct */
34 #include <linux/version.h>
41 #include <sys/fcntl.h>
42 #include <sys/ioctl.h>
43 #include <sys/kdaemon.h>
44 #include <sys/mount.h>
45 #include <sys/reboot.h>
46 #include <sys/sysinfo.h> /* For check_free_memory() */
48 # include <sys/syslog.h>
50 #include <sys/sysmacros.h>
51 #include <sys/types.h>
52 #include <sys/vt.h> /* for vt_stat */
58 #if defined BB_FEATURE_INIT_COREDUMPS
60 * When a file named CORE_ENABLE_FLAG_FILE exists, setrlimit is called
61 * before processes are spawned to set core file size as unlimited.
62 * This is for debugging only. Don't use this is production, unless
63 * you want core dumps lying about....
65 #define CORE_ENABLE_FLAG_FILE "/.init_enable_core"
66 #include <sys/resource.h>
70 #ifndef KERNEL_VERSION
71 #define KERNEL_VERSION(a,b,c) (((a) << 16) + ((b) << 8) + (c))
75 #define VT_PRIMARY "/dev/tty1" /* Primary virtual console */
76 #define VT_SECONDARY "/dev/tty2" /* Virtual console */
77 #define VT_LOG "/dev/tty3" /* Virtual console */
78 #define SERIAL_CON0 "/dev/ttyS0" /* Primary serial console */
79 #define SERIAL_CON1 "/dev/ttyS1" /* Serial console */
80 #define SHELL "/bin/sh" /* Default shell */
81 #define INITTAB "/etc/inittab" /* inittab file location */
83 #define INIT_SCRIPT "/etc/init.d/rcS" /* Default sysinit script. */
89 /* Allowed init action types */
99 /* A mapping between "inittab" action name strings and action type codes. */
100 typedef struct initActionType {
102 initActionEnum action;
105 static const struct initActionType actions[] = {
106 {"sysinit", SYSINIT},
107 {"respawn", RESPAWN},
108 {"askfirst", ASKFIRST},
111 {"ctrlaltdel", CTRLALTDEL},
115 /* Set up a linked list of initActions, to be read from inittab */
116 typedef struct initActionTag initAction;
117 struct initActionTag {
122 initActionEnum action;
124 initAction *initActionList = NULL;
127 static char *secondConsole = VT_SECONDARY;
128 static char *log = VT_LOG;
129 static int kernelVersion = 0;
130 static char termType[32] = "TERM=linux";
131 static char console[32] = _PATH_CONSOLE;
133 static void delete_initAction(initAction * action);
136 /* Print a message to the specified device.
137 * Device may be bitwise-or'd from LOG | CONSOLE */
138 static void message(int device, char *fmt, ...)
139 __attribute__ ((format (printf, 2, 3)));
140 static void message(int device, char *fmt, ...)
147 /* Log the message to syslogd */
151 va_start(arguments, fmt);
152 vsnprintf(msg, sizeof(msg), fmt, arguments);
154 openlog("init", 0, LOG_USER);
155 syslog(LOG_USER|LOG_INFO, msg);
159 static int log_fd = -1;
161 /* Take full control of the log tty, and never close it.
162 * It's mine, all mine! Muhahahaha! */
165 /* don't even try to log, because there is no such console */
167 /* log to main console instead */
169 } else if ((log_fd = device_open(log, O_RDWR|O_NDELAY)) < 0) {
171 fprintf(stderr, "Bummer, can't write to log on %s!\r\n", log);
177 if ((device & LOG) && (log_fd >= 0)) {
178 va_start(arguments, fmt);
179 vdprintf(log_fd, fmt, arguments);
184 if (device & CONSOLE) {
185 /* Always send console messages to /dev/console so people will see them. */
188 device_open(_PATH_CONSOLE,
189 O_WRONLY | O_NOCTTY | O_NDELAY)) >= 0) {
190 va_start(arguments, fmt);
191 vdprintf(fd, fmt, arguments);
195 fprintf(stderr, "Bummer, can't print: ");
196 va_start(arguments, fmt);
197 vfprintf(stderr, fmt, arguments);
205 /* Set terminal settings to reasonable defaults */
206 void set_term(int fd)
212 /* set control chars */
213 tty.c_cc[VINTR] = 3; /* C-c */
214 tty.c_cc[VQUIT] = 28; /* C-\ */
215 tty.c_cc[VERASE] = 127; /* C-? */
216 tty.c_cc[VKILL] = 21; /* C-u */
217 tty.c_cc[VEOF] = 4; /* C-d */
218 tty.c_cc[VSTART] = 17; /* C-q */
219 tty.c_cc[VSTOP] = 19; /* C-s */
220 tty.c_cc[VSUSP] = 26; /* C-z */
222 /* use line dicipline 0 */
225 /* Make it be sane */
226 tty.c_cflag &= CBAUD|CBAUDEX|CSIZE|CSTOPB|PARENB|PARODD;
227 tty.c_cflag |= HUPCL|CLOCAL;
230 tty.c_iflag = ICRNL | IXON | IXOFF;
233 tty.c_oflag = OPOST | ONLCR;
237 ISIG | ICANON | ECHO | ECHOE | ECHOK | ECHOCTL | ECHOKE | IEXTEN;
239 tcsetattr(fd, TCSANOW, &tty);
242 /* How much memory does this machine have? */
243 static int check_free_memory()
248 if (sysinfo(&info) != 0) {
249 message(LOG, "Error checking free memory: %s\n", strerror(errno));
253 return((info.totalram+info.totalswap)/1024);
256 static void console_init()
259 int tried_devcons = 0;
260 int tried_vtprimary = 0;
262 struct serial_struct sr;
265 if ((s = getenv("TERM")) != NULL) {
266 snprintf(termType, sizeof(termType) - 1, "TERM=%s", s);
269 if ((s = getenv("CONSOLE")) != NULL) {
270 snprintf(console, sizeof(console) - 1, "%s", s);
273 /* sparc kernel supports console=tty[ab] parameter which is also
274 * passed to init, so catch it here */
275 else if ((s = getenv("console")) != NULL) {
276 /* remap tty[ab] to /dev/ttyS[01] */
277 if (strcmp(s, "ttya") == 0)
278 snprintf(console, sizeof(console) - 1, "%s", SERIAL_CON0);
279 else if (strcmp(s, "ttyb") == 0)
280 snprintf(console, sizeof(console) - 1, "%s", SERIAL_CON1);
284 /* 2.2 kernels: identify the real console backend and try to use it */
285 if (ioctl(0, TIOCGSERIAL, &sr) == 0) {
286 /* this is a serial console */
287 snprintf(console, sizeof(console) - 1, "/dev/ttyS%d", sr.line);
288 } else if (ioctl(0, VT_GETSTATE, &vt) == 0) {
289 /* this is linux virtual tty */
290 snprintf(console, sizeof(console) - 1, "/dev/tty%d",
293 snprintf(console, sizeof(console) - 1, "%s", _PATH_CONSOLE);
298 while ((fd = open(console, O_RDONLY | O_NONBLOCK)) < 0) {
299 /* Can't open selected console -- try /dev/console */
300 if (!tried_devcons) {
302 snprintf(console, sizeof(console) - 1, "%s", _PATH_CONSOLE);
305 /* Can't open selected console -- try vt1 */
306 if (!tried_vtprimary) {
308 snprintf(console, sizeof(console) - 1, "%s", VT_PRIMARY);
314 /* Perhaps we should panic here? */
315 snprintf(console, sizeof(console) - 1, "/dev/null");
317 /* check for serial console and disable logging to tty3 & running a
319 if (ioctl(0, TIOCGSERIAL, &sr) == 0) {
321 secondConsole = NULL;
322 /* Force the TERM setting to vt102 for serial console --
323 * iff TERM is set to linux (the default) */
324 if (strcmp( termType, "TERM=linux" ) == 0)
325 snprintf(termType, sizeof(termType) - 1, "TERM=vt102");
326 message(LOG | CONSOLE,
327 "serial console detected. Disabling virtual terminals.\r\n");
331 message(LOG, "console=%s\n", console);
334 static pid_t run(char *command, char *terminal, int get_enter)
341 static const char press_enter[] =
343 "\nPlease press Enter to activate this console. ";
344 char *environment[] = {
346 "PATH=/usr/bin:/bin:/usr/sbin:/sbin",
354 if ((pid = fork()) == 0) {
361 /* Reset signal handlers set for parent process */
362 signal(SIGUSR1, SIG_DFL);
363 signal(SIGUSR2, SIG_DFL);
364 signal(SIGINT, SIG_DFL);
365 signal(SIGTERM, SIG_DFL);
366 signal(SIGHUP, SIG_DFL);
368 if ((fd = device_open(terminal, O_RDWR)) < 0) {
369 message(LOG | CONSOLE, "Bummer, can't open %s\r\n", terminal);
375 tcsetpgrp(0, getpgrp());
378 if (get_enter == TRUE) {
380 * Save memory by not exec-ing anything large (like a shell)
381 * before the user wants it. This is critical if swap is not
382 * enabled and the system has low memory. Generally this will
383 * be run on the second virtual console, and the first will
384 * be allowed to start a shell or whatever an init script
389 pid_t shell_pgid = getpid();
390 message(LOG, "Waiting for enter to start '%s' (pid %d, console %s)\r\n",
391 command, shell_pgid, terminal);
393 write(fileno(stdout), press_enter, sizeof(press_enter) - 1);
394 read(fileno(stdin), &c, 1);
398 /* Log the process name and args */
399 message(LOG, "Starting pid %d, console %s: '%s'\r\n",
400 shell_pgid, terminal, command);
403 /* See if any special /bin/sh requiring characters are present */
404 if (strpbrk(command, "~`!$^&*()=|\\{}[];\"'<>?") != NULL) {
407 strcpy(buf, "exec ");
408 strncat(buf, command, sizeof(buf) - strlen(buf) - 1);
412 /* Convert command (char*) into cmd (char**, one word per string) */
413 for (tmpCmd = command, i = 0;
414 (tmpCmd = strsep(&command, " \t")) != NULL;) {
415 if (*tmpCmd != '\0') {
424 #if defined BB_FEATURE_INIT_COREDUMPS
427 if (stat (CORE_ENABLE_FLAG_FILE, &sb) == 0) {
429 limit.rlim_cur = RLIM_INFINITY;
430 limit.rlim_max = RLIM_INFINITY;
431 setrlimit(RLIMIT_CORE, &limit);
436 /* Now run it. The new program will take over this PID,
437 * so nothing further in init.c should be run. */
438 execve(cmd[0], cmd, environment);
440 /* We're still here? Some error happened. */
441 message(LOG | CONSOLE, "Bummer, could not run '%s': %s\n", cmd[0],
448 static int waitfor(char *command, char *terminal, int get_enter)
451 int pid = run(command, terminal, get_enter);
454 wpid = wait(&status);
455 if (wpid > 0 && wpid != pid) {
464 /* Make sure there is enough memory to do something useful. *
465 * Calls "swapon -a" if needed so be sure /etc/fstab is present... */
466 static void check_memory()
470 if (check_free_memory() > 1000)
473 if (stat("/etc/fstab", &statBuf) == 0) {
474 /* swapon -a requires /proc typically */
475 waitfor("mount proc /proc -t proc", console, FALSE);
476 /* Try to turn on swap */
477 waitfor("swapon -a", console, FALSE);
478 if (check_free_memory() < 1000)
486 "Sorry, your computer does not have enough memory.\r\n");
491 /* Run all commands to be run right before halt/reboot */
492 static void run_lastAction(void)
495 for (a = initActionList; a; a = a->nextPtr) {
496 if (a->action == CTRLALTDEL) {
497 waitfor(a->process, a->console, FALSE);
498 delete_initAction(a);
505 static void shutdown_system(void)
508 /* first disable our SIGHUP signal */
509 signal(SIGHUP, SIG_DFL);
511 /* Allow Ctrl-Alt-Del to reboot system. */
512 reboot(RB_ENABLE_CAD);
514 message(CONSOLE|LOG, "\r\nThe system is going down NOW !!\r\n");
517 /* Send signals to every process _except_ pid 1 */
518 message(CONSOLE|LOG, "Sending SIGTERM to all processes.\r\n");
523 message(CONSOLE|LOG, "Sending SIGKILL to all processes.\r\n");
527 /* run everything to be run at "ctrlaltdel" */
531 if (kernelVersion > 0 && kernelVersion <= 2 * 65536 + 2 * 256 + 11) {
532 /* bdflush, kupdate not needed for kernels >2.2.11 */
538 static void halt_signal(int sig)
542 "The system is halted. Press %s or turn off power\r\n",
543 (secondConsole == NULL) /* serial console */
544 ? "Reset" : "CTRL-ALT-DEL");
547 /* allow time for last message to reach serial console */
550 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,2,0)
552 reboot(RB_POWER_OFF);
555 reboot(RB_HALT_SYSTEM);
559 static void reboot_signal(int sig)
562 message(CONSOLE|LOG, "Please stand by while rebooting the system.\r\n");
565 /* allow time for last message to reach serial console */
572 #if defined BB_FEATURE_INIT_CHROOT
574 #if ! defined BB_FEATURE_USE_PROCFS
575 #error Sorry, I depend on the /proc filesystem right now.
578 static void check_chroot(int sig)
580 char *argv_init[2] = { "init", NULL, };
581 char *envp_init[3] = { "HOME=/", "TERM=linux", NULL, };
582 char rootpath[256], *tc;
585 if ((fd = open("/proc/sys/kernel/init-chroot", O_RDONLY)) == -1) {
587 "SIGHUP recived, but could not open proc file\r\n");
591 if (read(fd, rootpath, sizeof(rootpath)) == -1) {
593 "SIGHUP recived, but could not read proc file\r\n");
599 if (rootpath[0] == '\0') {
601 "SIGHUP recived, but new root is not valid: %s\r\n",
607 tc = strrchr(rootpath, '\n');
610 /* Ok, making it this far means we commit */
611 message(CONSOLE, "Please stand by, changing root to `%s'.\r\n",
614 /* kill all other programs first */
615 message(CONSOLE, "Sending SIGTERM to all processes.\r\n");
620 message(CONSOLE, "Sending SIGKILL to all processes.\r\n");
625 /* ok, we don't need /proc anymore. we also assume that the signaling
626 * process left the rest of the filesystems alone for us */
629 /* Ok, now we chroot. Hopefully we only have two things mounted, the
630 * new chroot'd mount point, and the old "/" mount. s,
631 * we go ahead and unmount the old "/". This should trigger the kernel
632 * to set things up the Right Way(tm). */
634 if (!chroot(rootpath))
637 /* If the chroot fails, we are already too far to turn back, so we
638 * continue and hope that executing init below will revive the system */
640 /* close all of our descriptors and open new ones */
644 open("/dev/console", O_RDWR, 0);
648 message(CONSOLE, "Executing real init...\r\n");
649 /* execute init in the (hopefully) new root */
650 execve("/sbin/init", argv_init, envp_init);
653 "ERROR: Could not exec new init. Press %s to reboot.\r\n",
654 (secondConsole == NULL) /* serial console */
655 ? "Reset" : "CTRL-ALT-DEL");
658 #endif /* BB_FEATURE_INIT_CHROOT */
660 #endif /* ! DEBUG_INIT */
662 void new_initAction(initActionEnum action, char *process, char *cons)
664 initAction *newAction;
669 /* If BusyBox detects that a serial console is in use,
670 * then entries not refering to the console or null devices will _not_ be run.
671 * The exception to this rule is the null device.
673 if (secondConsole == NULL && strcmp(cons, console)
674 && strcmp(cons, "/dev/null"))
677 newAction = calloc((size_t) (1), sizeof(initAction));
679 message(LOG | CONSOLE, "Memory allocation failure\n");
683 newAction->nextPtr = initActionList;
684 initActionList = newAction;
685 strncpy(newAction->process, process, 255);
686 newAction->action = action;
687 strncpy(newAction->console, cons, 255);
689 // message(LOG|CONSOLE, "process='%s' action='%d' console='%s'\n",
690 // newAction->process, newAction->action, newAction->console);
693 static void delete_initAction(initAction * action)
695 initAction *a, *b = NULL;
697 for (a = initActionList; a; b = a, a = a->nextPtr) {
700 initActionList = a->nextPtr;
702 b->nextPtr = a->nextPtr;
710 /* NOTE that if BB_FEATURE_USE_INITTAB is NOT defined,
711 * then parse_inittab() simply adds in some default
712 * actions(i.e runs INIT_SCRIPT and then starts a pair
713 * of "askfirst" shells). If BB_FEATURE_USE_INITTAB
714 * _is_ defined, but /etc/inittab is missing, this
715 * results in the same set of default behaviors.
717 void parse_inittab(void)
719 #ifdef BB_FEATURE_USE_INITTAB
721 char buf[256], lineAsRead[256], tmpConsole[256];
723 const struct initActionType *a = actions;
727 file = fopen(INITTAB, "r");
729 /* No inittab file -- set up some default behavior */
731 /* Swapoff on halt/reboot */
732 new_initAction(CTRLALTDEL, "/sbin/swapoff -a > /dev/null 2>&1", console);
733 /* Umount all filesystems on halt/reboot */
734 new_initAction(CTRLALTDEL, "/bin/umount -a -r > /dev/null 2>&1", console);
735 /* Askfirst shell on tty1 */
736 new_initAction(ASKFIRST, SHELL, console);
737 /* Askfirst shell on tty2 */
738 if (secondConsole != NULL)
739 new_initAction(ASKFIRST, SHELL, secondConsole);
741 new_initAction(SYSINIT, INIT_SCRIPT, console);
744 #ifdef BB_FEATURE_USE_INITTAB
747 while (fgets(buf, 255, file) != NULL) {
749 for (p = buf; *p == ' ' || *p == '\t'; p++);
750 if (*p == '#' || *p == '\n')
753 /* Trim the trailing \n */
754 q = strrchr(p, '\n');
758 /* Keep a copy around for posterity's sake (and error msgs) */
759 strcpy(lineAsRead, buf);
761 /* Grab the ID field */
764 if (p != NULL || *(p + 1) != '\0') {
769 /* Now peel off the process field from the end
772 if (q == NULL || *(q + 1) == '\0') {
773 message(LOG | CONSOLE, "Bad inittab entry: %s\n", lineAsRead);
780 /* Now peel off the action field */
782 if (r == NULL || *(r + 1) == '\0') {
783 message(LOG | CONSOLE, "Bad inittab entry: %s\n", lineAsRead);
789 /* Ok, now process it */
791 while (a->name != 0) {
792 if (strcmp(a->name, r) == 0) {
796 strcpy(tmpConsole, "/dev/");
797 strncat(tmpConsole, s, 200);
798 if (stat(tmpConsole, &statBuf) != 0) {
799 message(LOG | CONSOLE,
800 "device '%s' does not exist. Did you read the directions?\n",
806 new_initAction(a->action, q, s);
814 /* Choke on an unknown action */
815 message(LOG | CONSOLE, "Bad inittab entry: %s\n", lineAsRead);
819 #endif /* BB_FEATURE_USE_INITTAB */
824 extern int init_main(int argc, char **argv)
831 /* Expect to be invoked as init with PID=1 or be invoked as linuxrc */
833 #ifdef BB_FEATURE_LINUXRC
834 && strstr(argv[0], "linuxrc") == NULL
838 usage("init\n\nInit is the parent of all processes.\n\n"
839 "This version of init is designed to be run only "
842 /* Set up sig handlers -- be sure to
843 * clear all of these in run() */
844 signal(SIGUSR1, halt_signal);
845 signal(SIGUSR2, reboot_signal);
846 signal(SIGINT, reboot_signal);
847 signal(SIGTERM, reboot_signal);
848 #if defined BB_FEATURE_INIT_CHROOT
849 signal(SIGHUP, check_chroot);
852 /* Turn off rebooting via CTL-ALT-DEL -- we get a
853 * SIGINT on CAD so we can shut things down gracefully... */
854 reboot(RB_DISABLE_CAD);
857 /* Figure out what kernel this is running */
858 kernelVersion = get_kernel_revision();
860 /* Figure out where the default console should be */
863 /* Close whatever files are open, and reset the console. */
871 /* Make sure PATH is set to something sane */
872 putenv(_PATH_STDPATH);
877 #if ! defined BB_FEATURE_EXTRA_QUIET
881 "init started: BusyBox v%s (%s) multi-call binary\r\n",
885 #if ! defined BB_FEATURE_EXTRA_QUIET
889 "init(%d) started: BusyBox v%s (%s) multi-call binary\r\n",
890 getpid(), BB_VER, BB_BT);
894 /* Make sure there is enough memory to do something useful. */
897 /* Check if we are supposed to be in single user mode */
898 if (argc > 1 && (!strcmp(argv[1], "single") ||
899 !strcmp(argv[1], "-s") || !strcmp(argv[1], "1"))) {
900 /* Ask first then start a shell on tty2 */
901 if (secondConsole != NULL)
902 new_initAction(ASKFIRST, SHELL, secondConsole);
903 /* Start a shell on tty1 */
904 new_initAction(RESPAWN, SHELL, console);
906 /* Not in single user mode -- see what inittab says */
908 /* NOTE that if BB_FEATURE_USE_INITTAB is NOT defined,
909 * then parse_inittab() simply adds in some default
910 * actions(i.e runs INIT_SCRIPT and then starts a pair
911 * of "askfirst" shells */
915 /* Fix up argv[0] to be certain we claim to be init */
916 strncpy(argv[0], "init", strlen(argv[0])+1);
918 strncpy(argv[1], "\0", strlen(argv[1])+1);
920 /* Now run everything that needs to be run */
922 /* First run the sysinit command */
923 for (a = initActionList; a; a = a->nextPtr) {
924 if (a->action == SYSINIT) {
925 waitfor(a->process, a->console, FALSE);
926 /* Now remove the "sysinit" entry from the list */
927 delete_initAction(a);
930 /* Next run anything that wants to block */
931 for (a = initActionList; a; a = a->nextPtr) {
932 if (a->action == WAIT) {
933 waitfor(a->process, a->console, FALSE);
934 /* Now remove the "wait" entry from the list */
935 delete_initAction(a);
938 /* Next run anything to be run only once */
939 for (a = initActionList; a; a = a->nextPtr) {
940 if (a->action == ONCE) {
941 run(a->process, a->console, FALSE);
942 /* Now remove the "once" entry from the list */
943 delete_initAction(a);
946 /* If there is nothing else to do, stop */
947 if (initActionList == NULL) {
948 message(LOG | CONSOLE,
949 "No more tasks for init -- sleeping forever.\n");
954 /* Now run the looping stuff for the rest of forever */
956 for (a = initActionList; a; a = a->nextPtr) {
957 /* Only run stuff with pid==0. If they have
958 * a pid, that means they are still running */
962 /* run the respawn stuff */
963 a->pid = run(a->process, a->console, FALSE);
966 /* run the askfirst stuff */
967 a->pid = run(a->process, a->console, TRUE);
969 /* silence the compiler's incessant whining */
975 /* Wait for a child process to exit */
976 wpid = wait(&status);
978 /* Find out who died and clean up their corpse */
979 for (a = initActionList; a; a = a->nextPtr) {
980 if (a->pid == wpid) {
983 "Process '%s' (pid %d) exited. Scheduling it for restart.\n",
994 c-file-style: "linux"