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, ...)
145 /* Log the message to syslogd */
149 va_start(arguments, fmt);
150 vsnprintf(msg, sizeof(msg), fmt, arguments);
152 openlog("init", 0, LOG_USER);
153 syslog(LOG_USER|LOG_INFO, msg);
157 static int log_fd = -1;
159 /* Take full control of the log tty, and never close it.
160 * It's mine, all mine! Muhahahaha! */
163 /* don't even try to log, because there is no such console */
165 /* log to main console instead */
167 } else if ((log_fd = device_open(log, O_RDWR|O_NDELAY)) < 0) {
169 fprintf(stderr, "Bummer, can't write to log on %s!\r\n", log);
175 if ((device & LOG) && (log_fd >= 0)) {
176 va_start(arguments, fmt);
177 vdprintf(log_fd, fmt, arguments);
182 if (device & CONSOLE) {
183 /* Always send console messages to /dev/console so people will see them. */
186 device_open(_PATH_CONSOLE,
187 O_WRONLY | O_NOCTTY | O_NDELAY)) >= 0) {
188 va_start(arguments, fmt);
189 vdprintf(fd, fmt, arguments);
193 fprintf(stderr, "Bummer, can't print: ");
194 va_start(arguments, fmt);
195 vfprintf(stderr, fmt, arguments);
203 /* Set terminal settings to reasonable defaults */
204 void set_term(int fd)
210 /* set control chars */
211 tty.c_cc[VINTR] = 3; /* C-c */
212 tty.c_cc[VQUIT] = 28; /* C-\ */
213 tty.c_cc[VERASE] = 127; /* C-? */
214 tty.c_cc[VKILL] = 21; /* C-u */
215 tty.c_cc[VEOF] = 4; /* C-d */
216 tty.c_cc[VSTART] = 17; /* C-q */
217 tty.c_cc[VSTOP] = 19; /* C-s */
218 tty.c_cc[VSUSP] = 26; /* C-z */
220 /* use line dicipline 0 */
223 /* Make it be sane */
224 tty.c_cflag &= CBAUD|CBAUDEX|CSIZE|CSTOPB|PARENB|PARODD;
225 tty.c_cflag |= HUPCL|CLOCAL;
228 tty.c_iflag = ICRNL | IXON | IXOFF;
231 tty.c_oflag = OPOST | ONLCR;
235 ISIG | ICANON | ECHO | ECHOE | ECHOK | ECHOCTL | ECHOKE | IEXTEN;
237 tcsetattr(fd, TCSANOW, &tty);
240 /* How much memory does this machine have? */
241 static int check_free_memory()
246 if (sysinfo(&info) != 0) {
247 message(LOG, "Error checking free memory: %s\n", strerror(errno));
251 return((info.totalram+info.totalswap)/1024);
254 static void console_init()
257 int tried_devcons = 0;
258 int tried_vtprimary = 0;
260 struct serial_struct sr;
263 if ((s = getenv("TERM")) != NULL) {
264 snprintf(termType, sizeof(termType) - 1, "TERM=%s", s);
267 if ((s = getenv("CONSOLE")) != NULL) {
268 snprintf(console, sizeof(console) - 1, "%s", s);
271 /* sparc kernel supports console=tty[ab] parameter which is also
272 * passed to init, so catch it here */
273 else if ((s = getenv("console")) != NULL) {
274 /* remap tty[ab] to /dev/ttyS[01] */
275 if (strcmp(s, "ttya") == 0)
276 snprintf(console, sizeof(console) - 1, "%s", SERIAL_CON0);
277 else if (strcmp(s, "ttyb") == 0)
278 snprintf(console, sizeof(console) - 1, "%s", SERIAL_CON1);
282 /* 2.2 kernels: identify the real console backend and try to use it */
283 if (ioctl(0, TIOCGSERIAL, &sr) == 0) {
284 /* this is a serial console */
285 snprintf(console, sizeof(console) - 1, "/dev/ttyS%d", sr.line);
286 } else if (ioctl(0, VT_GETSTATE, &vt) == 0) {
287 /* this is linux virtual tty */
288 snprintf(console, sizeof(console) - 1, "/dev/tty%d",
291 snprintf(console, sizeof(console) - 1, "%s", _PATH_CONSOLE);
296 while ((fd = open(console, O_RDONLY | O_NONBLOCK)) < 0) {
297 /* Can't open selected console -- try /dev/console */
298 if (!tried_devcons) {
300 snprintf(console, sizeof(console) - 1, "%s", _PATH_CONSOLE);
303 /* Can't open selected console -- try vt1 */
304 if (!tried_vtprimary) {
306 snprintf(console, sizeof(console) - 1, "%s", VT_PRIMARY);
312 /* Perhaps we should panic here? */
313 snprintf(console, sizeof(console) - 1, "/dev/null");
315 /* check for serial console and disable logging to tty3 & running a
317 if (ioctl(0, TIOCGSERIAL, &sr) == 0) {
319 secondConsole = NULL;
320 /* Force the TERM setting to vt102 for serial console --
321 * iff TERM is set to linux (the default) */
322 if (strcmp( termType, "TERM=linux" ) == 0)
323 snprintf(termType, sizeof(termType) - 1, "TERM=vt102");
324 message(LOG | CONSOLE,
325 "serial console detected. Disabling virtual terminals.\r\n");
329 message(LOG, "console=%s\n", console);
332 static pid_t run(char *command, char *terminal, int get_enter)
339 static const char press_enter[] =
341 "\nPlease press Enter to activate this console. ";
342 char *environment[] = {
344 "PATH=/usr/bin:/bin:/usr/sbin:/sbin",
352 if ((pid = fork()) == 0) {
359 /* Reset signal handlers set for parent process */
360 signal(SIGUSR1, SIG_DFL);
361 signal(SIGUSR2, SIG_DFL);
362 signal(SIGINT, SIG_DFL);
363 signal(SIGTERM, SIG_DFL);
364 signal(SIGHUP, SIG_DFL);
366 if ((fd = device_open(terminal, O_RDWR)) < 0) {
367 message(LOG | CONSOLE, "Bummer, can't open %s\r\n", terminal);
373 tcsetpgrp(0, getpgrp());
376 if (get_enter == TRUE) {
378 * Save memory by not exec-ing anything large (like a shell)
379 * before the user wants it. This is critical if swap is not
380 * enabled and the system has low memory. Generally this will
381 * be run on the second virtual console, and the first will
382 * be allowed to start a shell or whatever an init script
387 pid_t shell_pgid = getpid();
388 message(LOG, "Waiting for enter to start '%s' (pid %d, console %s)\r\n",
389 command, shell_pgid, terminal);
391 write(fileno(stdout), press_enter, sizeof(press_enter) - 1);
392 read(fileno(stdin), &c, 1);
396 /* Log the process name and args */
397 message(LOG, "Starting pid %d, console %s: '%s'\r\n",
398 shell_pgid, terminal, command);
401 /* See if any special /bin/sh requiring characters are present */
402 if (strpbrk(command, "~`!$^&*()=|\\{}[];\"'<>?") != NULL) {
405 strcpy(buf, "exec ");
406 strncat(buf, command, sizeof(buf) - strlen(buf) - 1);
410 /* Convert command (char*) into cmd (char**, one word per string) */
411 for (tmpCmd = command, i = 0;
412 (tmpCmd = strsep(&command, " \t")) != NULL;) {
413 if (*tmpCmd != '\0') {
422 #if defined BB_FEATURE_INIT_COREDUMPS
425 if (stat (CORE_ENABLE_FLAG_FILE, &sb) == 0) {
427 limit.rlim_cur = RLIM_INFINITY;
428 limit.rlim_max = RLIM_INFINITY;
429 setrlimit(RLIMIT_CORE, &limit);
434 /* Now run it. The new program will take over this PID,
435 * so nothing further in init.c should be run. */
436 execve(cmd[0], cmd, environment);
438 /* We're still here? Some error happened. */
439 message(LOG | CONSOLE, "Bummer, could not run '%s': %s\n", cmd[0],
446 static int waitfor(char *command, char *terminal, int get_enter)
449 int pid = run(command, terminal, get_enter);
452 wpid = wait(&status);
453 if (wpid > 0 && wpid != pid) {
462 /* Make sure there is enough memory to do something useful. *
463 * Calls "swapon -a" if needed so be sure /etc/fstab is present... */
464 static void check_memory()
468 if (check_free_memory() > 1000)
471 if (stat("/etc/fstab", &statBuf) == 0) {
472 /* Try to turn on swap */
473 system("/sbin/swapon -a");
474 if (check_free_memory() < 1000)
482 "Sorry, your computer does not have enough memory.\r\n");
487 /* Run all commands to be run right before halt/reboot */
488 static void run_lastAction(void)
491 for (a = initActionList; a; a = a->nextPtr) {
492 if (a->action == CTRLALTDEL) {
493 waitfor(a->process, a->console, FALSE);
494 delete_initAction(a);
501 static void shutdown_system(void)
504 /* first disable our SIGHUP signal */
505 signal(SIGHUP, SIG_DFL);
507 /* Allow Ctrl-Alt-Del to reboot system. */
508 reboot(RB_ENABLE_CAD);
510 message(CONSOLE|LOG, "\r\nThe system is going down NOW !!\r\n");
513 /* Send signals to every process _except_ pid 1 */
514 message(CONSOLE|LOG, "Sending SIGTERM to all processes.\r\n");
519 message(CONSOLE|LOG, "Sending SIGKILL to all processes.\r\n");
523 /* run everything to be run at "ctrlaltdel" */
527 if (kernelVersion > 0 && kernelVersion <= 2 * 65536 + 2 * 256 + 11) {
528 /* bdflush, kupdate not needed for kernels >2.2.11 */
534 static void halt_signal(int sig)
538 "The system is halted. Press %s or turn off power\r\n",
539 (secondConsole == NULL) /* serial console */
540 ? "Reset" : "CTRL-ALT-DEL");
543 /* allow time for last message to reach serial console */
546 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,2,0)
548 reboot(RB_POWER_OFF);
551 reboot(RB_HALT_SYSTEM);
555 static void reboot_signal(int sig)
558 message(CONSOLE|LOG, "Please stand by while rebooting the system.\r\n");
561 /* allow time for last message to reach serial console */
568 #if defined BB_FEATURE_INIT_CHROOT
570 #if ! defined BB_FEATURE_USE_PROCFS
571 #error Sorry, I depend on the /proc filesystem right now.
574 static void check_chroot(int sig)
576 char *argv_init[2] = { "init", NULL, };
577 char *envp_init[3] = { "HOME=/", "TERM=linux", NULL, };
578 char rootpath[256], *tc;
581 if ((fd = open("/proc/sys/kernel/init-chroot", O_RDONLY)) == -1) {
583 "SIGHUP recived, but could not open proc file\r\n");
587 if (read(fd, rootpath, sizeof(rootpath)) == -1) {
589 "SIGHUP recived, but could not read proc file\r\n");
595 if (rootpath[0] == '\0') {
597 "SIGHUP recived, but new root is not valid: %s\r\n",
603 tc = strrchr(rootpath, '\n');
606 /* Ok, making it this far means we commit */
607 message(CONSOLE, "Please stand by, changing root to `%s'.\r\n",
610 /* kill all other programs first */
611 message(CONSOLE, "Sending SIGTERM to all processes.\r\n");
616 message(CONSOLE, "Sending SIGKILL to all processes.\r\n");
621 /* ok, we don't need /proc anymore. we also assume that the signaling
622 * process left the rest of the filesystems alone for us */
625 /* Ok, now we chroot. Hopefully we only have two things mounted, the
626 * new chroot'd mount point, and the old "/" mount. s,
627 * we go ahead and unmount the old "/". This should trigger the kernel
628 * to set things up the Right Way(tm). */
630 if (!chroot(rootpath))
633 /* If the chroot fails, we are already too far to turn back, so we
634 * continue and hope that executing init below will revive the system */
636 /* close all of our descriptors and open new ones */
640 open("/dev/console", O_RDWR, 0);
644 message(CONSOLE, "Executing real init...\r\n");
645 /* execute init in the (hopefully) new root */
646 execve("/sbin/init", argv_init, envp_init);
649 "ERROR: Could not exec new init. Press %s to reboot.\r\n",
650 (secondConsole == NULL) /* serial console */
651 ? "Reset" : "CTRL-ALT-DEL");
654 #endif /* BB_FEATURE_INIT_CHROOT */
656 #endif /* ! DEBUG_INIT */
658 void new_initAction(initActionEnum action, char *process, char *cons)
660 initAction *newAction;
665 /* If BusyBox detects that a serial console is in use,
666 * then entries not refering to the console or null devices will _not_ be run.
667 * The exception to this rule is the null device.
669 if (secondConsole == NULL && strcmp(cons, console)
670 && strcmp(cons, "/dev/null"))
673 newAction = calloc((size_t) (1), sizeof(initAction));
675 message(LOG | CONSOLE, "Memory allocation failure\n");
679 newAction->nextPtr = initActionList;
680 initActionList = newAction;
681 strncpy(newAction->process, process, 255);
682 newAction->action = action;
683 strncpy(newAction->console, cons, 255);
685 // message(LOG|CONSOLE, "process='%s' action='%d' console='%s'\n",
686 // newAction->process, newAction->action, newAction->console);
689 static void delete_initAction(initAction * action)
691 initAction *a, *b = NULL;
693 for (a = initActionList; a; b = a, a = a->nextPtr) {
696 initActionList = a->nextPtr;
698 b->nextPtr = a->nextPtr;
706 /* NOTE that if BB_FEATURE_USE_INITTAB is NOT defined,
707 * then parse_inittab() simply adds in some default
708 * actions(i.e runs INIT_SCRIPT and then starts a pair
709 * of "askfirst" shells). If BB_FEATURE_USE_INITTAB
710 * _is_ defined, but /etc/inittab is missing, this
711 * results in the same set of default behaviors.
713 void parse_inittab(void)
715 #ifdef BB_FEATURE_USE_INITTAB
717 char buf[256], lineAsRead[256], tmpConsole[256];
719 const struct initActionType *a = actions;
723 file = fopen(INITTAB, "r");
725 /* No inittab file -- set up some default behavior */
727 /* Swapoff on halt/reboot */
728 new_initAction(CTRLALTDEL, "/sbin/swapoff -a > /dev/null 2>&1", console);
729 /* Umount all filesystems on halt/reboot */
730 new_initAction(CTRLALTDEL, "/bin/umount -a -r > /dev/null 2>&1", console);
731 /* Askfirst shell on tty1 */
732 new_initAction(ASKFIRST, SHELL, console);
733 /* Askfirst shell on tty2 */
734 if (secondConsole != NULL)
735 new_initAction(ASKFIRST, SHELL, secondConsole);
737 new_initAction(SYSINIT, INIT_SCRIPT, console);
740 #ifdef BB_FEATURE_USE_INITTAB
743 while (fgets(buf, 255, file) != NULL) {
745 for (p = buf; *p == ' ' || *p == '\t'; p++);
746 if (*p == '#' || *p == '\n')
749 /* Trim the trailing \n */
750 q = strrchr(p, '\n');
754 /* Keep a copy around for posterity's sake (and error msgs) */
755 strcpy(lineAsRead, buf);
757 /* Grab the ID field */
760 if (p != NULL || *(p + 1) != '\0') {
765 /* Now peel off the process field from the end
768 if (q == NULL || *(q + 1) == '\0') {
769 message(LOG | CONSOLE, "Bad inittab entry: %s\n", lineAsRead);
776 /* Now peel off the action field */
778 if (r == NULL || *(r + 1) == '\0') {
779 message(LOG | CONSOLE, "Bad inittab entry: %s\n", lineAsRead);
785 /* Ok, now process it */
787 while (a->name != 0) {
788 if (strcmp(a->name, r) == 0) {
792 strcpy(tmpConsole, "/dev/");
793 strncat(tmpConsole, s, 200);
794 if (stat(tmpConsole, &statBuf) != 0) {
795 message(LOG | CONSOLE,
796 "device '%s' does not exist. Did you read the directions?\n",
802 new_initAction(a->action, q, s);
810 /* Choke on an unknown action */
811 message(LOG | CONSOLE, "Bad inittab entry: %s\n", lineAsRead);
815 #endif /* BB_FEATURE_USE_INITTAB */
820 extern int init_main(int argc, char **argv)
827 /* Expect to be invoked as init with PID=1 or be invoked as linuxrc */
829 #ifdef BB_FEATURE_LINUXRC
830 && strstr(argv[0], "linuxrc") == NULL
834 usage("init\n\nInit is the parent of all processes.\n\n"
835 "This version of init is designed to be run only "
838 /* Set up sig handlers -- be sure to
839 * clear all of these in run() */
840 signal(SIGUSR1, halt_signal);
841 signal(SIGUSR2, reboot_signal);
842 signal(SIGINT, reboot_signal);
843 signal(SIGTERM, reboot_signal);
844 #if defined BB_FEATURE_INIT_CHROOT
845 signal(SIGHUP, check_chroot);
848 /* Turn off rebooting via CTL-ALT-DEL -- we get a
849 * SIGINT on CAD so we can shut things down gracefully... */
850 reboot(RB_DISABLE_CAD);
853 /* Figure out what kernel this is running */
854 kernelVersion = get_kernel_revision();
856 /* Figure out where the default console should be */
859 /* Close whatever files are open, and reset the console. */
867 /* Make sure PATH is set to something sane */
868 putenv(_PATH_STDPATH);
873 #if ! defined BB_FEATURE_EXTRA_QUIET
877 "init started: BusyBox v%s (%s) multi-call binary\r\n",
881 #if ! defined BB_FEATURE_EXTRA_QUIET
885 "init(%d) started: BusyBox v%s (%s) multi-call binary\r\n",
886 getpid(), BB_VER, BB_BT);
890 /* Make sure there is enough memory to do something useful. */
893 /* Check if we are supposed to be in single user mode */
894 if (argc > 1 && (!strcmp(argv[1], "single") ||
895 !strcmp(argv[1], "-s") || !strcmp(argv[1], "1"))) {
896 /* Ask first then start a shell on tty2 */
897 if (secondConsole != NULL)
898 new_initAction(ASKFIRST, SHELL, secondConsole);
899 /* Start a shell on tty1 */
900 new_initAction(RESPAWN, SHELL, console);
902 /* Not in single user mode -- see what inittab says */
904 /* NOTE that if BB_FEATURE_USE_INITTAB is NOT defined,
905 * then parse_inittab() simply adds in some default
906 * actions(i.e runs INIT_SCRIPT and then starts a pair
907 * of "askfirst" shells */
911 /* Fix up argv[0] to be certain we claim to be init */
912 strncpy(argv[0], "init", strlen(argv[0])+1);
914 strncpy(argv[1], "\0", strlen(argv[1])+1);
916 /* Now run everything that needs to be run */
918 /* First run the sysinit command */
919 for (a = initActionList; a; a = a->nextPtr) {
920 if (a->action == SYSINIT) {
921 waitfor(a->process, a->console, FALSE);
922 /* Now remove the "sysinit" entry from the list */
923 delete_initAction(a);
926 /* Next run anything that wants to block */
927 for (a = initActionList; a; a = a->nextPtr) {
928 if (a->action == WAIT) {
929 waitfor(a->process, a->console, FALSE);
930 /* Now remove the "wait" entry from the list */
931 delete_initAction(a);
934 /* Next run anything to be run only once */
935 for (a = initActionList; a; a = a->nextPtr) {
936 if (a->action == ONCE) {
937 run(a->process, a->console, FALSE);
938 /* Now remove the "once" entry from the list */
939 delete_initAction(a);
942 /* If there is nothing else to do, stop */
943 if (initActionList == NULL) {
944 message(LOG | CONSOLE,
945 "No more tasks for init -- sleeping forever.\n");
950 /* Now run the looping stuff for the rest of forever */
952 for (a = initActionList; a; a = a->nextPtr) {
953 /* Only run stuff with pid==0. If they have
954 * a pid, that means they are still running */
958 /* run the respawn stuff */
959 a->pid = run(a->process, a->console, FALSE);
962 /* run the askfirst stuff */
963 a->pid = run(a->process, a->console, TRUE);
965 /* silence the compiler's incessant whining */
971 /* Wait for a child process to exit */
972 wpid = wait(&status);
974 /* Find out who died and clean up their corpse */
975 for (a = initActionList; a; a = a->nextPtr) {
976 if (a->pid == wpid) {
979 "Process '%s' (pid %d) exited. Scheduling it for restart.\n",
990 c-file-style: "linux"