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.
40 #include <sys/types.h>
41 #include <sys/fcntl.h>
44 #include <sys/mount.h>
45 #include <sys/reboot.h>
46 #include <sys/kdaemon.h>
47 #include <sys/sysmacros.h>
48 #include <asm/types.h>
49 #include <linux/serial.h> /* for serial_struct */
50 #include <sys/vt.h> /* for vt_stat */
51 #include <sys/ioctl.h>
52 #include <sys/sysinfo.h> /* For check_free_memory() */
53 #include <linux/version.h>
55 #include <sys/syslog.h>
58 #ifndef KERNEL_VERSION
59 #define KERNEL_VERSION(a,b,c) (((a) << 16) + ((b) << 8) + (c))
63 #define VT_PRIMARY "/dev/tty1" /* Primary virtual console */
64 #define VT_SECONDARY "/dev/tty2" /* Virtual console */
65 #define VT_LOG "/dev/tty3" /* Virtual console */
66 #define SERIAL_CON0 "/dev/ttyS0" /* Primary serial console */
67 #define SERIAL_CON1 "/dev/ttyS1" /* Serial console */
68 #define SHELL "/bin/sh" /* Default shell */
69 #define INITTAB "/etc/inittab" /* inittab file location */
71 #define INIT_SCRIPT "/etc/init.d/rcS" /* Default sysinit script. */
77 /* Allowed init action types */
87 /* And now a list of the actions we support in the version of init */
88 typedef struct initActionType {
90 initActionEnum action;
93 static const struct initActionType actions[] = {
96 {"askfirst", ASKFIRST},
99 {"ctrlaltdel", CTRLALTDEL},
103 /* Set up a linked list of initactions, to be read from inittab */
104 typedef struct initActionTag initAction;
105 struct initActionTag {
110 initActionEnum action;
112 initAction *initActionList = NULL;
115 static char *secondConsole = VT_SECONDARY;
116 static char *log = VT_LOG;
117 static int kernelVersion = 0;
118 static char termType[32] = "TERM=linux";
119 static char console[32] = _PATH_CONSOLE;
120 static void delete_initAction(initAction * action);
123 /* print a message to the specified device:
124 * device may be bitwise-or'd from LOG | CONSOLE */
125 void message(int device, char *fmt, ...)
132 /* Log the message to syslogd */
136 va_start(arguments, fmt);
137 vsnprintf(msg, sizeof(msg), fmt, arguments);
139 openlog("init", 0, LOG_USER);
140 syslog(LOG_USER|LOG_INFO, msg);
144 static int log_fd = -1;
146 /* Take full control of the log tty, and never close it.
147 * It's mine, all mine! Muhahahaha! */
150 /* don't even try to log, because there is no such console */
152 /* log to main console instead */
154 } else if ((log_fd = device_open(log, O_RDWR|O_NDELAY)) < 0) {
156 fprintf(stderr, "Bummer, can't write to log on %s!\r\n", log);
162 if ((device & LOG) && (log_fd >= 0)) {
163 va_start(arguments, fmt);
164 vdprintf(log_fd, fmt, arguments);
169 if (device & CONSOLE) {
170 /* Always send console messages to /dev/console so people will see them. */
173 device_open(_PATH_CONSOLE,
174 O_WRONLY | O_NOCTTY | O_NDELAY)) >= 0) {
175 va_start(arguments, fmt);
176 vdprintf(fd, fmt, arguments);
180 fprintf(stderr, "Bummer, can't print: ");
181 va_start(arguments, fmt);
182 vfprintf(stderr, fmt, arguments);
190 /* Set terminal settings to reasonable defaults */
191 void set_term(int fd)
194 static const char control_characters[] = {
195 '\003', '\034', '\177', '\025', '\004', '\0',
196 '\1', '\0', '\021', '\023', '\032', '\0', '\022',
197 '\017', '\027', '\026', '\0'
202 /* set control chars */
203 memcpy(tty.c_cc, control_characters, sizeof(control_characters));
205 /* use line dicipline 0 */
208 /* Make it be sane */
209 //tty.c_cflag &= CBAUD|CBAUDEX|CSIZE|CSTOPB|PARENB|PARODD;
210 //tty.c_cflag |= HUPCL|CLOCAL;
213 tty.c_iflag = ICRNL | IXON | IXOFF;
216 tty.c_oflag = OPOST | ONLCR;
220 ISIG | ICANON | ECHO | ECHOE | ECHOK | ECHOCTL | ECHOKE | IEXTEN;
222 tcsetattr(fd, TCSANOW, &tty);
225 /* How much memory does this machine have? */
226 static int check_free_memory()
231 if (sysinfo(&info) != 0) {
232 message(LOG, "Error checking free memory: %s\n", strerror(errno));
236 return(info.freeram/1024);
240 static void console_init()
243 int tried_devcons = 0;
244 int tried_vtprimary = 0;
246 struct serial_struct sr;
249 if ((s = getenv("TERM")) != NULL) {
250 snprintf(termType, sizeof(termType) - 1, "TERM=%s", s);
253 if ((s = getenv("CONSOLE")) != NULL) {
254 snprintf(console, sizeof(console) - 1, "%s", s);
257 /* sparc kernel supports console=tty[ab] parameter which is also
258 * passed to init, so catch it here */
259 else if ((s = getenv("console")) != NULL) {
260 /* remap tty[ab] to /dev/ttyS[01] */
261 if (strcmp(s, "ttya") == 0)
262 snprintf(console, sizeof(console) - 1, "%s", SERIAL_CON0);
263 else if (strcmp(s, "ttyb") == 0)
264 snprintf(console, sizeof(console) - 1, "%s", SERIAL_CON1);
268 /* 2.2 kernels: identify the real console backend and try to use it */
269 if (ioctl(0, TIOCGSERIAL, &sr) == 0) {
270 /* this is a serial console */
271 snprintf(console, sizeof(console) - 1, "/dev/ttyS%d", sr.line);
272 } else if (ioctl(0, VT_GETSTATE, &vt) == 0) {
273 /* this is linux virtual tty */
274 snprintf(console, sizeof(console) - 1, "/dev/tty%d",
277 snprintf(console, sizeof(console) - 1, "%s", _PATH_CONSOLE);
282 while ((fd = open(console, O_RDONLY | O_NONBLOCK)) < 0) {
283 /* Can't open selected console -- try /dev/console */
284 if (!tried_devcons) {
286 snprintf(console, sizeof(console) - 1, "%s", _PATH_CONSOLE);
289 /* Can't open selected console -- try vt1 */
290 if (!tried_vtprimary) {
292 snprintf(console, sizeof(console) - 1, "%s", VT_PRIMARY);
298 /* Perhaps we should panic here? */
299 snprintf(console, sizeof(console) - 1, "/dev/null");
301 /* check for serial console and disable logging to tty3 & running a
303 if (ioctl(0, TIOCGSERIAL, &sr) == 0) {
305 secondConsole = NULL;
306 /* Force the TERM setting to vt102 for serial console --
307 * iff TERM is set to linux (the default) */
308 if (strcmp( termType, "TERM=linux" ) == 0)
309 snprintf(termType, sizeof(termType) - 1, "TERM=vt102");
310 message(LOG | CONSOLE,
311 "serial console detected. Disabling virtual terminals.\r\n");
315 message(LOG, "console=%s\n", console);
318 static pid_t run(char *command, char *terminal, int get_enter)
325 static const char press_enter[] =
327 "\nPlease press Enter to activate this console. ";
328 char *environment[] = {
330 "PATH=/usr/bin:/bin:/usr/sbin:/sbin",
338 if ((pid = fork()) == 0) {
340 pid_t shell_pgid = getpid();
349 /* Reset signal handlers set for parent process */
350 signal(SIGUSR1, SIG_DFL);
351 signal(SIGUSR2, SIG_DFL);
352 signal(SIGINT, SIG_DFL);
353 signal(SIGTERM, SIG_DFL);
354 signal(SIGHUP, SIG_DFL);
356 if ((fd = device_open(terminal, O_RDWR)) < 0) {
357 message(LOG | CONSOLE, "Bummer, can't open %s\r\n", terminal);
363 tcsetpgrp(0, getpgrp());
366 if (get_enter == TRUE) {
368 * Save memory by not exec-ing anything large (like a shell)
369 * before the user wants it. This is critical if swap is not
370 * enabled and the system has low memory. Generally this will
371 * be run on the second virtual console, and the first will
372 * be allowed to start a shell or whatever an init script
378 message(LOG, "Waiting for enter to start '%s' (pid %d, console %s)\r\n",
379 command, shell_pgid, terminal);
381 write(fileno(stdout), press_enter, sizeof(press_enter) - 1);
382 read(fileno(stdin), &c, 1);
386 /* Log the process name and args */
387 message(LOG, "Starting pid %d, console %s: '%s'\r\n",
388 shell_pgid, terminal, command);
391 /* See if any special /bin/sh requiring characters are present */
392 if (strpbrk(command, "~`!$^&*()=|\\{}[];\"'<>?") != NULL) {
395 strcpy(buf, "exec ");
396 strncat(buf, command, sizeof(buf) - strlen(buf) - 1);
400 /* Convert command (char*) into cmd (char**, one word per string) */
401 for (tmpCmd = command, i = 0;
402 (tmpCmd = strsep(&command, " \t")) != NULL;) {
403 if (*tmpCmd != '\0') {
412 /* Now run it. The new program will take over this PID,
413 * so nothing further in init.c should be run. */
414 execve(cmd[0], cmd, environment);
416 /* We're still here? Some error happened. */
417 message(LOG | CONSOLE, "Bummer, could not run '%s': %s\n", cmd[0],
424 static int waitfor(char *command, char *terminal, int get_enter)
427 int pid = run(command, terminal, get_enter);
430 wpid = wait(&status);
431 if (wpid > 0 && wpid != pid) {
440 /* Make sure there is enough memory to do something useful. *
441 * Calls "swapon -a" if needed so be sure /etc/fstab is present... */
442 static void check_memory()
446 if (check_free_memory() > 1000)
449 if (stat("/etc/fstab", &statBuf) == 0) {
450 /* Try to turn on swap */
451 system("/sbin/swapon -a");
452 if (check_free_memory() < 1000)
460 "Sorry, your computer does not have enough memory.\r\n");
465 /* Run all commands to be run right before halt/reboot */
466 static void run_lastAction(void)
469 for (a = initActionList; a; a = a->nextPtr) {
470 if (a->action == CTRLALTDEL) {
471 waitfor(a->process, a->console, FALSE);
472 delete_initAction(a);
479 static void shutdown_system(void)
482 /* first disable our SIGHUP signal */
483 signal(SIGHUP, SIG_DFL);
485 /* Allow Ctrl-Alt-Del to reboot system. */
486 reboot(RB_ENABLE_CAD);
488 message(CONSOLE|LOG, "\r\nThe system is going down NOW !!\r\n");
491 /* Send signals to every process _except_ pid 1 */
492 message(CONSOLE|LOG, "Sending SIGTERM to all processes.\r\n");
497 message(CONSOLE|LOG, "Sending SIGKILL to all processes.\r\n");
501 /* run everything to be run at "ctrlaltdel" */
505 if (kernelVersion > 0 && kernelVersion <= 2 * 65536 + 2 * 256 + 11) {
506 /* bdflush, kupdate not needed for kernels >2.2.11 */
512 static void halt_signal(int sig)
516 "The system is halted. Press %s or turn off power\r\n",
517 (secondConsole == NULL) /* serial console */
518 ? "Reset" : "CTRL-ALT-DEL");
521 /* allow time for last message to reach serial console */
524 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,2,0)
526 reboot(RB_POWER_OFF);
529 reboot(RB_HALT_SYSTEM);
533 static void reboot_signal(int sig)
536 message(CONSOLE|LOG, "Please stand by while rebooting the system.\r\n");
539 /* allow time for last message to reach serial console */
546 #if defined BB_FEATURE_INIT_CHROOT
548 #if ! defined BB_FEATURE_USE_PROCFS
549 #error Sorry, I depend on the /proc filesystem right now.
552 static void check_chroot(int sig)
554 char *argv_init[2] = { "init", NULL, };
555 char *envp_init[3] = { "HOME=/", "TERM=linux", NULL, };
556 char rootpath[256], *tc;
559 if ((fd = open("/proc/sys/kernel/init-chroot", O_RDONLY)) == -1) {
561 "SIGHUP recived, but could not open proc file\r\n");
565 if (read(fd, rootpath, sizeof(rootpath)) == -1) {
567 "SIGHUP recived, but could not read proc file\r\n");
573 if (rootpath[0] == '\0') {
575 "SIGHUP recived, but new root is not valid: %s\r\n",
581 tc = strrchr(rootpath, '\n');
584 /* Ok, making it this far means we commit */
585 message(CONSOLE, "Please stand by, changing root to `%s'.\r\n",
588 /* kill all other programs first */
589 message(CONSOLE, "Sending SIGTERM to all processes.\r\n");
594 message(CONSOLE, "Sending SIGKILL to all processes.\r\n");
599 /* ok, we don't need /proc anymore. we also assume that the signaling
600 * process left the rest of the filesystems alone for us */
603 /* Ok, now we chroot. Hopefully we only have two things mounted, the
604 * new chroot'd mount point, and the old "/" mount. s,
605 * we go ahead and unmount the old "/". This should trigger the kernel
606 * to set things up the Right Way(tm). */
608 if (!chroot(rootpath))
611 /* If the chroot fails, we are already too far to turn back, so we
612 * continue and hope that executing init below will revive the system */
614 /* close all of our descriptors and open new ones */
618 open("/dev/console", O_RDWR, 0);
622 message(CONSOLE, "Executing real init...\r\n");
623 /* execute init in the (hopefully) new root */
624 execve("/sbin/init", argv_init, envp_init);
627 "ERROR: Could not exec new init. Press %s to reboot.\r\n",
628 (secondConsole == NULL) /* serial console */
629 ? "Reset" : "CTRL-ALT-DEL");
632 #endif /* BB_FEATURE_INIT_CHROOT */
634 #endif /* ! DEBUG_INIT */
636 void new_initAction(initActionEnum action, char *process, char *cons)
638 initAction *newAction;
643 /* If BusyBox detects that a serial console is in use,
644 * then entries not refering to the console or null devices will _not_ be run.
645 * The exception to this rule is the null device.
647 if (secondConsole == NULL && strcmp(cons, console)
648 && strcmp(cons, "/dev/null"))
651 newAction = calloc((size_t) (1), sizeof(initAction));
653 message(LOG | CONSOLE, "Memory allocation failure\n");
657 newAction->nextPtr = initActionList;
658 initActionList = newAction;
659 strncpy(newAction->process, process, 255);
660 newAction->action = action;
661 strncpy(newAction->console, cons, 255);
663 // message(LOG|CONSOLE, "process='%s' action='%d' console='%s'\n",
664 // newAction->process, newAction->action, newAction->console);
667 static void delete_initAction(initAction * action)
669 initAction *a, *b = NULL;
671 for (a = initActionList; a; b = a, a = a->nextPtr) {
674 initActionList = a->nextPtr;
676 b->nextPtr = a->nextPtr;
684 /* NOTE that if BB_FEATURE_USE_INITTAB is NOT defined,
685 * then parse_inittab() simply adds in some default
686 * actions(i.e runs INIT_SCRIPT and then starts a pair
687 * of "askfirst" shells). If BB_FEATURE_USE_INITTAB
688 * _is_ defined, but /etc/inittab is missing, this
689 * results in the same set of default behaviors.
691 void parse_inittab(void)
693 #ifdef BB_FEATURE_USE_INITTAB
695 char buf[256], lineAsRead[256], tmpConsole[256];
697 const struct initActionType *a = actions;
701 file = fopen(INITTAB, "r");
703 /* No inittab file -- set up some default behavior */
705 /* Swapoff on halt/reboot */
706 new_initAction(CTRLALTDEL, "/sbin/swapoff -a > /dev/null 2>&1", console);
707 /* Umount all filesystems on halt/reboot */
708 new_initAction(CTRLALTDEL, "/bin/umount -a -r > /dev/null 2>&1", console);
709 /* Askfirst shell on tty1 */
710 new_initAction(ASKFIRST, SHELL, console);
711 /* Askfirst shell on tty2 */
712 if (secondConsole != NULL)
713 new_initAction(ASKFIRST, SHELL, secondConsole);
715 new_initAction(SYSINIT, INIT_SCRIPT, console);
718 #ifdef BB_FEATURE_USE_INITTAB
721 while (fgets(buf, 255, file) != NULL) {
723 for (p = buf; *p == ' ' || *p == '\t'; p++);
724 if (*p == '#' || *p == '\n')
727 /* Trim the trailing \n */
728 q = strrchr(p, '\n');
732 /* Keep a copy around for posterity's sake (and error msgs) */
733 strcpy(lineAsRead, buf);
735 /* Grab the ID field */
738 if (p != NULL || *(p + 1) != '\0') {
743 /* Now peal off the process field from the end
746 if (q == NULL || *(q + 1) == '\0') {
747 message(LOG | CONSOLE, "Bad inittab entry: %s\n", lineAsRead);
754 /* Now peal off the action field */
756 if (r == NULL || *(r + 1) == '\0') {
757 message(LOG | CONSOLE, "Bad inittab entry: %s\n", lineAsRead);
763 /* Ok, now process it */
765 while (a->name != 0) {
766 if (strcmp(a->name, r) == 0) {
770 strcpy(tmpConsole, "/dev/");
771 strncat(tmpConsole, s, 200);
772 if (stat(tmpConsole, &statBuf) != 0) {
773 message(LOG | CONSOLE,
774 "device '%s' does not exist. Did you read the directions?\n",
780 new_initAction(a->action, q, s);
788 /* Choke on an unknown action */
789 message(LOG | CONSOLE, "Bad inittab entry: %s\n", lineAsRead);
798 extern int init_main(int argc, char **argv)
805 /* Expect to be invoked as init with PID=1 or be invoked as linuxrc */
807 #ifdef BB_FEATURE_LINUXRC
808 && strstr(argv[0], "linuxrc") == NULL
812 usage("init\n\nInit is the parent of all processes.\n\n"
813 "This version of init is designed to be run only "
816 /* Set up sig handlers -- be sure to
817 * clear all of these in run() */
818 signal(SIGUSR1, halt_signal);
819 signal(SIGUSR2, reboot_signal);
820 signal(SIGINT, reboot_signal);
821 signal(SIGTERM, reboot_signal);
822 #if defined BB_FEATURE_INIT_CHROOT
823 signal(SIGHUP, check_chroot);
826 /* Turn off rebooting via CTL-ALT-DEL -- we get a
827 * SIGINT on CAD so we can shut things down gracefully... */
828 reboot(RB_DISABLE_CAD);
831 /* Figure out where the default console should be */
834 /* Close whatever files are open, and reset the console. */
841 /* Make sure PATH is set to something sane */
842 putenv(_PATH_STDPATH);
847 "init started: BusyBox v%s (%s) multi-call binary\r\n",
851 "init(%d) started: BusyBox v%s (%s) multi-call binary\r\n",
852 getpid(), BB_VER, BB_BT);
856 /* Make sure there is enough memory to do something useful. */
859 /* Check if we are supposed to be in single user mode */
860 if (argc > 1 && (!strcmp(argv[1], "single") ||
861 !strcmp(argv[1], "-s") || !strcmp(argv[1], "1"))) {
862 /* Ask first then start a shell on tty2 */
863 if (secondConsole != NULL)
864 new_initAction(ASKFIRST, SHELL, secondConsole);
865 /* Start a shell on tty1 */
866 new_initAction(RESPAWN, SHELL, console);
868 /* Not in single user mode -- see what inittab says */
870 /* NOTE that if BB_FEATURE_USE_INITTAB is NOT defined,
871 * then parse_inittab() simply adds in some default
872 * actions(i.e runs INIT_SCRIPT and then starts a pair
873 * of "askfirst" shells */
877 /* Fix up argv[0] to be certain we claim to be init */
878 strncpy(argv[0], "init", strlen(argv[0])+1);
880 strncpy(argv[1], "\0", strlen(argv[1])+1);
882 /* Now run everything that needs to be run */
884 /* First run the sysinit command */
885 for (a = initActionList; a; a = a->nextPtr) {
886 if (a->action == SYSINIT) {
887 waitfor(a->process, a->console, FALSE);
888 /* Now remove the "sysinit" entry from the list */
889 delete_initAction(a);
892 /* Next run anything that wants to block */
893 for (a = initActionList; a; a = a->nextPtr) {
894 if (a->action == WAIT) {
895 waitfor(a->process, a->console, FALSE);
896 /* Now remove the "wait" entry from the list */
897 delete_initAction(a);
900 /* Next run anything to be run only once */
901 for (a = initActionList; a; a = a->nextPtr) {
902 if (a->action == ONCE) {
903 run(a->process, a->console, FALSE);
904 /* Now remove the "once" entry from the list */
905 delete_initAction(a);
908 /* If there is nothing else to do, stop */
909 if (initActionList == NULL) {
910 message(LOG | CONSOLE,
911 "No more tasks for init -- sleeping forever.\n");
916 /* Now run the looping stuff for the rest of forever */
918 for (a = initActionList; a; a = a->nextPtr) {
919 /* Only run stuff with pid==0. If they have
920 * a pid, that means they are still running */
924 /* run the respawn stuff */
925 a->pid = run(a->process, a->console, FALSE);
928 /* run the askfirst stuff */
929 a->pid = run(a->process, a->console, TRUE);
931 /* silence the compiler's incessant whining */
937 /* Wait for a child process to exit */
938 wpid = wait(&status);
940 /* Find out who died and clean up their corpse */
941 for (a = initActionList; a; a = a->nextPtr) {
942 if (a->pid == wpid) {
945 "Process '%s' (pid %d) exited. Scheduling it for restart.\n",
956 c-file-style: "linux"