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
35 #include <sys/types.h>
36 #include <sys/fcntl.h>
39 #include <sys/mount.h>
40 #include <sys/reboot.h>
41 #include <sys/kdaemon.h>
42 #include <sys/sysmacros.h>
43 #include <asm/types.h>
44 #include <linux/serial.h> /* for serial_struct */
45 #include <sys/vt.h> /* for vt_stat */
46 #include <sys/ioctl.h>
47 #include <linux/version.h>
49 #include <sys/syslog.h>
52 #if ! defined BB_FEATURE_USE_PROCFS
53 #error Sorry, I depend on the /proc filesystem right now.
56 #ifndef KERNEL_VERSION
57 #define KERNEL_VERSION(a,b,c) (((a) << 16) + ((b) << 8) + (c))
61 #define VT_PRIMARY "/dev/tty1" /* Primary virtual console */
62 #define VT_SECONDARY "/dev/tty2" /* Virtual console */
63 #define VT_LOG "/dev/tty3" /* Virtual console */
64 #define SERIAL_CON0 "/dev/ttyS0" /* Primary serial console */
65 #define SERIAL_CON1 "/dev/ttyS1" /* Serial console */
66 #define SHELL "/bin/sh" /* Default shell */
67 #define INITTAB "/etc/inittab" /* inittab file location */
69 #define INIT_SCRIPT "/etc/init.d/rcS" /* Default sysinit script. */
75 /* Allowed init action types */
84 /* And now a list of the actions we support in the version of init */
85 typedef struct initActionType {
87 initActionEnum action;
90 static const struct initActionType actions[] = {
93 {"askfirst", ASKFIRST},
99 /* Set up a linked list of initactions, to be read from inittab */
100 typedef struct initActionTag initAction;
101 struct initActionTag {
106 initActionEnum action;
108 initAction *initActionList = NULL;
111 static char *secondConsole = VT_SECONDARY;
112 static char *log = VT_LOG;
113 static int kernelVersion = 0;
114 static char termType[32] = "TERM=ansi";
115 static char console[32] = _PATH_CONSOLE;
118 /* print a message to the specified device:
119 * device may be bitwise-or'd from LOG | CONSOLE */
120 void message(int device, char *fmt, ...)
127 /* Log the message to syslogd */
131 va_start(arguments, fmt);
132 vsnprintf(msg, sizeof(msg), fmt, arguments);
134 openlog("init", 0, LOG_DAEMON);
135 syslog(LOG_DAEMON | LOG_NOTICE, msg);
139 static int log_fd = -1;
141 /* Take full control of the log tty, and never close it.
142 * It's mine, all mine! Muhahahaha! */
145 /* don't even try to log, because there is no such console */
147 /* log to main console instead */
149 } else if ((log_fd = device_open(log, O_RDWR | O_NDELAY)) < 0) {
151 fprintf(stderr, "Bummer, can't write to log on %s!\r\n", log);
156 if ((device & LOG) && (log_fd >= 0)) {
157 va_start(arguments, fmt);
158 vdprintf(log_fd, fmt, arguments);
163 if (device & CONSOLE) {
164 /* Always send console messages to /dev/console so people will see them. */
167 device_open(_PATH_CONSOLE,
168 O_WRONLY | O_NOCTTY | O_NDELAY)) >= 0) {
169 va_start(arguments, fmt);
170 vdprintf(fd, fmt, arguments);
174 fprintf(stderr, "Bummer, can't print: ");
175 va_start(arguments, fmt);
176 vfprintf(stderr, fmt, arguments);
184 /* Set terminal settings to reasonable defaults */
185 void set_term(int fd)
188 static const char control_characters[] = {
189 '\003', '\034', '\177', '\025', '\004', '\0',
190 '\1', '\0', '\021', '\023', '\032', '\0', '\022',
191 '\017', '\027', '\026', '\0'
196 /* set control chars */
197 memcpy(tty.c_cc, control_characters, sizeof(control_characters));
199 /* use line dicipline 0 */
202 /* Make it be sane */
203 //tty.c_cflag &= CBAUD|CBAUDEX|CSIZE|CSTOPB|PARENB|PARODD;
204 //tty.c_cflag |= HUPCL|CLOCAL;
207 tty.c_iflag = ICRNL | IXON | IXOFF;
210 tty.c_oflag = OPOST | ONLCR;
214 ISIG | ICANON | ECHO | ECHOE | ECHOK | ECHOCTL | ECHOKE | IEXTEN;
216 tcsetattr(fd, TCSANOW, &tty);
219 /* How much memory does this machine have? */
220 static int mem_total()
223 char *p = "/proc/meminfo";
225 const char pattern[] = "MemTotal:";
227 if ((f = fopen(p, "r")) < 0) {
228 message(LOG, "Error opening %s: %s\n", p, strerror(errno));
231 while (NULL != fgets(s, 79, f)) {
232 p = strstr(s, pattern);
235 return (atoi(p + strlen(pattern)));
241 static void console_init()
244 int tried_devcons = 0;
245 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);
270 /* 2.2 kernels: identify the real console backend and try to use it */
271 if (ioctl(0, TIOCGSERIAL, &sr) == 0) {
272 /* this is a serial console */
273 snprintf(console, sizeof(console) - 1, "/dev/ttyS%d", sr.line);
274 } else if (ioctl(0, VT_GETSTATE, &vt) == 0) {
275 /* this is linux virtual tty */
276 snprintf(console, sizeof(console) - 1, "/dev/tty%d",
279 snprintf(console, sizeof(console) - 1, "%s", _PATH_CONSOLE);
284 while ((fd = open(console, O_RDONLY | O_NONBLOCK)) < 0) {
285 /* Can't open selected console -- try /dev/console */
286 if (!tried_devcons) {
288 snprintf(console, sizeof(console) - 1, "%s", _PATH_CONSOLE);
291 /* Can't open selected console -- try vt1 */
292 if (!tried_vtprimary) {
294 snprintf(console, sizeof(console) - 1, "%s", VT_PRIMARY);
300 /* Perhaps we should panic here? */
301 snprintf(console, sizeof(console) - 1, "/dev/null");
303 /* check for serial console and disable logging to tty3 & running a
305 if (ioctl(0, TIOCGSERIAL, &sr) == 0) {
306 message(LOG | CONSOLE,
307 "serial console detected. Disabling virtual terminals.\r\n");
309 secondConsole = NULL;
313 message(LOG, "console=%s\n", console);
316 static pid_t run(char *command, char *terminal, int get_enter)
322 static const char press_enter[] =
324 "\nPlease press Enter to activate this console. ";
325 char *environment[] = {
327 "PATH=/usr/bin:/bin:/usr/sbin:/sbin",
335 if ((pid = fork()) == 0) {
336 pid_t shell_pgid = getpid();
344 /* Reset signal handlers set for parent process */
345 signal(SIGUSR1, SIG_DFL);
346 signal(SIGUSR2, SIG_DFL);
347 signal(SIGINT, SIG_DFL);
348 signal(SIGTERM, SIG_DFL);
349 signal(SIGHUP, SIG_DFL);
351 if ((fd = device_open(terminal, O_RDWR)) < 0) {
352 message(LOG | CONSOLE, "Bummer, can't open %s\r\n", terminal);
358 tcsetpgrp(0, getpgrp());
361 if (get_enter == TRUE) {
363 * Save memory by not exec-ing anything large (like a shell)
364 * before the user wants it. This is critical if swap is not
365 * enabled and the system has low memory. Generally this will
366 * be run on the second virtual console, and the first will
367 * be allowed to start a shell or whatever an init script
372 message(LOG, "Waiting for enter to start '%s' (pid %d, console %s)\r\n",
373 command, shell_pgid, terminal);
374 write(fileno(stdout), press_enter, sizeof(press_enter) - 1);
375 read(fileno(stdin), &c, 1);
378 /* Log the process name and args */
379 message(LOG, "Starting pid %d, console %s: '",
380 shell_pgid, terminal, command);
382 /* Convert command (char*) into cmd (char**, one word per string) */
383 for (tmpCmd = command, i = 0;
384 (tmpCmd = strsep(&command, " \t")) != NULL;) {
385 if (*tmpCmd != '\0') {
388 message(LOG, "%s ", tmpCmd);
395 message(LOG, "'\r\n");
397 /* Now run it. The new program will take over this PID,
398 * so nothing further in init.c should be run. */
399 execve(cmd[0], cmd, environment);
401 /* We're still here? Some error happened. */
402 message(LOG | CONSOLE, "Bummer, could not run '%s': %s\n", cmd[0],
409 static int waitfor(char *command, char *terminal, int get_enter)
412 int pid = run(command, terminal, get_enter);
415 wpid = wait(&status);
417 message(LOG, "Process '%s' (pid %d) exited.\n", command, wpid);
426 /* Make sure there is enough memory to do something useful. *
427 * Calls swapon if needed so be sure /proc is mounted. */
428 static void check_memory()
432 if (mem_total() > 3500)
435 if (stat("/etc/fstab", &statBuf) == 0) {
436 /* Try to turn on swap */
437 waitfor("/bin/swapon swapon -a", log, FALSE);
438 if (mem_total() < 3500)
446 "Sorry, your computer does not have enough memory.\r\n");
452 static void shutdown_system(void)
454 /* first disable our SIGHUP signal */
455 signal(SIGHUP, SIG_DFL);
457 /* Allow Ctrl-Alt-Del to reboot system. */
458 reboot(RB_ENABLE_CAD);
459 message(CONSOLE, "\r\nThe system is going down NOW !!\r\n");
462 /* Send signals to every process _except_ pid 1 */
463 message(CONSOLE, "Sending SIGTERM to all processes.\r\n");
468 message(CONSOLE, "Sending SIGKILL to all processes.\r\n");
472 message(CONSOLE, "Disabling swap.\r\n");
473 waitfor("swapoff -a", console, FALSE);
474 message(CONSOLE, "Unmounting filesystems.\r\n");
475 waitfor("umount -a -r", console, FALSE);
477 if (kernelVersion > 0 && kernelVersion <= 2 * 65536 + 2 * 256 + 11) {
478 /* bdflush, kupdate not needed for kernels >2.2.11 */
484 static void halt_signal(int sig)
488 "The system is halted. Press %s or turn off power\r\n",
489 (secondConsole == NULL) /* serial console */
490 ? "Reset" : "CTRL-ALT-DEL");
493 /* allow time for last message to reach serial console */
496 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,2,0)
498 reboot(RB_POWER_OFF);
501 reboot(RB_HALT_SYSTEM);
505 static void reboot_signal(int sig)
508 message(CONSOLE, "Please stand by while rebooting the system.\r\n");
511 /* allow time for last message to reach serial console */
518 #if defined BB_FEATURE_INIT_CHROOT
519 static void check_chroot(int sig)
521 char *argv_init[2] = { "init", NULL, };
522 char *envp_init[3] = { "HOME=/", "TERM=linux", NULL, };
523 char rootpath[256], *tc;
526 if ((fd = open("/proc/sys/kernel/init-chroot", O_RDONLY)) == -1) {
528 "SIGHUP recived, but could not open proc file\r\n");
532 if (read(fd, rootpath, sizeof(rootpath)) == -1) {
534 "SIGHUP recived, but could not read proc file\r\n");
540 if (rootpath[0] == '\0') {
542 "SIGHUP recived, but new root is not valid: %s\r\n",
548 tc = strrchr(rootpath, '\n');
551 /* Ok, making it this far means we commit */
552 message(CONSOLE, "Please stand by, changing root to `%s'.\r\n",
555 /* kill all other programs first */
556 message(CONSOLE, "Sending SIGTERM to all processes.\r\n");
561 message(CONSOLE, "Sending SIGKILL to all processes.\r\n");
566 /* ok, we don't need /proc anymore. we also assume that the signaling
567 * process left the rest of the filesystems alone for us */
570 /* Ok, now we chroot. Hopefully we only have two things mounted, the
571 * new chroot'd mount point, and the old "/" mount. s,
572 * we go ahead and unmount the old "/". This should trigger the kernel
573 * to set things up the Right Way(tm). */
575 if (!chroot(rootpath))
578 /* If the chroot fails, we are already too far to turn back, so we
579 * continue and hope that executing init below will revive the system */
581 /* close all of our descriptors and open new ones */
585 open("/dev/console", O_RDWR, 0);
589 message(CONSOLE, "Executing real init...\r\n");
590 /* execute init in the (hopefully) new root */
591 execve("/sbin/init", argv_init, envp_init);
594 "ERROR: Could not exec new init. Press %s to reboot.\r\n",
595 (secondConsole == NULL) /* serial console */
596 ? "Reset" : "CTRL-ALT-DEL");
599 #endif /* BB_FEATURE_INIT_CHROOT */
601 #endif /* ! DEBUG_INIT */
603 void new_initAction(initActionEnum action, char *process, char *cons)
605 initAction *newAction;
610 /* If BusyBox detects that a serial console is in use,
611 * then entries not refering to the console or null devices will _not_ be run.
612 * The exception to this rule is the null device.
614 if (secondConsole == NULL && strcmp(cons, console)
615 && strcmp(cons, "/dev/null"))
618 newAction = calloc((size_t) (1), sizeof(initAction));
620 message(LOG | CONSOLE, "Memory allocation failure\n");
624 newAction->nextPtr = initActionList;
625 initActionList = newAction;
626 strncpy(newAction->process, process, 255);
627 newAction->action = action;
628 strncpy(newAction->console, cons, 255);
630 // message(LOG|CONSOLE, "process='%s' action='%d' console='%s'\n",
631 // newAction->process, newAction->action, newAction->console);
634 void delete_initAction(initAction * action)
636 initAction *a, *b = NULL;
638 for (a = initActionList; a; b = a, a = a->nextPtr) {
641 initActionList = a->nextPtr;
643 b->nextPtr = a->nextPtr;
651 /* NOTE that if BB_FEATURE_USE_INITTAB is NOT defined,
652 * then parse_inittab() simply adds in some default
653 * actions(i.e runs INIT_SCRIPT and then starts a pair
654 * of "askfirst" shells). If BB_FEATURE_USE_INITTAB
655 * _is_ defined, but /etc/inittab is missing, this
656 * results in the same set of default behaviors.
658 void parse_inittab(void)
660 #ifdef BB_FEATURE_USE_INITTAB
662 char buf[256], lineAsRead[256], tmpConsole[256];
664 const struct initActionType *a = actions;
668 file = fopen(INITTAB, "r");
670 /* No inittab file -- set up some default behavior */
672 /* Askfirst shell on tty1 */
673 new_initAction(ASKFIRST, SHELL, console);
674 /* Askfirst shell on tty2 */
675 if (secondConsole != NULL)
676 new_initAction(ASKFIRST, SHELL, secondConsole);
678 new_initAction(SYSINIT, INIT_SCRIPT, console);
681 #ifdef BB_FEATURE_USE_INITTAB
684 while (fgets(buf, 255, file) != NULL) {
686 for (p = buf; *p == ' ' || *p == '\t'; p++);
687 if (*p == '#' || *p == '\n')
690 /* Trim the trailing \n */
691 q = strrchr(p, '\n');
695 /* Keep a copy around for posterity's sake (and error msgs) */
696 strcpy(lineAsRead, buf);
698 /* Grab the ID field */
701 if (p != NULL || *(p + 1) != '\0') {
706 /* Now peal off the process field from the end
709 if (q == NULL || *(q + 1) == '\0') {
710 message(LOG | CONSOLE, "Bad inittab entry: %s\n", lineAsRead);
717 /* Now peal off the action field */
719 if (r == NULL || *(r + 1) == '\0') {
720 message(LOG | CONSOLE, "Bad inittab entry: %s\n", lineAsRead);
726 /* Ok, now process it */
728 while (a->name != 0) {
729 if (strcmp(a->name, r) == 0) {
733 strcpy(tmpConsole, "/dev/");
734 strncat(tmpConsole, s, 200);
735 if (stat(tmpConsole, &statBuf) != 0) {
736 message(LOG | CONSOLE,
737 "device '%s' does not exist. Did you read the directions?\n",
743 new_initAction(a->action, q, s);
751 /* Choke on an unknown action */
752 message(LOG | CONSOLE, "Bad inittab entry: %s\n", lineAsRead);
759 extern int init_main(int argc, char **argv)
766 /* Expect to be PID 1 if we are run as init (not linuxrc) */
767 if (getpid() != 1 && strstr(argv[0], "init") != NULL) {
768 usage("init\n\nInit is the parent of all processes.\n\n"
769 "This version of init is designed to be run only by the kernel\n");
771 /* Fix up argv[0] to be certain we claim to be init */
772 strncpy(argv[0], "init", strlen(argv[0]));
774 /* Set up sig handlers -- be sure to
775 * clear all of these in run() */
776 signal(SIGUSR1, halt_signal);
777 signal(SIGUSR2, reboot_signal);
778 signal(SIGINT, reboot_signal);
779 signal(SIGTERM, reboot_signal);
780 #if defined BB_FEATURE_INIT_CHROOT
781 signal(SIGHUP, check_chroot);
784 /* Turn off rebooting via CTL-ALT-DEL -- we get a
785 * SIGINT on CAD so we can shut things down gracefully... */
786 reboot(RB_DISABLE_CAD);
789 /* Figure out where the default console should be */
792 /* Close whatever files are open, and reset the console. */
799 /* Make sure PATH is set to something sane */
800 putenv(_PATH_STDPATH);
804 message(LOG | CONSOLE,
805 "init started: BusyBox v%s (%s) multi-call binary\r\n",
808 message(LOG | CONSOLE,
809 "init(%d) started: BusyBox v%s (%s) multi-call binary\r\n",
810 getpid(), BB_VER, BB_BT);
815 if (mount("proc", "/proc", "proc", 0, 0) == 0) {
816 message(LOG | CONSOLE, "Mounting /proc: done.\n");
817 kernelVersion = get_kernel_revision();
819 message(LOG | CONSOLE, "Mounting /proc: failed!\n");
821 /* Make sure there is enough memory to do something useful. */
824 /* Check if we are supposed to be in single user mode */
825 if (argc > 1 && (!strcmp(argv[1], "single") ||
826 !strcmp(argv[1], "-s") || !strcmp(argv[1], "1"))) {
827 /* Ask first then start a shell on tty2 */
828 if (secondConsole != NULL)
829 new_initAction(ASKFIRST, SHELL, secondConsole);
830 /* Start a shell on tty1 */
831 new_initAction(RESPAWN, SHELL, console);
833 /* Not in single user mode -- see what inittab says */
835 /* NOTE that if BB_FEATURE_USE_INITTAB is NOT defined,
836 * then parse_inittab() simply adds in some default
837 * actions(i.e runs INIT_SCRIPT and then starts a pair
838 * of "askfirst" shells */
842 /* Now run everything that needs to be run */
844 /* First run the sysinit command */
845 for (a = initActionList; a; a = a->nextPtr) {
846 if (a->action == SYSINIT) {
847 waitfor(a->process, a->console, FALSE);
848 /* Now remove the "sysinit" entry from the list */
849 delete_initAction(a);
852 /* Next run anything that wants to block */
853 for (a = initActionList; a; a = a->nextPtr) {
854 if (a->action == WAIT) {
855 waitfor(a->process, a->console, FALSE);
856 /* Now remove the "wait" entry from the list */
857 delete_initAction(a);
860 /* Next run anything to be run only once */
861 for (a = initActionList; a; a = a->nextPtr) {
862 if (a->action == ONCE) {
863 run(a->process, a->console, FALSE);
864 /* Now remove the "once" entry from the list */
865 delete_initAction(a);
868 /* If there is nothing else to do, stop */
869 if (initActionList == NULL) {
870 message(LOG | CONSOLE,
871 "No more tasks for init -- sleeping forever.\n");
876 /* Now run the looping stuff for the rest of forever */
878 for (a = initActionList; a; a = a->nextPtr) {
879 /* Only run stuff with pid==0. If they have
880 * a pid, that means they are still running */
884 /* run the respawn stuff */
885 a->pid = run(a->process, a->console, FALSE);
888 /* run the askfirst stuff */
889 a->pid = run(a->process, a->console, TRUE);
891 /* silence the compiler's incessant whining */
897 /* Wait for a child process to exit */
898 wpid = wait(&status);
900 /* Find out who died and clean up their corpse */
901 for (a = initActionList; a; a = a->nextPtr) {
902 if (a->pid == wpid) {
905 "Process '%s' (pid %d) exited. Scheduling it for restart.\n",