2 * Mini init implementation for busybox
5 * Copyright (C) 1995, 1996 by Bruce Perens <bruce@pixar.com>.
6 * Adjusted by so many folks, it's impossible to keep track.
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * General Public License for more details.
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
34 #include <sys/types.h>
35 #include <sys/fcntl.h>
38 #include <sys/mount.h>
39 #include <sys/reboot.h>
40 #include <sys/kdaemon.h>
41 #include <sys/sysmacros.h>
42 #include <linux/serial.h> /* for serial_struct */
43 #include <sys/vt.h> /* for vt_stat */
44 #include <sys/ioctl.h>
45 #include <linux/version.h>
47 #include <sys/syslog.h>
50 #if ! defined BB_FEATURE_USE_PROCFS
51 #error Sorry, I depend on the /proc filesystem right now.
54 #ifndef KERNEL_VERSION
55 #define KERNEL_VERSION(a,b,c) (((a) << 16) + ((b) << 8) + (c))
59 #define VT_PRIMARY "/dev/tty1" /* Primary virtual console */
60 #define VT_SECONDARY "/dev/tty2" /* Virtual console */
61 #define VT_LOG "/dev/tty3" /* Virtual console */
62 #define SERIAL_CON0 "/dev/ttyS0" /* Primary serial console */
63 #define SERIAL_CON1 "/dev/ttyS1" /* Serial console */
64 #define SHELL "/bin/sh" /* Default shell */
65 #define INITTAB "/etc/inittab" /* inittab file location */
67 #define INIT_SCRIPT "/etc/init.d/rcS" /* Default sysinit script. */
73 /* Allowed init action types */
82 /* And now a list of the actions we support in the version of init */
83 typedef struct initActionType{
85 initActionEnum action;
88 static const struct initActionType actions[] = {
91 {"askfirst", ASKFIRST},
97 /* Set up a linked list of initactions, to be read from inittab */
98 typedef struct initActionTag initAction;
99 struct initActionTag {
104 initActionEnum action;
106 initAction* initActionList = NULL;
109 static char *console = _PATH_CONSOLE;
110 static char *second_console = VT_SECONDARY;
111 static char *log = VT_LOG;
112 static int kernel_version = 0;
115 /* try to open up the specified device */
116 int device_open(char *device, int mode)
120 m = mode | O_NONBLOCK;
122 /* Retry up to 5 times */
123 for (f = 0; f < 5; f++)
124 if ((fd = open(device, m)) >= 0)
128 /* Reset original flags. */
130 fcntl(fd, F_SETFL, mode);
134 /* print a message to the specified device:
135 * device may be bitwise-or'd from LOG | CONSOLE */
136 void message(int device, char *fmt, ...)
143 /* Log the message to syslogd */
146 va_start(arguments, fmt);
147 vsnprintf(msg, sizeof(msg), fmt, arguments);
149 syslog(LOG_DAEMON|LOG_NOTICE, msg);
153 static int log_fd=-1;
155 /* Take full control of the log tty, and never close it.
156 * It's mine, all mine! Muhahahaha! */
159 /* don't even try to log, because there is no such console */
161 /* log to main console instead */
164 else if ((log_fd = device_open(log, O_RDWR|O_NDELAY)) < 0) {
166 fprintf(stderr, "Bummer, can't write to log on %s!\r\n", log);
171 if ( (device & LOG) && (log_fd >= 0) ) {
172 va_start(arguments, fmt);
173 vdprintf(log_fd, fmt, arguments);
178 if (device & CONSOLE) {
179 /* Always send console messages to /dev/console so people will see them. */
180 if ((fd = device_open(_PATH_CONSOLE, O_WRONLY|O_NOCTTY|O_NDELAY)) >= 0) {
181 va_start(arguments, fmt);
182 vdprintf(fd, fmt, arguments);
186 fprintf(stderr, "Bummer, can't print: ");
187 va_start(arguments, fmt);
188 vfprintf(stderr, fmt, arguments);
196 /* Set terminal settings to reasonable defaults */
197 void set_term( int fd)
200 static const char control_characters[] = {
201 '\003', '\034', '\177', '\025', '\004', '\0',
202 '\1', '\0', '\021', '\023', '\032', '\0', '\022',
203 '\017', '\027', '\026', '\0'
208 /* set control chars */
209 memcpy(tty.c_cc, control_characters, sizeof(control_characters));
211 /* use line dicipline 0 */
214 /* Make it be sane */
215 //tty.c_cflag &= CBAUD|CBAUDEX|CSIZE|CSTOPB|PARENB|PARODD;
216 //tty.c_cflag |= HUPCL|CLOCAL;
219 tty.c_iflag = ICRNL|IXON|IXOFF;
222 tty.c_oflag = OPOST|ONLCR;
225 tty.c_lflag = ISIG|ICANON|ECHO|ECHOE|ECHOK|ECHOCTL|ECHOKE|IEXTEN;
227 tcsetattr(fd, TCSANOW, &tty);
230 /* How much memory does this machine have? */
231 static int mem_total()
234 char *p = "/proc/meminfo";
236 const char pattern[] = "MemTotal:";
238 if ((f = fopen(p, "r")) < 0) {
239 message(LOG, "Error opening %s: %s\n", p, strerror( errno));
242 while (NULL != fgets(s, 79, f)) {
243 p = strstr(s, pattern);
246 return (atoi(p + strlen(pattern)));
252 static void console_init()
255 int tried_devcons = 0;
256 int tried_vtprimary = 0;
257 struct serial_struct sr;
260 if ((s = getenv("CONSOLE")) != NULL) {
264 /* sparc kernel supports console=tty[ab] parameter which is also
265 * passed to init, so catch it here */
266 else if ((s = getenv("console")) != NULL) {
267 /* remap tty[ab] to /dev/ttyS[01] */
268 if (strcmp( s, "ttya" )==0)
269 console = SERIAL_CON0;
270 else if (strcmp( s, "ttyb" )==0)
271 console = SERIAL_CON1;
276 static char the_console[13];
278 console = the_console;
279 /* 2.2 kernels: identify the real console backend and try to use it */
280 if (ioctl(0, TIOCGSERIAL, &sr) == 0) {
281 /* this is a serial console */
282 snprintf( the_console, sizeof the_console, "/dev/ttyS%d", sr.line );
284 else if (ioctl(0, VT_GETSTATE, &vt) == 0) {
285 /* this is linux virtual tty */
286 snprintf( the_console, sizeof the_console, "/dev/tty%d", vt.v_active );
288 console = _PATH_CONSOLE;
293 while ((fd = open(console, O_RDONLY | O_NONBLOCK)) < 0) {
294 /* Can't open selected console -- try /dev/console */
295 if (!tried_devcons) {
297 console = _PATH_CONSOLE;
300 /* Can't open selected console -- try vt1 */
301 if (!tried_vtprimary) {
303 console = VT_PRIMARY;
309 /* Perhaps we should panic here? */
310 console = "/dev/null";
312 /* check for serial console and disable logging to tty3 & running a
314 if (ioctl(0,TIOCGSERIAL,&sr) == 0) {
315 message(LOG|CONSOLE, "serial console detected. Disabling 2nd virtual terminal.\r\n", console );
317 second_console = NULL;
321 message(LOG, "console=%s\n", console );
324 static pid_t run(char* command,
325 char *terminal, int get_enter)
331 static const char press_enter[] =
332 "\nPlease press Enter to activate this console. ";
334 if ((pid = fork()) == 0) {
336 pid_t shell_pgid = getpid ();
344 if ((fd=device_open(terminal, O_RDWR)) < 0) {
345 message(LOG|CONSOLE, "Bummer, can't open %s\r\n", terminal);
351 tcsetpgrp (fd, getpgrp());
353 /* Reset signal handlers set for parent process */
354 signal(SIGUSR1, SIG_DFL);
355 signal(SIGUSR2, SIG_DFL);
356 signal(SIGINT, SIG_DFL);
357 signal(SIGTERM, SIG_DFL);
360 if (get_enter==TRUE) {
362 * Save memory by not exec-ing anything large (like a shell)
363 * before the user wants it. This is critical if swap is not
364 * enabled and the system has low memory. Generally this will
365 * be run on the second virtual console, and the first will
366 * be allowed to start a shell or whatever an init script
370 message(LOG, "Waiting for enter to start '%s' (pid %d, console %s)\r\n",
371 command, shell_pgid, terminal );
372 write(fileno(stdout), press_enter, sizeof(press_enter) - 1);
373 read(fileno(stdin), &c, 1);
376 /* Convert command (char*) into cmd (char**, one word per string) */
377 for (tmpCmd=command, i=0; (tmpCmd=strsep(&command, " \t")) != NULL;) {
378 if (*tmpCmd != '\0') {
386 /* Log the process name and args */
387 message(LOG, "Starting pid %d, console %s: '%s'\r\n",
388 shell_pgid, terminal, cmd[0]);
390 /* Now run it. The new program will take over this PID,
391 * so nothing further in init.c should be run. */
394 /* We're still here? Some error happened. */
395 message(LOG|CONSOLE, "Bummer, could not run '%s': %s\n", cmd[0],
402 static int waitfor(char* command,
403 char *terminal, int get_enter)
406 int pid = run( command, terminal, get_enter);
409 wpid = wait(&status);
411 message(LOG, "Process '%s' (pid %d) exited.\n",
421 /* Make sure there is enough memory to do something useful. *
422 * Calls swapon if needed so be sure /proc is mounted. */
423 static void check_memory()
427 if (mem_total() > 3500)
430 if (stat("/etc/fstab", &statBuf) == 0) {
431 /* Try to turn on swap */
432 waitfor("/bin/swapon swapon -a", log, FALSE);
433 if (mem_total() < 3500)
440 message(CONSOLE, "Sorry, your computer does not have enough memory.\r\n");
445 static void shutdown_system(void)
447 /* Allow Ctrl-Alt-Del to reboot system. */
448 reboot(RB_ENABLE_CAD);
449 message(CONSOLE, "\r\nThe system is going down NOW !!\r\n");
452 /* Send signals to every process _except_ pid 1 */
453 message(CONSOLE, "Sending SIGHUP to all processes.\r\n");
458 message(CONSOLE, "Sending SIGKILL to all processes.\r\n");
462 message(CONSOLE, "Disabling swap.\r\n");
463 waitfor( "swapoff -a", console, FALSE);
464 message(CONSOLE, "Unmounting filesystems.\r\n");
465 waitfor("umount -a", console, FALSE);
467 if (kernel_version > 0 && kernel_version <= 2 * 65536 + 2 * 256 + 11) {
468 /* bdflush, kupdate not needed for kernels >2.2.11 */
474 static void halt_signal(int sig)
478 "The system is halted. Press CTRL-ALT-DEL or turn off power\r\n");
480 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,2,0)
482 reboot(RB_POWER_OFF);
485 reboot(RB_HALT_SYSTEM);
489 static void reboot_signal(int sig)
492 message(CONSOLE, "Please stand by while rebooting the system.\r\n");
500 void new_initAction (initActionEnum action,
501 char* process, char* cons)
503 initAction* newAction;
505 /* If BusyBox detects that a serial console is in use,
506 * then entries containing non-empty id fields will _not_ be run.
508 if (second_console == NULL && *cons != '\0') {
512 newAction = calloc ((size_t)(1), sizeof(initAction));
514 message(LOG|CONSOLE,"Memory allocation failure\n");
517 newAction->nextPtr = initActionList;
518 initActionList = newAction;
519 strncpy( newAction->process, process, 255);
520 newAction->action = action;
522 strncpy(newAction->console, cons, 255);
524 strncpy(newAction->console, console, 255);
526 message(LOG|CONSOLE, "process='%s' action='%d' console='%s'\n",
527 newAction->process, newAction->action, newAction->console);
530 void delete_initAction (initAction *action)
532 initAction *a, *b=NULL;
533 for( a=initActionList ; a; b=a, a=a->nextPtr) {
534 if (a == action && b != NULL) {
535 b->nextPtr=a->nextPtr;
542 /* NOTE that if BB_FEATURE_USE_INITTAB is NOT defined,
543 * then parse_inittab() simply adds in some default
544 * actions(i.e runs INIT_SCRIPT and then starts a pair
545 * of "askfirst" shells. If BB_FEATURE_USE_INITTAB
546 * _is_ defined, but /etc/inittab is missing == same
549 void parse_inittab(void)
551 #ifdef BB_FEATURE_USE_INITTAB
553 char buf[256], lineAsRead[256], tmpConsole[256];
555 const struct initActionType *a = actions;
559 file = fopen(INITTAB, "r");
561 /* No inittab file -- set up some default behavior */
563 /* Askfirst shell on tty1 */
564 new_initAction( ASKFIRST, SHELL, console );
565 /* Askfirst shell on tty2 */
566 if (second_console != NULL)
567 new_initAction( ASKFIRST, SHELL, second_console );
569 new_initAction( SYSINIT, INIT_SCRIPT, console );
572 #ifdef BB_FEATURE_USE_INITTAB
575 while ( fgets(buf, 255, file) != NULL) {
577 for(p = buf; *p == ' ' || *p == '\t'; p++);
578 if (*p == '#' || *p == '\n') continue;
580 /* Trim the trailing \n */
581 q = strrchr( p, '\n');
585 /* Keep a copy around for posterity's sake (and error msgs) */
586 strcpy(lineAsRead, buf);
588 /* Grab the ID field */
591 if ( p != NULL || *(p+1) != '\0' ) {
596 /* Now peal off the process field from the end
598 q = strrchr( p, ':');
599 if ( q == NULL || *(q+1) == '\0' ) {
600 message(LOG|CONSOLE,"Bad inittab entry: %s\n", lineAsRead);
607 /* Now peal off the action field */
608 r = strrchr( p, ':');
609 if ( r == NULL || *(r+1) == '\0') {
610 message(LOG|CONSOLE,"Bad inittab entry: %s\n", lineAsRead);
616 /* Ok, now process it */
618 while (a->name != 0) {
619 if (strcmp(a->name, r) == 0) {
622 strcpy(tmpConsole, "/dev/");
623 strncat(tmpConsole, s, 200);
624 if (stat(tmpConsole, &statBuf) != 0) {
625 message(LOG|CONSOLE, "device '%s' does not exist. Did you read the directions?\n", tmpConsole);
630 new_initAction( a->action, q, s);
638 /* Choke on an unknown action */
639 message(LOG|CONSOLE, "Bad inittab entry: %s\n", lineAsRead);
646 extern int init_main(int argc, char **argv)
653 /* Expect to be PID 1 iff we are run as init (not linuxrc) */
654 if (getpid() != 1 && strstr(argv[0], "init")!=NULL ) {
655 usage( "init\n\nInit is the parent of all processes.\n\n"
656 "This version of init is designed to be run only by the kernel\n");
659 /* from the controlling terminal */
662 /* Set up sig handlers -- be sure to clear all of these in run() */
663 signal(SIGUSR1, halt_signal);
664 signal(SIGUSR2, reboot_signal);
665 signal(SIGINT, reboot_signal);
666 signal(SIGTERM, reboot_signal);
668 /* Turn off rebooting via CTL-ALT-DEL -- we get a
669 * SIGINT on CAD so we can shut things down gracefully... */
670 reboot(RB_DISABLE_CAD);
673 /* Figure out where the default console should be */
676 /* Close whatever files are open, and reset the console. */
682 /* Make sure PATH is set to something sane */
683 putenv(_PATH_STDPATH);
689 "init started: BusyBox v%s (%s) multi-call binary\r\n",
693 "init(%d) started: BusyBox v%s (%s) multi-call binary\r\n",
694 getpid(), BB_VER, BB_BT);
699 if (mount ("proc", "/proc", "proc", 0, 0) == 0) {
700 message(LOG|CONSOLE, "Mounting /proc: done.\n");
701 kernel_version = get_kernel_revision();
703 message(LOG|CONSOLE, "Mounting /proc: failed!\n");
705 /* Make sure there is enough memory to do something useful. */
708 /* Check if we are supposed to be in single user mode */
709 if ( argc > 1 && (!strcmp(argv[1], "single") ||
710 !strcmp(argv[1], "-s") || !strcmp(argv[1], "1")))
712 /* Ask first then start a shell on tty2 */
713 if (second_console != NULL)
714 new_initAction( ASKFIRST, SHELL, second_console);
715 /* Ask first then start a shell on tty1 */
716 new_initAction( ASKFIRST, SHELL, console);
718 /* Not in single user mode -- see what inittab says */
720 /* NOTE that if BB_FEATURE_USE_INITTAB is NOT defined,
721 * then parse_inittab() simply adds in some default
722 * actions(i.e runs INIT_SCRIPT and then starts a pair
723 * of "askfirst" shells */
727 /* Now run everything that needs to be run */
729 message(LOG|CONSOLE, "Running SYSINIT\n");
730 /* First run the sysinit command */
731 for( a=initActionList ; a; a=a->nextPtr) {
732 if (a->action == SYSINIT) {
733 waitfor(a->process, a->console, FALSE);
734 /* Now remove the "sysinit" entry from the list */
735 delete_initAction( a);
738 /* Next run anything that wants to block */
739 for( a=initActionList ; a; a=a->nextPtr) {
740 if (a->action == WAIT) {
741 waitfor(a->process, a->console, FALSE);
742 /* Now remove the "wait" entry from the list */
743 delete_initAction( a);
746 /* Next run anything to be run only once */
747 for( a=initActionList ; a; a=a->nextPtr) {
748 if (a->action == ONCE) {
749 run(a->process, a->console, FALSE);
750 /* Now remove the "once" entry from the list */
751 delete_initAction( a);
754 /* If there is nothing else to do, stop */
755 if (initActionList == NULL) {
756 message(LOG|CONSOLE, "No more tasks for init -- sleeping forever.\n");
760 /* Now run the looping stuff for the rest of forever */
762 for( a=initActionList ; a; a=a->nextPtr) {
763 /* Only run stuff with pid==0. If they have
764 * a pid, that means they are still running */
768 /* run the respawn stuff */
769 a->pid = run(a->process, a->console, FALSE);
772 /* run the askfirst stuff */
773 a->pid = run(a->process, a->console, TRUE);
775 /* silence the compiler's incessant whining */
781 /* Wait for a child process to exit */
782 wpid = wait(&status);
784 /* Find out who died and clean up their corpse */
785 for( a=initActionList ; a; a=a->nextPtr) {
788 message(LOG, "Process '%s' (pid %d) exited. Scheduling it for restart.\n",