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 "-sh" /* Default shell */
65 #define INITTAB "/etc/inittab" /* inittab file location */
66 #define INIT_SCRIPT "/etc/init.d/rcS" /* Default sysinit script. */
71 /* Allowed init action types */
80 /* And now a list of the actions we support in the version of init */
81 typedef struct initActionType{
83 initActionEnum action;
86 static const struct initActionType actions[] = {
89 {"askfirst", ASKFIRST},
95 /* Set up a linked list of initactions, to be read from inittab */
96 typedef struct initActionTag initAction;
97 struct initActionTag {
102 initActionEnum action;
104 initAction* initActionList = NULL;
107 static char *console = _PATH_CONSOLE;
108 static char *second_console = VT_SECONDARY;
109 static char *log = VT_LOG;
110 static int kernel_version = 0;
113 /* try to open up the specified device */
114 int device_open(char *device, int mode)
118 m = mode | O_NONBLOCK;
120 /* Retry up to 5 times */
121 for (f = 0; f < 5; f++)
122 if ((fd = open(device, m)) >= 0)
126 /* Reset original flags. */
128 fcntl(fd, F_SETFL, mode);
132 /* print a message to the specified device:
133 * device may be bitwise-or'd from LOG | CONSOLE */
134 void message(int device, char *fmt, ...)
141 /* Log the message to syslogd */
144 va_start(arguments, fmt);
145 vsnprintf(msg, sizeof(msg), fmt, arguments);
147 syslog(LOG_DAEMON|LOG_NOTICE, msg);
151 static int log_fd=-1;
153 /* Take full control of the log tty, and never close it.
154 * It's mine, all mine! Muhahahaha! */
157 /* don't even try to log, because there is no such console */
159 /* log to main console instead */
162 else if ((log_fd = device_open(log, O_RDWR|O_NDELAY)) < 0) {
164 fprintf(stderr, "Bummer, can't write to log on %s!\r\n", log);
169 if ( (device & LOG) && (log_fd >= 0) ) {
170 va_start(arguments, fmt);
171 vdprintf(log_fd, fmt, arguments);
176 if (device & CONSOLE) {
177 /* Always send console messages to /dev/console so people will see them. */
178 if ((fd = device_open(_PATH_CONSOLE, O_WRONLY|O_NOCTTY|O_NDELAY)) >= 0) {
179 va_start(arguments, fmt);
180 vdprintf(fd, fmt, arguments);
184 fprintf(stderr, "Bummer, can't print: ");
185 va_start(arguments, fmt);
186 vfprintf(stderr, fmt, arguments);
194 /* Set terminal settings to reasonable defaults */
195 void set_term( int fd)
198 static const char control_characters[] = {
199 '\003', '\034', '\177', '\025', '\004', '\0',
200 '\1', '\0', '\021', '\023', '\032', '\0', '\022',
201 '\017', '\027', '\026', '\0'
206 /* set control chars */
207 memcpy(tty.c_cc, control_characters, sizeof(control_characters));
209 /* use line dicipline 0 */
212 /* Make it be sane */
213 //tty.c_cflag &= CBAUD|CBAUDEX|CSIZE|CSTOPB|PARENB|PARODD;
214 //tty.c_cflag |= HUPCL|CLOCAL;
217 tty.c_iflag = ICRNL|IXON|IXOFF;
220 tty.c_oflag = OPOST|ONLCR;
223 tty.c_lflag = ISIG|ICANON|ECHO|ECHOE|ECHOK|ECHOCTL|ECHOKE|IEXTEN;
225 tcsetattr(fd, TCSANOW, &tty);
228 /* How much memory does this machine have? */
229 static int mem_total()
232 char *p = "/proc/meminfo";
234 const char pattern[] = "MemTotal:";
236 if ((f = fopen(p, "r")) < 0) {
237 message(LOG, "Error opening %s: %s\n", p, strerror( errno));
240 while (NULL != fgets(s, 79, f)) {
241 p = strstr(s, pattern);
244 return (atoi(p + strlen(pattern)));
250 static void console_init()
253 int tried_devcons = 0;
254 int tried_vtprimary = 0;
255 struct serial_struct sr;
258 if ((s = getenv("CONSOLE")) != NULL) {
262 /* sparc kernel supports console=tty[ab] parameter which is also
263 * passed to init, so catch it here */
264 else if ((s = getenv("console")) != NULL) {
265 /* remap tty[ab] to /dev/ttyS[01] */
266 if (strcmp( s, "ttya" )==0)
267 console = SERIAL_CON0;
268 else if (strcmp( s, "ttyb" )==0)
269 console = SERIAL_CON1;
274 static char the_console[13];
276 console = the_console;
277 /* 2.2 kernels: identify the real console backend and try to use it */
278 if (ioctl(0, TIOCGSERIAL, &sr) == 0) {
279 /* this is a serial console */
280 snprintf( the_console, sizeof the_console, "/dev/ttyS%d", sr.line );
282 else if (ioctl(0, VT_GETSTATE, &vt) == 0) {
283 /* this is linux virtual tty */
284 snprintf( the_console, sizeof the_console, "/dev/tty%d", vt.v_active );
286 console = _PATH_CONSOLE;
291 while ((fd = open(console, O_RDONLY | O_NONBLOCK)) < 0) {
292 /* Can't open selected console -- try /dev/console */
293 if (!tried_devcons) {
295 console = _PATH_CONSOLE;
298 /* Can't open selected console -- try vt1 */
299 if (!tried_vtprimary) {
301 console = VT_PRIMARY;
307 /* Perhaps we should panic here? */
308 console = "/dev/null";
310 /* check for serial console and disable logging to tty3 & running a
312 if (ioctl(0,TIOCGSERIAL,&sr) == 0) {
313 message(LOG|CONSOLE, "serial console detected. Disabling 2nd virtual terminal.\r\n", console );
315 second_console = NULL;
319 message(LOG, "console=%s\n", console );
322 static int waitfor(int pid)
327 wpid = wait(&status);
329 message(LOG, "pid %d exited, status=0x%x.\n", wpid, status);
338 static pid_t run(char* command,
339 char *terminal, int get_enter)
345 static const char press_enter[] =
346 "\nPlease press Enter to activate this console. ";
348 if ((pid = fork()) == 0) {
349 pid_t shell_pgid = getpid ();
357 if (device_open(terminal, O_RDWR) < 0) {
358 message(LOG|CONSOLE, "Bummer, can't open %s\r\n", terminal);
363 /* Grab control of the terminal. */
364 if (tcsetpgrp (0, getpgrp()) < 0) {
365 message(LOG|CONSOLE, "tcsetpgrp error: %s\r\n", strerror(errno));
369 /* Reset signal handlers set for parent process */
370 signal(SIGUSR1, SIG_DFL);
371 signal(SIGUSR2, SIG_DFL);
372 signal(SIGINT, SIG_DFL);
373 signal(SIGTERM, SIG_DFL);
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
386 message(LOG, "Waiting for enter to start '%s' (pid %d, console %s)\r\n",
387 command, shell_pgid, terminal );
388 write(fileno(stdout), press_enter, sizeof(press_enter) - 1);
389 read(fileno(stdin), &c, 1);
392 /* Convert command (char*) into cmd (char**, one word per string) */
393 for (tmpCmd=command, i=0; (tmpCmd=strsep(&command, " \t")) != NULL;) {
394 if (*tmpCmd != '\0') {
402 /* Log the process name and args */
403 message(LOG, "Starting pid %d, console %s: '%s'\r\n",
404 shell_pgid, terminal, cmd[0]);
406 /* Now run it. The new program will take over this PID,
407 * so nothing further in init.c should be run. */
410 /* We're still here? Some error happened. */
411 message(LOG|CONSOLE, "Bummer, could not run '%s': %s\n", cmd[0],
418 /* Make sure there is enough memory to do something useful. *
419 * Calls swapon if needed so be sure /proc is mounted. */
420 static void check_memory()
424 if (mem_total() > 3500)
427 if (stat("/etc/fstab", &statbuf) == 0) {
428 /* Try to turn on swap */
429 waitfor(run("/bin/swapon swapon -a", log, FALSE));
430 if (mem_total() < 3500)
437 message(CONSOLE, "Sorry, your computer does not have enough memory.\r\n");
442 static void shutdown_system(void)
444 /* Allow Ctrl-Alt-Del to reboot system. */
445 reboot(RB_ENABLE_CAD);
446 message(CONSOLE, "\r\nThe system is going down NOW !!\r\n");
449 /* Send signals to every process _except_ pid 1 */
450 message(CONSOLE, "Sending SIGHUP to all processes.\r\n");
455 message(CONSOLE, "Sending SIGKILL to all processes.\r\n");
459 message(CONSOLE, "Disabling swap.\r\n");
460 waitfor(run( "swapoff -a", console, FALSE));
461 message(CONSOLE, "Unmounting filesystems.\r\n");
462 waitfor(run( "umount -a", console, FALSE));
464 if (kernel_version > 0 && kernel_version <= 2 * 65536 + 2 * 256 + 11) {
465 /* bdflush, kupdate not needed for kernels >2.2.11 */
466 message(CONSOLE, "Flushing buffers.\r\n");
472 static void halt_signal(int sig)
476 "The system is halted. Press CTRL-ALT-DEL or turn off power\r\n");
478 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,2,0)
480 reboot(RB_POWER_OFF);
483 reboot(RB_HALT_SYSTEM);
487 static void reboot_signal(int sig)
490 message(CONSOLE, "Please stand by while rebooting the system.\r\n");
498 void new_initAction (const struct initActionType *a,
499 char* process, char* console)
501 initAction* newAction;
502 newAction = calloc ((size_t)(1), sizeof(initAction));
504 fprintf(stderr, "Memory allocation failure\n");
507 newAction->nextPtr = initActionList;
508 initActionList = newAction;
509 strncpy( newAction->process, process, 255);
510 newAction->action = a->action;
511 newAction->console = console;
515 void delete_initAction (initAction *action)
517 initAction *a, *b=NULL;
518 for( a=initActionList ; a; b=a, a=a->nextPtr) {
519 if (a == action && b != NULL) {
520 b->nextPtr=a->nextPtr;
527 void parse_inittab(void)
532 const struct initActionType *a = actions;
536 file = fopen(INITTAB, "r");
538 /* No inittab file -- set up some default behavior */
540 /* Askfirst shell on tty1 */
541 new_initAction( &(actions[3]), SHELL, console );
542 /* Askfirst shell on tty2 */
543 if (second_console != NULL)
544 new_initAction( &(actions[3]), SHELL, second_console );
546 new_initAction( &(actions[0]), INIT_SCRIPT, console );
551 while ( fgets(buf, 255, file) != NULL) {
553 for(p = buf; *p == ' ' || *p == '\t'; p++);
554 if (*p == '#' || *p == '\n') continue;
556 /* Trim the trailing \n */
557 q = strrchr( p, '\n');
561 /* Skip past the ID field and the runlevel
562 * field (both are ignored) */
565 /* Now peal off the process field from the end
567 q = strrchr( p, ':');
568 if ( q == NULL || *(q+1) == '\0' ) {
569 fprintf(stderr, "Bad inittab entry: %s\n", buf);
576 /* Now peal off the action field */
577 r = strrchr( p, ':');
578 if ( r == NULL || *(r+1) == '\0') {
579 fprintf(stderr, "Bad inittab entry: %s\n", buf);
585 /* Ok, now process it */
587 while (a->name != 0) {
588 if (strcmp(a->name, r) == 0) {
589 new_initAction( a, q, NULL);
597 /* Choke on an unknown action */
598 fprintf(stderr, "Bad inittab entry: %s\n", buf);
605 extern int init_main(int argc, char **argv)
612 /* Expect to be PID 1 iff we are run as init (not linuxrc) */
613 if (getpid() != 1 && strstr(argv[0], "init")!=NULL ) {
614 usage( "init\n\nInit is the parent of all processes.\n\n"
615 "This version of init is designed to be run only by the kernel\n");
618 /* from the controlling terminal */
621 /* Set up sig handlers -- be sure to clear all of these in run() */
622 signal(SIGUSR1, halt_signal);
623 signal(SIGUSR2, reboot_signal);
624 signal(SIGINT, reboot_signal);
625 signal(SIGTERM, reboot_signal);
627 /* Turn off rebooting via CTL-ALT-DEL -- we get a
628 * SIGINT on CAD so we can shut things down gracefully... */
629 reboot(RB_DISABLE_CAD);
632 /* Figure out where the default console should be */
635 /* Close whatever files are open, and reset the console. */
641 /* Make sure PATH is set to something sane */
642 putenv(_PATH_STDPATH);
648 "init started: BusyBox v%s (%s) multi-call binary\r\n",
652 "init(%d) started: BusyBox v%s (%s) multi-call binary\r\n",
653 getpid(), BB_VER, BB_BT);
658 if (mount ("proc", "/proc", "proc", 0, 0) == 0) {
659 message(CONSOLE|LOG, "Mounting /proc: done.\n");
660 kernel_version = get_kernel_revision();
662 message(CONSOLE|LOG, "Mounting /proc: failed!\n");
664 /* Make sure there is enough memory to do something useful. */
667 /* Check if we are supposed to be in single user mode */
668 if ( argc > 1 && (!strcmp(argv[1], "single") ||
669 !strcmp(argv[1], "-s") || !strcmp(argv[1], "1")))
671 /* Ask first then start a shell on tty2 */
672 if (second_console != NULL)
673 new_initAction( &(actions[3]), SHELL, second_console);
674 /* Ask first then start a shell on tty1 */
675 new_initAction( &(actions[3]), SHELL, console);
677 /* Not in single user mode -- see what inittab says */
681 /* Now run everything that needs to be run */
683 /* First run the sysinit command */
684 for( a=initActionList ; a; a=a->nextPtr) {
685 if (a->action == SYSINIT) {
686 waitfor(run(a->process, console, FALSE));
687 /* Now remove the "sysinit" entry from the list */
688 delete_initAction( a);
691 /* Next run anything that wants to block */
692 for( a=initActionList ; a; a=a->nextPtr) {
693 if (a->action == WAIT) {
694 waitfor(run(a->process, console, FALSE));
695 /* Now remove the "wait" entry from the list */
696 delete_initAction( a);
699 /* Next run anything to be run only once */
700 for( a=initActionList ; a; a=a->nextPtr) {
701 if (a->action == ONCE) {
702 run(a->process, console, FALSE);
703 /* Now remove the "once" entry from the list */
704 delete_initAction( a);
708 /* Now run the looping stuff for the rest of forever */
710 for( a=initActionList ; a; a=a->nextPtr) {
711 /* Only run stuff with pid==0. If they have
712 * a pid, that means they are still running */
716 /* run the respawn stuff */
717 a->pid = run(a->process, console, FALSE);
720 /* run the askfirst stuff */
721 a->pid = run(a->process, console, TRUE);
723 /* silence the compiler's incessant whining */
729 /* Wait for a child process to exit */
730 wpid = wait(&status);
732 /* Find out who died and clean up their corpse */
733 for( a=initActionList ; a; a=a->nextPtr) {
736 message(LOG, "Process '%s' (pid %d) exited. Scheduling it for restart.\n",