init/init.c - codeaurora/busybox - Gitiles

 /*
  * Mini init implementation for busybox
  *
  *
  * Copyright (C) 1995, 1996 by Bruce Perens <bruce@pixar.com>.
  * Adjusted by so many folks, it's impossible to keep track.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation; either version 2 of the License, or
  * (at your option) any later version.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  * General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with this program; if not, write to the Free Software
  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  *
  */

 #include "internal.h"
 #include <stdio.h>
 #include <string.h>
 #include <stdlib.h>
 #include <stdarg.h>
 #include <unistd.h>
 #include <errno.h>
 #include <signal.h>
 #include <termios.h>
 #include <paths.h>
 #include <sys/types.h>
 #include <sys/fcntl.h>
 #include <sys/wait.h>
 #include <string.h>
 #include <sys/mount.h>
 #include <sys/reboot.h>
 #include <sys/kdaemon.h>
 #include <sys/sysmacros.h>
 #include <linux/serial.h>	/* for serial_struct */
 #include <sys/vt.h>		/* for vt_stat */
 #include <sys/ioctl.h>
 #include <linux/version.h>
 #ifdef BB_SYSLOGD
 #include <sys/syslog.h>
 #endif

 #if ! defined BB_FEATURE_USE_PROCFS
 #error Sorry, I depend on the /proc filesystem right now.
 #endif

 #ifndef KERNEL_VERSION
 #define KERNEL_VERSION(a,b,c) (((a) << 16) + ((b) << 8) + (c))
 #endif


 #define VT_PRIMARY      "/dev/tty1"	  /* Primary virtual console */
 #define VT_SECONDARY    "/dev/tty2"	  /* Virtual console */
 #define VT_LOG          "/dev/tty3"	  /* Virtual console */
 #define SERIAL_CON0     "/dev/ttyS0"      /* Primary serial console */
 #define SERIAL_CON1     "/dev/ttyS1"      /* Serial console */
 #define SHELL           "-sh"		  /* Default shell */
 #define INITTAB         "/etc/inittab"	  /* inittab file location */
 #define INIT_SCRIPT	"/etc/init.d/rcS" /* Default sysinit script. */

 #define LOG             0x1
 #define CONSOLE         0x2

 /* Allowed init action types */
 typedef enum {
     SYSINIT=1,
     RESPAWN,
     ASKFIRST,
     WAIT,
     ONCE
 } initActionEnum;

 /* And now a list of the actions we support in the version of init */
 typedef struct initActionType{
     const char*	name;
     initActionEnum action;
 } initActionType;

 static const struct initActionType actions[] = {
     {"sysinit",     SYSINIT},
     {"respawn",     RESPAWN},
     {"askfirst",    ASKFIRST},
     {"wait",        WAIT},
     {"once",        ONCE},
     {0}
 };

 /* Set up a linked list of initactions, to be read from inittab */
 typedef struct initActionTag initAction;
 struct initActionTag {
     pid_t pid;
     char process[256];
     char console[256];
     initAction *nextPtr;
     initActionEnum action;
 };
 initAction* initActionList = NULL;


 static char *console = _PATH_CONSOLE;
 static char *second_console = VT_SECONDARY;
 static char *log = VT_LOG;
 static int kernel_version = 0;


 /* try to open up the specified device */
 int device_open(char *device, int mode)
 {
     int m, f, fd = -1;

     m = mode | O_NONBLOCK;

     /* Retry up to 5 times */
     for (f = 0; f < 5; f++)
 	if ((fd = open(device, m)) >= 0)
 	    break;
     if (fd < 0)
 	return fd;
     /* Reset original flags. */
     if (m != mode)
 	fcntl(fd, F_SETFL, mode);
     return fd;
 }

 /* print a message to the specified device:
  * device may be bitwise-or'd from LOG | CONSOLE */
 void message(int device, char *fmt, ...)
 {
     va_list arguments;
     int fd;

 #ifdef BB_SYSLOGD

     /* Log the message to syslogd */
     if (device & LOG ) {
 	char msg[1024];
 	va_start(arguments, fmt);
 	vsnprintf(msg, sizeof(msg), fmt, arguments);
 	va_end(arguments);
 	syslog(LOG_DAEMON|LOG_NOTICE, msg);
     }

 #else
     static int log_fd=-1;

     /* Take full control of the log tty, and never close it.
      * It's mine, all mine!  Muhahahaha! */
     if (log_fd < 0) {
 	if (log == NULL) {
 	/* don't even try to log, because there is no such console */
 	log_fd = -2;
 	/* log to main console instead */
 	device = CONSOLE;
     }
     else if ((log_fd = device_open(log, O_RDWR|O_NDELAY)) < 0) {
 	    log_fd=-1;
 	    fprintf(stderr, "Bummer, can't write to log on %s!\r\n", log);
 	    fflush(stderr);
 	    return;
 	}
     }
     if ( (device & LOG) && (log_fd >= 0) ) {
 	va_start(arguments, fmt);
 	vdprintf(log_fd, fmt, arguments);
 	va_end(arguments);
     }
 #endif

     if (device & CONSOLE) {
 	/* Always send console messages to /dev/console so people will see them. */
 	if ((fd = device_open(_PATH_CONSOLE, O_WRONLY|O_NOCTTY|O_NDELAY)) >= 0) {
 	    va_start(arguments, fmt);
 	    vdprintf(fd, fmt, arguments);
 	    va_end(arguments);
 	    close(fd);
 	} else {
 	    fprintf(stderr, "Bummer, can't print: ");
 	    va_start(arguments, fmt);
 	    vfprintf(stderr, fmt, arguments);
 	    fflush(stderr);
 	    va_end(arguments);
 	}
     }
 }


 /* Set terminal settings to reasonable defaults */
 void set_term( int fd)
 {
     struct termios tty;
     static const char control_characters[] = {
 	'\003', '\034', '\177', '\025', '\004', '\0',
 	'\1', '\0', '\021', '\023', '\032', '\0', '\022',
 	'\017', '\027', '\026', '\0'
 	};

     tcgetattr(fd, &tty);

     /* set control chars */
     memcpy(tty.c_cc, control_characters, sizeof(control_characters));

     /* use line dicipline 0 */
     tty.c_line = 0;

     /* Make it be sane */
     //tty.c_cflag &= CBAUD|CBAUDEX|CSIZE|CSTOPB|PARENB|PARODD;
     //tty.c_cflag |= HUPCL|CLOCAL;

     /* input modes */
     tty.c_iflag = ICRNL|IXON|IXOFF;

     /* output modes */
     tty.c_oflag = OPOST|ONLCR;

     /* local modes */
     tty.c_lflag = ISIG|ICANON|ECHO|ECHOE|ECHOK|ECHOCTL|ECHOKE|IEXTEN;

     tcsetattr(fd, TCSANOW, &tty);
 }

 /* How much memory does this machine have? */
 static int mem_total()
 {
     char s[80];
     char *p = "/proc/meminfo";
     FILE *f;
     const char pattern[] = "MemTotal:";

     if ((f = fopen(p, "r")) < 0) {
 	message(LOG, "Error opening %s: %s\n", p, strerror( errno));
 	return -1;
     }
     while (NULL != fgets(s, 79, f)) {
 	p = strstr(s, pattern);
 	if (NULL != p) {
 	    fclose(f);
 	    return (atoi(p + strlen(pattern)));
 	}
     }
     return -1;
 }

 static void console_init()
 {
     int fd;
     int tried_devcons = 0;
     int tried_vtprimary = 0;
     struct serial_struct sr;
     char *s;

     if ((s = getenv("CONSOLE")) != NULL) {
 	console = s;
     }
 #if #cpu(sparc)
     /* sparc kernel supports console=tty[ab] parameter which is also
      * passed to init, so catch it here */
     else if ((s = getenv("console")) != NULL) {
 	/* remap tty[ab] to /dev/ttyS[01] */
 	if (strcmp( s, "ttya" )==0)
 	    console = SERIAL_CON0;
 	else if (strcmp( s, "ttyb" )==0)
 	    console = SERIAL_CON1;
     }
 #endif
     else {
 	struct vt_stat vt;
 	static char the_console[13];

 	console = the_console;
 	/* 2.2 kernels: identify the real console backend and try to use it */
 	if (ioctl(0, TIOCGSERIAL, &sr) == 0) {
 	    /* this is a serial console */
 	    snprintf( the_console, sizeof the_console, "/dev/ttyS%d", sr.line );
 	}
 	else if (ioctl(0, VT_GETSTATE, &vt) == 0) {
 	    /* this is linux virtual tty */
 	    snprintf( the_console, sizeof the_console, "/dev/tty%d", vt.v_active );
 	} else {
 	    console = _PATH_CONSOLE;
 	    tried_devcons++;
 	}
     }

     while ((fd = open(console, O_RDONLY | O_NONBLOCK)) < 0) {
 	/* Can't open selected console -- try /dev/console */
 	if (!tried_devcons) {
 	    tried_devcons++;
 	    console = _PATH_CONSOLE;
 	    continue;
 	}
 	/* Can't open selected console -- try vt1 */
 	if (!tried_vtprimary) {
 	    tried_vtprimary++;
 	    console = VT_PRIMARY;
 	    continue;
 	}
 	break;
     }
     if (fd < 0)
 	/* Perhaps we should panic here? */
 	console = "/dev/null";
     else {
 	/* check for serial console and disable logging to tty3 & running a
 	* shell to tty2 */
 	if (ioctl(0,TIOCGSERIAL,&sr) == 0) {
 	    message(LOG|CONSOLE, "serial console detected.  Disabling 2nd virtual terminal.\r\n", console );
 	    log = NULL;
 	    second_console = NULL;
 	}
 	close(fd);
     }
     message(LOG, "console=%s\n", console );
 }

 static int waitfor(int pid)
 {
     int status, wpid;

     while (1) {
 	wpid = wait(&status);
 	if (wpid > 0 ) {
 	    message(LOG, "pid %d exited, status=0x%x.\n", wpid, status);
 	    break;
 	}
 	if (wpid == pid )
 	    break;
     }
     return wpid;
 }

 static pid_t run(char* command,
 	char *terminal, int get_enter)
 {
     int i;
     pid_t pid;
     char* tmpCmd;
     char* cmd[255];
     static const char press_enter[] =
 	"\nPlease press Enter to activate this console. ";

     if ((pid = fork()) == 0) {
 	pid_t shell_pgid = getpid ();

 	/* Clean up */
 	close(0);
 	close(1);
 	close(2);
 	setsid();

 	if (device_open(terminal, O_RDWR) < 0) {
 	    message(LOG|CONSOLE, "Bummer, can't open %s\r\n", terminal);
 	    exit(1);
 	}
 	dup(0);
 	dup(0);
 	/* Grab control of the terminal.  */
 	if (tcsetpgrp (0, getpgrp()) < 0) {
 	    message(LOG|CONSOLE, "tcsetpgrp error: %s\r\n", strerror(errno));
 	}
 	set_term(0);

 	/* Reset signal handlers set for parent process */
 	signal(SIGUSR1, SIG_DFL);
 	signal(SIGUSR2, SIG_DFL);
 	signal(SIGINT, SIG_DFL);
 	signal(SIGTERM, SIG_DFL);


 	if (get_enter==TRUE) {
 	    /*
 	     * Save memory by not exec-ing anything large (like a shell)
 	     * before the user wants it. This is critical if swap is not
 	     * enabled and the system has low memory. Generally this will
 	     * be run on the second virtual console, and the first will
 	     * be allowed to start a shell or whatever an init script
 	     * specifies.
 	     */
 	    char c;
 	    message(LOG, "Waiting for enter to start '%s' (pid %d, console %s)\r\n",
 		    command, shell_pgid, terminal );
 	    write(fileno(stdout), press_enter, sizeof(press_enter) - 1);
 	    read(fileno(stdin), &c, 1);
 	}

 	/* Convert command (char*) into cmd (char**, one word per string) */
 	for (tmpCmd=command, i=0; (tmpCmd=strsep(&command, " \t")) != NULL;) {
 	    if (*tmpCmd != '\0') {
 		cmd[i] = tmpCmd;
 		tmpCmd++;
 		i++;
 	    }
 	}
 	cmd[i] = NULL;

 	/* Log the process name and args */
 	message(LOG, "Starting pid %d, console %s: '%s'\r\n",
 		shell_pgid, terminal, cmd[0]);

 	/* Now run it.  The new program will take over this PID,
 	 * so nothing further in init.c should be run. */
 	execvp(cmd[0], cmd);

 	/* We're still here?  Some error happened. */
 	message(LOG|CONSOLE, "Bummer, could not run '%s': %s\n", cmd[0],
 		strerror(errno));
 	exit(-1);
     }
     return pid;
 }

 /* Make sure there is enough memory to do something useful. *
  * Calls swapon if needed so be sure /proc is mounted. */
 static void check_memory()
 {
     struct stat statbuf;

     if (mem_total() > 3500)
 	return;

     if (stat("/etc/fstab", &statbuf) == 0) {
 	/* Try to turn on swap */
 	waitfor(run("/bin/swapon swapon -a", log, FALSE));
 	if (mem_total() < 3500)
 	    goto goodnight;
     } else
 	goto goodnight;
     return;

 goodnight:
 	message(CONSOLE, "Sorry, your computer does not have enough memory.\r\n");
 	while (1) sleep(1);
 }

 #ifndef DEBUG_INIT
 static void shutdown_system(void)
 {
     /* Allow Ctrl-Alt-Del to reboot system. */
     reboot(RB_ENABLE_CAD);
     message(CONSOLE, "\r\nThe system is going down NOW !!\r\n");
     sync();

     /* Send signals to every process _except_ pid 1 */
     message(CONSOLE, "Sending SIGHUP to all processes.\r\n");
     kill(-1, SIGHUP);
     sleep(2);
     sync();

     message(CONSOLE, "Sending SIGKILL to all processes.\r\n");
     kill(-1, SIGKILL);
     sleep(1);

     message(CONSOLE, "Disabling swap.\r\n");
     waitfor(run( "swapoff -a", console, FALSE));
     message(CONSOLE, "Unmounting filesystems.\r\n");
     waitfor(run( "umount -a", console, FALSE));
     sync();
     if (kernel_version > 0 && kernel_version <= 2 * 65536 + 2 * 256 + 11) {
 	/* bdflush, kupdate not needed for kernels >2.2.11 */
 	message(CONSOLE, "Flushing buffers.\r\n");
 	bdflush(1, 0);
 	sync();
     }
 }

 static void halt_signal(int sig)
 {
     shutdown_system();
     message(CONSOLE,
 	    "The system is halted. Press CTRL-ALT-DEL or turn off power\r\n");
     sync();
 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,2,0)
     if (sig == SIGUSR2)
 	reboot(RB_POWER_OFF);
     else
 #endif
     reboot(RB_HALT_SYSTEM);
     exit(0);
 }

 static void reboot_signal(int sig)
 {
     shutdown_system();
     message(CONSOLE, "Please stand by while rebooting the system.\r\n");
     sync();
     reboot(RB_AUTOBOOT);
     exit(0);
 }

 #endif

 void new_initAction (const struct initActionType *a,
 	char* process, char* cons)
 {
     initAction* newAction;

     /* If BusyBox detects that a serial console is in use,
      * then entries containing non-empty id fields will _not_ be run.
      */
     if (second_console != NULL && *cons != '\0')
 	return;

     newAction = calloc ((size_t)(1), sizeof(initAction));
     if (!newAction) {
 	fprintf(stderr, "Memory allocation failure\n");
 	while (1) sleep(1);
     }
     newAction->nextPtr = initActionList;
     initActionList = newAction;
     strncpy( newAction->process, process, 255);
     newAction->action = a->action;
     if (*cons != '\0')
 	strncpy(newAction->console, cons, 255);
     else
 	strncpy(newAction->console, console, 255);
     newAction->pid = 0;
 }

 void delete_initAction (initAction *action)
 {
     initAction *a, *b=NULL;
     for( a=initActionList ; a; b=a, a=a->nextPtr) {
 	if (a == action && b != NULL) {
 	    b->nextPtr=a->nextPtr;
 	    free( a);
 	    break;
 	}
     }
 }

 /* NOTE that if BB_FEATURE_USE_INITTAB is NOT defined,
  * then parse_inittab() simply adds in some default
  * actions(i.e runs INIT_SCRIPT and then starts a pair
  * of "askfirst" shells.  If BB_FEATURE_USE_INITTAB
  * _is_ defined, but /etc/inittab is missing == same
  * default behavior.
  * */
 void parse_inittab(void)
 {
 #ifdef BB_FEATURE_USE_INITTAB
     FILE* file;
     char buf[256], buf1[256];
     char *p, *q, *r, *s;
     const struct initActionType *a = actions;
     int foundIt;


     file = fopen(INITTAB, "r");
     if (file == NULL) {
 	/* No inittab file -- set up some default behavior */
 #endif
 	/* Askfirst shell on tty1 */
 	new_initAction( &(actions[3]), SHELL, console );
 	/* Askfirst shell on tty2 */
 	if (second_console != NULL)
 	    new_initAction( &(actions[3]), SHELL, second_console );
 	/* sysinit */
 	new_initAction( &(actions[0]), INIT_SCRIPT, console );

 	return;
 #ifdef BB_FEATURE_USE_INITTAB
     }

     while ( fgets(buf, 255, file) != NULL) {
 	foundIt=FALSE;
 	for(p = buf; *p == ' ' || *p == '\t'; p++);
 	if (*p == '#' || *p == '\n') continue;

 	/* Trim the trailing \n */
 	q = strrchr( p, '\n');
 	if (q != NULL)
 	    *q='\0';

 	/* Keep a copy around for posterity's sake (and error msgs) */
 	strcpy(buf1, buf);

 	/* Grab the ID field */
 	s=p;
 	p = strchr( p, ':');
 	if ( p != NULL || *(p+1) != '\0' ) {
 	    *p='\0';
 	    ++p;
 	}

 	/* Now peal off the process field from the end
 	 * of the string */
 	q = strrchr( p, ':');
 	if ( q == NULL || *(q+1) == '\0' ) {
 	    fprintf(stderr, "Bad inittab entry: %s\n", buf1);
 	    continue;
 	} else {
 	    *q='\0';
 	    ++q;
 	}

 	/* Now peal off the action field */
 	r = strrchr( p, ':');
 	if ( r == NULL || *(r+1) == '\0') {
 	    fprintf(stderr, "Bad inittab entry: %s\n", buf1);
 	    continue;
 	} else {
 	    ++r;
 	}

 	/* Ok, now process it */
 	a = actions;
 	while (a->name != 0) {
 	    if (strcmp(a->name, r) == 0) {
 		new_initAction( a, q, s);
 		foundIt=TRUE;
 	    }
 	    a++;
 	}
 	if (foundIt==TRUE)
 	    continue;
 	else {
 	    /* Choke on an unknown action */
 	    fprintf(stderr, "Bad inittab entry: %s\n", buf1);
 	}
     }
     return;
 #endif
 }

 extern int init_main(int argc, char **argv)
 {
     initAction *a;
     pid_t wpid;
     int status;

 #ifndef DEBUG_INIT
     /* Expect to be PID 1 iff we are run as init (not linuxrc) */
     if (getpid() != 1 && strstr(argv[0], "init")!=NULL ) {
 	usage( "init\n\nInit is the parent of all processes.\n\n"
 		"This version of init is designed to be run only by the kernel\n");
     }

     /* from the controlling terminal */
     setsid();

     /* Set up sig handlers  -- be sure to clear all of these in run() */
     signal(SIGUSR1, halt_signal);
     signal(SIGUSR2, reboot_signal);
     signal(SIGINT, reboot_signal);
     signal(SIGTERM, reboot_signal);

     /* Turn off rebooting via CTL-ALT-DEL -- we get a
      * SIGINT on CAD so we can shut things down gracefully... */
     reboot(RB_DISABLE_CAD);
 #endif

     /* Figure out where the default console should be */
     console_init();

     /* Close whatever files are open, and reset the console. */
     close(0);
     close(1);
     close(2);
     set_term(0);

     /* Make sure PATH is set to something sane */
     putenv(_PATH_STDPATH);


     /* Hello world */
 #ifndef DEBUG_INIT
     message(CONSOLE|LOG,
 	    "init started:  BusyBox v%s (%s) multi-call binary\r\n",
 	    BB_VER, BB_BT);
 #else
     message(CONSOLE|LOG,
 	    "init(%d) started:  BusyBox v%s (%s) multi-call binary\r\n",
 	    getpid(), BB_VER, BB_BT);
 #endif


     /* Mount /proc */
     if (mount ("proc", "/proc", "proc", 0, 0) == 0) {
 	message(CONSOLE|LOG, "Mounting /proc: done.\n");
 	kernel_version = get_kernel_revision();
     } else
 	message(CONSOLE|LOG, "Mounting /proc: failed!\n");

     /* Make sure there is enough memory to do something useful. */
     check_memory();

     /* Check if we are supposed to be in single user mode */
     if ( argc > 1 && (!strcmp(argv[1], "single") ||
 		!strcmp(argv[1], "-s") || !strcmp(argv[1], "1")))
     {
 	/* Ask first then start a shell on tty2 */
 	if (second_console != NULL)
 	    new_initAction( &(actions[3]), SHELL, second_console);
 	/* Ask first then start a shell on tty1 */
 	new_initAction( &(actions[3]), SHELL, console);
     } else {
 	/* Not in single user mode -- see what inittab says */

 	/* NOTE that if BB_FEATURE_USE_INITTAB is NOT defined,
 	 * then parse_inittab() simply adds in some default
 	 * actions(i.e runs INIT_SCRIPT and then starts a pair
 	 * of "askfirst" shells */
 	parse_inittab();
     }

     /* Now run everything that needs to be run */

     /* First run the sysinit command */
     for( a=initActionList ; a; a=a->nextPtr) {
 	if (a->action == SYSINIT) {
 	    waitfor(run(a->process, console, FALSE));
 	    /* Now remove the "sysinit" entry from the list */
 	    delete_initAction( a);
 	}
     }
     /* Next run anything that wants to block */
     for( a=initActionList ; a; a=a->nextPtr) {
 	if (a->action == WAIT) {
 	    waitfor(run(a->process, console, FALSE));
 	    /* Now remove the "wait" entry from the list */
 	    delete_initAction( a);
 	}
     }
     /* Next run anything to be run only once */
     for( a=initActionList ; a; a=a->nextPtr) {
 	if (a->action == ONCE) {
 	    run(a->process, console, FALSE);
 	    /* Now remove the "once" entry from the list */
 	    delete_initAction( a);
 	}
     }

     /* Now run the looping stuff for the rest of forever */
     while (1) {
 	for( a=initActionList ; a; a=a->nextPtr) {
 	    /* Only run stuff with pid==0.  If they have
 	     * a pid, that means they are still running */
 	    if (a->pid == 0) {
 		switch(a->action) {
 		    case RESPAWN:
 			/* run the respawn stuff */
 			a->pid = run(a->process, console, FALSE);
 			break;
 		    case ASKFIRST:
 			/* run the askfirst stuff */
 			a->pid = run(a->process, console, TRUE);
 			break;
 		    /* silence the compiler's incessant whining */
 		    default:
 			break;
 		}
 	    }
 	}
 	/* Wait for a child process to exit */
 	wpid = wait(&status);
 	if (wpid > 0 ) {
 	    /* Find out who died and clean up their corpse */
 	    for( a=initActionList ; a; a=a->nextPtr) {
 		if (a->pid==wpid) {
 		    a->pid=0;
 		    message(LOG, "Process '%s' (pid %d) exited.  Scheduling it for restart.\n",
 			    a->process, wpid);
 		}
 	    }
 	}
 	sleep(1);
     }
 }
	/*
	* Mini init implementation for busybox
	*
	*
	* Copyright (C) 1995, 1996 by Bruce Perens <bruce@pixar.com>.
	* Adjusted by so many folks, it's impossible to keep track.
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License as published by
	* the Free Software Foundation; either version 2 of the License, or
	* (at your option) any later version.
	*
	* This program is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	* General Public License for more details.
	*
	* You should have received a copy of the GNU General Public License
	* along with this program; if not, write to the Free Software
	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	*
	*/

	#include "internal.h"
	#include <stdio.h>
	#include <string.h>
	#include <stdlib.h>
	#include <stdarg.h>
	#include <unistd.h>
	#include <errno.h>
	#include <signal.h>
	#include <termios.h>
	#include <paths.h>
	#include <sys/types.h>
	#include <sys/fcntl.h>
	#include <sys/wait.h>
	#include <string.h>
	#include <sys/mount.h>
	#include <sys/reboot.h>
	#include <sys/kdaemon.h>
	#include <sys/sysmacros.h>
	#include <linux/serial.h> /* for serial_struct */
	#include <sys/vt.h> /* for vt_stat */
	#include <sys/ioctl.h>
	#include <linux/version.h>
	#ifdef BB_SYSLOGD
	#include <sys/syslog.h>
	#endif

	#if ! defined BB_FEATURE_USE_PROCFS
	#error Sorry, I depend on the /proc filesystem right now.
	#endif

	#ifndef KERNEL_VERSION
	#define KERNEL_VERSION(a,b,c) (((a) << 16) + ((b) << 8) + (c))
	#endif


	#define VT_PRIMARY "/dev/tty1" /* Primary virtual console */
	#define VT_SECONDARY "/dev/tty2" /* Virtual console */
	#define VT_LOG "/dev/tty3" /* Virtual console */
	#define SERIAL_CON0 "/dev/ttyS0" /* Primary serial console */
	#define SERIAL_CON1 "/dev/ttyS1" /* Serial console */
	#define SHELL "-sh" /* Default shell */
	#define INITTAB "/etc/inittab" /* inittab file location */
	#define INIT_SCRIPT "/etc/init.d/rcS" /* Default sysinit script. */

	#define LOG 0x1
	#define CONSOLE 0x2

	/* Allowed init action types */
	typedef enum {
	SYSINIT=1,
	RESPAWN,
	ASKFIRST,
	WAIT,
	ONCE
	} initActionEnum;

	/* And now a list of the actions we support in the version of init */
	typedef struct initActionType{
	const char* name;
	initActionEnum action;
	} initActionType;

	static const struct initActionType actions[] = {
	{"sysinit", SYSINIT},
	{"respawn", RESPAWN},
	{"askfirst", ASKFIRST},
	{"wait", WAIT},
	{"once", ONCE},
	{0}
	};

	/* Set up a linked list of initactions, to be read from inittab */
	typedef struct initActionTag initAction;
	struct initActionTag {
	pid_t pid;
	char process[256];
	char console[256];
	initAction *nextPtr;
	initActionEnum action;
	};
	initAction* initActionList = NULL;


	static char *console = _PATH_CONSOLE;
	static char *second_console = VT_SECONDARY;
	static char *log = VT_LOG;
	static int kernel_version = 0;


	/* try to open up the specified device */
	int device_open(char *device, int mode)
	{
	int m, f, fd = -1;

	m = mode \| O_NONBLOCK;

	/* Retry up to 5 times */
	for (f = 0; f < 5; f++)
	if ((fd = open(device, m)) >= 0)
	break;
	if (fd < 0)
	return fd;
	/* Reset original flags. */
	if (m != mode)
	fcntl(fd, F_SETFL, mode);
	return fd;
	}

	/* print a message to the specified device:
	* device may be bitwise-or'd from LOG \| CONSOLE */
	void message(int device, char *fmt, ...)
	{
	va_list arguments;
	int fd;

	#ifdef BB_SYSLOGD

	/* Log the message to syslogd */
	if (device & LOG ) {
	char msg[1024];
	va_start(arguments, fmt);
	vsnprintf(msg, sizeof(msg), fmt, arguments);
	va_end(arguments);
	syslog(LOG_DAEMON\|LOG_NOTICE, msg);
	}

	#else
	static int log_fd=-1;

	/* Take full control of the log tty, and never close it.
	* It's mine, all mine! Muhahahaha! */
	if (log_fd < 0) {
	if (log == NULL) {
	/* don't even try to log, because there is no such console */
	log_fd = -2;
	/* log to main console instead */
	device = CONSOLE;
	}
	else if ((log_fd = device_open(log, O_RDWR\|O_NDELAY)) < 0) {
	log_fd=-1;
	fprintf(stderr, "Bummer, can't write to log on %s!\r\n", log);
	fflush(stderr);
	return;
	}
	}
	if ( (device & LOG) && (log_fd >= 0) ) {
	va_start(arguments, fmt);
	vdprintf(log_fd, fmt, arguments);
	va_end(arguments);
	}
	#endif

	if (device & CONSOLE) {
	/* Always send console messages to /dev/console so people will see them. */
	if ((fd = device_open(_PATH_CONSOLE, O_WRONLY\|O_NOCTTY\|O_NDELAY)) >= 0) {
	va_start(arguments, fmt);
	vdprintf(fd, fmt, arguments);
	va_end(arguments);
	close(fd);
	} else {
	fprintf(stderr, "Bummer, can't print: ");
	va_start(arguments, fmt);
	vfprintf(stderr, fmt, arguments);
	fflush(stderr);
	va_end(arguments);
	}
	}
	}


	/* Set terminal settings to reasonable defaults */
	void set_term( int fd)
	{
	struct termios tty;
	static const char control_characters[] = {
	'\003', '\034', '\177', '\025', '\004', '\0',
	'\1', '\0', '\021', '\023', '\032', '\0', '\022',
	'\017', '\027', '\026', '\0'
	};

	tcgetattr(fd, &tty);

	/* set control chars */
	memcpy(tty.c_cc, control_characters, sizeof(control_characters));

	/* use line dicipline 0 */
	tty.c_line = 0;

	/* Make it be sane */
	//tty.c_cflag &= CBAUD\|CBAUDEX\|CSIZE\|CSTOPB\|PARENB\|PARODD;
	//tty.c_cflag \|= HUPCL\|CLOCAL;

	/* input modes */
	tty.c_iflag = ICRNL\|IXON\|IXOFF;

	/* output modes */
	tty.c_oflag = OPOST\|ONLCR;

	/* local modes */
	tty.c_lflag = ISIG\|ICANON\|ECHO\|ECHOE\|ECHOK\|ECHOCTL\|ECHOKE\|IEXTEN;

	tcsetattr(fd, TCSANOW, &tty);
	}

	/* How much memory does this machine have? */
	static int mem_total()
	{
	char s[80];
	char *p = "/proc/meminfo";
	FILE *f;
	const char pattern[] = "MemTotal:";

	if ((f = fopen(p, "r")) < 0) {
	message(LOG, "Error opening %s: %s\n", p, strerror( errno));
	return -1;
	}
	while (NULL != fgets(s, 79, f)) {
	p = strstr(s, pattern);
	if (NULL != p) {
	fclose(f);
	return (atoi(p + strlen(pattern)));
	}
	}
	return -1;
	}

	static void console_init()
	{
	int fd;
	int tried_devcons = 0;
	int tried_vtprimary = 0;
	struct serial_struct sr;
	char *s;

	if ((s = getenv("CONSOLE")) != NULL) {
	console = s;
	}
	#if #cpu(sparc)
	/* sparc kernel supports console=tty[ab] parameter which is also
	* passed to init, so catch it here */
	else if ((s = getenv("console")) != NULL) {
	/* remap tty[ab] to /dev/ttyS[01] */
	if (strcmp( s, "ttya" )==0)
	console = SERIAL_CON0;
	else if (strcmp( s, "ttyb" )==0)
	console = SERIAL_CON1;
	}
	#endif
	else {
	struct vt_stat vt;
	static char the_console[13];

	console = the_console;
	/* 2.2 kernels: identify the real console backend and try to use it */
	if (ioctl(0, TIOCGSERIAL, &sr) == 0) {
	/* this is a serial console */
	snprintf( the_console, sizeof the_console, "/dev/ttyS%d", sr.line );
	}
	else if (ioctl(0, VT_GETSTATE, &vt) == 0) {
	/* this is linux virtual tty */
	snprintf( the_console, sizeof the_console, "/dev/tty%d", vt.v_active );
	} else {
	console = _PATH_CONSOLE;
	tried_devcons++;
	}
	}

	while ((fd = open(console, O_RDONLY \| O_NONBLOCK)) < 0) {
	/* Can't open selected console -- try /dev/console */
	if (!tried_devcons) {
	tried_devcons++;
	console = _PATH_CONSOLE;
	continue;
	}
	/* Can't open selected console -- try vt1 */
	if (!tried_vtprimary) {
	tried_vtprimary++;
	console = VT_PRIMARY;
	continue;
	}
	break;
	}
	if (fd < 0)
	/* Perhaps we should panic here? */
	console = "/dev/null";
	else {
	/* check for serial console and disable logging to tty3 & running a
	* shell to tty2 */
	if (ioctl(0,TIOCGSERIAL,&sr) == 0) {
	message(LOG\|CONSOLE, "serial console detected. Disabling 2nd virtual terminal.\r\n", console );
	log = NULL;
	second_console = NULL;
	}
	close(fd);
	}
	message(LOG, "console=%s\n", console );
	}

	static int waitfor(int pid)
	{
	int status, wpid;

	while (1) {
	wpid = wait(&status);
	if (wpid > 0 ) {
	message(LOG, "pid %d exited, status=0x%x.\n", wpid, status);
	break;
	}
	if (wpid == pid )
	break;
	}
	return wpid;
	}

	static pid_t run(char* command,
	char *terminal, int get_enter)
	{
	int i;
	pid_t pid;
	char* tmpCmd;
	char* cmd[255];
	static const char press_enter[] =
	"\nPlease press Enter to activate this console. ";

	if ((pid = fork()) == 0) {
	pid_t shell_pgid = getpid ();

	/* Clean up */
	close(0);
	close(1);
	close(2);
	setsid();

	if (device_open(terminal, O_RDWR) < 0) {
	message(LOG\|CONSOLE, "Bummer, can't open %s\r\n", terminal);
	exit(1);
	}
	dup(0);
	dup(0);
	/* Grab control of the terminal. */
	if (tcsetpgrp (0, getpgrp()) < 0) {
	message(LOG\|CONSOLE, "tcsetpgrp error: %s\r\n", strerror(errno));
	}
	set_term(0);

	/* Reset signal handlers set for parent process */
	signal(SIGUSR1, SIG_DFL);
	signal(SIGUSR2, SIG_DFL);
	signal(SIGINT, SIG_DFL);
	signal(SIGTERM, SIG_DFL);


	if (get_enter==TRUE) {
	/*
	* Save memory by not exec-ing anything large (like a shell)
	* before the user wants it. This is critical if swap is not
	* enabled and the system has low memory. Generally this will
	* be run on the second virtual console, and the first will
	* be allowed to start a shell or whatever an init script
	* specifies.
	*/
	char c;
	message(LOG, "Waiting for enter to start '%s' (pid %d, console %s)\r\n",
	command, shell_pgid, terminal );
	write(fileno(stdout), press_enter, sizeof(press_enter) - 1);
	read(fileno(stdin), &c, 1);
	}

	/* Convert command (char) into cmd (char, one word per string) /
	for (tmpCmd=command, i=0; (tmpCmd=strsep(&command, " \t")) != NULL;) {
	if (*tmpCmd != '\0') {
	cmd[i] = tmpCmd;
	tmpCmd++;
	i++;
	}
	}
	cmd[i] = NULL;

	/* Log the process name and args */
	message(LOG, "Starting pid %d, console %s: '%s'\r\n",
	shell_pgid, terminal, cmd[0]);

	/* Now run it. The new program will take over this PID,
	* so nothing further in init.c should be run. */
	execvp(cmd[0], cmd);

	/* We're still here? Some error happened. */
	message(LOG\|CONSOLE, "Bummer, could not run '%s': %s\n", cmd[0],
	strerror(errno));
	exit(-1);
	}
	return pid;
	}

	/* Make sure there is enough memory to do something useful. *
	* Calls swapon if needed so be sure /proc is mounted. */
	static void check_memory()
	{
	struct stat statbuf;

	if (mem_total() > 3500)
	return;

	if (stat("/etc/fstab", &statbuf) == 0) {
	/* Try to turn on swap */
	waitfor(run("/bin/swapon swapon -a", log, FALSE));
	if (mem_total() < 3500)
	goto goodnight;
	} else
	goto goodnight;
	return;

	goodnight:
	message(CONSOLE, "Sorry, your computer does not have enough memory.\r\n");
	while (1) sleep(1);
	}

	#ifndef DEBUG_INIT
	static void shutdown_system(void)
	{
	/* Allow Ctrl-Alt-Del to reboot system. */
	reboot(RB_ENABLE_CAD);
	message(CONSOLE, "\r\nThe system is going down NOW !!\r\n");
	sync();

	/* Send signals to every process _except_ pid 1 */
	message(CONSOLE, "Sending SIGHUP to all processes.\r\n");
	kill(-1, SIGHUP);
	sleep(2);
	sync();

	message(CONSOLE, "Sending SIGKILL to all processes.\r\n");
	kill(-1, SIGKILL);
	sleep(1);

	message(CONSOLE, "Disabling swap.\r\n");
	waitfor(run( "swapoff -a", console, FALSE));
	message(CONSOLE, "Unmounting filesystems.\r\n");
	waitfor(run( "umount -a", console, FALSE));
	sync();
	if (kernel_version > 0 && kernel_version <= 2 * 65536 + 2 * 256 + 11) {
	/* bdflush, kupdate not needed for kernels >2.2.11 */
	message(CONSOLE, "Flushing buffers.\r\n");
	bdflush(1, 0);
	sync();
	}
	}

	static void halt_signal(int sig)
	{
	shutdown_system();
	message(CONSOLE,
	"The system is halted. Press CTRL-ALT-DEL or turn off power\r\n");
	sync();
	#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,2,0)
	if (sig == SIGUSR2)
	reboot(RB_POWER_OFF);
	else
	#endif
	reboot(RB_HALT_SYSTEM);
	exit(0);
	}

	static void reboot_signal(int sig)
	{
	shutdown_system();
	message(CONSOLE, "Please stand by while rebooting the system.\r\n");
	sync();
	reboot(RB_AUTOBOOT);
	exit(0);
	}

	#endif

	void new_initAction (const struct initActionType *a,
	char* process, char* cons)
	{
	initAction* newAction;

	/* If BusyBox detects that a serial console is in use,
	* then entries containing non-empty id fields will _not_ be run.
	*/
	if (second_console != NULL && *cons != '\0')
	return;

	newAction = calloc ((size_t)(1), sizeof(initAction));
	if (!newAction) {
	fprintf(stderr, "Memory allocation failure\n");
	while (1) sleep(1);
	}
	newAction->nextPtr = initActionList;
	initActionList = newAction;
	strncpy( newAction->process, process, 255);
	newAction->action = a->action;
	if (*cons != '\0')
	strncpy(newAction->console, cons, 255);
	else
	strncpy(newAction->console, console, 255);
	newAction->pid = 0;
	}

	void delete_initAction (initAction *action)
	{
	initAction a, b=NULL;
	for( a=initActionList ; a; b=a, a=a->nextPtr) {
	if (a == action && b != NULL) {
	b->nextPtr=a->nextPtr;
	free( a);
	break;
	}
	}
	}

	/* NOTE that if BB_FEATURE_USE_INITTAB is NOT defined,
	* then parse_inittab() simply adds in some default
	* actions(i.e runs INIT_SCRIPT and then starts a pair
	* of "askfirst" shells. If BB_FEATURE_USE_INITTAB
	* _is_ defined, but /etc/inittab is missing == same
	* default behavior.
	* */
	void parse_inittab(void)
	{
	#ifdef BB_FEATURE_USE_INITTAB
	FILE* file;
	char buf[256], buf1[256];
	char p, q, r, s;
	const struct initActionType *a = actions;
	int foundIt;


	file = fopen(INITTAB, "r");
	if (file == NULL) {
	/* No inittab file -- set up some default behavior */
	#endif
	/* Askfirst shell on tty1 */
	new_initAction( &(actions[3]), SHELL, console );
	/* Askfirst shell on tty2 */
	if (second_console != NULL)
	new_initAction( &(actions[3]), SHELL, second_console );
	/* sysinit */
	new_initAction( &(actions[0]), INIT_SCRIPT, console );

	return;
	#ifdef BB_FEATURE_USE_INITTAB
	}

	while ( fgets(buf, 255, file) != NULL) {
	foundIt=FALSE;
	for(p = buf; p == ' ' \|\| p == '\t'; p++);
	if (p == '#' \|\| p == '\n') continue;

	/* Trim the trailing \n */
	q = strrchr( p, '\n');
	if (q != NULL)
	*q='\0';

	/* Keep a copy around for posterity's sake (and error msgs) */
	strcpy(buf1, buf);

	/* Grab the ID field */
	s=p;
	p = strchr( p, ':');
	if ( p != NULL \|\| *(p+1) != '\0' ) {
	*p='\0';
	++p;
	}

	/* Now peal off the process field from the end
	* of the string */
	q = strrchr( p, ':');
	if ( q == NULL \|\| *(q+1) == '\0' ) {
	fprintf(stderr, "Bad inittab entry: %s\n", buf1);
	continue;
	} else {
	*q='\0';
	++q;
	}

	/* Now peal off the action field */
	r = strrchr( p, ':');
	if ( r == NULL \|\| *(r+1) == '\0') {
	fprintf(stderr, "Bad inittab entry: %s\n", buf1);
	continue;
	} else {
	++r;
	}

	/* Ok, now process it */
	a = actions;
	while (a->name != 0) {
	if (strcmp(a->name, r) == 0) {
	new_initAction( a, q, s);
	foundIt=TRUE;
	}
	a++;
	}
	if (foundIt==TRUE)
	continue;
	else {
	/* Choke on an unknown action */
	fprintf(stderr, "Bad inittab entry: %s\n", buf1);
	}
	}
	return;
	#endif
	}

	extern int init_main(int argc, char **argv)
	{
	initAction *a;
	pid_t wpid;
	int status;

	#ifndef DEBUG_INIT
	/* Expect to be PID 1 iff we are run as init (not linuxrc) */
	if (getpid() != 1 && strstr(argv[0], "init")!=NULL ) {
	usage( "init\n\nInit is the parent of all processes.\n\n"
	"This version of init is designed to be run only by the kernel\n");
	}

	/* from the controlling terminal */
	setsid();

	/* Set up sig handlers -- be sure to clear all of these in run() */
	signal(SIGUSR1, halt_signal);
	signal(SIGUSR2, reboot_signal);
	signal(SIGINT, reboot_signal);
	signal(SIGTERM, reboot_signal);

	/* Turn off rebooting via CTL-ALT-DEL -- we get a
	* SIGINT on CAD so we can shut things down gracefully... */
	reboot(RB_DISABLE_CAD);
	#endif

	/* Figure out where the default console should be */
	console_init();

	/* Close whatever files are open, and reset the console. */
	close(0);
	close(1);
	close(2);
	set_term(0);

	/* Make sure PATH is set to something sane */
	putenv(_PATH_STDPATH);


	/* Hello world */
	#ifndef DEBUG_INIT
	message(CONSOLE\|LOG,
	"init started: BusyBox v%s (%s) multi-call binary\r\n",
	BB_VER, BB_BT);
	#else
	message(CONSOLE\|LOG,
	"init(%d) started: BusyBox v%s (%s) multi-call binary\r\n",
	getpid(), BB_VER, BB_BT);
	#endif


	/* Mount /proc */
	if (mount ("proc", "/proc", "proc", 0, 0) == 0) {
	message(CONSOLE\|LOG, "Mounting /proc: done.\n");
	kernel_version = get_kernel_revision();
	} else
	message(CONSOLE\|LOG, "Mounting /proc: failed!\n");

	/* Make sure there is enough memory to do something useful. */
	check_memory();

	/* Check if we are supposed to be in single user mode */
	if ( argc > 1 && (!strcmp(argv[1], "single") \|\|
	!strcmp(argv[1], "-s") \|\| !strcmp(argv[1], "1")))
	{
	/* Ask first then start a shell on tty2 */
	if (second_console != NULL)
	new_initAction( &(actions[3]), SHELL, second_console);
	/* Ask first then start a shell on tty1 */
	new_initAction( &(actions[3]), SHELL, console);
	} else {
	/* Not in single user mode -- see what inittab says */

	/* NOTE that if BB_FEATURE_USE_INITTAB is NOT defined,
	* then parse_inittab() simply adds in some default
	* actions(i.e runs INIT_SCRIPT and then starts a pair
	* of "askfirst" shells */
	parse_inittab();
	}

	/* Now run everything that needs to be run */

	/* First run the sysinit command */
	for( a=initActionList ; a; a=a->nextPtr) {
	if (a->action == SYSINIT) {
	waitfor(run(a->process, console, FALSE));
	/* Now remove the "sysinit" entry from the list */
	delete_initAction( a);
	}
	}
	/* Next run anything that wants to block */
	for( a=initActionList ; a; a=a->nextPtr) {
	if (a->action == WAIT) {
	waitfor(run(a->process, console, FALSE));
	/* Now remove the "wait" entry from the list */
	delete_initAction( a);
	}
	}
	/* Next run anything to be run only once */
	for( a=initActionList ; a; a=a->nextPtr) {
	if (a->action == ONCE) {
	run(a->process, console, FALSE);
	/* Now remove the "once" entry from the list */
	delete_initAction( a);
	}
	}

	/* Now run the looping stuff for the rest of forever */
	while (1) {
	for( a=initActionList ; a; a=a->nextPtr) {
	/* Only run stuff with pid==0. If they have
	* a pid, that means they are still running */
	if (a->pid == 0) {
	switch(a->action) {
	case RESPAWN:
	/* run the respawn stuff */
	a->pid = run(a->process, console, FALSE);
	break;
	case ASKFIRST:
	/* run the askfirst stuff */
	a->pid = run(a->process, console, TRUE);
	break;
	/* silence the compiler's incessant whining */
	default:
	break;
	}
	}
	}
	/* Wait for a child process to exit */
	wpid = wait(&status);
	if (wpid > 0 ) {
	/* Find out who died and clean up their corpse */
	for( a=initActionList ; a; a=a->nextPtr) {
	if (a->pid==wpid) {
	a->pid=0;
	message(LOG, "Process '%s' (pid %d) exited. Scheduling it for restart.\n",
	a->process, wpid);
	}
	}
	}
	sleep(1);
	}
	}