system_cmds-279.tar.gz

[apple/system_cmds.git] / init.tproj / init.c

/*
 * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
 * 
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this
 * file.
 * 
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 * 
 * @APPLE_LICENSE_HEADER_END@
 */
/*-
 * Copyright (c) 1991, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Donn Seeley at Berkeley Software Design, Inc.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the University of
 *      California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/param.h>
#include <sys/sysctl.h>
#include <sys/wait.h>

#include <db.h>
#include <errno.h>
#include <fcntl.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include <time.h>
#include <ttyent.h>
#include <unistd.h>
#include <paths.h>

#include <stdarg.h>

#ifdef SECURE
#include <pwd.h>
#endif

#include "pathnames.h"

/*
 * Until the mythical util.h arrives...
 */
extern int login_tty __P((int));
extern int logout __P((const char *));
extern void logwtmp __P((const char *, const char *, const char *));

/*
 * Sleep times; used to prevent thrashing.
 */
#define GETTY_SPACING            5      /* N secs minimum getty spacing */
#define GETTY_SLEEP             30      /* sleep N secs after spacing problem */
#define WINDOW_WAIT              3      /* wait N secs after starting window */
#define STALL_TIMEOUT           30      /* wait N secs after warning */
#define DEATH_WATCH             10      /* wait N secs for procs to die */
#define FAILED_HW_PASS           5      /* wait N secs before croaking user */

void handle __P((sig_t, ...));
void delset __P((sigset_t *, ...));

void stall __P((char *, ...));
void warning __P((char *, ...));
void emergency __P((char *, ...));
void disaster __P((int));
void badsys __P((int));

/*
 * We really need a recursive typedef...
 * The following at least guarantees that the return type of (*state_t)()
 * is sufficiently wide to hold a function pointer.
 */
typedef long (*state_func_t) __P((void));
typedef state_func_t (*state_t) __P((void));

state_func_t single_user __P((void));
state_func_t runcom __P((void));
state_func_t read_ttys __P((void));
state_func_t multi_user __P((void));
state_func_t clean_ttys __P((void));
state_func_t catatonia __P((void));
state_func_t death __P((void));

enum { AUTOBOOT, FASTBOOT, BOOT_SCRIPT } runcom_mode = AUTOBOOT;
int runcom_boot = 1;    /* Run the rc.boot script */
int runcom_verbose = 0;
int runcom_safe = 0;

void transition __P((state_t));
state_t requested_transition = runcom;

void setctty __P((char *, int));


// gvdl@next.com 14 Aug 1995
//   - from ~apps/loginwindow_proj/loginwindow/common.h
#define REALLY_EXIT_TO_CONSOLE                  229

// From old init.c
// These flags are used in the se_flags field of the init_session structure
#define SE_SHUTDOWN     0x1             /* session won't be restarted */

// The flags below control what sort of getty is launched.
#define SE_GETTY_LAUNCH 0x30    /* What type of getty to launch */ 
#define SE_COMMON       0x00    /* Usual command that is run - getty */
#define SE_ONERROR      0x10    /* Command to run if error condition occurs.
                                 * This will almost always be the windowserver
                                 * and loginwindow.  This is so if the w.s.
                                 * ever dies, that the naive user (stan)
                                 * doesn't ever see the console window. */
#define SE_ONOPTION     0x20    /* Command to run when loginwindow exits with
                                 * special error code (229).  This signifies
                                 * that the user typed "console" at l.w. and
                                 * l.w. wants to exit and have init run getty
                                 * which will then put up a console window. */

typedef struct _se_command {
        char    *path;          /* what to run on that port */
        char    **argv;         /* pre-parsed argument array */
} se_cmd_t;

typedef struct init_session {
        int     se_index;               /* index of entry in ttys file */
        pid_t   se_process;             /* controlling process */
        time_t  se_started;             /* used to avoid thrashing */
        int     se_flags;               /* status of session */
        char    *se_device;             /* filename of port */
        se_cmd_t se_getty;              /* what to run on that port */
        se_cmd_t se_window;             /* window system (started only once) */
        se_cmd_t se_onerror;            /* See SE_ONERROR above */
        se_cmd_t se_onoption;           /* See SE_ONOPTION above */
        struct  init_session *se_prev;
        struct  init_session *se_next;
} session_t;

void free_session __P((session_t *));
session_t *new_session __P((session_t *, int, struct ttyent *));
session_t *sessions;

char **construct_argv __P((char *));
void collect_child __P((pid_t));
pid_t start_getty __P((session_t *));
void transition_handler __P((int));
void alrm_handler __P((int));
void setsecuritylevel __P((int));
int getsecuritylevel __P((void));
int setupargv __P((session_t *, struct ttyent *));
int clang;

void clear_session_logs __P((session_t *));

int start_session_db __P((void));
void add_session __P((session_t *));
void del_session __P((session_t *));
session_t *find_session __P((pid_t));
DB *session_db;

/*
 * The mother of all processes.
 */
int
main(argc, argv)
        int argc;
        char **argv;
{
        int c;
        struct sigaction sa;
        sigset_t mask;


        /* Dispose of random users. */
        if (getuid() != 0) {
                (void)fprintf(stderr, "init: %s\n", strerror(EPERM));
                exit (1);
        }

        /* System V users like to reexec init. */
        if (getpid() != 1) {
                (void)fprintf(stderr, "init: already running\n");
                exit (1);
        }

        /*
         * Note that this does NOT open a file...
         * Does 'init' deserve its own facility number?
         */
        openlog("init", LOG_CONS|LOG_ODELAY, LOG_AUTH);

        /*
         * Create an initial session.
         */
        if (setsid() < 0)
                warning("initial setsid() failed: %m");

        /*
         * Establish an initial user so that programs running
         * single user do not freak out and die (like passwd).
         */
        if (setlogin("root") < 0)
                warning("setlogin() failed: %m");

        /*
         * This code assumes that we always get arguments through flags,
         * never through bits set in some random machine register.
         */

#ifdef DEBUG
        {
            int i;
            for (i = 0; i <= argc; i++) {
                if (argv[i])
                    warning("init argument %d: '%s'", i, argv[i]);
                else
                    warning("init argument %d: ***NULL***", i);
            }
        }
#endif

        while ((c = getopt(argc, argv, "sfbvx")) != -1) {
#ifdef DEBUG
                warning("handling init argument '-%c'", c);
#endif
                switch (c) {
                case 's':
                        requested_transition = single_user;
                        break;
                case 'f':
                        runcom_mode = FASTBOOT;
                        break;
                case 'b':
                        runcom_boot = 0;        // Don't runcom rc.boot
                        break;
                case 'v':
                        runcom_verbose = 1;
                        break;
                case 'x':
                        runcom_safe = 1;
                        break;
                default:
                        warning("unrecognized flag '-%c'", c);
                        break;
                }
        }

        if (optind != argc)
                warning("ignoring excess arguments");

        /*
         * We catch or block signals rather than ignore them,
         * so that they get reset on exec.
         */
        handle(badsys, SIGSYS, 0);
        handle(disaster, SIGABRT, SIGFPE, SIGILL, SIGSEGV,
               SIGBUS, SIGXCPU, SIGXFSZ, 0);
        handle(transition_handler, SIGHUP, SIGTERM, SIGTSTP, 0);
        handle(alrm_handler, SIGALRM, 0);
        sigfillset(&mask);
        delset(&mask, SIGABRT, SIGFPE, SIGILL, SIGSEGV, SIGBUS, SIGSYS,
                SIGXCPU, SIGXFSZ, SIGHUP, SIGTERM, SIGTSTP, SIGALRM, 0);
        sigprocmask(SIG_SETMASK, &mask, (sigset_t *) 0);
        sigemptyset(&sa.sa_mask);
        sa.sa_flags = 0;
        sa.sa_handler = SIG_IGN;
        (void) sigaction(SIGTTIN, &sa, (struct sigaction *)0);
        (void) sigaction(SIGTTOU, &sa, (struct sigaction *)0);

        /*
         * Paranoia.
         */
        close(0);
        close(1);
        close(2);

        if (runcom_boot)
        {
            int old_rc_mode = runcom_mode;

            runcom_mode = BOOT_SCRIPT;
            if (runcom() == (state_func_t) single_user)
                requested_transition = single_user; // Error in script
            runcom_mode = old_rc_mode;
        }

        /*
         * Start the state machine.
         */
        transition(requested_transition);

        /*
         * Should never reach here.
         */
        return 1;
}

/*
 * Associate a function with a signal handler.
 */
void
handle(sig_t handler, ...)
{
        int sig;
        struct sigaction sa;
        int mask_everything;
        va_list ap;
        va_start(ap, handler);

        sa.sa_handler = handler;
        sigfillset(&mask_everything);

        while (sig = va_arg(ap, int)) {
                sa.sa_mask = mask_everything;
                /* XXX SA_RESTART? */
                sa.sa_flags = sig == SIGCHLD ? SA_NOCLDSTOP : 0;
                sigaction(sig, &sa, (struct sigaction *) 0);
        }
        va_end(ap);
}

/*
 * Delete a set of signals from a mask.
 */
void
delset(sigset_t *maskp, ...)
{
        int sig;
        va_list ap;
        va_start(ap, maskp);

        while (sig = va_arg(ap, int))
                sigdelset(maskp, sig);
        va_end(ap);
}

/*
 * Log a message and sleep for a while (to give someone an opportunity
 * to read it and to save log or hardcopy output if the problem is chronic).
 * NB: should send a message to the session logger to avoid blocking.
 */
void
stall(char *message, ...)
{
        va_list ap;
        va_start(ap, message);

        vsyslog(LOG_ALERT, message, ap);
        va_end(ap);
        sleep(STALL_TIMEOUT);
}

/*
 * Like stall(), but doesn't sleep.
 * If cpp had variadic macros, the two functions could be #defines for another.
 * NB: should send a message to the session logger to avoid blocking.
 */
void
warning(char *message, ...)
{
        va_list ap;
        va_start(ap, message);

        vsyslog(LOG_ALERT, message, ap);
        va_end(ap);
}

/*
 * Log an emergency message.
 * NB: should send a message to the session logger to avoid blocking.
 */
void
emergency(char *message, ...)
{
        va_list ap;
        va_start(ap, message);

        vsyslog(LOG_EMERG, message, ap);
        va_end(ap);
}

/*
 * Catch a SIGSYS signal.
 *
 * These may arise if a system does not support sysctl.
 * We tolerate up to 25 of these, then throw in the towel.
 */
void
badsys(sig)
        int sig;
{
        static int badcount = 0;

        if (badcount++ < 25)
                return;
        disaster(sig);
}

/*
 * Catch an unexpected signal.
 */
void
disaster(sig)
        int sig;
{
        emergency("fatal signal: %s",
                sig < (unsigned) NSIG ? sys_siglist[sig] : "unknown signal");

        sleep(STALL_TIMEOUT);
        _exit(sig);             /* reboot */
}

/*
 * Get the security level of the kernel.
 */
int
getsecuritylevel()
{
#ifdef KERN_SECURELVL
        int name[2], curlevel;
        size_t len;
        extern int errno;

        name[0] = CTL_KERN;
        name[1] = KERN_SECURELVL;
        len = sizeof curlevel;
        if (sysctl(name, 2, &curlevel, &len, NULL, 0) == -1) {
                emergency("cannot get kernel security level: %s",
                    strerror(errno));
                return (-1);
        }
        return (curlevel);
#else
        return (-1);
#endif
}

/*
 * Set the security level of the kernel.
 */
void
setsecuritylevel(newlevel)
        int newlevel;
{
#ifdef KERN_SECURELVL
        int name[2], curlevel;
        extern int errno;

        curlevel = getsecuritylevel();
        if (newlevel == curlevel)
                return;
        name[0] = CTL_KERN;
        name[1] = KERN_SECURELVL;
        if (sysctl(name, 2, NULL, NULL, &newlevel, sizeof newlevel) == -1) {
                emergency(
                    "cannot change kernel security level from %d to %d: %s",
                    curlevel, newlevel, strerror(errno));
                return;
        }
#ifdef SECURE
        warning("kernel security level changed from %d to %d",
            curlevel, newlevel);
#endif
#endif
}

/*
 * Change states in the finite state machine.
 * The initial state is passed as an argument.
 */
void
transition(s)
        state_t s;
{
        for (;;)
                s = (state_t) (*s)();
}

/*
 * Close out the accounting files for a login session.
 * NB: should send a message to the session logger to avoid blocking.
 */
void
clear_session_logs(sp)
        session_t *sp;
{
        char *line = sp->se_device + sizeof(_PATH_DEV) - 1;

        if (logout(line))
                logwtmp(line, "", "");
}

/*
 * Start a session and allocate a controlling terminal.
 * Only called by children of init after forking.
 */
void
setctty(name, flags)
        char *name;
        int flags;
{
        int fd;

        (void) revoke(name);
        if ((fd = open(name, flags | O_RDWR)) == -1) {
                stall("can't open %s: %m", name);
                _exit(1);
        }
        if (login_tty(fd) == -1) {
                stall("can't get %s for controlling terminal: %m", name);
                _exit(1);
        }
}

#if m68k
/*
 * Taken from etc/halt/halt.c
 */

#include <stdio.h>
#include <signal.h>
#include <sgtty.h>

static void shutend(void)
{
        register i;

        acct(0);
        for (i = 0; i < 10; i++)
                close(i);

        logwtmp("~", "shutdown", "");
}

static void do_halt(void)
{
        char sbuf [40];
        int halthowto = RB_HALT;

        (void) kill(-1, SIGTERM);       /* one chance to catch it */

        sprintf (sbuf, "Invalid hardware password, halting machine...\n");
        write (1, sbuf, strlen (sbuf));

        signal(SIGALRM, SIG_DFL);
        shutend();
        sync();

        signal(SIGALRM, alrm_handler);
        alarm(FAILED_HW_PASS);
        pause();

        syscall(SYS_reboot, halthowto);
}

/*
 * Taken from lib/gen/getpass.c
 */

static char *gethwpasswd(char *prompt)
{
    struct termios term;
    register char *p;
    register c;
    static char pbuf[9];
    int echo;

    (void) tcgetattr(1, &term);
    if (echo = (term.c_lflag & ECHO))
    {
        term.c_lflag &= ~ECHO;
        (void) tcsetattr(1, TCSAFLUSH|TCSASOFT, &term);
    }

    write(2, prompt, strlen(prompt));

    for (p = pbuf; (c = getchar()) != '\n' && c != EOF; )
        if (p < &pbuf[8])
            *p++ = c;
    *p = '\0';

    p = "\n";
    write(2, p, strlen(p));

    if (echo)
    {
        term.c_lflag |= ECHO;
        (void) tcsetattr(1, TCSAFLUSH|TCSASOFT, &term);
    }

    return(pbuf);
}


static char *hw_passwd (void)
{
    char sbuf[40];
    static char buffer [12];
    struct nvram_info nvi;
    int    vidfd, count;
    
    if ((vidfd = open ("/dev/vid0", O_RDONLY, 0)) == -1)
        return NULL;
    
    if (ioctl (vidfd, DKIOCGNVRAM, &nvi) == -1)
        return NULL;
    
    if (nvi.ni_hw_pwd != HW_PWD)
        return NULL;
    else
    {

        for (count = 0; count < NVRAM_HW_PASSWD; count++)
            nvi.ni_ep[count] ^= 'N';
        strncpy(buffer, nvi.ni_ep, NVRAM_HW_PASSWD);
        /* ni_ep is not necessarily null terminated */

        // gvdl I sure hope it is 'cause bad things will happen otherwise

        return buffer;
    }
}


#endif  m68k


static void
do_security_check(void)
{
#if m68k
    char sbuf[128];
    char *try, *passwd;
    int retries = 0;

    /*
     * If there is a hardware passwd, we want to 
     * prompt the user for it.  The write will be 
     * to the console window because of the O_POPUP flag.
     */
    passwd = hw_passwd();
    write (1, "\n\n", 2);

    if (passwd != NULL)
    {
        do
        {
            try = gethwpasswd ("Enter hardware password:");
            if (strncmp (try, passwd, NVRAM_HW_PASSWD) == 0)
            {
                execl(shell, minus, (char *)0);
                exit (0);
            }
            else
            {
                sprintf (sbuf, "Password incorrect.\n\n");
                write (1, sbuf, strlen (sbuf));
            }
        }
        while (++retries < 3);
        do_halt();
    }
#elif defined(SECURE)
    struct ttyent *typ;
    struct passwd *pp;
    static const char banner[] =
            "Enter root password, or ^D to go multi-user\n";
    char *clear, *password;

    /*
     * Check the root password.
     * We don't care if the console is 'on' by default;
     * it's the only tty that can be 'off' and 'secure'.
     */
    typ = getttynam("console");
    pp = getpwnam("root");
    if (typ && (typ->ty_status & TTY_SECURE) == 0 && pp)
    {
        write(2, banner, sizeof banner - 1);
        for (;;)
        {
            clear = getpass("Password:");
            if (clear == 0 || *clear == '\0')
                _exit(0);
            password = crypt(clear, pp->pw_passwd);
            memset(clear, 0, _PASSWORD_LEN);
            if (strcmp(password, pp->pw_passwd) == 0)
                break;
            warning("single-user login failed\n");
        }
    }
    endttyent();
    endpwent();
#endif /* SECURE */
}

/*
 * Bring the system up single user.
 */
state_func_t
single_user()
{
        pid_t pid, wpid;
        int status;
        sigset_t mask;
        char *shell = _PATH_BSHELL;
        char *argv[2];
        /*
         * If the kernel is in secure mode, downgrade it to insecure mode.
         */
        if (getsecuritylevel() > 0)
                setsecuritylevel(0);

        if ((pid = fork()) == 0) {
                /*
                 * Start the single user session.
                 */
                setctty(_PATH_CONSOLE, O_POPUP);

                do_security_check();

#ifdef DEBUGSHELL
                {
                        char altshell[128], *cp = altshell;
                        int num;

#define SHREQUEST \
        "Enter pathname of shell or RETURN for sh: "
                        (void)write(STDERR_FILENO,
                            SHREQUEST, sizeof(SHREQUEST) - 1);
                        while ((num = read(STDIN_FILENO, cp, 1)) != -1 &&
                            num != 0 && *cp != '\n' && cp < &altshell[127])
                                        cp++;
                        *cp = '\0';
                        if (altshell[0] != '\0')
                                shell = altshell;
                }
#endif /* DEBUGSHELL */

                /*
                 * Unblock signals.
                 * We catch all the interesting ones,
                 * and those are reset to SIG_DFL on exec.
                 */
                sigemptyset(&mask);
                sigprocmask(SIG_SETMASK, &mask, (sigset_t *) 0);

                /*
                 * Set up the PATH to be approriate for the root user.
                 */
                setenv("PATH", _PATH_STDPATH, 1);

                /*
                 * We're dropping into the console; set TERM appropriately.
                 */
                setenv("TERM", "vt100", 1);

                /*
                 * Fire off a shell.
                 * If the default one doesn't work, try the Bourne shell.
                 */
                argv[0] = "-sh";
                argv[1] = 0;
                execv(shell, argv);
                emergency("can't exec %s for single user: %m", shell);
                execv(_PATH_BSHELL, argv);
                emergency("can't exec %s for single user: %m", _PATH_BSHELL);
                sleep(STALL_TIMEOUT);
                _exit(1);
        }

        if (pid == -1) {
                /*
                 * We are seriously hosed.  Do our best.
                 */
                emergency("can't fork single-user shell, trying again");
                while (waitpid(-1, (int *) 0, WNOHANG) > 0)
                        continue;
                return (state_func_t) single_user;
        }

        requested_transition = 0;
        do {
                if ((wpid = waitpid(-1, &status, WUNTRACED)) != -1)
                        collect_child(wpid);
                if (wpid == -1) {
                        if (errno == EINTR)
                                continue;
                        warning("wait for single-user shell failed: %m; restarting");
                        return (state_func_t) single_user;
                }
                if (wpid == pid && WIFSTOPPED(status)) {
                        warning("init: shell stopped, restarting\n");
                        kill(pid, SIGCONT);
                        wpid = -1;
                }
        } while (wpid != pid && !requested_transition);

        if (requested_transition)
                return (state_func_t) requested_transition;

        if (!WIFEXITED(status)) {
                if (WTERMSIG(status) == SIGKILL) { 
                        /* 
                         *  reboot(8) killed shell? 
                         */
                        warning("single user shell terminated.");
                        sleep(STALL_TIMEOUT);
                        _exit(0);
                } else {        
                        warning("single user shell terminated, restarting");
                        return (state_func_t) single_user;
                }
        }

        runcom_mode = FASTBOOT;
        return (state_func_t) runcom;
}

/*
 * Run the system startup script.
 */
state_func_t
runcom()
{
        pid_t pid, wpid;
        int status;
        char *argv[4];
        char options[4];
        struct sigaction sa;

        if ((pid = fork()) == 0) {
                sigemptyset(&sa.sa_mask);
                sa.sa_flags = 0;
                sa.sa_handler = SIG_IGN;
                (void) sigaction(SIGTSTP, &sa, (struct sigaction *)0);
                (void) sigaction(SIGHUP, &sa, (struct sigaction *)0);

                setctty(_PATH_CONSOLE, 0);

                argv[0] = "sh";

                if (runcom_mode == BOOT_SCRIPT)
                {
                    argv[1] = _PATH_RUNCOM_BOOT;
                    argv[2] = requested_transition == single_user
                            ? "singleuser" : "multiuser";
                }
                else /* runcom_mode != BOOT_SCRIPT */
                {
                    argv[1] = _PATH_RUNCOM;

                    switch(runcom_mode) {
                    case AUTOBOOT:
                        argv[2] = "autoboot";
                        break;
                    default:
                        argv[2] = "multiuser";
                        break;
                    }
                }

                if (runcom_verbose || runcom_safe)
                {
                    int i = 0;

                    options[i++] = '-';
                    if (runcom_verbose) options[i++] = 'v';
                    if (runcom_safe   ) options[i++] = 'x';
                    options[i] = '\0';

                    argv[3] = options;
                }
                else
                {
                    argv[3] = 0;
                }

                argv[4] = 0;

#ifdef DEBUG
                {
                    int i;
                    for (i = 0; i <= 4; i++) {
                        if (argv[i])
                            warning("%s argument: %s", _PATH_RUNCOM, argv[i]);
                    }
                }
#endif

                sigprocmask(SIG_SETMASK, &sa.sa_mask, (sigset_t *) 0);

                execv(_PATH_BSHELL, argv);
                stall("can't exec %s for %s: %m", _PATH_BSHELL, _PATH_RUNCOM);
                _exit(1);       /* force single user mode */
        }

        if (pid == -1) {
                emergency("can't fork for %s on %s: %m",
                        _PATH_BSHELL, _PATH_RUNCOM);
                while (waitpid(-1, (int *) 0, WNOHANG) > 0)
                        continue;
                sleep(STALL_TIMEOUT);
                return (state_func_t) single_user;
        }

        /*
         * Copied from single_user().  This is a bit paranoid.
         */
        do {
                if ((wpid = waitpid(-1, &status, WUNTRACED)) != -1)
                        collect_child(wpid);
                if (wpid == -1) {
                        if (errno == EINTR)
                                continue;
                        warning("wait for %s on %s failed: %m; going to single user mode",
                                _PATH_BSHELL, _PATH_RUNCOM);
                        return (state_func_t) single_user;
                }
                if (wpid == pid && WIFSTOPPED(status)) {
                        warning("init: %s on %s stopped, restarting\n",
                                _PATH_BSHELL, _PATH_RUNCOM);
                        kill(pid, SIGCONT);
                        wpid = -1;
                }
        } while (wpid != pid);

        if (WIFSIGNALED(status) && WTERMSIG(status) == SIGTERM &&
            requested_transition == catatonia) {
                /* /etc/rc executed /sbin/reboot; wait for the end quietly */
                sigset_t s;

                sigfillset(&s);
                for (;;)
                        sigsuspend(&s);
        }

        if (!WIFEXITED(status)) {
                warning("%s on %s terminated abnormally, going to single user mode",
                        _PATH_BSHELL, _PATH_RUNCOM);
                return (state_func_t) single_user;
        }

        if (WEXITSTATUS(status))
                return (state_func_t) single_user;

        runcom_mode = AUTOBOOT;         /* the default */
        /* NB: should send a message to the session logger to avoid blocking. */
        logwtmp("~", "reboot", "");
        return (state_func_t) read_ttys;
}

/*
 * Open the session database.
 *
 * NB: We could pass in the size here; is it necessary?
 */
int
start_session_db()
{
        if (session_db && (*session_db->close)(session_db))
                emergency("session database close: %s", strerror(errno));
        if ((session_db = dbopen(NULL, O_RDWR, 0, DB_HASH, NULL)) == 0) {
                emergency("session database open: %s", strerror(errno));
                return (1);
        }
        return (0);
                
}

/*
 * Add a new login session.
 */
void
add_session(sp)
        session_t *sp;
{
        DBT key;
        DBT data;

        key.data = &sp->se_process;
        key.size = sizeof sp->se_process;
        data.data = &sp;
        data.size = sizeof sp;

        if ((*session_db->put)(session_db, &key, &data, 0))
                emergency("insert %d: %s", sp->se_process, strerror(errno));
}

/*
 * Delete an old login session.
 */
void
del_session(sp)
        session_t *sp;
{
        DBT key;

        key.data = &sp->se_process;
        key.size = sizeof sp->se_process;

        if ((*session_db->del)(session_db, &key, 0))
                emergency("delete %d: %s", sp->se_process, strerror(errno));
}

/*
 * Look up a login session by pid.
 */
session_t *
find_session(pid_t pid)
{
        DBT key;
        DBT data;
        session_t *ret;

        key.data = &pid;
        key.size = sizeof pid;
        if ((*session_db->get)(session_db, &key, &data, 0) != 0)
                return 0;
        memmove(&ret, data.data, sizeof(ret));
        return ret;
}

/*
 * Construct an argument vector from a command line.
 */
char **
construct_argv(command)
        char *command;
{
        register int argc = 0;
        register char **argv = (char **) malloc(((strlen(command) + 1) / 2 + 1)
                                                * sizeof (char *));
        static const char separators[] = " \t";

        if ((argv[argc++] = strtok(command, separators)) == 0)
                return 0;
        while (argv[argc++] = strtok((char *) 0, separators))
                continue;
        return argv;
}

/*
 * Deallocate a session descriptor.
 */

static __inline__ void free_command(se_cmd_t *se_cmd)
{
    if (se_cmd->path)
    {
        free(se_cmd->path);
        free(se_cmd->argv);
    }
}

void
free_session(sp)
        register session_t *sp;
{
    free(sp->se_device);
    free_command(&sp->se_getty);
    free_command(&sp->se_window);
    free_command(&sp->se_onerror);
    free_command(&sp->se_onoption);
    memset(sp, '\0', sizeof(*sp));      // a bit of defensive programming

    free(sp);
}

static int setup_command(se_cmd_t *se_cmd, char *command, char *arg )
{

    char *commandWithArg;

    commandWithArg = malloc( strlen( command) + strlen( arg) + 2);
    (void) sprintf(commandWithArg, "%s %s", command, arg);

        free_command(se_cmd);

        se_cmd->path = commandWithArg;
        se_cmd->argv = construct_argv(commandWithArg);
        if (se_cmd->argv == NULL)
        {
                free(se_cmd->path);
                se_cmd->path = NULL;
                return 0;
        }
        return 1;
}

/*
 * Calculate getty and if useful window argv vectors.
 */
int
setupargv(sp, typ)
        session_t *sp;
        struct ttyent *typ;
{
    char *type;

    if ( !setup_command(&sp->se_getty, typ->ty_getty, typ->ty_name) )
    {
        type = "getty";
        goto bad_args;
    }

    if (typ->ty_window
    && !setup_command(&sp->se_window, typ->ty_window, typ->ty_name) )
    {
        type = "window";
        goto bad_args;
    }

    if (typ->ty_onerror
    && !setup_command(&sp->se_onerror, typ->ty_onerror, typ->ty_name) )
    {
        type = "onerror";
        goto bad_args;
    }

    if (typ->ty_onoption
    && !setup_command(&sp->se_onoption, typ->ty_onoption, typ->ty_name) )
    {
        type = "onoption";
        goto bad_args;
    }

    return 1;

bad_args:
    warning("can't parse %s for port %s", type, sp->se_device);
    return 0;
}


/*
 * Allocate a new session descriptor.
 */
session_t *
new_session(sprev, session_index, typ)
        session_t *sprev;
        int session_index;
        register struct ttyent *typ;
{
        register session_t *sp;

        if ((typ->ty_status & TTY_ON) == 0 ||
            typ->ty_name == 0 ||
            typ->ty_getty == 0)
                return 0;

        sp = (session_t *) malloc(sizeof (session_t));
        memset(sp, 0, sizeof *sp);

        sp->se_index = session_index;

        sp->se_device = malloc(sizeof(_PATH_DEV) + strlen(typ->ty_name));
        (void) sprintf(sp->se_device, "%s%s", _PATH_DEV, typ->ty_name);

        if (setupargv(sp, typ) == 0) {
                free_session(sp);
                return (0);
        }

        sp->se_next = 0;
        if (sprev == 0) {
                sessions = sp;
                sp->se_prev = 0;
        } else {
                sprev->se_next = sp;
                sp->se_prev = sprev;
        }

        return sp;
}

/*
 * Walk the list of ttys and create sessions for each active line.
 */
state_func_t
read_ttys()
{
        int session_index = 0;
        register session_t *sp, *snext;
        register struct ttyent *typ;

        /*
         * Destroy any previous session state.
         * There shouldn't be any, but just in case...
         */
        for (sp = sessions; sp; sp = snext) {
                if (sp->se_process)
                        clear_session_logs(sp);
                snext = sp->se_next;
                free_session(sp);
        }
        sessions = 0;
        if (start_session_db())
                return (state_func_t) single_user;

        /*
         * Allocate a session entry for each active port.
         * Note that sp starts at 0.
         */
        while (typ = getttyent())
                if (snext = new_session(sp, ++session_index, typ))
                        sp = snext;

        endttyent();

        return (state_func_t) multi_user;
}

/*
 * Start a window system running.
 */
static pid_t
start_window_system(session_t *sp)
{
        pid_t pid;
        sigset_t mask;

        if ((pid = fork()) == -1) {
                emergency("can't fork for window system on port %s: %m",
                        sp->se_device);
                /* hope that getty fails and we can try again */
                return -1;
        }

        if (pid)
                return pid;

        sigemptyset(&mask);
        sigprocmask(SIG_SETMASK, &mask, (sigset_t *) 0);

        if (setsid() < 0)
                emergency("setsid failed (window) %m");

        execv(sp->se_window.argv[0], sp->se_window.argv);
        stall("can't exec window system '%s' for port %s: %m",
                sp->se_window.argv[0], sp->se_device);
        _exit(1);
}

/*
 * Start a login session running.
 */
pid_t
start_getty(sp)
        session_t *sp;
{
        pid_t pid;
        sigset_t mask;
        se_cmd_t *se_cmd;
        const char *session_type = NULL;
        time_t current_time      = time((time_t *) 0);

        // Setup the default values;
        switch (sp->se_flags & SE_GETTY_LAUNCH)
        {
        case SE_ONOPTION:
            if (sp->se_onoption.path)
            {
                se_cmd       = &sp->se_onoption;
                session_type = "onoption";
                break;
            }
            /* No break */

        case SE_ONERROR:
            if (sp->se_onerror.path)
            {
                se_cmd       = &sp->se_onerror;
                session_type = "onerror";
                break;
            }
            /* No break */

        case SE_COMMON:
        default:
            se_cmd       = &sp->se_getty;
            session_type = "getty";
            break;
        }

        if  (sp->se_window.path
        && ((sp->se_flags & SE_GETTY_LAUNCH) != SE_ONOPTION))
        {
                if (start_window_system(sp) == -1)
                        return -1;
        }

        /*
         * fork(), not vfork() -- we can't afford to block.
         */
        if ((pid = fork()) == -1) {
                emergency("can't fork for %s on port %s: %m",
                    session_type, sp->se_device);
                return -1;
        }

        if (pid)
                return pid;

        if (current_time > sp->se_started &&
            current_time - sp->se_started < GETTY_SPACING) {
                warning("%s repeating too quickly on port %s, sleeping",
                        session_type, sp->se_device);
                sleep((unsigned) GETTY_SLEEP);
        }

        sigemptyset(&mask);
        sigprocmask(SIG_SETMASK, &mask, (sigset_t *) 0);

        execv(se_cmd->argv[0], se_cmd->argv);
        stall("can't exec %s '%s' for port %s: %m", session_type,
                se_cmd->argv[0], sp->se_device);
        _exit(1);
}

/*
 * Collect exit status for a child.
 * If an exiting login, start a new login running.
 */
void
collect_child(pid_t pid)
{
        register session_t *sp, *sprev, *snext;

        if ( !sessions)
                return;

        if ( !(sp = find_session(pid)) )
                return;

        clear_session_logs(sp);
        del_session(sp);
        sp->se_process = 0;

        if (sp->se_flags & SE_SHUTDOWN) {
                if (sprev = sp->se_prev)
                        sprev->se_next = sp->se_next;
                else
                        sessions = sp->se_next;
                if (snext = sp->se_next)
                        snext->se_prev = sp->se_prev;
                free_session(sp);
                return;
        }

        if ((pid = start_getty(sp)) == -1) {
                /* serious trouble */
                requested_transition = clean_ttys;
                return;
        }

        sp->se_process = pid;
        sp->se_started = time((time_t *) 0);
        sp->se_flags  &= ~SE_GETTY_LAUNCH; // clear down getty launch type
        add_session(sp);
}

/*
 * Catch a signal and request a state transition.
 */
void
transition_handler(sig)
        int sig;
{

        switch (sig) {
        case SIGHUP:
                requested_transition = clean_ttys;
                break;
        case SIGTERM:
                requested_transition = death;
                break;
        case SIGTSTP:
                requested_transition = catatonia;
                break;
        default:
                requested_transition = 0;
                break;
        }
}

/*
 * Take the system multiuser.
 */
state_func_t
multi_user()
{
        pid_t pid;
        register session_t *sp;

        requested_transition = 0;

        /*
         * If the administrator has not set the security level to -1
         * to indicate that the kernel should not run multiuser in secure
         * mode, and the run script has not set a higher level of security 
         * than level 1, then put the kernel into secure mode.
         */
        if (getsecuritylevel() == 0)
                setsecuritylevel(1);

        for (sp = sessions; sp; sp = sp->se_next) {
                if (sp->se_process)
                        continue;
                if ((pid = start_getty(sp)) == -1) {
                        /* serious trouble */
                        requested_transition = clean_ttys;
                        break;
                }
                sp->se_process = pid;
                sp->se_started = time((time_t *) 0);
                add_session(sp);
        }

        while (!requested_transition)
        {
                int status;
                session_t *sp;

                pid = waitpid(-1, &status, 0);
                if (!sessions || !(sp = find_session(pid)))
                        continue;

                if (WIFSIGNALED(status))
                    sp->se_flags |= SE_ONERROR;
                else if (WEXITSTATUS(status) == REALLY_EXIT_TO_CONSOLE)
                { /* WIFEXITED(status) assumed */
                    sp->se_flags |= SE_ONOPTION;
                }
                else
                    sp->se_flags |= SE_ONERROR;

                if (pid != -1)
                        collect_child(pid);
        }

        return (state_func_t) requested_transition;
}

/*
 * This is an n-squared algorithm.  We hope it isn't run often...
 */
state_func_t
clean_ttys()
{
        register session_t *sp, *sprev;
        register struct ttyent *typ;
        register int session_index = 0;
        register int devlen;

        if (! sessions)
                return (state_func_t) multi_user;

        devlen = sizeof(_PATH_DEV) - 1;
        while (typ = getttyent()) {
                ++session_index;

                for (sprev = 0, sp = sessions; sp; sprev = sp, sp = sp->se_next)
                        if (strcmp(typ->ty_name, sp->se_device + devlen) == 0)
                                break;

                if (sp) {
                        if (sp->se_index != session_index) {
                                warning("port %s changed utmp index from %d to %d",
                                       sp->se_device, sp->se_index,
                                       session_index);
                                sp->se_index = session_index;
                        }
                        if ((typ->ty_status & TTY_ON) == 0 ||
                            typ->ty_getty == 0) {
                                sp->se_flags |= SE_SHUTDOWN;
                                kill(sp->se_process, SIGHUP);
                                continue;
                        }
                        sp->se_flags &= ~SE_SHUTDOWN;
                        if (setupargv(sp, typ) == 0) {
                                warning("can't parse getty for port %s",
                                        sp->se_device);
                                sp->se_flags |= SE_SHUTDOWN;
                                kill(sp->se_process, SIGHUP);
                        }
                        continue;
                }

                new_session(sprev, session_index, typ);
        }

        endttyent();

        return (state_func_t) multi_user;
}

/*
 * Block further logins.
 */
state_func_t
catatonia()
{
        register session_t *sp;

        for (sp = sessions; sp; sp = sp->se_next)
                sp->se_flags |= SE_SHUTDOWN;

        return (state_func_t) multi_user;
}

/*
 * Note SIGALRM.
 */
void
alrm_handler(sig)
        int sig;
{
        clang = 1;
}

/*
 * Bring the system down to single user.
 */
state_func_t
death()
{
        register session_t *sp;
        register int i;
        pid_t pid;
        static const int death_sigs[3] = { SIGHUP, SIGTERM, SIGKILL };

        for (sp = sessions; sp; sp = sp->se_next)
                sp->se_flags |= SE_SHUTDOWN;

        /* NB: should send a message to the session logger to avoid blocking. */
        logwtmp("~", "shutdown", "");

        for (i = 0; i < 3; ++i) {
                if (kill(-1, death_sigs[i]) == -1 && errno == ESRCH)
                        return (state_func_t) single_user;

                clang = 0;
                alarm(DEATH_WATCH);
                do
                        if ((pid = waitpid(-1, (int *)0, 0)) != -1)
                                collect_child(pid);
                while (clang == 0 && errno != ECHILD);

                if (errno == ECHILD)
                        return (state_func_t) single_user;
        }

        warning("some processes would not die; ps axl advised");

        return (state_func_t) single_user;
}