BSD 4.4 Lite sbin Sources

Note:  XNSrouted and routed NOT imported here, they shall be imported with
usr.sbin.

1 files changed, 1297 insertions, 0 deletions

diff --git a/sbin/init/init.c b/sbin/init/init.c
new file mode 100644
index 0000000..ff03598
--- /dev/null
+++ b/sbin/init/init.c
@@ -0,0 +1,1297 @@
+/*-
+ * 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.
+ */
+
+#ifndef lint
+static char copyright[] =
+"@(#) Copyright (c) 1991, 1993\n\
+	The Regents of the University of California.  All rights reserved.\n";
+#endif /* not lint */
+
+#ifndef lint
+static char sccsid[] = "@(#)init.c	8.1 (Berkeley) 7/15/93";
+#endif /* not lint */
+
+#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>
+
+#ifdef __STDC__
+#include <stdarg.h>
+#else
+#include <varargs.h>
+#endif
+
+#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 */
+
+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 } runcom_mode = AUTOBOOT;
+
+void transition __P((state_t));
+state_t requested_transition = runcom;
+
+void setctty __P((char *));
+
+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 */
+#define	SE_SHUTDOWN	0x1		/* session won't be restarted */
+	char	*se_device;		/* filename of port */
+	char	*se_getty;		/* what to run on that port */
+	char	**se_getty_argv;	/* pre-parsed argument array */
+	char	*se_window;		/* window system (started only once) */
+	char	**se_window_argv;	/* pre-parsed argument array */
+	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 start_window_system __P((session_t *));
+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.
+	 */
+	while ((c = getopt(argc, argv, "sf")) != -1)
+		switch (c) {
+		case 's':
+			requested_transition = single_user;
+			break;
+		case 'f':
+			runcom_mode = FASTBOOT;
+			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);
+
+	/*
+	 * Start the state machine.
+	 */
+	transition(requested_transition);
+
+	/*
+	 * Should never reach here.
+	 */
+	return 1;
+}
+
+/*
+ * Associate a function with a signal handler.
+ */
+void
+#ifdef __STDC__
+handle(sig_t handler, ...)
+#else
+handle(va_alist)
+	va_dcl
+#endif
+{
+	int sig;
+	struct sigaction sa;
+	int mask_everything;
+	va_list ap;
+#ifndef __STDC__
+	sig_t handler;
+
+	va_start(ap);
+	handler = va_arg(ap, sig_t);
+#else
+	va_start(ap, handler);
+#endif
+
+	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
+#ifdef __STDC__
+delset(sigset_t *maskp, ...)
+#else
+delset(va_alist)
+	va_dcl
+#endif
+{
+	int sig;
+	va_list ap;
+#ifndef __STDC__
+	sigset_t *maskp;
+
+	va_start(ap);
+	maskp = va_arg(ap, sigset_t *);
+#else
+	va_start(ap, maskp);
+#endif
+
+	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
+#ifdef __STDC__
+stall(char *message, ...)
+#else
+stall(va_alist)
+	va_dcl
+#endif
+{
+	va_list ap;
+#ifndef __STDC__
+	char *message;
+
+	va_start(ap);
+	message = va_arg(ap, char *);
+#else
+	va_start(ap, message);
+#endif
+
+	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
+#ifdef __STDC__
+warning(char *message, ...)
+#else
+warning(va_alist)
+	va_dcl
+#endif
+{
+	va_list ap;
+#ifndef __STDC__
+	char *message;
+
+	va_start(ap);
+	message = va_arg(ap, char *);
+#else
+	va_start(ap, message);
+#endif
+
+	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
+#ifdef __STDC__
+emergency(char *message, ...)
+#else
+emergency(va_alist)
+	va_dcl
+#endif
+{
+	va_list ap;
+#ifndef __STDC__
+	char *message;
+
+	va_start(ap);
+	message = va_arg(ap, char *);
+#else
+	va_start(ap, message);
+#endif
+
+	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)
+	char *name;
+{
+	int fd;
+
+	(void) revoke(name);
+	sleep (2);			/* leave DTR low */
+	if ((fd = open(name, 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);
+	}
+}
+
+/*
+ * 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];
+#ifdef SECURE
+	struct ttyent *typ;
+	struct passwd *pp;
+	static const char banner[] =
+		"Enter root password, or ^D to go multi-user\n";
+	char *clear, *password;
+#endif
+
+	/*
+	 * 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);
+
+#ifdef SECURE
+		/*
+		 * 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);
+				bzero(clear, _PASSWORD_LEN);
+				if (strcmp(password, pp->pw_passwd) == 0)
+					break;
+				warning("single-user login failed\n");
+			}
+		}
+		endttyent();
+		endpwent();
+#endif /* SECURE */
+
+#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);
+
+		/*
+		 * 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];
+	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);
+
+		argv[0] = "sh";
+		argv[1] = _PATH_RUNCOM;
+		argv[2] = runcom_mode == AUTOBOOT ? "autoboot" : 0;
+		argv[3] = 0;
+
+		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 *
+#ifdef __STDC__
+find_session(pid_t pid)
+#else
+find_session(pid)
+	pid_t pid;
+#endif
+{
+	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;
+	bcopy(data.data, (char *)&ret, 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.
+ */
+void
+free_session(sp)
+	register session_t *sp;
+{
+	free(sp->se_device);
+	if (sp->se_getty) {
+		free(sp->se_getty);
+		free(sp->se_getty_argv);
+	}
+	if (sp->se_window) {
+		free(sp->se_window);
+		free(sp->se_window_argv);
+	}
+	free(sp);
+}
+
+/*
+ * 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));
+	bzero(sp, 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;
+}
+
+/*
+ * Calculate getty and if useful window argv vectors.
+ */
+int
+setupargv(sp, typ)
+	session_t *sp;
+	struct ttyent *typ;
+{
+
+	if (sp->se_getty) {
+		free(sp->se_getty);
+		free(sp->se_getty_argv);
+	}
+	sp->se_getty = malloc(strlen(typ->ty_getty) + strlen(typ->ty_name) + 2);
+	(void) sprintf(sp->se_getty, "%s %s", typ->ty_getty, typ->ty_name);
+	sp->se_getty_argv = construct_argv(sp->se_getty);
+	if (sp->se_getty_argv == 0) {
+		warning("can't parse getty for port %s", sp->se_device);
+		free(sp->se_getty);
+		sp->se_getty = 0;
+		return (0);
+	}
+	if (typ->ty_window) {
+		if (sp->se_window)
+			free(sp->se_window);
+		sp->se_window = strdup(typ->ty_window);
+		sp->se_window_argv = construct_argv(sp->se_window);
+		if (sp->se_window_argv == 0) {
+			warning("can't parse window for port %s",
+				sp->se_device);
+			free(sp->se_window);
+			sp->se_window = 0;
+			return (0);
+		}
+	}
+	return (1);
+}
+
+/*
+ * 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.
+ */
+void
+start_window_system(sp)
+	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;
+	}
+
+	if (pid)
+		return;
+
+	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;
+	time_t current_time = time((time_t *) 0);
+
+	/*
+	 * fork(), not vfork() -- we can't afford to block.
+	 */
+	if ((pid = fork()) == -1) {
+		emergency("can't fork for getty on port %s: %m", sp->se_device);
+		return -1;
+	}
+
+	if (pid)
+		return pid;
+
+	if (current_time > sp->se_started &&
+	    current_time - sp->se_started < GETTY_SPACING) {
+		warning("getty repeating too quickly on port %s, sleeping",
+		        sp->se_device);
+		sleep((unsigned) GETTY_SLEEP);
+	}
+
+	if (sp->se_window) {
+		start_window_system(sp);
+		sleep(WINDOW_WAIT);
+	}
+
+	sigemptyset(&mask);
+	sigprocmask(SIG_SETMASK, &mask, (sigset_t *) 0);
+
+	execv(sp->se_getty_argv[0], sp->se_getty_argv);
+	stall("can't exec getty '%s' for port %s: %m",
+		sp->se_getty_argv[0], sp->se_device);
+	_exit(1);
+}
+
+/*
+ * Collect exit status for a child.
+ * If an exiting login, start a new login running.
+ */
+void
+#ifdef __STDC__
+collect_child(pid_t pid)
+#else
+collect_child(pid)
+	pid_t pid;
+#endif
+{
+	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);
+	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)
+		if ((pid = waitpid(-1, (int *) 0, 0)) != -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;
+}