diff --git a/lib/libc/sys/reboot.2 b/lib/libc/sys/reboot.2
index ad66ee5646db..d51468d8c358 100644
--- a/lib/libc/sys/reboot.2
+++ b/lib/libc/sys/reboot.2
@@ -81,6 +81,9 @@ for more information.
 .It Dv RB_HALT
 the processor is simply halted; no reboot takes place.
 This option should be used with caution.
+.It Dv RB_POWEROFF
+After halting, the shutdown code will do what it can to turn
+of the power. This requires hardware support.
 .It Dv RB_INITNAME
 An option allowing the specification of an init program (see
 .Xr init 8 )
diff --git a/share/man/man9/at_shutdown.9 b/share/man/man9/at_shutdown.9
index 73e3a1f0bced..47e7a448c6e0 100644
--- a/share/man/man9/at_shutdown.9
+++ b/share/man/man9/at_shutdown.9
@@ -23,7 +23,7 @@
 .\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 .\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 .\"
-.\" $Id: at_shutdown.9,v 1.1 1996/08/19 02:22:15 julian Exp $
+.\" $Id: at_shutdown.9,v 1.2 1996/08/21 21:43:19 mpp Exp $
 .\" "
 .Dd August 15, 1996
 .Os
@@ -33,14 +33,14 @@
 .Nm rm_at_shutdown
 .Nd ask that a function be run at shutdown.
 .Sh SYNOPSIS
-.Fd #include <sys/systm.h>
 .Fd #include <sys/reboot.h>
+.Fd #include <sys/systm.h>
 
 .Ft typedef void \*(lp*bootlist_fn\*(rp \*(lpint, void *\*(rp;
 
 
 .Ft void
-.Fn at_shutdown "bootlist_fn func" "void *arg" 
+.Fn at_shutdown "bootlist_fn func" "void *arg" "int when"
 .Ft void
 .Fn rm_at_shutdown "bootlist_fn func" "void *arg"
 .Sh DESCRIPTION
@@ -62,6 +62,16 @@ and
 .Ar arg
 arguments as the corresponding call to
 .Fn at_shutdown .
+There are two shutdown queues, one run before the final sync and one after.
+The last argument to 
+.Nm at_shutdown
+should be one of 
+.Em SHUTDOWN_PRE_SYNC
+or
+.Em SHUTDOWN_POST_SYNC
+to specify which queue should be used.
+.Nm rm_at_shutdown
+will remove an entry from either queue.
 .Pp
 .Sh RETURN VALUES
 .Nm at_shutdown
diff --git a/sys/dev/vn/vn.c b/sys/dev/vn/vn.c
index 1a0364498b75..70a31ef959f5 100644
--- a/sys/dev/vn/vn.c
+++ b/sys/dev/vn/vn.c
@@ -38,7 +38,7 @@
  * from: Utah Hdr: vn.c 1.13 94/04/02
  *
  *	from: @(#)vn.c	8.6 (Berkeley) 4/1/94
- *	$Id: vn.c,v 1.38 1996/08/19 20:06:41 julian Exp $
+ *	$Id: vn.c,v 1.39 1996/08/19 21:06:39 julian Exp $
  */
 
 /*
@@ -621,7 +621,7 @@ vn_drvinit(void *unused)
 
 	if( ! vn_devsw_installed ) {
 		bdevsw_add_generic(BDEV_MAJOR,CDEV_MAJOR, &vn_bdevsw);
-		if(at_shutdown(&vnshutdown,NULL)) {
+		if(at_shutdown(&vnshutdown, NULL, SHUTDOWN_POST_SYNC)) {
 			printf("vn: could not install shutdown hook\n");
 			return;
 		}
diff --git a/sys/kern/kern_exit.c b/sys/kern/kern_exit.c
index fc58173a6c2f..02016353cdb9 100644
--- a/sys/kern/kern_exit.c
+++ b/sys/kern/kern_exit.c
@@ -36,7 +36,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)kern_exit.c	8.7 (Berkeley) 2/12/94
- * $Id: kern_exit.c,v 1.36 1996/08/19 02:28:23 julian Exp $
+ * $Id: kern_exit.c,v 1.37 1996/08/20 07:17:47 smpatel Exp $
  */
 
 #include "opt_ktrace.h"
@@ -130,11 +130,11 @@ exit1(p, rv)
 	vmsizmon();
 #endif
 	/* 
-	 * Check if any LKMs need anything done at process exit
+	 * Check if any LKMs need anything done at process exit.
 	 * e.g. SYSV IPC stuff
 	 * XXX what if one of these generates an error?
 	 */
-	while(ep) {
+	while (ep) {
 		(*ep->function)(p);
 		ep = ep->next;
 	}
@@ -501,11 +501,12 @@ proc_reparent(child, parent)
 	child->p_pptr = parent;
 }
 
-/*********************************************************
- * general routines to handle adding/deleting items on the
+/*
+ * The next two functions are to handle adding/deleting items on the
  * exit callout list
- *****
- * Take the arguments given and put them onto the exit callout list.
+ * 
+ * at_exit():
+ * Take the arguments given and put them onto the exit callout list,
  * However first make sure that it's not already there.
  * returns 0 on success.
  */
@@ -513,39 +514,43 @@ int
 at_exit(exitlist_fn function)
 {
 	ele_p ep;
-	if(rm_at_exit(function)) {
+
+	/* Be noisy if the programmer has lost track of things */
+	if (rm_at_exit(function)) 
 		printf("exit callout entry already present\n");
-	}
-	ep = malloc(sizeof(*ep),M_TEMP,M_NOWAIT);
-	if(!ep) return ENOMEM;
+	ep = malloc(sizeof(*ep), M_TEMP, M_NOWAIT);
+	if (ep == NULL)
+		return (ENOMEM);
 	ep->next = exit_list;
 	ep->function = function;
 	exit_list = ep;
-	return 0;
+	return (0);
 }
 /*
  * Scan the exit callout list for the given items and remove them.
  * Returns the number of items removed.
+ * Logically this can only be 0 or 1.
  */
 int
 rm_at_exit(exitlist_fn function)
 {
-	ele_p *epp,ep;
-	int count = 0;
+	ele_p *epp, ep;
+	int count;
 
+	count = 0;
 	epp = &exit_list;
 	ep = *epp;
-	while(ep) {
-		if(ep->function == function) {
+	while (ep) {
+		if (ep->function == function) {
 			*epp = ep->next;
-			free(ep,M_TEMP);
+			free(ep, M_TEMP);
 			count++;
 		} else {
 			epp = &ep->next;
 		}
 		ep = *epp;
 	}
-	return count;
+	return (count);
 }
 
 
diff --git a/sys/kern/kern_fork.c b/sys/kern/kern_fork.c
index f6bb2840748b..d037fbd8240f 100644
--- a/sys/kern/kern_fork.c
+++ b/sys/kern/kern_fork.c
@@ -36,7 +36,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)kern_fork.c	8.6 (Berkeley) 4/8/94
- * $Id: kern_fork.c,v 1.23 1996/07/31 09:26:34 davidg Exp $
+ * $Id: kern_fork.c,v 1.24 1996/08/19 02:28:24 julian Exp $
  */
 
 #include "opt_ktrace.h"
@@ -65,18 +65,19 @@
 static int fork1 __P((struct proc *p, int flags, int *retval));
 
 /*
- * callout list for things to do at fork time
+ * These are the stuctures used to create a callout list for things to do
+ * when forking a process
  */
 typedef struct fork_list_element {
 	struct fork_list_element *next;
 	forklist_fn function;
 } *fle_p;
 
-static fle_p fork_list;
+static fle_p	fork_list;
 
 #ifndef _SYS_SYSPROTO_H_
 struct fork_args {
-        int     dummy;
+	int     dummy;
 };
 #endif
 
@@ -124,8 +125,9 @@ fork1(p1, flags, retval)
 	struct proc *newproc;
 	int count;
 	static int nextpid, pidchecked = 0;
-	fle_p ep = fork_list;
+	fle_p ep ;
 
+	ep = fork_list;
 	if ((flags & RFPROC) == 0)
 		return (EINVAL);
 	if ((flags & (RFFDG|RFCFDG)) == (RFFDG|RFCFDG))
@@ -346,14 +348,14 @@ fork1(p1, flags, retval)
 	}
 
 	/*
-	 * Both processes are set up, 
-	 * check if any LKMs want to adjust anything
-	 * What if they have an error? XXX
+	 * Both processes are set up, now check if any LKMs want
+	 * to adjust anything.
+	 *   What if they have an error? XXX
 	 */
-        while(ep) {
-                (*ep->function)(p1,p2,flags);
-                ep = ep->next;
-        }
+	while (ep) {
+		(*ep->function)(p1, p2, flags);
+		ep = ep->next;
+	}
 
 	/*
 	 * Make child runnable and add to run queue.
@@ -385,52 +387,57 @@ fork1(p1, flags, retval)
 	return (0);
 }
 
-
-/*********************************************************
- * general routines to handle adding/deleting items on the
- * fork callout list
- *****
- * Take the arguments given and put them onto the fork callout list.
+/*
+ * The next two functionms are general routines to handle adding/deleting
+ * items on the fork callout list.
+ *
+ * at_fork():
+ * Take the arguments given and put them onto the fork callout list,
  * However first make sure that it's not already there.
- * returns 0 on success.
+ * Returns 0 on success or a standard error number.
  */
 int
 at_fork(forklist_fn function)
 {
 	fle_p ep;
-	if(rm_at_fork(function)) {
+
+	/* let the programmer know if he's been stupid */
+	if (rm_at_fork(function)) 
 		printf("fork callout entry already present\n");
-	}
-	ep = malloc(sizeof(*ep),M_TEMP,M_NOWAIT);
-	if(!ep) return ENOMEM;
+	ep = malloc(sizeof(*ep), M_TEMP, M_NOWAIT);
+	if (ep == NULL)
+		return (ENOMEM);
 	ep->next = fork_list;
 	ep->function = function;
 	fork_list = ep;
-	return 0;
+	return (0);
 }
+
 /*
  * Scan the exit callout list for the given items and remove them.
  * Returns the number of items removed.
+ * Theoretically this value can only be 0 or 1.
  */
 int
 rm_at_fork(forklist_fn function)
 {
-	fle_p *epp,ep;
-	int count = 0;
+	fle_p *epp, ep;
+	int count;
 
+	count= 0;
 	epp = &fork_list;
 	ep = *epp;
-	while(ep) {
-		if(ep->function == function) {
+	while (ep) {
+		if (ep->function == function) {
 			*epp = ep->next;
-			free(ep,M_TEMP);
+			free(ep, M_TEMP);
 			count++;
 		} else {
 			epp = &ep->next;
 		}
 		ep = *epp;
 	}
-	return count;
+	return (count);
 }
 
 
diff --git a/sys/kern/kern_shutdown.c b/sys/kern/kern_shutdown.c
index 1ded33f77cb3..4d6b555c9b47 100644
--- a/sys/kern/kern_shutdown.c
+++ b/sys/kern/kern_shutdown.c
@@ -36,7 +36,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)kern_shutdown.c	8.3 (Berkeley) 1/21/94
- * $Id: kern_shutdown.c,v 1.1 1996/08/19 02:19:21 julian Exp $
+ * $Id: kern_shutdown.c,v 1.2 1996/08/19 20:06:59 julian Exp $
  */
 
 #include "opt_ddb.h"
@@ -102,7 +102,12 @@ typedef struct shutdown_list_element {
 	void *arg;
 } *sle_p;
 
-static sle_p shutdown_list;
+/*
+ * there are two shutdown lists. Some things need to be shut down
+ * Earlier than others.
+ */
+static sle_p shutdown_list1;
+static sle_p shutdown_list2;
 
 
 
@@ -170,7 +175,7 @@ __dead void
 boot(howto)
 	int howto;
 {
-	sle_p ep = shutdown_list;
+	sle_p ep;
 
 	/*
 	 * eventually the at_shutdown() method will totally replace the
@@ -180,14 +185,15 @@ boot(howto)
 	 */
 	if ((howto & RB_NOSYNC) == 0 ) {
 		printf("\ncleaning up... ");
-                while(*cleanups) {
+                while (*cleanups) {
 			printf("Using obsolete shutdown callout..\n");
 			printf("update code to use at_shutdown()\n");
                         (**cleanups++)();
                 }
 	}
-	while(ep) {
-		shutdown_list = ep->next;
+	ep = shutdown_list1;
+	while (ep) {
+		shutdown_list1 = ep->next;
 		(*ep->function)(howto, ep->arg);
 		ep = ep->next;
 	}
@@ -239,6 +245,12 @@ boot(howto)
 		DELAY(100000);			/* wait for console output to finish */
 		dev_shutdownall(FALSE);
 	}
+	ep = shutdown_list2;
+	while (ep) {
+		shutdown_list2 = ep->next;
+		(*ep->function)(howto, ep->arg);
+		ep = ep->next;
+	}
 	splhigh();
 	if (howto & RB_HALT) {
 		printf("\n");
@@ -378,53 +390,78 @@ panic(const char *fmt, ...)
 	boot(bootopt);
 }
 
-
-/*********************************************************
- * general routines to handle adding/deleting items on the
- * shutdown callout list
- *****
+/*
+ * Two routines to handle adding/deleting items on the
+ * shutdown callout lists
+ *
+ * at_shutdown():
  * Take the arguments given and put them onto the shutdown callout list.
  * However first make sure that it's not already there.
  * returns 0 on success.
  */
 int
-at_shutdown(bootlist_fn function, void *arg)
+at_shutdown(bootlist_fn function, void *arg, int position)
 {
-	sle_p ep;
-	if(rm_at_shutdown(function, arg)) {
-		printf("exit callout entry already present\n");
+	sle_p ep, *epp;
+
+	switch(position) {
+	case SHUTDOWN_PRE_SYNC:
+		epp = &shutdown_list1;
+		break;
+	case SHUTDOWN_POST_SYNC:
+		epp = &shutdown_list2;
+		break;
+	default:
+		printf("bad exit callout list specified\n");
+		return (EINVAL);
 	}
-	ep = malloc(sizeof(*ep),M_TEMP,M_NOWAIT);
-	if(!ep) return ENOMEM;
-	ep->next = shutdown_list;
+	if (rm_at_shutdown(function, arg))
+		printf("exit callout entry already present\n");
+	ep = malloc(sizeof(*ep), M_TEMP, M_NOWAIT);
+	if (ep == NULL)
+		return (ENOMEM);
+	ep->next = *epp;
 	ep->function = function;
 	ep->arg = arg;
-	shutdown_list = ep;
-	return 0;
+	*epp = ep;
+	return (0);
 }
+
 /*
- * Scan the exit callout list for the given items and remove them.
+ * Scan the exit callout lists for the given items and remove them.
  * Returns the number of items removed.
  */
 int
 rm_at_shutdown(bootlist_fn function, void *arg)
 {
-	sle_p *epp,ep;
-	int count = 0;
+	sle_p *epp, ep;
+	int count;
 
-	epp = &shutdown_list;
+	count = 0;
+	epp = &shutdown_list1;
 	ep = *epp;
-	while(ep) {
-		if((ep->function == function) && (ep->arg = arg)) {
+	while (ep) {
+		if ((ep->function == function) && (ep->arg = arg)) {
 			*epp = ep->next;
-			free(ep,M_TEMP);
+			free(ep, M_TEMP);
 			count++;
 		} else {
 			epp = &ep->next;
 		}
 		ep = *epp;
 	}
-	return count;
+	epp = &shutdown_list2;
+	ep = *epp;
+	while (ep) {
+		if ((ep->function == function) && (ep->arg = arg)) {
+			*epp = ep->next;
+			free(ep, M_TEMP);
+			count++;
+		} else {
+			epp = &ep->next;
+		}
+		ep = *epp;
+	}
+	return (count);
 }
 
-
diff --git a/sys/sys/reboot.h b/sys/sys/reboot.h
index b3b3033b72eb..ecf6cb89bd71 100644
--- a/sys/sys/reboot.h
+++ b/sys/sys/reboot.h
@@ -31,7 +31,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)reboot.h	8.3 (Berkeley) 12/13/94
- * $Id: reboot.h,v 1.11 1996/02/24 06:46:17 hsu Exp $
+ * $Id: reboot.h,v 1.11 1996/03/11 02:09:55 hsu Exp $
  */
 
 #ifndef _SYS_REBOOT_H_
@@ -57,6 +57,7 @@
 #define RB_VERBOSE	0x800	/* print all potentially useful info */
 #define	RB_SERIAL	0x1000	/* user serial port as console */
 #define	RB_CDROM	0x2000	/* use cdrom as root */
+#define	RB_POWEROFF	0x4000	/* if you can, turn the power off */
 
 #define	RB_BOOTINFO	0x80000000	/* have `struct bootinfo *' arg */
 
diff --git a/sys/sys/systm.h b/sys/sys/systm.h
index 8a4ccc2bbeb5..1896783568fe 100644
--- a/sys/sys/systm.h
+++ b/sys/sys/systm.h
@@ -36,7 +36,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)systm.h	8.7 (Berkeley) 3/29/95
- * $Id: systm.h,v 1.40 1996/07/01 18:12:13 bde Exp $
+ * $Id: systm.h,v 1.41 1996/08/19 02:19:23 julian Exp $
  */
 
 #ifndef _SYS_SYSTM_H_
@@ -190,10 +190,12 @@ void untimeout(timeout_func_t, void *);
 void	logwakeup __P((void));
 
 /* Various other callout lists that modules might want to know about */
-/* shutdown */
+/* shutdown callout list definitions */
 typedef void (*bootlist_fn)(int,void *);
-int at_shutdown(bootlist_fn function, void *arg);
+int at_shutdown(bootlist_fn function, void *arg, int);
 int rm_at_shutdown(bootlist_fn function, void *arg);
+#define SHUTDOWN_PRE_SYNC 0
+#define SHUTDOWN_POST_SYNC 1
 
 /* forking */ /* XXX not yet */
 typedef void (*forklist_fn)(struct proc *parent,struct proc *child,int flags);