--- src/sys/sys/event.h	Fri Jul  1 20:28:32 2005
+++ src/sys/sys/event.h	Wed Sep 27 17:35:09 2006
@@ -38,8 +38,9 @@
 #define EVFILT_TIMER		(-7)	/* timers */
 #define EVFILT_NETDEV		(-8)	/* network devices */
 #define EVFILT_FS		(-9)	/* filesystem events */
+#define EVFILT_USER		(-10)	/* user events */
 
-#define EVFILT_SYSCOUNT		9
+#define EVFILT_SYSCOUNT		10
 
 #define EV_SET(kevp_, a, b, c, d, e, f) do {	\
 	struct kevent *kevp = (kevp_);		\
--- src/sys/kern/kern_event.c	Mon Sep  4 21:17:25 2006
+++ src/sys/kern/kern_event.c	Wed Sep 27 18:53:25 2006
@@ -132,6 +132,9 @@
 static int	filt_timerattach(struct knote *kn);
 static void	filt_timerdetach(struct knote *kn);
 static int	filt_timer(struct knote *kn, long hint);
+static int	filt_userattach(struct knote *kn);
+static void	filt_userdetach(struct knote *kn);
+static int	filt_user(struct knote *kn, long hint);
 
 static struct filterops file_filtops =
 	{ 1, filt_fileattach, NULL, NULL };
@@ -142,6 +145,8 @@
 	{ 0, filt_procattach, filt_procdetach, filt_proc };
 static struct filterops timer_filtops =
 	{ 0, filt_timerattach, filt_timerdetach, filt_timer };
+static struct filterops user_filtops =
+	{ 0, filt_userattach, filt_userdetach, filt_user };
 
 static uma_zone_t	knote_zone;
 static int 		kq_ncallouts = 0;
@@ -247,6 +252,7 @@
 	{ &timer_filtops },			/* EVFILT_TIMER */
 	{ &file_filtops },			/* EVFILT_NETDEV */
 	{ &fs_filtops },			/* EVFILT_FS */
+	{ &user_filtops },			/* EVFILT_USER */
 };
 
 /*
@@ -495,6 +501,27 @@
 {
 
 	return (kn->kn_data != 0);
+}
+
+static int
+filt_userattach(struct knote *kn)
+{
+	kn->kn_flags |= EV_ONESHOT;		/* automatically set */
+	kn->kn_status &= ~KN_DETACHED;		/* knlist_add usually sets it */
+	return (0);
+}
+
+static void
+filt_userdetach(struct knote *kn)
+{
+	kn->kn_status |= KN_DETACHED;	/* knlist_remove usually clears it */
+}
+
+static int
+filt_user(struct knote *kn, long hint)
+{
+
+	return (1);
 }
 
 /*