Added knlist_XXX and knote_XXX methods.

1 files changed, 2194 insertions, 0 deletions

diff --git a/freebsd/kern/kern_event.c b/freebsd/kern/kern_event.c
new file mode 100644
index 00000000..54ba63a9
--- /dev/null
+++ b/freebsd/kern/kern_event.c
@@ -0,0 +1,2194 @@
+#include <freebsd/machine/rtems-bsd-config.h>
+
+/*-
+ * Copyright (c) 1999,2000,2001 Jonathan Lemon <jlemon@FreeBSD.org>
+ * Copyright 2004 John-Mark Gurney <jmg@FreeBSD.org>
+ * Copyright (c) 2009 Apple, Inc.
+ * All rights reserved.
+ *
+ * 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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 <freebsd/sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <freebsd/local/opt_ktrace.h>
+
+#include <freebsd/sys/param.h>
+#include <freebsd/sys/systm.h>
+#include <freebsd/sys/kernel.h>
+#include <freebsd/sys/lock.h>
+#include <freebsd/sys/mutex.h>
+#include <freebsd/sys/proc.h>
+#include <freebsd/sys/malloc.h>
+#include <freebsd/sys/unistd.h>
+#include <freebsd/sys/file.h>
+#include <freebsd/sys/filedesc.h>
+#include <freebsd/sys/filio.h>
+#include <freebsd/sys/fcntl.h>
+#include <freebsd/sys/kthread.h>
+#include <freebsd/sys/selinfo.h>
+#include <freebsd/sys/queue.h>
+#include <freebsd/sys/event.h>
+#ifndef __rtems__
+#include <freebsd/sys/eventvar.h>
+#endif /* __rtems__ */
+#include <freebsd/sys/poll.h>
+#include <freebsd/sys/protosw.h>
+#include <freebsd/sys/sigio.h>
+#include <freebsd/sys/signalvar.h>
+#include <freebsd/sys/socket.h>
+#include <freebsd/sys/socketvar.h>
+#include <freebsd/sys/stat.h>
+#include <freebsd/sys/sysctl.h>
+#include <freebsd/sys/sysproto.h>
+#include <freebsd/sys/syscallsubr.h>
+#include <freebsd/sys/taskqueue.h>
+#include <freebsd/sys/uio.h>
+#ifdef KTRACE
+#include <freebsd/sys/ktrace.h>
+#endif
+
+#ifndef __rtems__
+##include <freebsd/vm/uma.h>
+#endif /* __rtems__ */
+
+#ifndef __rtems__
+static MALLOC_DEFINE(M_KQUEUE, "kqueue", "memory for kqueue system");
+
+/*
+ * This lock is used if multiple kq locks are required.  This possibly
+ * should be made into a per proc lock.
+ */
+static struct mtx	kq_global;
+MTX_SYSINIT(kq_global, &kq_global, "kqueue order", MTX_DEF);
+#define KQ_GLOBAL_LOCK(lck, haslck)	do {	\
+	if (!haslck)				\
+		mtx_lock(lck);			\
+	haslck = 1;				\
+} while (0)
+#define KQ_GLOBAL_UNLOCK(lck, haslck)	do {	\
+	if (haslck)				\
+		mtx_unlock(lck);			\
+	haslck = 0;				\
+} while (0)
+
+TASKQUEUE_DEFINE_THREAD(kqueue);
+
+static int	kevent_copyout(void *arg, struct kevent *kevp, int count);
+static int	kevent_copyin(void *arg, struct kevent *kevp, int count);
+static int	kqueue_register(struct kqueue *kq, struct kevent *kev,
+		    struct thread *td, int waitok);
+static int	kqueue_acquire(struct file *fp, struct kqueue **kqp);
+static void	kqueue_release(struct kqueue *kq, int locked);
+static int	kqueue_expand(struct kqueue *kq, struct filterops *fops,
+		    uintptr_t ident, int waitok);
+static void	kqueue_task(void *arg, int pending);
+static int	kqueue_scan(struct kqueue *kq, int maxevents,
+		    struct kevent_copyops *k_ops,
+		    const struct timespec *timeout,
+		    struct kevent *keva, struct thread *td);
+static void 	kqueue_wakeup(struct kqueue *kq);
+static struct filterops *kqueue_fo_find(int filt);
+static void	kqueue_fo_release(int filt);
+
+static fo_rdwr_t	kqueue_read;
+static fo_rdwr_t	kqueue_write;
+static fo_truncate_t	kqueue_truncate;
+static fo_ioctl_t	kqueue_ioctl;
+static fo_poll_t	kqueue_poll;
+static fo_kqfilter_t	kqueue_kqfilter;
+static fo_stat_t	kqueue_stat;
+static fo_close_t	kqueue_close;
+
+static struct fileops kqueueops = {
+	.fo_read = kqueue_read,
+	.fo_write = kqueue_write,
+	.fo_truncate = kqueue_truncate,
+	.fo_ioctl = kqueue_ioctl,
+	.fo_poll = kqueue_poll,
+	.fo_kqfilter = kqueue_kqfilter,
+	.fo_stat = kqueue_stat,
+	.fo_close = kqueue_close,
+};
+
+static int 	knote_attach(struct knote *kn, struct kqueue *kq);
+static void 	knote_drop(struct knote *kn, struct thread *td);
+static void 	knote_enqueue(struct knote *kn);
+static void 	knote_dequeue(struct knote *kn);
+static void 	knote_init(void);
+static struct 	knote *knote_alloc(int waitok);
+static void 	knote_free(struct knote *kn);
+
+static void	filt_kqdetach(struct knote *kn);
+static int	filt_kqueue(struct knote *kn, long hint);
+static int	filt_procattach(struct knote *kn);
+static void	filt_procdetach(struct knote *kn);
+static int	filt_proc(struct knote *kn, long hint);
+static int	filt_fileattach(struct knote *kn);
+static void	filt_timerexpire(void *knx);
+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 void	filt_usertouch(struct knote *kn, struct kevent *kev,
+		    u_long type);
+
+static struct filterops file_filtops =
+	{ 1, filt_fileattach, NULL, NULL };
+static struct filterops kqread_filtops =
+	{ 1, NULL, filt_kqdetach, filt_kqueue };
+/* XXX - move to kern_proc.c?  */
+static struct filterops proc_filtops =
+	{ 0, filt_procattach, filt_procdetach, filt_proc };
+static struct filterops timer_filtops =
+	{ 0, filt_timerattach, filt_timerdetach, filt_timer };
+static struct filterops user_filtops = {
+	.f_attach = filt_userattach,
+	.f_detach = filt_userdetach,
+	.f_event = filt_user,
+	.f_touch = filt_usertouch,
+};
+
+static uma_zone_t	knote_zone;
+static int 		kq_ncallouts = 0;
+static int 		kq_calloutmax = (4 * 1024);
+SYSCTL_INT(_kern, OID_AUTO, kq_calloutmax, CTLFLAG_RW,
+    &kq_calloutmax, 0, "Maximum number of callouts allocated for kqueue");
+
+/* XXX - ensure not KN_INFLUX?? */
+#define KNOTE_ACTIVATE(kn, islock) do { 				\
+	if ((islock))							\
+		mtx_assert(&(kn)->kn_kq->kq_lock, MA_OWNED);		\
+	else								\
+		KQ_LOCK((kn)->kn_kq);					\
+	(kn)->kn_status |= KN_ACTIVE;					\
+	if (((kn)->kn_status & (KN_QUEUED | KN_DISABLED)) == 0)		\
+		knote_enqueue((kn));					\
+	if (!(islock))							\
+		KQ_UNLOCK((kn)->kn_kq);					\
+} while(0)
+#define KQ_LOCK(kq) do {						\
+	mtx_lock(&(kq)->kq_lock);					\
+} while (0)
+#define KQ_FLUX_WAKEUP(kq) do {						\
+	if (((kq)->kq_state & KQ_FLUXWAIT) == KQ_FLUXWAIT) {		\
+		(kq)->kq_state &= ~KQ_FLUXWAIT;				\
+		wakeup((kq));						\
+	}								\
+} while (0)
+#define KQ_UNLOCK_FLUX(kq) do {						\
+	KQ_FLUX_WAKEUP(kq);						\
+	mtx_unlock(&(kq)->kq_lock);					\
+} while (0)
+#define KQ_UNLOCK(kq) do {						\
+	mtx_unlock(&(kq)->kq_lock);					\
+} while (0)
+#define KQ_OWNED(kq) do {						\
+	mtx_assert(&(kq)->kq_lock, MA_OWNED);				\
+} while (0)
+#define KQ_NOTOWNED(kq) do {						\
+	mtx_assert(&(kq)->kq_lock, MA_NOTOWNED);			\
+} while (0)
+#define KN_LIST_LOCK(kn) do {						\
+	if (kn->kn_knlist != NULL)					\
+		kn->kn_knlist->kl_lock(kn->kn_knlist->kl_lockarg);	\
+} while (0)
+#define KN_LIST_UNLOCK(kn) do {						\
+	if (kn->kn_knlist != NULL) 					\
+		kn->kn_knlist->kl_unlock(kn->kn_knlist->kl_lockarg);	\
+} while (0)
+#define	KNL_ASSERT_LOCK(knl, islocked) do {				\
+	if (islocked)							\
+		KNL_ASSERT_LOCKED(knl);				\
+	else								\
+		KNL_ASSERT_UNLOCKED(knl);				\
+} while (0)
+#ifdef INVARIANTS
+#define	KNL_ASSERT_LOCKED(knl) do {					\
+	knl->kl_assert_locked((knl)->kl_lockarg);			\
+} while (0)
+#define	KNL_ASSERT_UNLOCKED(knl) do {					\
+	knl->kl_assert_unlocked((knl)->kl_lockarg);			\
+} while (0)
+#else /* !INVARIANTS */
+#define	KNL_ASSERT_LOCKED(knl) do {} while(0)
+#define	KNL_ASSERT_UNLOCKED(knl) do {} while (0)
+#endif /* INVARIANTS */
+
+#define	KN_HASHSIZE		64		/* XXX should be tunable */
+#define KN_HASH(val, mask)	(((val) ^ (val >> 8)) & (mask))
+
+static int
+filt_nullattach(struct knote *kn)
+{
+
+	return (ENXIO);
+};
+
+struct filterops null_filtops =
+	{ 0, filt_nullattach, NULL, NULL };
+
+/* XXX - make SYSINIT to add these, and move into respective modules. */
+extern struct filterops sig_filtops;
+extern struct filterops fs_filtops;
+
+/*
+ * Table for for all system-defined filters.
+ */
+static struct mtx	filterops_lock;
+MTX_SYSINIT(kqueue_filterops, &filterops_lock, "protect sysfilt_ops",
+	MTX_DEF);
+static struct {
+	struct filterops *for_fop;
+	int for_refcnt;
+} sysfilt_ops[EVFILT_SYSCOUNT] = {
+	{ &file_filtops },			/* EVFILT_READ */
+	{ &file_filtops },			/* EVFILT_WRITE */
+	{ &null_filtops },			/* EVFILT_AIO */
+	{ &file_filtops },			/* EVFILT_VNODE */
+	{ &proc_filtops },			/* EVFILT_PROC */
+	{ &sig_filtops },			/* EVFILT_SIGNAL */
+	{ &timer_filtops },			/* EVFILT_TIMER */
+	{ &null_filtops },			/* former EVFILT_NETDEV */
+	{ &fs_filtops },			/* EVFILT_FS */
+	{ &null_filtops },			/* EVFILT_LIO */
+	{ &user_filtops },			/* EVFILT_USER */
+};
+
+/*
+ * Simple redirection for all cdevsw style objects to call their fo_kqfilter
+ * method.
+ */
+static int
+filt_fileattach(struct knote *kn)
+{
+
+	return (fo_kqfilter(kn->kn_fp, kn));
+}
+
+/*ARGSUSED*/
+static int
+kqueue_kqfilter(struct file *fp, struct knote *kn)
+{
+	struct kqueue *kq = kn->kn_fp->f_data;
+
+	if (kn->kn_filter != EVFILT_READ)
+		return (EINVAL);
+
+	kn->kn_status |= KN_KQUEUE;
+	kn->kn_fop = &kqread_filtops;
+	knlist_add(&kq->kq_sel.si_note, kn, 0);
+
+	return (0);
+}
+
+static void
+filt_kqdetach(struct knote *kn)
+{
+	struct kqueue *kq = kn->kn_fp->f_data;
+
+	knlist_remove(&kq->kq_sel.si_note, kn, 0);
+}
+
+/*ARGSUSED*/
+static int
+filt_kqueue(struct knote *kn, long hint)
+{
+	struct kqueue *kq = kn->kn_fp->f_data;
+
+	kn->kn_data = kq->kq_count;
+	return (kn->kn_data > 0);
+}
+
+/* XXX - move to kern_proc.c?  */
+static int
+filt_procattach(struct knote *kn)
+{
+	struct proc *p;
+	int immediate;
+	int error;
+
+	immediate = 0;
+	p = pfind(kn->kn_id);
+	if (p == NULL && (kn->kn_sfflags & NOTE_EXIT)) {
+		p = zpfind(kn->kn_id);
+		immediate = 1;
+	} else if (p != NULL && (p->p_flag & P_WEXIT)) {
+		immediate = 1;
+	}
+
+	if (p == NULL)
+		return (ESRCH);
+	if ((error = p_cansee(curthread, p))) {
+		PROC_UNLOCK(p);
+		return (error);
+	}
+
+	kn->kn_ptr.p_proc = p;
+	kn->kn_flags |= EV_CLEAR;		/* automatically set */
+
+	/*
+	 * internal flag indicating registration done by kernel
+	 */
+	if (kn->kn_flags & EV_FLAG1) {
+		kn->kn_data = kn->kn_sdata;		/* ppid */
+		kn->kn_fflags = NOTE_CHILD;
+		kn->kn_flags &= ~EV_FLAG1;
+	}
+
+	if (immediate == 0)
+		knlist_add(&p->p_klist, kn, 1);
+
+	/*
+	 * Immediately activate any exit notes if the target process is a
+	 * zombie.  This is necessary to handle the case where the target
+	 * process, e.g. a child, dies before the kevent is registered.
+	 */
+	if (immediate && filt_proc(kn, NOTE_EXIT))
+		KNOTE_ACTIVATE(kn, 0);
+
+	PROC_UNLOCK(p);
+
+	return (0);
+}
+
+/*
+ * The knote may be attached to a different process, which may exit,
+ * leaving nothing for the knote to be attached to.  So when the process
+ * exits, the knote is marked as DETACHED and also flagged as ONESHOT so
+ * it will be deleted when read out.  However, as part of the knote deletion,
+ * this routine is called, so a check is needed to avoid actually performing
+ * a detach, because the original process does not exist any more.
+ */
+/* XXX - move to kern_proc.c?  */
+static void
+filt_procdetach(struct knote *kn)
+{
+	struct proc *p;
+
+	p = kn->kn_ptr.p_proc;
+	knlist_remove(&p->p_klist, kn, 0);
+	kn->kn_ptr.p_proc = NULL;
+}
+
+/* XXX - move to kern_proc.c?  */
+static int
+filt_proc(struct knote *kn, long hint)
+{
+	struct proc *p = kn->kn_ptr.p_proc;
+	u_int event;
+
+	/*
+	 * mask off extra data
+	 */
+	event = (u_int)hint & NOTE_PCTRLMASK;
+
+	/*
+	 * if the user is interested in this event, record it.
+	 */
+	if (kn->kn_sfflags & event)
+		kn->kn_fflags |= event;
+
+	/*
+	 * process is gone, so flag the event as finished.
+	 */
+	if (event == NOTE_EXIT) {
+		if (!(kn->kn_status & KN_DETACHED))
+			knlist_remove_inevent(&p->p_klist, kn);
+		kn->kn_flags |= (EV_EOF | EV_ONESHOT);
+		kn->kn_data = p->p_xstat;
+		kn->kn_ptr.p_proc = NULL;
+		return (1);
+	}
+
+	return (kn->kn_fflags != 0);
+}
+
+/*
+ * Called when the process forked. It mostly does the same as the
+ * knote(), activating all knotes registered to be activated when the
+ * process forked. Additionally, for each knote attached to the
+ * parent, check whether user wants to track the new process. If so
+ * attach a new knote to it, and immediately report an event with the
+ * child's pid.
+ */
+void
+knote_fork(struct knlist *list, int pid)
+{
+	struct kqueue *kq;
+	struct knote *kn;
+	struct kevent kev;
+	int error;
+
+	if (list == NULL)
+		return;
+	list->kl_lock(list->kl_lockarg);
+
+	SLIST_FOREACH(kn, &list->kl_list, kn_selnext) {
+		if ((kn->kn_status & KN_INFLUX) == KN_INFLUX)
+			continue;
+		kq = kn->kn_kq;
+		KQ_LOCK(kq);
+		if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) {
+			KQ_UNLOCK(kq);
+			continue;
+		}
+
+		/*
+		 * The same as knote(), activate the event.
+		 */
+		if ((kn->kn_sfflags & NOTE_TRACK) == 0) {
+			kn->kn_status |= KN_HASKQLOCK;
+			if (kn->kn_fop->f_event(kn, NOTE_FORK | pid))
+				KNOTE_ACTIVATE(kn, 1);
+			kn->kn_status &= ~KN_HASKQLOCK;
+			KQ_UNLOCK(kq);
+			continue;
+		}
+
+		/*
+		 * The NOTE_TRACK case. In addition to the activation
+		 * of the event, we need to register new event to
+		 * track the child. Drop the locks in preparation for
+		 * the call to kqueue_register().
+		 */
+		kn->kn_status |= KN_INFLUX;
+		KQ_UNLOCK(kq);
+		list->kl_unlock(list->kl_lockarg);
+
+		/*
+		 * Activate existing knote and register a knote with
+		 * new process.
+		 */
+		kev.ident = pid;
+		kev.filter = kn->kn_filter;
+		kev.flags = kn->kn_flags | EV_ADD | EV_ENABLE | EV_FLAG1;
+		kev.fflags = kn->kn_sfflags;
+		kev.data = kn->kn_id;		/* parent */
+		kev.udata = kn->kn_kevent.udata;/* preserve udata */
+		error = kqueue_register(kq, &kev, NULL, 0);
+		if (kn->kn_fop->f_event(kn, NOTE_FORK | pid))
+			KNOTE_ACTIVATE(kn, 0);
+		if (error)
+			kn->kn_fflags |= NOTE_TRACKERR;
+		KQ_LOCK(kq);
+		kn->kn_status &= ~KN_INFLUX;
+		KQ_UNLOCK_FLUX(kq);
+		list->kl_lock(list->kl_lockarg);
+	}
+	list->kl_unlock(list->kl_lockarg);
+}
+
+static int
+timertoticks(intptr_t data)
+{
+	struct timeval tv;
+	int tticks;
+
+	tv.tv_sec = data / 1000;
+	tv.tv_usec = (data % 1000) * 1000;
+	tticks = tvtohz(&tv);
+
+	return tticks;
+}
+
+/* XXX - move to kern_timeout.c? */
+static void
+filt_timerexpire(void *knx)
+{
+	struct knote *kn = knx;
+	struct callout *calloutp;
+
+	kn->kn_data++;
+	KNOTE_ACTIVATE(kn, 0);	/* XXX - handle locking */
+
+	if ((kn->kn_flags & EV_ONESHOT) != EV_ONESHOT) {
+		calloutp = (struct callout *)kn->kn_hook;
+		callout_reset_curcpu(calloutp, timertoticks(kn->kn_sdata),
+		    filt_timerexpire, kn);
+	}
+}
+
+/*
+ * data contains amount of time to sleep, in milliseconds
+ */
+/* XXX - move to kern_timeout.c? */
+static int
+filt_timerattach(struct knote *kn)
+{
+	struct callout *calloutp;
+
+	atomic_add_int(&kq_ncallouts, 1);
+
+	if (kq_ncallouts >= kq_calloutmax) {
+		atomic_add_int(&kq_ncallouts, -1);
+		return (ENOMEM);
+	}
+
+	kn->kn_flags |= EV_CLEAR;		/* automatically set */
+	kn->kn_status &= ~KN_DETACHED;		/* knlist_add usually sets it */
+	calloutp = malloc(sizeof(*calloutp), M_KQUEUE, M_WAITOK);
+	callout_init(calloutp, CALLOUT_MPSAFE);
+	kn->kn_hook = calloutp;
+	callout_reset_curcpu(calloutp, timertoticks(kn->kn_sdata),
+	    filt_timerexpire, kn);
+
+	return (0);
+}
+
+/* XXX - move to kern_timeout.c? */
+static void
+filt_timerdetach(struct knote *kn)
+{
+	struct callout *calloutp;
+
+	calloutp = (struct callout *)kn->kn_hook;
+	callout_drain(calloutp);
+	free(calloutp, M_KQUEUE);
+	atomic_add_int(&kq_ncallouts, -1);
+	kn->kn_status |= KN_DETACHED;	/* knlist_remove usually clears it */
+}
+
+/* XXX - move to kern_timeout.c? */
+static int
+filt_timer(struct knote *kn, long hint)
+{
+
+	return (kn->kn_data != 0);
+}
+
+static int
+filt_userattach(struct knote *kn)
+{
+
+	/* 
+	 * EVFILT_USER knotes are not attached to anything in the kernel.
+	 */ 
+	kn->kn_hook = NULL;
+	if (kn->kn_fflags & NOTE_TRIGGER)
+		kn->kn_hookid = 1;
+	else
+		kn->kn_hookid = 0;
+	return (0);
+}
+
+static void
+filt_userdetach(__unused struct knote *kn)
+{
+
+	/*
+	 * EVFILT_USER knotes are not attached to anything in the kernel.
+	 */
+}
+
+static int
+filt_user(struct knote *kn, __unused long hint)
+{
+
+	return (kn->kn_hookid);
+}
+
+static void
+filt_usertouch(struct knote *kn, struct kevent *kev, u_long type)
+{
+	u_int ffctrl;
+
+	switch (type) {
+	case EVENT_REGISTER:
+		if (kev->fflags & NOTE_TRIGGER)
+			kn->kn_hookid = 1;
+
+		ffctrl = kev->fflags & NOTE_FFCTRLMASK;
+		kev->fflags &= NOTE_FFLAGSMASK;
+		switch (ffctrl) {
+		case NOTE_FFNOP:
+			break;
+
+		case NOTE_FFAND:
+			kn->kn_sfflags &= kev->fflags;
+			break;
+
+		case NOTE_FFOR:
+			kn->kn_sfflags |= kev->fflags;
+			break;
+
+		case NOTE_FFCOPY:
+			kn->kn_sfflags = kev->fflags;
+			break;
+
+		default:
+			/* XXX Return error? */
+			break;
+		}
+		kn->kn_sdata = kev->data;
+		if (kev->flags & EV_CLEAR) {
+			kn->kn_hookid = 0;
+			kn->kn_data = 0;
+			kn->kn_fflags = 0;
+		}
+		break;
+
+        case EVENT_PROCESS:
+		*kev = kn->kn_kevent;
+		kev->fflags = kn->kn_sfflags;
+		kev->data = kn->kn_sdata;
+		if (kn->kn_flags & EV_CLEAR) {
+			kn->kn_hookid = 0;
+			kn->kn_data = 0;
+			kn->kn_fflags = 0;
+		}
+		break;
+
+	default:
+		panic("filt_usertouch() - invalid type (%ld)", type);
+		break;
+	}
+}
+
+int
+kqueue(struct thread *td, struct kqueue_args *uap)
+{
+	struct filedesc *fdp;
+	struct kqueue *kq;
+	struct file *fp;
+	int fd, error;
+
+	fdp = td->td_proc->p_fd;
+	error = falloc(td, &fp, &fd);
+	if (error)
+		goto done2;
+
+	/* An extra reference on `nfp' has been held for us by falloc(). */
+	kq = malloc(sizeof *kq, M_KQUEUE, M_WAITOK | M_ZERO);
+	mtx_init(&kq->kq_lock, "kqueue", NULL, MTX_DEF|MTX_DUPOK);
+	TAILQ_INIT(&kq->kq_head);
+	kq->kq_fdp = fdp;
+	knlist_init_mtx(&kq->kq_sel.si_note, &kq->kq_lock);
+	TASK_INIT(&kq->kq_task, 0, kqueue_task, kq);
+
+	FILEDESC_XLOCK(fdp);
+	SLIST_INSERT_HEAD(&fdp->fd_kqlist, kq, kq_list);
+	FILEDESC_XUNLOCK(fdp);
+
+	finit(fp, FREAD | FWRITE, DTYPE_KQUEUE, kq, &kqueueops);
+	fdrop(fp, td);
+
+	td->td_retval[0] = fd;
+done2:
+	return (error);
+}
+
+#ifndef _SYS_SYSPROTO_HH_
+struct kevent_args {
+	int	fd;
+	const struct kevent *changelist;
+	int	nchanges;
+	struct	kevent *eventlist;
+	int	nevents;
+	const struct timespec *timeout;
+};
+#endif
+int
+kevent(struct thread *td, struct kevent_args *uap)
+{
+	struct timespec ts, *tsp;
+	struct kevent_copyops k_ops = { uap,
+					kevent_copyout,
+					kevent_copyin};
+	int error;
+#ifdef KTRACE
+	struct uio ktruio;
+	struct iovec ktriov;
+	struct uio *ktruioin = NULL;
+	struct uio *ktruioout = NULL;
+#endif
+
+	if (uap->timeout != NULL) {
+		error = copyin(uap->timeout, &ts, sizeof(ts));
+		if (error)
+			return (error);
+		tsp = &ts;
+	} else
+		tsp = NULL;
+
+#ifdef KTRACE
+	if (KTRPOINT(td, KTR_GENIO)) {
+		ktriov.iov_base = uap->changelist;
+		ktriov.iov_len = uap->nchanges * sizeof(struct kevent);
+		ktruio = (struct uio){ .uio_iov = &ktriov, .uio_iovcnt = 1,
+		    .uio_segflg = UIO_USERSPACE, .uio_rw = UIO_READ,
+		    .uio_td = td };
+		ktruioin = cloneuio(&ktruio);
+		ktriov.iov_base = uap->eventlist;
+		ktriov.iov_len = uap->nevents * sizeof(struct kevent);
+		ktruioout = cloneuio(&ktruio);
+	}
+#endif
+
+	error = kern_kevent(td, uap->fd, uap->nchanges, uap->nevents,
+	    &k_ops, tsp);
+
+#ifdef KTRACE
+	if (ktruioin != NULL) {
+		ktruioin->uio_resid = uap->nchanges * sizeof(struct kevent);
+		ktrgenio(uap->fd, UIO_WRITE, ktruioin, 0);
+		ktruioout->uio_resid = td->td_retval[0] * sizeof(struct kevent);
+		ktrgenio(uap->fd, UIO_READ, ktruioout, error);
+	}
+#endif
+
+	return (error);
+}
+
+/*
+ * Copy 'count' items into the destination list pointed to by uap->eventlist.
+ */
+static int
+kevent_copyout(void *arg, struct kevent *kevp, int count)
+{
+	struct kevent_args *uap;
+	int error;
+
+	KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count));
+	uap = (struct kevent_args *)arg;
+
+	error = copyout(kevp, uap->eventlist, count * sizeof *kevp);
+	if (error == 0)
+		uap->eventlist += count;
+	return (error);
+}
+
+/*
+ * Copy 'count' items from the list pointed to by uap->changelist.
+ */
+static int
+kevent_copyin(void *arg, struct kevent *kevp, int count)
+{
+	struct kevent_args *uap;
+	int error;
+
+	KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count));
+	uap = (struct kevent_args *)arg;
+
+	error = copyin(uap->changelist, kevp, count * sizeof *kevp);
+	if (error == 0)
+		uap->changelist += count;
+	return (error);
+}
+
+int
+kern_kevent(struct thread *td, int fd, int nchanges, int nevents,
+    struct kevent_copyops *k_ops, const struct timespec *timeout)
+{
+	struct kevent keva[KQ_NEVENTS];
+	struct kevent *kevp, *changes;
+	struct kqueue *kq;
+	struct file *fp;
+	int i, n, nerrors, error;
+
+	if ((error = fget(td, fd, &fp)) != 0)
+		return (error);
+	if ((error = kqueue_acquire(fp, &kq)) != 0)
+		goto done_norel;
+
+	nerrors = 0;
+
+	while (nchanges > 0) {
+		n = nchanges > KQ_NEVENTS ? KQ_NEVENTS : nchanges;
+		error = k_ops->k_copyin(k_ops->arg, keva, n);
+		if (error)
+			goto done;
+		changes = keva;
+		for (i = 0; i < n; i++) {
+			kevp = &changes[i];
+			if (!kevp->filter)
+				continue;
+			kevp->flags &= ~EV_SYSFLAGS;
+			error = kqueue_register(kq, kevp, td, 1);
+			if (error || (kevp->flags & EV_RECEIPT)) {
+				if (nevents != 0) {
+					kevp->flags = EV_ERROR;
+					kevp->data = error;
+					(void) k_ops->k_copyout(k_ops->arg,
+					    kevp, 1);
+					nevents--;
+					nerrors++;
+				} else {
+					goto done;
+				}
+			}
+		}
+		nchanges -= n;
+	}
+	if (nerrors) {
+		td->td_retval[0] = nerrors;
+		error = 0;
+		goto done;
+	}
+
+	error = kqueue_scan(kq, nevents, k_ops, timeout, keva, td);
+done:
+	kqueue_release(kq, 0);
+done_norel:
+	fdrop(fp, td);
+	return (error);
+}
+
+int
+kqueue_add_filteropts(int filt, struct filterops *filtops)
+{
+	int error;
+
+	error = 0;
+	if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) {
+		printf(
+"trying to add a filterop that is out of range: %d is beyond %d\n",
+		    ~filt, EVFILT_SYSCOUNT);
+		return EINVAL;
+	}
+	mtx_lock(&filterops_lock);
+	if (sysfilt_ops[~filt].for_fop != &null_filtops &&
+	    sysfilt_ops[~filt].for_fop != NULL)
+		error = EEXIST;
+	else {
+		sysfilt_ops[~filt].for_fop = filtops;
+		sysfilt_ops[~filt].for_refcnt = 0;
+	}
+	mtx_unlock(&filterops_lock);
+
+	return (error);
+}
+
+int
+kqueue_del_filteropts(int filt)
+{
+	int error;
+
+	error = 0;
+	if (filt > 0 || filt + EVFILT_SYSCOUNT < 0)
+		return EINVAL;
+
+	mtx_lock(&filterops_lock);
+	if (sysfilt_ops[~filt].for_fop == &null_filtops ||
+	    sysfilt_ops[~filt].for_fop == NULL)
+		error = EINVAL;
+	else if (sysfilt_ops[~filt].for_refcnt != 0)
+		error = EBUSY;
+	else {
+		sysfilt_ops[~filt].for_fop = &null_filtops;
+		sysfilt_ops[~filt].for_refcnt = 0;
+	}
+	mtx_unlock(&filterops_lock);
+
+	return error;
+}
+
+static struct filterops *
+kqueue_fo_find(int filt)
+{
+
+	if (filt > 0 || filt + EVFILT_SYSCOUNT < 0)
+		return NULL;
+
+	mtx_lock(&filterops_lock);
+	sysfilt_ops[~filt].for_refcnt++;
+	if (sysfilt_ops[~filt].for_fop == NULL)
+		sysfilt_ops[~filt].for_fop = &null_filtops;
+	mtx_unlock(&filterops_lock);
+
+	return sysfilt_ops[~filt].for_fop;
+}
+
+static void
+kqueue_fo_release(int filt)
+{
+
+	if (filt > 0 || filt + EVFILT_SYSCOUNT < 0)
+		return;
+
+	mtx_lock(&filterops_lock);
+	KASSERT(sysfilt_ops[~filt].for_refcnt > 0,
+	    ("filter object refcount not valid on release"));
+	sysfilt_ops[~filt].for_refcnt--;
+	mtx_unlock(&filterops_lock);
+}
+
+/*
+ * A ref to kq (obtained via kqueue_acquire) must be held.  waitok will
+ * influence if memory allocation should wait.  Make sure it is 0 if you
+ * hold any mutexes.
+ */
+static int
+kqueue_register(struct kqueue *kq, struct kevent *kev, struct thread *td, int waitok)
+{
+	struct filterops *fops;
+	struct file *fp;
+	struct knote *kn, *tkn;
+	int error, filt, event;
+	int haskqglobal;
+
+	fp = NULL;
+	kn = NULL;
+	error = 0;
+	haskqglobal = 0;
+
+	filt = kev->filter;
+	fops = kqueue_fo_find(filt);
+	if (fops == NULL)
+		return EINVAL;
+
+	tkn = knote_alloc(waitok);		/* prevent waiting with locks */
+
+findkn:
+	if (fops->f_isfd) {
+		KASSERT(td != NULL, ("td is NULL"));
+		error = fget(td, kev->ident, &fp);
+		if (error)
+			goto done;
+
+		if ((kev->flags & EV_ADD) == EV_ADD && kqueue_expand(kq, fops,
+		    kev->ident, 0) != 0) {
+			/* try again */
+			fdrop(fp, td);
+			fp = NULL;
+			error = kqueue_expand(kq, fops, kev->ident, waitok);
+			if (error)
+				goto done;
+			goto findkn;
+		}
+
+		if (fp->f_type == DTYPE_KQUEUE) {
+			/*
+			 * if we add some inteligence about what we are doing,
+			 * we should be able to support events on ourselves.
+			 * We need to know when we are doing this to prevent
+			 * getting both the knlist lock and the kq lock since
+			 * they are the same thing.
+			 */
+			if (fp->f_data == kq) {
+				error = EINVAL;
+				goto done;
+			}
+
+			KQ_GLOBAL_LOCK(&kq_global, haskqglobal);
+		}
+
+		KQ_LOCK(kq);
+		if (kev->ident < kq->kq_knlistsize) {
+			SLIST_FOREACH(kn, &kq->kq_knlist[kev->ident], kn_link)
+				if (kev->filter == kn->kn_filter)
+					break;
+		}
+	} else {
+		if ((kev->flags & EV_ADD) == EV_ADD)
+			kqueue_expand(kq, fops, kev->ident, waitok);
+
+		KQ_LOCK(kq);
+		if (kq->kq_knhashmask != 0) {
+			struct klist *list;
+
+			list = &kq->kq_knhash[
+			    KN_HASH((u_long)kev->ident, kq->kq_knhashmask)];
+			SLIST_FOREACH(kn, list, kn_link)
+				if (kev->ident == kn->kn_id &&
+				    kev->filter == kn->kn_filter)
+					break;
+		}
+	}
+
+	/* knote is in the process of changing, wait for it to stablize. */
+	if (kn != NULL && (kn->kn_status & KN_INFLUX) == KN_INFLUX) {
+		KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal);
+		kq->kq_state |= KQ_FLUXWAIT;
+		msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqflxwt", 0);
+		if (fp != NULL) {
+			fdrop(fp, td);
+			fp = NULL;
+		}
+		goto findkn;
+	}
+
+	/*
+	 * kn now contains the matching knote, or NULL if no match
+	 */
+	if (kn == NULL) {
+		if (kev->flags & EV_ADD) {
+			kn = tkn;
+			tkn = NULL;
+			if (kn == NULL) {
+				KQ_UNLOCK(kq);
+				error = ENOMEM;
+				goto done;
+			}
+			kn->kn_fp = fp;
+			kn->kn_kq = kq;
+			kn->kn_fop = fops;
+			/*
+			 * apply reference counts to knote structure, and
+			 * do not release it at the end of this routine.
+			 */
+			fops = NULL;
+			fp = NULL;
+
+			kn->kn_sfflags = kev->fflags;
+			kn->kn_sdata = kev->data;
+			kev->fflags = 0;
+			kev->data = 0;
+			kn->kn_kevent = *kev;
+			kn->kn_kevent.flags &= ~(EV_ADD | EV_DELETE |
+			    EV_ENABLE | EV_DISABLE);
+			kn->kn_status = KN_INFLUX|KN_DETACHED;
+
+			error = knote_attach(kn, kq);
+			KQ_UNLOCK(kq);
+			if (error != 0) {
+				tkn = kn;
+				goto done;
+			}
+
+			if ((error = kn->kn_fop->f_attach(kn)) != 0) {
+				knote_drop(kn, td);
+				goto done;
+			}
+			KN_LIST_LOCK(kn);
+			goto done_ev_add;
+		} else {
+			/* No matching knote and the EV_ADD flag is not set. */
+			KQ_UNLOCK(kq);
+			error = ENOENT;
+			goto done;
+		}
+	}
+	
+	if (kev->flags & EV_DELETE) {
+		kn->kn_status |= KN_INFLUX;
+		KQ_UNLOCK(kq);
+		if (!(kn->kn_status & KN_DETACHED))
+			kn->kn_fop->f_detach(kn);
+		knote_drop(kn, td);
+		goto done;
+	}
+
+	/*
+	 * The user may change some filter values after the initial EV_ADD,
+	 * but doing so will not reset any filter which has already been
+	 * triggered.
+	 */
+	kn->kn_status |= KN_INFLUX;
+	KQ_UNLOCK(kq);
+	KN_LIST_LOCK(kn);
+	kn->kn_kevent.udata = kev->udata;
+	if (!fops->f_isfd && fops->f_touch != NULL) {
+		fops->f_touch(kn, kev, EVENT_REGISTER);
+	} else {
+		kn->kn_sfflags = kev->fflags;
+		kn->kn_sdata = kev->data;
+	}
+
+	/*
+	 * We can get here with kn->kn_knlist == NULL.  This can happen when
+	 * the initial attach event decides that the event is "completed" 
+	 * already.  i.e. filt_procattach is called on a zombie process.  It
+	 * will call filt_proc which will remove it from the list, and NULL
+	 * kn_knlist.
+	 */
+done_ev_add:
+	event = kn->kn_fop->f_event(kn, 0);
+	KQ_LOCK(kq);
+	if (event)
+		KNOTE_ACTIVATE(kn, 1);
+	kn->kn_status &= ~KN_INFLUX;
+	KN_LIST_UNLOCK(kn);
+
+	if ((kev->flags & EV_DISABLE) &&
+	    ((kn->kn_status & KN_DISABLED) == 0)) {
+		kn->kn_status |= KN_DISABLED;
+	}
+
+	if ((kev->flags & EV_ENABLE) && (kn->kn_status & KN_DISABLED)) {
+		kn->kn_status &= ~KN_DISABLED;
+		if ((kn->kn_status & KN_ACTIVE) &&
+		    ((kn->kn_status & KN_QUEUED) == 0))
+			knote_enqueue(kn);
+	}
+	KQ_UNLOCK_FLUX(kq);
+
+done:
+	KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal);
+	if (fp != NULL)
+		fdrop(fp, td);
+	if (tkn != NULL)
+		knote_free(tkn);
+	if (fops != NULL)
+		kqueue_fo_release(filt);
+	return (error);
+}
+
+static int
+kqueue_acquire(struct file *fp, struct kqueue **kqp)
+{
+	int error;
+	struct kqueue *kq;
+
+	error = 0;
+
+	kq = fp->f_data;
+	if (fp->f_type != DTYPE_KQUEUE || kq == NULL)
+		return (EBADF);
+	*kqp = kq;
+	KQ_LOCK(kq);
+	if ((kq->kq_state & KQ_CLOSING) == KQ_CLOSING) {
+		KQ_UNLOCK(kq);
+		return (EBADF);
+	}
+	kq->kq_refcnt++;
+	KQ_UNLOCK(kq);
+
+	return error;
+}
+
+static void
+kqueue_release(struct kqueue *kq, int locked)
+{
+	if (locked)
+		KQ_OWNED(kq);
+	else
+		KQ_LOCK(kq);
+	kq->kq_refcnt--;
+	if (kq->kq_refcnt == 1)
+		wakeup(&kq->kq_refcnt);
+	if (!locked)
+		KQ_UNLOCK(kq);
+}
+
+static void
+kqueue_schedtask(struct kqueue *kq)
+{
+
+	KQ_OWNED(kq);
+	KASSERT(((kq->kq_state & KQ_TASKDRAIN) != KQ_TASKDRAIN),
+	    ("scheduling kqueue task while draining"));
+
+	if ((kq->kq_state & KQ_TASKSCHED) != KQ_TASKSCHED) {
+		taskqueue_enqueue(taskqueue_kqueue, &kq->kq_task);
+		kq->kq_state |= KQ_TASKSCHED;
+	}
+}
+
+/*
+ * Expand the kq to make sure we have storage for fops/ident pair.
+ *
+ * Return 0 on success (or no work necessary), return errno on failure.
+ *
+ * Not calling hashinit w/ waitok (proper malloc flag) should be safe.
+ * If kqueue_register is called from a non-fd context, there usually/should
+ * be no locks held.
+ */
+static int
+kqueue_expand(struct kqueue *kq, struct filterops *fops, uintptr_t ident,
+	int waitok)
+{
+	struct klist *list, *tmp_knhash, *to_free;
+	u_long tmp_knhashmask;
+	int size;
+	int fd;
+	int mflag = waitok ? M_WAITOK : M_NOWAIT;
+
+	KQ_NOTOWNED(kq);
+
+	to_free = NULL;
+	if (fops->f_isfd) {
+		fd = ident;
+		if (kq->kq_knlistsize <= fd) {
+			size = kq->kq_knlistsize;
+			while (size <= fd)
+				size += KQEXTENT;
+			list = malloc(size * sizeof list, M_KQUEUE, mflag);
+			if (list == NULL)
+				return ENOMEM;
+			KQ_LOCK(kq);
+			if (kq->kq_knlistsize > fd) {
+				to_free = list;
+				list = NULL;
+			} else {
+				if (kq->kq_knlist != NULL) {
+					bcopy(kq->kq_knlist, list,
+					    kq->kq_knlistsize * sizeof list);
+					to_free = kq->kq_knlist;
+					kq->kq_knlist = NULL;
+				}
+				bzero((caddr_t)list +
+				    kq->kq_knlistsize * sizeof list,
+				    (size - kq->kq_knlistsize) * sizeof list);
+				kq->kq_knlistsize = size;
+				kq->kq_knlist = list;
+			}
+			KQ_UNLOCK(kq);
+		}
+	} else {
+		if (kq->kq_knhashmask == 0) {
+			tmp_knhash = hashinit(KN_HASHSIZE, M_KQUEUE,
+			    &tmp_knhashmask);
+			if (tmp_knhash == NULL)
+				return ENOMEM;
+			KQ_LOCK(kq);
+			if (kq->kq_knhashmask == 0) {
+				kq->kq_knhash = tmp_knhash;
+				kq->kq_knhashmask = tmp_knhashmask;
+			} else {
+				to_free = tmp_knhash;
+			}
+			KQ_UNLOCK(kq);
+		}
+	}
+	free(to_free, M_KQUEUE);
+
+	KQ_NOTOWNED(kq);
+	return 0;
+}
+
+static void
+kqueue_task(void *arg, int pending)
+{
+	struct kqueue *kq;
+	int haskqglobal;
+
+	haskqglobal = 0;
+	kq = arg;
+
+	KQ_GLOBAL_LOCK(&kq_global, haskqglobal);
+	KQ_LOCK(kq);
+
+	KNOTE_LOCKED(&kq->kq_sel.si_note, 0);
+
+	kq->kq_state &= ~KQ_TASKSCHED;
+	if ((kq->kq_state & KQ_TASKDRAIN) == KQ_TASKDRAIN) {
+		wakeup(&kq->kq_state);
+	}
+	KQ_UNLOCK(kq);
+	KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal);
+}
+
+/*
+ * Scan, update kn_data (if not ONESHOT), and copyout triggered events.
+ * We treat KN_MARKER knotes as if they are INFLUX.
+ */
+static int
+kqueue_scan(struct kqueue *kq, int maxevents, struct kevent_copyops *k_ops,
+    const struct timespec *tsp, struct kevent *keva, struct thread *td)
+{
+	struct kevent *kevp;
+	struct timeval atv, rtv, ttv;
+	struct knote *kn, *marker;
+	int count, timeout, nkev, error, influx;
+	int haskqglobal, touch;
+
+	count = maxevents;
+	nkev = 0;
+	error = 0;
+	haskqglobal = 0;
+
+	if (maxevents == 0)
+		goto done_nl;
+
+	if (tsp != NULL) {
+		TIMESPEC_TO_TIMEVAL(&atv, tsp);
+		if (itimerfix(&atv)) {
+			error = EINVAL;
+			goto done_nl;
+		}
+		if (tsp->tv_sec == 0 && tsp->tv_nsec == 0)
+			timeout = -1;
+		else
+			timeout = atv.tv_sec > 24 * 60 * 60 ?
+			    24 * 60 * 60 * hz : tvtohz(&atv);
+		getmicrouptime(&rtv);
+		timevaladd(&atv, &rtv);
+	} else {
+		atv.tv_sec = 0;
+		atv.tv_usec = 0;
+		timeout = 0;
+	}
+	marker = knote_alloc(1);
+	if (marker == NULL) {
+		error = ENOMEM;
+		goto done_nl;
+	}
+	marker->kn_status = KN_MARKER;
+	KQ_LOCK(kq);
+	goto start;
+
+retry:
+	if (atv.tv_sec || atv.tv_usec) {
+		getmicrouptime(&rtv);
+		if (timevalcmp(&rtv, &atv, >=))
+			goto done;
+		ttv = atv;
+		timevalsub(&ttv, &rtv);
+		timeout = ttv.tv_sec > 24 * 60 * 60 ?
+			24 * 60 * 60 * hz : tvtohz(&ttv);
+	}
+
+start:
+	kevp = keva;
+	if (kq->kq_count == 0) {
+		if (timeout < 0) {
+			error = EWOULDBLOCK;
+		} else {
+			kq->kq_state |= KQ_SLEEP;
+			error = msleep(kq, &kq->kq_lock, PSOCK | PCATCH,
+			    "kqread", timeout);
+		}
+		if (error == 0)
+			goto retry;
+		/* don't restart after signals... */
+		if (error == ERESTART)
+			error = EINTR;
+		else if (error == EWOULDBLOCK)
+			error = 0;
+		goto done;
+	}
+
+	TAILQ_INSERT_TAIL(&kq->kq_head, marker, kn_tqe);
+	influx = 0;
+	while (count) {
+		KQ_OWNED(kq);
+		kn = TAILQ_FIRST(&kq->kq_head);
+
+		if ((kn->kn_status == KN_MARKER && kn != marker) ||
+		    (kn->kn_status & KN_INFLUX) == KN_INFLUX) {
+			if (influx) {
+				influx = 0;
+				KQ_FLUX_WAKEUP(kq);
+			}
+			kq->kq_state |= KQ_FLUXWAIT;
+			error = msleep(kq, &kq->kq_lock, PSOCK,
+			    "kqflxwt", 0);
+			continue;
+		}
+
+		TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe);
+		if ((kn->kn_status & KN_DISABLED) == KN_DISABLED) {
+			kn->kn_status &= ~KN_QUEUED;
+			kq->kq_count--;
+			continue;
+		}
+		if (kn == marker) {
+			KQ_FLUX_WAKEUP(kq);
+			if (count == maxevents)
+				goto retry;
+			goto done;
+		}
+		KASSERT((kn->kn_status & KN_INFLUX) == 0,
+		    ("KN_INFLUX set when not suppose to be"));
+
+		if ((kn->kn_flags & EV_ONESHOT) == EV_ONESHOT) {
+			kn->kn_status &= ~KN_QUEUED;
+			kn->kn_status |= KN_INFLUX;
+			kq->kq_count--;
+			KQ_UNLOCK(kq);
+			/*
+			 * We don't need to lock the list since we've marked
+			 * it _INFLUX.
+			 */
+			*kevp = kn->kn_kevent;
+			if (!(kn->kn_status & KN_DETACHED))
+				kn->kn_fop->f_detach(kn);
+			knote_drop(kn, td);
+			KQ_LOCK(kq);
+			kn = NULL;
+		} else {
+			kn->kn_status |= KN_INFLUX;
+			KQ_UNLOCK(kq);
+			if ((kn->kn_status & KN_KQUEUE) == KN_KQUEUE)
+				KQ_GLOBAL_LOCK(&kq_global, haskqglobal);
+			KN_LIST_LOCK(kn);
+			if (kn->kn_fop->f_event(kn, 0) == 0) {
+				KQ_LOCK(kq);
+				KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal);
+				kn->kn_status &=
+				    ~(KN_QUEUED | KN_ACTIVE | KN_INFLUX);
+				kq->kq_count--;
+				KN_LIST_UNLOCK(kn);
+				influx = 1;
+				continue;
+			}
+			touch = (!kn->kn_fop->f_isfd &&
+			    kn->kn_fop->f_touch != NULL);
+			if (touch)
+				kn->kn_fop->f_touch(kn, kevp, EVENT_PROCESS);
+			else
+				*kevp = kn->kn_kevent;
+			KQ_LOCK(kq);
+			KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal);
+			if (kn->kn_flags & (EV_CLEAR |  EV_DISPATCH)) {
+				/* 
+				 * Manually clear knotes who weren't 
+				 * 'touch'ed.
+				 */
+				if (touch == 0 && kn->kn_flags & EV_CLEAR) {
+					kn->kn_data = 0;
+					kn->kn_fflags = 0;
+				}
+				if (kn->kn_flags & EV_DISPATCH)
+					kn->kn_status |= KN_DISABLED;
+				kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE);
+				kq->kq_count--;
+			} else
+				TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe);
+			
+			kn->kn_status &= ~(KN_INFLUX);
+			KN_LIST_UNLOCK(kn);
+			influx = 1;
+		}
+
+		/* we are returning a copy to the user */
+		kevp++;
+		nkev++;
+		count--;
+
+		if (nkev == KQ_NEVENTS) {
+			influx = 0;
+			KQ_UNLOCK_FLUX(kq);
+			error = k_ops->k_copyout(k_ops->arg, keva, nkev);
+			nkev = 0;
+			kevp = keva;
+			KQ_LOCK(kq);
+			if (error)
+				break;
+		}
+	}
+	TAILQ_REMOVE(&kq->kq_head, marker, kn_tqe);
+done:
+	KQ_OWNED(kq);
+	KQ_UNLOCK_FLUX(kq);
+	knote_free(marker);
+done_nl:
+	KQ_NOTOWNED(kq);
+	if (nkev != 0)
+		error = k_ops->k_copyout(k_ops->arg, keva, nkev);
+	td->td_retval[0] = maxevents - count;
+	return (error);
+}
+
+/*
+ * XXX
+ * This could be expanded to call kqueue_scan, if desired.
+ */
+/*ARGSUSED*/
+static int
+kqueue_read(struct file *fp, struct uio *uio, struct ucred *active_cred,
+	int flags, struct thread *td)
+{
+	return (ENXIO);
+}
+
+/*ARGSUSED*/
+static int
+kqueue_write(struct file *fp, struct uio *uio, struct ucred *active_cred,
+	 int flags, struct thread *td)
+{
+	return (ENXIO);
+}
+
+/*ARGSUSED*/
+static int
+kqueue_truncate(struct file *fp, off_t length, struct ucred *active_cred,
+	struct thread *td)
+{
+
+	return (EINVAL);
+}
+
+/*ARGSUSED*/
+static int
+kqueue_ioctl(struct file *fp, u_long cmd, void *data,
+	struct ucred *active_cred, struct thread *td)
+{
+	/*
+	 * Enabling sigio causes two major problems:
+	 * 1) infinite recursion:
+	 * Synopsys: kevent is being used to track signals and have FIOASYNC
+	 * set.  On receipt of a signal this will cause a kqueue to recurse
+	 * into itself over and over.  Sending the sigio causes the kqueue
+	 * to become ready, which in turn posts sigio again, forever.
+	 * Solution: this can be solved by setting a flag in the kqueue that
+	 * we have a SIGIO in progress.
+	 * 2) locking problems:
+	 * Synopsys: Kqueue is a leaf subsystem, but adding signalling puts
+	 * us above the proc and pgrp locks.
+	 * Solution: Post a signal using an async mechanism, being sure to
+	 * record a generation count in the delivery so that we do not deliver
+	 * a signal to the wrong process.
+	 *
+	 * Note, these two mechanisms are somewhat mutually exclusive!
+	 */
+#if 0
+	struct kqueue *kq;
+
+	kq = fp->f_data;
+	switch (cmd) {
+	case FIOASYNC:
+		if (*(int *)data) {
+			kq->kq_state |= KQ_ASYNC;
+		} else {
+			kq->kq_state &= ~KQ_ASYNC;
+		}
+		return (0);
+
+	case FIOSETOWN:
+		return (fsetown(*(int *)data, &kq->kq_sigio));
+
+	case FIOGETOWN:
+		*(int *)data = fgetown(&kq->kq_sigio);
+		return (0);
+	}
+#endif
+
+	return (ENOTTY);
+}
+
+/*ARGSUSED*/
+static int
+kqueue_poll(struct file *fp, int events, struct ucred *active_cred,
+	struct thread *td)
+{
+	struct kqueue *kq;
+	int revents = 0;
+	int error;
+
+	if ((error = kqueue_acquire(fp, &kq)))
+		return POLLERR;
+
+	KQ_LOCK(kq);
+	if (events & (POLLIN | POLLRDNORM)) {
+		if (kq->kq_count) {
+			revents |= events & (POLLIN | POLLRDNORM);
+		} else {
+			selrecord(td, &kq->kq_sel);
+			if (SEL_WAITING(&kq->kq_sel))
+				kq->kq_state |= KQ_SEL;
+		}
+	}
+	kqueue_release(kq, 1);
+	KQ_UNLOCK(kq);
+	return (revents);
+}
+
+/*ARGSUSED*/
+static int
+kqueue_stat(struct file *fp, struct stat *st, struct ucred *active_cred,
+	struct thread *td)
+{
+
+	bzero((void *)st, sizeof *st);
+	/*
+	 * We no longer return kq_count because the unlocked value is useless.
+	 * If you spent all this time getting the count, why not spend your
+	 * syscall better by calling kevent?
+	 *
+	 * XXX - This is needed for libc_r.
+	 */
+	st->st_mode = S_IFIFO;
+	return (0);
+}
+
+/*ARGSUSED*/
+static int
+kqueue_close(struct file *fp, struct thread *td)
+{
+	struct kqueue *kq = fp->f_data;
+	struct filedesc *fdp;
+	struct knote *kn;
+	int i;
+	int error;
+
+	if ((error = kqueue_acquire(fp, &kq)))
+		return error;
+
+	KQ_LOCK(kq);
+
+	KASSERT((kq->kq_state & KQ_CLOSING) != KQ_CLOSING,
+	    ("kqueue already closing"));
+	kq->kq_state |= KQ_CLOSING;
+	if (kq->kq_refcnt > 1)
+		msleep(&kq->kq_refcnt, &kq->kq_lock, PSOCK, "kqclose", 0);
+
+	KASSERT(kq->kq_refcnt == 1, ("other refs are out there!"));
+	fdp = kq->kq_fdp;
+
+	KASSERT(knlist_empty(&kq->kq_sel.si_note),
+	    ("kqueue's knlist not empty"));
+
+	for (i = 0; i < kq->kq_knlistsize; i++) {
+		while ((kn = SLIST_FIRST(&kq->kq_knlist[i])) != NULL) {
+			if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) {
+				kq->kq_state |= KQ_FLUXWAIT;
+				msleep(kq, &kq->kq_lock, PSOCK, "kqclo1", 0);
+				continue;
+			}
+			kn->kn_status |= KN_INFLUX;
+			KQ_UNLOCK(kq);
+			if (!(kn->kn_status & KN_DETACHED))
+				kn->kn_fop->f_detach(kn);
+			knote_drop(kn, td);
+			KQ_LOCK(kq);
+		}
+	}
+	if (kq->kq_knhashmask != 0) {
+		for (i = 0; i <= kq->kq_knhashmask; i++) {
+			while ((kn = SLIST_FIRST(&kq->kq_knhash[i])) != NULL) {
+				if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) {
+					kq->kq_state |= KQ_FLUXWAIT;
+					msleep(kq, &kq->kq_lock, PSOCK,
+					       "kqclo2", 0);
+					continue;
+				}
+				kn->kn_status |= KN_INFLUX;
+				KQ_UNLOCK(kq);
+				if (!(kn->kn_status & KN_DETACHED))
+					kn->kn_fop->f_detach(kn);
+				knote_drop(kn, td);
+				KQ_LOCK(kq);
+			}
+		}
+	}
+
+	if ((kq->kq_state & KQ_TASKSCHED) == KQ_TASKSCHED) {
+		kq->kq_state |= KQ_TASKDRAIN;
+		msleep(&kq->kq_state, &kq->kq_lock, PSOCK, "kqtqdr", 0);
+	}
+
+	if ((kq->kq_state & KQ_SEL) == KQ_SEL) {
+		selwakeuppri(&kq->kq_sel, PSOCK);
+		if (!SEL_WAITING(&kq->kq_sel))
+			kq->kq_state &= ~KQ_SEL;
+	}
+
+	KQ_UNLOCK(kq);
+
+	FILEDESC_XLOCK(fdp);
+	SLIST_REMOVE(&fdp->fd_kqlist, kq, kqueue, kq_list);
+	FILEDESC_XUNLOCK(fdp);
+
+	knlist_destroy(&kq->kq_sel.si_note);
+	mtx_destroy(&kq->kq_lock);
+	kq->kq_fdp = NULL;
+
+	if (kq->kq_knhash != NULL)
+		free(kq->kq_knhash, M_KQUEUE);
+	if (kq->kq_knlist != NULL)
+		free(kq->kq_knlist, M_KQUEUE);
+
+	funsetown(&kq->kq_sigio);
+	free(kq, M_KQUEUE);
+	fp->f_data = NULL;
+
+	return (0);
+}
+
+static void
+kqueue_wakeup(struct kqueue *kq)
+{
+	KQ_OWNED(kq);
+
+	if ((kq->kq_state & KQ_SLEEP) == KQ_SLEEP) {
+		kq->kq_state &= ~KQ_SLEEP;
+		wakeup(kq);
+	}
+	if ((kq->kq_state & KQ_SEL) == KQ_SEL) {
+		selwakeuppri(&kq->kq_sel, PSOCK);
+		if (!SEL_WAITING(&kq->kq_sel))
+			kq->kq_state &= ~KQ_SEL;
+	}
+	if (!knlist_empty(&kq->kq_sel.si_note))
+		kqueue_schedtask(kq);
+	if ((kq->kq_state & KQ_ASYNC) == KQ_ASYNC) {
+		pgsigio(&kq->kq_sigio, SIGIO, 0);
+	}
+}
+#endif /* __rtems__ */
+
+/*
+ * Walk down a list of knotes, activating them if their event has triggered.
+ *
+ * There is a possibility to optimize in the case of one kq watching another.
+ * Instead of scheduling a task to wake it up, you could pass enough state
+ * down the chain to make up the parent kqueue.  Make this code functional
+ * first.
+ */
+void
+knote(struct knlist *list, long hint, int lockflags)
+{
+	struct kqueue *kq;
+	struct knote *kn;
+	int error;
+
+	if (list == NULL)
+		return;
+
+	KNL_ASSERT_LOCK(list, lockflags & KNF_LISTLOCKED);
+
+	if ((lockflags & KNF_LISTLOCKED) == 0)
+		list->kl_lock(list->kl_lockarg); 
+
+	/*
+	 * If we unlock the list lock (and set KN_INFLUX), we can eliminate
+	 * the kqueue scheduling, but this will introduce four
+	 * lock/unlock's for each knote to test.  If we do, continue to use
+	 * SLIST_FOREACH, SLIST_FOREACH_SAFE is not safe in our case, it is
+	 * only safe if you want to remove the current item, which we are
+	 * not doing.
+	 */
+	SLIST_FOREACH(kn, &list->kl_list, kn_selnext) {
+		kq = kn->kn_kq;
+		if ((kn->kn_status & KN_INFLUX) != KN_INFLUX) {
+			KQ_LOCK(kq);
+			if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) {
+				KQ_UNLOCK(kq);
+			} else if ((lockflags & KNF_NOKQLOCK) != 0) {
+				kn->kn_status |= KN_INFLUX;
+				KQ_UNLOCK(kq);
+				error = kn->kn_fop->f_event(kn, hint);
+				KQ_LOCK(kq);
+				kn->kn_status &= ~KN_INFLUX;
+				if (error)
+					KNOTE_ACTIVATE(kn, 1);
+				KQ_UNLOCK_FLUX(kq);
+			} else {
+				kn->kn_status |= KN_HASKQLOCK;
+				if (kn->kn_fop->f_event(kn, hint))
+					KNOTE_ACTIVATE(kn, 1);
+				kn->kn_status &= ~KN_HASKQLOCK;
+				KQ_UNLOCK(kq);
+			}
+		}
+		kq = NULL;
+	}
+	if ((lockflags & KNF_LISTLOCKED) == 0)
+		list->kl_unlock(list->kl_lockarg); 
+}
+
+/*
+ * add a knote to a knlist
+ */
+void
+knlist_add(struct knlist *knl, struct knote *kn, int islocked)
+{
+	KNL_ASSERT_LOCK(knl, islocked);
+	KQ_NOTOWNED(kn->kn_kq);
+	KASSERT((kn->kn_status & (KN_INFLUX|KN_DETACHED)) ==
+	    (KN_INFLUX|KN_DETACHED), ("knote not KN_INFLUX and KN_DETACHED"));
+	if (!islocked)
+		knl->kl_lock(knl->kl_lockarg);
+	SLIST_INSERT_HEAD(&knl->kl_list, kn, kn_selnext);
+	if (!islocked)
+		knl->kl_unlock(knl->kl_lockarg);
+	KQ_LOCK(kn->kn_kq);
+	kn->kn_knlist = knl;
+	kn->kn_status &= ~KN_DETACHED;
+	KQ_UNLOCK(kn->kn_kq);
+}
+
+static void
+knlist_remove_kq(struct knlist *knl, struct knote *kn, int knlislocked, int kqislocked)
+{
+	KASSERT(!(!!kqislocked && !knlislocked), ("kq locked w/o knl locked"));
+	KNL_ASSERT_LOCK(knl, knlislocked);
+	mtx_assert(&kn->kn_kq->kq_lock, kqislocked ? MA_OWNED : MA_NOTOWNED);
+	if (!kqislocked)
+		KASSERT((kn->kn_status & (KN_INFLUX|KN_DETACHED)) == KN_INFLUX,
+    ("knlist_remove called w/o knote being KN_INFLUX or already removed"));
+	if (!knlislocked)
+		knl->kl_lock(knl->kl_lockarg);
+	SLIST_REMOVE(&knl->kl_list, kn, knote, kn_selnext);
+	kn->kn_knlist = NULL;
+	if (!knlislocked)
+		knl->kl_unlock(knl->kl_lockarg);
+	if (!kqislocked)
+		KQ_LOCK(kn->kn_kq);
+	kn->kn_status |= KN_DETACHED;
+	if (!kqislocked)
+		KQ_UNLOCK(kn->kn_kq);
+}
+
+/*
+ * remove all knotes from a specified klist
+ */
+void
+knlist_remove(struct knlist *knl, struct knote *kn, int islocked)
+{
+
+	knlist_remove_kq(knl, kn, islocked, 0);
+}
+
+#ifndef __rtems__
+/*
+ * remove knote from a specified klist while in f_event handler.
+ */
+void
+knlist_remove_inevent(struct knlist *knl, struct knote *kn)
+{
+
+	knlist_remove_kq(knl, kn, 1,
+	    (kn->kn_status & KN_HASKQLOCK) == KN_HASKQLOCK);
+}
+#endif /* __rtems__ */
+
+int
+knlist_empty(struct knlist *knl)
+{
+	KNL_ASSERT_LOCKED(knl);
+	return SLIST_EMPTY(&knl->kl_list);
+}
+
+static struct mtx	knlist_lock;
+MTX_SYSINIT(knlist_lock, &knlist_lock, "knlist lock for lockless objects",
+	MTX_DEF);
+static void knlist_mtx_lock(void *arg);
+static void knlist_mtx_unlock(void *arg);
+
+static void
+knlist_mtx_lock(void *arg)
+{
+	mtx_lock((struct mtx *)arg);
+}
+
+static void
+knlist_mtx_unlock(void *arg)
+{
+	mtx_unlock((struct mtx *)arg);
+}
+
+static void
+knlist_mtx_assert_locked(void *arg)
+{
+	mtx_assert((struct mtx *)arg, MA_OWNED);
+}
+
+static void
+knlist_mtx_assert_unlocked(void *arg)
+{
+	mtx_assert((struct mtx *)arg, MA_NOTOWNED);
+}
+
+void
+knlist_init(struct knlist *knl, void *lock, void (*kl_lock)(void *),
+    void (*kl_unlock)(void *),
+    void (*kl_assert_locked)(void *), void (*kl_assert_unlocked)(void *))
+{
+
+	if (lock == NULL)
+		knl->kl_lockarg = &knlist_lock;
+	else
+		knl->kl_lockarg = lock;
+
+	if (kl_lock == NULL)
+		knl->kl_lock = knlist_mtx_lock;
+	else
+		knl->kl_lock = kl_lock;
+	if (kl_unlock == NULL)
+		knl->kl_unlock = knlist_mtx_unlock;
+	else
+		knl->kl_unlock = kl_unlock;
+	if (kl_assert_locked == NULL)
+		knl->kl_assert_locked = knlist_mtx_assert_locked;
+	else
+		knl->kl_assert_locked = kl_assert_locked;
+	if (kl_assert_unlocked == NULL)
+		knl->kl_assert_unlocked = knlist_mtx_assert_unlocked;
+	else
+		knl->kl_assert_unlocked = kl_assert_unlocked;
+
+	SLIST_INIT(&knl->kl_list);
+}
+
+void
+knlist_init_mtx(struct knlist *knl, struct mtx *lock)
+{
+
+	knlist_init(knl, lock, NULL, NULL, NULL, NULL);
+}
+
+void
+knlist_destroy(struct knlist *knl)
+{
+
+#ifdef INVARIANTS
+	/*
+	 * if we run across this error, we need to find the offending
+	 * driver and have it call knlist_clear.
+	 */
+	if (!SLIST_EMPTY(&knl->kl_list))
+		printf("WARNING: destroying knlist w/ knotes on it!\n");
+#endif
+
+	knl->kl_lockarg = knl->kl_lock = knl->kl_unlock = NULL;
+	SLIST_INIT(&knl->kl_list);
+}
+
+#ifndef __rtems__
+/*
+ * Even if we are locked, we may need to drop the lock to allow any influx
+ * knotes time to "settle".
+ */
+void
+knlist_cleardel(struct knlist *knl, struct thread *td, int islocked, int killkn)
+{
+	struct knote *kn, *kn2;
+	struct kqueue *kq;
+
+	if (islocked)
+		KNL_ASSERT_LOCKED(knl);
+	else {
+		KNL_ASSERT_UNLOCKED(knl);
+again:		/* need to reacquire lock since we have dropped it */
+		knl->kl_lock(knl->kl_lockarg);
+	}
+
+	SLIST_FOREACH_SAFE(kn, &knl->kl_list, kn_selnext, kn2) {
+		kq = kn->kn_kq;
+		KQ_LOCK(kq);
+		if ((kn->kn_status & KN_INFLUX)) {
+			KQ_UNLOCK(kq);
+			continue;
+		}
+		knlist_remove_kq(knl, kn, 1, 1);
+		if (killkn) {
+			kn->kn_status |= KN_INFLUX | KN_DETACHED;
+			KQ_UNLOCK(kq);
+			knote_drop(kn, td);
+		} else {
+			/* Make sure cleared knotes disappear soon */
+			kn->kn_flags |= (EV_EOF | EV_ONESHOT);
+			KQ_UNLOCK(kq);
+		}
+		kq = NULL;
+	}
+
+	if (!SLIST_EMPTY(&knl->kl_list)) {
+		/* there are still KN_INFLUX remaining */
+		kn = SLIST_FIRST(&knl->kl_list);
+		kq = kn->kn_kq;
+		KQ_LOCK(kq);
+		KASSERT(kn->kn_status & KN_INFLUX,
+		    ("knote removed w/o list lock"));
+		knl->kl_unlock(knl->kl_lockarg);
+		kq->kq_state |= KQ_FLUXWAIT;
+		msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqkclr", 0);
+		kq = NULL;
+		goto again;
+	}
+
+	if (islocked)
+		KNL_ASSERT_LOCKED(knl);
+	else {
+		knl->kl_unlock(knl->kl_lockarg);
+		KNL_ASSERT_UNLOCKED(knl);
+	}
+}
+
+/*
+ * Remove all knotes referencing a specified fd must be called with FILEDESC
+ * lock.  This prevents a race where a new fd comes along and occupies the
+ * entry and we attach a knote to the fd.
+ */
+void
+knote_fdclose(struct thread *td, int fd)
+{
+	struct filedesc *fdp = td->td_proc->p_fd;
+	struct kqueue *kq;
+	struct knote *kn;
+	int influx;
+
+	FILEDESC_XLOCK_ASSERT(fdp);
+
+	/*
+	 * We shouldn't have to worry about new kevents appearing on fd
+	 * since filedesc is locked.
+	 */
+	SLIST_FOREACH(kq, &fdp->fd_kqlist, kq_list) {
+		KQ_LOCK(kq);
+
+again:
+		influx = 0;
+		while (kq->kq_knlistsize > fd &&
+		    (kn = SLIST_FIRST(&kq->kq_knlist[fd])) != NULL) {
+			if (kn->kn_status & KN_INFLUX) {
+				/* someone else might be waiting on our knote */
+				if (influx)
+					wakeup(kq);
+				kq->kq_state |= KQ_FLUXWAIT;
+				msleep(kq, &kq->kq_lock, PSOCK, "kqflxwt", 0);
+				goto again;
+			}
+			kn->kn_status |= KN_INFLUX;
+			KQ_UNLOCK(kq);
+			if (!(kn->kn_status & KN_DETACHED))
+				kn->kn_fop->f_detach(kn);
+			knote_drop(kn, td);
+			influx = 1;
+			KQ_LOCK(kq);
+		}
+		KQ_UNLOCK_FLUX(kq);
+	}
+}
+
+static int
+knote_attach(struct knote *kn, struct kqueue *kq)
+{
+	struct klist *list;
+
+	KASSERT(kn->kn_status & KN_INFLUX, ("knote not marked INFLUX"));
+	KQ_OWNED(kq);
+
+	if (kn->kn_fop->f_isfd) {
+		if (kn->kn_id >= kq->kq_knlistsize)
+			return ENOMEM;
+		list = &kq->kq_knlist[kn->kn_id];
+	} else {
+		if (kq->kq_knhash == NULL)
+			return ENOMEM;
+		list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)];
+	}
+
+	SLIST_INSERT_HEAD(list, kn, kn_link);
+
+	return 0;
+}
+
+/*
+ * knote must already have been detached using the f_detach method.
+ * no lock need to be held, it is assumed that the KN_INFLUX flag is set
+ * to prevent other removal.
+ */
+static void
+knote_drop(struct knote *kn, struct thread *td)
+{
+	struct kqueue *kq;
+	struct klist *list;
+
+	kq = kn->kn_kq;
+
+	KQ_NOTOWNED(kq);
+	KASSERT((kn->kn_status & KN_INFLUX) == KN_INFLUX,
+	    ("knote_drop called without KN_INFLUX set in kn_status"));
+
+	KQ_LOCK(kq);
+	if (kn->kn_fop->f_isfd)
+		list = &kq->kq_knlist[kn->kn_id];
+	else
+		list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)];
+
+	if (!SLIST_EMPTY(list))
+		SLIST_REMOVE(list, kn, knote, kn_link);
+	if (kn->kn_status & KN_QUEUED)
+		knote_dequeue(kn);
+	KQ_UNLOCK_FLUX(kq);
+
+	if (kn->kn_fop->f_isfd) {
+		fdrop(kn->kn_fp, td);
+		kn->kn_fp = NULL;
+	}
+	kqueue_fo_release(kn->kn_kevent.filter);
+	kn->kn_fop = NULL;
+	knote_free(kn);
+}
+
+static void
+knote_enqueue(struct knote *kn)
+{
+	struct kqueue *kq = kn->kn_kq;
+
+	KQ_OWNED(kn->kn_kq);
+	KASSERT((kn->kn_status & KN_QUEUED) == 0, ("knote already queued"));
+
+	TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe);
+	kn->kn_status |= KN_QUEUED;
+	kq->kq_count++;
+	kqueue_wakeup(kq);
+}
+
+static void
+knote_dequeue(struct knote *kn)
+{
+	struct kqueue *kq = kn->kn_kq;
+
+	KQ_OWNED(kn->kn_kq);
+	KASSERT(kn->kn_status & KN_QUEUED, ("knote not queued"));
+
+	TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe);
+	kn->kn_status &= ~KN_QUEUED;
+	kq->kq_count--;
+}
+
+static void
+knote_init(void)
+{
+
+	knote_zone = uma_zcreate("KNOTE", sizeof(struct knote), NULL, NULL,
+	    NULL, NULL, UMA_ALIGN_PTR, 0);
+}
+SYSINIT(knote, SI_SUB_PSEUDO, SI_ORDER_ANY, knote_init, NULL);
+
+static struct knote *
+knote_alloc(int waitok)
+{
+	return ((struct knote *)uma_zalloc(knote_zone,
+	    (waitok ? M_WAITOK : M_NOWAIT)|M_ZERO));
+}
+
+static void
+knote_free(struct knote *kn)
+{
+	if (kn != NULL)
+		uma_zfree(knote_zone, kn);
+}
+
+/*
+ * Register the kev w/ the kq specified by fd.
+ */
+int 
+kqfd_register(int fd, struct kevent *kev, struct thread *td, int waitok)
+{
+	struct kqueue *kq;
+	struct file *fp;
+	int error;
+
+	if ((error = fget(td, fd, &fp)) != 0)
+		return (error);
+	if ((error = kqueue_acquire(fp, &kq)) != 0)
+		goto noacquire;
+
+	error = kqueue_register(kq, kev, td, waitok);
+
+	kqueue_release(kq, 0);
+
+noacquire:
+	fdrop(fp, td);
+
+	return error;
+}
+#endif /* __rtems__ */