freebsd kqueue implementation

2001-07-06 08:01:32 +00:00 · 2001-07-06 08:01:32 +00:00 · dafe2b38ba
commit dafe2b38ba
parent c7ba90b340
1 changed files with 900 additions and 0 deletions
--- a/sys/kern/kern_event.c
+++ b/sys/kern/kern_event.c
@ -0,0 +1,900 @@
+/*-
+ * Copyright (c) 1999,2000,2001 Jonathan Lemon <jlemon@FreeBSD.org>
+ * 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.
+ *
+ * $FreeBSD: src/sys/kern/kern_event.c,v 1.27 2001/07/05 17:10:44 rwatson Exp $
+ */
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/kernel.h>
+#include <sys/lock.h>
+#include <sys/mutex.h>
+#include <sys/proc.h>
+#include <sys/malloc.h> 
+#include <sys/unistd.h>
+#include <sys/file.h>
+#include <sys/fcntl.h>
+#include <sys/selinfo.h>
+#include <sys/queue.h>
+#include <sys/event.h>
+#include <sys/eventvar.h>
+#include <sys/poll.h>
+#include <sys/protosw.h>
+#include <sys/socket.h>
+#include <sys/socketvar.h>
+#include <sys/stat.h>
+#include <sys/sysproto.h>
+#include <sys/uio.h>
+
+#include <vm/vm_zone.h>
+
+static int	kqueue_scan(struct file *fp, int maxevents,
+		    struct kevent *ulistp, const struct timespec *timeout,
+		    struct proc *p);
+static int 	kqueue_read(struct file *fp, struct uio *uio,
+		    struct ucred *cred, int flags, struct proc *p);
+static int	kqueue_write(struct file *fp, struct uio *uio,
+		    struct ucred *cred, int flags, struct proc *p);
+static int	kqueue_ioctl(struct file *fp, u_long com, caddr_t data,
+		    struct proc *p);
+static int 	kqueue_poll(struct file *fp, int events, struct ucred *cred,
+		    struct proc *p);
+static int 	kqueue_kqfilter(struct file *fp, struct knote *kn);
+static int 	kqueue_stat(struct file *fp, struct stat *st, struct proc *p);
+static int 	kqueue_close(struct file *fp, struct proc *p);
+static void 	kqueue_wakeup(struct kqueue *kq);
+
+static struct fileops kqueueops = {
+	kqueue_read,
+	kqueue_write,
+	kqueue_ioctl,
+	kqueue_poll,
+	kqueue_kqfilter,
+	kqueue_stat,
+	kqueue_close
+};
+
+static void 	knote_attach(struct knote *kn, struct filedesc *fdp);
+static void 	knote_drop(struct knote *kn, struct proc *p);
+static void 	knote_enqueue(struct knote *kn);
+static void 	knote_dequeue(struct knote *kn);
+static void 	knote_init(void);
+static struct 	knote *knote_alloc(void);
+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 struct filterops kqread_filtops =
+	{ 1, NULL, filt_kqdetach, filt_kqueue };
+static struct filterops proc_filtops =
+	{ 0, filt_procattach, filt_procdetach, filt_proc };
+static struct filterops file_filtops =
+	{ 1, filt_fileattach, NULL, NULL };
+
+static vm_zone_t	knote_zone;
+
+#define KNOTE_ACTIVATE(kn) do { 					\
+	kn->kn_status |= KN_ACTIVE;					\
+	if ((kn->kn_status & (KN_QUEUED | KN_DISABLED)) == 0)		\
+		knote_enqueue(kn);					\
+} while(0)
+
+#define	KN_HASHSIZE		64		/* XXX should be tunable */
+#define KN_HASH(val, mask)	(((val) ^ (val >> 8)) & (mask))
+
+extern struct filterops aio_filtops;
+extern struct filterops sig_filtops;
+
+/*
+ * Table for for all system-defined filters.
+ */
+static struct filterops *sysfilt_ops[] = {
+	&file_filtops,			/* EVFILT_READ */
+	&file_filtops,			/* EVFILT_WRITE */
+	&aio_filtops,			/* EVFILT_AIO */
+	&file_filtops,			/* EVFILT_VNODE */
+	&proc_filtops,			/* EVFILT_PROC */
+	&sig_filtops,			/* EVFILT_SIGNAL */
+};
+
+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 = (struct kqueue *)kn->kn_fp->f_data;
+
+	if (kn->kn_filter != EVFILT_READ)
+		return (1);
+
+	kn->kn_fop = &kqread_filtops;
+	SLIST_INSERT_HEAD(&kq->kq_sel.si_note, kn, kn_selnext);
+	return (0);
+}
+
+static void
+filt_kqdetach(struct knote *kn)
+{
+	struct kqueue *kq = (struct kqueue *)kn->kn_fp->f_data;
+
+	SLIST_REMOVE(&kq->kq_sel.si_note, kn, knote, kn_selnext);
+}
+
+/*ARGSUSED*/
+static int
+filt_kqueue(struct knote *kn, long hint)
+{
+	struct kqueue *kq = (struct kqueue *)kn->kn_fp->f_data;
+
+	kn->kn_data = kq->kq_count;
+	return (kn->kn_data > 0);
+}
+
+static int
+filt_procattach(struct knote *kn)
+{
+	struct proc *p;
+	int error;
+
+	p = pfind(kn->kn_id);
+	if (p == NULL)
+		return (ESRCH);
+	if ((error = p_cansee(curproc, 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;
+	}
+
+	SLIST_INSERT_HEAD(&p->p_klist, kn, kn_selnext);
+	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.
+ */
+static void
+filt_procdetach(struct knote *kn)
+{
+	struct proc *p = kn->kn_ptr.p_proc;
+
+	if (kn->kn_status & KN_DETACHED)
+		return;
+
+	PROC_LOCK(p);
+	SLIST_REMOVE(&p->p_klist, kn, knote, kn_selnext);
+	PROC_UNLOCK(p);
+}
+
+static int
+filt_proc(struct knote *kn, long hint)
+{
+	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) {
+		kn->kn_status |= KN_DETACHED;
+		kn->kn_flags |= (EV_EOF | EV_ONESHOT); 
+		return (1);
+	}
+
+	/*
+	 * process forked, and user wants to track the new process,
+	 * so attach a new knote to it, and immediately report an
+	 * event with the parent's pid.
+	 */
+	if ((event == NOTE_FORK) && (kn->kn_sfflags & NOTE_TRACK)) {
+		struct kevent kev;
+		int error;
+
+		/*
+		 * register knote with new process.
+		 */
+		kev.ident = hint & NOTE_PDATAMASK;	/* 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(kn->kn_kq, &kev, NULL);
+		if (error)
+			kn->kn_fflags |= NOTE_TRACKERR;
+	}
+
+	return (kn->kn_fflags != 0);
+}
+
+int
+kqueue(struct proc *p, struct kqueue_args *uap)
+{
+	struct filedesc *fdp = p->p_fd;
+	struct kqueue *kq;
+	struct file *fp;
+	int fd, error;
+
+	error = falloc(p, &fp, &fd);
+	if (error)
+		return (error);
+	fp->f_flag = FREAD | FWRITE;
+	fp->f_type = DTYPE_KQUEUE;
+	fp->f_ops = &kqueueops;
+	kq = malloc(sizeof(struct kqueue), M_TEMP, M_WAITOK | M_ZERO);
+	TAILQ_INIT(&kq->kq_head);
+	fp->f_data = (caddr_t)kq;
+	p->p_retval[0] = fd;
+	if (fdp->fd_knlistsize < 0)
+		fdp->fd_knlistsize = 0;		/* this process has a kq */
+	kq->kq_fdp = fdp;
+	return (error);
+}
+
+#ifndef _SYS_SYSPROTO_H_
+struct kevent_args {
+	int	fd;
+	const struct kevent *changelist;
+	int	nchanges;
+	struct	kevent *eventlist;
+	int	nevents;
+	const struct timespec *timeout;
+};
+#endif
+int
+kevent(struct proc *p, struct kevent_args *uap)
+{
+	struct filedesc* fdp = p->p_fd;
+	struct kevent *kevp;
+	struct kqueue *kq;
+	struct file *fp = NULL;
+	struct timespec ts;
+	int i, n, nerrors, error;
+
+        if (((u_int)uap->fd) >= fdp->fd_nfiles ||
+            (fp = fdp->fd_ofiles[uap->fd]) == NULL ||
+	    (fp->f_type != DTYPE_KQUEUE))
+		return (EBADF);
+
+	fhold(fp);
+
+	if (uap->timeout != NULL) {
+		error = copyin(uap->timeout, &ts, sizeof(ts));
+		if (error)
+			goto done;
+		uap->timeout = &ts;
+	}
+
+	kq = (struct kqueue *)fp->f_data;
+	nerrors = 0;
+
+	while (uap->nchanges > 0) {
+		n = uap->nchanges > KQ_NEVENTS ? KQ_NEVENTS : uap->nchanges;
+		error = copyin(uap->changelist, kq->kq_kev,
+		    n * sizeof(struct kevent));
+		if (error)
+			goto done;
+		for (i = 0; i < n; i++) {
+			kevp = &kq->kq_kev[i];
+			kevp->flags &= ~EV_SYSFLAGS;
+			error = kqueue_register(kq, kevp, p);
+			if (error) {
+				if (uap->nevents != 0) {
+					kevp->flags = EV_ERROR;
+					kevp->data = error;
+					(void) copyout((caddr_t)kevp,
+					    (caddr_t)uap->eventlist,
+					    sizeof(*kevp));
+					uap->eventlist++;
+					uap->nevents--;
+					nerrors++;
+				} else {
+					goto done;
+				}
+			}
+		}
+		uap->nchanges -= n;
+		uap->changelist += n;
+	}
+	if (nerrors) {
+        	p->p_retval[0] = nerrors;
+		error = 0;
+		goto done;
+	}
+
+	error = kqueue_scan(fp, uap->nevents, uap->eventlist, uap->timeout, p);
+done:
+	if (fp != NULL)
+		fdrop(fp, p);
+	return (error);
+}
+
+int
+kqueue_register(struct kqueue *kq, struct kevent *kev, struct proc *p)
+{
+	struct filedesc *fdp = kq->kq_fdp;
+	struct filterops *fops;
+	struct file *fp = NULL;
+	struct knote *kn = NULL;
+	int s, error = 0;
+
+	if (kev->filter < 0) {
+		if (kev->filter + EVFILT_SYSCOUNT < 0)
+			return (EINVAL);
+		fops = sysfilt_ops[~kev->filter];	/* to 0-base index */
+	} else {
+		/*
+		 * XXX
+		 * filter attach routine is responsible for insuring that
+		 * the identifier can be attached to it.
+		 */
+		printf("unknown filter: %d\n", kev->filter);
+		return (EINVAL);
+	}
+
+	if (fops->f_isfd) {
+		/* validate descriptor */
+		if ((u_int)kev->ident >= fdp->fd_nfiles ||
+		    (fp = fdp->fd_ofiles[kev->ident]) == NULL)
+			return (EBADF);
+		fhold(fp);
+
+		if (kev->ident < fdp->fd_knlistsize) {
+			SLIST_FOREACH(kn, &fdp->fd_knlist[kev->ident], kn_link)
+				if (kq == kn->kn_kq &&
+				    kev->filter == kn->kn_filter)
+					break;
+		}
+	} else {
+		if (fdp->fd_knhashmask != 0) {
+			struct klist *list;
+			
+			list = &fdp->fd_knhash[
+			    KN_HASH((u_long)kev->ident, fdp->fd_knhashmask)];
+			SLIST_FOREACH(kn, list, kn_link)
+				if (kev->ident == kn->kn_id &&
+				    kq == kn->kn_kq &&
+				    kev->filter == kn->kn_filter)
+					break;
+		}
+	}
+
+	if (kn == NULL && ((kev->flags & EV_ADD) == 0)) {
+		error = ENOENT;
+		goto done;
+	}
+
+	/*
+	 * kn now contains the matching knote, or NULL if no match
+	 */
+	if (kev->flags & EV_ADD) {
+
+		if (kn == NULL) {
+			kn = knote_alloc();
+			if (kn == NULL) {
+				error = ENOMEM;
+				goto done;
+			}
+			kn->kn_fp = fp;
+			kn->kn_kq = kq;
+			kn->kn_fop = fops;
+
+			/*
+			 * apply reference count to knote structure, and
+			 * do not release it at the end of this routine.
+			 */
+			fp = NULL;
+
+			kn->kn_sfflags = kev->fflags;
+			kn->kn_sdata = kev->data;
+			kev->fflags = 0;
+			kev->data = 0;
+			kn->kn_kevent = *kev;
+
+			knote_attach(kn, fdp);
+			if ((error = fops->f_attach(kn)) != 0) {
+				knote_drop(kn, p);
+				goto done;
+			}
+		} else {
+			/*
+			 * The user may change some filter values after the
+			 * initial EV_ADD, but doing so will not reset any 
+			 * filter which have already been triggered.
+			 */
+			kn->kn_sfflags = kev->fflags;
+			kn->kn_sdata = kev->data;
+			kn->kn_kevent.udata = kev->udata;
+		}
+
+		s = splhigh();
+		if (kn->kn_fop->f_event(kn, 0))
+			KNOTE_ACTIVATE(kn);
+		splx(s);
+
+	} else if (kev->flags & EV_DELETE) {
+		kn->kn_fop->f_detach(kn);
+		knote_drop(kn, p);
+		goto done;
+	}
+
+	if ((kev->flags & EV_DISABLE) &&
+	    ((kn->kn_status & KN_DISABLED) == 0)) {
+		s = splhigh();
+		kn->kn_status |= KN_DISABLED;
+		splx(s);
+	}
+
+	if ((kev->flags & EV_ENABLE) && (kn->kn_status & KN_DISABLED)) {
+		s = splhigh();
+		kn->kn_status &= ~KN_DISABLED;
+		if ((kn->kn_status & KN_ACTIVE) &&
+		    ((kn->kn_status & KN_QUEUED) == 0))
+			knote_enqueue(kn);
+		splx(s);
+	}
+
+done:
+	if (fp != NULL)
+		fdrop(fp, p);
+	return (error);
+}
+
+static int
+kqueue_scan(struct file *fp, int maxevents, struct kevent *ulistp,
+	const struct timespec *tsp, struct proc *p)
+{
+	struct kqueue *kq = (struct kqueue *)fp->f_data;
+	struct kevent *kevp;
+	struct timeval atv, rtv, ttv;
+	struct knote *kn, marker;
+	int s, count, timeout, nkev = 0, error = 0;
+
+	count = maxevents;
+	if (count == 0)
+		goto done;
+
+	if (tsp != NULL) {
+		TIMESPEC_TO_TIMEVAL(&atv, tsp);
+		if (itimerfix(&atv)) {
+			error = EINVAL;
+			goto done;
+		}
+		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;
+	}
+	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 = kq->kq_kev;
+	s = splhigh();
+	if (kq->kq_count == 0) {
+		if (timeout < 0) { 
+			error = EWOULDBLOCK;
+		} else {
+			kq->kq_state |= KQ_SLEEP;
+			error = tsleep(kq, PSOCK | PCATCH, "kqread", timeout);
+		}
+		splx(s);
+		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); 
+	while (count) {
+		kn = TAILQ_FIRST(&kq->kq_head);
+		TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe); 
+		if (kn == &marker) {
+			splx(s);
+			if (count == maxevents)
+				goto retry;
+			goto done;
+		}
+		if (kn->kn_status & KN_DISABLED) {
+			kn->kn_status &= ~KN_QUEUED;
+			kq->kq_count--;
+			continue;
+		}
+		if ((kn->kn_flags & EV_ONESHOT) == 0 &&
+		    kn->kn_fop->f_event(kn, 0) == 0) {
+			kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE);
+			kq->kq_count--;
+			continue;
+		}
+		*kevp = kn->kn_kevent;
+		kevp++;
+		nkev++;
+		if (kn->kn_flags & EV_ONESHOT) {
+			kn->kn_status &= ~KN_QUEUED;
+			kq->kq_count--;
+			splx(s);
+			kn->kn_fop->f_detach(kn);
+			knote_drop(kn, p);
+			s = splhigh();
+		} else if (kn->kn_flags & EV_CLEAR) {
+			kn->kn_data = 0;
+			kn->kn_fflags = 0;
+			kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE);
+			kq->kq_count--;
+		} else {
+			TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe); 
+		}
+		count--;
+		if (nkev == KQ_NEVENTS) {
+			splx(s);
+			error = copyout((caddr_t)&kq->kq_kev, (caddr_t)ulistp,
+			    sizeof(struct kevent) * nkev);
+			ulistp += nkev;
+			nkev = 0;
+			kevp = kq->kq_kev;
+			s = splhigh();
+			if (error)
+				break;
+		}
+	}
+	TAILQ_REMOVE(&kq->kq_head, &marker, kn_tqe); 
+	splx(s);
+done:
+	if (nkev != 0)
+		error = copyout((caddr_t)&kq->kq_kev, (caddr_t)ulistp,
+		    sizeof(struct kevent) * nkev);
+        p->p_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 *cred,
+	int flags, struct proc *p)
+{
+	return (ENXIO);
+}
+
+/*ARGSUSED*/
+static int
+kqueue_write(struct file *fp, struct uio *uio, struct ucred *cred,
+	 int flags, struct proc *p)
+{
+	return (ENXIO);
+}
+
+/*ARGSUSED*/
+static int
+kqueue_ioctl(struct file *fp, u_long com, caddr_t data, struct proc *p)
+{
+	return (ENOTTY);
+}
+
+/*ARGSUSED*/
+static int
+kqueue_poll(struct file *fp, int events, struct ucred *cred, struct proc *p)
+{
+	struct kqueue *kq = (struct kqueue *)fp->f_data;
+	int revents = 0;
+	int s = splnet();
+
+        if (events & (POLLIN | POLLRDNORM)) {
+                if (kq->kq_count) {
+                        revents |= events & (POLLIN | POLLRDNORM);
+		} else {
+                        selrecord(p, &kq->kq_sel);
+			kq->kq_state |= KQ_SEL;
+		}
+	}
+	splx(s);
+	return (revents);
+}
+
+/*ARGSUSED*/
+static int
+kqueue_stat(struct file *fp, struct stat *st, struct proc *p)
+{
+	struct kqueue *kq = (struct kqueue *)fp->f_data;
+
+	bzero((void *)st, sizeof(*st));
+	st->st_size = kq->kq_count;
+	st->st_blksize = sizeof(struct kevent);
+	st->st_mode = S_IFIFO;
+	return (0);
+}
+
+/*ARGSUSED*/
+static int
+kqueue_close(struct file *fp, struct proc *p)
+{
+	struct kqueue *kq = (struct kqueue *)fp->f_data;
+	struct filedesc *fdp = p->p_fd;
+	struct knote **knp, *kn, *kn0;
+	int i;
+
+	for (i = 0; i < fdp->fd_knlistsize; i++) {
+		knp = &SLIST_FIRST(&fdp->fd_knlist[i]);
+		kn = *knp;
+		while (kn != NULL) {
+			kn0 = SLIST_NEXT(kn, kn_link);
+			if (kq == kn->kn_kq) {
+				kn->kn_fop->f_detach(kn);
+				fdrop(kn->kn_fp, p);
+				knote_free(kn);
+				*knp = kn0;
+			} else {
+				knp = &SLIST_NEXT(kn, kn_link);
+			}
+			kn = kn0;
+		}
+	}
+	if (fdp->fd_knhashmask != 0) {
+		for (i = 0; i < fdp->fd_knhashmask + 1; i++) {
+			knp = &SLIST_FIRST(&fdp->fd_knhash[i]);
+			kn = *knp;
+			while (kn != NULL) {
+				kn0 = SLIST_NEXT(kn, kn_link);
+				if (kq == kn->kn_kq) {
+					kn->kn_fop->f_detach(kn);
+		/* XXX non-fd release of kn->kn_ptr */
+					knote_free(kn);
+					*knp = kn0;
+				} else {
+					knp = &SLIST_NEXT(kn, kn_link);
+				}
+				kn = kn0;
+			}
+		}
+	}
+	free(kq, M_TEMP);
+	fp->f_data = NULL;
+
+	return (0);
+}
+
+static void
+kqueue_wakeup(struct kqueue *kq)
+{
+
+	if (kq->kq_state & KQ_SLEEP) {
+		kq->kq_state &= ~KQ_SLEEP;
+		wakeup(kq);
+	}
+	if (kq->kq_state & KQ_SEL) {
+		kq->kq_state &= ~KQ_SEL;
+		selwakeup(&kq->kq_sel);
+	}
+	KNOTE(&kq->kq_sel.si_note, 0);
+}
+
+/*
+ * walk down a list of knotes, activating them if their event has triggered.
+ */
+void
+knote(struct klist *list, long hint)
+{
+	struct knote *kn;
+
+	SLIST_FOREACH(kn, list, kn_selnext)
+		if (kn->kn_fop->f_event(kn, hint))
+			KNOTE_ACTIVATE(kn);
+}
+
+/*
+ * remove all knotes from a specified klist
+ */
+void
+knote_remove(struct proc *p, struct klist *list)
+{
+	struct knote *kn;
+
+	while ((kn = SLIST_FIRST(list)) != NULL) {
+		kn->kn_fop->f_detach(kn);
+		knote_drop(kn, p);
+	}
+}
+
+/*
+ * remove all knotes referencing a specified fd
+ */
+void
+knote_fdclose(struct proc *p, int fd)
+{
+	struct filedesc *fdp = p->p_fd;
+	struct klist *list = &fdp->fd_knlist[fd];
+
+	knote_remove(p, list);
+}
+
+static void
+knote_attach(struct knote *kn, struct filedesc *fdp)
+{
+	struct klist *list;
+	int size;
+
+	if (! kn->kn_fop->f_isfd) {
+		if (fdp->fd_knhashmask == 0)
+			fdp->fd_knhash = hashinit(KN_HASHSIZE, M_TEMP,
+			    &fdp->fd_knhashmask);
+		list = &fdp->fd_knhash[KN_HASH(kn->kn_id, fdp->fd_knhashmask)];
+		goto done;
+	}
+
+	if (fdp->fd_knlistsize <= kn->kn_id) {
+		size = fdp->fd_knlistsize;
+		while (size <= kn->kn_id)
+			size += KQEXTENT;
+		MALLOC(list, struct klist *,
+		    size * sizeof(struct klist *), M_TEMP, M_WAITOK);
+		bcopy((caddr_t)fdp->fd_knlist, (caddr_t)list,
+		    fdp->fd_knlistsize * sizeof(struct klist *));
+		bzero((caddr_t)list +
+		    fdp->fd_knlistsize * sizeof(struct klist *),
+		    (size - fdp->fd_knlistsize) * sizeof(struct klist *));
+		if (fdp->fd_knlist != NULL)
+			FREE(fdp->fd_knlist, M_TEMP);
+		fdp->fd_knlistsize = size;
+		fdp->fd_knlist = list;
+	}
+	list = &fdp->fd_knlist[kn->kn_id];
+done:
+	SLIST_INSERT_HEAD(list, kn, kn_link);
+	kn->kn_status = 0;
+}
+
+/*
+ * should be called at spl == 0, since we don't want to hold spl
+ * while calling fdrop and free.
+ */
+static void
+knote_drop(struct knote *kn, struct proc *p)
+{
+        struct filedesc *fdp = p->p_fd;
+	struct klist *list;
+
+	if (kn->kn_fop->f_isfd)
+		list = &fdp->fd_knlist[kn->kn_id];
+	else
+		list = &fdp->fd_knhash[KN_HASH(kn->kn_id, fdp->fd_knhashmask)];
+
+	SLIST_REMOVE(list, kn, knote, kn_link);
+	if (kn->kn_status & KN_QUEUED)
+		knote_dequeue(kn);
+	if (kn->kn_fop->f_isfd)
+		fdrop(kn->kn_fp, p);
+	knote_free(kn);
+}
+
+
+static void
+knote_enqueue(struct knote *kn)
+{
+	struct kqueue *kq = kn->kn_kq;
+	int s = splhigh();
+
+	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++;
+	splx(s);
+	kqueue_wakeup(kq);
+}
+
+static void
+knote_dequeue(struct knote *kn)
+{
+	struct kqueue *kq = kn->kn_kq;
+	int s = splhigh();
+
+	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--;
+	splx(s);
+}
+
+static void
+knote_init(void)
+{
+	knote_zone = zinit("KNOTE", sizeof(struct knote), 0, 0, 1);
+}
+SYSINIT(knote, SI_SUB_PSEUDO, SI_ORDER_ANY, knote_init, NULL)
+
+static struct knote *
+knote_alloc(void)
+{
+	return ((struct knote *)zalloc(knote_zone));
+}
+
+static void
+knote_free(struct knote *kn)
+{
+	zfree(knote_zone, kn);
+}