xnu-517.tar.gz

[apple/xnu.git] / bsd / kern / kern_event.c

/*
 * Copyright (c) 2000-2003 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
 * 
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this
 * file.
 * 
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 * 
 * @APPLE_LICENSE_HEADER_END@
 *
 */
/*-
 * 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.
 */
/*
 *      @(#)kern_event.c       1.0 (3/31/2000)
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/filedesc.h>
#include <sys/kernel.h>
#include <sys/proc.h>
#include <sys/malloc.h> 
#include <sys/unistd.h>
#include <sys/file.h>
#include <sys/fcntl.h>
#include <sys/select.h>
#include <sys/queue.h>
#include <sys/event.h>
#include <sys/eventvar.h>
#include <sys/protosw.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/stat.h>
#include <sys/sysctl.h>
#include <sys/uio.h>

#include <kern/zalloc.h>

MALLOC_DEFINE(M_KQUEUE, "kqueue", "memory for kqueue system");

static int      kqueue_scan(struct file *fp, int maxevents,
                    struct kevent *ulistp, const struct timespec *timeout,
                    register_t *retval, struct proc *p);
static void     kqueue_wakeup(struct kqueue *kq);

static int      kqueue_read __P((struct file *fp, struct uio *uio,
                    struct ucred *cred, int flags, struct proc *p));
static int      kqueue_write __P((struct file *fp, struct uio *uio,
                    struct ucred *cred, int flags, struct proc *p));
static int      kqueue_ioctl __P((struct file *fp, u_long com, caddr_t data,
                    struct proc *p));
static int      kqueue_select __P((struct file *fp, int which, void *wql, 
                    struct proc *p));
static int      kqueue_close __P((struct file *fp, struct proc *p));
static int      kqueue_kqfilter __P((struct file *fp, struct knote *kn, struct proc *p));

static struct fileops kqueueops = {
        kqueue_read,
        kqueue_write,
        kqueue_ioctl,
        kqueue_select,
        kqueue_close,
        kqueue_kqfilter
};

static void     knote_fdpattach(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 struct   knote *knote_alloc(void);
static void     knote_free(struct knote *kn);

static int      filt_fileattach(struct knote *kn);
static struct filterops file_filtops =
        { 1, filt_fileattach, NULL, NULL };

static void     filt_kqdetach(struct knote *kn);
static int      filt_kqueue(struct knote *kn, long hint);
static struct filterops kqread_filtops =
        { 1, NULL, filt_kqdetach, filt_kqueue };

/*
 * JMM - placeholder for not-yet-implemented filters
 */ 
static int      filt_badattach(struct knote *kn);
static struct filterops bad_filtops =
        { 0, filt_badattach, 0 , 0 };

static int      filt_procattach(struct knote *kn);
static void     filt_procdetach(struct knote *kn);
static int      filt_proc(struct knote *kn, long hint);

static struct filterops proc_filtops =
        { 0, filt_procattach, filt_procdetach, filt_proc };

extern struct filterops fs_filtops;

extern struct filterops sig_filtops;

#if 0
/* JMM - We don't implement these now */
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 struct filterops timer_filtops =
        { 0, filt_timerattach, filt_timerdetach, filt_timer };

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");
#endif /* 0 */

static 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))

#if 0
extern struct filterops aio_filtops;
#endif

/*
 * Table for for all system-defined filters.
 */
static struct filterops *sysfilt_ops[] = {
        &file_filtops,                  /* EVFILT_READ */
        &file_filtops,                  /* EVFILT_WRITE */
#if 0
        &aio_filtops,                   /* EVFILT_AIO */
#else
        &bad_filtops,                   /* EVFILT_AIO */
#endif
        &file_filtops,                  /* EVFILT_VNODE */
        &proc_filtops,                  /* EVFILT_PROC */
        &sig_filtops,                   /* EVFILT_SIGNAL */
#if 0
        &timer_filtops,                 /* EVFILT_TIMER */
#else
        &bad_filtops,                   /* EVFILT_TIMER */
#endif
        &bad_filtops,                   /* EVFILT_MACHPORT */
        &fs_filtops             /* EVFILT_FS */
};

static int
filt_fileattach(struct knote *kn)
{
        
        return (fo_kqfilter(kn->kn_fp, kn, current_proc()));
}

static void
filt_kqdetach(struct knote *kn)
{
        struct kqueue *kq = (struct kqueue *)kn->kn_fp->f_data;

        if (kq->kq_state & KQ_SEL)
          return;

        KNOTE_DETACH(&kq->kq_sel.si_note, kn);
}

/*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;

        p = pfind(kn->kn_id);
        if (p == NULL)
                return (ESRCH);
        if (! PRISON_CHECK(current_proc(), p))
                return (EACCES);

        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;
        }

        /* XXX lock the proc here while adding to the list? */
        KNOTE_ATTACH(&p->p_klist, kn);

        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;

        /* XXX locking?  this might modify another process. */
        KNOTE_DETACH(&p->p_klist, kn);
}

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);
}

#if 0
static void
filt_timerexpire(void *knx)
{
        struct knote *kn = knx;
        struct callout *calloutp;
        struct timeval tv;
        int tticks;

        kn->kn_data++;
        KNOTE_ACTIVATE(kn);

        if ((kn->kn_flags & EV_ONESHOT) == 0) {
                tv.tv_sec = kn->kn_sdata / 1000;
                tv.tv_usec = (kn->kn_sdata % 1000) * 1000;
                tticks = tvtohz(&tv);
                calloutp = (struct callout *)kn->kn_hook;
                callout_reset(calloutp, tticks, filt_timerexpire, kn);
        }
}

/*
 * data contains amount of time to sleep, in milliseconds
 */ 
static int
filt_timerattach(struct knote *kn)
{
        struct callout *calloutp;
        struct timeval tv;
        int tticks;

        if (kq_ncallouts >= kq_calloutmax)
                return (ENOMEM);
        kq_ncallouts++;

        tv.tv_sec = kn->kn_sdata / 1000;
        tv.tv_usec = (kn->kn_sdata % 1000) * 1000;
        tticks = tvtohz(&tv);

        kn->kn_flags |= EV_CLEAR;               /* automatically set */
        MALLOC(calloutp, struct callout *, sizeof(*calloutp),
            M_KQUEUE, M_WAITOK);
        callout_init(calloutp);
        callout_reset(calloutp, tticks, filt_timerexpire, kn);
        kn->kn_hook = (caddr_t)calloutp;

        return (0);
}

static void
filt_timerdetach(struct knote *kn)
{
        struct callout *calloutp;

        calloutp = (struct callout *)kn->kn_hook;
        callout_stop(calloutp);
        FREE(calloutp, M_KQUEUE);
        kq_ncallouts--;
}

static int
filt_timer(struct knote *kn, long hint)
{

        return (kn->kn_data != 0);
}
#endif /* 0 */

/*
 * JMM - placeholder for not-yet-implemented filters
 */ 
static int
filt_badattach(struct knote *kn)
{
        return(EOPNOTSUPP);
}

#ifndef _SYS_SYSPROTO_H_
struct kqueue_args {
        int dummy;
};
#endif

int
kqueue(struct proc *p, struct kqueue_args *uap, register_t *retval)
{
        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 = (struct kqueue *)_MALLOC(sizeof(struct kqueue), M_KQUEUE, M_WAITOK | M_ZERO);
        TAILQ_INIT(&kq->kq_head);
        fp->f_data = (caddr_t)kq;
        *retval = 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 kqueue_portset_np_args {
        int     fd;
};
#endif
int
kqueue_portset_np(struct proc *p, struct kqueue_portset_np_args *uap, register_t *retval)
{
                /* JMM - Placeholder for now */
                return (EOPNOTSUPP);
}

#ifndef _SYS_SYSPROTO_H_
struct kqueue_from_portset_np_args {
        int     fd;
};
#endif
int
kqueue_from_portset_np(struct proc *p, struct kqueue_from_portset_np_args *uap, register_t *retval)
{
                /* JMM - Placeholder for now */
                return (EOPNOTSUPP);
}

#if !0
/* JMM - We don't implement this yet */
#define fhold(fp)
#define fdrop(fp, p)
#endif /* !0 */

#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, register_t *retval)
{
        struct filedesc* fdp = p->p_fd;
        struct kqueue *kq;
        struct file *fp = NULL;
        struct timespec ts;
        int i, nerrors, error;

        if (uap->timeout != NULL) {
                error = copyin((caddr_t)uap->timeout, (caddr_t)&ts, sizeof(ts));
                if (error)
                        goto done;
                uap->timeout = &ts;
        }

        if (((u_int)uap->fd) >= fdp->fd_nfiles ||
            (fp = fdp->fd_ofiles[uap->fd]) == NULL ||
            (fp->f_type != DTYPE_KQUEUE))
                return (EBADF);

        fhold(fp);

        kq = (struct kqueue *)fp->f_data;
        nerrors = 0;

        while (uap->nchanges > 0) {
                int i;
                int n = uap->nchanges > KQ_NEVENTS ? KQ_NEVENTS : uap->nchanges;
                struct kevent kq_kev[n];

                error = copyin((caddr_t)uap->changelist, (caddr_t)kq_kev,
                    n * sizeof(struct kevent));
                if (error)
                        goto done;
                for (i = 0; i < n; i++) {
                        struct kevent *kevp = &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) {
                *retval = nerrors;
                error = 0;
                goto done;
        }

        error = kqueue_scan(fp, uap->nevents, uap->eventlist, uap->timeout, retval, 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_fdpattach(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, register_t *retval, struct proc *p)
{
        struct kqueue *kq = (struct kqueue *)fp->f_data;
        struct timeval atv, rtv, ttv;
        int s, count, timeout, error = 0;
        struct knote marker;

        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:
        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;
        }

        /* JMM - This marker trick doesn't work with multiple threads */
        TAILQ_INSERT_TAIL(&kq->kq_head, &marker, kn_tqe); 
        while (count) {
                int maxkev = (count > KQ_NEVENTS) ? KQ_NEVENTS : count;
                struct kevent kq_kev[maxkev];
                struct kevent *kevp = kq_kev;
                struct knote *kn;
                int nkev = 0;

                while (nkev < maxkev) {
                        kn = TAILQ_FIRST(&kq->kq_head);
                        TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe); 
                        if (kn == &marker) {
                                if (count == maxevents)
                                        goto retry;
                                break;
                        } else if (kn->kn_status & KN_DISABLED) {
                                kn->kn_status &= ~KN_QUEUED;
                                kq->kq_count--;
                                continue;
                        } else 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++;
                        count--;

                        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); 
                        }
                }
                splx(s);
                error = copyout((caddr_t)kq_kev, (caddr_t)ulistp,
                                sizeof(struct kevent) * nkev);
                if (kn == &marker)
                        goto done;
                ulistp += nkev;
                s = splhigh();
                if (error)
                        break;
        }
        TAILQ_REMOVE(&kq->kq_head, &marker, kn_tqe); 
        splx(s);
done:
        *retval = 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_select(struct file *fp, int which, void *wql, struct proc *p)
{
        struct kqueue *kq = (struct kqueue *)fp->f_data;
        int retnum = 0;
        int s = splnet();

        if (which == FREAD) {
                if (kq->kq_count) {
                        retnum = 1;
                } else {
                        selrecord(p, &kq->kq_sel, wql);
                        kq->kq_state |= KQ_SEL;
                }
        }
        splx(s);
        return (retnum);
}

/*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_KQUEUE);
        fp->f_data = NULL;

        return (0);
}

/*ARGSUSED*/
static int
kqueue_kqfilter(struct file *fp, struct knote *kn, struct proc *p)
{
        struct kqueue *kq = (struct kqueue *)kn->kn_fp->f_data;

        if (kn->kn_filter != EVFILT_READ || (kq->kq_state & KQ_SEL))
                return (1);

        kn->kn_fop = &kqread_filtops;
        KNOTE_ATTACH(&kq->kq_sel.si_note, kn);
        return (0);
}

/*ARGSUSED*/
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);
}

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; /* remove for now */
                selwakeup(&kq->kq_sel);
        } else
                KNOTE(&kq->kq_sel.si_note, 0);
}

void
klist_init(struct klist *list)
{
        SLIST_INIT(list);
}

/*
 * 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);
}

/*
 * attach a knote to the specified list.  Return true if this is the first entry.
 */
int
knote_attach(struct klist *list, struct knote *kn)
{
        int ret = SLIST_EMPTY(list);
        SLIST_INSERT_HEAD(list, kn, kn_selnext);
        return ret;
}

/*
 * detach a knote from the specified list.  Return true if that was the last entry.
 */
int
knote_detach(struct klist *list, struct knote *kn)
{
        SLIST_REMOVE(list, kn, knote, kn_selnext);
        return SLIST_EMPTY(list);
}

/*
 * 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_fdpattach(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_KQUEUE,
                            &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_KQUEUE, 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_KQUEUE);
                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);
}

void
knote_init(void)
{
        knote_zone = zinit(sizeof(struct knote), 8192*sizeof(struct knote), 8192, "knote zone");
}
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, (vm_offset_t)kn);
}

#include <sys/param.h>
#include <sys/socket.h>
#include <sys/protosw.h>
#include <sys/domain.h>
#include <sys/mbuf.h>
#include <sys/kern_event.h>
#include <sys/malloc.h>
#include <sys/sys_domain.h>
#include <sys/syslog.h>


int     raw_usrreq();
struct pr_usrreqs event_usrreqs;

struct protosw eventsw[] = {
     {
          SOCK_RAW,             &systemdomain,  SYSPROTO_EVENT,         PR_ATOMIC,
          0,            0,              0,              0,
          0,
          0,            0,              0,              0,
          0,            &event_usrreqs
     }
};

static
struct kern_event_head kern_event_head;

static u_long static_event_id = 0;

/*
 * Install the protosw's for the NKE manager.  Invoked at
 *  extension load time
 */
int
kern_event_init(void)
{
    int retval;

    if ((retval = net_add_proto(eventsw, &systemdomain)) == 0)
            return(KERN_SUCCESS);
    
    log(LOG_WARNING, "Can't install kernel events protocol (%d)\n", retval);
    return(retval);
}

int kev_attach(struct socket *so, int proto, struct proc *p)
{
     int error;
     struct kern_event_pcb  *ev_pcb;

     error = soreserve(so, KEV_SNDSPACE, KEV_RECVSPACE);
     if (error)
          return error;

     ev_pcb = _MALLOC(sizeof(struct kern_event_pcb), M_PCB, M_WAITOK);
     if (ev_pcb == 0)
          return ENOBUFS;

     ev_pcb->ev_socket = so;
     ev_pcb->vendor_code_filter = 0xffffffff;

     so->so_pcb = (caddr_t) ev_pcb;
     LIST_INSERT_HEAD(&kern_event_head, ev_pcb, ev_link);

     return 0;
}


int kev_detach(struct socket *so)
{
     struct kern_event_pcb *ev_pcb = (struct kern_event_pcb *) so->so_pcb;

     if (ev_pcb != 0) {
          LIST_REMOVE(ev_pcb, ev_link);
          FREE(ev_pcb, M_PCB);
          so->so_pcb = 0;
     }

     return 0;
}


int  kev_post_msg(struct kev_msg *event_msg)
{
     struct mbuf *m, *m2;
     struct kern_event_pcb  *ev_pcb;
     struct kern_event_msg  *ev;
     char              *tmp;
     int               total_size;
     int               i;


     m = m_get(M_DONTWAIT, MT_DATA);
     if (m == 0)
          return ENOBUFS;

     ev = mtod(m, struct kern_event_msg *);
     total_size = KEV_MSG_HEADER_SIZE;

     tmp = (char *) &ev->event_data[0];
     for (i = 0; i < 5; i++) {
          if (event_msg->dv[i].data_length == 0)
               break;

          total_size += event_msg->dv[i].data_length;
          bcopy(event_msg->dv[i].data_ptr, tmp, 
                event_msg->dv[i].data_length);
          tmp += event_msg->dv[i].data_length;
     }


     ev->id = ++static_event_id;
     ev->total_size   = total_size;
     ev->vendor_code  = event_msg->vendor_code;
     ev->kev_class    = event_msg->kev_class;
     ev->kev_subclass = event_msg->kev_subclass;
     ev->event_code   = event_msg->event_code;

     m->m_len = total_size;
     for (ev_pcb = LIST_FIRST(&kern_event_head); 
          ev_pcb; 
          ev_pcb = LIST_NEXT(ev_pcb, ev_link)) {

          if (ev_pcb->vendor_code_filter != KEV_ANY_VENDOR) {
               if (ev_pcb->vendor_code_filter != ev->vendor_code)
                    continue;

               if (ev_pcb->class_filter != KEV_ANY_CLASS) {
                    if (ev_pcb->class_filter != ev->kev_class)
                         continue;

                    if ((ev_pcb->subclass_filter != KEV_ANY_SUBCLASS) &&
                        (ev_pcb->subclass_filter != ev->kev_subclass))
                         continue;
               }
          }

          m2 = m_copym(m, 0, m->m_len, M_NOWAIT);
          if (m2 == 0) {
               m_free(m);
               return ENOBUFS;
          }

          sbappendrecord(&ev_pcb->ev_socket->so_rcv, m2);
          sorwakeup(ev_pcb->ev_socket);
     }


     m_free(m);
     return 0;
}


int kev_control(so, cmd, data, ifp, p)
    struct socket *so;
    u_long cmd;
    caddr_t data;
    register struct ifnet *ifp;
    struct proc *p;
{
     struct kev_request *kev_req = (struct kev_request *) data;
     int  stat = 0;
     struct kern_event_pcb  *ev_pcb;
     u_long  *id_value = (u_long *) data;


     switch (cmd) {

     case SIOCGKEVID:
          *id_value = static_event_id;
          break;

     case SIOCSKEVFILT:
          ev_pcb = (struct kern_event_pcb *) so->so_pcb;
          ev_pcb->vendor_code_filter = kev_req->vendor_code;
          ev_pcb->class_filter     = kev_req->kev_class;
          ev_pcb->subclass_filter  = kev_req->kev_subclass;
          break;

     case SIOCGKEVFILT:
          ev_pcb = (struct kern_event_pcb *) so->so_pcb;
          kev_req->vendor_code = ev_pcb->vendor_code_filter;
          kev_req->kev_class   = ev_pcb->class_filter;
          kev_req->kev_subclass = ev_pcb->subclass_filter;
          break;

     default:
          return EOPNOTSUPP;
     }

     return 0;
}


struct pr_usrreqs event_usrreqs = {
     pru_abort_notsupp, pru_accept_notsupp, kev_attach, pru_bind_notsupp, pru_connect_notsupp,
     pru_connect2_notsupp, kev_control, kev_detach, pru_disconnect_notsupp,
     pru_listen_notsupp, pru_peeraddr_notsupp, pru_rcvd_notsupp, pru_rcvoob_notsupp,
     pru_send_notsupp, pru_sense_null, pru_shutdown_notsupp, pru_sockaddr_notsupp,
     pru_sosend_notsupp, soreceive, sopoll
};