]> git.saurik.com Git - apple/xnu.git/blobdiff - bsd/kern/kern_event.c
xnu-2050.24.15.tar.gz
[apple/xnu.git] / bsd / kern / kern_event.c
index a431f36b257b9549e6d3d05d91b973bfa7a0db37..0e2705e5acf621d0276f1e77b1426ce25de876f0 100644 (file)
 /*
- * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
+ * Copyright (c) 2000-2011 Apple Inc. All rights reserved.
  *
- * @APPLE_LICENSE_HEADER_START@
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
  * 
- * The contents of this file constitute Original Code as defined in and
- * are subject to the Apple Public Source License Version 1.1 (the
- * "License").  You may not use this file except in compliance with the
- * License.  Please obtain a copy of the License at
- * http://www.apple.com/publicsource and read it before using this file.
+ * 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. The rights granted to you under the License
+ * may not be used to create, or enable the creation or redistribution of,
+ * unlawful or unlicensed copies of an Apple operating system, or to
+ * circumvent, violate, or enable the circumvention or violation of, any
+ * terms of an Apple operating system software license agreement.
  * 
- * This Original Code and all software distributed under the License are
- * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * 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 OR NON-INFRINGEMENT.  Please see the
- * License for the specific language governing rights and limitations
- * under the License.
+ * 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@
+ * @APPLE_OSREFERENCE_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 <stdint.h>
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/filedesc.h>
+#include <sys/kernel.h>
+#include <sys/proc_internal.h>
+#include <sys/kauth.h>
+#include <sys/malloc.h> 
+#include <sys/unistd.h>
+#include <sys/file_internal.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 <sys/sysproto.h>
+#include <sys/user.h>
+#include <sys/vnode_internal.h>
+#include <string.h>
+#include <sys/proc_info.h>
+
+#include <kern/lock.h>
+#include <kern/clock.h>
+#include <kern/thread_call.h>
+#include <kern/sched_prim.h>
+#include <kern/zalloc.h>
+#include <kern/assert.h>
+
+#include <libkern/libkern.h>
+#include "net/net_str_id.h"
+
+#include <mach/task.h>
+
+#if VM_PRESSURE_EVENTS
+#include <kern/vm_pressure.h>
+#endif
+
+MALLOC_DEFINE(M_KQUEUE, "kqueue", "memory for kqueue system");
+
+#define KQ_EVENT NULL
+
+static inline void kqlock(struct kqueue *kq);
+static inline void kqunlock(struct kqueue *kq);
+
+static int     kqlock2knoteuse(struct kqueue *kq, struct knote *kn);
+static int     kqlock2knoteusewait(struct kqueue *kq, struct knote *kn);
+static int     kqlock2knotedrop(struct kqueue *kq, struct knote *kn);
+static int     knoteuse2kqlock(struct kqueue *kq, struct knote *kn);
+
+static void    kqueue_wakeup(struct kqueue *kq, int closed);
+static int     kqueue_read(struct fileproc *fp, struct uio *uio,
+                   int flags, vfs_context_t ctx);
+static int     kqueue_write(struct fileproc *fp, struct uio *uio,
+                   int flags, vfs_context_t ctx);
+static int     kqueue_ioctl(struct fileproc *fp, u_long com, caddr_t data,
+                   vfs_context_t ctx);
+static int     kqueue_select(struct fileproc *fp, int which, void *wql, 
+                   vfs_context_t ctx);
+static int     kqueue_close(struct fileglob *fg, vfs_context_t ctx);
+static int     kqueue_kqfilter(struct fileproc *fp, struct knote *kn, vfs_context_t ctx);
+static int     kqueue_drain(struct fileproc *fp, vfs_context_t ctx);
+extern int     kqueue_stat(struct fileproc *fp, void  *ub, int isstat64, vfs_context_t ctx);
+
+static struct fileops kqueueops = {
+       .fo_read = kqueue_read,
+       .fo_write = kqueue_write,
+       .fo_ioctl = kqueue_ioctl,
+       .fo_select = kqueue_select,
+       .fo_close = kqueue_close,
+       .fo_kqfilter = kqueue_kqfilter,
+       .fo_drain = kqueue_drain,
+};
+
+static int kevent_internal(struct proc *p, int iskev64, user_addr_t changelist,
+               int nchanges, user_addr_t eventlist, int nevents, int fd, 
+               user_addr_t utimeout, unsigned int flags, int32_t *retval);
+static int kevent_copyin(user_addr_t *addrp, struct kevent64_s *kevp, struct proc *p, int iskev64);
+static int kevent_copyout(struct kevent64_s *kevp, user_addr_t *addrp, struct proc *p, int iskev64);
+char * kevent_description(struct kevent64_s *kevp, char *s, size_t n);
+
+static int     kevent_callback(struct kqueue *kq, struct kevent64_s *kevp, void *data);
+static void    kevent_continue(struct kqueue *kq, void *data, int error);
+static void    kqueue_scan_continue(void *contp, wait_result_t wait_result);
+static int     kqueue_process(struct kqueue *kq, kevent_callback_t callback,
+                              void *data, int *countp, struct proc *p);
+static int     kqueue_begin_processing(struct kqueue *kq);
+static void    kqueue_end_processing(struct kqueue *kq);
+static int     knote_process(struct knote *kn, kevent_callback_t callback,
+                             void *data, struct kqtailq *inprocessp, struct proc *p);
+static void    knote_put(struct knote *kn);
+static int     knote_fdpattach(struct knote *kn, struct filedesc *fdp, struct proc *p);
+static void    knote_drop(struct knote *kn, struct proc *p);
+static void    knote_activate(struct knote *kn, int);
+static void    knote_deactivate(struct knote *kn);
+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 = {
+        .f_isfd = 1,
+        .f_attach = filt_fileattach,
+};
+
+static void    filt_kqdetach(struct knote *kn);
+static int     filt_kqueue(struct knote *kn, long hint);
+static struct filterops kqread_filtops = {
+        .f_isfd = 1,
+        .f_detach = filt_kqdetach,
+        .f_event = filt_kqueue,
+};
+
+/*
+ * placeholder for not-yet-implemented filters
+ */ 
+static int     filt_badattach(struct knote *kn);
+static struct filterops bad_filtops = {
+        .f_attach = filt_badattach,
+};
+
+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 = {
+        .f_attach = filt_procattach,
+        .f_detach = filt_procdetach,
+        .f_event = filt_proc,
+};
+
+#if VM_PRESSURE_EVENTS
+static int filt_vmattach(struct knote *kn);
+static void filt_vmdetach(struct knote *kn);
+static int filt_vm(struct knote *kn, long hint);
+static struct filterops vm_filtops = {
+       .f_attach = filt_vmattach,
+       .f_detach = filt_vmdetach,
+       .f_event = filt_vm,
+};
+#endif /* VM_PRESSURE_EVENTS */
+
+extern struct filterops fs_filtops;
+
+extern struct filterops sig_filtops;
+
+/* Timer filter */
+static int     filt_timerattach(struct knote *kn);
+static void    filt_timerdetach(struct knote *kn);
+static int     filt_timer(struct knote *kn, long hint);
+static void     filt_timertouch(struct knote *kn, struct kevent64_s *kev, 
+               long type);
+static struct filterops timer_filtops = {
+        .f_attach = filt_timerattach,
+        .f_detach = filt_timerdetach,
+        .f_event = filt_timer,
+        .f_touch = filt_timertouch,
+};
+
+/* Helpers */
+
+static void    filt_timerexpire(void *knx, void *param1);
+static int     filt_timervalidate(struct knote *kn);
+static void    filt_timerupdate(struct knote *kn);
+static void    filt_timercancel(struct knote *kn);
+
+#define TIMER_RUNNING          0x1
+#define TIMER_CANCELWAIT       0x2
+
+static lck_mtx_t _filt_timerlock;
+static void    filt_timerlock(void);
+static void    filt_timerunlock(void);
+
+static zone_t  knote_zone;
+
+#define KN_HASH(val, mask)     (((val) ^ (val >> 8)) & (mask))
+
+#if 0
+extern struct filterops aio_filtops;
+#endif
+
+/* Mach portset filter */
+extern struct filterops machport_filtops;
+
+/* User filter */
+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 kevent64_s *kev, 
+               long type);
+static struct filterops user_filtops = {
+        .f_attach = filt_userattach,
+        .f_detach = filt_userdetach,
+        .f_event = filt_user,
+        .f_touch = filt_usertouch,
+};
+
+/*
+ * 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 */
+       &timer_filtops,                 /* EVFILT_TIMER */
+       &machport_filtops,              /* EVFILT_MACHPORT */
+       &fs_filtops,                    /* EVFILT_FS */
+       &user_filtops,                  /* EVFILT_USER */
+       &bad_filtops,                   /* unused */
+#if VM_PRESSURE_EVENTS
+       &vm_filtops,                    /* EVFILT_VM */
+#else
+       &bad_filtops,                   /* EVFILT_VM */
+#endif
+       &file_filtops,                  /* EVFILT_SOCK */
+};
+
+/*
+ * kqueue/note lock attributes and implementations
+ *
+ *     kqueues have locks, while knotes have use counts
+ *     Most of the knote state is guarded by the object lock.
+ *     the knote "inuse" count and status use the kqueue lock.
+ */
+lck_grp_attr_t * kq_lck_grp_attr;
+lck_grp_t * kq_lck_grp;
+lck_attr_t * kq_lck_attr;
+
+static inline void
+kqlock(struct kqueue *kq)
+{
+       lck_spin_lock(&kq->kq_lock);
+}
+
+static inline void
+kqunlock(struct kqueue *kq)
+{
+       lck_spin_unlock(&kq->kq_lock);
+}
+
+/* 
+ * Convert a kq lock to a knote use referece.
+ *
+ *     If the knote is being dropped, we can't get
+ *     a use reference, so just return with it
+ *     still locked.
+ *     
+ *     - kq locked at entry
+ *     - unlock on exit if we get the use reference
+ */
+static int
+kqlock2knoteuse(struct kqueue *kq, struct knote *kn)
+{
+       if (kn->kn_status & KN_DROPPING)
+               return 0;
+       kn->kn_inuse++;
+       kqunlock(kq);
+       return 1;
+ }
+
+/* 
+ * Convert a kq lock to a knote use referece,
+ * but wait for attach and drop events to complete.
+ *
+ *     If the knote is being dropped, we can't get
+ *     a use reference, so just return with it
+ *     still locked.
+ *     
+ *     - kq locked at entry
+ *     - kq always unlocked on exit
+ */
+static int
+kqlock2knoteusewait(struct kqueue *kq, struct knote *kn)
+{
+       if ((kn->kn_status & (KN_DROPPING | KN_ATTACHING)) != 0) {
+               kn->kn_status |= KN_USEWAIT;
+               wait_queue_assert_wait((wait_queue_t)kq->kq_wqs, &kn->kn_status, THREAD_UNINT, 0);
+               kqunlock(kq);
+               thread_block(THREAD_CONTINUE_NULL);
+               return 0;
+       }
+       kn->kn_inuse++;
+       kqunlock(kq);
+       return 1;
+ }
+
+
+/* 
+ * Convert from a knote use reference back to kq lock.
+ *
+ *     Drop a use reference and wake any waiters if
+ *     this is the last one.
+ *
+ *     The exit return indicates if the knote is
+ *     still alive - but the kqueue lock is taken
+ *     unconditionally.
+ */
+static int
+knoteuse2kqlock(struct kqueue *kq, struct knote *kn)
+{
+       kqlock(kq);
+       if (--kn->kn_inuse == 0) {
+               if ((kn->kn_status & KN_ATTACHING) != 0) {
+                       kn->kn_status &= ~KN_ATTACHING;
+               }
+               if ((kn->kn_status & KN_USEWAIT) != 0) {
+                       kn->kn_status &= ~KN_USEWAIT;
+                       wait_queue_wakeup_all((wait_queue_t)kq->kq_wqs, &kn->kn_status, THREAD_AWAKENED);
+               }
+       }
+       return ((kn->kn_status & KN_DROPPING) == 0);
+ }
+
+/* 
+ * Convert a kq lock to a knote drop referece.
+ *
+ *     If the knote is in use, wait for the use count
+ *     to subside.  We first mark our intention to drop
+ *     it - keeping other users from "piling on."
+ *     If we are too late, we have to wait for the
+ *     other drop to complete.
+ *     
+ *     - kq locked at entry
+ *     - always unlocked on exit.
+ *     - caller can't hold any locks that would prevent
+ *       the other dropper from completing.
+ */
+static int
+kqlock2knotedrop(struct kqueue *kq, struct knote *kn)
+{
+       int oktodrop;
+
+       oktodrop = ((kn->kn_status & (KN_DROPPING | KN_ATTACHING)) == 0);
+       kn->kn_status |= KN_DROPPING;
+       if (oktodrop) {
+               if (kn->kn_inuse == 0) {
+                       kqunlock(kq);
+                       return oktodrop;
+               }
+       }
+       kn->kn_status |= KN_USEWAIT;
+       wait_queue_assert_wait((wait_queue_t)kq->kq_wqs, &kn->kn_status, THREAD_UNINT, 0);
+       kqunlock(kq);
+       thread_block(THREAD_CONTINUE_NULL);
+       return oktodrop;
+}
+               
+/* 
+ * Release a knote use count reference.
+ */
+static void
+knote_put(struct knote *kn)
+{
+       struct kqueue *kq = kn->kn_kq;
+
+       kqlock(kq);
+       if (--kn->kn_inuse == 0) {
+               if ((kn->kn_status & KN_USEWAIT) != 0) {
+                       kn->kn_status &= ~KN_USEWAIT;
+                       wait_queue_wakeup_all((wait_queue_t)kq->kq_wqs, &kn->kn_status, THREAD_AWAKENED);
+               }
+       }
+       kqunlock(kq);
+ }
+
+static int
+filt_fileattach(struct knote *kn)
+{
+       
+       return (fo_kqfilter(kn->kn_fp, kn, vfs_context_current()));
+}
+
+#define f_flag f_fglob->fg_flag
+#define f_type f_fglob->fg_type
+#define f_msgcount f_fglob->fg_msgcount
+#define f_cred f_fglob->fg_cred
+#define f_ops f_fglob->fg_ops
+#define f_offset f_fglob->fg_offset
+#define f_data f_fglob->fg_data
+
+static void
+filt_kqdetach(struct knote *kn)
+{
+       struct kqueue *kq = (struct kqueue *)kn->kn_fp->f_data;
+
+       kqlock(kq);
+       KNOTE_DETACH(&kq->kq_sel.si_note, kn);
+       kqunlock(kq);
+}
+
+/*ARGSUSED*/
+static int
+filt_kqueue(struct knote *kn, __unused 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;
+
+       assert(PID_MAX < NOTE_PDATAMASK);
+       
+       if ((kn->kn_sfflags & (NOTE_TRACK | NOTE_TRACKERR | NOTE_CHILD)) != 0)
+               return(ENOTSUP);
+
+       p = proc_find(kn->kn_id);
+       if (p == NULL) {
+               return (ESRCH);
+       }
+
+       const int NoteExitStatusBits = NOTE_EXIT | NOTE_EXITSTATUS;
+
+       if ((kn->kn_sfflags & NoteExitStatusBits) == NoteExitStatusBits)
+               do {
+                       pid_t selfpid = proc_selfpid();
+
+                       if (p->p_ppid == selfpid)
+                               break;  /* parent => ok */
+
+                       if ((p->p_lflag & P_LTRACED) != 0 &&
+                           (p->p_oppid == selfpid))
+                               break;  /* parent-in-waiting => ok */
+
+                       proc_rele(p);
+                       return (EACCES);
+               } while (0);
+
+       proc_klist_lock();
+
+       kn->kn_flags |= EV_CLEAR;       /* automatically set */
+       kn->kn_ptr.p_proc = p;          /* store the proc handle */
+
+       KNOTE_ATTACH(&p->p_klist, kn);
+
+       proc_klist_unlock();
+
+       proc_rele(p);
+
+       return (0);
+}
+
+/*
+ * The knote may be attached to a different process, which may exit,
+ * leaving nothing for the knote to be attached to.  In that case,
+ * the pointer to the process will have already been nulled out.
+ */
+static void
+filt_procdetach(struct knote *kn)
+{
+       struct proc *p;
+
+       proc_klist_lock();
+       
+       p = kn->kn_ptr.p_proc;
+       if (p != PROC_NULL) {
+               kn->kn_ptr.p_proc = PROC_NULL;
+               KNOTE_DETACH(&p->p_klist, kn);
+       }
+
+       proc_klist_unlock();
+}
+
+static int
+filt_proc(struct knote *kn, long hint)
+{
+       /* hint is 0 when called from above */
+       if (hint != 0) {
+               u_int event;
+
+               /* ALWAYS CALLED WITH proc_klist_lock when (hint != 0) */
+
+               /*
+                * mask off extra data
+                */
+               event = (u_int)hint & NOTE_PCTRLMASK;
+
+               /*
+                * termination lifecycle events can happen while a debugger
+                * has reparented a process, in which case notifications
+                * should be quashed except to the tracing parent. When
+                * the debugger reaps the child (either via wait4(2) or
+                * process exit), the child will be reparented to the original
+                * parent and these knotes re-fired.
+                */
+               if (event & NOTE_EXIT) {
+                       if ((kn->kn_ptr.p_proc->p_oppid != 0)
+                               && (kn->kn_kq->kq_p->p_pid != kn->kn_ptr.p_proc->p_ppid)) {
+                               /*
+                                * This knote is not for the current ptrace(2) parent, ignore.
+                                */
+                               return 0;
+                       }
+               }                                       
+
+               /*
+                * if the user is interested in this event, record it.
+                */
+               if (kn->kn_sfflags & event)
+                       kn->kn_fflags |= event;
+
+               if (event == NOTE_REAP || (event == NOTE_EXIT && !(kn->kn_sfflags & NOTE_REAP))) {
+                       kn->kn_flags |= (EV_EOF | EV_ONESHOT);
+               }
+               if ((event == NOTE_EXIT) && ((kn->kn_sfflags & NOTE_EXITSTATUS) != 0)) {
+                       kn->kn_fflags |= NOTE_EXITSTATUS;
+                       kn->kn_data = (hint & NOTE_PDATAMASK);
+               }
+               if ((event == NOTE_RESOURCEEND) && ((kn->kn_sfflags & NOTE_RESOURCEEND) != 0)) {
+                       kn->kn_fflags |= NOTE_RESOURCEEND;
+                       kn->kn_data = (hint & NOTE_PDATAMASK);
+               }
+#if CONFIG_EMBEDDED
+               /* If the event is one of the APPSTATE events,remove the rest */
+               if (((event & NOTE_APPALLSTATES) != 0) && ((kn->kn_sfflags & NOTE_APPALLSTATES) != 0)) {
+                       /* only one state at a time */
+                       kn->kn_fflags &= ~NOTE_APPALLSTATES;
+                       kn->kn_fflags |= event;
+               }
+#endif /* CONFIG_EMBEDDED */
+       }
+
+       /* atomic check, no locking need when called from above */
+       return (kn->kn_fflags != 0); 
+}
+
+#if VM_PRESSURE_EVENTS
+/*
+ * Virtual memory kevents
+ *
+ * author: Matt Jacobson [matthew_jacobson@apple.com]
+ */
+
+static int
+filt_vmattach(struct knote *kn)
+{      
+       /* 
+        * The note will be cleared once the information has been flushed to the client. 
+        * If there is still pressure, we will be re-alerted.
+        */
+       kn->kn_flags |= EV_CLEAR; 
+       
+       return vm_knote_register(kn);
+}
+
+static void
+filt_vmdetach(struct knote *kn)
+{
+       vm_knote_unregister(kn);
+}
+
+static int
+filt_vm(struct knote *kn, long hint)
+{
+       /* hint == 0 means this is just an alive? check (always true) */
+       if (hint != 0) { 
+               const pid_t pid = (pid_t)hint;
+               if ((kn->kn_sfflags & NOTE_VM_PRESSURE) && (kn->kn_kq->kq_p->p_pid == pid)) {
+                       kn->kn_fflags |= NOTE_VM_PRESSURE;
+               }
+       }
+       
+       return (kn->kn_fflags != 0);
+}
+#endif /* VM_PRESSURE_EVENTS */
+
+/*
+ * filt_timervalidate - process data from user
+ *     
+ *     Converts to either interval or deadline format.
+ *     
+ *     The saved-data field in the knote contains the
+ *     time value.  The saved filter-flags indicates
+ *     the unit of measurement.
+ *
+ *     After validation, either the saved-data field 
+ *     contains the interval in absolute time, or ext[0] 
+ *     contains the expected deadline. If that deadline 
+ *     is in the past, ext[0] is 0.
+ *
+ *     Returns EINVAL for unrecognized units of time.
+ *
+ *     Timer filter lock is held.
+ *
+ */
+static int
+filt_timervalidate(struct knote *kn)
+{
+       uint64_t multiplier;
+       uint64_t raw;
+
+       switch (kn->kn_sfflags & (NOTE_SECONDS|NOTE_USECONDS|NOTE_NSECONDS)) {
+       case NOTE_SECONDS:
+               multiplier = NSEC_PER_SEC;
+               break;
+       case NOTE_USECONDS:
+               multiplier = NSEC_PER_USEC;
+               break;
+       case NOTE_NSECONDS:
+               multiplier = 1;
+               break;
+       case 0: /* milliseconds (default) */
+               multiplier = NSEC_PER_SEC / 1000;
+               break;
+       default:
+               return EINVAL;
+       }
+
+       nanoseconds_to_absolutetime((uint64_t)kn->kn_sdata * multiplier, &raw);
+
+       kn->kn_ext[0] = 0;
+       kn->kn_sdata = 0;
+
+       if (kn->kn_sfflags & NOTE_ABSOLUTE) {
+               clock_sec_t seconds;
+               clock_nsec_t nanoseconds;
+               uint64_t now;
+
+               clock_get_calendar_nanotime(&seconds, &nanoseconds);
+               nanoseconds_to_absolutetime((uint64_t)seconds * NSEC_PER_SEC + 
+                               nanoseconds, &now);
+
+               if (raw < now) {
+                       /* time has already passed */
+                       kn->kn_ext[0] = 0;
+               } else {
+                       raw -= now;
+                       clock_absolutetime_interval_to_deadline(raw, 
+                                       &kn->kn_ext[0]);
+               }
+       } else {
+               kn->kn_sdata = raw;
+       }
+
+       return 0;
+}
+
+/*
+ * filt_timerupdate - compute the next deadline
+ *
+ *     Repeating timers store their interval in kn_sdata. Absolute
+ *     timers have already calculated the deadline, stored in ext[0].
+ *
+ *     On return, the next deadline (or zero if no deadline is needed)
+ *     is stored in kn_ext[0].
+ *
+ *     Timer filter lock is held.
+ */
+static void 
+filt_timerupdate(struct knote *kn)
+{
+       /* if there's no interval, deadline is just in kn_ext[0] */
+       if (kn->kn_sdata == 0)
+               return;
+
+       /* if timer hasn't fired before, fire in interval nsecs */
+       if (kn->kn_ext[0] == 0) {
+               clock_absolutetime_interval_to_deadline(kn->kn_sdata,
+                               &kn->kn_ext[0]);
+       } else {
+               /* 
+                * If timer has fired before, schedule the next pop 
+                * relative to the last intended deadline. 
+                *
+                * We could check for whether the deadline has expired, 
+                * but the thread call layer can handle that.
+                */
+               kn->kn_ext[0] += kn->kn_sdata;
+       }
+}
+
+/* 
+ * filt_timerexpire - the timer callout routine
+ *
+ *     Just propagate the timer event into the knote
+ *     filter routine (by going through the knote
+ *     synchronization point).  Pass a hint to
+ *     indicate this is a real event, not just a
+ *     query from above.
+ */
+static void
+filt_timerexpire(void *knx, __unused void *spare)
+{
+       struct klist timer_list;
+       struct knote *kn = knx;
+
+       filt_timerlock();
+
+       kn->kn_hookid &= ~TIMER_RUNNING;
+
+       /* no "object" for timers, so fake a list */
+       SLIST_INIT(&timer_list);
+       SLIST_INSERT_HEAD(&timer_list, kn, kn_selnext); 
+       KNOTE(&timer_list, 1);
+
+       /* if someone is waiting for timer to pop */
+       if (kn->kn_hookid & TIMER_CANCELWAIT) {
+               struct kqueue *kq = kn->kn_kq;
+               wait_queue_wakeup_all((wait_queue_t)kq->kq_wqs, &kn->kn_hook, 
+                               THREAD_AWAKENED);
+       }
+
+       filt_timerunlock();
+}
+
+/*
+ * Cancel a running timer (or wait for the pop).
+ * Timer filter lock is held.
+ */
+static void
+filt_timercancel(struct knote *kn)
+{
+       struct kqueue *kq = kn->kn_kq;
+       thread_call_t callout = kn->kn_hook;
+       boolean_t cancelled;
+
+       if (kn->kn_hookid & TIMER_RUNNING) {
+               /* cancel the callout if we can */
+               cancelled = thread_call_cancel(callout);
+               if (cancelled) {
+                       kn->kn_hookid &= ~TIMER_RUNNING;
+               } else {
+                       /* we have to wait for the expire routine.  */
+                       kn->kn_hookid |= TIMER_CANCELWAIT;
+                       wait_queue_assert_wait((wait_queue_t)kq->kq_wqs, 
+                                       &kn->kn_hook, THREAD_UNINT, 0);
+                       filt_timerunlock();
+                       thread_block(THREAD_CONTINUE_NULL);
+                       filt_timerlock();
+                       assert((kn->kn_hookid & TIMER_RUNNING) == 0);
+               }
+       }
+}
+
+/*
+ * Allocate a thread call for the knote's lifetime, and kick off the timer.
+ */ 
+static int
+filt_timerattach(struct knote *kn)
+{
+       thread_call_t callout;
+       int error;
+
+       callout = thread_call_allocate(filt_timerexpire, kn);
+       if (NULL == callout)
+               return (ENOMEM);
+
+       filt_timerlock();
+       error = filt_timervalidate(kn);
+       if (error) {
+               filt_timerunlock();
+               return (error);
+       }
+
+       kn->kn_hook = (void*)callout;
+       kn->kn_hookid = 0;
+
+       /* absolute=EV_ONESHOT */
+       if (kn->kn_sfflags & NOTE_ABSOLUTE)
+               kn->kn_flags |= EV_ONESHOT; 
+
+       filt_timerupdate(kn);
+       if (kn->kn_ext[0]) {
+               kn->kn_flags |= EV_CLEAR;
+               thread_call_enter_delayed(callout, kn->kn_ext[0]);
+               kn->kn_hookid |= TIMER_RUNNING;
+       } else {
+               /* fake immediate */
+               kn->kn_data = 1;
+       }
+
+       filt_timerunlock();
+       return (0);
+}
+
+/*
+ * Shut down the timer if it's running, and free the callout.
+ */
+static void
+filt_timerdetach(struct knote *kn)
+{
+       thread_call_t callout;
+
+       filt_timerlock();
+
+       callout = (thread_call_t)kn->kn_hook;
+       filt_timercancel(kn);
+       
+       filt_timerunlock(); 
+
+       thread_call_free(callout);
+}
+
+
+
+static int
+filt_timer(struct knote *kn, long hint)
+{
+       int result;
+       
+       if (hint) {
+               /* real timer pop -- timer lock held by filt_timerexpire */
+
+               kn->kn_data++;
+
+               if (((kn->kn_hookid & TIMER_CANCELWAIT) == 0) && 
+                               ((kn->kn_flags & EV_ONESHOT) == 0)) {
+
+                       /* evaluate next time to fire */
+                       filt_timerupdate(kn);
+
+                       if (kn->kn_ext[0]) {
+                               /* keep the callout and re-arm */
+                               thread_call_enter_delayed(kn->kn_hook, 
+                                               kn->kn_ext[0]);
+                               kn->kn_hookid |= TIMER_RUNNING;
+                       }
+               }
+
+               return 1;
+       } 
+
+       /* user-query */
+       filt_timerlock();
+
+       result = (kn->kn_data != 0);
+
+       filt_timerunlock();
+       return result;
+}
+
+
+/*
+ * filt_timertouch - update knote with new user input
+ *
+ *     Cancel and restart the timer based on new user data. When
+ *     the user picks up a knote, clear the count of how many timer
+ *     pops have gone off (in kn_data).
+ */
+static void     
+filt_timertouch(struct knote *kn, struct kevent64_s *kev, long type)
+{
+       int error;
+       filt_timerlock();
+
+       switch (type) {
+       case EVENT_REGISTER:
+               /* cancel current call */
+               filt_timercancel(kn);
+
+               /* recalculate deadline */
+               kn->kn_sdata = kev->data;
+               kn->kn_sfflags = kev->fflags;
+
+               error = filt_timervalidate(kn);
+               if (error) {
+                       /* no way to report error, so mark it in the knote */
+                       kn->kn_flags |= EV_ERROR;
+                       kn->kn_data = error;
+                       break;
+               } 
+
+               /* start timer if necessary */
+               filt_timerupdate(kn);
+               if (kn->kn_ext[0]) {
+                       thread_call_enter_delayed(kn->kn_hook, kn->kn_ext[0]);
+                       kn->kn_hookid |= TIMER_RUNNING;
+               } else {
+                       /* pretend the timer has fired */
+                       kn->kn_data = 1;
+               }
+
+               break;
+
+       case EVENT_PROCESS:
+               /* reset the timer pop count in kn_data */
+               *kev = kn->kn_kevent;
+               kev->ext[0] = 0;
+               kn->kn_data = 0;
+               if (kn->kn_flags & EV_CLEAR)
+                       kn->kn_fflags = 0;
+               break;
+       default:
+               panic("filt_timertouch() - invalid type (%ld)", type);
+               break;
+       }
+
+       filt_timerunlock();
+}
+
+static void
+filt_timerlock(void)
+{
+       lck_mtx_lock(&_filt_timerlock);
+}
+
+static void
+filt_timerunlock(void)
+{
+       lck_mtx_unlock(&_filt_timerlock);
+}
+
+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 kevent64_s *kev, long type)
+{
+        uint32_t 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:
+                        OSBitAndAtomic(kev->fflags, &kn->kn_sfflags);
+                        break;
+                case NOTE_FFOR:
+                        OSBitOrAtomic(kev->fflags, &kn->kn_sfflags);
+                        break;
+                case NOTE_FFCOPY:
+                        kn->kn_sfflags = kev->fflags;
+                        break;
+                }
+                kn->kn_sdata = kev->data;
+                break;
+        case EVENT_PROCESS:
+                *kev = kn->kn_kevent;
+                kev->fflags = (volatile UInt32)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;
+        }
+}
+
+/*
+ * JMM - placeholder for not-yet-implemented filters
+ */ 
+static int
+filt_badattach(__unused struct knote *kn)
+{
+       return(ENOTSUP);
+}
+
+
+struct kqueue *
+kqueue_alloc(struct proc *p)
+{
+       struct filedesc *fdp = p->p_fd;
+       struct kqueue *kq;
+
+       MALLOC_ZONE(kq, struct kqueue *, sizeof(struct kqueue), M_KQUEUE, M_WAITOK);
+       if (kq != NULL) {
+               wait_queue_set_t wqs;
+
+               wqs = wait_queue_set_alloc(SYNC_POLICY_FIFO | SYNC_POLICY_PREPOST);
+               if (wqs != NULL) {
+                       bzero(kq, sizeof(struct kqueue));
+                       lck_spin_init(&kq->kq_lock, kq_lck_grp, kq_lck_attr);
+                       TAILQ_INIT(&kq->kq_head);
+                       kq->kq_wqs = wqs;
+                       kq->kq_p = p;
+               } else {
+                       FREE_ZONE(kq, sizeof(struct kqueue), M_KQUEUE);
+               }
+       }
+
+       if (fdp->fd_knlistsize < 0) {
+               proc_fdlock(p);
+               if (fdp->fd_knlistsize < 0)
+                       fdp->fd_knlistsize = 0;         /* this process has had a kq */
+               proc_fdunlock(p);
+       }
+
+       return kq;
+}
+
+
+/*
+ * kqueue_dealloc - detach all knotes from a kqueue and free it
+ *
+ *     We walk each list looking for knotes referencing this
+ *     this kqueue.  If we find one, we try to drop it.  But
+ *     if we fail to get a drop reference, that will wait
+ *     until it is dropped.  So, we can just restart again
+ *     safe in the assumption that the list will eventually
+ *     not contain any more references to this kqueue (either
+ *     we dropped them all, or someone else did).
+ *
+ *     Assumes no new events are being added to the kqueue.
+ *     Nothing locked on entry or exit.
+ */
+void
+kqueue_dealloc(struct kqueue *kq)
+{
+       struct proc *p = kq->kq_p;
+       struct filedesc *fdp = p->p_fd;
+       struct knote *kn;
+       int i;
+
+       proc_fdlock(p);
+       for (i = 0; i < fdp->fd_knlistsize; i++) {
+               kn = SLIST_FIRST(&fdp->fd_knlist[i]);
+               while (kn != NULL) {
+                       if (kq == kn->kn_kq) {
+                               kqlock(kq);
+                               proc_fdunlock(p);
+                               /* drop it ourselves or wait */
+                               if (kqlock2knotedrop(kq, kn)) {
+                                       kn->kn_fop->f_detach(kn);
+                                       knote_drop(kn, p);
+                               }
+                               proc_fdlock(p);
+                               /* start over at beginning of list */
+                               kn = SLIST_FIRST(&fdp->fd_knlist[i]);
+                               continue;
+                       }
+                       kn = SLIST_NEXT(kn, kn_link);
+               }
+       }
+       if (fdp->fd_knhashmask != 0) {
+               for (i = 0; i < (int)fdp->fd_knhashmask + 1; i++) {
+                       kn = SLIST_FIRST(&fdp->fd_knhash[i]);
+                       while (kn != NULL) {
+                               if (kq == kn->kn_kq) {
+                                       kqlock(kq);
+                                       proc_fdunlock(p);
+                                       /* drop it ourselves or wait */
+                                       if (kqlock2knotedrop(kq, kn)) {
+                                               kn->kn_fop->f_detach(kn);
+                                               knote_drop(kn, p);
+                                       }
+                                       proc_fdlock(p);
+                                       /* start over at beginning of list */
+                                       kn = SLIST_FIRST(&fdp->fd_knhash[i]);
+                                       continue;
+                               }
+                               kn = SLIST_NEXT(kn, kn_link);
+                       }
+               }
+       }
+       proc_fdunlock(p);
+
+       /* 
+        * before freeing the wait queue set for this kqueue,
+        * make sure it is unlinked from all its containing (select) sets.
+        */
+       wait_queue_unlink_all((wait_queue_t)kq->kq_wqs);
+       wait_queue_set_free(kq->kq_wqs);
+       lck_spin_destroy(&kq->kq_lock, kq_lck_grp);
+       FREE_ZONE(kq, sizeof(struct kqueue), M_KQUEUE);
+}
+
+int
+kqueue(struct proc *p, __unused struct kqueue_args *uap, int32_t *retval)
+{
+       struct kqueue *kq;
+       struct fileproc *fp;
+       int fd, error;
+
+       error = falloc(p, &fp, &fd, vfs_context_current());
+       if (error) {
+               return (error);
+       }
+
+       kq = kqueue_alloc(p);
+       if (kq == NULL) {
+               fp_free(p, fd, fp);
+               return (ENOMEM);
+       }
+
+       fp->f_flag = FREAD | FWRITE;
+       fp->f_type = DTYPE_KQUEUE;
+       fp->f_ops = &kqueueops;
+       fp->f_data = (caddr_t)kq;
+
+       proc_fdlock(p);
+       procfdtbl_releasefd(p, fd, NULL);
+       fp_drop(p, fd, fp, 1);
+       proc_fdunlock(p);
+
+       *retval = fd;
+       return (error);
+}
+
+static int
+kevent_copyin(user_addr_t *addrp, struct kevent64_s *kevp, struct proc *p, int iskev64)
+{
+       int advance;
+       int error;
+
+       if (iskev64) {
+               advance = sizeof(struct kevent64_s);
+               error = copyin(*addrp, (caddr_t)kevp, advance);
+       } else if (IS_64BIT_PROCESS(p)) {
+               struct user64_kevent kev64;
+               bzero(kevp, sizeof(struct kevent64_s));
+
+               advance = sizeof(kev64);
+               error = copyin(*addrp, (caddr_t)&kev64, advance);
+               if (error)
+                       return error;
+               kevp->ident = kev64.ident;
+               kevp->filter = kev64.filter;
+               kevp->flags = kev64.flags;
+               kevp->fflags = kev64.fflags;
+               kevp->data = kev64.data;
+               kevp->udata = kev64.udata;
+       } else {
+               struct user32_kevent kev32;
+               bzero(kevp, sizeof(struct kevent64_s));
+
+               advance = sizeof(kev32);
+               error = copyin(*addrp, (caddr_t)&kev32, advance);
+               if (error)
+                       return error;
+               kevp->ident = (uintptr_t)kev32.ident;
+               kevp->filter = kev32.filter;
+               kevp->flags = kev32.flags;
+               kevp->fflags = kev32.fflags;
+               kevp->data = (intptr_t)kev32.data;
+               kevp->udata = CAST_USER_ADDR_T(kev32.udata);
+       }
+       if (!error)
+               *addrp += advance;
+       return error;
+}
+
+static int
+kevent_copyout(struct kevent64_s *kevp, user_addr_t *addrp, struct proc *p, int iskev64)
+{
+       int advance;
+       int error;
+
+       if (iskev64) {
+               advance = sizeof(struct kevent64_s);
+               error = copyout((caddr_t)kevp, *addrp, advance);
+       } else if (IS_64BIT_PROCESS(p)) {
+               struct user64_kevent kev64;
+
+               /*
+                * deal with the special case of a user-supplied
+                * value of (uintptr_t)-1.
+                */
+               kev64.ident = (kevp->ident == (uintptr_t)-1) ?
+                          (uint64_t)-1LL : (uint64_t)kevp->ident;
+
+               kev64.filter = kevp->filter;
+               kev64.flags = kevp->flags;
+               kev64.fflags = kevp->fflags;
+               kev64.data = (int64_t) kevp->data;
+               kev64.udata = kevp->udata;
+               advance = sizeof(kev64);
+               error = copyout((caddr_t)&kev64, *addrp, advance);
+       } else {
+               struct user32_kevent kev32;
+
+               kev32.ident = (uint32_t)kevp->ident;
+               kev32.filter = kevp->filter;
+               kev32.flags = kevp->flags;
+               kev32.fflags = kevp->fflags;
+               kev32.data = (int32_t)kevp->data;
+               kev32.udata = kevp->udata;
+               advance = sizeof(kev32);
+               error = copyout((caddr_t)&kev32, *addrp, advance);
+       }
+       if (!error)
+               *addrp += advance;
+       return error;
+}
+
+/*
+ * kevent_continue - continue a kevent syscall after blocking
+ *
+ *     assume we inherit a use count on the kq fileglob.
+ */
+
+static void
+kevent_continue(__unused struct kqueue *kq, void *data, int error)
+{
+       struct _kevent *cont_args;
+       struct fileproc *fp;
+       int32_t *retval;
+       int noutputs;
+       int fd;
+       struct proc *p = current_proc();
+
+       cont_args = (struct _kevent *)data;
+       noutputs = cont_args->eventout;
+       retval = cont_args->retval;
+       fd = cont_args->fd;
+       fp = cont_args->fp;
+
+       fp_drop(p, fd, fp, 0);
+
+       /* don't restart after signals... */
+       if (error == ERESTART)
+               error = EINTR;
+       else if (error == EWOULDBLOCK)
+               error = 0;
+       if (error == 0)
+               *retval = noutputs;
+       unix_syscall_return(error);
+}
+
+/*
+ * kevent - [syscall] register and wait for kernel events
+ *
+ */
+int
+kevent(struct proc *p, struct kevent_args *uap, int32_t *retval)
+{
+       return kevent_internal(p, 
+                       0, 
+                       uap->changelist,
+                       uap->nchanges,
+                       uap->eventlist,
+                       uap->nevents,
+                       uap->fd,
+                       uap->timeout,
+                       0, /* no flags from old kevent() call */
+                       retval);
+}
+  
+int
+kevent64(struct proc *p, struct kevent64_args *uap, int32_t *retval)
+{
+       return kevent_internal(p, 
+                       1, 
+                       uap->changelist,
+                       uap->nchanges,
+                       uap->eventlist,
+                       uap->nevents,
+                       uap->fd,
+                       uap->timeout,
+                       uap->flags,
+                       retval);
+}
+
+static int
+kevent_internal(struct proc *p, int iskev64, user_addr_t changelist, 
+               int nchanges, user_addr_t ueventlist, int nevents, int fd, 
+               user_addr_t utimeout, __unused unsigned int flags, 
+               int32_t *retval)
+{
+       struct _kevent *cont_args;
+       uthread_t ut;
+       struct kqueue *kq;
+       struct fileproc *fp;
+       struct kevent64_s kev;
+       int error, noutputs;
+       struct timeval atv;
+
+       /* convert timeout to absolute - if we have one */
+       if (utimeout != USER_ADDR_NULL) {
+               struct timeval rtv;
+               if (IS_64BIT_PROCESS(p)) {
+                       struct user64_timespec ts;
+                       error = copyin(utimeout, &ts, sizeof(ts));
+                       if ((ts.tv_sec & 0xFFFFFFFF00000000ull) != 0)
+                               error = EINVAL;
+                       else
+                               TIMESPEC_TO_TIMEVAL(&rtv, &ts);
+               } else {
+                       struct user32_timespec ts;
+                       error = copyin(utimeout, &ts, sizeof(ts));
+                       TIMESPEC_TO_TIMEVAL(&rtv, &ts);
+               }
+               if (error)
+                       return error;
+               if (itimerfix(&rtv))
+                       return EINVAL;
+               getmicrouptime(&atv);
+               timevaladd(&atv, &rtv);
+       } else {
+               atv.tv_sec = 0;
+               atv.tv_usec = 0;
+       }
+
+       /* get a usecount for the kq itself */
+       if ((error = fp_getfkq(p, fd, &fp, &kq)) != 0)
+               return(error);
+       
+       /* each kq should only be used for events of one type */
+       kqlock(kq);
+       if (kq->kq_state & (KQ_KEV32 | KQ_KEV64)) {
+               if (((iskev64 && (kq->kq_state & KQ_KEV32)) ||
+                       (!iskev64 && (kq->kq_state & KQ_KEV64)))) {
+                       error = EINVAL;
+                       kqunlock(kq);
+                       goto errorout;
+               }
+       } else {
+               kq->kq_state |= (iskev64 ? KQ_KEV64 : KQ_KEV32);
+       }
+       kqunlock(kq);
+
+       /* register all the change requests the user provided... */
+       noutputs = 0;
+       while (nchanges > 0 && error == 0) {
+               error = kevent_copyin(&changelist, &kev, p, iskev64);
+               if (error)
+                       break;
+                               
+               kev.flags &= ~EV_SYSFLAGS;
+               error = kevent_register(kq, &kev, p);
+               if ((error || (kev.flags & EV_RECEIPT)) && nevents > 0) {
+                       kev.flags = EV_ERROR;
+                       kev.data = error;
+                       error = kevent_copyout(&kev, &ueventlist, p, iskev64);
+                       if (error == 0) {
+                               nevents--;
+                               noutputs++;
+                       }
+               }
+               nchanges--;
+       }
+
+       /* store the continuation/completion data in the uthread */
+       ut = (uthread_t)get_bsdthread_info(current_thread());
+       cont_args = &ut->uu_kevent.ss_kevent;
+       cont_args->fp = fp;
+       cont_args->fd = fd;
+       cont_args->retval = retval;
+       cont_args->eventlist = ueventlist;
+       cont_args->eventcount = nevents;
+       cont_args->eventout = noutputs;
+       cont_args->eventsize = iskev64;
+
+       if (nevents > 0 && noutputs == 0 && error == 0)
+               error = kqueue_scan(kq, kevent_callback,
+                                   kevent_continue, cont_args,
+                                   &atv, p);
+       kevent_continue(kq, cont_args, error);
+
+errorout:
+       fp_drop(p, fd, fp, 0);
+       return error;
+}
+
+
+/*
+ * kevent_callback - callback for each individual event
+ *
+ *     called with nothing locked
+ *     caller holds a reference on the kqueue
+ */
+
+static int
+kevent_callback(__unused struct kqueue *kq, struct kevent64_s *kevp, 
+               void *data)
+{
+       struct _kevent *cont_args;
+       int error;
+       int iskev64;
+
+       cont_args = (struct _kevent *)data;
+       assert(cont_args->eventout < cont_args->eventcount);
+
+       iskev64 = cont_args->eventsize;
+
+       /*
+        * Copy out the appropriate amount of event data for this user.
+        */
+       error = kevent_copyout(kevp, &cont_args->eventlist, current_proc(), iskev64);
+
+       /*
+        * If there isn't space for additional events, return
+        * a harmless error to stop the processing here
+        */
+       if (error == 0 && ++cont_args->eventout == cont_args->eventcount)
+                       error = EWOULDBLOCK;
+       return error;
+}
+
+/*
+ * kevent_description - format a description of a kevent for diagnostic output
+ *
+ *      called with a 128-byte string buffer
+ */
+
+char *
+kevent_description(struct kevent64_s *kevp, char *s, size_t n)
+{
+        snprintf(s, n,
+                 "kevent="
+                 "{.ident=%#llx, .filter=%d, .flags=%#x, .fflags=%#x, .data=%#llx, .udata=%#llx, .ext[0]=%#llx, .ext[1]=%#llx}",
+                 kevp->ident,
+                 kevp->filter,
+                 kevp->flags,
+                 kevp->fflags,
+                 kevp->data,
+                 kevp->udata,
+                kevp->ext[0],
+                kevp->ext[1]);
+        return s;
+}
+
+/*
+ * kevent_register - add a new event to a kqueue
+ *
+ *     Creates a mapping between the event source and
+ *     the kqueue via a knote data structure.
+ *
+ *     Because many/most the event sources are file
+ *     descriptor related, the knote is linked off
+ *     the filedescriptor table for quick access.
+ *
+ *     called with nothing locked
+ *     caller holds a reference on the kqueue
+ */
+
+int
+kevent_register(struct kqueue *kq, struct kevent64_s *kev, __unused struct proc *ctxp)
+{
+       struct proc *p = kq->kq_p;
+       struct filedesc *fdp = p->p_fd;
+       struct filterops *fops;
+       struct fileproc *fp = NULL;
+       struct knote *kn = NULL;
+       int 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);
+       }
+
+ restart:
+       /* this iocount needs to be dropped if it is not registered */
+       proc_fdlock(p);
+       if (fops->f_isfd && (error = fp_lookup(p, kev->ident, &fp, 1)) != 0) {
+               proc_fdunlock(p);
+               return(error);
+       }
+
+       if (fops->f_isfd) {
+               /* fd-based knotes are linked off the fd table */
+               if (kev->ident < (u_int)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 {
+               /* hash non-fd knotes here too */
+               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;
+               }
+       }
+
+       /*
+        * kn now contains the matching knote, or NULL if no match
+        */
+       if (kn == NULL) {
+               if ((kev->flags & (EV_ADD|EV_DELETE)) == EV_ADD) {
+                       kn = knote_alloc();
+                       if (kn == NULL) {
+                               proc_fdunlock(p);
+                               error = ENOMEM;
+                               goto done;
+                       }
+                       kn->kn_fp = fp;
+                       kn->kn_kq = kq;
+                       kn->kn_tq = &kq->kq_head;
+                       kn->kn_fop = fops;
+                       kn->kn_sfflags = kev->fflags;
+                       kn->kn_sdata = kev->data;
+                       kev->fflags = 0;
+                       kev->data = 0;
+                       kn->kn_kevent = *kev;
+                       kn->kn_inuse = 1;  /* for f_attach() */
+                       kn->kn_status = KN_ATTACHING;
+
+                       /* before anyone can find it */
+                       if (kev->flags & EV_DISABLE)
+                               kn->kn_status |= KN_DISABLED;
+
+                       error = knote_fdpattach(kn, fdp, p);
+                       proc_fdunlock(p);
+
+                       if (error) {
+                               knote_free(kn);
+                               goto done;
+                       }
+
+                       /*
+                        * apply reference count to knote structure, and
+                        * do not release it at the end of this routine.
+                        */
+                       fp = NULL;
+
+                       error = fops->f_attach(kn);
+
+                       kqlock(kq);
+
+                       if (error != 0) {
+                               /*
+                                * Failed to attach correctly, so drop.
+                                * All other possible users/droppers
+                                * have deferred to us.
+                                */
+                               kn->kn_status |= KN_DROPPING;
+                               kqunlock(kq);
+                               knote_drop(kn, p);
+                               goto done;
+                       } else if (kn->kn_status & KN_DROPPING) {
+                               /*
+                                * Attach succeeded, but someone else
+                                * deferred their drop - now we have
+                                * to do it for them (after detaching).
+                                */
+                               kqunlock(kq);
+                               kn->kn_fop->f_detach(kn);
+                               knote_drop(kn, p);
+                               goto done;
+                       }
+                       kn->kn_status &= ~KN_ATTACHING;
+                       kqunlock(kq);
+               } else {
+                       proc_fdunlock(p);
+                       error = ENOENT;
+                       goto done;
+               }
+       } else {
+               /* existing knote - get kqueue lock */
+               kqlock(kq);
+               proc_fdunlock(p);
+               
+               if (kev->flags & EV_DELETE) {
+                       knote_dequeue(kn);
+                       kn->kn_status |= KN_DISABLED;
+                       if (kqlock2knotedrop(kq, kn)) {
+                               kn->kn_fop->f_detach(kn);
+                               knote_drop(kn, p);
+                       }
+                       goto done;
+               }
+                       
+               /* update status flags for existing knote */
+               if (kev->flags & EV_DISABLE) {
+                       knote_dequeue(kn);
+                       kn->kn_status |= KN_DISABLED;
+               } else if (kev->flags & EV_ENABLE) {
+                       kn->kn_status &= ~KN_DISABLED;
+                       if (kn->kn_status & KN_ACTIVE)
+                               knote_enqueue(kn);
+               }
+
+               /*
+                * 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_kevent.udata = kev->udata;
+               if (fops->f_isfd || fops->f_touch == NULL) {
+                       kn->kn_sfflags = kev->fflags;
+                       kn->kn_sdata = kev->data;
+               }
+
+               /*
+                * If somebody is in the middle of dropping this
+                * knote - go find/insert a new one.  But we have
+                * wait for this one to go away first. Attaches
+                * running in parallel may also drop/modify the
+                * knote.  Wait for those to complete as well and
+                * then start over if we encounter one.
+                */
+               if (!kqlock2knoteusewait(kq, kn)) {
+                       /* kqueue, proc_fdlock both unlocked */
+                       goto restart;
+               }
+
+               /*
+                * Call touch routine to notify filter of changes
+                * in filter values.
+                */
+               if (!fops->f_isfd && fops->f_touch != NULL)
+                       fops->f_touch(kn, kev, EVENT_REGISTER);
+       }
+       /* still have use ref on knote */
+
+       /*
+        * If the knote is not marked to always stay enqueued,
+        * invoke the filter routine to see if it should be
+        * enqueued now.
+        */
+       if ((kn->kn_status & KN_STAYQUEUED) == 0 && kn->kn_fop->f_event(kn, 0)) {
+               if (knoteuse2kqlock(kq, kn))
+                       knote_activate(kn, 1);
+               kqunlock(kq);
+       } else {
+               knote_put(kn);
+       }
+
+done:
+       if (fp != NULL)
+               fp_drop(p, kev->ident, fp, 0);
+       return (error);
+}
+
+
+/*
+ * knote_process - process a triggered event
+ *
+ *     Validate that it is really still a triggered event
+ *     by calling the filter routines (if necessary).  Hold
+ *     a use reference on the knote to avoid it being detached.
+ *     If it is still considered triggered, invoke the callback
+ *     routine provided and move it to the provided inprocess
+ *     queue.
+ *
+ *     caller holds a reference on the kqueue.
+ *     kqueue locked on entry and exit - but may be dropped
+ */
+static int
+knote_process(struct knote     *kn,
+             kevent_callback_t callback,
+             void              *data, 
+             struct kqtailq    *inprocessp, 
+             struct proc       *p)
+{
+       struct kqueue *kq = kn->kn_kq;
+       struct kevent64_s kev;
+       int touch;
+       int result;
+       int error;
+
+       /*
+        * Determine the kevent state we want to return.
+        *
+        * Some event states need to be revalidated before returning
+        * them, others we take the snapshot at the time the event
+        * was enqueued.
+        *
+        * Events with non-NULL f_touch operations must be touched.
+        * Triggered events must fill in kev for the callback.
+        *
+        * Convert our lock to a use-count and call the event's
+        * filter routine(s) to update.
+        */
+       if ((kn->kn_status & KN_DISABLED) != 0) {
+               result = 0;
+               touch = 0;
+       } else {
+               int revalidate;
+
+               result = 1;
+               revalidate = ((kn->kn_status & KN_STAYQUEUED) != 0 ||
+                             (kn->kn_flags & EV_ONESHOT) == 0);
+               touch = (!kn->kn_fop->f_isfd && kn->kn_fop->f_touch != NULL);
+
+               if (revalidate || touch) {
+                       if (revalidate)
+                               knote_deactivate(kn);
+                       
+                       /* call the filter/touch routines with just a ref */
+                       if (kqlock2knoteuse(kq, kn)) {
+                       
+                               /* if we have to revalidate, call the filter */
+                               if (revalidate) {
+                                       result = kn->kn_fop->f_event(kn, 0);
+                               }
+
+                               /* capture the kevent data - using touch if specified */
+                               if (result && touch) {
+                                       kn->kn_fop->f_touch(kn, &kev, EVENT_PROCESS);
+                               }
+
+                               /* convert back to a kqlock - bail if the knote went away */
+                               if (!knoteuse2kqlock(kq, kn)) {
+                                       return EJUSTRETURN;
+                               } else if (result) {
+                                       /* if revalidated as alive, make sure it's active */
+                                       if (!(kn->kn_status & KN_ACTIVE)) {
+                                               knote_activate(kn, 0);
+                                       }
+
+                                       /* capture all events that occurred during filter */
+                                       if (!touch) {
+                                               kev = kn->kn_kevent;
+                                       }
+
+                               } else if ((kn->kn_status & KN_STAYQUEUED) == 0) {
+                                       /* was already dequeued, so just bail on this one */
+                                       return EJUSTRETURN;
+                               }
+                       } else {
+                               return EJUSTRETURN;
+                       }
+               } else {
+                       kev = kn->kn_kevent;
+               }
+       }
+               
+       /* move knote onto inprocess queue */
+       assert(kn->kn_tq == &kq->kq_head);
+       TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe);
+       kn->kn_tq = inprocessp;
+       TAILQ_INSERT_TAIL(inprocessp, kn, kn_tqe);
+
+       /*
+        * Determine how to dispatch the knote for future event handling.
+        * not-fired: just return (do not callout).
+        * One-shot: deactivate it.
+        * Clear: deactivate and clear the state.
+        * Dispatch: don't clear state, just deactivate it and mark it disabled.
+        * All others: just leave where they are.
+        */
+
+       if (result == 0) {
+               return EJUSTRETURN;
+       } else if ((kn->kn_flags & EV_ONESHOT) != 0) {
+               knote_deactivate(kn);
+               if (kqlock2knotedrop(kq, kn)) {
+                       kn->kn_fop->f_detach(kn);
+                       knote_drop(kn, p);
+               }
+       } else if ((kn->kn_flags & (EV_CLEAR | EV_DISPATCH)) != 0) {
+               if ((kn->kn_flags & EV_DISPATCH) != 0) {
+                       /* deactivate and disable all dispatch knotes */
+                       knote_deactivate(kn);
+                       kn->kn_status |= KN_DISABLED;
+               } else if (!touch || kn->kn_fflags == 0) {
+                       /* only deactivate if nothing since the touch */
+                       knote_deactivate(kn);
+               }
+               if (!touch && (kn->kn_flags & EV_CLEAR) != 0) {
+                       /* manually clear non-touch knotes */
+                       kn->kn_data = 0;
+                       kn->kn_fflags = 0;
+               }
+               kqunlock(kq);
+       } else {
+               /*
+                * leave on inprocess queue.  We'll
+                * move all the remaining ones back
+                * the kq queue and wakeup any
+                * waiters when we are done.
+                */
+               kqunlock(kq);
+       }
+
+       /* callback to handle each event as we find it */
+       error = (callback)(kq, &kev, data);
+       
+       kqlock(kq);
+       return error;
+}
+
+/*
+ * Return 0 to indicate that processing should proceed,
+ * -1 if there is nothing to process.
  *
+ * Called with kqueue locked and returns the same way,
+ * but may drop lock temporarily.
+ */
+static int
+kqueue_begin_processing(struct kqueue *kq)
+{
+       for (;;) {
+               if (kq->kq_count == 0) {
+                       return -1;
+               }
+
+               /* if someone else is processing the queue, wait */
+               if (kq->kq_nprocess != 0) {
+                       wait_queue_assert_wait((wait_queue_t)kq->kq_wqs, &kq->kq_nprocess, THREAD_UNINT, 0);
+                       kq->kq_state |= KQ_PROCWAIT;
+                       kqunlock(kq);
+                       thread_block(THREAD_CONTINUE_NULL);
+                       kqlock(kq);
+               } else {
+                       kq->kq_nprocess = 1;
+                       return 0;
+               }
+       }
+}
+
+/*
+ * Called with kqueue lock held.
  */
+static void
+kqueue_end_processing(struct kqueue *kq)
+{
+       kq->kq_nprocess = 0;
+       if (kq->kq_state & KQ_PROCWAIT) {
+               kq->kq_state &= ~KQ_PROCWAIT;
+               wait_queue_wakeup_all((wait_queue_t)kq->kq_wqs, &kq->kq_nprocess, THREAD_AWAKENED);
+       }
+}
+
 /*
- *     @(#)kern_event.c       1.0 (3/31/2000)
+ * kqueue_process - process the triggered events in a kqueue
+ *
+ *     Walk the queued knotes and validate that they are
+ *     really still triggered events by calling the filter
+ *     routines (if necessary).  Hold a use reference on
+ *     the knote to avoid it being detached. For each event
+ *     that is still considered triggered, invoke the
+ *     callback routine provided.
+ *
+ *     caller holds a reference on the kqueue.
+ *     kqueue locked on entry and exit - but may be dropped
+ *     kqueue list locked (held for duration of call)
+ */
+
+static int
+kqueue_process(struct kqueue *kq,
+              kevent_callback_t callback,
+              void *data, 
+              int *countp,
+              struct proc *p)
+{
+        struct kqtailq inprocess;
+       struct knote *kn;
+       int nevents;
+       int error;
+
+        TAILQ_INIT(&inprocess);
+
+       if (kqueue_begin_processing(kq) == -1) {
+               *countp = 0;
+               /* Nothing to process */
+               return 0;
+       }
+
+       /*
+        * Clear any pre-posted status from previous runs, so we only
+        * detect events that occur during this run.
+        */
+       wait_queue_sub_clearrefs(kq->kq_wqs);
+
+       /*
+        * loop through the enqueued knotes, processing each one and
+        * revalidating those that need it. As they are processed,
+        * they get moved to the inprocess queue (so the loop can end).
+        */
+       error = 0;
+       nevents = 0;
+
+       while (error == 0 &&
+              (kn = TAILQ_FIRST(&kq->kq_head)) != NULL) {
+               error = knote_process(kn, callback, data, &inprocess, p);
+               if (error == EJUSTRETURN)
+                       error = 0;
+               else
+                       nevents++;
+       }
+
+       /*
+        * With the kqueue still locked, move any knotes
+        * remaining on the inprocess queue back to the
+        * kq's queue and wake up any waiters.
+        */
+       while ((kn = TAILQ_FIRST(&inprocess)) != NULL) {
+               assert(kn->kn_tq == &inprocess);
+               TAILQ_REMOVE(&inprocess, kn, kn_tqe);
+               kn->kn_tq = &kq->kq_head;
+               TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe);
+       }
+
+       kqueue_end_processing(kq);
+
+       *countp = nevents;
+       return error;
+}
+
+
+static void
+kqueue_scan_continue(void *data, wait_result_t wait_result)
+{
+       thread_t self = current_thread();
+       uthread_t ut = (uthread_t)get_bsdthread_info(self);
+       struct _kqueue_scan * cont_args = &ut->uu_kevent.ss_kqueue_scan;
+       struct kqueue *kq = (struct kqueue *)data;
+       int error;
+       int count;
+
+       /* convert the (previous) wait_result to a proper error */
+       switch (wait_result) {
+       case THREAD_AWAKENED:
+               kqlock(kq);
+               error = kqueue_process(kq, cont_args->call, cont_args, &count, current_proc());
+               if (error == 0 && count == 0) {
+                       wait_queue_assert_wait((wait_queue_t)kq->kq_wqs, KQ_EVENT, 
+                                              THREAD_ABORTSAFE, cont_args->deadline); 
+                       kq->kq_state |= KQ_SLEEP;
+                       kqunlock(kq);
+                       thread_block_parameter(kqueue_scan_continue, kq);
+                       /* NOTREACHED */
+               }
+               kqunlock(kq);
+               break;
+       case THREAD_TIMED_OUT:
+               error = EWOULDBLOCK; 
+               break;
+       case THREAD_INTERRUPTED:
+               error = EINTR;
+               break;
+       default:
+               panic("kevent_scan_cont() - invalid wait_result (%d)", wait_result);
+               error = 0;
+       }
+       
+       /* call the continuation with the results */
+       assert(cont_args->cont != NULL);
+       (cont_args->cont)(kq, cont_args->data, error);
+}
+
+
+/*
+ * kqueue_scan - scan and wait for events in a kqueue
+ *
+ *     Process the triggered events in a kqueue.
+ *
+ *     If there are no events triggered arrange to
+ *     wait for them. If the caller provided a
+ *     continuation routine, then kevent_scan will
+ *     also.
+ *
+ *     The callback routine must be valid.
+ *     The caller must hold a use-count reference on the kq.
+ */
+
+int
+kqueue_scan(struct kqueue *kq, 
+           kevent_callback_t callback,
+           kqueue_continue_t continuation,
+           void *data,
+           struct timeval *atvp,
+           struct proc *p)
+{
+       thread_continue_t cont = THREAD_CONTINUE_NULL;
+       uint64_t deadline;
+       int error;
+       int first;
+
+       assert(callback != NULL);
+
+       first = 1;
+       for (;;) {
+               wait_result_t wait_result;
+               int count;
+
+               /*
+                * Make a pass through the kq to find events already
+                * triggered.  
+                */
+               kqlock(kq);
+               error = kqueue_process(kq, callback, data, &count, p);
+               if (error || count)
+                       break; /* lock still held */
+
+               /* looks like we have to consider blocking */
+               if (first) {
+                       first = 0;
+                       /* convert the timeout to a deadline once */
+                       if (atvp->tv_sec || atvp->tv_usec) {
+                               uint64_t now;
+                               
+                               clock_get_uptime(&now);
+                               nanoseconds_to_absolutetime((uint64_t)atvp->tv_sec * NSEC_PER_SEC +
+                                                           atvp->tv_usec * NSEC_PER_USEC,
+                                                           &deadline);
+                               if (now >= deadline) {
+                                       /* non-blocking call */
+                                       error = EWOULDBLOCK;
+                                       break; /* lock still held */
+                               }
+                               deadline -= now;
+                               clock_absolutetime_interval_to_deadline(deadline, &deadline);
+                       } else {
+                               deadline = 0;   /* block forever */
+                       }
+
+                       if (continuation) {
+                               uthread_t ut = (uthread_t)get_bsdthread_info(current_thread());
+                               struct _kqueue_scan *cont_args = &ut->uu_kevent.ss_kqueue_scan;
+                               
+                               cont_args->call = callback;
+                               cont_args->cont = continuation;
+                               cont_args->deadline = deadline;
+                               cont_args->data = data;
+                               cont = kqueue_scan_continue;
+                       }
+               }
+
+               /* go ahead and wait */
+               wait_queue_assert_wait((wait_queue_t)kq->kq_wqs, KQ_EVENT, THREAD_ABORTSAFE, deadline);
+               kq->kq_state |= KQ_SLEEP;
+               kqunlock(kq);
+               wait_result = thread_block_parameter(cont, kq);
+               /* NOTREACHED if (continuation != NULL) */
+
+               switch (wait_result) {
+               case THREAD_AWAKENED:
+                       continue;
+               case THREAD_TIMED_OUT:
+                       return EWOULDBLOCK; 
+               case THREAD_INTERRUPTED:
+                       return EINTR;
+               default:
+                       panic("kevent_scan - bad wait_result (%d)",
+                             wait_result);
+                       error = 0;
+               }
+       }
+       kqunlock(kq);
+       return error;
+}
+
+
+/*
+ * XXX
+ * This could be expanded to call kqueue_scan, if desired.
+ */
+/*ARGSUSED*/
+static int
+kqueue_read(__unused struct fileproc *fp, 
+                       __unused struct uio *uio, 
+                       __unused int flags, 
+                       __unused vfs_context_t ctx)
+{
+       return (ENXIO);
+}
+
+/*ARGSUSED*/
+static int
+kqueue_write(__unused struct fileproc *fp, 
+                        __unused struct uio *uio, 
+                        __unused int flags, 
+                        __unused vfs_context_t ctx)
+{
+       return (ENXIO);
+}
+
+/*ARGSUSED*/
+static int
+kqueue_ioctl(__unused struct fileproc *fp, 
+                        __unused u_long com, 
+                        __unused caddr_t data, 
+                        __unused vfs_context_t ctx)
+{
+       return (ENOTTY);
+}
+
+/*ARGSUSED*/
+static int
+kqueue_select(struct fileproc *fp, int which, void *wql, __unused vfs_context_t ctx)
+{
+       struct kqueue *kq = (struct kqueue *)fp->f_data;
+       struct knote *kn;
+       struct kqtailq inprocessq;
+       int retnum = 0;
+       
+       if (which != FREAD)
+               return 0;
+
+       TAILQ_INIT(&inprocessq);
+
+       kqlock(kq);
+       /* 
+        * If this is the first pass, link the wait queue associated with the
+        * the kqueue onto the wait queue set for the select().  Normally we
+        * use selrecord() for this, but it uses the wait queue within the
+        * selinfo structure and we need to use the main one for the kqueue to
+        * catch events from KN_STAYQUEUED sources. So we do the linkage manually.
+        * (The select() call will unlink them when it ends).
+        */
+       if (wql != NULL) {
+               thread_t        cur_act = current_thread();
+               struct uthread * ut = get_bsdthread_info(cur_act);
+
+               kq->kq_state |= KQ_SEL;
+               wait_queue_link_noalloc((wait_queue_t)kq->kq_wqs, ut->uu_wqset,
+                                       (wait_queue_link_t)wql);
+       }
+
+       if (kqueue_begin_processing(kq) == -1) {
+               kqunlock(kq);
+               return 0;
+       }
+
+       if (kq->kq_count != 0) {
+               /*
+                * there is something queued - but it might be a
+                * KN_STAYQUEUED knote, which may or may not have
+                * any events pending.  So, we have to walk the
+                * list of knotes to see, and peek at the stay-
+                * queued ones to be really sure.
+                */
+               while ((kn = (struct knote*)TAILQ_FIRST(&kq->kq_head)) != NULL) {
+                       if ((kn->kn_status & KN_STAYQUEUED) == 0) {
+                               retnum = 1;
+                               goto out;
+                       }
+
+                       TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe);
+                       TAILQ_INSERT_TAIL(&inprocessq, kn, kn_tqe);
+
+                       if (kqlock2knoteuse(kq, kn)) {
+                               unsigned peek;
+
+                               peek = kn->kn_fop->f_peek(kn);
+                               if (knoteuse2kqlock(kq, kn)) {
+                                       if (peek > 0) {
+                                               retnum = 1;
+                                               goto out;
+                                       }
+                               } else {
+                                       retnum = 0;
+                               }
+                       } 
+               }
+       }
+
+out:
+       /* Return knotes to active queue */
+       while ((kn = TAILQ_FIRST(&inprocessq)) != NULL) {
+               TAILQ_REMOVE(&inprocessq, kn, kn_tqe);
+               kn->kn_tq = &kq->kq_head;
+               TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe);
+       }
+
+       kqueue_end_processing(kq);
+       kqunlock(kq);
+       return retnum;
+}
+
+/*
+ * kqueue_close -
+ */
+/*ARGSUSED*/
+static int
+kqueue_close(struct fileglob *fg, __unused vfs_context_t ctx)
+{
+       struct kqueue *kq = (struct kqueue *)fg->fg_data;
+
+       kqueue_dealloc(kq);
+       fg->fg_data = NULL;
+       return (0);
+}
+
+/*ARGSUSED*/
+/*
+ * The callers has taken a use-count reference on this kqueue and will donate it
+ * to the kqueue we are being added to.  This keeps the kqueue from closing until
+ * that relationship is torn down.
+ */
+static int
+kqueue_kqfilter(__unused struct fileproc *fp, struct knote *kn, __unused vfs_context_t ctx)
+{
+       struct kqueue *kq = (struct kqueue *)kn->kn_fp->f_data;
+       struct kqueue *parentkq = kn->kn_kq;
+
+       if (parentkq == kq ||
+           kn->kn_filter != EVFILT_READ)
+               return (1);
+
+       /*
+        * We have to avoid creating a cycle when nesting kqueues
+        * inside another.  Rather than trying to walk the whole
+        * potential DAG of nested kqueues, we just use a simple
+        * ceiling protocol.  When a kqueue is inserted into another,
+        * we check that the (future) parent is not already nested
+        * into another kqueue at a lower level than the potenial
+        * child (because it could indicate a cycle).  If that test
+        * passes, we just mark the nesting levels accordingly.
+        */
+
+       kqlock(parentkq);
+       if (parentkq->kq_level > 0 && 
+           parentkq->kq_level < kq->kq_level)
+       {
+               kqunlock(parentkq);
+               return (1);
+       } else {
+               /* set parent level appropriately */
+               if (parentkq->kq_level == 0)
+                       parentkq->kq_level = 2;
+               if (parentkq->kq_level < kq->kq_level + 1)
+                       parentkq->kq_level = kq->kq_level + 1;
+               kqunlock(parentkq);
+
+               kn->kn_fop = &kqread_filtops;
+               kqlock(kq);
+               KNOTE_ATTACH(&kq->kq_sel.si_note, kn);
+               /* indicate nesting in child, if needed */
+               if (kq->kq_level == 0)
+                       kq->kq_level = 1;
+               kqunlock(kq);
+               return (0);
+       }
+}
+
+/*
+ * kqueue_drain - called when kq is closed
+ */
+/*ARGSUSED*/
+static int
+kqueue_drain(struct fileproc *fp, __unused vfs_context_t ctx)
+{
+       struct kqueue *kq = (struct kqueue *)fp->f_fglob->fg_data;
+       kqlock(kq);
+       kqueue_wakeup(kq, 1);
+       kqunlock(kq);
+       return 0;
+}
+
+/*ARGSUSED*/
+int
+kqueue_stat(struct fileproc *fp, void *ub, int isstat64,  __unused vfs_context_t ctx)
+{
+
+       struct kqueue *kq = (struct kqueue *)fp->f_data;
+       if (isstat64 != 0) {
+               struct stat64 *sb64 = (struct stat64 *)ub;
+
+               bzero((void *)sb64, sizeof(*sb64));
+               sb64->st_size = kq->kq_count;
+               if (kq->kq_state & KQ_KEV64)
+                       sb64->st_blksize = sizeof(struct kevent64_s);
+               else
+                       sb64->st_blksize = sizeof(struct kevent);
+               sb64->st_mode = S_IFIFO;
+       } else {
+               struct stat *sb = (struct stat *)ub;
+
+               bzero((void *)sb, sizeof(*sb));
+               sb->st_size = kq->kq_count;
+               if (kq->kq_state & KQ_KEV64)
+                       sb->st_blksize = sizeof(struct kevent64_s);
+               else
+                       sb->st_blksize = sizeof(struct kevent);
+               sb->st_mode = S_IFIFO;
+       }
+
+       return (0);
+}
+
+/*
+ * Called with the kqueue locked
+ */
+static void
+kqueue_wakeup(struct kqueue *kq, int closed)
+{
+       if ((kq->kq_state & (KQ_SLEEP | KQ_SEL)) != 0 || kq->kq_nprocess > 0) {
+               kq->kq_state &= ~(KQ_SLEEP | KQ_SEL);
+               wait_queue_wakeup_all((wait_queue_t)kq->kq_wqs, KQ_EVENT, 
+                                     (closed) ? THREAD_INTERRUPTED : THREAD_AWAKENED);
+       }
+}
+
+void
+klist_init(struct klist *list)
+{
+       SLIST_INIT(list);
+}
+
+
+/*
+ * Query/Post each knote in the object's list
+ *
+ *     The object lock protects the list. It is assumed
+ *     that the filter/event routine for the object can
+ *     determine that the object is already locked (via
+ *     the hint) and not deadlock itself.
+ *
+ *     The object lock should also hold off pending
+ *     detach/drop operations.  But we'll prevent it here
+ *     too - just in case.
+ */
+void
+knote(struct klist *list, long hint)
+{
+       struct knote *kn;
+
+       SLIST_FOREACH(kn, list, kn_selnext) {
+               struct kqueue *kq = kn->kn_kq;
+
+               kqlock(kq);
+               if (kqlock2knoteuse(kq, kn)) {
+                       int result;
+
+                       /* call the event with only a use count */
+                       result = kn->kn_fop->f_event(kn, hint);
+
+                       /* if its not going away and triggered */
+                       if (knoteuse2kqlock(kq, kn) && result)
+                               knote_activate(kn, 1);
+                       /* lock held again */
+               }
+               kqunlock(kq);
+       }
+}
+
+/*
+ * attach a knote to the specified list.  Return true if this is the first entry.
+ * The list is protected by whatever lock the object it is associated with uses.
+ */
+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.
+ * The list is protected by whatever lock the object it is associated with uses.
+ */
+int
+knote_detach(struct klist *list, struct knote *kn)
+{
+       SLIST_REMOVE(list, kn, knote, kn_selnext);
+       return SLIST_EMPTY(list);
+}
+
+/*
+ * For a given knote, link a provided wait queue directly with the kqueue.
+ * Wakeups will happen via recursive wait queue support.  But nothing will move 
+ * the knote to the active list at wakeup (nothing calls knote()).  Instead,
+ * we permanently enqueue them here.
+ *
+ * kqueue and knote references are held by caller.
+ *
+ * caller provides the wait queue link structure.
+ */
+int
+knote_link_wait_queue(struct knote *kn, struct wait_queue *wq, wait_queue_link_t wql)
+{
+       struct kqueue *kq = kn->kn_kq;
+       kern_return_t kr;
+
+       kr = wait_queue_link_noalloc(wq, kq->kq_wqs, wql);
+       if (kr == KERN_SUCCESS) {
+               knote_markstayqueued(kn);
+               return 0;
+       } else {
+               return EINVAL;
+       }
+}
+
+/*
+ * Unlink the provided wait queue from the kqueue associated with a knote.
+ * Also remove it from the magic list of directly attached knotes.
+ *
+ * Note that the unlink may have already happened from the other side, so
+ * ignore any failures to unlink and just remove it from the kqueue list.
+ *
+ * On success, caller is responsible for the link structure
+ */
+int
+knote_unlink_wait_queue(struct knote *kn, struct wait_queue *wq, wait_queue_link_t *wqlp)
+{
+       struct kqueue *kq = kn->kn_kq;
+       kern_return_t kr;
+
+       kr = wait_queue_unlink_nofree(wq, kq->kq_wqs, wqlp);
+       kqlock(kq);
+       kn->kn_status &= ~KN_STAYQUEUED;
+       knote_dequeue(kn);
+       kqunlock(kq);
+       return (kr != KERN_SUCCESS) ? EINVAL : 0;
+}
+
+/*
+ * remove all knotes referencing a specified fd
+ *
+ * Essentially an inlined knote_remove & knote_drop
+ * when we know for sure that the thing is a file
+ * 
+ * Entered with the proc_fd lock already held.
+ * It returns the same way, but may drop it temporarily.
+ */
+void
+knote_fdclose(struct proc *p, int fd)
+{
+       struct filedesc *fdp = p->p_fd;
+       struct klist *list;
+       struct knote *kn;
+
+       list = &fdp->fd_knlist[fd];
+       while ((kn = SLIST_FIRST(list)) != NULL) {
+               struct kqueue *kq = kn->kn_kq;
+
+               if (kq->kq_p != p)
+                       panic("knote_fdclose: proc mismatch (kq->kq_p=%p != p=%p)", kq->kq_p, p);
+
+               kqlock(kq);
+               proc_fdunlock(p);
+
+               /*
+                * Convert the lock to a drop ref.
+                * If we get it, go ahead and drop it.
+                * Otherwise, we waited for it to
+                * be dropped by the other guy, so
+                * it is safe to move on in the list.
+                */
+               if (kqlock2knotedrop(kq, kn)) {
+                       kn->kn_fop->f_detach(kn);
+                       knote_drop(kn, p);
+               }
+                       
+               proc_fdlock(p);
+
+               /* the fd tables may have changed - start over */
+               list = &fdp->fd_knlist[fd];
+       }
+}
+
+/* proc_fdlock held on entry (and exit) */
+static int
+knote_fdpattach(struct knote *kn, struct filedesc *fdp, struct proc *p)
+{
+       struct klist *list = NULL;
+
+       if (! kn->kn_fop->f_isfd) {
+               if (fdp->fd_knhashmask == 0)
+                       fdp->fd_knhash = hashinit(CONFIG_KN_HASHSIZE, M_KQUEUE,
+                           &fdp->fd_knhashmask);
+               list = &fdp->fd_knhash[KN_HASH(kn->kn_id, fdp->fd_knhashmask)];
+       } else {
+               if ((u_int)fdp->fd_knlistsize <= kn->kn_id) {
+                       u_int size = 0;
+
+                       if (kn->kn_id >= (uint64_t)p->p_rlimit[RLIMIT_NOFILE].rlim_cur 
+                           || kn->kn_id >= (uint64_t)maxfiles)
+                               return (EINVAL);
+               
+                       /* have to grow the fd_knlist */
+                       size = fdp->fd_knlistsize;
+                       while (size <= kn->kn_id)
+                               size += KQEXTENT;
+
+                       if (size >= (UINT_MAX/sizeof(struct klist *)))
+                               return (EINVAL);
+
+                       MALLOC(list, struct klist *,
+                              size * sizeof(struct klist *), M_KQUEUE, M_WAITOK);
+                       if (list == NULL)
+                               return (ENOMEM);
+                       
+                       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 *));
+                       FREE(fdp->fd_knlist, M_KQUEUE);
+                       fdp->fd_knlist = list;
+                       fdp->fd_knlistsize = size;
+               }
+               list = &fdp->fd_knlist[kn->kn_id];
+       }
+       SLIST_INSERT_HEAD(list, kn, kn_link);
+       return (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, __unused struct proc *ctxp)
+{
+       struct kqueue *kq = kn->kn_kq;
+       struct proc *p = kq->kq_p;
+        struct filedesc *fdp = p->p_fd;
+       struct klist *list;
+       int needswakeup;
+
+       proc_fdlock(p);
+       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);
+       kqlock(kq);
+       knote_dequeue(kn);
+       needswakeup = (kn->kn_status & KN_USEWAIT);
+       kqunlock(kq);
+       proc_fdunlock(p);
+
+       if (needswakeup)
+               wait_queue_wakeup_all((wait_queue_t)kq->kq_wqs, &kn->kn_status, THREAD_AWAKENED);
+
+       if (kn->kn_fop->f_isfd)
+               fp_drop(p, kn->kn_id, kn->kn_fp, 0);
+
+       knote_free(kn);
+}
+
+/* called with kqueue lock held */
+static void
+knote_activate(struct knote *kn, int propagate)
+{
+       struct kqueue *kq = kn->kn_kq;
+
+       kn->kn_status |= KN_ACTIVE;
+       knote_enqueue(kn);
+       kqueue_wakeup(kq, 0);
+
+       /* this is a real event: wake up the parent kq, too */
+       if (propagate)
+               KNOTE(&kq->kq_sel.si_note, 0);
+}
+
+/* called with kqueue lock held */
+static void
+knote_deactivate(struct knote *kn)
+{      
+       kn->kn_status &= ~KN_ACTIVE;
+       knote_dequeue(kn);
+}
+
+/* called with kqueue lock held */
+static void
+knote_enqueue(struct knote *kn)
+{
+       if ((kn->kn_status & (KN_QUEUED | KN_STAYQUEUED)) == KN_STAYQUEUED ||
+           (kn->kn_status & (KN_QUEUED | KN_STAYQUEUED | KN_DISABLED)) == 0) {
+               struct kqtailq *tq = kn->kn_tq;
+               struct kqueue *kq = kn->kn_kq;
+
+               TAILQ_INSERT_TAIL(tq, kn, kn_tqe); 
+               kn->kn_status |= KN_QUEUED;
+               kq->kq_count++;
+       }
+}
+
+/* called with kqueue lock held */
+static void
+knote_dequeue(struct knote *kn)
+{
+       struct kqueue *kq = kn->kn_kq;
+
+       if ((kn->kn_status & (KN_QUEUED | KN_STAYQUEUED)) == KN_QUEUED) {
+               struct kqtailq *tq = kn->kn_tq;
 
+               TAILQ_REMOVE(tq, kn, kn_tqe); 
+               kn->kn_tq = &kq->kq_head;
+               kn->kn_status &= ~KN_QUEUED;
+               kq->kq_count--;
+       }
+}
+
+void
+knote_init(void)
+{
+       knote_zone = zinit(sizeof(struct knote), 8192*sizeof(struct knote), 8192, "knote zone");
+
+       /* allocate kq lock group attribute and group */
+       kq_lck_grp_attr= lck_grp_attr_alloc_init();
+
+       kq_lck_grp = lck_grp_alloc_init("kqueue",  kq_lck_grp_attr);
+
+       /* Allocate kq lock attribute */
+       kq_lck_attr = lck_attr_alloc_init();
+
+       /* Initialize the timer filter lock */
+       lck_mtx_init(&_filt_timerlock, kq_lck_grp, kq_lck_attr);
+       
+#if VM_PRESSURE_EVENTS
+       /* Initialize the vm pressure list lock */
+       vm_pressure_init(kq_lck_grp, kq_lck_attr);
+#endif
+}
+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);
+}
+
+#if SOCKETS
 #include <sys/param.h>
 #include <sys/socket.h>
 #include <sys/protosw.h>
 #include <sys/mbuf.h>
 #include <sys/kern_event.h>
 #include <sys/malloc.h>
+#include <sys/sys_domain.h>
+#include <sys/syslog.h>
 
 
-extern struct domain systemdomain;
-
+static int kev_attach(struct socket *so, int proto, struct proc *p);
+static int kev_detach(struct socket *so);
+static int kev_control(struct socket *so, u_long cmd, caddr_t data, struct ifnet *ifp, struct proc *p);
 
-
-int    raw_usrreq();
-struct pr_usrreqs event_usrreqs;
+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, pru_sopoll_notsupp
+};
 
 struct protosw eventsw[] = {
      {
-         SOCK_RAW,             &systemdomain,  SYSPROTO_EVENT,         PR_ATOMIC,
-         0,            0,              0,              0,
-         0,
-         0,            0,              0,              0,
-         0,            &event_usrreqs
+         .pr_type = SOCK_RAW,
+         .pr_domain = &systemdomain,
+         .pr_protocol = SYSPROTO_EVENT,
+         .pr_flags = PR_ATOMIC,
+         .pr_usrreqs = &event_usrreqs,
      }
 };
 
 static
 struct kern_event_head kern_event_head;
 
-static u_long static_event_id = 0;
+static u_int32_t static_event_id = 0;
+struct domain *sysdom = &systemdomain;
+static lck_mtx_t *sys_mtx;
+
+/*
+ * 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) {
+           log(LOG_WARNING, "Can't install kernel events protocol (%d)\n", retval);
+            return(retval);
+       }
+   
+    /*
+     * Use the domain mutex for all system event sockets
+     */ 
+    sys_mtx = sysdom->dom_mtx;
+       
+    return(KERN_SUCCESS);
+}
 
-int kev_attach(struct socket *so, int proto, struct proc *p)
+static int
+kev_attach(struct socket *so, __unused int proto, __unused struct proc *p)
 {
      int error;
      struct kern_event_pcb  *ev_pcb;
 
-     ev_pcb = _MALLOC(sizeof(struct kern_event_pcb), M_PCB, M_WAITOK);
+     error = soreserve(so, KEV_SNDSPACE, KEV_RECVSPACE);
+     if (error)
+          return error;
+
+     MALLOC(ev_pcb, struct kern_event_pcb *, sizeof(struct kern_event_pcb), M_PCB, M_WAITOK);
      if (ev_pcb == 0)
          return ENOBUFS;
 
@@ -68,26 +2789,63 @@ int kev_attach(struct socket *so, int proto, struct proc *p)
      ev_pcb->vendor_code_filter = 0xffffffff;
 
      so->so_pcb = (caddr_t) ev_pcb;
+     lck_mtx_lock(sys_mtx);
      LIST_INSERT_HEAD(&kern_event_head, ev_pcb, ev_link);
-     error = soreserve(so, KEV_SNDSPACE, KEV_RECVSPACE);
-     if (error)
-         return error;
+     lck_mtx_unlock(sys_mtx);
 
      return 0;
 }
 
 
-int kev_detach(struct socket *so)
+static int
+kev_detach(struct socket *so)
 {
      struct kern_event_pcb *ev_pcb = (struct kern_event_pcb *) so->so_pcb;
 
-     LIST_REMOVE(ev_pcb, ev_link);
-     if (ev_pcb)
-         FREE(ev_pcb, M_PCB);
+     if (ev_pcb != 0) {
+               LIST_REMOVE(ev_pcb, ev_link);
+               FREE(ev_pcb, M_PCB);
+               so->so_pcb = 0;
+               so->so_flags |= SOF_PCBCLEARING;
+     }
 
      return 0;
 }
 
+/*
+ * For now, kev_vendor_code and mbuf_tags use the same
+ * mechanism.
+ */
+
+errno_t kev_vendor_code_find(
+       const char      *string,
+       u_int32_t       *out_vendor_code)
+{
+       if (strlen(string) >= KEV_VENDOR_CODE_MAX_STR_LEN) {
+               return EINVAL;
+       }
+       return net_str_id_find_internal(string, out_vendor_code, NSI_VENDOR_CODE, 1);
+}
+
+errno_t  kev_msg_post(struct kev_msg *event_msg)
+{
+       mbuf_tag_id_t   min_vendor, max_vendor;
+       
+       net_str_id_first_last(&min_vendor, &max_vendor, NSI_VENDOR_CODE);
+       
+       if (event_msg == NULL)
+               return EINVAL;
+       
+       /* Limit third parties to posting events for registered vendor codes only */
+       if (event_msg->vendor_code < min_vendor ||
+               event_msg->vendor_code > max_vendor)
+       {
+               return EINVAL;
+       }
+       
+       return kev_post_msg(event_msg);
+}
+       
 
 int  kev_post_msg(struct kev_msg *event_msg)
 {
@@ -95,9 +2853,21 @@ int  kev_post_msg(struct kev_msg *event_msg)
      struct kern_event_pcb  *ev_pcb;
      struct kern_event_msg  *ev;
      char              *tmp;
-     int               total_size;
+     u_int32_t     total_size;
      int               i;
 
+       /* Verify the message is small enough to fit in one mbuf w/o cluster */
+       total_size = KEV_MSG_HEADER_SIZE;
+       
+       for (i = 0; i < 5; i++) {
+               if (event_msg->dv[i].data_length == 0)
+                       break;
+               total_size += event_msg->dv[i].data_length;
+       }
+       
+       if (total_size > MLEN) {
+               return EMSGSIZE;
+       }
 
      m = m_get(M_DONTWAIT, MT_DATA);
      if (m == 0)
@@ -117,7 +2887,6 @@ int  kev_post_msg(struct kev_msg *event_msg)
          tmp += event_msg->dv[i].data_length;
      }
 
-
      ev->id = ++static_event_id;
      ev->total_size   = total_size;
      ev->vendor_code  = event_msg->vendor_code;
@@ -126,7 +2895,7 @@ int  kev_post_msg(struct kev_msg *event_msg)
      ev->event_code   = event_msg->event_code;
 
      m->m_len = total_size;
-     ev_pcb = LIST_FIRST(&kern_event_head);
+     lck_mtx_lock(sys_mtx);
      for (ev_pcb = LIST_FIRST(&kern_event_head); 
          ev_pcb; 
          ev_pcb = LIST_NEXT(ev_pcb, ev_link)) {
@@ -148,67 +2917,100 @@ int  kev_post_msg(struct kev_msg *event_msg)
          m2 = m_copym(m, 0, m->m_len, M_NOWAIT);
          if (m2 == 0) {
               m_free(m);
+                  lck_mtx_unlock(sys_mtx);
               return ENOBUFS;
          }
-
-         sbappendrecord(&ev_pcb->ev_socket->so_rcv, m2);
-         sorwakeup(ev_pcb->ev_socket);
+         /* the socket is already locked because we hold the sys_mtx here */
+         if (sbappendrecord(&ev_pcb->ev_socket->so_rcv, m2))
+                 sorwakeup(ev_pcb->ev_socket);
      }
 
-
      m_free(m);
+     lck_mtx_unlock(sys_mtx);
      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;
+static int
+kev_control(struct socket *so, 
+                       u_long cmd, 
+                       caddr_t data, 
+                       __unused struct ifnet *ifp, 
+                       __unused 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;
-
+       struct kev_request *kev_req = (struct kev_request *) data;
+       struct kern_event_pcb  *ev_pcb;
+       struct kev_vendor_code *kev_vendor;
+       u_int32_t  *id_value = (u_int32_t *) 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;
+               
+               case SIOCGKEVVENDOR:
+                       kev_vendor = (struct kev_vendor_code*)data;
+                       
+                       /* Make sure string is NULL terminated */
+                       kev_vendor->vendor_string[KEV_VENDOR_CODE_MAX_STR_LEN-1] = 0;
+               
+                       return net_str_id_find_internal(kev_vendor->vendor_string, 
+                                       &kev_vendor->vendor_code, NSI_VENDOR_CODE, 0);
+               
+               default:
+                       return ENOTSUP;
+       }
+       
+       return 0;
+}
 
-     switch (cmd) {
+#endif /* SOCKETS */
 
-     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;
+int
+fill_kqueueinfo(struct kqueue *kq, struct kqueue_info * kinfo)
+{
+       struct vinfo_stat * st;
 
-     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;
+       /* No need for the funnel as fd is kept alive */
+       
+       st = &kinfo->kq_stat;
 
-     default:
-         return EOPNOTSUPP;
-     }
+       st->vst_size = kq->kq_count;
+       if (kq->kq_state & KQ_KEV64)
+               st->vst_blksize = sizeof(struct kevent64_s);
+       else
+               st->vst_blksize = sizeof(struct kevent);
+       st->vst_mode = S_IFIFO;
+       if (kq->kq_state & KQ_SEL)
+               kinfo->kq_state |=  PROC_KQUEUE_SELECT;
+       if (kq->kq_state & KQ_SLEEP)
+               kinfo->kq_state |= PROC_KQUEUE_SLEEP;
 
-     return 0;
+       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
-};
-
-
-
+void
+knote_markstayqueued(struct knote *kn)
+{
+       kqlock(kn->kn_kq);
+       kn->kn_status |= KN_STAYQUEUED;
+       knote_enqueue(kn);
+       kqunlock(kn->kn_kq);
+}