]> git.saurik.com Git - apple/xnu.git/blobdiff - bsd/kern/kern_event.c
xnu-2782.40.9.tar.gz
[apple/xnu.git] / bsd / kern / kern_event.c
index ae5b11c708d8fe36ea8de4b573c85dcac9846097..708aef4747ad4ddd1bbeef79d7c7fdf43cedaa9f 100644 (file)
@@ -1,8 +1,8 @@
 /*
- * Copyright (c) 2000-2005 Apple Computer, Inc. All rights reserved.
+ * Copyright (c) 2000-2014 Apple Inc. All rights reserved.
  *
  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
- * 
+ *
  * 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
  * 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.
- * 
+ *
  * 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,
@@ -22,7 +22,7 @@
  * 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_OSREFERENCE_LICENSE_HEADER_END@
  *
  */
@@ -62,7 +62,7 @@
 #include <sys/kernel.h>
 #include <sys/proc_internal.h>
 #include <sys/kauth.h>
-#include <sys/malloc.h> 
+#include <sys/malloc.h>
 #include <sys/unistd.h>
 #include <sys/file_internal.h>
 #include <sys/fcntl.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 <sys/codesign.h>
 
-#include <kern/lock.h>
+#include <kern/locks.h>
 #include <kern/clock.h>
 #include <kern/thread_call.h>
 #include <kern/sched_prim.h>
+#include <kern/wait_queue.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
 
-extern void unix_syscall_return(int);
+#if CONFIG_MEMORYSTATUS
+#include <sys/kern_memorystatus.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);
-static int     kqueue_read(struct fileproc *fp, struct uio *uio,
-                   kauth_cred_t cred, int flags, struct proc *p);
-static int     kqueue_write(struct fileproc *fp, struct uio *uio,
-                   kauth_cred_t cred, int flags, struct proc *p);
-static int     kqueue_ioctl(struct fileproc *fp, u_long com, caddr_t data,
-                   struct proc *p);
-static int     kqueue_select(struct fileproc *fp, int which, void *wql, 
-                   struct proc *p);
-static int     kqueue_close(struct fileglob *fp, struct proc *p);
-static int     kqueue_kqfilter(struct fileproc *fp, struct knote *kn, struct proc *p);
-extern int     kqueue_stat(struct fileproc *fp, struct stat *st, struct proc *p);
-
-static struct fileops kqueueops = {
-       kqueue_read,
-       kqueue_write,
-       kqueue_ioctl,
-       kqueue_select,
-       kqueue_close,
-       kqueue_kqfilter,
-       0
+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);
+
+static const struct fileops kqueueops = {
+       .fo_type = DTYPE_KQUEUE,
+       .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_copyin(user_addr_t *addrp, struct kevent *kevp, struct proc *p);
-static int kevent_copyout(struct kevent *kevp, user_addr_t *addrp, struct proc *p);
-
-static int     kevent_callback(struct kqueue *kq, struct kevent *kevp, void *data);
-static void    kevent_continue(struct kqueue *kq, void *data, int error);
-static void    kevent_scan_continue(void *contp, wait_result_t wait_result);
-static int     kevent_process(struct kqueue *kq, kevent_callback_t callback,
-                              void *data, int *countp, 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);
-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);
-extern void    knote_init(void);
-
-static int     filt_fileattach(struct knote *kn);
-static struct filterops file_filtops =
-       { 1, filt_fileattach, NULL, NULL };
-
-static void    filt_kqdetach(struct knote *kn);
-static int     filt_kqueue(struct knote *kn, long hint);
-static struct filterops kqread_filtops =
-       { 1, NULL, filt_kqdetach, filt_kqueue };
+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,
+};
 
-/*
- * placeholder for not-yet-implemented filters
- */ 
-static int     filt_badattach(struct knote *kn);
-static struct filterops bad_filtops =
-       { 0, filt_badattach, 0 , 0 };
+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,
+};
 
-static int     filt_procattach(struct knote *kn);
-static void    filt_procdetach(struct knote *kn);
-static int     filt_proc(struct knote *kn, long hint);
+#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 */
 
-static struct filterops proc_filtops =
-       { 0, filt_procattach, filt_procdetach, filt_proc };
+#if CONFIG_MEMORYSTATUS
+extern struct filterops memorystatus_filtops;
+#endif /* CONFIG_MEMORYSTATUS */
 
 extern struct filterops fs_filtops;
 
 extern struct filterops sig_filtops;
 
-
 /* Timer filter */
-static int     filt_timercompute(struct knote *kn, uint64_t *abs_time);
-static void    filt_timerexpire(void *knx, void *param1);
-static int     filt_timerattach(struct knote *kn);
-static void    filt_timerdetach(struct knote *kn);
-static int     filt_timer(struct knote *kn, long hint);
+static int filt_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,
+};
 
-static struct filterops timer_filtops =
-       { 0, filt_timerattach, filt_timerdetach, filt_timer };
+/* 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);
 
-/* to avoid arming timers that fire quicker than we can handle */
-static uint64_t        filt_timerfloor = 0; 
+#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 void filt_timerlock(void);
+static void filt_timerunlock(void);
 
-/*
- * Sentinel marker for a thread scanning through the list of
- * active knotes.
- */
-static struct filterops threadmarker_filtops =
-       { 0, filt_badattach, 0, 0 };
+static zone_t knote_zone;
 
-static zone_t  knote_zone;
-
-#define        KN_HASHSIZE             64              /* XXX should be tunable */
-#define KN_HASH(val, mask)     (((val) ^ (val >> 8)) & (mask))
+#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.
+ * Table for all system-defined filters.
  */
 static struct filterops *sysfilt_ops[] = {
        &file_filtops,                  /* EVFILT_READ */
@@ -219,8 +284,21 @@ static struct filterops *sysfilt_ops[] = {
        &proc_filtops,                  /* EVFILT_PROC */
        &sig_filtops,                   /* EVFILT_SIGNAL */
        &timer_filtops,                 /* EVFILT_TIMER */
-       &bad_filtops,                   /* EVFILT_MACHPORT */
-       &fs_filtops                     /* EVFILT_FS */
+       &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 */
+#if CONFIG_MEMORYSTATUS
+       &memorystatus_filtops,  /* EVFILT_MEMORYSTATUS */
+#else
+       &bad_filtops,                   /* EVFILT_MEMORYSTATUS */
+#endif
 };
 
 /*
@@ -246,13 +324,12 @@ 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
  */
@@ -260,36 +337,39 @@ static int
 kqlock2knoteuse(struct kqueue *kq, struct knote *kn)
 {
        if (kn->kn_status & KN_DROPPING)
-               return 0;
+               return (0);
        kn->kn_inuse++;
        kqunlock(kq);
-       return 1;
- }
+       return (1);
+}
 
-/* 
- * Convert a kq lock to a knote use referece.
+/*
+ * 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 (!kqlock2knoteuse(kq, kn)) {
-               kn->kn_status |= KN_DROPWAIT;
-               assert_wait(&kn->kn_status, THREAD_UNINT);
+       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;
+               return (0);
        }
-       return 1;
- }
+       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
@@ -303,23 +383,28 @@ static int
 knoteuse2kqlock(struct kqueue *kq, struct knote *kn)
 {
        kqlock(kq);
-       if ((--kn->kn_inuse == 0) &&
-           (kn->kn_status & KN_USEWAIT)) {
-               kn->kn_status &= ~KN_USEWAIT;
-               thread_wakeup(&kn->kn_inuse);
+       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.
+/*
+ * Convert a kq lock to a knote drop reference.
  *
  *     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
@@ -328,27 +413,26 @@ knoteuse2kqlock(struct kqueue *kq, struct knote *kn)
 static int
 kqlock2knotedrop(struct kqueue *kq, struct knote *kn)
 {
+       int oktodrop;
 
-       if ((kn->kn_status & KN_DROPPING) == 0) {
-               kn->kn_status |= KN_DROPPING;
-               if (kn->kn_inuse > 0) {
-                       kn->kn_status |= KN_USEWAIT;
-                       assert_wait(&kn->kn_inuse, THREAD_UNINT);
-                       kqunlock(kq);
-                       thread_block(THREAD_CONTINUE_NULL);
-               } else
+       oktodrop = ((kn->kn_status & (KN_DROPPING | KN_ATTACHING)) == 0);
+       kn->kn_status &= ~KN_STAYQUEUED;
+       kn->kn_status |= KN_DROPPING;
+       if (oktodrop) {
+               if (kn->kn_inuse == 0) {
                        kqunlock(kq);
-               return 1;
-       } else {
-               kn->kn_status |= KN_DROPWAIT;
-               assert_wait(&kn->kn_status, THREAD_UNINT);
-               kqunlock(kq);
-               thread_block(THREAD_CONTINUE_NULL);
-               return 0;
+                       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
@@ -357,30 +441,28 @@ knote_put(struct knote *kn)
        struct kqueue *kq = kn->kn_kq;
 
        kqlock(kq);
-       if ((--kn->kn_inuse == 0) && 
-           (kn->kn_status & KN_USEWAIT)) {
-               kn->kn_status &= ~KN_USEWAIT;
-               thread_wakeup(&kn->kn_inuse);
+       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, current_proc()));
+       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
+#define        f_flag f_fglob->fg_flag
+#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)
@@ -406,129 +488,242 @@ static int
 filt_procattach(struct knote *kn)
 {
        struct proc *p;
-       int funnel_state;
-       
-       funnel_state = thread_funnel_set(kernel_flock, TRUE);
 
-       p = pfind(kn->kn_id);
+       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) {
-               thread_funnel_set(kernel_flock, funnel_state);
                return (ESRCH);
        }
 
-       kn->kn_flags |= EV_CLEAR;               /* automatically set */
+       const int NoteExitStatusBits = NOTE_EXIT | NOTE_EXITSTATUS;
 
-       /*
-        * internal flag indicating registration done by kernel
-        */
-       if (kn->kn_flags & EV_FLAG1) {
-               kn->kn_data = (int)kn->kn_sdata;        /* ppid */
-               kn->kn_fflags = NOTE_CHILD;
-               kn->kn_flags &= ~EV_FLAG1;
-       }
+       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 */
 
-       /* XXX lock the proc here while adding to the list? */
        KNOTE_ATTACH(&p->p_klist, kn);
 
-       thread_funnel_set(kernel_flock, funnel_state);
+       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.  So when the process
- * exits, the knote is marked as DETACHED and also flagged as ONESHOT so
- * it will be deleted when read out.  However, as part of the knote deletion,
- * this routine is called, so a check is needed to avoid actually performing
- * a detach, because the original process does not exist any more.
+ * 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;
-       int funnel_state;
 
-       funnel_state = thread_funnel_set(kernel_flock, TRUE);
-       p = pfind(kn->kn_id);
+       proc_klist_lock();
 
-       if (p != (struct proc *)NULL)
+       p = kn->kn_ptr.p_proc;
+       if (p != PROC_NULL) {
+               kn->kn_ptr.p_proc = PROC_NULL;
                KNOTE_DETACH(&p->p_klist, kn);
+       }
 
-       thread_funnel_set(kernel_flock, funnel_state);
+       proc_klist_unlock();
 }
 
 static int
 filt_proc(struct knote *kn, long hint)
 {
-       u_int event;
-       int funnel_state;
-
-       funnel_state = thread_funnel_set(kernel_flock, TRUE);
-
        /*
-        * mask off extra data
+        * Note: a lot of bits in hint may be obtained from the knote
+        * To free some of those bits, see <rdar://problem/12592988> Freeing up
+        * bits in hint for filt_proc
         */
-       event = (u_int)hint & NOTE_PCTRLMASK;
+       /* hint is 0 when called from above */
+       if (hint != 0) {
+               u_int event;
 
-       /*
-        * if the user is interested in this event, record it.
-        */
-       if (kn->kn_sfflags & event)
-               kn->kn_fflags |= event;
+               /* ALWAYS CALLED WITH proc_klist_lock when (hint != 0) */
 
-       /*
-        * process is gone, so flag the event as finished.
-        */
-       if (event == NOTE_EXIT) {
-               kn->kn_flags |= (EV_EOF | EV_ONESHOT); 
-               thread_funnel_set(kernel_flock, funnel_state);
-               return (1);
+               /*
+                * 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;
+
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wdeprecated-declarations"
+               if ((event == NOTE_REAP) || ((event == NOTE_EXIT) && !(kn->kn_sfflags & NOTE_REAP))) {
+                       kn->kn_flags |= (EV_EOF | EV_ONESHOT);
+               }
+#pragma clang diagnostic pop
+
+
+               /*
+                * The kernel has a wrapper in place that returns the same data
+                * as is collected here, in kn_data.  Any changes to how 
+                * NOTE_EXITSTATUS and NOTE_EXIT_DETAIL are collected
+                * should also be reflected in the proc_pidnoteexit() wrapper.
+                */
+               if (event == NOTE_EXIT) {
+                       kn->kn_data = 0;
+                       if ((kn->kn_sfflags & NOTE_EXITSTATUS) != 0) {
+                               kn->kn_fflags |= NOTE_EXITSTATUS;
+                               kn->kn_data |= (hint & NOTE_PDATAMASK);
+                       }
+                       if ((kn->kn_sfflags & NOTE_EXIT_DETAIL) != 0) {
+                               kn->kn_fflags |= NOTE_EXIT_DETAIL;
+                               if ((kn->kn_ptr.p_proc->p_lflag &
+                                   P_LTERM_DECRYPTFAIL) != 0) {
+                                       kn->kn_data |= NOTE_EXIT_DECRYPTFAIL; 
+                               }
+                               if ((kn->kn_ptr.p_proc->p_lflag &
+                                   P_LTERM_JETSAM) != 0) {
+                                       kn->kn_data |= NOTE_EXIT_MEMORY;
+                                       switch (kn->kn_ptr.p_proc->p_lflag &
+                                           P_JETSAM_MASK) {
+                                               case P_JETSAM_VMPAGESHORTAGE:
+                                                       kn->kn_data |= NOTE_EXIT_MEMORY_VMPAGESHORTAGE;
+                                                       break;
+                                               case P_JETSAM_VMTHRASHING:
+                                                       kn->kn_data |= NOTE_EXIT_MEMORY_VMTHRASHING;
+                                                       break;
+                                               case P_JETSAM_FCTHRASHING:
+                                                       kn->kn_data |= NOTE_EXIT_MEMORY_FCTHRASHING;
+                                                       break;
+                                               case P_JETSAM_VNODE:
+                                                       kn->kn_data |= NOTE_EXIT_MEMORY_VNODE;
+                                                       break;
+                                               case P_JETSAM_HIWAT:
+                                                       kn->kn_data |= NOTE_EXIT_MEMORY_HIWAT;
+                                                       break;
+                                               case P_JETSAM_PID:
+                                                       kn->kn_data |= NOTE_EXIT_MEMORY_PID;
+                                                       break;
+                                               case P_JETSAM_IDLEEXIT:
+                                                       kn->kn_data |= NOTE_EXIT_MEMORY_IDLE;
+                                                       break;
+                                       }
+                               }
+                               if ((kn->kn_ptr.p_proc->p_csflags &
+                                   CS_KILLED) != 0) {
+                                       kn->kn_data |= NOTE_EXIT_CSERROR;
+                               }
+                       }
+               }
        }
 
+       /* 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)
+{
        /*
-        * process forked, and user wants to track the new process,
-        * so attach a new knote to it, and immediately report an
-        * event with the parent's pid.
+        * The note will be cleared once the information has been flushed to
+        * the client. If there is still pressure, we will be re-alerted.
         */
-       if ((event == NOTE_FORK) && (kn->kn_sfflags & NOTE_TRACK)) {
-               struct kevent kev;
-               int error;
+       kn->kn_flags |= EV_CLEAR;
+       return (vm_knote_register(kn));
+}
 
-               /*
-                * register knote with new process.
-                */
-               kev.ident = hint & NOTE_PDATAMASK;      /* pid */
-               kev.filter = kn->kn_filter;
-               kev.flags = kn->kn_flags | EV_ADD | EV_ENABLE | EV_FLAG1;
-               kev.fflags = kn->kn_sfflags;
-               kev.data = kn->kn_id;                   /* parent */
-               kev.udata = kn->kn_kevent.udata;        /* preserve udata */
-               error = kevent_register(kn->kn_kq, &kev, NULL);
-               if (error)
-                       kn->kn_fflags |= NOTE_TRACKERR;
+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;
+               }
        }
-       event = kn->kn_fflags;
-       thread_funnel_set(kernel_flock, funnel_state);
 
-       return (event != 0);
+       return (kn->kn_fflags != 0);
 }
+#endif /* VM_PRESSURE_EVENTS */
 
 /*
- * filt_timercompute - compute absolute timeout
+ * 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.
  *
- *     If the timeout is not absolute, adjust it for
- *     the current time.
+ *     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_timercompute(struct knote *kn, uint64_t *abs_time)
+filt_timervalidate(struct knote *kn)
 {
        uint64_t multiplier;
-       uint64_t raw;
+       uint64_t raw = 0;
 
        switch (kn->kn_sfflags & (NOTE_SECONDS|NOTE_USECONDS|NOTE_NSECONDS)) {
        case NOTE_SECONDS:
@@ -544,38 +739,86 @@ filt_timercompute(struct knote *kn, uint64_t *abs_time)
                multiplier = NSEC_PER_SEC / 1000;
                break;
        default:
-               return EINVAL;
+               return (EINVAL);
        }
-       nanoseconds_to_absolutetime((uint64_t)kn->kn_sdata * multiplier, &raw);
-       if (raw <= filt_timerfloor) {
-               *abs_time = 0;
-               return 0;
+
+       /* transform the slop delta(leeway) in kn_ext[1] if passed to same time scale */
+       if(kn->kn_sfflags & NOTE_LEEWAY){
+               nanoseconds_to_absolutetime((uint64_t)kn->kn_ext[1] * multiplier, &raw);
+               kn->kn_ext[1] = raw;
        }
-       if ((kn->kn_sfflags & NOTE_ABSOLUTE) == NOTE_ABSOLUTE) {
-               uint32_t seconds, nanoseconds;
+
+       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 (now >= raw + filt_timerfloor) {
-                       *abs_time = 0;
-                       return 0;
+               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]);
                }
-               raw -= now;
-       } 
-       clock_absolutetime_interval_to_deadline(raw, abs_time);
-       return 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.
+ * 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)
@@ -583,217 +826,376 @@ 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); 
+       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);
+               }
+       }
 }
 
 /*
- * data contains amount of time to sleep, in milliseconds,
- * or a pointer to a timespec structure.
- */ 
+ * 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;
-       uint64_t deadline;
        int error;
 
-       error = filt_timercompute(kn, &deadline);
-       if (error)
-               return (error);
+       callout = thread_call_allocate(filt_timerexpire, kn);
+       if (NULL == callout)
+               return (ENOMEM);
 
-       if (deadline) {
-               callout = thread_call_allocate(filt_timerexpire, kn);
-               if (NULL == callout)
-                       return (ENOMEM);
-       } else {  
-               /* handle as immediate */
-               kn->kn_sdata = 0;
-               callout = NULL;
+       filt_timerlock();
+       error = filt_timervalidate(kn);
+       if (error != 0) {
+               filt_timerunlock();
+               return (error);
        }
 
-       filt_timerlock();
-       kn->kn_hook = (caddr_t)callout;
+       kn->kn_hook = (void*)callout;
+       kn->kn_hookid = 0;
 
        /* absolute=EV_ONESHOT */
        if (kn->kn_sfflags & NOTE_ABSOLUTE)
-               kn->kn_flags |= EV_ONESHOT; 
+               kn->kn_flags |= EV_ONESHOT;
 
-       if (deadline) {
-               /* all others - if not faking immediate */
+       filt_timerupdate(kn);
+       if (kn->kn_ext[0]) {
                kn->kn_flags |= EV_CLEAR;
-               thread_call_enter_delayed(callout, deadline);
-               kn->kn_hookid = 0;
+               unsigned int timer_flags = 0;
+               if (kn->kn_sfflags & NOTE_CRITICAL)
+                       timer_flags |= THREAD_CALL_DELAY_USER_CRITICAL;
+               else if (kn->kn_sfflags & NOTE_BACKGROUND)
+                       timer_flags |= THREAD_CALL_DELAY_USER_BACKGROUND;
+               else
+                       timer_flags |= THREAD_CALL_DELAY_USER_NORMAL;
+
+               if (kn->kn_sfflags & NOTE_LEEWAY)
+                       timer_flags |= THREAD_CALL_DELAY_LEEWAY;
+
+               thread_call_enter_delayed_with_leeway(callout, NULL,
+                               kn->kn_ext[0], kn->kn_ext[1], timer_flags);
+
+               kn->kn_hookid |= TIMER_RUNNING;
        } else {
                /* fake immediate */
-               kn->kn_hookid = 1;
+               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;
-       if (callout != NULL) {
-               boolean_t cancelled;
+       filt_timercancel(kn);
 
-               /* cancel the callout if we can */
-               cancelled = thread_call_cancel(callout);
-               if (cancelled) {
-                       /* got it, just free it */
-                       kn->kn_hook = NULL;
-                       filt_timerunlock();
-                       thread_call_free(callout);
-                       return;
-               }
-               /* we have to wait for the expire routine.  */
-               kn->kn_hookid = -1;     /* we are detaching */
-               assert_wait(&kn->kn_hook, THREAD_UNINT);
-               filt_timerunlock();
-               thread_block(THREAD_CONTINUE_NULL);
-               assert(kn->kn_hook == NULL);
-               return;
-       }
-       /* nothing to do */
-       filt_timerunlock(); 
+       filt_timerunlock();
+
+       thread_call_free(callout);
 }
 
 
 
 static int
-filt_timer(struct knote *kn, __unused long hint)
+filt_timer(struct knote *kn, long hint)
 {
        int result;
-       
-       if (hint) {
-               /* real timer pop */
-               thread_call_t callout;
-               boolean_t detaching;
 
-               filt_timerlock();
-               
+       if (hint) {
+               /* real timer pop -- timer lock held by filt_timerexpire */
                kn->kn_data++;
 
-               detaching = (kn->kn_hookid < 0);
-               callout = (thread_call_t)kn->kn_hook;
-
-               if (!detaching && (kn->kn_flags & EV_ONESHOT) == 0) {
-                       uint64_t deadline;
-                       int error;
+               if (((kn->kn_hookid & TIMER_CANCELWAIT) == 0) &&
+                               ((kn->kn_flags & EV_ONESHOT) == 0)) {
 
-                       /* user input data may have changed - deal */
-                       error = filt_timercompute(kn, &deadline);
-                       if (error) {
-                               kn->kn_flags |= EV_ERROR;
-                               kn->kn_data = error;
-                       } else if (deadline == 0) {
-                               /* revert to fake immediate */
-                               kn->kn_flags &= ~EV_CLEAR;
-                               kn->kn_sdata = 0;
-                               kn->kn_hookid = 1;
-                       } else {
-                               /* keep the callout and re-arm */
-                               thread_call_enter_delayed(callout, deadline);
-                               filt_timerunlock();
-                               return 1;
-                       }
-               }
-               kn->kn_hook = NULL;
-               filt_timerunlock();
-               thread_call_free(callout);
+                       /* evaluate next time to fire */
+                       filt_timerupdate(kn);
 
-               /* if someone is waiting for timer to pop */
-               if (detaching)
-                       thread_wakeup(&kn->kn_hook);
+                       if (kn->kn_ext[0]) {
+                               unsigned int timer_flags = 0;
 
-               return 1;
-       } 
+                               /* keep the callout and re-arm */
+                               if (kn->kn_sfflags & NOTE_CRITICAL)
+                                       timer_flags |= THREAD_CALL_DELAY_USER_CRITICAL;
+                               else if (kn->kn_sfflags & NOTE_BACKGROUND)
+                                       timer_flags |= THREAD_CALL_DELAY_USER_BACKGROUND;
+                               else
+                                       timer_flags |= THREAD_CALL_DELAY_USER_NORMAL;
 
-       /* user-query */
-       filt_timerlock();
+                               if (kn->kn_sfflags & NOTE_LEEWAY)
+                                       timer_flags |= THREAD_CALL_DELAY_LEEWAY;
 
-       /* change fake timer to real if needed */
-       while (kn->kn_hookid > 0 && kn->kn_sdata > 0) {
-               int error;
+                               thread_call_enter_delayed_with_leeway(kn->kn_hook, NULL,
+                                               kn->kn_ext[0], kn->kn_ext[1], timer_flags);
 
-               /* update the fake timer (make real) */
-               kn->kn_hookid = 0;
-               kn->kn_data = 0;
-               filt_timerunlock();
-               error = filt_timerattach(kn);
-               filt_timerlock();
-               if (error) {
-                       kn->kn_flags |= EV_ERROR;
-                       kn->kn_data = error;
-                       filt_timerunlock();
-                       return 1;
+                               kn->kn_hookid |= TIMER_RUNNING;
+                       }
                }
+
+               return (1);
        }
 
-       /* if still fake, pretend it fired */
-       if (kn->kn_hookid > 0)
-               kn->kn_data = 1;
+       /* user-query */
+       filt_timerlock();
 
        result = (kn->kn_data != 0);
+
        filt_timerunlock();
-       return result;
-}
 
-static void
-filt_timerlock(void)
-{
-       lck_mtx_lock(&_filt_timerlock);
+       return (result);
 }
 
-static void
-filt_timerunlock(void)
-{
-       lck_mtx_unlock(&_filt_timerlock);
-}
 
 /*
- * JMM - placeholder for not-yet-implemented filters
- */ 
-static int
-filt_badattach(__unused struct knote *kn)
+ * 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)
 {
-       return(ENOTSUP);
-}
-
+       int error;
+       filt_timerlock();
 
-struct kqueue *
-kqueue_alloc(struct proc *p)
-{
-       struct filedesc *fdp = p->p_fd;
-       struct kqueue *kq;
+       switch (type) {
+       case EVENT_REGISTER:
+               /* cancel current call */
+               filt_timercancel(kn);
 
-       MALLOC_ZONE(kq, struct kqueue *, sizeof(struct kqueue), M_KQUEUE, M_WAITOK);
+               /* recalculate deadline */
+               kn->kn_sdata = kev->data;
+               kn->kn_sfflags = kev->fflags;
+               kn->kn_ext[0] = kev->ext[0];
+               kn->kn_ext[1] = kev->ext[1];
+
+               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]) {
+                       unsigned int timer_flags = 0;
+                       if (kn->kn_sfflags & NOTE_CRITICAL)
+                               timer_flags |= THREAD_CALL_DELAY_USER_CRITICAL;
+                       else if (kn->kn_sfflags & NOTE_BACKGROUND)
+                               timer_flags |= THREAD_CALL_DELAY_USER_BACKGROUND;
+                       else
+                               timer_flags |= THREAD_CALL_DELAY_USER_NORMAL;
+
+                       if (kn->kn_sfflags & NOTE_LEEWAY)
+                               timer_flags |= THREAD_CALL_DELAY_LEEWAY;
+
+                       thread_call_enter_delayed_with_leeway(kn->kn_hook, NULL,
+                                       kn->kn_ext[0], kn->kn_ext[1], timer_flags);
+
+                       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("%s: - invalid type (%ld)", __func__, 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("%s: - invalid type (%ld)", __func__, 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) {
-               bzero(kq, sizeof(struct kqueue));
-               lck_spin_init(&kq->kq_lock, kq_lck_grp, kq_lck_attr);
-               TAILQ_INIT(&kq->kq_head);
-               TAILQ_INIT(&kq->kq_inprocess);
-               kq->kq_fdp = fdp;
+               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);
+                       kq = NULL;
+               }
        }
 
        if (fdp->fd_knlistsize < 0) {
                proc_fdlock(p);
                if (fdp->fd_knlistsize < 0)
-                       fdp->fd_knlistsize = 0;         /* this process has had a kq */
+                       fdp->fd_knlistsize = 0; /* this process has had a kq */
                proc_fdunlock(p);
        }
 
-       return kq;
+       return (kq);
 }
 
-
 /*
  * kqueue_dealloc - detach all knotes from a kqueue and free it
  *
@@ -809,8 +1211,9 @@ kqueue_alloc(struct proc *p)
  *     Nothing locked on entry or exit.
  */
 void
-kqueue_dealloc(struct kqueue *kq, struct proc *p)
+kqueue_dealloc(struct kqueue *kq)
 {
+       struct proc *p = kq->kq_p;
        struct filedesc *fdp = p->p_fd;
        struct knote *kn;
        int i;
@@ -857,18 +1260,26 @@ kqueue_dealloc(struct kqueue *kq, struct proc *p)
                }
        }
        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);
+       FREE_ZONE(kq, sizeof (struct kqueue), M_KQUEUE);
 }
 
 int
-kqueue(struct proc *p, __unused struct kqueue_args *uap, register_t *retval)
+kqueue_body(struct proc *p, fp_allocfn_t fp_zalloc, void *cra, int32_t *retval)
 {
        struct kqueue *kq;
        struct fileproc *fp;
        int fd, error;
 
-       error = falloc(p, &fp, &fd);
+       error = falloc_withalloc(p,
+           &fp, &fd, vfs_context_current(), fp_zalloc, cra);
        if (error) {
                return (error);
        }
@@ -880,12 +1291,12 @@ kqueue(struct proc *p, __unused struct kqueue_args *uap, register_t *retval)
        }
 
        fp->f_flag = FREAD | FWRITE;
-       fp->f_type = DTYPE_KQUEUE;
        fp->f_ops = &kqueueops;
-       fp->f_data = (caddr_t)kq;
+       fp->f_data = kq;
 
        proc_fdlock(p);
-       *fdflags(p, fd) &= ~UF_RESERVED;
+       *fdflags(p, fd) |= UF_EXCLOSE;
+       procfdtbl_releasefd(p, fd, NULL);
        fp_drop(p, fd, fp, 1);
        proc_fdunlock(p);
 
@@ -894,83 +1305,97 @@ kqueue(struct proc *p, __unused struct kqueue_args *uap, register_t *retval)
 }
 
 int
-kqueue_portset_np(__unused struct proc *p, 
-                                 __unused struct kqueue_portset_np_args *uap, 
-                                 __unused register_t *retval)
-{
-               /* JMM - Placeholder for now */
-               return (ENOTSUP);
-}
-
-int
-kqueue_from_portset_np(__unused struct proc *p, 
-                                          __unused struct kqueue_from_portset_np_args *uap, 
-                                          __unused register_t *retval)
+kqueue(struct proc *p, __unused struct kqueue_args *uap, int32_t *retval)
 {
-               /* JMM - Placeholder for now */
-               return (ENOTSUP);
+       return (kqueue_body(p, fileproc_alloc_init, NULL, retval));
 }
 
 static int
-kevent_copyin(user_addr_t *addrp, struct kevent *kevp, struct proc *p)
+kevent_copyin(user_addr_t *addrp, struct kevent64_s *kevp, struct proc *p,
+    int iskev64)
 {
        int advance;
        int error;
 
-       if (IS_64BIT_PROCESS(p)) {
-               struct user_kevent kev64;
+       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);
+               advance = sizeof (kev64);
                error = copyin(*addrp, (caddr_t)&kev64, advance);
                if (error)
-                       return error;
-               kevp->ident = CAST_DOWN(uintptr_t, kev64.ident);
+                       return (error);
+               kevp->ident = kev64.ident;
                kevp->filter = kev64.filter;
                kevp->flags = kev64.flags;
                kevp->fflags = kev64.fflags;
-               kevp->data = CAST_DOWN(intptr_t, kev64.data);
+               kevp->data = kev64.data;
                kevp->udata = kev64.udata;
        } else {
-               /*
-                * compensate for legacy in-kernel kevent layout
-                * where the udata field is alredy 64-bit.
-                */
-               advance = sizeof(*kevp) + sizeof(void *) - sizeof(user_addr_t);
-               error = copyin(*addrp, (caddr_t)kevp, advance);
+               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;
+       return (error);
 }
 
 static int
-kevent_copyout(struct kevent *kevp, user_addr_t *addrp, struct proc *p)
+kevent_copyout(struct kevent64_s *kevp, user_addr_t *addrp, struct proc *p,
+    int iskev64)
 {
        int advance;
        int error;
 
-       if (IS_64BIT_PROCESS(p)) {
-               struct user_kevent kev64;
+       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.ident = (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);
+               advance = sizeof (kev64);
                error = copyout((caddr_t)&kev64, *addrp, advance);
        } else {
-               /*
-                * compensate for legacy in-kernel kevent layout
-                * where the udata field is alredy 64-bit.
-                */
-               advance = sizeof(*kevp) + sizeof(void *) - sizeof(user_addr_t);
-               error = copyout((caddr_t)kevp, *addrp, advance);
+               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;
+       return (error);
 }
 
 /*
@@ -984,7 +1409,7 @@ kevent_continue(__unused struct kqueue *kq, void *data, int error)
 {
        struct _kevent *cont_args;
        struct fileproc *fp;
-       register_t *retval;
+       int32_t *retval;
        int noutputs;
        int fd;
        struct proc *p = current_proc();
@@ -1011,43 +1436,69 @@ kevent_continue(__unused struct kqueue *kq, void *data, int 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
-kevent(struct proc *p, struct kevent_args *uap, register_t *retval)
+kevent64(struct proc *p, struct kevent64_args *uap, int32_t *retval)
 {
-       user_addr_t changelist = uap->changelist;
-       user_addr_t ueventlist = uap->eventlist;
-       int nchanges = uap->nchanges;
-       int nevents = uap->nevents;
-       int fd = uap->fd;
+       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 kevent kev; 
+       struct kevent64_s kev;
        int error, noutputs;
        struct timeval atv;
 
        /* convert timeout to absolute - if we have one */
-       if (uap->timeout != USER_ADDR_NULL) {
+       if (utimeout != USER_ADDR_NULL) {
                struct timeval rtv;
-               if ( IS_64BIT_PROCESS(p) ) {
-                       struct user_timespec ts;
-                       error = copyin( uap->timeout, &ts, sizeof(ts) );
+               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 timespec ts;
-                       error = copyin( uap->timeout, &ts, sizeof(ts) );
+                       struct user32_timespec ts;
+                       error = copyin(utimeout, &ts, sizeof(ts));
                        TIMESPEC_TO_TIMEVAL(&rtv, &ts);
                }
                if (error)
-                       return error;
+                       return (error);
                if (itimerfix(&rtv))
-                       return EINVAL;
+                       return (EINVAL);
                getmicrouptime(&atv);
                timevaladd(&atv, &rtv);
        } else {
@@ -1057,21 +1508,35 @@ kevent(struct proc *p, struct kevent_args *uap, register_t *retval)
 
        /* get a usecount for the kq itself */
        if ((error = fp_getfkq(p, fd, &fp, &kq)) != 0)
-               return(error);
+               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);
+               error = kevent_copyin(&changelist, &kev, p, iskev64);
                if (error)
                        break;
-                               
+
                kev.flags &= ~EV_SYSFLAGS;
                error = kevent_register(kq, &kev, p);
-               if (error && nevents > 0) {
+               if ((error || (kev.flags & EV_RECEIPT)) && nevents > 0) {
                        kev.flags = EV_ERROR;
                        kev.data = error;
-                       error = kevent_copyout(&kev, &ueventlist, p);
+                       error = kevent_copyout(&kev, &ueventlist, p, iskev64);
                        if (error == 0) {
                                nevents--;
                                noutputs++;
@@ -1082,52 +1547,83 @@ kevent(struct proc *p, struct kevent_args *uap, register_t *retval)
 
        /* store the continuation/completion data in the uthread */
        ut = (uthread_t)get_bsdthread_info(current_thread());
-       cont_args = (struct _kevent *)&ut->uu_state.ss_kevent;
+       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 = kevent_scan(kq, kevent_callback,
-                                   kevent_continue, cont_args,
-                                   &atv, p);
+               error = kqueue_scan(kq, kevent_callback,
+                   kevent_continue, cont_args,
+                   &atv, p);
        kevent_continue(kq, cont_args, error);
-       /* NOTREACHED */
-       return 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
+ * called with nothing locked
+ * caller holds a reference on the kqueue
  */
-
 static int
-kevent_callback(__unused struct kqueue *kq, struct kevent *kevp, void *data)
+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_arg->eventcount);
+       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());
+       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;
+               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);
 }
 
 /*
@@ -1145,9 +1641,11 @@ kevent_callback(__unused struct kqueue *kq, struct kevent *kevp, void *data)
  */
 
 int
-kevent_register(struct kqueue *kq, struct kevent *kev, struct proc *p)
+kevent_register(struct kqueue *kq, struct kevent64_s *kev,
+    __unused struct proc *ctxp)
 {
-       struct filedesc *fdp = kq->kq_fdp;
+       struct proc *p = kq->kq_p;
+       struct filedesc *fdp = p->p_fd;
        struct filterops *fops;
        struct fileproc *fp = NULL;
        struct knote *kn = NULL;
@@ -1167,12 +1665,14 @@ kevent_register(struct kqueue *kq, struct kevent *kev, struct proc *p)
                return (EINVAL);
        }
 
+restart:
        /* this iocount needs to be dropped if it is not registered */
-       if (fops->f_isfd && (error = fp_lookup(p, kev->ident, &fp, 0)) != 0)
-               return(error);
-
- restart:
        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) {
@@ -1185,7 +1685,7 @@ kevent_register(struct kqueue *kq, struct kevent *kev, struct proc *p)
                /* 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)
@@ -1217,7 +1717,7 @@ kevent_register(struct kqueue *kq, struct kevent *kev, struct proc *p)
                        kev->data = 0;
                        kn->kn_kevent = *kev;
                        kn->kn_inuse = 1;  /* for f_attach() */
-                       kn->kn_status = 0;
+                       kn->kn_status = KN_ATTACHING;
 
                        /* before anyone can find it */
                        if (kev->flags & EV_DISABLE)
@@ -1237,14 +1737,33 @@ kevent_register(struct kqueue *kq, struct kevent *kev, struct proc *p)
                         */
                        fp = NULL;
 
-                       /*
-                        * If the attach fails here, we can drop it knowing
-                        * that nobody else has a reference to the knote.
-                        */
-                       if ((error = fops->f_attach(kn)) != 0) {
+                       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;
@@ -1254,7 +1773,7 @@ kevent_register(struct kqueue *kq, struct kevent *kev, struct proc *p)
                /* existing knote - get kqueue lock */
                kqlock(kq);
                proc_fdunlock(p);
-               
+
                if (kev->flags & EV_DELETE) {
                        knote_dequeue(kn);
                        kn->kn_status |= KN_DISABLED;
@@ -1264,7 +1783,7 @@ kevent_register(struct kqueue *kq, struct kevent *kev, struct proc *p)
                        }
                        goto done;
                }
-                       
+
                /* update status flags for existing knote */
                if (kev->flags & EV_DISABLE) {
                        knote_dequeue(kn);
@@ -1275,29 +1794,47 @@ kevent_register(struct kqueue *kq, struct kevent *kev, struct proc *p)
                                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.
+                * 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 unlocked */
+               if (!kqlock2knoteusewait(kq, kn)) {
+                       /* kqueue, proc_fdlock both unlocked */
                        goto restart;
+               }
 
                /*
-                * 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.
+                * Call touch routine to notify filter of changes
+                * in filter values.
                 */
-               kn->kn_sfflags = kev->fflags;
-               kn->kn_sdata = kev->data;
-               kn->kn_kevent.udata = kev->udata;
+               if (!fops->f_isfd && fops->f_touch != NULL)
+                       fops->f_touch(kn, kev, EVENT_REGISTER);
        }
-                       
        /* still have use ref on knote */
-       if (kn->kn_fop->f_event(kn, 0)) {
+
+       /*
+        * 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);
+                       knote_activate(kn, 1);
                kqunlock(kq);
        } else {
                knote_put(kn);
@@ -1309,152 +1846,297 @@ done:
        return (error);
 }
 
+
 /*
- * kevent_process - process the triggered events in a kqueue
+ * knote_process - process a triggered event
  *
- *     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.
+ *     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
-kevent_process(struct kqueue *kq,
-              kevent_callback_t callback,
-              void *data, 
-              int *countp,
-              struct proc *p)
+knote_process(struct knote *kn,
+    kevent_callback_t callback,
+    void *data,
+    struct kqtailq *inprocessp,
+    struct proc *p)
 {
-       struct knote *kn;
-       struct kevent kev;
-       int nevents;
+       struct kqueue *kq = kn->kn_kq;
+       struct kevent64_s kev;
+       int touch;
+       int result;
        int error;
 
- restart:
-       if (kq->kq_count == 0) {
-               *countp = 0;
-               return 0;
-       }
+       /*
+        * 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;
 
-       /* if someone else is processing the queue, wait */
-       if (!TAILQ_EMPTY(&kq->kq_inprocess)) {
-               assert_wait(&kq->kq_inprocess, THREAD_UNINT);
-               kq->kq_state |= KQ_PROCWAIT;
-               kqunlock(kq);
-               thread_block(THREAD_CONTINUE_NULL);
-               kqlock(kq);
-               goto restart;
-       }
+               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);
 
-       error = 0;
-       nevents = 0;
-       while (error == 0 &&
-              (kn = TAILQ_FIRST(&kq->kq_head)) != NULL) {
+               if (revalidate || touch) {
+                       if (revalidate)
+                               knote_deactivate(kn);
 
-               /*
-                * move knote to the processed queue.
-                * this is also protected by the kq lock.
-                */
-               assert(kn->kn_tq == &kq->kq_head);
-               TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe);
-               kn->kn_tq = &kq->kq_inprocess;
-               TAILQ_INSERT_TAIL(&kq->kq_inprocess, kn, kn_tqe);
+                       /* 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);
+                               }
 
-               /*
-                * Non-EV_ONESHOT events must be re-validated.
-                *
-                * Convert our lock to a use-count and call the event's
-                * filter routine to update.
-                *
-                * If the event is dropping (or no longer valid), we
-                * already have it off the active queue, so just
-                * finish the job of deactivating it.
-                */
-               if ((kn->kn_flags & EV_ONESHOT) == 0) {
-                       int result;
+                               /*
+                                * capture the kevent data - using touch if
+                                * specified
+                                */
+                               if (result && touch) {
+                                       kn->kn_fop->f_touch(kn, &kev,
+                                           EVENT_PROCESS);
+                               }
 
-                       if (kqlock2knoteuse(kq, kn)) {
-                               
-                               /* call the filter with just a ref */
-                               result = kn->kn_fop->f_event(kn, 0);
+                               /*
+                                * 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);
+                                       }
 
-                               if (!knoteuse2kqlock(kq, kn) || result == 0) {
-                                       knote_deactivate(kn);
-                                       continue;
+                                       /*
+                                        * 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 {
-                               knote_deactivate(kn);
-                               continue;
+                               return (EJUSTRETURN);
                        }
+               } else {
+                       kev = kn->kn_kevent;
                }
+       }
 
-               /*
-                * Got a valid triggered knote with the kqueue
-                * still locked.  Snapshot the data, and determine
-                * how to dispatch the knote for future events.
-                */
-               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);
 
-               /* now what happens to it? */
-               if (kn->kn_flags & EV_ONESHOT) {
+       /*
+        * 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);
-                       if (kqlock2knotedrop(kq, kn)) {
-                               kn->kn_fop->f_detach(kn);
-                               knote_drop(kn, p);
-                       }
-               } else if (kn->kn_flags & EV_CLEAR) {
+                       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 in-process queue.  We'll
-                        * move all the remaining ones back
-                        * the kq queue and wakeup any
-                        * waiters when we are done.
-                        */
-                       kqunlock(kq);
                }
+               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);
-               nevents++;
+       /* callback to handle each event as we find it */
+       error = (callback)(kq, &kev, data);
 
-               kqlock(kq);
+       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);
+       }
+}
+
+/*
+ * 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 in-process queue back to the
+        * remaining on the inprocess queue back to the
         * kq's queue and wake up any waiters.
         */
-       while ((kn = TAILQ_FIRST(&kq->kq_inprocess)) != NULL) {
-               assert(kn->kn_tq == &kq->kq_inprocess);
-               TAILQ_REMOVE(&kq->kq_inprocess, kn, kn_tqe);
+       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);
        }
-       if (kq->kq_state & KQ_PROCWAIT) {
-               kq->kq_state &= ~KQ_PROCWAIT;
-               thread_wakeup(&kq->kq_inprocess);
-       }
+
+       kqueue_end_processing(kq);
 
        *countp = nevents;
-       return error;
+       return (error);
 }
 
 
 static void
-kevent_scan_continue(void *data, wait_result_t wait_result)
+kqueue_scan_continue(void *data, wait_result_t wait_result)
 {
-       uthread_t ut = (uthread_t)get_bsdthread_info(current_thread());
-       struct _kevent_scan * cont_args = &ut->uu_state.ss_kevent_scan;
+       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;
@@ -1463,27 +2145,30 @@ kevent_scan_continue(void *data, wait_result_t wait_result)
        switch (wait_result) {
        case THREAD_AWAKENED:
                kqlock(kq);
-               error = kevent_process(kq, cont_args->call, cont_args, &count, current_proc());
+               error = kqueue_process(kq, cont_args->call, cont_args, &count,
+                   current_proc());
                if (error == 0 && count == 0) {
-                       assert_wait_deadline(kq, THREAD_ABORTSAFE, cont_args->deadline);
+                       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(kevent_scan_continue, kq);
+                       thread_block_parameter(kqueue_scan_continue, kq);
                        /* NOTREACHED */
                }
                kqunlock(kq);
                break;
        case THREAD_TIMED_OUT:
-               error = EWOULDBLOCK; 
+               error = EWOULDBLOCK;
                break;
        case THREAD_INTERRUPTED:
                error = EINTR;
                break;
        default:
-               panic("kevent_scan_cont() - invalid wait_result (%d)", wait_result);
+               panic("%s: - invalid wait_result (%d)", __func__,
+                   wait_result);
                error = 0;
        }
-       
+
        /* call the continuation with the results */
        assert(cont_args->cont != NULL);
        (cont_args->cont)(kq, cont_args->data, error);
@@ -1491,7 +2176,7 @@ kevent_scan_continue(void *data, wait_result_t wait_result)
 
 
 /*
- * kevent_scan - scan and wait for events in a kqueue
+ * kqueue_scan - scan and wait for events in a kqueue
  *
  *     Process the triggered events in a kqueue.
  *
@@ -1505,9 +2190,9 @@ kevent_scan_continue(void *data, wait_result_t wait_result)
  */
 
 int
-kevent_scan(struct kqueue *kq, 
+kqueue_scan(struct kqueue *kq,
            kevent_callback_t callback,
-           kevent_continue_t continuation,
+           kqueue_continue_t continuation,
            void *data,
            struct timeval *atvp,
            struct proc *p)
@@ -1529,7 +2214,7 @@ kevent_scan(struct kqueue *kq,
                 * triggered.
                 */
                kqlock(kq);
-               error = kevent_process(kq, callback, data, &count, p);
+               error = kqueue_process(kq, callback, data, &count, p);
                if (error || count)
                        break; /* lock still held */
 
@@ -1538,12 +2223,11 @@ kevent_scan(struct kqueue *kq,
                        first = 0;
                        /* convert the timeout to a deadline once */
                        if (atvp->tv_sec || atvp->tv_usec) {
-                               uint32_t seconds, nanoseconds;
                                uint64_t now;
-                               
+
                                clock_get_uptime(&now);
                                nanoseconds_to_absolutetime((uint64_t)atvp->tv_sec * NSEC_PER_SEC +
-                                                           atvp->tv_usec * NSEC_PER_USEC,
+                                                           atvp->tv_usec * (long)NSEC_PER_USEC,
                                                            &deadline);
                                if (now >= deadline) {
                                        /* non-blocking call */
@@ -1558,18 +2242,20 @@ kevent_scan(struct kqueue *kq,
 
                        if (continuation) {
                                uthread_t ut = (uthread_t)get_bsdthread_info(current_thread());
-                               struct _kevent_scan *cont_args = &ut->uu_state.ss_kevent_scan;
-                               
+                               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 = kevent_scan_continue;
+                               cont = kqueue_scan_continue;
                        }
                }
 
                /* go ahead and wait */
-               assert_wait_deadline(kq, THREAD_ABORTSAFE, deadline);
+               wait_queue_assert_wait_with_leeway((wait_queue_t)kq->kq_wqs,
+                   KQ_EVENT, THREAD_ABORTSAFE, TIMEOUT_URGENCY_USER_NORMAL,
+                   deadline, 0);
                kq->kq_state |= KQ_SLEEP;
                kqunlock(kq);
                wait_result = thread_block_parameter(cont, kq);
@@ -1579,17 +2265,17 @@ kevent_scan(struct kqueue *kq,
                case THREAD_AWAKENED:
                        continue;
                case THREAD_TIMED_OUT:
-                       return EWOULDBLOCK; 
+                       return (EWOULDBLOCK);
                case THREAD_INTERRUPTED:
-                       return EINTR;
+                       return (EINTR);
                default:
-                       panic("kevent_scan - bad wait_result (%d)",
-                             wait_result);
+                       panic("%s: - bad wait_result (%d)", __func__,
+                           wait_result);
                        error = 0;
                }
        }
        kqunlock(kq);
-       return error;
+       return (error);
 }
 
 
@@ -1599,53 +2285,115 @@ kevent_scan(struct kqueue *kq,
  */
 /*ARGSUSED*/
 static int
-kqueue_read(__unused struct fileproc *fp, 
-                       __unused struct uio *uio, 
-                       __unused kauth_cred_t cred,
-                       __unused int flags, 
-                       __unused struct proc *p)
+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 kauth_cred_t cred,
-                        __unused int flags, 
-                        __unused struct proc *p)
+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 struct proc *p)
+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, struct proc *p)
+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) {
-               kqlock(kq);
-                if (kq->kq_count) {
-                       retnum = 1;
-               } else {
-                       selrecord(p, &kq->kq_sel, wql);
-                       kq->kq_state |= KQ_SEL;
-               }
+       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);
 }
 
@@ -1654,11 +2402,11 @@ kqueue_select(struct fileproc *fp, int which, void *wql, struct proc *p)
  */
 /*ARGSUSED*/
 static int
-kqueue_close(struct fileglob *fg, struct proc *p)
+kqueue_close(struct fileglob *fg, __unused vfs_context_t ctx)
 {
        struct kqueue *kq = (struct kqueue *)fg->fg_data;
 
-       kqueue_dealloc(kq, p);
+       kqueue_dealloc(kq);
        fg->fg_data = NULL;
        return (0);
 }
@@ -1670,30 +2418,92 @@ kqueue_close(struct fileglob *fg, struct proc *p)
  * that relationship is torn down.
  */
 static int
-kqueue_kqfilter(__unused struct fileproc *fp, struct knote *kn, __unused struct proc *p)
+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 (kn->kn_filter != EVFILT_READ)
+       if (parentkq == kq ||
+           kn->kn_filter != EVFILT_READ)
                return (1);
 
-       kn->kn_fop = &kqread_filtops;
+       /*
+        * 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);
-       KNOTE_ATTACH(&kq->kq_sel.si_note, kn);
+       kqueue_wakeup(kq, 1);
        kqunlock(kq);
        return (0);
 }
 
 /*ARGSUSED*/
 int
-kqueue_stat(struct fileproc *fp, struct stat *st, __unused struct proc *p)
+kqueue_stat(struct kqueue *kq, void *ub, int isstat64, proc_t p)
 {
-       struct kqueue *kq = (struct kqueue *)fp->f_data;
-
-       bzero((void *)st, sizeof(*st));
-       st->st_size = kq->kq_count;
-       st->st_blksize = sizeof(struct kevent);
-       st->st_mode = S_IFIFO;
+       kqlock(kq);
+       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 = IS_64BIT_PROCESS(p) ? sizeof(struct user64_kevent) : sizeof(struct user32_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 = IS_64BIT_PROCESS(p) ? sizeof(struct user64_kevent) : sizeof(struct user32_kevent);
+               sb->st_mode = S_IFIFO;
+       }
+       kqunlock(kq);
        return (0);
 }
 
@@ -1701,18 +2511,13 @@ kqueue_stat(struct fileproc *fp, struct stat *st, __unused struct proc *p)
  * Called with the kqueue locked
  */
 static void
-kqueue_wakeup(struct kqueue *kq)
+kqueue_wakeup(struct kqueue *kq, int closed)
 {
-
-       if (kq->kq_state & KQ_SLEEP) {
-               kq->kq_state &= ~KQ_SLEEP;
-               thread_wakeup(kq);
-       }
-       if (kq->kq_state & KQ_SEL) {
-               kq->kq_state &= ~KQ_SEL;
-               selwakeup(&kq->kq_sel);
+       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);
        }
-       KNOTE(&kq->kq_sel.si_note, 0);
 }
 
 void
@@ -1728,7 +2533,7 @@ klist_init(struct klist *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 hind) and not deadlock itself.
+ *     the hint) and not deadlock itself.
  *
  *     The object lock should also hold off pending
  *     detach/drop operations.  But we'll prevent it here
@@ -1751,7 +2556,7 @@ knote(struct klist *list, long hint)
 
                        /* if its not going away and triggered */
                        if (knoteuse2kqlock(kq, kn) && result)
-                               knote_activate(kn);
+                               knote_activate(kn, 1);
                        /* lock held again */
                }
                kqunlock(kq);
@@ -1767,7 +2572,7 @@ knote_attach(struct klist *list, struct knote *kn)
 {
        int ret = SLIST_EMPTY(list);
        SLIST_INSERT_HEAD(list, kn, kn_selnext);
-       return ret;
+       return (ret);
 }
 
 /*
@@ -1778,7 +2583,52 @@ int
 knote_detach(struct klist *list, struct knote *kn)
 {
        SLIST_REMOVE(list, kn, knote, kn_selnext);
-       return SLIST_EMPTY(list);
+       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);
+       knote_clearstayqueued(kn);
+       return ((kr != KERN_SUCCESS) ? EINVAL : 0);
 }
 
 /*
@@ -1786,7 +2636,7 @@ knote_detach(struct klist *list, struct knote *kn)
  *
  * 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.
  */
@@ -1801,6 +2651,10 @@ knote_fdclose(struct proc *p, int fd)
        while ((kn = SLIST_FIRST(list)) != NULL) {
                struct kqueue *kq = kn->kn_kq;
 
+               if (kq->kq_p != p)
+                       panic("%s: proc mismatch (kq->kq_p=%p != p=%p)",
+                           __func__, kq->kq_p, p);
+
                kqlock(kq);
                proc_fdunlock(p);
 
@@ -1815,7 +2669,7 @@ knote_fdclose(struct proc *p, int fd)
                        kn->kn_fop->f_detach(kn);
                        knote_drop(kn, p);
                }
-                       
+
                proc_fdlock(p);
 
                /* the fd tables may have changed - start over */
@@ -1825,33 +2679,41 @@ knote_fdclose(struct proc *p, int fd)
 
 /* proc_fdlock held on entry (and exit) */
 static int
-knote_fdpattach(struct knote *kn, struct filedesc *fdp, __unused struct proc *p)
+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(KN_HASHSIZE, M_KQUEUE,
+                       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);
+                           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 *));
+                           fdp->fd_knlistsize * sizeof(struct klist *));
                        bzero((caddr_t)list +
-                             fdp->fd_knlistsize * sizeof(struct klist *),
-                             (size - fdp->fd_knlistsize) * sizeof(struct klist *));
+                           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;
@@ -1869,11 +2731,13 @@ knote_fdpattach(struct knote *kn, struct filedesc *fdp, __unused struct proc *p)
  * while calling fdrop and free.
  */
 static void
-knote_drop(struct knote *kn, struct proc *p)
+knote_drop(struct knote *kn, __unused struct proc *ctxp)
 {
-        struct filedesc *fdp = p->p_fd;
        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)
@@ -1884,11 +2748,14 @@ knote_drop(struct knote *kn, struct proc *p)
        SLIST_REMOVE(list, kn, knote, kn_link);
        kqlock(kq);
        knote_dequeue(kn);
-       if (kn->kn_status & KN_DROPWAIT)
-               thread_wakeup(&kn->kn_status);
+       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);
 
@@ -1897,19 +2764,23 @@ knote_drop(struct knote *kn, struct proc *p)
 
 /* called with kqueue lock held */
 static void
-knote_activate(struct knote *kn)
+knote_activate(struct knote *kn, int propagate)
 {
        struct kqueue *kq = kn->kn_kq;
 
        kn->kn_status |= KN_ACTIVE;
        knote_enqueue(kn);
-       kqueue_wakeup(kq);
- }
+       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);
 }
@@ -1918,12 +2789,12 @@ knote_deactivate(struct knote *kn)
 static void
 knote_enqueue(struct knote *kn)
 {
-       struct kqueue *kq = kn->kn_kq;
-
-       if ((kn->kn_status & (KN_QUEUED | KN_DISABLED)) == 0) {
+       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); 
+               TAILQ_INSERT_TAIL(tq, kn, kn_tqe);
                kn->kn_status |= KN_QUEUED;
                kq->kq_count++;
        }
@@ -1935,11 +2806,10 @@ knote_dequeue(struct knote *kn)
 {
        struct kqueue *kq = kn->kn_kq;
 
-       assert((kn->kn_status & KN_DISABLED) == 0);
-       if ((kn->kn_status & KN_QUEUED) == KN_QUEUED) {
+       if ((kn->kn_status & (KN_QUEUED | KN_STAYQUEUED)) == KN_QUEUED) {
                struct kqtailq *tq = kn->kn_tq;
 
-               TAILQ_REMOVE(tq, kn, kn_tqe); 
+               TAILQ_REMOVE(tq, kn, kn_tqe);
                kn->kn_tq = &kq->kq_head;
                kn->kn_status &= ~KN_QUEUED;
                kq->kq_count--;
@@ -1949,20 +2819,29 @@ knote_dequeue(struct knote *kn)
 void
 knote_init(void)
 {
-       knote_zone = zinit(sizeof(struct knote), 8192*sizeof(struct knote), 8192, "knote zone");
+       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();
-       lck_grp_attr_setstat(kq_lck_grp_attr);
+       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();
-       lck_attr_setdefault(kq_lck_attr);
 
        /* 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
+
+#if CONFIG_MEMORYSTATUS
+       /* Initialize the memorystatus list lock */
+       memorystatus_kevent_init(kq_lck_grp, kq_lck_attr);
+#endif
 }
 SYSINIT(knote, SI_SUB_PSEUDO, SI_ORDER_ANY, knote_init, NULL)
 
@@ -1978,6 +2857,7 @@ knote_free(struct knote *kn)
        zfree(knote_zone, kn);
 }
 
+#if SOCKETS
 #include <sys/param.h>
 #include <sys/socket.h>
 #include <sys/protosw.h>
@@ -1988,294 +2868,661 @@ knote_free(struct knote *kn)
 #include <sys/sys_domain.h>
 #include <sys/syslog.h>
 
+#ifndef ROUNDUP64
+#define        ROUNDUP64(x) P2ROUNDUP((x), sizeof (u_int64_t))
+#endif
+
+#ifndef ADVANCE64
+#define        ADVANCE64(p, n) (void*)((char *)(p) + ROUNDUP64(n))
+#endif
+
+static lck_grp_attr_t *kev_lck_grp_attr;
+static lck_attr_t *kev_lck_attr;
+static lck_grp_t *kev_lck_grp;
+static decl_lck_rw_data(,kev_lck_data);
+static lck_rw_t *kev_rwlock = &kev_lck_data;
 
 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);
-
-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
+static int kev_control(struct socket *so, u_long cmd, caddr_t data,
+    struct ifnet *ifp, struct proc *p);
+static lck_mtx_t * event_getlock(struct socket *, int);
+static int event_lock(struct socket *, int, void *);
+static int event_unlock(struct socket *, int, void *);
+
+static int event_sofreelastref(struct socket *);
+static void kev_delete(struct kern_event_pcb *);
+
+static struct pr_usrreqs event_usrreqs = {
+       .pru_attach =           kev_attach,
+       .pru_control =          kev_control,
+       .pru_detach =           kev_detach,
+       .pru_soreceive =        soreceive,
 };
 
-struct protosw eventsw[] = {
-     {
-         SOCK_RAW,             &systemdomain,  SYSPROTO_EVENT,         PR_ATOMIC,
-         0,            0,              0,              0,
-         0,
-         0,            0,              0,              0,
-#if __APPLE__
-         0,
-#endif
-         &event_usrreqs,
-         0,            0,              0,
-#if __APPLE__
-         {0, 0},       0,              {0}
-#endif
-     }
+static struct protosw eventsw[] = {
+{
+       .pr_type =              SOCK_RAW,
+       .pr_protocol =          SYSPROTO_EVENT,
+       .pr_flags =             PR_ATOMIC,
+       .pr_usrreqs =           &event_usrreqs,
+       .pr_lock =              event_lock,
+       .pr_unlock =            event_unlock,
+       .pr_getlock =           event_getlock,
+}
 };
 
+__private_extern__ int kevt_getstat SYSCTL_HANDLER_ARGS;
+__private_extern__ int kevt_pcblist SYSCTL_HANDLER_ARGS;
+
+SYSCTL_NODE(_net_systm, OID_AUTO, kevt,
+       CTLFLAG_RW|CTLFLAG_LOCKED, 0, "Kernel event family");
+
+struct kevtstat kevtstat;
+SYSCTL_PROC(_net_systm_kevt, OID_AUTO, stats,
+    CTLTYPE_STRUCT | CTLFLAG_RD | CTLFLAG_LOCKED, 0, 0,
+    kevt_getstat, "S,kevtstat", "");
+
+SYSCTL_PROC(_net_systm_kevt, OID_AUTO, pcblist,
+       CTLTYPE_STRUCT | CTLFLAG_RD | CTLFLAG_LOCKED, 0, 0,
+       kevt_pcblist, "S,xkevtpcb", "");
+
+static lck_mtx_t *
+event_getlock(struct socket *so, int locktype)
+{
+#pragma unused(locktype)
+       struct kern_event_pcb *ev_pcb = (struct kern_event_pcb *)so->so_pcb;
+
+       if (so->so_pcb != NULL)  {
+               if (so->so_usecount < 0)
+                       panic("%s: so=%p usecount=%d lrh= %s\n", __func__,
+                           so, so->so_usecount, solockhistory_nr(so));
+                       /* NOTREACHED */
+       } else {
+               panic("%s: so=%p NULL NO so_pcb %s\n", __func__,
+                   so, solockhistory_nr(so));
+               /* NOTREACHED */
+       }
+       return (&ev_pcb->evp_mtx);
+}
+
+static int
+event_lock(struct socket *so, int refcount, void *lr)
+{
+       void *lr_saved;
+
+       if (lr == NULL)
+               lr_saved = __builtin_return_address(0);
+       else
+               lr_saved = lr;
+
+       if (so->so_pcb != NULL) {
+               lck_mtx_lock(&((struct kern_event_pcb *)so->so_pcb)->evp_mtx);
+       } else  {
+               panic("%s: so=%p NO PCB! lr=%p lrh= %s\n", __func__,
+                   so, lr_saved, solockhistory_nr(so));
+               /* NOTREACHED */
+       }
+
+       if (so->so_usecount < 0) {
+               panic("%s: so=%p so_pcb=%p lr=%p ref=%d lrh= %s\n", __func__,
+                   so, so->so_pcb, lr_saved, so->so_usecount,
+                   solockhistory_nr(so));
+               /* NOTREACHED */
+       }
+
+       if (refcount)
+               so->so_usecount++;
+
+       so->lock_lr[so->next_lock_lr] = lr_saved;
+       so->next_lock_lr = (so->next_lock_lr+1) % SO_LCKDBG_MAX;
+       return (0);
+}
+
+static int
+event_unlock(struct socket *so, int refcount, void *lr)
+{
+       void *lr_saved;
+       lck_mtx_t *mutex_held;
+
+       if (lr == NULL)
+               lr_saved = __builtin_return_address(0);
+       else
+               lr_saved = lr;
+
+       if (refcount)
+               so->so_usecount--;
+
+       if (so->so_usecount < 0) {
+               panic("%s: so=%p usecount=%d lrh= %s\n", __func__,
+                   so, so->so_usecount, solockhistory_nr(so));
+               /* NOTREACHED */
+       }
+       if (so->so_pcb == NULL) {
+               panic("%s: so=%p NO PCB usecount=%d lr=%p lrh= %s\n", __func__,
+                   so, so->so_usecount, (void *)lr_saved,
+                   solockhistory_nr(so));
+               /* NOTREACHED */
+       }
+       mutex_held = (&((struct kern_event_pcb *)so->so_pcb)->evp_mtx);
+
+       lck_mtx_assert(mutex_held, LCK_MTX_ASSERT_OWNED);
+       so->unlock_lr[so->next_unlock_lr] = lr_saved;
+       so->next_unlock_lr = (so->next_unlock_lr+1) % SO_LCKDBG_MAX;
+
+       if (so->so_usecount == 0) {
+               VERIFY(so->so_flags & SOF_PCBCLEARING);
+               event_sofreelastref(so);
+       } else {
+               lck_mtx_unlock(mutex_held);
+       }
+
+       return (0);
+}
+
+static int
+event_sofreelastref(struct socket *so)
+{
+       struct kern_event_pcb *ev_pcb = (struct kern_event_pcb *)so->so_pcb;
+
+       lck_mtx_assert(&(ev_pcb->evp_mtx), LCK_MTX_ASSERT_OWNED);
+
+       so->so_pcb = NULL;
+
+       /*
+        * Disable upcall in the event another thread is in kev_post_msg()
+        * appending record to the receive socket buffer, since sbwakeup()
+        * may release the socket lock otherwise.
+        */
+       so->so_rcv.sb_flags &= ~SB_UPCALL;
+       so->so_snd.sb_flags &= ~SB_UPCALL;
+       so->so_event = sonullevent;
+       lck_mtx_unlock(&(ev_pcb->evp_mtx));
+
+       lck_mtx_assert(&(ev_pcb->evp_mtx), LCK_MTX_ASSERT_NOTOWNED);
+       lck_rw_lock_exclusive(kev_rwlock);
+       LIST_REMOVE(ev_pcb, evp_link);
+       kevtstat.kes_pcbcount--;
+       kevtstat.kes_gencnt++;
+       lck_rw_done(kev_rwlock);
+       kev_delete(ev_pcb);
+
+       sofreelastref(so, 1);
+       return (0);
+}
+
+static int event_proto_count = (sizeof (eventsw) / sizeof (struct protosw));
+
 static
 struct kern_event_head kern_event_head;
 
-static u_long static_event_id = 0;
-struct domain *sysdom = &systemdomain;
+static u_int32_t static_event_id = 0;
+
+#define        EVPCB_ZONE_MAX          65536
+#define        EVPCB_ZONE_NAME         "kerneventpcb"
+static struct zone *ev_pcb_zone;
 
-static lck_grp_t               *evt_mtx_grp;
-static lck_attr_t              *evt_mtx_attr;
-static lck_grp_attr_t  *evt_mtx_grp_attr;
-lck_mtx_t                              *evt_mutex;
 /*
- * Install the protosw's for the NKE manager.  Invoked at
- *  extension load time
+ * Install the protosw's for the NKE manager.  Invoked at extension load time
  */
-int
-kern_event_init(void)
+void
+kern_event_init(struct domain *dp)
 {
-    int retval;
+       struct protosw *pr;
+       int i;
 
-    if ((retval = net_add_proto(eventsw, &systemdomain)) != 0) {
-           log(LOG_WARNING, "Can't install kernel events protocol (%d)\n", retval);
-            return(retval);
+       VERIFY(!(dp->dom_flags & DOM_INITIALIZED));
+       VERIFY(dp == systemdomain);
+
+       kev_lck_grp_attr = lck_grp_attr_alloc_init();
+       if (kev_lck_grp_attr == NULL) {
+               panic("%s: lck_grp_attr_alloc_init failed\n", __func__);
+               /* NOTREACHED */
        }
-    
-       /*
-        * allocate lock group attribute and group for kern event 
-        */
-       evt_mtx_grp_attr = lck_grp_attr_alloc_init();
 
-       evt_mtx_grp = lck_grp_alloc_init("eventlist", evt_mtx_grp_attr);
-               
-       /*
-        * allocate the lock attribute for mutexes
-        */
-       evt_mtx_attr = lck_attr_alloc_init();
-       lck_attr_setdefault(evt_mtx_attr);
-       evt_mutex = lck_mtx_alloc_init(evt_mtx_grp, evt_mtx_attr);
-       if (evt_mutex == NULL)
-                       return (ENOMEM);
-       
-    return(KERN_SUCCESS);
+       kev_lck_grp = lck_grp_alloc_init("Kernel Event Protocol",
+           kev_lck_grp_attr);
+       if (kev_lck_grp == NULL) {
+               panic("%s: lck_grp_alloc_init failed\n", __func__);
+               /* NOTREACHED */
+       }
+
+       kev_lck_attr = lck_attr_alloc_init();
+       if (kev_lck_attr == NULL) {
+               panic("%s: lck_attr_alloc_init failed\n", __func__);
+               /* NOTREACHED */
+       }
+
+       lck_rw_init(kev_rwlock, kev_lck_grp, kev_lck_attr);
+       if (kev_rwlock == NULL) {
+               panic("%s: lck_mtx_alloc_init failed\n", __func__);
+               /* NOTREACHED */
+       }
+
+       for (i = 0, pr = &eventsw[0]; i < event_proto_count; i++, pr++)
+               net_add_proto(pr, dp, 1);
+
+       ev_pcb_zone = zinit(sizeof(struct kern_event_pcb),
+           EVPCB_ZONE_MAX * sizeof(struct kern_event_pcb), 0, EVPCB_ZONE_NAME);
+       if (ev_pcb_zone == NULL) {
+               panic("%s: failed allocating ev_pcb_zone", __func__);
+               /* NOTREACHED */
+       }
+       zone_change(ev_pcb_zone, Z_EXPAND, TRUE);
+       zone_change(ev_pcb_zone, Z_CALLERACCT, TRUE);
 }
 
 static int
 kev_attach(struct socket *so, __unused int proto, __unused struct proc *p)
 {
-     int error;
-     struct kern_event_pcb  *ev_pcb;
+       int error = 0;
+       struct kern_event_pcb *ev_pcb;
 
-     error = soreserve(so, KEV_SNDSPACE, KEV_RECVSPACE);
-     if (error)
-          return error;
+       error = soreserve(so, KEV_SNDSPACE, KEV_RECVSPACE);
+       if (error != 0)
+               return (error);
 
-     MALLOC(ev_pcb, struct kern_event_pcb *, sizeof(struct kern_event_pcb), M_PCB, M_WAITOK);
-     if (ev_pcb == 0)
-         return ENOBUFS;
+       if ((ev_pcb = (struct kern_event_pcb *)zalloc(ev_pcb_zone)) == NULL) {
+               return (ENOBUFS);
+       }
+       bzero(ev_pcb, sizeof(struct kern_event_pcb));
+       lck_mtx_init(&ev_pcb->evp_mtx, kev_lck_grp, kev_lck_attr);
 
-     ev_pcb->ev_socket = so;
-     ev_pcb->vendor_code_filter = 0xffffffff;
+       ev_pcb->evp_socket = so;
+       ev_pcb->evp_vendor_code_filter = 0xffffffff;
 
-     so->so_pcb = (caddr_t) ev_pcb;
-        lck_mtx_lock(evt_mutex);
-     LIST_INSERT_HEAD(&kern_event_head, ev_pcb, ev_link);
-        lck_mtx_unlock(evt_mutex);
+       so->so_pcb = (caddr_t) ev_pcb;
+       lck_rw_lock_exclusive(kev_rwlock);
+       LIST_INSERT_HEAD(&kern_event_head, ev_pcb, evp_link);
+       kevtstat.kes_pcbcount++;
+       kevtstat.kes_gencnt++;
+       lck_rw_done(kev_rwlock);
 
-     return 0;
+       return (error);
 }
 
+static void
+kev_delete(struct kern_event_pcb *ev_pcb)
+{
+       VERIFY(ev_pcb != NULL);
+       lck_mtx_destroy(&ev_pcb->evp_mtx, kev_lck_grp);
+       zfree(ev_pcb_zone, ev_pcb);
+}
 
 static int
 kev_detach(struct socket *so)
 {
-     struct kern_event_pcb *ev_pcb = (struct kern_event_pcb *) so->so_pcb;
+       struct kern_event_pcb *ev_pcb = (struct kern_event_pcb *) so->so_pcb;
 
-     if (ev_pcb != 0) {
-               lck_mtx_lock(evt_mutex);
-               LIST_REMOVE(ev_pcb, ev_link);
-               lck_mtx_unlock(evt_mutex);
-               FREE(ev_pcb, M_PCB);
-               so->so_pcb = 0;
+       if (ev_pcb != NULL) {
+               soisdisconnected(so);
                so->so_flags |= SOF_PCBCLEARING;
-     }
+       }
 
-     return 0;
+       return (0);
 }
 
 /*
- * For now, kev_vender_code and mbuf_tags use the same
+ * For now, kev_vendor_code and mbuf_tags use the same
  * mechanism.
  */
-extern errno_t mbuf_tag_id_find_internal(const char *string, u_long *out_id,
-                                                                                int create);
-
 errno_t kev_vendor_code_find(
        const char      *string,
-       u_long          *out_vender_code)
+       u_int32_t       *out_vendor_code)
 {
        if (strlen(string) >= KEV_VENDOR_CODE_MAX_STR_LEN) {
-               return EINVAL;
+               return (EINVAL);
        }
-       return mbuf_tag_id_find_internal(string, out_vender_code, 1);
+       return (net_str_id_find_internal(string, out_vendor_code,
+           NSI_VENDOR_CODE, 1));
 }
 
-extern void mbuf_tag_id_first_last(u_long *first, u_long *last);
-
-errno_t  kev_msg_post(struct kev_msg *event_msg)
+errno_t
+kev_msg_post(struct kev_msg *event_msg)
 {
-       u_long  min_vendor, max_vendor;
-       
-       mbuf_tag_id_first_last(&min_vendor, &max_vendor);
-       
+       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 */
+               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;
+           event_msg->vendor_code > max_vendor) {
+               OSIncrementAtomic64((SInt64 *)&kevtstat.kes_badvendor);
+               return (EINVAL);
        }
-       
-       return kev_post_msg(event_msg);
+       return (kev_post_msg(event_msg));
 }
-       
 
-int  kev_post_msg(struct kev_msg *event_msg)
+int
+kev_post_msg(struct kev_msg *event_msg)
 {
-     struct mbuf *m, *m2;
-     struct kern_event_pcb  *ev_pcb;
-     struct kern_event_msg  *ev;
-     char              *tmp;
-     unsigned long     total_size;
-     int               i;
+       struct mbuf *m, *m2;
+       struct kern_event_pcb *ev_pcb;
+       struct kern_event_msg *ev;
+       char *tmp;
+       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)
-         return ENOBUFS;
-
-     ev = mtod(m, struct kern_event_msg *);
-     total_size = KEV_MSG_HEADER_SIZE;
-
-     tmp = (char *) &ev->event_data[0];
-     for (i = 0; i < 5; i++) {
-         if (event_msg->dv[i].data_length == 0)
-              break;
-
-         total_size += event_msg->dv[i].data_length;
-         bcopy(event_msg->dv[i].data_ptr, tmp, 
-               event_msg->dv[i].data_length);
-         tmp += event_msg->dv[i].data_length;
-     }
-
-     ev->id = ++static_event_id;
-     ev->total_size   = total_size;
-     ev->vendor_code  = event_msg->vendor_code;
-     ev->kev_class    = event_msg->kev_class;
-     ev->kev_subclass = event_msg->kev_subclass;
-     ev->event_code   = event_msg->event_code;
-
-     m->m_len = total_size;
-     lck_mtx_lock(evt_mutex);
-     for (ev_pcb = LIST_FIRST(&kern_event_head); 
-         ev_pcb; 
-         ev_pcb = LIST_NEXT(ev_pcb, ev_link)) {
-
-         if (ev_pcb->vendor_code_filter != KEV_ANY_VENDOR) {
-              if (ev_pcb->vendor_code_filter != ev->vendor_code)
-                   continue;
-
-              if (ev_pcb->class_filter != KEV_ANY_CLASS) {
-                   if (ev_pcb->class_filter != ev->kev_class)
-                        continue;
-
-                   if ((ev_pcb->subclass_filter != KEV_ANY_SUBCLASS) &&
-                       (ev_pcb->subclass_filter != ev->kev_subclass))
-                        continue;
-              }
-         }
-
-         m2 = m_copym(m, 0, m->m_len, M_NOWAIT);
-         if (m2 == 0) {
-              m_free(m);
-                  lck_mtx_unlock(evt_mutex);
-              return ENOBUFS;
-         }
-         socket_lock(ev_pcb->ev_socket, 1);
-         if (sbappendrecord(&ev_pcb->ev_socket->so_rcv, m2))
-                 sorwakeup(ev_pcb->ev_socket);
-         socket_unlock(ev_pcb->ev_socket, 1);
-     }
-
-     m_free(m);
-     lck_mtx_unlock(evt_mutex);
-     return 0;
+               OSIncrementAtomic64((SInt64 *)&kevtstat.kes_toobig);
+               return (EMSGSIZE);
+       }
+
+       m = m_get(M_DONTWAIT, MT_DATA);
+       if (m == 0) {
+               OSIncrementAtomic64((SInt64 *)&kevtstat.kes_nomem);
+               return (ENOMEM);
+       }
+       ev = mtod(m, struct kern_event_msg *);
+       total_size = KEV_MSG_HEADER_SIZE;
+
+       tmp = (char *) &ev->event_data[0];
+       for (i = 0; i < 5; i++) {
+               if (event_msg->dv[i].data_length == 0)
+                       break;
+
+               total_size += event_msg->dv[i].data_length;
+               bcopy(event_msg->dv[i].data_ptr, tmp,
+                   event_msg->dv[i].data_length);
+               tmp += event_msg->dv[i].data_length;
+       }
+
+       ev->id = ++static_event_id;
+       ev->total_size   = total_size;
+       ev->vendor_code  = event_msg->vendor_code;
+       ev->kev_class    = event_msg->kev_class;
+       ev->kev_subclass = event_msg->kev_subclass;
+       ev->event_code   = event_msg->event_code;
+
+       m->m_len = total_size;
+       lck_rw_lock_shared(kev_rwlock);
+       for (ev_pcb = LIST_FIRST(&kern_event_head);
+           ev_pcb;
+           ev_pcb = LIST_NEXT(ev_pcb, evp_link)) {
+               lck_mtx_lock(&ev_pcb->evp_mtx);
+               if (ev_pcb->evp_socket->so_pcb == NULL) {
+                       lck_mtx_unlock(&ev_pcb->evp_mtx);
+                       continue;
+               }
+               if (ev_pcb->evp_vendor_code_filter != KEV_ANY_VENDOR) {
+                       if (ev_pcb->evp_vendor_code_filter != ev->vendor_code) {
+                               lck_mtx_unlock(&ev_pcb->evp_mtx);
+                               continue;
+                       }
+
+                       if (ev_pcb->evp_class_filter != KEV_ANY_CLASS) {
+                               if (ev_pcb->evp_class_filter != ev->kev_class) {
+                                       lck_mtx_unlock(&ev_pcb->evp_mtx);
+                                       continue;
+                               }
+
+                               if ((ev_pcb->evp_subclass_filter !=
+                                   KEV_ANY_SUBCLASS) &&
+                                   (ev_pcb->evp_subclass_filter !=
+                                   ev->kev_subclass)) {
+                                       lck_mtx_unlock(&ev_pcb->evp_mtx);
+                                       continue;
+                               }
+                       }
+               }
+
+               m2 = m_copym(m, 0, m->m_len, M_NOWAIT);
+               if (m2 == 0) {
+                       OSIncrementAtomic64((SInt64 *)&kevtstat.kes_nomem);
+                       m_free(m);
+                       lck_mtx_unlock(&ev_pcb->evp_mtx);
+                       lck_rw_done(kev_rwlock);
+                       return (ENOMEM);
+               }
+               if (sbappendrecord(&ev_pcb->evp_socket->so_rcv, m2)) {
+                       /*
+                        * We use "m" for the socket stats as it would be
+                        * unsafe to use "m2"
+                        */
+                       so_inc_recv_data_stat(ev_pcb->evp_socket,
+                           1, m->m_len, SO_TC_BE);
+
+                       sorwakeup(ev_pcb->evp_socket);
+                       OSIncrementAtomic64((SInt64 *)&kevtstat.kes_posted);
+               } else {
+                       OSIncrementAtomic64((SInt64 *)&kevtstat.kes_fullsock);
+               }
+               lck_mtx_unlock(&ev_pcb->evp_mtx);
+       }
+       m_free(m);
+       lck_rw_done(kev_rwlock);
+
+       return (0);
 }
 
 static int
-kev_control(struct socket *so, 
-                       u_long cmd, 
-                       caddr_t data, 
-                       __unused struct ifnet *ifp, 
-                       __unused struct proc *p)
+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;
        struct kern_event_pcb  *ev_pcb;
        struct kev_vendor_code *kev_vendor;
-       u_long  *id_value = (u_long *) data;
-       
-       
+       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;
+                       ev_pcb->evp_vendor_code_filter = kev_req->vendor_code;
+                       ev_pcb->evp_class_filter = kev_req->kev_class;
+                       ev_pcb->evp_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;
+                       kev_req->vendor_code = ev_pcb->evp_vendor_code_filter;
+                       kev_req->kev_class   = ev_pcb->evp_class_filter;
+                       kev_req->kev_subclass = ev_pcb->evp_subclass_filter;
                        break;
-               
                case SIOCGKEVVENDOR:
-                       kev_vendor = (struct kev_vendor_code*)data;
-                       
+                       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 mbuf_tag_id_find_internal(kev_vendor->vendor_string,
-                                                                                        &kev_vendor->vendor_code, 0);
-               
+                       return (net_str_id_find_internal(kev_vendor->vendor_string,
+                           &kev_vendor->vendor_code, NSI_VENDOR_CODE, 0));
                default:
-                       return ENOTSUP;
+                       return (ENOTSUP);
        }
-       
-       return 0;
+
+       return (0);
 }
 
+int
+kevt_getstat SYSCTL_HANDLER_ARGS
+{
+#pragma unused(oidp, arg1, arg2)
+       int error = 0;
 
+       lck_rw_lock_shared(kev_rwlock);
 
+       if (req->newptr != USER_ADDR_NULL) {
+               error = EPERM;
+               goto done;
+       }
+       if (req->oldptr == USER_ADDR_NULL) {
+               req->oldidx = sizeof(struct kevtstat);
+               goto done;
+       }
+
+       error = SYSCTL_OUT(req, &kevtstat,
+           MIN(sizeof(struct kevtstat), req->oldlen));
+done:
+       lck_rw_done(kev_rwlock);
+
+       return (error);
+}
+
+__private_extern__ int
+kevt_pcblist SYSCTL_HANDLER_ARGS
+{
+#pragma unused(oidp, arg1, arg2)
+       int error = 0;
+       int n, i;
+       struct xsystmgen xsg;
+       void *buf = NULL;
+       size_t item_size = ROUNDUP64(sizeof (struct xkevtpcb)) +
+               ROUNDUP64(sizeof (struct xsocket_n)) +
+               2 * ROUNDUP64(sizeof (struct xsockbuf_n)) +
+               ROUNDUP64(sizeof (struct xsockstat_n));
+       struct kern_event_pcb  *ev_pcb;
+
+       buf = _MALLOC(item_size, M_TEMP, M_WAITOK | M_ZERO);
+       if (buf == NULL)
+               return (ENOMEM);
 
+       lck_rw_lock_shared(kev_rwlock);
+
+       n = kevtstat.kes_pcbcount;
+
+       if (req->oldptr == USER_ADDR_NULL) {
+               req->oldidx = (n + n/8) * item_size;
+               goto done;
+       }
+       if (req->newptr != USER_ADDR_NULL) {
+               error = EPERM;
+               goto done;
+       }
+       bzero(&xsg, sizeof (xsg));
+       xsg.xg_len = sizeof (xsg);
+       xsg.xg_count = n;
+       xsg.xg_gen = kevtstat.kes_gencnt;
+       xsg.xg_sogen = so_gencnt;
+       error = SYSCTL_OUT(req, &xsg, sizeof (xsg));
+       if (error) {
+               goto done;
+       }
+       /*
+        * We are done if there is no pcb
+        */
+       if (n == 0) {
+               goto done;
+       }
+
+       i = 0;
+       for (i = 0, ev_pcb = LIST_FIRST(&kern_event_head);
+           i < n && ev_pcb != NULL;
+           i++, ev_pcb = LIST_NEXT(ev_pcb, evp_link)) {
+               struct xkevtpcb *xk = (struct xkevtpcb *)buf;
+               struct xsocket_n *xso = (struct xsocket_n *)
+                       ADVANCE64(xk, sizeof (*xk));
+               struct xsockbuf_n *xsbrcv = (struct xsockbuf_n *)
+                       ADVANCE64(xso, sizeof (*xso));
+               struct xsockbuf_n *xsbsnd = (struct xsockbuf_n *)
+                       ADVANCE64(xsbrcv, sizeof (*xsbrcv));
+               struct xsockstat_n *xsostats = (struct xsockstat_n *)
+                       ADVANCE64(xsbsnd, sizeof (*xsbsnd));
+
+               bzero(buf, item_size);
+
+               lck_mtx_lock(&ev_pcb->evp_mtx);
+
+               xk->kep_len = sizeof(struct xkevtpcb);
+               xk->kep_kind = XSO_EVT;
+               xk->kep_evtpcb = (uint64_t)VM_KERNEL_ADDRPERM(ev_pcb);
+               xk->kep_vendor_code_filter = ev_pcb->evp_vendor_code_filter;
+               xk->kep_class_filter = ev_pcb->evp_class_filter;
+               xk->kep_subclass_filter = ev_pcb->evp_subclass_filter;
+
+               sotoxsocket_n(ev_pcb->evp_socket, xso);
+               sbtoxsockbuf_n(ev_pcb->evp_socket ?
+                       &ev_pcb->evp_socket->so_rcv : NULL, xsbrcv);
+               sbtoxsockbuf_n(ev_pcb->evp_socket ?
+                       &ev_pcb->evp_socket->so_snd : NULL, xsbsnd);
+               sbtoxsockstat_n(ev_pcb->evp_socket, xsostats);
+
+               lck_mtx_unlock(&ev_pcb->evp_mtx);
+
+               error = SYSCTL_OUT(req, buf, item_size);
+       }
+
+       if (error == 0) {
+               /*
+                * Give the user an updated idea of our state.
+                * If the generation differs from what we told
+                * her before, she knows that something happened
+                * while we were processing this request, and it
+                * might be necessary to retry.
+                */
+               bzero(&xsg, sizeof (xsg));
+               xsg.xg_len = sizeof (xsg);
+               xsg.xg_count = n;
+               xsg.xg_gen = kevtstat.kes_gencnt;
+               xsg.xg_sogen = so_gencnt;
+               error = SYSCTL_OUT(req, &xsg, sizeof (xsg));
+               if (error) {
+                       goto done;
+               }
+       }
+
+done:
+       lck_rw_done(kev_rwlock);
+
+       return (error);
+}
+
+#endif /* SOCKETS */
+
+
+int
+fill_kqueueinfo(struct kqueue *kq, struct kqueue_info * kinfo)
+{
+       struct vinfo_stat * st;
+
+       st = &kinfo->kq_stat;
+
+       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);
+}
+
+
+void
+knote_markstayqueued(struct knote *kn)
+{
+       kqlock(kn->kn_kq);
+       kn->kn_status |= KN_STAYQUEUED;
+       knote_enqueue(kn);
+       kqunlock(kn->kn_kq);
+}
+
+void
+knote_clearstayqueued(struct knote *kn)
+{
+       kqlock(kn->kn_kq);
+       kn->kn_status &= ~KN_STAYQUEUED;
+       knote_dequeue(kn);
+       kqunlock(kn->kn_kq);
+}