 @@ -1,647 +1,649 @@
-.\"	$NetBSD: kqueue.2,v 1.33 2012/11/24 15:16:52 christos Exp $
+.\"	$NetBSD: kqueue.2,v 1.33.8.1 2015/04/14 04:39:58 snj Exp $
 .\"
 .\" Copyright (c) 2000 Jonathan Lemon
 .\" All rights reserved.
 .\"
 .\" Copyright (c) 2001, 2002, 2003 The NetBSD Foundation, Inc.
 .\" All rights reserved.
 .\"
 .\" Portions of this documentation is derived from text contributed by
 .\" Luke Mewburn.
 .\"
 .\" Redistribution and use in source and binary forms, with or without
 .\" modification, are permitted provided that the following conditions
 .\" are met:
 .\" 1. Redistributions of source code must retain the above copyright
 .\"    notice, this list of conditions and the following disclaimer.
 .\" 2. Redistributions in binary form must reproduce the above copyright
 .\"    notice, this list of conditions and the following disclaimer in the
 .\"    documentation and/or other materials provided with the distribution.
 .\"
 .\" THIS SOFTWARE IS PROVIDED ``AS IS'' AND
 .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 .\" ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
 .\" $FreeBSD: src/lib/libc/sys/kqueue.2,v 1.22 2001/06/27 19:55:57 dd Exp $
 .\"
-.Dd November 24, 2012
+.Dd March 2, 2015
 .Dt KQUEUE 2
 .Os
 .Sh NAME
 .Nm kqueue ,
 .Nm kqueue1 ,
 .Nm kevent
 .Nd kernel event notification mechanism
 .Sh LIBRARY
 .Lb libc
 .Sh SYNOPSIS
 .In sys/event.h
 .In sys/time.h
 .Ft int
 .Fn kqueue "void"
 .Ft int
 .Fn kqueue1 "int flags"
 .Ft int
 .Fn kevent "int kq" "const struct kevent *changelist" "size_t nchanges" "struct kevent *eventlist" "size_t nevents" "const struct timespec *timeout"
 .Fn EV_SET "\*[Am]kev" ident filter flags fflags data udata
 .Sh DESCRIPTION
 .Fn kqueue
 provides a generic method of notifying the user when an event
 happens or a condition holds, based on the results of small
 pieces of kernel code termed filters.
 A kevent is identified by the (ident, filter) pair; there may only
 be one unique kevent per kqueue.
 .Pp
 The filter is executed upon the initial registration of a kevent
 in order to detect whether a preexisting condition is present, and is also
 executed whenever an event is passed to the filter for evaluation.
 If the filter determines that the condition should be reported,
 then the kevent is placed on the kqueue for the user to retrieve.
 .Pp
 The filter is also run when the user attempts to retrieve the kevent
 from the kqueue.
 If the filter indicates that the condition that triggered
 the event no longer holds, the kevent is removed from the kqueue and
 is not returned.
 .Pp
 Multiple events which trigger the filter do not result in multiple
 kevents being placed on the kqueue; instead, the filter will aggregate
 the events into a single struct kevent.
 Calling
 .Fn close
 on a file descriptor will remove any kevents that reference the descriptor.
 .Pp
 .Fn kqueue
 creates a new kernel event queue and returns a descriptor.
 .Pp
 The
 .Fn kqueue1
 also allows to set the following
 .Fa flags
 on the returned file descriptor:
 .Bl -column O_NONBLOCK -offset indent
 .It Dv O_CLOEXEC
 Set the close on exec property.
 .It Dv O_NONBLOCK
 Sets non-blocking I/O.
 .It Dv O_NOSIGPIPE
 Return
 .Er EPIPE
 instead of raising
 .Dv SIGPIPE .
 .El
 The queue is not inherited by a child created with
 .Xr fork 2 .
 .\" However, if
 .\" .Xr rfork 2
 .\" is called without the
 .\" .Dv RFFDG
 .\" flag, then the descriptor table is shared,
 .\" which will allow sharing of the kqueue between two processes.
 .Pp
 .Fn kevent
 is used to register events with the queue, and return any pending
 events to the user.
 .Fa changelist
 is a pointer to an array of
 .Va kevent
 structures, as defined in
 .In sys/event.h .
 All changes contained in the
 .Fa changelist
 are applied before any pending events are read from the queue.
 .Fa nchanges
 gives the size of
 .Fa changelist .
 .Fa eventlist
 is a pointer to an array of kevent structures.
 .Fa nevents
 determines the size of
 .Fa eventlist .
 If
 .Fa timeout
 is a
 .No non- Ns Dv NULL
 pointer, it specifies a maximum interval to wait
 for an event, which will be interpreted as a struct timespec.
 If
 .Fa timeout
 is a
 .Dv NULL
 pointer,
 .Fn kevent
 waits indefinitely.
 To effect a poll, the
 .Fa timeout
 argument should be
 .No non- Ns Dv NULL ,
 pointing to a zero-valued
 .Va timespec
 structure.
 The same array may be used for the
 .Fa changelist
 and
 .Fa eventlist .
 .Pp
 .Fn EV_SET
 is a macro which is provided for ease of initializing a
 kevent structure.
 .Pp
 The
 .Va kevent
 structure is defined as:
 .Bd -literal
 struct kevent {
 	uintptr_t ident;	/* identifier for this event */
 	uint32_t  filter;	/* filter for event */
 	uint32_t  flags;	/* action flags for kqueue */
 	uint32_t  fflags;	/* filter flag value */
 	int64_t   data;		/* filter data value */
 	intptr_t  udata;	/* opaque user data identifier */
 };
 .Ed
 .Pp
 The fields of
 .Fa struct kevent
 are:
 .Bl -tag -width XXXfilter -offset indent
 .It ident
 Value used to identify this event.
 The exact interpretation is determined by the attached filter,
 but often is a file descriptor.
 .It filter
 Identifies the kernel filter used to process this event.
 There are pre-defined system filters (which are described below), and
 other filters may be added by kernel subsystems as necessary.
 .It flags
 Actions to perform on the event.
 .It fflags
 Filter-specific flags.
 .It data
 Filter-specific data value.
 .It udata
 Opaque user-defined value passed through the kernel unchanged.
 .El
 .Pp
 The
 .Va flags
 field can contain the following values:
 .Bl -tag -width XXXEV_ONESHOT -offset indent
 .It EV_ADD
 Adds the event to the kqueue.
 Re-adding an existing event will modify the parameters of the original
 event, and not result in a duplicate entry.
 Adding an event automatically enables it,
 unless overridden by the EV_DISABLE flag.
 .It EV_ENABLE
 Permit
 .Fn kevent
 to return the event if it is triggered.
 .It EV_DISABLE
 Disable the event so
 .Fn kevent
 will not return it.
 The filter itself is not disabled.
 .It EV_DELETE
 Removes the event from the kqueue.
 Events which are attached to file descriptors are automatically deleted
 on the last close of the descriptor.
 .It EV_ONESHOT
 Causes the event to return only the first occurrence of the filter
 being triggered.
 After the user retrieves the event from the kqueue, it is deleted.
 .It EV_CLEAR
 After the event is retrieved by the user, its state is reset.
 This is useful for filters which report state transitions
 instead of the current state.
 Note that some filters may automatically set this flag internally.
 .It EV_EOF
 Filters may set this flag to indicate filter-specific EOF condition.
 .It EV_ERROR
 See
 .Sx RETURN VALUES
 below.
 .El
 .Ss Filters
 Filters are identified by a number.
 There are two types of filters; pre-defined filters which
 are described below, and third-party filters that may be added with
 .Xr kfilter_register 9
 by kernel sub-systems, third-party device drivers, or loadable
 kernel modules.
 .Pp
 As a third-party filter is referenced by a well-known name instead
 of a statically assigned number, two
 .Xr ioctl 2 Ns s
 are supported on the file descriptor returned by
 .Fn kqueue
 to map a filter name to a filter number, and vice-versa (passing
 arguments in a structure described below):
 .Bl -tag -width KFILTER_BYFILTER -offset indent
 .It KFILTER_BYFILTER
 Map
 .Va filter
 to
 .Va name ,
 which is of size
 .Va len .
 .It KFILTER_BYNAME
 Map
 .Va name
 to
 .Va filter .
 .Va len
 is ignored.
 .El
 .Pp
 The following structure is used to pass arguments in and out of the
 .Xr ioctl 2 :
 .Bd -literal -offset indent
 struct kfilter_mapping {
 	char	 *name;		/* name to lookup or return */
 	size_t	 len;		/* length of name */
 	uint32_t filter;	/* filter to lookup or return */
 };
 .Ed
 .Pp
 Arguments may be passed to and from the filter via the
 .Va fflags
 and
 .Va data
 fields in the kevent structure.
 .Pp
 The predefined system filters are:
 .Bl -tag -width EVFILT_SIGNAL
 .It EVFILT_READ
 Takes a descriptor as the identifier, and returns whenever
 there is data available to read.
 The behavior of the filter is slightly different depending
 on the descriptor type.
 .Pp
 .Bl -tag -width 2n
 .It Sockets
 Sockets which have previously been passed to
 .Fn listen
 return when there is an incoming connection pending.
 .Va data
 contains the size of the listen backlog (i.e., the number of
 connections ready to be accepted with
 .Xr accept 2 . )
 .Pp
 Other socket descriptors return when there is data to be read,
 subject to the
 .Dv SO_RCVLOWAT
 value of the socket buffer.
 This may be overridden with a per-filter low water mark at the
 time the filter is added by setting the
 NOTE_LOWAT
 flag in
 .Va fflags ,
 and specifying the new low water mark in
 .Va data .
 On return,
 .Va data
 contains the number of bytes in the socket buffer.
 .Pp
 If the read direction of the socket has shutdown, then the filter
 also sets EV_EOF in
 .Va flags ,
 and returns the socket error (if any) in
 .Va fflags .
 It is possible for EOF to be returned (indicating the connection is gone)
 while there is still data pending in the socket buffer.
 .It Vnodes
 Returns when the file pointer is not at the end of file.
 .Va data
 contains the offset from current position to end of file,
 and may be negative.
 .It "Fifos, Pipes"
 Returns when there is data to read;
 .Va data
 contains the number of bytes available.
 .Pp
 When the last writer disconnects, the filter will set EV_EOF in
 .Va flags .
 This may be cleared by passing in EV_CLEAR, at which point the
 filter will resume waiting for data to become available before
 returning.
 .El
 .It EVFILT_WRITE
 Takes a descriptor as the identifier, and returns whenever
 it is possible to write to the descriptor.
 For sockets, pipes, fifos, and ttys,
 .Va data
 will contain the amount of space remaining in the write buffer.
 The filter will set EV_EOF when the reader disconnects, and for
 the fifo case, this may be cleared by use of EV_CLEAR.
 Note that this filter is not supported for vnodes.
 .Pp
 For sockets, the low water mark and socket error handling is
 identical to the EVFILT_READ case.
 .It EVFILT_AIO
 This is not implemented in
 .Nx .
 .ig
 The sigevent portion of the AIO request is filled in, with
 .Va sigev_notify_kqueue
 containing the descriptor of the kqueue that the event should
 be attached to,
 .Va sigev_value
 containing the udata value, and
 .Va sigev_notify
 set to SIGEV_EVENT.
 When the aio_* function is called, the event will be registered
 with the specified kqueue, and the
 .Va ident
 argument set to the
 .Fa struct aiocb
 returned by the aio_* function.
 The filter returns under the same conditions as aio_error.
 .Pp
 Alternatively, a kevent structure may be initialized, with
 .Va ident
 containing the descriptor of the kqueue, and the
 address of the kevent structure placed in the
 .Va aio_lio_opcode
 field of the AIO request.
 However, this approach will not work on
 architectures with 64-bit pointers, and should be considered deprecated.
 ..
 .It EVFILT_VNODE
 Takes a file descriptor as the identifier and the events to watch for in
 .Va fflags ,
 and returns when one or more of the requested events occurs on the descriptor.
 The events to monitor are:
 .Bl -tag -width XXNOTE_RENAME
 .It NOTE_DELETE
 .Fn unlink
 was called on the file referenced by the descriptor.
 .It NOTE_WRITE
 A write occurred on the file referenced by the descriptor.
 .It NOTE_EXTEND
 The file referenced by the descriptor was extended.
 .It NOTE_ATTRIB
 The file referenced by the descriptor had its attributes changed.
 .It NOTE_LINK
 The link count on the file changed.
 .It NOTE_RENAME
 The file referenced by the descriptor was renamed.
 .It NOTE_REVOKE
 Access to the file was revoked via
 .Xr revoke 2
 or the underlying fileystem was unmounted.
 .El
 .Pp
 On return,
 .Va fflags
 contains the events which triggered the filter.
 .It EVFILT_PROC
 Takes the process ID to monitor as the identifier and the events to watch for
 in
 .Va fflags ,
 and returns when the process performs one or more of the requested events.
 If a process can normally see another process, it can attach an event to it.
 The events to monitor are:
 .Bl -tag -width XXNOTE_TRACKERR
 .It NOTE_EXIT
 The process has exited.
 The exit code of the process is stored in
 .Va data .
 .It NOTE_FORK
 The process has called
 .Fn fork .
 .It NOTE_EXEC
 The process has executed a new process via
 .Xr execve 2
 or similar call.
 .It NOTE_TRACK
 Follow a process across
 .Fn fork
 calls.
 The parent process will return with NOTE_TRACK set in the
 .Va fflags
 field, while the child process will return with NOTE_CHILD set in
 .Va fflags
 and the parent PID in
 .Va data .
 .It NOTE_TRACKERR
 This flag is returned if the system was unable to attach an event to
 the child process, usually due to resource limitations.
 .El
 .Pp
 On return,
 .Va fflags
 contains the events which triggered the filter.
 .It EVFILT_SIGNAL
 Takes the signal number to monitor as the identifier and returns
 when the given signal is delivered to the current process.
 This coexists with the
 .Fn signal
 and
 .Fn sigaction
 facilities, and has a lower precedence.
 The filter will record
 all attempts to deliver a signal to a process, even if the signal has
 been marked as SIG_IGN.
 Event notification happens after normal signal delivery processing.
 .Va data
 returns the number of times the signal has occurred since the last call to
 .Fn kevent .
 This filter automatically sets the EV_CLEAR flag internally.
 .It EVFILT_TIMER
 Establishes an arbitrary timer identified by
 .Va ident .
 When adding a timer,
 .Va data
 specifies the timeout period in milliseconds.
 The timer will be periodic unless EV_ONESHOT is specified.
 On return,
 .Va data
 contains the number of times the timeout has expired since the last call to
 .Fn kevent .
 This filter automatically sets the EV_CLEAR flag internally.
 .El
 .Sh RETURN VALUES
 .Fn kqueue
 creates a new kernel event queue and returns a file descriptor.
 If there was an error creating the kernel event queue, a value of \-1 is
 returned and errno set.
 .Pp
 .Fn kevent
 returns the number of events placed in the
 .Fa eventlist ,
 up to the value given by
 .Fa nevents .
 If an error occurs while processing an element of the
 .Fa changelist
 and there is enough room in the
 .Fa eventlist ,
 then the event will be placed in the
 .Fa eventlist
 with
 .Dv EV_ERROR
 set in
 .Va flags
 and the system error in
 .Va data .
 Otherwise,
 .Dv \-1
 will be returned, and
 .Dv errno
 will be set to indicate the error condition.
 If the time limit expires, then
 .Fn kevent
 returns 0.
 .Sh EXAMPLES
 The following example program monitors a file (provided to it as the first
 argument) and prints information about some common events it receives
 notifications for:
 .Bd -literal -offset indent
 #include \*[Lt]sys/types.h\*[Gt]
 #include \*[Lt]sys/event.h\*[Gt]
 #include \*[Lt]sys/time.h\*[Gt]
 #include \*[Lt]stdio.h\*[Gt]
 #include \*[Lt]unistd.h\*[Gt]
 #include \*[Lt]stdlib.h\*[Gt]
 #include \*[Lt]fcntl.h\*[Gt]
 #include \*[Lt]err.h\*[Gt]
 int
 main(int argc, char *argv[])
+{
         int fd, kq, nev;
         struct kevent ev;
         static const struct timespec tout = { 1, 0 };
         if ((fd = open(argv[1], O_RDONLY)) == -1)
                 err(1, "Cannot open `%s'", argv[1]);
         if ((kq = kqueue()) == -1)
                 err(1, "Cannot create kqueue");
         EV_SET(\*[Am]ev, fd, EVFILT_VNODE, EV_ADD | EV_ENABLE | EV_CLEAR,
             NOTE_DELETE|NOTE_WRITE|NOTE_EXTEND|NOTE_ATTRIB|NOTE_LINK|
             NOTE_RENAME|NOTE_REVOKE, 0, 0);
         if (kevent(kq, \*[Am]ev, 1, NULL, 0, \*[Am]tout) == -1)
                 err(1, "kevent");
         for (;;) {
                 nev = kevent(kq, NULL, 0, \*[Am]ev, 1, \*[Am]tout);
                 if (nev == -1)
                         err(1, "kevent");
                 if (nev == 0)
                         continue;
                 if (ev.fflags \*[Am] NOTE_DELETE) {
                         printf("deleted ");
                         ev.fflags \*[Am]= ~NOTE_DELETE;
+                }
                 if (ev.fflags \*[Am] NOTE_WRITE) {
                         printf("written ");
                         ev.fflags \*[Am]= ~NOTE_WRITE;
+                }
                 if (ev.fflags \*[Am] NOTE_EXTEND) {
                         printf("extended ");
                         ev.fflags \*[Am]= ~NOTE_EXTEND;
+                }
                 if (ev.fflags \*[Am] NOTE_ATTRIB) {
                         printf("chmod/chown/utimes ");
                         ev.fflags \*[Am]= ~NOTE_ATTRIB;
+                }
                 if (ev.fflags \*[Am] NOTE_LINK) {
                         printf("hardlinked ");
                         ev.fflags \*[Am]= ~NOTE_LINK;
+                }
                 if (ev.fflags \*[Am] NOTE_RENAME) {
                         printf("renamed ");
                         ev.fflags \*[Am]= ~NOTE_RENAME;
+                }
                 if (ev.fflags \*[Am] NOTE_REVOKE) {
                         printf("revoked ");
                         ev.fflags \*[Am]= ~NOTE_REVOKE;
+                }
                 printf("\\n");
                 if (ev.fflags)
                         warnx("unknown event 0x%x\\n", ev.fflags);
+        }
+}
 .Ed
 .Sh ERRORS
 The
 .Fn kqueue
 function fails if:
 .Bl -tag -width Er
 .It Bq Er EMFILE
 The per-process descriptor table is full.
 .It Bq Er ENFILE
 The system file table is full.
 .It Bq Er ENOMEM
 The kernel failed to allocate enough memory for the kernel queue.
 .El
 .Pp
 The
 .Fn kevent
 function fails if:
 .Bl -tag -width Er
 .It Bq Er EACCES
 The process does not have permission to register a filter.
 .It Bq Er EBADF
 The specified descriptor is invalid.
 .It Bq Er EFAULT
 There was an error reading or writing the
 .Va kevent
 structure.
 .It Bq Er EINTR
 A signal was delivered before the timeout expired and before any
 events were placed on the kqueue for return.
 .It Bq Er EINVAL
 The specified time limit or filter is invalid.
 .It Bq Er ENOENT
 The event could not be found to be modified or deleted.
 .It Bq Er ENOMEM
 No memory was available to register the event.
 .It Bq Er EOPNOTSUPP
 This type of file descriptor is not supported for
 .Fn kevent
 operations.
 .It Bq Er ESRCH
 The specified process to attach to does not exist.
 .El
 .Sh SEE ALSO
 .\" .Xr aio_error 2 ,
 .\" .Xr aio_read 2 ,
 .\" .Xr aio_return 2 ,
 .Xr ioctl 2 ,
 .Xr poll 2 ,
 .Xr read 2 ,
 .Xr select 2 ,
 .Xr sigaction 2 ,
 .Xr write 2 ,
 .Xr signal 3 ,
 .Xr kfilter_register 9 ,
 .Xr knote 9
 .Rs
 .%A Jonathan Lemon
 .%T "Kqueue: A Generic and Scalable Event Notification Facility"
 .%I USENIX Association
 .%B Proceedings of the FREENIX Track: 2001 USENIX Annual Technical Conference
 .%D June 25-30, 2001
 .%U http://www.usenix.org/event/usenix01/freenix01/full_papers/lemon/lemon.pdf
 .Re
 .Sh HISTORY
 The
 .Fn kqueue
 and
 .Fn kevent
 functions first appeared in
 .Fx 4.1 ,
 and then in
 .Nx 2.0 .
 The
 .Fn kqueue1
 function first appeared in
 .Nx 6.0 .

 @@ -1,1549 +1,1553 @@
-/*	$NetBSD: kern_event.c,v 1.80 2014/06/24 14:42:43 maxv Exp $	*/
+/*	$NetBSD: kern_event.c,v 1.80.2.1 2015/04/14 04:39:58 snj Exp $	*/
 /*-
  * Copyright (c) 2008, 2009 The NetBSD Foundation, Inc.
  * All rights reserved.
+ *
  * This code is derived from software contributed to The NetBSD Foundation
  * by Andrew Doran.
+ *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
+ *
  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  * POSSIBILITY OF SUCH DAMAGE.
  */
 /*-
  * Copyright (c) 1999,2000,2001 Jonathan Lemon <jlemon@FreeBSD.org>
  * All rights reserved.
+ *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
+ *
  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
+ *
  * FreeBSD: src/sys/kern/kern_event.c,v 1.27 2001/07/05 17:10:44 rwatson Exp
  */
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_event.c,v 1.80 2014/06/24 14:42:43 maxv Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_event.c,v 1.80.2.1 2015/04/14 04:39:58 snj Exp $");
 #include <sys/param.h>
 #include <sys/systm.h>
 #include <sys/kernel.h>
 #include <sys/proc.h>
 #include <sys/file.h>
 #include <sys/select.h>
 #include <sys/queue.h>
 #include <sys/event.h>
 #include <sys/eventvar.h>
 #include <sys/poll.h>
 #include <sys/kmem.h>
 #include <sys/stat.h>
 #include <sys/filedesc.h>
 #include <sys/syscallargs.h>
 #include <sys/kauth.h>
 #include <sys/conf.h>
 #include <sys/atomic.h>
 static int	kqueue_scan(file_t *, size_t, struct kevent *,
 			    const struct timespec *, register_t *,
 			    const struct kevent_ops *, struct kevent *,
 			    size_t);
 static int	kqueue_ioctl(file_t *, u_long, void *);
 static int	kqueue_fcntl(file_t *, u_int, void *);
 static int	kqueue_poll(file_t *, int);
 static int	kqueue_kqfilter(file_t *, struct knote *);
 static int	kqueue_stat(file_t *, struct stat *);
 static int	kqueue_close(file_t *);
 static int	kqueue_register(struct kqueue *, struct kevent *);
 static void	kqueue_doclose(struct kqueue *, struct klist *, int);
 static void	knote_detach(struct knote *, filedesc_t *fdp, bool);
 static void	knote_enqueue(struct knote *);
 static void	knote_activate(struct knote *);
 static void	filt_kqdetach(struct knote *);
 static int	filt_kqueue(struct knote *, long hint);
 static int	filt_procattach(struct knote *);
 static void	filt_procdetach(struct knote *);
 static int	filt_proc(struct knote *, long hint);
 static int	filt_fileattach(struct knote *);
 static void	filt_timerexpire(void *x);
 static int	filt_timerattach(struct knote *);
 static void	filt_timerdetach(struct knote *);
 static int	filt_timer(struct knote *, long hint);
 static const struct fileops kqueueops = {
 	.fo_read = (void *)enxio,
 	.fo_write = (void *)enxio,
 	.fo_ioctl = kqueue_ioctl,
 	.fo_fcntl = kqueue_fcntl,
 	.fo_poll = kqueue_poll,
 	.fo_stat = kqueue_stat,
 	.fo_close = kqueue_close,
 	.fo_kqfilter = kqueue_kqfilter,
 	.fo_restart = fnullop_restart,
 };
 static const struct filterops kqread_filtops =
 	{ 1, NULL, filt_kqdetach, filt_kqueue };
 static const struct filterops proc_filtops =
 	{ 0, filt_procattach, filt_procdetach, filt_proc };
 static const struct filterops file_filtops =
 	{ 1, filt_fileattach, NULL, NULL };
 static const struct filterops timer_filtops =
 	{ 0, filt_timerattach, filt_timerdetach, filt_timer };
 static u_int	kq_ncallouts = 0;
 static int	kq_calloutmax = (4 * 1024);
 #define	KN_HASHSIZE		64		/* XXX should be tunable */
 #define	KN_HASH(val, mask)	(((val) ^ (val >> 8)) & (mask))
 extern const struct filterops sig_filtops;
 /*
  * Table for for all system-defined filters.
  * These should be listed in the numeric order of the EVFILT_* defines.
  * If filtops is NULL, the filter isn't implemented in NetBSD.
  * End of list is when name is NULL.
+ *
  * Note that 'refcnt' is meaningless for built-in filters.
  */
 struct kfilter {
 	const char	*name;		/* name of filter */
 	uint32_t	filter;		/* id of filter */
 	unsigned	refcnt;		/* reference count */
 	const struct filterops *filtops;/* operations for filter */
 	size_t		namelen;	/* length of name string */
 };
 /* System defined filters */
 static struct kfilter sys_kfilters[] = {
 	{ "EVFILT_READ",	EVFILT_READ,	0, &file_filtops, 0 },
 	{ "EVFILT_WRITE",	EVFILT_WRITE,	0, &file_filtops, 0, },
 	{ "EVFILT_AIO",		EVFILT_AIO,	0, NULL, 0 },
 	{ "EVFILT_VNODE",	EVFILT_VNODE,	0, &file_filtops, 0 },
 	{ "EVFILT_PROC",	EVFILT_PROC,	0, &proc_filtops, 0 },
 	{ "EVFILT_SIGNAL",	EVFILT_SIGNAL,	0, &sig_filtops, 0 },
 	{ "EVFILT_TIMER",	EVFILT_TIMER,	0, &timer_filtops, 0 },
 	{ NULL,			0,		0, NULL, 0 },
 };
 /* User defined kfilters */
 static struct kfilter	*user_kfilters;		/* array */
 static int		user_kfilterc;		/* current offset */
 static int		user_kfiltermaxc;	/* max size so far */
 static size_t		user_kfiltersz;		/* size of allocated memory */
 /* Locks */
 static krwlock_t	kqueue_filter_lock;	/* lock on filter lists */
 static kmutex_t		kqueue_misc_lock;	/* miscellaneous */
 static kauth_listener_t	kqueue_listener;
 static int
 kqueue_listener_cb(kauth_cred_t cred, kauth_action_t action, void *cookie,
     void *arg0, void *arg1, void *arg2, void *arg3)
+{
 	struct proc *p;
 	int result;
 	result = KAUTH_RESULT_DEFER;
 	p = arg0;
 	if (action != KAUTH_PROCESS_KEVENT_FILTER)
 		return result;
 	if ((kauth_cred_getuid(p->p_cred) != kauth_cred_getuid(cred) ||
 	    ISSET(p->p_flag, PK_SUGID)))
 		return result;
 	result = KAUTH_RESULT_ALLOW;
 	return result;
+}
 /*
  * Initialize the kqueue subsystem.
  */
 void
 kqueue_init(void)
+{
 	rw_init(&kqueue_filter_lock);
 	mutex_init(&kqueue_misc_lock, MUTEX_DEFAULT, IPL_NONE);
 	kqueue_listener = kauth_listen_scope(KAUTH_SCOPE_PROCESS,
 	    kqueue_listener_cb, NULL);
+}
 /*
  * Find kfilter entry by name, or NULL if not found.
  */
 static struct kfilter *
 kfilter_byname_sys(const char *name)
+{
 	int i;
 	KASSERT(rw_lock_held(&kqueue_filter_lock));
 	for (i = 0; sys_kfilters[i].name != NULL; i++) {
 		if (strcmp(name, sys_kfilters[i].name) == 0)
 			return &sys_kfilters[i];
+	}
 	return NULL;
+}
 static struct kfilter *
 kfilter_byname_user(const char *name)
+{
 	int i;
 	KASSERT(rw_lock_held(&kqueue_filter_lock));
 	/* user filter slots have a NULL name if previously deregistered */
 	for (i = 0; i < user_kfilterc ; i++) {
 		if (user_kfilters[i].name != NULL &&
 		    strcmp(name, user_kfilters[i].name) == 0)
 			return &user_kfilters[i];
+	}
 	return NULL;
+}
 static struct kfilter *
 kfilter_byname(const char *name)
+{
 	struct kfilter *kfilter;
 	KASSERT(rw_lock_held(&kqueue_filter_lock));
 	if ((kfilter = kfilter_byname_sys(name)) != NULL)
 		return kfilter;
 	return kfilter_byname_user(name);
+}
 /*
  * Find kfilter entry by filter id, or NULL if not found.
  * Assumes entries are indexed in filter id order, for speed.
  */
 static struct kfilter *
 kfilter_byfilter(uint32_t filter)
+{
 	struct kfilter *kfilter;
 	KASSERT(rw_lock_held(&kqueue_filter_lock));
 	if (filter < EVFILT_SYSCOUNT)	/* it's a system filter */
 		kfilter = &sys_kfilters[filter];
 	else if (user_kfilters != NULL &&
 	    filter < EVFILT_SYSCOUNT + user_kfilterc)
 					/* it's a user filter */
 		kfilter = &user_kfilters[filter - EVFILT_SYSCOUNT];
 	else
 		return (NULL);		/* out of range */
 	KASSERT(kfilter->filter == filter);	/* sanity check! */
 	return (kfilter);
+}
 /*
  * Register a new kfilter. Stores the entry in user_kfilters.
  * Returns 0 if operation succeeded, or an appropriate errno(2) otherwise.
  * If retfilter != NULL, the new filterid is returned in it.
  */
 int
 kfilter_register(const char *name, const struct filterops *filtops,
 		 int *retfilter)
+{
 	struct kfilter *kfilter;
 	size_t len;
 	int i;
 	if (name == NULL || name[0] == '\0' || filtops == NULL)
 		return (EINVAL);	/* invalid args */
 	rw_enter(&kqueue_filter_lock, RW_WRITER);
 	if (kfilter_byname(name) != NULL) {
 		rw_exit(&kqueue_filter_lock);
 		return (EEXIST);	/* already exists */
+	}
 	if (user_kfilterc > 0xffffffff - EVFILT_SYSCOUNT) {
 		rw_exit(&kqueue_filter_lock);
 		return (EINVAL);	/* too many */
+	}
 	for (i = 0; i < user_kfilterc; i++) {
 		kfilter = &user_kfilters[i];
 		if (kfilter->name == NULL) {
 			/* Previously deregistered slot.  Reuse. */
 			goto reuse;
+		}
+	}
 	/* check if need to grow user_kfilters */
 	if (user_kfilterc + 1 > user_kfiltermaxc) {
 		/* Grow in KFILTER_EXTENT chunks. */
 		user_kfiltermaxc += KFILTER_EXTENT;
 		len = user_kfiltermaxc * sizeof(*kfilter);
 		kfilter = kmem_alloc(len, KM_SLEEP);
 		memset((char *)kfilter + user_kfiltersz, 0, len - user_kfiltersz);
 		if (user_kfilters != NULL) {
 			memcpy(kfilter, user_kfilters, user_kfiltersz);
 			kmem_free(user_kfilters, user_kfiltersz);
+		}
 		user_kfiltersz = len;
 		user_kfilters = kfilter;
+	}
 	/* Adding new slot */
 	kfilter = &user_kfilters[user_kfilterc++];
 reuse:
 	kfilter->namelen = strlen(name) + 1;
 	kfilter->name = kmem_alloc(kfilter->namelen, KM_SLEEP);
 	memcpy(__UNCONST(kfilter->name), name, kfilter->namelen);
 	kfilter->filter = (kfilter - user_kfilters) + EVFILT_SYSCOUNT;
 	kfilter->filtops = kmem_alloc(sizeof(*filtops), KM_SLEEP);
 	memcpy(__UNCONST(kfilter->filtops), filtops, sizeof(*filtops));
 	if (retfilter != NULL)
 		*retfilter = kfilter->filter;
 	rw_exit(&kqueue_filter_lock);
 	return (0);
+}
 /*
  * Unregister a kfilter previously registered with kfilter_register.
  * This retains the filter id, but clears the name and frees filtops (filter
  * operations), so that the number isn't reused during a boot.
  * Returns 0 if operation succeeded, or an appropriate errno(2) otherwise.
  */
 int
 kfilter_unregister(const char *name)
+{
 	struct kfilter *kfilter;
 	if (name == NULL || name[0] == '\0')
 		return (EINVAL);	/* invalid name */
 	rw_enter(&kqueue_filter_lock, RW_WRITER);
 	if (kfilter_byname_sys(name) != NULL) {
 		rw_exit(&kqueue_filter_lock);
 		return (EINVAL);	/* can't detach system filters */
+	}
 	kfilter = kfilter_byname_user(name);
 	if (kfilter == NULL) {
 		rw_exit(&kqueue_filter_lock);
 		return (ENOENT);
+	}
 	if (kfilter->refcnt != 0) {
 		rw_exit(&kqueue_filter_lock);
 		return (EBUSY);
+	}
 	/* Cast away const (but we know it's safe. */
 	kmem_free(__UNCONST(kfilter->name), kfilter->namelen);
 	kfilter->name = NULL;	/* mark as `not implemented' */
 	if (kfilter->filtops != NULL) {
 		/* Cast away const (but we know it's safe. */
 		kmem_free(__UNCONST(kfilter->filtops),
 		    sizeof(*kfilter->filtops));
 		kfilter->filtops = NULL; /* mark as `not implemented' */
+	}
 	rw_exit(&kqueue_filter_lock);
 	return (0);
+}
 /*
  * Filter attach method for EVFILT_READ and EVFILT_WRITE on normal file
  * descriptors. Calls fileops kqfilter method for given file descriptor.
  */
 static int
 filt_fileattach(struct knote *kn)
+{
 	file_t *fp;
 	fp = kn->kn_obj;
 	return (*fp->f_ops->fo_kqfilter)(fp, kn);
+}
 /*
  * Filter detach method for EVFILT_READ on kqueue descriptor.
  */
 static void
 filt_kqdetach(struct knote *kn)
+{
 	struct kqueue *kq;
 	kq = ((file_t *)kn->kn_obj)->f_data;
 	mutex_spin_enter(&kq->kq_lock);
 	SLIST_REMOVE(&kq->kq_sel.sel_klist, kn, knote, kn_selnext);
 	mutex_spin_exit(&kq->kq_lock);
+}
 /*
  * Filter event method for EVFILT_READ on kqueue descriptor.
  */
 /*ARGSUSED*/
 static int
 filt_kqueue(struct knote *kn, long hint)
+{
 	struct kqueue *kq;
 	int rv;
 	kq = ((file_t *)kn->kn_obj)->f_data;
 	if (hint != NOTE_SUBMIT)
 		mutex_spin_enter(&kq->kq_lock);
 	kn->kn_data = kq->kq_count;
 	rv = (kn->kn_data > 0);
 	if (hint != NOTE_SUBMIT)
 		mutex_spin_exit(&kq->kq_lock);
 	return rv;
+}
 /*
  * Filter attach method for EVFILT_PROC.
  */
 static int
 filt_procattach(struct knote *kn)
+{
 	struct proc *p;
 	struct lwp *curl;
 	curl = curlwp;
 	mutex_enter(proc_lock);
 	if (kn->kn_flags & EV_FLAG1) {
 		/*
 		 * NOTE_TRACK attaches to the child process too early
 		 * for proc_find, so do a raw look up and check the state
 		 * explicitly.
 		 */
 		p = proc_find_raw(kn->kn_id);
 		if (p != NULL && p->p_stat != SIDL)
 			p = NULL;
 	} else {
 		p = proc_find(kn->kn_id);
+	}
 	if (p == NULL) {
 		mutex_exit(proc_lock);
 		return ESRCH;
+	}
 	/*
 	 * Fail if it's not owned by you, or the last exec gave us
 	 * setuid/setgid privs (unless you're root).
 	 */
 	mutex_enter(p->p_lock);
 	mutex_exit(proc_lock);
 	if (kauth_authorize_process(curl->l_cred, KAUTH_PROCESS_KEVENT_FILTER,
 	    p, NULL, NULL, NULL) != 0) {
 	    	mutex_exit(p->p_lock);
 		return EACCES;
+	}
 	kn->kn_obj = p;
 	kn->kn_flags |= EV_CLEAR;	/* automatically set */
 	/*
 	 * internal flag indicating registration done by kernel
 	 */
 	if (kn->kn_flags & EV_FLAG1) {
 		kn->kn_data = kn->kn_sdata;	/* ppid */
 		kn->kn_fflags = NOTE_CHILD;
 		kn->kn_flags &= ~EV_FLAG1;
+	}
 	SLIST_INSERT_HEAD(&p->p_klist, kn, kn_selnext);
     	mutex_exit(p->p_lock);
 	return 0;
+}
 /*
  * Filter detach method for EVFILT_PROC.
+ *
  * 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 might not exist any more.
  */
 static void
 filt_procdetach(struct knote *kn)
+{
 	struct proc *p;
 	if (kn->kn_status & KN_DETACHED)
 		return;
 	p = kn->kn_obj;
 	mutex_enter(p->p_lock);
 	SLIST_REMOVE(&p->p_klist, kn, knote, kn_selnext);
 	mutex_exit(p->p_lock);
+}
 /*
  * Filter event method for EVFILT_PROC.
  */
 static int
 filt_proc(struct knote *kn, long hint)
+{
 	u_int event, fflag;
 	struct kevent kev;
 	struct kqueue *kq;
 	int error;
 	event = (u_int)hint & NOTE_PCTRLMASK;
 	kq = kn->kn_kq;
 	fflag = 0;
 	/* If the user is interested in this event, record it. */
 	if (kn->kn_sfflags & event)
 		fflag |= event;
 	if (event == NOTE_EXIT) {
 		struct proc *p = kn->kn_obj;
 		if (p != NULL)
 			kn->kn_data = p->p_xstat;
 		/*
 		 * Process is gone, so flag the event as finished.
+		 *
 		 * Detach the knote from watched process and mark
 		 * it as such. We can't leave this to kqueue_scan(),
 		 * since the process might not exist by then. And we
 		 * have to do this now, since psignal KNOTE() is called
 		 * also for zombies and we might end up reading freed
 		 * memory if the kevent would already be picked up
 		 * and knote g/c'ed.
 		 */
 		filt_procdetach(kn);
 		mutex_spin_enter(&kq->kq_lock);
 		kn->kn_status |= KN_DETACHED;
 		/* Mark as ONESHOT, so that the knote it g/c'ed when read */
 		kn->kn_flags |= (EV_EOF | EV_ONESHOT);
 		kn->kn_fflags |= fflag;
 		mutex_spin_exit(&kq->kq_lock);
 		return 1;
+	}
 	mutex_spin_enter(&kq->kq_lock);
 	if ((event == NOTE_FORK) && (kn->kn_sfflags & NOTE_TRACK)) {
 		/*
 		 * 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.  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 */
 		mutex_spin_exit(&kq->kq_lock);
 		error = kqueue_register(kq, &kev);
 		mutex_spin_enter(&kq->kq_lock);
 		if (error != 0)
 			kn->kn_fflags |= NOTE_TRACKERR;
+	}
 	kn->kn_fflags |= fflag;
 	fflag = kn->kn_fflags;
 	mutex_spin_exit(&kq->kq_lock);
 	return fflag != 0;
+}
 static void
 filt_timerexpire(void *knx)
+{
 	struct knote *kn = knx;
 	int tticks;
 	mutex_enter(&kqueue_misc_lock);
 	kn->kn_data++;
 	knote_activate(kn);
 	if ((kn->kn_flags & EV_ONESHOT) == 0) {
 		tticks = mstohz(kn->kn_sdata);
 		if (tticks <= 0)
 			tticks = 1;
 		callout_schedule((callout_t *)kn->kn_hook, tticks);
+	}
 	mutex_exit(&kqueue_misc_lock);
+}
 /*
  * data contains amount of time to sleep, in milliseconds
  */
 static int
 filt_timerattach(struct knote *kn)
+{
 	callout_t *calloutp;
 	struct kqueue *kq;
 	int tticks;
 	tticks = mstohz(kn->kn_sdata);
 	/* if the supplied value is under our resolution, use 1 tick */
 	if (tticks == 0) {
 		if (kn->kn_sdata == 0)
 			return EINVAL;
 		tticks = 1;
+	}
 	if (atomic_inc_uint_nv(&kq_ncallouts) >= kq_calloutmax ||
 	    (calloutp = kmem_alloc(sizeof(*calloutp), KM_NOSLEEP)) == NULL) {
 		atomic_dec_uint(&kq_ncallouts);
 		return ENOMEM;
+	}
 	callout_init(calloutp, CALLOUT_MPSAFE);
 	kq = kn->kn_kq;
 	mutex_spin_enter(&kq->kq_lock);
 	kn->kn_flags |= EV_CLEAR;		/* automatically set */
 	kn->kn_hook = calloutp;
 	mutex_spin_exit(&kq->kq_lock);
 	callout_reset(calloutp, tticks, filt_timerexpire, kn);
 	return (0);
+}
 static void
 filt_timerdetach(struct knote *kn)
+{
 	callout_t *calloutp;
 	calloutp = (callout_t *)kn->kn_hook;
 	callout_halt(calloutp, NULL);
 	callout_destroy(calloutp);
 	kmem_free(calloutp, sizeof(*calloutp));
 	atomic_dec_uint(&kq_ncallouts);
+}
 static int
 filt_timer(struct knote *kn, long hint)
+{
 	int rv;
 	mutex_enter(&kqueue_misc_lock);
 	rv = (kn->kn_data != 0);
 	mutex_exit(&kqueue_misc_lock);
 	return rv;
+}
 /*
  * filt_seltrue:
+ *
  *	This filter "event" routine simulates seltrue().
  */
 int
 filt_seltrue(struct knote *kn, long hint)
+{
 	/*
 	 * We don't know how much data can be read/written,
 	 * but we know that it *can* be.  This is about as
 	 * good as select/poll does as well.
 	 */
 	kn->kn_data = 0;
 	return (1);
+}
 /*
  * This provides full kqfilter entry for device switch tables, which
  * has same effect as filter using filt_seltrue() as filter method.
  */
 static void
 filt_seltruedetach(struct knote *kn)
+{
 	/* Nothing to do */
+}
 const struct filterops seltrue_filtops =
 	{ 1, NULL, filt_seltruedetach, filt_seltrue };
 int
 seltrue_kqfilter(dev_t dev, struct knote *kn)
+{
 	switch (kn->kn_filter) {
 	case EVFILT_READ:
 	case EVFILT_WRITE:
 		kn->kn_fop = &seltrue_filtops;
 		break;
 	default:
 		return (EINVAL);
+	}
 	/* Nothing more to do */
 	return (0);
+}
 /*
  * kqueue(2) system call.
  */
 static int
 kqueue1(struct lwp *l, int flags, register_t *retval)
+{
 	struct kqueue *kq;
 	file_t *fp;
 	int fd, error;
 	if ((error = fd_allocfile(&fp, &fd)) != 0)
 		return error;
 	fp->f_flag = FREAD | FWRITE | (flags & (FNONBLOCK|FNOSIGPIPE));
 	fp->f_type = DTYPE_KQUEUE;
 	fp->f_ops = &kqueueops;
 	kq = kmem_zalloc(sizeof(*kq), KM_SLEEP);
 	mutex_init(&kq->kq_lock, MUTEX_DEFAULT, IPL_SCHED);
 	cv_init(&kq->kq_cv, "kqueue");
 	selinit(&kq->kq_sel);
 	TAILQ_INIT(&kq->kq_head);
 	fp->f_data = kq;
 	*retval = fd;
 	kq->kq_fdp = curlwp->l_fd;
 	fd_set_exclose(l, fd, (flags & O_CLOEXEC) != 0);
 	fd_affix(curproc, fp, fd);
 	return error;
+}
 /*
  * kqueue(2) system call.
  */
 int
 sys_kqueue(struct lwp *l, const void *v, register_t *retval)
+{
 	return kqueue1(l, 0, retval);
+}
 int
 sys_kqueue1(struct lwp *l, const struct sys_kqueue1_args *uap,
     register_t *retval)
+{
 	/* {
 		syscallarg(int) flags;
 	} */
 	return kqueue1(l, SCARG(uap, flags), retval);
+}
 /*
  * kevent(2) system call.
  */
 int
 kevent_fetch_changes(void *private, const struct kevent *changelist,
     struct kevent *changes, size_t index, int n)
+{
 	return copyin(changelist + index, changes, n * sizeof(*changes));
+}
 int
 kevent_put_events(void *private, struct kevent *events,
     struct kevent *eventlist, size_t index, int n)
+{
 	return copyout(events, eventlist + index, n * sizeof(*events));
+}
 static const struct kevent_ops kevent_native_ops = {
 	.keo_private = NULL,
 	.keo_fetch_timeout = copyin,
 	.keo_fetch_changes = kevent_fetch_changes,
 	.keo_put_events = kevent_put_events,
 };
 int
 sys___kevent50(struct lwp *l, const struct sys___kevent50_args *uap,
     register_t *retval)
+{
 	/* {
 		syscallarg(int) fd;
 		syscallarg(const struct kevent *) changelist;
 		syscallarg(size_t) nchanges;
 		syscallarg(struct kevent *) eventlist;
 		syscallarg(size_t) nevents;
 		syscallarg(const struct timespec *) timeout;
 	} */
 	return kevent1(retval, SCARG(uap, fd), SCARG(uap, changelist),
 	    SCARG(uap, nchanges), SCARG(uap, eventlist), SCARG(uap, nevents),
 	    SCARG(uap, timeout), &kevent_native_ops);
+}
 int
 kevent1(register_t *retval, int fd,
 	const struct kevent *changelist, size_t nchanges,
 	struct kevent *eventlist, size_t nevents,
 	const struct timespec *timeout,
 	const struct kevent_ops *keops)
+{
 	struct kevent *kevp;
 	struct kqueue *kq;
 	struct timespec	ts;
 	size_t i, n, ichange;
 	int nerrors, error;
 	struct kevent kevbuf[KQ_NEVENTS];	/* approx 300 bytes on 64-bit */
 	file_t *fp;
 	/* check that we're dealing with a kq */
 	fp = fd_getfile(fd);
 	if (fp == NULL)
 		return (EBADF);
 	if (fp->f_type != DTYPE_KQUEUE) {
 		fd_putfile(fd);
 		return (EBADF);
+	}
 	if (timeout != NULL) {
 		error = (*keops->keo_fetch_timeout)(timeout, &ts, sizeof(ts));
 		if (error)
 			goto done;
 		timeout = &ts;
+	}
 	kq = (struct kqueue *)fp->f_data;
 	nerrors = 0;
 	ichange = 0;
 	/* traverse list of events to register */
 	while (nchanges > 0) {
 		n = MIN(nchanges, __arraycount(kevbuf));
 		error = (*keops->keo_fetch_changes)(keops->keo_private,
 		    changelist, kevbuf, ichange, n);
 		if (error)
 			goto done;
 		for (i = 0; i < n; i++) {
 			kevp = &kevbuf[i];
 			kevp->flags &= ~EV_SYSFLAGS;
 			/* register each knote */
 			error = kqueue_register(kq, kevp);
 			if (error) {
 				if (nevents != 0) {
 					kevp->flags = EV_ERROR;
 					kevp->data = error;
 					error = (*keops->keo_put_events)
 					    (keops->keo_private, kevp,
 					    eventlist, nerrors, 1);
 					if (error)
 						goto done;
 					nevents--;
 					nerrors++;
 				} else {
 					goto done;
+				}
+			}
+		}
 		nchanges -= n;	/* update the results */
 		ichange += n;
+	}
 	if (nerrors) {
 		*retval = nerrors;
 		error = 0;
 		goto done;
+	}
 	/* actually scan through the events */
 	error = kqueue_scan(fp, nevents, eventlist, timeout, retval, keops,
 	    kevbuf, __arraycount(kevbuf));
  done:
 	fd_putfile(fd);
 	return (error);
+}
 /*
  * Register a given kevent kev onto the kqueue
  */
 static int
 kqueue_register(struct kqueue *kq, struct kevent *kev)
+{
 	struct kfilter *kfilter;
 	filedesc_t *fdp;
 	file_t *fp;
 	fdfile_t *ff;
 	struct knote *kn, *newkn;
 	struct klist *list;
 	int error, fd, rv;
 	fdp = kq->kq_fdp;
 	fp = NULL;
 	kn = NULL;
 	error = 0;
 	fd = 0;
 	newkn = kmem_zalloc(sizeof(*newkn), KM_SLEEP);
 	rw_enter(&kqueue_filter_lock, RW_READER);
 	kfilter = kfilter_byfilter(kev->filter);
 	if (kfilter == NULL || kfilter->filtops == NULL) {
 		/* filter not found nor implemented */
 		rw_exit(&kqueue_filter_lock);
 		kmem_free(newkn, sizeof(*newkn));
 		return (EINVAL);
+	}
 	/* search if knote already exists */
 	if (kfilter->filtops->f_isfd) {
 		/* monitoring a file descriptor */
 		fd = kev->ident;
 		if ((fp = fd_getfile(fd)) == NULL) {
 			rw_exit(&kqueue_filter_lock);
 			kmem_free(newkn, sizeof(*newkn));
 			return EBADF;
+		}
 		mutex_enter(&fdp->fd_lock);
 		ff = fdp->fd_dt->dt_ff[fd];
 		if (fd <= fdp->fd_lastkqfile) {
 			SLIST_FOREACH(kn, &ff->ff_knlist, kn_link) {
 				if (kq == kn->kn_kq &&
 				    kev->filter == kn->kn_filter)
 					break;
+			}
+		}
 	} else {
 		/*
 		 * not monitoring a file descriptor, so
 		 * lookup knotes in internal hash table
 		 */
 		mutex_enter(&fdp->fd_lock);
 		if (fdp->fd_knhashmask != 0) {
 			list = &fdp->fd_knhash[
 			    KN_HASH((u_long)kev->ident, fdp->fd_knhashmask)];
 			SLIST_FOREACH(kn, list, kn_link) {
 				if (kev->ident == kn->kn_id &&
 				    kq == kn->kn_kq &&
 				    kev->filter == kn->kn_filter)
 					break;
+			}
+		}
+	}
 	/*
 	 * kn now contains the matching knote, or NULL if no match
 	 */
 	if (kev->flags & EV_ADD) {
 		if (kn == NULL) {
 			/* create new knote */
 			kn = newkn;
 			newkn = NULL;
 			kn->kn_obj = fp;
 			kn->kn_id = kev->ident;
 			kn->kn_kq = kq;
 			kn->kn_fop = kfilter->filtops;
 			kn->kn_kfilter = kfilter;
 			kn->kn_sfflags = kev->fflags;
 			kn->kn_sdata = kev->data;
 			kev->fflags = 0;
 			kev->data = 0;
 			kn->kn_kevent = *kev;
 			/*
 			 * apply reference count to knote structure, and
 			 * do not release it at the end of this routine.
 			 */
 			fp = NULL;
 			if (!kn->kn_fop->f_isfd) {
 				/*
 				 * If knote is not on an fd, store on
 				 * internal hash table.
 				 */
 				if (fdp->fd_knhashmask == 0) {
 					/* XXXAD can block with fd_lock held */
 					fdp->fd_knhash = hashinit(KN_HASHSIZE,
 					    HASH_LIST, true,
 					    &fdp->fd_knhashmask);
+				}
 				list = &fdp->fd_knhash[KN_HASH(kn->kn_id,
 				    fdp->fd_knhashmask)];
 			} else {
 				/* Otherwise, knote is on an fd. */
 				list = (struct klist *)
 				    &fdp->fd_dt->dt_ff[kn->kn_id]->ff_knlist;
 				if ((int)kn->kn_id > fdp->fd_lastkqfile)
 					fdp->fd_lastkqfile = kn->kn_id;
+			}
 			SLIST_INSERT_HEAD(list, kn, kn_link);
 			KERNEL_LOCK(1, NULL);		/* XXXSMP */
 			error = (*kfilter->filtops->f_attach)(kn);
 			KERNEL_UNLOCK_ONE(NULL);	/* XXXSMP */
 			if (error != 0) {
 #ifdef DIAGNOSTIC
 				printf("%s: event not supported for file type"
 				    " %d\n", __func__, fp ? fp->f_type : -1);
 #endif
 				/* knote_detach() drops fdp->fd_lock */
 				knote_detach(kn, fdp, false);
 				goto done;
+			}
 			atomic_inc_uint(&kfilter->refcnt);
 		} else {
 			/*
 			 * The user may change some filter values after the
 			 * initial EV_ADD, but doing so will not reset any
 			 * filter which have already been triggered.
 			 */
 			kn->kn_sfflags = kev->fflags;
 			kn->kn_sdata = kev->data;
 			kn->kn_kevent.udata = kev->udata;
+		}
 		/*
 		 * We can get here if we are trying to attach
 		 * an event to a file descriptor that does not
 		 * support events, and the attach routine is
 		 * broken and does not return an error.
 		 */
 		KASSERT(kn->kn_fop->f_event != NULL);
 		KERNEL_LOCK(1, NULL);			/* XXXSMP */
 		rv = (*kn->kn_fop->f_event)(kn, 0);
 		KERNEL_UNLOCK_ONE(NULL);		/* XXXSMP */
 		if (rv)
 			knote_activate(kn);
 	} else {
 		if (kn == NULL) {
 			error = ENOENT;
 		 	mutex_exit(&fdp->fd_lock);
 			goto done;
+		}
 		if (kev->flags & EV_DELETE) {
 			/* knote_detach() drops fdp->fd_lock */
 			knote_detach(kn, fdp, true);
 			goto done;
+		}
+	}
 	/* disable knote */
 	if ((kev->flags & EV_DISABLE)) {
 		mutex_spin_enter(&kq->kq_lock);
 		if ((kn->kn_status & KN_DISABLED) == 0)
 			kn->kn_status |= KN_DISABLED;
 		mutex_spin_exit(&kq->kq_lock);
+	}
 	/* enable knote */
 	if ((kev->flags & EV_ENABLE)) {
 		knote_enqueue(kn);
+	}
 	mutex_exit(&fdp->fd_lock);
  done:
 	rw_exit(&kqueue_filter_lock);
 	if (newkn != NULL)
 		kmem_free(newkn, sizeof(*newkn));
 	if (fp != NULL)
 		fd_putfile(fd);
 	return (error);
+}
 #if defined(DEBUG)
 static void
 kq_check(struct kqueue *kq)
+{
 	const struct knote *kn;
 	int count;
 	int nmarker;
 	KASSERT(mutex_owned(&kq->kq_lock));
 	KASSERT(kq->kq_count >= 0);
 	count = 0;
 	nmarker = 0;
 	TAILQ_FOREACH(kn, &kq->kq_head, kn_tqe) {
 		if ((kn->kn_status & (KN_MARKER | KN_QUEUED)) == 0) {
 			panic("%s: kq=%p kn=%p inconsist 1", __func__, kq, kn);
+		}
 		if ((kn->kn_status & KN_MARKER) == 0) {
 			if (kn->kn_kq != kq) {
 				panic("%s: kq=%p kn=%p inconsist 2",
 				    __func__, kq, kn);
+			}
 			if ((kn->kn_status & KN_ACTIVE) == 0) {
 				panic("%s: kq=%p kn=%p: not active",
 				    __func__, kq, kn);
+			}
 			count++;
 			if (count > kq->kq_count) {
 				goto bad;
+			}
 		} else {
 			nmarker++;
 #if 0
 			if (nmarker > 10000) {
 				panic("%s: kq=%p too many markers: %d != %d, "
 				    "nmarker=%d",
 				    __func__, kq, kq->kq_count, count, nmarker);
+			}
 #endif
+		}
+	}
 	if (kq->kq_count != count) {
 bad:
 		panic("%s: kq=%p inconsist 3: %d != %d, nmarker=%d",
 		    __func__, kq, kq->kq_count, count, nmarker);
+	}
+}
 #else /* defined(DEBUG) */
 #define	kq_check(a)	/* nothing */
 #endif /* defined(DEBUG) */
 /*
  * Scan through the list of events on fp (for a maximum of maxevents),
  * returning the results in to ulistp. Timeout is determined by tsp; if
  * NULL, wait indefinitely, if 0 valued, perform a poll, otherwise wait
  * as appropriate.
  */
 static int
 kqueue_scan(file_t *fp, size_t maxevents, struct kevent *ulistp,
 	    const struct timespec *tsp, register_t *retval,
 	    const struct kevent_ops *keops, struct kevent *kevbuf,
 	    size_t kevcnt)
+{
 	struct kqueue	*kq;
 	struct kevent	*kevp;
 	struct timespec	ats, sleepts;
 	struct knote	*kn, *marker;
 	size_t		count, nkev, nevents;
 	int		timeout, error, rv;
 	filedesc_t	*fdp;
 	fdp = curlwp->l_fd;
 	kq = fp->f_data;
 	count = maxevents;
 	nkev = nevents = error = 0;
 	if (count == 0) {
 		*retval = 0;
 		return 0;
+	}
 	if (tsp) {				/* timeout supplied */
 		ats = *tsp;
 		if (inittimeleft(&ats, &sleepts) == -1) {
 			*retval = maxevents;
 			return EINVAL;
+		}
 		timeout = tstohz(&ats);
 		if (timeout <= 0)
 			timeout = -1;           /* do poll */
 	} else {
 		/* no timeout, wait forever */
 		timeout = 0;
+	}
 	marker = kmem_zalloc(sizeof(*marker), KM_SLEEP);
 	marker->kn_status = KN_MARKER;
 	mutex_spin_enter(&kq->kq_lock);
  retry:
 	kevp = kevbuf;
 	if (kq->kq_count == 0) {
 		if (timeout >= 0) {
 			error = cv_timedwait_sig(&kq->kq_cv,
 			    &kq->kq_lock, timeout);
 			if (error == 0) {
 				 if (tsp == NULL || (timeout =
 				     gettimeleft(&ats, &sleepts)) > 0)
 					goto retry;
 			} else {
 				/* don't restart after signals... */
 				if (error == ERESTART)
 					error = EINTR;
 				if (error == EWOULDBLOCK)
 					error = 0;
+			}
+		}
 	} else {
 		/* mark end of knote list */
 		TAILQ_INSERT_TAIL(&kq->kq_head, marker, kn_tqe);
 		while (count != 0) {
 			kn = TAILQ_FIRST(&kq->kq_head);	/* get next knote */
 			while ((kn->kn_status & KN_MARKER) != 0) {
 				if (kn == marker) {
 					/* it's our marker, stop */
 					TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe);
 					if (count < maxevents || (tsp != NULL &&
 					    (timeout = gettimeleft(&ats,
 					    &sleepts)) <= 0))
 						goto done;
 					goto retry;
+				}
 				/* someone else's marker. */
 				kn = TAILQ_NEXT(kn, kn_tqe);
+			}
 			kq_check(kq);
 			TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe);
 			kq->kq_count--;
 			kn->kn_status &= ~KN_QUEUED;
 			kq_check(kq);
 			if (kn->kn_status & KN_DISABLED) {
 				/* don't want disabled events */
 				continue;
+			}
 			if ((kn->kn_flags & EV_ONESHOT) == 0) {
 				mutex_spin_exit(&kq->kq_lock);
 				KERNEL_LOCK(1, NULL);		/* XXXSMP */
 				rv = (*kn->kn_fop->f_event)(kn, 0);
 				KERNEL_UNLOCK_ONE(NULL);	/* XXXSMP */
 				mutex_spin_enter(&kq->kq_lock);
 				/* Re-poll if note was re-enqueued. */
 				if ((kn->kn_status & KN_QUEUED) != 0)
 					continue;
 				if (rv == 0) {
 					/*
 					 * non-ONESHOT event that hasn't
 					 * triggered again, so de-queue.
 					 */
 					kn->kn_status &= ~KN_ACTIVE;
 					continue;
+				}
+			}
 			/* XXXAD should be got from f_event if !oneshot. */
 			*kevp++ = kn->kn_kevent;
 			nkev++;
 			if (kn->kn_flags & EV_ONESHOT) {
 				/* delete ONESHOT events after retrieval */
 				mutex_spin_exit(&kq->kq_lock);
 				mutex_enter(&fdp->fd_lock);
 				knote_detach(kn, fdp, true);
 				mutex_spin_enter(&kq->kq_lock);
 			} else if (kn->kn_flags & EV_CLEAR) {
 				/* clear state after retrieval */
 				kn->kn_data = 0;
 				kn->kn_fflags = 0;
 				kn->kn_status &= ~KN_ACTIVE;
 			} else {
 				/* add event back on list */
 				kq_check(kq);
 				TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe);
 				kq->kq_count++;
 				kn->kn_status |= KN_QUEUED;
 				kq_check(kq);
+			}
 			if (nkev == kevcnt) {
 				/* do copyouts in kevcnt chunks */
 				mutex_spin_exit(&kq->kq_lock);
 				error = (*keops->keo_put_events)
 				    (keops->keo_private,
 				    kevbuf, ulistp, nevents, nkev);
 				mutex_spin_enter(&kq->kq_lock);
 				nevents += nkev;
 				nkev = 0;
 				kevp = kevbuf;
+			}
 			count--;
 			if (error != 0 || count == 0) {
 				/* remove marker */
 				TAILQ_REMOVE(&kq->kq_head, marker, kn_tqe);
 				break;
+			}
+		}
+	}
  done:
  	mutex_spin_exit(&kq->kq_lock);
 	if (marker != NULL)
 		kmem_free(marker, sizeof(*marker));
 	if (nkev != 0) {
 		/* copyout remaining events */
 		error = (*keops->keo_put_events)(keops->keo_private,
 		    kevbuf, ulistp, nevents, nkev);
+	}
 	*retval = maxevents - count;
 	return error;
+}
 /*
  * fileops ioctl method for a kqueue descriptor.
+ *
  * Two ioctls are currently supported. They both use struct kfilter_mapping:
  *	KFILTER_BYNAME		find name for filter, and return result in
  *				name, which is of size len.
  *	KFILTER_BYFILTER	find filter for name. len is ignored.
  */
 /*ARGSUSED*/
 static int
 kqueue_ioctl(file_t *fp, u_long com, void *data)
+{
 	struct kfilter_mapping	*km;
 	const struct kfilter	*kfilter;
 	char			*name;
 	int			error;
 	km = data;
 	error = 0;
 	name = kmem_alloc(KFILTER_MAXNAME, KM_SLEEP);
 	switch (com) {
 	case KFILTER_BYFILTER:	/* convert filter -> name */
 		rw_enter(&kqueue_filter_lock, RW_READER);
 		kfilter = kfilter_byfilter(km->filter);
 		if (kfilter != NULL) {
 			strlcpy(name, kfilter->name, KFILTER_MAXNAME);
 			rw_exit(&kqueue_filter_lock);
 			error = copyoutstr(name, km->name, km->len, NULL);
 		} else {
 			rw_exit(&kqueue_filter_lock);
 			error = ENOENT;
+		}
 		break;
 	case KFILTER_BYNAME:	/* convert name -> filter */
 		error = copyinstr(km->name, name, KFILTER_MAXNAME, NULL);
 		if (error) {
 			break;
+		}
 		rw_enter(&kqueue_filter_lock, RW_READER);
 		kfilter = kfilter_byname(name);
 		if (kfilter != NULL)
 			km->filter = kfilter->filter;
 		else
 			error = ENOENT;
 		rw_exit(&kqueue_filter_lock);
 		break;
 	default:
 		error = ENOTTY;
 		break;
+	}
 	kmem_free(name, KFILTER_MAXNAME);
 	return (error);
+}
 /*
  * fileops fcntl method for a kqueue descriptor.
  */
 static int
 kqueue_fcntl(file_t *fp, u_int com, void *data)
+{
 	return (ENOTTY);
+}
 /*
  * fileops poll method for a kqueue descriptor.
  * Determine if kqueue has events pending.
  */
 static int
 kqueue_poll(file_t *fp, int events)
+{
 	struct kqueue	*kq;
 	int		revents;
 	kq = fp->f_data;
 	revents = 0;
 	if (events & (POLLIN | POLLRDNORM)) {
 		mutex_spin_enter(&kq->kq_lock);
 		if (kq->kq_count != 0) {
 			revents |= events & (POLLIN | POLLRDNORM);
 		} else {
 			selrecord(curlwp, &kq->kq_sel);
+		}
 		kq_check(kq);
 		mutex_spin_exit(&kq->kq_lock);
+	}
 	return revents;
+}
 /*
  * fileops stat method for a kqueue descriptor.
  * Returns dummy info, with st_size being number of events pending.
  */
 static int
 kqueue_stat(file_t *fp, struct stat *st)
+{
 	struct kqueue *kq;
 	kq = fp->f_data;
 	memset(st, 0, sizeof(*st));
 	st->st_size = kq->kq_count;
 	st->st_blksize = sizeof(struct kevent);
 	st->st_mode = S_IFIFO;
 	return 0;
+}
 static void
 kqueue_doclose(struct kqueue *kq, struct klist *list, int fd)
+{
 	struct knote *kn;
 	filedesc_t *fdp;
 	fdp = kq->kq_fdp;
 	KASSERT(mutex_owned(&fdp->fd_lock));
 	for (kn = SLIST_FIRST(list); kn != NULL;) {
 		if (kq != kn->kn_kq) {
 			kn = SLIST_NEXT(kn, kn_link);
 			continue;
+		}
 		knote_detach(kn, fdp, true);
 		mutex_enter(&fdp->fd_lock);
 		kn = SLIST_FIRST(list);
+	}
+}
 /*
  * fileops close method for a kqueue descriptor.
  */
 static int
 kqueue_close(file_t *fp)
+{
 	struct kqueue *kq;
 	filedesc_t *fdp;
 	fdfile_t *ff;
 	int i;
 	kq = fp->f_data;
 	fp->f_data = NULL;
 	fp->f_type = 0;
 	fdp = curlwp->l_fd;
 	mutex_enter(&fdp->fd_lock);
 	for (i = 0; i <= fdp->fd_lastkqfile; i++) {
 		if ((ff = fdp->fd_dt->dt_ff[i]) == NULL)
 			continue;
 		kqueue_doclose(kq, (struct klist *)&ff->ff_knlist, i);
+	}
 	if (fdp->fd_knhashmask != 0) {
 		for (i = 0; i < fdp->fd_knhashmask + 1; i++) {
 			kqueue_doclose(kq, &fdp->fd_knhash[i], -1);
+		}
+	}
 	mutex_exit(&fdp->fd_lock);
 	KASSERT(kq->kq_count == 0);
 	mutex_destroy(&kq->kq_lock);
 	cv_destroy(&kq->kq_cv);
 	seldestroy(&kq->kq_sel);
 	kmem_free(kq, sizeof(*kq));
 	return (0);
+}
 /*
  * struct fileops kqfilter method for a kqueue descriptor.
  * Event triggered when monitored kqueue changes.
  */
 static int
 kqueue_kqfilter(file_t *fp, struct knote *kn)
+{
 	struct kqueue *kq;
 	kq = ((file_t *)kn->kn_obj)->f_data;
 	KASSERT(fp == kn->kn_obj);
 	if (kn->kn_filter != EVFILT_READ)
 		return 1;
 	kn->kn_fop = &kqread_filtops;
 	mutex_enter(&kq->kq_lock);
 	SLIST_INSERT_HEAD(&kq->kq_sel.sel_klist, kn, kn_selnext);
 	mutex_exit(&kq->kq_lock);
 	return 0;
+}
 /*
  * Walk down a list of knotes, activating them if their event has
  * triggered.  The caller's object lock (e.g. device driver lock)
  * must be held.
  */
 void
 knote(struct klist *list, long hint)
+{
 	struct knote *kn, *tmpkn;
 	SLIST_FOREACH_SAFE(kn, list, kn_selnext, tmpkn) {
 		if ((*kn->kn_fop->f_event)(kn, hint))
 			knote_activate(kn);
+	}
+}
 /*
  * Remove all knotes referencing a specified fd
  */
 void
 knote_fdclose(int fd)
+{
 	struct klist *list;
 	struct knote *kn;
 	filedesc_t *fdp;
 	fdp = curlwp->l_fd;
 	list = (struct klist *)&fdp->fd_dt->dt_ff[fd]->ff_knlist;
 	mutex_enter(&fdp->fd_lock);
 	while ((kn = SLIST_FIRST(list)) != NULL) {
 		knote_detach(kn, fdp, true);
 		mutex_enter(&fdp->fd_lock);
+	}
 	mutex_exit(&fdp->fd_lock);
+}
 /*
  * Drop knote.  Called with fdp->fd_lock held, and will drop before
  * returning.
  */
 static void
 knote_detach(struct knote *kn, filedesc_t *fdp, bool dofop)
+{
 	struct klist *list;
 	struct kqueue *kq;
 	kq = kn->kn_kq;
 	KASSERT((kn->kn_status & KN_MARKER) == 0);
 	KASSERT(mutex_owned(&fdp->fd_lock));
 	/* Remove from monitored object. */