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Differential D40445

ndp: Prepare for pending tcpdump update
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Authored by jrm on Jun 7 2023, 2:27 AM.
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emaste
jhb
melifaro
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rG1cdec2832d05: ndp: Prepare for pending tcpdump update
Summary

npd makes use of gmt2local, however that library has been removed from
tcpdump. Add utc_offset() as a substitute.

Diff Detail

Repository
rG FreeBSD src repository
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Lint Skipped
Unit
Tests Skipped
Build Status
Buildable 51962
Build 48853: arc lint + arc unit

Event Timeline

jrm created this revision.Jun 7 2023, 2:27 AM
Herald added a subscriber: imp. · View Herald TranscriptJun 7 2023, 2:27 AM
jrm requested review of this revision.Jun 7 2023, 2:27 AM
Harbormaster completed remote builds in B51938: Diff 122906.Jun 7 2023, 2:27 AM
jrm added a comment.Jun 7 2023, 2:29 AM

Should we be concerned that the long tm->tm_gmtoff will be implicitly cast as int32_t when it's returned?

jrm updated this revision to Diff 122947.Jun 7 2023, 4:20 PM

Make utc_offset() argument match gmt2local() and make it a static function.

Harbormaster completed remote builds in B51959: Diff 122947.Jun 7 2023, 4:20 PM
jrm added reviewers: jhb, melifaro.Jun 7 2023, 4:22 PM
melifaro accepted this revision.Jun 7 2023, 4:36 PM
This revision is now accepted and ready to land.Jun 7 2023, 4:36 PM
emaste accepted this revision.Jun 7 2023, 4:48 PM

This seems OK as a minimal change.

We may want to follow tcpdump's ts_print() more closely though, in a subsequent change.

jrm updated this revision to Diff 122949.Jun 7 2023, 6:07 PM

Assert that the value stored in tm->tm_gmtoff will fit in a int32_t.

This revision now requires review to proceed.Jun 7 2023, 6:07 PM
Harbormaster completed remote builds in B51960: Diff 122949.Jun 7 2023, 6:07 PM
jhb added a comment.Jun 7 2023, 6:56 PM

Nit: s/npd/ndp/ in commit log

usr.sbin/ndp/ndp.c
187

Given this is only used with a value of 0, I would maybe go ahead and assume that and remove the argument from here entirely, that is, have it start as:

static int32_t
utc_offset(void)
{
    struct tm *tm;
    time t;

    t = time(NULL);
    tm = localtime(&t);
...
197
jrm updated this revision to Diff 122953.Jun 7 2023, 8:53 PM

Revert back to function with no arguments. Fix typo and formatting.

Harbormaster completed remote builds in B51962: Diff 122953.Jun 7 2023, 8:53 PM
jrm marked 2 inline comments as done.Jun 7 2023, 8:54 PM
This revision was not accepted when it landed; it landed in state Needs Review.Jun 8 2023, 2:00 AM
Closed by commit rG1cdec2832d05: ndp: Prepare for pending tcpdump update (authored by jrm). · Explain Why
This revision was automatically updated to reflect the committed changes.
jrm added a commit: rG1cdec2832d05: ndp: Prepare for pending tcpdump update.

Revision Contents
Changeset List

PathSize
usr.sbin/
ndp/
6 lines
20 lines
1 line

Diff 122953

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usr.sbin/ndp/Makefile

Show All 32 Lines
.Lb libc .Lb libc
.Sh SYNOPSIS .Sh SYNOPSIS
.In sys/event.h .In sys/event.h
.Ft int .Ft int
.Fn kqueue "void" .Fn kqueue "void"
.Ft int .Ft int
.Fn kqueuex "u_int flags" .Fn kqueuex "u_int flags"
.Ft int .Ft int
.Fn kqueue1 "int flags"
.Ft int
.Fo kevent .Fo kevent
.Fa "int kq" .Fa "int kq"
.Fa "const struct kevent *changelist" .Fa "const struct kevent *changelist"
.Fa "int nchanges" .Fa "int nchanges"
.Fa "struct kevent *eventlist" .Fa "struct kevent *eventlist"
.Fa "int nevents" .Fa "int nevents"
.Fa "const struct timespec *timeout" .Fa "const struct timespec *timeout"
.Fc .Fc
Show All 38 Lines
is called without the is called without the
.Dv RFFDG .Dv RFFDG
flag, then the descriptor table is shared, flag, then the descriptor table is shared,
which will allow sharing of the kqueue between two processes. which will allow sharing of the kqueue between two processes.
.Pp .Pp
The The
.Fn kqueuex .Fn kqueuex
system call also creates a new kernel event queue, and additionally takes system call also creates a new kernel event queue, and additionally takes
the a
.Fa flags .Fa flags
argument, which is a bitwise-inclusive OR of the following flags: argument, which is a bitwise-inclusive OR of the following flags:
.Bl -tag -width "KQUEUE_CLOEXEC" .Bl -tag -width "KQUEUE_CLOEXEC"
.It Fa KQUEUE_CLOEXEC .It Dv KQUEUE_CLOEXEC
The returned file descriptor is automatically closed on The returned file descriptor is automatically closed on
.Xr execve 2 .Xr execve 2
.El .El
.Pp
The The
.Ql fd = kqueue() .Fn kqueue
call is equivalent to system call is equivalent to calling
.Ql fd = kqueuex(0) . .Fn kqueuex
with
.Fa flags
set to 0.
.Pp .Pp
For compatibility with The
.Nx ,
the
.Fn kqueue1 .Fn kqueue1
function is provided, which accepts the function exists for compatibility with
emasteUnsubmitted
Not Done
Inline Actions

The "also" here seems somewhat out of place to me for some reason but I'm not quite sure why. Maybe "Also, for compatibility with NetBSD the..." or "The kqueue1 function is also provided, for compatibility with NetBSD. It accepts..."

emaste: The "also" here seems somewhat out of place to me for some reason but I'm not quite sure why.
.Dv O_CLOEXEC .Nx .
flag with the expected semantic. The
.Fa flags
argument accepts zero or more of the following values:
.Bl -tag -width O_CLOEXEC
.It Dv O_CLOEXEC
The returned file descriptor is automatically closed on
.Xr execve 2
.El
.Pp .Pp
The The
.Fn kevent .Fn kevent
system call system call
is used to register events with the queue, and return any pending is used to register events with the queue, and return any pending
events to the user. events to the user.
The The
.Fa changelist .Fa changelist
▲ Show 20 Lines • Show All 83 Lines • ▼ Show 20 Lines
.It Fa fflags .It Fa fflags
Filter-specific flags. Filter-specific flags.
.It Fa data .It Fa data
Filter-specific data value. Filter-specific data value.
.It Fa udata .It Fa udata
Opaque user-defined value passed through the kernel unchanged. Opaque user-defined value passed through the kernel unchanged.
.It Fa ext .It Fa ext
Extended data passed to and from kernel. Extended data passed to and from kernel.
The The meaning of the
.Fa ext[0] .Fa ext[0]
and and
.Fa ext[1] .Fa ext[1]
members use is defined by the filter. members is defined by the filter.
If the filter does not use them, the members are copied unchanged. If a filter does not use them,
these members are passed through the kernel unchanged.
The The
.Fa ext[2] .Fa ext[2]
and and
.Fa ext[3] .Fa ext[3]
members are always passed through the kernel as-is, members are always passed through the kernel unchanged,
making additional context available to application. providing additional user-defined values.
.El .El
.Pp .Pp
The The
.Va flags .Va flags
field can contain the following values: field can contain the following values:
.Bl -tag -width EV_DISPATCH .Bl -tag -width EV_KEEPUDATA
.It Dv EV_ADD .It Dv EV_ADD
Adds the event to the kqueue. Adds the event to the kqueue.
Re-adding an existing event Re-adding an existing event
will modify the parameters of the original event, and not result will modify the parameters of the original event, and not result
in a duplicate entry. in a duplicate entry.
Adding an event automatically enables it, Adding an event automatically enables it,
unless overridden by the EV_DISABLE flag. unless overridden by the EV_DISABLE flag.
.It Dv EV_ENABLE .It Dv EV_ENABLE
Show All 25 Lines
.Va data .Va data
field will be zero. field will be zero.
Note that if this flag is encountered and there is no remaining space in Note that if this flag is encountered and there is no remaining space in
.Fa eventlist .Fa eventlist
to hold the to hold the
.Dv EV_ERROR .Dv EV_ERROR
event, then subsequent changes will not get processed. event, then subsequent changes will not get processed.
.It Dv EV_ONESHOT .It Dv EV_ONESHOT
Causes the event to return only the first occurrence of the filter Return only the first occurrence of the filter
being triggered. being triggered.
After the user retrieves the event from the kqueue, After the user retrieves the event from the kqueue,
it is deleted. it is deleted.
.It Dv EV_CLEAR .It Dv EV_CLEAR
After the event is retrieved by the user, its state is reset. Reset the state of the event after it is retrieved by the user.
This is useful for filters which report state transitions This is useful for filters which report state transitions
instead of the current state. instead of the current state.
Note that some filters may automatically Note that some filters may automatically
set this flag internally. set this flag internally.
.It Dv EV_EOF .It Dv EV_EOF
Filters may set this flag to indicate filter-specific EOF condition. Filters may set this flag to indicate filter-specific EOF condition.
.It Dv EV_ERROR .It Dv EV_ERROR
See See
.Sx RETURN VALUES .Sx RETURN VALUES
below. below.
.It Dv EV_KEEPUDATA .It Dv EV_KEEPUDATA
Causes Preserve the
.Fn kevent
to leave unchanged any
.Fa udata .Fa udata
associated with an existing event. associated with an existing event.
This allows other aspects of the event to be modified without requiring the This allows other aspects of the event to be modified without requiring the
caller to know the caller to know the
.Fa udata .Fa udata
value presently associated. value previously registered with the event.
This is especially useful with This is especially useful with
.Dv NOTE_TRIGGER .Dv NOTE_TRIGGER
or flags like or
.Dv EV_ENABLE . .Dv EV_ENABLE .
This flag may not be used with This flag may not be used with
.Dv EV_ADD . .Dv EV_ADD .
.El .El
.Pp .Pp
The predefined system filters are listed below. The predefined system filters are listed below.
Arguments may be passed to and from the filter via the Arguments may be passed to and from the filter via the
.Va fflags .Va fflags
▲ Show 20 Lines • Show All 557 Lines • ▼ Show 20 Lines
.Re .Re
.Sh HISTORY .Sh HISTORY
The The
.Fn kqueue .Fn kqueue
and and
.Fn kevent .Fn kevent
system calls first appeared in system calls first appeared in
.Fx 4.1 . .Fx 4.1 .
The
.Fn kqueuex
system call
and
.Fn kevent1
function first appeared in
.Fx 14.0 .
.Sh AUTHORS .Sh AUTHORS
The The
.Fn kqueue .Fn kqueue
system and this manual page were written by system and this manual page were written by
.An Jonathan Lemon Aq Mt jlemon@FreeBSD.org . .An Jonathan Lemon Aq Mt jlemon@FreeBSD.org .
.Sh BUGS .Sh BUGS
.Pp .Pp
In versions older than In versions older than
.Fx 12.0 , .Fx 12.0 ,
.In sys/event.h .In sys/event.h
failed to parse without including failed to parse without including
.In sys/types.h .In sys/types.h
manually. manually.
View Options

usr.sbin/ndp/ndp.c

Show All 32 Lines
.Lb libc .Lb libc
.Sh SYNOPSIS .Sh SYNOPSIS
.In sys/event.h .In sys/event.h
.Ft int .Ft int
.Fn kqueue "void" .Fn kqueue "void"
.Ft int .Ft int
.Fn kqueuex "u_int flags" .Fn kqueuex "u_int flags"
.Ft int .Ft int
.Fn kqueue1 "int flags"
.Ft int
.Fo kevent .Fo kevent
.Fa "int kq" .Fa "int kq"
.Fa "const struct kevent *changelist" .Fa "const struct kevent *changelist"
.Fa "int nchanges" .Fa "int nchanges"
.Fa "struct kevent *eventlist" .Fa "struct kevent *eventlist"
.Fa "int nevents" .Fa "int nevents"
.Fa "const struct timespec *timeout" .Fa "const struct timespec *timeout"
.Fc .Fc
Show All 38 Lines
is called without the is called without the
.Dv RFFDG .Dv RFFDG
flag, then the descriptor table is shared, flag, then the descriptor table is shared,
which will allow sharing of the kqueue between two processes. which will allow sharing of the kqueue between two processes.
.Pp .Pp
The The
.Fn kqueuex .Fn kqueuex
system call also creates a new kernel event queue, and additionally takes system call also creates a new kernel event queue, and additionally takes
the a
.Fa flags .Fa flags
argument, which is a bitwise-inclusive OR of the following flags: argument, which is a bitwise-inclusive OR of the following flags:
.Bl -tag -width "KQUEUE_CLOEXEC" .Bl -tag -width "KQUEUE_CLOEXEC"
.It Fa KQUEUE_CLOEXEC .It Dv KQUEUE_CLOEXEC
The returned file descriptor is automatically closed on The returned file descriptor is automatically closed on
.Xr execve 2 .Xr execve 2
.El .El
.Pp
The The
.Ql fd = kqueue() .Fn kqueue
call is equivalent to system call is equivalent to calling
.Ql fd = kqueuex(0) . .Fn kqueuex
with
.Fa flags
set to 0.
.Pp .Pp
For compatibility with The
.Nx ,
the
.Fn kqueue1 .Fn kqueue1
function is provided, which accepts the function exists for compatibility with
emasteUnsubmitted
Not Done
Inline Actions

The "also" here seems somewhat out of place to me for some reason but I'm not quite sure why. Maybe "Also, for compatibility with NetBSD the..." or "The kqueue1 function is also provided, for compatibility with NetBSD. It accepts..."

emaste: The "also" here seems somewhat out of place to me for some reason but I'm not quite sure why.
.Dv O_CLOEXEC .Nx .
flag with the expected semantic. The
.Fa flags
argument accepts zero or more of the following values:
.Bl -tag -width O_CLOEXEC
.It Dv O_CLOEXEC
The returned file descriptor is automatically closed on
.Xr execve 2
.El
.Pp .Pp
The The
.Fn kevent .Fn kevent
system call system call
is used to register events with the queue, and return any pending is used to register events with the queue, and return any pending
events to the user. events to the user.
The The
.Fa changelist .Fa changelist
▲ Show 20 Lines • Show All 83 Lines • ▼ Show 20 Lines
.It Fa fflags .It Fa fflags
Filter-specific flags. Filter-specific flags.
.It Fa data .It Fa data
Filter-specific data value. Filter-specific data value.
.It Fa udata .It Fa udata
Opaque user-defined value passed through the kernel unchanged. Opaque user-defined value passed through the kernel unchanged.
.It Fa ext .It Fa ext
Extended data passed to and from kernel. Extended data passed to and from kernel.
The The meaning of the
.Fa ext[0] .Fa ext[0]
and and
.Fa ext[1] .Fa ext[1]
members use is defined by the filter. members is defined by the filter.
If the filter does not use them, the members are copied unchanged. If a filter does not use them,
these members are passed through the kernel unchanged.
The The
.Fa ext[2] .Fa ext[2]
and and
.Fa ext[3] .Fa ext[3]
members are always passed through the kernel as-is, members are always passed through the kernel unchanged,
making additional context available to application. providing additional user-defined values.
.El .El
.Pp .Pp
The The
.Va flags .Va flags
field can contain the following values: field can contain the following values:
.Bl -tag -width EV_DISPATCH .Bl -tag -width EV_KEEPUDATA
.It Dv EV_ADD .It Dv EV_ADD
Adds the event to the kqueue. Adds the event to the kqueue.
Re-adding an existing event Re-adding an existing event
will modify the parameters of the original event, and not result will modify the parameters of the original event, and not result
in a duplicate entry. in a duplicate entry.
Adding an event automatically enables it, Adding an event automatically enables it,
unless overridden by the EV_DISABLE flag. unless overridden by the EV_DISABLE flag.
.It Dv EV_ENABLE .It Dv EV_ENABLE
Show All 25 Lines
.Va data .Va data
field will be zero. field will be zero.
Note that if this flag is encountered and there is no remaining space in Note that if this flag is encountered and there is no remaining space in
.Fa eventlist .Fa eventlist
to hold the to hold the
.Dv EV_ERROR .Dv EV_ERROR
event, then subsequent changes will not get processed. event, then subsequent changes will not get processed.
.It Dv EV_ONESHOT .It Dv EV_ONESHOT
Causes the event to return only the first occurrence of the filter Return only the first occurrence of the filter
being triggered. being triggered.
After the user retrieves the event from the kqueue, After the user retrieves the event from the kqueue,
it is deleted. it is deleted.
.It Dv EV_CLEAR .It Dv EV_CLEAR
After the event is retrieved by the user, its state is reset. Reset the state of the event after it is retrieved by the user.
This is useful for filters which report state transitions This is useful for filters which report state transitions
instead of the current state. instead of the current state.
Note that some filters may automatically Note that some filters may automatically
set this flag internally. set this flag internally.
.It Dv EV_EOF .It Dv EV_EOF
Filters may set this flag to indicate filter-specific EOF condition. Filters may set this flag to indicate filter-specific EOF condition.
.It Dv EV_ERROR .It Dv EV_ERROR
See See
.Sx RETURN VALUES .Sx RETURN VALUES
below. below.
.It Dv EV_KEEPUDATA .It Dv EV_KEEPUDATA
Causes Preserve the
.Fn kevent
to leave unchanged any
.Fa udata .Fa udata
associated with an existing event. associated with an existing event.
This allows other aspects of the event to be modified without requiring the This allows other aspects of the event to be modified without requiring the
caller to know the caller to know the
.Fa udata .Fa udata
value presently associated. value previously registered with the event.
This is especially useful with This is especially useful with
.Dv NOTE_TRIGGER .Dv NOTE_TRIGGER
or flags like or
.Dv EV_ENABLE . .Dv EV_ENABLE .
This flag may not be used with This flag may not be used with
.Dv EV_ADD . .Dv EV_ADD .
.El .El
.Pp .Pp
The predefined system filters are listed below. The predefined system filters are listed below.
Arguments may be passed to and from the filter via the Arguments may be passed to and from the filter via the
.Va fflags .Va fflags
▲ Show 20 Lines • Show All 557 Lines • ▼ Show 20 Lines
.Re .Re
.Sh HISTORY .Sh HISTORY
The The
.Fn kqueue .Fn kqueue
and and
.Fn kevent .Fn kevent
system calls first appeared in system calls first appeared in
.Fx 4.1 . .Fx 4.1 .
The
.Fn kqueuex
system call
and
.Fn kevent1
function first appeared in
.Fx 14.0 .
.Sh AUTHORS .Sh AUTHORS
The The
.Fn kqueue .Fn kqueue
system and this manual page were written by system and this manual page were written by
.An Jonathan Lemon Aq Mt jlemon@FreeBSD.org . .An Jonathan Lemon Aq Mt jlemon@FreeBSD.org .
.Sh BUGS .Sh BUGS
.Pp .Pp
In versions older than In versions older than
.Fx 12.0 , .Fx 12.0 ,
.In sys/event.h .In sys/event.h
failed to parse without including failed to parse without including
.In sys/types.h .In sys/types.h
manually. manually.
View Options

usr.sbin/ndp/ndp_netlink.c

Show All 32 Lines
.Lb libc .Lb libc
.Sh SYNOPSIS .Sh SYNOPSIS
.In sys/event.h .In sys/event.h
.Ft int .Ft int
.Fn kqueue "void" .Fn kqueue "void"
.Ft int .Ft int
.Fn kqueuex "u_int flags" .Fn kqueuex "u_int flags"
.Ft int .Ft int
.Fn kqueue1 "int flags"
.Ft int
.Fo kevent .Fo kevent
.Fa "int kq" .Fa "int kq"
.Fa "const struct kevent *changelist" .Fa "const struct kevent *changelist"
.Fa "int nchanges" .Fa "int nchanges"
.Fa "struct kevent *eventlist" .Fa "struct kevent *eventlist"
.Fa "int nevents" .Fa "int nevents"
.Fa "const struct timespec *timeout" .Fa "const struct timespec *timeout"
.Fc .Fc
Show All 38 Lines
is called without the is called without the
.Dv RFFDG .Dv RFFDG
flag, then the descriptor table is shared, flag, then the descriptor table is shared,
which will allow sharing of the kqueue between two processes. which will allow sharing of the kqueue between two processes.
.Pp .Pp
The The
.Fn kqueuex .Fn kqueuex
system call also creates a new kernel event queue, and additionally takes system call also creates a new kernel event queue, and additionally takes
the a
.Fa flags .Fa flags
argument, which is a bitwise-inclusive OR of the following flags: argument, which is a bitwise-inclusive OR of the following flags:
.Bl -tag -width "KQUEUE_CLOEXEC" .Bl -tag -width "KQUEUE_CLOEXEC"
.It Fa KQUEUE_CLOEXEC .It Dv KQUEUE_CLOEXEC
The returned file descriptor is automatically closed on The returned file descriptor is automatically closed on
.Xr execve 2 .Xr execve 2
.El .El
.Pp
The The
.Ql fd = kqueue() .Fn kqueue
call is equivalent to system call is equivalent to calling
.Ql fd = kqueuex(0) . .Fn kqueuex
with
.Fa flags
set to 0.
.Pp .Pp
For compatibility with The
.Nx ,
the
.Fn kqueue1 .Fn kqueue1
function is provided, which accepts the function exists for compatibility with
emasteUnsubmitted
Not Done
Inline Actions

The "also" here seems somewhat out of place to me for some reason but I'm not quite sure why. Maybe "Also, for compatibility with NetBSD the..." or "The kqueue1 function is also provided, for compatibility with NetBSD. It accepts..."

emaste: The "also" here seems somewhat out of place to me for some reason but I'm not quite sure why.
.Dv O_CLOEXEC .Nx .
flag with the expected semantic. The
.Fa flags
argument accepts zero or more of the following values:
.Bl -tag -width O_CLOEXEC
.It Dv O_CLOEXEC
The returned file descriptor is automatically closed on
.Xr execve 2
.El
.Pp .Pp
The The
.Fn kevent .Fn kevent
system call system call
is used to register events with the queue, and return any pending is used to register events with the queue, and return any pending
events to the user. events to the user.
The The
.Fa changelist .Fa changelist
▲ Show 20 Lines • Show All 83 Lines • ▼ Show 20 Lines
.It Fa fflags .It Fa fflags
Filter-specific flags. Filter-specific flags.
.It Fa data .It Fa data
Filter-specific data value. Filter-specific data value.
.It Fa udata .It Fa udata
Opaque user-defined value passed through the kernel unchanged. Opaque user-defined value passed through the kernel unchanged.
.It Fa ext .It Fa ext
Extended data passed to and from kernel. Extended data passed to and from kernel.
The The meaning of the
.Fa ext[0] .Fa ext[0]
and and
.Fa ext[1] .Fa ext[1]
members use is defined by the filter. members is defined by the filter.
If the filter does not use them, the members are copied unchanged. If a filter does not use them,
these members are passed through the kernel unchanged.
The The
.Fa ext[2] .Fa ext[2]
and and
.Fa ext[3] .Fa ext[3]
members are always passed through the kernel as-is, members are always passed through the kernel unchanged,
making additional context available to application. providing additional user-defined values.
.El .El
.Pp .Pp
The The
.Va flags .Va flags
field can contain the following values: field can contain the following values:
.Bl -tag -width EV_DISPATCH .Bl -tag -width EV_KEEPUDATA
.It Dv EV_ADD .It Dv EV_ADD
Adds the event to the kqueue. Adds the event to the kqueue.
Re-adding an existing event Re-adding an existing event
will modify the parameters of the original event, and not result will modify the parameters of the original event, and not result
in a duplicate entry. in a duplicate entry.
Adding an event automatically enables it, Adding an event automatically enables it,
unless overridden by the EV_DISABLE flag. unless overridden by the EV_DISABLE flag.
.It Dv EV_ENABLE .It Dv EV_ENABLE
Show All 25 Lines
.Va data .Va data
field will be zero. field will be zero.
Note that if this flag is encountered and there is no remaining space in Note that if this flag is encountered and there is no remaining space in
.Fa eventlist .Fa eventlist
to hold the to hold the
.Dv EV_ERROR .Dv EV_ERROR
event, then subsequent changes will not get processed. event, then subsequent changes will not get processed.
.It Dv EV_ONESHOT .It Dv EV_ONESHOT
Causes the event to return only the first occurrence of the filter Return only the first occurrence of the filter
being triggered. being triggered.
After the user retrieves the event from the kqueue, After the user retrieves the event from the kqueue,
it is deleted. it is deleted.
.It Dv EV_CLEAR .It Dv EV_CLEAR
After the event is retrieved by the user, its state is reset. Reset the state of the event after it is retrieved by the user.
This is useful for filters which report state transitions This is useful for filters which report state transitions
instead of the current state. instead of the current state.
Note that some filters may automatically Note that some filters may automatically
set this flag internally. set this flag internally.
.It Dv EV_EOF .It Dv EV_EOF
Filters may set this flag to indicate filter-specific EOF condition. Filters may set this flag to indicate filter-specific EOF condition.
.It Dv EV_ERROR .It Dv EV_ERROR
See See
.Sx RETURN VALUES .Sx RETURN VALUES
below. below.
.It Dv EV_KEEPUDATA .It Dv EV_KEEPUDATA
Causes Preserve the
.Fn kevent
to leave unchanged any
.Fa udata .Fa udata
associated with an existing event. associated with an existing event.
This allows other aspects of the event to be modified without requiring the This allows other aspects of the event to be modified without requiring the
caller to know the caller to know the
.Fa udata .Fa udata
value presently associated. value previously registered with the event.
This is especially useful with This is especially useful with
.Dv NOTE_TRIGGER .Dv NOTE_TRIGGER
or flags like or
.Dv EV_ENABLE . .Dv EV_ENABLE .
This flag may not be used with This flag may not be used with
.Dv EV_ADD . .Dv EV_ADD .
.El .El
.Pp .Pp
The predefined system filters are listed below. The predefined system filters are listed below.
Arguments may be passed to and from the filter via the Arguments may be passed to and from the filter via the
.Va fflags .Va fflags
▲ Show 20 Lines • Show All 557 Lines • ▼ Show 20 Lines
.Re .Re
.Sh HISTORY .Sh HISTORY
The The
.Fn kqueue .Fn kqueue
and and
.Fn kevent .Fn kevent
system calls first appeared in system calls first appeared in
.Fx 4.1 . .Fx 4.1 .
The
.Fn kqueuex
system call
and
.Fn kevent1
function first appeared in
.Fx 14.0 .
.Sh AUTHORS .Sh AUTHORS
The The
.Fn kqueue .Fn kqueue
system and this manual page were written by system and this manual page were written by
.An Jonathan Lemon Aq Mt jlemon@FreeBSD.org . .An Jonathan Lemon Aq Mt jlemon@FreeBSD.org .
.Sh BUGS .Sh BUGS
.Pp .Pp
In versions older than In versions older than
.Fx 12.0 , .Fx 12.0 ,
.In sys/event.h .In sys/event.h
failed to parse without including failed to parse without including
.In sys/types.h .In sys/types.h
manually. manually.