by making it accept some open(2) flags. More precisely, only
O_CLOEXEC is supported, the flag is translated into the KQUEUE_CLOEXEC flag
for kqueuex(2), and O_NONBLOCK is silently ignored.
Reported and tested by: vishwin
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D39377
There is no real need to close descriptors before a process exits, but
these close calls demonstrate by example that kqueue descriptors occupy
the same namespace as other file descriptors.
Reviewed by: fernape, markj
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D39376
The error control was not properly implemented. "changelist" is const, hence
event.flags is never changed by the syscall.
PR: 196844
Reported by: eugen@
Reviewed by: PauAmma <pauamma@gundo.com>
Approved by: eugen@
Fixes: 8c231786f0
A BPF descriptor only has an associated interface descriptor once it is
attached to an interface, e.g., with BIOCSETIF. Avoid dereferencing a
NULL pointer in filt_bpfwrite() if the BPF descriptor is not attached.
Reviewed by: ae
Reported by: syzbot+ae45d5166afe15a5a21d@syzkaller.appspotmail.com
Fixes: ded77e0237 ("Allow the BPF to be select for write.")
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D32561
When this flag is set, operations that update an existing kevent will
not change the udata field. This can be used to NOTE_TRIGGER or
EV_{EN,DIS}ABLE events without overwriting the stashed pointer.
Reviewed by: Domagoj Stolfa <domagoj.stolfa@gmail.com>
Obtained from: CheriBSD
Sponsored by: Microsoft
Differential Revision: https://reviews.freebsd.org/D30286
Previously, a negative change list length would be treated the same as
an empty change list. A negative event list length would result in
bogus copyouts. Make kevent(2) return EINVAL for both cases so that
application bugs are more easily found, and to be more robust against
future changes to kevent internals.
Reviewed by: imp, kib
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D30480
- Add STANDARDS and HISTORY sections within the appropriate manpages
- Mention two USENIX papers within kqueue(2) and strlcpy(3)
Reviewed by: bcr (mentor)
Approved by: bcr (mentor)
Obtained from: NetBSD
MFC after: 7 days
Differential Revision: https://reviews.freebsd.org/D24650
Contrary to the kevent man page, EV_EOF on a fifo is not cleared by
EV_CLEAR. Modify the read and write filters to clear EV_EOF when the
fifo's PIPE_EOF flag is clear, and update the man page to document the
new behaviour.
Modify the write filter to return the amount of buffer space available
even if no readers are present. This matches the behaviour for sockets.
When reading from a pipe, only call pipeselwakeup() if some data was
actually read. This prevents the continuous re-triggering of a
EVFILT_READ event on EOF when in edge-triggered mode.
PR: 203366, 224615
Submitted by: Jan Kokemüller <jan.kokemueller@gmail.com>
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D24528
In the below-referenced PR, a case is attached of a simple reproducer that
exhibits suboptimal behavior: EVFILT_READ and EVFILT_WRITE being set in the
same kevent(2) call will only honor the first one. This is, in-fact, how
it's supposed to work.
A read of the manpage leads me to believe we could be more clear about this;
right now there's a logical leap to make in the relevant statement: "When
passed as input, it forces EV_ERROR to always be returned." -- the logical
leap being that this indicates the caller should have allocated space for
the change to be returned with EV_ERROR indicated in the events, or
subsequent filters will get dropped on the floor.
Another possible workaround that accomplishes similar effect without needing
space for all events is just setting EV_RECEIPT on the final change being
passed in; if any errored before it, the kqueue would not be drained. If we
made it to the final change with EV_RECEIPT set, then we would return that
one with EV_ERROR and still not drain the kqueue. This would seem to not be
all that advisable.
PR: 229741
MFC after: 1 week
If a timer is updated (re-added) with a different time period
(specified in the .data field of the kevent), the new time period has
no effect; the timer will not expire until the original time has
elapsed. This violates the documented behavior as the kqueue(2) man
page says (in part) "Re-adding an existing event will modify the
parameters of the original event, and not result in a duplicate
entry."
This modification, adapted from a patch submitted by cem@ to PR214987,
fixes the kqueue system to allow updating a timer entry. The
kevent timer behavior is changed to:
* When a timer is re-added, update the timer parameters to and
re-start the timer using the new parameters.
* Allow updating both active and already expired timers.
* When the timer has already expired, dequeue any undelivered events
and clear the count of expirations.
All of these changes address the original PR and also bring the
FreeBSD and macOS kevent timer behaviors into agreement.
A few other changes were made along the way:
* Update the kqueue(2) man page to reflect the new timer behavior.
* Fix man page style issues in kqueue(2) diagnosed by igor.
* Update the timer libkqueue system test to test for the updated
timer behavior.
* Fix the (test) libkqueue common.h file so that it includes
config.h which defines various HAVE_* feature defines, before the
#if tests for such variables in common.h. This enables the use of
the actual err(3) family of functions.
* Fix the usages of the err(3) functions in the tests for incorrect
type of variables. Those were formerly undiagnosed due to the
disablement of the err(3) functions (see previous bullet point).
PR: 214987
Reported by: Brian Wellington <bwelling@xbill.org>
Reviewed by: kib
MFC after: 1 week
Relnotes: yes
Sponsored by: Dell EMC
Differential Revision: https://reviews.freebsd.org/D15778
This change implements NOTE_ABSTIME flag for EVFILT_TIMER, which
specifies that the data field contains absolute time to fire the
event.
To make this useful, data member of the struct kevent must be extended
to 64bit. Using the opportunity, I also added ext members. This
changes struct kevent almost to Apple struct kevent64, except I did
not changed type of ident and udata, the later would cause serious API
incompatibilities.
The type of ident was kept uintptr_t since EVFILT_AIO returns a
pointer in this field, and e.g. CHERI is sensitive to the type
(discussed with brooks, jhb).
Unlike Apple kevent64, symbol versioning allows us to claim ABI
compatibility and still name the new syscall kevent(2). Compat shims
are provided for both host native and compat32.
Requested by: bapt
Reviewed by: bapt, brooks, ngie (previous version)
Sponsored by: The FreeBSD Foundation
Differential revision: https://reviews.freebsd.org/D11025
Now that <sys/event.h> can be included on its own, adjust the manual
page accordingly. Remove both unnecessary #include statements from the
synopsis and the example code.
While there, also add a note to the BUGS section to mention that
previous versions of this header file still depend on <sys/types.h>.
Reviewed by: ngie, vangyzen
Differential Revision: https://reviews.freebsd.org/D9605
While there, order EVFILT_VNODE notes descriptions alphabetically.
Based on submission, and tested by: Vladimir Kondratyev <wulf@cicgroup.ru>
MFC after: 2 weeks
the monitored directory as the result of rename(2) operation. The
renames staying in the directory are not reported.
Submitted by: Vladimir Kondratyev <wulf@cicgroup.ru>
MFC after: 2 weeks
a basic usage example. Although it is an
untypical example for the use of kqueue, it is
better than nothing and should get people started.
PR: 196844
Submitted by: fernando.apesteguia@gmail.com
Reviewed by: kib
Approved by: kib
MFC after: 5 days
Differential Revision: https://reviews.freebsd.org/D6082
It looks like EVFILT_READ and EVFILT_WRITE trigger under the same
conditions as poll()'s POLLRDNORM and POLLWRNORM as described by POSIX.
The only difference is that POLLRDNORM has to be triggered on regular
files unconditionally, whereas EVFILT_READ only triggers when not EOF.
Introduce a new flag, NOTE_FILE_POLL, that can be used to make
EVFILT_READ and EVFILT_WRITE behave identically to poll(). This flag
will be used by cloudlibc's poll() function.
Reviewed by: jmg
Differential Revision: https://reviews.freebsd.org/D3303
Note that to cancel blocked kevent(2) call, changelist must be empty,
since we cannot cancel a call which already made changes to the
process state. And in reverse, call which only makes changes to the
kqueue state, without waiting for an event, is not cancellable. This
makes a natural usage model to migrate kqueue loop to support
cancellation, where existing single kevent(2) call must be split into
two: first uncancellable update of kqueue, then cancellable wait for
events.
Note that this is ABI-incompatible change, but it is believed that
there is no cancel-safe code that relies on kevent(2) not being a
cancellation point. Option to preserve the ABI would be to keep
kevent(2) as is, but add new call with flags to specify cancellation
behaviour, which only value seems to add complications.
Suggested and reviewed by: jilles
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Define the precision macros as bits sets to conform with XNU equivalent.
Test fflags passed for EVFILT_TIMER and return EINVAL in case an invalid flag
is passed.
Phabric: https://phabric.freebsd.org/D421
Reviewed by: kib
kqueue(2) already supports EVFILT_PROC. Add an EVFILT_PROCDESC that
behaves the same, but operates on a procdesc(4) instead. Only implement
NOTE_EXIT for now. The nice thing about NOTE_EXIT is that it also
returns the exit status of the process, meaning that we can now obtain
this value, even if pdwait4(2) is still unimplemented.
Notes:
- Simply reuse EVFILT_NETDEV for EVFILT_PROCDESC. As both of these will
be used on totally different descriptor types, this should not clash.
- Let procdesc_kqops_event() reuse the same structure as filt_proc().
The only difference is that procdesc_kqops_event() should also be able
to deal with the case where the process was already terminated after
registration. Simply test this when hint == 0.
- Fix some style(9) issues in filt_proc() to keep it consistent with the
newly added procdesc_kqops_event().
- Save the exit status of the process in pd->pd_xstat, as we cannot pick
up the proctree_lock from within procdesc_kqops_event().
Discussed on: arch@
Reviewed by: kib@
- NOTE_TRACK has never triggered a NOTE_TRACK event from the parent pid.
If NOTE_FORK is set, the listener will get a NOTE_FORK event from
the parent pid, but not a separate NOTE_TRACK event.
- Explicitly note that the event added to monitor the child process
preserves the fflags from the original event.
- Move the description of NOTE_TRACKERR under NOTE_TRACK as it is not a
bit for the user to set (which is what this list pupports to be).
Also, explicitly note that if an error occurs, the NOTE_CHILD event
will not be generated.
MFC after: 1 week
