- Rename files timer.* to posix_timer.*.
- Reimplement using an OS timer rather than a handcrafted wait loop.
- Use a Slim R/W Lock for synchronization.
- Drop timer chaining. It doesn't server a purpose since all timers
are local only.
- Rename ttstart to itimer_tracker to better reflect its purpose.
It's not the anchor for a timer chain anymore anyway.
- Drop fixup_timers_after_fork. Everything is process-local, nothing
gets inherited.
- Rename timer_tracker::disarm_event to disarm_overrun_event for
better readability.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
- When correcting the next expiration timestamp, the number of
expirations gets computed correctly, just the expiration timestamp
itself is then only incremented by a single interval, rather than
the just computed expired intervals. Fix that.
- drop the local clock variable in timerfd_tracker::create. It doesn't
serve any purpose.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
- split into to __try/__except blocks to make sure
leave_critical_section is always called when required.
- Actually fill time_spec in settime so it_interval is returned
correctly.
- Return all 0 if timer is disarmed.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
The value returned by reading from a timerfd is not an overrun
count in the same sense as for posix timers, it's an expiry counter.
Reflect that in the name.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
- Drop erroneous initial computation of overrun count in settime
for absolute non-realtime clocks. It's repeated in thread_func
and thus counted twice.
- Fix overrun computation for timestamp offsets being a multiple of
the timer interval. The timestamp has to be corrected after the
first offset, otherwise the correction loop counts the intervals
again.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
Non-CLOCK_REALTIME counters always use a relative DueTime in NtSetTimer.
However, relative DueTime has to be negative, but the code
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
- On systems with inexact realtime clock, the current timestamp may
be fractionally smaller than the desired timestamp. This breaks the
computation for incrementing overrun_count so overrun_count may end
up as 0. Expiring the timer with an overrun_count of 0 is a no-go.
Make sure we always increment overrun_count by at least one after
timer expiry.
- Do not expire the timer when another process deletes its timer_tracker.
This, too, may result in a 0 overrun_count.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
Using posix timers "timer_tracker" as base class for timerfd was flawed.
Posix timers are not inherited by child processes and don't survive
execve. The method used by posix timers didn't allow to share timers
between processes. The timers were still per-process timers and worked
entirely separate from each other. Reading from these timers via
different descriptors was only synchronized within the same process.
This does not reflect the timerfd semantics in Linux: The per-file
timers can be dup'ed and survive fork and execve. They are still just
descriptors pointing to the same timer object originally created by
timerfd_create. Synchronization is performed between all descriptor
instances of the same timer, system-wide.
Thus, reimplement timerfd using a timer instance in shared memory,
a kernel timer, and a handful of sync objects.
Every process maintains a per-process timerfd struct on the cygheap
maintaining a per-process thread. Every process sharing the same
timerfd will run this thread checking the state of the timer, similar
to the posix timer thread, just working on the shared objects and
synchronizing its job with each other thread.
Drop the timerfd implementation in the posix timer code and move the
public API to fhandler_timerfd.c. Keep the ttstart timer_tracker
anchor out of "NO_COPY" since the fixup_after_fork code should run to
avoid memory leakage.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
Linux returns EINVAL, "fd is attached to an object which is unsuitable
for writing". If we don't handle write locally, write returns EBADF.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
- Puzzeling: Commit ec98d19a08
changed ttstart to NO_COPY but kept all the code to handle
fixup after fork. Revert to not-NO_COPY and make timerfd
fork work.
- On fixup_after_fork, keep timerfd timers and restart thread
if they were armed in the parent.
- Move timerfd timer_trackers to cygheap. Overload timer_tracker
new and delete methods to handle timers accordingly. This is not
exactly required for fork, but exec will be grateful.
- Give up on TFD_TIMER_CANCEL_ON_SET for now. There's no easy way
to recognize a discontinuous change in a clock.
- Be paranoid when cleaning out ttstart.
- Fix some minor issues.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
- Drop initial overrun computation from timer_tracker::settimer.
It's performed in timer_tracker::thread_func anyway.
- Fix regression in returning correct overrun count narrowed down to
int from timer_getoverrun. This has been introduced by changing
overrun_count_curr to LONG64.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
First cut of a timerfd implementation.
Still TODO:
- fork/exec semantics
- timerfd_settime TFD_TIMER_CANCEL_ON_SET flag
- ioctl(TFD_IOC_SET_TICKS)
- bug fixes
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
In case sigwait_common returns EINTR, read wrongly ignores it,
so read can't be interrupt by a signal. Fix that.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
While FileRenameInformationEx is defined starting with Windows
10 1709 per MSDN, it only starts working in W10 1809, apparently.
Users of 1803 report "Function not implemented".
Introduce wincap_10_1809 and change the version check in
wincapc::init accordingly. Split has_posix_file_info into
has_posix_unlink_semantics and has_posix_rename_semantics.
Enable the latter only starting with W10 1809.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
Allow the signal thread to recognize we're called in consequence of
select on a signalfd. If the signal is part of the wait mask, don't
call any signal handler and don't remove the signal from the queue,
so a subsequent read (or sigwaitinfo/sigtimedwait) still gets the
signal. Instead, just signal the event object at
_cygtls::signalfd_select_wait for the thread running select.
The addition of signalfd_select_wait to _cygtls unearthed the alignment
problem of the context member again. To make sure this doesn't get lost,
improve the related comment in the header file so that this (hopefully)
doesn't get lost (again).
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
First cut of a signalfd implementation.
Still TODO: Non-polling select.
This should mostly work as on Linux except for missing support
for some members of struct signalfd_siginfo, namely ssi_fd,
ssi_band (both SIGIO/SIGPOLL, not fully implemented) and ssi_trapno
(HW exception, required HW support).
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
There's a long-standing bug in select. If we have poll-only
descriptors in the fd set, select overwrites the incoming
fd sets with the polling result. If none of the fds is ready,
select has to loop again. But now the fd sets are set to all
zero and select hangs.
Fix this by utilizing the local fd sets r, w, e as storage for
the incoming fd sets and use them to initialize select_stuff.
If we have to loop, overwritung the incoming fd sets doesn't matter.
While at it, rename r, w, e to readfds_in, writefds_in, exceptfds_in.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
- use int64_t instead of long long
- make is_timer_tracker const
- improve copyright header comment
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
Corinna Vinschen