40481dbabb
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> |
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| .. | ||
| CVSChangeLogs.old | ||
| cygserver | ||
| cygwin | ||
| doc | ||
| lsaauth | ||
| testsuite | ||
| utils | ||
| acinclude.m4 | ||
| aclocal.m4 | ||
| autogen.sh | ||
| c++wrap | ||
| ccwrap | ||
| config.guess | ||
| config.sub | ||
| configure | ||
| configure.ac | ||
| configure.cygwin | ||
| CONTRIBUTORS | ||
| COPYING | ||
| COPYING.LIB | ||
| CYGWIN_LICENSE | ||
| install-sh | ||
| Makefile.common | ||
| Makefile.in | ||
| README | ||
THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. Cygwin documentation is available on the net at https://cygwin.com You might especially be interested in https://cygwin.com/faq/faq.html#faq.programming.building-cygwin