Hi Ken,
On Jul 16 12:19, Ken Brown via Cygwin-patches wrote:
> There were several flaws in my previous attempt to add support for
> explicitly opening a FIFO multiple times for reading. (By
> "explicitly" I mean by calling open rather than by calling
> fork/exec/dup.) See
>
> https://sourceware.org/pipermail/cygwin/2020-July/245456.html
>
> for one indication of problems
>
> The most important flaw was that I tried to use an indirect,
> unreliable method for determining whether there are writers open.
> This is fixed in the second patch of this series by adding a member
> '_nwriters' to struct fifo_shmem_t, which counts the number of open
> writers.
>
> We now have to give writers access to the shared memory as well as
> readers, so that they can increment _nwriters in open/fork/exec/dup
> and decrement it in close.
>
> The other patches contain miscellaneous fixes/improvements.
>
> Ken Brown (12):
> Cygwin: FIFO: fix problems finding new owner
> Cygwin: FIFO: keep a writer count in shared memory
> Cygwin: fhandler_fifo::hit_eof: improve reliability
> Cygwin: FIFO: reduce I/O interleaving
> Cygwin: FIFO: improve taking ownership in fifo_reader_thread
> Cygwin: FIFO: fix indentation
> Cygwin: FIFO: make certain errors non-fatal
> Cygwin: FIFO: add missing lock
> Cygwin: fhandler_fifo::take_ownership: don't set event unnecessarily
> Cygwin: FIFO: allow take_ownership to be interrupted
> Cygwin: FIFO: clean up
> Cygwin: FIFO: update commentary
>
> winsup/cygwin/fhandler.h | 55 +--
> winsup/cygwin/fhandler_fifo.cc | 725 ++---
> winsup/cygwin/select.cc| 14 +-
> 3 files changed, 433 insertions(+), 361 deletions(-)
LGTM, please push.
Thanks,
Corinna
--
Corinna Vinschen
Cygwin Maintainer
