From: Ken Brown <kbrown@cornell.edu>
To: cygwin-patches@cygwin.com
Subject: [PATCH 00/12] FIFO: fix multiple reader support
Date: Thu, 16 Jul 2020 12:19:03 -0400 [thread overview]
Message-ID: <20200716161915.16994-1-kbrown@cornell.edu> (raw)
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(-)
--
2.27.0
next reply other threads:[~2020-07-16 16:19 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-16 16:19 Ken Brown [this message]
2020-07-16 16:19 ` [PATCH 01/12] Cygwin: FIFO: fix problems finding new owner Ken Brown
2020-07-16 16:19 ` [PATCH 02/12] Cygwin: FIFO: keep a writer count in shared memory Ken Brown
2020-07-16 16:19 ` [PATCH 03/12] Cygwin: fhandler_fifo::hit_eof: improve reliability Ken Brown
2020-07-16 16:19 ` [PATCH 04/12] Cygwin: FIFO: reduce I/O interleaving Ken Brown
2020-07-16 16:19 ` [PATCH 05/12] Cygwin: FIFO: improve taking ownership in fifo_reader_thread Ken Brown
2020-07-16 16:19 ` [PATCH 06/12] Cygwin: FIFO: fix indentation Ken Brown
2020-07-16 16:19 ` [PATCH 07/12] Cygwin: FIFO: make certain errors non-fatal Ken Brown
2020-07-16 16:19 ` [PATCH 08/12] Cygwin: FIFO: add missing lock Ken Brown
2020-07-16 16:19 ` [PATCH 09/12] Cygwin: fhandler_fifo::take_ownership: don't set event unnecessarily Ken Brown
2020-07-16 16:19 ` [PATCH 10/12] Cygwin: FIFO: allow take_ownership to be interrupted Ken Brown
2020-07-16 16:19 ` [PATCH 11/12] Cygwin: FIFO: clean up Ken Brown
2020-07-16 16:19 ` [PATCH 12/12] Cygwin: FIFO: update commentary Ken Brown
2020-07-16 19:57 ` [PATCH 00/12] FIFO: fix multiple reader support Corinna Vinschen
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