Messages in this thread | | | From | Peter Waechtler <> | Subject | [PATCH] unified SysV and POSIX mqueues - complete rewrite | Date | Mon, 25 Nov 2002 00:05:00 +0100 |
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[part to lkml] Alan, feel invited to add it to your -ac tree :-)
There are at least 3 attempts to provide POSIX mqueues for Linux:
a) early attempt of Jakub Jelinek based on 2.4-test based on a filesystem with read/write/ioctl interface - very intrusive to ipc/msg.c
b) http://www.mat.uni.torun.pl/~wrona/posix_ipc complicated standalone version (against recent 2.4), with multiplexed syscall - and great effort to keep track of resources which is far easier accomplished by vfs
c) based on a filesystem with its own syscalls and clean separation (but dependence ) on SysV ipc/msg.c why separate syscalls? you cannot specify the priority of a sent message without ioctl/fcntl, also problems with timed versions - and yes there is an outstanding issue with priority aware waitqueues
interface stub and userspace implementation is on http://homepage.mac.com/pwaechtler/linux/mqueue.tgz
The userspace implementation is not complete. There we have the problems with the locks on crashing apps (we could use flock), signal safety but what about the timed versions? Performance is not as good as kernel version!?
following patch is against 2.5.49
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