Re: port-xen/50659: Xen4.5 crash with vnds

[Christoph Badura <bad%bsd.de@localhost>]

The following reply was made to PR kern/50659; it has been noted by GNATS.

From: Christoph Badura <bad%bsd.de@localhost>
To: Manuel Bouyer <bouyer%antioche.eu.org@localhost>
Cc: gnats-bugs%netbsd.org@localhost, kern-bug-people%netbsd.org@localhost,
	gnats-admin%netbsd.org@localhost, netbsd-bugs%netbsd.org@localhost,
	sebastian%xenoserver.net@localhost
Subject: Re: port-xen/50659: Xen4.5 crash with vnds
Date: Fri, 25 Mar 2016 14:01:45 +0100

 On Thu, Mar 24, 2016 at 11:35:48PM +0100, Christoph Badura wrote:
 > There's always the option to create an flock package and use the binary
 > from that on old systems.
 
 However, I think we can use a named pipe as a condition variable.
 Something along the following lines:
 
 mkfifo foo.fifo 2>/dev/null
 unlock() { rm foo.lock; exec 4<>foo.fifo; exec 4<&-; }
 lock() {
 	until shlock -f foo.lock -p $$; do
 		exec 4< foo.fifo ; exec 4<&-
 	done
 	exec 4<> foo.fifo; exec 4<&-
 }
 
 zorch() { echo zorch:; cat; }
 
 lock; zorch; unlock
 
 --chris