Cygwin >= 1.7.6 open message queues - permission denied

Manuel Wienand Manuel.Wienand@ubitronix.com
Wed Oct 6 08:16:00 GMT 2010


Hi,

I noticed that I get a permission denied error when I try to open a message queue in the same process or
in an other process.
The problem can be reproduced using the code given at: http://sourceware.org/ml/cygwin/2009-09/msg00629.html
I tried several versions:
1.7.7 (from the installer): permission denied
1.7.6 (0.230/5/3 2010-08-16 16:06, downgraded using the installer) : permission denied
1.7.5 (0.225/5/3 2010-04-12 19:07, extracted cygwin-1.7.5-1.tar.bz2 from one of the mirrors): mqueue works.

Another thing I noticed is that the execute permission won't be set for the owner of the message queue file.
E.g. in mq_open I set (S_IRWXU | S_IRWXG | S_IRWXO), but when looking at the created file in the cygwin shell
(located in /dev/mqueue/) the permissions are set to "-rw-rwxrwx". But it doesn't seem to have any impact on
the permission denied problem, since the execute permission isn't set in any of the tested versions.

Regards,

Manuel


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