From kde-core-devel  Sun Apr 01 17:42:03 2007
From: Krzysztof Lichota <krzysiek () lichota ! net>
Date: Sun, 01 Apr 2007 17:42:03 +0000
To: kde-core-devel
Subject: Re: Race condition in KUniqueApplication
Message-Id: <460FEEEB.8030709 () lichota ! net>
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Krzysztof Lichota napisa=C5=82(a):
> While investigating Ark bug I have come across possible race condition
> in KUniqueApplication.
>=20
> It does the following (if --nofork is not set):
> - fork a child
> - child checks if application is running, if not spawns it
> - child reports to parent using pipe if application is running
> - parent sends to application DCOP call to create new instance
> - if DCOP call fails, it just aborts
>=20
> If application is during shutdown (which happens often with Ark when it=

> is unpacking files), the check for application running in child is
> successful, while the DCOP call in parent fails and starting app fails.=

>=20
> IMO the right thing to do would be to make DCOP call in child and repea=
t
> call (and spawning the process) if it fails. This involves many changes=

> in the code, so I tried the other approach: repeat everything in parent=

> process. This works much better (although does not solve Ark bug
> completely, so I have to investigate it further).
> Anyway, the patch (preliminary, it is not intended for applying) is
> attached, what do you think of this whole problem? Have I missed
> something? Should I try to move the DCOP call and loop in child?

Any comments?

	Krzysztof Lichota



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