Re: incorrect use of pidfile(3)
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On Thu, Oct 13, 2011 at 12:54:38PM +0200, Dag-Erling Sm=F8rgrav wrote:
> I looked at some of the programs that use pidfile(3) in base, and they
> pretty much all get it wrong. Consider these two scenarios:
>=20
> 1) common case
>=20
> process A process B
>=20
> main()
> pidfile_open() -> success
> perform_initialization()
> daemon()
> pidfile_write() -> success
> perform_work() main()
> pidfile_open() -> EEXIST
> exit()
>=20
> 2) very unlikely but still possible case
>=20
> process A process B
>=20
> main()
> pidfile_open() -> success main()
> perform_initialization() pidfile_open() -> EAGAIN
> daemon() perform_initialization()
> pidfile_write() -> success daemon()
> perform_work() perform_work()
>=20
> The problem is that most of them (at least the ones I checked) ignore a
> pidfile_open() failure unless errno =3D=3D EEXIST.
>=20
> How do we fix this? My suggestion is to loop until pidfile_open()
> succeeds or errno !=3D EAGAIN. Does anyone have any objections to that
> approach?
I think we already do that internally in pidfile_open(). Can you take a loo=
k at
the source and confirm that this is what you mean?
--=20
Pawel Jakub Dawidek http://www.wheelsystems.com
FreeBSD committer http://www.FreeBSD.org
Am I Evil? Yes, I Am! http://yomoli.com
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