Re: [leafnode-list] File locking

[Arne Wichmann <aw@xxxxxxxxxxxxxxx>]

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Also sprach Cornelius Krasel (in <37FC6CD3.BeroList-2.5.9@xxxxxxxxxxxxxxxxx=
uerzburg.de>):
> Lockfiles are used in Leafnode to avoid race conditions with respect
> to the groupinfo file. That is, only one application that modifies
> the groupinfo file can run at a time (i.e. fetch, texpire and applyfilter
> are mutually exclusive).
>=20
> However, if we want to implement local groups there will be a problem,
> because the nntpd itself will have to modify the groupinfo file. It would
> be quite stupid (IMO) if the nntpd would also use the current locking
> mechanism because this would make it impossible to run fetch (or any
> other program) in the background while reading news. Therefore, it would
> be important to come up with a different solution. I have thought quite
> hard about this, but have not come up with a good idea.

As far as I can see, this problem surfaces, when we try to inject news to a
local newsgroup. We might change nntpd so that it locks the groupinfo file,
but only when it wants to read an article. It might even be possible to do
that in a way that batches of articles do not result in mutiple lockings
and unlockings. The other way is to leave nntpd as it is and only create a
small program which is called by cron and feeds the articles. This would
leave nntpd unchanged. The only drawback I can see is that the articles do
not appear directly after they are posted. I do not really mind this.

cu

AW
--=20
Neulich in detebe:
>... und ewig loggt das Weib?

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