Bug#43651: ACCEPTED] mailbox locking
On Mon, 25 Oct 1999, Julian Gilbey wrote:
> I am about to include this amendment in policy. However, I am stuck
> with the wording, as you say the following.
>
> Questions: What version number should be used in footnote 2?
> What do we do with the reference implementation?
Good question. I didn't hear from Miquel van Smoorenburg (the
maintainer of liblockfile) since 1999-09-21. In his last mail he
thought about different way how to implement the changed the behavior
in liblockfile (by completely changing the API or by leaving the
fcntl() part to the calling program).
> > So I think we should change the above paragraph to something which
> > explicitly says, how locking has to be implemented:
> >
> > All Debian MUAs, MTAs, MDAs and other mailbox accessing programs
> > (like IMAP daemons) have to lock the mailbox in a NFS-safe way.
> > This means that fcntl() locking has to be combined with dot
> > locking. To avoid dead locks, a program has to use fcntl() first
> > and dot locking after this or alternatively implement the two
> > locking methods in a non blocking way[1]. Using the functions
> > `maillock' and `mailunlock' provided by the `liblockfile*'[2]
> > packages is the recommended way to realize this.
> >
> > Footnotes:
> > [1] If it is not possible to establish both locks, the system
> > shouldn't wait for the second lock to be established, but
> > remove the first lock, wait a (random) time, and start over
> > locking again.
> > [2] liblockfile version >= .... (fill in a version number here,
> > which implements the above noted non blocking mechanism
> > without blocking).
Maybe we should say "liblockfile version >> 1.01" until there is no
new version available yet?
Miquel, what are you thinking about this?
Ciao
Roland
--
* roland@spinnaker.de * http://www.spinnaker.de/ *
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