[systemd-devel] [HEADSUP] /var/lock and /var/lock/lockdev

[Lennart Poettering]

On Mon, 04.04.11 10:56, Ludwig Nussel (ludwig.nussel at suse.de) wrote:

> 
> Lennart Poettering wrote:
> > On Fri, 01.04.11 16:37, Ludwig Nussel (ludwig.nussel at suse.de) wrote:
> > > In any case declaring some directory as the standard place for lock
> > > files doesn't fully solve the problem anyways. The exact lock file
> > > naming isn't quite standardized either. There's at least the FHS
> > > "LCK..name" method and the SVr4 "LK.dev.maj.min" method.
> > 
> > I have never seen LK.x.y.z files. Documentation link?
> 
> http://www.airs.com/ian/uucp-doc/uucp_7.html#SEC86
> http://www.columbia.edu/kermit/ckuins.html#x10
> 
> > It's one thing extending the base that the FHS describes in a distro,
> > it's another thing dropping things that it defines, such as the
> > /var/lock directory.
> > 
> > Now, the only improvement on the brokeness of LCK..xxx style locks we
> > can pull off easily is seperating them from the other stuff that is
> > stored in /var/lock. And this is usually simple (compile time switches
> > in various programs), and actually implemented in Fedora.
> > 
> > I hope this makes some sense.
> 
> So as long as there are no inherently unsolvable problems
> with lockdev using /var/lock directly I see no need to go the a half
> solution /var/lock/lockdev.

There are. A lot of software creates subdirectories beneath
/var/lock, for example LVM. If you allow creation of lockfiles in
/var/lock, then this enables the same programs to break LVM (and
everything else creating subdirs there), and even use LVM to break the
system even further.

That's the point that https://bugzilla.redhat.com/show_bug.cgi?id=581884
tries to make.

> I'd rather add an rpmlint check to ban
> use of /var/lock/subsys on openSUSE, there are only a few packages
> using it anyways.

On Fedora and a lot of other distros /var/lock/subsys is used by the
main RC script to synchronize execution of SysV scripts.

> How many packages in Fedora that did not use lockdev already were
> actually patched to use /var/lock/lockdev anyways?

No idea, this happened before my time.

Lennart

-- 
Lennart Poettering - Red Hat, Inc.