Re: [gentoo-dev] eclass for handling of file-based capabilities

[Michał Górny]

On Sun, 6 Mar 2011 17:34:29 +0100
Constanze Hausner <constanze@g.o> wrote:

> On 17:44 Sat 05 Mar     , Ciaran McCreesh wrote:
> > * some filesystems don't support xattrs at all, and the package
> > manager needs to support installing to them, even if the user is
> > building on a filesystem that does support it
>
> While GSoC I was not able to come up with a good fallback mechanism.
> I'm going to give the new ideas some thought over the week and
> hopefully come up with something good :).

How about that:
1) src_install() installs a file, like in:
	/var/lib/gentoo/filecaps.d/${PF}
specifying which caps have to applied to which files,

2) the eclass depends on an ebuild, installing a kind
of 'filecaps-apply' tool, reading information from that file and trying
to apply filecaps as necessary (and flipping setuid bits),

3) the eclass calls that tool in pkg_postinst() to apply the caps
on the target filesystem.

This should help with all the issues mentioned, including binpkg
support. Moreover, user could use the tool manually to restore/reset
filecaps if they were lost or unapplied (e.g. due to incorrect kernel
config).

-- 
Best regards,
Michał Górny