[buildd-tools-devel] Bug#718127: Bug#718127: schroot: CHROOT_SESSION_PURGE and tar-based source chroots

[Roger Leigh]

On Thu, Jul 10, 2014 at 11:03:38PM +0200, Aurelien Jarno wrote:
> On Thu, Jul 10, 2014 at 09:07:57PM +0100, Roger Leigh wrote:
> 
> > I think the correct solution will be to add a
> > 
> >   CHROOT_SESSION_SOURCE=true|false
> > 
> > setup environment variable, with corresponding
> > 
> >   SESSION_SOURCE  = 1 << 3  ///< The chroot is a source chroot.
> > 
> > setup flag to be set by the chroot facets.  The reason for this is that
> > SESSION_PURGE is indicating that the session will be purged, and
> > nothing more than that.  It does not make any implied statement about
> > whether or not it's a source chroot or not.  For most chroot types,
> > this is only set for non-source chroots since it uses a different
> > chroot type for the source chroot, but this isn't the case for file
> > chroots where both the source and non-source chroots are both
> > purged.  I'd rather not overload this flag with unwarranted meaning,
> > so I think adding an additional flag is the way to go here.
> > 
> 
> That's looks quite reasonable to me.

To implement this, we need session and source facets to have a
pointer to the parent chroot.  So we query a session chroot
and ask if its parent was a source chroot, and also link from
a source chroot to plain chroot for generality and
completeness.  Initial scoping for 1.7 (1.6 will be backported):

- chroot to inherit enable_shared_from_this and/or switch to
  using weak_ptr rather than bare pointers for the facet->chroot
  back reference
- session and source need "shared_ptr<chroot> parent" fields
- session::create and source::create constructors to take a
  "shared_ptr<chroot> parent" argument.  This will be passed by
  session_clonable::clone_session and source_clonable::clone_source,
  respectively
- session can check for the presence of a source facet in its
  parent and set SESSION_SOURCE if parent is not null and the
  facet is present.
- chroot will set CHROOT_SESSION_SOURCE=true if the SESSION_SOURCE
  flag is set, otherwise set to false.


Regards,
Roger

-- 
  .''`.  Roger Leigh
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