[Libvir] PATCH: Fix xen unified driver open logic

[Daniel Veillard]

On Mon, Mar 17, 2008 at 04:02:06PM +0000, Daniel P. Berrange wrote:
> On Tue, Mar 11, 2008 at 06:47:47AM -0400, Daniel Veillard wrote:
> > On Mon, Mar 10, 2008 at 07:09:36PM +0000, Daniel P. Berrange wrote:
> > > When adding PolicyKit support we disabled the proxy driver, but did not
> > > correctly fix up the Xen unified driver. The result is that it is still
> > > trying to run the proxy setuid helper which doesn't exist and thus it fails
> > > the open operation before the remote driver gets the opportunity to process
> > > the URI. I attempted to fix this by just disabling the proxy driver in the
> > > unified driver, but came to the conclusion the logic of the current code is
> > > just not flexible enough for what we need to be able todo  these days.
> > > 
> > > THe core problem is the 'for(;;)' loop iterating over the drivers - it
> > > already has several special cases in the loop body to skip drivers, or
> > > ignore errors and adding more special cases is making my mind hurt trying
> > > to trace the logic.
> > > 
> > > So I have removed the loop, and encode the desired logic explicitly. The
> > > diff a little unpleasant to read, so to summarize the logic is thus:
> > > 
> > >  - If root only, try open the hypervisor driver
> > >          -> Failure to open is fatal, do not try other drivers
> > 
> >   hum, I'm not 100% sure of that, an old libvirt version might still be
> > able to work though xend in face of an hypervisor change it can't handle,
> > we had the problem for example with 0.4.0 on xen-3.2, there was side effects
> > but it was basically working without hypervisor access...
> 
> This attached patch adds that use case too. Failure of the HV driver is
> now non-fatal. The other rules below are unchagned

  Okidoc, +1 :-)

    thanks !

Daniel

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