[libvirt] [PATCH v2 1/2] vbox: change how vbox API is initialized.

[Dawid Zamirski]

On Wed, 2016-11-23 at 11:00 -0500, Dawid Zamirski wrote:
> On Wed, 2016-11-23 at 08:55 -0500, John Ferlan wrote:
> > [...]
> > > +
> > > +static vboxDriverPtr
> > > +vboxGetDriverConnection(void)
> > > +{
> > > +    virMutexLock(&vbox_driver_lock);
> > > +
> > > +    if (vbox_driver) {
> > > +        virObjectRef(vbox_driver);
> > > +    } else {
> > > +        vbox_driver = vboxDriverObjNew();
> > > +
> > > +        if (!vbox_driver) {
> > > +            virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
> > > +                           _("Failed to create vbox driver
> > > object."));
> > > +            return NULL;
> > > +        }
> > > +    }
> > > +
> > > +    if (vboxSdkInitialize() < 0 || vboxExtractVersion() < 0) {
> > 
> > In this path should vboxSdkUninitialize be called (since it
> > wouldn't
> > be
> > called in the destroy path)?
> 
> If vboxSdkUnintialize fails, VBoxSVC is not started so it does not
> need
> to be unintialized - which is in line with the sample code included
> SDK
> where it returns with EXIT_FAILUE in main if pfnClientInifialize
> fails.
> However, if vboxExtractVersion fails (unlikely) we might want to call
> gVBoxAPI.UPFN.Unintialize(vbox_driver) directly (not via
> vboxSdkUninitialize as it checks connectionCount > 0 which on failure
> would be 0). I've just tested both cases with
> gVBoxAPI.UPFN.Unintialize
> in the failure path, and calling it does not do any harm in both
> cases,
> so I guess it would be a good idea to put it there.
> 

Actually, I was wrong in that it's safe to call
gVBoxAPI.UPFN.Unintialize when vboxSdkInitialize fails - I got segfault
when attempting to connect twice in VBOX_RELEASE(data->vboxObject).
It's safe to do this though:

    if (vboxSdkInitialize() < 0) {
        virObjectUnref(vbox_driver);
        virMutexUnlock(&vbox_driver_lock);

        return NULL;
    }

    if (vboxExtractVersion() < 0) {
        gVBoxAPI.UPFN.Uninitialize(vbox_driver);
        virObjectUnref(vbox_driver);
        virMutexUnlock(&vbox_driver_lock);

        return NULL;
    }
 
i.e do not uninitalize on initialize failure, but do unintialize on
vboxExractVersion failure.