[libcamera-devel] [RFC/PATCH 1/5] qcam: Check that camera can generate configuration from roles

[Niklas Söderlund]

Hi Laurent,

Thanks for your feedback.

On 2020-04-30 03:44:14 +0300, Laurent Pinchart wrote:
> Hi Niklas,
> 
> Thank you for the patch.
> 
> On Thu, Apr 30, 2020 at 02:36:00AM +0200, Niklas Söderlund wrote:
> > If the camera can not generate a configuration from the requested roles
> > it returns a nullptr which leads to a nullptr dereference. Fix this by
> > adding a check that the camera generated a configuration before trying
> > to access it.
> > 
> > Signed-off-by: Niklas Söderlund <niklas.soderlund at ragnatech.se>
> > ---
> >  src/qcam/main_window.cpp | 4 ++++
> >  1 file changed, 4 insertions(+)
> > 
> > diff --git a/src/qcam/main_window.cpp b/src/qcam/main_window.cpp
> > index ee779728fc630da8..b683c2e00d317307 100644
> > --- a/src/qcam/main_window.cpp
> > +++ b/src/qcam/main_window.cpp
> > @@ -293,6 +293,10 @@ int MainWindow::startCapture()
> >  
> >  	/* Configure the camera. */
> >  	config_ = camera_->generateConfiguration(roles);
> > +	if (!config_) {
> > +		qWarning() << "Failed to generate configuration from roles";
> > +		return -EINVAL;
> > +	}
> 
> This is certainly better than a crash, so
> 
> Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> 
> but what happens in the GUI ?

It refuses to start to stream but does not lock-up, same as for the 
error cases bellow this one where -EINVAL is already returned.

> 
> >  
> >  	StreamConfiguration &cfg = config_->at(0);
> >  
> 
> -- 
> Regards,
> 
> Laurent Pinchart

-- 
Regards,
Niklas Söderlund