[libcamera-devel] [PATCH] libcamera: camera: Ensure requests belong to the camera

[Laurent Pinchart]

On Mon, Apr 11, 2022 at 03:02:07PM +0530, Umang Jain via libcamera-devel wrote:
> Hi Kieran,
> 
> On 4/11/22 01:54, Kieran Bingham via libcamera-devel wrote:
> > Quoting Kieran Bingham (2022-03-17 13:17:26)
> >> Requests are created by a Camera, and can only be queued
> >> to that specific Camera. Enforce this during the public API
> >> to prevent mis-use by incorrect applications.
> >>
> >> Signed-off-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
> >> ---
> >>   src/libcamera/camera.cpp | 7 +++++++
> >>   1 file changed, 7 insertions(+)
> >>
> >> diff --git a/src/libcamera/camera.cpp b/src/libcamera/camera.cpp
> >> index bb856d606f4a..dd6552e83eee 100644
> >> --- a/src/libcamera/camera.cpp
> >> +++ b/src/libcamera/camera.cpp
> >> @@ -23,6 +23,7 @@
> >>   #include "libcamera/internal/camera_controls.h"
> >>   #include "libcamera/internal/formats.h"
> >>   #include "libcamera/internal/pipeline_handler.h"
> >> +#include "libcamera/internal/request.h"
> >>   
> >>   /**
> >>    * \file libcamera/camera.h
> >> @@ -1119,6 +1120,12 @@ int Camera::queueRequest(Request *request)
> >>          if (ret < 0)
> >>                  return ret;
> >>   
> >> +       /* Requests can only be queued to the camera that created them.*/
> >> +       if (request->_d()->camera() != this) {
> >> +               LOG(Camera, Error) << "Request was not created by this camera";
> >> +               return -EINVAL;
> > I have two tags so I'm ready to merge this but ...  I'm tempted to make
> > this a distinct return code:
> >
> >    EXDEV 18 Invalid cross-device link
> >
> > Adding
> > + * \retval -EXDEV The request does not belong to this camera
> >
> > to the doxygen accordingly.
> >
> > Any comments, either a +1 or a -1 on whether I should or should not post
> > a v2 with this?
> 
> 
> -1 (i.e. shouldn't need a v2 on the list).
> 
> I am okay returning with EXDEV as the error code.

Agreed, -EXDEV looks good to me too.

> >> +       }
> >> +
> >>          /*
> >>           * The camera state may change until the end of the function. No locking
> >>           * is however needed as PipelineHandler::queueRequest() will handle

-- 
Regards,

Laurent Pinchart