[libcamera-devel] [PATCH] libcamera: camera_sensor: only access V4L_CID_HBLANK if existing

[Alain Volmat]

Correct a crash in CameraSensor::init when trying to set the
V4L2_CID_HBLANK control on sensor not implementing this control.
The HBLANK sensor not being mandatory for non-RAW sensors, it can
happen that the sensor does not expose this control.
Perform check against availability of the control prior to usage in
order to avoid the crash.

Signed-off-by: Alain Volmat <alain.volmat at foss.st.com>
---
 src/libcamera/camera_sensor.cpp | 24 +++++++++++++-----------
 1 file changed, 13 insertions(+), 11 deletions(-)

diff --git a/src/libcamera/camera_sensor.cpp b/src/libcamera/camera_sensor.cpp
index d9261672..0ef78d9c 100644
--- a/src/libcamera/camera_sensor.cpp
+++ b/src/libcamera/camera_sensor.cpp
@@ -197,17 +197,19 @@ int CameraSensor::init()
 	 * \todo The control API ought to have a flag to specify if a control
 	 * is read-only which could be used below.
 	 */
-	const ControlInfo hblank = ctrls.infoMap()->at(V4L2_CID_HBLANK);
-	const int32_t hblankMin = hblank.min().get<int32_t>();
-	const int32_t hblankMax = hblank.max().get<int32_t>();
-
-	if (hblankMin != hblankMax) {
-		ControlList ctrl(subdev_->controls());
-
-		ctrl.set(V4L2_CID_HBLANK, hblankMin);
-		ret = subdev_->setControls(&ctrl);
-		if (ret)
-			return ret;
+	if (ctrls.infoMap()->find(V4L2_CID_HBLANK) != ctrls.infoMap()->end()) {
+		const ControlInfo hblank = ctrls.infoMap()->at(V4L2_CID_HBLANK);
+		const int32_t hblankMin = hblank.min().get<int32_t>();
+		const int32_t hblankMax = hblank.max().get<int32_t>();
+
+		if (hblankMin != hblankMax) {
+			ControlList ctrl(subdev_->controls());
+
+			ctrl.set(V4L2_CID_HBLANK, hblankMin);
+			ret = subdev_->setControls(&ctrl);
+			if (ret)
+				return ret;
+		}
 	}
 
 	return applyTestPatternMode(controls::draft::TestPatternModeEnum::TestPatternModeOff);
-- 
2.25.1