[libcamera-devel] [PATCH] v4l2: v4l2_camera_proxy, v4l2_camera: Check return values of read/write

[Paul Elder]

The return value of the write to the eventfd (to signal POLLIN) from
V4L2Camera and the read from the eventfd (to clear POLLIN) from
V4L2CameraProxy was not ignored. Check the return value, and print an
error message.

Reported-by: Coverity CID=290743
Reported-by: Coverity CID=290744
Signed-off-by: Paul Elder <paul.elder at ideasonboard.com>
---
 src/v4l2/v4l2_camera.cpp       | 4 +++-
 src/v4l2/v4l2_camera_proxy.cpp | 4 +++-
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/v4l2/v4l2_camera.cpp b/src/v4l2/v4l2_camera.cpp
index 3c36932..9a1ebc8 100644
--- a/src/v4l2/v4l2_camera.cpp
+++ b/src/v4l2/v4l2_camera.cpp
@@ -91,7 +91,9 @@ void V4L2Camera::requestComplete(Request *request)
 	bufferLock_.unlock();
 
 	uint64_t data = 1;
-	::write(efd_, &data, sizeof(data));
+	int ret = ::write(efd_, &data, sizeof(data));
+	if (ret != sizeof(data))
+		LOG(V4L2Compat, Error) << "Failed to signal eventfd POLLIN";
 
 	bufferSema_.release();
 }
diff --git a/src/v4l2/v4l2_camera_proxy.cpp b/src/v4l2/v4l2_camera_proxy.cpp
index 308a8ab..17477ab 100644
--- a/src/v4l2/v4l2_camera_proxy.cpp
+++ b/src/v4l2/v4l2_camera_proxy.cpp
@@ -454,7 +454,9 @@ int V4L2CameraProxy::vidioc_dqbuf(struct v4l2_buffer *arg)
 	currentBuf_ = (currentBuf_ + 1) % bufferCount_;
 
 	uint64_t data;
-	::read(efd_, &data, sizeof(data));
+	ret = ::read(efd_, &data, sizeof(data));
+	if (ret != sizeof(data))
+		LOG(V4L2Compat, Error) << "Failed to clear eventfd POLLIN";
 
 	return 0;
 }
-- 
2.27.0