[libcamera-devel] [PATCH 02/14] libcamera: v4l2_device: Overload open() to duplicate File descriptor

[Xavier Roumegue]

Signed-off-by: Xavier Roumegue <xavier.roumegue at oss.nxp.com>
---
 include/libcamera/internal/v4l2_device.h |  2 ++
 src/libcamera/v4l2_device.cpp            | 33 ++++++++++++++++++++++++
 2 files changed, 35 insertions(+)

diff --git a/include/libcamera/internal/v4l2_device.h b/include/libcamera/internal/v4l2_device.h
index 75304be1..8b759311 100644
--- a/include/libcamera/internal/v4l2_device.h
+++ b/include/libcamera/internal/v4l2_device.h
@@ -15,6 +15,7 @@
 #include <linux/videodev2.h>
 
 #include <libcamera/base/log.h>
+#include <libcamera/base/shared_fd.h>
 #include <libcamera/base/signal.h>
 #include <libcamera/base/span.h>
 #include <libcamera/base/unique_fd.h>
@@ -54,6 +55,7 @@ protected:
 	~V4L2Device();
 
 	int open(unsigned int flags);
+	int open(SharedFD handle);
 	int setFd(UniqueFD fd);
 
 	int ioctl(unsigned long request, void *argp);
diff --git a/src/libcamera/v4l2_device.cpp b/src/libcamera/v4l2_device.cpp
index 756188ea..67847bb0 100644
--- a/src/libcamera/v4l2_device.cpp
+++ b/src/libcamera/v4l2_device.cpp
@@ -102,6 +102,39 @@ int V4L2Device::open(unsigned int flags)
 	return 0;
 }
 
+/**
+ * \brief Open a V4L2 device node
+ * \param[in] Shared File descriptor Handle
+ *
+ * Duplicate a shared file descriptor handle and use it for further device
+ * syscalls
+ *
+ * \return 0 on success or a negative error code otherwise
+ */
+int V4L2Device::open(SharedFD handle)
+{
+	int ret;
+
+	UniqueFD newFd = handle.dup();
+	if (!newFd.isValid()) {
+		ret = -errno;
+		LOG(V4L2, Error) << "Failed to duplicate file handle: "
+				 << strerror(-ret);
+		return ret;
+	}
+
+	ret = setFd(std::move(newFd));
+	if (ret < 0) {
+		LOG(V4L2, Error) << "Failed to set file handle: "
+				 << strerror(-ret);
+		return ret;
+	}
+
+	listControls();
+
+	return 0;
+}
+
 /**
  * \brief Set the file descriptor of a V4L2 device
  * \param[in] fd The file descriptor handle
-- 
2.37.3