[libcamera-devel] [PATCH] libcamera: base: shared_fd: Don't dup() an invalid fd

[Laurent Pinchart]

The SharedFD::dup() implementation calls the C library dup() function on
the fd. When the SharedFD instance is invalid, this produces an invalid
fd, which is the correct behaviour, but logs an error message.

Fix it by returning an invalid UniqueFD directly when the SharedFD is
invalid. This also saves a system call, which is always nice to do.

Fixes: fcf98514cb4e ("libcamera: base: file_descriptor: Return UniqueFD from dup()")
Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
---
 src/libcamera/base/shared_fd.cpp | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/libcamera/base/shared_fd.cpp b/src/libcamera/base/shared_fd.cpp
index bd2ab5aa25b7..c711cf579a04 100644
--- a/src/libcamera/base/shared_fd.cpp
+++ b/src/libcamera/base/shared_fd.cpp
@@ -253,6 +253,9 @@ SharedFD &SharedFD::operator=(SharedFD &&other)
  */
 UniqueFD SharedFD::dup() const
 {
+	if (!isValid())
+		return {};
+
 	UniqueFD dupFd(::dup(get()));
 	if (!dupFd.isValid()) {
 		int ret = -errno;

base-commit: f8d2f17a3db5ac490d7b505253a98d6795c2b630
-- 
Regards,

Laurent Pinchart