From fcf98514cb4eb603a05329deec508fe790ba1c17 Mon Sep 17 00:00:00 2001 From: Laurent Pinchart Date: Sun, 28 Nov 2021 19:50:43 +0200 Subject: libcamera: base: file_descriptor: Return UniqueFD from dup() The dup() function returns a duplicate of the file descriptor. Wrapping it in a FileDescriptor isn't wrong as such, but it prevents from using it in contexts where a UniqueFD is needed. As the duplicate is guaranteed to have a single owner when created, return it as a UniqueFD instead. A FileDescriptor can easily be created from the UniqueFD if desired. Signed-off-by: Laurent Pinchart Reviewed-by: Hirokazu Honda Reviewed-by: Jacopo Mondi --- include/libcamera/base/file_descriptor.h | 2 +- src/libcamera/base/file_descriptor.cpp | 22 ++++++++++++++-------- 2 files changed, 15 insertions(+), 9 deletions(-) diff --git a/include/libcamera/base/file_descriptor.h b/include/libcamera/base/file_descriptor.h index 74292eba..12a43f95 100644 --- a/include/libcamera/base/file_descriptor.h +++ b/include/libcamera/base/file_descriptor.h @@ -28,7 +28,7 @@ public: bool isValid() const { return fd_ != nullptr; } int fd() const { return fd_ ? fd_->fd() : -1; } - FileDescriptor dup() const; + UniqueFD dup() const; private: class Descriptor diff --git a/src/libcamera/base/file_descriptor.cpp b/src/libcamera/base/file_descriptor.cpp index da696b25..8e181abc 100644 --- a/src/libcamera/base/file_descriptor.cpp +++ b/src/libcamera/base/file_descriptor.cpp @@ -222,17 +222,23 @@ FileDescriptor &FileDescriptor::operator=(FileDescriptor &&other) * \brief Duplicate a FileDescriptor * * Duplicating a FileDescriptor creates a duplicate of the wrapped file - * descriptor and returns a new FileDescriptor instance that wraps the - * duplicate. The fd() function of the original and duplicate instances will - * return different values. The duplicate instance will not be affected by - * destruction of the original instance or its copies. + * descriptor and returns a UniqueFD that owns the duplicate. The fd() function + * of the original and the get() function of the duplicate will return different + * values. The duplicate instance will not be affected by destruction of the + * original instance or its copies. * - * \return A new FileDescriptor instance wrapping a duplicate of the original - * file descriptor + * \return A UniqueFD owning a duplicate of the original file descriptor */ -FileDescriptor FileDescriptor::dup() const +UniqueFD FileDescriptor::dup() const { - return FileDescriptor(fd()); + UniqueFD dupFd(::dup(fd())); + if (!dupFd.isValid()) { + int ret = -errno; + LOG(FileDescriptor, Error) + << "Failed to dup() fd: " << strerror(-ret); + } + + return dupFd; } FileDescriptor::Descriptor::Descriptor(int fd, bool duplicate) -- cgit v1.2.1