[libcamera-devel] [PATCH 1/4] v4l2: compat_manager: Move file operations to new struct FileOperations
Niklas Söderlund
niklas.soderlund at ragnatech.se
Tue Jan 7 18:21:41 CET 2020
Hi Laurent,
Thanks for your patch.
On 2020-01-06 18:14:14 +0200, Laurent Pinchart wrote:
> Create a new FileOperations structure to hold all the dynamically-loaded
> C library file operations. The file operations are now exposed publicly,
> to prepare for usage of mmap in the V4L2CameraProxy.
>
> A new template helper function is added to retrieve a symbol with
> dlsym() with proper casting to simplify the V4L2CompatManager
> constructor.
>
> Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund at ragnatech.se>
> ---
> src/v4l2/v4l2_compat_manager.cpp | 34 ++++++++++++++++++++------------
> src/v4l2/v4l2_compat_manager.h | 34 +++++++++++++++++++-------------
> 2 files changed, 41 insertions(+), 27 deletions(-)
>
> diff --git a/src/v4l2/v4l2_compat_manager.cpp b/src/v4l2/v4l2_compat_manager.cpp
> index a3d693745dd6..fe453445a9fb 100644
> --- a/src/v4l2/v4l2_compat_manager.cpp
> +++ b/src/v4l2/v4l2_compat_manager.cpp
> @@ -28,15 +28,23 @@ using namespace libcamera;
>
> LOG_DEFINE_CATEGORY(V4L2Compat)
>
> +namespace {
> +template<typename T>
> +void get_symbol(T &func, const char *name)
> +{
> + func = reinterpret_cast<T>(dlsym(RTLD_NEXT, name));
> +}
> +} /* namespace */
> +
> V4L2CompatManager::V4L2CompatManager()
> : cm_(nullptr), initialized_(false)
> {
> - openat_func_ = (openat_func_t)dlsym(RTLD_NEXT, "openat");
> - dup_func_ = (dup_func_t )dlsym(RTLD_NEXT, "dup");
> - close_func_ = (close_func_t )dlsym(RTLD_NEXT, "close");
> - ioctl_func_ = (ioctl_func_t )dlsym(RTLD_NEXT, "ioctl");
> - mmap_func_ = (mmap_func_t )dlsym(RTLD_NEXT, "mmap");
> - munmap_func_ = (munmap_func_t)dlsym(RTLD_NEXT, "munmap");
> + get_symbol(fops_.openat, "openat");
> + get_symbol(fops_.dup, "dup");
> + get_symbol(fops_.close, "close");
> + get_symbol(fops_.ioctl, "ioctl");
> + get_symbol(fops_.mmap, "mmap");
> + get_symbol(fops_.munmap, "munmap");
> }
>
> V4L2CompatManager::~V4L2CompatManager()
> @@ -141,7 +149,7 @@ int V4L2CompatManager::getCameraIndex(int fd)
>
> int V4L2CompatManager::openat(int dirfd, const char *path, int oflag, mode_t mode)
> {
> - int fd = openat_func_(dirfd, path, oflag, mode);
> + int fd = fops_.openat(dirfd, path, oflag, mode);
> if (fd < 0)
> return fd;
>
> @@ -160,7 +168,7 @@ int V4L2CompatManager::openat(int dirfd, const char *path, int oflag, mode_t mod
> return fd;
> }
>
> - close_func_(fd);
> + fops_.close(fd);
>
> unsigned int camera_index = static_cast<unsigned int>(ret);
>
> @@ -182,7 +190,7 @@ int V4L2CompatManager::openat(int dirfd, const char *path, int oflag, mode_t mod
>
> int V4L2CompatManager::dup(int oldfd)
> {
> - int newfd = dup_func_(oldfd);
> + int newfd = fops_.dup(oldfd);
> if (newfd < 0)
> return newfd;
>
> @@ -205,7 +213,7 @@ int V4L2CompatManager::close(int fd)
> return 0;
> }
>
> - return close_func_(fd);
> + return fops_.close(fd);
> }
>
> void *V4L2CompatManager::mmap(void *addr, size_t length, int prot, int flags,
> @@ -213,7 +221,7 @@ void *V4L2CompatManager::mmap(void *addr, size_t length, int prot, int flags,
> {
> V4L2CameraProxy *proxy = getProxy(fd);
> if (!proxy)
> - return mmap_func_(addr, length, prot, flags, fd, offset);
> + return fops_.mmap(addr, length, prot, flags, fd, offset);
>
> void *map = proxy->mmap(length, prot, flags, offset);
> if (map == MAP_FAILED)
> @@ -227,7 +235,7 @@ int V4L2CompatManager::munmap(void *addr, size_t length)
> {
> auto device = mmaps_.find(addr);
> if (device == mmaps_.end())
> - return munmap_func_(addr, length);
> + return fops_.munmap(addr, length);
>
> V4L2CameraProxy *proxy = device->second;
>
> @@ -244,7 +252,7 @@ int V4L2CompatManager::ioctl(int fd, unsigned long request, void *arg)
> {
> V4L2CameraProxy *proxy = getProxy(fd);
> if (!proxy)
> - return ioctl_func_(fd, request, arg);
> + return fops_.ioctl(fd, request, arg);
>
> return proxy->ioctl(request, arg);
> }
> diff --git a/src/v4l2/v4l2_compat_manager.h b/src/v4l2/v4l2_compat_manager.h
> index dd9d321078e4..d51b5953d930 100644
> --- a/src/v4l2/v4l2_compat_manager.h
> +++ b/src/v4l2/v4l2_compat_manager.h
> @@ -26,11 +26,30 @@ using namespace libcamera;
> class V4L2CompatManager : public Thread
> {
> public:
> + struct FileOperations {
> + using openat_func_t = int (*)(int dirfd, const char *path,
> + int oflag, ...);
> + using dup_func_t = int (*)(int oldfd);
> + using close_func_t = int (*)(int fd);
> + using ioctl_func_t = int (*)(int fd, unsigned long request, ...);
> + using mmap_func_t = void *(*)(void *addr, size_t length, int prot,
> + int flags, int fd, off_t offset);
> + using munmap_func_t = int (*)(void *addr, size_t length);
> +
> + openat_func_t openat;
> + dup_func_t dup;
> + close_func_t close;
> + ioctl_func_t ioctl;
> + mmap_func_t mmap;
> + munmap_func_t munmap;
> + };
> +
> static V4L2CompatManager *instance();
>
> int init();
>
> V4L2CameraProxy *getProxy(int fd);
> + const FileOperations &fops() const { return fops_; }
>
> int openat(int dirfd, const char *path, int oflag, mode_t mode);
>
> @@ -48,20 +67,7 @@ private:
> void run() override;
> int getCameraIndex(int fd);
>
> - typedef int (*openat_func_t)(int dirfd, const char *path, int oflag, ...);
> - typedef int (*dup_func_t)(int oldfd);
> - typedef int (*close_func_t)(int fd);
> - typedef int (*ioctl_func_t)(int fd, unsigned long request, ...);
> - typedef void *(*mmap_func_t)(void *addr, size_t length, int prot,
> - int flags, int fd, off_t offset);
> - typedef int (*munmap_func_t)(void *addr, size_t length);
> -
> - openat_func_t openat_func_;
> - dup_func_t dup_func_;
> - close_func_t close_func_;
> - ioctl_func_t ioctl_func_;
> - mmap_func_t mmap_func_;
> - munmap_func_t munmap_func_;
> + FileOperations fops_;
>
> CameraManager *cm_;
>
> --
> Regards,
>
> Laurent Pinchart
>
> _______________________________________________
> libcamera-devel mailing list
> libcamera-devel at lists.libcamera.org
> https://lists.libcamera.org/listinfo/libcamera-devel
--
Regards,
Niklas Söderlund
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