[PATCH 06/10] v4l2: v4l2_compat: Selectively disable -Wmissing-declarations

[Kieran Bingham]

Quoting Laurent Pinchart (2024-06-24 20:29:37)
> _FORTIFY_SOURCE redirects the open*() calls to __open*_2() functions.
> The libcamera V4L2 adaptation layer intercepts those functions to
> support applications compiled with _FORTIFY_SOURCE. When _FORTIFY_SOURCE
> is not enabled, the C library headers will not provide declarations for
> the fortified functions, which will cause missing declaration warnings
> when we unable them.
> 
> Fix this by disabling the -Wmissing-declarations warnings selectively
> for the _FORTIFY_SOURCE functions. To avoid sparkling pragmas around,
> move the relevant function definitions next to each other.

Looks reasonable to keep the fortified versions together. One of either
you or Barnabás will need to rebase though...


Reviewed-by: Kieran Bingham <kieran.bingham at ideasonboard.com>

> 
> Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> ---
>  src/v4l2/v4l2_compat.cpp | 43 ++++++++++++++++++++++++----------------
>  1 file changed, 26 insertions(+), 17 deletions(-)
> 
> diff --git a/src/v4l2/v4l2_compat.cpp b/src/v4l2/v4l2_compat.cpp
> index 9dd1577dfbde..8ff93192c3e3 100644
> --- a/src/v4l2/v4l2_compat.cpp
> +++ b/src/v4l2/v4l2_compat.cpp
> @@ -42,12 +42,6 @@ LIBCAMERA_PUBLIC int open(const char *path, int oflag, ...)
>                                                      oflag, mode);
>  }
>  
> -/* _FORTIFY_SOURCE redirects open to __open_2 */
> -LIBCAMERA_PUBLIC int __open_2(const char *path, int oflag)
> -{
> -       return open(path, oflag);
> -}
> -
>  #ifndef open64
>  LIBCAMERA_PUBLIC int open64(const char *path, int oflag, ...)
>  {
> @@ -58,11 +52,6 @@ LIBCAMERA_PUBLIC int open64(const char *path, int oflag, ...)
>         return V4L2CompatManager::instance()->openat(AT_FDCWD, path,
>                                                      oflag | O_LARGEFILE, mode);
>  }
> -
> -LIBCAMERA_PUBLIC int __open64_2(const char *path, int oflag)
> -{
> -       return open(path, oflag);
> -}
>  #endif
>  
>  LIBCAMERA_PUBLIC int openat(int dirfd, const char *path, int oflag, ...)
> @@ -74,11 +63,6 @@ LIBCAMERA_PUBLIC int openat(int dirfd, const char *path, int oflag, ...)
>         return V4L2CompatManager::instance()->openat(dirfd, path, oflag, mode);
>  }
>  
> -LIBCAMERA_PUBLIC int __openat_2(int dirfd, const char *path, int oflag)
> -{
> -       return openat(dirfd, path, oflag);
> -}
> -
>  #ifndef openat64
>  LIBCAMERA_PUBLIC int openat64(int dirfd, const char *path, int oflag, ...)
>  {
> @@ -89,12 +73,37 @@ LIBCAMERA_PUBLIC int openat64(int dirfd, const char *path, int oflag, ...)
>         return V4L2CompatManager::instance()->openat(dirfd, path,
>                                                      oflag | O_LARGEFILE, mode);
>  }
> +#endif
> +
> +/*
> + * _FORTIFY_SOURCE redirects open* to __open*_2. Disable the
> + * -Wmissing-declarations warnings, as the functions won't be declared if
> + *  _FORTIFY_SOURCE is not in use.
> + */
> +#pragma GCC diagnostic push
> +#pragma GCC diagnostic ignored "-Wmissing-declarations"
> +
> +LIBCAMERA_PUBLIC int __open_2(const char *path, int oflag)
> +{
> +       return open(path, oflag);
> +}
> +
> +LIBCAMERA_PUBLIC int __open64_2(const char *path, int oflag)
> +{
> +       return open(path, oflag);
> +}
> +
> +LIBCAMERA_PUBLIC int __openat_2(int dirfd, const char *path, int oflag)
> +{
> +       return openat(dirfd, path, oflag);
> +}
>  
>  LIBCAMERA_PUBLIC int __openat64_2(int dirfd, const char *path, int oflag)
>  {
>         return openat(dirfd, path, oflag);
>  }
> -#endif
> +
> +#pragma GCC diagnostic pop
>  
>  LIBCAMERA_PUBLIC int dup(int oldfd)
>  {
> -- 
> Regards,
> 
> Laurent Pinchart
>