[PATCH v1] v4l2: v4l2_compat: Fix redirect from `__open(at)64_2()`

[Kieran Bingham]

Quoting Barnabás Pőcze (2024-06-17 22:43:45)
> `__open64_2()` and `__openat64_2()` should redirect
> to `open64()` and `openat64()`, respectively, otherwise
> the `O_LARGEFILE` flag will not be applied.
> 
> Fixes: 1023107b6405 ("v4l2: v4l2_compat: Intercept open64, openat64, and mmap64")
> Signed-off-by: Barnabás Pőcze <pobrn at protonmail.com>

CI is all green here.
https://gitlab.freedesktop.org/camera/libcamera/-/pipelines/1203630 

But commit 1023107b6405 ("v4l2: v4l2_compat: Intercept open64, openat64, and mmap64")
states:

    Also, since we set _FILE_OFFSET_BITS to 32 to force the various open and
    mmap symbols that we export to not be the 64-bit versions, our dlsym to
    get the original open and mmap calls will not automatically be converted
    to their 64-bit versions. Since we intercept both 32-bit and 64-bit
    versions of open and mmap, we should be using the 64-bit version to
    service both. Fetch the 64-bit versions of openat and mmap directly.

is that why these were the non-64 bit variants?

This feels like it's "too obvious" ... I wonder what we missed ...

Paul? Any insights? (It was ... a long time ago that you wrote that
patch)



> ---
>  src/v4l2/v4l2_compat.cpp | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/src/v4l2/v4l2_compat.cpp b/src/v4l2/v4l2_compat.cpp
> index 8e2b7e92..8a44403e 100644
> --- a/src/v4l2/v4l2_compat.cpp
> +++ b/src/v4l2/v4l2_compat.cpp
> @@ -59,7 +59,7 @@ LIBCAMERA_PUBLIC int open64(const char *path, int oflag, ...)
>  
>  LIBCAMERA_PUBLIC int __open64_2(const char *path, int oflag)
>  {
> -       return open(path, oflag);
> +       return open64(path, oflag);
>  }
>  #endif
>  
> @@ -90,7 +90,7 @@ LIBCAMERA_PUBLIC int openat64(int dirfd, const char *path, int oflag, ...)
>  
>  LIBCAMERA_PUBLIC int __openat64_2(int dirfd, const char *path, int oflag)
>  {
> -       return openat(dirfd, path, oflag);
> +       return openat64(dirfd, path, oflag);
>  }
>  #endif
>  
> -- 
> 2.45.2
> 
>