Re: [PATCH] tools/nolibc: Add dirfd()

["Thomas Weißschuh" <linux@weissschuh.net>]

On 2026-08-28 20:22:04+0900, Daniel Palmer wrote:
> This is useful for things like fstatat() on children of directory
> opened with opendir().
> 
> At the same time use it to replace the two places that are converting
> the DIR point back into an fd.
> 
> Signed-off-by: Daniel Palmer <daniel@thingy.jp>
> ---
>  tools/include/nolibc/dirent.h | 38 +++++++++++++++++++++++++++--------
>  1 file changed, 30 insertions(+), 8 deletions(-)
> 
> diff --git a/tools/include/nolibc/dirent.h b/tools/include/nolibc/dirent.h
> index 4e02ef25e72d..ba229b215a0b 100644
> --- a/tools/include/nolibc/dirent.h
> +++ b/tools/include/nolibc/dirent.h
> @@ -27,6 +27,18 @@ typedef struct {
>  	char dummy[1];
>  } DIR;
>  
> +/* Internal dirfd() that does not set errno */
> +static __attribute__((unused))
> +int nolibc_dirfd(DIR *dirp)

This pollutes the applications symbol namespace.
It should begin with underscores.
But IMO we could also just keep it inlined in the two users.

> +{
> +	intptr_t i = (intptr_t)dirp;
> +
> +	if (i >= 0)
> +		return -1;
> +
> +	return ~i;
> +}

Could you also add a test for an fdopendir() -> dirfd() roundtrip?


Thomas