Hi ALex,
On 5/10/21 9:39 AM, Alejandro Colomar wrote:
> AT_EMPTY_PATH works with empty strings (""), but not with NULL
> (or at least it's not obvious).
>
> The relevant kernel code is the following:
>
> linux$ sed -n 189,198p fs/namei.c
> result->refcnt = 1;
> /* The empty path is special. */
> if (unlikely(!len)) {
> if (empty)
> *empty = 1;
> if (!(flags & LOOKUP_EMPTY)) {
> putname(result);
> return ERR_PTR(-ENOENT);
> }
> }
>
> Reported-by: Walter Harms <wharms@xxxxxx>
> Cc: Theodore Ts'o <tytso@xxxxxxx>
> Cc: Adam Borowski <kilobyte@xxxxxxxxxx>
> Signed-off-by: Alejandro Colomar <alx.manpages@xxxxxxxxx>
Thanks. Patch applied.
Cheers,
Michael
> ---
> man2/open.2 | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/man2/open.2 b/man2/open.2
> index 6360636af..bac1ee806 100644
> --- a/man2/open.2
> +++ b/man2/open.2
> @@ -824,7 +824,7 @@ fd = open("/path/to/dir", O_TMPFILE | O_RDWR,
>
> /* File I/O on \(aqfd\(aq... */
>
> -linkat(fd, NULL, AT_FDCWD, "/path/for/file", AT_EMPTY_PATH);
> +linkat(fd, "", AT_FDCWD, "/path/for/file", AT_EMPTY_PATH);
>
> /* If the caller doesn\(aqt have the CAP_DAC_READ_SEARCH
> capability (needed to use AT_EMPTY_PATH with linkat(2)),
>
--
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/
