[PATCH] fchmodat/fstatat: fix regression with empty `pathname`

[Johannes Schindelin]

Hi Jeremy,

On Wed, 28 Jun 2023, Jeremy Drake wrote:

> On Tue, 27 Jun 2023, Johannes Schindelin wrote:
>
> > In 4b8222983f (Cygwin: fix errno values set by readlinkat, 2023-04-18)
> > the code of `readlinkat()` was adjusted to align the `errno` with Linux'
> > behavior.
> >
> > 	I noticed this issue when one of my workflows failed consistently
> > 	while trying to untar an archive containing a symbolic link and
> > 	claiming this:
> >
> > 		Cannot change mode to rwxr-xr-x: Not a directory
> >
>
> I wonder if this is related to the issue from the thread
> https://cygwin.com/pipermail/cygwin/2023-May/253738.html (sounds like it).

For reference, this is the link I am looking at (because it has superior
thread navigation):
https://inbox.sourceware.org/cygwin/CAJQQdJjUarc1hkZCVX-GWD=Cq7XF4bnWE+ArzLxrUqWWpC7=rg@mail.gmail.com/T/#t

And yes, it looks like it's that very same issue.

> If so, tar was
> rebuilt to pick up the new behavior in 3.4.7 (presumably via configure
> checks), it may need another rebuild to pick up the fixed behavior after
> this fix.

Likely? But then, the patch in question should not _break_ the re-built
`tar`. Or does it?

Ciao,
Johannes