bug#12632: file permissions checking mishandled when setuid

[Eli Zaretskii]

> Date: Sun, 14 Oct 2012 13:40:52 -0700
> From: Paul Eggert <eggert@cs.ucla.edu>
> CC: 12632@debbugs.gnu.org
> 
> On 10/14/2012 01:17 PM, Eli Zaretskii wrote:
> > If euidaccess always agrees with stat, why does it make sense to
> > switch check_existing to using euidaccess
> 
> euidaccess always agrees with 'stat' with respect to access checks,
> but there are other reasons that 'stat' could fail, e.g.,
> on a file that is too large for 'stat' to represent the size.

That sounds like a very weak reason to switch to a non-portable API,
especially since Emacs will be unable to do anything with such
imaginary files anyway.  And gnulib's euidaccess will also fail for
them in most non-trivial cases, because it calls stat.