Re: euidaccess() as syscall

["Oleg Verych" <olecom@gmail.com>]

Matthew Wilcox @ Fri, May 2, 2008 at 6:06 PM:
> On Fri, May 02, 2008 at 05:59:36PM +0100, Oleg Verych wrote:
>  > Hallo.
>  >
>  > Why there's no euidaccess() syscall (most obvious use is in `test` or
>  > `[` utility)?
>  >
>  > Instead euiaccess() in glibc and access() in kernel are doing unnecessary uid
>  > shuffling.
>
>  Are there any programs which care?  Do you have a benchmark that might
>  show an improvement if we added an euidaccess() syscall?
>
>  My impression was that most programs ignore the access() family of
>  syscalls and just try to do the open and cope with the failure.  They
>  have to anyway, since the file could have changed permission between the
>  call to access() and the call to open().

open() will change timestamp. `bash` and `dash` have very broken workarounds of
access() in `test` due to euid requirements. I.e. read-only fs for
root or various
selinux-like restrictions are not shown unless open() is used.

So, it's better just to use stat64(), right?
____