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Date: Sun, 17 Jan 2016 18:07:13 +0300
From: Chagin Dmitry <dchagin@freebsd.org>
To: Mateusz Guzik <mjguzik@gmail.com>, Konstantin Belousov <kib@kib.kiev.ua>, 
 Vijay Singh <vijju.singh@gmail.com>, freebsd-hackers@freebsd.org
Subject: Re: irrelevant locking
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On Sun, Jan 17, 2016 at 09:26:42AM +0100, Mateusz Guzik wrote:
> On Sun, Jan 17, 2016 at 11:05:15AM +0300, Chagin Dmitry wrote:
> > On Sun, Jan 17, 2016 at 05:43:15AM +0200, Konstantin Belousov wrote:
> > > On Sat, Jan 16, 2016 at 11:43:13PM +0100, Mateusz Guzik wrote:
> > > > The real question is if it would make sense to add the bit to elf aux
> > > > vector to save the call as done by the loader.
> > > I once did a pass to remove (most of) sysctls executed during process
> > > startup.  issetugid indeed may be treated same.
> > 
> > like a Linux AT_SECURE? our P_SUGID bit can be changed after exec,
> > so the result of issetugid() implementated on auxv table will be unnafected
> > by calls to setuid(), setgid() or other such calls.
> > 
> 
> This is only to save issetugid call done early by the loader and it is
> perfectly safe at that point.
> 
> This definitely is not a replacement for the syscall in general.
>
ah, I understood, thanks.