Date: Tue, 15 Oct 1996 20:16:41 +0200 (MET DST) From: sos@freebsd.org To: jdp@polstra.com (John Polstra) Cc: msmith@atrad.adelaide.edu.au, hackers@freebsd.org, sos@freebsd.org Subject: Re: Linux compat issue(s) Message-ID: <199610151816.UAA01759@SandBox.CyberCity.dk> In-Reply-To: <199610151643.JAA03974@austin.polstra.com> from "John Polstra" at Oct 15, 96 09:43:33 am
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In reply to John Polstra who wrote:
>
> I still don't agree with Soren:
>
> > ... ELF is
> > only supposed to handle ONE os type per platform, what we are doing
> > is blasfemy (ie not running SVR4).
[stuff deleted]
> The Note section idea also doesn't solve the entire problem. We could
> mark our own FreeBSD ELF files with Note sections, so we could recognize
> them. But unless we could persuade the Linux people to do likewise, we'd
> still be unable to distinguish between Linux ELF files and SVR4 ELF files.
> This is going to be a problem no matter what we do, though.
So, you agree with me after all :)
Its not even enough to distinguish between Linux/FreeBSD (which we could
with note sections) and the rest, we will eventually have to be able to
tell Solaris/DGUX/Olivetti-SVR4/NCR-SVR4/whatnot from each other too,
or we will be in hell anyway. I know for a fact that if we are going
to do SVR4 emulation we will NEED a way to tell them apart. So having
a nice little util that marks the ELF header in ways for us to know
is the ONLY solution to this problem, like it or not.
I propose that we use some unused space in the ELF header. The ELF header
starts with a 16byte char field, where only the first 8 are used in
all the ELF/i386 incarnations I've seen, so we can put a 8 char
text here for the platform (that can easily be seen with the file(1)
cmd too). Simple, easy, nice hack, works....
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
Søren Schmidt (sos@FreeBSD.org) FreeBSD Core Team
Even more code to hack -- will it ever end
..
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