Date: Mon, 22 Apr 1996 22:03:41 -0400 (EDT) From: Sujal Patel <smpatel@umiacs.umd.edu> To: John Polstra <jdp@polstra.com> Cc: current@freebsd.org Subject: Re: possible 4th option? [Re: kern/1102] Message-ID: <Pine.NEB.3.92.960422220113.205J-100000@xi.dorm.umd.edu> In-Reply-To: <199604230135.SAA03252@austin.polstra.com>
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On Mon, 22 Apr 1996, John Polstra wrote: > They're not unused -- they're _reserved_. If you stick anything other > than 0 in them, you're technically no longer producing a valid ELF file. > The analogous objection applies also to other ELF header fields such as > e_type, e_machine, and e_flags. > > This may seem like a minor nit, but it's not. Suppose somebody else, > say Sun, also decides to identify their executables using the extra > bytes of the e_ident tag. Suppose their choice of values collides with > yours. Too bad, you're out of luck. You are absolutely correct here. Unless it's in the standard, it's a hack. > I'm going to try to add this kind of identification to our FreeBSD ELF > executables, and fix the kernel to recognize them. (Unfortunately, as > usual, the binutils code maze is doing its best to make this difficult > for me.) I'd like to coordinate this with the Linux people, if they're > interested. If you can coordinate with the Linux people, then I think this would be worthwhile; otherwise we may be the only ones using this technique. I still think that we will need a method for the user to specify EXACTLY what type of binary we're dealing with (for those "slip through the crack" cases). I think that a variation of my original patch (moving all environment parsing to libc), would work very well for this. Sujal
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