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Subject: Re: Linux compat issue(s)
To: msmith@atrad.adelaide.edu.au (Michael Smith)
Date: Wed, 16 Oct 1996 13:45:44 +0200 (MET DST)
Cc: sos@FreeBSD.org, msmith@atrad.adelaide.edu.au, jdp@polstra.com,
        hackers@FreeBSD.org
In-Reply-To: <199610161123.UAA03542@genesis.atrad.adelaide.edu.au> from "Michael Smith" at Oct 16, 96 08:53:30 pm
From: sos@FreeBSD.org
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In reply to Michael Smith who wrote:
> 
> sos@FreeBSD.org stands accused of saying:
> > 
> > > Will your changes just reject an unidentifiable ELF binary out-of-hand,
> > > or could you add a sysctl variable to determine which format to 
> > > presume?  The latter method would be best, IMHO.
> > 
> > Hmm, following the ELF style I guess default should always be native, or
> > one could argue for SVR4 compliant (which you dont have yet).
> > I'm not fond of it being variable, that will generate too much support
> > steam I'm afraid.
> 
> Native would be pointless, as native binaries will always be
> identifiable.  The reason I ask is that for the situation where the

NO, wrong, we can't even see if the bin is native !!!!

> Linux emulator had been loaded, but not the (hypothetical) SVR4
> emulator, you could default to Linux and not have to brand your
> binaries, and vice versa.

Hypothetical ?? I have a SVR4 emu :), I just can't/wont't release the code...

> The only situation where branding would be required would be when both
> emulations were active, and IMHO _that_ is likely to generate less
> support steam just by its rarity.
> 
> One could also bias the selection based on the path of the executable,
> as that is visible in exec_elf_imgact.  Anything under /compat/linux
> is likely to be a linux binary, &c &c.  That would further limit the
> requirement for branding to "both emulators loaded and binary outside
> of compatability tree".

I would wote for ALWAYS branding the ELF files, that way there is
NO doubt what sex they are, thus giving least trouble.

> The last ditch "I have no idea, winging it" case could just default to
> the last interpreter in the list - that would let the user alter the
> default if there were more than one available by unloading and
> reloading the LKM.

I'd rather have it give up and say unknown binary format or something like
that, or try running it as a FreeBSD ELF bin.

Now, for a practical question, what should I call the little util ??

markelf, brandelf or just plan elf (fixelf sounds a bit harsh :) )

-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
Soren Schmidt             (sos@FreeBSD.org)             FreeBSD Core Team
               So much code to hack -- so little time.