Subject: Re: Removing compat/aout
To: None <tech-kern@netbsd.org>
From: der Mouse <mouse@Rodents.Montreal.QC.CA>
List: tech-kern
Date: 03/10/2002 17:27:22
>> [COMPAT_AOUT path prefixing is thought of] as a generally
>> undesirable side effect.  My point is that those "side effects" can
>> actually be desirable in their own right,
> Can you please name the side effects you are interested in?

Path prefixing, of course - the way /foo/bar gets turned into
/emul/aout/foo/bar.  (The prefix may change when the COMPAT_AOUT name
changes; that's a frill.)  One example of this (and the one that caused
it to go in in the first place, AIUI) is turning /usr/lib into
/emul/aout/usr/lib, for shared libraries.  Another example I've seen
mentioned is shadows for system configuration files in /etc (stuff like
resolv.conf).  I'm sure there are others, like /usr/libexec.

On thinking about it more, what I find desirable is not "path prefixing
for a.out" but really "path prefixing for old binaries", and while the
set of a.out binaries is not identical to the set of binaries old
enough to benefit from path prefixing, the sets are close enough to
equal enough of the time for a.out prefixing to be a useful substitute
for the other.  If you can mutate COMPAT_AOUT into a better mechanism
that addresses the broader need, I'd be all for it - especially if the
result turned out cleaner in the kernel, which I suspect it might.

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