Subject: re: emul/aout, compat/aout [was: Re: Upcoming releases]
To: Bill Studenmund <>
From: Todd Vierling <>
List: tech-userlevel
Date: 12/08/1999 14:05:09
: 	- use the existing compat_aout which has the shadow tree resolution
: 	  problem

I suggested, back around the time this was created, that we rethink how
shadow entries work in the first place.  The reason we get problems with
things like "cd /usr/lib" in a non-native shell is because the shadow
resolution happens for all files _and directories_ on a bunch of file
operation calls.

If the shadow resolution is changed to fiddle only with files that actually
exist, and ignore requests for directories unless lookup in the native
system fails, we'd have a rather less problematic system.  Something like
"mount -o union".

This affects binary emulation of other platforms, not the current a.out
scheme, and has bugged me for *ages*.  (I've brought it up before, some 2-3
years ago now.)


Modifying does not mean removing the current scheme; in fact, all the
problems go away if you don't have an /emul/aout at all.  If we leave it in,
users have a choice of migration paths.

-- Todd Vierling (