Re: Environment handling broken in /bin/sh with changes to t,set,put}env()

From: Andrey Chernov <ache_at_nagual.pp.ru>
Date: Sat, 14 Jul 2007 06:26:38 +0400
On Sat, Jul 14, 2007 at 05:43:20AM +0400, Andrey Chernov wrote:
> On Fri, Jul 13, 2007 at 08:10:33PM -0500, Sean C. Farley wrote:
> >> It ends up with environ = NULL; because envVarsTotal initialized to 0
> >> i.e.  makes from "environ[0] == NULL" case "environ == NULL" case
> >> which is different thing.
> > 
> > I changed it to return (0) if either environ or environ[0] equal NULL.
> > The SaveEnviron label is removed as well as the (envVarsTotal > 0)
> > check.
> 
> Looks OK.

BTW, I fear about another place on this matter, merge_environ().
Look at this example:

... some setenv's called before

nenv[0] = NULL;
environ = nenv;
unsetenv("NONEXISTEN");

What happens to environ pointer _after_ that?

unsetenv() leads to environ = watchEnviron; in the merge_environ() but 
this environ is never rebuilded because no single setenv() is called from 
merge_environ() and no rebuild_environ() is called from unsetenv() due to 
"NONEXISTENT" value not found. It means reassigned environ inherits stale 
pointers from non-rebuilded watchEnviron which not equals to 
environ[0] == NULL

Did I miss something?

The same about 

environ = NULL;
unsetenv("NONEXISTEN");

-- 
http://ache.pp.ru/
Received on Sat Jul 14 2007 - 00:26:40 UTC

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