Date: Sat, 14 Jul 2007 10:25:03 -0500 (CDT) From: "Sean C. Farley" <scf@FreeBSD.org> To: Andrey Chernov <ache@nagual.pp.ru> Cc: freebsd-current <freebsd-current@FreeBSD.org> Subject: Re: Environment handling broken in /bin/sh with changes to t,set,put}env() Message-ID: <20070714080553.I27236@thor.farley.org> In-Reply-To: <20070714022638.GA25256@nagual.pp.ru> References: <20070713162742.GA16260@nagual.pp.ru> <20070713142545.K26096@thor.farley.org> <20070713202433.GA19856@nagual.pp.ru> <20070713203915.GA20270@nagual.pp.ru> <20070713171942.Q26096@thor.farley.org> <20070713224608.GB21695@nagual.pp.ru> <20070713184543.A26096@thor.farley.org> <20070714004116.GA22909@nagual.pp.ru> <20070713200048.X26971@thor.farley.org> <20070714014319.GA24701@nagual.pp.ru> <20070714022638.GA25256@nagual.pp.ru>
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On Sat, 14 Jul 2007, Andrey Chernov wrote:
*snip*
> 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?
No. I see it too. Here are the changes:
1. __merge_environ no longer touches environ. Only __rebuild_environ(),
__build_env() and __clean_env() alter environ.
2. watchEnviron renamed to intEnviron.
3. __rebuild_environ() uses intEnviron when cycling through the
environment; it only sets environ.
This way environ is not changed unless it has at least one name-value
pair.
The new patch is here:
http://www.farley.org/freebsd/tmp/setenv/clearenv/patch2
Sean
--
scf@FreeBSD.org
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