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Date: Fri, 21 Aug 2015 18:05:07 +0300
Message-ID: <CAA2C=vA6taarO7vJhQkrqSbozn=KeKhDwh7w1E3bysAC3QJk+g@mail.gmail.com>
Subject: dlopen() failure with ELOOP with legitimate dxe
From: "Ozkan Sezer (sezeroz AT gmail DOT com) [via djgpp AT delorie DOT com]" <djgpp AT delorie DOT com>
To: djgpp <djgpp AT delorie DOT com>
Content-Type: text/plain; charset=UTF-8
Reply-To: djgpp AT delorie DOT com

There is a bug in dlopen() preventing dlopen()ing a dxe.
Here is the scenario, what we experienced with q2dos:

ref_soft.dxe -> has no dependency dxes
ref_gl.dxe -> depends on gl.dxe (present)
gl.dxe -> depends on glide3x.dxe (not present)

Start the exe, dlopen()s ref_soft.dxe -> OK, runs just fine.

Do a dlclose() ref_soft.dxe, and attempt to dlopen() ref_gl.dxe:
fails, no surprise, (dlerror() misleadingly says ENOENT, but ok)

The failure triggers dlopen()ing of ref_soft.dxe again: it fails
with ELOOP which is NOT expected because the dxe is there and it
is legitimate and it loaded and ran successfully the first time.

As far as I can see, the "Load the dependencies" loop around line
237 of dlopen.c does not reset stk_top upon failure which should
be the reason for failure of further dlopen() attempts?

--
O.S.