lt_dllopenext() returns invalid handle (was: 1.1.2 is broken if you have closefrom() )

Alan DeKok aland at
Fri Jun 16 02:18:11 CEST 2006

Frank Cusack <fcusack at> wrote:
> Apparently, it CAN happen that handle is not NULL, but I have to assume
> that this line of code doesn't think that can happen. (Because of course,
> it is a pretty bad idea to return a non-NULL handle on failure, and ltdl
> is obviously not written by idiots.)

  Intelligent is not the same as competent.

  In this case, if (errors > 0), they should return NULL.  That
results in a memory leak if "handle" wasn't freed, but correct code.
As it stands now, they have no *requirement* in that function that it
returns NULL on error.  It's just an accidental side effect of them
sometimes freeing handle.

> You can't just read this one line of code and say "handle is returned!",
> you have to look at what is expected from try_dlopen().

  Yes.  I've looked at the code, and have no idea what it's doing or

  In any case, I think I'm going to run some analysis on it in the
next few weeks, so I should have results as to what execution path
causes the problem, and why.

> Bah.  I didn't realize lt_dlhandle was opaque (because how does gdb know
> what it looks like).  phooey.  OK, we'll need to patch ltdl.c, but
> otherwise (ie autoconf stuff) we can still get away with untouched original
> source.


  Alan DeKok.

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