DT_FILTER/DT_AUXILIARY handling in glibc

[Ulrich Drepper]

Jakub Jelinek <jakub@redhat.com> writes:

> On Solaris, on the other side, DT_FILTER puts that library in a
> special search scope (together with its dependencies) and iff a symbol
> is found in the library having the DT_FILTER tag, then search continues in
> the DT_FILTER's library scope,

Yes, this is how it works on Solaris.  I didn't implement it that way
because such an implementation is far too disruptive with not much to
gain.

> DT_AUXILIARY is similar, except a) the library does not have to be
> present b) if the symbol is not found in DT_AUXILIARY's scope, the
> symbol from the library having DT_AUXILIARY tag is returned (ala
> RTLD_SELF).

I'm not sure this description is correct.  This would mean that the
symbol has to exist in the loading DSO.

> Shall I, unless this behaviour difference is desirable, work on a patch?

Iff such a change is made the problem is to get all the boundary cases
(like RTLD_NEXT) and loading/unloading without memory leaks etc right.
And this has to happen without noticable cost since these are clearly
not often used features.

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