Re: A possible libc/dlmopen/pthreads bug

[Vivek Das Mohapatra <vivek at collabora dot com>]

> This concept of "shim" libraries will only work for some
> limited set of libraries that are relatively stateless
> (and as you see glibc is not).

In my use case the shim library arranges for there to be only one
copy of the library being shimmed - the main namespace "thinks"
it has a copy of the library, but there's actually no code there,
only enough ELF data that it thinks linking can work: Since there's
only one copy even stateful libraries work (but see later).

The shim makes sure the same function pointers are used both inside
and outside the namespace *for the target library only*, not any
further dependencies.

*However* for the libc cluster we really do want there to be only one
copy, since shimming cannot occur until _after_ libc has been mapped
(since libc is pretty fundamental).

I'll see if I can understand the dl[m]open worker code well enough to
provide a patch.