.init/.fini section question

["Darryl L. Miles" <darryl-mailinglists at netbauds dot net>]

Hi,

First where is the best source of documentation over ELF features that 
can be used by DSOs ?

I'd like to confirm some points:


* The dynamic linker serializes all invocations to an individual DSOs 
.init/.fini pointers (clarification covered in next 3 points).

  * That protection is provided between pointers of a single DSOs, i.e. 
they are fired in order of the ELF section synchronously.

  * That protection is provided between two (or more) independent 
threads causing the same DSO to be loaded.  i.e. the dynamic linker 
provides a mutex around the loading procedure and each user that is 
increasing the reference count gets to do their thing in turns.

  * This results in the .init/.fini pointers conforming to a 
single-threaded model (which is being enforced by the dynamic linker, 
even if the outside world is a multi-threaded enviroment).


* That each loading the DSO fires the .init/.fini, meaning each time 
the reference count inside the dynamic linker increments we always get 
the callbacks fired (for example through dlopen()).

* Does the .init/.fini method have a way of asking the dynamic linker 
for its own handle/reference and what information does the dynamic 
linker make available through that.



Thanks,

Darryl