Re: [Qemu-devel] [PATCH v10 5/8] module: implement module loading

[Fam Zheng]

On Mon, 09/16 13:33, Paolo Bonzini wrote:
> Il 16/09/2013 13:29, Fam Zheng ha scritto:
> > An idea for single .so file:
> >     - before loads a .so, an empty initializer list is created.
> >     - module_init adds a __attribute__((constructor)) function, which 
> > appends
> >       its real initializer to the initializer list. So this function is
> >       automatically called after dlopen().
> >     - make init_$(date +%s$$$RANDOM) a dummy symbol.
> >     - module_load first checks the presense of the symbol, if yes, call the
> >       functions in the initializer list. Else clean up and unload .so.
> > 
> > Does this enable multiple calls of module_init()?
> 
> Yes.  Basically you are delaying the constructors; that would work.
> 
> > OTOH. As for multiple spice modules, is it possible to solve it by having a
> > spice-common.o and link all spice modules to it, to share code?
> 
> Looks like there is global state in ui/spice-core.c, so likely no.
> 

What if the modules can be loaded by name? Then in spice-qemu-char.so, it can
call require_module("spice-core") before initializing itself, which will load
this dependency if not yet.  This may be the simplest implementation of
dependency resolving.

Fam