[yocto] bbclass and recipe environnement

[Paul Goulpié]

Hello,
I am creating a bbclass of type image_types. The purpose of this class 
is to generate an archive that contains among others ipk packages that 
are created by the recipes that compose my rootfs.
My question is: how can I get the path of the IPK file for a given 
recipe from the bbclass that is being created.
More generally: how to access the environment of an application recipe 
from a bbclass.

Thanking you.