[[!template id=project

title="Binary compatibility for puffs backend"

contact="""
[tech-kern](mailto:tech-kern@NetBSD.org), [tech-userlevel](mailto:tech-userlevel@NetBSD.org)
"""

category="kernel"
difficulty="medium"
duration="3 months"

description="""
Currently, the [[!template id=man name="puffs" section="3" collection="NetBSD-5.1"]] interface between the kernel and userspace uses various system structures for passing information. Examples are `struct stat` and `struct uucred`. If these change in layout (such as with the time_t size change in NetBSD 6.0), old puffs servers must be recompiled.

The project milestones are:

* *define* a binary-independent protocol
* *implement* support
* *measure* the performance difference with direct kernel struct passing
* if there is a huge difference, *investigate* the possibility for having both an internal and external protocol. The actual decision to include support will be made on the relative complexity of the code for dual support.

While this project will be partially implemented in the kernel, it is fairly well-contained and prior kernel experience is not necessary.

If there is time and interest, a suggested subproject is making sure that [[!template id=man name="p2k" section="3" collection="NetBSD-5.1"]] does not suffer from similar issues. This is a required subproject if dual support as mentioned above is not necessary.
"""
]]