• Contact: tech-userlevel
• Mentors: Antti Kantee
• Duration estimate: 3 months

IMPORTANT: This project was completed by Vyacheslav Matyushin. You may still contact the people above for details, but please do not submit an application for this project.

As is well-known, puffs(3) is the NetBSD userspace file system framework. It provides support for implementing file servers in userspace. A lesser known "cousin" of puffs is the Pass-to-Userspace Device, or pud(4) framework, which provides support for implementing character and block device servers in userspace. Both use putter(9) for transmitting requests to and from the kernel.

Currently, puffs includes a userspace support library: libpuffs. It provides two facets:

• file system routines and callback interface
• generic parts, including kernel request handling

On the other hand, pud is without a userspace support library and servers talk with kernel directly with read() and write().

The goal of the project is to modify libpuffs into a generic library which pud and puffs can share, and provide libpuffs and libpud built on this base. The submission should include a rough analysis of the source modules of libpuffs and what is going to happen to them during the project.

This project is fairly straightforward, but involves a reasonable amount of work. Plenty of documentation exists to make the learning curve manageable. This project is an excellent opportunity to practise getting your hands dirty with real world systems.