Post Syndicated from Lennart Poettering original https://0pointer.net/blog/projects/libabc.html

At the Kernel Summit in Prague last week Kay Sievers and I lead a session on
developing shared userspace libraries, for kernel hackers. More and more
userspace interfaces of the kernel (for example many which deal with storage,
audio, resource management, security, file systems or a number of other
subsystems) nowadays rely on a dedicated userspace component. As people who
work primarily in the plumbing layer of the Linux OS we noticed over and over
again that these libraries written by people who usually are at home on the
kernel side of things make the same mistakes repeatedly, thus making life for
the users of the libraries unnecessarily difficult. In our session we tried to
point out a number of these things, and in particular places where the usual
kernel hacking style translates badly into userspace shared library hacking.
Our hope is that maybe a few kernel developers have a look at our list of
recommendations and consider the points we are raising.

To make things easy we have put together an example skeleton library we
dubbed libabc, whose README
file includes all our points in terse form. It’s available on kernel.org:

The git repository and the README.

This list of recommendations draws inspiration from David Zeuthen’s and
Ulrich Drepper’s well known papers on the topic of writing shared libraries. In
the README linked above we try to distill this wealth of information into a
terse list of recommendations, with a couple of additions and with a strict
focus on a kernel hacker background.

Please have a look, and even if you are not a kernel hacker there might be
something useful to know in it, especially if you work on the lower layers of
our stack.

If you have any questions or additions, just ping us, or comment below!