The richacl user-space utility and shared library.

Richacls are NFSv4 style ACLs, adapted to the use as a local Linux file
permission model, similar to POSIX ACLs. They are fully integrated with the
POSIX file permission model, and support the full NFSv4 ACL semantics. NFSv4
ACLs are largely based on Windows ACLs, which makes richacls largely compatible
with Windows ACLs as well.