Rudder

We want to provide generic methods for POSIX ACL.

The requirements are:

- we need to be able to manage N ACL on P files in a single Technique built with these generic methods,
- we need to be able to define at minimum a list of files, ideally some fileset

It seems necessary to propose several methods that would let the user choose the reporting level he wants (or need):

- one ACL on one File (very precise, but may become extremely verbose)
- one ACL on a file set
- N ACLs on a file
- N ACLs on a file set.

Even in the case where we have N ACLs on a fileset, we need to provide verbose error message tracing exactly what problem was encountered on what file.

We will need to propose at least 3 kinds of action (and so 3 kinds of methods):

- one that set ACL without touching other existing ones,
- one that set ACL exactly to what is provided as parameter (less prioritary),
- one that remove (one or all) ACLs.

These methods will need to check for libacl support (introduced in #12270) for agent capability support.