Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

Fix acl_from_text(3) - and, therefore, setfacl(1) - for user and group
names names starting with a digit.

MFC after: 1 month

_posix1e_acl_sort() never returns anything other than 0; change its
return type to void and update callers. This simplifies code and
fixes one place where the returned value was not actually checked.

Found with: Coverity Prevent
CID: 4791

Add NFSv4 ACL support to libc.

This adds the following functions to the acl(3) API: acl_add_flag_np,
acl_clear_flags_np, acl_create_entry_np, acl_delete_entry_np,
acl_delete_flag_np, acl_get_extended_np, acl_get_flag_np, acl_get_flagset_np,
acl_set_extended_np, acl_set_flagset_np, acl_to_text_np, acl_is_trivial_np,
acl_strip_np, acl_get_brand_np. Most of them are similar to what Darwin
does. There are no backward-incompatible changes.

Approved by: rwatson@

Make 'struct acl' larger, as required to support NFSv4 ACLs. Provide
compatibility interfaces in both kernel and libc.

Reviewed by: rwatson

Move _posix1e_acl_name_to_id out of acl_support.c and into
acl_from_text.c. Since acl_from_text.c is the only place it
is used, we can now make this internal utility function "static."

As a bonus, acl_set_fd() no longer pulls in getpwuid() for no reason.

MFC after: 7 days

o Separate acl_t into internal and external representations as
required by POSIX.1e. This maintains the current 'struct acl'
in the kernel while providing the generic external acl_t
interface required to complete the ACL editing library.
o Add the acl_get_entry() function.
o Convert the existing ACL utilities, getfacl and setfacl, to
fully make use of the ACL editing library.

Obtained from: TrustedBSD Project

o Update copyright dates.
o Rename internal library functions so that they are prefixed with
_posix1e or _POSIX1E, removing them from the application namespace (and
potential conflict with other ACL functions elsewhere in the system).

Obtained from: TrustedBSD Project

Minor fixes to library interface to improve POSIX.1e compliance. This
adds _np to a couple of function prototypes that provided more broad/useful
interfaces than POSIX.1e interfaces included.

Also, move from using a heuristic to identify POSIX.1e-semantic ACLs to
using different ACL types for non-POSIX.1e ACLs. This should clean up the
existing fuzzy logic that determined when acl_sort() should be applied
before kernel submission.

libposix1e provides userland library calls for the POSIX.1e security
interface. This commit introduces the library, as well as a modest
subset of the ACL calls, with some modifications to support multiple
ACL semantics.

Reviewed by: eivind