create an ACL from file permission bits
Linux Access Control Lists library (libacl, -lacl).
acl_from_mode() function creates a minimal ACL that
contains the three entries with tag types ACL_USER_OBJ, ACL_GROUP_OBJ, and
ACL_OTHER, with permissions corresponding to the owner, group, and other
permission bits of its argument mode.
On success, this function returns a pointer to the working storage. On error, a
(acl_t)NULL is returned, and
errno is set appropriately.
If any of the following conditions occur, the
acl_from_mode() function returns a value of
(acl_t)NULL and sets errno to
the corresponding value:
- The ACL working storage requires more memory than is allowed by the
hardware or system-imposed memory management constraints.
This is a non-portable, Linux specific extension to the ACL manipulation
functions defined in IEEE Std 1003.1e draft 17 (“POSIX.1e”,
Written by Andreas Gruenbacher