generate a POSIX.1e ACL access control decision using vnode
This call implements the logic for the UNIX
discretionary file security model with POSIX.1e ACL extensions. It accepts the
vnodes type type, owning UID
file_uid, owning GID file_gid,
access ACL for the file acl, desired access mode
accmode, requesting credential
cred, and an optional call-by-reference
int pointer returning whether or not privilege was
required for successful evaluation of the call; the
privused pointer may be set to
type, uid_t file_uid, gid_t
file_gid, struct acl *acl,
accmode_t accmode, struct ucred
*cred, int *privused);
NULL by the caller in order not to be informed of
privilege information, or it may point to an integer that will be set to 1 if
privilege is used, and 0 otherwise.
This call is intended to support implementations of
which will use their own access methods to retrieve the vnode properties,
and then invoke
vaccess_acl_posix1e() in order to
perform the actual check. Implementations of
may choose to implement additional security mechanisms whose results will be
composed with the return value.
The algorithm used by
vaccess_acl_posix1e() is based on the POSIX.1e ACL
evaluation algorithm. The algorithm selects a matching
entry from the access ACL, which may then be composed with an available ACL
mask entry, providing UNIX security
Once appropriate protections are selected for the current
credential, the requested access mode, in combination with the vnode type,
will be compared with the discretionary rights available for the credential.
If the rights granted by discretionary protections are insufficient, then
super-user privilege, if available for the credential, will also be
vaccess_acl_posix1e() will return 0 on success, or a
non-zero error value on failure.
This manual page and the current implementation of
- Permission denied. An attempt was made to access a file in a way forbidden
by its file access permissions.
- Operation not permitted. An attempt was made to perform an operation
limited to processes with appropriate privileges or to the owner of a file
or other resource.
vaccess_acl_posix1e() were written by
This manual page should include a full description of the POSIX.1e ACL
evaluation algorithm, or cross reference another page that does.