acl_valid man page

acl_valid — validate an ACL


Linux Access Control Lists library (libacl, -lacl).


#include <sys/types.h>
#include <sys/acl.h>

acl_valid(acl_t acl);


The acl_valid() function checks the ACL referred to by the argument acl for validity.

The three required entries ACL_USER_OBJ, ACL_GROUP_OBJ, and ACL_OTHER must exist exactly once in the ACL. If the ACL contains any ACL_USER or ACL_GROUP entries, then an ACL_MASK entry is also required. The ACL may contain at most one ACL_MASK entry.

The user identifiers must be unique among all entries of type ACL_USER. The group identifiers must be unique among all entries of type ACL_GROUP.

Return Value

The acl_valid() function returns the value 0 if successful; otherwise the value -1 is returned and the global variable errno is set to indicate the error.


If any of the following conditions occur, the acl_valid() function returns -1 and sets errno to the corresponding value:

The argument acl is not a valid pointer to an ACL.

The argument acl does not point to a valid ACL.

One or more of the required ACL entries is not present in acl.

The ACL contains entries that are not unique.


IEEE Std 1003.1e draft 17 (“POSIX.1e”, abandoned)

See Also

acl_check(3), acl_set_file(3), acl(5)


Derived from the FreeBSD manual pages written by Robert N M Watson ⟨⟩, and adapted for Linux by Andreas Gruenbacher ⟨⟩.

Referenced By

acl(5), acl_calc_mask(3), acl_check(3), acl_error(3), acl_set_fd(3), acl_set_file(3).

March 23, 2002