acl_calc_mask(3) — Linux manual page


ACL_CALC_MASK(3)         Library Functions Manual       ACL_CALC_MASK(3)

NAME         top

       acl_calc_mask — calculate the file group class mask

LIBRARY         top

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

SYNOPSIS         top

       <sys/types.h> <sys/acl.h> int acl_calc_mask(acl_t *acl_p)

DESCRIPTION         top

       The acl_calc_mask() function calculates and sets the permissions
       associated with the ACL_MASK ACL entry of the ACL referred to by
       acl_p.  The value of the new permissions is the union of the
       permissions granted by all entries of tag type ACL_GROUP,
       ACL_GROUP_OBJ, or ACL_USER.  If the ACL referred to by acl_p
       already contains an ACL_MASK entry, its permissions are
       overwritten; if it does not contain an ACL_MASK entry, one is

       If the ACL referred to by acl_p does not contain enough space for
       the new ACL entry, then additional working storage may be
       allocated. If the working storage cannot be increased in the
       current location, then it may be relocated and the previous
       working storage is released and a pointer to the new working
       storage is returned via acl_p.

       The order of existing entries in the ACL is undefined after this

       Any existing ACL entry descriptors that refer to entries in the
       ACL continue to refer to those entries. Any existing ACL pointers
       that refer to the ACL referred to by acl_p continue to refer to
       the ACL.

RETURN VALUE         top

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

ERRORS         top

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

       [EINVAL]           The argument acl is not a valid pointer to an

       [ENOMEM]           The acl_calc_mask() function is unable to
                          allocate the memory required for an ACL_MASK
                          ACL entry.

STANDARDS         top

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

SEE ALSO         top

       acl_check(3), acl_get_entry(3), acl_valid(3), acl(5)

AUTHOR         top

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

COLOPHON         top

       This page is part of the acl (manipulating access control lists)
       project.  Information about the project can be found at  If you have a bug
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Linux ACL                    March 23, 2002             ACL_CALC_MASK(3)