NAME

     acl_calc_mask — calculate the file group class mask

LIBRARY

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

SYNOPSIS

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

     int
     acl_calc_mask(acl_t *acl_p);

DESCRIPTION

     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 added.

     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 function.

     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

     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

     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 ACL.

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

STANDARDS

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

SEE ALSO

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

AUTHOR

     Derived from the FreeBSD manual pages written by Robert N M Watson <rwatson@FreeBSD.org>, and adapted for
     Linux by Andreas Gruenbacher <a.gruenbacher@bestbits.at>.