read_from_dit
read_from_dit(PASSWD_MAPPING, domain, &key, &data);
read_from_dit(PASSWD_ADJUNCT_MAPPING, domain, &key, &data);
read_from_dit(AGEING_MAPPING, domain, &key, &data);
ret = read_from_dit(map->map_name, map->domain, key, &dat);
extern int read_from_dit(char *, char *, datum *, datum *);