int cg_get_attribute(const char *controller, const char *path, const char *attribute, char **ret);
int cg_set_group_access(const char *controller, const char *path, mode_t mode, uid_t uid, gid_t gid);
int cg_get_attribute(const char *controller, const char *path, const char *attribute, char **ret);
int cg_set_group_access(const char *controller, const char *path, mode_t mode, uid_t uid, gid_t gid);