efidp_parse_device_path
len = efidp_parse_device_path(dptxt, out, 8192);
ssize_t efidp_parse_device_path(char *path, efidp out, size_t max);
efidp_parse_device_path(walker, dp, sizeof(dpbuf));
dplen = efidp_parse_device_path(walker, dp, dplen);