...
if ((*type == IoTYPE_RDWR) && /* scary */
 (*(type+1) == IoTYPE_RDONLY || *(type+1) == IoTYPE_WRONLY) &&
 ((!num_svs || (tend > type+1 && tend[-1] != IoTYPE_PIPE)))) {
 TAINT_PROPER("open");
 mode[1] = *type++;
 writing = 1;
 }