static int etap_open(void *data)
{
	struct ethertap_data *pri = data;
	char *output;
	int data_fds[2], control_fds[2], err, output_len;

	err = tap_open_common(pri->dev, pri->gate_addr);
	if (err)
		return err;

	err = socketpair(AF_UNIX, SOCK_DGRAM, 0, data_fds);
	if (err) {
		err = -errno;
		printk(UM_KERN_ERR "etap_open - data socketpair failed - "
		       "err = %d\n", errno);
		return err;
	}

	err = socketpair(AF_UNIX, SOCK_STREAM, 0, control_fds);
	if (err) {
		err = -errno;
		printk(UM_KERN_ERR "etap_open - control socketpair failed - "
		       "err = %d\n", errno);
		goto out_close_data;
	}

	err = etap_tramp(pri->dev_name, pri->gate_addr, control_fds[0],
			 control_fds[1], data_fds[0], data_fds[1]);
	output_len = UM_KERN_PAGE_SIZE;
	output = uml_kmalloc(output_len, UM_GFP_KERNEL);
	read_output(control_fds[0], output, output_len);

	if (output == NULL)
		printk(UM_KERN_ERR "etap_open : failed to allocate output "
		       "buffer\n");
	else {
		printk("%s", output);
		kfree(output);
	}

	if (err < 0) {
		printk(UM_KERN_ERR "etap_tramp failed - err = %d\n", -err);
		goto out_close_control;
	}

	pri->data_fd = data_fds[0];
	pri->control_fd = control_fds[0];
	iter_addresses(pri->dev, etap_open_addr, &pri->control_fd);
	return data_fds[0];

out_close_control:
	close(control_fds[0]);
	close(control_fds[1]);
out_close_data:
	close(data_fds[0]);
	close(data_fds[1]);
	return err;
}
static int etap_open(void *data)
{
	struct ethertap_data *pri = data;
	char *output;
	int data_fds[2], control_fds[2], err, output_len;

	err = tap_open_common(pri->dev, pri->gate_addr);
	if(err) return(err);

	err = os_pipe(data_fds, 0, 0);
	if(err < 0){
		printk("data os_pipe failed - err = %d\n", -err);
		return(err);
	}

	err = os_pipe(control_fds, 1, 0);
	if(err < 0){
		printk("control os_pipe failed - err = %d\n", -err);
		return(err);
	}
	
	err = etap_tramp(pri->dev_name, pri->gate_addr, control_fds[0], 
			 control_fds[1], data_fds[0], data_fds[1]);
	output_len = page_size();
	output = um_kmalloc(output_len);
	read_output(control_fds[0], output, output_len);

	if(output == NULL)
		printk("etap_open : failed to allocate output buffer\n");
	else {
		printk("%s", output);
		kfree(output);
	}

	if(err < 0){
		printk("etap_tramp failed - err = %d\n", -err);
		return(err);
	}

	pri->data_fd = data_fds[0];
	pri->control_fd = control_fds[0];
	iter_addresses(pri->dev, etap_open_addr, &pri->control_fd);
	return(data_fds[0]);
}