1.1 --- a/tools/console/daemon/io.c	Thu Mar 30 11:54:07 2006 +0100
     1.2 +++ b/tools/console/daemon/io.c	Thu Mar 30 11:55:07 2006 +0100
     1.3 @@ -434,26 +434,37 @@ void enum_domains(void)
     1.4  	}
     1.5  }
     1.6  
     1.7 +static int ring_free_bytes(struct domain *dom)
     1.8 +{
     1.9 +	struct xencons_interface *intf = dom->interface;
    1.10 +	XENCONS_RING_IDX cons, prod, space;
    1.11 +
    1.12 +	cons = intf->in_cons;
    1.13 +	prod = intf->in_prod;
    1.14 +	mb();
    1.15 +
    1.16 +	space = prod - cons;
    1.17 +	if (space > sizeof(intf->in))
    1.18 +		return 0; /* ring is screwed: ignore it */
    1.19 +
    1.20 +	return (sizeof(intf->in) - space);
    1.21 +}
    1.22 +
    1.23  static void handle_tty_read(struct domain *dom)
    1.24  {
    1.25  	ssize_t len = 0;
    1.26  	char msg[80];
    1.27  	int i;
    1.28  	struct xencons_interface *intf = dom->interface;
    1.29 -	XENCONS_RING_IDX cons, prod;
    1.30 +	XENCONS_RING_IDX prod;
    1.31  
    1.32 -	cons = intf->in_cons;
    1.33 -	prod = intf->in_prod;
    1.34 -	mb();
    1.35 +	len = ring_free_bytes(dom);
    1.36 +	if (len == 0)
    1.37 +		return;
    1.38  
    1.39 -	if (sizeof(intf->in) > (prod - cons))
    1.40 -		len = sizeof(intf->in) - (prod - cons);
    1.41  	if (len > sizeof(msg))
    1.42  		len = sizeof(msg);
    1.43  
    1.44 -	if (len == 0)
    1.45 -		return;
    1.46 -
    1.47  	len = read(dom->tty_fd, msg, len);
    1.48  	if (len < 1) {
    1.49  		close(dom->tty_fd);
    1.50 @@ -465,6 +476,7 @@ static void handle_tty_read(struct domai
    1.51  			shutdown_domain(dom);
    1.52  		}
    1.53  	} else if (domain_is_valid(dom->domid)) {
    1.54 +		prod = intf->in_prod;
    1.55  		for (i = 0; i < len; i++) {
    1.56  			intf->in[MASK_XENCONS_IDX(prod++, intf->in)] =
    1.57  				msg[i];
    1.58 @@ -514,7 +526,7 @@ static void handle_ring_read(struct doma
    1.59  	(void)write_sync(dom->evtchn_fd, &v, sizeof(v));
    1.60  }
    1.61  
    1.62 -static void handle_xs(int fd)
    1.63 +static void handle_xs(void)
    1.64  {
    1.65  	char **vec;
    1.66  	int domid;
    1.67 @@ -560,7 +572,7 @@ void handle_io(void)
    1.68  			}
    1.69  
    1.70  			if (d->tty_fd != -1) {
    1.71 -				if (!d->is_dead)
    1.72 +				if (!d->is_dead && ring_free_bytes(d))
    1.73  					FD_SET(d->tty_fd, &readfds);
    1.74  
    1.75  				if (!buffer_empty(&d->buffer))
    1.76 @@ -572,7 +584,7 @@ void handle_io(void)
    1.77  		ret = select(max_fd + 1, &readfds, &writefds, 0, NULL);
    1.78  
    1.79  		if (FD_ISSET(xs_fileno(xs), &readfds))
    1.80 -			handle_xs(xs_fileno(xs));
    1.81 +			handle_xs();
    1.82  
    1.83  		for (d = dom_head; d; d = n) {
    1.84  			n = d->next;