mini-os: handle possibly overlong _nodename in init_consfront

The only current user that passes a non-NULL _nodename limits it to 64
bytes anyway.

Coverity-ID: 1054993
Signed-off-by: Matthew Daley <mattjd@gmail.com>
Acked-by: Samuel Thibault <samuel.thibault@ens-lyon.org>

extras/mini-os/console/xenbus.c

@@ -70,8 +70,10 @@ struct consfront_dev *init_consfront(char *_nodename)
 
     if (!_nodename)
         snprintf(nodename, sizeof(nodename), "device/console/%d", consfrontends);
-    else
-        strncpy(nodename, _nodename, sizeof(nodename));
+    else {
+        strncpy(nodename, _nodename, sizeof(nodename) - 1);
+        nodename[sizeof(nodename) - 1] = 0;
+    }
 
     printk("******************* CONSFRONT for %s **********\n\n\n", nodename);