1 files changed, 7 insertions, 0 deletions
diff --git a/src/killswitch.vala b/src/killswitch.vala
index 08ee0cc..167d189 100644
--- a/src/killswitch.vala
+++ b/src/killswitch.vala
@@ -26,6 +26,8 @@
  */
 public interface KillSwitch: Object
 {
+  public abstract bool is_valid ();
+
   public abstract bool blocked { get; protected set; }
 
   /* Try to block/unblock bluetooth.
@@ -109,6 +111,11 @@ public class RfKillSwitch: KillSwitch, Object
       }
   }
 
+  public bool is_valid ()
+  {
+    return fd != -1;
+  }
+
   private bool on_channel_event (IOChannel source, IOCondition condition)
   {
     read_event ();