Merge pull request xapi-project#9 from koushikcgit/CA-191570

CA-191570: Make use of meaningful token while adding xenstore watch

src/xenstore_watch.ml

@@ -26,6 +26,7 @@ module IntMap = Map.Make(struct type t = int let compare = compare end)
 module IntSet = Set.Make(struct type t = int let compare = compare end)
 
 module type WATCH_ACTIONS = sig
+	val watch_token : int -> string
 	val interesting_paths_for_domain : int -> string -> string list
 	val watch_fired : Xenctrl.handle -> string -> Xenctrl.domaininfo IntMap.t -> IntSet.t -> unit
 	val unmanaged_domain : int -> string -> bool
@@ -34,14 +35,14 @@ module type WATCH_ACTIONS = sig
 	val domain_disappeared : Xenctrl.handle -> int -> unit
 end
 
-let watch xs path =
-	debug "xenstore watch %s" path;
-	Xs.watch xs path path
+let watch xs token path =
+	debug "xenstore watch path=%s token=%s" path token;
+	Xs.watch xs path token
 
-let unwatch xs path =
+let unwatch xs token path =
 	try
-		debug "xenstore unwatch %s" path;
-		Xs.unwatch xs path path
+		debug "xenstore unwatch path=%s token=%s" path token;
+		Xs.unwatch xs path token
 	with Xs_protocol.Enoent _ ->
 		debug "xenstore unwatch %s threw Xs_protocol.Enoent" path
 
@@ -75,16 +76,18 @@ module WatchXenstore = functor(Actions: WATCH_ACTIONS) -> struct
 		  let add_watches_for_domain xs domid uuid =
 		    debug "Adding watches for: domid %d" domid;
                     Actions.domain_appeared xc domid;
-		    List.iter (watch xs) (Actions.interesting_paths_for_domain domid uuid);
+		    let token = Actions.watch_token domid in
+		    List.iter (watch xs token) (Actions.interesting_paths_for_domain domid uuid);
 		    uuids := IntMap.add domid uuid !uuids;
 		    watches := IntSet.add domid !watches in
 
 		  let remove_watches_for_domain xs domid =
 		    debug "Removing watches for: domid %d" domid;
                     Actions.domain_disappeared xc domid;
+		    let token = Actions.watch_token domid in
 		    if IntMap.mem domid !uuids then begin
 		      let uuid = IntMap.find domid !uuids in
-		      List.iter (unwatch xs) (Actions.interesting_paths_for_domain domid uuid);
+		      List.iter (unwatch xs token) (Actions.interesting_paths_for_domain domid uuid);
 		      watches := IntSet.remove domid !watches;
 		      uuids := IntMap.remove domid !uuids;
 		    end in