TCAP: resolve DHA / CCO dependencies on TC-U initiated BEGIN

Prior to this patch, DHA needs to know the CCO pid, and CCO needed to
know the DHA pid at startup.  The idea was to start CCO from within the
init() callback in DHA.  However, this caused a deadlock in the
supervisor.

We now use the locally registred process names (tcap_cco_DLGID) to
resolve the process.  However, it might be cleaner to use an ets table
at some later point.  For now it is nice to see the name of each process
in pman for debugging...

TCAP/src/ITU/tcap_cco_server.erl

@@ -68,11 +68,16 @@
 %%----------------------------------------------------------------------
 
 %% initialize the server
-init([Supervisor, USAP, DialogueID, DHA]) ->
+init([Supervisor, USAP, DialogueID]) ->
 	process_flag(trap_exit, true),
+	DHA = list_to_atom("tcap_dha_" ++ integer_to_list(DialogueID)),
 	{ok, #state{supervisor = Supervisor, usap = USAP, dha = DHA,
 		    dialogueID = DialogueID, components = []}}.
 
+%% set the DHA pid
+handle_call(set_dha, From, State) ->
+	{noreply, State#state{dha = From}};
+
 %% shutdown the server
 handle_call(stop, _From, State) ->
 	{stop, shutdown, ok, State};

TCAP/src/ITU/tcap_dha_fsm.erl

@@ -84,14 +84,8 @@
 init({USAP, DialogueID, TCO, Supervisor}) ->
 	init({USAP, DialogueID, TCO, undefined, Supervisor});
 init({USAP, DialogueID, TCO, SupId, Supervisor}) ->
-	%% Start a Component Coordinator (CCO) process
-	ChildName = list_to_atom("cco_sup_" ++ integer_to_list(DialogueID)),
-	ChildArgs = [USAP, DialogueID, self()],
-	StartFunc = {supervisor, start_link, [tcap_components_sup, ChildArgs]},
-	ChildSpec = {ChildName, StartFunc, permanent, infinity,
-			supervisor, [tcap_components_sup]},
-	{ok, CCO} = supervisor:start_child(Supervisor, ChildSpec),
 	ets:insert(tcap_dha, {DialogueID, self()}),
+	CCO = list_to_atom("tcap_cco_" ++ integer_to_list(DialogueID)),
 	process_flag(trap_exit, true),
 	{ok, idle, #state{usap = USAP, did = DialogueID,
 			tco = TCO, supid = SupId, cco = CCO}}.
@@ -839,5 +833,5 @@ code_change(_OldVsn, StateName, State, _Extra) ->
 
 
 % front-end function called by tcap_user to get CCO for given DHA
-get_cco_pid(DHA) when is_pid(DHA) ->
+get_cco_pid(DHA) ->
 	gen_fsm:sync_send_all_state_event(DHA, get_cco_pid).

TCAP/src/tcap_components_sup.erl

@@ -46,11 +46,10 @@
 %% call backs needed for supervisor behaviour
 -export([init/1]).
 
-init([USAP, ID, DHA]) ->
+init([USAP, ID]) ->
 	Name = list_to_atom("tcap_cco_" ++ integer_to_list(ID)),
-	StartArgs = [tcap_cco_server, [self(), USAP, ID, DHA], [{debug, [trace]}]],
+	StartArgs = [{local, Name}, tcap_cco_server, [self(), USAP, ID], [{debug, [trace]}]],
 	StartFunc = {gen_server, start_link, StartArgs},
-	ChildSpec = {Name, StartFunc, temporary, 4000, worker,
-			[tcap_cco_server]},
+	ChildSpec = {cco, StartFunc, temporary, 4000, worker, [tcap_cco_server]},
 	{ok,{{one_for_all, 0, 1}, [ChildSpec]}}.
 

TCAP/src/tcap_dialogue_sup.erl

@@ -46,18 +46,33 @@
 %% call backs needed for supervisor behaviour
 -export([init/1]).
 
+
+%% Gen child specification for Component Coordinator (CCO) supervisor process
+gen_comp_sup_spec(USAP, DialogueID) ->
+	ChildName = list_to_atom("tcap_components_sup_" ++ integer_to_list(DialogueID)),
+	ChildArgs = [USAP, DialogueID],
+	StartArgs = [{local, ChildName}, tcap_components_sup, ChildArgs],
+	StartFunc = {supervisor, start_link, StartArgs},
+	ChildSpec = {cco_sup, StartFunc, permanent, infinity,
+			supervisor, [tcap_components_sup]},
+	ChildSpec.
+
 %% when started from TCO
 init({USAP, LocalTID, TCO, SupId}) ->
-	StartArgs = [tcap_dha_fsm, [{USAP, LocalTID, TCO, SupId, self()}], []],
+	StartName = list_to_atom("tcap_dha_" ++ integer_to_list(LocalTID)),
+	StartArgs = [{local, StartName}, tcap_dha_fsm, [{USAP, LocalTID, TCO, SupId, self()}], []],
 	StartFunc = {gen_fsm, start_link, StartArgs},
+	ChildSpecComp = gen_comp_sup_spec(USAP, LocalTID),
 	ChildSpec = {dha, StartFunc, permanent, 4000, worker,
 			[tcap_dha_fsm]},
-	{ok,{{one_for_all, 0, 1}, [ChildSpec]}};
+	{ok,{{one_for_all, 0, 1}, [ChildSpecComp, ChildSpec]}};
 
 %% when started from TSM
 init({USAP, LocalTID, TCO}) ->
-	StartArgs = [tcap_dha_fsm, {USAP, LocalTID, TCO, self()}, []],
+	StartName = list_to_atom("tcap_dha_" ++ integer_to_list(LocalTID)),
+	StartArgs = [{local, StartName}, tcap_dha_fsm, {USAP, LocalTID, TCO, self()}, []],
 	StartFunc = {gen_fsm, start_link, StartArgs},
+	ChildSpecComp = gen_comp_sup_spec(USAP, LocalTID),
 	ChildSpec = {dha, StartFunc, permanent, 4000, worker,
 			[tcap_dha_fsm]},
-	{ok,{{one_for_all, 0, 1}, [ChildSpec]}}.
+	{ok,{{one_for_all, 0, 1}, [ChildSpecComp, ChildSpec]}}.

TCAP/src/tcap_invocation_sup.erl

@@ -48,7 +48,7 @@
 
 init([USAP, InvokeID]) ->
 	Name = list_to_atom("tcap_ism_" ++ integer_to_list(InvokeID)),
-	StartArgs = [tcap_ism_fsm, [USAP, InvokeID], []],
+	StartArgs = [{local, Name}, tcap_ism_fsm, [USAP, InvokeID], []],
 	StartFunc = {gen_fsm, start_link, StartArgs},
 	ChildSpec = {Name, StartFunc, temporary, 4000, worker,
 			[tcap_ism_sup]},

TCAP/src/tcap_transaction_sup.erl

@@ -48,7 +48,7 @@
 
 init({NSAP, USAP, TID, SupRef}) ->
 	Name = list_to_atom("tcap_tsm_" ++ integer_to_list(TID)),
-	StartArgs = [tcap_tsm_fsm, [NSAP, USAP, TID, self(), SupRef], []],
+	StartArgs = [{local, Name}, tcap_tsm_fsm, [NSAP, USAP, TID, self(), SupRef], []],
 	StartFunc = {gen_fsm, start_link, StartArgs},
 	ChildSpec = {Name, StartFunc, permanent, 1000, worker, [tcap_tsm_fsm]},
 	{ok,{{one_for_all, 0, 1}, [ChildSpec]}}.

TCAP/src/tcap_user.erl

@@ -95,6 +95,7 @@ start_sap(SccpModule, Args, Opts) ->
 
 start_new_dha(TCO, LocalTID) ->
 	Args = {self(), LocalTID, TCO},
+	% this returns the _supervisor_ pid, not DHA
 	{ok, Pid} = supervisor:start_link(tcap_dialogue_sup, Args),
-	Pid.
+	list_to_atom("tcap_dha_" ++ integer_to_list(LocalTID)).