From 5039b751f4c4c42c27aa184c16ec09715286192b Mon Sep 17 00:00:00 2001
From: terry-xiaoyu <506895667@qq.com>
Date: Tue, 17 Apr 2018 16:52:05 +0800
Subject: [PATCH] clean dead persistent session on connect

---
 src/emqttd_packet.erl   | 12 ++++++------
 src/emqttd_protocol.erl | 16 ++++++++--------
 src/emqttd_sm.erl       | 21 +++++++++++----------
 3 files changed, 25 insertions(+), 24 deletions(-)

diff --git a/src/emqttd_packet.erl b/src/emqttd_packet.erl
index f269f3dbe..d909089d1 100644
--- a/src/emqttd_packet.erl
+++ b/src/emqttd_packet.erl
@@ -56,7 +56,7 @@ format_header(#mqtt_packet_header{type = Type,
                                   dup = Dup,
                                   qos = QoS,
                                   retain = Retain}, S) ->
-    S1 = if 
+    S1 = if
              S == undefined -> <<>>;
              true           -> [", ", S]
          end,
@@ -78,13 +78,13 @@ format_variable(#mqtt_packet_connect{
                  clean_sess    = CleanSess,
                  keep_alive    = KeepAlive,
                  client_id     = ClientId,
-                 will_topic    = WillTopic, 
-                 will_msg      = WillMsg, 
-                 username      = Username, 
+                 will_topic    = WillTopic,
+                 will_msg      = WillMsg,
+                 username      = Username,
                  password      = Password}) ->
     Format = "ClientId=~s, ProtoName=~s, ProtoVsn=~p, CleanSess=~s, KeepAlive=~p, Username=~s, Password=~s",
     Args = [ClientId, ProtoName, ProtoVer, CleanSess, KeepAlive, Username, format_password(Password)],
-    {Format1, Args1} = if 
+    {Format1, Args1} = if
                         WillFlag -> { Format ++ ", Will(Q~p, R~p, Topic=~s, Msg=~s)",
                                       Args ++ [WillQoS, i(WillRetain), WillTopic, WillMsg] };
                         true -> {Format, Args}
@@ -93,7 +93,7 @@ format_variable(#mqtt_packet_connect{
 
 format_variable(#mqtt_packet_connack{ack_flags   = AckFlags,
                                      return_code = ReturnCode}) ->
-    io_lib:format("AckFlags=~p, RetainCode=~p", [AckFlags, ReturnCode]);
+    io_lib:format("AckFlags=~p, ReturnCode=~p", [AckFlags, ReturnCode]);
 
 format_variable(#mqtt_packet_publish{topic_name = TopicName,
                                      packet_id  = PacketId}) ->
diff --git a/src/emqttd_protocol.erl b/src/emqttd_protocol.erl
index 3531b165f..ea6a11ebf 100644
--- a/src/emqttd_protocol.erl
+++ b/src/emqttd_protocol.erl
@@ -137,7 +137,7 @@ session(#proto_state{session = Session}) ->
 
 %% CONNECT – Client requests a connection to a Server
 
-%% A Client can only send the CONNECT Packet once over a Network Connection. 
+%% A Client can only send the CONNECT Packet once over a Network Connection.
 -spec(received(mqtt_packet(), proto_state()) -> {ok, proto_state()} | {error, term()}).
 received(Packet = ?PACKET(?CONNECT),
          State = #proto_state{connected = false, stats_data = Stats}) ->
@@ -228,7 +228,8 @@ process(?CONNECT_PACKET(Var), State0) ->
                             %% ACCEPT
                             {?CONNACK_ACCEPT, SP, State2#proto_state{session = Session, is_superuser = IsSuperuser}};
                         {error, Error} ->
-                            {stop, {shutdown, Error}, State2}
+                            ?LOG(error, "Username '~s' login failed for ~p", [Username, Error], State2),
+                            {?CONNACK_SERVER, false, State2}
                     end;
                 {error, Reason}->
                     ?LOG(error, "Username '~s' login failed for ~p", [Username, Reason], State1),
@@ -449,14 +450,14 @@ start_keepalive(Sec, #proto_state{keepalive_backoff = Backoff}) when Sec > 0 ->
 
 validate_connect(Connect = #mqtt_packet_connect{}, ProtoState) ->
     case validate_protocol(Connect) of
-        true -> 
+        true ->
             case validate_clientid(Connect, ProtoState) of
-                true -> 
+                true ->
                     ?CONNACK_ACCEPT;
-                false -> 
+                false ->
                     ?CONNACK_INVALID_ID
             end;
-        false -> 
+        false ->
             ?CONNACK_PROTO_VER
     end.
 
@@ -498,7 +499,7 @@ validate_packet(?SUBSCRIBE_PACKET(_PacketId, TopicTable)) ->
 validate_packet(?UNSUBSCRIBE_PACKET(_PacketId, Topics)) ->
     validate_topics(filter, Topics);
 
-validate_packet(_Packet) -> 
+validate_packet(_Packet) ->
     ok.
 
 validate_topics(_Type, []) ->
@@ -593,4 +594,3 @@ unmount(MountPoint, Msg = #mqtt_message{topic = Topic}) ->
         {MountPoint, Topic0} -> Msg#mqtt_message{topic = Topic0};
         _ -> Msg
     end.
-
diff --git a/src/emqttd_sm.erl b/src/emqttd_sm.erl
index e2e332041..5d9b900c3 100644
--- a/src/emqttd_sm.erl
+++ b/src/emqttd_sm.erl
@@ -183,15 +183,16 @@ handle_cast(Msg, State) ->
 handle_info({'DOWN', MRef, process, DownPid, _Reason}, State) ->
     case dict:find(MRef, State#state.monitors) of
         {ok, ClientId} ->
-            case mnesia:dirty_read({mqtt_session, ClientId}) of
-                [] ->
-                    ok;
-                [Sess = #mqtt_session{sess_pid = DownPid}] ->
-                    mnesia:dirty_delete_object(Sess);
-                [_Sess] ->
-                    ok
-            end,
-            {noreply, erase_monitor(MRef, State), hibernate};
+            NewState =
+              case mnesia:dirty_read({mqtt_session, ClientId}) of
+                  [] -> State;
+                  [Sess = #mqtt_session{sess_pid = DownPid}] ->
+                      mnesia:dirty_delete_object(Sess),
+                      erase_monitor(MRef, State);
+                  [_Sess] ->
+                      State
+              end,
+            {noreply, NewState, hibernate};
         error ->
             lager:error("MRef of session ~p not found", [DownPid]),
             {noreply, State}
@@ -256,6 +257,7 @@ resume_session(Session = #mqtt_session{client_id = ClientId, sess_pid = SessPid}
             {ok, SessPid};
         false ->
             ?LOG(error, "Cannot resume ~p which seems already dead!", [SessPid], Session),
+            remove_session(Session),
             {error, session_died}
     end;
 
@@ -305,4 +307,3 @@ monitor_session(ClientId, SessPid, State = #state{monitors = Monitors}) ->
 erase_monitor(MRef, State = #state{monitors = Monitors}) ->
     erlang:demonitor(MRef, [flush]),
     State#state{monitors = dict:erase(MRef, Monitors)}.
-