XEP-0198: Don't drop session on failed resume

The 'previd' value provided by the client during a session resume
request includes the client's JID and ejabberd's session ID.  If there
is a session for the requested JID but with a different session ID,
resumption should fail, but that session shouldn't be closed.  This
commit makes sure the latter won't happen.

In practice, this will only make a difference in odd corner cases.

diff --git a/src/ejabberd_c2s.erl b/src/ejabberd_c2s.erl
index 5d0cc9c08825e571915b0f388de8f45af17b6a3d..996a3c81d13dc11e914a536e16a86de363cc7222 100644 (file)
--- a/src/ejabberd_c2s.erl
+++ b/src/ejabberd_c2s.erl
@@ -1312,8 +1312,8 @@ handle_sync_event(get_subscribed, _From, StateName,
                  StateData) ->
     Subscribed = (?SETS):to_list(StateData#state.pres_f),
     {reply, Subscribed, StateName, StateData};
-handle_sync_event(resume_session, _From, _StateName,
-                 StateData) ->
+handle_sync_event({resume_session, Time}, _From, _StateName,
+                 StateData) when element(1, StateData#state.sid) == Time ->
     %% The old session should be closed before the new one is opened, so we do
     %% this here instead of leaving it to the terminate callback
     ejabberd_sm:close_session(StateData#state.sid,
@@ -1321,6 +1321,9 @@ handle_sync_event(resume_session, _From, _StateName,
                              StateData#state.server,
                              StateData#state.resource),
     {stop, normal, {ok, StateData}, StateData#state{mgmt_state = resumed}};
+handle_sync_event({resume_session, _Time}, _From, StateName,
+                 StateData) ->
+    {reply, {error, <<"Previous session not found">>}, StateName, StateData};
 handle_sync_event(_Event, _From, StateName,
                  StateData) ->
     Reply = ok, fsm_reply(Reply, StateName, StateData).
@@ -2894,8 +2897,8 @@ inherit_session_state(#state{user = U, server = S} = StateData, ResumeID) ->
                {error, <<"Previous session PID not found">>};
            OldPID ->
                OldSID = {Time, OldPID},
-               case catch resume_session(OldPID) of
-                 {ok, #state{sid = OldSID} = OldStateData} ->
+               case catch resume_session(OldSID) of
+                 {ok, OldStateData} ->
                      NewSID = {Time, self()}, % Old time, new PID
                      Priority = case OldStateData#state.pres_last of
                                   undefined ->
@@ -2927,6 +2930,8 @@ inherit_session_state(#state{user = U, server = S} = StateData, ResumeID) ->
                                           mgmt_stanzas_in = OldStateData#state.mgmt_stanzas_in,
                                           mgmt_stanzas_out = OldStateData#state.mgmt_stanzas_out,
                                           mgmt_state = active}};
+                 {error, Msg} ->
+                     {error, Msg};
                  _ ->
                      {error, <<"Cannot grab session state">>}
                end
@@ -2935,8 +2940,8 @@ inherit_session_state(#state{user = U, server = S} = StateData, ResumeID) ->
          {error, <<"Invalid 'previd' value">>}
     end.
 
-resume_session(FsmRef) ->
-    (?GEN_FSM):sync_send_all_state_event(FsmRef, resume_session, 3000).
+resume_session({Time, PID}) ->
+    (?GEN_FSM):sync_send_all_state_event(PID, {resume_session, Time}, 3000).
 
 make_resume_id(StateData) ->
     {Time, _} = StateData#state.sid,