From 5e7f234ac8b7becf77e0090a4424885766590377 Mon Sep 17 00:00:00 2001
From: Christoph Scholz <christoph.scholz@gmail.com>
Date: Sun, 27 Jan 2019 17:40:43 +0100
Subject: [PATCH] disallow room creation if archive not empty and
 clear_archive_on_room_destroy is false

---
 src/mod_mam.erl | 12 +++++++++---
 src/mod_muc.erl | 14 +++++++++++---
 2 files changed, 20 insertions(+), 6 deletions(-)

diff --git a/src/mod_mam.erl b/src/mod_mam.erl
index 5f6bfa089..7dc80e462 100644
--- a/src/mod_mam.erl
+++ b/src/mod_mam.erl
@@ -41,7 +41,7 @@
 	 delete_old_messages/2, get_commands_spec/0, msg_to_el/4,
 	 get_room_config/4, set_room_option/3, offline_message/1, export/1,
 	 mod_options/1, remove_mam_for_user_with_peer/3, remove_mam_for_user/2,
-	 is_empty_for_user/2, is_empty_for_room/3]).
+	 is_empty_for_user/2, is_empty_for_room/3, check_create_room/4]).
 
 -include("xmpp.hrl").
 -include("logger.hrl").
@@ -132,7 +132,8 @@ start(Host, Opts) ->
 		    ejabberd_hooks:add(remove_room, Host, ?MODULE,
 				       remove_room, 50);
 		false ->
-		    ok
+		    ejabberd_hooks:add(check_create_room, Host, ?MODULE,
+				       check_create_room, 50)
 	    end,
 	    ejabberd_commands:register_commands(get_commands_spec());
 	Err ->
@@ -207,7 +208,8 @@ stop(Host) ->
 	    ejabberd_hooks:delete(remove_room, Host, ?MODULE,
 				  remove_room, 50);
 	false ->
-	    ok
+	    ejabberd_hooks:delete(check_create_room, Host, ?MODULE,
+				  check_create_room, 50)
     end,
     case gen_mod:is_loaded_elsewhere(Host, ?MODULE) of
         false ->
@@ -589,6 +591,10 @@ is_empty_for_room(LServer, Name, Host) ->
     Mod = gen_mod:db_mod(LServer, ?MODULE),
     Mod:is_empty_for_room(LServer, LName, LHost).
 
+-spec check_create_room(boolean(), binary(), binary(), binary()) -> boolean().
+check_create_room(Acc, ServerHost, RoomID, Host) ->
+    Acc and is_empty_for_room(ServerHost, RoomID, Host).
+
 %%%===================================================================
 %%% Internal functions
 %%%===================================================================
diff --git a/src/mod_muc.erl b/src/mod_muc.erl
index 29474e511..ae3c6f9f7 100644
--- a/src/mod_muc.erl
+++ b/src/mod_muc.erl
@@ -65,7 +65,8 @@
 	 iq_set_register_info/5,
 	 count_online_rooms_by_user/3,
 	 get_online_rooms_by_user/3,
-	 can_use_nick/4]).
+	 can_use_nick/4,
+	 check_create_room/4]).
 
 -export([init/1, handle_call/3, handle_cast/2,
 	 handle_info/2, terminate/2, code_change/3,
@@ -112,10 +113,14 @@
 %% API
 %%====================================================================
 start(Host, Opts) ->
+    ejabberd_hooks:add(check_create_room, Host, ?MODULE,
+               check_create_room, 50),
     gen_mod:start_child(?MODULE, Host, Opts).
 
 stop(Host) ->
     Rooms = shutdown_rooms(Host),
+    ejabberd_hooks:delete(check_create_room, Host, ?MODULE,
+               check_create_room, 50),
     gen_mod:stop_child(?MODULE, Host),
     {wait, Rooms}.
 
@@ -442,7 +447,9 @@ do_route1(Host, ServerHost, Access, HistorySize, RoomShaper,
 		true ->
 		    case check_user_can_create_room(
 			   ServerHost, AccessCreate, From, Room) and
-			check_create_roomid(ServerHost, Room) of
+			ejabberd_hooks:run_fold(check_create_room,
+					ServerHost, true,
+					[ServerHost, Room, Host]) of
 			true ->
 			    {ok, Pid} = start_new_room(
 					  Host, ServerHost, Access,
@@ -611,9 +618,10 @@ check_user_can_create_room(ServerHost, AccessCreate,
       _ -> false
     end.
 
-check_create_roomid(ServerHost, RoomID) ->
+check_create_room(Acc, ServerHost, RoomID, _Host) ->
     Max = gen_mod:get_module_opt(ServerHost, ?MODULE, max_room_id),
     Regexp = gen_mod:get_module_opt(ServerHost, ?MODULE, regexp_room_id),
+    Acc and
     (byte_size(RoomID) =< Max) and
     (re:run(RoomID, Regexp, [unicode, {capture, none}]) == match).