Ignore tcp errors during close request to eldap

If underlying tcp connection is closed and LDAP operation returned tcp error,
then client applications tend to close ldap handle with eldap:close.
This will cause do_unbind to throw gen_tcp_error, which is unhandled
and will be sent to linked process as {nocatch, {gen_tcp_error, ...}}.
eldap should ignore gen_tcp_error during close, because it will be closing anyway.

2 files changed, 32 insertions, 2 deletions

diff --git a/lib/eldap/src/eldap.erl b/lib/eldap/src/eldap.erl
index dc236f8a44..8994df10eb 100644
--- a/lib/eldap/src/eldap.erl
+++ b/lib/eldap/src/eldap.erl
@@ -564,7 +564,12 @@ loop(Cpid, Data) ->
             ?MODULE:loop(Cpid, NewData);
 
 	{_From, close} ->
-	    {no_reply,_NewData} = do_unbind(Data),
+        % Ignore tcp error if connection is already closed.
+        try do_unbind(Data) of
+            {no_reply,_NewData} -> ok
+        catch
+            throw:{gen_tcp_error, _TcpErr} -> ok
+        end,
 	    unlink(Cpid),
 	    exit(closed);
 
diff --git a/lib/eldap/test/eldap_basic_SUITE.erl b/lib/eldap/test/eldap_basic_SUITE.erl
index 9a23f74e22..536e891a1e 100644
--- a/lib/eldap/test/eldap_basic_SUITE.erl
+++ b/lib/eldap/test/eldap_basic_SUITE.erl
@@ -94,7 +94,8 @@ connection_tests() ->
      client_side_start_tls_timeout,
      client_side_bind_timeout,
      client_side_add_timeout,
-     client_side_search_timeout
+     client_side_search_timeout,
+     close_after_tcp_error
     ].
 
 
@@ -312,6 +313,30 @@ tcp_connection(Config) ->
     end.
 
 %%%----------------------------------------------------------------
+
+close_after_tcp_error(Config) ->
+    Host = proplists:get_value(listen_host, Config),
+    Port = proplists:get_value(listen_port, Config),
+    Opts = proplists:get_value(tcp_connect_opts, Config),
+    T = 1000,
+    case eldap:open([Host], [{timeout,T},{port,Port}|Opts]) of
+    {ok,H} ->
+        Sl = proplists:get_value(listen_socket, Config),
+        gen_tcp:close(Sl),
+        {error,{gen_tcp_error,closed}} = eldap:simple_bind(H, anon, anon),
+        ok = eldap:close(H),
+        wait_for_close(H);
+    Other -> ct:fail("eldap:open failed: ~p",[Other])
+    end.
+
+wait_for_close(H) ->
+    case erlang:is_process_alive(H) of
+        true  -> timer:sleep(100),
+                 wait_for_close(H);
+        false -> ok
+    end.
+
+%%%----------------------------------------------------------------
 ssl_connection(Config) ->
     Host = proplists:get_value(listen_host, Config),
     Port = proplists:get_value(ssl_listen_port, Config),