Merge branch 'hans/ssh/port_leak/OTP-15397' into maint-21

* hans/ssh/port_leak/OTP-15397:
  ssh: Fix port leakage for daemons failing at start
  ssh: Add port close test

# Conflicts:
#	lib/ssh/test/ssh_basic_SUITE.erl

2 files changed, 62 insertions, 20 deletions

diff --git a/lib/ssh/src/ssh.erl b/lib/ssh/src/ssh.erl
index 086fa6e5f8..9281bf84a7 100644
--- a/lib/ssh/src/ssh.erl
+++ b/lib/ssh/src/ssh.erl
@@ -270,25 +270,38 @@ daemon(Host0, Port0, UserOptions0) when 0 =< Port0, Port0 =< 65535,
     try
         {Host1, UserOptions} = handle_daemon_args(Host0, UserOptions0),
         #{} = Options0 = ssh_options:handle_options(server, UserOptions),
-
-        {{Host,Port}, ListenSocket} =
-            open_listen_socket(Host1, Port0, Options0),
-
-        %% Now Host,Port is what to use for the supervisor to register its name,
-        %% and ListenSocket is for listening on connections. But it is still owned
-        %% by self()...
-
-        finalize_start(Host, Port, ?GET_OPT(profile, Options0),
-                       ?PUT_INTERNAL_OPT({lsocket,{ListenSocket,self()}}, Options0),
-                       fun(Opts, Result) ->
-                               {_, Callback, _} = ?GET_OPT(transport, Opts),
-                               receive
-                                   {request_control, ListenSocket, ReqPid} ->
-                                       ok = Callback:controlling_process(ListenSocket, ReqPid),
-                                       ReqPid ! {its_yours,ListenSocket},
-                                       Result
-                               end
-                       end)
+        {open_listen_socket(Host1, Port0, Options0), Options0}
+    of
+        {{{Host,Port}, ListenSocket}, Options1} ->
+            try
+                %% Now Host,Port is what to use for the supervisor to register its name,
+                %% and ListenSocket is for listening on connections. But it is still owned
+                %% by self()...
+                finalize_start(Host, Port, ?GET_OPT(profile, Options1),
+                               ?PUT_INTERNAL_OPT({lsocket,{ListenSocket,self()}}, Options1),
+                               fun(Opts, Result) ->
+                                       {_, Callback, _} = ?GET_OPT(transport, Opts),
+                                       receive
+                                           {request_control, ListenSocket, ReqPid} ->
+                                               ok = Callback:controlling_process(ListenSocket, ReqPid),
+                                               ReqPid ! {its_yours,ListenSocket},
+                                               Result
+                                       end
+                               end)
+            of
+                {error,Err} ->
+                    close_listen_socket(ListenSocket, Options1),
+                    {error,Err};
+                OK ->
+                    OK
+            catch
+                error:Error ->
+                    close_listen_socket(ListenSocket, Options1),
+                    error(Error);
+                exit:Exit ->
+                    close_listen_socket(ListenSocket, Options1),
+                    exit(Exit)
+            end
     catch
         throw:bad_fd ->
             {error,bad_fd};
@@ -524,6 +537,15 @@ open_listen_socket(_Host0, Port0, Options0) ->
     {{LHost,LPort}, LSock}.
 
 %%%----------------------------------------------------------------
+close_listen_socket(ListenSocket, Options) ->
+    try
+        {_, Callback, _} = ?GET_OPT(transport, Options),
+        Callback:close(ListenSocket)
+    catch
+        _C:_E -> ok
+    end.
+
+%%%----------------------------------------------------------------
 finalize_start(Host, Port, Profile, Options0, F) ->
     try
         %% throws error:Error if no usable hostkey is found
diff --git a/lib/ssh/test/ssh_basic_SUITE.erl b/lib/ssh/test/ssh_basic_SUITE.erl
index da94b5722f..5de6d52092 100644
--- a/lib/ssh/test/ssh_basic_SUITE.erl
+++ b/lib/ssh/test/ssh_basic_SUITE.erl
@@ -43,7 +43,9 @@ suite() ->
      {timetrap,{seconds,40}}].
 
 all() -> 
-    [{group, all_tests}].
+    [{group, all_tests},
+     daemon_already_started
+    ].
 
 groups() ->
     [{all_tests, [parallel], [{group, ssh_renegotiate_SUITE},
@@ -801,6 +803,24 @@ daemon_already_started(Config) when is_list(Config) ->
     ssh:stop_daemon(Pid).
 
 %%--------------------------------------------------------------------
+%%% Test that a failed daemon start does not leave the port open
+daemon_error_closes_port(Config) ->
+    GoodSystemDir = proplists:get_value(data_dir, Config),
+    Port = ssh_test_lib:inet_port(),
+    {error,_} = ssh_test_lib:daemon(Port, []), % No system dir
+    case ssh_test_lib:daemon(Port, [{system_dir, GoodSystemDir}]) of
+        {error,eaddrinuse} ->
+            {fail, "Port leakage"};
+        {error,Error} ->
+            ct:log("Strange error: ~p",[Error]),
+            {fail, "Strange error"};
+        {Pid, _Host, Port} ->
+            %% Ok
+            ssh:stop_daemon(Pid)
+    end.
+    
+
+%%--------------------------------------------------------------------
 %%% check that known_hosts is updated correctly
 known_hosts(Config) when is_list(Config) ->
     SystemDir = proplists:get_value(data_dir, Config),