Merge branch 'hans/ssh/closed_chan_block/OTP-14939' into maint

* hans/ssh/closed_chan_block/OTP-14939:
  ssh: Fix the bug
  ssh: Extend testcase to check the bug

2 files changed, 46 insertions, 17 deletions

diff --git a/lib/ssh/src/ssh_connection_handler.erl b/lib/ssh/src/ssh_connection_handler.erl
index c8ac3a9c04..e11d3adee4 100644
--- a/lib/ssh/src/ssh_connection_handler.erl
+++ b/lib/ssh/src/ssh_connection_handler.erl
@@ -1174,17 +1174,25 @@ handle_event({call,_}, _, StateName, _) when not ?CONNECTED(StateName) ->
 
 handle_event({call,From}, {request, ChannelPid, ChannelId, Type, Data, Timeout}, StateName, D0) 
   when ?CONNECTED(StateName) ->
-    D = handle_request(ChannelPid, ChannelId, Type, Data, true, From, D0),
-    %% Note reply to channel will happen later when reply is recived from peer on the socket
-    start_channel_request_timer(ChannelId, From, Timeout),
-    {keep_state, cache_request_idle_timer_check(D)};
+    case handle_request(ChannelPid, ChannelId, Type, Data, true, From, D0) of
+        {error,Error} ->
+            {keep_state, D0, {reply,From,{error,Error}}};
+        D ->
+            %% Note reply to channel will happen later when reply is recived from peer on the socket
+            start_channel_request_timer(ChannelId, From, Timeout),
+            {keep_state, cache_request_idle_timer_check(D)}
+    end;
 
 handle_event({call,From}, {request, ChannelId, Type, Data, Timeout}, StateName, D0) 
   when ?CONNECTED(StateName) ->
-    D = handle_request(ChannelId, Type, Data, true, From, D0),
-    %% Note reply to channel will happen later when reply is recived from peer on the socket
-    start_channel_request_timer(ChannelId, From, Timeout),
-    {keep_state, cache_request_idle_timer_check(D)};
+    case handle_request(ChannelId, Type, Data, true, From, D0) of
+        {error,Error} ->
+            {keep_state, D0, {reply,From,{error,Error}}};
+        D ->
+            %% Note reply to channel will happen later when reply is recived from peer on the socket
+            start_channel_request_timer(ChannelId, From, Timeout),
+            {keep_state, cache_request_idle_timer_check(D)}
+    end;
 
 handle_event({call,From}, {data, ChannelId, Type, Data, Timeout}, StateName, D0) 
   when ?CONNECTED(StateName) ->
@@ -1773,21 +1781,31 @@ is_usable_user_pubkey(A, Ssh) ->
 %%%----------------------------------------------------------------
 handle_request(ChannelPid, ChannelId, Type, Data, WantReply, From, D) ->
     case ssh_channel:cache_lookup(cache(D), ChannelId) of
-	#channel{remote_id = Id} = Channel ->
+	#channel{remote_id = Id,
+                 sent_close = false} = Channel ->
 	    update_sys(cache(D), Channel, Type, ChannelPid),
 	    send_msg(ssh_connection:channel_request_msg(Id, Type, WantReply, Data),
 		     add_request(WantReply, ChannelId, From, D));
-	undefined ->
-	    D
+
+        _ when WantReply==true ->
+            {error,closed};
+
+        _ ->
+            D
     end.
 
 handle_request(ChannelId, Type, Data, WantReply, From, D) ->
     case ssh_channel:cache_lookup(cache(D), ChannelId) of
-	#channel{remote_id = Id} ->
+	#channel{remote_id = Id,
+                 sent_close = false} ->
 	    send_msg(ssh_connection:channel_request_msg(Id, Type, WantReply, Data),
 		     add_request(WantReply, ChannelId, From, D));
-	undefined ->
-	    D
+
+	_ when WantReply==true ->
+            {error,closed};
+        
+        _ ->
+            D
     end.
 
 %%%----------------------------------------------------------------
diff --git a/lib/ssh/test/ssh_connection_SUITE.erl b/lib/ssh/test/ssh_connection_SUITE.erl
index b818a7f45d..9587c0c251 100644
--- a/lib/ssh/test/ssh_connection_SUITE.erl
+++ b/lib/ssh/test/ssh_connection_SUITE.erl
@@ -897,11 +897,22 @@ start_subsystem_on_closed_channel(Config) ->
 						      {user_interaction, false},
 						      {user_dir, UserDir}]),
 
-    {ok, ChannelId} = ssh_connection:session_channel(ConnectionRef, infinity),
 
-    ok = ssh_connection:close(ConnectionRef, ChannelId),
+    {ok, ChannelId1} = ssh_connection:session_channel(ConnectionRef, infinity),
+    ok = ssh_connection:close(ConnectionRef, ChannelId1),
+    {error, closed} = ssh_connection:ptty_alloc(ConnectionRef, ChannelId1, []),
+    {error, closed} = ssh_connection:subsystem(ConnectionRef, ChannelId1, "echo_n", 5000),
+    {error, closed} = ssh_connection:exec(ConnectionRef, ChannelId1, "testing1.\n", 5000),
+    {error, closed} = ssh_connection:send(ConnectionRef, ChannelId1, "exit().\n", 5000),
 
-    {error, closed} = ssh_connection:subsystem(ConnectionRef, ChannelId, "echo_n", infinity),
+    %% Test that there could be a gap between close and an operation (Bugfix OTP-14939):
+    {ok, ChannelId2} = ssh_connection:session_channel(ConnectionRef, infinity),
+    ok = ssh_connection:close(ConnectionRef, ChannelId2),
+    timer:sleep(2000),
+    {error, closed} = ssh_connection:ptty_alloc(ConnectionRef, ChannelId2, []),
+    {error, closed} = ssh_connection:subsystem(ConnectionRef, ChannelId2, "echo_n", 5000),
+    {error, closed} = ssh_connection:exec(ConnectionRef, ChannelId2, "testing1.\n", 5000),
+    {error, closed} = ssh_connection:send(ConnectionRef, ChannelId2, "exit().\n", 5000),
 
     ssh:close(ConnectionRef),
     ssh:stop_daemon(Pid).