From 8ed0d75c186d9da24bd6cfb85732487b17a3b054 Mon Sep 17 00:00:00 2001
From: Sverker Eriksson <sverker@erlang.org>
Date: Thu, 23 Nov 2017 15:05:34 +0100
Subject: erts: Fix erlang:monitor toward c-nodes

by suppressing DOP_MONITOR_P, DOP_MONITOR_P_EXIT and DOP_DEMONITOR_P
if not supported by the remote node.

In 17e198d6ee60f7dec9abfed272cf4226aea44535
I changed the behavior of erlang:monitor
to not raise badarg for c-nodes but instead create
a monitor to only supervise the connection.

But I forgot to prevent DOP_MONITOR_P and friends from being
sent to the node that does not expect them.

Note: We test both DFLAG_DIST_MONITOR and DFLAG_DIST_MONITOR_NAME
      for the node to support process monitoring. This is because
      erl_interface is buggy as it sets DFLAG_DIST_MONITOR without
      really supporting it.
ToDo: Should erl_interface stop setting DFLAG_DIST_MONITOR
      or should we change the meaning of these flags?
---
 lib/erl_interface/test/ei_accept_SUITE.erl         | 51 +++++++++++++++++++++-
 .../test/ei_accept_SUITE_data/ei_accept_test.c     |  2 +-
 lib/erl_interface/test/runner.erl                  |  7 ++-
 3 files changed, 56 insertions(+), 4 deletions(-)

(limited to 'lib/erl_interface')

diff --git a/lib/erl_interface/test/ei_accept_SUITE.erl b/lib/erl_interface/test/ei_accept_SUITE.erl
index 16eb0901ef..6676e73e21 100644
--- a/lib/erl_interface/test/ei_accept_SUITE.erl
+++ b/lib/erl_interface/test/ei_accept_SUITE.erl
@@ -25,7 +25,8 @@
 -include("ei_accept_SUITE_data/ei_accept_test_cases.hrl").
 
 -export([all/0, suite/0,
-         ei_accept/1, ei_threaded_accept/1]).
+         ei_accept/1, ei_threaded_accept/1,
+         monitor_ei_process/1]).
 
 -import(runner, [get_term/1,send_term/2]).
 
@@ -34,7 +35,8 @@ suite() ->
      {timetrap, {seconds, 30}}].
 
 all() -> 
-    [ei_accept, ei_threaded_accept].
+    [ei_accept, ei_threaded_accept,
+     monitor_ei_process].
 
 ei_accept(Config) when is_list(Config) ->
     P = runner:start(?interpret),
@@ -58,6 +60,7 @@ ei_accept(Config) when is_list(Config) ->
     Port = 6543,
     {ok, ListenFd} = ei_publish(P, Port),
     {any, EINode} ! TermToSend,
+
     {ok, Fd, _Node} = ei_accept(P, ListenFd),
     Got1 = ei_receive(P, Fd),
 
@@ -85,6 +88,41 @@ ei_threaded_accept(Config) when is_list(Config) ->
     [receive I -> ok end || I <- lists:seq(0, N-1) ],
     ok.
 
+
+%% Test erlang:monitor toward erl_interface "processes"
+monitor_ei_process(Config) when is_list(Config) ->
+    P = runner:start(?interpret),
+    0 = ei_connect_init(P, 42, erlang:get_cookie(), 0),
+
+    Myname = hd(tl(string:tokens(atom_to_list(node()), "@"))),
+    io:format("Myname ~p ~n",  [Myname]),
+    EINode = list_to_atom("c42@"++Myname),
+    io:format("EINode ~p ~n",  [EINode]),
+
+    Self = self(),
+    Port = 6543,
+    {ok, ListenFd} = ei_publish(P, Port),
+    MRef1 = erlang:monitor(process, {any, EINode}),
+    {any, EINode} ! hello,
+
+    {ok, Fd, _Node} = ei_accept(P, ListenFd),
+    hello = ei_receive(P, Fd),
+
+    %% Again, now on an established connection.
+    MRef2 = erlang:monitor(process, {any, EINode}),
+    {any, EINode} ! hello,
+    hello = ei_receive(P, Fd),
+
+    ok = receive M -> M after 0 -> ok end,
+
+    runner:finish(P),
+
+    [{'DOWN', MRef1, process, {any, EINode}, noconnection},
+     {'DOWN', MRef2, process, {any, EINode}, noconnection}
+    ] = lists:sort(flush(2, 1000)),
+
+    ok.
+
 waitfornode(String,0) ->
     io:format("~s never published itself.~n",[String]),
     false;
@@ -156,3 +194,12 @@ ei_receive(P, Fd) ->
 
 send_command(P, Name, Args) ->
     runner:send_term(P, {Name,list_to_tuple(Args)}).
+
+flush(0, Timeout) ->
+    flush(1, Timeout div 10);
+flush(Expected, Timeout) ->
+    receive M ->
+            [M | flush(Expected-1, Timeout)]
+    after Timeout ->
+            []
+    end.
diff --git a/lib/erl_interface/test/ei_accept_SUITE_data/ei_accept_test.c b/lib/erl_interface/test/ei_accept_SUITE_data/ei_accept_test.c
index 2355192cc2..2b62d7c3a4 100644
--- a/lib/erl_interface/test/ei_accept_SUITE_data/ei_accept_test.c
+++ b/lib/erl_interface/test/ei_accept_SUITE_data/ei_accept_test.c
@@ -224,7 +224,7 @@ static void cmd_ei_receive(char* buf, int len)
 	if (got == ERL_TICK)
 	    continue;
 	if (got == ERL_ERROR)
-	    fail("ei_xreceive_msg");
+	    fail1("ei_xreceive_msg, got==%d", got);
 	break;
     }
     index = 1;
diff --git a/lib/erl_interface/test/runner.erl b/lib/erl_interface/test/runner.erl
index 1084eec2a3..cbdeb3c8a9 100644
--- a/lib/erl_interface/test/runner.erl
+++ b/lib/erl_interface/test/runner.erl
@@ -67,7 +67,12 @@ start({Prog, Tc}) when is_list(Prog), is_integer(Tc) ->
 
 finish(Port) when is_port(Port) ->
     send_eot(Port),
-    recv_eot(Port).
+    ok = recv_eot(Port),
+    0 = receive
+            {Port,{exit_status,Status}} ->
+                Status
+        end,
+    ok.
 
 %% Sends an Erlang term to a C program.
 
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