Extend erlang:port_info/1,2 to show the OS pid of a spawned process

When spawning OS (unix) processes with erlang:open_port, store the
resulting unix pid so that it can be queried later on using
erlang:port_info/1,2.

1 files changed, 27 insertions, 1 deletions

diff --git a/erts/emulator/test/port_bif_SUITE.erl b/erts/emulator/test/port_bif_SUITE.erl
index d9c82aba0e..f4ba502be5 100644
--- a/erts/emulator/test/port_bif_SUITE.erl
+++ b/erts/emulator/test/port_bif_SUITE.erl
@@ -24,6 +24,7 @@
 	 init_per_group/2,end_per_group/2, command/1,
 	 command_e_1/1, command_e_2/1, command_e_3/1, command_e_4/1,
 	 port_info1/1, port_info2/1,
+	 port_info_os_pid/1,
 	 connect/1, control/1, echo_to_busy/1]).
 
 -export([do_command_e_1/1, do_command_e_2/1, do_command_e_4/1]).
@@ -41,7 +42,7 @@ all() ->
 groups() -> 
     [{command_e, [],
       [command_e_1, command_e_2, command_e_3, command_e_4]},
-     {port_info, [], [port_info1, port_info2]}].
+     {port_info, [], [port_info1, port_info2, port_info_os_pid]}].
 
 init_per_suite(Config) ->
     Config.
@@ -196,6 +197,7 @@ port_info1(Config) when is_list(Config) ->
     ?line {value,{connected,_}}=lists:keysearch(connected, 1, A),
     ?line {value,{input,0}}=lists:keysearch(input, 1, A),
     ?line {value,{output,0}}=lists:keysearch(output, 1, A),
+    ?line {value,{os_pid,undefined}}=lists:keysearch(os_pid, 1, A),  % linked-in driver doesn't have a OS pid
     ?line true=erlang:port_close(P),
     ok.
 
@@ -215,6 +217,7 @@ port_info2(Config) when is_list(Config) ->
     ?line {connected, Me} = erlang:port_info(P, connected),
     ?line {input, 0}=erlang:port_info(P, input),
     ?line {output,0}=erlang:port_info(P, output),
+    ?line {os_pid, undefined}=erlang:port_info(P, os_pid),  % linked-in driver doesn't have a OS pid
 
     ?line erlang:port_control(P, $i, "abc"),
     ?line receive
@@ -229,6 +232,29 @@ port_info2(Config) when is_list(Config) ->
     ?line true = erlang:port_close(P),
     ok.
 
+%% Tests the port_info/1,2 os_pid option BIF
+port_info_os_pid(Config) when is_list(Config) ->
+    case os:type() of
+	{unix,_} ->
+	    do_port_info_os_pid();
+	_ ->
+	    {skip,"Only on Unix."}
+    end.
+
+do_port_info_os_pid() ->
+    ?line P = open_port({spawn, "echo $$"}, [eof]),
+    ?line A = erlang:port_info(P),
+    ?line {os_pid, InfoOSPid} = erlang:port_info(P, os_pid),
+    ?line EchoPidStr = receive
+	    {P, {data, EchoPidStr0}} -> EchoPidStr0
+	    after 10000 -> ?line test_server:fail(timeout)
+    end,
+    ?line {ok, [EchoPid], []} = io_lib:fread("~u\n", EchoPidStr),
+    ?line {value,{os_pid, InfoOSPid}}=lists:keysearch(os_pid, 1, A),
+    ?line EchoPid = InfoOSPid,
+    ?line true = erlang:port_close(P),
+    ok.
+
 output_test(_, _, Input, Output) when Output > 16#1fffffff ->
     io:format("~p bytes received\n", [Input]);
 output_test(P, Bin, Input0, Output0) ->