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authorJohn Högberg <[email protected]>2019-05-07 11:39:34 +0200
committerJohn Högberg <[email protected]>2019-05-07 14:22:36 +0200
commit4df8cf1f67a12d2c730e85ab4de64b6fd7557050 (patch)
treeb737b8be2a5c913f2a4766b34a7c23ab7ae3a986 /lib/kernel/src/user_drv.erl
parent0e10a805bde0f1ce8ba9282660aaa2fd1e01fc81 (diff)
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kernel: Force synchronous port_commands in user/user_drv
Banging data to a local port was always synchronous prior to Erlang/OTP R16, and these modules relied on that behavior to report that data had successfully been enqueued on the stdout port. This would cause data to be silently dropped if the command didn't run synchronously and the emulator halted before the port received the data. This was fairly rare in practice, but could be seen from time to time on Windows with escripts that ended with a call to io:format/2, such as the one used by the escript_SUITE:create_and_extract test. This is a minimal band-aid to make things reliable again. A more complete fix would add explicit synchronization with the port.
Diffstat (limited to 'lib/kernel/src/user_drv.erl')
-rw-r--r--lib/kernel/src/user_drv.erl37
1 files changed, 16 insertions, 21 deletions
diff --git a/lib/kernel/src/user_drv.erl b/lib/kernel/src/user_drv.erl
index 69ff8e7971..644aa752b6 100644
--- a/lib/kernel/src/user_drv.erl
+++ b/lib/kernel/src/user_drv.erl
@@ -543,19 +543,14 @@ set_unicode_state(Iport, Bool) ->
%% io_request(Request, InPort, OutPort)
%% io_requests(Requests, InPort, OutPort)
%% Note: InPort is unused.
-
-io_request(Request, Iport, Oport) ->
- try io_command(Request) of
- {command,_} = Command ->
- Oport ! {self(),Command},
- ok;
- {Command,Reply} ->
- Oport ! {self(),Command},
- Reply
- catch
- {requests,Rs} ->
- io_requests(Rs, Iport, Oport);
- _ ->
+io_request({requests,Rs}, Iport, Oport) ->
+ io_requests(Rs, Iport, Oport);
+io_request(Request, _Iport, Oport) ->
+ case io_command(Request) of
+ {Data, Reply} ->
+ true = port_command(Oport, Data),
+ Reply;
+ unhandled ->
ok
end.
@@ -575,19 +570,19 @@ put_int16(N, Tail) ->
%% to the console before the vm stops when calling erlang:halt(integer()).
-dialyzer({no_improper_lists, io_command/1}).
io_command({put_chars_sync, unicode,Cs,Reply}) ->
- {{command,[?OP_PUTC_SYNC|unicode:characters_to_binary(Cs,utf8)]},Reply};
+ {[?OP_PUTC_SYNC|unicode:characters_to_binary(Cs,utf8)], Reply};
io_command({put_chars, unicode,Cs}) ->
- {command,[?OP_PUTC|unicode:characters_to_binary(Cs,utf8)]};
+ {[?OP_PUTC|unicode:characters_to_binary(Cs,utf8)], ok};
io_command({move_rel,N}) ->
- {command,[?OP_MOVE|put_int16(N, [])]};
+ {[?OP_MOVE|put_int16(N, [])], ok};
io_command({insert_chars,unicode,Cs}) ->
- {command,[?OP_INSC|unicode:characters_to_binary(Cs,utf8)]};
+ {[?OP_INSC|unicode:characters_to_binary(Cs,utf8)], ok};
io_command({delete_chars,N}) ->
- {command,[?OP_DELC|put_int16(N, [])]};
+ {[?OP_DELC|put_int16(N, [])], ok};
io_command(beep) ->
- {command,[?OP_BEEP]};
-io_command(Else) ->
- throw(Else).
+ {[?OP_BEEP], ok};
+io_command(_) ->
+ unhandled.
%% gr_new()
%% gr_get_num(Group, Index)