From fb2bd4fad031d87984cfa1715ce28be384478a15 Mon Sep 17 00:00:00 2001 From: Dan Gudmundsson Date: Mon, 28 Aug 2017 17:12:08 +0200 Subject: Always reply to sync requests Otherwise processes doing io could get stuck. See ERL-472. --- lib/kernel/src/user_drv.erl | 31 +++++++++++++++++++------------ 1 file changed, 19 insertions(+), 12 deletions(-) (limited to 'lib') diff --git a/lib/kernel/src/user_drv.erl b/lib/kernel/src/user_drv.erl index b794d4f45e..99ea4210bd 100644 --- a/lib/kernel/src/user_drv.erl +++ b/lib/kernel/src/user_drv.erl @@ -175,6 +175,18 @@ server_loop(Iport, Oport, Curr, User, Gr, {Resp, IOQ} = IOQueue) -> {Iport,eof} -> Curr ! {self(),eof}, server_loop(Iport, Oport, Curr, User, Gr, IOQueue); + + %% We always handle geometry and unicode requests + {Requester,tty_geometry} -> + Requester ! {self(),tty_geometry,get_tty_geometry(Iport)}, + server_loop(Iport, Oport, Curr, User, Gr, IOQueue); + {Requester,get_unicode_state} -> + Requester ! {self(),get_unicode_state,get_unicode_state(Iport)}, + server_loop(Iport, Oport, Curr, User, Gr, IOQueue); + {Requester,set_unicode_state, Bool} -> + Requester ! {self(),set_unicode_state,set_unicode_state(Iport,Bool)}, + server_loop(Iport, Oport, Curr, User, Gr, IOQueue); + Req when element(1,Req) =:= User orelse element(1,Req) =:= Curr, tuple_size(Req) =:= 2 orelse tuple_size(Req) =:= 3 -> %% We match {User|Curr,_}|{User|Curr,_,_} @@ -224,21 +236,16 @@ server_loop(Iport, Oport, Curr, User, Gr, {Resp, IOQ} = IOQueue) -> _ -> % not current, just remove it server_loop(Iport, Oport, Curr, User, gr_del_pid(Gr, Pid), IOQueue) end; + {Requester, {put_chars_sync, _, _, Reply}} -> + %% We need to ack the Req otherwise originating process will hang forever + %% Do discard the output to non visible shells (as was done previously) + Requester ! {reply, Reply}, + server_loop(Iport, Oport, Curr, User, Gr, IOQueue); _X -> - %% Ignore unknown messages. - server_loop(Iport, Oport, Curr, User, Gr, IOQueue) + %% Ignore unknown messages. + server_loop(Iport, Oport, Curr, User, Gr, IOQueue) end. -%% We always handle geometry and unicode requests -handle_req({Curr,tty_geometry},Iport,_Oport,IOQueue) -> - Curr ! {self(),tty_geometry,get_tty_geometry(Iport)}, - IOQueue; -handle_req({Curr,get_unicode_state},Iport,_Oport,IOQueue) -> - Curr ! {self(),get_unicode_state,get_unicode_state(Iport)}, - IOQueue; -handle_req({Curr,set_unicode_state, Bool},Iport,_Oport,IOQueue) -> - Curr ! {self(),set_unicode_state,set_unicode_state(Iport,Bool)}, - IOQueue; handle_req(next,Iport,Oport,{false,IOQ}=IOQueue) -> case queue:out(IOQ) of {empty,_} -> -- cgit v1.2.3