From 48083e54b502afb2768066394074d29423162dc8 Mon Sep 17 00:00:00 2001 From: Lukas Larsson Date: Thu, 26 Jun 2014 18:55:47 +0200 Subject: kernel,ssh: Add synchronous user_drv protocol Added a put_chars_sync to the protocol that can be used to talk to user_drv and made group use it. This is needed in order to guarantee that bytes has been pushed to the tty port when doing something like this: io:format("halting\n"),erlang:halt(0). Before this change the halting message could be lost in the message queue of the user_drv process, this is no longer possible. This commit also fixes ssh_cli as that plugs itself in as a user_drv process. OTP-12240 --- lib/kernel/src/user_drv.erl | 136 ++++++++++++++++++++++++++++++-------------- 1 file changed, 92 insertions(+), 44 deletions(-) (limited to 'lib/kernel/src/user_drv.erl') diff --git a/lib/kernel/src/user_drv.erl b/lib/kernel/src/user_drv.erl index a91c23539d..79f80f6604 100644 --- a/lib/kernel/src/user_drv.erl +++ b/lib/kernel/src/user_drv.erl @@ -29,6 +29,7 @@ -define(OP_INSC,2). -define(OP_DELC,3). -define(OP_BEEP,4). +-define(OP_PUTC_SYNC,5). % Control op -define(CTRL_OP_GET_WINSIZE,100). -define(CTRL_OP_GET_UNICODE_STATE,101). @@ -133,7 +134,7 @@ server1(Iport, Oport, Shell) -> [erlang:system_info(system_version)]))}, Iport, Oport), %% Enter the server loop. - server_loop(Iport, Oport, Curr, User, Gr). + server_loop(Iport, Oport, Curr, User, Gr, queue:new()). rem_sh_opts(Node) -> [{expand_fun,fun(B)-> rpc:call(Node,edlin_expand,expand,[B]) end}]. @@ -158,42 +159,46 @@ start_user() -> User end. -server_loop(Iport, Oport, User, Gr) -> +server_loop(Iport, Oport, User, Gr, IOQueue) -> Curr = gr_cur_pid(Gr), put(current_group, Curr), - server_loop(Iport, Oport, Curr, User, Gr). + server_loop(Iport, Oport, Curr, User, Gr, IOQueue). -server_loop(Iport, Oport, Curr, User, Gr) -> +server_loop(Iport, Oport, Curr, User, Gr, IOQueue) -> receive {Iport,{data,Bs}} -> BsBin = list_to_binary(Bs), Unicode = unicode:characters_to_list(BsBin,utf8), - port_bytes(Unicode, Iport, Oport, Curr, User, Gr); + port_bytes(Unicode, Iport, Oport, Curr, User, Gr, IOQueue); {Iport,eof} -> Curr ! {self(),eof}, - server_loop(Iport, Oport, Curr, User, Gr); - {User,Req} -> % never block from user! - io_request(Req, Iport, Oport), - server_loop(Iport, Oport, Curr, User, Gr); - {Curr,tty_geometry} -> - Curr ! {self(),tty_geometry,get_tty_geometry(Iport)}, - server_loop(Iport, Oport, Curr, User, Gr); - {Curr,get_unicode_state} -> - Curr ! {self(),get_unicode_state,get_unicode_state(Iport)}, - server_loop(Iport, Oport, Curr, User, Gr); - {Curr,set_unicode_state, Bool} -> - Curr ! {self(),set_unicode_state,set_unicode_state(Iport,Bool)}, - server_loop(Iport, Oport, Curr, User, Gr); - {Curr,Req} -> - io_request(Req, Iport, Oport), - server_loop(Iport, Oport, Curr, User, Gr); + server_loop(Iport, Oport, Curr, User, Gr, IOQueue); + {User,Req} when element(1,Req) == tty_geometry; + element(1,Req) == get_unicode_state; + element(1,Req) == set_unicode_state -> + %% We ignore these requests from User, could be a bug? + 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,_,_} + NewQ = handle_req(Req, Iport, Oport, IOQueue), + server_loop(Iport, Oport, Curr, User, Gr, NewQ); + {Oport,ok} -> + %% We get this ok from the port, in io_request we store + %% info about where to send reply at head of queue + {{value,{Origin,Reply}},ReplyQ} = queue:out(IOQueue), + Origin ! {reply,Reply}, + NewQ = handle_req(next, Iport, Oport, ReplyQ), + server_loop(Iport, Oport, Curr, User, Gr, NewQ); {'EXIT',Iport,_R} -> - server_loop(Iport, Oport, Curr, User, Gr); + server_loop(Iport, Oport, Curr, User, Gr, IOQueue); {'EXIT',Oport,_R} -> - server_loop(Iport, Oport, Curr, User, Gr); + server_loop(Iport, Oport, Curr, User, Gr, IOQueue); + {'EXIT',User,shutdown} -> % force data to port + server_loop(Iport, Oport, Curr, User, Gr, IOQueue); {'EXIT',User,_R} -> % keep 'user' alive NewU = start_user(), - server_loop(Iport, Oport, Curr, NewU, gr_set_num(Gr, 1, NewU, {})); + server_loop(Iport, Oport, Curr, NewU, gr_set_num(Gr, 1, NewU, {}), IOQueue); {'EXIT',Pid,R} -> % shell and group leader exit case gr_cur_pid(Gr) of Pid when R =/= die , @@ -213,18 +218,51 @@ server_loop(Iport, Oport, Curr, User, Gr) -> {ok,Gr2} = gr_set_cur(gr_set_num(Gr1, Ix, Pid1, {shell,start,Params}), Ix), put(current_group, Pid1), - server_loop(Iport, Oport, Pid1, User, Gr2); + server_loop(Iport, Oport, Pid1, User, Gr2, IOQueue); _ -> % remote shell io_requests([{put_chars,unicode,"(^G to start new job) ***\n"}], Iport, Oport), - server_loop(Iport, Oport, Curr, User, Gr1) + server_loop(Iport, Oport, Curr, User, Gr1, IOQueue) end; _ -> % not current, just remove it - server_loop(Iport, Oport, Curr, User, gr_del_pid(Gr, Pid)) + server_loop(Iport, Oport, Curr, User, gr_del_pid(Gr, Pid), IOQueue) end; _X -> %% Ignore unknown messages. - server_loop(Iport, Oport, Curr, User, Gr) + 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,IOQueue) -> + case queue:out(IOQueue) of + {{value,Next},ExecQ} -> + NewQ = handle_req(Next,Iport,Oport,queue:new()), + queue:join(NewQ,ExecQ); + {empty,_} -> + IOQueue + end; +handle_req(Msg,Iport,Oport,IOQueue) -> + case queue:peek(IOQueue) of + empty -> + {Origin,Req} = Msg, + case io_request(Req, Iport, Oport) of + ok -> IOQueue; + Reply -> + %% Push reply info to front of queue + queue:in_r({Origin,Reply},IOQueue) + end; + _Else -> + %% All requests are queued when we have outstanding sync put_chars + queue:in(Msg,IOQueue) end. %% port_bytes(Bytes, InPort, OutPort, CurrentProcess, UserProcess, Group) @@ -232,34 +270,34 @@ server_loop(Iport, Oport, Curr, User, Gr) -> %% either escape to switch_loop or restart the shell. Otherwise send %% the bytes to Curr. -port_bytes([$\^G|_Bs], Iport, Oport, _Curr, User, Gr) -> - handle_escape(Iport, Oport, User, Gr); +port_bytes([$\^G|_Bs], Iport, Oport, _Curr, User, Gr, IOQueue) -> + handle_escape(Iport, Oport, User, Gr, IOQueue); -port_bytes([$\^C|_Bs], Iport, Oport, Curr, User, Gr) -> - interrupt_shell(Iport, Oport, Curr, User, Gr); +port_bytes([$\^C|_Bs], Iport, Oport, Curr, User, Gr, IOQueue) -> + interrupt_shell(Iport, Oport, Curr, User, Gr, IOQueue); -port_bytes([B], Iport, Oport, Curr, User, Gr) -> +port_bytes([B], Iport, Oport, Curr, User, Gr, IOQueue) -> Curr ! {self(),{data,[B]}}, - server_loop(Iport, Oport, Curr, User, Gr); -port_bytes(Bs, Iport, Oport, Curr, User, Gr) -> + server_loop(Iport, Oport, Curr, User, Gr, IOQueue); +port_bytes(Bs, Iport, Oport, Curr, User, Gr, IOQueue) -> case member($\^G, Bs) of true -> - handle_escape(Iport, Oport, User, Gr); + handle_escape(Iport, Oport, User, Gr, IOQueue); false -> Curr ! {self(),{data,Bs}}, - server_loop(Iport, Oport, Curr, User, Gr) + server_loop(Iport, Oport, Curr, User, Gr, IOQueue) end. -interrupt_shell(Iport, Oport, Curr, User, Gr) -> +interrupt_shell(Iport, Oport, Curr, User, Gr, IOQueue) -> case gr_get_info(Gr, Curr) of undefined -> ok; % unknown _ -> exit(Curr, interrupt) end, - server_loop(Iport, Oport, Curr, User, Gr). + server_loop(Iport, Oport, Curr, User, Gr, IOQueue). -handle_escape(Iport, Oport, User, Gr) -> +handle_escape(Iport, Oport, User, Gr, IOQueue) -> case application:get_env(stdlib, shell_esc) of {ok,abort} -> Pid = gr_cur_pid(Gr), @@ -278,11 +316,11 @@ handle_escape(Iport, Oport, User, Gr) -> Pid1 = group:start(self(), {shell,start,[]}), io_request({put_chars,unicode,"\n"}, Iport, Oport), server_loop(Iport, Oport, User, - gr_add_cur(Gr1, Pid1, {shell,start,[]})); + gr_add_cur(Gr1, Pid1, {shell,start,[]}), IOQueue); _ -> % {ok,jcl} | undefined io_request({put_chars,unicode,"\nUser switch command\n"}, Iport, Oport), - server_loop(Iport, Oport, User, switch_loop(Iport, Oport, Gr)) + server_loop(Iport, Oport, User, switch_loop(Iport, Oport, Gr), IOQueue) end. switch_loop(Iport, Oport, Gr) -> @@ -492,9 +530,12 @@ set_unicode_state(Iport, Bool) -> io_request(Request, Iport, Oport) -> try io_command(Request) of - Command -> + {command,_} = Command -> Oport ! {self(),Command}, - ok + ok; + {Command,Reply} -> + Oport ! {self(),Command}, + Reply catch {requests,Rs} -> io_requests(Rs, Iport, Oport); @@ -511,6 +552,13 @@ io_requests([], _Iport, _Oport) -> put_int16(N, Tail) -> [(N bsr 8)band 255,N band 255|Tail]. +%% When a put_chars_sync command is used, user_drv guarantees that +%% the bytes have been put in the buffer of the port before an acknowledgement +%% is sent back to the process sending the request. This command was added in +%% OTP 18 to make sure that data sent from io:format is actually printed +%% to the console before the vm stops when calling erlang:halt(integer()). +io_command({put_chars_sync, unicode,Cs,Reply}) -> + {{command,[?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)]}; io_command({move_rel,N}) -> -- cgit v1.2.3