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authorLukas Larsson <[email protected]>2014-06-26 18:55:47 +0200
committerLukas Larsson <[email protected]>2014-10-16 17:56:16 +0200
commit48083e54b502afb2768066394074d29423162dc8 (patch)
tree00edbcd4e486ac47a61a701d3f0cc6f2e3004156 /lib/kernel/src/user_drv.erl
parent5ab275d6554f4db877624a152dda90c0e3c4cddc (diff)
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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
Diffstat (limited to 'lib/kernel/src/user_drv.erl')
-rw-r--r--lib/kernel/src/user_drv.erl136
1 files changed, 92 insertions, 44 deletions
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}) ->