From 200247f972b012ced0c4b2c6611f091af66ebedd Mon Sep 17 00:00:00 2001 From: Lukas Larsson Date: Mon, 14 Sep 2015 11:52:09 +0200 Subject: kernel: Remove cmd server for unix os:cmd Since we no longer to vfork in the emulator there is no need to serialize the os:cmd calls through a central command server. This greatly decreases the complexity of this code and should make it fast+more scalable. OTP-13089 --- lib/kernel/src/os.erl | 191 +++++++------------------------------------------- 1 file changed, 25 insertions(+), 166 deletions(-) (limited to 'lib/kernel/src') diff --git a/lib/kernel/src/os.erl b/lib/kernel/src/os.erl index ffb899e5ca..0022959c11 100644 --- a/lib/kernel/src/os.erl +++ b/lib/kernel/src/os.erl @@ -212,174 +212,33 @@ extensions() -> Command :: atom() | io_lib:chars(). cmd(Cmd) -> validate(Cmd), - Bytes = case type() of - {unix, _} -> - unix_cmd(Cmd); - {win32, Wtype} -> - Command0 = case {os:getenv("COMSPEC"),Wtype} of - {false,windows} -> lists:concat(["command.com /c", Cmd]); - {false,_} -> lists:concat(["cmd /c", Cmd]); - {Cspec,_} -> lists:concat([Cspec," /c",Cmd]) - end, - %% open_port/2 awaits string() in Command, but io_lib:chars() can be - %% deep lists according to io_lib module description. - Command = lists:flatten(Command0), - Port = open_port({spawn, Command}, [stream, in, eof, hide]), - get_data(Port, []) - end, - String = unicode:characters_to_list(list_to_binary(Bytes)), + {SpawnCmd, SpawnOpts, SpawnInput} = mk_cmd(os:type(), Cmd), + Port = open_port({spawn, SpawnCmd}, [binary, stderr_to_stdout, + stream, in, eof, hide | SpawnOpts]), + true = port_command(Port, SpawnInput), + Bytes = get_data(Port, []), + String = unicode:characters_to_list(Bytes), if %% Convert to unicode list if possible otherwise return bytes is_list(String) -> String; - true -> Bytes + true -> binary_to_list(Bytes) end. -unix_cmd(Cmd) -> - Tag = make_ref(), - {Pid,Mref} = erlang:spawn_monitor( - fun() -> - process_flag(trap_exit, true), - Port = start_port(), - erlang:port_command(Port, mk_cmd(Cmd)), - exit({Tag,unix_get_data(Port)}) - end), - receive - {'DOWN',Mref,_,Pid,{Tag,Result}} -> - Result; - {'DOWN',Mref,_,Pid,Reason} -> - exit(Reason) - end. - -%% The -s flag implies that only the positional parameters are set, -%% and the commands are read from standard input. We set the -%% $1 parameter for easy identification of the resident shell. -%% --define(ROOT, "/"). --define(ROOT_ANDROID, "/system"). --define(SHELL, "bin/sh -s unix:cmd 2>&1"). --define(PORT_CREATOR_NAME, os_cmd_port_creator). - -%% -%% Serializing open_port through a process to avoid smp lock contention -%% when many concurrent os:cmd() want to do vfork (OTP-7890). -%% --spec start_port() -> port(). -start_port() -> - Ref = make_ref(), - Request = {Ref,self()}, - {Pid, Mon} = case whereis(?PORT_CREATOR_NAME) of - undefined -> - spawn_monitor(fun() -> - start_port_srv(Request) - end); - P -> - P ! Request, - M = erlang:monitor(process, P), - {P, M} - end, - receive - {Ref, Port} when is_port(Port) -> - erlang:demonitor(Mon, [flush]), - Port; - {Ref, Error} -> - erlang:demonitor(Mon, [flush]), - exit(Error); - {'DOWN', Mon, process, Pid, _Reason} -> - start_port() - end. - -start_port_srv(Request) -> - %% We don't want a group leader of some random application. Use - %% kernel_sup's group leader. - {group_leader, GL} = process_info(whereis(kernel_sup), - group_leader), - true = group_leader(GL, self()), - process_flag(trap_exit, true), - StayAlive = try register(?PORT_CREATOR_NAME, self()) - catch - error:_ -> false - end, - start_port_srv_handle(Request), - case StayAlive of - true -> start_port_srv_loop(); - false -> exiting - end. - -start_port_srv_handle({Ref,Client}) -> - Path = case lists:reverse(erlang:system_info(system_architecture)) of - % androideabi - "ibaediordna" ++ _ -> filename:join([?ROOT_ANDROID, ?SHELL]); - _ -> filename:join([?ROOT, ?SHELL]) - end, - Reply = try open_port({spawn, Path},[stream]) of - Port when is_port(Port) -> - (catch port_connect(Port, Client)), - unlink(Port), - Port - catch - error:Reason -> - {Reason,erlang:get_stacktrace()} - end, - Client ! {Ref,Reply}, - ok. - -start_port_srv_loop() -> - receive - {Ref, Client} = Request when is_reference(Ref), - is_pid(Client) -> - start_port_srv_handle(Request); - _Junk -> - ok - end, - start_port_srv_loop(). - -%% -%% unix_get_data(Port) -> Result -%% -unix_get_data(Port) -> - unix_get_data(Port, []). - -unix_get_data(Port, Sofar) -> - receive - {Port,{data, Bytes}} -> - case eot(Bytes) of - {done, Last} -> - lists:flatten([Sofar|Last]); - more -> - unix_get_data(Port, [Sofar|Bytes]) - end; - {'EXIT', Port, _} -> - lists:flatten(Sofar) - end. - -%% -%% eot(String) -> more | {done, Result} -%% -eot(Bs) -> - eot(Bs, []). - -eot([4| _Bs], As) -> - {done, lists:reverse(As)}; -eot([B| Bs], As) -> - eot(Bs, [B| As]); -eot([], _As) -> - more. - -%% -%% mk_cmd(Cmd) -> {ok, ShellCommandString} | {error, ErrorString} -%% -%% We do not allow any input to Cmd (hence commands that want -%% to read from standard input will return immediately). -%% Standard error is redirected to standard output. -%% -%% We use ^D (= EOT = 4) to mark the end of the stream. -%% -mk_cmd(Cmd) when is_atom(Cmd) -> % backward comp. - mk_cmd(atom_to_list(Cmd)); -mk_cmd(Cmd) -> - %% We insert a new line after the command, in case the command - %% contains a comment character. - [$(, unicode:characters_to_binary(Cmd), "\n) + Command = case {os:getenv("COMSPEC"),Wtype} of + {false,windows} -> lists:concat(["command.com /c", Cmd]); + {false,_} -> lists:concat(["cmd /c", Cmd]); + {Cspec,_} -> lists:concat([Cspec," /c",Cmd]) + end, + {Command, [], []}; +mk_cmd(OsType,Cmd) when is_atom(Cmd) -> + mk_cmd(OsType, atom_to_list(Cmd)); +mk_cmd(_,Cmd) -> + %% Have to send command in like this in order to make sh commands like + %% cd and ulimit available + {"/bin/sh -s unix:cmd", [out], + %% We insert a new line after the command, in case the command + %% contains a comment character. + ["(", unicode:characters_to_binary(Cmd), "\n); exit\n"]}. validate(Atom) when is_atom(Atom) -> ok; @@ -397,7 +256,7 @@ validate1([]) -> get_data(Port, Sofar) -> receive {Port, {data, Bytes}} -> - get_data(Port, [Sofar|Bytes]); + get_data(Port, [Sofar,Bytes]); {Port, eof} -> Port ! {self(), close}, receive @@ -410,5 +269,5 @@ get_data(Port, Sofar) -> after 1 -> % force context switch ok end, - lists:flatten(Sofar) + iolist_to_binary(Sofar) end. -- cgit v1.2.3