diff options
Diffstat (limited to 'lib/kernel/src/os.erl')
| -rw-r--r-- | lib/kernel/src/os.erl | 95 |
1 files changed, 74 insertions, 21 deletions
diff --git a/lib/kernel/src/os.erl b/lib/kernel/src/os.erl index f0ad26b1f2..0250783632 100644 --- a/lib/kernel/src/os.erl +++ b/lib/kernel/src/os.erl @@ -1,7 +1,7 @@ %% %% %CopyrightBegin% %% -%% Copyright Ericsson AB 1997-2016. All Rights Reserved. +%% Copyright Ericsson AB 1997-2017. All Rights Reserved. %% %% Licensed under the Apache License, Version 2.0 (the "License"); %% you may not use this file except in compliance with the License. @@ -29,7 +29,7 @@ -export([getenv/0, getenv/1, getenv/2, getpid/0, perf_counter/0, perf_counter/1, - putenv/2, system_time/0, system_time/1, + putenv/2, set_signal/2, system_time/0, system_time/1, timestamp/0, unsetenv/1]). -spec getenv() -> [string()]. @@ -104,6 +104,15 @@ timestamp() -> unsetenv(_) -> erlang:nif_error(undef). +-spec set_signal(Signal, Option) -> 'ok' when + Signal :: 'sighup' | 'sigquit' | 'sigabrt' | 'sigalrm' | + 'sigterm' | 'sigusr1' | 'sigusr2' | 'sigchld' | + 'sigstop' | 'sigtstp', + Option :: 'default' | 'handle' | 'ignore'. + +set_signal(_Signal, _Option) -> + erlang:nif_error(undef). + %%% End of BIFs -spec type() -> {Osfamily, Osname} when @@ -226,11 +235,13 @@ extensions() -> Command :: atom() | io_lib:chars(). cmd(Cmd) -> validate(Cmd), - {SpawnCmd, SpawnOpts, SpawnInput} = mk_cmd(os:type(), Cmd), + {SpawnCmd, SpawnOpts, SpawnInput, Eot} = mk_cmd(os:type(), Cmd), Port = open_port({spawn, SpawnCmd}, [binary, stderr_to_stdout, - stream, in, eof, hide | SpawnOpts]), + stream, in, hide | SpawnOpts]), + MonRef = erlang:monitor(port, Port), true = port_command(Port, SpawnInput), - Bytes = get_data(Port, []), + Bytes = get_data(Port, MonRef, Eot, []), + demonitor(MonRef, [flush]), String = unicode:characters_to_list(Bytes), if %% Convert to unicode list if possible otherwise return bytes is_list(String) -> String; @@ -243,7 +254,7 @@ mk_cmd({win32,Wtype}, Cmd) -> {false,_} -> lists:concat(["cmd /c", Cmd]); {Cspec,_} -> lists:concat([Cspec," /c",Cmd]) end, - {Command, [], []}; + {Command, [], [], <<>>}; mk_cmd(OsType,Cmd) when is_atom(Cmd) -> mk_cmd(OsType, atom_to_list(Cmd)); mk_cmd(_,Cmd) -> @@ -252,7 +263,20 @@ mk_cmd(_,Cmd) -> {"/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"]}. + %% + %% The </dev/null closes stdin, which means that programs + %% that use a closed stdin as an termination indicator works. + %% An example of such a program is 'more'. + %% + %% The "echo ^D" is used to indicate that the program has executed + %% and we should return any output we have gotten. We cannot use + %% termination of the child or closing of stdin/stdout as then + %% starting background jobs from os:cmd will block os:cmd. + %% + %% I tried changing this to be "better", but got bombarded with + %% backwards incompatibility bug reports, so leave this as it is. + ["(", unicode:characters_to_binary(Cmd), "\n) </dev/null; echo \"\^D\"\n"], + <<$\^D>>}. validate(Atom) when is_atom(Atom) -> ok; @@ -267,21 +291,50 @@ validate1([List|Rest]) when is_list(List) -> validate1([]) -> ok. -get_data(Port, Sofar) -> +get_data(Port, MonRef, Eot, Sofar) -> receive {Port, {data, Bytes}} -> - get_data(Port, [Sofar,Bytes]); - {Port, eof} -> - Port ! {self(), close}, - receive - {Port, closed} -> - true - end, - receive - {'EXIT', Port, _} -> - ok - after 1 -> % force context switch - ok - end, + case eot(Bytes, Eot) of + more -> + get_data(Port, MonRef, Eot, [Sofar,Bytes]); + Last -> + catch port_close(Port), + flush_until_down(Port, MonRef), + iolist_to_binary([Sofar, Last]) + end; + {'DOWN', MonRef, _, _, _} -> + flush_exit(Port), iolist_to_binary(Sofar) end. + +eot(_Bs, <<>>) -> + more; +eot(Bs, Eot) -> + case binary:match(Bs, Eot) of + nomatch -> more; + {Pos, _} -> + binary:part(Bs,{0, Pos}) + end. + +%% When port_close returns we know that all the +%% messages sent have been sent and that the +%% DOWN message is after them all. +flush_until_down(Port, MonRef) -> + receive + {Port, {data, _Bytes}} -> + flush_until_down(Port, MonRef); + {'DOWN', MonRef, _, _, _} -> + flush_exit(Port) + end. + +%% The exit signal is always delivered before +%% the down signal, so we can be sure that if there +%% was an exit message sent, it will be in the +%% mailbox now. +flush_exit(Port) -> + receive + {'EXIT', Port, _} -> + ok + after 0 -> + ok + end. |