aboutsummaryrefslogtreecommitdiffstats
path: root/lib/kernel/src/os.erl
diff options
context:
space:
mode:
Diffstat (limited to 'lib/kernel/src/os.erl')
-rw-r--r--lib/kernel/src/os.erl95
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.