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-rw-r--r--lib/kernel/src/os.erl41
1 files changed, 27 insertions, 14 deletions
diff --git a/lib/kernel/src/os.erl b/lib/kernel/src/os.erl
index fbc046c8f9..1e9db80058 100644
--- a/lib/kernel/src/os.erl
+++ b/lib/kernel/src/os.erl
@@ -21,11 +21,11 @@
%% Provides a common operating system interface.
--export([type/0, version/0, cmd/1, find_executable/1, find_executable/2]).
+-export([type/0, version/0, cmd/1, cmd/2, find_executable/1, find_executable/2]).
-include("file.hrl").
--export_type([env_var_name/0, env_var_value/0, env_var_name_value/0, command_input/0]).
+-export_type([env_var_name/0, env_var_value/0, env_var_name_value/0]).
-export([getenv/0, getenv/1, getenv/2, putenv/2, unsetenv/1]).
@@ -35,14 +35,17 @@
perf_counter/1, set_env_var/2, set_signal/2, system_time/0,
system_time/1, timestamp/0, unset_env_var/1]).
+-type os_command() :: atom() | io_lib:chars().
+-type os_command_opts() :: #{ max_size => non_neg_integer() | infinity }.
+
+-export_type([os_command/0, os_command_opts/0]).
+
-type env_var_name() :: nonempty_string().
-type env_var_value() :: string().
-type env_var_name_value() :: nonempty_string().
--type command_input() :: atom() | io_lib:chars().
-
-spec list_env_vars() -> [{env_var_name(), env_var_value()}].
list_env_vars() ->
erlang:nif_error(undef).
@@ -260,14 +263,20 @@ extensions() ->
%% Executes the given command in the default shell for the operating system.
-spec cmd(Command) -> string() when
- Command :: os:command_input().
+ Command :: os_command().
cmd(Cmd) ->
+ cmd(Cmd, #{ }).
+
+-spec cmd(Command, Options) -> string() when
+ Command :: os_command(),
+ Options :: os_command_opts().
+cmd(Cmd, Opts) ->
{SpawnCmd, SpawnOpts, SpawnInput, Eot} = mk_cmd(os:type(), validate(Cmd)),
Port = open_port({spawn, SpawnCmd}, [binary, stderr_to_stdout,
stream, in, hide | SpawnOpts]),
MonRef = erlang:monitor(port, Port),
true = port_command(Port, SpawnInput),
- Bytes = get_data(Port, MonRef, Eot, []),
+ Bytes = get_data(Port, MonRef, Eot, [], 0, maps:get(max_size, Opts, infinity)),
demonitor(MonRef, [flush]),
String = unicode:characters_to_list(Bytes),
if %% Convert to unicode list if possible otherwise return bytes
@@ -332,12 +341,13 @@ validate2([List|Rest]) when is_list(List) ->
validate2(List),
validate2(Rest).
-get_data(Port, MonRef, Eot, Sofar) ->
+get_data(Port, MonRef, Eot, Sofar, Size, Max) ->
receive
{Port, {data, Bytes}} ->
- case eot(Bytes, Eot) of
+ case eot(Bytes, Eot, Size, Max) of
more ->
- get_data(Port, MonRef, Eot, [Sofar,Bytes]);
+ get_data(Port, MonRef, Eot, [Sofar, Bytes],
+ Size + byte_size(Bytes), Max);
Last ->
catch port_close(Port),
flush_until_down(Port, MonRef),
@@ -348,13 +358,16 @@ get_data(Port, MonRef, Eot, Sofar) ->
iolist_to_binary(Sofar)
end.
-eot(_Bs, <<>>) ->
+eot(_Bs, <<>>, _Size, _Max) ->
more;
-eot(Bs, Eot) ->
+eot(Bs, Eot, Size, Max) ->
case binary:match(Bs, Eot) of
- nomatch -> more;
- {Pos, _} ->
- binary:part(Bs,{0, Pos})
+ nomatch when Size + byte_size(Bs) < Max ->
+ more;
+ {Pos, _} when Size + Pos < Max ->
+ binary:part(Bs,{0, Pos});
+ _ ->
+ binary:part(Bs,{0, Max - Size})
end.
%% When port_close returns we know that all the