diff options
Diffstat (limited to 'lib/kernel')
| -rw-r--r-- | lib/kernel/doc/src/notes.xml | 20 | ||||
| -rw-r--r-- | lib/kernel/doc/src/os.xml | 41 | ||||
| -rw-r--r-- | lib/kernel/src/os.erl | 41 | ||||
| -rw-r--r-- | lib/kernel/test/os_SUITE.erl | 18 | ||||
| -rw-r--r-- | lib/kernel/vsn.mk | 2 |
5 files changed, 98 insertions, 24 deletions
diff --git a/lib/kernel/doc/src/notes.xml b/lib/kernel/doc/src/notes.xml index d7f224c38e..65fe9b9c07 100644 --- a/lib/kernel/doc/src/notes.xml +++ b/lib/kernel/doc/src/notes.xml @@ -31,6 +31,26 @@ </header> <p>This document describes the changes made to the Kernel application.</p> +<section><title>Kernel 5.4.2</title> + + <section><title>Fixed Bugs and Malfunctions</title> + <list> + <item> + <p> + Add <c>os:cmd/2</c> that takes an options map as the + second argument.</p> + <p> + Add <c>max_size</c> as an option to <c>os:cmd/2</c> that + control the maximum size of the result that + <c>os:cmd/2</c> will return.</p> + <p> + Own Id: OTP-14823</p> + </item> + </list> + </section> + +</section> + <section><title>Kernel 5.4.1</title> <section><title>Fixed Bugs and Malfunctions</title> diff --git a/lib/kernel/doc/src/os.xml b/lib/kernel/doc/src/os.xml index c27182ff0b..ef416ed233 100644 --- a/lib/kernel/doc/src/os.xml +++ b/lib/kernel/doc/src/os.xml @@ -103,7 +103,7 @@ </desc> </datatype> <datatype> - <name name="command_input"/> + <name name="os_command"/> <desc> <p>All characters needs to be valid characters on the specific OS using @@ -116,19 +116,31 @@ </p> </desc> </datatype> + <datatype> + <name name="os_command_opts"/> + <desc> + <p>Options for <seealso marker="#cmd/2"><c>os:cmd/2</c></seealso></p> + <taglist> + <tag><c>max_size</c></tag> + <item> + <p>The maximum size of the data returned by the <c>os:cmd</c> call. + See the <seealso marker="#cmd/2"><c>os:cmd/2</c></seealso> + documentation for more details.</p> + </item> + </taglist> + </desc> + </datatype> </datatypes> - + <funcs> <func> <name name="cmd" arity="1"/> + <name name="cmd" arity="2"/> <fsummary>Execute a command in a shell of the target OS.</fsummary> <desc> <p>Executes <c><anno>Command</anno></c> in a command shell of the - target OS, - captures the standard output of the command, and returns this - result as a string. This function is a replacement of - the previous function <c>unix:cmd/1</c>; they are equivalent on a - Unix platform.</p> + target OS, captures the standard output of the command, + and returns this result as a string.</p> <warning><p>Previous implementation used to allow all characters as long as they were integer values greater than or equal to zero. This sometimes lead to unwanted results since null characters @@ -142,6 +154,21 @@ DirOut = os:cmd("dir"), % on Win32 platform</code> called from another program (for example, <c>os:cmd/1</c>) can differ, compared with the standard output of the command when called directly from an OS command shell.</p> + <p><c>os:cmd/2</c> was added in kernel-5.5 (OTP-20.2.1). It makes it + possible to pass an options map as the second argument in order to + control the behaviour of <c>os:cmd</c>. The possible options are: + </p> + <taglist> + <tag><c>max_size</c></tag> + <item> + <p>The maximum size of the data returned by the <c>os:cmd</c> call. + This option is a safety feature that should be used when the command + executed can return a very large, possibly infinite, result.</p> + <code type="none"> +> os:cmd("cat /dev/zero", #{ max_size => 20 }). +[0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0]</code> + </item> + </taglist> </desc> </func> 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 diff --git a/lib/kernel/test/os_SUITE.erl b/lib/kernel/test/os_SUITE.erl index 8056321448..4369b1b0f9 100644 --- a/lib/kernel/test/os_SUITE.erl +++ b/lib/kernel/test/os_SUITE.erl @@ -26,7 +26,8 @@ null_in_command/1, space_in_name/1, bad_command/1, find_executable/1, unix_comment_in_command/1, deep_list_command/1, large_output_command/1, background_command/0, background_command/1, - message_leak/1, close_stdin/0, close_stdin/1, perf_counter_api/1]). + message_leak/1, close_stdin/0, close_stdin/1, max_size_command/1, + perf_counter_api/1]). -include_lib("common_test/include/ct.hrl"). @@ -39,7 +40,7 @@ all() -> space_in_name, bad_command, find_executable, unix_comment_in_command, deep_list_command, large_output_command, background_command, message_leak, - close_stdin, perf_counter_api]. + close_stdin, max_size_command, perf_counter_api]. groups() -> []. @@ -322,6 +323,19 @@ close_stdin(Config) -> "-1" = os:cmd(Fds). +max_size_command(_Config) -> + + Res20 = os:cmd("cat /dev/zero", #{ max_size => 20 }), + 20 = length(Res20), + + Res0 = os:cmd("cat /dev/zero", #{ max_size => 0 }), + 0 = length(Res0), + + Res32768 = os:cmd("cat /dev/zero", #{ max_size => 32768 }), + 32768 = length(Res32768), + + ResHello = os:cmd("echo hello", #{ max_size => 20 }), + 6 = length(ResHello). %% Test that the os:perf_counter api works as expected perf_counter_api(_Config) -> diff --git a/lib/kernel/vsn.mk b/lib/kernel/vsn.mk index 106bda01ca..91261e1d55 100644 --- a/lib/kernel/vsn.mk +++ b/lib/kernel/vsn.mk @@ -1 +1 @@ -KERNEL_VSN = 5.4.1 +KERNEL_VSN = 5.4.2 |