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xmpp.chapril.org-ejabberd/src/ejabberd_xmlrpc.erl
Evgeniy Khramtsov fd8e07af47 Get rid of ejabberd.hrl header
The header consisted of too many unrelated stuff and macros misuse.
Some stuff is moved into scram.hrl and type_compat.hrl.
All macros have been replaced with the corresponding function calls.

TODO: probably type_compat.hrl is not even needed anymore since
we support only Erlang >= OTP 17.5
2018-06-14 14:00:47 +03:00

592 lines
22 KiB
Erlang

%%%----------------------------------------------------------------------
%%% File : ejabberd_xmlrpc.erl
%%% Author : Badlop <badlop@process-one.net>
%%% Purpose : XML-RPC server that frontends ejabberd commands
%%% Created : 21 Aug 2007 by Badlop <badlop@process-one.net>
%%%
%%%
%%% ejabberd, Copyright (C) 2002-2018 ProcessOne
%%%
%%% This program is free software; you can redistribute it and/or
%%% modify it under the terms of the GNU General Public License as
%%% published by the Free Software Foundation; either version 2 of the
%%% License, or (at your option) any later version.
%%%
%%% This program is distributed in the hope that it will be useful,
%%% but WITHOUT ANY WARRANTY; without even the implied warranty of
%%% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
%%% General Public License for more details.
%%%
%%% You should have received a copy of the GNU General Public License along
%%% with this program; if not, write to the Free Software Foundation, Inc.,
%%% 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
%%%
%%%----------------------------------------------------------------------
%%% TODO: Implement a command in ejabberdctl 'help COMMAND LANGUAGE' that shows
%%% a coding example to call that command in a specific language (python, php).
%%% TODO: Remove support for plaintext password
%%% TODO: commands strings should be strings without ~n
-module(ejabberd_xmlrpc).
-author('badlop@process-one.net').
-export([start/2, handler/2, process/2, socket_type/0,
transform_listen_option/2, listen_opt_type/1]).
-include("logger.hrl").
-include("ejabberd_http.hrl").
-include("mod_roster.hrl").
-include("xmpp.hrl").
-record(state,
{access_commands = [] :: list(),
auth = noauth :: noauth | map(),
get_auth = true :: boolean(),
ip :: inet:ip_address()}).
%% Test:
%% xmlrpc:call({127, 0, 0, 1}, 4560, "/", {call, take_integer, [{struct, [{thisinteger, 5}]}]}).
%% {ok,{response,[{struct,[{zero,0}]}]}}
%%
%% xmlrpc:call({127, 0, 0, 1}, 4560, "/", {call, echo_string, [{struct, [{thisstring, "abcd"}]}]}).
%% {ok,{response,[{struct,[{thatstring,"abcd"}]}]}}
%%
%% xmlrpc:call({127, 0, 0, 1}, 4560, "/", {call, tell_tuple_3integer, [{struct, [{thisstring, "abcd"}]}]}).
%% {ok,{response,
%% [{struct,
%% [{thattuple,
%% {array,
%% [{struct,[{first,123}]},
%% {struct,[{second,456}]},
%% {struct,[{third,789}]}]}}]}]}}
%%
%% xmlrpc:call({127, 0, 0, 1}, 4560, "/", {call, pow, [{struct, [{base, 5}, {exponent, 7}]}]}).
%% {ok,{response,[{struct,[{pow,78125}]}]}}
%%
%% xmlrpc:call({127, 0, 0, 1}, 4560, "/", {call, seq, [{struct, [{from, 3}, {to, 7}]}]}).
%% {ok,{response,[{array,[{struct,[{intermediate,3}]},
%% {struct,[{intermediate,4}]},
%% {struct,[{intermediate,5}]},
%% {struct,[{intermediate,6}]},
%% {struct,[{intermediate,7}]}]}]}}
%%
%% xmlrpc:call({127, 0, 0, 1}, 4560, "/", {call, substrs, [{struct, [{word, "abcd"}]}]}).
%% NO:
%% {ok,{response,[{array,[{struct,[{miniword,"a"}]},
%% {struct,[{miniword,"ab"}]},
%% {struct,[{miniword,"abc"}]},
%% {struct,[{miniword,"abcd"}]}]}]}}
%% {ok,{response,
%% [{struct,
%% [{substrings,
%% {array,
%% [{struct,[{miniword,"a"}]},
%% {struct,[{miniword,"ab"}]},
%% {struct,[{miniword,"abc"}]},
%% {struct,[{miniword,"abcd"}]}]}}]}]}}
%%
%% xmlrpc:call({127, 0, 0, 1}, 4560, "/", {call, splitjid, [{struct, [{jid, "abcd@localhost/work"}]}]}).
%% {ok,{response,
%% [{struct,
%% [{jidparts,
%% {array,
%% [{struct,[{user,"abcd"}]},
%% {struct,[{server,"localhost"}]},
%% {struct,[{resource,"work"}]}]}}]}]}}
%%
%% xmlrpc:call({127, 0, 0, 1}, 4560, "/", {call, echo_integer_string, [{struct, [{thisstring, "abc"}, {thisinteger, 55}]}]}).
%% {ok,{response,
%% [{struct,
%% [{thistuple,
%% {array,
%% [{struct,[{thisinteger,55}]},
%% {struct,[{thisstring,"abc"}]}]}}]}]}}
%%
%%
%% xmlrpc:call({127, 0, 0, 1}, 4560, "/", {call, echo_list_integer, [{struct, [{thislist, {array, [{struct, [{thisinteger, 55}, {thisinteger, 4567}]}]}}]}]}).
%% {ok,{response,
%% [{struct,
%% [{thatlist,
%% {array,
%% [{struct,[{thatinteger,55}]},
%% {struct,[{thatinteger,4567}]}]}}]}]}}
%%
%%
%% xmlrpc:call({127, 0, 0, 1}, 4560, "/", {call, echo_integer_list_string, [{struct, [{thisinteger, 123456}, {thislist, {array, [{struct, [{thisstring, "abc"}, {thisstring, "bobo baba"}]}]}}]}]}).
%% {ok,
%% {response,
%% [{struct,
%% [{thistuple,
%% {array,
%% [{struct,[{thatinteger,123456}]},
%% {struct,
%% [{thatlist,
%% {array,
%% [{struct,[{thatstring,"abc"}]},
%% {struct,[{thatstring,"bobo baba"}]}]}}]}]}}]}]}}
%%
%% xmlrpc:call({127, 0, 0, 1}, 4560, "/", {call, take_tuple_2integer, [{struct, [{thistuple, {array, [{struct, [{thisinteger1, 55}, {thisinteger2, 4567}]}]}}]}]}).
%% {ok,{response,[{struct,[{zero,0}]}]}}
%%
%% xmlrpc:call({127, 0, 0, 1}, 4560, "/", {call, echo_isatils, [{struct,
%% [{thisinteger, 123456990},
%% {thisstring, "This is ISATILS"},
%% {thisatom, "test_isatils"},
%% {thistuple, {array, [{struct, [
%% {listlen, 2},
%% {thislist, {array, [{struct, [
%% {contentstring, "word1"},
%% {contentstring, "word 2"}
%% ]}]}}
%% ]}]}}
%% ]}]}).
%% {ok,{response,
%% [{struct,
%% [{results,
%% {array,
%% [{struct,[{thatinteger,123456990}]},
%% {struct,[{thatstring,"This is ISATILS"}]},
%% {struct,[{thatatom,"test_isatils"}]},
%% {struct,
%% [{thattuple,
%% {array,
%% [{struct,[{listlen,123456990}]},
%% {struct,[{thatlist,...}]}]}}]}]}}]}]}}
%% ecommand doesn't exist:
%% xmlrpc:call({127, 0, 0, 1}, 4560, "/", {call, echo_integer_string2, [{struct, [{thisstring, "abc"}]}]}).
%% {ok,{response,{fault,-1, "Unknown call: {call,echo_integer_string2,[{struct,[{thisstring,\"abc\"}]}]}"}}}
%%
%% Duplicated argument:
%% xmlrpc:call({127, 0, 0, 1}, 4560, "/", {call, echo_integer_string, [{struct, [{thisstring, "abc"}, {thisinteger, 44}, {thisinteger, 55}]}]}).
%% {ok,{response,{fault,-104, "Error -104\nAttribute 'thisinteger' duplicated:\n[{thisstring,\"abc\"},{thisinteger,44},{thisinteger,55}]"}}}
%%
%% Missing argument:
%% xmlrpc:call({127, 0, 0, 1}, 4560, "/", {call, echo_integer_string, [{struct, [{thisstring, "abc"}]}]}).
%% {ok,{response,{fault,-106, "Error -106\nRequired attribute 'thisinteger' not found:\n[{thisstring,\"abc\"}]"}}}
%%
%% Duplicated tuple element:
%% xmlrpc:call({127, 0, 0, 1}, 4560, "/", {call, take_tuple_2integer, [{struct, [{thistuple, {array, [{struct, [{thisinteger1, 55}, {thisinteger1, 66}, {thisinteger2, 4567}]}]}}]}]}).
%% {ok,{response,{fault,-104, "Error -104\nAttribute 'thisinteger1' defined multiple times:\n[{thisinteger1,55},{thisinteger1,66},{thisinteger2,4567}]"}}}
%%
%% Missing element in tuple:
%% xmlrpc:call({127, 0, 0, 1}, 4560, "/", {call, take_tuple_2integer, [{struct, [{thistuple, {array, [{struct, [{thisinteger1, 55}, {thisintegerc, 66}, {thisinteger, 4567}]}]}}]}]}).
%% {ok,{response,{fault,-106, "Error -106\nRequired attribute 'thisinteger2' not found:\n[{thisintegerc,66},{thisinteger,4567}]"}}}
%%
%% The ecommand crashed:
%% xmlrpc:call({127, 0, 0, 1}, 4560, "/", {call, this_crashes, [{struct, []}]}).
%% {ok,{response,{fault,-100, "Error -100\nA problem 'error' occurred executing the command this_crashes with arguments []: badarith"}}}
%% -----------------------------
%% Listener interface
%% -----------------------------
start({gen_tcp = _SockMod, Socket}, Opts) ->
ejabberd_http:start({gen_tcp, Socket}, [{xmlrpc, true}|Opts]).
socket_type() -> raw.
%% -----------------------------
%% HTTP interface
%% -----------------------------
process(_, #request{method = 'POST', data = Data, opts = Opts, ip = {IP, _}}) ->
AccessCommands = proplists:get_value(access_commands, Opts),
GetAuth = true,
State = #state{access_commands = AccessCommands, get_auth = GetAuth, ip = IP},
case fxml_stream:parse_element(Data) of
{error, _} ->
{400, [],
#xmlel{name = <<"h1">>, attrs = [],
children = [{xmlcdata, <<"Malformed XML">>}]}};
El ->
case fxmlrpc:decode(El) of
{error, _} = Err ->
?ERROR_MSG("XML-RPC request ~s failed with reason: ~p",
[Data, Err]),
{400, [],
#xmlel{name = <<"h1">>, attrs = [],
children = [{xmlcdata, <<"Malformed Request">>}]}};
{ok, RPC} ->
?DEBUG("got XML-RPC request: ~p", [RPC]),
{false, Result} = handler(State, RPC),
XML = fxml:element_to_binary(fxmlrpc:encode(Result)),
{200, [{<<"Content-Type">>, <<"text/xml">>}],
<<"<?xml version=\"1.0\"?>", XML/binary>>}
end
end;
process(_, _) ->
{400, [],
#xmlel{name = <<"h1">>, attrs = [],
children = [{xmlcdata, <<"400 Bad Request">>}]}}.
%% -----------------------------
%% Access verification
%% -----------------------------
extract_auth(AuthList) ->
?DEBUG("AUTHLIST ~p", [AuthList]),
try get_attrs([user, server, token], AuthList) of
[U0, S0, T] ->
U = jid:nodeprep(U0),
S = jid:nameprep(S0),
case ejabberd_oauth:check_token(T) of
{ok, {U, S}, Scope} ->
#{usr => {U, S, <<"">>}, oauth_scope => Scope, caller_server => S};
{false, Reason} ->
{error, Reason};
_ ->
{error, not_found}
end
catch
exit:{attribute_not_found, _, _} ->
try get_attrs([user, server, password], AuthList) of
[U0, S0, P] ->
U = jid:nodeprep(U0),
S = jid:nameprep(S0),
case ejabberd_auth:check_password(U, <<"">>, S, P) of
true ->
#{usr => {U, S, <<"">>}, caller_server => S};
false ->
{error, invalid_auth}
end
catch
exit:{attribute_not_found, Attr, _} ->
throw({error, missing_auth_arguments, Attr})
end
end.
%% -----------------------------
%% Handlers
%% -----------------------------
%% Call: Arguments: Returns:
%% .............................
%% Access verification
%% xmlrpc:call({127, 0, 0, 1}, 4560, "/", {call, echothis, [152]}).
%% {ok,{response,{fault,-103, "Error -103\nRequired authentication: {call,echothis,[152]}"}}}
%%
%% xmlrpc:call({127, 0, 0, 1}, 4560, "/", {call, echothis, [{struct, [{user, "badlop"}, {server, "localhost"}, {password, "ada"}]}, 152]}).
%% {ok,{response,{fault,-103,
%% "Error -103\nAuthentication non valid: [{user,\"badlop\"},\n
%% {server,\"localhost\"},\n
%% {password,\"ada\"}]"}}}
%%
%% xmlrpc:call({127, 0, 0, 1}, 4560, "/", {call, echothis, [{struct, [{user, "badlop"}, {server, "localhost"}, {password, "ada90ada"}]}, 152]}).
%% {ok,{response,[152]}}
%%
%% xmlrpc:call({127, 0, 0, 1}, 4560, "/", {call, echothis, [{struct, [{user, "badlop"}, {server, "localhost"}, {password, "79C1574A43BC995F2B145A299EF97277"}]}, 152]}).
%% {ok,{response,[152]}}
handler(#state{get_auth = true, auth = noauth, ip = IP} = State,
{call, Method,
[{struct, AuthList} | Arguments] = AllArgs}) ->
try extract_auth(AuthList) of
{error, invalid_auth} ->
build_fault_response(-118,
"Invalid authentication data",
[]);
{error, not_found} ->
build_fault_response(-118,
"Invalid oauth token",
[]);
{error, expired} ->
build_fault_response(-118,
"Invalid oauth token",
[]);
{error, Value} ->
build_fault_response(-118,
"Invalid authentication data: ~p",
[Value]);
Auth ->
handler(State#state{get_auth = false, auth = Auth#{ip => IP, caller_module => ?MODULE}},
{call, Method, Arguments})
catch
{error, missing_auth_arguments, _Attr} ->
handler(State#state{get_auth = false,
auth = #{ip => IP, caller_module => ?MODULE}},
{call, Method, AllArgs})
end;
%% .............................
%% Debug
%% echothis String String
handler(_State, {call, echothis, [A]}) ->
{false, {response, [A]}};
%% echothisnew struct[{sentence, String}] struct[{repeated, String}]
handler(_State,
{call, echothisnew, [{struct, [{sentence, A}]}]}) ->
{false, {response, [{struct, [{repeated, A}]}]}};
%% multhis struct[{a, Integer}, {b, Integer}] Integer
handler(_State,
{call, multhis, [{struct, [{a, A}, {b, B}]}]}) ->
{false, {response, [A * B]}};
%% multhisnew struct[{a, Integer}, {b, Integer}] struct[{mu, Integer}]
handler(_State,
{call, multhisnew, [{struct, [{a, A}, {b, B}]}]}) ->
{false, {response, [{struct, [{mu, A * B}]}]}};
%% .............................
%% ejabberd commands
handler(State, {call, Command, []}) ->
handler(State, {call, Command, [{struct, []}]});
handler(State,
{call, Command, [{struct, AttrL}]} = Payload) ->
case ejabberd_commands:get_command_format(Command, State#state.auth) of
{error, command_unknown} ->
build_fault_response(-112, "Unknown call: ~p",
[Payload]);
{ArgsF, ResultF} ->
try_do_command(State#state.access_commands,
State#state.auth, Command, AttrL, ArgsF, ResultF)
end;
%% If no other guard matches
handler(_State, Payload) ->
build_fault_response(-112, "Unknown call: ~p",
[Payload]).
%% -----------------------------
%% Command
%% -----------------------------
try_do_command(AccessCommands, Auth, Command, AttrL,
ArgsF, ResultF) ->
try do_command(AccessCommands, Auth, Command, AttrL,
ArgsF, ResultF)
of
{command_result, ResultFormatted} ->
{false, {response, [ResultFormatted]}}
catch
exit:{duplicated_attribute, ExitAt, ExitAtL} ->
build_fault_response(-114,
"Attribute '~p' duplicated:~n~p",
[ExitAt, ExitAtL]);
exit:{attribute_not_found, ExitAt, ExitAtL} ->
build_fault_response(-116,
"Required attribute '~p' not found:~n~p",
[ExitAt, ExitAtL]);
exit:{additional_unused_args, ExitAtL} ->
build_fault_response(-120,
"The call provided additional unused "
"arguments:~n~p",
[ExitAtL]);
exit:{invalid_arg_type, Arg, Type} ->
build_fault_response(-122,
"Parameter '~p' can't be coerced to type '~p'",
[Arg, Type]);
Why ->
build_fault_response(-118,
"A problem '~p' occurred executing the "
"command ~p with arguments~n~p",
[Why, Command, AttrL])
end.
build_fault_response(Code, ParseString, ParseArgs) ->
FaultString = "Error " ++ integer_to_list(Code) ++ "\n"
++ lists:flatten(io_lib:format(ParseString, ParseArgs)),
?WARNING_MSG(FaultString, []),
{false, {response, {fault, Code, list_to_binary(FaultString)}}}.
do_command(AccessCommands, Auth, Command, AttrL, ArgsF,
ResultF) ->
ArgsFormatted = format_args(AttrL, ArgsF),
Auth2 = case AccessCommands of
V when is_list(V) ->
Auth#{extra_permissions => AccessCommands};
_ ->
Auth
end,
Result =
ejabberd_commands:execute_command2(Command, ArgsFormatted, Auth2),
ResultFormatted = format_result(Result, ResultF),
{command_result, ResultFormatted}.
%%-----------------------------
%% Format arguments
%%-----------------------------
get_attrs(Attribute_names, L) ->
[get_attr(A, L) || A <- Attribute_names].
get_attr(A, L) ->
case lists:keysearch(A, 1, L) of
{value, {A, Value}} -> Value;
false ->
%% Report the error and then force a crash
exit({attribute_not_found, A, L})
end.
get_elem_delete(A, L) ->
case proplists:get_all_values(A, L) of
[Value] -> {Value, proplists:delete(A, L)};
[_, _ | _] ->
%% Crash reporting the error
exit({duplicated_attribute, A, L});
[] ->
%% Report the error and then force a crash
exit({attribute_not_found, A, L})
end.
format_args(Args, ArgsFormat) ->
{ArgsRemaining, R} = lists:foldl(fun ({ArgName,
ArgFormat},
{Args1, Res}) ->
{ArgValue, Args2} =
get_elem_delete(ArgName,
Args1),
Formatted = format_arg(ArgValue,
ArgFormat),
{Args2, Res ++ [Formatted]}
end,
{Args, []}, ArgsFormat),
case ArgsRemaining of
[] -> R;
L when is_list(L) -> exit({additional_unused_args, L})
end.
format_arg({array, Elements},
{list, {ElementDefName, ElementDefFormat}})
when is_list(Elements) ->
lists:map(fun ({struct, [{ElementName, ElementValue}]}) when
ElementDefName == ElementName ->
format_arg(ElementValue, ElementDefFormat)
end,
Elements);
format_arg({array, [{struct, Elements}]},
{list, {ElementDefName, ElementDefFormat}})
when is_list(Elements) ->
lists:map(fun ({ElementName, ElementValue}) ->
true = ElementDefName == ElementName,
format_arg(ElementValue, ElementDefFormat)
end,
Elements);
format_arg({array, [{struct, Elements}]},
{tuple, ElementsDef})
when is_list(Elements) ->
FormattedList = format_args(Elements, ElementsDef),
list_to_tuple(FormattedList);
format_arg({array, Elements}, {list, ElementsDef})
when is_list(Elements) and is_atom(ElementsDef) ->
[format_arg(Element, ElementsDef)
|| Element <- Elements];
format_arg(Arg, integer) when is_integer(Arg) -> Arg;
format_arg(Arg, binary) when is_list(Arg) -> process_unicode_codepoints(Arg);
format_arg(Arg, binary) when is_binary(Arg) -> Arg;
format_arg(Arg, string) when is_list(Arg) -> Arg;
format_arg(Arg, string) when is_binary(Arg) -> binary_to_list(Arg);
format_arg(undefined, binary) -> <<>>;
format_arg(undefined, string) -> "";
format_arg(Arg, Format) ->
?ERROR_MSG("don't know how to format Arg ~p for format ~p", [Arg, Format]),
exit({invalid_arg_type, Arg, Format}).
process_unicode_codepoints(Str) ->
iolist_to_binary(lists:map(fun(X) when X > 255 -> unicode:characters_to_binary([X]);
(Y) -> Y
end, Str)).
%% -----------------------------
%% Result
%% -----------------------------
format_result({error, Error}, _) ->
throw({error, Error});
format_result({error, _Type, _Code, Error}, _) ->
throw({error, Error});
format_result(String, string) -> lists:flatten(String);
format_result(Atom, {Name, atom}) ->
{struct,
[{Name, iolist_to_binary(atom_to_list(Atom))}]};
format_result(Int, {Name, integer}) ->
{struct, [{Name, Int}]};
format_result([A|_]=String, {Name, string}) when is_list(String) and is_integer(A) ->
{struct, [{Name, lists:flatten(String)}]};
format_result(Binary, {Name, string}) when is_binary(Binary) ->
{struct, [{Name, binary_to_list(Binary)}]};
format_result(Atom, {Name, string}) when is_atom(Atom) ->
{struct, [{Name, atom_to_list(Atom)}]};
format_result(Integer, {Name, string}) when is_integer(Integer) ->
{struct, [{Name, integer_to_list(Integer)}]};
format_result(Other, {Name, string}) ->
{struct, [{Name, io_lib:format("~p", [Other])}]};
format_result(String, {Name, binary}) when is_list(String) ->
{struct, [{Name, lists:flatten(String)}]};
format_result(Binary, {Name, binary}) when is_binary(Binary) ->
{struct, [{Name, binary_to_list(Binary)}]};
format_result(Code, {Name, rescode}) ->
{struct, [{Name, make_status(Code)}]};
format_result({Code, Text}, {Name, restuple}) ->
{struct,
[{Name, make_status(Code)},
{text, lists:flatten(Text)}]};
%% Result is a list of something: [something()]
format_result(Elements, {Name, {list, ElementsDef}}) ->
FormattedList = lists:map(fun (Element) ->
format_result(Element, ElementsDef)
end,
Elements),
{struct, [{Name, {array, FormattedList}}]};
%% Result is a tuple with several elements: {something1(), something2(), ...}
format_result(ElementsTuple,
{Name, {tuple, ElementsDef}}) ->
ElementsList = tuple_to_list(ElementsTuple),
ElementsAndDef = lists:zip(ElementsList, ElementsDef),
FormattedList = lists:map(fun ({Element, ElementDef}) ->
format_result(Element, ElementDef)
end,
ElementsAndDef),
{struct, [{Name, {array, FormattedList}}]};
format_result(404, {Name, _}) ->
{struct, [{Name, make_status(not_found)}]}.
make_status(ok) -> 0;
make_status(true) -> 0;
make_status(false) -> 1;
make_status(error) -> 1;
make_status(_) -> 1.
transform_listen_option({access_commands, ACOpts}, Opts) ->
NewACOpts = lists:map(
fun({AName, ACmds, AOpts}) ->
{AName, [{commands, ACmds}, {options, AOpts}]};
(Opt) ->
Opt
end, ACOpts),
[{access_commands, NewACOpts}|Opts];
transform_listen_option(Opt, Opts) ->
[Opt|Opts].
listen_opt_type(access_commands) ->
fun(Opts) ->
lists:map(
fun({Ac, AcOpts}) ->
Commands = case proplists:get_value(
commands, lists:flatten(AcOpts), all) of
Cmd when is_atom(Cmd) -> Cmd;
Cmds when is_list(Cmds) ->
true = lists:all(fun is_atom/1, Cmds),
Cmds
end,
{<<"ejabberd_xmlrpc compatibility shim">>,
{[?MODULE], [{access, Ac}], Commands}}
end, lists:flatten(Opts))
end;
listen_opt_type(maxsessions) ->
fun(I) when is_integer(I), I>0 -> I end;
listen_opt_type(timeout) ->
fun(I) when is_integer(I), I>0 -> I end;
listen_opt_type(inet) -> fun(B) when is_boolean(B) -> B end;
listen_opt_type(inet6) -> fun(B) when is_boolean(B) -> B end;
listen_opt_type(backlog) ->
fun(I) when is_integer(I), I>0 -> I end;
listen_opt_type(accept_interval) ->
fun(I) when is_integer(I), I>=0 -> I end;
listen_opt_type(_) ->
[access_commands, maxsessions, timeout, backlog, inet, inet6,
accept_interval].