%% %% %CopyrightBegin% %% %% Copyright Ericsson AB 1996-2018. 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. %% You may obtain a copy of the License at %% %% http://www.apache.org/licenses/LICENSE-2.0 %% %% Unless required by applicable law or agreed to in writing, software %% distributed under the License is distributed on an "AS IS" BASIS, %% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. %% See the License for the specific language governing permissions and %% limitations under the License. %% %% %CopyrightEnd% %% -module(shell). -export([start/0, start/1, start/2, server/1, server/2, history/1, results/1]). -export([whereis_evaluator/0, whereis_evaluator/1]). -export([start_restricted/1, stop_restricted/0]). -export([local_allowed/3, non_local_allowed/3]). -export([catch_exception/1, prompt_func/1, strings/1]). -define(LINEMAX, 30). -define(CHAR_MAX, 60). -define(DEF_HISTORY, 20). -define(DEF_RESULTS, 20). -define(DEF_CATCH_EXCEPTION, false). -define(DEF_PROMPT_FUNC, default). -define(DEF_STRINGS, true). -define(RECORDS, shell_records). -define(MAXSIZE_HEAPBINARY, 64). %% When used as the fallback restricted shell callback module... local_allowed(q,[],State) -> {true,State}; local_allowed(_,_,State) -> {false,State}. non_local_allowed({init,stop},[],State) -> {true,State}; non_local_allowed(_,_,State) -> {false,State}. -spec start() -> pid(). start() -> start(false, false). start(init) -> start(false, true); start(NoCtrlG) -> start(NoCtrlG, false). start(NoCtrlG, StartSync) -> _ = code:ensure_loaded(user_default), spawn(fun() -> server(NoCtrlG, StartSync) end). %% Find the pid of the current evaluator process. -spec whereis_evaluator() -> 'undefined' | pid(). whereis_evaluator() -> %% locate top group leader, always registered as user %% can be implemented by group (normally) or user %% (if oldshell or noshell) case whereis(user) of undefined -> undefined; User -> %% get user_drv pid from group, or shell pid from user case group:interfaces(User) of [] -> % old- or noshell case user:interfaces(User) of [] -> undefined; [{shell,Shell}] -> whereis_evaluator(Shell) end; [{user_drv,UserDrv}] -> %% get current group pid from user_drv case user_drv:interfaces(UserDrv) of [] -> undefined; [{current_group,Group}] -> %% get shell pid from group GrIfs = group:interfaces(Group), case lists:keyfind(shell, 1, GrIfs) of {shell, Shell} -> whereis_evaluator(Shell); false -> undefined end end end end. -spec whereis_evaluator(pid()) -> 'undefined' | pid(). whereis_evaluator(Shell) -> case process_info(Shell, dictionary) of {dictionary,Dict} -> case lists:keyfind(evaluator, 1, Dict) of {_, Eval} when is_pid(Eval) -> Eval; _ -> undefined end; _ -> undefined end. %% Call this function to start a user restricted shell %% from a normal shell session. -spec start_restricted(Module) -> {'error', Reason} when Module :: module(), Reason :: code:load_error_rsn(). start_restricted(RShMod) when is_atom(RShMod) -> case code:ensure_loaded(RShMod) of {module,RShMod} -> application:set_env(stdlib, restricted_shell, RShMod), exit(restricted_shell_started); {error,What} = Error -> error_logger:error_report( lists:flatten( io_lib:fwrite( "Restricted shell module ~w not found: ~tp\n", [RShMod,What]))), Error end. -spec stop_restricted() -> no_return(). stop_restricted() -> application:unset_env(stdlib, restricted_shell), exit(restricted_shell_stopped). -spec server(boolean(), boolean()) -> 'terminated'. server(NoCtrlG, StartSync) -> put(no_control_g, NoCtrlG), server(StartSync). %%% The shell should not start until the system is up and running. %%% We subscribe with init to get a notification of when. %%% In older releases we didn't syncronize the shell with init, but let it %%% start in parallell with other system processes. This was bad since %%% accessing the shell too early could interfere with the boot procedure. %%% Still, by means of a flag, we make it possible to start the shell the %%% old way (for backwards compatibility reasons). This should however not %%% be used unless for very special reasons necessary. -spec server(boolean()) -> 'terminated'. server(StartSync) -> case init:get_argument(async_shell_start) of {ok,_} -> ok; % no sync with init _ when not StartSync -> ok; _ -> case init:notify_when_started(self()) of started -> ok; _ -> init:wait_until_started() end end, %% Our spawner has fixed the process groups. Bs = erl_eval:new_bindings(), %% Use an Ets table for record definitions. It takes too long to %% send a huge term to and from the evaluator. Ets makes it %% possible to have thousands of record definitions. RT = ets:new(?RECORDS, [public,ordered_set]), _ = initiate_records(Bs, RT), process_flag(trap_exit, true), %% Check if we're in user restricted mode. RShErr = case application:get_env(stdlib, restricted_shell) of {ok,RShMod} when is_atom(RShMod) -> io:fwrite(<<"Restricted ">>, []), case code:ensure_loaded(RShMod) of {module,RShMod} -> undefined; {error,What} -> {RShMod,What} end; {ok, Term} -> {Term,not_an_atom}; undefined -> undefined end, case get(no_control_g) of true -> io:fwrite(<<"Eshell V~s\n">>, [erlang:system_info(version)]); _undefined_or_false -> io:fwrite(<<"Eshell V~s (abort with ^G)\n">>, [erlang:system_info(version)]) end, erase(no_control_g), case RShErr of undefined -> ok; {RShMod2,What2} -> io:fwrite( ("Warning! Restricted shell module ~w not found: ~tp.\n" "Only the commands q() and init:stop() will be allowed!\n"), [RShMod2,What2]), application:set_env(stdlib, restricted_shell, ?MODULE) end, {History,Results} = check_and_get_history_and_results(), server_loop(0, start_eval(Bs, RT, []), Bs, RT, [], History, Results). server_loop(N0, Eval_0, Bs00, RT, Ds00, History0, Results0) -> N = N0 + 1, {Eval_1,Bs0,Ds0,Prompt} = prompt(N, Eval_0, Bs00, RT, Ds00), {Res,Eval0} = get_command(Prompt, Eval_1, Bs0, RT, Ds0), case Res of {ok,Es0,XBs} -> Es1 = erl_eval:subst_values_for_vars(Es0, XBs), case expand_hist(Es1, N) of {ok,Es} -> {V,Eval,Bs,Ds} = shell_cmd(Es, Eval0, Bs0, RT, Ds0, cmd), {History,Results} = check_and_get_history_and_results(), add_cmd(N, Es, V), HB1 = del_cmd(command, N - History, N - History0, false), HB = del_cmd(result, N - Results, N - Results0, HB1), %% The following test makes sure that large binaries %% (outside of the heap) are garbage collected as soon %% as possible. if HB -> garb(self()); true -> ok end, server_loop(N, Eval, Bs, RT, Ds, History, Results); {error,E} -> fwrite_severity(benign, <<"~ts">>, [E]), server_loop(N0, Eval0, Bs0, RT, Ds0, History0, Results0) end; {error,{Line,Mod,What}} -> fwrite_severity(benign, <<"~w: ~ts">>, [Line, Mod:format_error(What)]), server_loop(N0, Eval0, Bs0, RT, Ds0, History0, Results0); {error,terminated} -> %Io process terminated exit(Eval0, kill), terminated; {error,interrupted} -> %Io process interrupted us exit(Eval0, kill), {_,Eval,_,_} = shell_rep(Eval0, Bs0, RT, Ds0), server_loop(N0, Eval, Bs0, RT, Ds0, History0, Results0); {error,tokens} -> %Most probably character > 255 fwrite_severity(benign, <<"~w: Invalid tokens.">>, [N]), server_loop(N0, Eval0, Bs0, RT, Ds0, History0, Results0); eof -> fwrite_severity(fatal, <<"Terminating erlang (~w)">>, [node()]), halt() end. get_command(Prompt, Eval, Bs, RT, Ds) -> Parse = fun() -> exit( case io:scan_erl_exprs(group_leader(), Prompt, 1, [text]) of {ok,Toks,_EndPos} -> erl_eval:extended_parse_exprs(Toks); {eof,_EndPos} -> eof; {error,ErrorInfo,_EndPos} -> %% Skip the rest of the line: Opts = io:getopts(), TmpOpts = lists:keyreplace(echo, 1, Opts, {echo, false}), _ = io:setopts(TmpOpts), _ = io:get_line(''), _ = io:setopts(Opts), {error,ErrorInfo}; Else -> Else end ) end, Pid = spawn_link(Parse), get_command1(Pid, Eval, Bs, RT, Ds). get_command1(Pid, Eval, Bs, RT, Ds) -> receive {'EXIT', Pid, Res} -> {Res, Eval}; {'EXIT', Eval, {Reason,Stacktrace}} -> report_exception(error, {Reason,Stacktrace}, RT), get_command1(Pid, start_eval(Bs, RT, Ds), Bs, RT, Ds); {'EXIT', Eval, Reason} -> report_exception(error, {Reason,[]}, RT), get_command1(Pid, start_eval(Bs, RT, Ds), Bs, RT, Ds) end. prompt(N, Eval0, Bs0, RT, Ds0) -> case get_prompt_func() of {M,F} -> L = [{history,N}], A = erl_anno:new(1), C = {call,A,{remote,A,{atom,A,M},{atom,A,F}},[{value,A,L}]}, {V,Eval,Bs,Ds} = shell_cmd([C], Eval0, Bs0, RT, Ds0, pmt), {Eval,Bs,Ds,case V of {pmt,Val} -> Val; _ -> bad_prompt_func({M,F}), default_prompt(N) end}; default -> {Eval0,Bs0,Ds0,default_prompt(N)} end. get_prompt_func() -> case application:get_env(stdlib, shell_prompt_func) of {ok,{M,F}=PromptFunc} when is_atom(M), is_atom(F) -> PromptFunc; {ok,default=Default} -> Default; {ok,Term} -> bad_prompt_func(Term), default; undefined -> default end. bad_prompt_func(M) -> fwrite_severity(benign, "Bad prompt function: ~tp", [M]). default_prompt(N) -> %% Don't bother flattening the list irrespective of what the %% I/O-protocol states. case is_alive() of true -> io_lib:format(<<"(~s)~w> ">>, [node(), N]); false -> io_lib:format(<<"~w> ">>, [N]) end. %% expand_hist(Expressions, CommandNumber) %% Preprocess the expression list replacing all history list commands %% with their expansions. expand_hist(Es, C) -> catch {ok,expand_exprs(Es, C)}. expand_exprs([E|Es], C) -> [expand_expr(E, C)|expand_exprs(Es, C)]; expand_exprs([], _C) -> []. expand_expr({cons,L,H,T}, C) -> {cons,L,expand_expr(H, C),expand_expr(T, C)}; expand_expr({lc,L,E,Qs}, C) -> {lc,L,expand_expr(E, C),expand_quals(Qs, C)}; expand_expr({bc,L,E,Qs}, C) -> {bc,L,expand_expr(E, C),expand_quals(Qs, C)}; expand_expr({tuple,L,Elts}, C) -> {tuple,L,expand_exprs(Elts, C)}; expand_expr({map,L,Es}, C) -> {map,L,expand_exprs(Es, C)}; expand_expr({map,L,Arg,Es}, C) -> {map,L,expand_expr(Arg, C),expand_exprs(Es, C)}; expand_expr({map_field_assoc,L,K,V}, C) -> {map_field_assoc,L,expand_expr(K, C),expand_expr(V, C)}; expand_expr({map_field_exact,L,K,V}, C) -> {map_field_exact,L,expand_expr(K, C),expand_expr(V, C)}; expand_expr({record_index,L,Name,F}, C) -> {record_index,L,Name,expand_expr(F, C)}; expand_expr({record,L,Name,Is}, C) -> {record,L,Name,expand_fields(Is, C)}; expand_expr({record_field,L,R,Name,F}, C) -> {record_field,L,expand_expr(R, C),Name,expand_expr(F, C)}; expand_expr({record,L,R,Name,Ups}, C) -> {record,L,expand_expr(R, C),Name,expand_fields(Ups, C)}; expand_expr({record_field,L,R,F}, C) -> %This is really illegal! {record_field,L,expand_expr(R, C),expand_expr(F, C)}; expand_expr({block,L,Es}, C) -> {block,L,expand_exprs(Es, C)}; expand_expr({'if',L,Cs}, C) -> {'if',L,expand_cs(Cs, C)}; expand_expr({'case',L,E,Cs}, C) -> {'case',L,expand_expr(E, C),expand_cs(Cs, C)}; expand_expr({'try',L,Es,Scs,Ccs,As}, C) -> {'try',L,expand_exprs(Es, C),expand_cs(Scs, C), expand_cs(Ccs, C),expand_exprs(As, C)}; expand_expr({'receive',L,Cs}, C) -> {'receive',L,expand_cs(Cs, C)}; expand_expr({'receive',L,Cs,To,ToEs}, C) -> {'receive',L,expand_cs(Cs, C), expand_expr(To, C), expand_exprs(ToEs, C)}; expand_expr({call,L,{atom,_,e},[N]}, C) -> case get_cmd(N, C) of {undefined,_,_} -> no_command(N); {[Ce],_V,_CommandN} -> Ce; {Ces,_V,_CommandN} when is_list(Ces) -> {block,L,Ces} end; expand_expr({call,_L,{atom,_,v},[N]}, C) -> case get_cmd(N, C) of {_,undefined,_} -> no_command(N); {Ces,V,CommandN} when is_list(Ces) -> {value,erl_anno:new(CommandN),V} end; expand_expr({call,L,F,Args}, C) -> {call,L,expand_expr(F, C),expand_exprs(Args, C)}; expand_expr({'catch',L,E}, C) -> {'catch',L,expand_expr(E, C)}; expand_expr({match,L,Lhs,Rhs}, C) -> {match,L,Lhs,expand_expr(Rhs, C)}; expand_expr({op,L,Op,Arg}, C) -> {op,L,Op,expand_expr(Arg, C)}; expand_expr({op,L,Op,Larg,Rarg}, C) -> {op,L,Op,expand_expr(Larg, C),expand_expr(Rarg, C)}; expand_expr({remote,L,M,F}, C) -> {remote,L,expand_expr(M, C),expand_expr(F, C)}; expand_expr({'fun',L,{clauses,Cs}}, C) -> {'fun',L,{clauses,expand_exprs(Cs, C)}}; expand_expr({named_fun,L,Name,Cs}, C) -> {named_fun,L,Name,expand_exprs(Cs, C)}; expand_expr({clause,L,H,G,B}, C) -> %% Could expand H and G, but then erl_eval has to be changed as well. {clause,L,H, G, expand_exprs(B, C)}; expand_expr({bin,L,Fs}, C) -> {bin,L,expand_bin_elements(Fs, C)}; expand_expr(E, _C) -> % Constants. E. expand_cs([{clause,L,P,G,B}|Cs], C) -> [{clause,L,P,G,expand_exprs(B, C)}|expand_cs(Cs, C)]; expand_cs([], _C) -> []. expand_fields([{record_field,L,F,V}|Fs], C) -> [{record_field,L,expand_expr(F, C),expand_expr(V, C)}| expand_fields(Fs, C)]; expand_fields([], _C) -> []. expand_quals([{generate,L,P,E}|Qs], C) -> [{generate,L,P,expand_expr(E, C)}|expand_quals(Qs, C)]; expand_quals([{b_generate,L,P,E}|Qs], C) -> [{b_generate,L,P,expand_expr(E, C)}|expand_quals(Qs, C)]; expand_quals([E|Qs], C) -> [expand_expr(E, C)|expand_quals(Qs, C)]; expand_quals([], _C) -> []. expand_bin_elements([], _C) -> []; expand_bin_elements([{bin_element,L,E,Sz,Ts}|Fs], C) -> [{bin_element,L,expand_expr(E, C),Sz,Ts}|expand_bin_elements(Fs, C)]. no_command(N) -> throw({error, io_lib:fwrite(<<"~ts: command not found">>, [erl_pp:expr(N, enc())])}). %% add_cmd(Number, Expressions, Value) %% get_cmd(Number, CurrentCommand) %% del_cmd(Number, NewN, OldN, HasBin0) -> bool() add_cmd(N, Es, V) -> put({command,N}, Es), put({result,N}, V). getc(N) -> {get({command,N}), get({result,N}), N}. get_cmd(Num, C) -> case catch erl_eval:expr(Num, erl_eval:new_bindings()) of {value,N,_} when N < 0 -> getc(C+N); {value,N,_} -> getc(N); _Other -> {undefined,undefined,undefined} end. del_cmd(_Type, N, N0, HasBin) when N < N0 -> HasBin; del_cmd(Type, N, N0, HasBin0) -> T = erase({Type,N}), HasBin = HasBin0 orelse has_binary(T), del_cmd(Type, N-1, N0, HasBin). has_binary(T) -> try has_bin(T), false catch true=Thrown -> Thrown end. has_bin(T) when is_tuple(T) -> has_bin(T, tuple_size(T)); has_bin([E | Es]) -> has_bin(E), has_bin(Es); has_bin(B) when byte_size(B) > ?MAXSIZE_HEAPBINARY -> throw(true); has_bin(T) -> T. has_bin(T, 0) -> T; has_bin(T, I) -> has_bin(element(I, T)), has_bin(T, I - 1). %% shell_cmd(Sequence, Evaluator, Bindings, RecordTable, Dictionary, What) %% shell_rep(Evaluator, Bindings, RecordTable, Dictionary) -> %% {Value,Evaluator,Bindings,Dictionary} %% Send a command to the evaluator and wait for the reply. Start a new %% evaluator if necessary. %% What = pmt | cmd. When evaluating a prompt ('pmt') the evaluated value %% must not be displayed, and it has to be returned. shell_cmd(Es, Eval, Bs, RT, Ds, W) -> Eval ! {shell_cmd,self(),{eval,Es}, W}, shell_rep(Eval, Bs, RT, Ds). shell_rep(Ev, Bs0, RT, Ds0) -> receive {shell_rep,Ev,{value,V,Bs,Ds}} -> {V,Ev,Bs,Ds}; {shell_rep,Ev,{command_error,{Line,M,Error}}} -> fwrite_severity(benign, <<"~w: ~ts">>, [Line, M:format_error(Error)]), {{'EXIT',Error},Ev,Bs0,Ds0}; {shell_req,Ev,get_cmd} -> Ev ! {shell_rep,self(),get()}, shell_rep(Ev, Bs0, RT, Ds0); {shell_req,Ev,exit} -> Ev ! {shell_rep,self(),exit}, exit(normal); {shell_req,Ev,{update_dict,Ds}} -> % Update dictionary Ev ! {shell_rep,self(),ok}, shell_rep(Ev, Bs0, RT, Ds); {ev_exit,{Ev,Class,Reason0}} -> % It has exited unnaturally receive {'EXIT',Ev,normal} -> ok end, report_exception(Class, Reason0, RT), Reason = nocatch(Class, Reason0), {{'EXIT',Reason},start_eval(Bs0, RT, Ds0), Bs0, Ds0}; {ev_caught,{Ev,Class,Reason0}} -> % catch_exception is in effect report_exception(Class, benign, Reason0, RT), Reason = nocatch(Class, Reason0), {{'EXIT',Reason},Ev,Bs0,Ds0}; {'EXIT',_Id,interrupt} -> % Someone interrupted us exit(Ev, kill), shell_rep(Ev, Bs0, RT, Ds0); {'EXIT',Ev,{Reason,Stacktrace}} -> report_exception(exit, {Reason,Stacktrace}, RT), {{'EXIT',Reason},start_eval(Bs0, RT, Ds0), Bs0, Ds0}; {'EXIT',Ev,Reason} -> report_exception(exit, {Reason,[]}, RT), {{'EXIT',Reason},start_eval(Bs0, RT, Ds0), Bs0, Ds0}; {'EXIT',_Id,R} -> exit(Ev, R), exit(R); _Other -> % Ignore everything else shell_rep(Ev, Bs0, RT, Ds0) end. nocatch(throw, {Term,Stack}) -> {{nocatch,Term},Stack}; nocatch(error, Reason) -> Reason; nocatch(exit, Reason) -> Reason. report_exception(Class, Reason, RT) -> report_exception(Class, serious, Reason, RT). report_exception(Class, Severity, {Reason,Stacktrace}, RT) -> Tag = severity_tag(Severity), I = iolist_size(Tag) + 1, PF = fun(Term, I1) -> pp(Term, I1, RT) end, SF = fun(M, _F, _A) -> (M =:= erl_eval) or (M =:= ?MODULE) end, Enc = encoding(), Str = erl_error:format_exception(I, Class, Reason, Stacktrace, SF, PF, Enc), io:requests([{put_chars, latin1, Tag}, {put_chars, unicode, Str}, nl]). start_eval(Bs, RT, Ds) -> Self = self(), Eval = spawn_link(fun() -> evaluator(Self, Bs, RT, Ds) end), put(evaluator, Eval), Eval. %% evaluator(Shell, Bindings, RecordTable, ProcessDictionary) %% Evaluate expressions from the shell. Use the "old" variable bindings %% and dictionary. evaluator(Shell, Bs, RT, Ds) -> init_dict(Ds), case application:get_env(stdlib, restricted_shell) of undefined -> eval_loop(Shell, Bs, RT); {ok,RShMod} -> case get(restricted_shell_state) of undefined -> put(restricted_shell_state, []); _ -> ok end, put(restricted_expr_state, []), restricted_eval_loop(Shell, Bs, RT, RShMod) end. eval_loop(Shell, Bs0, RT) -> receive {shell_cmd,Shell,{eval,Es},W} -> Ef = {value, fun(MForFun, As) -> apply_fun(MForFun, As, Shell) end}, Lf = local_func_handler(Shell, RT, Ef), Bs = eval_exprs(Es, Shell, Bs0, RT, Lf, Ef, W), eval_loop(Shell, Bs, RT) end. restricted_eval_loop(Shell, Bs0, RT, RShMod) -> receive {shell_cmd,Shell,{eval,Es}, W} -> {LFH,NLFH} = restrict_handlers(RShMod, Shell, RT), put(restricted_expr_state, []), Bs = eval_exprs(Es, Shell, Bs0, RT, {eval,LFH}, {value,NLFH}, W), restricted_eval_loop(Shell, Bs, RT, RShMod) end. eval_exprs(Es, Shell, Bs0, RT, Lf, Ef, W) -> try {R,Bs2} = exprs(Es, Bs0, RT, Lf, Ef, W), Shell ! {shell_rep,self(),R}, Bs2 catch exit:normal -> exit(normal); Class:Reason:Stacktrace -> M = {self(),Class,{Reason,Stacktrace}}, case do_catch(Class, Reason) of true -> Shell ! {ev_caught,M}, Bs0; false -> %% We don't want the ERROR REPORT generated by the %% emulator. Note: exit(kill) needs nothing special. {links,LPs} = process_info(self(), links), ER = nocatch(Class, {Reason,Stacktrace}), lists:foreach(fun(P) -> exit(P, ER) end, LPs--[Shell]), Shell ! {ev_exit,M}, exit(normal) end end. do_catch(exit, restricted_shell_stopped) -> false; do_catch(exit, restricted_shell_started) -> false; do_catch(_Class, _Reason) -> case application:get_env(stdlib, shell_catch_exception) of {ok, true} -> true; _ -> false end. exprs(Es, Bs0, RT, Lf, Ef, W) -> exprs(Es, Bs0, RT, Lf, Ef, Bs0, W). exprs([E0|Es], Bs1, RT, Lf, Ef, Bs0, W) -> UsedRecords = used_record_defs(E0, RT), RBs = record_bindings(UsedRecords, Bs1), case check_command(prep_check([E0]), RBs) of ok -> E1 = expand_records(UsedRecords, E0), {value,V0,Bs2} = expr(E1, Bs1, Lf, Ef), Bs = orddict:from_list([VV || {X,_}=VV <- erl_eval:bindings(Bs2), not is_expand_variable(X)]), if Es =:= [] -> VS = pp(V0, 1, RT), case W of cmd -> io:requests([{put_chars, unicode, VS}, nl]); pmt -> ok end, %% Don't send the result back if it will be %% discarded anyway. V = if W =:= pmt -> {W,V0}; true -> case result_will_be_saved() of true -> V0; false -> erlang:garbage_collect(), ignored end end, {{value,V,Bs,get()},Bs}; true -> exprs(Es, Bs, RT, Lf, Ef, Bs0, W) end; {error,Error} -> {{command_error,Error},Bs0} end. is_expand_variable(V) -> case catch atom_to_list(V) of "rec" ++ _Integer -> true; _ -> false end. result_will_be_saved() -> case get_history_and_results() of {_, 0} -> false; _ -> true end. used_record_defs(E, RT) -> %% Be careful to return a list where used records come before %% records that use them. The linter wants them ordered that way. UR = case used_records(E, [], RT, []) of [] -> []; L0 -> L1 = lists:zip(L0, lists:seq(1, length(L0))), L2 = lists:keysort(2, lists:ukeysort(1, L1)), [R || {R, _} <- L2] end, record_defs(RT, UR). used_records(E, U0, RT, Skip) -> case used_records(E) of {name,Name,E1} -> U = case lists:member(Name, Skip) of true -> U0; false -> R = ets:lookup(RT, Name), used_records(R, [Name | U0], RT, [Name | Skip]) end, used_records(E1, U, RT, Skip); {expr,[E1 | Es]} -> used_records(Es, used_records(E1, U0, RT, Skip), RT, Skip); _ -> U0 end. used_records({record_index,_,Name,F}) -> {name, Name, F}; used_records({record,_,Name,Is}) -> {name, Name, Is}; used_records({record_field,_,R,Name,F}) -> {name, Name, [R | F]}; used_records({record,_,R,Name,Ups}) -> {name, Name, [R | Ups]}; used_records({record_field,_,R,F}) -> % illegal {expr, [R | F]}; used_records({call,_,{atom,_,record},[A,{atom,_,Name}]}) -> {name, Name, A}; used_records({call,_,{atom,_,is_record},[A,{atom,_,Name}]}) -> {name, Name, A}; used_records({call,_,{remote,_,{atom,_,erlang},{atom,_,is_record}}, [A,{atom,_,Name}]}) -> {name, Name, A}; used_records({call,_,{atom,_,record_info},[A,{atom,_,Name}]}) -> {name, Name, A}; used_records({call,Line,{tuple,_,[M,F]},As}) -> used_records({call,Line,{remote,Line,M,F},As}); used_records({type,_,record,[{atom,_,Name}|Fs]}) -> {name, Name, Fs}; used_records(T) when is_tuple(T) -> {expr, tuple_to_list(T)}; used_records(E) -> {expr, E}. fwrite_severity(Severity, S, As) -> io:fwrite(<<"~ts\n">>, [format_severity(Severity, S, As)]). format_severity(Severity, S, As) -> add_severity(Severity, io_lib:fwrite(S, As)). add_severity(Severity, S) -> [severity_tag(Severity), S]. severity_tag(fatal) -> <<"*** ">>; severity_tag(serious) -> <<"** ">>; severity_tag(benign) -> <<"* ">>. restrict_handlers(RShMod, Shell, RT) -> { fun(F,As,Binds) -> local_allowed(F, As, RShMod, Binds, Shell, RT) end, fun(MF,As) -> non_local_allowed(MF, As, RShMod, Shell) end }. -define(BAD_RETURN(M, F, V), try erlang:error(reason) catch _:_:S -> erlang:raise(exit, {restricted_shell_bad_return,V}, [{M,F,3} | S]) end). local_allowed(F, As, RShMod, Bs, Shell, RT) when is_atom(F) -> {LFH,NLFH} = restrict_handlers(RShMod, Shell, RT), case not_restricted(F, As) of % Not restricted is the same as builtin. % variable and record manipulations local % to the shell process. Those are never % restricted. true -> local_func(F, As, Bs, Shell, RT, {eval,LFH}, {value,NLFH}); false -> {AsEv,Bs1} = expr_list(As, Bs, {eval,LFH}, {value,NLFH}), case RShMod:local_allowed(F, AsEv, {get(restricted_shell_state), get(restricted_expr_state)}) of {Result,{RShShSt,RShExprSt}} -> put(restricted_shell_state, RShShSt), put(restricted_expr_state, RShExprSt), if not Result -> shell_req(Shell, {update_dict,get()}), exit({restricted_shell_disallowed,{F,AsEv}}); true -> % This is never a builtin, % those are handled above. non_builtin_local_func(F,AsEv,Bs1) end; Unexpected -> % The user supplied non conforming module ?BAD_RETURN(RShMod, local_allowed, Unexpected) end end. non_local_allowed(MForFun, As, RShMod, Shell) -> case RShMod:non_local_allowed(MForFun, As, {get(restricted_shell_state), get(restricted_expr_state)}) of {Result,{RShShSt,RShExprSt}} -> put(restricted_shell_state, RShShSt), put(restricted_expr_state, RShExprSt), case Result of false -> shell_req(Shell, {update_dict,get()}), exit({restricted_shell_disallowed,{MForFun,As}}); {redirect, NewMForFun, NewAs} -> apply_fun(NewMForFun, NewAs, Shell); _ -> apply_fun(MForFun, As, Shell) end; Unexpected -> % The user supplied non conforming module ?BAD_RETURN(RShMod, non_local_allowed, Unexpected) end. %% The commands implemented in shell should not be checked if allowed %% This *has* to correspond to the function local_func/7! %% (especially true for f/1, the argument must not be evaluated). not_restricted(f, []) -> true; not_restricted(f, [_]) -> true; not_restricted(h, []) -> true; not_restricted(b, []) -> true; not_restricted(history, [_]) -> true; not_restricted(results, [_]) -> true; not_restricted(catch_exception, [_]) -> true; not_restricted(exit, []) -> true; not_restricted(rd, [_,_]) -> true; not_restricted(rf, []) -> true; not_restricted(rf, [_]) -> true; not_restricted(rl, []) -> true; not_restricted(rl, [_]) -> true; not_restricted(rp, [_]) -> true; not_restricted(rr, [_]) -> true; not_restricted(rr, [_,_]) -> true; not_restricted(rr, [_,_,_]) -> true; not_restricted(_, _) -> false. %% When erlang:garbage_collect() is called from the shell, %% the shell process process that spawned the evaluating %% process is garbage collected as well. %% To garbage collect the evaluating process only the command %% garbage_collect(self()). can be used. apply_fun({erlang,garbage_collect}, [], Shell) -> garb(Shell); apply_fun({M,F}, As, _Shell) -> apply(M, F, As); apply_fun(MForFun, As, _Shell) -> apply(MForFun, As). prep_check({call,Line,{atom,_,f},[{var,_,_Name}]}) -> %% Do not emit a warning for f(V) when V is unbound. {atom,Line,ok}; prep_check({value,_CommandN,_Val}) -> %% erl_lint cannot handle the history expansion {value,_,_}. {atom,a0(),ok}; prep_check(T) when is_tuple(T) -> list_to_tuple(prep_check(tuple_to_list(T))); prep_check([E | Es]) -> [prep_check(E) | prep_check(Es)]; prep_check(E) -> E. expand_records([], E0) -> E0; expand_records(UsedRecords, E0) -> RecordDefs = [Def || {_Name,Def} <- UsedRecords], L = erl_anno:new(1), E = prep_rec(E0), Forms0 = RecordDefs ++ [{function,L,foo,0,[{clause,L,[],[],[E]}]}], Forms = erl_expand_records:module(Forms0, [strict_record_tests]), {function,L,foo,0,[{clause,L,[],[],[NE]}]} = lists:last(Forms), prep_rec(NE). prep_rec({value,_CommandN,_V}=Value) -> %% erl_expand_records cannot handle the history expansion {value,_,_}. {atom,Value,ok}; prep_rec({atom,{value,_CommandN,_V}=Value,ok}) -> %% Undo the effect of the previous clause... Value; prep_rec(T) when is_tuple(T) -> list_to_tuple(prep_rec(tuple_to_list(T))); prep_rec([E | Es]) -> [prep_rec(E) | prep_rec(Es)]; prep_rec(E) -> E. init_dict([{K,V}|Ds]) -> put(K, V), init_dict(Ds); init_dict([]) -> true. %% local_func(Function, Args, Bindings, Shell, RecordTable, %% LocalFuncHandler, ExternalFuncHandler) -> {value,Val,Bs} %% Evaluate local functions, including shell commands. %% %% Note that the predicate not_restricted/2 has to correspond to what's %% handled internally - it should return 'true' for all local functions %% handled in this module (i.e. those that are not eventually handled by %% non_builtin_local_func/3 (user_default/shell_default). local_func(h, [], Bs, Shell, RT, _Lf, _Ef) -> Cs = shell_req(Shell, get_cmd), Cs1 = lists:filter(fun({{command, _},_}) -> true; ({{result, _},_}) -> true; (_) -> false end, Cs), Cs2 = lists:map(fun({{T, N}, V}) -> {{N, T}, V} end, Cs1), Cs3 = lists:keysort(1, Cs2), {value,list_commands(Cs3, RT),Bs}; local_func(b, [], Bs, _Shell, RT, _Lf, _Ef) -> {value,list_bindings(erl_eval:bindings(Bs), RT),Bs}; local_func(f, [], _Bs, _Shell, _RT, _Lf, _Ef) -> {value,ok,erl_eval:new_bindings()}; local_func(f, [{var,_,Name}], Bs, _Shell, _RT, _Lf, _Ef) -> {value,ok,erl_eval:del_binding(Name, Bs)}; local_func(f, [_Other], _Bs, _Shell, _RT, _Lf, _Ef) -> erlang:raise(error, function_clause, [{shell,f,1}]); local_func(rd, [{atom,_,RecName0},RecDef0], Bs, _Shell, RT, _Lf, _Ef) -> RecDef = expand_value(RecDef0), RDs = lists:flatten(erl_pp:expr(RecDef)), RecName = io_lib:write_atom_as_latin1(RecName0), Attr = lists:concat(["-record(", RecName, ",", RDs, ")."]), {ok, Tokens, _} = erl_scan:string(Attr), case erl_parse:parse_form(Tokens) of {ok,AttrForm} -> [RN] = add_records([AttrForm], Bs, RT), {value,RN,Bs}; {error,{_Line,M,ErrDesc}} -> ErrStr = io_lib:fwrite(<<"~ts">>, [M:format_error(ErrDesc)]), exit(lists:flatten(ErrStr)) end; local_func(rd, [_,_], _Bs, _Shell, _RT, _Lf, _Ef) -> erlang:raise(error, function_clause, [{shell,rd,2}]); local_func(rf, [], Bs, _Shell, RT, _Lf, _Ef) -> true = ets:delete_all_objects(RT), {value,initiate_records(Bs, RT),Bs}; local_func(rf, [A], Bs0, _Shell, RT, Lf, Ef) -> {[Recs],Bs} = expr_list([A], Bs0, Lf, Ef), if '_' =:= Recs -> true = ets:delete_all_objects(RT); true -> lists:foreach(fun(Name) -> true = ets:delete(RT, Name) end, listify(Recs)) end, {value,ok,Bs}; local_func(rl, [], Bs, _Shell, RT, _Lf, _Ef) -> {value,list_records(ets:tab2list(RT)),Bs}; local_func(rl, [A], Bs0, _Shell, RT, Lf, Ef) -> {[Recs],Bs} = expr_list([A], Bs0, Lf, Ef), {value,list_records(record_defs(RT, listify(Recs))),Bs}; local_func(rp, [A], Bs0, _Shell, RT, Lf, Ef) -> {[V],Bs} = expr_list([A], Bs0, Lf, Ef), Cs = pp(V, _Column=1, _Depth=-1, RT), io:requests([{put_chars, unicode, Cs}, nl]), {value,ok,Bs}; local_func(rr, [A], Bs0, _Shell, RT, Lf, Ef) -> {[File],Bs} = expr_list([A], Bs0, Lf, Ef), {value,read_and_add_records(File, '_', [], Bs, RT),Bs}; local_func(rr, [_,_]=As0, Bs0, _Shell, RT, Lf, Ef) -> {[File,Sel],Bs} = expr_list(As0, Bs0, Lf, Ef), {value,read_and_add_records(File, Sel, [], Bs, RT),Bs}; local_func(rr, [_,_,_]=As0, Bs0, _Shell, RT, Lf, Ef) -> {[File,Sel,Options],Bs} = expr_list(As0, Bs0, Lf, Ef), {value,read_and_add_records(File, Sel, Options, Bs, RT),Bs}; local_func(history, [{integer,_,N}], Bs, _Shell, _RT, _Lf, _Ef) -> {value,history(N),Bs}; local_func(history, [_Other], _Bs, _Shell, _RT, _Lf, _Ef) -> erlang:raise(error, function_clause, [{shell,history,1}]); local_func(results, [{integer,_,N}], Bs, _Shell, _RT, _Lf, _Ef) -> {value,results(N),Bs}; local_func(results, [_Other], _Bs, _Shell, _RT, _Lf, _Ef) -> erlang:raise(error, function_clause, [{shell,results,1}]); local_func(catch_exception, [{atom,_,Bool}], Bs, _Shell, _RT, _Lf, _Ef) when Bool; not Bool -> {value,catch_exception(Bool),Bs}; local_func(catch_exception, [_Other], _Bs, _Shell, _RT, _Lf, _Ef) -> erlang:raise(error, function_clause, [{shell,catch_exception,1}]); local_func(exit, [], _Bs, Shell, _RT, _Lf, _Ef) -> shell_req(Shell, exit), %This terminates us exit(normal); local_func(F, As0, Bs0, _Shell, _RT, Lf, Ef) when is_atom(F) -> {As,Bs} = expr_list(As0, Bs0, Lf, Ef), non_builtin_local_func(F,As,Bs). non_builtin_local_func(F,As,Bs) -> Arity = length(As), case erlang:function_exported(user_default, F, Arity) of true -> {eval,erlang:make_fun(user_default, F, Arity),As,Bs}; false -> shell_default(F,As,Bs) end. shell_default(F,As,Bs) -> M = shell_default, A = length(As), case code:ensure_loaded(M) of {module, _} -> case erlang:function_exported(M,F,A) of true -> {eval,erlang:make_fun(M, F, A),As,Bs}; false -> shell_undef(F,A) end; {error, _} -> shell_undef(F,A) end. shell_undef(F,A) -> erlang:error({shell_undef,F,A,[]}). local_func_handler(Shell, RT, Ef) -> H = fun(Lf) -> fun(F, As, Bs) -> local_func(F, As, Bs, Shell, RT, {eval,Lf(Lf)}, Ef) end end, {eval,H(H)}. record_print_fun(RT) -> fun(Tag, NoFields) -> case ets:lookup(RT, Tag) of [{_,{attribute,_,record,{Tag,Fields}}}] when length(Fields) =:= NoFields -> record_fields(Fields); _ -> no end end. record_fields([{record_field,_,{atom,_,Field}} | Fs]) -> [Field | record_fields(Fs)]; record_fields([{record_field,_,{atom,_,Field},_} | Fs]) -> [Field | record_fields(Fs)]; record_fields([{typed_record_field,Field,_Type} | Fs]) -> record_fields([Field | Fs]); record_fields([]) -> []. initiate_records(Bs, RT) -> RNs1 = init_rec(shell_default, Bs, RT), RNs2 = case code:is_loaded(user_default) of {file,_File} -> init_rec(user_default, Bs, RT); false -> [] end, lists:usort(RNs1 ++ RNs2). init_rec(Module, Bs, RT) -> case read_records(Module, []) of RAs when is_list(RAs) -> case catch add_records(RAs, Bs, RT) of {'EXIT',_} -> []; RNs -> RNs end; _Error -> [] end. read_and_add_records(File, Selected, Options, Bs, RT) -> case read_records(File, Selected, Options) of RAs when is_list(RAs) -> add_records(RAs, Bs, RT); Error -> Error end. read_records(File, Selected, Options) -> case read_records(File, listify(Options)) of Error when is_tuple(Error) -> Error; RAs when Selected =:= '_' -> RAs; RAs -> Sel = listify(Selected), [RA || {attribute,_,_,{Name,_}}=RA <- RAs, lists:member(Name, Sel)] end. add_records(RAs, Bs0, RT) -> Recs = [{Name,D} || {attribute,_,_,{Name,_}}=D <- RAs], Bs1 = record_bindings(Recs, Bs0), case check_command([], Bs1) of {error,{_Line,M,ErrDesc}} -> %% A source file that has not been compiled. ErrStr = io_lib:fwrite(<<"~ts">>, [M:format_error(ErrDesc)]), exit(lists:flatten(ErrStr)); ok -> true = ets:insert(RT, Recs), lists:usort([Name || {Name,_} <- Recs]) end. listify(L) when is_list(L) -> L; listify(E) -> [E]. check_command(Es, Bs) -> erl_eval:check_command(Es, Bs). expr(E, Bs, Lf, Ef) -> erl_eval:expr(E, Bs, Lf, Ef). expr_list(Es, Bs, Lf, Ef) -> erl_eval:expr_list(Es, Bs, Lf, Ef). %% Note that a sequence number is used here to make sure that if a %% record is used by another record, then the first record is parsed %% before the second record. (erl_eval:check_command() calls the %% linter which needs the records in a proper order.) record_bindings([], Bs) -> Bs; record_bindings(Recs0, Bs0) -> {Recs1, _} = lists:mapfoldl(fun ({Name,Def}, I) -> {{Name,I,Def},I+1} end, 0, Recs0), Recs2 = lists:keysort(2, lists:ukeysort(1, Recs1)), lists:foldl(fun ({Name,I,Def}, Bs) -> erl_eval:add_binding({record,I,Name}, Def, Bs) end, Bs0, Recs2). %%% Read record information from file(s) read_records(FileOrModule, Opts0) -> Opts = lists:delete(report_warnings, Opts0), case find_file(FileOrModule) of {files,[File]} -> read_file_records(File, Opts); {files,Files} -> lists:flatmap(fun(File) -> case read_file_records(File, Opts) of RAs when is_list(RAs) -> RAs; _ -> [] end end, Files); Error -> Error end. -include_lib("kernel/include/file.hrl"). find_file(Mod) when is_atom(Mod) -> case code:which(Mod) of File when is_list(File) -> {files,[File]}; preloaded -> {_M,_Bin,File} = code:get_object_code(Mod), {files,[File]}; _Else -> % non_existing, interpreted, cover_compiled {error,nofile} end; find_file(File) -> case catch filelib:wildcard(File) of {'EXIT',_} -> {error,invalid_filename}; Files -> {files,Files} end. read_file_records(File, Opts) -> case filename:extension(File) of ".beam" -> case beam_lib:chunks(File, [abstract_code,"CInf"]) of {ok,{_Mod,[{abstract_code,{Version,Forms}},{"CInf",CB}]}} -> case record_attrs(Forms) of [] when Version =:= raw_abstract_v1 -> []; [] -> %% If the version is raw_X, then this test %% is unnecessary. try_source(File, CB); Records -> Records end; {ok,{_Mod,[{abstract_code,no_abstract_code},{"CInf",CB}]}} -> try_source(File, CB); Error -> %% Could be that the "Abst" chunk is missing (pre R6). Error end; _ -> parse_file(File, Opts) end. %% This is how the debugger searches for source files. See int.erl. try_source(Beam, RawCB) -> EbinDir = filename:dirname(Beam), CB = binary_to_term(RawCB), Os = proplists:get_value(options,CB, []), Src0 = filename:rootname(Beam) ++ ".erl", Src1 = filename:join([filename:dirname(EbinDir), "src", filename:basename(Src0)]), Src2 = proplists:get_value(source, CB, []), try_sources([Src0,Src1,Src2], Os). try_sources([], _) -> {error, nofile}; try_sources([Src|Rest], Os) -> case is_file(Src) of true -> parse_file(Src, Os); false -> try_sources(Rest, Os) end. is_file(Name) -> case filelib:is_file(Name) of true -> not filelib:is_dir(Name); false -> false end. parse_file(File, Opts) -> Cwd = ".", Dir = filename:dirname(File), IncludePath = [Cwd,Dir|inc_paths(Opts)], case epp:parse_file(File, IncludePath, pre_defs(Opts)) of {ok,Forms} -> record_attrs(Forms); Error -> Error end. pre_defs([{d,M,V}|Opts]) -> [{M,V}|pre_defs(Opts)]; pre_defs([{d,M}|Opts]) -> [M|pre_defs(Opts)]; pre_defs([_|Opts]) -> pre_defs(Opts); pre_defs([]) -> []. inc_paths(Opts) -> [P || {i,P} <- Opts, is_list(P)]. record_attrs(Forms) -> [A || A = {attribute,_,record,_D} <- Forms]. %%% End of reading record information from file(s) shell_req(Shell, Req) -> Shell ! {shell_req,self(),Req}, receive {shell_rep,Shell,Rep} -> Rep end. list_commands([{{N,command},Es0}, {{N,result}, V} |Ds], RT) -> Es = prep_list_commands(Es0), VS = pp(V, 4, RT), Ns = io_lib:fwrite(<<"~w: ">>, [N]), I = iolist_size(Ns), io:requests([{put_chars, latin1, Ns}, {format,<<"~ts\n">>,[erl_pp:exprs(Es, I, enc())]}, {format,<<"-> ">>,[]}, {put_chars, unicode, VS}, nl]), list_commands(Ds, RT); list_commands([{{N,command},Es0} |Ds], RT) -> Es = prep_list_commands(Es0), Ns = io_lib:fwrite(<<"~w: ">>, [N]), I = iolist_size(Ns), io:requests([{put_chars, latin1, Ns}, {format,<<"~ts\n">>,[erl_pp:exprs(Es, I, enc())]}]), list_commands(Ds, RT); list_commands([_D|Ds], RT) -> list_commands(Ds, RT); list_commands([], _RT) -> ok. list_bindings([{Name,Val}|Bs], RT) -> case erl_eval:fun_data(Val) of {fun_data,_FBs,FCs0} -> FCs = expand_value(FCs0), % looks nicer A = a0(), F = {'fun',A,{clauses,FCs}}, M = {match,A,{var,A,Name},F}, io:fwrite(<<"~ts\n">>, [erl_pp:expr(M, enc())]); {named_fun_data,_FBs,FName,FCs0} -> FCs = expand_value(FCs0), % looks nicer A = a0(), F = {named_fun,A,FName,FCs}, M = {match,A,{var,A,Name},F}, io:fwrite(<<"~ts\n">>, [erl_pp:expr(M, enc())]); false -> Namel = io_lib:fwrite(<<"~s = ">>, [Name]), Nl = iolist_size(Namel)+1, ValS = pp(Val, Nl, RT), io:requests([{put_chars, latin1, Namel}, {put_chars, unicode, ValS}, nl]) end, list_bindings(Bs, RT); list_bindings([], _RT) -> ok. list_records(Records) -> lists:foreach(fun({_Name,Attr}) -> io:fwrite(<<"~ts">>, [erl_pp:attribute(Attr, enc())]) end, Records). record_defs(RT, Names) -> lists:flatmap(fun(Name) -> ets:lookup(RT, Name) end, Names). expand_value(E) -> substitute_v1(fun({value,CommandN,V}) -> try_abstract(V, CommandN) end, E). %% There is no abstract representation of funs. try_abstract(V, CommandN) -> try erl_parse:abstract(V) catch _:_ -> A = a0(), {call,A,{atom,A,v},[{integer,A,CommandN}]} end. %% Rather than listing possibly huge results the calls to v/1 are shown. prep_list_commands(E) -> A = a0(), substitute_v1(fun({value,Anno,_V}) -> CommandN = erl_anno:line(Anno), {call,A,{atom,A,v},[{integer,A,CommandN}]} end, E). substitute_v1(F, {value,_,_}=Value) -> F(Value); substitute_v1(F, T) when is_tuple(T) -> list_to_tuple(substitute_v1(F, tuple_to_list(T))); substitute_v1(F, [E | Es]) -> [substitute_v1(F, E) | substitute_v1(F, Es)]; substitute_v1(_F, E) -> E. a0() -> erl_anno:new(0). check_and_get_history_and_results() -> check_env(shell_history_length), check_env(shell_saved_results), get_history_and_results(). get_history_and_results() -> History = get_env(shell_history_length, ?DEF_HISTORY), Results = get_env(shell_saved_results, ?DEF_RESULTS), {History, erlang:min(Results, History)}. pp(V, I, RT) -> pp(V, I, _Depth=?LINEMAX, RT). pp(V, I, D, RT) -> Strings = case application:get_env(stdlib, shell_strings) of {ok, false} -> false; _ -> true end, io_lib_pretty:print(V, ([{column, I}, {line_length, columns()}, {depth, D}, {line_max_chars, ?CHAR_MAX}, {strings, Strings}, {record_print_fun, record_print_fun(RT)}] ++ enc())). columns() -> case io:columns() of {ok,N} -> N; _ -> 80 end. encoding() -> [{encoding, Encoding}] = enc(), Encoding. enc() -> case lists:keyfind(encoding, 1, io:getopts()) of false -> [{encoding,latin1}]; % should never happen Enc -> [Enc] end. garb(Shell) -> erlang:garbage_collect(Shell), catch erlang:garbage_collect(whereis(user)), catch erlang:garbage_collect(group_leader()), erlang:garbage_collect(). get_env(V, Def) -> case application:get_env(stdlib, V) of {ok, Val} when is_integer(Val), Val >= 0 -> Val; _ -> Def end. check_env(V) -> case application:get_env(stdlib, V) of undefined -> ok; {ok, Val} when is_integer(Val), Val >= 0 -> ok; {ok, Val} -> Txt = io_lib:fwrite ("Invalid value of STDLIB configuration parameter" "~tw: ~tp\n", [V, Val]), error_logger:info_report(lists:flatten(Txt)) end. set_env(App, Name, Val, Default) -> Prev = case application:get_env(App, Name) of undefined -> Default; {ok, Old} -> Old end, application_controller:set_env(App, Name, Val), Prev. -spec history(N) -> non_neg_integer() when N :: non_neg_integer(). history(L) when is_integer(L), L >= 0 -> set_env(stdlib, shell_history_length, L, ?DEF_HISTORY). -spec results(N) -> non_neg_integer() when N :: non_neg_integer(). results(L) when is_integer(L), L >= 0 -> set_env(stdlib, shell_saved_results, L, ?DEF_RESULTS). -spec catch_exception(Bool) -> boolean() when Bool :: boolean(). catch_exception(Bool) -> set_env(stdlib, shell_catch_exception, Bool, ?DEF_CATCH_EXCEPTION). -spec prompt_func(PromptFunc) -> PromptFunc2 when PromptFunc :: 'default' | {module(),atom()}, PromptFunc2 :: 'default' | {module(),atom()}. prompt_func(String) -> set_env(stdlib, shell_prompt_func, String, ?DEF_PROMPT_FUNC). -spec strings(Strings) -> Strings2 when Strings :: boolean(), Strings2 :: boolean(). strings(Strings) -> set_env(stdlib, shell_strings, Strings, ?DEF_STRINGS).