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shell.erl
1492 lines (1345 loc) · 47.3 KB
/
shell.erl
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%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 1996-2015. 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} ->
case expand_hist(Es0, 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)
of
{ok,Toks,_EndPos} ->
erl_parse: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 = lib: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 = erlang:get_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 -> 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) ->
case used_records(E) of
{name,Name,E1} ->
U = used_records(ets:lookup(RT, Name), [Name | U0], RT),
used_records(E1, U, RT);
{expr,[E1 | Es]} ->
used_records(Es, used_records(E1, U0, RT), RT);
_ ->
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(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 _:_ -> erlang:raise(exit, {restricted_shell_bad_return,V},
[{M,F,3} | erlang:get_stacktrace()])
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),
Forms = RecordDefs ++ [{function,L,foo,0,[{clause,L,[],[],[E]}]}],
[{function,L,foo,0,[{clause,L,[],[],[NE]}]}] =
erl_expand_records:module(Forms, [strict_record_tests]),
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,_,RecName},RecDef0], Bs, _Shell, RT, _Lf, _Ef) ->
RecDef = expand_value(RecDef0),
RDs = lists:flatten(erl_pp:expr(RecDef)),
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) ->