Allow string operators to be disabled

rebar.config.script

@@ -1,6 +1,6 @@
 %% -*- mode: erlang; indent-tabs-mode: nil -*-
 
-Conf0 = CONFIG,                                 %The original config
+Conf0 = CONFIG ++ application:get_all_env(luerl),
 
 %% Do a deep set stepping down a list of keys replacing/adding last
 %% with value. Named funs would be nicer but not always available.
@@ -45,6 +45,7 @@ Version = case erlang:system_info(otp_release) of
 %% Collect the macro definitions we will add to the compiler options.
 
 %% Erlc macro definitions.
+
 HasOpt = {d,'HAS_MAPS',true},
 FullOpt = {d,'HAS_FULL_KEYS',true},
 RecOpt = {d,'NEW_REC_CORE',true},

src/luerl.hrl

@@ -67,6 +67,16 @@
 -define(IS_INTEGER(N,I), (float(I=round(N)) =:= N)).
 -define(IS_TRUE(X), (((X) =/= nil) and ((X) =/= false))).
 
+-ifdef(SANDBOX_STRINGS).
+-define(IOLIST_TO_BINARY(S),
+        case luerl_lib_string:iolist_byte_size(S) < 64 of
+            true -> {ok, iolist_to_binary(S)};
+            false -> {error, string_too_large}
+        end).
+-else.
+-define(IOLIST_TO_BINARY(S), {ok, iolist_to_binary(S)}).
+-endif.
+
 %% Different methods for storing tables in the global data #luerl{}.
 %% Access through macros to allow testing with different storage
 %% methods. This is inefficient with ETS tables where it would

src/luerl_comp.erl

@@ -590,6 +590,7 @@ tableconstructor(Fs, St0) ->
 %% var_name(Line, Name) -> #var{}.
 %% lit_name(Line, Name) -> #lit{}.
 
+name_string(Name) when is_binary(Name) -> Name;
 name_string(Name) -> atom_to_binary(Name, latin1).
 
 lit_name(L, N) -> #lit{l=L,v=name_string(N)}.

src/luerl_emul.erl

@@ -1223,18 +1223,24 @@ le_meta(Op, A1, A2, St0) ->
 	    {boolean_value(Ret),St1}
     end.
 
+-ifdef(SANDBOX_STRINGS).
+-define(CONCAT(S1, S2), ?IOLIST_TO_BINARY([S1, S2])).
+-else.
+-define(CONCAT(S1, S2), {ok, <<S1/binary,S2/binary>>}).
+-endif.
+
 concat_op(A1, A2) ->
-    case luerl_lib:tostring(A1) of
-	nil ->
-	    {meta,fun (_, St) -> concat_meta(A1, A2, St) end};
-	S1 ->
-	    case luerl_lib:tostring(A2) of
-		nil ->
-		    {meta,fun (_, St) -> concat_meta(A1, A2, St) end};
-		S2 ->
-		    {ok,<<S1/binary,S2/binary>>}
-	    end
-    end.
+  case luerl_lib:tostring(A1) of
+    nil ->
+      {meta,fun (_, St) -> concat_meta(A1, A2, St) end};
+    S1 ->
+      case luerl_lib:tostring(A2) of
+        nil ->
+          {meta,fun (_, St) -> concat_meta(A1, A2, St) end};
+        S2 ->
+              ?CONCAT(S1, S2)
+      end
+  end.
 
 concat_meta(A1, A2, St0) ->
     case getmetamethod(A1, A2, <<"__concat">>, St0) of

src/luerl_lib_basic.erl

@@ -301,9 +301,16 @@ tostring(N) when is_number(N) ->
 		integer_to_list(round(N));
 	   true -> io_lib:write(N)
 	end,
-    iolist_to_binary(S);
+    case ?IOLIST_TO_BINARY(S) of
+      {ok, S} -> S;
+      {error, E} -> error({E, N})
+    end;
 tostring(S) when is_binary(S) -> S;
-tostring(#tref{i=I}) -> iolist_to_binary(["table: ",io_lib:write(I)]);
+tostring(#tref{i=I}) ->
+  case ?IOLIST_TO_BINARY(["table: ",io_lib:write(I)]) of
+    {ok, S} -> S;
+    {error, E} -> error({E, I})
+  end;
 tostring(#lua_func{}) -> <<"function:">>;	%Functions defined in Lua
 tostring(#erl_func{}) -> <<"function:">>;	%Internal functions
 tostring(#thread{}) -> <<"thread">>;

src/luerl_lib_string.erl

@@ -23,6 +23,9 @@
 %% The basic entry point to set up the function table.
 -export([install/1]).
 
+%% Utility
+-export([iolist_byte_size/1]).
+
 %% Export some test functions.
 -export([test_gsub/3,test_match_pat/3,test_pat/1,
 	 test_byte/3,test_do_find/4,test_sub/2,test_sub/3]).
@@ -302,6 +305,10 @@ lower(As, St) ->
 	_ -> badarg_error(lower, As, St)	%nil or []
     end.
 
+iolist_byte_size(S) when is_list(S) -> lists:sum(lists:map(fun iolist_byte_size/1, S));
+iolist_byte_size(S) when is_integer(S) -> 1;
+iolist_byte_size(S) when is_binary(S) -> byte_size(S).
+
 %% match(String, Pattern [, Init]) -> [Match].
 
 match(As, St0) ->

src/luerl_scan.xrl

@@ -116,20 +116,24 @@ Rules.
 
 Erlang code.
 
+-include("luerl.hrl").
+
 -export([is_keyword/1]).
 
 %% name_token(Chars, Line) ->
 %%     {token,{'NAME',Line,Symbol}} | {Name,Line} | {error,E}.
 %% Build a name from list of legal characters, else error.
 
 name_token(Cs, L) ->
-    case catch {ok,list_to_atom(Cs)} of
-	{ok,Name} ->
-	    case is_keyword(Name) of
-		true -> {token,{Name,L}};
-		false -> {token,{'NAME',L,Name}}
-	    end;
-	_ -> {error,"illegal name"}
+    case is_keyword(Cs) of
+        true -> {token, {list_to_atom(Cs), L}};
+        false ->
+            case ?IOLIST_TO_BINARY(Cs) of
+                {ok, B} ->
+                    {token, {'NAME', L, B}};
+                {error, string_too_large} ->
+                    {error, "identifier too long"}
+            end
     end.
 
 %% base_token(Chars, Base, Line) -> Integer.
@@ -163,8 +167,13 @@ string_token(Cs0, Len, L) ->
     Cs = string:substr(Cs0, 2, Len - 2),	%Strip quotes
     case catch {ok,chars(Cs)} of
 	{ok,S} ->
-	    {token,{'STRING',L,list_to_binary(S)}};
-	error -> {error,"illegal string"}
+            case ?IOLIST_TO_BINARY(S) of
+                {ok, B} ->
+                    {token,{'STRING',L, B}};
+                {error, string_too_large} ->
+                    {error, "string too large"}
+            end;
+  error -> {error,"illegal string"}
     end.
 
 chars([$\\,C1|Cs0]) when C1 >= $0, C1 =< $9 ->	%1-3 decimal digits
@@ -223,26 +232,26 @@ long_bracket(Line, Cs) ->
 %% is_keyword(Name) -> boolean().
 %% Test if the name is a keyword.
 
-is_keyword('and') -> true;
-is_keyword('break') -> true;
-is_keyword('do') -> true;
-is_keyword('else') -> true;
-is_keyword('elseif') -> true;
-is_keyword('end') -> true;
-is_keyword('false') -> true;
-is_keyword('for') -> true;
-is_keyword('function') -> true;
-is_keyword('goto') -> true;
-is_keyword('if') -> true;
-is_keyword('in') -> true;
-is_keyword('local') -> true;
-is_keyword('nil') -> true;
-is_keyword('not') -> true;
-is_keyword('or') -> true;
-is_keyword('repeat') -> true;
-is_keyword('return') -> true;
-is_keyword('then') -> true;
-is_keyword('true') -> true;
-is_keyword('until') -> true;
-is_keyword('while') -> true;
+is_keyword("and") -> true;
+is_keyword("break") -> true;
+is_keyword("do") -> true;
+is_keyword("else") -> true;
+is_keyword("elseif") -> true;
+is_keyword("end") -> true;
+is_keyword("false") -> true;
+is_keyword("for") -> true;
+is_keyword("function") -> true;
+is_keyword("goto") -> true;
+is_keyword("if") -> true;
+is_keyword("in") -> true;
+is_keyword("local") -> true;
+is_keyword("nil") -> true;
+is_keyword("not") -> true;
+is_keyword("or") -> true;
+is_keyword("repeat") -> true;
+is_keyword("return") -> true;
+is_keyword("then") -> true;
+is_keyword("true") -> true;
+is_keyword("until") -> true;
+is_keyword("while") -> true;
 is_keyword(_) -> false.