aboutsummaryrefslogblamecommitdiffstats
path: root/lib/stdlib/src/beam_lib.erl
blob: e9a5e6831e1b45c9473c8eca753085958a4b46a1 (plain) (tree)
1
2
3
4
5
6
7
8
9
10
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837

                   
  
                                                        
  




                                                                      
  



                                                                         
  




                       



                                                                           





















                                                                           

                                                                  


                                                           



                                                                           
                                                 
 
                                                                           












                                                                            


                                                                            







                                                           
                                                                                            



                                                          

                                                       



                                                                









                                                                   
                                       







                                                                           







                                                                       



                                   




                                                          



                                  






                                                                             









                                                                       


                                                                       




                               







                                                                                  



                                   



                                                                        



                                       



                                                                          




                             



                                                                           




                                         
                           
                                             


                                                         



                          



                                                              









                                                          



                                                                        

            
                                                             






                                                                  

                                                 



















































                                                                                       


                                                                   



                                            

                                                                 




































































                                                                        

                                                        

                    
                              

























                                                                           
                                                                              










































                                                             













                                                           

                                                                    



























































































































































































































































































































































































                                                                                 
                                                                

                       





                                                                         



















































                                                                        




                                                         

        



                                                                  









































































































































































                                                                             
%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 2000-2011. All Rights Reserved.
%%
%% The contents of this file are subject to the Erlang Public License,
%% Version 1.1, (the "License"); you may not use this file except in
%% compliance with the License. You should have received a copy of the
%% Erlang Public License along with this software. If not, it can be
%% retrieved online at http://www.erlang.org/.
%%
%% Software distributed under the License is distributed on an "AS IS"
%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
%% the License for the specific language governing rights and limitations
%% under the License.
%%
%% %CopyrightEnd%
%%
-module(beam_lib).
-behaviour(gen_server).

%% Avoid warning for local function error/1 clashing with autoimported BIF.
-compile({no_auto_import,[error/1]}).
%% Avoid warning for local function error/2 clashing with autoimported BIF.
-compile({no_auto_import,[error/2]}).
-export([info/1,
	 cmp/2,
	 cmp_dirs/2,
	 chunks/2,
	 chunks/3,
	 all_chunks/1,
	 diff_dirs/2,
	 strip/1,
	 strip_files/1,
	 strip_release/1,
	 build_module/1,
	 version/1,
	 md5/1,
	 format_error/1]).

%% The following functions implement encrypted debug info.

-export([crypto_key_fun/1, clear_crypto_key_fun/0]).
-export([init/1,handle_call/3,handle_cast/2,handle_info/2,
	 terminate/2,code_change/3]).
-export([make_crypto_key/2, get_crypto_key/1]).	%Utilities used by compiler

-export_type([attrib_entry/0, compinfo_entry/0, labeled_entry/0]).

-import(lists, [append/1, delete/2, foreach/2, keysort/2, 
		member/2, reverse/1, sort/1, splitwith/2]).

%%-------------------------------------------------------------------------

-type beam() :: module() | file:filename() | binary().

-type forms()     :: [erl_parse:abstract_form()].

-type abst_code() :: {AbstVersion :: atom(), forms()} | 'no_abstract_code'.
-type dataB()     :: binary().
-type index()     :: non_neg_integer().
-type label()     :: integer().

-type chunkid()   :: nonempty_string(). % approximation of the strings below
%% "Abst" | "Attr" | "CInf" | "ExpT" | "ImpT" | "LocT" | "Atom".
-type chunkname() :: 'abstract_code' | 'attributes' | 'compile_info'
                   | 'exports' | 'labeled_exports'
                   | 'imports' | 'indexed_imports'
                   | 'locals' | 'labeled_locals'
                   | 'atoms'.
-type chunkref()  :: chunkname() | chunkid().

-type attrib_entry()   :: {Attribute :: atom(), [AttributeValue :: term()]}.
-type compinfo_entry() :: {InfoKey :: atom(), term()}.
-type labeled_entry()  :: {Function :: atom(), arity(), label()}.

-type chunkdata() :: {chunkid(), dataB()}
                   | {'abstract_code', abst_code()}
                   | {'attributes', [attrib_entry()]}
                   | {'compile_info', [compinfo_entry()]}
                   | {'exports', [{atom(), arity()}]}
                   | {'labeled_exports', [labeled_entry()]}
                   | {'imports', [mfa()]}
                   | {'indexed_imports', [{index(), module(), Function :: atom(), arity()}]}
                   | {'locals', [{atom(), arity()}]}
                   | {'labeled_locals', [labeled_entry()]}
                   | {'atoms', [{integer(), atom()}]}.

%% Error reasons
-type info_rsn()  :: {'chunk_too_big', file:filename(),
		      chunkid(), ChunkSize :: non_neg_integer(),
                      FileSize :: non_neg_integer()}
                   | {'invalid_beam_file', file:filename(),
                      Position :: non_neg_integer()}
                   | {'invalid_chunk', file:filename(), chunkid()}
                   | {'missing_chunk', file:filename(), chunkid()}
                   | {'not_a_beam_file', file:filename()}
                   | {'file_error', file:filename(), file:posix()}.
-type chnk_rsn()  :: {'unknown_chunk', file:filename(), atom()}
                   | {'key_missing_or_invalid', file:filename(),
		      'abstract_code'}
                   | info_rsn().
-type cmp_rsn()   :: {'modules_different', module(), module()}
                   | {'chunks_different', chunkid()}
                   | 'different_chunks'
                   | info_rsn().

%%-------------------------------------------------------------------------

%%
%%  Exported functions
%%

-spec info(Beam) -> [InfoPair] | {'error', 'beam_lib', info_rsn()} when
      Beam :: beam(),
      InfoPair :: {'file', Filename :: file:filename()}
                | {'binary', Binary :: binary()}
                | {'module', Module :: module()}
                | {'chunks', [{ChunkId :: chunkid(),
                               Pos :: non_neg_integer(),
                               Size :: non_neg_integer()}]}.

info(File) ->
    read_info(beam_filename(File)).

-spec chunks(Beam, ChunkRefs) ->
                    {'ok', {module(), [chunkdata()]}} |
                    {'error', 'beam_lib', chnk_rsn()} when
      Beam :: beam(),
      ChunkRefs :: [chunkref()].

chunks(File, Chunks) ->
    read_chunk_data(File, Chunks).

-spec chunks(Beam, ChunkRefs, Options) ->
                    {'ok', {module(), [ChunkResult]}} |
                    {'error', 'beam_lib', chnk_rsn()} when
      Beam :: beam(),
      ChunkRefs :: [chunkref()],
      Options :: ['allow_missing_chunks'],
      ChunkResult :: chunkdata() | {ChunkRef :: chunkref(), 'missing_chunk'}.

chunks(File, Chunks, Options) ->
    try read_chunk_data(File, Chunks, Options)
    catch Error -> Error end.

-spec all_chunks(beam()) -> {'ok', 'beam_lib', [{chunkid(), dataB()}]}.

all_chunks(File) ->
    read_all_chunks(File).

-spec cmp(Beam1, Beam2) -> 'ok' | {'error', 'beam_lib', cmp_rsn()} when
      Beam1 :: beam(),
      Beam2 :: beam().

cmp(File1, File2) ->
    try cmp_files(File1, File2)
    catch Error -> Error end.

-spec cmp_dirs(Dir1, Dir2) ->
           {Only1, Only2, Different} | {'error', 'beam_lib', Reason} when
      Dir1 :: atom() | file:filename(),
      Dir2 :: atom() | file:filename(),
      Only1 :: [file:filename()],
      Only2 :: [file:filename()],
      Different :: [{Filename1 :: file:filename(), Filename2 :: file:filename()}],
      Reason :: {'not_a_directory', term()} | info_rsn().

cmp_dirs(Dir1, Dir2) ->
    catch compare_dirs(Dir1, Dir2).

-spec diff_dirs(Dir1, Dir2) -> 'ok' | {'error', 'beam_lib', Reason} when
      Dir1 :: atom() | file:filename(),
      Dir2 :: atom() | file:filename(),
      Reason :: {'not_a_directory', term()} | info_rsn().

diff_dirs(Dir1, Dir2) ->
    catch diff_directories(Dir1, Dir2).

-spec strip(Beam1) ->
        {'ok', {module(), Beam2}} | {'error', 'beam_lib', info_rsn()} when
      Beam1 :: beam(),
      Beam2 :: beam().

strip(FileName) ->
    try strip_file(FileName)
    catch Error -> Error end.
    
-spec strip_files(Files) ->
        {'ok', [{module(), Beam}]} | {'error', 'beam_lib', info_rsn()} when
      Files :: [beam()],
      Beam :: beam().

strip_files(Files) when is_list(Files) ->
    try strip_fils(Files)
    catch Error -> Error end.

-spec strip_release(Dir) ->
        {'ok', [{module(), file:filename()}]}
      | {'error', 'beam_lib', Reason} when
      Dir :: atom() | file:filename(),
      Reason :: {'not_a_directory', term()} | info_rsn().

strip_release(Root) ->
    catch strip_rel(Root).

-spec version(Beam) ->
                     {'ok', {module(), [Version :: term()]}} |
                     {'error', 'beam_lib', chnk_rsn()} when
      Beam :: beam().

version(File) ->
    case catch read_chunk_data(File, [attributes]) of
	{ok, {Module, [{attributes, Attrs}]}} ->
	    {vsn, Version} = lists:keyfind(vsn, 1, Attrs),
	    {ok, {Module, Version}};
	Error ->
	    Error
    end.

-spec md5(Beam) ->
        {'ok', {module(), MD5}} | {'error', 'beam_lib', chnk_rsn()} when
      Beam :: beam(),
      MD5 :: binary().

md5(File) ->
    case catch read_significant_chunks(File, md5_chunks()) of
	{ok, {Module, Chunks0}} ->
	    Chunks = filter_funtab(Chunks0),
	    {ok, {Module, erlang:md5([C || {_Id, C} <- Chunks])}};
	Error ->
	    Error
    end.

-spec format_error(Reason) -> io_lib:chars() when
      Reason :: term().

format_error({error, Error}) ->
    format_error(Error);
format_error({error, Module, Error}) ->
    Module:format_error(Error);
format_error({unknown_chunk, File, ChunkName}) ->
    io_lib:format("~p: Cannot find chunk ~p~n", [File, ChunkName]);
format_error({invalid_chunk, File, ChunkId}) ->
    io_lib:format("~p: Invalid contents of chunk ~p~n", [File, ChunkId]);
format_error({not_a_beam_file, File}) ->
    io_lib:format("~p: Not a BEAM file~n", [File]);
format_error({file_error, File, Reason}) ->
    io_lib:format("~p: ~p~n", [File, file:format_error(Reason)]);
format_error({missing_chunk, File, ChunkId}) ->
    io_lib:format("~p: Not a BEAM file: no IFF \"~s\" chunk~n", 
		  [File, ChunkId]);
format_error({invalid_beam_file, File, Pos}) ->
    io_lib:format("~p: Invalid format of BEAM file near byte number ~p~n", 
		  [File, Pos]);
format_error({chunk_too_big, File, ChunkId, Size, Len}) ->
    io_lib:format("~p: Size of chunk \"~s\" is ~p bytes, "
		  "but only ~p bytes could be read~n",
		  [File, ChunkId, Size, Len]);
format_error({chunks_different, Id}) ->
    io_lib:format("Chunk \"~s\" differs in the two files~n", [Id]);
format_error(different_chunks) ->
    "The two files have different chunks\n";
format_error({modules_different, Module1, Module2}) ->
    io_lib:format("Module names ~p and ~p differ in the two files~n", 
		  [Module1, Module2]);
format_error({not_a_directory, Name}) ->
    io_lib:format("~p: Not a directory~n", [Name]);
format_error({key_missing_or_invalid, File, abstract_code}) ->
    io_lib:format("~p: Cannot decrypt abstract code because key is missing or invalid",
		  [File]);
format_error(badfun) ->
    "not a fun or the fun has the wrong arity";
format_error(exists) ->
    "a fun has already been installed";
format_error(E) ->
    io_lib:format("~p~n", [E]).

%% 
%% Exported functions for encrypted debug info.
%%

-type mode()           :: 'des3_cbc'.
-type crypto_fun_arg() :: 'init'
                        | 'clear'
                        | {'debug_info', mode(), module(), file:filename()}.
-type crypto_fun()     :: fun((crypto_fun_arg()) -> term()).

-spec crypto_key_fun(CryptoKeyFun) -> 'ok' | {'error', Reason} when
      CryptoKeyFun :: crypto_fun(),
      Reason :: badfun | exists | term().

crypto_key_fun(F) ->
    call_crypto_server({crypto_key_fun, F}).

-spec clear_crypto_key_fun() -> 'undefined' | {'ok', Result} when
      Result :: 'undefined' | term().

clear_crypto_key_fun() ->
    call_crypto_server(clear_crypto_key_fun).

-spec make_crypto_key(mode(), string()) ->
        {binary(), binary(), binary(), binary()}.

make_crypto_key(des3_cbc, String) ->
    <<K1:8/binary,K2:8/binary>> = First = erlang:md5(String),
    <<K3:8/binary,IVec:8/binary>> = erlang:md5([First|reverse(String)]),
    {K1,K2,K3,IVec}.

%%
%%  Local functions
%%

read_info(File) ->
    try
        {ok, Module, Data} = scan_beam(File, info),
        [if
             is_binary(File) -> {binary, File};
             true -> {file, File}
         end, {module, Module}, {chunks, Data}]
    catch Error -> Error end.

diff_directories(Dir1, Dir2) ->
    {OnlyDir1, OnlyDir2, Diff} = compare_dirs(Dir1, Dir2),
    diff_only(Dir1, OnlyDir1),
    diff_only(Dir2, OnlyDir2),
    foreach(fun(D) -> io:format("** different: ~p~n", [D]) end, Diff),
    ok.

diff_only(_Dir, []) -> 
    ok;
diff_only(Dir, Only) ->
    io:format("Only in ~p: ~p~n", [Dir, Only]).

%% -> {OnlyInDir1, OnlyInDir2, Different} | throw(Error)
compare_dirs(Dir1, Dir2) ->
    R1 = sofs:relation(beam_files(Dir1)),
    R2 = sofs:relation(beam_files(Dir2)),
    F1 = sofs:domain(R1),
    F2 = sofs:domain(R2),
    {O1, Both, O2} = sofs:symmetric_partition(F1, F2),
    OnlyL1 = sofs:image(R1, O1),
    OnlyL2 = sofs:image(R2, O2),
    B1 = sofs:to_external(sofs:restriction(R1, Both)),
    B2 = sofs:to_external(sofs:restriction(R2, Both)),
    Diff = compare_files(B1, B2, []),
    {sofs:to_external(OnlyL1), sofs:to_external(OnlyL2), Diff}.

compare_files([], [], Acc) ->
    lists:reverse(Acc);
compare_files([{_,F1} | R1], [{_,F2} | R2], Acc) ->
    NAcc = case catch cmp_files(F1, F2) of
	       {error, _Mod, _Reason} ->
		   [{F1, F2} | Acc];
	       ok ->
		   Acc
	   end,
    compare_files(R1, R2, NAcc).

beam_files(Dir) ->
    ok = assert_directory(Dir),
    L = filelib:wildcard(filename:join(Dir, "*.beam")),
    [{filename:basename(Path), Path} || Path <- L].

%% -> ok | throw(Error)
cmp_files(File1, File2) ->
    {ok, {M1, L1}} = read_all_but_useless_chunks(File1),
    {ok, {M2, L2}} = read_all_but_useless_chunks(File2),
    if
	M1 =:= M2 ->
	    cmp_lists(L1, L2);
	true ->
	    error({modules_different, M1, M2})
    end.

cmp_lists([], []) ->
    ok;
cmp_lists([{Id, C1} | R1], [{Id, C2} | R2]) ->
    if
	C1 =:= C2 ->
	    cmp_lists(R1, R2);
	true ->
	    error({chunks_different, Id})
    end;
cmp_lists(_, _) ->
    error(different_chunks).
    
strip_rel(Root) ->
    ok = assert_directory(Root),
    strip_fils(filelib:wildcard(filename:join(Root, "lib/*/ebin/*.beam"))).

%% -> {ok, [{Mod, BinaryOrFileName}]} | throw(Error)
strip_fils(Files) ->
    {ok, [begin {ok, Reply} = strip_file(F), Reply end || F <- Files]}.

%% -> {ok, {Mod, FileName}} | {ok, {Mod, binary()}} | throw(Error)
strip_file(File) ->
    {ok, {Mod, Chunks}} = read_significant_chunks(File, significant_chunks()),
    {ok, Stripped0} = build_module(Chunks),
    Stripped = compress(Stripped0),
    case File of
	_ when is_binary(File) ->
	    {ok, {Mod, Stripped}};
	_ ->
	    FileName = beam_filename(File),
	    case file:open(FileName, [raw, binary, write]) of
		{ok, Fd} ->
		    case file:write(Fd, Stripped) of
			ok ->
			    ok = file:close(Fd),
			    {ok, {Mod, FileName}};
			Error ->
			    ok = file:close(Fd),
			    file_error(FileName, Error)
		    end;
		Error ->
		    file_error(FileName, Error)
	    end
    end.

build_module(Chunks0) ->
    Chunks = list_to_binary(build_chunks(Chunks0)),
    Size = byte_size(Chunks),
    0 = Size rem 4, % Assertion: correct padding?
    {ok, <<"FOR1", (Size+4):32, "BEAM", Chunks/binary>>}.

build_chunks([{Id, Data} | Chunks]) ->
    BId = list_to_binary(Id),
    Size = byte_size(Data),
    Chunk = [<<BId/binary, Size:32>>, Data | pad(Size)],
    [Chunk | build_chunks(Chunks)];
build_chunks([]) -> 
    [].

pad(Size) ->
    case Size rem 4 of
	0 -> [];
	Rem -> lists:duplicate(4 - Rem, 0)
    end.

%% -> {ok, {Module, Chunks}} | throw(Error)
read_all_but_useless_chunks(File0) when is_atom(File0);
					is_list(File0);
					is_binary(File0) ->
    File = beam_filename(File0),
    {ok, Module, ChunkIds0} = scan_beam(File, info),
    ChunkIds = [Name || {Name,_,_} <- ChunkIds0,
			not is_useless_chunk(Name)],
    {ok, Module, Chunks} = scan_beam(File, ChunkIds),
    {ok, {Module, lists:reverse(Chunks)}}.

is_useless_chunk("CInf") -> true;
is_useless_chunk(_) -> false.

%% -> {ok, {Module, Chunks}} | throw(Error)
read_significant_chunks(File, ChunkList) ->
    case read_chunk_data(File, ChunkList, [allow_missing_chunks]) of
	{ok, {Module, Chunks0}} ->
	    Mandatory = mandatory_chunks(),
	    Chunks = filter_significant_chunks(Chunks0, Mandatory, File, Module),
	    {ok, {Module, Chunks}}
    end.

filter_significant_chunks([{_, Data}=Pair|Cs], Mandatory, File, Mod)
  when is_binary(Data) ->
    [Pair|filter_significant_chunks(Cs, Mandatory, File, Mod)];
filter_significant_chunks([{Id, missing_chunk}|Cs], Mandatory, File, Mod) ->
    case member(Id, Mandatory) of
	false ->
	    filter_significant_chunks(Cs, Mandatory, File, Mod);
	true ->
	    error({missing_chunk, File, Id})
    end;
filter_significant_chunks([], _, _, _) -> [].

filter_funtab([{"FunT"=Tag, <<L:4/binary, Data0/binary>>}|Cs]) ->
    Data = filter_funtab_1(Data0, <<0:32>>),
    Funtab = <<L/binary, (iolist_to_binary(Data))/binary>>,
    [{Tag, Funtab}|filter_funtab(Cs)];
filter_funtab([H|T]) ->
    [H|filter_funtab(T)];
filter_funtab([]) -> [].

filter_funtab_1(<<Important:20/binary,_OldUniq:4/binary,T/binary>>, Zero) ->
    [Important,Zero|filter_funtab_1(T, Zero)];
filter_funtab_1(Tail, _) when is_binary(Tail) -> [Tail].

read_all_chunks(File0) when is_atom(File0);
			    is_list(File0); 
			    is_binary(File0) ->
    try
        File = beam_filename(File0),
        {ok, Module, ChunkIds0} = scan_beam(File, info),
        ChunkIds = [Name || {Name,_,_} <- ChunkIds0],
        {ok, Module, Chunks} = scan_beam(File, ChunkIds),
        {ok, Module, lists:reverse(Chunks)}
    catch Error -> Error end.

read_chunk_data(File0, ChunkNames) ->
    try read_chunk_data(File0, ChunkNames, [])
    catch Error -> Error end.

%% -> {ok, {Module, Symbols}} | throw(Error)
read_chunk_data(File0, ChunkNames0, Options)
  when is_atom(File0); is_list(File0); is_binary(File0) ->
    File = beam_filename(File0),
    {ChunkIds, Names} = check_chunks(ChunkNames0, File, [], []),
    AllowMissingChunks = member(allow_missing_chunks, Options),
    {ok, Module, Chunks} = scan_beam(File, ChunkIds, AllowMissingChunks),
    AT = ets:new(beam_symbols, []),
    T = {empty, AT},
    try chunks_to_data(Names, Chunks, File, Chunks, Module, T, [])
    after ets:delete(AT) 
    end.

%% -> {ok, list()} | throw(Error)
check_chunks([ChunkName | Ids], File, IL, L) when is_atom(ChunkName) ->
    ChunkId = chunk_name_to_id(ChunkName, File),
    check_chunks(Ids, File, [ChunkId | IL], [{ChunkId, ChunkName} | L]);
check_chunks([ChunkId | Ids], File, IL, L) -> % when is_list(ChunkId)
    check_chunks(Ids, File, [ChunkId | IL], [{ChunkId, ChunkId} | L]);
check_chunks([], _File, IL, L) ->
    {lists:usort(IL), reverse(L)}.

%% -> {ok, Module, Data} | throw(Error)
scan_beam(File, What) ->
    scan_beam(File, What, false).

%% -> {ok, Module, Data} | throw(Error)
scan_beam(File, What0, AllowMissingChunks) ->
    case scan_beam1(File, What0) of
	{missing, _FD, Mod, Data, What} when AllowMissingChunks ->
	    {ok, Mod, [{Id, missing_chunk} || Id <- What] ++ Data};
	{missing, FD, _Mod, _Data, What} ->
	    error({missing_chunk, filename(FD), hd(What)});
	R ->
	    R
    end.

%% -> {ok, Module, Data} | throw(Error)
scan_beam1(File, What) ->
    FD = open_file(File),
    case catch scan_beam2(FD, What) of
	Error when error =:= element(1, Error) ->
	    throw(Error);
	R ->
	    R
    end.

scan_beam2(FD, What) ->
    case pread(FD, 0, 12) of
	{NFD, {ok, <<"FOR1", _Size:32, "BEAM">>}} ->
	    Start = 12,
	    scan_beam(NFD, Start, What, 17, []);
	_Error -> 
	    error({not_a_beam_file, filename(FD)})
    end.

scan_beam(_FD, _Pos, [], Mod, Data) when Mod =/= 17 ->
    {ok, Mod, Data};    
scan_beam(FD, Pos, What, Mod, Data) ->
    case pread(FD, Pos, 8) of
	{_NFD, eof} when Mod =:= 17 ->
	    error({missing_chunk, filename(FD), "Atom"});	    
	{_NFD, eof} when What =:= info ->
	    {ok, Mod, reverse(Data)};
	{NFD, eof} ->
	    {missing, NFD, Mod, Data, What};
	{NFD, {ok, <<IdL:4/binary, Sz:32>>}} ->
	    Id = binary_to_list(IdL),
	    Pos1 = Pos + 8,
	    Pos2 = (4 * trunc((Sz+3) / 4)) + Pos1,
	    get_data(What, Id, NFD, Sz, Pos1, Pos2, Mod, Data);
	{_NFD, {ok, _ChunkHead}} ->
	    error({invalid_beam_file, filename(FD), Pos})
    end.

get_data(Cs, "Atom"=Id, FD, Size, Pos, Pos2, _Mod, Data) ->
    NewCs = del_chunk(Id, Cs),
    {NFD, Chunk} = get_chunk(Id, Pos, Size, FD),
    <<_Num:32, Chunk2/binary>> = Chunk,
    {Module, _} = extract_atom(Chunk2),
    C = case Cs of
	    info -> 
		{Id, Pos, Size};
	    _ -> 
		{Id, Chunk}
	end,
    scan_beam(NFD, Pos2, NewCs, Module, [C | Data]);
get_data(info, Id, FD, Size, Pos, Pos2, Mod, Data) ->
    scan_beam(FD, Pos2, info, Mod, [{Id, Pos, Size} | Data]);
get_data(Chunks, Id, FD, Size, Pos, Pos2, Mod, Data) ->
    {NFD, NewData} = case member(Id, Chunks) of
			 true ->
			     {FD1, Chunk} = get_chunk(Id, Pos, Size, FD),
			     {FD1, [{Id, Chunk} | Data]};
			 false ->
			     {FD, Data}
	      end,
    NewChunks = del_chunk(Id, Chunks),
    scan_beam(NFD, Pos2, NewChunks, Mod, NewData).
     
del_chunk(_Id, info) ->
    info;
del_chunk(Id, Chunks) ->
    delete(Id, Chunks).

%% -> {NFD, binary()} | throw(Error)
get_chunk(Id, Pos, Size, FD) ->
    case pread(FD, Pos, Size) of
	{NFD, eof} when Size =:= 0 -> % cannot happen
	    {NFD, <<>>};
	{_NFD, eof} when Size > 0 ->
	    error({chunk_too_big, filename(FD), Id, Size, 0});
	{_NFD, {ok, Chunk}} when Size > byte_size(Chunk) ->
	    error({chunk_too_big, filename(FD), Id, Size, byte_size(Chunk)});
	{NFD, {ok, Chunk}} -> % when Size =:= size(Chunk)
	    {NFD, Chunk}
    end.

chunks_to_data([{Id, Name} | CNs], Chunks, File, Cs, Module, Atoms, L) ->
    {_Id, Chunk} = lists:keyfind(Id, 1, Chunks),
    {NewAtoms, Ret} = chunk_to_data(Name, Chunk, File, Cs, Atoms, Module),
    chunks_to_data(CNs, Chunks, File, Cs, Module, NewAtoms, [Ret | L]);
chunks_to_data([], _Chunks, _File, _Cs, Module, _Atoms, L) ->
    {ok, {Module, reverse(L)}}.

chunk_to_data(attributes=Id, Chunk, File, _Cs, AtomTable, _Mod) ->
    try
	Term = binary_to_term(Chunk),
	{AtomTable, {Id, attributes(Term)}}
    catch
	error:badarg ->
	    error({invalid_chunk, File, chunk_name_to_id(Id, File)})
    end;
chunk_to_data(compile_info=Id, Chunk, File, _Cs, AtomTable, _Mod) ->
    try
	{AtomTable, {Id, binary_to_term(Chunk)}}
    catch
	error:badarg ->
	    error({invalid_chunk, File, chunk_name_to_id(Id, File)})
    end;
chunk_to_data(abstract_code=Id, Chunk, File, _Cs, AtomTable, Mod) ->
    case Chunk of
	<<>> ->
	    {AtomTable, {Id, no_abstract_code}};
	<<0:8,N:8,Mode0:N/binary,Rest/binary>> ->
	    Mode = list_to_atom(binary_to_list(Mode0)),
	    decrypt_abst(Mode, Mod, File, Id, AtomTable, Rest);
	_ ->
	    case catch binary_to_term(Chunk) of
		{'EXIT', _} ->
		    error({invalid_chunk, File, chunk_name_to_id(Id, File)});
		Term ->
		    {AtomTable, {Id, Term}}
	    end
    end;
chunk_to_data(atoms=Id, _Chunk, _File, Cs, AtomTable0, _Mod) ->
    AtomTable = ensure_atoms(AtomTable0, Cs),
    Atoms = ets:tab2list(AtomTable),
    {AtomTable, {Id, lists:sort(Atoms)}};
chunk_to_data(ChunkName, Chunk, File,
	      Cs, AtomTable, _Mod) when is_atom(ChunkName) ->
    case catch symbols(Chunk, AtomTable, Cs, ChunkName) of
	{ok, NewAtomTable, S} ->
	    {NewAtomTable, {ChunkName, S}};
	{'EXIT', _} ->
	    error({invalid_chunk, File, chunk_name_to_id(ChunkName, File)})
    end;
chunk_to_data(ChunkId, Chunk, _File, 
	      _Cs, AtomTable, _Module) when is_list(ChunkId) ->
    {AtomTable, {ChunkId, Chunk}}. % Chunk is a binary

chunk_name_to_id(atoms, _)           -> "Atom";
chunk_name_to_id(indexed_imports, _) -> "ImpT";
chunk_name_to_id(imports, _)         -> "ImpT";
chunk_name_to_id(exports, _)         -> "ExpT";
chunk_name_to_id(labeled_exports, _) -> "ExpT";
chunk_name_to_id(locals, _)          -> "LocT";
chunk_name_to_id(labeled_locals, _)  -> "LocT";
chunk_name_to_id(attributes, _)      -> "Attr";
chunk_name_to_id(abstract_code, _)   -> "Abst";
chunk_name_to_id(compile_info, _)    -> "CInf";
chunk_name_to_id(Other, File) -> 
    error({unknown_chunk, File, Other}).

%% Extract attributes

attributes(Attrs) ->
    attributes(keysort(1, Attrs), []).

attributes([], R) ->
    reverse(R);
attributes(L, R) ->
    K = element(1, hd(L)),
    {L1, L2} = splitwith(fun(T) -> element(1, T) =:= K end, L),
    V = append([A || {_, A} <- L1]),
    attributes(L2, [{K, V} | R]).

%% Extract symbols

symbols(<<_Num:32, B/binary>>, AT0, Cs, Name) ->
    AT = ensure_atoms(AT0, Cs),
    symbols1(B, AT, Name, [], 1).

symbols1(<<I1:32, I2:32, I3:32, B/binary>>, AT, Name, S, Cnt) ->
    Symbol = symbol(Name, AT, I1, I2, I3, Cnt),
    symbols1(B, AT, Name, [Symbol|S], Cnt+1);
symbols1(<<>>, AT, _Name, S, _Cnt) ->
    {ok, AT, sort(S)}.

symbol(indexed_imports, AT, I1, I2, I3, Cnt) ->
    {Cnt, atm(AT, I1), atm(AT, I2), I3};
symbol(imports, AT, I1, I2, I3, _Cnt) ->
    {atm(AT, I1), atm(AT, I2), I3};
symbol(labeled_exports, AT, I1, I2, I3, _Cnt) ->
    {atm(AT, I1), I2, I3};
symbol(labeled_locals, AT, I1, I2, I3, _Cnt) ->
    {atm(AT, I1), I2, I3};
symbol(_, AT, I1, I2, _I3, _Cnt) ->
    {atm(AT, I1), I2}.

atm(AT, N) ->
    [{_N, S}] = ets:lookup(AT, N),
    S.

%% AT is updated.
ensure_atoms({empty, AT}, Cs) ->
    {_Id, AtomChunk} = lists:keyfind("Atom", 1, Cs),
    extract_atoms(AtomChunk, AT),
    AT;
ensure_atoms(AT, _Cs) ->
    AT.

extract_atoms(<<_Num:32, B/binary>>, AT) ->
    extract_atoms(B, 1, AT).

extract_atoms(<<>>, _I, _AT) ->
    true;
extract_atoms(B, I, AT) ->
    {Atom, B1} = extract_atom(B),
    true = ets:insert(AT, {I, Atom}),
    extract_atoms(B1, I+1, AT).

extract_atom(<<Len, B/binary>>) ->
    <<SB:Len/binary, Tail/binary>> = B,
    {list_to_atom(binary_to_list(SB)), Tail}.

%%% Utils.

-record(bb, {pos = 0 :: integer(),
	     bin :: binary(),
	     source :: binary() | string()}).

open_file(<<"FOR1",_/binary>>=Binary) ->
    #bb{bin = Binary, source = Binary};
open_file(Binary0) when is_binary(Binary0) ->
    Binary = uncompress(Binary0),
    #bb{bin = Binary, source = Binary};
open_file(FileName) ->
    case file:open(FileName, [read, raw, binary]) of
	{ok, Fd} ->
	    read_all(Fd, FileName, []);
	Error ->
	    file_error(FileName, Error)
    end.

read_all(Fd, FileName, Bins) ->
    case file:read(Fd, 1 bsl 18) of
	{ok, Bin} ->
	    read_all(Fd, FileName, [Bin | Bins]);
	eof ->
	    ok = file:close(Fd),
	    #bb{bin = uncompress(reverse(Bins)), source = FileName};
	Error ->
	    ok = file:close(Fd),
	    file_error(FileName, Error)
    end.

pread(FD, AtPos, Size) ->
    #bb{pos = Pos, bin = Binary} = FD,
    Skip = AtPos-Pos,
    case Binary of
	<<_:Skip/binary, B:Size/binary, Bin/binary>> ->
	    NFD = FD#bb{pos = AtPos+Size, bin = Bin},
	    {NFD, {ok, B}};
	<<_:Skip/binary, Bin/binary>> when byte_size(Bin) > 0 ->
	    NFD = FD#bb{pos = AtPos+byte_size(Bin), bin = <<>>},
	    {NFD, {ok, Bin}};
        _ ->
            {FD, eof}
    end.

filename(BB) when is_binary(BB#bb.source) ->
    BB#bb.source;
filename(BB) -> 
    list_to_atom(BB#bb.source).    

beam_filename(Bin) when is_binary(Bin) ->
    Bin;
beam_filename(File) ->
    filename:rootname(File, ".beam") ++ ".beam".


uncompress(Binary0) ->
    {ok, Fd} = ram_file:open(Binary0, [write, binary]),
    {ok, _} = ram_file:uncompress(Fd),
    {ok, Binary} = ram_file:get_file(Fd),
    ok = ram_file:close(Fd),
    Binary.

compress(Binary0) ->
    {ok, Fd} = ram_file:open(Binary0, [write, binary]),
    {ok, _} = ram_file:compress(Fd),
    {ok, Binary} = ram_file:get_file(Fd),
    ok = ram_file:close(Fd),
    Binary.

%% -> ok | throw(Error)
assert_directory(FileName) ->
    case filelib:is_dir(FileName) of
	true ->
	    ok;
	false ->
	    error({not_a_directory, FileName})
    end.

-spec file_error(file:filename(), {'error',atom()}) -> no_return().

file_error(FileName, {error, Reason}) ->
    error({file_error, FileName, Reason}).

-spec error(term()) -> no_return().

error(Reason) ->
    throw({error, ?MODULE, Reason}).

%% The following chunks must be kept when stripping a BEAM file.

significant_chunks() ->
    ["Line" | md5_chunks()].

%% The following chunks are significant when calculating the MD5
%% for a module. They are listed in the order that they should be MD5:ed.

md5_chunks() ->
    ["Atom", "Code", "StrT", "ImpT", "ExpT", "FunT", "LitT"].

%% The following chunks are mandatory in every Beam file.

mandatory_chunks() ->
    ["Code", "ExpT", "ImpT", "StrT", "Atom"].

%%% ====================================================================
%%% The rest of the file handles encrypted debug info.
%%%
%%% Encrypting the debug info is only useful if you want to
%%% have the debug info available all the time (maybe even in a live
%%% system), but don't want to risk that anyone else but yourself
%%% can use it.
%%% ====================================================================

-record(state, {crypto_key_f :: crypto_fun()}).

-define(CRYPTO_KEY_SERVER, beam_lib__crypto_key_server).

decrypt_abst(Mode, Module, File, Id, AtomTable, Bin) ->
    try
	KeyString = get_crypto_key({debug_info, Mode, Module, File}),
	Key = make_crypto_key(des3_cbc, KeyString),
	Term = decrypt_abst_1(Mode, Key, Bin),
	{AtomTable, {Id, Term}}
    catch
	_:_ ->
	    error({key_missing_or_invalid, File, Id})
    end.

decrypt_abst_1(des3_cbc, {K1, K2, K3, IVec}, Bin) ->
    ok = start_crypto(),
    NewBin = crypto:des3_cbc_decrypt(K1, K2, K3, IVec, Bin),
    binary_to_term(NewBin).

start_crypto() ->
    case crypto:start() of
	{error, {already_started, _}} ->
	    ok;
	ok ->
	    ok
    end.

get_crypto_key(What) ->
    call_crypto_server({get_crypto_key, What}).

call_crypto_server(Req) ->
    try 
	gen_server:call(?CRYPTO_KEY_SERVER, Req, infinity)
    catch
	exit:{noproc,_} ->
	    %% Not started.
	    call_crypto_server_1(Req);
	exit:{normal,_} ->
	    %% The process finished just as we called it.
	    call_crypto_server_1(Req)
    end.

call_crypto_server_1(Req) ->
    gen_server:start({local,?CRYPTO_KEY_SERVER}, ?MODULE, [], []),
    erlang:yield(),
    call_crypto_server(Req).

-spec init([]) -> {'ok', #state{}}.

init([]) ->
    {ok, #state{}}.

-type calls() :: 'clear_crypto_key_fun'
               | {'crypto_key_fun', _}
               | {'get_crypto_key', _}.

-spec handle_call(calls(), {pid(), term()}, #state{}) ->
        {'noreply', #state{}} |
	{'reply', 'error' | {'error','badfun' | 'exists'}, #state{}} |
	{'stop', 'normal', 'undefined' | {'ok', term()}, #state{}}.

handle_call({get_crypto_key, _}=R, From, #state{crypto_key_f=undefined}=S) ->
    case crypto_key_fun_from_file() of
	error ->
	    {reply, error, S};
	F when is_function(F) ->
	    %% The init function for the fun has already been called.
	    handle_call(R, From, S#state{crypto_key_f=F})
    end;
handle_call({get_crypto_key, What}, From, #state{crypto_key_f=F}=S) ->
    try
	Result = F(What),
	%% The result may hold information that we don't want 
	%% lying around. Reply first, then GC, then noreply.
	gen_server:reply(From, Result),
	erlang:garbage_collect(),
	{noreply, S}
    catch
	_:_ ->
	    {reply, error, S}
    end;
handle_call({crypto_key_fun, F}, {_,_} = From, S) ->
    case S#state.crypto_key_f of
	undefined ->
	    %% Don't allow tuple funs here. (They weren't allowed before,
	    %% so there is no reason to allow them now.)
	    if is_function(F), is_function(F, 1) ->
		    {Result, Fun, Reply} = 
			case catch F(init) of
			    ok ->
				{true, F, ok};
			    {ok, F1} when is_function(F1) ->
				if
				    is_function(F1, 1) ->
					{true, F1, ok};
				    true ->
					{false, undefined, 
					 {error, badfun}}
				end;
			    {error, Reason} ->
				{false, undefined, {error, Reason}};
			    {'EXIT', Reason} ->
				{false, undefined, {error, Reason}}
			end,
		    gen_server:reply(From, Reply),
		    erlang:garbage_collect(),
		    NewS = case Result of
			       true ->
				   S#state{crypto_key_f = Fun};
			       false ->
				   S
			   end,
		    {noreply, NewS};
	       true ->
		    {reply, {error, badfun}, S}
	    end;
	OtherF when is_function(OtherF) ->
	    {reply, {error, exists}, S}
    end;
handle_call(clear_crypto_key_fun, _From, S) ->
    case S#state.crypto_key_f of
	undefined ->
	    {stop,normal,undefined,S};
	F ->
	    Result = (catch F(clear)),
	    {stop,normal,{ok,Result},S}
    end.

-spec handle_cast(term(), #state{}) -> {'noreply', #state{}}.

handle_cast(_, State) ->
    {noreply, State}.

-spec handle_info(term(), #state{}) -> {'noreply', #state{}}.

handle_info(_, State) ->
    {noreply, State}.

-spec code_change(term(), #state{}, term()) -> {'ok', #state{}}.

code_change(_OldVsn, State, _Extra) ->
    {ok, State}.

-spec terminate(term(), #state{}) -> 'ok'.

terminate(_Reason, _State) ->
    ok.

crypto_key_fun_from_file() ->
    case init:get_argument(home) of
	{ok,[[Home]]} ->
	    crypto_key_fun_from_file_1([".",Home]);
	_ ->
	    crypto_key_fun_from_file_1(["."])
    end.

crypto_key_fun_from_file_1(Path) ->
    case f_p_s(Path, ".erlang.crypt") of
	{ok, KeyInfo, _} ->
	    try_load_crypto_fun(KeyInfo);
	_ ->
	    error
    end.

f_p_s(P, F) ->
    case file:path_script(P, F) of
	{error, enoent} ->
	    {error, enoent};
	{error, {Line, _Mod, _Term}=E} ->
	    error("file:path_script(~p,~p): error on line ~p: ~s~n",
		  [P, F, Line, file:format_error(E)]),
	    ok;
	{error, E} when is_atom(E) ->
	    error("file:path_script(~p,~p): ~s~n",
		  [P, F, file:format_error(E)]),
	    ok;
	Other ->
	    Other
    end.

try_load_crypto_fun(KeyInfo) when is_list(KeyInfo) ->
    T = ets:new(keys, [private, set]),
    foreach(
      fun({debug_info, Mode, M, Key}) when is_atom(M) ->
	      ets:insert(T, {{debug_info,Mode,M,[]}, Key});
	 ({debug_info, Mode, [], Key}) ->
	      ets:insert(T, {{debug_info, Mode, [], []}, Key});
	 (Other) ->
	      error("unknown key: ~p~n", [Other])
      end, KeyInfo),
    fun({debug_info, Mode, M, F}) ->
	    alt_lookup_key(
	      [{debug_info,Mode,M,F},
	       {debug_info,Mode,M,[]},
	       {debug_info,Mode,[],[]}], T);
       (clear) ->
	    ets:delete(T);
       (_) ->
	    error
    end;
try_load_crypto_fun(KeyInfo) ->
    error("unrecognized crypto key info: ~p\n", [KeyInfo]).

alt_lookup_key([H|T], Tab) ->
    case ets:lookup(Tab, H) of
	[] ->
	    alt_lookup_key(T, Tab);
	[{_, Val}] ->
	    Val
    end;
alt_lookup_key([], _) ->
    error.

error(Fmt, Args) ->
    error_logger:error_msg(Fmt, Args),
    error.