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pdp10_elf36: add support for reading relocation sections

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This commit is contained in:
Mikael Pettersson 2020-03-01 18:01:44 +01:00
parent 0f9e54abbc
commit 800a950210
1 changed files with 67 additions and 1 deletions
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68
erlang/apps/lib/src/pdp10_elf36.erl
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@ -1,7 +1,7 @@
%%% -*- erlang-indent-level: 2 -*-
%%%
%%% I/O of PDP10 Elf36 entities
%%% Copyright (C) 2013-2019 Mikael Pettersson
%%% Copyright (C) 2013-2020 Mikael Pettersson
%%%
%%% This file is part of pdp10-tools.
%%%
@ -21,6 +21,7 @@
-module(pdp10_elf36).
-export([ read_Ehdr/1
, read_RelaTab/2
, read_ShTab/2
, read_SymTab/2
, read_uint36/1
@ -225,6 +226,45 @@ check_Ehdr_e_shentsize(Ehdr) ->
_ -> {error, {?MODULE, {wrong_e_shentsize, ShEntSize}}}
end.
%% I/O of relocation tables ====================================================
-spec read_RelaTab(pdp10_stdio:file(), #elf36_Shdr{})
-> {ok, [#elf36_Rela{}]} | {error, {module(), term()}}.
read_RelaTab(FP, Shdr) ->
#elf36_Shdr{ sh_type = ShType
, sh_size = ShSize
, sh_offset = ShOffset
, sh_entsize = ShEntSize
} = Shdr,
case ShType of
?SHT_RELA ->
case ShEntSize of
?ELF36_RELA_SIZEOF ->
case ShSize rem ?ELF36_RELA_SIZEOF of
0 ->
RelaNum = ShSize div ?ELF36_RELA_SIZEOF,
case RelaNum of
0 -> {ok, []};
_ ->
case pdp10_stdio:fseek(FP, {bof, ShOffset}) of
ok -> read_RelaTab(FP, RelaNum, []);
{error, _Reason} = Error -> Error
end
end;
_ -> {error, {?MODULE, {wrong_relatab_sh_size, ShSize}}}
end;
_ -> {error, {?MODULE, {wrong_relatab_sh_entsize, ShEntSize}}}
end;
_ -> {error, {?MODULE, {wrong_relatab_sh_type, ShType}}}
end.
read_RelaTab(_FP, _RelaNum = 0, Relas) -> {ok, lists:reverse(Relas)};
read_RelaTab(FP, RelaNum, Relas) when RelaNum > 0 ->
case read_Rela(FP) of
{ok, Rela} -> read_RelaTab(FP, RelaNum - 1, [Rela | Relas]);
{error, _Reason} = Error -> Error
end.
%% I/O of ShTab ================================================================
-spec read_ShTab(pdp10_stdio:file(), #elf36_Ehdr{})
@ -400,6 +440,19 @@ read_Sym_name(Sym = #elf36_Sym{st_name = StName}, StrTab) ->
{error, _Reason} = Error -> Error
end.
%% I/O of #elf36_Rela{} ========================================================
read_Rela(FP) -> read_record(FP, elf36_Rela_desc()).
elf36_Rela_desc() ->
#record_desc{ tag = elf36_Rela
, fields =
[ fun read_Addr/1 % r_offset
, fun read_Word/1 % r_info
, fun read_Sword/1 % r_addend
]
}.
%% I/O of #elf36_Shdr{} ========================================================
read_Shdr(FP) -> read_record(FP, elf36_Shdr_desc()).
@ -441,9 +494,16 @@ elf36_Sym_desc() ->
read_Addr(FP) -> read_uint36(FP).
read_Half(FP) -> read_uint18(FP).
read_Off(FP) -> read_uint36(FP).
read_Sword(FP) -> read_sint36(FP).
read_Uchar(FP) -> read_uint9(FP).
read_Word(FP) -> read_uint36(FP).
read_sint36(FP) ->
case read_uint36(FP) of
{ok, UInt36} -> {ok, (UInt36 bxor (1 bsl 35)) - (1 bsl 35)}; % sign-extend
{error, _Reason} = Error -> Error
end.
read_uint9(FP) ->
case pdp10_stdio:fgetc(FP) of
eof -> {error, {?MODULE, eof}};
@ -498,6 +558,12 @@ format_error(Reason) ->
io_lib:format("wrong e_shentsize ~p", [ShEntSize]);
{eof_in_strtab, Index} ->
io_lib:format("premature EOF in string table at index ~p", [Index]);
{wrong_relatab_sh_entsize, ShEntSize} ->
io_lib:format("wrong sh_entsize ~p in relocation table header", [ShEntSize]);
{wrong_relatab_sh_size, ShSize} ->
io_lib:format("wrong sh_size ~p in relocation table header", [ShSize]);
{wrong_relatab_sh_type, ShType} ->
io_lib:format("wrong sh_type ~p in relocation table header", [ShType]);
{wrong_strtab_sh_type, ShType, Index} ->
io_lib:format("wrong sh_type ~p for string table at index ~p",
[ShType, Index]);