Implement code:get_object_code/1

Author: FKubisSWM

libs/estdlib/src/code.erl

@@ -31,7 +31,8 @@
     load_binary/3,
     ensure_loaded/1,
     which/1,
-    is_loaded/1
+    is_loaded/1,
+    get_object_code/1
 ]).
 
 %%-----------------------------------------------------------------------------
@@ -132,3 +133,14 @@ which(Module) ->
         {error, _} ->
             non_existing
     end.
+
+%%-----------------------------------------------------------------------------
+%% @param   Module      module to get object code from
+%% @returns Tuple `{Module, Binary, Filename}' if successful, otherwise `error'.
+%% @doc     Return module binary of a given module.
+%% @end
+%%-----------------------------------------------------------------------------
+-spec get_object_code(Module) -> {Module, Binary, Filename} | error when
+    Module :: atom(), Binary :: binary(), Filename :: string().
+get_object_code(_Module) ->
+    erlang:nif_error(undefined).

src/libAtomVM/module.c

@@ -296,6 +296,8 @@ Module *module_new_from_iff_binary(GlobalContext *global, const void *iff_binary
     mod->fun_table = beam_file + offsets[FUNT];
     mod->str_table = beam_file + offsets[STRT];
     mod->str_table_len = sizes[STRT];
+    mod->binary = beam_file;
+    mod->binary_size = size;
     uint32_t num_labels = ENDIAN_SWAP_32(mod->code->labels);
     mod->labels = calloc(num_labels, sizeof(void *));
     if (IS_NULL_PTR(mod->labels)) {

src/libAtomVM/module.h

@@ -103,6 +103,8 @@ struct Module
     const uint8_t *line_refs_table;
     size_t locations_count;
     const uint8_t *locations_table;
+    uint8_t *binary;
+    size_t binary_size;
 
     unsigned int *line_refs_offsets;
     size_t line_refs_offsets_count;

src/libAtomVM/nifs.c

@@ -193,6 +193,7 @@ static term nif_code_all_loaded(Context *ctx, int argc, term argv[]);
 static term nif_code_load_abs(Context *ctx, int argc, term argv[]);
 static term nif_code_load_binary(Context *ctx, int argc, term argv[]);
 static term nif_code_ensure_loaded(Context *ctx, int argc, term argv[]);
+static term nif_code_get_object_code(Context *ctx, int argc, term argv[]);
 static term nif_erlang_module_loaded(Context *ctx, int argc, term argv[]);
 static term nif_erlang_nif_error(Context *ctx, int argc, term argv[]);
 static term nif_lists_reverse(Context *ctx, int argc, term argv[]);
@@ -826,6 +827,11 @@ static const struct Nif code_ensure_loaded_nif =
     .nif_ptr = nif_code_ensure_loaded
 };
 
+static const struct Nif code_get_object_code_nif = {
+    .base.type = NIFFunctionType,
+    .nif_ptr = nif_code_get_object_code
+};
+
 static const struct Nif module_loaded_nif =
 {
     .base.type = NIFFunctionType,
@@ -5408,6 +5414,52 @@ static term nif_code_ensure_loaded(Context *ctx, int argc, term argv[])
     return result;
 }
 
+static term nif_code_get_object_code(Context *ctx, int argc, term argv[])
+{
+    UNUSED(argc);
+    term module_atom = argv[0];
+    VALIDATE_VALUE(module_atom, term_is_atom);
+
+    size_t module_name_len;
+    const uint8_t *module_name = atom_table_get_atom_string(ctx->global->atom_table, term_to_atom_index(module_atom), &module_name_len);
+
+    size_t filename_len = module_name_len + 6;
+    char *module_file_name = malloc(filename_len);
+    if (IS_NULL_PTR(module_file_name)) {
+        return ERROR_ATOM;
+    }
+    memcpy(module_file_name, module_name, module_name_len);
+    memcpy(module_file_name + module_name_len, ".beam", 6);
+    Module *module = globalcontext_load_module_from_avm(ctx->global, module_file_name);
+
+    if (IS_NULL_PTR(module)) {
+        module = sys_load_module_from_file(ctx->global, module_file_name);
+    }
+    if (UNLIKELY(!module)) {
+        free(module_file_name);
+        return ERROR_ATOM;
+    }
+
+    size_t result_size = TUPLE_SIZE(3) + term_binary_heap_size(module->binary_size) + LIST_SIZE(filename_len, 1);
+    if (UNLIKELY(memory_ensure_free_with_roots(ctx, result_size, 1, &module_atom, MEMORY_CAN_SHRINK) != MEMORY_GC_OK)) {
+        free(module_file_name);
+        RAISE_ERROR(OUT_OF_MEMORY_ATOM);
+    }
+    // Note: this assumes constness of module->binary and could be use-after-free if we allowed changing module bitcode at runtime.
+    // TODO: update this code when module unloading will be supported.
+    term binary = term_from_literal_binary((void *) module->binary, module->binary_size, &ctx->heap, ctx->global);
+    // TODO: this code has to be changed to return the complete path
+    term filename_term = term_from_string((const uint8_t *) module_file_name, filename_len, &ctx->heap);
+    term result = term_alloc_tuple(3, &ctx->heap);
+
+    term_put_tuple_element(result, 0, module_atom);
+    term_put_tuple_element(result, 1, binary);
+    term_put_tuple_element(result, 2, filename_term);
+
+    free(module_file_name);
+    return result;
+}
+
 static term nif_erlang_module_loaded(Context *ctx, int argc, term argv[])
 {
     UNUSED(argc);

src/libAtomVM/nifs.gperf

@@ -174,6 +174,7 @@ code:load_binary/3, &code_load_binary_nif
 code:all_available/0, &code_all_available_nif
 code:all_loaded/0, &code_all_loaded_nif
 code:ensure_loaded/1, &code_ensure_loaded_nif
+code:get_object_code/1, &code_get_object_code_nif
 console:print/1, &console_print_nif
 base64:encode/1, &base64_encode_nif
 base64:decode/1, &base64_decode_nif

tests/erlang_tests/CMakeLists.txt

@@ -514,6 +514,7 @@ compile_erlang(test_code_all_available_loaded)
 compile_erlang(test_code_load_binary)
 compile_erlang(test_code_load_abs)
 compile_erlang(test_code_ensure_loaded)
+compile_erlang(test_code_get_object_code)
 compile_erlang(test_add_avm_pack_binary)
 compile_erlang(test_add_avm_pack_file)
 compile_erlang(test_close_avm_pack)
@@ -1035,6 +1036,7 @@ add_custom_target(erlang_test_modules DEPENDS
 
     test_code_all_available_loaded.beam
     test_code_load_binary.beam
+    test_code_get_object_code.beam
     test_code_load_abs.beam
     test_code_ensure_loaded.beam
     test_add_avm_pack_binary.beam

tests/erlang_tests/test_code_get_object_code.erl

@@ -0,0 +1,65 @@
+%
+% This file is part of AtomVM.
+%
+% Copyright 2025 Franciszek Kubis <[email protected]>
+%
+% 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.
+%
+% SPDX-License-Identifier: Apache-2.0 OR LGPL-2.1-or-later
+%
+
+-module(test_code_get_object_code).
+
+-export([start/0, get_object_wrong_argument/1]).
+
+-include("code_load/export_test_module_data.hrl").
+
+start() ->
+    ok = get_object_from_export_test_module(),
+    ok = get_object_from_already_loaded_test_module(),
+    ok = get_object_from_non_existing_module(),
+    ok = ?MODULE:get_object_wrong_argument("a string"),
+    ok = ?MODULE:get_object_wrong_argument(123),
+    ok = ?MODULE:get_object_wrong_argument({1, "a"}),
+    ok = ?MODULE:get_object_wrong_argument([1, b, 3]),
+    0.
+
+get_object_from_already_loaded_test_module() ->
+    {test_code_get_object_code, Bin, _Filename} = code:get_object_code(?MODULE),
+    {module, ?MODULE} = code:load_binary(
+        ?MODULE, atom_to_list(?MODULE) ++ ".beam", Bin
+    ),
+    {module, ?MODULE} = code:ensure_loaded(?MODULE),
+    ok.
+
+get_object_from_export_test_module() ->
+    Bin = ?EXPORT_TEST_MODULE_DATA,
+    error = code:get_object_code(export_test_module),
+    {module, export_test_module} = code:load_binary(
+        export_test_module, "export_test_module.beam", Bin
+    ),
+    {module, export_test_module} = code:ensure_loaded(export_test_module),
+    error = code:get_object_code(export_test_module),
+    24 = export_test_module:exported_func(4),
+    ok.
+
+get_object_from_non_existing_module() ->
+    error = code:get_object_code(non_existing_module),
+    ok.
+
+get_object_wrong_argument(Argument) ->
+    try code:get_object_code(Argument) of
+        _ -> not_raised
+    catch
+        _:_ -> ok
+    end.

tests/test.c

@@ -543,6 +543,7 @@ struct Test tests[] = {
 
     TEST_CASE(test_code_all_available_loaded),
     TEST_CASE_EXPECTED(test_code_load_binary, 24),
+    TEST_CASE(test_code_get_object_code),
     TEST_CASE_EXPECTED(test_code_load_abs, 24),
     TEST_CASE(test_code_ensure_loaded),
     TEST_CASE_ATOMVM_ONLY(test_add_avm_pack_binary, 24),