wasi.c
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wasi.c
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	#include <stdio.h>
	#include <stdlib.h>
	#include <string.h>

	#include "ant.h"
	#include "errors.h"
	#include "internal.h"

	#include "ptr.h"
	#include "gc/roots.h"
	#include "modules/buffer.h"
	#include "modules/wasi.h"
	#include "wasm_c_api.h"
	#include "wasm_export.h"

	#define WASM_MAX_PARAMS 32
	#define WASM_MAX_ARGS 256

	enum {
	WASI_INSTANCE_TAG = 0x57415349u, // WASI
	WASI_FUNC_TAG = 0x57415346u, // WASF
	};

	typedef struct {
	uint8_t *binary;
	wasm_module_t module;
	wasm_module_inst_t inst;
	wasm_exec_env_t exec_env;
	} wasi_instance_handle_t;

	typedef struct {
	ant_t *js;
	wasm_module_inst_t inst;
	wasm_exec_env_t exec_env;
	wasm_function_inst_t func;
	} wasi_func_env_t;

	enum {
	WASM_SECTION_IMPORT = 2,
	WASM_SECTION_EXPORT = 7,
	};

	static bool wasm_read_u32_leb(const uint8_t buf, size_t len, size_t offset, uint32_t *out) {
	uint32_t value = 0;
	uint32_t shift = 0;

	while (*offset < len && shift < 35) {
	uint8_t byte = buf[(*offset)++];
	value \|= (uint32_t)(byte & 0x7f) << shift;

	if ((byte & 0x80) == 0) {
	*out = value;
	return true;
	}

	shift += 7;
	}

	return false;
	}

	static bool wasm_read_name(const uint8_t buf, size_t len, size_t offset, const uint8_t *data, uint32_t name_len) {
	uint32_t size = 0;

	if (
	!wasm_read_u32_leb(buf, len, offset, &size)
	\|\| *offset + size > len
	) return false;

	data = buf + offset;
	*name_len = size;
	*offset += size;

	return true;
	}

	static bool wasm_name_equals(const uint8_t data, uint32_t len, const char expected) {
	size_t expected_len = strlen(expected);
	return len == expected_len && memcmp(data, expected, expected_len) == 0;
	}

	static bool wasi_bytes_have_wasi_imports(const uint8_t *wasm_bytes, size_t wasm_len) {
	size_t offset = 8;

	if (!wasm_bytes \|\| wasm_len < 8 \|\| memcmp(wasm_bytes, "\0asm\x01\0\0\0", 8) != 0)
	return false;

	while (offset < wasm_len) {
	uint8_t section_id = wasm_bytes[offset++];
	uint32_t section_size = 0;
	const uint8_t *section;
	size_t section_offset = 0;
	size_t section_len;

	if (
	!wasm_read_u32_leb(wasm_bytes, wasm_len, &offset, &section_size)
	\|\| offset + section_size > wasm_len
	) return false;

	section = wasm_bytes + offset;
	section_len = section_size;
	offset += section_size;

	if (section_id != WASM_SECTION_IMPORT) continue;
	if (!wasm_read_u32_leb(section, section_size, &section_offset, &section_size))
	return false;

	for (uint32_t i = 0; i < section_size; i++) {
	const uint8_t *module_name = NULL;
	const uint8_t *field_name = NULL;
	uint32_t module_name_len = 0;
	uint32_t field_name_len = 0;
	uint32_t discard = 0;
	uint32_t flags = 0;

	if (!wasm_read_name(section, section_len, &section_offset, &module_name, &module_name_len)
	\|\| !wasm_read_name(section, section_len, &section_offset, &field_name, &field_name_len)
	\|\| section_offset >= section_len)
	return false;

	if (wasm_name_equals(module_name, module_name_len, "wasi_snapshot_preview1"))
	return true;

	switch (section[section_offset++]) {
	case 0:
	if (!wasm_read_u32_leb(section, section_len, &section_offset, &discard))
	return false;
	break;
	case 1: {
	if (section_offset >= section_len) return false;
	section_offset++;
	if (!wasm_read_u32_leb(section, section_len, &section_offset, &flags)
	\|\| !wasm_read_u32_leb(section, section_len, &section_offset, &discard))
	return false;
	if ((flags & 0x1) != 0
	&& !wasm_read_u32_leb(section, section_len, &section_offset, &discard))
	return false;
	break;
	}
	case 2:
	if (!wasm_read_u32_leb(section, section_len, &section_offset, &flags)
	\|\| !wasm_read_u32_leb(section, section_len, &section_offset, &discard))
	return false;
	if ((flags & 0x1) != 0
	&& !wasm_read_u32_leb(section, section_len, &section_offset, &discard))
	return false;
	break;
	case 3:
	if (section_offset + 2 > section_len) return false;
	section_offset += 2;
	break;
	default:
	return false;
	}
	}
	}

	return false;
	}

	static bool wasi_bytes_have_command_or_reactor_entry(const uint8_t *wasm_bytes, size_t wasm_len) {
	size_t offset = 8;

	if (!wasm_bytes \|\| wasm_len < 8 \|\| memcmp(wasm_bytes, "\0asm\x01\0\0\0", 8) != 0)
	return false;

	while (offset < wasm_len) {
	uint8_t section_id = wasm_bytes[offset++];
	uint32_t section_size = 0;
	const uint8_t *section;
	size_t section_offset = 0;
	size_t section_len;

	if (!wasm_read_u32_leb(wasm_bytes, wasm_len, &offset, &section_size)
	\|\| offset + section_size > wasm_len)
	return false;

	section = wasm_bytes + offset;
	section_len = section_size;
	offset += section_size;

	if (section_id != WASM_SECTION_EXPORT) continue;
	if (!wasm_read_u32_leb(section, section_len, &section_offset, &section_size))
	return false;

	for (uint32_t i = 0; i < section_size; i++) {
	const uint8_t *name = NULL;
	uint32_t name_len = 0;
	uint32_t discard = 0;

	if (!wasm_read_name(section, section_len, &section_offset, &name, &name_len)
	\|\| section_offset >= section_len)
	return false;

	if (section[section_offset++] != 0) {
	if (!wasm_read_u32_leb(section, section_len, &section_offset, &discard))
	return false;
	continue;
	}

	if (!wasm_read_u32_leb(section, section_len, &section_offset, &discard))
	return false;

	if (wasm_name_equals(name, name_len, "_start")
	\|\| wasm_name_equals(name, name_len, "_initialize"))
	return true;
	}
	}

	return false;
	}

	static inline bool wasi_is_proc_exit_exception(const char *exception) {
	return exception != NULL && strstr(exception, "wasi proc exit") != NULL;
	}

	static ant_value_t wasi_handle_proc_exit(wasm_module_inst_t inst) {
	uint32_t exit_code = wasm_runtime_get_wasi_exit_code(inst);
	wasm_runtime_clear_exception(inst);
	if (exit_code != 0) exit((int)exit_code);
	return js_mkundef();
	}

	static ant_value_t wasi_exported_func_call(ant_t js, ant_value_t args, int nargs) {
	if (!js_check_native_tag(js->current_func, WASI_FUNC_TAG))
	return js_mkerr(js, "Invalid WASI function");
	wasi_func_env_t env = (wasi_func_env_t )js_get_native_ptr(js->current_func);

	uint32_t param_count = wasm_func_get_param_count(env->func, env->inst);
	uint32_t result_count = wasm_func_get_result_count(env->func, env->inst);
	if (param_count > WASM_MAX_PARAMS) param_count = WASM_MAX_PARAMS;

	uint32_t wasm_argv[WASM_MAX_PARAMS];
	memset(wasm_argv, 0, sizeof(wasm_argv));

	for (int i = 0; i < nargs && (uint32_t)i < param_count; i++) {
	wasm_argv[i] = (uint32_t)js_getnum(args[i]);
	}

	if (!wasm_runtime_call_wasm(env->exec_env, env->func, param_count, wasm_argv)) {
	const char *exception = wasm_runtime_get_exception(env->inst);
	if (wasi_is_proc_exit_exception(exception)) return wasi_handle_proc_exit(env->inst);
	return js_mkerr(js, "%s", exception ? exception : "WASI function call failed");
	}

	if (result_count == 0) return js_mkundef();
	return js_mknum((double)(int32_t)wasm_argv[0]);
	}

	static void wasi_func_finalize(ant_t js, ant_object_t obj) {
	if (obj->native.tag != WASI_FUNC_TAG) return;

	free(obj->native.ptr);
	obj->native.ptr = NULL;
	obj->native.tag = 0;
	}

	static void wasi_instance_finalize(ant_t js, ant_object_t obj) {
	if (obj->native.tag != WASI_INSTANCE_TAG) return;
	wasi_instance_handle_t handle = (wasi_instance_handle_t )obj->native.ptr;

	if (!handle) return;
	if (handle->exec_env) wasm_runtime_destroy_exec_env(handle->exec_env);
	if (handle->inst) wasm_runtime_deinstantiate(handle->inst);
	if (handle->module) wasm_runtime_unload(handle->module);

	free(handle->binary);
	free(handle);
	}

	bool wasi_module_has_wasi_imports(void *c_api_module) {
	wasm_importtype_vec_t import_types = {0};
	wasm_module_imports((wasm_module_t *)c_api_module, &import_types);

	bool has_wasi = false;
	for (size_t i = 0; i < import_types.size; i++) {
	const wasm_name_t *mod = wasm_importtype_module(import_types.data[i]);
	if (mod && mod->size >= 22 && memcmp(mod->data, "wasi_snapshot_preview1", 22) == 0) {
	has_wasi = true;
	break;
	}}

	wasm_importtype_vec_delete(&import_types);
	return has_wasi;
	}

	bool wasi_module_is_command_or_reactor(void *c_api_module) {
	wasm_exporttype_vec_t export_types = {0};
	bool has_entry = false;

	wasm_module_exports((wasm_module_t *)c_api_module, &export_types);

	for (size_t i = 0; i < export_types.size; i++) {
	const wasm_name_t *name = wasm_exporttype_name(export_types.data[i]);
	const wasm_externtype_t *type = wasm_exporttype_type(export_types.data[i]);
	const wasm_functype_t *func_type;
	size_t name_len;

	if (!name \|\| wasm_externtype_kind(type) != WASM_EXTERN_FUNC) continue;
	name_len = name->size;
	if (name_len > 0 && name->data[name_len - 1] == '\0') name_len--;

	if (!((name_len == 6 && memcmp(name->data, "_start", 6) == 0)
	\|\| (name_len == 11 && memcmp(name->data, "_initialize", 11) == 0)))
	continue;

	func_type = wasm_externtype_as_functype_const(type);
	if (!func_type) continue;
	if (wasm_functype_params(func_type)->size == 0 && wasm_functype_results(func_type)->size == 0) {
	has_entry = true;
	break;
	}
	}

	wasm_exporttype_vec_delete(&export_types);
	return has_entry;
	}

	bool wasi_bytes_need_wasi_command_warning_suppression(const uint8_t *wasm_bytes, size_t wasm_len) {
	return wasi_bytes_have_wasi_imports(wasm_bytes, wasm_len)
	&& !wasi_bytes_have_command_or_reactor_entry(wasm_bytes, wasm_len);
	}

	static void wasi_bind_func_export(
	ant_t *js, ant_value_t exports_obj, ant_value_t instance_obj,
	wasm_module_inst_t inst, wasm_exec_env_t exec_env, const char *name
	) {
	wasm_function_inst_t func = wasm_runtime_lookup_function(inst, name);
	if (!func) return;

	wasi_func_env_t fenv = calloc(1, sizeof(fenv));
	if (!fenv) return;
	fenv->js = js;
	fenv->inst = inst;
	fenv->exec_env = exec_env;
	fenv->func = func;

	GC_ROOT_SAVE(root_mark, js);
	ant_value_t obj = js_mkobj(js);
	GC_ROOT_PIN(js, obj);

	js_set_slot(obj, SLOT_CFUNC, js_mkfun(wasi_exported_func_call));
	js_set_native_ptr(obj, fenv);
	js_set_native_tag(obj, WASI_FUNC_TAG);
	js_set_slot_wb(js, obj, SLOT_ENTRIES, instance_obj);
	js_set_finalizer(obj, wasi_func_finalize);
	js_set(js, exports_obj, name, js_obj_to_func(obj));
	GC_ROOT_RESTORE(js, root_mark);
	}

	static void wasi_bind_memory_export(
	ant_t *js, ant_value_t exports_obj, ant_value_t instance_obj,
	wasm_module_inst_t inst, const char *name
	) {
	void *mem_data = wasm_runtime_addr_app_to_native(inst, 0);
	if (!mem_data) return;

	wasm_memory_inst_t mem = wasm_runtime_get_default_memory(inst);
	uint64_t pages = mem ? wasm_memory_get_cur_page_count(mem) : 0;
	size_t mem_size = (size_t)(pages * 65536);

	ArrayBufferData *buffer = calloc(1, sizeof(ArrayBufferData));
	if (!buffer) return;

	buffer->data = (uint8_t *)mem_data;
	buffer->length = mem_size;
	buffer->capacity = mem_size;
	buffer->ref_count = 1;

	ant_value_t ab = create_arraybuffer_obj(js, buffer);
	ant_value_t mem_obj = js_mkobj(js);
	js_set_slot_wb(js, mem_obj, SLOT_DATA, ab);
	js_set_slot_wb(js, mem_obj, SLOT_CTOR, instance_obj);
	js_set(js, exports_obj, name, mem_obj);
	}

	ant_value_t wasi_instantiate(
	ant_t js, const uint8_t wasm_bytes, size_t wasm_len,
	ant_value_t module_obj, ant_value_t wasi_opts
	) {
	char error_buf[128] = {0};
	uint8_t *bin_copy = malloc(wasm_len);

	if (!bin_copy) return js_mkerr(js, "out of memory");
	memcpy(bin_copy, wasm_bytes, wasm_len);

	wasm_module_t rt_module = wasm_runtime_load(bin_copy, (uint32_t)wasm_len, error_buf, sizeof(error_buf));
	if (!rt_module) {
	free(bin_copy);
	return js_mkerr(js, "%s", error_buf[0] ? error_buf : "Failed to load WASI module");
	}

	const char *dirs[] = { "." };
	ant_value_t args_val = is_object_type(wasi_opts)
	? js_get(js, wasi_opts, "args")
	: js_mkundef();

	int argc = vtype(args_val) == T_ARR ? (int)js_arr_len(js, args_val) : 0;
	if (argc < 1) argc = 1;
	if (argc > WASM_MAX_ARGS) argc = WASM_MAX_ARGS;

	char *argv[argc];
	if (vtype(args_val) == T_ARR) {
	for (int i = 0; i < argc; i++) {
	char *s = js_getstr(js, js_arr_get(js, args_val, (ant_offset_t)i), NULL);
	argv[i] = s ? s : (char *)"";
	}
	} else argv[0] = (char *)"wasi";

	wasm_runtime_set_wasi_args(rt_module, dirs, 1, NULL, 0, NULL, 0, argv, argc);
	wasm_module_inst_t inst = wasm_runtime_instantiate(rt_module, 512 * 1024, 256 * 1024, error_buf, sizeof(error_buf));

	if (!inst) {
	wasm_runtime_unload(rt_module);
	free(bin_copy);
	return js_mkerr(js, "%s", error_buf[0] ? error_buf : "Failed to instantiate WASI module");
	}

	wasm_exec_env_t exec_env = wasm_runtime_create_exec_env(inst, 512 * 1024);
	if (!exec_env) {
	wasm_runtime_deinstantiate(inst);
	wasm_runtime_unload(rt_module);
	free(bin_copy);
	return js_mkerr(js, "Failed to create WASI exec env");
	}

	wasi_instance_handle_t handle = calloc(1, sizeof(handle));
	if (!handle) {
	wasm_runtime_destroy_exec_env(exec_env);
	wasm_runtime_deinstantiate(inst);
	wasm_runtime_unload(rt_module);
	free(bin_copy);
	return js_mkerr(js, "out of memory");
	}

	handle->binary = bin_copy;
	handle->module = rt_module;
	handle->inst = inst;
	handle->exec_env = exec_env;

	ant_value_t instance_obj = js_mkobj(js);
	ant_value_t exports_obj = js_mkobj(js);

	js_set_native_ptr(instance_obj, handle);
	js_set_native_tag(instance_obj, WASI_INSTANCE_TAG);
	js_set_slot_wb(js, instance_obj, SLOT_CTOR, module_obj);
	js_set_finalizer(instance_obj, wasi_instance_finalize);

	int32_t export_count = wasm_runtime_get_export_count(rt_module);
	for (int32_t i = 0; i < export_count; i++) {
	wasm_export_t export_info;
	wasm_runtime_get_export_type(rt_module, i, &export_info);

	if (export_info.kind == WASM_IMPORT_EXPORT_KIND_FUNC)
	wasi_bind_func_export(js, exports_obj, instance_obj, inst, exec_env, export_info.name);
	else if (export_info.kind == WASM_IMPORT_EXPORT_KIND_MEMORY)
	wasi_bind_memory_export(js, exports_obj, instance_obj, inst, export_info.name);
	}

	js_set_slot_wb(js, instance_obj, SLOT_ENTRIES, exports_obj);
	js_set(js, instance_obj, "exports", exports_obj);

	return instance_obj;
	}

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