ffi: add new methods and error codes

benchmark/ffi/getpid.js

@@ -0,0 +1,25 @@
+'use strict';
+
+const common = require('../common.js');
+const ffi = require('node:ffi');
+
+const bench = common.createBenchmark(main, {
+  n: [1e7],
+}, {
+  flags: ['--experimental-ffi'],
+});
+
+const { lib, functions } = ffi.dlopen(null, {
+  uv_os_getpid: { result: 'i32', parameters: [] },
+});
+
+const getpid = functions.uv_os_getpid;
+
+function main({ n }) {
+  bench.start();
+  for (let i = 0; i < n; ++i)
+    getpid();
+  bench.end(n);
+
+  lib.close();
+}

doc/api/errors.md

@@ -1332,6 +1332,24 @@ added: v14.0.0
 Used when a feature that is not available
 to the current platform which is running Node.js is used.
 
+<a id="ERR_FFI_INVALID_POINTER"></a>
+
+### `ERR_FFI_INVALID_POINTER`
+
+An invalid pointer was passed to an FFI operation.
+
+<a id="ERR_FFI_LIBRARY_CLOSED"></a>
+
+### `ERR_FFI_LIBRARY_CLOSED`
+
+An operation was attempted on an FFI dynamic library after it was closed.
+
+<a id="ERR_FFI_SYSCALL_FAILED"></a>
+
+### `ERR_FFI_SYSCALL_FAILED`
+
+A low-level FFI call failed.
+
 <a id="ERR_FS_CP_DIR_TO_NON_DIR"></a>
 
 ### `ERR_FS_CP_DIR_TO_NON_DIR`

doc/api/ffi.md

@@ -165,12 +165,15 @@ const path = `libsqlite3.${suffix}`;
 added: REPLACEME
 -->
 
-* `path` {string} Path to a dynamic library.
+* `path` {string|null} Path to a dynamic library, or `null` to resolve symbols
+  from the current process image.
 * `definitions` {Object} Symbol definitions to resolve immediately.
 * Returns: {Object}
 
 Loads a dynamic library and resolves the requested function definitions.
 
+On Windows passing `null` is not supported.
+
 When `definitions` is omitted, `functions` is returned as an empty object until
 symbols are resolved explicitly.
 
@@ -237,10 +240,13 @@ Represents a loaded dynamic library.
 
 ### `new DynamicLibrary(path)`
 
-* `path` {string} Path to a dynamic library.
+* `path` {string|null} Path to a dynamic library, or `null` to resolve symbols
+  from the current process image.
 
 Loads the dynamic library without resolving any functions eagerly.
 
+On Windows passing `null` is not supported.
+
 ```cjs
 const { DynamicLibrary } = require('node:ffi');
 
@@ -603,6 +609,55 @@ available storage. This function does not allocate memory on its own.
 
 `buffer` must be a Node.js `Buffer`.
 
+## `ffi.exportArrayBuffer(arrayBuffer, pointer, length)`
+
+<!-- YAML
+added: REPLACEME
+-->
+
+* `arrayBuffer` {ArrayBuffer}
+* `pointer` {bigint}
+* `length` {number}
+
+Copies bytes from an `ArrayBuffer` into native memory.
+
+`length` must be at least `arrayBuffer.byteLength`.
+
+`pointer` must refer to writable native memory with at least `length` bytes of
+available storage. This function does not allocate memory on its own.
+
+## `ffi.exportArrayBufferView(arrayBufferView, pointer, length)`
+
+<!-- YAML
+added: REPLACEME
+-->
+
+* `arrayBufferView` {ArrayBufferView}
+* `pointer` {bigint}
+* `length` {number}
+
+Copies bytes from an `ArrayBufferView` into native memory.
+
+`length` must be at least `arrayBufferView.byteLength`.
+
+`pointer` must refer to writable native memory with at least `length` bytes of
+available storage. This function does not allocate memory on its own.
+
+## `ffi.getRawPointer(source)`
+
+<!-- YAML
+added: REPLACEME
+-->
+
+* `source` {Buffer|ArrayBuffer|ArrayBufferView}
+* Returns: {bigint}
+
+Returns the raw memory address of JavaScript-managed byte storage.
+
+This is unsafe and dangerous. The returned pointer can become invalid if the
+underlying memory is detached, resized, transferred, or otherwise invalidated.
+Using stale pointers can cause memory corruption or process crashes.
+
 ## Safety notes
 
 The `node:ffi` module does not track pointer validity, memory ownership, or

lib/ffi.js

@@ -2,9 +2,13 @@
 
 const {
   ObjectFreeze,
+  ObjectPrototypeToString,
 } = primordials;
 const { Buffer } = require('buffer');
 const { emitExperimentalWarning } = require('internal/util');
+const {
+  isArrayBufferView,
+} = require('internal/util/types');
 const {
   codes: {
     ERR_ACCESS_DENIED,
@@ -32,6 +36,8 @@ const {
   getUint64,
   getFloat32,
   getFloat64,
+  exportBytes,
+  getRawPointer,
   setInt8,
   setUint8,
   setInt16,
@@ -114,21 +120,52 @@ function exportString(str, data, len, encoding = 'utf8') {
   targetBuffer.fill(0, dataLength, dataLength + terminatorSize);
 }
 
-function exportBuffer(buffer, data, len) {
+function exportBuffer(source, data, len) {
   checkFFIPermission();
 
-  if (!Buffer.isBuffer(buffer)) {
-    throw new ERR_INVALID_ARG_TYPE('buffer', 'Buffer', buffer);
+  if (!Buffer.isBuffer(source)) {
+    throw new ERR_INVALID_ARG_TYPE('buffer', 'Buffer', source);
   }
 
   validateInteger(len, 'len', 0);
 
-  if (len < buffer.length) {
-    throw new ERR_OUT_OF_RANGE('len', `>= ${buffer.length}`, len);
+  if (len < source.length) {
+    throw new ERR_OUT_OF_RANGE('len', `>= ${source.length}`, len);
   }
 
-  const targetBuffer = toBuffer(data, len, false);
-  buffer.copy(targetBuffer, 0, 0, buffer.length);
+  exportBytes(source, data, len);
+}
+
+function exportArrayBuffer(source, data, len) {
+  checkFFIPermission();
+
+  if (ObjectPrototypeToString(source) !== '[object ArrayBuffer]') {
+    throw new ERR_INVALID_ARG_TYPE('arrayBuffer', 'ArrayBuffer', source);
+  }
+
+  validateInteger(len, 'len', 0);
+
+  if (len < source.byteLength) {
+    throw new ERR_OUT_OF_RANGE('len', `>= ${source.byteLength}`, len);
+  }
+
+  exportBytes(source, data, len);
+}
+
+function exportArrayBufferView(source, data, len) {
+  checkFFIPermission();
+
+  if (!isArrayBufferView(source)) {
+    throw new ERR_INVALID_ARG_TYPE('arrayBufferView', 'ArrayBufferView', source);
+  }
+
+  validateInteger(len, 'len', 0);
+
+  if (len < source.byteLength) {
+    throw new ERR_OUT_OF_RANGE('len', `>= ${source.byteLength}`, len);
+  }
+
+  exportBytes(source, data, len);
 }
 
 const suffix = process.platform === 'win32' ? 'dll' : process.platform === 'darwin' ? 'dylib' : 'so';
@@ -163,6 +200,8 @@ module.exports = {
   dlopen,
   dlclose,
   dlsym,
+  exportArrayBuffer,
+  exportArrayBufferView,
   exportString,
   exportBuffer,
   getInt8,
@@ -175,6 +214,7 @@ module.exports = {
   getUint64,
   getFloat32,
   getFloat64,
+  getRawPointer,
   setInt8,
   setUint8,
   setInt16,