[io] Avoid uncatchable error in RawDatagramSocket.bind()

Currently the error happens very late in C code which throws
a `Dart_NewApiError()` which isn't catchable via try/catch in
Dart.

Our `dart:io` APIs should never result in uncatchable
errors being thrown.

This CL adds the verification that the address is a IPv4/IPv6
address (and not a unix domain socket address) before actually
binding the code.

Issue #60421

TEST=standalone/io/datagram_error_test

Change-Id: I0ead36b8c90dd8b04523f9e64d3be63a8e66a56c
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/438140
Commit-Queue: Martin Kustermann <[email protected]>
Reviewed-by: Slava Egorov <[email protected]>

Author: mkustermann

sdk/lib/_internal/vm/bin/socket_patch.dart

@@ -1241,6 +1241,13 @@ base class _NativeSocket extends _NativeSocketNativeWrapper
 
     final address = await _resolveHost(host);
 
+    if (address.type != InternetAddressType.IPv6 &&
+        address.type != InternetAddressType.IPv4) {
+      throw SocketException(
+        'Cannot bind datagram socket on non-IPv4/IPv6 address (was: $address)',
+      );
+    }
+
     var socket = _NativeSocket.datagram(address);
     var result = socket._nativeCreateBindDatagram(
       address._in_addr,

tests/standalone/io/datagram_error.dart

@@ -1,31 +1,24 @@
 // Copyright (c) 2025, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
-//
-// Dart test program for testing error path in datagram bind call.
-//
-// OtherResources=datagram_error.dart
 
 import 'dart:io';
 
+import "package:async_helper/async_helper.dart";
 import "package:expect/expect.dart";
-import 'package:path/path.dart' as path;
 
 void main() async {
-  var sdkPath = path.absolute(path.dirname(Platform.executable));
-  var dartPath = path.absolute(
-    sdkPath,
-    Platform.isWindows ? 'dart.exe' : 'dart',
-  );
-  // Get the Dart script file that generates output.
-  var scriptFile = new File(
-    Platform.script.resolve("datagram_error.dart").toFilePath(),
-  );
-  var args = <String>[scriptFile.path];
-  ProcessResult syncResult = Process.runSync(dartPath, args);
-  Expect.notEquals(0, syncResult.exitCode);
-  Expect.stringEquals(
-    syncResult.stderr,
-    "Unexpected type for socket address" + Platform.lineTerminator,
+  SocketException? error;
+  try {
+    await RawDatagramSocket.bind(
+      InternetAddress('/tmp/test_socket', type: InternetAddressType.unix),
+      0,
+    );
+  } on SocketException catch (e) {
+    error = e;
+  }
+  Expect.contains(
+    'Cannot bind datagram socket on non-IPv4/IPv6 address',
+    '$error',
   );
 }