[io/win] Ensure to check if socket is still open when requesting its type.

Fixes #61571
TEST=stdin_cancel_type_test

Change-Id: I5e0a1837e72a6e41a53fc7fe163b8931082e7405
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/451381
Commit-Queue: Alexander Aprelev <[email protected]>
Reviewed-by: Ryan Macnak <[email protected]>

Author: aam

runtime/bin/socket.cc

@@ -953,6 +953,11 @@ void FUNCTION_NAME(Socket_GetFD)(Dart_NativeArguments args) {
 void FUNCTION_NAME(Socket_GetType)(Dart_NativeArguments args) {
   Socket* socket =
       Socket::GetSocketIdNativeField(Dart_GetNativeArgument(args, 0));
+  if (socket->fd() < 0) {
+    OSError os_error(-1, "Socket is closed.", OSError::kUnknown);
+    Dart_SetReturnValue(args, DartUtils::NewDartOSError(&os_error));
+    return;
+  }
   OSError os_error;
   intptr_t type = SocketBase::GetType(socket->fd());
   if (type >= 0) {

runtime/tests/vm/dart/stdin_cancel_type_test.dart

@@ -0,0 +1,13 @@
+// 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.
+//
+// Tests that asking closed stdin for its type doesn't crash.
+// The crash was reported on https://github.com/dart-lang/sdk/issues/61571.
+
+import 'dart:io';
+
+void main() async {
+  stdin.listen((_) {}).cancel();
+  stdin.hasTerminal;
+}