From e98cdbb8b673a6f3307c903c14cd8b8e72badc60 Mon Sep 17 00:00:00 2001
From: Brad Fitzpatrick <bradfitz@tailscale.com>
Date: Fri, 26 Feb 2021 20:42:00 -0800
Subject: [PATCH] util/winutil: add little Windows utility package

Code from Alex Brainman, split out of another change. I changed it to
a comma-ok return and tweaked the docs a bit.
---
 util/winutil/winutil.go | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)
 create mode 100644 util/winutil/winutil.go

diff --git a/util/winutil/winutil.go b/util/winutil/winutil.go
new file mode 100644
index 000000000..cf6abb450
--- /dev/null
+++ b/util/winutil/winutil.go
@@ -0,0 +1,21 @@
+// Copyright (c) 2021 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build windows
+
+// Package winuntil contains misc Windows/win32 helper functions.
+package winutil
+
+// GetDesktopPID searches the PID of the process that's running the
+// currently active desktop and whether it was found.
+// Usually the PID will be for explorer.exe.
+func GetDesktopPID() (pid uint32, ok bool) {
+	hwnd := windows.GetShellWindow()
+	if hwnd == 0 {
+		return 0, false
+	}
+	var pid uint32
+	windows.GetWindowThreadProcessId(hwnd, &pid)
+	return pid, pid != 0
+}