Windows: Add ran as admin jumpscare

Author: Vendicated

gui_prerequisites_windows.go

@@ -0,0 +1,70 @@
+//go:build gui || (!gui && !cli)
+
+package main
+
+import (
+	"fmt"
+	"golang.org/x/sys/windows"
+	"syscall"
+	"unsafe"
+)
+
+func init() {
+	if IsAdmin() {
+		const (
+			MB_OKCANCEL        = 0x1
+			MB_ICONEXCLAMATION = 0x30
+
+			IDCANCEL = 2
+		)
+
+		ret, _, _ := syscall.NewLazyDLL("user32.dll").NewProc("MessageBoxW").Call(
+			uintptr(0), // hwnd (NULL)
+			uintptr(unsafe.Pointer(Unwrap(syscall.UTF16PtrFromString(
+				"Run me as a normal user, not administrator!\n"+
+					"If you didn't explicitly run me as Administrator, make sure you don't have UAC set to 'Never Notify'.\n\n"+
+					"VencordInstaller will close once you press OK.\n"+
+					"Alternatively, press Cancel to proceed anyway, but this may cause issues. Only choose this option as a last resort",
+			)))),
+			uintptr(unsafe.Pointer(Unwrap(syscall.UTF16PtrFromString("Do not run me as Administrator")))),
+			uintptr(MB_OKCANCEL|MB_ICONEXCLAMATION), // flags
+		)
+
+		if ret != IDCANCEL {
+			panic("Ran as Administrator")
+		}
+	}
+}
+
+func IsAdmin() bool {
+	// most sane windows code, copy-pasted from https://github.com/golang/go/issues/28804#issuecomment-505326268
+
+	var sid *windows.SID
+
+	// Although this looks scary, it is directly copied from the
+	// official windows documentation. The Go API for this is a
+	// direct wrap around the official C++ API.
+	// See https://docs.microsoft.com/en-us/windows/desktop/api/securitybaseapi/nf-securitybaseapi-checktokenmembership
+	err := windows.AllocateAndInitializeSid(
+		&windows.SECURITY_NT_AUTHORITY,
+		2,
+		windows.SECURITY_BUILTIN_DOMAIN_RID,
+		windows.DOMAIN_ALIAS_RID_ADMINS,
+		0, 0, 0, 0, 0, 0,
+		&sid)
+	if err != nil {
+		fmt.Println("SID Error: ", err)
+		return false
+	}
+	defer windows.FreeSid(sid)
+
+	token := windows.Token(0)
+
+	isMember, err := token.IsMember(sid)
+	if err != nil {
+		fmt.Println("Token Membership Error: ", err)
+		return false
+	}
+
+	return token.IsElevated() || isMember
+}

util.go

@@ -80,3 +80,10 @@ func CheckIfErrIsCauseItsBusyRn(err error) error {
 
 	return err
 }
+
+func Unwrap[T any](v T, err error) T {
+	if err != nil {
+		panic(err)
+	}
+	return v
+}