When unpackaged, isolate the monarch by the install path (#15118)

Unpackaged installations don't have the luxury of magic package
isolation to stop them from accidentally touching each other's monarchs.
We need to enforce that ourselves by making their monarch CLSIDs unique
per install.

We'll use a v5 UUID based on the install folder to unique them.

Closes #15117

(cherry picked from commit 5f70920)
Service-Card-Id: 89002000
Service-Version: 1.17

src/cascadia/Remoting/WindowManager.cpp

@@ -12,11 +12,42 @@
 #include "WindowManager.g.cpp"
 #include "../../types/inc/utils.hpp"
 
+#include <WtExeUtils.h>
+
 using namespace winrt;
 using namespace winrt::Microsoft::Terminal;
 using namespace winrt::Windows::Foundation;
 using namespace ::Microsoft::Console;
 
+namespace
+{
+    const GUID& MonarchCLSID()
+    {
+        if (!IsPackaged()) [[unlikely]]
+        {
+            // Unpackaged installations don't have the luxury of magic package isolation
+            // to stop them from accidentally touching each other's monarchs.
+            // We need to enforce that ourselves by making their monarch CLSIDs unique
+            // per install.
+            // This applies in both portable mode and normal unpackaged mode.
+            // We'll use a v5 UUID based on the install folder to unique them.
+            static GUID processRootHashedGuid = []() {
+                // {5456C4DB-557D-4A22-B043-B1577418E4AF}
+                static constexpr GUID processRootHashedGuidBase = { 0x5456c4db, 0x557d, 0x4a22, { 0xb0, 0x43, 0xb1, 0x57, 0x74, 0x18, 0xe4, 0xaf } };
+
+                // Make a temporary monarch CLSID based on the unpackaged install root
+                std::filesystem::path modulePath{ wil::GetModuleFileNameW<std::wstring>(wil::GetModuleInstanceHandle()) };
+                modulePath.remove_filename();
+                std::wstring pathRootAsString{ modulePath.wstring() };
+
+                return Utils::CreateV5Uuid(processRootHashedGuidBase, std::as_bytes(std::span{ pathRootAsString }));
+            }();
+            return processRootHashedGuid;
+        }
+        return Monarch_clsid;
+    }
+}
+
 namespace winrt::Microsoft::Terminal::Remoting::implementation
 {
     WindowManager::WindowManager()
@@ -325,7 +356,7 @@ namespace winrt::Microsoft::Terminal::Remoting::implementation
 
     void WindowManager::_registerAsMonarch()
     {
-        winrt::check_hresult(CoRegisterClassObject(Monarch_clsid,
+        winrt::check_hresult(CoRegisterClassObject(MonarchCLSID(),
                                                    winrt::make<::MonarchFactory>().get(),
                                                    CLSCTX_LOCAL_SERVER,
                                                    REGCLS_MULTIPLEUSE,
@@ -342,7 +373,7 @@ namespace winrt::Microsoft::Terminal::Remoting::implementation
         //
         // * If we're running unpackaged: the .winmd must be a sibling of the .exe
         // * If we're running packaged: the .winmd must be in the package root
-        _monarch = create_instance<Remoting::IMonarch>(Monarch_clsid,
+        _monarch = create_instance<Remoting::IMonarch>(MonarchCLSID(),
                                                        CLSCTX_LOCAL_SERVER);
     }