Making sure that UAC promts fired by the Chromoting plugin get focus (instead of being shown in the…

remoting/host/plugin/daemon_controller_win.cc

Index: remoting/host/plugin/daemon_controller_win.cc
diff --git a/remoting/host/plugin/daemon_controller_win.cc b/remoting/host/plugin/daemon_controller_win.cc
index 678b695629c18124c8affcf9c7ff782832697494..446bcaf813ff840f303b740bafe34d57627e3615 100644
--- a/remoting/host/plugin/daemon_controller_win.cc
+++ b/remoting/host/plugin/daemon_controller_win.cc
@@ -18,6 +18,8 @@
 #include "base/string16.h"
 #include "base/stringize_macros.h"
 #include "base/threading/thread.h"
+#include "base/time.h"
+#include "base/timer.h"
 #include "base/utf_string_conversions.h"
 #include "base/values.h"
 #include "base/win/scoped_bstr.h"
@@ -37,7 +39,7 @@ namespace remoting {
 
 namespace {
 
-// The COM elevation moniker for the elevated controller.
+// The COM elevation moniker for the Elevated Controller.
 const char16 kDaemonControllerElevationMoniker[] =
     TO_L_STRING("Elevation:Administrator!new:")
     TO_L_STRING("ChromotingElevatedController.ElevatedController");
@@ -45,6 +47,9 @@ const char16 kDaemonControllerElevationMoniker[] =
 // Name of the Daemon Controller's worker thread.
 const char kDaemonControllerThreadName[] = "Daemon Controller thread";
 
+// The maximum interval between showing UAC prompts.
+const int kUacTimeoutSec = 15 * 60;

[Jamie, 2012/04/25 21:20:37]

Is this strictly needed as part of this CL? It feels sufficiently complex to
warrant a follow-up.

[alexeypa (please no reviews), 2012/04/25 21:59:24]

I'll move it to a separate CL.

+
 // A base::Thread implementation that initializes COM on the new thread.
 class ComThread : public base::Thread {
  public:
@@ -53,7 +58,8 @@ class ComThread : public base::Thread {
   // Activates an elevated instance of the controller and returns the pointer
   // to the control interface in |control_out|. This class keeps the ownership
   // of the pointer so the caller should not call call AddRef() or Release().
-  HRESULT ActivateElevatedController(IDaemonControl** control_out);
+  HRESULT ActivateElevatedController(void* window_handle,

[Jamie, 2012/04/25 21:20:37]

HWND?

[alexeypa (please no reviews), 2012/04/25 21:59:24]

Done.

+                                     IDaemonControl** control_out);
 
   bool Start();
 
@@ -61,8 +67,13 @@ class ComThread : public base::Thread {
   virtual void Init() OVERRIDE;
   virtual void CleanUp() OVERRIDE;
 
+  void ReleaseElevatedController();
+
   ScopedComPtr<IDaemonControl> control_;
 
+  // This timer is used to release |control_| after a timeout.
+  base::OneShotTimer<ComThread> release_timer_;
+
   DISALLOW_COPY_AND_ASSIGN(ComThread);
 };
 
@@ -79,6 +90,7 @@ class DaemonControllerWin : public remoting::DaemonController {
   virtual void UpdateConfig(scoped_ptr<base::DictionaryValue> config,
                             const CompletionCallback& done_callback) OVERRIDE;
   virtual void Stop(const CompletionCallback& done_callback) OVERRIDE;
+  virtual void SetWindow(void* window_handle) OVERRIDE;
 
  private:
   // Converts a Windows service status code to a Daemon state.
@@ -106,6 +118,10 @@ class DaemonControllerWin : public remoting::DaemonController {
   void DoUpdateConfig(scoped_ptr<base::DictionaryValue> config,
                       const CompletionCallback& done_callback);
   void DoStop(const CompletionCallback& done_callback);
+  void DoSetWindow(void* window_handle);
+
+  // Handle of the plugin window.
+  void* window_handle_;

[Jamie, 2012/04/25 21:20:37]

Store as an HWND?

[alexeypa (please no reviews), 2012/04/25 21:59:24]

Done.

 
   // The worker thread used for servicing long running operations.
   ComThread worker_thread_;
@@ -118,24 +134,17 @@ class DaemonControllerWin : public remoting::DaemonController {
 ComThread::ComThread(const char* name) : base::Thread(name), control_(NULL) {
 }
 
-void ComThread::Init() {
-  CoInitialize(NULL);
-}
-
-void ComThread::CleanUp() {
-  control_.Release();
-  CoUninitialize();
-}
-
 HRESULT ComThread::ActivateElevatedController(
+    void* window_handle,
     IDaemonControl** control_out) {
-  // Chache the instance of Elevated Controller to prevent a UAC prompt on every
-  // operation.
+  // Cache an instance of the Elevated Controller to prevent a UAC prompt on
+  // every operation.
   if (control_.get() == NULL) {
     BIND_OPTS3 bind_options;
     memset(&bind_options, 0, sizeof(bind_options));
     bind_options.cbStruct = sizeof(bind_options);
-    bind_options.hwnd = NULL;
+    bind_options.hwnd =
+        GetTopLevelWindow(reinterpret_cast<HWND>(window_handle));
     bind_options.dwClassContext  = CLSCTX_LOCAL_SERVER;
 
     HRESULT hr = ::CoGetObject(
@@ -146,6 +155,11 @@ HRESULT ComThread::ActivateElevatedController(
     if (FAILED(hr)) {
       return hr;
     }
+
+    // Release |control_| upon expiration of the timeout.
+    release_timer_.Start(FROM_HERE,
+                         base::TimeDelta::FromSeconds(kUacTimeoutSec),
+                         this, &ComThread::ReleaseElevatedController);
   }
 
   *control_out = control_.get();
@@ -158,8 +172,22 @@ bool ComThread::Start() {
   return StartWithOptions(thread_options);
 }
 
+void ComThread::Init() {
+  CoInitialize(NULL);
+}
+
+void ComThread::CleanUp() {
+  ReleaseElevatedController();
+  CoUninitialize();
+}
+
+void ComThread::ReleaseElevatedController() {
+  control_.Release();
+}
+

[Jamie, 2012/04/25 21:20:37]

It's not clear to me which of the previous functions are needed for the UAC
parenting and which are for the timeout, nor why Co[Un]initialize is needed now
and wasn't earlier.

[alexeypa (please no reviews), 2012/04/25 21:59:24]

I'll move the timeout change to a separate CL.
ComThread::Init() & ComThread::CleanUp() were moved to comply with the style
guide. 

 DaemonControllerWin::DaemonControllerWin()
-    : worker_thread_(kDaemonControllerThreadName) {
+    : window_handle_(NULL),
+      worker_thread_(kDaemonControllerThreadName) {
   if (!worker_thread_.Start()) {
     LOG(FATAL) << "Failed to start the Daemon Controller worker thread.";
   }
@@ -227,6 +255,13 @@ void DaemonControllerWin::Stop(const CompletionCallback& done_callback) {
           done_callback));
 }
 
+void DaemonControllerWin::SetWindow(void* window_handle) {
+  worker_thread_.message_loop_proxy()->PostTask(
+      FROM_HERE, base::Bind(
+          &DaemonControllerWin::DoSetWindow, base::Unretained(this),
+          window_handle));
+}
+
 // static
 remoting::DaemonController::State DaemonControllerWin::ConvertToDaemonState(
     DWORD service_state) {
@@ -367,7 +402,8 @@ void DaemonControllerWin::DoInstallAsNeededAndStart(
   DCHECK(worker_thread_.message_loop_proxy()->BelongsToCurrentThread());
 
   IDaemonControl* control = NULL;
-  HRESULT hr = worker_thread_.ActivateElevatedController(&control);
+  HRESULT hr = worker_thread_.ActivateElevatedController(window_handle_,
+                                                         &control);
 
   // Just configure and start the Daemon Controller if it is installed already.
   if (SUCCEEDED(hr)) {
@@ -378,6 +414,7 @@ void DaemonControllerWin::DoInstallAsNeededAndStart(
   // Otherwise, install it if its COM registration entry is missing.
   if (hr == CO_E_CLASSSTRING) {
     scoped_ptr<DaemonInstallerWin> installer = DaemonInstallerWin::Create(
+        window_handle_,
         base::Bind(&DaemonControllerWin::OnInstallationComplete,
                    base::Unretained(this),
                    base::Passed(&config),
@@ -400,7 +437,8 @@ void DaemonControllerWin::DoSetConfigAndStart(
   DCHECK(worker_thread_.message_loop_proxy()->BelongsToCurrentThread());
 
   IDaemonControl* control = NULL;
-  HRESULT hr = worker_thread_.ActivateElevatedController(&control);
+  HRESULT hr = worker_thread_.ActivateElevatedController(window_handle_,
+                                                         &control);
   if (FAILED(hr)) {
     done_callback.Run(HResultToAsyncResult(hr));
     return;
@@ -435,7 +473,8 @@ void DaemonControllerWin::DoUpdateConfig(
   DCHECK(worker_thread_.message_loop_proxy()->BelongsToCurrentThread());
 
   IDaemonControl* control = NULL;
-  HRESULT hr = worker_thread_.ActivateElevatedController(&control);
+  HRESULT hr = worker_thread_.ActivateElevatedController(window_handle_,
+                                                         &control);
   if (FAILED(hr)) {
     done_callback.Run(HResultToAsyncResult(hr));
     return;
@@ -459,7 +498,8 @@ void DaemonControllerWin::DoStop(const CompletionCallback& done_callback) {
   DCHECK(worker_thread_.message_loop_proxy()->BelongsToCurrentThread());
 
   IDaemonControl* control = NULL;
-  HRESULT hr = worker_thread_.ActivateElevatedController(&control);
+  HRESULT hr = worker_thread_.ActivateElevatedController(window_handle_,
+                                                         &control);
   if (FAILED(hr)) {
     done_callback.Run(HResultToAsyncResult(hr));
     return;
@@ -469,6 +509,10 @@ void DaemonControllerWin::DoStop(const CompletionCallback& done_callback) {
   done_callback.Run(HResultToAsyncResult(hr));
 }
 
+void DaemonControllerWin::DoSetWindow(void* window_handle) {
+  window_handle_ = window_handle;
+}
+
 }  // namespace
 
 scoped_ptr<DaemonController> remoting::DaemonController::Create() {