Implemented on-demand installation of the Chromoting Host on Windows.

remoting/host/plugin/daemon_controller_win.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "remoting/host/plugin/daemon_controller.h"
 
 #include <objbase.h>
 
 #include "base/basictypes.h"
 #include "base/bind.h"
 #include "base/compiler_specific.h"
 #include "base/file_path.h"
 #include "base/file_util.h"
 #include "base/json/json_reader.h"
 #include "base/json/json_writer.h"
 #include "base/logging.h"
+#include "base/synchronization/lock.h"
 #include "base/threading/thread.h"
 #include "base/utf_string_conversions.h"
 #include "base/values.h"
+#include "base/win/scoped_bstr.h"
+#include "base/win/scoped_comptr.h"
 #include "remoting/base/scoped_sc_handle_win.h"
 #include "remoting/host/branding.h"
+#include "remoting/host/plugin/daemon_installer_win.h"
 
 // MIDL-generated declarations and definitions.
 #include "remoting/host/elevated_controller.h"
 
+using base::win::ScopedBstr;
+using base::win::ScopedComPtr;
+
 namespace remoting {
 
 namespace {
 
 // The COM elevation moniker for the elevated controller.
-const char kElevationMoniker[] = "Elevation:Administrator!new:"
-    "{430a9403-8176-4733-afdc-0b325a8fda84}";
+const char kDaemonControllerElevationMoniker[] = "Elevation:Administrator!new:"
+    "ChromotingElevatedController.ElevatedController";
 
 // Name of the Daemon Controller's worker thread.
 const char kDaemonControllerThreadName[] = "Daemon Controller thread";
 
 // A base::Thread implementation that initializes COM on the new thread.
 class ComThread : public base::Thread {
  public:
   explicit ComThread(const char* name);
 
   // 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);
 
   bool Start();
 
  protected:
   virtual void Init() OVERRIDE;
   virtual void CleanUp() OVERRIDE;
 
-  IDaemonControl* control_;
+  ScopedComPtr<IDaemonControl> control_;
 
   DISALLOW_COPY_AND_ASSIGN(ComThread);
 };
 
 class DaemonControllerWin : public remoting::DaemonController {
  public:
   DaemonControllerWin();
   virtual ~DaemonControllerWin();
 
   virtual State GetState() OVERRIDE;
   virtual void GetConfig(const GetConfigCallback& callback) OVERRIDE;
   virtual void SetConfigAndStart(
       scoped_ptr<base::DictionaryValue> config,
       const CompletionCallback& done_callback) OVERRIDE;
   virtual void UpdateConfig(scoped_ptr<base::DictionaryValue> config,
                             const CompletionCallback& done_callback) OVERRIDE;
   virtual void Stop(const CompletionCallback& done_callback) OVERRIDE;
 
  private:
   // Converts a Windows service status code to a Daemon state.
   static State ConvertToDaemonState(DWORD service_state);
 
   // Converts HRESULT to the AsyncResult.
   static AsyncResult HResultToAsyncResult(HRESULT hr);
 
+  // Procedes with the daemon configuration if the installation succeeded,
+  // otherwise reports the error.
+  void OnInstallationComplete(HRESULT result);
+
   // Opens the Chromoting service returning its handle in |service_out|.
   DWORD OpenService(ScopedScHandle* service_out);
 
   // The functions that actually do the work. They should be called in
   // the context of |worker_thread_|;
   void DoGetConfig(const GetConfigCallback& callback);
+  void DoInstall(scoped_ptr<base::DictionaryValue> config,
+                 const CompletionCallback& done_callback);
   void DoSetConfigAndStart(scoped_ptr<base::DictionaryValue> config,
                            const CompletionCallback& done_callback);
   void DoStop(const CompletionCallback& done_callback);
 
   // The worker thread used for servicing long running operations.
   ComThread worker_thread_;
 
+  // The lock protecting the data members below.
+  base::Lock lock_;
+
+  scoped_ptr<base::DictionaryValue> config_;
+  CompletionCallback done_callback_;

[Sergey Ulanov, 2012/04/07 18:09:21]

Since this is used only during installation maybe call it
install_done_callback_?

[alexeypa (please no reviews), 2012/04/09 20:24:11]

It was removed from the class.

+  scoped_ptr<DaemonInstallerWin> installer_;
+
   DISALLOW_COPY_AND_ASSIGN(DaemonControllerWin);
 };
 
 ComThread::ComThread(const char* name) : base::Thread(name), control_(NULL) {
 }
 
 void ComThread::Init() {
   CoInitialize(NULL);
 }
 
 void ComThread::CleanUp() {
-  if (control_ != NULL)
-    control_->Release();
+  control_.Release();
   CoUninitialize();
 }
 
 HRESULT ComThread::ActivateElevatedController(
     IDaemonControl** control_out) {
   // Chache the instance of Elevated Controller to prevent a UAC prompt on every
   // operation.
-  if (control_ == NULL) {
+  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.dwClassContext  = CLSCTX_LOCAL_SERVER;
 
-    HRESULT hr = ::CoGetObject(ASCIIToUTF16(kElevationMoniker).c_str(),
-                               &bind_options,
-                               IID_IDaemonControl,
-                               reinterpret_cast<void**>(&control_));
+    HRESULT hr = ::CoGetObject(
+        ASCIIToUTF16(kDaemonControllerElevationMoniker).c_str(),
+        &bind_options,
+        IID_IDaemonControl,
+        control_.ReceiveVoid());
     if (FAILED(hr)) {
-      LOG(ERROR) << "Failed to create the elevated controller (error: 0x"
-          << std::hex << hr << std::dec << ").";
       return hr;
     }
   }
 
-  *control_out = control_;
+  *control_out = control_.get();
   return S_OK;
 }
 
 bool ComThread::Start() {
   // N.B. The single threaded COM apartment must be run on a UI message loop.
   base::Thread::Options thread_options(MessageLoop::TYPE_UI, 0);
   return StartWithOptions(thread_options);
 }
 
 DaemonControllerWin::DaemonControllerWin()
@@ skipping 20 matching lines @@
         return ConvertToDaemonState(status.dwCurrentState);
       } else {
         LOG_GETLASTERROR(ERROR)
             << "Failed to query the state of the '" << kWindowsServiceName
             << "' service";
         return STATE_UNKNOWN;
       }
       break;
     }
     case ERROR_SERVICE_DOES_NOT_EXIST:
-      return STATE_NOT_IMPLEMENTED;
+      return STATE_NOT_INSTALLED;
     default:
       return STATE_UNKNOWN;
   }
 }
 
 void DaemonControllerWin::GetConfig(const GetConfigCallback& callback) {
   worker_thread_.message_loop_proxy()->PostTask(
       FROM_HERE,
       base::Bind(&DaemonControllerWin::DoGetConfig,
                  base::Unretained(this), callback));
 }
 
 void DaemonControllerWin::SetConfigAndStart(
     scoped_ptr<base::DictionaryValue> config,
     const CompletionCallback& done_callback) {
 
   worker_thread_.message_loop_proxy()->PostTask(
       FROM_HERE, base::Bind(
-          &DaemonControllerWin::DoSetConfigAndStart, base::Unretained(this),
+          &DaemonControllerWin::DoInstall, base::Unretained(this),
           base::Passed(&config), done_callback));
 }
 
 void DaemonControllerWin::UpdateConfig(
     scoped_ptr<base::DictionaryValue> config,
     const CompletionCallback& done_callback) {
   NOTIMPLEMENTED();
   done_callback.Run(RESULT_FAILED);
 }
 
@@ skipping 33 matching lines @@
 }
 
 // static
 DaemonController::AsyncResult DaemonControllerWin::HResultToAsyncResult(
     HRESULT hr) {
   // TODO(sergeyu): Report other errors to the webapp once it knows
   // how to handle them.
   return FAILED(hr) ? RESULT_FAILED : RESULT_OK;
 }
 
+void DaemonControllerWin::OnInstallationComplete(HRESULT result) {
+  scoped_ptr<base::DictionaryValue> config;
+  CompletionCallback done_callback;
+
+  {
+    base::AutoLock lock(lock_);
+    installer_.reset();
+    std::swap(done_callback, done_callback_);
+    config = config_.Pass();
+  }
+
+  if (SUCCEEDED(result)) {
+    DoSetConfigAndStart(config.Pass(), done_callback);
+  } else {
+    LOG(ERROR) << "Failed to install the Chromoting Host "
+               << "(error: 0x" << std::hex << result << std::dec << ").";
+    done_callback.Run(HResultToAsyncResult(result));
+  }
+}
+
 DWORD DaemonControllerWin::OpenService(ScopedScHandle* service_out) {
   // Open the service and query its current state.
   ScopedScHandle scmanager(
       ::OpenSCManagerW(NULL, SERVICES_ACTIVE_DATABASE,
                        SC_MANAGER_CONNECT | SC_MANAGER_ENUMERATE_SERVICE));
   if (!scmanager.IsValid()) {
     DWORD error = GetLastError();
     LOG_GETLASTERROR(ERROR)
         << "Failed to connect to the service control manager";
     return error;
@@ skipping 17 matching lines @@
 
 void DaemonControllerWin::DoGetConfig(const GetConfigCallback& callback) {
   IDaemonControl* control = NULL;
   HRESULT hr = worker_thread_.ActivateElevatedController(&control);
   if (FAILED(hr)) {
     callback.Run(scoped_ptr<base::DictionaryValue>());
     return;
   }
 
   // Get the host configuration.
-  BSTR host_config = NULL;
-  hr = control->GetConfig(&host_config);
+  ScopedBstr host_config;
+  hr = control->GetConfig(host_config.Receive());
   if (FAILED(hr)) {
     callback.Run(scoped_ptr<base::DictionaryValue>());
     return;
   }
 
-  string16 file_content(static_cast<char16*>(host_config),
-                        ::SysStringLen(host_config));
-  SysFreeString(host_config);
+  string16 file_content(static_cast<BSTR>(host_config), host_config.Length());
 
   // Parse the string into a dictionary.
   scoped_ptr<base::Value> config(
       base::JSONReader::Read(UTF16ToUTF8(file_content), true));
 
   base::DictionaryValue* dictionary;
   if (config.get() == NULL || !config->GetAsDictionary(&dictionary)) {
     callback.Run(scoped_ptr<base::DictionaryValue>());
     return;
   }
 
   config.release();
   callback.Run(scoped_ptr<base::DictionaryValue>(dictionary));
 }
 
+void DaemonControllerWin::DoInstall(scoped_ptr<base::DictionaryValue> config,

[Sergey Ulanov, 2012/04/07 18:09:21]

Since this method installs the host only if it isn't installed and then starts
the host, then maybe call it EnsureInstalledAndStart()

[alexeypa (please no reviews), 2012/04/09 20:24:11]

Renamed to DoInstallAsNeededAndStart to preserve "Do" as a way of marking all
worker methods.

+                                    const CompletionCallback& done_callback) {
+  IDaemonControl* control = NULL;
+  HRESULT hr = worker_thread_.ActivateElevatedController(&control);
+
+  // Just configure and start the Daemon Controller if it is installed already.
+  if (SUCCEEDED(hr)) {
+    DoSetConfigAndStart(config.Pass(), done_callback);
+    return;
+  }
+
+  // Otherwise, install it if it's COM registration entry is missing.
+  if (hr == CO_E_CLASSSTRING) {
+    base::AutoLock lock(lock_);
+    DCHECK(!config_.get());
+    DCHECK(!installer_.get());
+
+    hr = DaemonInstallerWin::Create(&installer_);
+    if (SUCCEEDED(hr)) {
+      config_ = config.Pass();

[Sergey Ulanov, 2012/04/07 18:09:21]

Do we really need to store these values as class members? I think we should be
able to pass them directly to OnInstallationComplete().
base::Bind supports currying (http://en.wikipedia.org/wiki/Currying). You can
define OnInstallationComplete as this:
 void OnInstallationComplete(scoped_ptr<DictionaryValue> config,
                             const CompletionCallback& callback,
                             HRESULT hr);
And then when you Bind() it you specify the first two parameters, but not the
last one - that will produce Callback<void(HRESULT)>.

[alexeypa (please no reviews), 2012/04/09 20:24:11]

Done.

I kept installer_ as a class member (instead of passing it to the callback)
though to make sure that the installer will be safely deleted when
DaemonController is destroyed prematurely.

+      done_callback_ = done_callback;
+    }
+  }
+
+  // Run the installer or report the error if any.
+  if (SUCCEEDED(hr)) {
+    installer_->Install(base::Bind(&DaemonControllerWin::OnInstallationComplete,
+                        base::Unretained(this)));

[Sergey Ulanov, 2012/04/07 18:09:21]

nit: not indented properly

[alexeypa (please no reviews), 2012/04/09 20:24:11]

Done.

+  } else {
+    LOG(ERROR) << "Failed to initiate the Chromoting Host installation "
+               << "(error: 0x" << std::hex << hr << std::dec << ").";
+    done_callback.Run(HResultToAsyncResult(hr));
+  }
+}
+
 void DaemonControllerWin::DoSetConfigAndStart(
     scoped_ptr<base::DictionaryValue> config,
     const CompletionCallback& done_callback) {
   IDaemonControl* control = NULL;
   HRESULT hr = worker_thread_.ActivateElevatedController(&control);
   if (FAILED(hr)) {
     done_callback.Run(HResultToAsyncResult(hr));
     return;
   }
 
   // Store the configuration.
   std::string file_content;
   base::JSONWriter::Write(config.get(), &file_content);
 
-  BSTR host_config = ::SysAllocString(UTF8ToUTF16(file_content).c_str());
+  ScopedBstr host_config(UTF8ToUTF16(file_content).c_str());
   if (host_config == NULL) {
     done_callback.Run(HResultToAsyncResult(E_OUTOFMEMORY));
     return;
   }
 
   hr = control->SetConfig(host_config);
-  ::SysFreeString(host_config);
   if (FAILED(hr)) {
     done_callback.Run(HResultToAsyncResult(hr));
     return;
   }
 
   // Start daemon.
   hr = control->StartDaemon();
   done_callback.Run(HResultToAsyncResult(hr));
 }
 
 void DaemonControllerWin::DoStop(const CompletionCallback& done_callback) {
   IDaemonControl* control = NULL;
   HRESULT hr = worker_thread_.ActivateElevatedController(&control);
   if (FAILED(hr)) {
     done_callback.Run(HResultToAsyncResult(hr));
     return;
   }
 
   hr = control->StopDaemon();
   done_callback.Run(HResultToAsyncResult(hr));
 }
 
 }  // namespace
 
 scoped_ptr<DaemonController> remoting::DaemonController::Create() {
   return scoped_ptr<DaemonController>(new DaemonControllerWin());
 }
 
 }  // namespace remoting