[Chromoting] Create per-session job objects to control processes launched in a session.

Processes from different sessions cannot be attached to the same job object even in the case when their lifetimes do not overlap. The CL causes |WtsSessionProcessLauncher| to create a new job object every time it is switched to a new session. This CL also makes sure that the host process will be completely shutdown before trying to re-launch it is a different session to avoid the race with the session attach notification.

BUG=149098,153005


Review URL: https://chromiumcodereview.appspot.com/11029004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@159623 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 62 insertions, 44 deletions

diff --git a/remoting/host/win/wts_session_process_launcher.cc b/remoting/host/win/wts_session_process_launcher.cc
index 2073f60..9b991fa 100644
--- a/remoting/host/win/wts_session_process_launcher.cc
+++ b/remoting/host/win/wts_session_process_launcher.cc
@@ -74,9 +74,6 @@ class WtsSessionProcessLauncherImpl
   // Returns the exit code of the worker process.
   virtual DWORD GetExitCode() = 0;
 
-  // Sets the token to be used to launch the worker process.
-  virtual void ResetUserToken(ScopedHandle* user_token) = 0;
-
   // Stops the object asynchronously.
   virtual void Stop() = 0;
 
@@ -93,6 +90,7 @@ namespace {
 class SingleProcessLauncher : public WtsSessionProcessLauncherImpl {
  public:
   SingleProcessLauncher(
+      uint32 session_id,
       const FilePath& binary_path,
       scoped_refptr<base::SingleThreadTaskRunner> main_task_runner);
 
@@ -104,7 +102,6 @@ class SingleProcessLauncher : public WtsSessionProcessLauncherImpl {
 
   // WtsSessionProcessLauncherImpl implementation.
   virtual DWORD GetExitCode() OVERRIDE;
-  virtual void ResetUserToken(ScopedHandle* user_token) OVERRIDE;
   virtual void Stop() OVERRIDE;
 
  private:
@@ -134,6 +131,7 @@ class ElevatedProcessLauncher : public WtsSessionProcessLauncherImpl,
                                 public base::MessagePumpForIO::IOHandler {
  public:
   ElevatedProcessLauncher(
+      uint32 session_id,
       const FilePath& binary_path,
       scoped_refptr<base::SingleThreadTaskRunner> main_task_runner,
       scoped_refptr<base::SingleThreadTaskRunner> io_task_runner);
@@ -151,7 +149,6 @@ class ElevatedProcessLauncher : public WtsSessionProcessLauncherImpl,
 
   // WtsSessionProcessLauncherImpl implementation.
   virtual DWORD GetExitCode() OVERRIDE;
-  virtual void ResetUserToken(ScopedHandle* user_token) OVERRIDE;
   virtual void Stop() OVERRIDE;
 
  private:
@@ -197,10 +194,12 @@ class ElevatedProcessLauncher : public WtsSessionProcessLauncherImpl,
 };
 
 SingleProcessLauncher::SingleProcessLauncher(
+    uint32 session_id,
     const FilePath& binary_path,
     scoped_refptr<base::SingleThreadTaskRunner> main_task_runner)
     : binary_path_(binary_path),
       main_task_runner_(main_task_runner) {
+  CHECK(CreateSessionToken(session_id, &user_token_));
 }
 
 bool SingleProcessLauncher::DoLaunchProcess(
@@ -272,17 +271,12 @@ DWORD SingleProcessLauncher::GetExitCode() {
   return exit_code;
 }
 
-void SingleProcessLauncher::ResetUserToken(ScopedHandle* user_token) {
-  DCHECK(main_task_runner_->BelongsToCurrentThread());
-
-  user_token_ = user_token->Pass();
-}
-
 void SingleProcessLauncher::Stop() {
   DCHECK(main_task_runner_->BelongsToCurrentThread());
 }
 
 ElevatedProcessLauncher::ElevatedProcessLauncher(
+    uint32 session_id,
     const FilePath& binary_path,
     scoped_refptr<base::SingleThreadTaskRunner> main_task_runner,
     scoped_refptr<base::SingleThreadTaskRunner> io_task_runner)
@@ -292,6 +286,8 @@ ElevatedProcessLauncher::ElevatedProcessLauncher(
   process_exit_event_.Set(CreateEvent(NULL, TRUE, FALSE, NULL));
   CHECK(process_exit_event_.IsValid());
 
+  CHECK(CreateSessionToken(session_id, &user_token_));
+
   // To receive job object notifications the job object is registered with
   // the completion port represented by |io_task_runner|. The registration has
   // to be done on the I/O thread because MessageLoopForIO::RegisterJobObject()
@@ -411,13 +407,6 @@ DWORD ElevatedProcessLauncher::GetExitCode() {
   return exit_code;
 }
 
-void ElevatedProcessLauncher::ResetUserToken(
-    ScopedHandle* user_token) {
-  DCHECK(main_task_runner_->BelongsToCurrentThread());
-
-  user_token_ = user_token->Pass();
-}
-
 void ElevatedProcessLauncher::Stop() {
   DCHECK(main_task_runner_->BelongsToCurrentThread());
 
@@ -543,25 +532,7 @@ WtsSessionProcessLauncher::WtsSessionProcessLauncher(
     Stop();
     return;
   }
-  FilePath host_binary = dir_path.Append(kMe2meHostBinaryName);
-
-  // The workaround we use to launch a process in a not yet logged in session
-  // (see CreateRemoteSessionProcess()) on Windows XP/2K3 does not let us to
-  // assign the started process to a job. However on Vista+ we have to start
-  // the host via a helper process. The helper process calls ShellExecute() that
-  // does not work across the session boundary but it required to launch
-  // a binary specifying uiAccess='true' in its manifest.
-  //
-  // Below we choose which implementation of |WorkerProcessLauncher::Delegate|
-  // to use. A single process is launched on XP (since uiAccess='true' does not
-  // have effect any way). Vista+ utilizes a helper process and assign it to
-  // a job object to control it.
-  if (base::win::GetVersion() == base::win::VERSION_XP) {
-    impl_ = new SingleProcessLauncher(host_binary, main_message_loop);
-  } else {
-    impl_ = new ElevatedProcessLauncher(host_binary, main_message_loop,
-                                        ipc_message_loop);
-  }
+  host_binary_ = dir_path.Append(kMe2meHostBinaryName);
 }
 
 WtsSessionProcessLauncher::~WtsSessionProcessLauncher() {
@@ -598,10 +569,34 @@ void WtsSessionProcessLauncher::OnSessionAttached(uint32 session_id) {
 
   attached_ = true;
 
-  // Create a session token and launch the host.
-  ScopedHandle user_token;
-  if (CreateSessionToken(session_id, &user_token)) {
-    impl_->ResetUserToken(&user_token);
+  // Reset the backoff timeout every time the session is switched.
+  launch_backoff_ = base::TimeDelta();
+
+  // The workaround we use to launch a process in a not yet logged in session
+  // (see CreateRemoteSessionProcess()) on Windows XP/2K3 does not let us to
+  // assign the started process to a job. However on Vista+ we have to start
+  // the host via a helper process. The helper process calls ShellExecute() that
+  // does not work across the session boundary but it required to launch
+  // a binary specifying uiAccess='true' in its manifest.
+  //
+  // Below we choose which implementation of |WorkerProcessLauncher::Delegate|
+  // to use. A single process is launched on XP (since uiAccess='true' does not
+  // have effect any way). Vista+ utilizes a helper process and assign it to
+  // a job object to control it.
+  if (new_impl_.get()) {
+    new_impl_->Stop();
+    new_impl_ = NULL;
+  }
+  if (base::win::GetVersion() == base::win::VERSION_XP) {
+    new_impl_ = new SingleProcessLauncher(session_id, host_binary_,
+                                          main_message_loop_);
+  } else {
+    new_impl_ = new ElevatedProcessLauncher(session_id, host_binary_,
+                                            main_message_loop_,
+                                            ipc_message_loop_);
+  }
+
+  if (launcher_.get() == NULL) {
     LaunchProcess();
   }
 }
@@ -631,7 +626,11 @@ void WtsSessionProcessLauncher::DoStop() {
     return;
   }
 
-  // Tear down the core asynchromously.
+  // Tear down implementation objects asynchromously.
+  if (new_impl_.get()) {
+    new_impl_->Stop();
+    new_impl_ = NULL;
+  }
   if (impl_.get()) {
     impl_->Stop();
     impl_ = NULL;
@@ -646,6 +645,18 @@ void WtsSessionProcessLauncher::LaunchProcess() {
   DCHECK(launcher_.get() == NULL);
   DCHECK(!timer_.IsRunning());
 
+  // Switch to a new implementation object if needed.
+  if (new_impl_.get() != NULL) {
+    if (impl_.get() != NULL) {
+      impl_->Stop();
+      impl_ = NULL;
+    }
+
+    impl_.swap(new_impl_);
+  }
+
+  DCHECK(impl_.get() != NULL);
+
   launch_time_ = base::Time::Now();
   launcher_.reset(new WorkerProcessLauncher(
       impl_.get(), this,
diff --git a/remoting/host/win/wts_session_process_launcher.h b/remoting/host/win/wts_session_process_launcher.h
index 040a4f3..e9a8e54 100644
--- a/remoting/host/win/wts_session_process_launcher.h
+++ b/remoting/host/win/wts_session_process_launcher.h
@@ -74,10 +74,17 @@ class WtsSessionProcessLauncher
   // |true| if this object is currently attached to the console session.
   bool attached_;
 
-  // The specific code knowing how to launch and control a child process
-  // implemented by |WtsSessionProcessLauncherImpl|.
+  // Path to the host binary to launch.
+  FilePath host_binary_;
+
+  // OS version dependent WorkerProcessLauncher::Delegate implementation
+  // instance for the currently-running child process.
   scoped_refptr<WtsSessionProcessLauncherImpl> impl_;
 
+  // WorkerProcessLauncher::Delegate implementation that will be used to launch
+  // the new child process after a session switch.
+  scoped_refptr<WtsSessionProcessLauncherImpl> new_impl_;
+
   // Time of the last launch attempt.
   base::Time launch_time_;