remoting/host/win/worker_process_launcher.h

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef REMOTING_HOST_WIN_WORKER_PROCESS_LAUNCHER_H_
   6 #define REMOTING_HOST_WIN_WORKER_PROCESS_LAUNCHER_H_
   7
   8 #include "base/basictypes.h"
   9 #include "base/callback.h"
  10 #include "base/compiler_specific.h"
  11 #include "base/memory/ref_counted.h"
  12 #include "base/memory/scoped_ptr.h"
  13 #include "base/threading/non_thread_safe.h"
  14 #include "base/timer/timer.h"
  15 #include "base/win/object_watcher.h"
  16 #include "base/win/scoped_handle.h"
  17 #include "net/base/backoff_entry.h"
  18
  19 namespace base {
  20 class SingleThreadTaskRunner;
  21 class TimeDelta;
  22 } // namespace base
  23
  24 namespace IPC {
  25 class Message;
  26 } // namespace IPC
  27
  28 namespace tracked_objects {
  29 class Location;
  30 }  // namespace tracked_objects
  31
  32 namespace remoting {
  33
  34 class WorkerProcessIpcDelegate;
  35
  36 // Launches a worker process that is controlled via an IPC channel. All
  37 // interaction with the spawned process is through WorkerProcessIpcDelegate and
  38 // Send() method. In case of error the channel is closed and the worker process
  39 // is terminated.
  40 class WorkerProcessLauncher
  41     : public base::NonThreadSafe,
  42       public base::win::ObjectWatcher::Delegate {
  43  public:
  44   class Delegate {
  45    public:
  46     virtual ~Delegate();
  47
  48     // Asynchronously starts the worker process and creates an IPC channel it
  49     // can connect to. |event_handler| must remain valid until KillProcess() has
  50     // been called.
  51     virtual void LaunchProcess(WorkerProcessLauncher* event_handler) = 0;
  52
  53     // Sends an IPC message to the worker process. The message will be silently
  54     // dropped if the channel is closed.
  55     virtual void Send(IPC::Message* message) = 0;
  56
  57     // Closes the IPC channel.
  58     virtual void CloseChannel() = 0;
  59
  60     // Terminates the worker process and closes the IPC channel.
  61     virtual void KillProcess() = 0;
  62   };
  63
  64   // Creates the launcher that will use |launcher_delegate| to manage the worker
  65   // process and |ipc_handler| to handle IPCs. The caller must ensure that
  66   // |ipc_handler| must outlive this object.
  67   WorkerProcessLauncher(scoped_ptr<Delegate> launcher_delegate,
  68                         WorkerProcessIpcDelegate* ipc_handler);
  69   ~WorkerProcessLauncher() override;
  70
  71   // Asks the worker process to crash and generate a dump, and closes the IPC
  72   // channel. |location| is passed to the worker so that it is on the stack in
  73   // the dump. Restarts the worker process forcefully, if it does
  74   // not exit on its own.
  75   void Crash(const tracked_objects::Location& location);
  76
  77   // Sends an IPC message to the worker process. The message will be silently
  78   // dropped if Send() is called before Start() or after stutdown has been
  79   // initiated.
  80   void Send(IPC::Message* message);
  81
  82   // Notification methods invoked by |Delegate|.
  83
  84   // Invoked to pass a handle of the launched process back to the caller of
  85   // Delegate::LaunchProcess(). The delegate has to make sure that this method
  86   // is called before OnChannelConnected().
  87   void OnProcessLaunched(base::win::ScopedHandle worker_process);
  88
  89   // Called when a fatal error occurs (i.e. a failed process launch).
  90   // The delegate must guarantee that no other notifications are delivered once
  91   // OnFatalError() has been called.
  92   void OnFatalError();
  93
  94   // Mirrors methods of IPC::Listener to be invoked by |Delegate|. |Delegate|
  95   // has to validate |peer_pid| if necessary.
  96   bool OnMessageReceived(const IPC::Message& message);
  97   void OnChannelConnected(int32 peer_pid);
  98   void OnChannelError();
  99
 100  private:
 101   friend class WorkerProcessLauncherTest;
 102
 103   // base::win::ObjectWatcher::Delegate implementation used to watch for
 104   // the worker process exiting.
 105   void OnObjectSignaled(HANDLE object) override;
 106
 107   // Returns true when the object is being destroyed.
 108   bool stopping() const { return ipc_handler_ == nullptr; }
 109
 110   // Attempts to launch the worker process. Schedules next launch attempt if
 111   // creation of the process fails.
 112   void LaunchWorker();
 113
 114   // Called to record outcome of a launch attempt: success or failure.
 115   void RecordLaunchResult();
 116
 117   // Called by the test to record a successful launch attempt.
 118   void RecordSuccessfulLaunchForTest();
 119
 120   // Set the desired timeout for |kill_process_timer_|.
 121   void SetKillProcessTimeoutForTest(const base::TimeDelta& timeout);
 122
 123   // Stops the worker process and schedules next launch attempt unless the
 124   // object is being destroyed already.
 125   void StopWorker();
 126
 127   // Handles IPC messages sent by the worker process.
 128   WorkerProcessIpcDelegate* ipc_handler_;
 129
 130   // Implements specifics of launching a worker process.
 131   scoped_ptr<WorkerProcessLauncher::Delegate> launcher_delegate_;
 132
 133   // Keeps the exit code of the worker process after it was closed. The exit
 134   // code is used to determine whether the process has to be restarted.
 135   DWORD exit_code_;
 136
 137   // True if IPC messages should be passed to |ipc_handler_|.
 138   bool ipc_enabled_;
 139
 140   // The timer used to delay termination of the worker process when an IPC error
 141   // occured or when Crash() request is pending
 142   base::OneShotTimer<WorkerProcessLauncher> kill_process_timer_;
 143
 144   // The default timeout for |kill_process_timer_|.
 145   base::TimeDelta kill_process_timeout_;
 146
 147   // State used to backoff worker launch attempts on failure.
 148   net::BackoffEntry launch_backoff_;
 149
 150   // Timer used to schedule the next attempt to launch the process.
 151   base::OneShotTimer<WorkerProcessLauncher> launch_timer_;
 152
 153   // Monitors |worker_process_| to detect when the launched process
 154   // terminates.
 155   base::win::ObjectWatcher process_watcher_;
 156
 157   // Timer used to detect whether a launch attempt was successful or not, and to
 158   // cancel the launch attempt if it is taking too long.
 159   base::OneShotTimer<WorkerProcessLauncher> launch_result_timer_;
 160
 161   // The handle of the worker process, if launched.
 162   base::win::ScopedHandle worker_process_;
 163
 164   DISALLOW_COPY_AND_ASSIGN(WorkerProcessLauncher);
 165 };
 166
 167 }  // namespace remoting
 168
 169 #endif  // REMOTING_HOST_WIN_WORKER_PROCESS_LAUNCHER_H_