chrome/browser/process_singleton.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 CHROME_BROWSER_PROCESS_SINGLETON_H_
   6 #define CHROME_BROWSER_PROCESS_SINGLETON_H_
   7
   8 #include "build/build_config.h"
   9
  10 #if defined(OS_WIN)
  11 #include <windows.h>
  12 #endif  // defined(OS_WIN)
  13
  14 #include <set>
  15 #include <vector>
  16
  17 #include "base/basictypes.h"
  18 #include "base/callback.h"
  19 #include "base/command_line.h"
  20 #include "base/files/file_path.h"
  21 #include "base/logging.h"
  22 #include "base/memory/ref_counted.h"
  23 #include "base/process.h"
  24 #include "base/threading/non_thread_safe.h"
  25 #include "ui/gfx/native_widget_types.h"
  26
  27 #if defined(OS_LINUX) || defined(OS_OPENBSD)
  28 #include "base/files/scoped_temp_dir.h"
  29 #endif  // defined(OS_LINUX) || defined(OS_OPENBSD)
  30
  31 class CommandLine;
  32
  33 // ProcessSingleton ----------------------------------------------------------
  34 //
  35 // This class allows different browser processes to communicate with
  36 // each other.  It is named according to the user data directory, so
  37 // we can be sure that no more than one copy of the application can be
  38 // running at once with a given data directory.
  39 //
  40 // Implementation notes:
  41 // - the Windows implementation uses an invisible global message window;
  42 // - the Linux implementation uses a Unix domain socket in the user data dir.
  43
  44 class ProcessSingleton : public base::NonThreadSafe {
  45  public:
  46   enum NotifyResult {
  47     PROCESS_NONE,
  48     PROCESS_NOTIFIED,
  49     PROFILE_IN_USE,
  50     LOCK_ERROR,
  51     NUM_NOTIFY_RESULTS,
  52   };
  53
  54   // Implement this callback to handle notifications from other processes. The
  55   // callback will receive the command line and directory with which the other
  56   // Chrome process was launched. Return true if the command line will be
  57   // handled within the current browser instance or false if the remote process
  58   // should handle it (i.e., because the current process is shutting down).
  59   typedef base::Callback<bool(
  60       const CommandLine& command_line,
  61       const base::FilePath& current_directory)> NotificationCallback;
  62
  63   ProcessSingleton(const base::FilePath& user_data_dir,
  64                    const NotificationCallback& notification_callback);
  65   ~ProcessSingleton();
  66
  67   // Notify another process, if available. Otherwise sets ourselves as the
  68   // singleton instance. Returns PROCESS_NONE if we became the singleton
  69   // instance. Callers are guaranteed to either have notified an existing
  70   // process or have grabbed the singleton (unless the profile is locked by an
  71   // unreachable process).
  72   // TODO(brettw): Make the implementation of this method non-platform-specific
  73   // by making Linux re-use the Windows implementation.
  74   NotifyResult NotifyOtherProcessOrCreate();
  75
  76   // Sets ourself up as the singleton instance.  Returns true on success.  If
  77   // false is returned, we are not the singleton instance and the caller must
  78   // exit.
  79   // NOTE: Most callers should generally prefer NotifyOtherProcessOrCreate() to
  80   // this method, only callers for whom failure is prefered to notifying another
  81   // process should call this directly.
  82   bool Create();
  83
  84   // Clear any lock state during shutdown.
  85   void Cleanup();
  86
  87 #if defined(OS_WIN)
  88   LRESULT WndProc(HWND hwnd, UINT message, WPARAM wparam, LPARAM lparam);
  89 #endif
  90
  91 #if defined(OS_LINUX) || defined(OS_OPENBSD)
  92   static void DisablePromptForTesting();
  93 #endif  // defined(OS_LINUX) || defined(OS_OPENBSD)
  94
  95  protected:
  96   // Notify another process, if available.
  97   // Returns true if another process was found and notified, false if we should
  98   // continue with the current process.
  99   // On Windows, Create() has to be called before this.
 100   NotifyResult NotifyOtherProcess();
 101
 102 #if defined(OS_LINUX) || defined(OS_OPENBSD)
 103   // Exposed for testing.  We use a timeout on Linux, and in tests we want
 104   // this timeout to be short.
 105   NotifyResult NotifyOtherProcessWithTimeout(const CommandLine& command_line,
 106                                              int timeout_seconds,
 107                                              bool kill_unresponsive);
 108   NotifyResult NotifyOtherProcessWithTimeoutOrCreate(
 109       const CommandLine& command_line,
 110       int timeout_seconds);
 111   void OverrideCurrentPidForTesting(base::ProcessId pid);
 112   void OverrideKillCallbackForTesting(
 113       const base::Callback<void(int)>& callback);
 114 #endif  // defined(OS_LINUX) || defined(OS_OPENBSD)
 115
 116  private:
 117 #if !defined(OS_MACOSX)
 118   // Timeout for the current browser process to respond. 20 seconds should be
 119   // enough. It's only used in Windows and Linux implementations.
 120   static const int kTimeoutInSeconds = 20;
 121 #endif
 122
 123   NotificationCallback notification_callback_;  // Handler for notifications.
 124
 125 #if defined(OS_WIN)
 126   // This ugly behemoth handles startup commands sent from another process.
 127   LRESULT OnCopyData(HWND hwnd, const COPYDATASTRUCT* cds);
 128
 129   bool EscapeVirtualization(const base::FilePath& user_data_dir);
 130
 131   HWND remote_window_;  // The HWND_MESSAGE of another browser.
 132   HWND window_;  // The HWND_MESSAGE window.
 133   bool is_virtualized_;  // Stuck inside Microsoft Softricity VM environment.
 134   HANDLE lock_file_;
 135   base::FilePath user_data_dir_;
 136 #elif defined(OS_LINUX) || defined(OS_OPENBSD)
 137   // Return true if the given pid is one of our child processes.
 138   // Assumes that the current pid is the root of all pids of the current
 139   // instance.
 140   bool IsSameChromeInstance(pid_t pid);
 141
 142   // Extract the process's pid from a symbol link path and if it is on
 143   // the same host, kill the process, unlink the lock file and return true.
 144   // If the process is part of the same chrome instance, unlink the lock file
 145   // and return true without killing it.
 146   // If the process is on a different host, return false.
 147   bool KillProcessByLockPath();
 148
 149   // Default function to kill a process, overridable by tests.
 150   void KillProcess(int pid);
 151
 152   // Allow overriding for tests.
 153   base::ProcessId current_pid_;
 154
 155   // Function to call when the other process is hung and needs to be killed.
 156   // Allows overriding for tests.
 157   base::Callback<void(int)> kill_callback_;
 158
 159   // Path in file system to the socket.
 160   base::FilePath socket_path_;
 161
 162   // Path in file system to the lock.
 163   base::FilePath lock_path_;
 164
 165   // Path in file system to the cookie file.
 166   base::FilePath cookie_path_;
 167
 168   // Temporary directory to hold the socket.
 169   base::ScopedTempDir socket_dir_;
 170
 171   // Helper class for linux specific messages.  LinuxWatcher is ref counted
 172   // because it posts messages between threads.
 173   class LinuxWatcher;
 174   scoped_refptr<LinuxWatcher> watcher_;
 175 #elif defined(OS_MACOSX)
 176   // Path in file system to the lock.
 177   base::FilePath lock_path_;
 178
 179   // File descriptor associated with the lockfile, valid between
 180   // |Create()| and |Cleanup()|.  Two instances cannot have a lock on
 181   // the same file at the same time.
 182   int lock_fd_;
 183 #endif
 184
 185   DISALLOW_COPY_AND_ASSIGN(ProcessSingleton);
 186 };
 187
 188 #endif  // CHROME_BROWSER_PROCESS_SINGLETON_H_