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