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
35namespace base {
36class 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
50class 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_
176