content/browser/mach_broker_mac.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 CONTENT_BROWSER_MACH_BROKER_MAC_H_
   6 #define CONTENT_BROWSER_MACH_BROKER_MAC_H_
   7
   8 #include <mach/mach.h>
   9
  10 #include <map>
  11 #include <string>
  12
  13 #include "base/memory/singleton.h"
  14 #include "base/process/process_handle.h"
  15 #include "base/process/process_metrics.h"
  16 #include "base/synchronization/lock.h"
  17 #include "content/public/browser/browser_child_process_observer.h"
  18 #include "content/public/browser/notification_observer.h"
  19 #include "content/public/browser/notification_registrar.h"
  20
  21 namespace content {
  22
  23 // On OS X, the mach_port_t of a process is required to collect metrics about
  24 // the process. Running |task_for_pid()| is only allowed for privileged code.
  25 // However, a process has port rights to all its subprocesses, so let the
  26 // browser's child processes send their Mach port to the browser over IPC.
  27 // This way, the brower can at least collect metrics of its child processes,
  28 // which is what it's most interested in anyway.
  29 //
  30 // Mach ports can only be sent over Mach IPC, not over the |socketpair()| that
  31 // the regular IPC system uses. Hence, the child processes open a Mach
  32 // connection shortly after launching and ipc their mach data to the browser
  33 // process. This data is kept in a global |MachBroker| object.
  34 //
  35 // Since this data arrives over a separate channel, it is not available
  36 // immediately after a child process has been started.
  37 class CONTENT_EXPORT MachBroker : public base::ProcessMetrics::PortProvider,
  38                                   public BrowserChildProcessObserver,
  39                                   public NotificationObserver {
  40  public:
  41   // For use in child processes. This will send the task port of the current
  42   // process over Mach IPC to the port registered by name (via this class) in
  43   // the parent process. Returns true if the message was sent successfully
  44   // and false if otherwise.
  45   static bool ChildSendTaskPortToParent();
  46
  47   // Returns the global MachBroker.
  48   static MachBroker* GetInstance();
  49
  50   // The lock that protects this MachBroker object.  Clients MUST acquire and
  51   // release this lock around calls to EnsureRunning(), PlaceholderForPid(),
  52   // and FinalizePid().
  53   base::Lock& GetLock();
  54
  55   // Performs any necessary setup that cannot happen in the constructor.
  56   // Callers MUST acquire the lock given by GetLock() before calling this
  57   // method (and release the lock afterwards).
  58   void EnsureRunning();
  59
  60   // Adds a placeholder to the map for the given pid with MACH_PORT_NULL.
  61   // Callers are expected to later update the port with FinalizePid().  Callers
  62   // MUST acquire the lock given by GetLock() before calling this method (and
  63   // release the lock afterwards).
  64   void AddPlaceholderForPid(base::ProcessHandle pid, int child_process_id);
  65
  66   // Implement |ProcessMetrics::PortProvider|.
  67   mach_port_t TaskForPid(base::ProcessHandle process) const override;
  68
  69   // Implement |BrowserChildProcessObserver|.
  70   void BrowserChildProcessHostDisconnected(
  71       const ChildProcessData& data) override;
  72   void BrowserChildProcessCrashed(const ChildProcessData& data,
  73       int exit_code) override;
  74
  75   // Implement |NotificationObserver|.
  76   void Observe(int type,
  77                const NotificationSource& source,
  78                const NotificationDetails& details) override;
  79
  80  private:
  81   friend class MachBrokerTest;
  82   friend class MachListenerThreadDelegate;
  83   friend struct DefaultSingletonTraits<MachBroker>;
  84
  85   MachBroker();
  86   ~MachBroker() override;
  87
  88   // Updates the mapping for |pid| to include the given |mach_info|.  Does
  89   // nothing if PlaceholderForPid() has not already been called for the given
  90   // |pid|.  Callers MUST acquire the lock given by GetLock() before calling
  91   // this method (and release the lock afterwards).
  92   void FinalizePid(base::ProcessHandle pid, mach_port_t task_port);
  93
  94   // Removes all mappings belonging to |child_process_id| from the broker.
  95   void InvalidateChildProcessId(int child_process_id);
  96
  97   // Returns the Mach port name to use when sending or receiving messages.
  98   // Does the Right Thing in the browser and in child processes.
  99   static std::string GetMachPortName();
 100   // Callback used to register notifications on the UI thread.
 101   void RegisterNotifications();
 102
 103   // True if the listener thread has been started.
 104   bool listener_thread_started_;
 105
 106   // Used to register for notifications received by NotificationObserver.
 107   // Accessed only on the UI thread.
 108   NotificationRegistrar registrar_;
 109
 110   // Stores mach info for every process in the broker.
 111   typedef std::map<base::ProcessHandle, mach_port_t> MachMap;
 112   MachMap mach_map_;
 113
 114   // Stores the Child process unique id (RenderProcessHost ID) for every
 115   // process.
 116   typedef std::map<int, base::ProcessHandle> ChildProcessIdMap;
 117   ChildProcessIdMap child_process_id_map_;
 118
 119   // Mutex that guards |mach_map_| and |child_process_id_map_|.
 120   mutable base::Lock lock_;
 121
 122   DISALLOW_COPY_AND_ASSIGN(MachBroker);
 123 };
 124
 125 }  // namespace content
 126
 127 #endif  // CONTENT_BROWSER_MACH_BROKER_MAC_H_