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/mac/dispatch_source_mach.h"
  14 #include "base/mac/scoped_mach_port.h"
  15 #include "base/memory/scoped_ptr.h"
  16 #include "base/memory/singleton.h"
  17 #include "base/process/process_handle.h"
  18 #include "base/process/process_metrics.h"
  19 #include "base/synchronization/lock.h"
  20 #include "content/public/browser/browser_child_process_observer.h"
  21 #include "content/public/browser/notification_observer.h"
  22 #include "content/public/browser/notification_registrar.h"
  23
  24 namespace content {
  25
  26 // On OS X, the mach_port_t of a process is required to collect metrics about
  27 // the process. Running |task_for_pid()| is only allowed for privileged code.
  28 // However, a process has port rights to all its subprocesses, so let the
  29 // browser's child processes send their Mach port to the browser over IPC.
  30 // This way, the brower can at least collect metrics of its child processes,
  31 // which is what it's most interested in anyway.
  32 //
  33 // Mach ports can only be sent over Mach IPC, not over the |socketpair()| that
  34 // the regular IPC system uses. Hence, the child processes open a Mach
  35 // connection shortly after launching and ipc their mach data to the browser
  36 // process. This data is kept in a global |MachBroker| object.
  37 //
  38 // Since this data arrives over a separate channel, it is not available
  39 // immediately after a child process has been started.
  40 class CONTENT_EXPORT MachBroker : public base::ProcessMetrics::PortProvider,
  41                                   public BrowserChildProcessObserver,
  42                                   public NotificationObserver {
  43  public:
  44   // For use in child processes. This will send the task port of the current
  45   // process over Mach IPC to the port registered by name (via this class) in
  46   // the parent process. Returns true if the message was sent successfully
  47   // and false if otherwise.
  48   static bool ChildSendTaskPortToParent();
  49
  50   // Returns the global MachBroker.
  51   static MachBroker* GetInstance();
  52
  53   // The lock that protects this MachBroker object.  Clients MUST acquire and
  54   // release this lock around calls to EnsureRunning(), PlaceholderForPid(),
  55   // and FinalizePid().
  56   base::Lock& GetLock();
  57
  58   // Performs any necessary setup that cannot happen in the constructor.
  59   // Callers MUST acquire the lock given by GetLock() before calling this
  60   // method (and release the lock afterwards).
  61   void EnsureRunning();
  62
  63   // Adds a placeholder to the map for the given pid with MACH_PORT_NULL.
  64   // Callers are expected to later update the port with FinalizePid().  Callers
  65   // MUST acquire the lock given by GetLock() before calling this method (and
  66   // release the lock afterwards).
  67   void AddPlaceholderForPid(base::ProcessHandle pid, int child_process_id);
  68
  69   // Implement |ProcessMetrics::PortProvider|.
  70   mach_port_t TaskForPid(base::ProcessHandle process) const override;
  71
  72   // Implement |BrowserChildProcessObserver|.
  73   void BrowserChildProcessHostDisconnected(
  74       const ChildProcessData& data) override;
  75   void BrowserChildProcessCrashed(const ChildProcessData& data,
  76       int exit_code) override;
  77
  78   // Implement |NotificationObserver|.
  79   void Observe(int type,
  80                const NotificationSource& source,
  81                const NotificationDetails& details) override;
  82
  83   // Returns the Mach port name to use when sending or receiving messages.
  84   // Does the Right Thing in the browser and in child processes.
  85   static std::string GetMachPortName();
  86
  87  private:
  88   friend class MachBrokerTest;
  89   friend struct base::DefaultSingletonTraits<MachBroker>;
  90
  91   MachBroker();
  92   ~MachBroker() override;
  93
  94   // Performs any initialization work.
  95   bool Init();
  96
  97   // Message handler that is invoked on |dispatch_source_| when an
  98   // incoming message needs to be received.
  99   void HandleRequest();
 100
 101   // Updates the mapping for |pid| to include the given |mach_info|.  Does
 102   // nothing if PlaceholderForPid() has not already been called for the given
 103   // |pid|.  Callers MUST acquire the lock given by GetLock() before calling
 104   // this method (and release the lock afterwards).
 105   void FinalizePid(base::ProcessHandle pid, mach_port_t task_port);
 106
 107   // Removes all mappings belonging to |child_process_id| from the broker.
 108   void InvalidateChildProcessId(int child_process_id);
 109
 110   // Callback used to register notifications on the UI thread.
 111   void RegisterNotifications();
 112
 113   // Whether or not the class has been initialized.
 114   bool initialized_;
 115
 116   // Used to register for notifications received by NotificationObserver.
 117   // Accessed only on the UI thread.
 118   NotificationRegistrar registrar_;
 119
 120   // The Mach port on which the server listens.
 121   base::mac::ScopedMachReceiveRight server_port_;
 122
 123   // The dispatch source and queue on which Mach messages will be received.
 124   scoped_ptr<base::DispatchSourceMach> dispatch_source_;
 125
 126   // Stores mach info for every process in the broker.
 127   typedef std::map<base::ProcessHandle, mach_port_t> MachMap;
 128   MachMap mach_map_;
 129
 130   // Stores the Child process unique id (RenderProcessHost ID) for every
 131   // process.
 132   typedef std::map<int, base::ProcessHandle> ChildProcessIdMap;
 133   ChildProcessIdMap child_process_id_map_;
 134
 135   // Mutex that guards |mach_map_| and |child_process_id_map_|.
 136   mutable base::Lock lock_;
 137
 138   DISALLOW_COPY_AND_ASSIGN(MachBroker);
 139 };
 140
 141 }  // namespace content
 142
 143 #endif  // CONTENT_BROWSER_MACH_BROKER_MAC_H_