1 // Copyright (c) 2011 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_MACH_BROKER_H_ 6 #define CHROME_BROWSER_MACH_BROKER_H_ 7 #pragma once 8 9 #include <map> 10 #include <string> 11 12 #include <mach/mach.h> 13 14 #include "base/memory/singleton.h" 15 #include "base/process.h" 16 #include "base/process_util.h" 17 #include "base/synchronization/lock.h" 18 #include "content/common/notification_observer.h" 19 #include "content/common/notification_registrar.h" 20 21 // On OS X, the mach_port_t of a process is required to collect metrics about 22 // the process. Running |task_for_pid()| is only allowed for privileged code. 23 // However, a process has port rights to all its subprocesses, so let the 24 // browser's child processes send their Mach port to the browser over IPC. 25 // This way, the brower can at least collect metrics of its child processes, 26 // which is what it's most interested in anyway. 27 // 28 // Mach ports can only be sent over Mach IPC, not over the |socketpair()| that 29 // the regular IPC system uses. Hence, the child processes open a Mach 30 // connection shortly after launching and ipc their mach data to the browser 31 // process. This data is kept in a global |MachBroker| object. 32 // 33 // Since this data arrives over a separate channel, it is not available 34 // immediately after a child process has been started. 35 class MachBroker : public base::ProcessMetrics::PortProvider, 36 public NotificationObserver { 37 public: 38 // Returns the global MachBroker. 39 static MachBroker* GetInstance(); 40 41 // Performs any necessary setup that cannot happen in the constructor. 42 // Clients MUST call this method before fork()ing any children. 43 void PrepareForFork(); 44 45 struct MachInfo { MachInfoMachInfo46 MachInfo() : mach_task_(MACH_PORT_NULL) {} 47 SetTaskMachInfo48 MachInfo& SetTask(mach_port_t task) { 49 mach_task_ = task; 50 return *this; 51 } 52 53 mach_port_t mach_task_; 54 }; 55 56 // Adds a placeholder to the map for the given pid with MACH_PORT_NULL. 57 // Callers are expected to later update the port with FinalizePid(). Callers 58 // MUST acquire the lock given by GetLock() before calling this method (and 59 // release the lock afterwards). 60 void AddPlaceholderForPid(base::ProcessHandle pid); 61 62 // Updates the mapping for |pid| to include the given |mach_info|. Does 63 // nothing if PlaceholderForPid() has not already been called for the given 64 // |pid|. Callers MUST acquire the lock given by GetLock() before calling 65 // this method (and release the lock afterwards). 66 void FinalizePid(base::ProcessHandle pid, const MachInfo& mach_info); 67 68 // Removes all mappings belonging to |pid| from the broker. 69 void InvalidatePid(base::ProcessHandle pid); 70 71 // The lock that protects this MachBroker object. Clients MUST acquire and 72 // release this lock around calls to PlaceholderForPid() and FinalizePid(). 73 base::Lock& GetLock(); 74 75 // Returns the Mach port name to use when sending or receiving messages. 76 // Does the Right Thing in the browser and in child processes. 77 static std::string GetMachPortName(); 78 79 // Implement |ProcessMetrics::PortProvider|. 80 virtual mach_port_t TaskForPid(base::ProcessHandle process) const; 81 82 // Implement |NotificationObserver|. 83 virtual void Observe(NotificationType type, 84 const NotificationSource& source, 85 const NotificationDetails& details); 86 private: 87 // Private constructor. 88 MachBroker(); 89 ~MachBroker(); 90 91 // True if the listener thread has been started. 92 bool listener_thread_started_; 93 94 // Used to register for notifications received by NotificationObserver. 95 // Accessed only on the UI thread. 96 NotificationRegistrar registrar_; 97 98 // Stores mach info for every process in the broker. 99 typedef std::map<base::ProcessHandle, MachInfo> MachMap; 100 MachMap mach_map_; 101 102 // Mutex that guards |mach_map_|. 103 mutable base::Lock lock_; 104 105 friend class MachBrokerTest; 106 friend class RegisterNotificationTask; 107 // Needed in order to make the constructor private. 108 friend struct DefaultSingletonTraits<MachBroker>; 109 DISALLOW_COPY_AND_ASSIGN(MachBroker); 110 }; 111 112 #endif // CHROME_BROWSER_MACH_BROKER_H_ 113 114