1 // Copyright 2016 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 BASE_MAC_MACH_PORT_BROKER_H_ 6 #define BASE_MAC_MACH_PORT_BROKER_H_ 7 8 #include <mach/mach.h> 9 10 #include <map> 11 #include <memory> 12 #include <string> 13 14 #include "base/base_export.h" 15 #include "base/mac/dispatch_source_mach.h" 16 #include "base/mac/scoped_mach_port.h" 17 #include "base/macros.h" 18 #include "base/process/port_provider_mac.h" 19 #include "base/process/process_handle.h" 20 #include "base/synchronization/lock.h" 21 22 namespace base { 23 24 // On OS X, the task port of a process is required to collect metrics about the 25 // process, and to insert Mach ports into the process. Running |task_for_pid()| 26 // is only allowed for privileged code. However, a process has port rights to 27 // all its subprocesses, so let the child processes send their Mach port to the 28 // parent over IPC. 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 opens a Mach 32 // connection shortly after launching and ipc their mach data to the parent 33 // process. A single |MachPortBroker| with a given name is expected to exist in 34 // the parent process. 35 // 36 // Since this data arrives over a separate channel, it is not available 37 // immediately after a child process has been started. 38 class BASE_EXPORT MachPortBroker : public base::PortProvider { 39 public: 40 // For use in child processes. This will send the task port of the current 41 // process over Mach IPC to the port registered by name (via this class) in 42 // the parent process. Returns true if the message was sent successfully 43 // and false if otherwise. 44 static bool ChildSendTaskPortToParent(const std::string& name); 45 46 // Returns the Mach port name to use when sending or receiving messages. 47 // Does the Right Thing in the browser and in child processes. 48 static std::string GetMachPortName(const std::string& name, bool is_child); 49 50 MachPortBroker(const std::string& name); 51 ~MachPortBroker() override; 52 53 // Performs any initialization work. 54 bool Init(); 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 // Removes |pid| from the task port map. Callers MUST acquire the lock given 63 // by GetLock() before calling this method (and release the lock afterwards). 64 void InvalidatePid(base::ProcessHandle pid); 65 66 // The lock that protects this MachPortBroker object. Callers MUST acquire 67 // and release this lock around calls to AddPlaceholderForPid(), 68 // InvalidatePid(), and FinalizePid(); GetLock()69 base::Lock& GetLock() { return lock_; } 70 71 // Implement |base::PortProvider|. 72 mach_port_t TaskForPid(base::ProcessHandle process) const override; 73 74 private: 75 friend class MachPortBrokerTest; 76 77 // Message handler that is invoked on |dispatch_source_| when an 78 // incoming message needs to be received. 79 void HandleRequest(); 80 81 // Updates the mapping for |pid| to include the given |mach_info|. Does 82 // nothing if PlaceholderForPid() has not already been called for the given 83 // |pid|. Callers MUST acquire the lock given by GetLock() before calling 84 // this method (and release the lock afterwards). 85 void FinalizePid(base::ProcessHandle pid, mach_port_t task_port); 86 87 // Name used to identify a particular port broker. 88 const std::string name_; 89 90 // The Mach port on which the server listens. 91 base::mac::ScopedMachReceiveRight server_port_; 92 93 // The dispatch source and queue on which Mach messages will be received. 94 std::unique_ptr<base::DispatchSourceMach> dispatch_source_; 95 96 // Stores mach info for every process in the broker. 97 typedef std::map<base::ProcessHandle, mach_port_t> MachMap; 98 MachMap mach_map_; 99 100 // Mutex that guards |mach_map_|. 101 mutable base::Lock lock_; 102 103 DISALLOW_COPY_AND_ASSIGN(MachPortBroker); 104 }; 105 106 } // namespace base 107 108 #endif // BASE_MAC_MACH_PORT_BROKER_H_ 109