1 // Copyright 2015 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_PROCESS_PORT_PROVIDER_MAC_H_
6 #define BASE_PROCESS_PORT_PROVIDER_MAC_H_
7 
8 #include <mach/mach.h>
9 
10 #include "base/base_export.h"
11 #include "base/macros.h"
12 #include "base/observer_list.h"
13 #include "base/process/process_handle.h"
14 #include "base/synchronization/lock.h"
15 
16 namespace base {
17 
18 // Abstract base class that provides a mapping from ProcessHandle (pid_t) to the
19 // Mach task port. This replicates task_for_pid(), which requires root
20 // privileges.
21 class BASE_EXPORT PortProvider {
22  public:
23   PortProvider();
24   virtual ~PortProvider();
25 
26   class Observer {
27    public:
~Observer()28     virtual ~Observer() {};
29     // Called by the PortProvider to notify observers that the task port was
30     // received for a given process.
31     // No guarantees are made about the thread on which this notification will
32     // be sent.
33     // Observers must not call AddObserver() or RemoveObserver() in this
34     // callback, as doing so will deadlock.
35     virtual void OnReceivedTaskPort(ProcessHandle process) = 0;
36   };
37 
38   // Returns the mach task port for |process| if possible, or else
39   // |MACH_PORT_NULL|.
40   virtual mach_port_t TaskForPid(ProcessHandle process) const = 0;
41 
42   // Observer interface.
43   void AddObserver(Observer* observer);
44   void RemoveObserver(Observer* observer);
45 
46  protected:
47   // Called by subclasses to send a notification to observers.
48   void NotifyObservers(ProcessHandle process);
49 
50  private:
51   // ObserverList is not thread-safe, so |lock_| ensures consistency of
52   // |observer_list_|.
53   base::Lock lock_;
54   base::ObserverList<Observer> observer_list_;
55 
56   DISALLOW_COPY_AND_ASSIGN(PortProvider);
57 };
58 
59 }  // namespace base
60 
61 #endif  // BASE_PROCESS_PORT_PROVIDER_MAC_H_
62