1 // Copyright 2019 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_CHILD_PROCESS_TASK_PORT_PROVIDER_MAC_H_
6 #define CONTENT_BROWSER_CHILD_PROCESS_TASK_PORT_PROVIDER_MAC_H_
7 
8 #include <map>
9 
10 #include "base/mac/dispatch_source_mach.h"
11 #include "base/mac/scoped_mach_port.h"
12 #include "base/macros.h"
13 #include "base/no_destructor.h"
14 #include "base/process/port_provider_mac.h"
15 #include "base/process/process_handle.h"
16 #include "base/synchronization/lock.h"
17 #include "content/common/child_process.mojom-forward.h"
18 #include "content/common/content_export.h"
19 #include "mojo/public/cpp/platform/platform_handle.h"
20 
21 namespace content {
22 
23 // The ChildProcessTaskPortProvider keeps an association between a PID and the
24 // process's task port. This association is needed for the browser to manipulate
25 // certain aspects of its child processes.
26 class CONTENT_EXPORT ChildProcessTaskPortProvider : public base::PortProvider {
27  public:
28   // Returns the singleton instance.
29   static ChildProcessTaskPortProvider* GetInstance();
30 
31   // Called by BrowserChildProcessHostImpl and RenderProcessHostImpl when
32   // a new child has been created. This will invoke the GetTaskPort() method
33   // on |child_control| and will store the returned port as being associated to
34   // |pid|.
35   //
36   // When the kernel sends a notification that the port has become a dead name,
37   // indicating that the child process has died, the association will be
38   // removed.
39   void OnChildProcessLaunched(base::ProcessHandle pid,
40                               mojom::ChildProcess* child_process);
41 
42   // base::PortProvider:
43   mach_port_t TaskForPid(base::ProcessHandle process) const override;
44 
45  private:
46   friend class ChildProcessTaskPortProviderTest;
47   friend base::NoDestructor<ChildProcessTaskPortProvider>;
48 
49   ChildProcessTaskPortProvider();
50   ~ChildProcessTaskPortProvider() override;
51 
52   // Callback for mojom::ChildProcess::GetTaskPort reply.
53   void OnTaskPortReceived(base::ProcessHandle pid,
54                           mojo::PlatformHandle task_port);
55 
56   // Event handler for |notification_source_|, invoked for
57   // MACH_NOTIFY_DEAD_NAME.
58   void OnTaskPortDied();
59 
60   // Lock that protects the map below.
61   mutable base::Lock lock_;
62 
63   // Maps a PID to the corresponding task port.
64   using PidToTaskPortMap =
65       std::map<base::ProcessHandle, base::mac::ScopedMachSendRight>;
66   PidToTaskPortMap pid_to_task_port_;
67 
68   // A Mach port that is used to register for dead name notifications from
69   // the kernel. All the ports in |pid_to_task_port_| have a notification set
70   // up to send to this port.
71   base::mac::ScopedMachReceiveRight notification_port_;
72 
73   // Dispatch source for |notification_port_|.
74   std::unique_ptr<base::DispatchSourceMach> notification_source_;
75 
76   DISALLOW_COPY_AND_ASSIGN(ChildProcessTaskPortProvider);
77 };
78 
79 }  // namespace content
80 
81 #endif  // CONTENT_BROWSER_CHILD_PROCESS_TASK_PORT_PROVIDER_MAC_H_
82