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1 // Copyright 2015 The Chromium Authors. All rights reserved. | 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 | 2 // Use of this source code is governed by a BSD-style license that can be |
3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
4 | 4 |
5 #ifndef BASE_MEMORY_SHARED_MEMORY_HANDLE_H_ | 5 #ifndef BASE_MEMORY_SHARED_MEMORY_HANDLE_H_ |
6 #define BASE_MEMORY_SHARED_MEMORY_HANDLE_H_ | 6 #define BASE_MEMORY_SHARED_MEMORY_HANDLE_H_ |
7 | 7 |
8 #include <stddef.h> | 8 #include <stddef.h> |
9 | 9 |
10 #include "build/build_config.h" | 10 #include "build/build_config.h" |
11 | 11 |
12 #if defined(OS_WIN) | 12 #if defined(OS_WIN) |
13 #include <windows.h> | 13 #include <windows.h> |
14 #include "base/process/process_handle.h" | 14 #include "base/process/process_handle.h" |
15 #elif defined(OS_MACOSX) && !defined(OS_IOS) | 15 #elif defined(OS_MACOSX) && !defined(OS_IOS) |
16 #include <mach/mach.h> | 16 #include <mach/mach.h> |
17 #include "base/base_export.h" | 17 #include "base/base_export.h" |
18 #include "base/file_descriptor_posix.h" | |
18 #include "base/macros.h" | 19 #include "base/macros.h" |
19 #include "base/process/process_handle.h" | 20 #include "base/process/process_handle.h" |
20 #elif defined(OS_POSIX) | 21 #elif defined(OS_POSIX) |
21 #include <sys/types.h> | 22 #include <sys/types.h> |
22 #include "base/file_descriptor_posix.h" | 23 #include "base/file_descriptor_posix.h" |
23 #endif | 24 #endif |
24 | 25 |
25 namespace base { | 26 namespace base { |
26 | 27 |
27 // SharedMemoryHandle is a platform specific type which represents | 28 // SharedMemoryHandle is a platform specific type which represents |
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76 // Whether passing this object as a parameter to an IPC message passes | 77 // Whether passing this object as a parameter to an IPC message passes |
77 // ownership of |handle_| to the IPC stack. This is meant to mimic the | 78 // ownership of |handle_| to the IPC stack. This is meant to mimic the |
78 // behavior of the |auto_close| parameter of FileDescriptor. This member only | 79 // behavior of the |auto_close| parameter of FileDescriptor. This member only |
79 // affects attachment-brokered SharedMemoryHandles. | 80 // affects attachment-brokered SharedMemoryHandles. |
80 // Defaults to |false|. | 81 // Defaults to |false|. |
81 bool ownership_passes_to_ipc_; | 82 bool ownership_passes_to_ipc_; |
82 }; | 83 }; |
83 #else | 84 #else |
84 class BASE_EXPORT SharedMemoryHandle { | 85 class BASE_EXPORT SharedMemoryHandle { |
85 public: | 86 public: |
87 enum Type { | |
88 // The SharedMemoryHandle is backed by a POSIX fd. | |
89 POSIX, | |
90 // The SharedMemoryHandle is backed by the Mach primitive "memory object". | |
91 MACH, | |
92 }; | |
93 | |
86 // The default constructor returns an invalid SharedMemoryHandle. | 94 // The default constructor returns an invalid SharedMemoryHandle. |
87 SharedMemoryHandle(); | 95 SharedMemoryHandle(); |
88 | 96 |
97 // Constructs a SharedMemoryHandle backed by the components of a | |
98 // FileDescriptor. The newly created instance has the same ownership semantics | |
99 // as base::FileDescriptor. This typically means that the SharedMemoryHandle | |
100 // takes ownership of the |fd| if |auto_close| is true. Unfortunately, it's | |
101 // common for existing code to make shallow copies of SharedMemoryHandle, and | |
102 // the one that is finally passed into a base::SharedMemory is the one that | |
103 // "consumes" the fd. | |
104 explicit SharedMemoryHandle(const base::FileDescriptor& file_descriptor); | |
105 | |
89 // Makes a Mach-based SharedMemoryHandle of the given size. On error, | 106 // Makes a Mach-based SharedMemoryHandle of the given size. On error, |
90 // subsequent calls to IsValid() return false. | 107 // subsequent calls to IsValid() return false. |
91 explicit SharedMemoryHandle(mach_vm_size_t size); | 108 explicit SharedMemoryHandle(mach_vm_size_t size); |
92 | 109 |
93 // Makes a Mach-based SharedMemoryHandle from |memory_object|, a named entry | 110 // Makes a Mach-based SharedMemoryHandle from |memory_object|, a named entry |
94 // in the task with process id |pid|. The memory region has size |size|. | 111 // in the task with process id |pid|. The memory region has size |size|. |
95 SharedMemoryHandle(mach_port_t memory_object, | 112 SharedMemoryHandle(mach_port_t memory_object, |
96 mach_vm_size_t size, | 113 mach_vm_size_t size, |
97 base::ProcessId pid); | 114 base::ProcessId pid); |
98 | 115 |
99 // Standard copy constructor. The new instance shares the underlying OS | 116 // Standard copy constructor. The new instance shares the underlying OS |
100 // primitives. | 117 // primitives. |
101 SharedMemoryHandle(const SharedMemoryHandle& handle); | 118 SharedMemoryHandle(const SharedMemoryHandle& handle); |
102 | 119 |
103 // Standard assignment operator. The updated instance shares the underlying | 120 // Standard assignment operator. The updated instance shares the underlying |
104 // OS primitives. | 121 // OS primitives. |
105 SharedMemoryHandle& operator=(const SharedMemoryHandle& handle); | 122 SharedMemoryHandle& operator=(const SharedMemoryHandle& handle); |
106 | 123 |
107 // Duplicates the underlying OS resources. | 124 // Duplicates the underlying OS resources. Assumes the SharedMemoryHandle is |
125 // of type Mach. | |
Mark Mentovai
2016/12/09 19:53:52
MACH
lawrencewu
2016/12/09 20:32:12
Done.
| |
108 SharedMemoryHandle Duplicate() const; | 126 SharedMemoryHandle Duplicate() const; |
109 | 127 |
110 // Comparison operators. | 128 // Comparison operators. |
111 bool operator==(const SharedMemoryHandle& handle) const; | 129 bool operator==(const SharedMemoryHandle& handle) const; |
112 bool operator!=(const SharedMemoryHandle& handle) const; | 130 bool operator!=(const SharedMemoryHandle& handle) const; |
113 | 131 |
114 // Whether the underlying OS primitive is valid. Once the SharedMemoryHandle | 132 // Whether the underlying OS primitive is valid. Once the SharedMemoryHandle |
115 // is backed by a valid OS primitive, it becomes immutable. | 133 // is backed by a valid OS primitive, it becomes immutable. |
116 bool IsValid() const; | 134 bool IsValid() const; |
117 | 135 |
118 // Exposed so that the SharedMemoryHandle can be transported between | 136 // Exposed so that the SharedMemoryHandle can be transported between |
119 // processes. | 137 // processes. |
120 mach_port_t GetMemoryObject() const; | 138 mach_port_t GetMemoryObject() const; |
121 | 139 |
122 // Returns false on a failure to determine the size. On success, populates the | 140 // Returns false on a failure to determine the size. On success, populates the |
123 // output variable |size|. Returns 0 if the handle is invalid. | 141 // output variable |size|. |
124 bool GetSize(size_t* size) const; | 142 bool GetSize(size_t* size) const; |
125 | 143 |
126 // The SharedMemoryHandle must be valid. | 144 // The SharedMemoryHandle must be valid. |
127 // Returns whether the SharedMemoryHandle was successfully mapped into memory. | 145 // Returns whether the SharedMemoryHandle was successfully mapped into memory. |
128 // On success, |memory| is an output variable that contains the start of the | 146 // On success, |memory| is an output variable that contains the start of the |
129 // mapped memory. | 147 // mapped memory. |
130 bool MapAt(off_t offset, size_t bytes, void** memory, bool read_only); | 148 bool MapAt(off_t offset, size_t bytes, void** memory, bool read_only); |
131 | 149 |
132 // Closes the underlying OS primitive. | 150 // Closes the underlying OS primitive. |
133 void Close() const; | 151 void Close() const; |
134 | 152 |
135 void SetOwnershipPassesToIPC(bool ownership_passes); | 153 void SetOwnershipPassesToIPC(bool ownership_passes); |
136 bool OwnershipPassesToIPC() const; | 154 bool OwnershipPassesToIPC() const; |
137 | 155 |
138 private: | 156 private: |
157 friend class SharedMemory; | |
158 | |
139 // Shared code between copy constructor and operator=. | 159 // Shared code between copy constructor and operator=. |
140 void CopyRelevantData(const SharedMemoryHandle& handle); | 160 void CopyRelevantData(const SharedMemoryHandle& handle); |
141 | 161 |
142 mach_port_t memory_object_ = MACH_PORT_NULL; | 162 Type type_; |
143 | 163 |
144 // The size of the shared memory region when |type_| is MACH. Only | 164 // Each instance of a SharedMemoryHandle is backed either by a POSIX fd or a |
145 // relevant if |memory_object_| is not |MACH_PORT_NULL|. | 165 // mach port. |type_| determines the backing member. |
146 mach_vm_size_t size_ = 0; | 166 union { |
167 FileDescriptor file_descriptor_; | |
147 | 168 |
148 // The pid of the process in which |memory_object_| is usable. Only | 169 struct { |
149 // relevant if |memory_object_| is not |MACH_PORT_NULL|. | 170 mach_port_t memory_object_; |
150 base::ProcessId pid_ = 0; | |
151 | 171 |
152 // Whether passing this object as a parameter to an IPC message passes | 172 // The size of the shared memory region when |type_| is MACH. Only |
153 // ownership of |memory_object_| to the IPC stack. This is meant to mimic | 173 // relevant if |memory_object_| is not |MACH_PORT_NULL|. |
154 // the behavior of the |auto_close| parameter of FileDescriptor. | 174 mach_vm_size_t size_; |
155 // Defaults to |false|. | 175 |
156 bool ownership_passes_to_ipc_ = false; | 176 // The pid of the process in which |memory_object_| is usable. Only |
177 // relevant if |memory_object_| is not |MACH_PORT_NULL|. | |
178 base::ProcessId pid_; | |
179 | |
180 // Whether passing this object as a parameter to an IPC message passes | |
181 // ownership of |memory_object_| to the IPC stack. This is meant to mimic | |
182 // the behavior of the |auto_close| parameter of FileDescriptor. | |
183 // Defaults to |false|. | |
184 bool ownership_passes_to_ipc_; | |
185 }; | |
186 }; | |
157 }; | 187 }; |
158 #endif | 188 #endif |
159 | 189 |
160 } // namespace base | 190 } // namespace base |
161 | 191 |
162 #endif // BASE_MEMORY_SHARED_MEMORY_HANDLE_H_ | 192 #endif // BASE_MEMORY_SHARED_MEMORY_HANDLE_H_ |
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