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1 // Copyright (c) 2011 The Chromium Authors. All rights reserved. | 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 | 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 #include "base/memory/shared_memory.h" | 5 #include "base/memory/shared_memory.h" |
6 | 6 |
7 #include <stddef.h> | 7 #include <stddef.h> |
8 #include <sys/mman.h> | 8 #include <sys/mman.h> |
9 | 9 |
10 #include "base/logging.h" | 10 #include "base/logging.h" |
11 #include "third_party/ashmem/ashmem.h" | 11 #include "third_party/ashmem/ashmem.h" |
12 | 12 |
13 namespace base { | 13 namespace base { |
14 | 14 |
15 // For Android, we use ashmem to implement SharedMemory. ashmem_create_region | 15 // For Android, we use ashmem to implement SharedMemory. ashmem_create_region |
16 // will automatically pin the region. We never explicitly call pin/unpin. When | 16 // will automatically pin the region. We never explicitly call pin/unpin. When |
17 // all the file descriptors from different processes associated with the region | 17 // all the file descriptors from different processes associated with the region |
18 // are closed, the memory buffer will go away. | 18 // are closed, the memory buffer will go away. |
19 | 19 |
20 bool SharedMemory::Create(const SharedMemoryCreateOptions& options) { | 20 bool SharedMemory::Create(const SharedMemoryCreateOptions& options) { |
21 DCHECK(!shm_.IsValid()); | 21 DCHECK(!shm_.IsValid()); |
22 | 22 |
23 if (options.size > static_cast<size_t>(std::numeric_limits<int>::max())) | 23 if (options.size > static_cast<size_t>(std::numeric_limits<int>::max())) |
24 return false; | 24 return false; |
25 | 25 |
26 // "name" is just a label in ashmem. It is visible in /proc/pid/maps. | 26 // "name" is just a label in ashmem. It is visible in /proc/pid/maps. |
27 int fd = ashmem_create_region( | 27 int fd = ashmem_create_region( |
28 options.name_deprecated == NULL ? "" : options.name_deprecated->c_str(), | 28 options.name_deprecated == NULL ? "" : options.name_deprecated->c_str(), |
29 options.size); | 29 options.size); |
30 shm_ = SharedMemoryHandle::ImportHandle(fd); | 30 shm_ = SharedMemoryHandle::ImportHandle(fd, options.size); |
31 if (!shm_.IsValid()) { | 31 if (!shm_.IsValid()) { |
32 DLOG(ERROR) << "Shared memory creation failed"; | 32 DLOG(ERROR) << "Shared memory creation failed"; |
33 return false; | 33 return false; |
34 } | 34 } |
35 | 35 |
36 int err = ashmem_set_prot_region(shm_.GetHandle(), | 36 int err = ashmem_set_prot_region(shm_.GetHandle(), |
37 PROT_READ | PROT_WRITE | PROT_EXEC); | 37 PROT_READ | PROT_WRITE | PROT_EXEC); |
38 if (err < 0) { | 38 if (err < 0) { |
39 DLOG(ERROR) << "Error " << err << " when setting protection of ashmem"; | 39 DLOG(ERROR) << "Error " << err << " when setting protection of ashmem"; |
40 return false; | 40 return false; |
41 } | 41 } |
42 | 42 |
43 // Android doesn't appear to have a way to drop write access on an ashmem | 43 // Android doesn't appear to have a way to drop write access on an ashmem |
44 // segment for a single descriptor. http://crbug.com/320865 | 44 // segment for a single descriptor. http://crbug.com/320865 |
45 readonly_shm_ = SharedMemoryHandle( | 45 readonly_shm_ = shm_.Duplicate(); |
46 base::FileDescriptor(dup(shm_.GetHandle()), false), shm_.GetGUID()); | |
47 if (!readonly_shm_.IsValid()) { | 46 if (!readonly_shm_.IsValid()) { |
48 DPLOG(ERROR) << "dup() failed"; | 47 DPLOG(ERROR) << "dup() failed"; |
49 return false; | 48 return false; |
50 } | 49 } |
51 | 50 |
52 requested_size_ = options.size; | 51 requested_size_ = options.size; |
53 | 52 |
54 return true; | 53 return true; |
55 } | 54 } |
56 | 55 |
57 bool SharedMemory::Delete(const std::string& name) { | 56 bool SharedMemory::Delete(const std::string& name) { |
58 // Like on Windows, this is intentionally returning true as ashmem will | 57 // Like on Windows, this is intentionally returning true as ashmem will |
59 // automatically releases the resource when all FDs on it are closed. | 58 // automatically releases the resource when all FDs on it are closed. |
60 return true; | 59 return true; |
61 } | 60 } |
62 | 61 |
63 bool SharedMemory::Open(const std::string& name, bool read_only) { | 62 bool SharedMemory::Open(const std::string& name, bool read_only) { |
64 // ashmem doesn't support name mapping | 63 // ashmem doesn't support name mapping |
65 NOTIMPLEMENTED(); | 64 NOTIMPLEMENTED(); |
66 return false; | 65 return false; |
67 } | 66 } |
68 | 67 |
69 } // namespace base | 68 } // namespace base |
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