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1 // Copyright 2013 The Chromium Authors. All rights reserved. | 1 // Copyright 2013 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/files/memory_mapped_file.h" | 5 #include "base/files/memory_mapped_file.h" |
6 | 6 |
7 #include <stddef.h> | 7 #include <stddef.h> |
8 #include <stdint.h> | 8 #include <stdint.h> |
9 #include <sys/mman.h> | 9 #include <sys/mman.h> |
10 #include <sys/stat.h> | 10 #include <sys/stat.h> |
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24 const MemoryMappedFile::Region& region, | 24 const MemoryMappedFile::Region& region, |
25 Access access) { | 25 Access access) { |
26 ThreadRestrictions::AssertIOAllowed(); | 26 ThreadRestrictions::AssertIOAllowed(); |
27 | 27 |
28 off_t map_start = 0; | 28 off_t map_start = 0; |
29 size_t map_size = 0; | 29 size_t map_size = 0; |
30 int32_t data_offset = 0; | 30 int32_t data_offset = 0; |
31 | 31 |
32 if (region == MemoryMappedFile::Region::kWholeFile) { | 32 if (region == MemoryMappedFile::Region::kWholeFile) { |
33 int64_t file_len = file_.GetLength(); | 33 int64_t file_len = file_.GetLength(); |
34 if (file_len == -1) { | 34 if (file_len < 0) { |
35 DPLOG(ERROR) << "fstat " << file_.GetPlatformFile(); | 35 DPLOG(ERROR) << "fstat " << file_.GetPlatformFile(); |
36 return false; | 36 return false; |
37 } | 37 } |
38 map_size = static_cast<size_t>(file_len); | 38 map_size = static_cast<size_t>(file_len); |
39 length_ = map_size; | 39 length_ = map_size; |
40 } else { | 40 } else { |
41 // The region can be arbitrarily aligned. mmap, instead, requires both the | 41 // The region can be arbitrarily aligned. mmap, instead, requires both the |
42 // start and size to be page-aligned. Hence, we map here the page-aligned | 42 // start and size to be page-aligned. Hence, we map here the page-aligned |
43 // outer region [|aligned_start|, |aligned_start| + |size|] which contains | 43 // outer region [|aligned_start|, |aligned_start| + |size|] which contains |
44 // |region| and then add up the |data_offset| displacement. | 44 // |region| and then add up the |data_offset| displacement. |
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71 case READ_ONLY: | 71 case READ_ONLY: |
72 flags |= PROT_READ; | 72 flags |= PROT_READ; |
73 break; | 73 break; |
74 case READ_WRITE: | 74 case READ_WRITE: |
75 flags |= PROT_READ | PROT_WRITE; | 75 flags |= PROT_READ | PROT_WRITE; |
76 break; | 76 break; |
77 case READ_WRITE_EXTEND: | 77 case READ_WRITE_EXTEND: |
78 // POSIX won't auto-extend the file when it is written so it must first | 78 // POSIX won't auto-extend the file when it is written so it must first |
79 // be explicitly extended to the maximum size. Zeros will fill the new | 79 // be explicitly extended to the maximum size. Zeros will fill the new |
80 // space. | 80 // space. |
81 file_.SetLength(std::max(file_.GetLength(), region.offset + region.size)); | 81 auto file_len = file_.GetLength(); |
| 82 if (file_len < 0) { |
| 83 DPLOG(ERROR) << "fstat " << file_.GetPlatformFile(); |
| 84 return false; |
| 85 } |
| 86 file_.SetLength(std::max(file_len, region.offset + region.size)); |
82 flags |= PROT_READ | PROT_WRITE; | 87 flags |= PROT_READ | PROT_WRITE; |
83 break; | 88 break; |
84 } | 89 } |
85 data_ = static_cast<uint8_t*>(mmap(NULL, map_size, flags, MAP_SHARED, | 90 data_ = static_cast<uint8_t*>(mmap(NULL, map_size, flags, MAP_SHARED, |
86 file_.GetPlatformFile(), map_start)); | 91 file_.GetPlatformFile(), map_start)); |
87 if (data_ == MAP_FAILED) { | 92 if (data_ == MAP_FAILED) { |
88 DPLOG(ERROR) << "mmap " << file_.GetPlatformFile(); | 93 DPLOG(ERROR) << "mmap " << file_.GetPlatformFile(); |
89 return false; | 94 return false; |
90 } | 95 } |
91 | 96 |
92 data_ += data_offset; | 97 data_ += data_offset; |
93 return true; | 98 return true; |
94 } | 99 } |
95 #endif | 100 #endif |
96 | 101 |
97 void MemoryMappedFile::CloseHandles() { | 102 void MemoryMappedFile::CloseHandles() { |
98 ThreadRestrictions::AssertIOAllowed(); | 103 ThreadRestrictions::AssertIOAllowed(); |
99 | 104 |
100 if (data_ != NULL) | 105 if (data_ != NULL) |
101 munmap(data_, length_); | 106 munmap(data_, length_); |
102 file_.Close(); | 107 file_.Close(); |
103 | 108 |
104 data_ = NULL; | 109 data_ = NULL; |
105 length_ = 0; | 110 length_ = 0; |
106 } | 111 } |
107 | 112 |
108 } // namespace base | 113 } // namespace base |
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