1 /*
2 * Copyright (C) 2016 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #ifndef BERBERIS_BASE_MMAP_H_
18 #define BERBERIS_BASE_MMAP_H_
19
20 #include <sys/mman.h>
21
22 #include <cstddef>
23
24 #include "berberis/base/bit_util.h"
25 #include "berberis/base/macros.h"
26 #include "berberis/base/page_size.h"
27
28 namespace berberis {
29
30 template <typename T>
AlignDownPageSize(T x)31 constexpr T AlignDownPageSize(T x) {
32 return AlignDown(x, kPageSize);
33 }
34
35 template <typename T>
AlignUpPageSize(T x)36 constexpr T AlignUpPageSize(T x) {
37 return AlignUp(x, kPageSize);
38 }
39
40 template <typename T>
IsAlignedPageSize(T x)41 constexpr bool IsAlignedPageSize(T x) {
42 return IsAligned(x, kPageSize);
43 }
44
45 struct MmapImplArgs {
46 void* addr = nullptr;
47 size_t size = 0;
48 int prot = PROT_READ | PROT_WRITE;
49 int flags = MAP_PRIVATE | MAP_ANONYMOUS;
50 int fd = -1;
51 off_t offset = 0;
52 };
53
54 void* MmapImpl(MmapImplArgs args);
55 void* MmapImplOrDie(MmapImplArgs args);
56
Mmap(size_t size)57 inline void* Mmap(size_t size) {
58 return MmapImpl({.size = size});
59 }
60
MmapOrDie(size_t size)61 inline void* MmapOrDie(size_t size) {
62 return MmapImplOrDie({.size = size});
63 }
64
65 void MunmapOrDie(void* ptr, size_t size);
66
67 void MprotectOrDie(void* ptr, size_t size, int prot);
68
69 class ScopedMmap {
70 public:
ScopedMmap()71 ScopedMmap() : data_(nullptr), size_(0) {}
ScopedMmap(size_t size)72 explicit ScopedMmap(size_t size) { Init(size); }
73
~ScopedMmap()74 ~ScopedMmap() {
75 if (size_) {
76 MunmapOrDie(data_, size_);
77 }
78 }
79
Init(size_t size)80 void Init(size_t size) {
81 size_ = AlignUpPageSize(size);
82 data_ = MmapOrDie(size_);
83 }
84
data()85 void* data() const { return data_; }
size()86 size_t size() const { return size_; }
87
88 private:
89 void* data_;
90 size_t size_;
91
92 DISALLOW_COPY_AND_ASSIGN(ScopedMmap);
93 };
94
95 } // namespace berberis
96
97 #endif // BERBERIS_BASE_MMAP_H_
98