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 static_assert(!std::is_signed_v<T>);
38 T result = AlignUp(x, kPageSize);
39 CHECK_GE(result, x);
40 return result;
41 }
42
43 template <typename T>
AlignUpPageSizeOverflow(T x,T * result)44 constexpr bool AlignUpPageSizeOverflow(T x, T* result) {
45 static_assert(!std::is_signed_v<T>);
46 *result = AlignUp(x, kPageSize);
47 return *result < x;
48 }
49
50 template <typename T>
IsAlignedPageSize(T x)51 constexpr bool IsAlignedPageSize(T x) {
52 return IsAligned(x, kPageSize);
53 }
54
55 enum MmapBerberisFlags {
56 kMmapBerberis32Bit = 1,
57 };
58
59 struct MmapImplArgs {
60 void* addr = nullptr;
61 size_t size = 0;
62 int prot = PROT_READ | PROT_WRITE;
63 int flags = MAP_PRIVATE | MAP_ANONYMOUS;
64 int fd = -1;
65 off_t offset = 0;
66 int berberis_flags = 0;
67 };
68
69 void* MmapImpl(MmapImplArgs args);
70 void* MmapImplOrDie(MmapImplArgs args);
71
Mmap(size_t size)72 inline void* Mmap(size_t size) {
73 return MmapImpl({.size = size});
74 }
75
MmapOrDie(size_t size)76 inline void* MmapOrDie(size_t size) {
77 return MmapImplOrDie({.size = size});
78 }
79
80 void MunmapOrDie(void* ptr, size_t size);
81
82 void MprotectOrDie(void* ptr, size_t size, int prot);
83
84 class ScopedMmap {
85 public:
ScopedMmap()86 ScopedMmap() : data_(nullptr), size_(0) {}
ScopedMmap(size_t size)87 explicit ScopedMmap(size_t size) { Init(size); }
88
~ScopedMmap()89 ~ScopedMmap() {
90 if (size_) {
91 MunmapOrDie(data_, size_);
92 }
93 }
94
Init(size_t size)95 void Init(size_t size) {
96 size_ = AlignUpPageSize(size);
97 data_ = MmapOrDie(size_);
98 }
99
data()100 void* data() const { return data_; }
size()101 size_t size() const { return size_; }
102
103 private:
104 void* data_;
105 size_t size_;
106
107 DISALLOW_COPY_AND_ASSIGN(ScopedMmap);
108 };
109
110 } // namespace berberis
111
112 #endif // BERBERIS_BASE_MMAP_H_
113