1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
|
/*
* Copyright (C) 2008 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#pragma once
#include <stdlib.h>
#include <stdint.h>
#include <binder/Common.h>
#include <binder/IMemory.h>
namespace android {
// ---------------------------------------------------------------------------
class MemoryHeapBase : public BnMemoryHeap {
public:
static constexpr auto MEMFD_ALLOW_SEALING_FLAG = 0x00000800;
enum {
READ_ONLY = IMemoryHeap::READ_ONLY,
// memory won't be mapped locally, but will be mapped in the remote
// process.
DONT_MAP_LOCALLY = 0x00000100,
NO_CACHING = 0x00000200,
// Bypass ashmem-libcutils to create a memfd shared region.
// Ashmem-libcutils will eventually migrate to memfd.
// Memfd has security benefits and supports file sealing.
// Calling process will need to modify selinux permissions to
// open access to tmpfs files. See audioserver for examples.
// This is only valid for size constructor.
// For host compilation targets, memfd is stubbed in favor of /tmp
// files so sealing is not enforced.
FORCE_MEMFD = 0x00000400,
// Default opt-out of sealing behavior in memfd to avoid potential DOS.
// Clients of shared files can seal at anytime via syscall, leading to
// TOC/TOU issues if additional seals prevent access from the creating
// process. Alternatively, seccomp fcntl().
MEMFD_ALLOW_SEALING = FORCE_MEMFD | MEMFD_ALLOW_SEALING_FLAG
};
/*
* maps the memory referenced by fd. but DOESN'T take ownership
* of the filedescriptor (it makes a copy with dup()
*/
LIBBINDER_EXPORTED MemoryHeapBase(int fd, size_t size, uint32_t flags = 0, off_t offset = 0);
/*
* maps memory from the given device
*/
LIBBINDER_EXPORTED explicit MemoryHeapBase(const char* device, size_t size = 0,
uint32_t flags = 0);
/*
* maps memory from ashmem, with the given name for debugging
* if the READ_ONLY flag is set, the memory will be writeable by the calling process,
* but not by others. this is NOT the case with the other ctors.
*/
LIBBINDER_EXPORTED explicit MemoryHeapBase(size_t size, uint32_t flags = 0,
char const* name = nullptr);
LIBBINDER_EXPORTED virtual ~MemoryHeapBase();
/* implement IMemoryHeap interface */
LIBBINDER_EXPORTED int getHeapID() const override;
/* virtual address of the heap. returns MAP_FAILED in case of error */
LIBBINDER_EXPORTED void* getBase() const override;
LIBBINDER_EXPORTED size_t getSize() const override;
LIBBINDER_EXPORTED uint32_t getFlags() const override;
LIBBINDER_EXPORTED off_t getOffset() const override;
LIBBINDER_EXPORTED const char* getDevice() const;
/* this closes this heap -- use carefully */
LIBBINDER_EXPORTED void dispose();
protected:
LIBBINDER_EXPORTED MemoryHeapBase();
// init() takes ownership of fd
LIBBINDER_EXPORTED status_t init(int fd, void* base, size_t size, int flags = 0,
const char* device = nullptr);
private:
status_t mapfd(int fd, bool writeableByCaller, size_t size, off_t offset = 0);
int mFD;
size_t mSize;
void* mBase;
uint32_t mFlags;
const char* mDevice;
bool mNeedUnmap;
off_t mOffset;
};
// ---------------------------------------------------------------------------
} // namespace android
|
