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1 /*
2  * Copyright 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 ANDROID_AAUDIO_SHARED_MEMORY_PARCELABLE_H
18 #define ANDROID_AAUDIO_SHARED_MEMORY_PARCELABLE_H
19 
20 #include <stdint.h>
21 
22 #include <sys/mman.h>
23 #include <binder/Parcel.h>
24 #include <binder/Parcelable.h>
25 
26 using android::status_t;
27 using android::Parcel;
28 using android::Parcelable;
29 
30 namespace aaudio {
31 
32 // Arbitrary limits for sanity checks. TODO remove after debugging.
33 #define MAX_SHARED_MEMORIES (32)
34 #define MAX_MMAP_OFFSET_BYTES (32 * 1024 * 8)
35 #define MAX_MMAP_SIZE_BYTES (32 * 1024 * 8)
36 
37 /**
38  * This is a parcelable description of a shared memory referenced by a file descriptor.
39  * It may be divided into several regions.
40  */
41 class SharedMemoryParcelable : public Parcelable {
42 public:
43     SharedMemoryParcelable();
44     virtual ~SharedMemoryParcelable();
45 
46     void setup(int fd, int32_t sizeInBytes);
47 
48     virtual status_t writeToParcel(Parcel* parcel) const override;
49 
50     virtual status_t readFromParcel(const Parcel* parcel) override;
51 
52     // mmap() shared memory
53     aaudio_result_t resolve(int32_t offsetInBytes, int32_t sizeInBytes, void **regionAddressPtr);
54 
55     // munmap() any mapped memory
56     aaudio_result_t close();
57 
58     bool isFileDescriptorSafe();
59 
60     int32_t getSizeInBytes();
61 
62     aaudio_result_t validate();
63 
64     void dump();
65 
66 protected:
67 
68 #define MMAP_UNRESOLVED_ADDRESS    reinterpret_cast<uint8_t*>(MAP_FAILED)
69 
70     int      mFd = -1;
71     int      mOriginalFd = -1;
72     int32_t  mSizeInBytes = 0;
73     uint8_t *mResolvedAddress = MMAP_UNRESOLVED_ADDRESS;
74 };
75 
76 } /* namespace aaudio */
77 
78 #endif //ANDROID_AAUDIO_SHARED_MEMORY_PARCELABLE_H
79