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 #include <sys/mman.h> 22 23 #include <android-base/unique_fd.h> 24 #include <android/media/SharedFileRegion.h> 25 26 namespace aaudio { 27 28 // Arbitrary limits for range checks. 29 #define MAX_SHARED_MEMORIES (32) 30 #define MAX_MMAP_OFFSET_BYTES (32 * 1024 * 8) 31 #define MAX_MMAP_SIZE_BYTES (32 * 1024 * 8) 32 33 /** 34 * This is a parcelable description of a shared memory referenced by a file descriptor. 35 * It may be divided into several regions. 36 * The memory can be shared using Binder or simply shared between threads. 37 */ 38 class SharedMemoryParcelable { 39 public: 40 SharedMemoryParcelable() = default; 41 42 // Ctor from a parcelable representation. 43 // Since the parcelable object owns a unique FD, move semantics are provided to avoid the need 44 // to dupe. 45 explicit SharedMemoryParcelable(android::media::SharedFileRegion&& parcelable); 46 47 /** 48 * Make a dup() of the fd and store it for later use. 49 * 50 * @param fd 51 * @param sizeInBytes 52 */ 53 void setup(const android::base::unique_fd& fd, int32_t sizeInBytes); 54 55 // mmap() shared memory 56 aaudio_result_t resolve(int32_t offsetInBytes, int32_t sizeInBytes, void **regionAddressPtr); 57 58 // munmap() any mapped memory 59 aaudio_result_t close(); 60 61 int32_t getSizeInBytes(); 62 63 void dump(); 64 65 // Extract a parcelable representation of this object. 66 // Since we own a unique FD, move semantics are provided to avoid the need to dupe. 67 android::media::SharedFileRegion parcelable() &&; 68 69 // Copy this instance. Duplicates the underlying FD. 70 SharedMemoryParcelable dup() const; 71 72 private: 73 #define MMAP_UNRESOLVED_ADDRESS reinterpret_cast<uint8_t*>(MAP_FAILED) 74 75 android::base::unique_fd mFd; 76 int64_t mSizeInBytes = 0; 77 int64_t mOffsetInBytes = 0; 78 uint8_t *mResolvedAddress = MMAP_UNRESOLVED_ADDRESS; 79 80 aaudio_result_t resolveSharedMemory(const android::base::unique_fd& fd); 81 aaudio_result_t validate() const; 82 }; 83 84 } /* namespace aaudio */ 85 86 #endif //ANDROID_AAUDIO_SHARED_MEMORY_PARCELABLE_H 87