1 /*
2  * Copyright (C) 2017 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 #define LOG_TAG "AAudioService"
18 //#define LOG_NDEBUG 0
19 #include <utils/Log.h>
20 
21 #include <aaudio/AAudio.h>
22 #include "SharedMemoryProxy.h"
23 
24 using namespace android;
25 using namespace aaudio;
26 
~SharedMemoryProxy()27 SharedMemoryProxy::~SharedMemoryProxy()
28 {
29     if (mOriginalSharedMemory != nullptr) {
30         munmap(mOriginalSharedMemory, mSharedMemorySizeInBytes);
31         mOriginalSharedMemory = nullptr;
32     }
33     if (mProxySharedMemory != nullptr) {
34         munmap(mProxySharedMemory, mSharedMemorySizeInBytes);
35         close(mProxyFileDescriptor);
36         mProxySharedMemory = nullptr;
37     }
38 }
39 
open(int originalFD,int32_t capacityInBytes)40 aaudio_result_t SharedMemoryProxy::open(int originalFD, int32_t capacityInBytes) {
41     mOriginalFileDescriptor = originalFD;
42     mSharedMemorySizeInBytes = capacityInBytes;
43 
44     mProxyFileDescriptor = ashmem_create_region("AAudioProxyDataBuffer", mSharedMemorySizeInBytes);
45     if (mProxyFileDescriptor < 0) {
46         ALOGE("SharedMemoryProxy::open() ashmem_create_region() failed %d", errno);
47         return AAUDIO_ERROR_INTERNAL;
48     }
49     int err = ashmem_set_prot_region(mProxyFileDescriptor, PROT_READ|PROT_WRITE);
50     if (err < 0) {
51         ALOGE("SharedMemoryProxy::open() ashmem_set_prot_region() failed %d", errno);
52         close(mProxyFileDescriptor);
53         mProxyFileDescriptor = -1;
54         return AAUDIO_ERROR_INTERNAL; // TODO convert errno to a better AAUDIO_ERROR;
55     }
56 
57     // Get original memory address.
58     mOriginalSharedMemory = (uint8_t *) mmap(0, mSharedMemorySizeInBytes,
59                          PROT_READ|PROT_WRITE,
60                          MAP_SHARED,
61                          mOriginalFileDescriptor, 0);
62     if (mOriginalSharedMemory == MAP_FAILED) {
63         ALOGE("SharedMemoryProxy::open() original mmap(%d) failed %d (%s)",
64                 mOriginalFileDescriptor, errno, strerror(errno));
65         return AAUDIO_ERROR_INTERNAL; // TODO convert errno to a better AAUDIO_ERROR;
66     }
67 
68     // Map the fd to the same memory addresses.
69     mProxySharedMemory = (uint8_t *) mmap(mOriginalSharedMemory, mSharedMemorySizeInBytes,
70                          PROT_READ|PROT_WRITE,
71                          MAP_SHARED,
72                          mProxyFileDescriptor, 0);
73     if (mProxySharedMemory != mOriginalSharedMemory) {
74         ALOGE("SharedMemoryProxy::open() proxy mmap(%d) failed %d", mProxyFileDescriptor, errno);
75         munmap(mOriginalSharedMemory, mSharedMemorySizeInBytes);
76         mOriginalSharedMemory = nullptr;
77         close(mProxyFileDescriptor);
78         mProxyFileDescriptor = -1;
79         return AAUDIO_ERROR_INTERNAL; // TODO convert errno to a better AAUDIO_ERROR;
80     }
81 
82     return AAUDIO_OK;
83 }
84