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 _FMSGQ_DESCRIPTOR_H
18 #define _FMSGQ_DESCRIPTOR_H
19 
20 #include <unistd.h>
21 
22 #include <cutils/native_handle.h>
23 #include <fmq/MQDescriptorBase.h>
24 #include <hidl/HidlInternal.h>
25 #include <hidl/HidlSupport.h>
26 
27 namespace android {
28 namespace hardware {
29 
30 template <typename T, MQFlavor flavor>
31 struct MQDescriptor {
32     // Takes ownership of handle
33     MQDescriptor(
34             const std::vector<GrantorDescriptor>& grantors,
35             native_handle_t* nHandle, size_t size);
36 
37     // Takes ownership of handle
38     MQDescriptor(size_t bufferSize, native_handle_t* nHandle,
39                  size_t messageSize, bool configureEventFlag = false);
40 
41     MQDescriptor();
42     ~MQDescriptor();
43 
44     explicit MQDescriptor(const MQDescriptor& other) : MQDescriptor() { *this = other; }
45     MQDescriptor& operator=(const MQDescriptor& other);
46 
47     size_t getSize() const;
48 
49     size_t getQuantum() const;
50 
51     int32_t getFlags() const;
52 
53     bool isHandleValid() const { return mHandle != nullptr; }
54     size_t countGrantors() const { return mGrantors.size(); }
55 
56     inline const ::android::hardware::hidl_vec<GrantorDescriptor> &grantors() const {
57         return mGrantors;
58     }
59 
60     inline const ::native_handle_t *handle() const {
61         return mHandle;
62     }
63 
64     inline ::native_handle_t *handle() {
65         return mHandle;
66     }
67 
68     static const size_t kOffsetOfGrantors;
69     static const size_t kOffsetOfHandle;
70 
71 private:
72     ::android::hardware::hidl_vec<GrantorDescriptor> mGrantors;
73     ::android::hardware::details::hidl_pointer<native_handle_t> mHandle;
74     uint32_t mQuantum;
75     uint32_t mFlags;
76 };
77 
78 template<typename T, MQFlavor flavor>
79 const size_t MQDescriptor<T, flavor>::kOffsetOfGrantors = offsetof(MQDescriptor, mGrantors);
80 
81 template<typename T, MQFlavor flavor>
82 const size_t MQDescriptor<T, flavor>::kOffsetOfHandle = offsetof(MQDescriptor, mHandle);
83 
84 /*
85  * MQDescriptorSync will describe the wait-free synchronized
86  * flavor of FMQ.
87  */
88 template<typename T>
89 using MQDescriptorSync = MQDescriptor<T, kSynchronizedReadWrite>;
90 
91 /*
92  * MQDescriptorUnsync will describe the unsynchronized write
93  * flavor of FMQ.
94  */
95 template<typename T>
96 using MQDescriptorUnsync = MQDescriptor<T, kUnsynchronizedWrite>;
97 
98 template <typename T, MQFlavor flavor>
99 MQDescriptor<T, flavor>::MQDescriptor(const std::vector<GrantorDescriptor>& grantors,
100                                       native_handle_t* nhandle, size_t size)
101     : mHandle(nhandle), mQuantum(static_cast<uint32_t>(size)), mFlags(flavor) {
102     mGrantors.resize(grantors.size());
103     for (size_t i = 0; i < grantors.size(); ++i) {
104         mGrantors[i] = grantors[i];
105     }
106 }
107 
108 template <typename T, MQFlavor flavor>
109 MQDescriptor<T, flavor>::MQDescriptor(size_t bufferSize, native_handle_t* nHandle,
110                                       size_t messageSize, bool configureEventFlag)
111     : mHandle(nHandle), mQuantum(static_cast<uint32_t>(messageSize)), mFlags(flavor) {
112     /*
113      * If configureEventFlag is true, allocate an additional spot in mGrantor
114      * for containing the fd and offset for mmapping the EventFlag word.
115      */
116     mGrantors.resize(configureEventFlag ? details::kMinGrantorCountForEvFlagSupport
117                                         : details::kMinGrantorCount);
118 
119     size_t memSize[] = {
120             sizeof(details::RingBufferPosition), /* memory to be allocated for read pointer counter
121                                                   */
122             sizeof(details::RingBufferPosition), /* memory to be allocated for write pointer counter
123                                                   */
124             bufferSize,                          /* memory to be allocated for data buffer */
125             sizeof(std::atomic<uint32_t>)        /* memory to be allocated for EventFlag word */
126     };
127 
128     /*
129      * Create a default grantor descriptor for read, write pointers and
130      * the data buffer. fdIndex parameter is set to 0 by default and
131      * the offset for each grantor is contiguous.
132      */
133     for (size_t grantorPos = 0, offset = 0;
134          grantorPos < mGrantors.size();
135          offset += memSize[grantorPos++]) {
136         mGrantors[grantorPos] = {0 /* grantor flags */, 0 /* fdIndex */,
137                                  static_cast<uint32_t>(details::alignToWordBoundary(offset)),
138                                  memSize[grantorPos]};
139     }
140 }
141 
142 template <typename T, MQFlavor flavor>
143 MQDescriptor<T, flavor>& MQDescriptor<T, flavor>::operator=(const MQDescriptor& other) {
144     mGrantors = other.mGrantors;
145     if (mHandle != nullptr) {
146         native_handle_close(mHandle);
147         native_handle_delete(mHandle);
148         mHandle = nullptr;
149     }
150     mQuantum = other.mQuantum;
151     mFlags = other.mFlags;
152 
153     if (other.mHandle != nullptr) {
154         mHandle = native_handle_create(
155                 other.mHandle->numFds, other.mHandle->numInts);
156 
157         for (int i = 0; i < other.mHandle->numFds; ++i) {
158             mHandle->data[i] = dup(other.mHandle->data[i]);
159         }
160 
161         memcpy(&mHandle->data[other.mHandle->numFds], &other.mHandle->data[other.mHandle->numFds],
162                static_cast<size_t>(other.mHandle->numInts) * sizeof(int));
163     }
164 
165     return *this;
166 }
167 
168 template<typename T, MQFlavor flavor>
169 MQDescriptor<T, flavor>::MQDescriptor() : MQDescriptor(
170         std::vector<android::hardware::GrantorDescriptor>(),
171         nullptr /* nHandle */,
172         0 /* size */) {}
173 
174 template<typename T, MQFlavor flavor>
175 MQDescriptor<T, flavor>::~MQDescriptor() {
176     if (mHandle != nullptr) {
177         native_handle_close(mHandle);
178         native_handle_delete(mHandle);
179     }
180 }
181 
182 template<typename T, MQFlavor flavor>
183 size_t MQDescriptor<T, flavor>::getSize() const {
184     return static_cast<size_t>(mGrantors[details::DATAPTRPOS].extent);
185 }
186 
187 template<typename T, MQFlavor flavor>
188 size_t MQDescriptor<T, flavor>::getQuantum() const { return mQuantum; }
189 
190 template<typename T, MQFlavor flavor>
191 int32_t MQDescriptor<T, flavor>::getFlags() const { return mFlags; }
192 
193 template<typename T, MQFlavor flavor>
194 std::string toString(const MQDescriptor<T, flavor> &q) {
195     std::string os;
196     if (flavor & kSynchronizedReadWrite) {
197         os += "fmq_sync";
198     }
199     if (flavor & kUnsynchronizedWrite) {
200         os += "fmq_unsync";
201     }
202     os += " {"
203        + toString(q.grantors().size()) + " grantor(s), "
204        + "size = " + toString(q.getSize())
205        + ", .handle = " + toString(q.handle())
206        + ", .quantum = " + toString(q.getQuantum()) + "}";
207     return os;
208 }
209 
210 }  // namespace hardware
211 }  // namespace android
212 
213 #endif  // FMSGQ_DESCRIPTOR_H
214