1 /*
2  * Copyright (C) 2010 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_SENSOR_SERVICE_H
18 #define ANDROID_SENSOR_SERVICE_H
19 
20 #include <stdint.h>
21 #include <sys/types.h>
22 
23 #include <utils/Vector.h>
24 #include <utils/SortedVector.h>
25 #include <utils/KeyedVector.h>
26 #include <utils/threads.h>
27 #include <utils/AndroidThreads.h>
28 #include <utils/RefBase.h>
29 #include <utils/Looper.h>
30 
31 #include <binder/BinderService.h>
32 
33 #include <gui/Sensor.h>
34 #include <gui/BitTube.h>
35 #include <gui/ISensorServer.h>
36 #include <gui/ISensorEventConnection.h>
37 
38 #include "SensorInterface.h"
39 
40 // ---------------------------------------------------------------------------
41 
42 #define DEBUG_CONNECTIONS   false
43 // Max size is 100 KB which is enough to accept a batch of about 1000 events.
44 #define MAX_SOCKET_BUFFER_SIZE_BATCHED 100 * 1024
45 // For older HALs which don't support batching, use a smaller socket buffer size.
46 #define SOCKET_BUFFER_SIZE_NON_BATCHED 4 * 1024
47 
48 struct sensors_poll_device_t;
49 struct sensors_module_t;
50 
51 namespace android {
52 // ---------------------------------------------------------------------------
53 
54 class SensorService :
55         public BinderService<SensorService>,
56         public BnSensorServer,
57         protected Thread
58 {
59     friend class BinderService<SensorService>;
60 
61     static const char* WAKE_LOCK_NAME;
62 
getServiceName()63     static char const* getServiceName() ANDROID_API { return "sensorservice"; }
64     SensorService() ANDROID_API;
65     virtual ~SensorService();
66 
67     virtual void onFirstRef();
68 
69     // Thread interface
70     virtual bool threadLoop();
71 
72     // ISensorServer interface
73     virtual Vector<Sensor> getSensorList();
74     virtual sp<ISensorEventConnection> createSensorEventConnection();
75     virtual status_t dump(int fd, const Vector<String16>& args);
76 
77     class SensorEventConnection : public BnSensorEventConnection, public LooperCallback {
78         friend class SensorService;
79         virtual ~SensorEventConnection();
80         virtual void onFirstRef();
81         virtual sp<BitTube> getSensorChannel() const;
82         virtual status_t enableDisable(int handle, bool enabled, nsecs_t samplingPeriodNs,
83                                        nsecs_t maxBatchReportLatencyNs, int reservedFlags);
84         virtual status_t setEventRate(int handle, nsecs_t samplingPeriodNs);
85         virtual status_t flush();
86         // Count the number of flush complete events which are about to be dropped in the buffer.
87         // Increment mPendingFlushEventsToSend in mSensorInfo. These flush complete events will be
88         // sent separately before the next batch of events.
89         void countFlushCompleteEventsLocked(sensors_event_t const* scratch, int numEventsDropped);
90 
91         // Check if there are any wake up events in the buffer. If yes, return the index of the
92         // first wake_up sensor event in the buffer else return -1. This wake_up sensor event will
93         // have the flag WAKE_UP_SENSOR_EVENT_NEEDS_ACK set. Exactly one event per packet will have
94         // the wake_up flag set. SOCK_SEQPACKET ensures that either the entire packet is read or
95         // dropped.
96         int findWakeUpSensorEventLocked(sensors_event_t const* scratch, int count);
97 
98         // Send pending flush_complete events. There may have been flush_complete_events that are
99         // dropped which need to be sent separately before other events. On older HALs (1_0) this
100         // method emulates the behavior of flush().
101         void sendPendingFlushEventsLocked();
102 
103         // Writes events from mEventCache to the socket.
104         void writeToSocketFromCache();
105 
106         // Compute the approximate cache size from the FIFO sizes of various sensors registered for
107         // this connection. Wake up and non-wake up sensors have separate FIFOs but FIFO may be
108         // shared amongst wake-up sensors and non-wake up sensors.
109         int computeMaxCacheSizeLocked() const;
110 
111         // When more sensors register, the maximum cache size desired may change. Compute max cache
112         // size, reallocate memory and copy over events from the older cache.
113         void reAllocateCacheLocked(sensors_event_t const* scratch, int count);
114 
115         // LooperCallback method. If there is data to read on this fd, it is an ack from the
116         // app that it has read events from a wake up sensor, decrement mWakeLockRefCount.
117         // If this fd is available for writing send the data from the cache.
118         virtual int handleEvent(int fd, int events, void* data);
119 
120         // Increment mPendingFlushEventsToSend for the given sensor handle.
121         void incrementPendingFlushCount(int32_t handle);
122 
123         // Add or remove the file descriptor associated with the BitTube to the looper. If mDead is
124         // set to true or there are no more sensors for this connection, the file descriptor is
125         // removed if it has been previously added to the Looper. Depending on the state of the
126         // connection FD may be added to the Looper. The flags to set are determined by the internal
127         // state of the connection. FDs are added to the looper when wake-up sensors are registered
128         // (to poll for acknowledgements) and when write fails on the socket when there are too many
129         // events (to poll when the FD is available for writing). FDs are removed when there is an
130         // error and the other end hangs up or when this client unregisters for this connection.
131         void updateLooperRegistration(const sp<Looper>& looper);
132         void updateLooperRegistrationLocked(const sp<Looper>& looper);
133 
134         sp<SensorService> const mService;
135         sp<BitTube> mChannel;
136         uid_t mUid;
137         mutable Mutex mConnectionLock;
138         // Number of events from wake up sensors which are still pending and haven't been delivered
139         // to the corresponding application. It is incremented by one unit for each write to the
140         // socket.
141         uint32_t mWakeLockRefCount;
142 
143         // If this flag is set to true, it means that the file descriptor associated with the
144         // BitTube has been added to the Looper in SensorService. This flag is typically set when
145         // this connection has wake-up sensors associated with it or when write has failed on this
146         // connection and we're storing some events in the cache.
147         bool mHasLooperCallbacks;
148         // If there are any errors associated with the Looper this flag is set to true and
149         // mWakeLockRefCount is reset to zero. needsWakeLock method will always return false, if
150         // this flag is set.
151         bool mDead;
152         struct FlushInfo {
153             // The number of flush complete events dropped for this sensor is stored here.
154             // They are sent separately before the next batch of events.
155             int mPendingFlushEventsToSend;
156             // Every activate is preceded by a flush. Only after the first flush complete is
157             // received, the events for the sensor are sent on that *connection*.
158             bool mFirstFlushPending;
FlushInfoFlushInfo159             FlushInfo() : mPendingFlushEventsToSend(0), mFirstFlushPending(false) {}
160         };
161         // protected by SensorService::mLock. Key for this vector is the sensor handle.
162         KeyedVector<int, FlushInfo> mSensorInfo;
163         sensors_event_t *mEventCache;
164         int mCacheSize, mMaxCacheSize;
165 
166 #if DEBUG_CONNECTIONS
167         int mEventsReceived, mEventsSent, mEventsSentFromCache;
168         int mTotalAcksNeeded, mTotalAcksReceived;
169 #endif
170 
171     public:
172         SensorEventConnection(const sp<SensorService>& service, uid_t uid);
173 
174         status_t sendEvents(sensors_event_t const* buffer, size_t count,
175                 sensors_event_t* scratch,
176                 SensorEventConnection const * const * mapFlushEventsToConnections = NULL);
177         bool hasSensor(int32_t handle) const;
178         bool hasAnySensor() const;
179         bool hasOneShotSensors() const;
180         bool addSensor(int32_t handle);
181         bool removeSensor(int32_t handle);
182         void setFirstFlushPending(int32_t handle, bool value);
183         void dump(String8& result);
184         bool needsWakeLock();
185         void resetWakeLockRefCount();
186 
getUid()187         uid_t getUid() const { return mUid; }
188     };
189 
190     class SensorRecord {
191         SortedVector< wp<SensorEventConnection> > mConnections;
192         // A queue of all flush() calls made on this sensor. Flush complete events will be
193         // sent in this order.
194         Vector< wp<SensorEventConnection> > mPendingFlushConnections;
195     public:
196         SensorRecord(const sp<SensorEventConnection>& connection);
197         bool addConnection(const sp<SensorEventConnection>& connection);
198         bool removeConnection(const wp<SensorEventConnection>& connection);
getNumConnections()199         size_t getNumConnections() const { return mConnections.size(); }
200 
201         void addPendingFlushConnection(const sp<SensorEventConnection>& connection);
202         void removeFirstPendingFlushConnection();
203         SensorEventConnection * getFirstPendingFlushConnection();
204     };
205 
206     class SensorEventAckReceiver : public Thread {
207         sp<SensorService> const mService;
208     public:
209         virtual bool threadLoop();
SensorEventAckReceiver(const sp<SensorService> & service)210         SensorEventAckReceiver(const sp<SensorService>& service): mService(service) {}
211     };
212 
213     String8 getSensorName(int handle) const;
214     bool isVirtualSensor(int handle) const;
215     Sensor getSensorFromHandle(int handle) const;
216     bool isWakeUpSensor(int type) const;
217     void recordLastValueLocked(sensors_event_t const* buffer, size_t count);
218     static void sortEventBuffer(sensors_event_t* buffer, size_t count);
219     Sensor registerSensor(SensorInterface* sensor);
220     Sensor registerVirtualSensor(SensorInterface* sensor);
221     status_t cleanupWithoutDisable(
222             const sp<SensorEventConnection>& connection, int handle);
223     status_t cleanupWithoutDisableLocked(
224             const sp<SensorEventConnection>& connection, int handle);
225     void cleanupAutoDisabledSensorLocked(const sp<SensorEventConnection>& connection,
226             sensors_event_t const* buffer, const int count);
227     static bool canAccessSensor(const Sensor& sensor);
228     static bool verifyCanAccessSensor(const Sensor& sensor, const char* operation);
229     // SensorService acquires a partial wakelock for delivering events from wake up sensors. This
230     // method checks whether all the events from these wake up sensors have been delivered to the
231     // corresponding applications, if yes the wakelock is released.
232     void checkWakeLockState();
233     void checkWakeLockStateLocked();
234     bool isWakeLockAcquired();
235     bool isWakeUpSensorEvent(const sensors_event_t& event) const;
236 
237     SensorRecord * getSensorRecord(int handle);
238 
239     sp<Looper> getLooper() const;
240 
241     // Reset mWakeLockRefCounts for all SensorEventConnections to zero. This may happen if
242     // SensorService did not receive any acknowledgements from apps which have registered for
243     // wake_up sensors.
244     void resetAllWakeLockRefCounts();
245 
246     // Acquire or release wake_lock. If wake_lock is acquired, set the timeout in the looper to
247     // 5 seconds and wake the looper.
248     void setWakeLockAcquiredLocked(bool acquire);
249 
250     // Send events from the event cache for this particular connection.
251     void sendEventsFromCache(const sp<SensorEventConnection>& connection);
252 
253     // Promote all weak referecences in mActiveConnections vector to strong references and add them
254     // to the output vector.
255     void populateActiveConnections(SortedVector< sp<SensorEventConnection> >* activeConnections);
256 
257     // constants
258     Vector<Sensor> mSensorList;
259     Vector<Sensor> mUserSensorListDebug;
260     Vector<Sensor> mUserSensorList;
261     DefaultKeyedVector<int, SensorInterface*> mSensorMap;
262     Vector<SensorInterface *> mVirtualSensorList;
263     status_t mInitCheck;
264     // Socket buffersize used to initialize BitTube. This size depends on whether batching is
265     // supported or not.
266     uint32_t mSocketBufferSize;
267     sp<Looper> mLooper;
268     sp<SensorEventAckReceiver> mAckReceiver;
269 
270     // protected by mLock
271     mutable Mutex mLock;
272     DefaultKeyedVector<int, SensorRecord*> mActiveSensors;
273     DefaultKeyedVector<int, SensorInterface*> mActiveVirtualSensors;
274     SortedVector< wp<SensorEventConnection> > mActiveConnections;
275     bool mWakeLockAcquired;
276     sensors_event_t *mSensorEventBuffer, *mSensorEventScratch;
277     SensorEventConnection const **mMapFlushEventsToConnections;
278 
279     // The size of this vector is constant, only the items are mutable
280     KeyedVector<int32_t, sensors_event_t> mLastEventSeen;
281 
282 public:
283     void cleanupConnection(SensorEventConnection* connection);
284     status_t enable(const sp<SensorEventConnection>& connection, int handle,
285                     nsecs_t samplingPeriodNs,  nsecs_t maxBatchReportLatencyNs, int reservedFlags);
286     status_t disable(const sp<SensorEventConnection>& connection, int handle);
287     status_t setEventRate(const sp<SensorEventConnection>& connection, int handle, nsecs_t ns);
288     status_t flushSensor(const sp<SensorEventConnection>& connection);
289 };
290 
291 // ---------------------------------------------------------------------------
292 }; // namespace android
293 
294 #endif // ANDROID_SENSOR_SERVICE_H
295