SensorService.h revision 4949c50372de4c7fdb57de1dc0c1f5bb3ac463eb 
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#include <utils/String8.h>
31
32#include <binder/BinderService.h>
33
34#include <gui/Sensor.h>
35#include <gui/BitTube.h>
36#include <gui/ISensorServer.h>
37#include <gui/ISensorEventConnection.h>
38
39#include "SensorInterface.h"
40
41#if __clang__
42// Clang warns about SensorEventConnection::dump hiding BBinder::dump
43// The cause isn't fixable without changing the API, so let's tell clang
44// this is indeed intentional.
45#pragma clang diagnostic ignored "-Woverloaded-virtual"
46#endif
47
48// ---------------------------------------------------------------------------
49
50#define DEBUG_CONNECTIONS   false
51// Max size is 100 KB which is enough to accept a batch of about 1000 events.
52#define MAX_SOCKET_BUFFER_SIZE_BATCHED 100 * 1024
53// For older HALs which don't support batching, use a smaller socket buffer size.
54#define SOCKET_BUFFER_SIZE_NON_BATCHED 4 * 1024
55
56struct sensors_poll_device_t;
57struct sensors_module_t;
58
59namespace android {
60// ---------------------------------------------------------------------------
61
62class SensorService :
63        public BinderService<SensorService>,
64        public BnSensorServer,
65        protected Thread
66{
67    friend class BinderService<SensorService>;
68
69    enum Mode {
70       // The regular operating mode where any application can register/unregister/call flush on
71       // sensors.
72       NORMAL = 0,
73       // This mode is used only for testing sensors. Each sensor can be tested in isolation with
74       // the required sampling_rate and maxReportLatency parameters without having to think about
75       // the data rates requested by other applications. End user devices are always expected to be
76       // in NORMAL mode. When this mode is first activated, all active sensors from all connections
77       // are disabled. Calling flush() will return an error. In this mode, only the requests from
78       // selected apps whose package names are whitelisted are allowed (typically CTS apps).  Only
79       // these apps can register/unregister/call flush() on sensors.  If SensorService switches to
80       // NORMAL mode again, all sensors that were previously registered to are activated with the
81       // corresponding paramaters if the application hasn't unregistered for sensors in the mean
82       // time.
83       // NOTE: Non whitelisted app whose sensors were previously deactivated may still receive
84       // events if a whitelisted app requests data from the same sensor.
85       RESTRICTED,
86       // TODO: This mode hasn't been implemented yet.
87       DATA_INJECTION
88    };
89
90    static const char* WAKE_LOCK_NAME;
91
92    static char const* getServiceName() ANDROID_API { return "sensorservice"; }
93    SensorService() ANDROID_API;
94    virtual ~SensorService();
95
96    virtual void onFirstRef();
97
98    // Thread interface
99    virtual bool threadLoop();
100
101    // ISensorServer interface
102    virtual Vector<Sensor> getSensorList();
103    virtual sp<ISensorEventConnection> createSensorEventConnection(const String8& packageName);
104    virtual status_t dump(int fd, const Vector<String16>& args);
105
106    class SensorEventConnection : public BnSensorEventConnection, public LooperCallback {
107        friend class SensorService;
108        virtual ~SensorEventConnection();
109        virtual void onFirstRef();
110        virtual sp<BitTube> getSensorChannel() const;
111        virtual status_t enableDisable(int handle, bool enabled, nsecs_t samplingPeriodNs,
112                                       nsecs_t maxBatchReportLatencyNs, int reservedFlags);
113        virtual status_t setEventRate(int handle, nsecs_t samplingPeriodNs);
114        virtual status_t flush();
115        // Count the number of flush complete events which are about to be dropped in the buffer.
116        // Increment mPendingFlushEventsToSend in mSensorInfo. These flush complete events will be
117        // sent separately before the next batch of events.
118        void countFlushCompleteEventsLocked(sensors_event_t const* scratch, int numEventsDropped);
119
120        // Check if there are any wake up events in the buffer. If yes, return the index of the
121        // first wake_up sensor event in the buffer else return -1. This wake_up sensor event will
122        // have the flag WAKE_UP_SENSOR_EVENT_NEEDS_ACK set. Exactly one event per packet will have
123        // the wake_up flag set. SOCK_SEQPACKET ensures that either the entire packet is read or
124        // dropped.
125        int findWakeUpSensorEventLocked(sensors_event_t const* scratch, int count);
126
127        // Send pending flush_complete events. There may have been flush_complete_events that are
128        // dropped which need to be sent separately before other events. On older HALs (1_0) this
129        // method emulates the behavior of flush().
130        void sendPendingFlushEventsLocked();
131
132        // Writes events from mEventCache to the socket.
133        void writeToSocketFromCache();
134
135        // Compute the approximate cache size from the FIFO sizes of various sensors registered for
136        // this connection. Wake up and non-wake up sensors have separate FIFOs but FIFO may be
137        // shared amongst wake-up sensors and non-wake up sensors.
138        int computeMaxCacheSizeLocked() const;
139
140        // When more sensors register, the maximum cache size desired may change. Compute max cache
141        // size, reallocate memory and copy over events from the older cache.
142        void reAllocateCacheLocked(sensors_event_t const* scratch, int count);
143
144        // LooperCallback method. If there is data to read on this fd, it is an ack from the
145        // app that it has read events from a wake up sensor, decrement mWakeLockRefCount.
146        // If this fd is available for writing send the data from the cache.
147        virtual int handleEvent(int fd, int events, void* data);
148
149        // Increment mPendingFlushEventsToSend for the given sensor handle.
150        void incrementPendingFlushCount(int32_t handle);
151
152        // Add or remove the file descriptor associated with the BitTube to the looper. If mDead is
153        // set to true or there are no more sensors for this connection, the file descriptor is
154        // removed if it has been previously added to the Looper. Depending on the state of the
155        // connection FD may be added to the Looper. The flags to set are determined by the internal
156        // state of the connection. FDs are added to the looper when wake-up sensors are registered
157        // (to poll for acknowledgements) and when write fails on the socket when there are too many
158        // error and the other end hangs up or when this client unregisters for this connection.
159        void updateLooperRegistration(const sp<Looper>& looper);
160        void updateLooperRegistrationLocked(const sp<Looper>& looper);
161
162        sp<SensorService> const mService;
163        sp<BitTube> mChannel;
164        uid_t mUid;
165        mutable Mutex mConnectionLock;
166        // Number of events from wake up sensors which are still pending and haven't been delivered
167        // to the corresponding application. It is incremented by one unit for each write to the
168        // socket.
169        uint32_t mWakeLockRefCount;
170
171        // If this flag is set to true, it means that the file descriptor associated with the
172        // BitTube has been added to the Looper in SensorService. This flag is typically set when
173        // this connection has wake-up sensors associated with it or when write has failed on this
174        // connection and we're storing some events in the cache.
175        bool mHasLooperCallbacks;
176        // If there are any errors associated with the Looper this flag is set to true and
177        // mWakeLockRefCount is reset to zero. needsWakeLock method will always return false, if
178        // this flag is set.
179        bool mDead;
180        struct FlushInfo {
181            // The number of flush complete events dropped for this sensor is stored here.
182            // They are sent separately before the next batch of events.
183            int mPendingFlushEventsToSend;
184            // Every activate is preceded by a flush. Only after the first flush complete is
185            // received, the events for the sensor are sent on that *connection*.
186            bool mFirstFlushPending;
187            FlushInfo() : mPendingFlushEventsToSend(0), mFirstFlushPending(false) {}
188        };
189        // protected by SensorService::mLock. Key for this vector is the sensor handle.
190        KeyedVector<int, FlushInfo> mSensorInfo;
191        sensors_event_t *mEventCache;
192        int mCacheSize, mMaxCacheSize;
193        String8 mPackageName;
194
195#if DEBUG_CONNECTIONS
196        int mEventsReceived, mEventsSent, mEventsSentFromCache;
197        int mTotalAcksNeeded, mTotalAcksReceived;
198#endif
199
200    public:
201        SensorEventConnection(const sp<SensorService>& service, uid_t uid, String8 packageName);
202
203        status_t sendEvents(sensors_event_t const* buffer, size_t count,
204                sensors_event_t* scratch,
205                SensorEventConnection const * const * mapFlushEventsToConnections = NULL);
206        bool hasSensor(int32_t handle) const;
207        bool hasAnySensor() const;
208        bool hasOneShotSensors() const;
209        bool addSensor(int32_t handle);
210        bool removeSensor(int32_t handle);
211        void setFirstFlushPending(int32_t handle, bool value);
212        void dump(String8& result);
213        bool needsWakeLock();
214        void resetWakeLockRefCount();
215        String8 getPackageName() const;
216
217        uid_t getUid() const { return mUid; }
218    };
219
220    class SensorRecord {
221        SortedVector< wp<SensorEventConnection> > mConnections;
222        // A queue of all flush() calls made on this sensor. Flush complete events will be
223        // sent in this order.
224        Vector< wp<SensorEventConnection> > mPendingFlushConnections;
225    public:
226        SensorRecord(const sp<SensorEventConnection>& connection);
227        bool addConnection(const sp<SensorEventConnection>& connection);
228        bool removeConnection(const wp<SensorEventConnection>& connection);
229        size_t getNumConnections() const { return mConnections.size(); }
230
231        void addPendingFlushConnection(const sp<SensorEventConnection>& connection);
232        void removeFirstPendingFlushConnection();
233        SensorEventConnection * getFirstPendingFlushConnection();
234        void clearAllPendingFlushConnections();
235    };
236
237    class SensorEventAckReceiver : public Thread {
238        sp<SensorService> const mService;
239    public:
240        virtual bool threadLoop();
241        SensorEventAckReceiver(const sp<SensorService>& service): mService(service) {}
242    };
243
244    String8 getSensorName(int handle) const;
245    bool isVirtualSensor(int handle) const;
246    Sensor getSensorFromHandle(int handle) const;
247    bool isWakeUpSensor(int type) const;
248    void recordLastValueLocked(sensors_event_t const* buffer, size_t count);
249    static void sortEventBuffer(sensors_event_t* buffer, size_t count);
250    Sensor registerSensor(SensorInterface* sensor);
251    Sensor registerVirtualSensor(SensorInterface* sensor);
252    status_t cleanupWithoutDisable(
253            const sp<SensorEventConnection>& connection, int handle);
254    status_t cleanupWithoutDisableLocked(
255            const sp<SensorEventConnection>& connection, int handle);
256    void cleanupAutoDisabledSensorLocked(const sp<SensorEventConnection>& connection,
257            sensors_event_t const* buffer, const int count);
258    static bool canAccessSensor(const Sensor& sensor);
259    static bool verifyCanAccessSensor(const Sensor& sensor, const char* operation);
260    // SensorService acquires a partial wakelock for delivering events from wake up sensors. This
261    // method checks whether all the events from these wake up sensors have been delivered to the
262    // corresponding applications, if yes the wakelock is released.
263    void checkWakeLockState();
264    void checkWakeLockStateLocked();
265    bool isWakeLockAcquired();
266    bool isWakeUpSensorEvent(const sensors_event_t& event) const;
267
268    SensorRecord * getSensorRecord(int handle);
269
270    sp<Looper> getLooper() const;
271
272    // Reset mWakeLockRefCounts for all SensorEventConnections to zero. This may happen if
273    // SensorService did not receive any acknowledgements from apps which have registered for
274    // wake_up sensors.
275    void resetAllWakeLockRefCounts();
276
277    // Acquire or release wake_lock. If wake_lock is acquired, set the timeout in the looper to
278    // 5 seconds and wake the looper.
279    void setWakeLockAcquiredLocked(bool acquire);
280
281    // Send events from the event cache for this particular connection.
282    void sendEventsFromCache(const sp<SensorEventConnection>& connection);
283
284    // Promote all weak referecences in mActiveConnections vector to strong references and add them
285    // to the output vector.
286    void populateActiveConnections(SortedVector< sp<SensorEventConnection> >* activeConnections);
287
288    // If SensorService is operating in RESTRICTED mode, only select whitelisted packages are
289    // allowed to register for or call flush on sensors. Typically only cts test packages are
290    // allowed.
291    bool isWhiteListedPackage(const String8& packageName);
292
293    // constants
294    Vector<Sensor> mSensorList;
295    Vector<Sensor> mUserSensorListDebug;
296    Vector<Sensor> mUserSensorList;
297    DefaultKeyedVector<int, SensorInterface*> mSensorMap;
298    Vector<SensorInterface *> mVirtualSensorList;
299    status_t mInitCheck;
300    // Socket buffersize used to initialize BitTube. This size depends on whether batching is
301    // supported or not.
302    uint32_t mSocketBufferSize;
303    sp<Looper> mLooper;
304    sp<SensorEventAckReceiver> mAckReceiver;
305
306    // protected by mLock
307    mutable Mutex mLock;
308    DefaultKeyedVector<int, SensorRecord*> mActiveSensors;
309    DefaultKeyedVector<int, SensorInterface*> mActiveVirtualSensors;
310    SortedVector< wp<SensorEventConnection> > mActiveConnections;
311    bool mWakeLockAcquired;
312    sensors_event_t *mSensorEventBuffer, *mSensorEventScratch;
313    SensorEventConnection const **mMapFlushEventsToConnections;
314    Mode mMode;
315
316    // The size of this vector is constant, only the items are mutable
317    KeyedVector<int32_t, sensors_event_t> mLastEventSeen;
318
319public:
320    void cleanupConnection(SensorEventConnection* connection);
321    status_t enable(const sp<SensorEventConnection>& connection, int handle,
322                    nsecs_t samplingPeriodNs,  nsecs_t maxBatchReportLatencyNs, int reservedFlags);
323    status_t disable(const sp<SensorEventConnection>& connection, int handle);
324    status_t setEventRate(const sp<SensorEventConnection>& connection, int handle, nsecs_t ns);
325    status_t flushSensor(const sp<SensorEventConnection>& connection);
326};
327
328// ---------------------------------------------------------------------------
329}; // namespace android
330
331#endif // ANDROID_SENSOR_SERVICE_H
332