ADHOC/replicant-frameworks_native
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Fix a race condition in sensormanager

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the per-connection state assumed the main sensorservice
lock was held during access. This is however not true while
pre-processing the events just before sending them to clients.
Therefore, there was a small window during which this state
could be modified while being used.

we now have an internal lock that protects this state.

Change-Id: I594680f20f09d6a4f1f38f093a1d3f650dcef1be
This commit is contained in:
Mathias Agopian 2010-11-14 20:55:25 -08:00
parent 94e8f6813f
commit 71d7a5c289
2 changed files with 8 additions and 1 deletions
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6
services/sensorservice/SensorService.cpp
View File

@ -464,6 +464,7 @@ void SensorService::SensorEventConnection::onFirstRef()
}
bool SensorService::SensorEventConnection::addSensor(int32_t handle) {
Mutex::Autolock _l(mConnectionLock);
if (mSensorInfo.indexOfKey(handle) <= 0) {
SensorInfo info;
mSensorInfo.add(handle, info);
@ -473,6 +474,7 @@ bool SensorService::SensorEventConnection::addSensor(int32_t handle) {
}
bool SensorService::SensorEventConnection::removeSensor(int32_t handle) {
Mutex::Autolock _l(mConnectionLock);
if (mSensorInfo.removeItem(handle) >= 0) {
return true;
}
@ -480,16 +482,19 @@ bool SensorService::SensorEventConnection::removeSensor(int32_t handle) {
}
bool SensorService::SensorEventConnection::hasSensor(int32_t handle) const {
Mutex::Autolock _l(mConnectionLock);
return mSensorInfo.indexOfKey(handle) >= 0;
}
bool SensorService::SensorEventConnection::hasAnySensor() const {
Mutex::Autolock _l(mConnectionLock);
return mSensorInfo.size() ? true : false;
}
status_t SensorService::SensorEventConnection::setEventRateLocked(
int handle, nsecs_t ns)
{
Mutex::Autolock _l(mConnectionLock);
ssize_t index = mSensorInfo.indexOfKey(handle);
if (index >= 0) {
SensorInfo& info = mSensorInfo.editValueFor(handle);
@ -506,6 +511,7 @@ status_t SensorService::SensorEventConnection::sendEvents(
// filter out events not for this connection
size_t count = 0;
if (scratch) {
Mutex::Autolock _l(mConnectionLock);
size_t i=0;
while (i<numEvents) {
const int32_t curr = buffer[i].sensor;

3
services/sensorservice/SensorService.h
View File

@ -75,8 +75,9 @@ class SensorService :
sp<SensorService> const mService;
sp<SensorChannel> const mChannel;
mutable Mutex mConnectionLock;
// protected by SensorService::mLock
// protected mConnectionLock
struct SensorInfo {
SensorInfo() : ns(DEFAULT_EVENTS_PERIOD) { }
nsecs_t ns;