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// Written by Dmitry Grinberg
#define LOG_TAG "libgpsd-compat"
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <utils/Log.h>
#include <hardware/power.h>
#include <hardware/hardware.h>
/*
* Problems:
* 1. Nexus 10's GPS library was made to work with android L
* 2. Android M changed a few things around that make it not work
* a. Sensor manager API changed in a few places
* 3. Due to these now-missing unresolved symbols GPS library will not load or run
*/
//various funcs we'll need to call, in their mangled form
//android::String8::String8(char const*)
extern void _ZN7android7String8C1EPKc(void **str8P, const char *str);
//android::String8::~String8()
extern void _ZN7android7String8D1Ev(void **str8P);
//android::String16::String16(char const*)
extern void _ZN7android8String16C1EPKc(void **str16P, const char *str);
//android::String16::~String16()
extern void _ZN7android8String16D1Ev(void **str16P);
//android::SensorManager::~SensorManager()
extern void _ZN7android13SensorManagerD1Ev(void *sensorMgr);
//android::SensorManager::SensorManager(android::String16 const&)
extern void _ZN7android13SensorManagerC1ERKNS_8String16E(void *sensorMgr, void **str16P);
//android::SensorManager::createEventQueue(android::String8, int)
extern void _ZN7android13SensorManager16createEventQueueENS_7String8Ei(void **retVal, void *sensorMgr, void **str8P, int mode);
//data exports we must provide for gps library to be happy
/*
* DATA: android::Singleton<android::SensorManager>::sInstance
* USE: INTERPOSE: a singleton instance of SensorManager
* NOTES: In L, the sensor manager exposed this variable, as it was
* a singleton and one could just access this directly to get
* the current already-existing instance if it happened to
* already exist. If not one would create one and store it
* there. In M this is entirely different, but the GPS library
* does not know that. So we'll init it to NULL to signify that
* no current instance exists, let it create one, and store it
* here, and upon unloading we'll clean it up, if it is not
* NULL (which is what it would be if the GPS library itself
* did the cleanup).
*/
void* _ZN7android9SingletonINS_13SensorManagerEE9sInstanceE = NULL;
//code exports we provide
//android::SensorManager::SensorManager(void)
void _ZN7android13SensorManagerC1Ev(void *sensorMgr);
//android::SensorManager::createEventQueue(void)
void _ZN7android13SensorManager16createEventQueueEv(void **retVal, void *sensorMgr);
//library on-load and on-unload handlers (to help us set things up and tear them down)
void libEvtUnloading(void) __attribute__((destructor));
/*
* FUNCTION: android::SensorManager::SensorManager(void)
* USE: INTERPOSE: construct a sensor manager object
* NOTES: This constructor no longer exists in M, instead now one must pass
* in a package name as a "string16" to the consrtuctor. Since this
* lib only services GPS library, it is easy for us to just do that
* and this provide the constructor that the GPS library wants.
*/
void _ZN7android13SensorManagerC1Ev(void *sensorMgr)
{
void *string;
_ZN7android8String16C1EPKc(&string, "gps.tegra3");
_ZN7android13SensorManagerC1ERKNS_8String16E(sensorMgr, &string);
_ZN7android8String16D1Ev(&string);
}
/*
* FUNCTION: android::SensorManager::createEventQueue(void)
* USE: INTERPOSE: create an event queue to receive events
* NOTES: This function no longer exists in M, instead now one must pass
* in a client name as a "string8" and an integer "mode"to it. M
* sources list default values for these params as an empty string
* and 0. So we'll craft the same call here.
*/
void _ZN7android13SensorManager16createEventQueueEv(void **retVal, void *sensorMgr)
{
void *string;
_ZN7android7String8C1EPKc(&string, "");
_ZN7android13SensorManager16createEventQueueENS_7String8Ei(retVal, sensorMgr, &string, 0);
_ZN7android7String8D1Ev(&string);
}
/*
* FUNCTION: libEvtUnloading()
* USE: Handle library unloading
* NOTES: This is a good time to free whatever is unfreed and say goodbye
*/
void libEvtUnloading(void)
{
if (_ZN7android9SingletonINS_13SensorManagerEE9sInstanceE) {
//if an instance stil exists, free it by calling the destructor, just to be throrough
_ZN7android13SensorManagerD1Ev(_ZN7android9SingletonINS_13SensorManagerEE9sInstanceE);
_ZN7android9SingletonINS_13SensorManagerEE9sInstanceE = NULL;
}
}
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