https://blog.csdn.net/aggresss/article/details/54323034
现在很多的应用都是基于位置服务的，而且把位置服务作为重要的参考标准，其实这是很不安全的，位置信息的数据未经过任何加密，而且是从我们的手机中发送出去的，所以是可以修改的。这一期我们来探讨一下如何修改手机中的定位信息。太基础的原理我就不多说了，可以参考前几期文章。
先整理一下思路，Android在开发者模式下有一个"允许模拟位置选项"，它是location service加载 MOCK location provider 实现的，通过这种线程注入的方式修改GPS信息是hacker们最喜欢的方式，但现在很多应用已经可以检测到这种注入方式而被屏蔽掉，也就是说如果我们只在APP层面上想解决方法总是有被检测出来的可能。那我们就得把问题往深了想，通过修改最底层的GPS数据来欺骗APP，在Framework层面上没有任何修改迹象，这样基于APP层面的检测机制就拿我们没有任何办法。
思路确定后我们来探讨实践路线，首先我们要建立一个管道，让我们想要定位的GPS数据提交到Android操作系统的最底层，也就是Linux Kernel层面；然后我们要修改 GPS的 location report 机制，让它从内核中提取到我们的数据，然后逐层上报到APP层。有点明修栈道暗度陈仓的感觉。
总体来说分成两部实现：1.建立到系统内核的数据管道；2.修改GPS上报机制。
这次实验使用的是闲置的小米3W手机，编译源码采用CyanogenMod-13，具体的编译环境搭建和编译方法请参考前几期文章。
因为Android系统从内核态到APP层要经过很多的层次，所以对于建立数据管道的步骤比较繁琐，我这里分成了5个步骤，对应5个层面来实现，每一步分别对应Android的 Kernel driver，HAL，JNI，Framework，Application。所有的代码我都已上传github中https://github.com/aggresss/PHDemo/ 这一期的代码在VirtualPosition 目录下。
下面描述一下实践步骤：
=============分割线1==============
第一步，修改Kernel driver
进入 kernel/xiaomi/cancro/drivers 目录下，新建vp.h文件
#ifndef _VP_ANDROID_H_
#define _VP_ANDROID_H_
#include <linux/cdev.h>
#include <linux/semaphore.h>
#define VP_DEVICE_NODE_NAME "vp"
#define VP_DEVICE_FILE_NAME "vp"
#define VP_DEVICE_PROC_NAME "vp"
#define VP_DEVICE_CLASS_NAME "vp"
typedef struct {
int toggle;
double virtual_latitude;
double virtual_longitude;
} VirtualPosition;
struct vp_android_dev {
int lamp;
VirtualPosition val;
struct semaphore sem;
struct cdev dev;
};
#endif
新建vp.c文件
/*******************************************
*include file and define functions
*******************************************/
#include <linux/init.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/fs.h>
#include <linux/proc_fs.h>
#include <linux/device.h>
#include <asm/uaccess.h>
#include "vp.h"
/*主设备和从设备号变量*/
static int vp_major = 0;
static int vp_minor = 0;
/*设备类别和设备变量*/
static struct class* vp_class = NULL;
static struct vp_android_dev* vp_dev = NULL;
/*传统的设备文件操作方法*/
static int vp_open(struct inode* inode, struct file* filp);
static int vp_release(struct inode* inode, struct file* filp);
static ssize_t vp_read(struct file* filp, char __user *buf, size_t count, loff_t* f_pos);
static ssize_t vp_write(struct file* filp, const char __user *buf, size_t count, loff_t* f_pos);
/*设备文件操作方法表*/
static struct file_operations vp_fops = {
.owner = THIS_MODULE,
.open = vp_open,
.release = vp_release,
.read = vp_read,
.write = vp_write,
};
/*访问设置属性方法*/
static ssize_t vp_lamp_show(struct device* dev, struct device_attribute* attr, char* buf);
static ssize_t vp_lamp_store(struct device* dev, struct device_attribute* attr, const char* buf, size_t count);
/*定义设备属性*/
static DEVICE_ATTR(val, S_IRUGO | S_IWUSR, vp_lamp_show, vp_lamp_store);
/*******************************************
*define traditional file access
*******************************************/
/*打开设备方法*/
static int vp_open(struct inode* inode, struct file* filp) {
struct vp_android_dev* dev;
/*将自定义设备结构体保存在文件指针的私有数据域中，以便访问设备时拿来用*/
dev = container_of(inode->i_cdev, struct vp_android_dev, dev);
filp->private_data = dev;
return 0;
}
/*设备文件释放时调用，空实现*/
static int vp_release(struct inode* inode, struct file* filp) {
return 0;
}
/*读取设备的寄存器val的值*/
static ssize_t vp_read(struct file* filp, char __user *buf, size_t count, loff_t* f_pos) {
ssize_t err = 0;
struct vp_android_dev* dev = filp->private_data;
/*同步访问*/
if(down_interruptible(&(dev->sem))) {
return -ERESTARTSYS;
}
if(count < sizeof(dev->val)) {
goto out;
}
/*将寄存器val的值拷贝到用户提供的缓冲区*/
if(copy_to_user(buf, &(dev->val), sizeof(dev->val))) {
err = -EFAULT;
goto out;
}
err = sizeof(dev->val);
out:
up(&(dev->sem));
return err;
}
/*写设备的寄存器值val*/
static ssize_t vp_write(struct file* filp, const char __user *buf, size_t count, loff_t* f_pos) {
struct vp_android_dev* dev = filp->private_data;
ssize_t err = 0;
/*同步访问*/
if(down_interruptible(&(dev->sem))) {
return -ERESTARTSYS;
}
if(count != sizeof(dev->val)) {
goto out;
}
/*将用户提供的缓冲区的值写到设备寄存器去*/
if(copy_from_user(&(dev->val), buf, count)) {
err = -EFAULT;
goto out;
}
err = sizeof(dev->val);
out:
up(&(dev->sem));
return err;
}
/*******************************************
*define devfs access
*******************************************/
/*读取寄存器lamp的值到缓冲区buf中，内部使用*/
static ssize_t __vp_get_lamp(struct vp_android_dev* dev, char* buf) {
int lamp = 0;
/*同步访问*/
if(down_interruptible(&(dev->sem))) {
return -ERESTARTSYS;
}
lamp = dev->lamp;
up(&(dev->sem));
return snprintf(buf, PAGE_SIZE, "%d\n", lamp);
}
/*把缓冲区buf的值写到设备寄存器lamp中去，内部使用*/
static ssize_t __vp_set_lamp(struct vp_android_dev* dev, const char* buf, size_t count) {
int lamp = 0;
/*将字符串转换成数字*/
lamp = simple_strtol(buf, NULL, 10);
/*同步访问*/
if(down_interruptible(&(dev->sem))) {
return -ERESTARTSYS;
}
dev->lamp = lamp;
up(&(dev->sem));
return count;
}
/*读取设备属性lamp*/
static ssize_t vp_lamp_show(struct device* dev, struct device_attribute* attr, char* buf) {
struct vp_android_dev* hdev = (struct vp_android_dev*)dev_get_drvdata(dev);
return __vp_get_lamp(hdev, buf);
}
/*写设备属性lamp*/
static ssize_t vp_lamp_store(struct device* dev, struct device_attribute* attr, const char* buf, size_t count) {
struct vp_android_dev* hdev = (struct vp_android_dev*)dev_get_drvdata(dev);
return __vp_set_lamp(hdev, buf, count);
}
/*******************************************
*define proc access
*******************************************/
/*读取设备寄存器lamp的值，保存在page缓冲区中*/
static ssize_t vp_proc_read(char* page, char** start, off_t off, int count, int* eof, void* data) {
if(off > 0) {
*eof = 1;
return 0;
}
return __vp_get_lamp(vp_dev, page);
}
/*把缓冲区的值buff保存到设备寄存器lamp中去*/
static ssize_t vp_proc_write(struct file* filp, const char __user *buff, unsigned long len, void* data) {
int err = 0;
char* page = NULL;
if(len > PAGE_SIZE) {
printk(KERN_ALERT"The buff is too large: %lu.\n", len);
return -EFAULT;
}
page = (char*)__get_free_page(GFP_KERNEL);
if(!page) {
printk(KERN_ALERT"Failed to alloc page.\n");
return -ENOMEM;
}
/*先把用户提供的缓冲区值拷贝到内核缓冲区中去*/
if(copy_from_user(page, buff, len)) {
printk(KERN_ALERT"Failed to copy buff from user.\n");
err = -EFAULT;
goto out;
}
err = __vp_set_lamp(vp_dev, page, len);
out:
free_page((unsigned long)page);
return err;
}
/*创建/proc/vp文件*/
static void vp_create_proc(void) {
struct proc_dir_entry *entry;
entry = create_proc_entry(VP_DEVICE_PROC_NAME, 0, NULL);
if(entry)
{
entry->read_proc = vp_proc_read;
entry->write_proc = vp_proc_write;
}
}
/*删除/proc/vp文件*/
static void vp_remove_proc(void) {
remove_proc_entry(VP_DEVICE_PROC_NAME, NULL);
}
/*******************************************
*define load and remove function
*******************************************/
/*初始化设备*/
static int __vp_setup_dev(struct vp_android_dev* dev) {
int err;
dev_t devno = MKDEV(vp_major, vp_minor);
memset(dev, 0, sizeof(struct vp_android_dev));
cdev_init(&(dev->dev), &vp_fops);
dev->dev.owner = THIS_MODULE;
dev->dev.ops = &vp_fops;
/*注册字符设备*/
err = cdev_add(&(dev->dev),devno, 1);
if(err) {
return err;
}
/*初始化信号量和寄存器lamp, val的值*/
sema_init(&(dev->sem), 1);
dev->lamp = 7777;
dev->val.toggle = 1;
dev->val.virtual_latitude = 45.104108;
dev->val.virtual_longitude = 130.816878;
return 0;
}
/*模块加载方法*/
static int __init vp_init(void){
int err = -1;
dev_t dev = 0;
struct device* temp = NULL;
printk(KERN_ALERT"Initializing vp device.\n");
/*动态分配主设备和从设备号*/
err = alloc_chrdev_region(&dev, 0, 1, VP_DEVICE_NODE_NAME);
if(err < 0) {
printk(KERN_ALERT"Failed to alloc char dev region.\n");
goto fail;
}
vp_major = MAJOR(dev);
vp_minor = MINOR(dev);
/*分配helo设备结构体变量*/
vp_dev = kmalloc(sizeof(struct vp_android_dev), GFP_KERNEL);
if(!vp_dev) {
err = -ENOMEM;
printk(KERN_ALERT"Failed to alloc vp_dev.\n");
goto unregister;
}
/*初始化设备*/
err = __vp_setup_dev(vp_dev);
if(err) {
printk(KERN_ALERT"Failed to setup dev: %d.\n", err);
goto cleanup;
}
/*在/sys/class/目录下创建设备类别目录vp*/
vp_class = class_create(THIS_MODULE, VP_DEVICE_CLASS_NAME);
if(IS_ERR(vp_class)) {
err = PTR_ERR(vp_class);
printk(KERN_ALERT"Failed to create vp class.\n");
goto destroy_cdev;
}
/*在/dev/目录和/sys/class/vp目录下分别创建设备文件vp*/
temp = device_create(vp_class, NULL, dev, "%s", VP_DEVICE_FILE_NAME);
if(IS_ERR(temp)) {
err = PTR_ERR(temp);
printk(KERN_ALERT"Failed to create vp device.");
goto destroy_class;
}
/*在/sys/class/vp/vp目录下创建属性文件val*/
err = device_create_file(temp, &dev_attr_val);
if(err < 0) {
printk(KERN_ALERT"Failed to create attribute val.");
goto destroy_device;
}
dev_set_drvdata(temp, vp_dev);
/*创建/proc/vp文件*/
vp_create_proc();
printk(KERN_ALERT"Succedded to initialize vp device.\n");
return 0;
destroy_device:
device_destroy(vp_class, dev);
destroy_class:
class_destroy(vp_class);
destroy_cdev:
cdev_del(&(vp_dev->dev));
cleanup:
kfree(vp_dev);
unregister:
unregister_chrdev_region(MKDEV(vp_major, vp_minor), 1);
fail:
return err;
}
/*模块卸载方法*/
static void __exit vp_exit(void) {
dev_t devno = MKDEV(vp_major, vp_minor);
printk(KERN_ALERT"Destroy vp device.\n");
/*删除/proc/vp文件*/
vp_remove_proc();
/*销毁设备类别和设备*/
if(vp_class) {
device_destroy(vp_class, MKDEV(vp_major, vp_minor));
class_destroy(vp_class);
}
/*删除字符设备和释放设备内存*/
if(vp_dev) {
cdev_del(&(vp_dev->dev));
kfree(vp_dev);
}
/*释放设备号*/
unregister_chrdev_region(devno, 1);
}
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Virtualposition Driver");
module_init(vp_init);
module_exit(vp_exit);
添加 Kconfig 文件
config VP
tristate "Virtual Position Driver"
default n
help
This is the virtual position driver.
添加 Makefile 文件
obj-$(CONFIG_VP) += vp.o
修改 drivers/Kconfig 文件 在menu "Device Drivers"和endmenu之间添加一行：
source "drivers/vp/Kconfig"
修改drivers/Makefile文件，添加一行：
obj-$(CONFIG_HELLO) += vp/
修改 arch/arm/configs目录下的cyanogen_cancro_defconfig 文件，在文件末尾加入
# CONFIG_VP
CONFIG_VP=y=============分割线2==============
第二步，修改HAL
进入 ./hardware/libhardware/include/hardware 目录，新建 vp.h 文件
#ifndef ANDROID_VP_INTERFACE_H
#define ANDROID_VP_INTERFACE_H
#include <hardware/hardware.h>
__BEGIN_DECLS
/*定义模块ID*/
#define VP_HARDWARE_MODULE_ID "vp"
//typedef enum{false, true} bool;
/*define virtual position structrue*/
typedef struct {
int toggle;
double virtual_latitude;
double virtual_longitude;
} VirtualPosition;
/*硬件模块结构体*/
struct vp_module_t {
struct hw_module_t common;
};
/*硬件接口结构体*/
struct vp_device_t {
struct hw_device_t common;
int fd;
int (*set_val)(struct vp_device_t* dev, VirtualPosition val);
int (*get_val)(struct vp_device_t* dev, VirtualPosition* val);
};
__END_DECLS
#endif
进入到 hardware/libhardware/modules 目录，新建vp目录，并添加vp.c文件
#define LOG_TAG "VpStub"
#include <hardware/hardware.h>
#include <hardware/vp.h>
#include <fcntl.h>
#include <errno.h>
#include <cutils/log.h>
#include <cutils/atomic.h>
#define DEVICE_NAME "/dev/vp"
#define MODULE_NAME "Vp"
#define MODULE_AUTHOR "[email protected]"
/*设备打开和关闭接口*/
static int vp_device_open(const struct hw_module_t* module, const char* name, struct hw_device_t** device);
static int vp_device_close(struct hw_device_t* device);
/*设备访问接口*/
static int vp_set_val(struct vp_device_t* dev, VirtualPosition val);
static int vp_get_val(struct vp_device_t* dev, VirtualPosition* val);
/*模块方法表*/
static struct hw_module_methods_t vp_module_methods = {
open: vp_device_open
};
/*模块实例变量*/
struct vp_module_t HAL_MODULE_INFO_SYM = {
common: {
tag: HARDWARE_MODULE_TAG,
version_major: 1,
version_minor: 0,
id: VP_HARDWARE_MODULE_ID,
name: MODULE_NAME,
author: MODULE_AUTHOR,
methods: &vp_module_methods,
}
};
static int vp_device_open(const struct hw_module_t* module, const char* name, struct hw_device_t** device) {
struct vp_device_t* dev;dev = (struct vp_device_t*)malloc(sizeof(struct vp_device_t));
if(!dev) {
ALOGE("Vp Stub: failed to alloc space");
return -EFAULT;
}
memset(dev, 0, sizeof(struct vp_device_t));
dev->common.tag = HARDWARE_DEVICE_TAG;
dev->common.version = 0;
dev->common.module = (hw_module_t*)module;
dev->common.close = vp_device_close;
dev->set_val = vp_set_val;dev->get_val = vp_get_val;
if((dev->fd = open(DEVICE_NAME, O_RDWR)) == -1) {
ALOGE("Vp Stub: failed to open /dev/vp -- %s.", strerror(errno));free(dev);
return -EFAULT;
}
*device = &(dev->common);
ALOGI("Vp Stub: open /dev/vp successfully.");
return 0;
}
static int vp_device_close(struct hw_device_t* device) {
struct vp_device_t* vp_device = (struct vp_device_t*)device;
if(vp_device) {
close(vp_device->fd);
free(vp_device);
}
return 0;
}
static int vp_set_val(struct vp_device_t* dev, VirtualPosition val) {
ALOGI("Vp Stub: set value %d to device.", val);
write(dev->fd, &val, sizeof(val));
return 0;
}
static int vp_get_val(struct vp_device_t* dev, VirtualPosition* val) {
if(!val) {
ALOGE("Vp Stub: error val pointer");
return -EFAULT;
}
read(dev->fd, val, sizeof(*val));
ALOGI("Vp Stub: get value %d from device", *val);
return 0;
}
继续在vp目录下新建Android.mk文件：
LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
LOCAL_MODULE_TAGS := optional
LOCAL_PRELINK_MODULE := false
LOCAL_MODULE_PATH := $(TARGET_OUT_SHARED_LIBRARIES)/hw
LOCAL_SHARED_LIBRARIES := liblog
LOCAL_SRC_FILES := vp.c
LOCAL_MODULE := vp.default
include $(BUILD_SHARED_LIBRARY)=============分割线3==============
第三步，修改JNI
进入 frameworks/base/services/core/jni 目录，新建com_android_server_VirtualPositionService.cpp文件
#define LOG_TAG "VirtualPositionService"
#include "jni.h"
#include "JNIHelp.h"
#include "android_runtime/AndroidRuntime.h"
#include <utils/misc.h>
#include <utils/Log.h>
#include <hardware/hardware.h>
#include <hardware/vp.h>
#include <stdio.h>
namespace android
{
VirtualPosition virtual_position = {1, 0.0, 0.0};
/*在硬件抽象层中定义的硬件访问结构体，参考<hardware/vp.h>*/
struct vp_device_t* vp_device = NULL;
/*通过硬件抽象层定义的硬件访问接口设置硬件寄存器val的值*/
static void vp_setVal() {
ALOGI("VirtualPosition JNI: set value to device.");
if(!vp_device) {
ALOGI("VirtualPosition JNI: device is not open.");
return;
}
vp_device->set_val(vp_device, virtual_position);
}
/*通过硬件抽象层定义的硬件访问接口读取硬件寄存器val的值*/
static void vp_getVal() {
if(!vp_device) {
ALOGI("VirtualPosition JNI: device is not open.");
}
vp_device->get_val(vp_device, &virtual_position);
ALOGI("VirtualPosition JNI: get value from device.");
}
/*通过硬件抽象层定义的硬件模块打开接口打开硬件设备*/
static inline int vp_device_open(const hw_module_t* module, struct vp_device_t** device) {
return module->methods->open(module, VP_HARDWARE_MODULE_ID, (struct hw_device_t**)device);
}
/*通过硬件模块ID来加载指定的硬件抽象层模块并打开硬件*/
static jboolean vp_init(JNIEnv* env, jclass clazz) {
vp_module_t* module;
ALOGI("VirtualPosition JNI: initializing......");
if(hw_get_module(VP_HARDWARE_MODULE_ID, (const struct hw_module_t**)&module) == 0) {
ALOGI("VirtualPosition JNI: vp Stub found.");
if(vp_device_open(&(module->common), &vp_device) == 0) {
ALOGI("VirtualPosition JNI: vp device is open.");
return 0;
}
ALOGE("VirtualPosition JNI: failed to open vp device.");
return -1;
}
ALOGE("VirtualPosition JNI: failed to get vp stub module.");
return -1;
}
static void android_server_VirtualPositionService_set_virtual_toggle(JNIEnv* env, jclass clazz, jint tog)
{
virtual_position.toggle = tog;
vp_setVal();
}
static jint android_server_VirtualPositionService_get_virtual_toggle(JNIEnv* env, jclass clazz)
{
vp_getVal();
return virtual_position.toggle;
}
static void android_server_VirtualPositionService_set_virtual_latitude(JNIEnv* env, jclass clazz, jdouble vlat)
{
virtual_position.virtual_latitude = vlat;
vp_setVal();
}
static jdouble android_server_VirtualPositionService_get_virtual_latitude(JNIEnv* env, jclass clazz)
{
vp_getVal();
return virtual_position.virtual_latitude;
}
static void android_server_VirtualPositionService_set_virtual_longitude(JNIEnv* env, jclass clazz, jdouble vlon)
{
virtual_position.virtual_longitude = vlon;
vp_setVal();
}
static jdouble android_server_VirtualPositionService_get_virtual_longitude(JNIEnv* env, jclass clazz)
{
vp_getVal();
return virtual_position.virtual_longitude;
}
/*JNI方法表*/
static const JNINativeMethod method_table[] = {
{"init_native",
"()Z",
(void*)vp_init},
{"native_set_virtual_toggle",
"(I)V",
(void*)android_server_VirtualPositionService_set_virtual_toggle},
{"native_get_virtual_toggle",
"()I",
(void*)android_server_VirtualPositionService_get_virtual_toggle},
{"native_set_virtual_latitude",
"(D)V",
(void*)android_server_VirtualPositionService_set_virtual_latitude},
{"native_get_virtual_latitude",
"()D",
(void*)android_server_VirtualPositionService_get_virtual_latitude},
{"native_set_virtual_longitude",
"(D)V",
(void*)android_server_VirtualPositionService_set_virtual_longitude},
{"native_get_virtual_longitude",
"()D",
(void*)android_server_VirtualPositionService_get_virtual_longitude},
};
/*注册JNI方法*/
int register_android_server_VirtualPositionService(JNIEnv *env) {
return jniRegisterNativeMethods(env, "com/android/server/VirtualPositionService", method_table, NELEM(method_table));
}
};
修改同目录下的onload.cpp文件，首先在namespace android增加com_android_server_VirtualPositionService函数声明：
namespace android {
..............................................................................................
int register_android_server_VirtualPositionService(JNIEnv *env);
};
在JNI_onLoad增加register_android_server_VirtualPositionService函数调用：
extern "C" jint JNI_onLoad(JavaVM* vm, void* reserved)
{
.................................................................................................
register_android_server_VirtualPositionService(env);
.................................................................................................
}
修改同目录下的Android.mk文件，在LOCAL_SRC_FILES变量中增加一行：
LOCAL_SRC_FILES:= \
com_android_server_AlarmManagerService.cpp \
com_android_server_BatteryService.cpp \
com_android_server_InputManager.cpp \
com_android_server_LightsService.cpp \
com_android_server_PowerManagerService.cpp \
com_android_server_SystemServer.cpp \
com_android_server_UsbService.cpp \
com_android_server_VibratorService.cpp \
com_android_server_location_GpsLocationProvider.cpp \
com_android_server_VirtualPositionService.cpp \
onload.cpp =============分割线4==============
第四步，修改Framework
进入到frameworks/base/core/java/android/os目录，新增VirtualPositionService.aidl接口定义文件
package android.os;
interface IVirtualPositionService {
void setVirtualToggle(int tog);
int getVirtualToggle();
void setVirtualLatitude(double vlat);
double getVirtualLatitude();
void setVirtualLongitude(double vlon);
double getVirtualLongitude();
}
然后进入 frameworks/base目录，打开Android.mk文件，修改LOCAL_SRC_FILES变量的值，增加IVirtualPosition.aidl源文件：
LOCAL_SRC_FILES += /
....................................................................
core/java/android/os/IVibratorService.aidl /
core/java/android/os/IVirtualPosition.aidl /
core/java/android/service/urlrenderer/IUrlRendererService.aidl /
.....................................................................
进入到frameworks/base/services/java/com/android/server目录，新增VirtualPositionService.java文件
package com.android.server;
import android.content.Context;
import android.os.IVirtualPositionService;
import android.util.Slog;
public class VirtualPositionService extends IVirtualPositionService.Stub {
private static final String TAG = "VirtualPositionService";
VirtualPositionService() {
init_native();
}
public void setVirtualToggle(int tog) {
native_set_virtual_toggle(tog);
}
public int getVirtualToggle(){
return native_get_virtual_toggle();
}
public void setVirtualLatitude(double vlat) {
native_set_virtual_latitude(vlat);
}
public double getVirtualLatitude(){
return native_get_virtual_latitude();
}
public void setVirtualLongitude(double vlon) {
native_set_virtual_longitude(vlon);
}
public double getVirtualLongitude() {
return native_get_virtual_longitude();
}
private static native boolean init_native();
private static native void native_set_virtual_toggle(int tog);
private static native int native_get_virtual_toggle();
private static native void native_set_virtual_latitude(double vlat);
private static native double native_get_virtual_latitude();
private static native void native_set_virtual_longitude(double vlon);
private static native double native_get_virtual_longitude();
};
修改同目录的SystemServer.java文件，在ServerThread::run函数中增加加载VirtualPositionService的代码：
@Override
public void run() {
....................................................................................
try {
Slog.i(TAG, "DiskStats Service");
ServiceManager.addService("diskstats", new DiskStatsService(context));
} catch (Throwable e) {
Slog.e(TAG, "Failure starting DiskStats Service", e);
}
try {
Slog.i(TAG, "VirtualPosition Service");
ServiceManager.addService("virtualposition", new VirtualPositionService());
} catch (Throwable e) {
Slog.e(TAG, "Failure starting VirtualPosition Service", e);
}
......................................................................................
}
然后需要修改sepolicy文件，具体的文件在github上，请下载使用。
=============分割线5==============
第五步，修改application
APP的文件比较多，请到github上下载，这里只贴具体的逻辑代码：
package com.example.phdemo.myapplication;
import android.os.RemoteException;
import android.app.Activity;
import android.os.ServiceManager;
import android.os.Bundle;
import android.widget.CompoundButton;
import android.os.IVirtualPositionService;
import android.os.RemoteException;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ToggleButton;
import android.widget.CompoundButton.OnCheckedChangeListener;
public class MainActivity extends Activity implements View.OnClickListener {
private final static String LOG_TAG = "com.example.phdemo.virtualposition";
private IVirtualPositionService virtualpositionService = null;
private ToggleButton toggleButton = null;
private EditText altitudeValueText = null;
private EditText longitudeValueText = null;
private Button getButton = null;
private Button setButton = null;
private Button clearButton = null;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
virtualpositionService = IVirtualPositionService.Stub.asInterface(
ServiceManager.getService("virtualposition"));
toggleButton=(ToggleButton)findViewById(R.id.toggleButton);
altitudeValueText = (EditText)findViewById(R.id.altitude_value);
longitudeValueText = (EditText)findViewById(R.id.longitude_value);
getButton = (Button)findViewById(R.id.button_get);
setButton = (Button)findViewById(R.id.button_set);
clearButton = (Button)findViewById(R.id.button_clear);
getButton.setOnClickListener(this);
setButton.setOnClickListener(this);
clearButton.setOnClickListener(this);
try{
int val_tog = virtualpositionService.getVirtualToggle();
if(val_tog == 1){
toggleButton.setChecked(true);
}else{
toggleButton.setChecked(false);
}
} catch (Exception e) {}
toggleButton.setOnCheckedChangeListener(new OnCheckedChangeListener(){
public void onCheckedChanged(CompoundButton buttonView,boolean isChecked) {
toggleButton.setChecked(isChecked);
try{
virtualpositionService.setVirtualToggle(isChecked?1:0);
}catch(Exception e){}
}
});
Log.i(LOG_TAG, "VirtualPosition Activity Created");
}
@Override
public void onClick(View v) {
if(v.equals(getButton)) {
try {
double val_altitude = virtualpositionService.getVirtualLatitude();
String text_altitude = String.valueOf(val_altitude);
altitudeValueText.setText(text_altitude);
double val_longitude = virtualpositionService.getVirtualLongitude();
String text_longitude = String.valueOf(val_longitude);
longitudeValueText.setText(text_longitude);
int val_tog = virtualpositionService.getVirtualToggle();
if(val_tog == 1){
toggleButton.setChecked(true);
}else{
toggleButton.setChecked(false);
}
} catch (Exception e) {
Log.e(LOG_TAG, "Remote Exception while reading value from GpsLocationProvider.");
}
}
else if(v.equals(setButton)) {
try {
String text_altitude = altitudeValueText.getText().toString();
String text_longitude = longitudeValueText.getText().toString();
double val_altitude = Double.parseDouble(text_altitude);
double val_longitude = Double.parseDouble(text_longitude);
virtualpositionService.setVirtualLatitude(val_altitude);
virtualpositionService.setVirtualLongitude(val_longitude);
} catch (Exception e) {
Log.e(LOG_TAG, "Remote Exception while writing value to GpsLocationProvider.");
}
}
else if(v.equals(clearButton)) {
String text = "";
altitudeValueText.setText(text);
longitudeValueText.setText(text);
}
}
}=============分割线6==============
最后一步，在JNI层面修改location report 机制。
进入 frameworks/base/services/core/jni 目录，修改com_android_server_location_GpsLocationProvider.cpp文件：
在全局变量部分加入
// add by aggresss
static int vp_fd = open("/dev/vp", O_RDWR);
static VirtualPosition vp_val;
修改location_callback函数：
static void location_callback(GpsLocation* location)
{
JNIEnv* env = AndroidRuntime::getJNIEnv();
//add by aggresss
read(vp_fd, &vp_val, sizeof(VirtualPosition));
if(vp_val.toggle == 1){
env->CallVoidMethod(mCallbacksObj, method_reportLocation, location->flags,
(jdouble)vp_val.virtual_latitude, (jdouble)vp_val.virtual_longitude,
(jdouble)location->altitude,
(jfloat)location->speed, (jfloat)location->bearing,
(jfloat)location->accuracy, (jlong)location->timestamp);
checkAndClearExceptionFromCallback(env, __FUNCTION__);
}
else{
env->CallVoidMethod(mCallbacksObj, method_reportLocation, location->flags,
(jdouble)location->latitude, (jdouble)location->longitude,
(jdouble)location->altitude,
(jfloat)location->speed, (jfloat)location->bearing,
(jfloat)location->accuracy, (jlong)location->timestamp);
checkAndClearExceptionFromCallback(env, __FUNCTION__);
}
}=============我是完成的分割线==============
完成后，重新编译固件，开机后启动VirtualPosition的APP，设置你想要的坐标，想在哪就在哪了。
