Android aosp09-结合SystemProperties，通过NotificationManagerService拦截通知

文章目录 [隐藏]

本例仍旧基于lineageos18.1(android 11, api 30)

1. NotificationManagerService

首先，NotificationManager，这里什么也没做，只看下怎么进到NMS的。
%lineage%/frameworks/base/core/java/android/app/NotificationManager.java

public void notifyAsPackage(@NonNull String targetPackage, @Nullable String tag, int id,
            @NonNull Notification notification) {
        INotificationManager service = getService();
        String sender = mContext.getPackageName();

        try {
            if (localLOGV) Log.v(TAG, sender + ": notify(" + id + ", " + notification + ")");
            service.enqueueNotificationWithTag(targetPackage, sender, tag, id,
                    fixNotification(notification), mContext.getUser().getIdentifier());
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    }

    @UnsupportedAppUsage
    public void notifyAsUser(String tag, int id, Notification notification, UserHandle user) { // 搜到的帖子都说是进入此函数
        INotificationManager service = getService(); // 这里拿到NMS
        String pkg = mContext.getPackageName();

        try {
            if (localLOGV) Log.v(TAG, pkg + ": notify(" + id + ", " + notification + ")");
            service.enqueueNotificationWithTag(pkg, mContext.getOpPackageName(), tag, id,
                    fixNotification(notification), user.getIdentifier()); // 这里调用NMS
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    }

public void notifyAsPackage(@NonNull String targetPackage, @Nullable String tag, int id,

@NonNull Notification notification) {

INotificationManager service = getService();

String sender = mContext.getPackageName();

try {

if (localLOGV) Log.v(TAG, sender + ": notify(" + id + ", " + notification + ")");

service.enqueueNotificationWithTag(targetPackage, sender, tag, id,

fixNotification(notification), mContext.getUser().getIdentifier());

} catch (RemoteException e) {

throw e.rethrowFromSystemServer();

}

@UnsupportedAppUsage

public void notifyAsUser(String tag, int id, Notification notification, UserHandle user) { // 搜到的帖子都说是进入此函数

INotificationManager service = getService(); // 这里拿到NMS

String pkg = mContext.getPackageName();

try {

if (localLOGV) Log.v(TAG, pkg + ": notify(" + id + ", " + notification + ")");

service.enqueueNotificationWithTag(pkg, mContext.getOpPackageName(), tag, id,

fixNotification(notification), user.getIdentifier()); // 这里调用NMS

} catch (RemoteException e) {

throw e.rethrowFromSystemServer();

}

然后，是NotificationManagerService，虽然还有后续各种类，姑且在这里拦截吧。
%lineage%/frameworks/base/services/core/java/com/android/server/notification/NotificationManagerService.java

public void enqueueNotificationWithTag(String pkg, String opPkg, String tag, int id,
        Notification notification, int userId) throws RemoteException {
    enqueueNotificationInternal(pkg, opPkg, Binder.getCallingUid(),
            Binder.getCallingPid(), tag, id, notification, userId);
}

void enqueueNotificationInternal(final String pkg, final String opPkg, final int callingUid,
        final int callingPid, final String tag, final int id, final Notification notification,
        int incomingUserId) {
    enqueueNotificationInternal(pkg, opPkg, callingUid, callingPid, tag, id, notification,
    incomingUserId, false);
}

void enqueueNotificationInternal(final String pkg, final String opPkg, final int callingUid,
        final int callingPid, final String tag, final int id, final Notification notification,
        int incomingUserId, boolean postSilently) {
        
        Log.i("aosp_acer", "要发送通知的pkg："+pkg);
        Log.i("aosp_acer", "要发送通知的opPkg："+opPkg);
        CharSequence title = notification.extras.getCharSequence(Notification.EXTRA_TITLE);
        CharSequence text = notification.extras.getCharSequence(Notification.EXTRA_TEXT);
        Log.i("aosp_acer", "要发送的通知title："+title);
        Log.i("aosp_acer", "要发送的通知text："+text);

        String value = SystemProperties.get(pkg, "able");  // 这里调用SystemProperties获取指定的key，这个key须要提前注册
        if("disable".equals(value)){ 
            // disable是我们自定义的表示‘禁止通知’。tts语言提示，log日志等
            return;
        }
        
        if (DBG) {
            Slog.v(TAG, "enqueueNotificationInternal: pkg=" + pkg + " id=" + id
                    + " notification=" + notification);
        }
        
        // ... 后续代码略

public void enqueueNotificationWithTag(String pkg, String opPkg, String tag, int id,

Notification notification, int userId) throws RemoteException {

enqueueNotificationInternal(pkg, opPkg, Binder.getCallingUid(),

Binder.getCallingPid(), tag, id, notification, userId);

}

void enqueueNotificationInternal(final String pkg, final String opPkg, final int callingUid,

final int callingPid, final String tag, final int id, final Notification notification,

int incomingUserId) {

enqueueNotificationInternal(pkg, opPkg, callingUid, callingPid, tag, id, notification,

incomingUserId, false);

}

void enqueueNotificationInternal(final String pkg, final String opPkg, final int callingUid,

final int callingPid, final String tag, final int id, final Notification notification,

int incomingUserId, boolean postSilently) {

Log.i("aosp_acer", "要发送通知的pkg："+pkg);

Log.i("aosp_acer", "要发送通知的opPkg："+opPkg);

CharSequence title = notification.extras.getCharSequence(Notification.EXTRA_TITLE);

CharSequence text = notification.extras.getCharSequence(Notification.EXTRA_TEXT);

Log.i("aosp_acer", "要发送的通知title："+title);

Log.i("aosp_acer", "要发送的通知text："+text);

String value = SystemProperties.get(pkg, "able"); // 这里调用SystemProperties获取指定的key，这个key须要提前注册

if("disable".equals(value)){

// disable是我们自定义的表示‘禁止通知’。tts语言提示，log日志等

return;

}

if (DBG) {

Slog.v(TAG, "enqueueNotificationInternal: pkg=" + pkg + " id=" + id

+ " notification=" + notification);

}

// ... 后续代码略

NMS的启动是在SystemServer里，
%lineage%/frameworks/base/services/java/com/android/server/SystemServer.java 中有一句


mSystemServiceManager.startService(NotificationManagerService.class);

mSystemServiceManager.startService(NotificationManagerService.class);

2. SystemProperties

要想使用SystemProperties，必须是系统权限的app，然后，它操作的key必须是经过注册的，而且注册还是有作用域的-对作用域也要注册。
先说怎么注册key：
%lineage%/system/sepolicy/private/property_contexts 插入1行

# 仿照已有的配置填写
自定义的key   u:object_r:system_prop:s0

1 2	# 仿照已有的配置填写自定义的key u:object_r:system_prop:s0

这里的“system_prop”就是作用域。SELinux权限的范畴。
同时 %lineage%/system/sepolicy/prebuilts/api/ 下有好几个以api版本数字命名的文件夹，要适配哪个版本的手机就进入哪个文件下，如本例
%lineage%/system/sepolicy/prebuilts/api/30.0/private/property_contexts ，同样的内容添加1行。

接着注册作用域：
%lineage%/system/sepolicy/private/platform_app.te 中添加1行


allow platform_app system_prop:property_service set;

allow platform_app system_prop:property_service set;

同时 %lineage%/system/sepolicy/prebuilts/api/30.0/private/platform_app.te ，同样的内容添加1行。

3. 自己开发的app

首先 AndroidManifest.xml 里 application 节点增加属性 android:sharedUserId="android.uid.system" ：

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.cuiweiyou.notificationtester">

    <application 
        android:sharedUserId="android.uid.system" >

<?xml version="1.0" encoding="utf-8"?>

<manifest xmlns:android="http://schemas.android.com/apk/res/android"

package="com.cuiweiyou.notificationtester">

<application

android:sharedUserId="android.uid.system" >

然后通过反射调用SystemProperties，但是后续既然要对app进行系统签名，所以直接引入SystemProperties使用应该也是可以的。

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

public class SystemUtil {

    private static SystemUtil instance;
    private Method methodSet;
    private Method methodGet;

    public static SystemUtil getInstance() {
        if (null == instance) {
            synchronized (SystemUtil.class) {
                if (null == instance) {
                    instance = new SystemUtil();
                }
            }
        }
        return instance;
    }

    private SystemUtil() {
        try {
            Class<?> clazz = Class.forName("android.os.SystemProperties");
            methodSet = clazz.getMethod("set", String.class, String.class);
            methodSet.setAccessible(true);

            methodGet = clazz.getMethod("get", String.class);
            methodGet.setAccessible(true);
        } catch (ClassNotFoundException | NoSuchMethodException e) {
            e.printStackTrace();
        }
    }

    public void set(String pkg, String flag) {
        try {
            methodSet.invoke(null, pkg, flag);
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (InvocationTargetException e) {
            e.printStackTrace();
        }
    }

    public String get(String pkg) {
        String flag = null;
        try {
            flag = (String) methodGet.invoke((Object) null, pkg);
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (InvocationTargetException e) {
            e.printStackTrace();
        }
        return flag;
    }
}

import java.lang.reflect.InvocationTargetException;

import java.lang.reflect.Method;

public class SystemUtil {

private static SystemUtil instance;

private Method methodSet;

private Method methodGet;

public static SystemUtil getInstance() {

if (null == instance) {

synchronized (SystemUtil.class) {

if (null == instance) {

instance = new SystemUtil();

}

return instance;

}

private SystemUtil() {

try {

Class<?> clazz = Class.forName("android.os.SystemProperties");

methodSet = clazz.getMethod("set", String.class, String.class);

methodSet.setAccessible(true);

methodGet = clazz.getMethod("get", String.class);

methodGet.setAccessible(true);

} catch (ClassNotFoundException | NoSuchMethodException e) {

e.printStackTrace();

}

public void set(String pkg, String flag) {

try {

methodSet.invoke(null, pkg, flag);

} catch (IllegalAccessException e) {

e.printStackTrace();

} catch (InvocationTargetException e) {

e.printStackTrace();

}

public String get(String pkg) {

String flag = null;

try {

flag = (String) methodGet.invoke((Object) null, pkg);

} catch (IllegalAccessException e) {

e.printStackTrace();

} catch (InvocationTargetException e) {

e.printStackTrace();

}

return flag;

}

最后，把自定义签名文件发布release的apk文件(假设文件名 mytest.apk)，放到 %lineageos%/packages/mytest/ 下，
并创建 Android.mk 文件

LOCAL_PATH:= $(call my-dir)
include $(CLEAR_VARS)
# 生成的模块名称
LOCAL_MODULE := mytest
# 生成的模块类型
LOCAL_MODULE_CLASS := APPS
# 生成的模块后缀名,此处为apk
LOCAL_MODULE_SUFFIX := $(COMMON_ANDROID_PACKAGE_SUFFIX)
# 设置模块tag，tags取值可以为:user debug eng tests optional
# optional表示全平台编译
LOCAL_MODULE_TAGS := optional
# LOCAL_PRIVILEGED_MODULE := true
LOCAL_BUILT_MODULE_STEM := package.apk
# 设置源文件
LOCAL_SRC_FILES := mytest.apk
# 设置签名，platform表示签名为系统应用
LOCAL_CERTIFICATE := platform
include $(BUILD_PREBUILT)

LOCAL_PATH:= $(call my-dir)

include $(CLEAR_VARS)

# 生成的模块名称

LOCAL_MODULE := mytest

# 生成的模块类型

LOCAL_MODULE_CLASS := APPS

# 生成的模块后缀名,此处为apk

LOCAL_MODULE_SUFFIX := $(COMMON_ANDROID_PACKAGE_SUFFIX)

# 设置模块tag，tags取值可以为:user debug eng tests optional

# optional表示全平台编译

LOCAL_MODULE_TAGS := optional

# LOCAL_PRIVILEGED_MODULE := true

LOCAL_BUILT_MODULE_STEM := package.apk

# 设置源文件

LOCAL_SRC_FILES := mytest.apk

# 设置签名，platform表示签名为系统应用

LOCAL_CERTIFICATE := platform

include $(BUILD_PREBUILT)

最最后打开 %lineage%/build/make/target/product/handheld_product.mk ，把 ‘mytest’ 加入到 PRODUCT_PACKAGES 一项里。

4. 编译系统刷机

测试后，就可以打开mytest app通过 SystemUtil.getInstance().set("自定义的key", "able"); 或者 "disable"，对这个app的通知进行控制了。

- end

声明

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