Android 修改源码，默认授予第三方APP权限，不用动态授权

android 6.0 开始引入动态权限机制，某些敏感权限需要用户手动同意后才可以使用。
作为系统APP ，无需动态申请，声明后直接使用即可。
如果第三方APP需要默认拥有某些权限，无需动态申请，该怎么做呢？
两种方法：
1.第三方APP打系统签名；
2.修改源码，默认授予第三方APP权限。

修改源码

基于AN 8.0 ，默认权限的管理在 frameworks/base/services/core/java/com/android/server/pm/DefaultPermissionGrantPolicy.java 类，首次开机会执行，我们关注grantDefaultSystemHandlerPermissions(int userId) 函数，

synchronized (mService.mPackages) {
            // Installer
            PackageParser.Package installerPackage = getSystemPackageLPr(
                    mService.mRequiredInstallerPackage);
            if (installerPackage != null
                    && doesPackageSupportRuntimePermissions(installerPackage)) {
                grantRuntimePermissionsLPw(installerPackage, STORAGE_PERMISSIONS, true, userId);
            }

            // Verifier
            PackageParser.Package verifierPackage = getSystemPackageLPr(
                    mService.mRequiredVerifierPackage);
            if (verifierPackage != null
                    && doesPackageSupportRuntimePermissions(verifierPackage)) {
                grantRuntimePermissionsLPw(verifierPackage, STORAGE_PERMISSIONS, true, userId);
                grantRuntimePermissionsLPw(verifierPackage, PHONE_PERMISSIONS, false, userId);
                grantRuntimePermissionsLPw(verifierPackage, SMS_PERMISSIONS, false, userId);
            }

            // SetupWizard
            PackageParser.Package setupPackage = getSystemPackageLPr(
                    mService.mSetupWizardPackage);
            if (setupPackage != null
                    && doesPackageSupportRuntimePermissions(setupPackage)) {
                grantRuntimePermissionsLPw(setupPackage, PHONE_PERMISSIONS, userId);
                grantRuntimePermissionsLPw(setupPackage, CONTACTS_PERMISSIONS, userId);
                grantRuntimePermissionsLPw(setupPackage, LOCATION_PERMISSIONS, userId);
                grantRuntimePermissionsLPw(setupPackage, CAMERA_PERMISSIONS, userId);
            }

            // Camera
            Intent cameraIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
            PackageParser.Package cameraPackage = getDefaultSystemHandlerActivityPackageLPr(
                    cameraIntent, userId);
            if (cameraPackage != null
                    && doesPackageSupportRuntimePermissions(cameraPackage)) {
                grantRuntimePermissionsLPw(cameraPackage, CAMERA_PERMISSIONS, userId);
                grantRuntimePermissionsLPw(cameraPackage, MICROPHONE_PERMISSIONS, userId);
                grantRuntimePermissionsLPw(cameraPackage, STORAGE_PERMISSIONS, userId);
            }
			
			//省略部分代码
			
            mService.mSettings.onDefaultRuntimePermissionsGrantedLPr(userId);
        }

以 Camera 为例，通过 grantRuntimePermissionsLPw 函数授予其相关的权限，权限的定义为

	private static final Set<String> MICROPHONE_PERMISSIONS = new ArraySet<>();
    static {
        MICROPHONE_PERMISSIONS.add(Manifest.permission.RECORD_AUDIO);
    }

    private static final Set<String> CAMERA_PERMISSIONS = new ArraySet<>();
    static {
        CAMERA_PERMISSIONS.add(Manifest.permission.CAMERA);
    }
    
    private static final Set<String> STORAGE_PERMISSIONS = new ArraySet<>();
    static {
        STORAGE_PERMISSIONS.add(Manifest.permission.READ_EXTERNAL_STORAGE);
        STORAGE_PERMISSIONS.add(Manifest.permission.WRITE_EXTERNAL_STORAGE);
    }

如此，参考 Camera ，给第三方应用授予相关权限：

private static final String MYAPPE_PKG_NAME= "com.myapp.test";

// test app
PackageParser.Package myAppPackage = getPackageLPr(MYAPPE_PKG_NAME);
	if(null != fxHomePackage
		&& doesPackageSupportRuntimePermissions(fxHomePackage)){
			grantRuntimePermissionsLPw(fxHomePackage, CAMERA_PERMISSIONS, userId);
			grantRuntimePermissionsLPw(fxHomePackage, CONTACTS_PERMISSIONS, userId);
			grantRuntimePermissionsLPw(fxHomePackage, LOCATION_PERMISSIONS, userId);
			grantRuntimePermissionsLPw(fxHomePackage, MICROPHONE_PERMISSIONS, userId);
			grantRuntimePermissionsLPw(fxHomePackage, STORAGE_PERMISSIONS, userId);
			Log.d(TAG, "Granting permissions to package com.bestv.ott");
	}

烧录后查看 /data/system/users/0/runtime-permissions.xml 文件，
通过包名查找 应用的权限授予情况，
当然，代码逻辑及功能检查更稳妥。

参考：https://blog.csdn.net/fmc088/article/details/81050520