Framework层：

    @Override
    public StackInfo getStackInfo(int stackId) {
        final int callingUid = Binder.getCallingUid();　// 拿到调用者身份
        if (callingUid != 0 && callingUid != Process.SYSTEM_UID) {
            // TODO
        }

        long ident = Binder.clearCallingIdentity(); // 转调用身份为android
        try {
            // TODO
        } finally {
            Binder.restoreCallingIdentity(ident);// 做完事之后，恢复调用者身份
        }
    }

Android 跨进程调用忽略权限