即使获得平台签名也无法读取系统文件 [英] Cannot read system files even after obtaining platform signature

问题描述

我已经构建了一个自定义的android ROM.我已经使用平台签名对应用程序进行了签名，并在清单文件中添加了android:sharedUserId="android.uid.system".我的应用程序被授予所有签名"和系统"级别的权限，但未授予对系统文件的访问权限.

I've build a custom android ROM. I've signed my application with platform signature and have added android:sharedUserId="android.uid.system" in the manifest file. My app is granted all "signature" and "system" level permission but access to system files are not granted.

    Log.w("PC", String.valueOf(checkCallingOrSelfPermission("android.permission.ACCESS_SURFACE_FLINGER")== PackageManager.PERMISSION_GRANTED)); // true
    Log.w("PC", String.valueOf(checkCallingOrSelfPermission("android.permission.READ_FRAME_BUFFER")== PackageManager.PERMISSION_GRANTED));      // true
    Log.w("PC", String.valueOf(checkCallingOrSelfPermission("android.permission.INJECT_EVENTS")== PackageManager.PERMISSION_GRANTED));          // true

    Log.w("PC", String.valueOf(new File("/dev/graphics/fb0").canRead()));                      // false
    Log.w("PC", String.valueOf(new File("/data/misc/wifi/wpa_supplicant.conf").canRead()));   // false

文件权限为:

ls -l /dev/graphics/fb0
crw-rw---- root     graphics  29,   0 2014-02-12 09:43 fb0

ls -l /data/misc/wifi/wpa_supplicant.conf
-rwxrwx--- wifi     wifi          282 2014-02-11 19:04 wpa_supplicant.conf

有什么方法可以访问这些文件?

Is there any way to get the access to these files?

推荐答案

我已经找到解决方案.除了平台签名和android:sharedUserId="android.uid.system"之外，您还需要在清单文件的<application />部分中添加android:process="system".

I've found the solution to this. Along with the platform signature and android:sharedUserId="android.uid.system" you also need to add android:process="system" in the <application /> section of the manifest file.

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