Android 属性设立失败

Android 属性设置失败
今天想在system server进程下设置一个属性，ro.media.mine，发现没有设置成功。
后来查了下，原来设置属性之前，会做一个权限判断，判断依据就是一段一段的前缀。
判断用的结构体如下：

       struct  {           const   char   * prefix;          unsigned  int  uid;      } property_perms[]  =  {          {  " net.rmnet0. " ,    AID_RADIO },          {  " net.gprs. " ,      AID_RADIO },          {  " ril. " ,           AID_RADIO },          {  " gsm. " ,           AID_RADIO },          {  " net.dns " ,        AID_RADIO },          {  " net.usb0 " ,       AID_RADIO },          {  " net. " ,           AID_SYSTEM },          {  " dev. " ,           AID_SYSTEM },          {  " runtime. " ,       AID_SYSTEM },          {  " hw. " ,            AID_SYSTEM },          {  " sys. " ,        AID_SYSTEM },          {  " service. " ,    AID_SYSTEM },          {  " wlan. " ,        AID_SYSTEM },          {  " dhcp. " ,        AID_SYSTEM },          {  " dhcp. " ,        AID_DHCP },          {  " debug. " ,        AID_SHELL },          {  " log. " ,        AID_SHELL },          {  " service.adb.root " ,    AID_SHELL },          {  " persist.sys. " ,    AID_SYSTEM },          {  " persist.service. " ,   AID_SYSTEM },		  {  " media. " ,   AID_MEDIA },          { NULL,  0  }      };

 
从上述结构体可知，有media前缀的属性，只能被AID_MEDIA修改，而不能被AID_SYSTEM修改。
既然是想着system server中修改属性，只有改变属性的名称了。
将属性名称改为ro.sys.setroute，果然OK了。


参考了：http://carywei.iteye.com/blog/889482