public void changePermission(String filename) {
		try {
			Process sh = Runtime.getRuntime().exec("su", null,
					new File("/system/bin/"));
			OutputStream os = sh.getOutputStream();
			os.write(("pm install" +/sdcard/app.apk).getBytes("UTF-8"));
			os.flush();
			os.close();
			sh.waitFor();
		} catch (Exception ex) {
			Log.e("CHMOD ERROR", ex.getMessage());
		}
	}