android developer android developer - 1 year ago 88
Android Question

READ_LOGS permission on Jelly Bean (api 16)

Since Android Jelly Bean doesn't support the logs reading permission (according to this google io 2012 video and this one too ) , i would like to know if it's possible for rooted devices (or non-rooted devices) to be able to bypass this restriction and be able to read the logs.

How do i do that? Do i really need to make the app a system app, or is rooting enough?

Answer Source

You can obtain the permission on a rooted device by executing the pm grant command from your app. Probably you will have to restart the app after that for the change to take effect, though:

String pname = getPackageName();
String[] CMDLINE_GRANTPERMS = { "su", "-c", null };
if (getPackageManager().checkPermission(android.Manifest.permission.READ_LOGS, pname) != 0) {
    Log.d(TAG, "we do not have the READ_LOGS permission!");
    if (android.os.Build.VERSION.SDK_INT >= 16) {
        Log.d(TAG, "Working around JellyBeans 'feature'...");
        try {
            // format the commandline parameter
            CMDLINE_GRANTPERMS[2] = String.format("pm grant %s android.permission.READ_LOGS", pname);
            java.lang.Process p = Runtime.getRuntime().exec(CMDLINE_GRANTPERMS);
            int res = p.waitFor();
            Log.d(TAG, "exec returned: " + res);
            if (res != 0)
                throw new Exception("failed to become root");
        } catch (Exception e) {
            Log.d(TAG, "exec(): " + e);
            Toast.makeText(context, "Failed to obtain READ_LOGS permission", Toast.LENGTH_LONG).show();
} else
    Log.d(TAG, "we have the READ_LOGS permission already!");

This code should be called from your onCreate(). Once the permission is granted, no more root powers are required.

P.S: The p.waitFor() blocks on the Superuser app, delaying your app start and potentially cause an ANR.