Read_Logs Permission on Jelly Bean (API 16)

READ_LOGS permission on Jelly Bean (api 16)

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.

So how can I see the logs in Jelly Bean?

I got the answer in this google groups thread:
https://groups.google.com/forum/?fromgroups#!searchin/android-developers/READ_LOGS/android-developers/6U4A5irWang/8xOi74KfRIYJ

the message by Mark Murphy replying to Matteo Sisti Sette (which is me).

(it doesn't seem to be possible to link to a particular message, is it?)

POWER + VOLUME_UP + VOLUME_DOWN will generate a report and a screenshot that you can send via email or upload to Drive (ridiculous you can't share it in an arbitrary way such as send via bluetooth or open as text file, but anyways).

(seems you have to hold them for a while and the action is launched when you release them)

At first I thought he was making fun of me and that would just reboot or something, but then I tried and it works.

Which permissions can be granted to rooted devices?

The command you may be thinking of is pm grant PACKAGE PERMISSION, which can be sent to an adb-connected device using adb shell pm grant PACKAGE PERMISSION.

However, only optional permissions can be granted or revoked this way. If you try to grant a permission not requested in the app's manifest, you'll get Operation not allowed: java.lang.SecurityException: Package PACKAGE has not requested permission PERMISSION. Likewise, if you try to revoke a permission not deemed optional, you'll get Operation not allowed: java.lang.SecurityException: Can't change PERMISSION. It is required by the application. Even for a rooted device or emulator.

Now, as far as what is deemed 'optional', as well as getting a list of such permissions, that's a little unclear. However, based on some experimentation, I believe these include at least the set of permissions assigned to permission group android.permission-group.DEVELOPMENT_TOOLS. You can see which these are on a running device using pm list permissions -g. On my API 19 emulator, as well as a Nexus 7 running AOSP 4.4.4, these are:

group:android.permission-group.DEVELOPMENT_TOOLS
  permission:android.permission.ACCESS_ALL_EXTERNAL_STORAGE
  permission:android.permission.SIGNAL_PERSISTENT_PROCESSES
  permission:android.permission.READ_LOGS
  permission:android.permission.SET_ALWAYS_FINISH
  permission:android.permission.WRITE_SECURE_SETTINGS
  permission:android.permission.SET_PROCESS_LIMIT
  permission:android.permission.CHANGE_CONFIGURATION
  permission:android.permission.DUMP
  permission:android.permission.SET_DEBUG_AP

If (and only if) these are declared in the manifest, then you can grant/revoke them using the above command. Note that they are not granted automatically on installation; you must issue the pm grant command. I was able to observe and confirm this by using the Settings app and seeing the reported permissions change as I granted and revoked them.

There may be other permissions that behave like this, but I haven't found them. Normal permissions like android.permission.INTERNET cannot be granted or revoked in this manner.

Addendum: Per additional question in comment section regarding pm set-permission-enforced PERMISSION: As far as I know, the only permission which currently supports this is android.permission.READ_EXTERNAL_STORAGE. I'm basing this statement on my reading of the source code, which is also consistent with my experiences using the command. The purpose of the selective enforcement setting on this permission is to allow testing of apps under pre- and post-API 19 conditions as described here.

Using LogCat on JellyBean

So outside of rooting my device, is there any way to read the LogCat output of my app on my phone directly?

Not really. You can read discussions on aLogcat bugtracker about this issue:

After doing some reading and some testing, I've found three ways to make aLogcat work, all of which use root.

More detailed discussion about READ_LOGS permission is not granted to 3rd party applications in Jelly Bean (api 16)

jelly bean search key

This has been done specifically to circumvent patent issue. This has been mostly done only in USA, where apple recently got an injunction on galaxy nexus. So all Android phones in USA will show this behavior from now on. So most of the apps in jelly bean have a on screen search button.

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