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Commit def1b90d authored by Olivier Gaillard's avatar Olivier Gaillard
Browse files

Use the BinderProxy#TransactListener to propagate the UID. 

PropagateWorkSourceTransactListener intercepts outgoing calls and calls
Binde#setThreadWorkSource.

Also install the listener to system server to propagate the worksource
through binder calls.

Test: manual
Change-Id: I02e88c93eebdf200691dd72b79aa7648f4d85bcb
parent 510cdfc3

core/java/android/os/Binder.java

+33 −0
Original line number Diff line number Diff line
@@ -576,6 +576,39 @@ public class Binder implements IBinder { 
        void onTransactEnded(@Nullable Object session);

    }



    /**

     * Propagates the work source to binder calls executed by the system server.

     *

     * <li>By default, this listener will propagate the worksource if the outgoing call happens on

     * the same thread as the incoming binder call.

     * <li>Custom attribution can be done by calling {@link ThreadLocalWorkSourceUid#set(int)}.

     * @hide

     */

    public static class PropagateWorkSourceTransactListener implements ProxyTransactListener {

        @Override

        public Object onTransactStarted(IBinder binder, int transactionCode) {

           // Note that {@link Binder#getCallingUid()} is already set to the UID of the current

           // process when this method is called.

           //

           // We use ThreadLocalWorkSourceUid instead. It also allows feature owners to set

           // {@link ThreadLocalWorkSourceUid#set(int) manually to attribute resources to a UID.

            int uid = ThreadLocalWorkSourceUid.get();

            if (uid >= 0) {

                int originalUid = Binder.setThreadWorkSource(uid);

                return Integer.valueOf(originalUid);

            }

            return null;

        }



        @Override

        public void onTransactEnded(Object session) {

            if (session != null) {

                int uid = (int) session;

                Binder.setThreadWorkSource(uid);

            }

        }

    }



    /**

     * Sets a listener for the transact method on the proxy-side.

     *

services/core/java/com/android/server/BinderCallsStatsService.java

+9 −1
Original line number Diff line number Diff line
@@ -49,6 +49,7 @@ public class BinderCallsStatsService extends Binder { 
    private static final String PERSIST_SYS_BINDER_CALLS_DETAILED_TRACKING

            = "persist.sys.binder_calls_detailed_tracking";





    /** Listens for flag changes. */

    private static class SettingsObserver extends ContentObserver {

        private static final String SETTINGS_ENABLED_KEY = "enabled";
@@ -101,7 +102,14 @@ public class BinderCallsStatsService extends Binder { 
            final boolean enabled =

                    mParser.getBoolean(SETTINGS_ENABLED_KEY, BinderCallsStats.ENABLED_DEFAULT);

            if (mEnabled != enabled) {

                Binder.setObserver(enabled ? mBinderCallsStats : null);

                if (enabled) {

                    Binder.setObserver(mBinderCallsStats);

                    Binder.setProxyTransactListener(

                            new Binder.PropagateWorkSourceTransactListener());

                } else {

                    Binder.setObserver(null);

                    Binder.setProxyTransactListener(null);

                }

                mEnabled = enabled;

                mBinderCallsStats.reset();

            }