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Commit 45024c67 authored by Aaron Okano's avatar Aaron Okano
Browse files

binder: Add Java bindings for setInheritRt 

This change adds Java functions for two features:

1. A wrapper for setInheritRt, which is available in libbinder but was
   previously not exposed to Java code.
2. A wrapper for setGlobalInheritRt to enable setInheritRt across all
   Binder instances within a process.

Flag: android.server.allow_system_server_inherit_rt
bug: 397169625
Change-Id: I2689dcd742f7bb1db74871dda0f491aceae713f0
parent bc15153a

core/java/android/os/Binder.java

+20 −0
Original line number Diff line number Diff line
@@ -1259,6 +1259,26 @@ public class Binder implements IBinder { 


    private final native void setExtensionNative(@Nullable IBinder extension);



    /**

     * Set whether or not this binder node will inherit real-time priority.

     * This should be called immediately when the object is created.

     *

     * @hide

     */

    public final native void setInheritRt(boolean inheritRt);



    /**

     * Set default RT inheritance for Binders in this process

     *

     * Any binder objects sent out of the process before this is called will

     * not use the updated value. Can be overridden by setInheritRt. Defaults

     * to false if this function is not called.

     *

     * @hide

     */

    @CriticalNative

    public static final native void setGlobalInheritRt(boolean enabled);



    /**

     * Default implementation rewinds the parcels and calls onTransact. On

     * the remote side, transact calls into the binder to do the IPC.

core/jni/android_util_Binder.cpp

+25 −0
Original line number Diff line number Diff line
@@ -496,6 +496,9 @@ public: 
                    b.get()->setExtension(extensionFromJava);

                }

            }

            if (mInheritRt) {

                b.get()->setInheritRt(mInheritRt);

            }

            mBinder = b;

            ALOGV("Creating JavaBinder %p (refs %p) for Object %p, weakCount=%" PRId32 "\n",

                 b.get(), b->getWeakRefs(), obj, b->getWeakRefs()->getWeakCount());
@@ -529,6 +532,15 @@ public: 
        }

    }



    void setInheritRt(bool inheritRt) {

        AutoMutex _l(mLock);

        mInheritRt = inheritRt;

        sp<JavaBBinder> b = mBinder.promote();

        if (b != nullptr) {

            b.get()->setInheritRt(inheritRt);

        }

    }



private:

    Mutex           mLock;

    wp<JavaBBinder> mBinder;
@@ -538,6 +550,7 @@ private: 
    // sp here (avoid recreating it)

    bool            mVintf = false;

    bool            mSetExtensionCalled = false;

    bool            mInheritRt = false;

};



// ----------------------------------------------------------------------------
@@ -1262,6 +1275,15 @@ static void android_os_Binder_setExtension(JNIEnv* env, jobject obj, jobject ext 
    jbh->setExtension(extension);

}



static void android_os_Binder_setInheritRt(JNIEnv* env, jobject obj, jboolean inheritRt) {

    JavaBBinderHolder* jbh = (JavaBBinderHolder*) env->GetLongField(obj, gBinderOffsets.mObject);

    jbh->setInheritRt(inheritRt);

}



static void android_os_Binder_setGlobalInheritRt(CRITICAL_JNI_PARAMS_COMMA jboolean enabled) {

    BBinder::setGlobalInheritRt(enabled);

}



// ----------------------------------------------------------------------------



// clang-format off
@@ -1290,6 +1312,8 @@ static const JNINativeMethod gBinderMethods[] = { 
    { "getCallingWorkSourceUid", "()I", (void*)android_os_Binder_getCallingWorkSourceUid },

    // @CriticalNative

    { "clearCallingWorkSource", "()J", (void*)android_os_Binder_clearCallingWorkSource },

    // @CriticalNative

    { "setGlobalInheritRt", "(Z)V", (void*)android_os_Binder_setGlobalInheritRt },

    { "restoreCallingWorkSource", "(J)V", (void*)android_os_Binder_restoreCallingWorkSource },

    { "markVintfStability", "()V", (void*)android_os_Binder_markVintfStability},

    { "forceDowngradeToSystemStability", "()V", (void*)android_os_Binder_forceDowngradeToSystemStability},
@@ -1298,6 +1322,7 @@ static const JNINativeMethod gBinderMethods[] = { 
    { "getNativeFinalizer", "()J", (void*)android_os_Binder_getNativeFinalizer },

    { "blockUntilThreadAvailable", "()V", (void*)android_os_Binder_blockUntilThreadAvailable },

    { "setExtensionNative", "(Landroid/os/IBinder;)V", (void*)android_os_Binder_setExtension },

    { "setInheritRt", "(Z)V", (void*)android_os_Binder_setInheritRt },

};

// clang-format on