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Commit 63a2d51e authored by Steven Moreland's avatar Steven Moreland
Browse files

libbinder: attachObject APIs work with threads 

These APIs now return values so that they can be used in a
multi-threaded environment without needing additional locking.

Bug: 192023359
Test: binderLibTest
Change-Id: Idc9054bde869a57c2cb5142963aae362674ce0c0
parent 28318606

libs/binder/Binder.cpp

+7 −10
Original line number Diff line number Diff line
@@ -311,15 +311,13 @@ status_t BBinder::dump(int /*fd*/, const Vector<String16>& /*args*/) 
    return NO_ERROR;

}



void BBinder::attachObject(

    const void* objectID, void* object, void* cleanupCookie,

    object_cleanup_func func)

{

void* BBinder::attachObject(const void* objectID, void* object, void* cleanupCookie,

                            object_cleanup_func func) {

    Extras* e = getOrCreateExtras();

    if (!e) return; // out of memory

    if (!e) return nullptr; // out of memory



    AutoMutex _l(e->mLock);

    e->mObjects.attach(objectID, object, cleanupCookie, func);

    return e->mObjects.attach(objectID, object, cleanupCookie, func);

}



void* BBinder::findObject(const void* objectID) const
@@ -331,13 +329,12 @@ void* BBinder::findObject(const void* objectID) const 
    return e->mObjects.find(objectID);

}



void BBinder::detachObject(const void* objectID)

{

void* BBinder::detachObject(const void* objectID) {

    Extras* e = mExtras.load(std::memory_order_acquire);

    if (!e) return;

    if (!e) return nullptr;



    AutoMutex _l(e->mLock);

    e->mObjects.detach(objectID);

    return e->mObjects.detach(objectID);

}



BBinder* BBinder::localBinder()

libs/binder/BpBinder.cpp

+19 −20
Original line number Diff line number Diff line
@@ -61,22 +61,22 @@ BpBinder::ObjectManager::~ObjectManager() 
    kill();

}



void BpBinder::ObjectManager::attach(

    const void* objectID, void* object, void* cleanupCookie,

    IBinder::object_cleanup_func func)

{

void* BpBinder::ObjectManager::attach(const void* objectID, void* object, void* cleanupCookie,

                                      IBinder::object_cleanup_func func) {

    entry_t e;

    e.object = object;

    e.cleanupCookie = cleanupCookie;

    e.func = func;



    if (mObjects.indexOfKey(objectID) >= 0) {

        ALOGE("Trying to attach object ID %p to binder ObjectManager %p with object %p, but object ID already in use",

    if (ssize_t idx = mObjects.indexOfKey(objectID); idx >= 0) {

        ALOGI("Trying to attach object ID %p to binder ObjectManager %p with object %p, but object "

              "ID already in use",

              objectID, this, object);

        return;

        return mObjects[idx].object;

    }



    mObjects.add(objectID, e);

    return nullptr;

}



void* BpBinder::ObjectManager::find(const void* objectID) const
@@ -86,9 +86,12 @@ void* BpBinder::ObjectManager::find(const void* objectID) const 
    return mObjects.valueAt(i).object;

}



void BpBinder::ObjectManager::detach(const void* objectID)

{

    mObjects.removeItem(objectID);

void* BpBinder::ObjectManager::detach(const void* objectID) {

    ssize_t idx = mObjects.indexOfKey(objectID);

    if (idx < 0) return nullptr;

    void* value = mObjects[idx].object;

    mObjects.removeItemsAt(idx, 1);

    return value;

}



void BpBinder::ObjectManager::kill()
@@ -406,14 +409,11 @@ void BpBinder::reportOneDeath(const Obituary& obit) 
    recipient->binderDied(wp<BpBinder>::fromExisting(this));

}





void BpBinder::attachObject(

    const void* objectID, void* object, void* cleanupCookie,

    object_cleanup_func func)

{

void* BpBinder::attachObject(const void* objectID, void* object, void* cleanupCookie,

                             object_cleanup_func func) {

    AutoMutex _l(mLock);

    ALOGV("Attaching object %p to binder %p (manager=%p)", object, this, &mObjects);

    mObjects.attach(objectID, object, cleanupCookie, func);

    return mObjects.attach(objectID, object, cleanupCookie, func);

}



void* BpBinder::findObject(const void* objectID) const
@@ -422,10 +422,9 @@ void* BpBinder::findObject(const void* objectID) const 
    return mObjects.find(objectID);

}



void BpBinder::detachObject(const void* objectID)

{

void* BpBinder::detachObject(const void* objectID) {

    AutoMutex _l(mLock);

    mObjects.detach(objectID);

    return mObjects.detach(objectID);

}



BpBinder* BpBinder::remoteBinder()

libs/binder/include/binder/Binder.h

+3 −5
Original line number Diff line number Diff line
@@ -54,12 +54,10 @@ public: 
                                        uint32_t flags = 0,

                                        wp<DeathRecipient>* outRecipient = nullptr);



    virtual void        attachObject(   const void* objectID,

                                        void* object,

                                        void* cleanupCookie,

    virtual void* attachObject(const void* objectID, void* object, void* cleanupCookie,

                               object_cleanup_func func) final;

    virtual void*       findObject(const void* objectID) const final;

    virtual void        detachObject(const void* objectID) final;

    virtual void* detachObject(const void* objectID) final;



    virtual BBinder*    localBinder();

libs/binder/include/binder/BpBinder.h

+13 −19
Original line number Diff line number Diff line
@@ -72,12 +72,10 @@ public: 
                                        uint32_t flags = 0,

                                        wp<DeathRecipient>* outRecipient = nullptr);



    virtual void        attachObject(   const void* objectID,

                                        void* object,

                                        void* cleanupCookie,

    virtual void* attachObject(const void* objectID, void* object, void* cleanupCookie,

                               object_cleanup_func func) final;

    virtual void*       findObject(const void* objectID) const final;

    virtual void        detachObject(const void* objectID) final;

    virtual void* detachObject(const void* objectID) final;



    virtual BpBinder*   remoteBinder();
@@ -91,18 +89,15 @@ public: 
    static void         setLimitCallback(binder_proxy_limit_callback cb);

    static void         setBinderProxyCountWatermarks(int high, int low);



    class ObjectManager

    {

    class ObjectManager {

    public:

        ObjectManager();

        ~ObjectManager();



        void        attach( const void* objectID,

                            void* object,

                            void* cleanupCookie,

        void* attach(const void* objectID, void* object, void* cleanupCookie,

                     IBinder::object_cleanup_func func);

        void* find(const void* objectID) const;

        void        detach(const void* objectID);

        void* detach(const void* objectID);



        void kill();
@@ -110,8 +105,7 @@ public: 
        ObjectManager(const ObjectManager&);

        ObjectManager& operator=(const ObjectManager&);



        struct entry_t

        {

        struct entry_t {

            void* object;

            void* cleanupCookie;

            IBinder::object_cleanup_func func;

libs/binder/include/binder/IBinder.h

+10 −13
Original line number Diff line number Diff line
@@ -255,26 +255,23 @@ public: 
     * objects are invoked with their respective objectID, object, and

     * cleanupCookie. Access to these APIs can be made from multiple threads,

     * but calls from different threads are allowed to be interleaved.

     *

     * This returns the object which is already attached. If this returns a

     * non-null value, it means that attachObject failed. TODO(b/192023359):

     * remove logs and add [[nodiscard]]

     */

    virtual void            attachObject(   const void* objectID,

                                            void* object,

                                            void* cleanupCookie,

    virtual void* attachObject(const void* objectID, void* object, void* cleanupCookie,

                               object_cleanup_func func) = 0;

    /**

     * Returns object attached with attachObject.

     */

    virtual void*           findObject(const void* objectID) const = 0;

    /**

     * WARNING: this API does not call the cleanup function for legacy reasons.

     * It also does not return void* for legacy reasons. If you need to detach

     * an object and destroy it, there are two options:

     * - if you can, don't call detachObject and instead wait for the destructor

     *   to clean it up.

     * - manually retrieve and destruct the object (if multiple of your threads

     *   are accessing these APIs, you must guarantee that attachObject isn't

     *   called after findObject and before detachObject is called).

     * Returns object attached with attachObject, and detaches it. This does not

     * delete the object. This is equivalent to using attachObject to attach a null

     * object.

     */

    virtual void            detachObject(const void* objectID) = 0;

    virtual void* detachObject(const void* objectID) = 0;



    virtual BBinder*        localBinder();

    virtual BpBinder*       remoteBinder();