libs/binder/IMemory.cpp - LeafOS-Project/android_frameworks_native - Gitiles

 /*
  * Copyright (C) 2008 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 #define LOG_TAG "IMemory"

 #include <atomic>
 #include <stdatomic.h>

 #include <fcntl.h>
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <sys/types.h>
 #include <sys/mman.h>
 #include <unistd.h>

 #include <binder/IMemory.h>
 #include <binder/Parcel.h>
 #include <log/log.h>

 #include <utils/KeyedVector.h>
 #include <utils/threads.h>

 #define VERBOSE   0

 namespace android {
 // ---------------------------------------------------------------------------

 class HeapCache : public IBinder::DeathRecipient
 {
 public:
     HeapCache();
     virtual ~HeapCache();

     virtual void binderDied(const wp<IBinder>& who);

     sp<IMemoryHeap> find_heap(const sp<IBinder>& binder);
     void free_heap(const sp<IBinder>& binder);
     sp<IMemoryHeap> get_heap(const sp<IBinder>& binder);
     void dump_heaps();

 private:
     // For IMemory.cpp
     struct heap_info_t {
         sp<IMemoryHeap> heap;
         int32_t         count;
         // Note that this cannot be meaningfully copied.
     };

     void free_heap(const wp<IBinder>& binder);

     Mutex mHeapCacheLock;  // Protects entire vector below.
     KeyedVector< wp<IBinder>, heap_info_t > mHeapCache;
     // We do not use the copy-on-write capabilities of KeyedVector.
     // TODO: Reimplemement based on standard C++ container?
 };

 static sp<HeapCache> gHeapCache = sp<HeapCache>::make();

 /******************************************************************************/

 enum {
     HEAP_ID = IBinder::FIRST_CALL_TRANSACTION
 };

 class BpMemoryHeap : public BpInterface<IMemoryHeap>
 {
 public:
     explicit BpMemoryHeap(const sp<IBinder>& impl);
     virtual ~BpMemoryHeap();

     int getHeapID() const override;
     void* getBase() const override;
     size_t getSize() const override;
     uint32_t getFlags() const override;
     off_t getOffset() const override;

 private:
     friend class IMemory;
     friend class HeapCache;

     // for debugging in this module
     static inline sp<IMemoryHeap> find_heap(const sp<IBinder>& binder) {
         return gHeapCache->find_heap(binder);
     }
     static inline void free_heap(const sp<IBinder>& binder) {
         gHeapCache->free_heap(binder);
     }
     static inline sp<IMemoryHeap> get_heap(const sp<IBinder>& binder) {
         return gHeapCache->get_heap(binder);
     }
     static inline void dump_heaps() {
         gHeapCache->dump_heaps();
     }

     void assertMapped() const;
     void assertReallyMapped() const;

     mutable std::atomic<int32_t> mHeapId;
     mutable void*       mBase;
     mutable size_t      mSize;
     mutable uint32_t    mFlags;
     mutable off_t       mOffset;
     mutable bool        mRealHeap;
     mutable Mutex       mLock;
 };

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

 enum {
     GET_MEMORY = IBinder::FIRST_CALL_TRANSACTION
 };

 class BpMemory : public BpInterface<IMemory>
 {
 public:
     explicit BpMemory(const sp<IBinder>& impl);
     virtual ~BpMemory();
     // NOLINTNEXTLINE(google-default-arguments)
     virtual sp<IMemoryHeap> getMemory(ssize_t* offset=nullptr, size_t* size=nullptr) const;

 private:
     mutable sp<IMemoryHeap> mHeap;
     mutable ssize_t mOffset;
     mutable size_t mSize;
 };

 /******************************************************************************/

 void* IMemory::fastPointer(const sp<IBinder>& binder, ssize_t offset) const
 {
     sp<IMemoryHeap> realHeap = BpMemoryHeap::get_heap(binder);
     void* const base = realHeap->base();
     if (base == MAP_FAILED)
         return nullptr;
     return static_cast<char*>(base) + offset;
 }

 void* IMemory::unsecurePointer() const {
     ssize_t offset;
     sp<IMemoryHeap> heap = getMemory(&offset);
     void* const base = heap!=nullptr ? heap->base() : MAP_FAILED;
     if (base == MAP_FAILED)
         return nullptr;
     return static_cast<char*>(base) + offset;
 }

 void* IMemory::pointer() const { return unsecurePointer(); }

 size_t IMemory::size() const {
     size_t size;
     getMemory(nullptr, &size);
     return size;
 }

 ssize_t IMemory::offset() const {
     ssize_t offset;
     getMemory(&offset);
     return offset;
 }

 /******************************************************************************/

 BpMemory::BpMemory(const sp<IBinder>& impl)
     : BpInterface<IMemory>(impl), mOffset(0), mSize(0)
 {
 }

 BpMemory::~BpMemory()
 {
 }

 // NOLINTNEXTLINE(google-default-arguments)
 sp<IMemoryHeap> BpMemory::getMemory(ssize_t* offset, size_t* size) const
 {
     if (mHeap == nullptr) {
         Parcel data, reply;
         data.writeInterfaceToken(IMemory::getInterfaceDescriptor());
         if (remote()->transact(GET_MEMORY, data, &reply) == NO_ERROR) {
             sp<IBinder> heap = reply.readStrongBinder();
             if (heap != nullptr) {
                 mHeap = interface_cast<IMemoryHeap>(heap);
                 if (mHeap != nullptr) {
                     const int64_t offset64 = reply.readInt64();
                     const uint64_t size64 = reply.readUint64();
                     const ssize_t o = (ssize_t)offset64;
                     const size_t s = (size_t)size64;
                     size_t heapSize = mHeap->getSize();
                     if (s == size64 && o == offset64 // ILP32 bounds check
                             && s <= heapSize
                             && o >= 0
                             && (static_cast<size_t>(o) <= heapSize - s)) {
                         mOffset = o;
                         mSize = s;
                     } else {
                         // Hm.
                         android_errorWriteWithInfoLog(0x534e4554,
                             "26877992", -1, nullptr, 0);
                         mOffset = 0;
                         mSize = 0;
                     }
                 }
             }
         }
     }
     if (offset) *offset = mOffset;
     if (size) *size = mSize;
     return (mSize > 0) ? mHeap : nullptr;
 }

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

 IMPLEMENT_META_INTERFACE(Memory, "android.utils.IMemory")

 BnMemory::BnMemory() {
 }

 BnMemory::~BnMemory() {
 }

 // NOLINTNEXTLINE(google-default-arguments)
 status_t BnMemory::onTransact(
     uint32_t code, const Parcel& data, Parcel* reply, uint32_t flags)
 {
     switch(code) {
         case GET_MEMORY: {
             CHECK_INTERFACE(IMemory, data, reply);
             ssize_t offset;
             size_t size;
             reply->writeStrongBinder( IInterface::asBinder(getMemory(&offset, &size)) );
             reply->writeInt64(offset);
             reply->writeUint64(size);
             return NO_ERROR;
         } break;
         default:
             return BBinder::onTransact(code, data, reply, flags);
     }
 }


 /******************************************************************************/

 BpMemoryHeap::BpMemoryHeap(const sp<IBinder>& impl)
     : BpInterface<IMemoryHeap>(impl),
         mHeapId(-1), mBase(MAP_FAILED), mSize(0), mFlags(0), mOffset(0), mRealHeap(false)
 {
 }

 BpMemoryHeap::~BpMemoryHeap() {
     int32_t heapId = mHeapId.load(memory_order_relaxed);
     if (heapId != -1) {
         close(heapId);
         if (mRealHeap) {
             // by construction we're the last one
             if (mBase != MAP_FAILED) {
                 sp<IBinder> binder = IInterface::asBinder(this);

                 if (VERBOSE) {
                     ALOGD("UNMAPPING binder=%p, heap=%p, size=%zu, fd=%d",
                             binder.get(), this, mSize, heapId);
                 }

                 munmap(mBase, mSize);
             }
         } else {
             // remove from list only if it was mapped before
             sp<IBinder> binder = IInterface::asBinder(this);
             free_heap(binder);
         }
     }
 }

 void BpMemoryHeap::assertMapped() const
 {
     int32_t heapId = mHeapId.load(memory_order_acquire);
     if (heapId == -1) {
         sp<IBinder> binder(IInterface::asBinder(const_cast<BpMemoryHeap*>(this)));
         sp<BpMemoryHeap> heap = sp<BpMemoryHeap>::cast(find_heap(binder));
         heap->assertReallyMapped();
         if (heap->mBase != MAP_FAILED) {
             Mutex::Autolock _l(mLock);
             if (mHeapId.load(memory_order_relaxed) == -1) {
                 mBase   = heap->mBase;
                 mSize   = heap->mSize;
                 mOffset = heap->mOffset;
                 int fd = fcntl(heap->mHeapId.load(memory_order_relaxed), F_DUPFD_CLOEXEC, 0);
                 ALOGE_IF(fd==-1, "cannot dup fd=%d",
                         heap->mHeapId.load(memory_order_relaxed));
                 mHeapId.store(fd, memory_order_release);
             }
         } else {
             // something went wrong
             free_heap(binder);
         }
     }
 }

 void BpMemoryHeap::assertReallyMapped() const
 {
     int32_t heapId = mHeapId.load(memory_order_acquire);
     if (heapId == -1) {

         // remote call without mLock held, worse case scenario, we end up
         // calling transact() from multiple threads, but that's not a problem,
         // only mmap below must be in the critical section.

         Parcel data, reply;
         data.writeInterfaceToken(IMemoryHeap::getInterfaceDescriptor());
         status_t err = remote()->transact(HEAP_ID, data, &reply);
         int parcel_fd = reply.readFileDescriptor();
         const uint64_t size64 = reply.readUint64();
         const int64_t offset64 = reply.readInt64();
         const uint32_t flags = reply.readUint32();
         const size_t size = (size_t)size64;
         const off_t offset = (off_t)offset64;
         if (err != NO_ERROR || // failed transaction
                 size != size64 || offset != offset64) { // ILP32 size check
             ALOGE("binder=%p transaction failed fd=%d, size=%zu, err=%d (%s)",
                     IInterface::asBinder(this).get(),
                     parcel_fd, size, err, strerror(-err));
             return;
         }

         Mutex::Autolock _l(mLock);
         if (mHeapId.load(memory_order_relaxed) == -1) {
             int fd = fcntl(parcel_fd, F_DUPFD_CLOEXEC, 0);
             ALOGE_IF(fd == -1, "cannot dup fd=%d, size=%zu, err=%d (%s)",
                     parcel_fd, size, err, strerror(errno));

             int access = PROT_READ;
             if (!(flags & READ_ONLY)) {
                 access |= PROT_WRITE;
             }
             mRealHeap = true;
             mBase = mmap(nullptr, size, access, MAP_SHARED, fd, offset);
             if (mBase == MAP_FAILED) {
                 ALOGE("cannot map BpMemoryHeap (binder=%p), size=%zu, fd=%d (%s)",
                         IInterface::asBinder(this).get(), size, fd, strerror(errno));
                 close(fd);
             } else {
                 mSize = size;
                 mFlags = flags;
                 mOffset = offset;
                 mHeapId.store(fd, memory_order_release);
             }
         }
     }
 }

 int BpMemoryHeap::getHeapID() const {
     assertMapped();
     // We either stored mHeapId ourselves, or loaded it with acquire semantics.
     return mHeapId.load(memory_order_relaxed);
 }

 void* BpMemoryHeap::getBase() const {
     assertMapped();
     return mBase;
 }

 size_t BpMemoryHeap::getSize() const {
     assertMapped();
     return mSize;
 }

 uint32_t BpMemoryHeap::getFlags() const {
     assertMapped();
     return mFlags;
 }

 off_t BpMemoryHeap::getOffset() const {
     assertMapped();
     return mOffset;
 }

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

 IMPLEMENT_META_INTERFACE(MemoryHeap, "android.utils.IMemoryHeap")

 BnMemoryHeap::BnMemoryHeap() {
 }

 BnMemoryHeap::~BnMemoryHeap() {
 }

 // NOLINTNEXTLINE(google-default-arguments)
 status_t BnMemoryHeap::onTransact(
         uint32_t code, const Parcel& data, Parcel* reply, uint32_t flags)
 {
     switch(code) {
        case HEAP_ID: {
             CHECK_INTERFACE(IMemoryHeap, data, reply);
             reply->writeFileDescriptor(getHeapID());
             reply->writeUint64(getSize());
             reply->writeInt64(getOffset());
             reply->writeUint32(getFlags());
             return NO_ERROR;
         } break;
         default:
             return BBinder::onTransact(code, data, reply, flags);
     }
 }

 /*****************************************************************************/

 HeapCache::HeapCache()
     : DeathRecipient()
 {
 }

 HeapCache::~HeapCache()
 {
 }

 void HeapCache::binderDied(const wp<IBinder>& binder)
 {
     //ALOGD("binderDied binder=%p", binder.unsafe_get());
     free_heap(binder);
 }

 sp<IMemoryHeap> HeapCache::find_heap(const sp<IBinder>& binder)
 {
     Mutex::Autolock _l(mHeapCacheLock);
     ssize_t i = mHeapCache.indexOfKey(binder);
     if (i>=0) {
         heap_info_t& info = mHeapCache.editValueAt(i);
         ALOGD_IF(VERBOSE,
                 "found binder=%p, heap=%p, size=%zu, fd=%d, count=%d",
                 binder.get(), info.heap.get(),
                 static_cast<BpMemoryHeap*>(info.heap.get())->mSize,
                 static_cast<BpMemoryHeap*>(info.heap.get())
                     ->mHeapId.load(memory_order_relaxed),
                 info.count);
         ++info.count;
         return info.heap;
     } else {
         heap_info_t info;
         info.heap = interface_cast<IMemoryHeap>(binder);
         info.count = 1;
         //ALOGD("adding binder=%p, heap=%p, count=%d",
         //      binder.get(), info.heap.get(), info.count);
         mHeapCache.add(binder, info);
         return info.heap;
     }
 }

 void HeapCache::free_heap(const sp<IBinder>& binder)  {
     free_heap( wp<IBinder>(binder) );
 }

 void HeapCache::free_heap(const wp<IBinder>& binder)
 {
     sp<IMemoryHeap> rel;
     {
         Mutex::Autolock _l(mHeapCacheLock);
         ssize_t i = mHeapCache.indexOfKey(binder);
         if (i>=0) {
             heap_info_t& info(mHeapCache.editValueAt(i));
             if (--info.count == 0) {
                 ALOGD_IF(VERBOSE,
                         "removing binder=%p, heap=%p, size=%zu, fd=%d, count=%d",
                         binder.unsafe_get(), info.heap.get(),
                         static_cast<BpMemoryHeap*>(info.heap.get())->mSize,
                         static_cast<BpMemoryHeap*>(info.heap.get())
                             ->mHeapId.load(memory_order_relaxed),
                         info.count);
                 rel = mHeapCache.valueAt(i).heap;
                 mHeapCache.removeItemsAt(i);
             }
         } else {
             ALOGE("free_heap binder=%p not found!!!", binder.unsafe_get());
         }
     }
 }

 sp<IMemoryHeap> HeapCache::get_heap(const sp<IBinder>& binder)
 {
     sp<IMemoryHeap> realHeap;
     Mutex::Autolock _l(mHeapCacheLock);
     ssize_t i = mHeapCache.indexOfKey(binder);
     if (i>=0)   realHeap = mHeapCache.valueAt(i).heap;
     else        realHeap = interface_cast<IMemoryHeap>(binder);
     return realHeap;
 }

 void HeapCache::dump_heaps()
 {
     Mutex::Autolock _l(mHeapCacheLock);
     int c = mHeapCache.size();
     for (int i=0 ; i<c ; i++) {
         const heap_info_t& info = mHeapCache.valueAt(i);
         BpMemoryHeap const* h(static_cast<BpMemoryHeap const *>(info.heap.get()));
         ALOGD("hey=%p, heap=%p, count=%d, (fd=%d, base=%p, size=%zu)",
                 mHeapCache.keyAt(i).unsafe_get(),
                 info.heap.get(), info.count,
                 h->mHeapId.load(memory_order_relaxed), h->mBase, h->mSize);
     }
 }


 // ---------------------------------------------------------------------------
 } // namespace android
	/*
	* Copyright (C) 2008 The Android Open Source Project
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	#define LOG_TAG "IMemory"

	#include <atomic>
	#include <stdatomic.h>

	#include <fcntl.h>
	#include <stdint.h>
	#include <stdio.h>
	#include <stdlib.h>
	#include <sys/types.h>
	#include <sys/mman.h>
	#include <unistd.h>

	#include <binder/IMemory.h>
	#include <binder/Parcel.h>
	#include <log/log.h>

	#include <utils/KeyedVector.h>
	#include <utils/threads.h>

	#define VERBOSE 0

	namespace android {
	// ---------------------------------------------------------------------------

	class HeapCache : public IBinder::DeathRecipient
	{
	public:
	HeapCache();
	virtual ~HeapCache();

	virtual void binderDied(const wp<IBinder>& who);

	sp<IMemoryHeap> find_heap(const sp<IBinder>& binder);
	void free_heap(const sp<IBinder>& binder);
	sp<IMemoryHeap> get_heap(const sp<IBinder>& binder);
	void dump_heaps();

	private:
	// For IMemory.cpp
	struct heap_info_t {
	sp<IMemoryHeap> heap;
	int32_t count;
	// Note that this cannot be meaningfully copied.
	};

	void free_heap(const wp<IBinder>& binder);

	Mutex mHeapCacheLock; // Protects entire vector below.
	KeyedVector< wp<IBinder>, heap_info_t > mHeapCache;
	// We do not use the copy-on-write capabilities of KeyedVector.
	// TODO: Reimplemement based on standard C++ container?
	};

	static sp<HeapCache> gHeapCache = sp<HeapCache>::make();

	/******************************************************************************/

	enum {
	HEAP_ID = IBinder::FIRST_CALL_TRANSACTION
	};

	class BpMemoryHeap : public BpInterface<IMemoryHeap>
	{
	public:
	explicit BpMemoryHeap(const sp<IBinder>& impl);
	virtual ~BpMemoryHeap();

	int getHeapID() const override;
	void* getBase() const override;
	size_t getSize() const override;
	uint32_t getFlags() const override;
	off_t getOffset() const override;

	private:
	friend class IMemory;
	friend class HeapCache;

	// for debugging in this module
	static inline sp<IMemoryHeap> find_heap(const sp<IBinder>& binder) {
	return gHeapCache->find_heap(binder);
	}
	static inline void free_heap(const sp<IBinder>& binder) {
	gHeapCache->free_heap(binder);
	}
	static inline sp<IMemoryHeap> get_heap(const sp<IBinder>& binder) {
	return gHeapCache->get_heap(binder);
	}
	static inline void dump_heaps() {
	gHeapCache->dump_heaps();
	}

	void assertMapped() const;
	void assertReallyMapped() const;

	mutable std::atomic<int32_t> mHeapId;
	mutable void* mBase;
	mutable size_t mSize;
	mutable uint32_t mFlags;
	mutable off_t mOffset;
	mutable bool mRealHeap;
	mutable Mutex mLock;
	};

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

	enum {
	GET_MEMORY = IBinder::FIRST_CALL_TRANSACTION
	};

	class BpMemory : public BpInterface<IMemory>
	{
	public:
	explicit BpMemory(const sp<IBinder>& impl);
	virtual ~BpMemory();
	// NOLINTNEXTLINE(google-default-arguments)
	virtual sp<IMemoryHeap> getMemory(ssize_t* offset=nullptr, size_t* size=nullptr) const;

	private:
	mutable sp<IMemoryHeap> mHeap;
	mutable ssize_t mOffset;
	mutable size_t mSize;
	};

	/******************************************************************************/

	void* IMemory::fastPointer(const sp<IBinder>& binder, ssize_t offset) const
	{
	sp<IMemoryHeap> realHeap = BpMemoryHeap::get_heap(binder);
	void* const base = realHeap->base();
	if (base == MAP_FAILED)
	return nullptr;
	return static_cast<char*>(base) + offset;
	}

	void* IMemory::unsecurePointer() const {
	ssize_t offset;
	sp<IMemoryHeap> heap = getMemory(&offset);
	void* const base = heap!=nullptr ? heap->base() : MAP_FAILED;
	if (base == MAP_FAILED)
	return nullptr;
	return static_cast<char*>(base) + offset;
	}

	void* IMemory::pointer() const { return unsecurePointer(); }

	size_t IMemory::size() const {
	size_t size;
	getMemory(nullptr, &size);
	return size;
	}

	ssize_t IMemory::offset() const {
	ssize_t offset;
	getMemory(&offset);
	return offset;
	}

	/******************************************************************************/

	BpMemory::BpMemory(const sp<IBinder>& impl)
	: BpInterface<IMemory>(impl), mOffset(0), mSize(0)
	{
	}

	BpMemory::~BpMemory()
	{
	}

	// NOLINTNEXTLINE(google-default-arguments)
	sp<IMemoryHeap> BpMemory::getMemory(ssize_t* offset, size_t* size) const
	{
	if (mHeap == nullptr) {
	Parcel data, reply;
	data.writeInterfaceToken(IMemory::getInterfaceDescriptor());
	if (remote()->transact(GET_MEMORY, data, &reply) == NO_ERROR) {
	sp<IBinder> heap = reply.readStrongBinder();
	if (heap != nullptr) {
	mHeap = interface_cast<IMemoryHeap>(heap);
	if (mHeap != nullptr) {
	const int64_t offset64 = reply.readInt64();
	const uint64_t size64 = reply.readUint64();
	const ssize_t o = (ssize_t)offset64;
	const size_t s = (size_t)size64;
	size_t heapSize = mHeap->getSize();
	if (s == size64 && o == offset64 // ILP32 bounds check
	&& s <= heapSize
	&& o >= 0
	&& (static_cast<size_t>(o) <= heapSize - s)) {
	mOffset = o;
	mSize = s;
	} else {
	// Hm.
	android_errorWriteWithInfoLog(0x534e4554,
	"26877992", -1, nullptr, 0);
	mOffset = 0;
	mSize = 0;
	}
	}
	}
	}
	}
	if (offset) *offset = mOffset;
	if (size) *size = mSize;
	return (mSize > 0) ? mHeap : nullptr;
	}

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

	IMPLEMENT_META_INTERFACE(Memory, "android.utils.IMemory")

	BnMemory::BnMemory() {
	}

	BnMemory::~BnMemory() {
	}

	// NOLINTNEXTLINE(google-default-arguments)
	status_t BnMemory::onTransact(
	uint32_t code, const Parcel& data, Parcel* reply, uint32_t flags)
	{
	switch(code) {
	case GET_MEMORY: {
	CHECK_INTERFACE(IMemory, data, reply);
	ssize_t offset;
	size_t size;
	reply->writeStrongBinder( IInterface::asBinder(getMemory(&offset, &size)) );
	reply->writeInt64(offset);
	reply->writeUint64(size);
	return NO_ERROR;
	} break;
	default:
	return BBinder::onTransact(code, data, reply, flags);
	}
	}


	/******************************************************************************/

	BpMemoryHeap::BpMemoryHeap(const sp<IBinder>& impl)
	: BpInterface<IMemoryHeap>(impl),
	mHeapId(-1), mBase(MAP_FAILED), mSize(0), mFlags(0), mOffset(0), mRealHeap(false)
	{
	}

	BpMemoryHeap::~BpMemoryHeap() {
	int32_t heapId = mHeapId.load(memory_order_relaxed);
	if (heapId != -1) {
	close(heapId);
	if (mRealHeap) {
	// by construction we're the last one
	if (mBase != MAP_FAILED) {
	sp<IBinder> binder = IInterface::asBinder(this);

	if (VERBOSE) {
	ALOGD("UNMAPPING binder=%p, heap=%p, size=%zu, fd=%d",
	binder.get(), this, mSize, heapId);
	}

	munmap(mBase, mSize);
	}
	} else {
	// remove from list only if it was mapped before
	sp<IBinder> binder = IInterface::asBinder(this);
	free_heap(binder);
	}
	}
	}

	void BpMemoryHeap::assertMapped() const
	{
	int32_t heapId = mHeapId.load(memory_order_acquire);
	if (heapId == -1) {
	sp<IBinder> binder(IInterface::asBinder(const_cast<BpMemoryHeap*>(this)));
	sp<BpMemoryHeap> heap = sp<BpMemoryHeap>::cast(find_heap(binder));
	heap->assertReallyMapped();
	if (heap->mBase != MAP_FAILED) {
	Mutex::Autolock _l(mLock);
	if (mHeapId.load(memory_order_relaxed) == -1) {
	mBase = heap->mBase;
	mSize = heap->mSize;
	mOffset = heap->mOffset;
	int fd = fcntl(heap->mHeapId.load(memory_order_relaxed), F_DUPFD_CLOEXEC, 0);
	ALOGE_IF(fd==-1, "cannot dup fd=%d",
	heap->mHeapId.load(memory_order_relaxed));
	mHeapId.store(fd, memory_order_release);
	}
	} else {
	// something went wrong
	free_heap(binder);
	}
	}
	}

	void BpMemoryHeap::assertReallyMapped() const
	{
	int32_t heapId = mHeapId.load(memory_order_acquire);
	if (heapId == -1) {

	// remote call without mLock held, worse case scenario, we end up
	// calling transact() from multiple threads, but that's not a problem,
	// only mmap below must be in the critical section.

	Parcel data, reply;
	data.writeInterfaceToken(IMemoryHeap::getInterfaceDescriptor());
	status_t err = remote()->transact(HEAP_ID, data, &reply);
	int parcel_fd = reply.readFileDescriptor();
	const uint64_t size64 = reply.readUint64();
	const int64_t offset64 = reply.readInt64();
	const uint32_t flags = reply.readUint32();
	const size_t size = (size_t)size64;
	const off_t offset = (off_t)offset64;
	if (err != NO_ERROR \|\| // failed transaction
	size != size64 \|\| offset != offset64) { // ILP32 size check
	ALOGE("binder=%p transaction failed fd=%d, size=%zu, err=%d (%s)",
	IInterface::asBinder(this).get(),
	parcel_fd, size, err, strerror(-err));
	return;
	}

	Mutex::Autolock _l(mLock);
	if (mHeapId.load(memory_order_relaxed) == -1) {
	int fd = fcntl(parcel_fd, F_DUPFD_CLOEXEC, 0);
	ALOGE_IF(fd == -1, "cannot dup fd=%d, size=%zu, err=%d (%s)",
	parcel_fd, size, err, strerror(errno));

	int access = PROT_READ;
	if (!(flags & READ_ONLY)) {
	access \|= PROT_WRITE;
	}
	mRealHeap = true;
	mBase = mmap(nullptr, size, access, MAP_SHARED, fd, offset);
	if (mBase == MAP_FAILED) {
	ALOGE("cannot map BpMemoryHeap (binder=%p), size=%zu, fd=%d (%s)",
	IInterface::asBinder(this).get(), size, fd, strerror(errno));
	close(fd);
	} else {
	mSize = size;
	mFlags = flags;
	mOffset = offset;
	mHeapId.store(fd, memory_order_release);
	}
	}
	}
	}

	int BpMemoryHeap::getHeapID() const {
	assertMapped();
	// We either stored mHeapId ourselves, or loaded it with acquire semantics.
	return mHeapId.load(memory_order_relaxed);
	}

	void* BpMemoryHeap::getBase() const {
	assertMapped();
	return mBase;
	}

	size_t BpMemoryHeap::getSize() const {
	assertMapped();
	return mSize;
	}

	uint32_t BpMemoryHeap::getFlags() const {
	assertMapped();
	return mFlags;
	}

	off_t BpMemoryHeap::getOffset() const {
	assertMapped();
	return mOffset;
	}

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

	IMPLEMENT_META_INTERFACE(MemoryHeap, "android.utils.IMemoryHeap")

	BnMemoryHeap::BnMemoryHeap() {
	}

	BnMemoryHeap::~BnMemoryHeap() {
	}

	// NOLINTNEXTLINE(google-default-arguments)
	status_t BnMemoryHeap::onTransact(
	uint32_t code, const Parcel& data, Parcel* reply, uint32_t flags)
	{
	switch(code) {
	case HEAP_ID: {
	CHECK_INTERFACE(IMemoryHeap, data, reply);
	reply->writeFileDescriptor(getHeapID());
	reply->writeUint64(getSize());
	reply->writeInt64(getOffset());
	reply->writeUint32(getFlags());
	return NO_ERROR;
	} break;
	default:
	return BBinder::onTransact(code, data, reply, flags);
	}
	}

	/*****************************************************************************/

	HeapCache::HeapCache()
	: DeathRecipient()
	{
	}

	HeapCache::~HeapCache()
	{
	}

	void HeapCache::binderDied(const wp<IBinder>& binder)
	{
	//ALOGD("binderDied binder=%p", binder.unsafe_get());
	free_heap(binder);
	}

	sp<IMemoryHeap> HeapCache::find_heap(const sp<IBinder>& binder)
	{
	Mutex::Autolock _l(mHeapCacheLock);
	ssize_t i = mHeapCache.indexOfKey(binder);
	if (i>=0) {
	heap_info_t& info = mHeapCache.editValueAt(i);
	ALOGD_IF(VERBOSE,
	"found binder=%p, heap=%p, size=%zu, fd=%d, count=%d",
	binder.get(), info.heap.get(),
	static_cast<BpMemoryHeap*>(info.heap.get())->mSize,
	static_cast<BpMemoryHeap*>(info.heap.get())
	->mHeapId.load(memory_order_relaxed),
	info.count);
	++info.count;
	return info.heap;
	} else {
	heap_info_t info;
	info.heap = interface_cast<IMemoryHeap>(binder);
	info.count = 1;
	//ALOGD("adding binder=%p, heap=%p, count=%d",
	// binder.get(), info.heap.get(), info.count);
	mHeapCache.add(binder, info);
	return info.heap;
	}
	}

	void HeapCache::free_heap(const sp<IBinder>& binder) {
	free_heap( wp<IBinder>(binder) );
	}

	void HeapCache::free_heap(const wp<IBinder>& binder)
	{
	sp<IMemoryHeap> rel;
	{
	Mutex::Autolock _l(mHeapCacheLock);
	ssize_t i = mHeapCache.indexOfKey(binder);
	if (i>=0) {
	heap_info_t& info(mHeapCache.editValueAt(i));
	if (--info.count == 0) {
	ALOGD_IF(VERBOSE,
	"removing binder=%p, heap=%p, size=%zu, fd=%d, count=%d",
	binder.unsafe_get(), info.heap.get(),
	static_cast<BpMemoryHeap*>(info.heap.get())->mSize,
	static_cast<BpMemoryHeap*>(info.heap.get())
	->mHeapId.load(memory_order_relaxed),
	info.count);
	rel = mHeapCache.valueAt(i).heap;
	mHeapCache.removeItemsAt(i);
	}
	} else {
	ALOGE("free_heap binder=%p not found!!!", binder.unsafe_get());
	}
	}
	}

	sp<IMemoryHeap> HeapCache::get_heap(const sp<IBinder>& binder)
	{
	sp<IMemoryHeap> realHeap;
	Mutex::Autolock _l(mHeapCacheLock);
	ssize_t i = mHeapCache.indexOfKey(binder);
	if (i>=0) realHeap = mHeapCache.valueAt(i).heap;
	else realHeap = interface_cast<IMemoryHeap>(binder);
	return realHeap;
	}

	void HeapCache::dump_heaps()
	{
	Mutex::Autolock _l(mHeapCacheLock);
	int c = mHeapCache.size();
	for (int i=0 ; i<c ; i++) {
	const heap_info_t& info = mHeapCache.valueAt(i);
	BpMemoryHeap const* h(static_cast<BpMemoryHeap const *>(info.heap.get()));
	ALOGD("hey=%p, heap=%p, count=%d, (fd=%d, base=%p, size=%zu)",
	mHeapCache.keyAt(i).unsafe_get(),
	info.heap.get(), info.count,
	h->mHeapId.load(memory_order_relaxed), h->mBase, h->mSize);
	}
	}


	// ---------------------------------------------------------------------------
	} // namespace android