| /* |
| * 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. |
| */ |
| |
| #pragma once |
| |
| #include <stdlib.h> |
| #include <stdint.h> |
| |
| #include <binder/IMemory.h> |
| |
| |
| namespace android { |
| |
| // --------------------------------------------------------------------------- |
| |
| class MemoryHeapBase : public BnMemoryHeap |
| { |
| public: |
| static constexpr auto MEMFD_ALLOW_SEALING_FLAG = 0x00000800; |
| enum { |
| READ_ONLY = IMemoryHeap::READ_ONLY, |
| // memory won't be mapped locally, but will be mapped in the remote |
| // process. |
| DONT_MAP_LOCALLY = 0x00000100, |
| NO_CACHING = 0x00000200, |
| // Bypass ashmem-libcutils to create a memfd shared region. |
| // Ashmem-libcutils will eventually migrate to memfd. |
| // Memfd has security benefits and supports file sealing. |
| // Calling process will need to modify selinux permissions to |
| // open access to tmpfs files. See audioserver for examples. |
| // This is only valid for size constructor. |
| // For host compilation targets, memfd is stubbed in favor of /tmp |
| // files so sealing is not enforced. |
| FORCE_MEMFD = 0x00000400, |
| // Default opt-out of sealing behavior in memfd to avoid potential DOS. |
| // Clients of shared files can seal at anytime via syscall, leading to |
| // TOC/TOU issues if additional seals prevent access from the creating |
| // process. Alternatively, seccomp fcntl(). |
| MEMFD_ALLOW_SEALING = FORCE_MEMFD | MEMFD_ALLOW_SEALING_FLAG |
| }; |
| |
| /* |
| * maps the memory referenced by fd. but DOESN'T take ownership |
| * of the filedescriptor (it makes a copy with dup() |
| */ |
| MemoryHeapBase(int fd, size_t size, uint32_t flags = 0, off_t offset = 0); |
| |
| /* |
| * maps memory from the given device |
| */ |
| explicit MemoryHeapBase(const char* device, size_t size = 0, uint32_t flags = 0); |
| |
| /* |
| * maps memory from ashmem, with the given name for debugging |
| * if the READ_ONLY flag is set, the memory will be writeable by the calling process, |
| * but not by others. this is NOT the case with the other ctors. |
| */ |
| explicit MemoryHeapBase(size_t size, uint32_t flags = 0, char const* name = nullptr); |
| |
| virtual ~MemoryHeapBase(); |
| |
| /* implement IMemoryHeap interface */ |
| int getHeapID() const override; |
| |
| /* virtual address of the heap. returns MAP_FAILED in case of error */ |
| void* getBase() const override; |
| |
| size_t getSize() const override; |
| uint32_t getFlags() const override; |
| off_t getOffset() const override; |
| |
| const char* getDevice() const; |
| |
| /* this closes this heap -- use carefully */ |
| void dispose(); |
| |
| protected: |
| MemoryHeapBase(); |
| // init() takes ownership of fd |
| status_t init(int fd, void *base, size_t size, |
| int flags = 0, const char* device = nullptr); |
| |
| private: |
| status_t mapfd(int fd, bool writeableByCaller, size_t size, off_t offset = 0); |
| |
| int mFD; |
| size_t mSize; |
| void* mBase; |
| uint32_t mFlags; |
| const char* mDevice; |
| bool mNeedUnmap; |
| off_t mOffset; |
| }; |
| |
| // --------------------------------------------------------------------------- |
| } // namespace android |