| /* |
| * Copyright (C) 2014 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. |
| */ |
| |
| #ifndef __LINKER_BLOCK_ALLOCATOR_H |
| #define __LINKER_BLOCK_ALLOCATOR_H |
| |
| #include <stdlib.h> |
| #include <limits.h> |
| #include "private/bionic_macros.h" |
| |
| struct LinkerBlockAllocatorPage; |
| |
| /* |
| * This class is a non-template version of the LinkerTypeAllocator |
| * It keeps code inside .cpp file by keeping the interface |
| * template-free. |
| * |
| * Please use LinkerTypeAllocator<type> where possible (everywhere). |
| */ |
| class LinkerBlockAllocator { |
| public: |
| explicit LinkerBlockAllocator(size_t block_size); |
| |
| void* alloc(); |
| void free(void* block); |
| void protect_all(int prot); |
| |
| private: |
| void create_new_page(); |
| LinkerBlockAllocatorPage* find_page(void* block); |
| |
| size_t block_size_; |
| LinkerBlockAllocatorPage* page_list_; |
| void* free_block_list_; |
| |
| DISALLOW_COPY_AND_ASSIGN(LinkerBlockAllocator); |
| }; |
| |
| /* |
| * A simple allocator for the dynamic linker. An allocator allocates instances |
| * of a single fixed-size type. Allocations are backed by page-sized private |
| * anonymous mmaps. |
| * |
| * The differences between this allocator and LinkerMemoryAllocator are: |
| * 1. This allocator manages space more efficiently. LinkerMemoryAllocator |
| * operates in power-of-two sized blocks up to 1k, when this implementation |
| * splits the page to aligned size of structure; For example for structures |
| * with size 513 this allocator will use 516 (520 for lp64) bytes of data |
| * where generalized implementation is going to use 1024 sized blocks. |
| * |
| * 2. This allocator does not munmap allocated memory, where LinkerMemoryAllocator does. |
| * |
| * 3. This allocator provides mprotect services to the user, where LinkerMemoryAllocator |
| * always treats it's memory as READ|WRITE. |
| */ |
| template<typename T> |
| class LinkerTypeAllocator { |
| public: |
| LinkerTypeAllocator() : block_allocator_(sizeof(T)) {} |
| T* alloc() { return reinterpret_cast<T*>(block_allocator_.alloc()); } |
| void free(T* t) { block_allocator_.free(t); } |
| void protect_all(int prot) { block_allocator_.protect_all(prot); } |
| private: |
| LinkerBlockAllocator block_allocator_; |
| DISALLOW_COPY_AND_ASSIGN(LinkerTypeAllocator); |
| }; |
| |
| #endif // __LINKER_BLOCK_ALLOCATOR_H |