| /* |
| * Copyright (C) 2014 The Android Open Source Project |
| * All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * * Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * * Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in |
| * the documentation and/or other materials provided with the |
| * distribution. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS |
| * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE |
| * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, |
| * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, |
| * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS |
| * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED |
| * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, |
| * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT |
| * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| * SUCH DAMAGE. |
| */ |
| |
| #pragma once |
| |
| #include <stdlib.h> |
| #include <limits.h> |
| |
| #include <android-base/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); |
| }; |