19656ce537
Add basic general purpose memory allocator to linker in order to enable usage of other libraries like libziparchive. Change-Id: I4a680ebb36ed5ba67c61249f81dba9f567808434
82 lines
2.7 KiB
C++
82 lines
2.7 KiB
C++
/*
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* Copyright (C) 2014 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifndef __LINKER_BLOCK_ALLOCATOR_H
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#define __LINKER_BLOCK_ALLOCATOR_H
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#include <stdlib.h>
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#include <limits.h>
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#include "private/bionic_macros.h"
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struct LinkerBlockAllocatorPage;
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/*
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* This class is a non-template version of the LinkerTypeAllocator
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* It keeps code inside .cpp file by keeping the interface
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* template-free.
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*
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* Please use LinkerTypeAllocator<type> where possible (everywhere).
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*/
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class LinkerBlockAllocator {
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public:
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explicit LinkerBlockAllocator(size_t block_size);
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void* alloc();
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void free(void* block);
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void protect_all(int prot);
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private:
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void create_new_page();
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LinkerBlockAllocatorPage* find_page(void* block);
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size_t block_size_;
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LinkerBlockAllocatorPage* page_list_;
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void* free_block_list_;
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DISALLOW_COPY_AND_ASSIGN(LinkerBlockAllocator);
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};
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/*
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* A simple allocator for the dynamic linker. An allocator allocates instances
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* of a single fixed-size type. Allocations are backed by page-sized private
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* anonymous mmaps.
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*
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* The differences between this allocator and LinkerMemoryAllocator are:
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* 1. This allocator manages space more efficiently. LinkerMemoryAllocator
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* operates in power-of-two sized blocks up to 1k, when this implementation
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* splits the page to aligned size of structure; For example for structures
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* with size 513 this allocator will use 516 (520 for lp64) bytes of data
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* where generalized implementation is going to use 1024 sized blocks.
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*
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* 2. This allocator does not munmap allocated memory, where LinkerMemoryAllocator does.
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*
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* 3. This allocator provides mprotect services to the user, where LinkerMemoryAllocator
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* always treats it's memory as READ|WRITE.
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*/
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template<typename T>
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class LinkerTypeAllocator {
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public:
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LinkerTypeAllocator() : block_allocator_(sizeof(T)) {}
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T* alloc() { return reinterpret_cast<T*>(block_allocator_.alloc()); }
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void free(T* t) { block_allocator_.free(t); }
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void protect_all(int prot) { block_allocator_.protect_all(prot); }
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private:
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LinkerBlockAllocator block_allocator_;
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DISALLOW_COPY_AND_ASSIGN(LinkerTypeAllocator);
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};
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#endif // __LINKER_BLOCK_ALLOCATOR_H
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