linker_allocator.h revision d59e50063ad708509f3ad83350be33f5612c4f54 
1/*
2 * Copyright (C) 2014 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#ifndef __LINKER_ALLOCATOR_H
18#define __LINKER_ALLOCATOR_H
19
20#include <stdlib.h>
21#include <limits.h>
22#include "private/bionic_macros.h"
23
24struct LinkerAllocatorPage;
25
26/*
27 * This class is a non-template version of the LinkerAllocator
28 * It keeps code inside .cpp file by keeping the interface
29 * template-free.
30 *
31 * Please use LinkerAllocator<type> where possible (everywhere).
32 */
33class LinkerBlockAllocator {
34 public:
35  LinkerBlockAllocator();
36
37  void init(size_t block_size);
38  void* alloc();
39  void free(void* block);
40  void protect_all(int prot);
41
42 private:
43  void create_new_page();
44  LinkerAllocatorPage* find_page(void* block);
45
46  size_t block_size_;
47  LinkerAllocatorPage* page_list_;
48  void* free_block_list_;
49
50  DISALLOW_COPY_AND_ASSIGN(LinkerBlockAllocator);
51};
52
53/*
54 * We can't use malloc(3) in the dynamic linker.
55 *
56 * A simple allocator for the dynamic linker. An allocator allocates instances
57 * of a single fixed-size type. Allocations are backed by page-sized private
58 * anonymous mmaps.
59 */
60template<typename T>
61class LinkerAllocator {
62 public:
63  LinkerAllocator() : block_allocator_() {}
64  void init() { block_allocator_.init(sizeof(T)); }
65  T* alloc() { return reinterpret_cast<T*>(block_allocator_.alloc()); }
66  void free(T* t) { block_allocator_.free(t); }
67  void protect_all(int prot) { block_allocator_.protect_all(prot); }
68 private:
69  LinkerBlockAllocator block_allocator_;
70  DISALLOW_COPY_AND_ASSIGN(LinkerAllocator);
71};
72#endif // __LINKER_ALLOCATOR_H
73