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 */
17 #ifndef __LINKER_ALLOCATOR_H
18 #define __LINKER_ALLOCATOR_H
20 #include <stdlib.h>
21 #include <limits.h>
22 #include "private/bionic_macros.h"
24 struct LinkerAllocatorPage;
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 */
33 class LinkerBlockAllocator {
34 public:
35 LinkerBlockAllocator();
37 void init(size_t block_size);
38 void* alloc();
39 void free(void* block);
40 void protect_all(int prot);
42 private:
43 void create_new_page();
44 LinkerAllocatorPage* find_page(void* block);
46 size_t block_size_;
47 LinkerAllocatorPage* page_list_;
48 void* free_block_list_;
50 DISALLOW_COPY_AND_ASSIGN(LinkerBlockAllocator);
51 };
53 /*
54 * A simple allocator for the dynamic linker. An allocator allocates instances
55 * of a single fixed-size type. Allocations are backed by page-sized private
56 * anonymous mmaps.
57 */
58 template<typename T>
59 class LinkerAllocator {
60 public:
61 LinkerAllocator() : block_allocator_() {}
62 void init() { block_allocator_.init(sizeof(T)); }
63 T* alloc() { return reinterpret_cast<T*>(block_allocator_.alloc()); }
64 void free(T* t) { block_allocator_.free(t); }
65 void protect_all(int prot) { block_allocator_.protect_all(prot); }
66 private:
67 LinkerBlockAllocator block_allocator_;
68 DISALLOW_COPY_AND_ASSIGN(LinkerAllocator);
69 };
70 #endif // __LINKER_ALLOCATOR_H