blob: 4b9b9952631fd2f17558def572420b4c306e8d46 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
|
/*
* 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
|
