1 /*
2 * Copyright (C) 2015 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 #include "linker_mapped_file_fragment.h"
18 #include "linker_debug.h"
19 #include "linker_utils.h"
20
21 #include <inttypes.h>
22 #include <stdlib.h>
23 #include <sys/mman.h>
24 #include <unistd.h>
25
MappedFileFragment()26 MappedFileFragment::MappedFileFragment() : map_start_(nullptr), map_size_(0),
27 data_(nullptr), size_ (0)
28 { }
29
~MappedFileFragment()30 MappedFileFragment::~MappedFileFragment() {
31 if (map_start_ != nullptr) {
32 munmap(map_start_, map_size_);
33 }
34 }
35
Map(int fd,off64_t base_offset,size_t elf_offset,size_t size)36 bool MappedFileFragment::Map(int fd, off64_t base_offset, size_t elf_offset, size_t size) {
37 off64_t offset;
38 CHECK(safe_add(&offset, base_offset, elf_offset));
39
40 off64_t page_min = page_start(offset);
41 off64_t end_offset;
42
43 CHECK(safe_add(&end_offset, offset, size));
44 CHECK(safe_add(&end_offset, end_offset, page_offset(offset)));
45
46 size_t map_size = static_cast<size_t>(end_offset - page_min);
47 CHECK(map_size >= size);
48
49 uint8_t* map_start = static_cast<uint8_t*>(
50 mmap64(nullptr, map_size, PROT_READ, MAP_PRIVATE, fd, page_min));
51
52 if (map_start == MAP_FAILED) {
53 return false;
54 }
55
56 map_start_ = map_start;
57 map_size_ = map_size;
58
59 data_ = map_start + page_offset(offset);
60 size_ = size;
61
62 return true;
63 }
64