platform_bionic/linker/linker_mapped_file_fragment.cpp
Dmitriy Ivanov 84bab5a955 Move some utility functions to linker_utils
Also adds unit-tests for page_start, page_offset, and safe_add

Change-Id: Ia1325b4682d367328a01599a19848e4ffcd2c0ea
2015-11-20 21:37:51 +00:00

63 lines
1.8 KiB
C++

/*
* Copyright (C) 2015 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.
*/
#include "linker_mapped_file_fragment.h"
#include "linker_debug.h"
#include "linker_utils.h"
#include <inttypes.h>
#include <stdlib.h>
#include <sys/mman.h>
#include <unistd.h>
MappedFileFragment::MappedFileFragment() : map_start_(nullptr), map_size_(0),
data_(nullptr), size_ (0)
{ }
MappedFileFragment::~MappedFileFragment() {
if (map_start_ != nullptr) {
munmap(map_start_, map_size_);
}
}
bool MappedFileFragment::Map(int fd, off64_t base_offset, size_t elf_offset, size_t size) {
off64_t offset;
CHECK(safe_add(&offset, base_offset, elf_offset));
off64_t page_min = page_start(offset);
off64_t end_offset;
CHECK(safe_add(&end_offset, offset, size));
CHECK(safe_add(&end_offset, end_offset, page_offset(offset)));
size_t map_size = static_cast<size_t>(end_offset - page_min);
CHECK(map_size >= size);
uint8_t* map_start = static_cast<uint8_t*>(
mmap64(nullptr, map_size, PROT_READ, MAP_PRIVATE, fd, page_min));
if (map_start == MAP_FAILED) {
return false;
}
map_start_ = map_start;
map_size_ = map_size;
data_ = map_start + page_offset(offset);
size_ = size;
return true;
}