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/* Copyright (C) 2007-2010 The Android Open Source Project
**
** This software is licensed under the terms of the GNU General Public
** License version 2, as published by the Free Software Foundation, and
** may be copied, distributed, and modified under those terms.
**
** This program is distributed in the hope that it will be useful,
** but WITHOUT ANY WARRANTY; without even the implied warranty of
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
** GNU General Public License for more details.
*/
/*
* Contains implementation of a class ElfMappedSection, that encapsulates
* a section of an ELF file, mapped to memory.
*/
#include "elf_defs.h"
#include "elf_mapped_section.h"
ElfMappedSection::ElfMappedSection()
: mapped_at_(NULL),
data_(NULL),
size_(0) {
}
ElfMappedSection::~ElfMappedSection() {
if (mapped_at_ != NULL) {
#ifdef WIN32
UnmapViewOfFile(mapped_at_);
#else // WIN32
munmap(mapped_at_, diff_ptr(mapped_at_, data_) + size_);
#endif // WIN32
}
}
bool ElfMappedSection::map(ELF_FILE_HANDLE handle,
Elf_Xword offset,
Elf_Word size) {
/* Get the mask for mapping offset alignment. */
#ifdef WIN32
SYSTEM_INFO sys_info;
GetSystemInfo(&sys_info);
const Elf_Xword align_mask = sys_info.dwAllocationGranularity - 1;
#else // WIN32
const Elf_Xword align_mask = getpagesize() - 1;
#endif // WIN32
/* Adjust mapping offset and mapping size accordingly to
* the mapping alignment requirements. */
const Elf_Xword map_offset = offset & ~align_mask;
const Elf_Word map_size = static_cast<Elf_Word>(offset - map_offset + size);
/* Make sure mapping size doesn't exceed 4G: may happen on 64-bit ELFs, if
* section size is close to 4G, while section offset is badly misaligned. */
assert(map_size >= size);
if (map_size < size) {
_set_errno(EFBIG);
return false;
}
/* Map the section. */
#ifdef WIN32
LARGE_INTEGER converter;
converter.QuadPart = map_offset + map_size;
HANDLE map_handle = CreateFileMapping(handle, NULL, PAGE_READONLY,
converter.HighPart, converter.LowPart,
NULL);
assert(map_handle != NULL);
if (map_handle != NULL) {
converter.QuadPart = map_offset;
mapped_at_ = MapViewOfFile(map_handle, FILE_MAP_READ, converter.HighPart,
converter.LowPart, map_size);
assert(mapped_at_ != NULL);
/* Memory mapping (if successful) will hold extra references to the
* mapping, so we can close it right after we mapped file view. */
CloseHandle(map_handle);
}
if (mapped_at_ == NULL) {
_set_errno(GetLastError());
return false;
}
#else // WIN32
mapped_at_ = mmap(0, map_size, PROT_READ, MAP_SHARED, handle, map_offset);
assert(mapped_at_ != MAP_FAILED);
if (mapped_at_ == MAP_FAILED) {
return false;
}
#endif // WIN32
data_ = INC_CPTR(mapped_at_, offset - map_offset);
size_ = size;
return true;
}
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