blob: 7169fba5a68531208a580a9b6651bf7b8d9aa02b [file] [log] [blame]
// Copyright 2013 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "base/files/memory_mapped_file.h"
#include <stddef.h>
#include <stdint.h>
#include <limits>
#include <string>
#include "base/files/file_path.h"
#include "base/logging.h"
#include "base/numerics/checked_math.h"
#include "base/threading/scoped_blocking_call.h"
#include "base/win/pe_image.h"
#include <windows.h>
#include <winnt.h> // NOLINT(build/include_order)
namespace base {
MemoryMappedFile::MemoryMappedFile() = default;
bool MemoryMappedFile::MapImageToMemory(Access access) {
ScopedBlockingCall scoped_blocking_call(FROM_HERE, BlockingType::MAY_BLOCK);
// The arguments to the calls of ::CreateFile(), ::CreateFileMapping(), and
// ::MapViewOfFile() need to be self consistent as far as access rights and
// type of mapping or one or more of them will fail in non-obvious ways.
if (!file_.IsValid())
return false;
file_mapping_.Set(::CreateFileMapping(file_.GetPlatformFile(), nullptr,
PAGE_READONLY | SEC_IMAGE_NO_EXECUTE, 0,
0, NULL));
if (!file_mapping_.is_valid())
return false;
data_ = static_cast<uint8_t*>(
::MapViewOfFile(file_mapping_.get(), FILE_MAP_READ, 0, 0, 0));
if (!data_)
return false;
// We need to know how large the mapped file is in some cases
base::win::PEImage pe_image(data_);
length_ = pe_image.GetNTHeaders()->OptionalHeader.SizeOfImage;
return true;
}
bool MemoryMappedFile::MapFileRegionToMemory(
const MemoryMappedFile::Region& region,
Access access) {
ScopedBlockingCall scoped_blocking_call(FROM_HERE, BlockingType::MAY_BLOCK);
DCHECK(access != READ_CODE_IMAGE || region == Region::kWholeFile);
if (!file_.IsValid())
return false;
DWORD flags = 0;
ULARGE_INTEGER size = {};
switch (access) {
case READ_ONLY:
flags |= PAGE_READONLY;
break;
case READ_WRITE:
flags |= PAGE_READWRITE;
break;
case READ_WRITE_EXTEND:
flags |= PAGE_READWRITE;
size.QuadPart = region.size;
break;
case READ_CODE_IMAGE:
return MapImageToMemory(access);
}
file_mapping_.Set(::CreateFileMapping(file_.GetPlatformFile(), NULL, flags,
size.HighPart, size.LowPart, NULL));
if (!file_mapping_.is_valid())
return false;
ULARGE_INTEGER map_start = {};
SIZE_T map_size = 0;
int32_t data_offset = 0;
if (region == MemoryMappedFile::Region::kWholeFile) {
DCHECK_NE(READ_WRITE_EXTEND, access);
int64_t file_len = file_.GetLength();
if (file_len <= 0 || !IsValueInRangeForNumericType<size_t>(file_len))
return false;
length_ = static_cast<size_t>(file_len);
} else {
// The region can be arbitrarily aligned. MapViewOfFile, instead, requires
// that the start address is aligned to the VM granularity (which is
// typically larger than a page size, for instance 32k).
// Also, conversely to POSIX's mmap, the |map_size| doesn't have to be
// aligned and must be less than or equal the mapped file size.
// We map here the outer region [|aligned_start|, |aligned_start+size|]
// which contains |region| and then add up the |data_offset| displacement.
int64_t aligned_start = 0;
size_t ignored = 0U;
CalculateVMAlignedBoundaries(region.offset, region.size, &aligned_start,
&ignored, &data_offset);
base::CheckedNumeric<SIZE_T> full_map_size = region.size;
full_map_size += data_offset;
// Ensure that the casts below in the MapViewOfFile call are sane.
if (aligned_start < 0 || !full_map_size.IsValid()) {
DLOG(ERROR) << "Region bounds are not valid for MapViewOfFile";
return false;
}
map_start.QuadPart = static_cast<uint64_t>(aligned_start);
map_size = full_map_size.ValueOrDie();
length_ = region.size;
}
data_ = static_cast<uint8_t*>(
::MapViewOfFile(file_mapping_.get(),
(flags & PAGE_READONLY) ? FILE_MAP_READ : FILE_MAP_WRITE,
map_start.HighPart, map_start.LowPart, map_size));
if (data_ == nullptr)
return false;
data_ += data_offset;
return true;
}
void MemoryMappedFile::CloseHandles() {
if (data_)
::UnmapViewOfFile(data_);
if (file_mapping_.is_valid())
file_mapping_.Close();
if (file_.IsValid())
file_.Close();
data_ = nullptr;
length_ = 0;
}
} // namespace base