145 lines
3.8 KiB
C++
145 lines
3.8 KiB
C++
// Copyright 2013 The Chromium Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#include "base/files/memory_mapped_file.h"
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#include <utility>
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#include "base/files/file_path.h"
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#include "base/logging.h"
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#include "base/numerics/safe_math.h"
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#include "base/system/sys_info.h"
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#include "build/build_config.h"
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namespace base {
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const MemoryMappedFile::Region MemoryMappedFile::Region::kWholeFile = {0, 0};
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bool MemoryMappedFile::Region::operator==(
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const MemoryMappedFile::Region& other) const {
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return other.offset == offset && other.size == size;
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}
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bool MemoryMappedFile::Region::operator!=(
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const MemoryMappedFile::Region& other) const {
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return other.offset != offset || other.size != size;
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}
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MemoryMappedFile::~MemoryMappedFile() {
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CloseHandles();
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}
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#if !defined(OS_NACL)
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bool MemoryMappedFile::Initialize(const FilePath& file_name, Access access) {
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if (IsValid())
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return false;
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uint32_t flags = 0;
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switch (access) {
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case READ_ONLY:
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flags = File::FLAG_OPEN | File::FLAG_READ;
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break;
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case READ_WRITE:
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flags = File::FLAG_OPEN | File::FLAG_READ | File::FLAG_WRITE;
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break;
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case READ_WRITE_EXTEND:
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// Can't open with "extend" because no maximum size is known.
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NOTREACHED();
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break;
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#if defined(OS_WIN)
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case READ_CODE_IMAGE:
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flags |= File::FLAG_OPEN | File::FLAG_READ | File::FLAG_EXCLUSIVE_WRITE |
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File::FLAG_EXECUTE;
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break;
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#endif
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}
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file_.Initialize(file_name, flags);
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if (!file_.IsValid()) {
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DLOG(ERROR) << "Couldn't open " << file_name.AsUTF8Unsafe();
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return false;
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}
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if (!MapFileRegionToMemory(Region::kWholeFile, access)) {
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CloseHandles();
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return false;
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}
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return true;
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}
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bool MemoryMappedFile::Initialize(File file, Access access) {
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DCHECK_NE(READ_WRITE_EXTEND, access);
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return Initialize(std::move(file), Region::kWholeFile, access);
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}
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bool MemoryMappedFile::Initialize(File file,
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const Region& region,
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Access access) {
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switch (access) {
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case READ_WRITE_EXTEND:
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DCHECK(Region::kWholeFile != region);
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{
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CheckedNumeric<int64_t> region_end(region.offset);
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region_end += region.size;
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if (!region_end.IsValid()) {
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DLOG(ERROR) << "Region bounds exceed maximum for base::File.";
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return false;
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}
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}
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FALLTHROUGH;
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case READ_ONLY:
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case READ_WRITE:
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// Ensure that the region values are valid.
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if (region.offset < 0) {
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DLOG(ERROR) << "Region bounds are not valid.";
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return false;
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}
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break;
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#if defined(OS_WIN)
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case READ_CODE_IMAGE:
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// Can't open with "READ_CODE_IMAGE", not supported outside Windows
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// or with a |region|.
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NOTREACHED();
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break;
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#endif
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}
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if (IsValid())
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return false;
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if (region != Region::kWholeFile)
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DCHECK_GE(region.offset, 0);
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file_ = std::move(file);
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if (!MapFileRegionToMemory(region, access)) {
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CloseHandles();
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return false;
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}
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return true;
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}
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bool MemoryMappedFile::IsValid() const {
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return data_ != nullptr;
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}
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// static
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void MemoryMappedFile::CalculateVMAlignedBoundaries(int64_t start,
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size_t size,
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int64_t* aligned_start,
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size_t* aligned_size,
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int32_t* offset) {
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// Sadly, on Windows, the mmap alignment is not just equal to the page size.
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auto mask = SysInfo::VMAllocationGranularity() - 1;
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DCHECK(IsValueInRangeForNumericType<int32_t>(mask));
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*offset = start & mask;
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*aligned_start = start & ~mask;
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*aligned_size = (size + *offset + mask) & ~mask;
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}
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#endif // !defined(OS_NACL)
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} // namespace base
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