123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111 |
- // Copyright 2013 The Chromium Authors. All rights reserved.
- // 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 <fcntl.h>
- #include <stddef.h>
- #include <stdint.h>
- #include <sys/mman.h>
- #include <sys/stat.h>
- #include <unistd.h>
- #include "base/files/file_util.h"
- #include "base/logging.h"
- #include "base/numerics/safe_conversions.h"
- #include "base/threading/scoped_blocking_call.h"
- #include "build/build_config.h"
- namespace base {
- MemoryMappedFile::MemoryMappedFile() : data_(nullptr), length_(0) {}
- #if !BUILDFLAG(IS_NACL)
- bool MemoryMappedFile::MapFileRegionToMemory(
- const MemoryMappedFile::Region& region,
- Access access) {
- ScopedBlockingCall scoped_blocking_call(FROM_HERE, BlockingType::MAY_BLOCK);
- off_t map_start = 0;
- size_t map_size = 0;
- int32_t data_offset = 0;
- if (region == MemoryMappedFile::Region::kWholeFile) {
- int64_t file_len = file_.GetLength();
- if (file_len < 0) {
- DPLOG(ERROR) << "fstat " << file_.GetPlatformFile();
- return false;
- }
- if (!IsValueInRangeForNumericType<size_t>(file_len))
- return false;
- map_size = static_cast<size_t>(file_len);
- length_ = map_size;
- } else {
- // The region can be arbitrarily aligned. mmap, instead, requires both the
- // start and size to be page-aligned. Hence, we map here the page-aligned
- // 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 aligned_size = 0;
- CalculateVMAlignedBoundaries(region.offset,
- region.size,
- &aligned_start,
- &aligned_size,
- &data_offset);
- // Ensure that the casts in the mmap call below are sane.
- if (aligned_start < 0 ||
- !IsValueInRangeForNumericType<off_t>(aligned_start)) {
- DLOG(ERROR) << "Region bounds are not valid for mmap";
- return false;
- }
- map_start = static_cast<off_t>(aligned_start);
- map_size = aligned_size;
- length_ = region.size;
- }
- int flags = 0;
- switch (access) {
- case READ_ONLY:
- flags |= PROT_READ;
- break;
- case READ_WRITE:
- flags |= PROT_READ | PROT_WRITE;
- break;
- case READ_WRITE_EXTEND:
- flags |= PROT_READ | PROT_WRITE;
- if (!AllocateFileRegion(&file_, region.offset, region.size))
- return false;
- break;
- }
- data_ = static_cast<uint8_t*>(mmap(nullptr, map_size, flags, MAP_SHARED,
- file_.GetPlatformFile(), map_start));
- if (data_ == MAP_FAILED) {
- DPLOG(ERROR) << "mmap " << file_.GetPlatformFile();
- return false;
- }
- data_ += data_offset;
- return true;
- }
- #endif
- void MemoryMappedFile::CloseHandles() {
- ScopedBlockingCall scoped_blocking_call(FROM_HERE, BlockingType::MAY_BLOCK);
- if (data_ != nullptr)
- munmap(data_, length_);
- file_.Close();
- data_ = nullptr;
- length_ = 0;
- }
- } // namespace base
|