| // 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 <sys/mman.h> |
| #include <sys/stat.h> |
| #include <unistd.h> |
| |
| #include "base/logging.h" |
| #include "base/threading/thread_restrictions.h" |
| |
| namespace base { |
| |
| MemoryMappedFile::MemoryMappedFile() : data_(NULL), length_(0) { |
| } |
| |
| #if !defined(OS_NACL) |
| bool MemoryMappedFile::MapFileRegionToMemory( |
| const MemoryMappedFile::Region& region) { |
| ThreadRestrictions::AssertIOAllowed(); |
| |
| off_t map_start = 0; |
| size_t map_size = 0; |
| int32 data_offset = 0; |
| |
| if (region == MemoryMappedFile::Region::kWholeFile) { |
| int64 file_len = file_.GetLength(); |
| if (file_len == -1) { |
| DPLOG(ERROR) << "fstat " << file_.GetPlatformFile(); |
| 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 aligned_start = 0; |
| int64 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 || aligned_size < 0 || |
| aligned_start > std::numeric_limits<off_t>::max() || |
| static_cast<uint64>(aligned_size) > |
| std::numeric_limits<size_t>::max() || |
| static_cast<uint64>(region.size) > std::numeric_limits<size_t>::max()) { |
| DLOG(ERROR) << "Region bounds are not valid for mmap"; |
| return false; |
| } |
| |
| map_start = static_cast<off_t>(aligned_start); |
| map_size = static_cast<size_t>(aligned_size); |
| length_ = static_cast<size_t>(region.size); |
| } |
| |
| data_ = static_cast<uint8*>(mmap(NULL, |
| map_size, |
| PROT_READ, |
| 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() { |
| ThreadRestrictions::AssertIOAllowed(); |
| |
| if (data_ != NULL) |
| munmap(data_, length_); |
| file_.Close(); |
| |
| data_ = NULL; |
| length_ = 0; |
| } |
| |
| } // namespace base |