mirror of
https://github.com/aaru-dps/Aaru.git
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348 lines
11 KiB
C#
348 lines
11 KiB
C#
// /***************************************************************************
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// Aaru Data Preservation Suite
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// ----------------------------------------------------------------------------
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//
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// Filename : File.cs
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// Author(s) : Natalia Portillo <claunia@claunia.com>
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//
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// Component : Microsoft FAT filesystem plugin.
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//
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// --[ Description ] ----------------------------------------------------------
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//
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// Methods to handle files.
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//
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// --[ License ] --------------------------------------------------------------
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//
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// This library is free software; you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as
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// published by the Free Software Foundation; either version 2.1 of the
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// License, or (at your option) any later version.
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//
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// This library is distributed in the hope that it will be useful, but
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// WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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// Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public
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// License along with this library; if not, see <http://www.gnu.org/licenses/>.
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//
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// ----------------------------------------------------------------------------
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// Copyright © 2011-2022 Natalia Portillo
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// ****************************************************************************/
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namespace Aaru.Filesystems;
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using System;
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using System.Collections.Generic;
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using System.IO;
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using System.Linq;
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using Aaru.CommonTypes.Enums;
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using Aaru.CommonTypes.Structs;
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using Aaru.Helpers;
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using FileAttributes = Aaru.CommonTypes.Structs.FileAttributes;
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public sealed partial class FAT
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{
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/// <inheritdoc />
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public ErrorNumber MapBlock(string path, long fileBlock, out long deviceBlock)
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{
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deviceBlock = 0;
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if(!_mounted)
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return ErrorNumber.AccessDenied;
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ErrorNumber err = Stat(path, out FileEntryInfo stat);
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if(err != ErrorNumber.NoError)
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return err;
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if(stat.Attributes.HasFlag(FileAttributes.Directory) &&
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!_debug)
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return ErrorNumber.IsDirectory;
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uint[] clusters = GetClusters((uint)stat.Inode);
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if(fileBlock >= clusters.Length)
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return ErrorNumber.InvalidArgument;
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deviceBlock = (long)(_firstClusterSector + clusters[fileBlock] * _sectorsPerCluster);
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return ErrorNumber.NoError;
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}
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/// <inheritdoc />
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public ErrorNumber GetAttributes(string path, out FileAttributes attributes)
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{
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attributes = new FileAttributes();
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if(!_mounted)
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return ErrorNumber.AccessDenied;
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ErrorNumber err = Stat(path, out FileEntryInfo stat);
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if(err != ErrorNumber.NoError)
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return err;
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attributes = stat.Attributes;
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return ErrorNumber.NoError;
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}
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/// <inheritdoc />
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public ErrorNumber Read(string path, long offset, long size, ref byte[] buf)
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{
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if(!_mounted)
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return ErrorNumber.AccessDenied;
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ErrorNumber err = Stat(path, out FileEntryInfo stat);
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if(err != ErrorNumber.NoError)
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return err;
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if(stat.Attributes.HasFlag(FileAttributes.Directory) &&
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!_debug)
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return ErrorNumber.IsDirectory;
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if(size == 0)
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{
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buf = Array.Empty<byte>();
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return ErrorNumber.NoError;
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}
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if(offset >= stat.Length)
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return ErrorNumber.InvalidArgument;
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if(size + offset >= stat.Length)
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size = stat.Length - offset;
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uint[] clusters = GetClusters((uint)stat.Inode);
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if(clusters is null)
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return ErrorNumber.InvalidArgument;
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long firstCluster = offset / _bytesPerCluster;
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long offsetInCluster = offset % _bytesPerCluster;
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long sizeInClusters = (size + offsetInCluster) / _bytesPerCluster;
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if((size + offsetInCluster) % _bytesPerCluster > 0)
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sizeInClusters++;
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var ms = new MemoryStream();
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for(var i = 0; i < sizeInClusters; i++)
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{
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if(i + firstCluster >= clusters.Length)
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return ErrorNumber.InvalidArgument;
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ErrorNumber errno = _image.ReadSectors(_firstClusterSector + clusters[i + firstCluster] * _sectorsPerCluster,
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_sectorsPerCluster, out byte[] buffer);
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if(errno != ErrorNumber.NoError)
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return errno;
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ms.Write(buffer, 0, buffer.Length);
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}
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ms.Position = offsetInCluster;
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buf = new byte[size];
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ms.Read(buf, 0, (int)size);
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return ErrorNumber.NoError;
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}
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/// <inheritdoc />
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public ErrorNumber Stat(string path, out FileEntryInfo stat)
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{
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stat = null;
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if(!_mounted)
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return ErrorNumber.AccessDenied;
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ErrorNumber err = GetFileEntry(path, out CompleteDirectoryEntry completeEntry);
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if(err != ErrorNumber.NoError)
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return err;
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DirectoryEntry entry = completeEntry.Dirent;
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stat = new FileEntryInfo
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{
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Attributes = new FileAttributes(),
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Blocks = entry.size / _bytesPerCluster,
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BlockSize = _bytesPerCluster,
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Length = entry.size,
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Inode = (ulong)(_fat32 ? (entry.ea_handle << 16) + entry.start_cluster : entry.start_cluster),
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Links = 1
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};
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if(entry.cdate > 0 ||
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entry.ctime > 0)
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stat.CreationTime = DateHandlers.DosToDateTime(entry.cdate, entry.ctime);
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if(_namespace != Namespace.Human)
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{
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if(entry.mdate > 0 ||
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entry.mtime > 0)
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stat.LastWriteTime = DateHandlers.DosToDateTime(entry.mdate, entry.mtime);
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if(entry.ctime_ms > 0)
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stat.CreationTime = stat.CreationTime?.AddMilliseconds(entry.ctime_ms * 10);
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}
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if(entry.size % _bytesPerCluster > 0)
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stat.Blocks++;
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if(entry.attributes.HasFlag(FatAttributes.Subdirectory))
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{
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stat.Attributes |= FileAttributes.Directory;
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if(_fat32 && entry.ea_handle << 16 > 0 ||
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entry.start_cluster > 0)
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stat.Blocks = _fat32 ? GetClusters((uint)((entry.ea_handle << 16) + entry.start_cluster))?.Length ?? 0
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: GetClusters(entry.start_cluster)?.Length ?? 0;
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stat.Length = stat.Blocks * stat.BlockSize;
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}
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if(entry.attributes.HasFlag(FatAttributes.ReadOnly))
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stat.Attributes |= FileAttributes.ReadOnly;
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if(entry.attributes.HasFlag(FatAttributes.Hidden))
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stat.Attributes |= FileAttributes.Hidden;
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if(entry.attributes.HasFlag(FatAttributes.System))
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stat.Attributes |= FileAttributes.System;
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if(entry.attributes.HasFlag(FatAttributes.Archive))
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stat.Attributes |= FileAttributes.Archive;
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if(entry.attributes.HasFlag(FatAttributes.Device))
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stat.Attributes |= FileAttributes.Device;
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return ErrorNumber.NoError;
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}
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uint[] GetClusters(uint startCluster)
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{
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if(startCluster == 0)
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return Array.Empty<uint>();
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if(startCluster >= XmlFsType.Clusters)
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return null;
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List<uint> clusters = new();
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uint nextCluster = startCluster;
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ulong nextSector = nextCluster / _fatEntriesPerSector + _fatFirstSector + (_useFirstFat ? 0 : _sectorsPerFat);
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var nextEntry = (int)(nextCluster % _fatEntriesPerSector);
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ulong currentSector = nextSector;
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ErrorNumber errno = _image.ReadSector(currentSector, out byte[] fatData);
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if(errno != ErrorNumber.NoError)
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return null;
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if(_fat32)
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while((nextCluster & FAT32_MASK) > 0 &&
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(nextCluster & FAT32_MASK) <= FAT32_RESERVED)
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{
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clusters.Add(nextCluster);
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if(currentSector != nextSector)
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{
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errno = _image.ReadSector(nextSector, out fatData);
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if(errno != ErrorNumber.NoError)
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return null;
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currentSector = nextSector;
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}
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nextCluster = BitConverter.ToUInt32(fatData, nextEntry * 4);
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nextSector = nextCluster / _fatEntriesPerSector + _fatFirstSector + (_useFirstFat ? 0 : _sectorsPerFat);
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nextEntry = (int)(nextCluster % _fatEntriesPerSector);
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}
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else if(_fat16)
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while(nextCluster > 0 &&
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nextCluster <= FAT16_RESERVED)
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{
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if(nextCluster > _fatEntries.Length)
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return null;
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clusters.Add(nextCluster);
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nextCluster = _fatEntries[nextCluster];
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}
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else
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while(nextCluster > 0 &&
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nextCluster <= FAT12_RESERVED)
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{
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if(nextCluster > _fatEntries.Length)
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return null;
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clusters.Add(nextCluster);
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nextCluster = _fatEntries[nextCluster];
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}
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return clusters.ToArray();
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}
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ErrorNumber GetFileEntry(string path, out CompleteDirectoryEntry entry)
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{
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entry = null;
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string cutPath = path.StartsWith('/') ? path.Substring(1).ToLower(_cultureInfo) : path.ToLower(_cultureInfo);
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string[] pieces = cutPath.Split(new[]
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{
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'/'
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}, StringSplitOptions.RemoveEmptyEntries);
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if(pieces.Length == 0)
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return ErrorNumber.InvalidArgument;
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var parentPath = string.Join("/", pieces, 0, pieces.Length - 1);
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if(!_directoryCache.TryGetValue(parentPath, out _))
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{
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ErrorNumber err = ReadDir(parentPath, out _);
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if(err != ErrorNumber.NoError)
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return err;
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}
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Dictionary<string, CompleteDirectoryEntry> parent;
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if(pieces.Length == 1)
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parent = _rootDirectoryCache;
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else if(!_directoryCache.TryGetValue(parentPath, out parent))
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return ErrorNumber.InvalidArgument;
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KeyValuePair<string, CompleteDirectoryEntry> dirent =
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parent.FirstOrDefault(t => t.Key.ToLower(_cultureInfo) == pieces[^1]);
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if(string.IsNullOrEmpty(dirent.Key))
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return ErrorNumber.NoSuchFile;
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entry = dirent.Value;
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return ErrorNumber.NoError;
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}
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byte LfnChecksum(byte[] name, byte[] extension)
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{
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byte sum = 0;
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for(var i = 0; i < 8; i++)
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sum = (byte)(((sum & 1) << 7) + (sum >> 1) + name[i]);
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for(var i = 0; i < 3; i++)
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sum = (byte)(((sum & 1) << 7) + (sum >> 1) + extension[i]);
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return sum;
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}
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} |