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https://github.com/aaru-dps/Aaru.git
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323 lines
10 KiB
C#
323 lines
10 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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// --[ 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 © 2011-2025 Natalia Portillo
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// ****************************************************************************/
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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.Interfaces;
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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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namespace Aaru.Filesystems;
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public sealed partial class FAT
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{
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uint[] GetClusters(uint startCluster)
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{
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if(startCluster == 0) return [];
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if(startCluster >= Metadata.Clusters) return null;
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List<uint> clusters = [];
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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, false, out byte[] fatData, out _);
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if(errno != ErrorNumber.NoError) return null;
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if(_fat32)
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{
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while((nextCluster & FAT32_MASK) > 0 && (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, false, out fatData, out _);
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if(errno != ErrorNumber.NoError) 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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}
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else if(_fat16)
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{
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while(nextCluster is > 0 and <= FAT16_RESERVED)
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{
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if(nextCluster >= _fatEntries.Length) break;
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clusters.Add(nextCluster);
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nextCluster = _fatEntries[nextCluster];
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}
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}
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else
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{
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while(nextCluster is > 0 and <= FAT12_RESERVED)
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{
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if(nextCluster >= _fatEntries.Length) break;
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clusters.Add(nextCluster);
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nextCluster = _fatEntries[nextCluster];
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}
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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[1..].ToLower(_cultureInfo) : path.ToLower(_cultureInfo);
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string[] pieces = cutPath.Split(['/'], StringSplitOptions.RemoveEmptyEntries);
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if(pieces.Length == 0) 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 = OpenDir(parentPath, out IDirNode node);
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if(err != ErrorNumber.NoError) return err;
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CloseDir(node);
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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)) 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)) 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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static 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++) sum = (byte)(((sum & 1) << 7) + (sum >> 1) + name[i]);
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for(var i = 0; i < 3; i++) sum = (byte)(((sum & 1) << 7) + (sum >> 1) + extension[i]);
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return sum;
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}
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#region IReadOnlyFilesystem Members
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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) return ErrorNumber.AccessDenied;
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ErrorNumber err = Stat(path, out FileEntryInfo stat);
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if(err != ErrorNumber.NoError) 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 OpenFile(string path, out IFileNode node)
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{
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node = null;
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if(!_mounted) return ErrorNumber.AccessDenied;
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ErrorNumber err = Stat(path, out FileEntryInfo stat);
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if(err != ErrorNumber.NoError) return err;
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if(stat.Attributes.HasFlag(FileAttributes.Directory) && !_debug) return ErrorNumber.IsDirectory;
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uint[] clusters = GetClusters((uint)stat.Inode);
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if(clusters is null) return ErrorNumber.InvalidArgument;
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node = new FatFileNode
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{
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Path = path,
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Length = stat.Length,
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Offset = 0,
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Clusters = clusters
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};
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return ErrorNumber.NoError;
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}
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/// <inheritdoc />
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public ErrorNumber CloseFile(IFileNode node)
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{
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if(!_mounted) return ErrorNumber.AccessDenied;
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if(node is not FatFileNode mynode) return ErrorNumber.InvalidArgument;
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mynode.Clusters = null;
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return ErrorNumber.NoError;
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}
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/// <inheritdoc />
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public ErrorNumber ReadFile(IFileNode node, long length, byte[] buffer, out long read)
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{
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read = 0;
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if(!_mounted) return ErrorNumber.AccessDenied;
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if(buffer is null || buffer.Length < length) return ErrorNumber.InvalidArgument;
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if(node is not FatFileNode mynode) return ErrorNumber.InvalidArgument;
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read = length;
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if(length + mynode.Offset >= mynode.Length) read = mynode.Length - mynode.Offset;
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long firstCluster = mynode.Offset / _bytesPerCluster;
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long offsetInCluster = mynode.Offset % _bytesPerCluster;
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long sizeInClusters = (read + offsetInCluster) / _bytesPerCluster;
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if((read + offsetInCluster) % _bytesPerCluster > 0) 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 >= mynode.Clusters.Length) return ErrorNumber.InvalidArgument;
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ErrorNumber errno =
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_image.ReadSectors(_firstClusterSector + mynode.Clusters[i + firstCluster] * _sectorsPerCluster,
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false,
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_sectorsPerCluster,
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out byte[] buf,
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out _);
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if(errno != ErrorNumber.NoError) return errno;
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ms.Write(buf, 0, buf.Length);
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}
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ms.Position = offsetInCluster;
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ms.EnsureRead(buffer, 0, (int)read);
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mynode.Offset += read;
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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) return ErrorNumber.AccessDenied;
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ErrorNumber err = GetFileEntry(path, out CompleteDirectoryEntry completeEntry);
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if(err != ErrorNumber.NoError) 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 || entry.ctime > 0) 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 || entry.mtime > 0)
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stat.LastWriteTime = DateHandlers.DosToDateTime(entry.mdate, entry.mtime);
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if(entry.ctime_ms > 0) stat.CreationTime = stat.CreationTime?.AddMilliseconds(entry.ctime_ms * 10);
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}
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if(entry.size % _bytesPerCluster > 0) 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 || entry.start_cluster > 0)
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{
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stat.Blocks = _fat32
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? 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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}
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stat.Length = stat.Blocks * stat.BlockSize;
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}
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if(entry.attributes.HasFlag(FatAttributes.ReadOnly)) stat.Attributes |= FileAttributes.ReadOnly;
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if(entry.attributes.HasFlag(FatAttributes.Hidden)) stat.Attributes |= FileAttributes.Hidden;
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if(entry.attributes.HasFlag(FatAttributes.System)) stat.Attributes |= FileAttributes.System;
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if(entry.attributes.HasFlag(FatAttributes.Archive)) stat.Attributes |= FileAttributes.Archive;
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if(entry.attributes.HasFlag(FatAttributes.Device)) stat.Attributes |= FileAttributes.Device;
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return ErrorNumber.NoError;
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}
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#endregion
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} |