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256 lines
9.7 KiB
C#
256 lines
9.7 KiB
C#
// /***************************************************************************
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// The Disc Image Chef
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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 © 2011-2019 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 DiscImageChef.CommonTypes.Structs;
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using FileAttributes = DiscImageChef.CommonTypes.Structs.FileAttributes;
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namespace DiscImageChef.Filesystems.FAT
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{
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public partial class FAT
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{
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public Errno MapBlock(string path, long fileBlock, out long deviceBlock)
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{
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deviceBlock = 0;
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if(!mounted) return Errno.AccessDenied;
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Errno err = Stat(path, out FileEntryInfo stat);
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if(err != Errno.NoError) return err;
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if(stat.Attributes.HasFlag(FileAttributes.Directory) && !debug) return Errno.IsDirectory;
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uint[] clusters = GetClusters((uint)stat.Inode);
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if(fileBlock >= clusters.Length) return Errno.InvalidArgument;
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deviceBlock = (long)(firstClusterSector + clusters[fileBlock] * sectorsPerCluster);
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return Errno.NoError;
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}
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public Errno GetAttributes(string path, out FileAttributes attributes)
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{
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attributes = new FileAttributes();
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if(!mounted) return Errno.AccessDenied;
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Errno err = Stat(path, out FileEntryInfo stat);
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if(err != Errno.NoError) return err;
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attributes = stat.Attributes;
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return Errno.NoError;
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}
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public Errno Read(string path, long offset, long size, ref byte[] buf)
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{
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if(!mounted) return Errno.AccessDenied;
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Errno err = Stat(path, out FileEntryInfo stat);
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if(err != Errno.NoError) return err;
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if(stat.Attributes.HasFlag(FileAttributes.Directory) && !debug) return Errno.IsDirectory;
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if(offset >= stat.Length) return Errno.InvalidArgument;
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if(size + offset >= stat.Length) size = stat.Length - offset;
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uint[] clusters = GetClusters((uint)stat.Inode);
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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) sizeInClusters++;
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MemoryStream ms = new MemoryStream();
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for(int i = 0; i < sizeInClusters; i++)
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{
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if(i + firstCluster >= clusters.Length) return Errno.InvalidArgument;
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byte[] buffer = image.ReadSectors(firstClusterSector + clusters[i + firstCluster] * sectorsPerCluster,
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sectorsPerCluster);
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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 Errno.NoError;
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}
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public Errno Stat(string path, out FileEntryInfo stat)
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{
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stat = null;
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if(!mounted) return Errno.AccessDenied;
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Errno err = GetFileEntry(path, out CompleteDirectoryEntry completeEntry);
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if(err != Errno.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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CreationTime = DateHandlers.DosToDateTime(entry.cdate, entry.ctime)
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};
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if(@namespace != Namespace.Human)
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{
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stat.LastWriteTime = DateHandlers.DosToDateTime(entry.mdate, entry.mtime);
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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) 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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stat.Blocks = fat32
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? GetClusters((uint)((entry.ea_handle << 16) + entry.start_cluster)).Length
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: GetClusters(entry.start_cluster).Length;
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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 Errno.NoError;
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}
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uint[] GetClusters(uint startCluster)
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{
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if(startCluster == 0) return null;
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if(startCluster >= XmlFsType.Clusters) return null;
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List<uint> clusters = new List<uint>();
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uint nextCluster = startCluster;
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ulong nextSector = nextCluster / fatEntriesPerSector + fatFirstSector + (useFirstFat ? 0 : sectorsPerFat);
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int nextEntry = (int)(nextCluster % fatEntriesPerSector);
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ulong currentSector = nextSector;
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byte[] fatData = image.ReadSector(currentSector);
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if(fat32)
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while((nextCluster & FAT32_MASK) > 0 && (nextCluster & FAT32_MASK) <= FAT32_FORMATTED)
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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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fatData = image.ReadSector(nextSector);
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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 +
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(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 && nextCluster <= FAT16_FORMATTED)
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{
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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 && nextCluster <= FAT12_FORMATTED)
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{
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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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Errno GetFileEntry(string path, out CompleteDirectoryEntry entry)
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{
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entry = null;
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string cutPath =
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path.StartsWith("/") ? path.Substring(1).ToLower(cultureInfo) : path.ToLower(cultureInfo);
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string[] pieces = cutPath.Split(new[] {'/'}, StringSplitOptions.RemoveEmptyEntries);
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if(pieces.Length == 0) return Errno.InvalidArgument;
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string 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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Errno err = ReadDir(parentPath, out _);
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if(err != Errno.NoError) return err;
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}
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Dictionary<string, CompleteDirectoryEntry> parent;
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if(pieces.Length == 1) parent = rootDirectoryCache;
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else if(!directoryCache.TryGetValue(parentPath, out parent)) return Errno.InvalidArgument;
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KeyValuePair<string, CompleteDirectoryEntry> dirent =
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parent.FirstOrDefault(t => t.Key.ToLower(cultureInfo) == pieces[pieces.Length - 1]);
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if(string.IsNullOrEmpty(dirent.Key)) return Errno.NoSuchFile;
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entry = dirent.Value;
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return Errno.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(int i = 0; i < 8; i++) sum = (byte)(((sum & 1) << 7) + (sum >> 1) + name[i]);
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for(int 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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}
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} |