Files
Aaru/Aaru.Filesystems/LisaFS/Dir.cs
2025-08-14 15:51:32 +01:00

398 lines
14 KiB
C#

// /***************************************************************************
// Aaru Data Preservation Suite
// ----------------------------------------------------------------------------
//
// Filename : Dir.cs
// Author(s) : Natalia Portillo <claunia@claunia.com>
//
// Component : Apple Lisa filesystem plugin.
//
// --[ Description ] ----------------------------------------------------------
//
// Methods to handle Apple Lisa filesystem catalogs (aka directories).
//
// --[ License ] --------------------------------------------------------------
//
// This library is free software; you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as
// published by the Free Software Foundation; either version 2.1 of the
// License, or (at your option) any later version.
//
// This library is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, see <http://www.gnu.org/licenses/>.
//
// ----------------------------------------------------------------------------
// Copyright © 2011-2025 Natalia Portillo
// ****************************************************************************/
using System;
using System.Collections.Generic;
using System.Linq;
using Aaru.CommonTypes.Enums;
using Aaru.CommonTypes.Interfaces;
using Aaru.CommonTypes.Structs;
using Aaru.Decoders;
using Aaru.Helpers;
using FileAttributes = Aaru.CommonTypes.Structs.FileAttributes;
namespace Aaru.Filesystems;
public sealed partial class LisaFS
{
#region IReadOnlyFilesystem Members
/// <inheritdoc />
public ErrorNumber ReadLink(string path, out string dest)
{
dest = null;
// LisaFS does not support symbolic links (afaik)
return ErrorNumber.NotSupported;
}
/// <inheritdoc />
public ErrorNumber OpenDir(string path, out IDirNode node)
{
node = null;
ErrorNumber error = LookupFileId(path, out short fileId, out bool isDir);
if(error != ErrorNumber.NoError) return error;
if(!isDir) return ErrorNumber.NotDirectory;
/*List<CatalogEntry> catalog;
error = ReadCatalog(fileId, out catalog);
if(error != ErrorNumber.NoError)
return error;*/
ReadDir(fileId, out List<string> contents);
// On debug add system files as readable files
// Syntax similar to NTFS
if(_debug && fileId == DIRID_ROOT)
{
contents.Add("$MDDF");
contents.Add("$Boot");
contents.Add("$Loader");
contents.Add("$Bitmap");
contents.Add("$S-Record");
contents.Add("$");
}
contents.Sort();
node = new LisaDirNode
{
Path = path,
Contents = contents.ToArray(),
Position = 0
};
return ErrorNumber.NoError;
}
/// <inheritdoc />
public ErrorNumber ReadDir(IDirNode node, out string filename)
{
filename = null;
if(!_mounted) return ErrorNumber.AccessDenied;
if(node is not LisaDirNode mynode) return ErrorNumber.InvalidArgument;
if(mynode.Position < 0) return ErrorNumber.InvalidArgument;
if(mynode.Position >= mynode.Contents.Length) return ErrorNumber.NoError;
filename = mynode.Contents[mynode.Position++];
return ErrorNumber.NoError;
}
/// <inheritdoc />
public ErrorNumber CloseDir(IDirNode node)
{
if(node is not LisaDirNode mynode) return ErrorNumber.InvalidArgument;
mynode.Position = -1;
mynode.Contents = null;
return ErrorNumber.NoError;
}
#endregion
void ReadDir(short dirId, out List<string> contents) =>
// Do same trick as Mac OS X, replace filesystem '/' with '-',
// as '-' is the path separator in Lisa OS
contents = (from entry in _catalogCache
where entry.parentID == dirId
select StringHandlers.CToString(entry.filename, _encoding).Replace('/', '-')).ToList();
/// <summary>Reads, interprets and caches the Catalog File</summary>
ErrorNumber ReadCatalog()
{
ErrorNumber errno;
if(!_mounted) return ErrorNumber.AccessDenied;
_catalogCache = [];
// Do differently for V1 and V2
if(_mddf.fsversion is LISA_V2 or LISA_V1)
{
ErrorNumber error = ReadFile((short)FILEID_CATALOG, out byte[] buf);
if(error != ErrorNumber.NoError) return error;
int offset = 0;
List<CatalogEntryV2> catalogV2 = [];
// For each entry on the catalog
while(offset + 54 < buf.Length)
{
var entV2 = new CatalogEntryV2
{
filenameLen = buf[offset],
filename = new byte[E_NAME],
unknown1 = buf[offset + 0x21],
fileType = buf[offset + 0x22],
unknown2 = buf[offset + 0x23],
fileID = BigEndianBitConverter.ToInt16(buf, offset + 0x24),
unknown3 = new byte[16]
};
Array.Copy(buf, offset + 0x01, entV2.filename, 0, E_NAME);
Array.Copy(buf, offset + 0x26, entV2.unknown3, 0, 16);
offset += 54;
// Check that the entry is correct, not empty or garbage
if(entV2.filenameLen != 0 && entV2.filenameLen <= E_NAME && entV2.fileType != 0 && entV2.fileID > 0)
catalogV2.Add(entV2);
}
// Convert entries to V3 format
foreach(CatalogEntryV2 entV2 in catalogV2)
{
error = ReadExtentsFile(entV2.fileID, out ExtentFile ext);
if(error != ErrorNumber.NoError) continue;
var entV3 = new CatalogEntry
{
fileID = entV2.fileID,
filename = new byte[32],
fileType = entV2.fileType,
length = (int)_srecords[entV2.fileID].filesize,
dtc = ext.dtc,
dtm = ext.dtm
};
Array.Copy(entV2.filename, 0, entV3.filename, 0, entV2.filenameLen);
_catalogCache.Add(entV3);
}
return ErrorNumber.NoError;
}
byte[] firstCatalogBlock = null;
// Search for the first sector describing the catalog
// While root catalog is not stored in S-Records, probably rest are? (unchecked)
// If root catalog is not pointed in MDDF (unchecked) maybe it's always following S-Records File?
for(ulong i = 0; i < _device.Info.Sectors; i++)
{
errno = _device.ReadSectorTag(i, SectorTagType.AppleSectorTag, out byte[] tag);
if(errno != ErrorNumber.NoError) continue;
DecodeTag(tag, out LisaTag.PriamTag catTag);
if(catTag.FileId != FILEID_CATALOG || catTag.RelPage != 0) continue;
errno = _device.ReadSectors(i, 4, out firstCatalogBlock);
if(errno != ErrorNumber.NoError) return errno;
break;
}
// Catalog not found
if(firstCatalogBlock == null) return ErrorNumber.NoSuchFile;
ulong prevCatalogPointer = BigEndianBitConverter.ToUInt32(firstCatalogBlock, 0x7F6);
// Traverse double-linked list until first catalog block
while(prevCatalogPointer != 0xFFFFFFFF)
{
errno = _device.ReadSectorTag(prevCatalogPointer + _mddf.mddf_block + _volumePrefix,
SectorTagType.AppleSectorTag,
out byte[] tag);
if(errno != ErrorNumber.NoError) return errno;
DecodeTag(tag, out LisaTag.PriamTag prevTag);
if(prevTag.FileId != FILEID_CATALOG) return ErrorNumber.InvalidArgument;
errno = _device.ReadSectors(prevCatalogPointer + _mddf.mddf_block + _volumePrefix,
4,
out firstCatalogBlock);
if(errno != ErrorNumber.NoError) return errno;
prevCatalogPointer = BigEndianBitConverter.ToUInt32(firstCatalogBlock, 0x7F6);
}
ulong nextCatalogPointer = BigEndianBitConverter.ToUInt32(firstCatalogBlock, 0x7FA);
List<byte[]> catalogBlocks = [firstCatalogBlock];
// Traverse double-linked list to read full catalog
while(nextCatalogPointer != 0xFFFFFFFF)
{
errno = _device.ReadSectorTag(nextCatalogPointer + _mddf.mddf_block + _volumePrefix,
SectorTagType.AppleSectorTag,
out byte[] tag);
if(errno != ErrorNumber.NoError) return errno;
DecodeTag(tag, out LisaTag.PriamTag nextTag);
if(nextTag.FileId != FILEID_CATALOG) return ErrorNumber.InvalidArgument;
errno = _device.ReadSectors(nextCatalogPointer + _mddf.mddf_block + _volumePrefix,
4,
out byte[] nextCatalogBlock);
if(errno != ErrorNumber.NoError) return errno;
nextCatalogPointer = BigEndianBitConverter.ToUInt32(nextCatalogBlock, 0x7FA);
catalogBlocks.Add(nextCatalogBlock);
}
// Foreach catalog block
foreach(byte[] buf in catalogBlocks)
{
int offset = 0;
// Traverse all entries
while(offset + 64 <= buf.Length)
// Catalog block header
{
if(buf[offset + 0x24] == 0x08)
offset += 78;
// Maybe just garbage? Found in more than 1 disk
else if(buf[offset + 0x24] == 0x7C)
offset += 50;
// Apparently reserved to indicate end of catalog?
else if(buf[offset + 0x24] == 0xFF)
break;
// Normal entry
else if(buf[offset + 0x24] == 0x03 && buf[offset] == 0x24)
{
var entry = new CatalogEntry
{
marker = buf[offset],
parentID = BigEndianBitConverter.ToUInt16(buf, offset + 0x01),
filename = new byte[E_NAME],
terminator = buf[offset + 0x23],
fileType = buf[offset + 0x24],
unknown = buf[offset + 0x25],
fileID = BigEndianBitConverter.ToInt16(buf, offset + 0x26),
dtc = BigEndianBitConverter.ToUInt32(buf, offset + 0x28),
dtm = BigEndianBitConverter.ToUInt32(buf, offset + 0x2C),
length = BigEndianBitConverter.ToInt32(buf, offset + 0x30),
wasted = BigEndianBitConverter.ToInt32(buf, offset + 0x34),
tail = new byte[8]
};
Array.Copy(buf, offset + 0x03, entry.filename, 0, E_NAME);
Array.Copy(buf, offset + 0x38, entry.tail, 0, 8);
if(ReadExtentsFile(entry.fileID, out _) == ErrorNumber.NoError)
{
if(!_fileSizeCache.ContainsKey(entry.fileID))
{
_catalogCache.Add(entry);
_fileSizeCache.Add(entry.fileID, entry.length);
}
}
offset += 64;
}
// Subdirectory entry
else if(buf[offset + 0x24] == 0x01 && buf[offset] == 0x24)
{
var entry = new CatalogEntry
{
marker = buf[offset],
parentID = BigEndianBitConverter.ToUInt16(buf, offset + 0x01),
filename = new byte[E_NAME],
terminator = buf[offset + 0x23],
fileType = buf[offset + 0x24],
unknown = buf[offset + 0x25],
fileID = BigEndianBitConverter.ToInt16(buf, offset + 0x26),
dtc = BigEndianBitConverter.ToUInt32(buf, offset + 0x28),
dtm = BigEndianBitConverter.ToUInt32(buf, offset + 0x2C),
length = 0,
wasted = 0,
tail = null
};
Array.Copy(buf, offset + 0x03, entry.filename, 0, E_NAME);
if(!_directoryDtcCache.ContainsKey(entry.fileID))
_directoryDtcCache.Add(entry.fileID, DateHandlers.LisaToDateTime(entry.dtc));
_catalogCache.Add(entry);
offset += 48;
}
else
break;
}
}
return ErrorNumber.NoError;
}
ErrorNumber StatDir(short dirId, out FileEntryInfo stat)
{
stat = null;
if(!_mounted) return ErrorNumber.AccessDenied;
stat = new FileEntryInfo
{
Attributes = new FileAttributes(),
Inode = FILEID_CATALOG,
Mode = 0x16D,
Links = 0,
UID = 0,
GID = 0,
DeviceNo = 0,
Length = 0,
BlockSize = _mddf.datasize,
Blocks = 0
};
_directoryDtcCache.TryGetValue(dirId, out DateTime tmp);
stat.CreationTime = tmp;
return ErrorNumber.NoError;
}
}