Files
Aaru/Aaru.Partitions/Acorn.cs

397 lines
13 KiB
C#

// /***************************************************************************
// Aaru Data Preservation Suite
// ----------------------------------------------------------------------------
//
// Filename : Acorn.cs
// Author(s) : Natalia Portillo <claunia@claunia.com>
//
// Component : Partitioning scheme plugins.
//
// --[ Description ] ----------------------------------------------------------
//
// Manages Acorn FileCore partitions.
//
// --[ 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 System.Runtime.InteropServices;
using System.Text;
using Aaru.CommonTypes;
using Aaru.CommonTypes.Enums;
using Aaru.CommonTypes.Interfaces;
using Aaru.Helpers;
using Marshal = Aaru.Helpers.Marshal;
namespace Aaru.Partitions;
/// <inheritdoc />
/// <summary>Implements decoding of Acorn partitions</summary>
public sealed class Acorn : IPartition
{
const ulong ADFS_SB_POS = 0xC00;
const uint LINUX_MAGIC = 0xDEAFA1DE;
const uint SWAP_MAGIC = 0xDEAFAB1E;
const uint RISCIX_MAGIC = 0x4A657320;
const uint TYPE_LINUX = 9;
const uint TYPE_RISCIX_MFM = 1;
const uint TYPE_RISCIX_SCSI = 2;
const uint TYPE_MASK = 15;
readonly byte[] _linuxIcsMagic = "LinuxPart"u8.ToArray();
static void GetFileCorePartitions(IMediaImage imagePlugin, List<Partition> partitions, ulong sectorOffset,
ref ulong counter)
{
// RISC OS always checks for the partition on 0. Afaik no emulator chains it.
if(sectorOffset != 0) return;
ulong sbSector;
if(imagePlugin.Info.SectorSize > ADFS_SB_POS)
sbSector = 0;
else
sbSector = ADFS_SB_POS / imagePlugin.Info.SectorSize;
ErrorNumber errno = imagePlugin.ReadSector(sbSector, false, out byte[] sector, out _);
if(errno != ErrorNumber.NoError || sector.Length < 512) return;
AcornBootBlock bootBlock = Marshal.ByteArrayToStructureLittleEndian<AcornBootBlock>(sector);
var checksum = 0;
for(var i = 0; i < 0x1FF; i++) checksum = (checksum & 0xFF) + (checksum >> 8) + sector[i];
int heads = bootBlock.discRecord.heads + (bootBlock.discRecord.lowsector >> 6 & 1);
int secCyl = bootBlock.discRecord.spt * heads;
int mapSector = bootBlock.startCylinder * secCyl;
if((ulong)mapSector >= imagePlugin.Info.Sectors) return;
errno = imagePlugin.ReadSector((ulong)mapSector, false, out byte[] map, out _);
if(errno != ErrorNumber.NoError) return;
if(checksum == bootBlock.checksum)
{
var part = new Partition
{
Size = (ulong)bootBlock.discRecord.disc_size_high * 0x100000000 + bootBlock.discRecord.disc_size,
Length = ((ulong)bootBlock.discRecord.disc_size_high * 0x100000000 + bootBlock.discRecord.disc_size) /
imagePlugin.Info.SectorSize,
Type = Localization.Filecore,
Name = StringHandlers.CToString(bootBlock.discRecord.disc_name, Encoding.GetEncoding("iso-8859-1"))
};
if(part.Size > 0)
{
partitions.Add(part);
counter++;
}
}
switch(bootBlock.flags & TYPE_MASK)
{
case TYPE_LINUX:
{
LinuxTable table = Marshal.ByteArrayToStructureLittleEndian<LinuxTable>(map);
foreach(LinuxEntry entry in table.entries)
{
var part = new Partition
{
Start = (ulong)(mapSector + entry.start),
Size = entry.size,
Length = (ulong)(entry.size * sector.Length),
Sequence = counter,
Scheme = "Filecore/Linux",
Type = entry.magic switch
{
LINUX_MAGIC => Localization.Linux,
SWAP_MAGIC => Localization.Linux_swap,
_ => Localization.Unknown_partition_type
}
};
part.Offset = part.Start * (ulong)sector.Length;
if(entry.magic != LINUX_MAGIC && entry.magic != SWAP_MAGIC) continue;
partitions.Add(part);
counter++;
}
break;
}
case TYPE_RISCIX_MFM:
case TYPE_RISCIX_SCSI:
{
RiscIxTable table = Marshal.ByteArrayToStructureLittleEndian<RiscIxTable>(map);
if(table.magic == RISCIX_MAGIC)
{
foreach(RiscIxEntry entry in table.partitions)
{
var part = new Partition
{
Start = (ulong)(mapSector + entry.start),
Size = entry.length,
Length = (ulong)(entry.length * sector.Length),
Name = StringHandlers.CToString(entry.name, Encoding.GetEncoding("iso-8859-1")),
Sequence = counter,
Scheme = "Filecore/RISCiX",
Type = Localization.Unknown_partition_type
};
part.Offset = part.Start * (ulong)sector.Length;
if(entry.length <= 0) continue;
partitions.Add(part);
counter++;
}
}
break;
}
}
}
void GetIcsPartitions(IMediaImage imagePlugin, List<Partition> partitions, ulong sectorOffset, ref ulong counter)
{
// RISC OS always checks for the partition on 0. Afaik no emulator chains it.
if(sectorOffset != 0) return;
ErrorNumber errno = imagePlugin.ReadSector(0, false, out byte[] sector, out _);
if(errno != ErrorNumber.NoError || sector.Length < 512) return;
uint icsSum = 0x50617274;
for(var i = 0; i < 508; i++) icsSum += sector[i];
var discCheck = BitConverter.ToUInt32(sector, 508);
if(icsSum != discCheck) return;
IcsTable table = Marshal.ByteArrayToStructureLittleEndian<IcsTable>(sector);
foreach(IcsEntry entry in table.entries.Where(static entry => entry.size != 0))
{
// FileCore partition
Partition part;
if(entry.size > 0)
{
part = new Partition
{
Start = entry.start,
Length = (ulong)entry.size,
Size = (ulong)(entry.size * sector.Length),
Type = Localization.Filecore,
Sequence = counter,
Scheme = "ICS"
};
part.Offset = part.Start * (ulong)sector.Length;
counter++;
partitions.Add(part);
continue;
}
// Negative size means Linux partition, first sector needs to be read
errno = imagePlugin.ReadSector(entry.start, false, out sector, out _);
if(errno != ErrorNumber.NoError) continue;
if(_linuxIcsMagic.Where((t, i) => t != sector[i]).Any()) continue;
part = new Partition
{
Start = entry.start,
Length = (ulong)(entry.size * -1),
Size = (ulong)(entry.size * -1 * sector.Length),
Type = sector[9] == 'N'
? Localization.Linux
: sector[9] == 'S'
? Localization.Linux_swap
: Localization.Unknown_partition_type,
Sequence = counter,
Scheme = "ICS"
};
part.Offset = part.Start * (ulong)sector.Length;
counter++;
partitions.Add(part);
}
}
#region Nested type: AcornBootBlock
[StructLayout(LayoutKind.Sequential, Pack = 1)]
struct AcornBootBlock
{
[MarshalAs(UnmanagedType.ByValArray, SizeConst = 0x1C0)]
public readonly byte[] spare;
public readonly DiscRecord discRecord;
public readonly byte flags;
public readonly ushort startCylinder;
public readonly byte checksum;
}
#endregion
#region Nested type: DiscRecord
[StructLayout(LayoutKind.Sequential)]
struct DiscRecord
{
public readonly byte log2secsize;
public readonly byte spt;
public readonly byte heads;
public readonly byte density;
public readonly byte idlen;
public readonly byte log2bpmb;
public readonly byte skew;
public readonly byte bootoption;
public readonly byte lowsector;
public readonly byte nzones;
public readonly ushort zone_spare;
public readonly uint root;
public readonly uint disc_size;
public readonly ushort disc_id;
[MarshalAs(UnmanagedType.ByValArray, SizeConst = 10)]
public readonly byte[] disc_name;
public readonly uint disc_type;
public readonly uint disc_size_high;
public readonly byte flags;
public readonly byte nzones_high;
public readonly uint format_version;
public readonly uint root_size;
[MarshalAs(UnmanagedType.ByValArray, SizeConst = 8)]
public readonly byte[] reserved;
}
#endregion
#region Nested type: IcsEntry
[StructLayout(LayoutKind.Sequential, Pack = 1)]
struct IcsEntry
{
public readonly uint start;
public readonly int size;
}
#endregion
#region Nested type: IcsTable
[StructLayout(LayoutKind.Sequential, Pack = 1)]
struct IcsTable
{
[MarshalAs(UnmanagedType.ByValArray, SizeConst = 16)]
public readonly IcsEntry[] entries;
}
#endregion
#region Nested type: LinuxEntry
[StructLayout(LayoutKind.Sequential, Pack = 1)]
struct LinuxEntry
{
public readonly uint magic;
public readonly uint start;
public readonly uint size;
}
#endregion
#region Nested type: LinuxTable
[StructLayout(LayoutKind.Sequential, Pack = 1)]
struct LinuxTable
{
[MarshalAs(UnmanagedType.ByValArray, SizeConst = 42)]
public readonly LinuxEntry[] entries;
[MarshalAs(UnmanagedType.ByValArray, SizeConst = 8)]
public readonly byte[] padding;
}
#endregion
#region Nested type: RiscIxEntry
[StructLayout(LayoutKind.Sequential, Pack = 1)]
struct RiscIxEntry
{
public readonly uint start;
public readonly uint length;
public readonly uint one;
[MarshalAs(UnmanagedType.ByValArray, SizeConst = 16)]
public readonly byte[] name;
}
#endregion
#region Nested type: RiscIxTable
[StructLayout(LayoutKind.Sequential, Pack = 1)]
struct RiscIxTable
{
public readonly uint magic;
public readonly uint date;
[MarshalAs(UnmanagedType.ByValArray, SizeConst = 8)]
public readonly RiscIxEntry[] partitions;
}
#endregion
#region IPartition Members
/// <inheritdoc />
public string Name => Localization.Acorn_Name;
/// <inheritdoc />
public Guid Id => new("A7C8FEBE-8D00-4933-B9F3-42184C8BA808");
/// <inheritdoc />
public string Author => Authors.NATALIA_PORTILLO;
/// <inheritdoc />
public bool GetInformation(IMediaImage imagePlugin, out List<Partition> partitions, ulong sectorOffset)
{
partitions = [];
ulong counter = 0;
GetFileCorePartitions(imagePlugin, partitions, sectorOffset, ref counter);
GetIcsPartitions(imagePlugin, partitions, sectorOffset, ref counter);
return partitions.Count != 0;
}
#endregion
}