Aaru/Aaru.Filesystems/XFS.cs

// /***************************************************************************
// Aaru Data Preservation Suite
// ----------------------------------------------------------------------------
//
// Filename       : XFS.cs
// Author(s)      : Natalia Portillo <claunia@claunia.com>
//
// Component      : XFS filesystem plugin.
//
// --[ Description ] ----------------------------------------------------------
//
//     Identifies the XFS filesystem and shows information.
//
// --[ 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 © 2011-2022 Natalia Portillo
// ****************************************************************************/

using System;
using System.Runtime.InteropServices;
using System.Text;
using Aaru.CommonTypes;
using Aaru.CommonTypes.Enums;
using Aaru.CommonTypes.Interfaces;
using Aaru.Console;
using Aaru.Helpers;
using Schemas;
using Marshal = Aaru.Helpers.Marshal;

namespace Aaru.Filesystems;

/// <inheritdoc />
/// <summary>Implements detection of SGI's XFS</summary>
public sealed class XFS : IFilesystem
{
    const uint XFS_MAGIC = 0x58465342;

    const string FS_TYPE = "xfs";

    /// <inheritdoc />
    public FileSystemType XmlFsType { get; private set; }
    /// <inheritdoc />
    public Encoding Encoding { get; private set; }
    /// <inheritdoc />
    public string Name => Localization.XFS_Name;
    /// <inheritdoc />
    public Guid Id => new("1D8CD8B8-27E6-410F-9973-D16409225FBA");
    /// <inheritdoc />
    public string Author => Authors.NataliaPortillo;

    /// <inheritdoc />
    public bool Identify(IMediaImage imagePlugin, Partition partition)
    {
        if(imagePlugin.Info.SectorSize < 512)
            return false;

        // Misaligned
        if(imagePlugin.Info.XmlMediaType == XmlMediaType.OpticalDisc)
        {
            uint sbSize = (uint)((Marshal.SizeOf<Superblock>() + 0x400) / imagePlugin.Info.SectorSize);

            if((Marshal.SizeOf<Superblock>() + 0x400) % imagePlugin.Info.SectorSize != 0)
                sbSize++;

            ErrorNumber errno = imagePlugin.ReadSectors(partition.Start, sbSize, out byte[] sector);

            if(errno != ErrorNumber.NoError)
                return false;

            if(sector.Length < Marshal.SizeOf<Superblock>())
                return false;

            byte[] sbpiece = new byte[Marshal.SizeOf<Superblock>()];

            foreach(int location in new[]
                    {
                        0, 0x200, 0x400
                    })
            {
                Array.Copy(sector, location, sbpiece, 0, Marshal.SizeOf<Superblock>());

                Superblock xfsSb = Marshal.ByteArrayToStructureBigEndian<Superblock>(sbpiece);

                AaruConsole.DebugWriteLine("XFS plugin", Localization.magic_at_0_X3_equals_1_expected_2, location,
                                           xfsSb.magicnum, XFS_MAGIC);

                if(xfsSb.magicnum == XFS_MAGIC)
                    return true;
            }
        }
        else
            foreach(int i in new[]
                    {
                        0, 1, 2
                    })
            {
                ulong location = (ulong)i;

                uint sbSize = (uint)(Marshal.SizeOf<Superblock>() / imagePlugin.Info.SectorSize);

                if(Marshal.SizeOf<Superblock>() % imagePlugin.Info.SectorSize != 0)
                    sbSize++;

                ErrorNumber errno = imagePlugin.ReadSectors(partition.Start + location, sbSize, out byte[] sector);

                if(errno != ErrorNumber.NoError)
                    continue;

                if(sector.Length < Marshal.SizeOf<Superblock>())
                    return false;

                Superblock xfsSb = Marshal.ByteArrayToStructureBigEndian<Superblock>(sector);

                AaruConsole.DebugWriteLine("XFS plugin", Localization.magic_at_0_equals_1_expected_2, location,
                                           xfsSb.magicnum, XFS_MAGIC);

                if(xfsSb.magicnum == XFS_MAGIC)
                    return true;
            }

        return false;
    }

    /// <inheritdoc />
    public void GetInformation(IMediaImage imagePlugin, Partition partition, out string information, Encoding encoding)
    {
        Encoding    = encoding ?? Encoding.GetEncoding("iso-8859-15");
        information = "";

        if(imagePlugin.Info.SectorSize < 512)
            return;

        var xfsSb = new Superblock();

        // Misaligned
        if(imagePlugin.Info.XmlMediaType == XmlMediaType.OpticalDisc)
        {
            uint sbSize = (uint)((Marshal.SizeOf<Superblock>() + 0x400) / imagePlugin.Info.SectorSize);

            if((Marshal.SizeOf<Superblock>() + 0x400) % imagePlugin.Info.SectorSize != 0)
                sbSize++;

            ErrorNumber errno = imagePlugin.ReadSectors(partition.Start, sbSize, out byte[] sector);

            if(errno         != ErrorNumber.NoError ||
               sector.Length < Marshal.SizeOf<Superblock>())
                return;

            byte[] sbpiece = new byte[Marshal.SizeOf<Superblock>()];

            foreach(int location in new[]
                    {
                        0, 0x200, 0x400
                    })
            {
                Array.Copy(sector, location, sbpiece, 0, Marshal.SizeOf<Superblock>());

                xfsSb = Marshal.ByteArrayToStructureBigEndian<Superblock>(sbpiece);

                AaruConsole.DebugWriteLine("XFS plugin", Localization.magic_at_0_X3_equals_1_expected_2, location,
                                           xfsSb.magicnum, XFS_MAGIC);

                if(xfsSb.magicnum == XFS_MAGIC)
                    break;
            }
        }
        else
            foreach(int i in new[]
                    {
                        0, 1, 2
                    })
            {
                ulong location = (ulong)i;
                uint  sbSize   = (uint)(Marshal.SizeOf<Superblock>() / imagePlugin.Info.SectorSize);

                if(Marshal.SizeOf<Superblock>() % imagePlugin.Info.SectorSize != 0)
                    sbSize++;

                ErrorNumber errno = imagePlugin.ReadSectors(partition.Start + location, sbSize, out byte[] sector);

                if(errno         != ErrorNumber.NoError ||
                   sector.Length < Marshal.SizeOf<Superblock>())
                    return;

                xfsSb = Marshal.ByteArrayToStructureBigEndian<Superblock>(sector);

                AaruConsole.DebugWriteLine("XFS plugin", Localization.magic_at_0_equals_1_expected_2, location,
                                           xfsSb.magicnum, XFS_MAGIC);

                if(xfsSb.magicnum == XFS_MAGIC)
                    break;
            }

        if(xfsSb.magicnum != XFS_MAGIC)
            return;

        var sb = new StringBuilder();

        sb.AppendLine(Localization.XFS_filesystem);
        sb.AppendFormat(Localization.Filesystem_version_0, xfsSb.version & 0xF).AppendLine();
        sb.AppendFormat(Localization._0_bytes_per_sector, xfsSb.sectsize).AppendLine();
        sb.AppendFormat(Localization._0_bytes_per_block, xfsSb.blocksize).AppendLine();
        sb.AppendFormat(Localization._0_bytes_per_inode, xfsSb.inodesize).AppendLine();
        sb.AppendFormat(Localization._0_data_blocks_in_volume_1_free, xfsSb.dblocks, xfsSb.fdblocks).AppendLine();
        sb.AppendFormat(Localization._0_blocks_per_allocation_group, xfsSb.agblocks).AppendLine();
        sb.AppendFormat(Localization._0_allocation_groups_in_volume, xfsSb.agcount).AppendLine();
        sb.AppendFormat(Localization._0_inodes_in_volume_1_free, xfsSb.icount, xfsSb.ifree).AppendLine();

        if(xfsSb.inprogress > 0)
            sb.AppendLine(Localization.fsck_in_progress);

        sb.AppendFormat(Localization.Volume_name_0, StringHandlers.CToString(xfsSb.fname, Encoding)).AppendLine();
        sb.AppendFormat(Localization.Volume_UUID_0, xfsSb.uuid).AppendLine();

        information = sb.ToString();

        XmlFsType = new FileSystemType
        {
            Type                  = FS_TYPE,
            ClusterSize           = xfsSb.blocksize,
            Clusters              = xfsSb.dblocks,
            FreeClusters          = xfsSb.fdblocks,
            FreeClustersSpecified = true,
            Files                 = xfsSb.icount - xfsSb.ifree,
            FilesSpecified        = true,
            Dirty                 = xfsSb.inprogress > 0,
            VolumeName            = StringHandlers.CToString(xfsSb.fname, Encoding),
            VolumeSerial          = xfsSb.uuid.ToString()
        };
    }

    [StructLayout(LayoutKind.Sequential, Pack = 1)]
    readonly struct Superblock
    {
        public readonly uint   magicnum;
        public readonly uint   blocksize;
        public readonly ulong  dblocks;
        public readonly ulong  rblocks;
        public readonly ulong  rextents;
        public readonly Guid   uuid;
        public readonly ulong  logstat;
        public readonly ulong  rootino;
        public readonly ulong  rbmino;
        public readonly ulong  rsumino;
        public readonly uint   rextsize;
        public readonly uint   agblocks;
        public readonly uint   agcount;
        public readonly uint   rbmblocks;
        public readonly uint   logblocks;
        public readonly ushort version;
        public readonly ushort sectsize;
        public readonly ushort inodesize;
        public readonly ushort inopblock;
        [MarshalAs(UnmanagedType.ByValArray, SizeConst = 12)]
        public readonly byte[] fname;
        public readonly byte   blocklog;
        public readonly byte   sectlog;
        public readonly byte   inodelog;
        public readonly byte   inopblog;
        public readonly byte   agblklog;
        public readonly byte   rextslog;
        public readonly byte   inprogress;
        public readonly byte   imax_pct;
        public readonly ulong  icount;
        public readonly ulong  ifree;
        public readonly ulong  fdblocks;
        public readonly ulong  frextents;
        public readonly ulong  uquotino;
        public readonly ulong  gquotino;
        public readonly ushort qflags;
        public readonly byte   flags;
        public readonly byte   shared_vn;
        public readonly ulong  inoalignmt;
        public readonly ulong  unit;
        public readonly ulong  width;
        public readonly byte   dirblklog;
        public readonly byte   logsectlog;
        public readonly ushort logsectsize;
        public readonly uint   logsunit;
        public readonly uint   features2;
        public readonly uint   bad_features2;
        public readonly uint   features_compat;
        public readonly uint   features_ro_compat;
        public readonly uint   features_incompat;
        public readonly uint   features_log_incompat;

        // This field is little-endian while rest of superblock is big-endian
        public readonly uint  crc;
        public readonly uint  spino_align;
        public readonly ulong pquotino;
        public readonly ulong lsn;
        public readonly Guid  meta_uuid;
    }
}