Aaru/Aaru.Filesystems/JFS.cs

// /***************************************************************************
// Aaru Data Preservation Suite
// ----------------------------------------------------------------------------
//
// Filename       : JFS.cs
// Author(s)      : Natalia Portillo <claunia@claunia.com>
//
// Component      : IBM JFS filesystem plugin
//
// --[ Description ] ----------------------------------------------------------
//
//     Identifies the IBM JFS 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 © 2011-2020 Natalia Portillo
// ****************************************************************************/

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

namespace Aaru.Filesystems
{
    public class JFS : IFilesystem
    {
        const uint JFS_BOOT_BLOCKS_SIZE = 0x8000;
        const uint JFS_MAGIC            = 0x3153464A;

        public FileSystemType XmlFsType { get; private set; }
        public Encoding       Encoding  { get; private set; }
        public string         Name      => "JFS Plugin";
        public Guid           Id        => new Guid("D3BE2A41-8F28-4055-94DC-BB6C72A0E9C4");
        public string         Author    => "Natalia Portillo";

        public bool Identify(IMediaImage imagePlugin, Partition partition)
        {
            uint bootSectors = JFS_BOOT_BLOCKS_SIZE / imagePlugin.Info.SectorSize;
            if(partition.Start + bootSectors >= partition.End) return false;

            byte[] sector = imagePlugin.ReadSector(partition.Start + bootSectors);
            if(sector.Length < 512) return false;

            JfsSuperBlock jfsSb = Marshal.ByteArrayToStructureLittleEndian<JfsSuperBlock>(sector);

            return jfsSb.s_magic == JFS_MAGIC;
        }

        public void GetInformation(IMediaImage imagePlugin, Partition partition, out string information,
                                   Encoding    encoding)
        {
            Encoding    = encoding ?? Encoding.GetEncoding("iso-8859-15");
            information = "";
            StringBuilder sb          = new StringBuilder();
            uint          bootSectors = JFS_BOOT_BLOCKS_SIZE / imagePlugin.Info.SectorSize;
            byte[]        sector      = imagePlugin.ReadSector(partition.Start + bootSectors);
            if(sector.Length < 512) return;

            JfsSuperBlock jfsSb = Marshal.ByteArrayToStructureLittleEndian<JfsSuperBlock>(sector);

            sb.AppendLine("JFS filesystem");
            sb.AppendFormat("Version {0}", jfsSb.s_version).AppendLine();
            sb.AppendFormat("{0} blocks of {1} bytes", jfsSb.s_size, jfsSb.s_bsize).AppendLine();
            sb.AppendFormat("{0} blocks per allocation group", jfsSb.s_agsize).AppendLine();

            if(jfsSb.s_flags.HasFlag(JfsFlags.Unicode)) sb.AppendLine("Volume uses Unicode for directory entries");
            if(jfsSb.s_flags.HasFlag(JfsFlags.RemountRO)) sb.AppendLine("Volume remounts read-only on error");
            if(jfsSb.s_flags.HasFlag(JfsFlags.Continue)) sb.AppendLine("Volume continues on error");
            if(jfsSb.s_flags.HasFlag(JfsFlags.Panic)) sb.AppendLine("Volume panics on error");
            if(jfsSb.s_flags.HasFlag(JfsFlags.UserQuota)) sb.AppendLine("Volume has user quotas enabled");
            if(jfsSb.s_flags.HasFlag(JfsFlags.GroupQuota)) sb.AppendLine("Volume has group quotas enabled");
            if(jfsSb.s_flags.HasFlag(JfsFlags.NoJournal)) sb.AppendLine("Volume is not using any journal");
            if(jfsSb.s_flags.HasFlag(JfsFlags.Discard))
                sb.AppendLine("Volume sends TRIM/UNMAP commands to underlying device");
            if(jfsSb.s_flags.HasFlag(JfsFlags.GroupCommit)) sb.AppendLine("Volume commits in groups of 1");
            if(jfsSb.s_flags.HasFlag(JfsFlags.LazyCommit)) sb.AppendLine("Volume commits lazy");
            if(jfsSb.s_flags.HasFlag(JfsFlags.Temporary)) sb.AppendLine("Volume does not commit to log");
            if(jfsSb.s_flags.HasFlag(JfsFlags.InlineLog)) sb.AppendLine("Volume has log withing itself");
            if(jfsSb.s_flags.HasFlag(JfsFlags.InlineMoving))
                sb.AppendLine("Volume has log withing itself and is moving it out");
            if(jfsSb.s_flags.HasFlag(JfsFlags.BadSAIT)) sb.AppendLine("Volume has bad current secondary ait");
            if(jfsSb.s_flags.HasFlag(JfsFlags.Sparse)) sb.AppendLine("Volume supports sparse files");
            if(jfsSb.s_flags.HasFlag(JfsFlags.DASDEnabled)) sb.AppendLine("Volume has DASD limits enabled");
            if(jfsSb.s_flags.HasFlag(JfsFlags.DASDPrime)) sb.AppendLine("Volume primes DASD on boot");
            if(jfsSb.s_flags.HasFlag(JfsFlags.SwapBytes)) sb.AppendLine("Volume is in a big-endian system");
            if(jfsSb.s_flags.HasFlag(JfsFlags.DirIndex)) sb.AppendLine("Volume has presistent indexes");
            if(jfsSb.s_flags.HasFlag(JfsFlags.Linux)) sb.AppendLine("Volume supports Linux");
            if(jfsSb.s_flags.HasFlag(JfsFlags.DFS)) sb.AppendLine("Volume supports DCE DFS LFS");
            if(jfsSb.s_flags.HasFlag(JfsFlags.OS2)) sb.AppendLine("Volume supports OS/2, and is case insensitive");
            if(jfsSb.s_flags.HasFlag(JfsFlags.AIX)) sb.AppendLine("Volume supports AIX");
            if(jfsSb.s_state != 0) sb.AppendLine("Volume is dirty");
            sb.AppendFormat("Volume was last updated on {0}",
                            DateHandlers.UnixUnsignedToDateTime(jfsSb.s_time.tv_sec, jfsSb.s_time.tv_nsec))
              .AppendLine();
            if(jfsSb.s_version == 1)
                sb.AppendFormat("Volume name: {0}", StringHandlers.CToString(jfsSb.s_fpack, Encoding)).AppendLine();
            else sb.AppendFormat("Volume name: {0}", StringHandlers.CToString(jfsSb.s_label, Encoding)).AppendLine();
            sb.AppendFormat("Volume UUID: {0}", jfsSb.s_uuid).AppendLine();

            XmlFsType = new FileSystemType
            {
                Type        = "JFS filesystem",
                Clusters    = jfsSb.s_size,
                ClusterSize = jfsSb.s_bsize,
                Bootable    = true,
                VolumeName =
                    StringHandlers.CToString(jfsSb.s_version == 1 ? jfsSb.s_fpack : jfsSb.s_label, Encoding),
                VolumeSerial = $"{jfsSb.s_uuid}",
                ModificationDate =
                    DateHandlers.UnixUnsignedToDateTime(jfsSb.s_time.tv_sec, jfsSb.s_time.tv_nsec),
                ModificationDateSpecified = true
            };
            if(jfsSb.s_state != 0) XmlFsType.Dirty = true;

            information = sb.ToString();
        }

        [Flags]
        enum JfsFlags : uint
        {
            Unicode      = 0x00000001,
            RemountRO    = 0x00000002,
            Continue     = 0x00000004,
            Panic        = 0x00000008,
            UserQuota    = 0x00000010,
            GroupQuota   = 0x00000020,
            NoJournal    = 0x00000040,
            Discard      = 0x00000080,
            GroupCommit  = 0x00000100,
            LazyCommit   = 0x00000200,
            Temporary    = 0x00000400,
            InlineLog    = 0x00000800,
            InlineMoving = 0x00001000,
            BadSAIT      = 0x00010000,
            Sparse       = 0x00020000,
            DASDEnabled  = 0x00040000,
            DASDPrime    = 0x00080000,
            SwapBytes    = 0x00100000,
            DirIndex     = 0x00200000,
            Linux        = 0x10000000,
            DFS          = 0x20000000,
            OS2          = 0x40000000,
            AIX          = 0x80000000
        }

        [Flags]
        enum JfsState : uint
        {
            Clean    = 0,
            Mounted  = 1,
            Dirty    = 2,
            Logredo  = 4,
            Extendfs = 8
        }

        [StructLayout(LayoutKind.Sequential, Pack = 1)]
        struct JfsExtent
        {
            /// <summary>
            ///     Leftmost 24 bits are extent length, rest 8 bits are most significant for <see cref="addr2" />
            /// </summary>
            public readonly uint len_addr;
            public readonly uint addr2;
        }

        [StructLayout(LayoutKind.Sequential, Pack = 1)]
        struct JfsTimeStruct
        {
            public readonly uint tv_sec;
            public readonly uint tv_nsec;
        }

        [StructLayout(LayoutKind.Sequential, Pack = 1)]
        struct JfsSuperBlock
        {
            public readonly uint          s_magic;
            public readonly uint          s_version;
            public readonly ulong         s_size;
            public readonly uint          s_bsize;
            public readonly ushort        s_l2bsize;
            public readonly ushort        s_l2bfactor;
            public readonly uint          s_pbsize;
            public readonly ushort        s_l1pbsize;
            public readonly ushort        pad;
            public readonly uint          s_agsize;
            public readonly JfsFlags      s_flags;
            public readonly JfsState      s_state;
            public readonly uint          s_compress;
            public readonly JfsExtent     s_ait2;
            public readonly JfsExtent     s_aim2;
            public readonly uint          s_logdev;
            public readonly uint          s_logserial;
            public readonly JfsExtent     s_logpxd;
            public readonly JfsExtent     s_fsckpxd;
            public readonly JfsTimeStruct s_time;
            public readonly uint          s_fsckloglen;
            public readonly sbyte         s_fscklog;
            [MarshalAs(UnmanagedType.ByValArray, SizeConst = 11)]
            public readonly byte[] s_fpack;
            public readonly ulong     s_xsize;
            public readonly JfsExtent s_xfsckpxd;
            public readonly JfsExtent s_xlogpxd;
            public readonly Guid      s_uuid;
            [MarshalAs(UnmanagedType.ByValArray, SizeConst = 16)]
            public readonly byte[] s_label;
            public readonly Guid s_loguuid;
        }
    }
}