// /***************************************************************************
// The Disc Image Chef
// ----------------------------------------------------------------------------
//
// Filename       : BSD.cs
// Author(s)      : Natalia Portillo <claunia@claunia.com>
//
// Component      : Partitioning scheme plugins.
//
// --[ Description ] ----------------------------------------------------------
//
//     Manages BSD disklabels.
//
// --[ 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 © 2011-2018 Natalia Portillo
// ****************************************************************************/

using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.InteropServices;
using DiscImageChef.CommonTypes;
using DiscImageChef.Console;
using DiscImageChef.DiscImages;

namespace DiscImageChef.Partitions
{
    public class BSD : PartitionPlugin
    {
        const uint DISKMAGIC = 0x82564557;
        const uint DISKCIGAM = 0x57455682;
        /// <summary>Known sector locations for BSD disklabel</summary>
        readonly ulong[] labelLocations = {0, 1, 2, 9};
        /// <summary>Known byte offsets for BSD disklabel</summary>
        readonly uint[] labelOffsets = {0, 9, 64, 128, 516};
        /// <summary>Maximum size of a disklabel with 22 partitions</summary>
        const uint maxLabelSize = 500;

        public BSD()
        {
            Name = "BSD disklabel";
            PluginUuid = new Guid("246A6D93-4F1A-1F8A-344D-50187A5513A9");
        }

        public override bool GetInformation(ImagePlugin imagePlugin, out List<Partition> partitions, ulong sectorOffset)
        {
            partitions = new List<Partition>();
            uint run = (maxLabelSize + labelOffsets.Last()) / imagePlugin.GetSectorSize();
            if((maxLabelSize + labelOffsets.Last()) % imagePlugin.GetSectorSize() > 0) run++;

            byte[] sector;
            DiskLabel dl = new DiskLabel();
            bool found = false;

            foreach(ulong location in labelLocations)
            {
                if(location + run + sectorOffset >= imagePlugin.GetSectors()) return false;

                byte[] tmp = imagePlugin.ReadSectors(location + sectorOffset, run);
                foreach(uint offset in labelOffsets)
                {
                    sector = new byte[maxLabelSize];
                    Array.Copy(tmp, offset, sector, 0, maxLabelSize);
                    dl = GetDiskLabel(sector);
                    DicConsole.DebugWriteLine("BSD plugin",
                                              "dl.magic on sector {0} at offset {1} = 0x{2:X8} (expected 0x{3:X8})",
                                              location + sectorOffset, offset, dl.d_magic, DISKMAGIC);
                    if((dl.d_magic != DISKMAGIC || dl.d_magic2 != DISKMAGIC) &&
                       (dl.d_magic != DISKCIGAM || dl.d_magic2 != DISKCIGAM)) continue;

                    found = true;
                    break;
                }

                if(found) break;
            }

            if(!found) return false;

            if(dl.d_magic == DISKCIGAM && dl.d_magic2 == DISKCIGAM) dl = SwapDiskLabel(dl);

            DicConsole.DebugWriteLine("BSD plugin", "dl.d_type = {0}", dl.d_type);
            DicConsole.DebugWriteLine("BSD plugin", "dl.d_subtype = {0}", dl.d_subtype);
            DicConsole.DebugWriteLine("BSD plugin", "dl.d_typename = {0}", StringHandlers.CToString(dl.d_typename));
            DicConsole.DebugWriteLine("BSD plugin", "dl.d_packname = {0}", StringHandlers.CToString(dl.d_packname));
            DicConsole.DebugWriteLine("BSD plugin", "dl.d_secsize = {0}", dl.d_secsize);
            DicConsole.DebugWriteLine("BSD plugin", "dl.d_nsectors = {0}", dl.d_nsectors);
            DicConsole.DebugWriteLine("BSD plugin", "dl.d_ntracks = {0}", dl.d_ntracks);
            DicConsole.DebugWriteLine("BSD plugin", "dl.d_ncylinders = {0}", dl.d_ncylinders);
            DicConsole.DebugWriteLine("BSD plugin", "dl.d_secpercyl = {0}", dl.d_secpercyl);
            DicConsole.DebugWriteLine("BSD plugin", "dl.d_secperunit = {0}", dl.d_secperunit);
            DicConsole.DebugWriteLine("BSD plugin", "dl.d_sparespertrack = {0}", dl.d_sparespertrack);
            DicConsole.DebugWriteLine("BSD plugin", "dl.d_sparespercyl = {0}", dl.d_sparespercyl);
            DicConsole.DebugWriteLine("BSD plugin", "dl.d_acylinders = {0}", dl.d_acylinders);
            DicConsole.DebugWriteLine("BSD plugin", "dl.d_rpm = {0}", dl.d_rpm);
            DicConsole.DebugWriteLine("BSD plugin", "dl.d_interleave = {0}", dl.d_interleave);
            DicConsole.DebugWriteLine("BSD plugin", "dl.d_trackskew = {0}", dl.d_trackskew);
            DicConsole.DebugWriteLine("BSD plugin", "dl.d_cylskeew = {0}", dl.d_cylskeew);
            DicConsole.DebugWriteLine("BSD plugin", "dl.d_headswitch = {0}", dl.d_headswitch);
            DicConsole.DebugWriteLine("BSD plugin", "dl.d_trkseek = {0}", dl.d_trkseek);
            DicConsole.DebugWriteLine("BSD plugin", "dl.d_flags = {0}", dl.d_flags);
            DicConsole.DebugWriteLine("BSD plugin", "dl.d_drivedata[0] = {0}", dl.d_drivedata[0]);
            DicConsole.DebugWriteLine("BSD plugin", "dl.d_drivedata[1] = {0}", dl.d_drivedata[1]);
            DicConsole.DebugWriteLine("BSD plugin", "dl.d_drivedata[2] = {0}", dl.d_drivedata[2]);
            DicConsole.DebugWriteLine("BSD plugin", "dl.d_drivedata[3] = {0}", dl.d_drivedata[3]);
            DicConsole.DebugWriteLine("BSD plugin", "dl.d_drivedata[4] = {0}", dl.d_drivedata[4]);
            DicConsole.DebugWriteLine("BSD plugin", "dl.d_spare[0] = {0}", dl.d_spare[0]);
            DicConsole.DebugWriteLine("BSD plugin", "dl.d_spare[1] = {0}", dl.d_spare[1]);
            DicConsole.DebugWriteLine("BSD plugin", "dl.d_spare[2] = {0}", dl.d_spare[2]);
            DicConsole.DebugWriteLine("BSD plugin", "dl.d_spare[3] = {0}", dl.d_spare[3]);
            DicConsole.DebugWriteLine("BSD plugin", "dl.d_spare[4] = {0}", dl.d_spare[4]);
            DicConsole.DebugWriteLine("BSD plugin", "dl.d_magic2 = 0x{0:X8}", dl.d_magic2);
            DicConsole.DebugWriteLine("BSD plugin", "dl.d_checksum = 0x{0:X8}", dl.d_checksum);
            DicConsole.DebugWriteLine("BSD plugin", "dl.d_npartitions = {0}", dl.d_npartitions);
            DicConsole.DebugWriteLine("BSD plugin", "dl.d_bbsize = {0}", dl.d_bbsize);
            DicConsole.DebugWriteLine("BSD plugin", "dl.d_sbsize = {0}", dl.d_sbsize);

            ulong counter = 0;
            bool addSectorOffset = false;

            for(int i = 0; i < dl.d_npartitions && i < 22; i++)
            {
                DicConsole.DebugWriteLine("BSD plugin", "dl.d_partitions[i].p_offset = {0}",
                                          dl.d_partitions[i].p_offset);
                DicConsole.DebugWriteLine("BSD plugin", "dl.d_partitions[i].p_size = {0}", dl.d_partitions[i].p_size);
                DicConsole.DebugWriteLine("BSD plugin", "dl.d_partitions[i].p_fstype = {0} ({1})",
                                          dl.d_partitions[i].p_fstype, fsTypeToString(dl.d_partitions[i].p_fstype));
                Partition part = new Partition
                {
                    Start = dl.d_partitions[i].p_offset * dl.d_secsize / imagePlugin.GetSectorSize(),
                    Offset = dl.d_partitions[i].p_offset * dl.d_secsize,
                    Length = dl.d_partitions[i].p_size * dl.d_secsize / imagePlugin.GetSectorSize(),
                    Size = dl.d_partitions[i].p_size * dl.d_secsize,
                    Type = fsTypeToString(dl.d_partitions[i].p_fstype),
                    Sequence = counter,
                    Scheme = Name
                };
                if(dl.d_partitions[i].p_fstype == fsType.Unused) continue;
                // Crude and dirty way to know if the disklabel is relative to its parent partition...
                if(dl.d_partitions[i].p_offset < sectorOffset && !addSectorOffset) addSectorOffset = true;

                if(addSectorOffset)
                {
                    part.Start += sectorOffset;
                    part.Offset += sectorOffset * imagePlugin.GetSectorSize();
                }
                DicConsole.DebugWriteLine("BSD plugin", "part.start = {0}", part.Start);
                DicConsole.DebugWriteLine("BSD plugin", "Adding it...");
                partitions.Add(part);
                counter++;
            }

            return partitions.Count > 0;
        }

        /// <summary>Drive type</summary>
        enum dType : ushort
        {
            /// <summary>SMD, XSMD</summary>
            SMD = 1,
            /// <summary>MSCP</summary>
            MSCP = 2,
            /// <summary>Other DEC (rk, rl)</summary>
            DEC = 3,
            /// <summary>SCSI</summary>
            SCSI = 4,
            /// <summary>ESDI</summary>
            ESDI = 5,
            /// <summary>ST506 et al</summary>
            ST506 = 6,
            /// <summary>CS/80 on HP-IB</summary>
            HPIB = 7,
            /// <summary>HP Fiber-link</summary>
            HPFL = 8,
            /// <summary>Floppy</summary>
            FLOPPY = 10,
            /// <summary>Concatenated disk</summary>
            CCD = 11,
            /// <summary>uvnode pseudo-disk</summary>
            VND = 12,
            /// <summary>DiskOnChip</summary>
            DOC2K = 13,
            /// <summary>ATAPI</summary>
            ATAPI = 13,
            /// <summary>CMU RAIDframe</summary>
            RAID = 14,
            /// <summary>Logical disk</summary>
            LD = 15,
            /// <summary>IBM JFS 2</summary>
            JFS2 = 16,
            /// <summary>Cryptographic pseudo-disk</summary>
            CGD = 17,
            /// <summary>Vinum volume</summary>
            VINUM = 18,
            /// <summary>Flash memory devices</summary>
            FLASH = 19,
            /// <summary>Device-mapper pseudo-disk devices</summary>
            DM = 20,
            /// <summary>Rump virtual disk</summary>
            RUMPD = 21,
            /// <summary>Memory disk</summary>
            MD = 22
        }

        /// <summary>Filesystem type</summary>
        internal enum fsType : byte
        {
            /// <summary>Unused entry</summary>
            Unused = 0,
            /// <summary>Swap partition</summary>
            Swap = 1,
            /// <summary>UNIX 6th Edition</summary>
            V6 = 2,
            /// <summary>UNIX 7th Edition</summary>
            V7 = 3,
            /// <summary>UNIX System V</summary>
            SystemV = 4,
            /// <summary>UNIX 7th Edition with 1K blocks</summary>
            V7_1K = 5,
            /// <summary>UNIX 8th Edition with 4K blocks</summary>
            V8 = 6,
            /// <summary>4.2BSD Fast File System</summary>
            BSDFFS = 7,
            /// <summary>MS-DOS filesystem</summary>
            MSDOS = 8,
            /// <summary>4.4LFS</summary>
            BSDLFS = 9,
            /// <summary>In use, unknown or unsupported</summary>
            Other = 10,
            /// <summary>HPFS</summary>
            HPFS = 11,
            /// <summary>ISO9660</summary>
            ISO9660 = 12,
            /// <summary>Boot partition</summary>
            Boot = 13,
            /// <summary>Amiga FFS</summary>
            AFFS = 14,
            /// <summary>Apple HFS</summary>
            HFS = 15,
            /// <summary>Acorn ADFS</summary>
            FileCore = 16,
            /// <summary>Digital Advanced File System</summary>
            ADVfs = 16,
            /// <summary>Digital LSM Public Region</summary>
            LSMpublic = 17,
            /// <summary>Linux ext2</summary>
            ext2 = 17,
            /// <summary>Digital LSM Private Region</summary>
            LSMprivate = 18,
            /// <summary>NTFS</summary>
            NTFS = 18,
            /// <summary>Digital LSM Simple Disk</summary>
            LSMsimple = 19,
            /// <summary>RAIDframe component</summary>
            RAID = 19,
            /// <summary>Concatenated disk component</summary>
            CCD = 20,
            /// <summary>IBM JFS2</summary>
            JFS2 = 21,
            /// <summary>Apple UFS</summary>
            AppleUFS = 22,
            /// <summary>Hammer filesystem</summary>
            HAMMER = 22,
            /// <summary>Hammer2 filesystem</summary>
            HAMMER2 = 23,
            /// <summary>UDF</summary>
            UDF = 24,
            /// <summary>System V Boot filesystem</summary>
            SysVBoot = 25,
            /// <summary>EFS</summary>
            EFS = 26,
            /// <summary>ZFS</summary>
            ZFS = 27,
            /// <summary>NiLFS</summary>
            NILFS = 27,
            /// <summary>Cryptographic disk</summary>
            CGD = 28,
            /// <summary>MINIX v3</summary>
            MINIX = 29,
            /// <summary>FreeBSD nandfs</summary>
            NANDFS = 30
        }

        /// <summary>
        /// Drive flags
        /// </summary>
        [Flags]
        enum dFlags : uint
        {
            /// <summary>Removable media</summary>
            Removable = 0x01,
            /// <summary>Drive supports ECC</summary>
            ECC = 0x02,
            /// <summary>Drive supports bad sector forwarding</summary>
            BadSectorForward = 0x04,
            /// <summary>Disk emulator</summary>
            RAMDisk = 0x08,
            /// <summary>Can do back to back transfer</summary>
            Chain = 0x10,
            /// <summary>Dynamic geometry device</summary>
            DynamicGeometry = 0x20
        }

        [StructLayout(LayoutKind.Sequential, Pack = 1)]
        struct DiskLabel
        {
            /// <summary><see cref="DISKMAGIC"/></summary>
            public uint d_magic;
            /// <summary><see cref="dType"/></summary>
            public dType d_type;
            /// <summary>Disk subtype</summary>
            public ushort d_subtype;
            /// <summary>Type name</summary>
            [MarshalAs(UnmanagedType.ByValArray, SizeConst = 16)] public byte[] d_typename;
            /// <summary>Pack identifier</summary>
            [MarshalAs(UnmanagedType.ByValArray, SizeConst = 16)] public byte[] d_packname;
            /// <summary>Bytes per sector</summary>
            public uint d_secsize;
            /// <summary>Sectors per track</summary>
            public uint d_nsectors;
            /// <summary>Tracks per cylinder</summary>
            public uint d_ntracks;
            /// <summary>Cylinders per unit</summary>
            public uint d_ncylinders;
            /// <summary>Sectors per cylinder</summary>
            public uint d_secpercyl;
            /// <summary>Sectors per unit</summary>
            public uint d_secperunit;
            /// <summary>Spare sectors per track</summary>
            public ushort d_sparespertrack;
            /// <summary>Spare sectors per cylinder</summary>
            public ushort d_sparespercyl;
            /// <summary>Alternate cylinders</summary>
            public uint d_acylinders;
            /// <summary>Rotational speed</summary>
            public ushort d_rpm;
            /// <summary>Hardware sector interleave</summary>
            public ushort d_interleave;
            /// <summary>Sector 0 skew per track</summary>
            public ushort d_trackskew;
            /// <summary>Sector 0 sker per cylinder</summary>
            public ushort d_cylskeew;
            /// <summary>Head switch time in microseconds</summary>
            public uint d_headswitch;
            /// <summary>Track to track seek in microseconds</summary>
            public uint d_trkseek;
            /// <summary><see cref="dFlags"/></summary>
            public dFlags d_flags;
            /// <summary>Drive-specific information</summary>
            [MarshalAs(UnmanagedType.ByValArray, SizeConst = 5)] public uint[] d_drivedata;
            /// <summary>Reserved</summary>
            [MarshalAs(UnmanagedType.ByValArray, SizeConst = 5)]
            /// <summary></summary>
            public uint[] d_spare;
            /// <summary><see cref="DISKMAGIC"/> again</summary>
            public uint d_magic2;
            /// <summary>XOR of data</summary>
            public ushort d_checksum;
            /// <summary>How many partitions</summary>
            public ushort d_npartitions;
            /// <summary>Size of boot area in bytes</summary>
            public uint d_bbsize;
            /// <summary>Maximum size of superblock in bytes</summary>
            public uint d_sbsize;
            /// <summary>Partitions</summary>
            [MarshalAs(UnmanagedType.ByValArray, SizeConst = 22)] public BSDPartition[] d_partitions;
        }

        [StructLayout(LayoutKind.Sequential, Pack = 1)]
        struct BSDPartition
        {
            /// <summary>Sectors in partition</summary>
            public uint p_size;
            /// <summary>Starting sector</summary>
            public uint p_offset;
            /// <summary>Fragment size</summary>
            public uint p_fsize;
            /// <summary>Filesystem type, <see cref="fsType"/></summary>
            public fsType p_fstype;
            /// <summary>Fragment size</summary>
            public byte p_frag;
            /// <summary>Cylinder per group</summary>
            public ushort p_cpg;
        }

        internal static string fsTypeToString(fsType typ)
        {
            switch(typ)
            {
                case fsType.Unused: return "Unused entry";
                case fsType.Swap: return "Swap partition";
                case fsType.V6: return "UNIX 6th Edition";
                case fsType.V7: return "UNIX 7th Edition";
                case fsType.SystemV: return "UNIX System V";
                case fsType.V7_1K: return "UNIX 7th Edition with 1K blocks";
                case fsType.V8: return "UNIX 8th Edition with 4K blocks";
                case fsType.BSDFFS: return "4.2BSD Fast File System";
                case fsType.BSDLFS: return "4.4LFS";
                case fsType.HPFS: return "HPFS";
                case fsType.ISO9660: return "ISO9660";
                case fsType.Boot:
                case fsType.SysVBoot: return "Boot";
                case fsType.AFFS: return "Amiga FFS";
                case fsType.HFS: return "Apple HFS";
                case fsType.ADVfs: return "Digital Advanced File System";
                case fsType.LSMpublic: return "Digital LSM Public Region";
                case fsType.LSMprivate: return "Digital LSM Private Region";
                case fsType.LSMsimple: return "Digital LSM Simple Disk";
                case fsType.CCD: return "Concatenated disk";
                case fsType.JFS2: return "IBM JFS2";
                case fsType.HAMMER: return "Hammer";
                case fsType.HAMMER2: return "Hammer2";
                case fsType.UDF: return "UDF";
                case fsType.EFS: return "EFS";
                case fsType.ZFS: return "ZFS";
                case fsType.NANDFS: return "FreeBSD nandfs";
                case fsType.MSDOS: return "FAT";
                case fsType.Other: return "Other or unknown";
                default: return "Unknown";
            }
        }

        static DiskLabel GetDiskLabel(byte[] disklabel)
        {
            GCHandle handle = GCHandle.Alloc(disklabel, GCHandleType.Pinned);
            DiskLabel dl = (DiskLabel)Marshal.PtrToStructure(handle.AddrOfPinnedObject(), typeof(DiskLabel));
            handle.Free();
            return dl;
        }

        static DiskLabel SwapDiskLabel(DiskLabel disklabel)
        {
            DiskLabel dl = BigEndianMarshal.SwapStructureMembersEndian(disklabel);
            for(int i = 0; i < dl.d_drivedata.Length; i++) dl.d_drivedata[i] = Swapping.Swap(dl.d_drivedata[i]);
            for(int i = 0; i < dl.d_spare.Length; i++) dl.d_spare[i] = Swapping.Swap(dl.d_spare[i]);
            for(int i = 0; i < dl.d_partitions.Length; i++)
                dl.d_partitions[i] = BigEndianMarshal.SwapStructureMembersEndian(dl.d_partitions[i]);

            return dl;
        }
    }
}