NTFS on non-Windows systems.

Much of your NTFS implementation relies on RawSecurityDescriptor and SecurityIdentifier.

This is not supported on some non-windows CLR environments (.NET Core App 2), it infact throws an exception:

public RawSecurityDescriptor(byte[] binaryForm, int offset)
{
    throw new PlatformNotSupportedException(SR.PlatformNotSupported_AccessControl);
}

This includes when you perform Null checks.

public sealed class SecurityIdentifier : IdentityReference, IComparable<SecurityIdentifier>
{
...
    public static bool operator ==(SecurityIdentifier left, SecurityIdentifier right)
    {
      throw new PlatformNotSupportedException(SR.PlatformNotSupported_Principal);
    }
...
}

I have some code written to allow you to determine if this is available at runtime:

private static bool? _HasRawSecurityDescriptors;

public static bool HasRawSecurityDescriptors
{
	get 
	{
		if (_HasRawSecurityDescriptors == null)
		{
			try
			{
				// The `if` will throw if we do not support this functionality 
				// at runtime.
				SecurityIdentifier willThrowIfNoPolicyFramework = null;
				// ReSharper disable once ConditionIsAlwaysTrueOrFalse
				if (willThrowIfNoPolicyFramework == null) {}
				_HasRawSecurityDescriptors = true;
			}
			catch (PlatformNotSupportedException ex)
			{
				_HasRawSecurityDescriptors = false;
			}
		}

		return _HasRawSecurityDescriptors ?? false;
	}
}

It would be nice to be able to create NTFS volumes on other systems without relying on native support that doesn’t exist outside of the Windows CLR.

[grmartin]

Whats fascinating is this code partially works on Mono… but .NET Core explicitly throws.

Mono

Gaius:DiscUtils grmartin$ csharp -e "System.Security.Principal.WindowsIdentity.GetCurrent().Token"
501

.NET Core

Unhandled Exception: System.TypeInitializationException: The type initializer for '<StartupCode$MacTestApp>.$Program' threw an exception. ---> System.PlatformNotSupportedException: Windows Principal functionality is not supported on this platform

[vddCore]

I did it some time ago, then forgot about it. Feel free to backport whatever, it’s all taken from Mono project anyway.

https://github.com/Ciastex/DiscUtils/commit/cf64cfc4a05763e1ebe655da6e05b7a7993ef246