How to manage folders permissions on Mac OS with ACL in .NET Core 3.1.0

Question

I have the following code in C#:

if (!Directory.Exists(inputFolder))
        {
            return true;
        }
        else
        {
            var me = new DirectoryInfo(inputFolder);

            AuthorizationRuleCollection rules = null;
            WindowsIdentity identity = null;
            try
            {
                rules = me.GetAccessControl().GetAccessRules(true, true, typeof(SecurityIdentifier));
                identity = WindowsIdentity.GetCurrent();
            }
            catch (UnauthorizedAccessException uae)
            {
                return false;
            }

            string userSID = identity.User.Value;

            foreach (FileSystemAccessRule rule in rules)
            {
                if ((rule.FileSystemRights.HasFlag(FileSystemRights.Read) ||
                    rule.FileSystemRights.HasFlag(FileSystemRights.ReadAttributes) ||
                    rule.FileSystemRights.HasFlag(FileSystemRights.ReadData) ||
                    rule.FileSystemRights.HasFlag(FileSystemRights.ReadAndExecute)) && rule.AccessControlType == AccessControlType.Deny)
                {
                    return false;
                }
            }

            return true;
        }

And it works correctly in Windows, however, when I try to run this on mac OS X (Visual Studio for Mac) it throws an exception when trying to get the information from the method "GetAccessRules" or even the "GetAccessControl" saying:

"Access Control List (ACL) APIs are part of resource management on Windows and are not supported on this platform."

So here is my question:

Is there an alternative to do this in .net core? Or how should i manage these kind of permissions in .net core but in mac OS X?

Answer 1

I am assuming you are using System.IO.FileSystem.AccessControl to make GetAccessControl() work on .NET Core ? Unfortunately these APIs are closely tied to Windows low level APIs and won't work on Unix/Linux systems.

However, there is an alternative. You could give Mono.Posix.NETStandard a try. Here is the Nuget link.

You can call UnixDirectoryInfo() and get or set FileAccessPermissions that way.

Answer 2

Updated

I found the solution and it was the same provided by Ruv in the answer above.

So, installing the Nuget Package Mono.Posix.NETStandard works. Just get the information of the directory/file: var unixDirInfo = new Mono.Unix.UnixDirectoryInfo('path');

Then you can check the permissions like this:

    unixDirInfo.canAccess(AccessModes.F_OK) // is a file or directory
    unixDirInfo.canAccess(AccessModes.R_OK) // accessible for reading
    unixDirInfo.canAccess(AccessModes.W_OK) // accessible for writing
    unixDirInfo.canAccess(AccessModes.X_OK) // accessible for executing

or from the FileAccessPermissions:

    FileAccessPermissions permissions = unixDirInfo.FileAccessPermissions;
    permissions.HasFlag(FileAccessPermissions.UserRead);
    permissions.HasFlag(FileAccessPermissions.UserWrite);
    permissions.HasFlag(FileAccessPermissions.UserExecute);
    permissions.HasFlag(FileAccessPermissions.UserExecute .UserReadWriteExecute);

You can check the FileAccessPermission enum for more information.