// (c) 2006 Richard Grimes
// www.grimes.demon.co.uk

using System;
using System.IO;
using System.Text;
using System.Security.AccessControl;

class App
{
   const string file = "test.txt";
   public static void Main(string[] args)
   {
      if (args.Length == 0)
      {
         if (File.Exists(file))
            File.Delete(file);
         DirectoryInfo dir = new DirectoryInfo(".");
         DirectorySecurity ds = dir.GetAccessControl(AccessControlSections.Access);
         
         FileSecurity fs = new FileSecurity();
         fs.SetSecurityDescriptorBinaryForm(ds.GetSecurityDescriptorBinaryForm());

         fs.AddAccessRule(new FileSystemAccessRule(
            @"BUILTIN\Users",
            FileSystemRights.ReadData | FileSystemRights.ReadExtendedAttributes,
            AccessControlType.Allow));

         using (FileStream fWrite = new FileStream(
            file, FileMode.Create,
            FileSystemRights.WriteData,
            FileShare.None, 256, FileOptions.None, fs))
         {

            byte[] buf = Encoding.ASCII.GetBytes("this is data");
            fWrite.Write(buf, 0, buf.Length);
         }
      }
      else
      {
         using (FileStream fRead = new FileStream(file, FileMode.Open, FileAccess.Read, FileShare.None))
         {
            StreamReader sr = new StreamReader(fRead);
            Console.WriteLine(sr.ReadToEnd());
         }
      }
   }
}