/// <summary>
/// Helper method to create a junction.
/// </summary>
/// <param name="path">The path of the junction to create.</param>
/// <param name="target">The target for the junction.</param>
public virtual void CreateJunction(string path, string target)
{
path = Path.GetFullPath(path);
target = Path.GetFullPath(target);
Win32FindData data;
using (var handle = NativeMethods.FindFirstFile(path, out data))
{
if (!handle.IsInvalid)
{
throw new InvalidOperationException("A file or folder already exists with the same name as the junction.");
}
}
Directory.CreateDirectory(path);
var encoding = Encoding.Unicode;
var nullChar = new byte[] { 0, 0 };
var printName = ParseDosDevicePath(target);
var printNameBytes = encoding.GetBytes(printName);
var printNameLength = printNameBytes.Length;
var substituteName = FormatDosDevicePath(printName, false);
var substituteNameBytes = encoding.GetBytes(substituteName);
var substituteNameLength = substituteNameBytes.Length;
var junction = new JunctionData
{
SubstituteNameOffset = 0,
SubstituteNameLength = checked ((ushort)substituteNameLength),
PrintNameOffset = checked ((ushort)(substituteNameLength + nullChar.Length)),
PrintNameLength = checked ((ushort)printNameLength)
};
var junctionLength = Marshal.SizeOf(junction) + nullChar.Length * 2;
var reparseLength = junctionLength + junction.SubstituteNameLength + junction.PrintNameLength;
var reparse = new ReparseHeader
{
ReparseTag = Win32Constants.IO_REPARSE_TAG_MOUNT_POINT,
ReparseDataLength = checked ((ushort)(reparseLength)),
Reserved = 0,
};
var bufferLength = Marshal.SizeOf(reparse) + reparse.ReparseDataLength;
using (var hReparsePoint = OpenReparsePoint(path, AccessRights.GenericWrite))
using (var buffer = SafeLocalAllocHandle.Allocate(bufferLength))
{
var offset = buffer.Write(0, reparse);
offset += buffer.Write(offset, junction);
offset += buffer.Write(offset, substituteNameBytes, 0, substituteNameBytes.Length);
offset += buffer.Write(offset, nullChar, 0, nullChar.Length);
offset += buffer.Write(offset, printNameBytes, 0, printNameBytes.Length);
offset += buffer.Write(offset, nullChar, 0, nullChar.Length);
Debug.Assert(offset == bufferLength);
int bytesReturned;
var b = NativeMethods.DeviceIoControl(
hReparsePoint,
Win32Constants.FSCTL_SET_REPARSE_POINT,
buffer,
bufferLength,
SafeLocalAllocHandle.InvalidHandle,
0,
out bytesReturned,
IntPtr.Zero);
if (!b)
{
throw new Win32Exception();
}
}
}
/// <summary>
/// Given a path, returns the information about a reparse point.
/// </summary>
/// <param name="path">The path to inspect.</param>
/// <returns>A <see cref="ReparseLink"/> that contains the information
/// about a reparse point.</returns>
public virtual ReparseLink GetLink(string path)
{
FileAttributes attributes;
try
{
attributes = File.GetAttributes(path);
}
catch (DirectoryNotFoundException)
{
return(new ReparseLink());
}
catch (FileNotFoundException)
{
return(new ReparseLink());
}
var link = new ReparseLink
{
Attributes = attributes
};
if (!attributes.HasFlag(FileAttributes.ReparsePoint))
{
link.Type = attributes.HasFlag(FileAttributes.Directory)
? LinkType.Unknown
: LinkType.HardLink;
return(link);
}
var encoding = Encoding.Unicode;
var reparseHeaderSize = Marshal.SizeOf(typeof(ReparseHeader));
var bufferLength = reparseHeaderSize + 2048;
using (var hReparsePoint = OpenReparsePoint(path, AccessRights.GenericRead))
{
int error;
do
{
using (var buffer = SafeLocalAllocHandle.Allocate(bufferLength))
{
int bytesReturned;
var b = NativeMethods.DeviceIoControl(
hReparsePoint,
Win32Constants.FSCTL_GET_REPARSE_POINT,
SafeLocalAllocHandle.InvalidHandle,
0,
buffer,
bufferLength,
out bytesReturned,
IntPtr.Zero);
error = Marshal.GetLastWin32Error();
if (b)
{
var reparseHeader = buffer.Read <ReparseHeader>(0);
IReparseData data;
switch (reparseHeader.ReparseTag)
{
case Win32Constants.IO_REPARSE_TAG_MOUNT_POINT:
data = buffer.Read <JunctionData>(reparseHeaderSize);
link.Type = LinkType.Junction;
break;
case Win32Constants.IO_REPARSE_TAG_SYMLINK:
data = buffer.Read <SymbolicData>(reparseHeaderSize);
link.Type = LinkType.Symbolic;
break;
default:
throw new InvalidOperationException(String.Format(
"An unknown reparse tag {0:X} was encountered.",
reparseHeader.ReparseTag));
}
var offset = Marshal.SizeOf(data) + reparseHeaderSize;
var target = buffer.ReadString(offset + data.SubstituteNameOffset, data.SubstituteNameLength, encoding);
link.Target = ParseDosDevicePath(target);
return(link);
}
if (error == Win32Constants.ERROR_INSUFFICIENT_BUFFER)
{
var reparseHeader = buffer.Read <ReparseHeader>(0);
bufferLength = reparseHeader.ReparseDataLength;
}
else
{
throw new Win32Exception(error);
}
}
}while (error == Win32Constants.ERROR_INSUFFICIENT_BUFFER);
}
return(link);
}
