/// <summary>
/// Creates a junction point from the specified directory to the specified target directory.
/// </summary>
/// <remarks>
/// Only works on NTFS.
/// </remarks>
/// <param name="junctionPoint">The junction point path</param>
/// <param name="targetDir">The target directory</param>
/// <param name="overwrite">If true overwrites an existing reparse point or empty directory</param>
/// <exception cref="IOException">Thrown when the junction point could not be created or when
/// an existing directory was found and <paramref name="overwrite" /> if false</exception>
public static void Create(string junctionPoint, string targetDir, bool overwrite)
{
targetDir = Path.GetFullPath(targetDir);
if (!Directory.Exists(targetDir))
{
throw new IOException("Target path does not exist or is not a directory.");
}
if (Directory.Exists(junctionPoint))
{
if (!overwrite)
{
throw new IOException("Directory already exists and overwrite parameter is false.");
}
}
else
{
Directory.CreateDirectory(junctionPoint);
}
using (var handle = OpenReparsePoint(junctionPoint, EFileAccess.GenericWrite)) {
var targetDirBytes = Encoding.Unicode.GetBytes(NonInterpretedPathPrefix + Path.GetFullPath(targetDir));
var reparseDataBuffer = new Reparse_Data_Buffer {
ReparseTag = IoReparseTagMountPoint,
ReparseDataLength = (ushort)(targetDirBytes.Length + 12),
SubstituteNameOffset = 0,
SubstituteNameLength = (ushort)targetDirBytes.Length,
PrintNameOffset = (ushort)(targetDirBytes.Length + 2),
PrintNameLength = 0,
PathBuffer = new byte[0x3ff0]
};
Array.Copy(targetDirBytes, reparseDataBuffer.PathBuffer, targetDirBytes.Length);
var inBufferSize = Marshal.SizeOf(reparseDataBuffer);
var inBuffer = Marshal.AllocHGlobal(inBufferSize);
try {
Marshal.StructureToPtr(reparseDataBuffer, inBuffer, false);
int bytesReturned;
var result = DeviceIoControl(handle.DangerousGetHandle(), FsctlSetReparsePoint,
inBuffer, targetDirBytes.Length + 20, IntPtr.Zero, 0, out bytesReturned, IntPtr.Zero);
if (!result)
{
ThrowLastWin32Error("Unable to create junction point.");
}
} finally {
Marshal.FreeHGlobal(inBuffer);
}
}
}
/// <summary>
/// Deletes a junction point at the specified source directory along with the directory itself.
/// Does nothing if the junction point does not exist.
/// </summary>
/// <remarks>
/// Only works on NTFS.
/// </remarks>
/// <param name="junctionPoint">The junction point path</param>
public static void Delete(string junctionPoint)
{
if (!Directory.Exists(junctionPoint))
{
if (File.Exists(junctionPoint))
{
throw new IOException("Path is not a junction point.");
}
return;
}
using (var handle = OpenReparsePoint(junctionPoint, EFileAccess.GenericWrite)) {
var reparseDataBuffer = new Reparse_Data_Buffer {
ReparseTag = IoReparseTagMountPoint,
ReparseDataLength = 0,
PathBuffer = new byte[0x3ff0]
};
var inBufferSize = Marshal.SizeOf(reparseDataBuffer);
var inBuffer = Marshal.AllocHGlobal(inBufferSize);
try {
Marshal.StructureToPtr(reparseDataBuffer, inBuffer, false);
int bytesReturned;
var result = DeviceIoControl(handle.DangerousGetHandle(), FsctlDeleteReparsePoint,
inBuffer, 8, IntPtr.Zero, 0, out bytesReturned, IntPtr.Zero);
if (!result)
{
ThrowLastWin32Error("Unable to delete junction point.");
}
} finally {
Marshal.FreeHGlobal(inBuffer);
}
try {
Directory.Delete(junctionPoint);
} catch (IOException ex) {
throw new IOException("Unable to delete junction point.", ex);
}
}
}
