//-----------------------------------------------------------------------
// Gets the target path for a reparse point
private static void GetTarget(ref ReparsePoint rp)
{
string wPath = rp.Path;
if (!wPath.StartsWith(@"\\?\"))
{
wPath = @"\\?\" + wPath;
}
if (((uint)rp.TagType & (uint)ReparseTagType.IO_REPARSE_TAG_MOUNT_POINT) != (uint)ReparseTagType.IO_REPARSE_TAG_MOUNT_POINT)
{
rp.Target = "";
return;
}
try
{
// We need a handle to the reparse point to pass to DeviceIocontrol down below.
// CreateFile is how we get that handle.
// We want to play nice with others, so we note that we're only reading it, and we want to
// allow others to be able to access (but not delete) it as well while we have the handle (the
// GENERIC_READ and FILE_SHARE_READ | FILE_SHARE_WRITE values)
//
// Biggest key is the flag FILE_FLAG_OPEN_REPARSE_POINT, which tells CreateFile that we want
// a handle to the reparse point itself and not to the target of the reparse point
//
// CreateFile will return INVALID_HANDLE_VALUE with a last error of 5 - Access Denied
// if the FILE_FLAG_BACKUP_SEMANTICS is not specified when opening a directory/reparse point
// It's noted in the directory section of the CreateFile MSDN page
IntPtr pathHndl = CreateFileW(wPath, GENERIC_READ, FILE_SHARE_READ | FILE_SHARE_WRITE, IntPtr.Zero,
OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS | FILE_FLAG_OPEN_REPARSE_POINT, IntPtr.Zero);
if (pathHndl.ToInt32() == INVALID_HANDLE_VALUE)
{
rp.Err = Marshal.GetLastWin32Error();
rp.ErrMsg = "Invalid Handle returned by CreateFile";
rp.Target = "";
return;
}
uint lenDataReturned = 0;
REPARSE_DATA_BUFFER rpDataBuf = new REPARSE_DATA_BUFFER();
//Allocate a buffer to get the "user defined data" out of the reaprse point.
//MSDN page on FSCTL_GET_REPARSE_POINT discusses size calculation
IntPtr pMem = Marshal.AllocHGlobal(Marshal.SizeOf(rpDataBuf) + ReparseHeaderSize);
//DeviceIocontrol takes a handle to a file/directory/device etc, that's obtained via CreateFile
// In our case, it's a handle to the directory that's marked a reparse point
//We pass in the FSCTL_GET_REPARSE_POINT flag to getll DeviceIoControl that we want to get data about a reparse point
//There is no In buffer. pMem is our out buffer that will hold the returned REPARSE_DATA_BUFFER
//lenDataReturned is of course how much data was copied into our buffer pMem.
//We're doing a simple call.. no asyncronous stuff going on, so Overlapped is a null pointer
if (!DeviceIoControl(pathHndl, FSCTL_GET_REPARSE_POINT, IntPtr.Zero, 0, pMem,
(uint)Marshal.SizeOf(rpDataBuf) + ReparseHeaderSize, out lenDataReturned, IntPtr.Zero))
{
rp.ErrMsg = "Call to DeviceIoControl failed";
rp.Err = Marshal.GetLastWin32Error();
rp.Target = "";
}
else
{
rpDataBuf = (REPARSE_DATA_BUFFER)Marshal.PtrToStructure(pMem, rpDataBuf.GetType());
rp.Target = rpDataBuf.PathBuffer;
}
Marshal.FreeHGlobal(pMem);
CloseHandle(pathHndl);
}
catch (Exception e)
{
rp.Err = -1;
rp.ErrMsg = e.Message;
rp.Target = "";
}
return;
}
//-----------------------------------------------------------------------
// Gets the target path for a reparse point
private static void GetTarget(ref ReparsePoint rp)
{
string wPath = rp.Path;
if (!wPath.StartsWith(@"\\?\")) wPath = @"\\?\" + wPath;
if (((uint)rp.TagType & (uint)ReparseTagType.IO_REPARSE_TAG_MOUNT_POINT) != (uint)ReparseTagType.IO_REPARSE_TAG_MOUNT_POINT)
{
rp.Target = "";
return;
}
try
{
// We need a handle to the reparse point to pass to DeviceIocontrol down below.
// CreateFile is how we get that handle.
// We want to play nice with others, so we note that we're only reading it, and we want to
// allow others to be able to access (but not delete) it as well while we have the handle (the
// GENERIC_READ and FILE_SHARE_READ | FILE_SHARE_WRITE values)
//
// Biggest key is the flag FILE_FLAG_OPEN_REPARSE_POINT, which tells CreateFile that we want
// a handle to the reparse point itself and not to the target of the reparse point
//
// CreateFile will return INVALID_HANDLE_VALUE with a last error of 5 - Access Denied
// if the FILE_FLAG_BACKUP_SEMANTICS is not specified when opening a directory/reparse point
// It's noted in the directory section of the CreateFile MSDN page
IntPtr pathHndl = CreateFileW(wPath, GENERIC_READ, FILE_SHARE_READ | FILE_SHARE_WRITE, IntPtr.Zero,
OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS | FILE_FLAG_OPEN_REPARSE_POINT, IntPtr.Zero);
if (pathHndl.ToInt32() == INVALID_HANDLE_VALUE)
{
rp.Err = Marshal.GetLastWin32Error();
rp.ErrMsg = "Invalid Handle returned by CreateFile";
rp.Target = "";
return;
}
uint lenDataReturned = 0;
REPARSE_DATA_BUFFER rpDataBuf = new REPARSE_DATA_BUFFER();
//Allocate a buffer to get the "user defined data" out of the reaprse point.
//MSDN page on FSCTL_GET_REPARSE_POINT discusses size calculation
IntPtr pMem = Marshal.AllocHGlobal(Marshal.SizeOf(rpDataBuf) + ReparseHeaderSize);
//DeviceIocontrol takes a handle to a file/directory/device etc, that's obtained via CreateFile
// In our case, it's a handle to the directory that's marked a reparse point
//We pass in the FSCTL_GET_REPARSE_POINT flag to getll DeviceIoControl that we want to get data about a reparse point
//There is no In buffer. pMem is our out buffer that will hold the returned REPARSE_DATA_BUFFER
//lenDataReturned is of course how much data was copied into our buffer pMem.
//We're doing a simple call.. no asyncronous stuff going on, so Overlapped is a null pointer
if (!DeviceIoControl(pathHndl, FSCTL_GET_REPARSE_POINT, IntPtr.Zero, 0, pMem,
(uint)Marshal.SizeOf(rpDataBuf) + ReparseHeaderSize, out lenDataReturned, IntPtr.Zero))
{
rp.ErrMsg = "Call to DeviceIoControl failed";
rp.Err = Marshal.GetLastWin32Error();
rp.Target = "";
}
else
{
rpDataBuf = (REPARSE_DATA_BUFFER)Marshal.PtrToStructure(pMem, rpDataBuf.GetType());
rp.Target = rpDataBuf.PathBuffer;
}
Marshal.FreeHGlobal(pMem);
CloseHandle(pathHndl);
}
catch (Exception e)
{
rp.Err = -1;
rp.ErrMsg = e.Message;
rp.Target = "";
}
return;
}
