/// <summary>
/// Constructs a new USN helper instance
/// </summary>
/// <param name="path">The path to the folder to perform USN services</param>
/// <param name="volumeRoot">The root volume where the USN lookup is performed</param>
internal USNHelper(string path, string volumeRoot)
{
if (Utility.IsClientLinux)
{
throw new Exception("LinuxNotSupportedError");
}
if (!System.IO.Path.IsPathRooted(path))
{
throw new Exception(string.Format("Path {0} is not rooted", path));
}
m_path = Utility.AppendDirSeparator(path);
try
{
string devicename = @"\\.\" + System.IO.Path.GetPathRoot(path).TrimEnd('\\');
if (volumeRoot != null)
{
volumeRoot = volumeRoot.TrimEnd('\\');
}
m_volumeHandle = Win32USN.CreateFile(volumeRoot == null ? devicename : volumeRoot, Win32USN.EFileAccess.GenericRead, Win32USN.EFileShare.ReadWrite, IntPtr.Zero, Win32USN.ECreationDisposition.OpenExisting, Win32USN.EFileAttributes.BackupSemantics, IntPtr.Zero);
if (m_volumeHandle == null || m_volumeHandle.IsInvalid)
{
throw new Win32Exception(Marshal.GetLastWin32Error());
}
uint bytesReturned = 0;
if (!Win32USN.DeviceIoControl(m_volumeHandle, Win32USN.EIOControlCode.FsctlQueryUsnJournal, null, 0, out m_journal, (uint)Marshal.SizeOf(typeof(Win32USN.USN_JOURNAL_DATA)), ref bytesReturned, IntPtr.Zero))
{
throw new Win32Exception(Marshal.GetLastWin32Error());
}
Win32USN.BY_HANDLE_FILE_INFORMATION fileInfo;
using (SafeFileHandle driveHandle = Win32USN.CreateFile(System.IO.Path.GetPathRoot(path), Win32USN.EFileAccess.GenericRead, Win32USN.EFileShare.ReadWrite, IntPtr.Zero, Win32USN.ECreationDisposition.OpenExisting, Win32USN.EFileAttributes.BackupSemantics, IntPtr.Zero))
if (!Win32USN.GetFileInformationByHandle(driveHandle, out fileInfo))
{
throw new Win32Exception(Marshal.GetLastWin32Error());
}
m_volumeRootFileNameReferenceNumber = ((ulong)fileInfo.FileIndexHigh << 32) | ((ulong)fileInfo.FileIndexLow);
}
catch
{
if (m_volumeHandle != null)
{
m_volumeHandle.Dispose();
m_volumeHandle = null;
}
throw;
}
if (this.FileSystemEntries.Count == 0)
{
throw new Exception("SafeGuardError");
}
}
/// <summary>
/// Unused internal function that can be used to read all USN records
/// </summary>
/// <param name="lastUsn">The USN number to start from</param>
private void GetChangedItems(long lastUsn)
{
const int ALLOCATED_MEMORY = 64 * 1024;
IntPtr allocatedMemory = IntPtr.Zero;
List <KeyValuePair <string, Win32USN.USN_RECORD> > records = new List <KeyValuePair <string, Win32USN.USN_RECORD> >();
try
{
uint bytesRead = 0;
bool more = true;
allocatedMemory = Marshal.AllocHGlobal(ALLOCATED_MEMORY);
Win32USN.READ_USN_JOURNAL_DATA startParams = new Win32USN.READ_USN_JOURNAL_DATA();
startParams.UsnJournalID = m_journal.UsnJournalID;
startParams.StartUsn = lastUsn;
startParams.ReasonMask = Win32USN.USNReason.USN_REASON_ANY;
startParams.ReturnOnlyOnClose = 0;
startParams.Timeout = 0;
startParams.BytesToWaitFor = 0;
while (more)
{
if (!Win32USN.DeviceIoControl(m_volumeHandle, Win32USN.EIOControlCode.FsctlReadUsnJournal,
startParams, (uint)Marshal.SizeOf(typeof(Win32USN.READ_USN_JOURNAL_DATA)),
allocatedMemory, ALLOCATED_MEMORY,
ref bytesRead, IntPtr.Zero))
{
int errorCode = Marshal.GetLastWin32Error();
//If we get no error or EOF the enumeration is completed
if (errorCode == Win32USN.ERROR_HANDLE_EOF || errorCode == Win32USN.ERROR_SUCCESS)
{
break;
}
else
{
throw new Win32Exception(errorCode);
}
}
startParams.StartUsn = ExtractUsnEntries(bytesRead, allocatedMemory, records, out more);
}
//Records now contains all Usn entries
}
finally
{
if (allocatedMemory != IntPtr.Zero)
{
Marshal.FreeHGlobal(allocatedMemory);
allocatedMemory = IntPtr.Zero;
}
}
}
/// <summary>
/// Returns a list of all files and folders changed since the USN
/// </summary>
/// <param name="startUsn">The USN number to start the list from, set to zero to get all</param>
/// <returns>A list of files and folders changed since the USN</returns>
private List <KeyValuePair <string, Win32USN.USN_RECORD> > BuildUSNTable(long startUsn)
{
const int ALLOCATED_MEMORY = 64 * 1024;
IntPtr allocatedMemory = IntPtr.Zero;
List <KeyValuePair <string, Win32USN.USN_RECORD> > records = new List <KeyValuePair <string, Win32USN.USN_RECORD> >();
try
{
uint bytesRead = 0;
bool more = true;
allocatedMemory = Marshal.AllocHGlobal(ALLOCATED_MEMORY);
Win32USN.MFT_ENUM_DATA startParams = new Win32USN.MFT_ENUM_DATA();
startParams.StartFileReferenceNumber = 0;
startParams.LowUsn = Math.Max(startUsn, m_journal.LowestValidUsn);
startParams.HighUsn = m_journal.NextUsn;
while (more)
{
if (!Win32USN.DeviceIoControl(m_volumeHandle, Win32USN.EIOControlCode.FsctlEnumUsnData,
ref startParams, (uint)Marshal.SizeOf(typeof(Win32USN.MFT_ENUM_DATA)),
allocatedMemory, ALLOCATED_MEMORY,
ref bytesRead, IntPtr.Zero))
{
int errorCode = Marshal.GetLastWin32Error();
//If we get no error or EOF the enumeration is completed
if (errorCode == Win32USN.ERROR_HANDLE_EOF || errorCode == Win32USN.ERROR_SUCCESS)
{
break;
}
else
{
throw new Win32Exception(errorCode);
}
}
startParams.StartFileReferenceNumber = (ulong)ExtractUsnEntries(bytesRead, allocatedMemory, records, out more);
}
return(ParseRecordList(records));
}
finally
{
if (allocatedMemory != IntPtr.Zero)
{
Marshal.FreeHGlobal(allocatedMemory);
allocatedMemory = IntPtr.Zero;
}
}
}