/// <summary>
/// Create an unknown state list for a named reader
/// </summary>
/// <remarks>
/// Sets the currentState and eventState to 'Unaware' for the reader
/// </remarks>
/// <param name="readerName">Reader name for which to create initial state</param>
/// <returns>List of unknown reader states</returns>
private SmartcardInterop.ScardReaderState CreatePendingReaderState(string readerName)
{
var state = new SmartcardInterop.ScardReaderState
{
reader = readerName,
currentState = SmartcardInterop.State.Unaware,
eventState = 0,
atrLength = 0
};
return(state);
}
/// <summary>
/// Call the card removed delegate for each changed reader
/// </summary>
/// <param name="state">State class containing the smartcard reader name</param>
private void FireCardRemovedEvent(SmartcardInterop.ScardReaderState state)
{
if (this.DebounceState(state.reader, CardEvent.Remove))
{
return;
}
var args = new SmartcardEventArgs(null, state.reader);
this.logger.DebugFormat("Firing card removed event for reader {0}", state.reader);
this.OnCardRemoved?.Invoke(this, args);
}
/// <summary>
/// Call the card detected delegate for each changed reader
/// </summary>
/// <param name="state">State class containing the smartcard reader name</param>
private void FireCardPresentEvent(SmartcardInterop.ScardReaderState state)
{
if (this.DebounceState(state.reader, CardEvent.Insert))
{
return;
}
var cardname = this.FindCardWithAtr(state.atr);
var scard = new Smartcard(state.reader, cardname);
var args = new SmartcardEventArgs(scard, state.reader);
this.logger.DebugFormat("Firing card insert event for reader {0}, card {1}", state.reader, cardname);
this.OnCardInserted?.Invoke(this, args);
}
/// <summary>
/// Monitor for smartcard change events and fire events on detected changes
/// </summary>
private void WaitForReaderStateChange()
{
var awaitNewReader = new SmartcardInterop.ScardReaderState
{
reader = NotificationReader,
currentState = 0,
eventState = 0,
atrLength = 0
};
this.currentState.Add(awaitNewReader);
var i = 0;
var result = 0;
while (!this.cancelToken.IsCancellationRequested)
{
try
{
i++;
var scardstate = this.currentState.ToArray();
this.logger.DebugFormat("StateChange - start: {0}; last status = 0x{1}; statecount = {2}", i, result.ToString("X"), scardstate.Length);
// We have a 30 second timeout rather than infinite. As of Windows 8, the smartcard
// service shuts down if no readers attached and more than a couple of minutes have
// elapsed since the last SCard API call. So a 30 second timeout will keep the service
// alive and mean we're not reseting context (and thus restarting smartcard service)
// every couple of minutes.
result = SmartcardInterop.SCardGetStatusChange(this.readerContext, 30000, scardstate, scardstate.Length);
if (this.cancelToken.IsCancellationRequested || result == SmartcardException.SCardECancelled)
{
this.logger.Debug("Cancellation requested");
break;
}
if (result == SmartcardException.SCardETimeout)
{
continue;
}
this.logger.Debug("StateChange - result: 0x" + result.ToString("X"));
var scardstatelist = scardstate.ToList();
// If the service has stopped, then we need to flag all existing cards as removed
if (this.HandleStoppedService(scardstatelist, result))
{
// Need to reset the smartcard context
this.ResetContext();
this.currentState.Add(awaitNewReader);
continue;
}
// All other errors, throw an exception
if (result != SmartcardException.SCardSuccess)
{
this.logger.DebugFormat("Failed to get smartcard state: error 0x{0}", result);
throw new SmartcardException(result);
}
// Now deal with the actual smartcard changes
var scardChanges = scardstatelist.Where(x => (x.eventState & SmartcardInterop.State.Changed) != 0).ToList();
if (scardChanges.Count == 0)
{
continue;
}
this.DumpState(scardChanges);
this.HandleRemovedReaders(scardChanges, result);
this.HandleRemovedCards(scardChanges, result);
this.HandleInsertedCards(ref scardChanges, result);
this.SaveState(scardChanges);
}
catch (SmartcardException ex)
{
if (ex.Status == SmartcardException.SCardEServiceStopped || ex.Status == SmartcardException.SCardENoService)
{
this.logger.Debug("Smartcard service stopped; resetting context");
this.ResetContext();
this.currentState.Add(awaitNewReader);
}
else
{
throw;
}
}
}
this.logger.Debug("Monitoring stopped.");
}
