Question

I wanna write a program that should perform some tasks automatically if someone logs onto my server.

My questions regarding this are:

• 1) Is there a last login record that
  is set right after a user logs in
  that I can use/monitor for my
  purpose? If not is there something
  similar I can use?

• 2) What’s the best way to constantly
  monitor such a value?

Answer 1

Your best (and by far safest) bet is to create a service that accepts the SERVICE_CONTROL_SESSIONCHANGE control.

This will allow your service control handler to receive a control whenever a user logs on, logs off, locks the session, and various other options. Look for more info in a link blow.

This is done by creating a service which has the SERVICE_ACCEPT_SESSIONCHANGE flag in the dwControlsAccepted, as following:

SERVICE_STATUS ss;
...
ss.dwControlsAccepted |= SERVICE_ACCEPT_SESSIONCHANGE;

Followed by:

// This lets the service accept the session change ctrls
// The service handle here is received by calling RegisterServiceCtrlHandler
SetServiceStatus(hServiceHandle,
                 &ss);

This will allow windows to send SERVICE_CONTROL_SESSIONCHANGE controls to your HandlerEx function, which should look something like this:

DWORD WINAPI HandlerEx(DWORD dwControl,
                       DWORD dwEventType, 
                       LPVOID lpEventData, 
                       LPVOID lpContext)
{
   switch (dwControl)
   {
    ...// Regular control handling
       case (SERVICE_CONTROL_SESSIONCHANGE):
            switch(dwEventType)
            {
                case(WTS_SESSION_LOGON):
                    // Handle logon
                break;

                case(WTS_SESSION_LOCK):
                    // Handle lock
                break;
                ...
            }
       break;

       ...
   }
}

You can read up on all the different session change notifications you can receive from here: WM_WTSSESSION_CHANGE, all the notifications you’ll need are in the wParam part of the description.

Well, that’s the gist of it anyway. You can read more info on the handlerex function here: HandlerEx and more information about services in general here: Service Functions. I suggest you read up on the ServiceMain function, RegisterServiceCtrlHandler function and, most importantly, read the examples posted on the MSDN pages. They’re super helpful.

Good luck!