Question

As per MSDN, http://msdn.microsoft.com/en-us/library/ms646302%28VS.85%29.aspx

GetLastInputInfo does not provide
system-wide user input information
across all running sessions. Rather,
GetLastInputInfo provides
session-specific user input
information for only the session that
invoked the function.

Is there something similar which provides a system-wide last user input information?

Answer 1

I believe the only way to do this is through hooking into the shell.

This is (obviously) something that must be done carefully and is something not feasible in managed code until this is fully supported by the operating system (not till windows 7) so you will have to use some unmanaged code to achieve this, perhaps updating some global state queryable from your managed code. The API for this is SetWindowsHookEx.

With the session isolation of Vista onwards you will need elevated priviledges to do this for other sessions. In this taking cues from how keyloggers work may help but I do not have a ready link to some source for this.

As a first start here is the source from the windows port of condor for spotting keyboard activity:

/***************************************************************
 *
 * Copyright (C) 1990-2007, Condor Team, Computer Sciences Department,
 * University of Wisconsin-Madison, WI.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License"); you
 * may not use this file except in compliance with the License.  You may
 * obtain a copy of the License at
 * 
 *    http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 ***************************************************************/


#include <windows.h>

// Shared DATA
// put in here data that is needed globally
#pragma data_seg(".SHARDATA")
HHOOK hHook = NULL;
LONG KBkeyhitflag = 0;
#pragma data_seg()
#pragma comment(linker, "/SECTION:.SHARDATA,RWS")

__declspec(dllexport) LRESULT CALLBACK KBHook(int nCode, WPARAM wParam,
LPARAM lParam)
{
    InterlockedExchange(&KBkeyhitflag,1);

    return CallNextHookEx(hHook,nCode,wParam,lParam);
}

HINSTANCE g_hinstDLL = NULL;

#if defined(__cplusplus)
extern "C" {
#endif //__cplusplus


int __declspec( dllexport) WINAPI KBInitialize(void)
{
    hHook=(HHOOK)SetWindowsHookEx(WH_KEYBOARD,(HOOKPROC)KBHook,g_hinstDLL,0);
    return hHook ? 1 : 0;
}

int __declspec( dllexport) WINAPI KBShutdown(void)
{
    if ( UnhookWindowsHookEx(hHook) )
        return 1;   // success
    else
        return 0;   // failure
}

int __declspec( dllexport)  WINAPI KBQuery(void)
{
    if ( InterlockedExchange(&KBkeyhitflag,0) )
        return 1;   // a key has been hit since last query
    else
        return 0;   // no keys hit since asked last
}

#if defined(__cplusplus)
} // extern "C"
#endif //defined(__cplusplus)

BOOL WINAPI DllMain(HANDLE hInstDLL, ULONG fdwReason, LPVOID lpReserved)
{
    switch (fdwReason)
    {
        case DLL_PROCESS_ATTACH:
            g_hinstDLL = (HINSTANCE)hInstDLL;
            DisableThreadLibraryCalls(g_hinstDLL);
            break;
    }
    return 1;
}