eventshare.c

Sample code that demostrates how to use shared events in Kernel mode.

///////////////////////////////////////////////////////////////////////////////
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//
//    MODULE:
//
//        EventShare.C -- Event Share example user mode component
//
//    ABSTRACT:
//
//       This is a console application that simply creates a named event,
//	   	  sends an IOCTL to the event share driver to open a handle
//		  to the event, and waits for the driver to signal the event
//
//    AUTHOR(S):
//
//        OSR Open Systems Resources, Inc.
// 
//    REVISION:   
//
//
///////////////////////////////////////////////////////////////////////////////
#include <windows.h>
#include <winioctl.h>
#include "..\inc\eventioctl.h"
#include <stdio.h>

int main(void) 
{
	DWORD		bytesReturned;
	DWORD		WaitStatus;

	HANDLE		DeviceDriver;
	HANDLE		SharedEvent;

	//
	// Open up a handle to the device driver
	//
    DeviceDriver = CreateFile(
					"\\\\.\\EventShare",                // lpFileName
					GENERIC_READ | GENERIC_WRITE,       // dwDesiredAccess
					FILE_SHARE_READ | FILE_SHARE_WRITE, // dwShareMode
					NULL,                               // lpSecurityAttributes
					OPEN_EXISTING,                      // dwCreationDistribution
					0,                                  // dwFlagsAndAttributes
					NULL                                // hTemplateFile
					);

	if (DeviceDriver == INVALID_HANDLE_VALUE) {

		printf("Unable to open handle to the device driver\n");
		return 1;

	}

	//
	// Create named event that will be shared between the driver and
	// application. Note that this event is actually created under 
	// \BaseNamedObjects\ by the object manager so we will need to add 
	// that to the event name when we try and open this event from kernel mode
	//
	SharedEvent = CreateEvent(NULL, TRUE, FALSE, "SharedEvent");
	
	if (SharedEvent == NULL) {

		printf("Cannot create named event!\n");
		return 1;
	
	}

	//
	// Send an IOCTL to the driver to signal that the named event
	// has been created and that it can now open a handle to it
	//
	if (!DeviceIoControl(DeviceDriver, 
						 IOCTL_OPEN_EVENT, 
						 NULL, 0, 
						 NULL, 0, 
				 		 &bytesReturned, 
						 NULL)) {

		printf("The driver failed to open the named event!\n");
		return 1;

	}

	//
	// Now we can just sit back and wait for the driver to signal our event.
	// It should really happen well before 5 seconds...
	//
	WaitStatus = WaitForSingleObject(SharedEvent, 5000);

	if (WaitStatus != WAIT_OBJECT_0) {

		printf("Driver failed to signal event! WaitForSingleObject returned 0x%8.8x\n", 
			WaitStatus);

	} else {

		//
		// Voila! We've successfully awoken a user mode application by signalling 
		// an event in kernel mode!
		//
		printf("The driver has successfully signaled our named event!\n");

	}

	//
	// Clean up any and all resources allocated
	//
	CloseHandle(SharedEvent);
	CloseHandle(DeviceDriver);
	
	return 0;

}