/*++

Copyright (c) Microsoft Corporation.  All rights reserved.

    THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY
    KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
    IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR
    PURPOSE.

Module Name:

    wmi.c

Abstract: This module demonstrates how to receive WMI notification fired by
          another driver. The code here basically registers for toaster
          device arrival WMI notification fired by the toaster function driver.
          You can use similar technique to receive media sense notification
          (GUID_NDIS_STATUS_MEDIA_CONNECT/GUID_NDIS_STATUS_MEDIA_DISCONNECT)
          fired by NDIS whenever the network cable is plugged or unplugged.

Environment:

    Kernel mode


--*/

#include "toastmon.h"
#include "public.h"
#include <wmistr.h>

//
// These typedefs required to avoid compilation errors in Win2K build environment.
//
typedef
VOID
(*WMI_NOTIFICATION_CALLBACK)( // Copied from WDM.H
    PVOID Wnode,
    PVOID Context
    );

typedef
NTSTATUS
(*PFN_IO_WMI_OPEN_BLOCK)(
    IN  GUID   * DataBlockGuid,
    IN  ULONG    DesiredAccess,
    OUT PVOID  * DataBlockObject
    );

typedef
NTSTATUS
(*PFN_IO_WMI_SET_NOTIFICATION_CALLBACK)(
    IN PVOID                      Object,
    IN WMI_NOTIFICATION_CALLBACK  Callback,
    IN PVOID                      Context
    );

NTSTATUS
GetTargetFriendlyName(
    WDFIOTARGET Target,
    IN WDFMEMORY* TargetName
    );

#ifdef ALLOC_PRAGMA
#pragma alloc_text(PAGE, RegisterForWMINotification)
#pragma alloc_text(PAGE, UnregisterForWMINotification)
#pragma alloc_text(PAGE, GetTargetFriendlyName)
#pragma alloc_text(PAGE, WmiNotificationCallback)
#endif


NTSTATUS
RegisterForWMINotification(
    PDEVICE_EXTENSION DeviceExt
    )
{
    NTSTATUS           status = STATUS_SUCCESS;
    GUID               wmiGuid;
    UNICODE_STRING     funcName;

    PFN_IO_WMI_OPEN_BLOCK                 WmiOpenBlock;
    PFN_IO_WMI_SET_NOTIFICATION_CALLBACK  WmiSetNotificationCallback;

    PAGED_CODE();

    //
    // APIs  to open WMI interfaces are available on XP and beyond, so let us
    // first check to see whether there are exported in the kernel we are
    // running before using them.
    //
    RtlInitUnicodeString(&funcName, L"IoWMIOpenBlock");

    WmiOpenBlock =
        (PFN_IO_WMI_OPEN_BLOCK) (ULONG_PTR)
            MmGetSystemRoutineAddress(&funcName);

    RtlInitUnicodeString(&funcName, L"IoWMISetNotificationCallback");

    WmiSetNotificationCallback =
        (PFN_IO_WMI_SET_NOTIFICATION_CALLBACK) (ULONG_PTR)
            MmGetSystemRoutineAddress(&funcName);

    if(WmiOpenBlock == NULL || WmiSetNotificationCallback == NULL) {
        //
        // Not available.
        //
        return STATUS_NOT_SUPPORTED;
    }

    //
    // Check to make sure we are not called multiple times.
    //
    ASSERT(DeviceExt->WMIDeviceArrivalNotificationObject == NULL);

    //
    // Register WMI callbacks for toaster device arrival events
    //
    wmiGuid = TOASTER_NOTIFY_DEVICE_ARRIVAL_EVENT;

    status = WmiOpenBlock(
                 &wmiGuid,
                 WMIGUID_NOTIFICATION,
                 &DeviceExt->WMIDeviceArrivalNotificationObject
                 );
    if (!NT_SUCCESS(status)) {

        KdPrint(("Unable to open wmi data block status 0x%x\n", status));
        DeviceExt->WMIDeviceArrivalNotificationObject = NULL;

    } else {

        status = WmiSetNotificationCallback(
                     DeviceExt->WMIDeviceArrivalNotificationObject,
                     WmiNotificationCallback,
                     DeviceExt
                     );
        if (!NT_SUCCESS(status)) {
            KdPrint(("Unable to register for wmi notification 0x%x\n", status));
            ObDereferenceObject(DeviceExt->WMIDeviceArrivalNotificationObject);
            DeviceExt->WMIDeviceArrivalNotificationObject = NULL;
        }
    }

    return status;
}


VOID
UnregisterForWMINotification(
    PDEVICE_EXTENSION DeviceExt
)
{
    PAGED_CODE();

    if (DeviceExt->WMIDeviceArrivalNotificationObject != NULL) {
        ObDereferenceObject(DeviceExt->WMIDeviceArrivalNotificationObject);
        DeviceExt->WMIDeviceArrivalNotificationObject = NULL;
    }
}


NTSTATUS
GetTargetFriendlyName(
    WDFIOTARGET Target,
    IN WDFMEMORY* TargetName
    )
/*++

Routine Description:

    Return the friendly name associated with the given device object.

Arguments:

Return Value:

    NT status

--*/
{
    NTSTATUS status;

    PAGED_CODE();

    //
    // First get the length of the string. If the FriendlyName
    // is not there then get the lenght of device description.
    //
    status = WdfIoTargetAllocAndQueryTargetProperty(Target,
                                                    DevicePropertyFriendlyName,
                                                    NonPagedPool,
                                                    WDF_NO_OBJECT_ATTRIBUTES,
                                                    TargetName);

    if (!NT_SUCCESS(status) && status != STATUS_INSUFFICIENT_RESOURCES) {
        status = WdfIoTargetAllocAndQueryTargetProperty(Target,
                                                        DevicePropertyDeviceDescription,
                                                        NonPagedPool,
                                                        WDF_NO_OBJECT_ATTRIBUTES,
                                                        TargetName);

    }

    if (!NT_SUCCESS(status)) {
        KdPrint(("WdfDeviceQueryProperty returned %x\n", status));
    }

    return status;
}

VOID
WmiNotificationCallback(
    IN PVOID Wnode,
    IN PVOID Context
    )
/*++

Routine Description:

    WMI calls this function to notify the caller that the specified event has occurred.

Arguments:

    Wnode - points to the WNODE_EVENT_ITEM structure returned by the driver triggering the event.

    Context - points to the value specified in the Context parameter of the
                    IoWMISetNotificationCallback routine.

Return Value:

    NT status

--*/
{
    PWNODE_SINGLE_INSTANCE wnode = (PWNODE_SINGLE_INSTANCE) Wnode;
    WDFMEMORY memory;
    UNICODE_STRING deviceName;
    PDEVICE_OBJECT devobj;
    NTSTATUS status;
    PDEVICE_EXTENSION deviceExt = Context;
    WDFCOLLECTION hCollection = deviceExt->TargetDeviceCollection;
    WDFIOTARGET ioTarget;
    ULONG i;

    PAGED_CODE();

    WdfWaitLockAcquire(deviceExt->TargetDeviceCollectionLock, NULL);

    for(i=0; i< WdfCollectionGetCount(hCollection); i++){

        ioTarget = WdfCollectionGetItem(hCollection, i);

        //
        // Before calling WdfIoTargetWdmGetTargetDeviceObject, make sure the target is still open.
        // The WdfIoTargetWdmGetXxxDeviceObject APIs can only be called while the target is opened, otherwise
        // they can return undefined values.
        //
        if (GetTargetDeviceInfo(ioTarget)->Opened == FALSE) {
            KdPrint(("WDFIOTARGET %p not in an opened state.\n", ioTarget));
            continue;
        }

        devobj = WdfIoTargetWdmGetTargetDeviceObject(ioTarget);

        if(devobj &&
            IoWMIDeviceObjectToProviderId(devobj) == wnode->WnodeHeader.ProviderId) {

            if( IsEqualGUID( (LPGUID)&(wnode->WnodeHeader.Guid),
                          (LPGUID)&TOASTER_NOTIFY_DEVICE_ARRIVAL_EVENT) ) {
                //
                // found the device. Just for demonstration, get the friendlyname of the
                // target device and print it.
                //
                status = GetTargetFriendlyName(ioTarget, &memory);
                if (!NT_SUCCESS(status)) {
                    KdPrint(("GetDeviceFriendlyName returned %x\n", status));
                    break;
                }

                RtlInitUnicodeString(&deviceName, (PWSTR) WdfMemoryGetBuffer(memory, NULL));
                KdPrint(("%wZ fired a device arrival event\n", &deviceName));

                //
                // Free the memory allocated by GetDeviceFriendlyName.
                //
                WdfObjectDelete(memory);

                break;

            } else {
                KdPrint(("Unknown event.\n"));
            }
        }

    }

    WdfWaitLockRelease(deviceExt->TargetDeviceCollectionLock);
}