WMI_SET_DATAITEM_CALLBACK callback function (wmilib.h)

Article
10/21/2021

The DpWmiSetDataItem routine changes a single data item in an instance of a data block. This routine is optional.

Syntax

WMI_SET_DATAITEM_CALLBACK WmiSetDataitemCallback;

NTSTATUS WmiSetDataitemCallback(
  [in] PDEVICE_OBJECT DeviceObject,
  [in] PIRP Irp,
  [in] ULONG GuidIndex,
  [in] ULONG InstanceIndex,
  [in] ULONG DataItemId,
  [in] ULONG BufferSize,
  [in] PUCHAR Buffer
)
{...}

Parameters

[in] DeviceObject

Pointer to the driver's WDM DEVICE_OBJECT structure.

[in] Irp

Pointer to the IRP.

[in] GuidIndex

Specifies the data block by supplying a zero-based index into the list of GUIDs that the driver provided in the WMILIB_CONTEXT structure it passed to WmiSystemControl.

[in] InstanceIndex

If the block specified by GuidIndex has multiple instances, InstanceIndex is a zero-based value that specifies the instance.

[in] DataItemId

Specifies the ID of the data item to set.

[in] BufferSize

Specifies the size in bytes of the buffer at Buffer.

[in] Buffer

Pointer to a buffer that contains the new value for the data item.

Return value

DpWmiSetDataItem returns STATUS_SUCCESS or an appropriate error code such as the following:

Remarks

WMI calls a driver's DpWmiSetDataItem routine after the driver calls WmiSystemControl in response to an IRP_MN_CHANGE_SINGLE_ITEM request.

Do not implement DpWmiSetDataItem unless you are sure that a system-supplied user-mode component requires this capability. If you implement a DpWmiSetDataItem routine, the driver must place the routine's address in the SetWmiDataItem member of the WMILIB_CONTEXT structure that it passes to WmiSystemControl. If you do not implement a DpWmiSetDataItem routine, the driver must set SetWmiDataItem to NULL. In the latter case, WMI returns STATUS_READ_ONLY to the caller.

The driver is responsible for validating all input arguments. Specifically, the driver must do the following:

Verify that the GuidIndex value is between zero and GuidCount-1, based on the GuidCount member of the WMILIB_CONTEXT structure.
Verify that the driver has not flagged the specified data block for removal. If the driver recently specified the WMIREG_FLAG_REMOVE_GUID flag in a WMIGUIDREGINFO structure that is contained in a WMILIB_CONTEXT structure, it is possible for a set request to arrive before the removal occurs.
Verify that the InstanceIndex value is within the range of instance indexes that are supported by the driver for the data block.
Verify that the DataItemId value is within the range of data item identifiers that are supported by the driver for the data block.
Verify that Buffer and BufferSize describe a valid-sized data item, and that the contents of the buffer are valid for the data item.
Verify that the specified data item is one for which the driver allows caller-initiated modifications. In other words, the driver should not allow modifications to data items that you intended to be read-only.

Do not assume the thread context is that of the initiating user-mode application—a higher-level driver might have changed it.

This routine can be pageable.

For more information about implementing this routine, see Calling WmiSystemControl to Handle WMI IRPs.

Requirements

Requirement	Value
Target Platform	Desktop
Header	wmilib.h (include Wmilib.h)
IRQL	Called at PASSIVE_LEVEL.