#include <wmiguid.h>

NTSTATUS status;
GUID smbiosGUID = SMBIOS_DATA_GUID; // defined in wmiguid.h
PVOID wmiObject = NULL;
PWNODE_ALL_DATA dataBuffer;

//
// Get a WMI block handle to the SMBIOS_DATA_GUID
//
status = IoWMIOpenBlock( (GUID *) &smbiosGUID, WMIGUID_QUERY,
&wmiObject );

if (!NT_SUCCESS(status)) {
  return status;
}

//
// Determine how much space is required for the data
//
status = IoWMIQueryAllData( wmiObject, &bufferSize, NULL );
if (status != STATUS_BUFFER_TOO_SMALL) {
  ObDereferenceObject( wmiObject );
  return status;
}

//
// Allocate the necessary storage. This space must come out of NP-pool
//
dataBuffer = ExAllocatePoolWithTag(NonPagedPool, bufferSize, TAG_SMBIOS);
if (dataBuffer == NULL) {
  ObDereferenceObject( wmiObject );
  return STATUS_INSUFFICIENT_RESOURCES;
}