+NTSTATUS WINAPI common_pnp_dispatch(DEVICE_OBJECT *device, IRP *irp) +{
- NTSTATUS rc = STATUS_NOT_SUPPORTED;
You generally want to initialize this with irp->IoStatus.Status. For requests the bus driver doesn't support, it needs to return whatever the drivers higher up the stack decided. E.g. IRP_MN_QUERY_DEVICE_RELATIONS might be handled by a bus driver FDO above, in which case it will likely set the status to success -- and lower-level drivers need to propagate this status unless they have specific reason to override it.
This is the reason for the requirement to initialize IoStatus to STATUS_NOT_SUPPORTED when sending the IRP.
- IO_STACK_LOCATION *irpsp = IoGetCurrentIrpStackLocation(irp);
- switch(irpsp->MinorFunction)
- {
case IRP_MN_QUERY_DEVICE_RELATIONS:TRACE("IRP_MN_QUERY_DEVICE_RELATIONS\n");break;case IRP_MN_QUERY_ID:{TRACE("IRP_MN_QUERY_ID\n");break;}case IRP_MN_QUERY_CAPABILITIES:TRACE("IRP_MN_QUERY_CAPABILITIES\n");break;- }
- IoCompleteRequest( irp, IO_NO_INCREMENT );
- return rc;
+}
+DWORD check_bus_disabled(UNICODE_STRING *registry_path) +{
- OBJECT_ATTRIBUTES attr;
- HANDLE key;
- DWORD disabled = 0;
- static const WCHAR disabledW[] = {'D','i','s','a','b','l','e','d',0};
- static const UNICODE_STRING disabled_str = {sizeof(disabledW) - sizeof(WCHAR), sizeof(disabledW), (WCHAR*)disabledW};
- InitializeObjectAttributes(&attr, registry_path, OBJ_CASE_INSENSITIVE, NULL, NULL);
This is another case for OBJ_KERNEL_HANDLE. You basically want this by default in kernel code, unless you specifically intend to pass this handle to an application.
- if (ZwOpenKey(&key, KEY_ALL_ACCESS, &attr) == STATUS_SUCCESS)
- {
DWORD size;KEY_VALUE_PARTIAL_INFORMATION info;if (ZwQueryValueKey(key, &disabled_str, KeyValuePartialInformation, &info, sizeof(info), &size) == STATUS_SUCCESS)
Your 'info' structure isn't large enough to hold DWORD data, since the 'Data' member is a one byte array.
{disabled = *(DWORD*)&info.Data;}ZwClose(key);- }
- return disabled;
+}