Re: [ros-dev] [ros-diffs] [janderwald] 73016: [USBAUDIO] - implement retrieving string descriptor of product and store it in registry.

[Thomas Faber]

On 2016-10-21 23:15, [e-mail] wrote:
> NTSTATUS
> +NTAPI
> +USBAudioGetDescriptor(
> IN PDEVICE_OBJECT DeviceObject,
> IN UCHAR DescriptorType,
> IN ULONG DescriptorLength,
> IN UCHAR DescriptorIndex,
> IN LANGID LanguageId,
> OUT PVOID *OutDescriptor)
>
> +{
> PURB Urb;
> NTSTATUS Status;
> PVOID Descriptor;
> /* sanity checks */
> ASSERT(DeviceObject);
> ASSERT(OutDescriptor);
> ASSERT(DescriptorLength);
> //
> // first allocate descriptor buffer
> //
> Descriptor = AllocFunction(DescriptorLength);
> if (!Descriptor)
> {
>    /* no memory */
>    return STATUS_INSUFFICIENT_RESOURCES;
> }
> /* allocate urb */
> Urb = (PURB)AllocFunction(sizeof(URB));
> if (!Urb)
> {
>    /* no memory */
>    FreeFunction(Descriptor);
>    return STATUS_INSUFFICIENT_RESOURCES;
> }
> /* initialize urb */
> UsbBuildGetDescriptorRequest(Urb,
>    sizeof(Urb->UrbControlDescriptorRequest),
>    DescriptorType,
>    DescriptorIndex,
>    LanguageId,
>    Descriptor,
>    NULL,
>    DescriptorLength,
>    NULL);
> /* submit urb */
> Status = SubmitUrbSync(DeviceObject, Urb);
> /* free urb */
> FreeFunction(Urb);
> if (NT_SUCCESS(Status))
> {
>    /* store result */
>    *OutDescriptor = Descriptor;
> }

Is Descriptor leaked in the failure case, or does something down the
stack take care of that?
> /* done */
> return Status;
>
> +}
> +NTSTATUS
> +USBAudioRegCreateMediaCategoriesKey(
> IN PUNICODE_STRING Name,
> OUT PHANDLE OutHandle)
>
> +{
> NTSTATUS Status;
> OBJECT_ATTRIBUTES ObjectAttributes;
> UNICODE_STRING DestinationString;
> HANDLE Handle;
> /* initialize root name*/
> RtlInitUnicodeString(&DestinationString, L"\Registry\Machine\SYSTEM\CurrentControlSet\Control\MediaCategories\");
> /* initialize object attributes */
> InitializeObjectAttributes(&ObjectAttributes, &DestinationString, OBJ_CASE_INSENSITIVE | OBJ_OPENIF, NULL, NULL);

You're missing OBJ_KERNEL_HANDLE.
> /* create the key */
> Status = ZwOpenKey(&Handle, KEY_ALL_ACCESS, &ObjectAttributes);
> if (NT_SUCCESS(Status))
> {
>    /* initialize object attributes */
>    InitializeObjectAttributes(&ObjectAttributes, Name, OBJ_CASE_INSENSITIVE, Handle, NULL);

Here too.
>    Status = ZwCreateKey(OutHandle, KEY_ALL_ACCESS, &ObjectAttributes, 0, NULL, 0, NULL);
>    ZwClose(Handle);
> }
> return Status;
>
> +}

Thanks.
-Thomas