Re: [XENBUS PATCH 2/2] Be more tolerant of RealTimeIsUniversal values

[Owen Smith <owen.smith@xxxxxxxxx>]

    status = SystemGetTimeInformation();
    if (!NT_SUCCESS(status))
        Error("Cannot read RealTimeIsUniversal, clock may be incorrect!\n");

doesnt log the error code, and still returns STATUS_SUCCESS from this function (SystemInitialize).

Owen

On Wed, Aug 13, 2025 at 5:12 PM Tu Dinh <ngoc-tu.dinh@xxxxxxxxxx> wrote:

On 13/08/2025 18:09, Owen Smith wrote:
>
>
> On Wed, Aug 13, 2025 at 2:32 PM Tu Dinh <ngoc-tu.dinh@xxxxxxxxxx> wrote:
>
>
>     -    status = RegistryQueryDwordValue(Key, "RealTimeIsUniversal",
>     -                                     &RealTimeIsUniversal);
>     -    if (!NT_SUCCESS(status)) {
>     -        if (status != STATUS_OBJECT_NAME_NOT_FOUND)
>     -            goto fail2;
>     +    status = RegistryQueryDwordValue(Key, "RealTimeIsUniversal",
>     &ValueDword);
>     +    if (status == STATUS_OBJECT_NAME_NOT_FOUND) {
>     +        Context->RealTimeIsUniversal = FALSE;
>     +        goto done;
>     +    } else if (NT_SUCCESS(status)) {
>     +        Context->RealTimeIsUniversal = !!ValueDword;
>     +        goto done;
>     +    }
>
>     -        RealTimeIsUniversal = 0;
>     +    status = RegistryQueryQwordValue(Key, "RealTimeIsUniversal",
>     &ValueQword);
>     +    if (NT_SUCCESS(status)) {
>     +        Context->RealTimeIsUniversal = !!ValueQword;
>     +        goto done;
>           }
>
>     -    Context->RealTimeIsUniversal = RealTimeIsUniversal ? TRUE : FALSE;
>     +    status = STATUS_UNSUCCESSFUL;
>     +    Context->RealTimeIsUniversal = FALSE;
>
>     +done:
>           Info("%s\n", Context->RealTimeIsUniversal ? "TRUE" : "FALSE");
>
> The logic here seems more complicated than required. Would something like
>
>      status = RegistryQueryDwordValue(Key, "RealTimeIsUniversal",
> &ValueDword);
>      if (NT_SUCCESS(status)) {
>          Context->RealTimeIsUniversal = !!ValueDword;
>          goto done;
>      }
>
>      status = RegistryQueryQwordValue(Key, "RealTimeIsUniversal",
> &ValueQword);
>      if (NT_SUCCESS(status)) {
>          Context->RealTimeIsUniversal = !!ValueQword;
>          goto done;
>      }
>
>      Context->RealTimeIsUniversal = FALSE;
>
> done:
>      Info("%s\n", Context->RealTimeIsUniversal ? "TRUE" : "FALSE");
>
> be cleaner?
>
> Owen
>

I didn't want SystemGetTimeInformation to error out when the
RealTimeIsUniversal value is absent since its status code is used later
on for error reporting. But I can also ignore the status code of
SystemGetTimeInformation instead. What do you prefer?


Ngoc Tu Dinh | Vates XCP-ng Developer

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