[libvirt] [PATCH 09/11] storage_scsi: Allow the direct PCI address for 'parent'

[Osier Yang]

On 20/06/13 15:04, Ján Tomko wrote:
> On 06/20/2013 05:21 AM, Osier Yang wrote:
>> On 20/06/13 02:28, John Ferlan wrote:
>>> On 06/07/2013 01:16 PM, Osier Yang wrote:
>>>> On 08/06/13 01:03, Osier Yang wrote:
>>>>>             return NULL;
>>>>>         }
>>>>>     -    if (!(tokens = virStringSplit(parent, "_", 0)))
>>>>> -        return NULL;
>>>>> +    if (strchr(parent, '_')) {
>>>>> +        if (!(tokens = virStringSplit(parent, "_", 0)))
>>>>> +            return NULL;
>>>>>     -    len = virStringListLength(tokens);
>>>>> +        length = virStringListLength(tokens);
>>>>> +
>>>>> +        switch (length) {
>>>>> +        case 4:
>>>>> +            if (!(ret = virStringJoin((const char **)(&tokens[1]),
>>>>> ":")))
>>>>> +                goto cleanup;
>>>>> +            break;
>>>>>     -    switch (len) {
>>>>> -    case 4:
>>>>> -        if (!(ret = virStringJoin((const char **)(&tokens[1]), ":")))
>>>>> +        case 2:
>>>>> +            vendor = tokens[1];
>>>>> +            product = tokens[2];
>>>>> +            if (!(ret = virFindPCIDeviceByVPD(NULL, vendor, product))) {
>>>>> +                virReportError(VIR_ERR_INTERNAL_ERROR,
>>>>> +                               _("Unable to find PCI device with
>>>>> vendor '%s' "
>>>>> +                                 "product '%s'"), vendor, product);
>>>>> +                goto cleanup;
>>>>> +            }
>>>>> +
>>>>> +            break;
>>>>> +        default:
>>>>> +            virReportError(VIR_ERR_XML_ERROR, "%s",
>>>>> +                       _("'parent' of scsi_host adapter must be "
>>>>> +                         "either consistent with name of mode "
>>>>> +                         "device, or in domain:bus:slot:function "
>>>>> +                         "format"));
>>> Duplicated error message - same issues as before, plus I think you need
>>> to consider determining which of the two places you got the error.  That
>>> is if we see that message, then did we get an error because there wasn't
>>> a "_" or ":" in the name or (in this case) because the address was
>>> malformed since we expected only 2 or 4 numbers with a specific
>>> separator but found more or less.  In this case, I would think you could
>>> just indicate the parent %s is malformed, requires only 2 or 4 separators.
>>>
>> I don't think so, indicate it requires 2 or 4 separators doesn't give the
>> user what we expect clearly. That's why I use "duplicate" error messages,
>> even if
>>
>> +    if (!strchr(parent, '_') &&
>> +        !strchr(parent, ':')) {
>>
>> is false, we still have to let the user know what the format we expect for
>> "parent" attribute.
>>
>>
>>>>>                 goto cleanup;
>>>>> -        break;
>>>>> +        }
>>>>> +    } else if (strchr(parent, ':')) {
>>>>> +        char *padstr = NULL;
>>>>> +
>>>>> +        if (!(tokens = virStringSplit(parent, ":", 0)))
>>>>> +            return NULL;
>>>>>     -    case 2:
>>>>> -        vendor = tokens[1];
>>>>> -        product = tokens[2];
>>>>> -        if (!(ret = virFindPCIDeviceByVPD(NULL, vendor, product))) {
>>>>> -            virReportError(VIR_ERR_INTERNAL_ERROR,
>>>>> -                           _("Unable to find PCI device with vendor
>>>>> '%s' "
>>>>> -                             "product '%s'"), vendor, product);
>>>>> +        length = virStringListLength(tokens);
>>>>> +
>>>>> +        if (length != 4) {
>>>>> +            virReportError(VIR_ERR_XML_ERROR,
>>>>> +                           _("invalid PCI address for scsi_host "
>>>>> +                             "'parent' '%s'"), parent);
>>>>>                 goto cleanup;
>>>>>             }
>>>>>     -        break;
>>>>> -    default:
>>>>> -        virReportError(VIR_ERR_XML_ERROR, "%s",
>>>>> -                       _("'parent' of scsi_host adapter must "
>>>>> -                         "be consistent with name of node device"));
>>>>> -        goto cleanup;
>>>>> +        for (i = 0; i < length; i++) {
>>>>> +            if (strlen(tokens[i]) == 0) {
>>>>> +                virReportError(VIR_ERR_XML_ERROR,
>>>>> +                               _("invalid PCI address for scsi_host "
>>>>> +                                 "'parent' '%s'"), parent);
>>>>> +                goto cleanup;
>>>>> +            }
>>>>> +        }
>>>>> +
>>>>> +        /* sysfs always exposes the PCI address like "0000:00:1f:2",
>>>>> +         * this do the padding if the address prodived by user is
>>> s/prodived/provided
>>>
>>>>> +         * not padded (e.g. 0:0:2:0).
>>>>> +         */
>>>>> +        if (strlen(tokens[0]) != 4) {
>>>>> +            if (!(padstr = virStringPad(tokens[0], '0', 4, false)))
>>>>> +                goto cleanup;
>>>>> +
>>>>> +            virBufferAsprintf(&buf, "%s", padstr);
>>>>> +            VIR_FREE(padstr);
>>>>> +        } else {
>>>>> +            virBufferAsprintf(&buf, "%s", tokens[0]);
>>>>> +        }
>>>>> +
>>>>> +        for (i = 1; i < 3; i++) {
>>>>> +            if (strlen(tokens[i]) != 2) {
>>>>> +                if (!(padstr = virStringPad(tokens[i], '0', 2, false)))
>>>>> +                    goto error;
>>>>> +                virBufferAsprintf(&buf, "%s", padstr);
>>> I think the following syntax will avoid any sort of virStringPad() and
>>> whatever is going on above
>>>
>>> virBufferAsprintf(&buf, "%04x:02x:02x:%s",
>>>                     atoi(tokens[0]), atoi(tokens[1]),
>>>                     atoi(tokens[2]), tokens[3]);
>>>
>>> Assuming of course that each field is a base16 value and atoi() is "OK"
>>> to use here...
>> glibc says atoi is absolete, and since it's not required to do any error
>> checking, strtol is recommended.
>>
>> In libvirt, we have wrapper for strtol: virStrTo*.
>>
>> But I don't see it's better than using virStringPad if converting the string
>> into int using virStringTo*.  We have to check the return value of virStringTo*
>> anyway here, because the user could input crazy data, e.g.
>>
>> 1234566789101112:01:02:02
>>
>> Osier
>>
> What if we separated the fields in the XML? It feels wrong to store data as a
> string separated by underscores, only to have to parse it again.
>
> Instead of
>    <adapter type='scsi_host' parent='pci_0000_00_1f_2' unique_id='2'/>
> We could do:
>    <adapter type='scsi_host' unique_id='2'>
>      <parent>
>        <address type='pci' domain='0x0000' bus='0x00' slot='0x1f' function='0x2'/>
>      </parent>
>    </adapter>
>
> or:
> <parent>
>    <vendor>0x8086</vendor>
>    <device>0x1e03</device>
> </parent>
>
As the cover letter says, it uses the name what nodedev represents. I 
woudn't
want to store the data in that strange way if nodedev doesn't reresent 
device
like that.

Osier