[libvirt] [PATCH] domain: Fix crash if trying to live update disk <serial>

[Cole Robinson]

On 08/11/2015 05:25 PM, John Ferlan wrote:
> 
> 
> On 08/10/2015 07:33 PM, Cole Robinson wrote:
>> If you pass <disk><serial> XML to UpdateDevice, and the original device
>> didn't have a <serial> block, libvirtd crashes trying to read the original
>> NULL serial string.
>>
>> Use _NULLABLE string comparisons to avoid the crash. A couple other
>> properties needed the change too.
>> ---
>>  src/conf/domain_conf.c | 8 ++++----
>>  1 file changed, 4 insertions(+), 4 deletions(-)
>>
> 
> Using STRNEQ_NULLABLE means you probably don't have to check the disk->*
> value either, right?
> 
> ACK - with that adjustment...
> 

It would change the semantic a bit; if the orig disk has a <serial>, but not
the XML passed to UpdateDevice, libvirt would now error where previously it
wouldn't. It might make sense but I didn't want to change behavior

- Cole

> John
>> diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
>> index fd0450f..f1e02e3 100644
>> --- a/src/conf/domain_conf.c
>> +++ b/src/conf/domain_conf.c
>> @@ -5871,28 +5871,28 @@ virDomainDiskDiffersSourceOnly(virDomainDiskDefPtr disk,
>>  
>>      CHECK_EQ(transient, "transient", true);
>>  
>> -    if (disk->serial && STRNEQ(disk->serial, orig_disk->serial)) {
>> +    if (disk->serial && STRNEQ_NULLABLE(disk->serial, orig_disk->serial)) {
>>          virReportError(VIR_ERR_OPERATION_UNSUPPORTED,
>>                         _("cannot modify field '%s' of the disk"),
>>                         "serial");
>>          return false;
>>      }
>>  
>> -    if (disk->wwn && STRNEQ(disk->wwn, orig_disk->wwn)) {
>> +    if (disk->wwn && STRNEQ_NULLABLE(disk->wwn, orig_disk->wwn)) {
>>          virReportError(VIR_ERR_OPERATION_UNSUPPORTED,
>>                         _("cannot modify field '%s' of the disk"),
>>                         "wwn");
>>          return false;
>>      }
>>  
>> -    if (disk->vendor && STRNEQ(disk->vendor, orig_disk->vendor)) {
>> +    if (disk->vendor && STRNEQ_NULLABLE(disk->vendor, orig_disk->vendor)) {
>>          virReportError(VIR_ERR_OPERATION_UNSUPPORTED,
>>                         _("cannot modify field '%s' of the disk"),
>>                         "vendor");
>>          return false;
>>      }
>>  
>> -    if (disk->product && STRNEQ(disk->product, orig_disk->product)) {
>> +    if (disk->product && STRNEQ_NULLABLE(disk->product, orig_disk->product)) {
>>          virReportError(VIR_ERR_OPERATION_UNSUPPORTED,
>>                         _("cannot modify field '%s' of the disk"),
>>                         "product");
>>