[libvirt] [PATCH] qemu: Avoid memleak on failure to format blockjobs

[Michal Privoznik]

On 10/18/2018 10:42 PM, Eric Blake wrote:
> On 10/18/18 3:08 PM, Eric Blake wrote:
>> virXMLFormatElement() frees attrBuf on success, but not necessarily
>> on failure. Most other callers of this function take the time to
>> reset attrBuf afterwords, but qemuDomainObjPrivateXMLFOrmatBlockjobs()
>> was relying on it succeeding, and could thus result in a memory leak.
>>
>> Signed-off-by: Eric Blake <eblake at redhat.com>
>> ---
>>   src/qemu/qemu_domain.c | 6 +++++-
>>   1 file changed, 5 insertions(+), 1 deletion(-)
>>
>> diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
>> index dd67be5e2a..ad7a6fe136 100644
>> --- a/src/qemu/qemu_domain.c
>> +++ b/src/qemu/qemu_domain.c
>> @@ -2232,11 +2232,15 @@
>> qemuDomainObjPrivateXMLFormatBlockjobs(virBufferPtr buf,
>>   {
>>       virBuffer attrBuf = VIR_BUFFER_INITIALIZER;
>>       bool bj = qemuDomainHasBlockjob(vm, false);
>> +    ret = -1;
> 
> I need to quit editing patches in my mailer. As written, this obviously
> doesn't compile; s/ret/int ret/
> 
>>
>>       virBufferAsprintf(&attrBuf, " active='%s'",
>>                        
>> virTristateBoolTypeToString(virTristateBoolFromBool(bj)));
>>
>> -    return virXMLFormatElement(buf, "blockjobs", &attrBuf, NULL);
>> +    ret = virXMLFormatElement(buf, "blockjobs", &attrBuf, NULL);
>> + cleanup:
> 
> and this label is unused.
> 
>> +    virBufferFreeAndReset(&attrBuf);
>> +    return ret;
>>   }
>>
>>
> 

ACK with those cleanups squashed in.

Michal