[libvirt] [PATCH REBASE 3/5] utils: export virCopyError

[Nikolay Shirokovskiy]

On 04.05.2018 16:58, John Ferlan wrote:
> 
> 
> On 05/03/2018 03:39 AM, Nikolay Shirokovskiy wrote:
>>
>>
>> On 01.05.2018 01:03, John Ferlan wrote:
>>>
>>>
>>> On 04/18/2018 10:44 AM, Nikolay Shirokovskiy wrote:
>>>> Signed-off-by: Nikolay Shirokovskiy <nshirokovskiy at virtuozzo.com>
>>>> ---
>>>>  src/libvirt_private.syms |  1 +
>>>>  src/util/virerror.c      | 12 +++++++++---
>>>>  src/util/virerror.h      |  1 +
>>>>  3 files changed, 11 insertions(+), 3 deletions(-)
>>>>
>>>
>>> NACK, you should be using virErrorCopyNew
>>>
>>> John
>>
>> I introduced monError in qemuDomainObjPrivatePtr in next patch and it is not a pointer so
>> I need this function. I did not make monError pointer for the same reason it is not pointer
>> in monitor object - I use monError both as flag and as error message.
>>
> 
> I saw what you did - the fact is virCopyError is coded as private to the
> module. Just making it global because you have a use for it is I believe
> incorrect.

But why?

> 
> Ironically in the next patch you have:
> 
> +    virErrorPtr err = qemuMonitorLastError(mon);
> +
> +    virCopyError(err, &priv->monError);
> 
> 
> The first call isn't guaranteed to set @err and all you're essentially
> doing is wanting to copy from mon->lastError to priv->monError or
> perhaps similar to virCopyLastError.

It is ok that error can turn from non-NULL to NULL on copy due to OOM
conditions or whaever. It is just as in previous patch. We use priv->monError
for 2 purpuses. And thus qemuProcessNotifyMonitorError sets priv->monError.code
explicitly if it still set to VIR_ERR_OK after copy.

> 
> Maybe some new API in virerror.c should handle that.
> 

Not sure we need it at this point. But may be I miss something, please
share your vision in more detail then.

Nikolay

> 
>>>
>>>> diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
>>>> index b31f599..6bbbf77 100644
>>>> --- a/src/libvirt_private.syms
>>>> +++ b/src/libvirt_private.syms
>>>> @@ -1702,6 +1702,7 @@ ebtablesRemoveForwardAllowIn;
>>>>  
>>>>  
>>>>  # util/virerror.h
>>>> +virCopyError;
>>>>  virDispatchError;
>>>>  virErrorCopyNew;
>>>>  virErrorInitialize;
>>>> diff --git a/src/util/virerror.c b/src/util/virerror.c
>>>> index c000b00..2ff8a3e 100644
>>>> --- a/src/util/virerror.c
>>>> +++ b/src/util/virerror.c
>>>> @@ -188,10 +188,16 @@ virErrorGenericFailure(virErrorPtr err)
>>>>  }
>>>>  
>>>>  
>>>> -/*
>>>> - * Internal helper to perform a deep copy of an error
>>>> +/**
>>>> + * virCopyError:
>>>> + * @from: error to copy from
>>>> + * @to: error to copy to
>>>> + *
>>>> + * Copy error fields from @from to @to.
>>>> + *
>>>> + * Returns 0 on success, -1 on failure.
>>>>   */
>>>> -static int
>>>> +int
>>>>  virCopyError(virErrorPtr from,
>>>>               virErrorPtr to)
>>>>  {
>>>> diff --git a/src/util/virerror.h b/src/util/virerror.h
>>>> index 760bfa4..90ac619 100644
>>>> --- a/src/util/virerror.h
>>>> +++ b/src/util/virerror.h
>>>> @@ -192,6 +192,7 @@ void virReportOOMErrorFull(int domcode,
>>>>  
>>>>  int virSetError(virErrorPtr newerr);
>>>>  virErrorPtr virErrorCopyNew(virErrorPtr err);
>>>> +int virCopyError(virErrorPtr from, virErrorPtr to);
>>>>  void virDispatchError(virConnectPtr conn);
>>>>  const char *virStrerror(int theerrno, char *errBuf, size_t errBufLen);
>>>>  
>>>>