[PATCH] report error when virProcessGetStatInfo() is unable to parse data

Ani Sinha posted 1 patch 2 weeks, 3 days ago
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git fetch https://github.com/patchew-project/libvirt tags/patchew/20220107090926.222754-1-ani@anisinha.ca
src/util/virprocess.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)

[PATCH] report error when virProcessGetStatInfo() is unable to parse data

Posted by Ani Sinha 2 weeks, 3 days ago
Currently virProcessGetStatInfo() always returns success and only logs error
when it is unable to parse the data. Make this function actually report the
error and return a negative value in this error scenario.

Signed-off-by: Ani Sinha <ani@anisinha.ca>
---
 src/util/virprocess.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/util/virprocess.c b/src/util/virprocess.c
index c74bd16fe6..b9f498d5d8 100644
--- a/src/util/virprocess.c
+++ b/src/util/virprocess.c
@@ -1783,7 +1783,11 @@ virProcessGetStatInfo(unsigned long long *cpuTime,
         virStrToLong_ullp(proc_stat[VIR_PROCESS_STAT_STIME], NULL, 10, &systime) < 0 ||
         virStrToLong_l(proc_stat[VIR_PROCESS_STAT_RSS], NULL, 10, &rss) < 0 ||
         virStrToLong_i(proc_stat[VIR_PROCESS_STAT_PROCESSOR], NULL, 10, &cpu) < 0) {
-        VIR_WARN("cannot parse process status data");
+        virReportError(VIR_ERR_INTERNAL_ERROR,
+                       _("cannot parse process status data for pid '%d/%d'"),
+                       (int) pid, (int) tid);
+
+        return -1;
     }
 
     /* We got jiffies
-- 
2.25.1

Re: [PATCH] report error when virProcessGetStatInfo() is unable to parse data

Posted by Michal Prívozník 2 weeks, 3 days ago
On 1/7/22 10:09, Ani Sinha wrote:
> Currently virProcessGetStatInfo() always returns success and only logs error
> when it is unable to parse the data. Make this function actually report the
> error and return a negative value in this error scenario.
> 
> Signed-off-by: Ani Sinha <ani@anisinha.ca>
> ---
>  src/util/virprocess.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/src/util/virprocess.c b/src/util/virprocess.c
> index c74bd16fe6..b9f498d5d8 100644
> --- a/src/util/virprocess.c
> +++ b/src/util/virprocess.c
> @@ -1783,7 +1783,11 @@ virProcessGetStatInfo(unsigned long long *cpuTime,
>          virStrToLong_ullp(proc_stat[VIR_PROCESS_STAT_STIME], NULL, 10, &systime) < 0 ||
>          virStrToLong_l(proc_stat[VIR_PROCESS_STAT_RSS], NULL, 10, &rss) < 0 ||
>          virStrToLong_i(proc_stat[VIR_PROCESS_STAT_PROCESSOR], NULL, 10, &cpu) < 0) {
> -        VIR_WARN("cannot parse process status data");
> +        virReportError(VIR_ERR_INTERNAL_ERROR,
> +                       _("cannot parse process status data for pid '%d/%d'"),
> +                       (int) pid, (int) tid);
> +
> +        return -1;
>      }
>  
>      /* We got jiffies

Couple of problems with this patch as is. I'm not against the idea of
reporting an error here. But couple of things needs to be addressed first:

1) Currently, all callers check for retval and report an error if -1 was
returned. This means, that even though this new message is reported it
is immediately overwritten in caller.

2) The non-linux implementation now has to report error too. I believe
it's obvious why from our previous discussion this morning.

Michal

Re: [PATCH] report error when virProcessGetStatInfo() is unable to parse data

Posted by Ani Sinha 2 weeks, 3 days ago

On Fri, 7 Jan 2022, Michal Prívozník wrote:

> On 1/7/22 10:09, Ani Sinha wrote:
> > Currently virProcessGetStatInfo() always returns success and only logs error
> > when it is unable to parse the data. Make this function actually report the
> > error and return a negative value in this error scenario.
> >
> > Signed-off-by: Ani Sinha <ani@anisinha.ca>
> > ---
> >  src/util/virprocess.c | 6 +++++-
> >  1 file changed, 5 insertions(+), 1 deletion(-)
> >
> > diff --git a/src/util/virprocess.c b/src/util/virprocess.c
> > index c74bd16fe6..b9f498d5d8 100644
> > --- a/src/util/virprocess.c
> > +++ b/src/util/virprocess.c
> > @@ -1783,7 +1783,11 @@ virProcessGetStatInfo(unsigned long long *cpuTime,
> >          virStrToLong_ullp(proc_stat[VIR_PROCESS_STAT_STIME], NULL, 10, &systime) < 0 ||
> >          virStrToLong_l(proc_stat[VIR_PROCESS_STAT_RSS], NULL, 10, &rss) < 0 ||
> >          virStrToLong_i(proc_stat[VIR_PROCESS_STAT_PROCESSOR], NULL, 10, &cpu) < 0) {
> > -        VIR_WARN("cannot parse process status data");
> > +        virReportError(VIR_ERR_INTERNAL_ERROR,
> > +                       _("cannot parse process status data for pid '%d/%d'"),
> > +                       (int) pid, (int) tid);
> > +
> > +        return -1;
> >      }
> >
> >      /* We got jiffies
>
> Couple of problems with this patch as is. I'm not against the idea of
> reporting an error here.

Good. now we are moving in the right direction.

But couple of things needs to be addressed first:
>
> 1) Currently, all callers check for retval and report an error if -1 was
> returned. This means, that even though this new message is reported it
> is immediately overwritten in caller.

Let me fix the callers and send an updated patch. Meanwhile ...

>
> 2) The non-linux implementation now has to report error too. I believe
> it's obvious why from our previous discussion this morning.

Maybe you can fix your patch.

Re: [PATCH] report error when virProcessGetStatInfo() is unable to parse data

Posted by Michal Prívozník 2 weeks, 3 days ago
On 1/7/22 12:55, Ani Sinha wrote:
> 
> 
> On Fri, 7 Jan 2022, Michal Prívozník wrote:
> 
>> On 1/7/22 10:09, Ani Sinha wrote:
>>> Currently virProcessGetStatInfo() always returns success and only logs error
>>> when it is unable to parse the data. Make this function actually report the
>>> error and return a negative value in this error scenario.
>>>
>>> Signed-off-by: Ani Sinha <ani@anisinha.ca>
>>> ---
>>>  src/util/virprocess.c | 6 +++++-
>>>  1 file changed, 5 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/src/util/virprocess.c b/src/util/virprocess.c
>>> index c74bd16fe6..b9f498d5d8 100644
>>> --- a/src/util/virprocess.c
>>> +++ b/src/util/virprocess.c
>>> @@ -1783,7 +1783,11 @@ virProcessGetStatInfo(unsigned long long *cpuTime,
>>>          virStrToLong_ullp(proc_stat[VIR_PROCESS_STAT_STIME], NULL, 10, &systime) < 0 ||
>>>          virStrToLong_l(proc_stat[VIR_PROCESS_STAT_RSS], NULL, 10, &rss) < 0 ||
>>>          virStrToLong_i(proc_stat[VIR_PROCESS_STAT_PROCESSOR], NULL, 10, &cpu) < 0) {
>>> -        VIR_WARN("cannot parse process status data");
>>> +        virReportError(VIR_ERR_INTERNAL_ERROR,
>>> +                       _("cannot parse process status data for pid '%d/%d'"),
>>> +                       (int) pid, (int) tid);
>>> +
>>> +        return -1;
>>>      }
>>>
>>>      /* We got jiffies
>>
>> Couple of problems with this patch as is. I'm not against the idea of
>> reporting an error here.
> 
> Good. now we are moving in the right direction.
> 
> But couple of things needs to be addressed first:
>>
>> 1) Currently, all callers check for retval and report an error if -1 was
>> returned. This means, that even though this new message is reported it
>> is immediately overwritten in caller.
> 
> Let me fix the callers and send an updated patch. Meanwhile ...
> 
>>
>> 2) The non-linux implementation now has to report error too. I believe
>> it's obvious why from our previous discussion this morning.
> 
> Maybe you can fix your patch.

There is nothing to fix. With current master nor Linux nor non-Linux
variant reports any error, i.e. are consistent. This patch introduced
inconsistency and in my review I have pointed it out. Looking forward to v2.

Michal