Re: [PATCH 2/2] tests/9pfs: fix coverity error in create_local_test_dir()

[Christian Schoenebeck]

On Freitag, 30. Oktober 2020 12:44:18 CET Greg Kurz wrote:
> On Fri, 30 Oct 2020 09:19:46 +0100
> 
> Christian Schoenebeck <qemu_oss@crudebyte.com> wrote:
> > Coverity wants the return value of mkdir() to be checked, so let's
> > pretend to do that. We're actually just making a dummy check and
> > ignore the result, because we actually only care if the required
> > directory exists and we have an existence check for that in place
> > already.
> 
> I see that sometimes changelog shows a copy of the original
> coverity report (e.g. commit df1a312fea58).

Ok, I'll add that.

> > Reported-by: Greg Kurz <groug@kaod.org>
> 
> Please give credits to coverity, not me :-)
> 
> And most importantly, we want to mention the CID in the changelog.
> 
> e.g.
> 
> Reported-by: Coverity (CID 1435963)

Ok.

It's not clear to me where this coverity report is accessible online. A quick 
search only brought me to statistics about its latest check, but not the 
details of the report you quoted.

And more importantly: is there coverity CI support that one could enable on 
github, so that pending patches were checked before upstream merge?

> 
> > Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com>
> > ---
> > 
> >  tests/qtest/libqos/virtio-9p.c | 6 +++++-
> >  1 file changed, 5 insertions(+), 1 deletion(-)
> > 
> > diff --git a/tests/qtest/libqos/virtio-9p.c
> > b/tests/qtest/libqos/virtio-9p.c index 6b22fa0e9a..0a7c0ee5d8 100644
> > --- a/tests/qtest/libqos/virtio-9p.c
> > +++ b/tests/qtest/libqos/virtio-9p.c
> > @@ -48,9 +48,13 @@ static void init_local_test_path(void)
> > 
> >  static void create_local_test_dir(void)
> >  {
> >  
> >      struct stat st;
> > 
> > +    int res;
> > 
> >      g_assert(local_test_path != NULL);
> > 
> > -    mkdir(local_test_path, 0777);
> > +    res = mkdir(local_test_path, 0777);
> > +    if (res < 0) {
> > +        /* ignore error, dummy check to prevent error by coverity */
> 
> Why not printing an error message with errno there like you did in
> the previous patch ?

Yeah, originally I didn't want to trigger false positives on automated CIs if 
mkdir() failed just because the directory already exists. But OTOH 
g_test_message() is just an info-level message, so it is Ok to bark silently 
and I will add it.

> 
> > +    }
> > 
> >      /* ensure test directory exists now ... */
> >      g_assert(stat(local_test_path, &st) == 0);

Thanks!

Best regards,
Christian Schoenebeck