RE: [PATCH] posix/tst-getaddrinfo4: Consider EAI_NODATA as an expected result

[Alexey Brodkin <Alexey dot Brodkin at synopsys dot com>]

Hi Florian,

> -----Original Message-----
> From: linux-snps-arc <linux-snps-arc-bounces@lists.infradead.org> On Behalf Of Florian Weimer
> Sent: Wednesday, April 24, 2019 3:50 PM
> To: Alexey Brodkin <abrodkin@synopsys.com>
> Cc: linux-snps-arc@lists.infradead.org; libc-alpha@sourceware.org
> Subject: Re: [PATCH] posix/tst-getaddrinfo4: Consider EAI_NODATA as an expected result
> 
> * Alexey Brodkin:
> 
> > Hi Florian,
> >
> >> -----Original Message-----
> >> From: Florian Weimer <fweimer@redhat.com>
> >> Sent: Thursday, April 18, 2019 3:08 PM
> >> To: Alexey Brodkin <abrodkin@synopsys.com>
> >> Cc: libc-alpha@sourceware.org; linux-snps-arc@lists.infradead.org
> >> Subject: Re: [PATCH] posix/tst-getaddrinfo4: Consider EAI_NODATA as an expected result
> >>
> >> * Alexey Brodkin:
> >>
> >> > Some proxy DNS servers might not resolve IPv6 names to addresses.
> >> > Instead they reply with NOERROR while passing no real data.
> >> > That combination of NOERROR and EAI_NODATA happen because the DNS
> >> > server has a recored for requested name (example.net in our case)
> >> > but that record is not of AAAA type which was requested.
> >>
> >> I think this invalidates the test to a large degree.  I don't think this
> >> is a valid test environment.  You need to fix it.
> >
> > I think more interesting would be to figure out if behavior that I see
> > is valid or not and then decide which test is representative.
> 
> The test was added for this bug:
> 
>   getaddrinfo returns EAI_SYSTEM instead of EAI_NONAME when the network is down
>   <https://urldefense.proofpoint.com/v2/url?u=https-3A__sourceware.org_bugzilla_show-5Fbug.cgi-3Fid-
> 3D15339&d=DwICAg&c=DPL6_X_6JkXFx7AXWqB0tg&r=lqdeeSSEes0GFDDl656eViXO7breS55ytWkhpk5R81I&m=sC1flmdXCo0K
> _9eK__8gRyau_7kSpT32orktcQ2LNeQ&s=TlbAE45sBJja6y8F5OAcODgAOWc1Lx9MYQLP0_iOQSQ&e=>
> 
> So I think the return code from getaddrinfo matters here.
> 
> We could switch to a namespace with disabled networking; this way, the
> test would perhaps be more reliable.
> 
> I also think the test is wrong.  EAI_NONAME indicates (negative)
> success, something that should not happen if networking is disabled.

That makes perfect sense, thanks for explanation.
So I guess there's no point in spending any more time on that test now.

-Alexey