Re: [PATCH v3 2/5] dumpcap: allow multiple invocations

[Stephen Hemminger <stephen@networkplumber.org>]

On Thu, 9 Nov 2023 08:50:10 +0100
Morten Brørup <mb@smartsharesystems.com> wrote:

> >  			rte_exit(EXIT_FAILURE,
> >  				"Packet dump enable on %u:%s failed %s\n",
> >  				intf->port, intf->name,
> > -				rte_strerror(-ret));
> > +				rte_strerror(rte_errno));  
> 
> This bugfix (the line above, not the patch itself) supports Tyler's proposal to standardize on returning -1 with rte_errno set on failure, instead of some functions returning -errno. Our dual convention for function return values will cause many bugs like this.

The error case here is when rte_pdump_enable_bpf() fails.
This is return from pdump_enable in pdump library.
The library does follow the rte_errno convention correctly.
But the error message wasn't reporting correctly which would lead to confusing error in case where
multiple invocations failed.

It is not possible to do multiple captures on same interface. And not worth modifying the
library (would require multiple copies and ref counts) to handle this case.