netdev - Re: [v3 2/3] samples: pktgen: add helper functions for IP(v4/v6) CIDR parsing

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Message-ID: <20190916085317.02e4d985@carbon>
Date:   Mon, 16 Sep 2019 08:53:17 +0200
From:   Jesper Dangaard Brouer <brouer@...hat.com>
To:     "Daniel T. Lee" <danieltimlee@...il.com>
Cc:     "David S . Miller" <davem@...emloft.net>, netdev@...r.kernel.org,
        brouer@...hat.com,
        Toke Høiland-Jørgensen <toke@...hat.com>
Subject: Re: [v3 2/3] samples: pktgen: add helper functions for IP(v4/v6)
 CIDR parsing

On Sun, 15 Sep 2019 00:13:52 +0900
"Daniel T. Lee" <danieltimlee@...il.com> wrote:

> This commit adds CIDR parsing and IP validate helper function to parse
> single IP or range of IP with CIDR. (e.g. 198.18.0.0/15)
> 
> Helpers will be used in prior to set target address in samples/pktgen.
> 
> Signed-off-by: Daniel T. Lee <danieltimlee@...il.com>
> ---
> Changes since v3:
>  * Set errexit option to stop script execution on error
> 
>  samples/pktgen/functions.sh | 124 ++++++++++++++++++++++++++++++++++++
>  1 file changed, 124 insertions(+)
> 
> diff --git a/samples/pktgen/functions.sh b/samples/pktgen/functions.sh
> index 4af4046d71be..87ae61701904 100644
> --- a/samples/pktgen/functions.sh
> +++ b/samples/pktgen/functions.sh
> @@ -5,6 +5,8 @@
>  # Author: Jesper Dangaaard Brouer
>  # License: GPL
>  
> +set -o errexit

Unfortunately, this breaks the scripts.

The function proc_cmd are designed to grep after "Result: OK:" which
might fail, and your patch/change makes the script stop immediately.
We actually want to continue, and output what command that failed (and
also grep again after "Result:" to provide the kernel reason).

Even if you somehow "fix" function proc_cmd, then we in general want to
catch different error situations by looking at status $?, and output
meaning full errors via calling err() function.  IHMO as minimum with
errexit you need a 'trap' function that can help/inform the user of
what went wrong.

-- 
Best regards,
  Jesper Dangaard Brouer
  MSc.CS, Principal Kernel Engineer at Red Hat
  LinkedIn: http://www.linkedin.com/in/brouer