From: "Theo de Raadt" <deraadt@openbsd.org>
Subject: Re: arp: print errno on failure
To: Klemens Nanni <kn@openbsd.org>
Cc: OpenBSD tech <tech@openbsd.org>
Date: Thu, 09 Apr 2026 16:12:48 -0600

You are not showing how it looks, or what errors it shows.  If the
errors it shows are completely redundant information, then this is
pointless.  But why should we do the work of doing that? Did you
leave that information out intentionally?

> Here's an old diff, I don't remember whether I hit it or it just stood out.
> 
> getifaddrs(3) sets errno and arp.c:send_frame() also returns it,
> only for errx(3) to throw it away;  that seems wrong.
> 
> Feedback? OK?
> 
> Less braces/return make it a net negative diff.
> 
> Index: arp.c
> ===================================================================
> RCS file: /cvs/src/usr.sbin/arp/arp.c,v
> diff -u -p -r1.89 arp.c
> --- arp.c	4 Apr 2023 21:18:04 -0000	1.89
> +++ arp.c	4 Nov 2025 23:25:12 -0000
> @@ -808,7 +808,7 @@ wake(const char *ether_addr, const char 
>  
>  	if (iface == NULL) {
>  		if (getifaddrs(&ifa) == -1)
> -			errx(1, "Could not get interface addresses.");
> +			err(1, "Could not get interface addresses");
>  
>  		for (ifap = ifa; ifap != NULL; ifap = ifap->ifa_next){
>  			if (pname && !strcmp(pname, ifap->ifa_name))
> @@ -848,7 +848,7 @@ do_wakeup(const char *eaddr, const char 
>  	if (bind_if_to_bpf(iface, bpf) != 0)
>  		errx(1, "Failed to bind %s to bpf.", iface);
>  	if (send_frame(bpf, &macaddr) != 0)
> -		errx(1, "Failed to send WoL frame on %s", iface);
> +		err(1, "Failed to send WoL frame on %s", iface);
>  	return 0;
>  }
>  
> @@ -880,10 +880,8 @@ get_ether(const char *text, struct ether
>  	if (eaddr == NULL) {
>  		if (ether_hostton(text, addr))
>  			return -1;
> -	} else {
> +	} else
>  		*addr = *eaddr;
> -		return 0;
> -	}
>  
>  	return 0;
>  }
>