fix for getipnodebyname(3)

[Jacques A. Vidrine]

On Mon, Apr 05, 2004 at 07:34:24PM +0200, Pierre Beyssac wrote:
> getipnodebyname(3) as it stands in FreeBSD 4 and 5 has a problem
> with nameserver timeouts or misconfiguration.
> 
> Symptom: getipnodebyname(3) lookups in unreachable/unconfigured
> zones return h_errno=HOST_NOT_FOUND instead of h_errno=TRY_AGAIN.
> 
> It causes email to bounce at least with sendmail, which is quite
> annoying.
> 
> Unless someone objects to it, I'd like to commit the following fix
> to current later today. Since FreeBSD 4 is impacted too, the patch
> will have to be adapted and MFC'd some day.
> 
> The only potential problem I see with my patch is that it accesses
> h_errno, which is possibly not thread-safe. Could someone please
> shed some light on this for me?
> 
> Pierre
> 
> --- name6.c.old	Wed Feb 25 23:27:17 2004
> +++ name6.c	Mon Apr  5 14:19:31 2004
> @@ -1565,7 +1565,8 @@
>  					continue;
>  				hp = _hpcopy(&hpbuf, errp);
>  				hp0 = _hpmerge(hp0, hp, errp);
> -			}
> +			} else
> +				*errp = h_errno;
>  		}
>  		if (hp0 != NULL) {
>  			free(buf);
> @@ -1604,7 +1605,8 @@
>  						continue;
>  					hp = _hpcopy(&hpbuf, errp);
>  					hp0 = _hpmerge(hp0, hp, errp);
> -				}
> +				} else
> +					*errp = h_errno;
>  			}
>  			if (hp0 != NULL) {
>  				free(buf);
> @@ -1677,7 +1679,8 @@
>  					continue;
>  				hp = _hpcopy(&hpbuf, errp);
>  				hp0 = _hpmerge(hp0, hp, errp);
> -			}
> +			} else
> +				*errp = h_errno;
>  		}
>  		if (hp0 != NULL) {
>  			free(buf);
> @@ -1739,7 +1742,12 @@
>  	rtl = &rtl4;
>  #endif
>  	*(struct hostent **)rval = _res_search_multi(name, rtl, errp);
> -	return (*(struct hostent **)rval != NULL) ? NS_SUCCESS : NS_NOTFOUND;
> +	if (*(struct hostent **)rval != NULL)
> +		return NS_SUCCESS;
> +	else if (*errp == TRY_AGAIN)
> +		return NS_TRYAGAIN;
> +	else
> +		return NS_NOTFOUND;
>  }
>  
>  static int

This fix looks correct to me.

Hey, Pierre, one wonders why you bothered posting a patch for review if
you were just going to commit it less than 3 hours later?  Please allow
more time next time.

Good catch, BTW :-)

Cheers,
-- 
Jacques Vidrine / nectar at celabo.org / jvidrine at verio.net / nectar at freebsd.org