[PATCH] resolv: Avoid duplicate query if search list contains '.' (option 2)

[Florian Weimer]

* Carlos Peón Costa:

> This is option 2.
>
> ---
>  resolv/res_query.c | 11 +++++++----
>  1 file changed, 7 insertions(+), 4 deletions(-)
>
> diff --git a/resolv/res_query.c b/resolv/res_query.c
> index 039c25a3c3..30ace9d06d 100644
> --- a/resolv/res_query.c
> +++ b/resolv/res_query.c
> @@ -354,7 +354,7 @@ __res_context_search (struct resolv_context *ctx,
>  	char tmp[NS_MAXDNAME];
>  	u_int dots;
>  	int trailing_dot, ret, saved_herrno;
> -	int got_nodata = 0, got_servfail = 0, root_on_list = 0;
> +	int got_nodata = 0, got_servfail = 0;
>  	int tried_as_is = 0;
>  	int searched = 0;
>  
> @@ -433,8 +433,11 @@ __res_context_search (struct resolv_context *ctx,
>  			   domain.  */
>  			if (dname[0] == '.')
>  				dname++;
> -			if (dname[0] == '\0')
> -				root_on_list++;
> +			if (dname[0] == '\0') {
> +				if (tried_as_is)
> +					continue;
> +				tried_as_is++;
> +			}
>  
>  			ret = __res_context_querydomain
>  			  (ctx, name, dname, class, type,
> @@ -506,7 +509,7 @@ __res_context_search (struct resolv_context *ctx,
>  	 * unless RES_NOTLDQUERY is set and there were no dots.
>  	 */
>  	if ((dots || !searched || (statp->options & RES_NOTLDQUERY) == 0)
> -	    && !(tried_as_is || root_on_list)) {
> +	    && !tried_as_is) {
>  		ret = __res_context_querydomain
>  		  (ctx, name, NULL, class, type,
>  		   answer, anslen, answerp, answerp2, nanswerp2,

What is the intended behavior if "." is present in the search list?

I think it would be useful to change

domain .

and

domain example.com
search .

to disable search list processing.  Is this what other stub resolvers
are already doing?

Thanks,
Florian