[PING,v2,BZ,#14799] Allow to disable options in RES_OPTIONS

  On Sun, Dec 21, 2014 at 05:08:33PM +0100, Andreas Schwab wrote:
> Ondřej Bílka <neleai@seznam.cz> writes:
> 
> > Do you have testcase that shows that?
> 
> I don't need a testcase.  (options[i].clear ^ invert) is obviously
> always nonzero.
> 
Like when you pass inet6 there and options[i].clear == 0 and invert = 0?

But it needs update clear format to match invert.
  

On Sun, Dec 21, 2014 at 05:56:35PM +0100, Ondřej Bílka wrote:
> On Sun, Dec 21, 2014 at 05:08:33PM +0100, Andreas Schwab wrote:
> > Ondřej Bílka <neleai@seznam.cz> writes:
> > 
> > > Do you have testcase that shows that?
> > 
> > I don't need a testcase.  (options[i].clear ^ invert) is obviously
> > always nonzero.
> > 
> Like when you pass inet6 there and options[i].clear == 0 and invert = 0?
> 
> But it needs update clear format to match invert.
> 
> diff --git a/resolv/res_init.c b/resolv/res_init.c
> index d492a08..039116a 100644
> --- a/resolv/res_init.c
> +++ b/resolv/res_init.c
> @@ -527,32 +527,38 @@ res_setoptions(res_state statp, const char *options, const char *source) {
>  		  {
>  		    char str[22];
>  		    uint8_t len;
> -		    uint8_t clear;
> +		    unsigned long clear;
>  		    unsigned long int flag;
>  		  } options[] = {
>  #define STRnLEN(str) str, sizeof (str) - 1
>  		    { STRnLEN ("inet6"), 0, RES_USE_INET6 },
>  		    { STRnLEN ("ip6-bytestring"), 0, RES_USEBSTRING },
> -		    { STRnLEN ("no-ip6-dotint"), 0, RES_NOIP6DOTINT },
> -		    { STRnLEN ("ip6-dotint"), 1, ~RES_NOIP6DOTINT },
> +		    { STRnLEN ("ip6-dotint"), ~0, ~RES_NOIP6DOTINT },
>  		    { STRnLEN ("rotate"), 0, RES_ROTATE },
> -		    { STRnLEN ("no-check-names"), 0, RES_NOCHECKNAME },
> +		    { STRnLEN ("check-names"), ~0, ~RES_NOCHECKNAME },
>  		    { STRnLEN ("edns0"), 0, RES_USE_EDNS0 },
>  		    { STRnLEN ("single-request-reopen"), 0, RES_SNGLKUPREOP },
>  		    { STRnLEN ("single-request"), 0, RES_SNGLKUP },
>  		    { STRnLEN ("no_tld_query"), 0, RES_NOTLDQUERY },
> -		    { STRnLEN ("no-tld-query"), 0, RES_NOTLDQUERY },
> +		    { STRnLEN ("tld-query"), ~0, ~RES_NOTLDQUERY },
>  		    { STRnLEN ("use-vc"), 0, RES_USEVC }
>  		  };
>  #define noptions (sizeof (options) / sizeof (options[0]))
>  		  int i;
> +		  unsigned long int invert = 0;
> +		  if (strncmp (cp, "no-", 3) == 0)
> +		    {
> +		      cp += 3;
> +		      invert = ~0;
> +		    }
> +
>  		  for (i = 0; i < noptions; ++i)
>  		    if (strncmp (cp, options[i].str, options[i].len) == 0)
>  		      {
> -			if (options[i].clear)
> -			  statp->options &= options[i].flag;
> +			if (options[i].clear ^ invert)
> +			  statp->options &= options[i].flag ^ invert;
>  			else
> -			  statp->options |= options[i].flag;
> +			  statp->options |= options[i].flag ^ invert;
>  			break;
>  		      }
>  		  if (i == noptions) {