[PATCH 03/13] resolv: Add internal __res_binary_hnok function

[Siddhesh Poyarekar]

On 2022-08-10 05:30, Florian Weimer via Libc-alpha wrote:
> ---
>   include/resolv.h           |  3 +++
>   resolv/res-name-checking.c | 14 +++++++++-----
>   2 files changed, 12 insertions(+), 5 deletions(-)

OK but it would be nice to have a commit log that references any future 
uses, explaining why this function is needed.

Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>

> diff --git a/include/resolv.h b/include/resolv.h
> index 3590b6f496..4dbbac3800 100644
> --- a/include/resolv.h
> +++ b/include/resolv.h
> @@ -70,5 +70,8 @@ libc_hidden_proto (__libc_res_nameinquery)
>   extern __typeof (__res_queriesmatch) __libc_res_queriesmatch;
>   libc_hidden_proto (__libc_res_queriesmatch)
>   
> +/* Variant of res_hnok which operates on binary (but uncompressed) names.  */
> +bool __res_binary_hnok (const unsigned char *dn) attribute_hidden;
> +
>   # endif /* _RESOLV_H_ && !_ISOMAC */
>   #endif
> diff --git a/resolv/res-name-checking.c b/resolv/res-name-checking.c
> index 07a412d8ff..213edceaf3 100644
> --- a/resolv/res-name-checking.c
> +++ b/resolv/res-name-checking.c
> @@ -138,6 +138,12 @@ binary_leading_dash (const unsigned char *dn)
>     return dn[0] > 0 && dn[1] == '-';
>   }
>   
> +bool
> +__res_binary_hnok (const unsigned char *dn)
> +{
> +  return !binary_leading_dash (dn) && binary_hnok (dn);
> +}
> +
>   /* Return 1 if res_hnok is a valid host name.  Labels must only
>      contain [0-9a-zA-Z_-] characters, and the name must not start with
>      a '-'.  The latter is to avoid confusion with program options.  */
> @@ -145,11 +151,9 @@ int
>   ___res_hnok (const char *dn)
>   {
>     unsigned char buf[NS_MAXCDNAME];
> -  if (!printable_string (dn)
> -      || __ns_name_pton (dn, buf, sizeof (buf)) < 0
> -      || binary_leading_dash (buf))
> -    return 0;
> -  return binary_hnok (buf);
> +  return (printable_string (dn)
> +	  && __ns_name_pton (dn, buf, sizeof (buf)) >= 0
> +	  && __res_binary_hnok (buf));
>   }
>   versioned_symbol (libc, ___res_hnok, res_hnok, GLIBC_2_34);
>   versioned_symbol (libc, ___res_hnok, __libc_res_hnok, GLIBC_PRIVATE);