[PATCH 21/30] resolv: Move ns_samename into its own file, and into libc

[Carlos O'Donell]

On 7/8/21 11:05 AM, Florian Weimer via Libc-alpha wrote:
> But only as an internal symbol, __libc_ns_samename.  The libresolv
> ABI is preserved.  This is because the function is deprecated, and
> it does not make sense to add new symbol versions for deprecated
> functions.

OK for glibc 2.34.

Tested without regression on x86_64 and i686.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
 
> Also reformat the implementation to GNU style.
> ---
>  include/arpa/nameser.h     |  3 ++-
>  resolv/Makefile            |  1 +
>  resolv/Versions            |  1 +
>  resolv/ns_print.c          |  6 +++---
>  resolv/ns_samedomain.c     | 28 +++-------------------------
>  resolv/ns_samename.c       | 38 ++++++++++++++++++++++++++++++++++++++
>  resolv/res_query.c         |  2 +-
>  resolv/res_send.c          |  4 ++--
>  resolv/resolv-deprecated.c |  6 ++++++
>  9 files changed, 57 insertions(+), 32 deletions(-)
>  create mode 100644 resolv/ns_samename.c
> 
> diff --git a/include/arpa/nameser.h b/include/arpa/nameser.h
> index a529cc86d3..53f1dbc7c3 100644
> --- a/include/arpa/nameser.h
> +++ b/include/arpa/nameser.h
> @@ -68,7 +68,6 @@ libresolv_hidden_proto (ns_parserr)
>  libresolv_hidden_proto (ns_sprintrr)
>  libresolv_hidden_proto (ns_sprintrrf)
>  libresolv_hidden_proto (ns_samedomain)
> -libresolv_hidden_proto (ns_samename)

OK.

>  libresolv_hidden_proto (ns_format_ttl)
>  
>  extern __typeof (ns_makecanon) __libc_ns_makecanon;
> @@ -87,6 +86,8 @@ extern __typeof (ns_name_uncompress) __ns_name_uncompress;
>  libc_hidden_proto (__ns_name_uncompress)
>  extern __typeof (ns_name_unpack) __ns_name_unpack;
>  libc_hidden_proto (__ns_name_unpack)
> +extern __typeof (ns_samename) __libc_ns_samename;
> +libc_hidden_proto (__libc_ns_samename)

OK.

>  
>  # endif /* !_ISOMAC */
>  #endif
> diff --git a/resolv/Makefile b/resolv/Makefile
> index d1ad5e4cba..744da951ae 100644
> --- a/resolv/Makefile
> +++ b/resolv/Makefile
> @@ -43,6 +43,7 @@ routines := \
>    ns_name_skip \
>    ns_name_uncompress \
>    ns_name_unpack \
> +  ns_samename \

OK.

>    nsap_addr \
>    res-close \
>    res-name-checking \
> diff --git a/resolv/Versions b/resolv/Versions
> index 93078de25c..2201d4224c 100644
> --- a/resolv/Versions
> +++ b/resolv/Versions
> @@ -73,6 +73,7 @@ libc {
>      __libc_dn_expand;
>      __libc_dn_skipname;
>      __libc_ns_makecanon;
> +    __libc_ns_samename;

OK.

>      __libc_res_dnok;
>      __libc_res_hnok;
>      __ns_name_compress;
> diff --git a/resolv/ns_print.c b/resolv/ns_print.c
> index 9a9602d74c..43f39edf61 100644
> --- a/resolv/ns_print.c
> +++ b/resolv/ns_print.c
> @@ -103,9 +103,9 @@ ns_sprintrrf(const u_char *msg, size_t msglen,
>  	/*
>  	 * Owner.
>  	 */
> -	if (name_ctx != NULL && ns_samename(name_ctx, name) == 1) {
> +	if (name_ctx != NULL && __libc_ns_samename (name_ctx, name) == 1)

OK.

>  		T(addstr("\t\t\t", 3, &buf, &buflen));
> -	} else {
> +	else {
>  		len = prune_origin(name, origin);
>  		if (*name == '\0') {
>  			goto root;
> @@ -621,7 +621,7 @@ prune_origin(const char *name, const char *origin) {
>  	const char *oname = name;
>  
>  	while (*name != '\0') {
> -		if (origin != NULL && ns_samename(name, origin) == 1)
> +		if (origin != NULL && __libc_ns_samename (name, origin) == 1)

OK.

>  			return (name - oname - (name > oname));
>  		while (*name != '\0') {
>  			if (*name == '\\') {
> diff --git a/resolv/ns_samedomain.c b/resolv/ns_samedomain.c
> index cfff2516b0..46cb8f5fb2 100644
> --- a/resolv/ns_samedomain.c
> +++ b/resolv/ns_samedomain.c
> @@ -139,31 +139,9 @@ libresolv_hidden_def (ns_samedomain)
>   *	is "a" a subdomain of "b"?
>   */
>  int
> -ns_subdomain(const char *a, const char *b) {
> -	return (ns_samename(a, b) != 1 && ns_samedomain(a, b));
> +ns_subdomain (const char *a, const char *b)
> +{
> +  return __libc_ns_samename (a, b) != 1 && ns_samedomain (a, b);

OK.

>  }
>  
> -/*%
> - *	determine whether domain name "a" is the same as domain name "b"
> - *
> - * return:
> - *\li	-1 on error
> - *\li	0 if names differ
> - *\li	1 if names are the same
> - */
> -
> -int
> -ns_samename(const char *a, const char *b) {
> -	char ta[NS_MAXDNAME], tb[NS_MAXDNAME];
> -
> -	if (__libc_ns_makecanon(a, ta, sizeof ta) < 0 ||
> -	    __libc_ns_makecanon(b, tb, sizeof tb) < 0)
> -		return (-1);
> -	if (strcasecmp(ta, tb) == 0)
> -		return (1);
> -	else
> -		return (0);
> -}
> -libresolv_hidden_def (ns_samename)

OK. Remove ns_samename.

> -
>  /*! \file */
> diff --git a/resolv/ns_samename.c b/resolv/ns_samename.c
> new file mode 100644
> index 0000000000..61fe3cab43
> --- /dev/null
> +++ b/resolv/ns_samename.c
> @@ -0,0 +1,38 @@
> +/* Check if two domain names are equal after trailing dot normalization.

OK.

> + * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
> + * Copyright (c) 1995,1999 by Internet Software Consortium.
> + *
> + * Permission to use, copy, modify, and distribute this software for any
> + * purpose with or without fee is hereby granted, provided that the above
> + * copyright notice and this permission notice appear in all copies.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
> + * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
> + * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
> + * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
> + * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
> + * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
> + * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
> + * SOFTWARE.
> + */
> +
> +#include <arpa/nameser.h>
> +#include <string.h>
> +
> +/* Determines whether domain name A is the same as domain name B.
> +   Returns -1 on error, 0 if names differ, 1 if names are the
> +   same.  */
> +int
> +__libc_ns_samename (const char *a, const char *b)
> +{
> +  char ta[NS_MAXDNAME], tb[NS_MAXDNAME];

OK.

> +
> +  if (__libc_ns_makecanon (a, ta, sizeof ta) < 0 ||
> +      __libc_ns_makecanon (b, tb, sizeof tb) < 0)
> +    return -1;
> +  if (__strcasecmp (ta, tb) == 0)
> +    return 1;
> +  else
> +    return 0;

OK. Match.

> +}
> +libc_hidden_def (__libc_ns_samename)
> diff --git a/resolv/res_query.c b/resolv/res_query.c
> index ebbe5a6a4e..5b51af8451 100644
> --- a/resolv/res_query.c
> +++ b/resolv/res_query.c
> @@ -656,7 +656,7 @@ __res_context_hostalias (struct resolv_context *ctx,
>  		if (!*cp1)
>  			break;
>  		*cp1 = '\0';
> -		if (ns_samename(buf, name) == 1) {
> +		if (__libc_ns_samename(buf, name) == 1) {

OK.

>  			while (isspace(*++cp1))
>  				;
>  			if (!*cp1)
> diff --git a/resolv/res_send.c b/resolv/res_send.c
> index 915fc6d2c6..dfea9fc7fa 100644
> --- a/resolv/res_send.c
> +++ b/resolv/res_send.c
> @@ -224,8 +224,8 @@ res_nameinquery(const char *name, int type, int class,
>  			return (-1);
>  		NS_GET16(ttype, cp);
>  		NS_GET16(tclass, cp);
> -		if (ttype == type && tclass == class &&
> -		    ns_samename(tname, name) == 1)
> +		if (ttype == type && tclass == class
> +		    && __libc_ns_samename (tname, name) == 1)

OK.

>  			return (1);
>  	}
>  	return (0);
> diff --git a/resolv/resolv-deprecated.c b/resolv/resolv-deprecated.c
> index cbd1078dc2..d8344f8f39 100644
> --- a/resolv/resolv-deprecated.c
> +++ b/resolv/resolv-deprecated.c
> @@ -33,3 +33,9 @@ ns_makecanon (const char *src, char *dst, size_t dstsize)
>  {
>    return __libc_ns_makecanon (src, dst, dstsize);
>  }
> +
> +int
> +ns_samename (const char *a, const char *b)
> +{
> +  return __libc_ns_samename (a, b);

OK. Forwarder.

> +}
> 


-- 
Cheers,
Carlos.