patch for res_nsearch()

[G Muthukumar]

This patch reverts the res_nsearch() behaviour to that of res_search() (of
the earlier (4.9.x & pre 8.2.x) versions), when the 'as is' query for a name
(with a dot in it) has failed. 

	Most of this patch code comes from the older version; checks for 
trailing_dot & root_on_list and few comment lines are new.

Paul:
	If you feel this patch can be included in 8.2.3, then please do so.


*** res_query.c	Fri Feb  4 14:28:25 2000
--- res_query.c	Fri Feb  4 15:03:28 2000
***************
*** 190,197 ****
  	HEADER *hp = (HEADER *) answer;
  	char tmp[NS_MAXDNAME];
  	u_int dots;
! 	int trailing_dot, ret;
  	int got_nodata = 0, got_servfail = 0, root_on_list = 0;
  
  	errno = 0;
  	RES_SET_H_ERRNO(statp, HOST_NOT_FOUND);  /* True if we never query. */
--- 190,198 ----
  	HEADER *hp = (HEADER *) answer;
  	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 tried_as_is = 0;
  
  	errno = 0;
  	RES_SET_H_ERRNO(statp, HOST_NOT_FOUND);  /* True if we never query. */
***************
*** 208,219 ****
  		return (res_nquery(statp, cp, class, type, answer, anslen));
  
  	/*
! 	 * If there are enough dots in the name, do no searching.
! 	 * (The threshold can be set with the "ndots" option.)
  	 */
! 	if (dots >= statp->ndots || trailing_dot)
! 		return (res_nquerydomain(statp, name, NULL, class, type,
! 					 answer, anslen));
  
  	/*
  	 * We do at least one level of search if
--- 209,227 ----
  		return (res_nquery(statp, cp, class, type, answer, anslen));
  
  	/*
! 	 * If there are enough dots in the name, let's just give it a
! 	 * try 'as is'. The threshold can be set with the "ndots" option.
! 	 * Also, query 'as is', if there is a trailing dot in the name.
  	 */
! 	saved_herrno = -1;
! 	if (dots >= statp->ndots || trailing_dot) {
! 		ret = res_nquerydomain(statp, name, NULL, class, type,
! 					 answer, anslen);
! 		if (ret > 0 || trailing_dot)
! 			return (ret);
! 		saved_herrno = h_errno;
! 		tried_as_is++;
! 	}
  
  	/*
  	 * We do at least one level of search if
***************
*** 285,294 ****
  	}
  
  	/*
! 	 * If the name has any dots at all, and "." is not on the search
! 	 * list, then try an as-is query now.
  	 */
! 	if (statp->ndots) {
  		ret = res_nquerydomain(statp, name, NULL, class, type,
  				       answer, anslen);
  		if (ret > 0)
--- 293,303 ----
  	}
  
  	/*
! 	 * If the name has any dots at all, and no earlier 'as-is' query 
! 	 * for the name, and "." is not on the search list, then try an as-is
! 	 * query now.
  	 */
! 	if (statp->ndots && !(tried_as_is || root_on_list)) {
  		ret = res_nquerydomain(statp, name, NULL, class, type,
  				       answer, anslen);
  		if (ret > 0)
***************
*** 302,308 ****
  	 * else send back meaningless H_ERRNO, that being the one from
  	 * the last DNSRCH we did.
  	 */
! 	if (got_nodata)
  		RES_SET_H_ERRNO(statp, NO_DATA);
  	else if (got_servfail)
  		RES_SET_H_ERRNO(statp, TRY_AGAIN);
--- 311,319 ----
  	 * else send back meaningless H_ERRNO, that being the one from
  	 * the last DNSRCH we did.
  	 */
! 	if (saved_herrno != -1)
! 		RES_SET_H_ERRNO(statp, saved_herrno);
! 	else if (got_nodata)
  		RES_SET_H_ERRNO(statp, NO_DATA);
  	else if (got_servfail)
  		RES_SET_H_ERRNO(statp, TRY_AGAIN);