ports/glibc-compat/src/res_query.c - external/naclports - Git at Google

 /*
  * Copyright (c) 1988, 1993
  *    The Regents of the University of California.  All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  * 4. Neither the name of the University nor the names of its contributors
  *    may be used to endorse or promote products derived from this software
  *    without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  */

 /*
  * Portions Copyright (c) 1993 by Digital Equipment Corporation.
  *
  * 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, and that
  * the name of Digital Equipment Corporation not be used in advertising or
  * publicity pertaining to distribution of the document or software without
  * specific, written prior permission.
  *
  * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
  * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
  * OF MERCHANTABILITY AND FITNESS.   IN NO EVENT SHALL DIGITAL EQUIPMENT
  * CORPORATION 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.
  */

 /*
  * Portions Copyright (c) 1996-1999 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.
  */

 #if defined(LIBC_SCCS) && !defined(lint)
 static const char sccsid[] = "@(#)res_query.c	8.1 (Berkeley) 6/4/93";
 static const char rcsid[] = "$BINDId: res_query.c,v 8.20 2000/02/29 05:39:12 vixie Exp $";
 #endif /* LIBC_SCCS and not lint */

 #include <sys/types.h>
 #include <sys/param.h>
 #include <netinet/in.h>
 #include <arpa/inet.h>
 #include <arpa/nameser.h>
 #include <ctype.h>
 #include <errno.h>
 #include <netdb.h>
 #include <resolv.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include "libc-symbols.h"

 /* Options.  Leave them on. */
 /* #undef DEBUG */

 #if PACKETSZ > 65536
 #define MAXPACKET	PACKETSZ
 #else
 #define MAXPACKET	65536
 #endif

 #define QUERYSIZE	(HFIXEDSZ + QFIXEDSZ + MAXCDNAME + 1)

 static int
 __libc_res_nquerydomain(res_state statp, const char *name, const char *domain,
 			int class, int type, u_char *answer, int anslen,
 			u_char **answerp);

 /*
  * Formulate a normal query, send, and await answer.
  * Returned answer is placed in supplied buffer "answer".
  * Perform preliminary check of answer, returning success only
  * if no error is indicated and the answer count is nonzero.
  * Return the size of the response on success, -1 on error.
  * Error number is left in H_ERRNO.
  *
  * Caller must parse answer and determine whether it answers the question.
  */
 int
 __libc_res_nquery(res_state statp,
 		  const char *name,	/* domain name */
 		  int class, int type,	/* class and type of query */
 		  u_char *answer,	/* buffer to put answer */
 		  int anslen,		/* size of answer buffer */
 		  u_char **answerp)	/* if buffer needs to be enlarged */
 {
 	u_char *buf;
 	HEADER *hp = (HEADER *) answer;
 	int n, use_malloc = 0;

 	hp->rcode = NOERROR;	/* default */

 	buf = alloca (QUERYSIZE);

 #ifdef DEBUG
 	if (statp->options & RES_DEBUG)
 		printf(";; res_query(%s, %d, %d)\n", name, class, type);
 #endif

 	n = res_nmkquery(statp, QUERY, name, class, type, NULL, 0, NULL,
 			 buf, QUERYSIZE);
 	if (__builtin_expect (n <= 0, 0)) {
 		/* Retry just in case res_nmkquery failed because of too
 		   short buffer.  Shouldn't happen.  */
 		buf = malloc (MAXPACKET);
 		if (buf != NULL) {
 			use_malloc = 1;
 			n = res_nmkquery(statp, QUERY, name, class, type, NULL,
 					 0, NULL, buf, MAXPACKET);
 		}
 	}
 	if (__builtin_expect (n <= 0, 0)) {
 #ifdef DEBUG
 		if (statp->options & RES_DEBUG)
 			printf(";; res_query: mkquery failed\n");
 #endif
 		RES_SET_H_ERRNO(statp, NO_RECOVERY);
 		if (use_malloc)
 			free (buf);
 		return (n);
 	}
 	n = __libc_res_nsend(statp, buf, n, answer, anslen, answerp);
 	if (use_malloc)
 		free (buf);
 	if (n < 0) {
 #ifdef DEBUG
 		if (statp->options & RES_DEBUG)
 			printf(";; res_query: send error\n");
 #endif
 		RES_SET_H_ERRNO(statp, TRY_AGAIN);
 		return (n);
 	}

 	if (hp->rcode != NOERROR || ntohs(hp->ancount) == 0) {
 #ifdef DEBUG
 		if (statp->options & RES_DEBUG)
 			printf(";; rcode = %d, ancount=%d\n", hp->rcode,
 			    ntohs(hp->ancount));
 #endif
 		switch (hp->rcode) {
 		case NXDOMAIN:
 			RES_SET_H_ERRNO(statp, HOST_NOT_FOUND);
 			break;
 		case SERVFAIL:
 			RES_SET_H_ERRNO(statp, TRY_AGAIN);
 			break;
 		case NOERROR:
 			RES_SET_H_ERRNO(statp, NO_DATA);
 			break;
 		case FORMERR:
 		case NOTIMP:
 		case REFUSED:
 		default:
 			RES_SET_H_ERRNO(statp, NO_RECOVERY);
 			break;
 		}
 		return (-1);
 	}
 	return (n);
 }
 libresolv_hidden_def (__libc_res_nquery)

 int
 res_nquery(res_state statp,
 	   const char *name,	/* domain name */
 	   int class, int type,	/* class and type of query */
 	   u_char *answer,	/* buffer to put answer */
 	   int anslen)		/* size of answer buffer */
 {
 	return __libc_res_nquery(statp, name, class, type, answer, anslen,
 				 NULL);
 }
 libresolv_hidden_def (res_nquery)

 /*
  * Formulate a normal query, send, and retrieve answer in supplied buffer.
  * Return the size of the response on success, -1 on error.
  * If enabled, implement search rules until answer or unrecoverable failure
  * is detected.  Error code, if any, is left in H_ERRNO.
  */
 int
 __libc_res_nsearch(res_state statp,
 	    const char *name,	/* domain name */
 	    int class, int type,	/* class and type of query */
 	    u_char *answer,	/* buffer to put answer */
 	    int anslen,		/* size of answer */
 	    u_char **answerp)
 {
 	const char *cp, * const *domain;
 	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;

 	__set_errno (0);
 	RES_SET_H_ERRNO(statp, HOST_NOT_FOUND);  /* True if we never query. */

 	dots = 0;
 	for (cp = name; *cp != '\0'; cp++)
 		dots += (*cp == '.');
 	trailing_dot = 0;
 	if (cp > name && *--cp == '.')
 		trailing_dot++;

 	/* If there aren't any dots, it could be a user-level alias. */
 	if (!dots && (cp = res_hostalias(statp, name, tmp, sizeof tmp))!= NULL)
 		return (__libc_res_nquery(statp, cp, class, type, answer,
 					  anslen, answerp));

 #ifdef DEBUG
 	if (statp->options & RES_DEBUG)
 		printf("dots=%d, statp->ndots=%d, trailing_dot=%d, name=%s\n",
 		       (int)dots,(int)statp->ndots,(int)trailing_dot,name);
 #endif

 	/*
 	 * 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 = __libc_res_nquerydomain(statp, name, NULL, class, type,
 					      answer, anslen, answerp);
 		if (ret > 0 || trailing_dot)
 			return (ret);
 		saved_herrno = h_errno;
 		tried_as_is++;
 		if (answerp && *answerp != answer) {
 			answer = *answerp;
 			anslen = MAXPACKET;
 		}
 	}

 	/*
 	 * We do at least one level of search if
 	 *	- there is no dot and RES_DEFNAME is set, or
 	 *	- there is at least one dot, there is no trailing dot,
 	 *	  and RES_DNSRCH is set.
 	 */
 	if ((!dots && (statp->options & RES_DEFNAMES) != 0) ||
 	    (dots && !trailing_dot && (statp->options & RES_DNSRCH) != 0)) {
 		int done = 0;

 		for (domain = (const char * const *)statp->dnsrch;
 		     *domain && !done;
 		     domain++) {

 			if (domain[0][0] == '\0' ||
 			    (domain[0][0] == '.' && domain[0][1] == '\0'))
 				root_on_list++;

 			ret = __libc_res_nquerydomain(statp, name, *domain,
 						      class, type,
 						      answer, anslen, answerp);
 			if (ret > 0)
 				return (ret);

 			if (answerp && *answerp != answer) {
 				answer = *answerp;
 				anslen = MAXPACKET;
 			}

 			/*
 			 * If no server present, give up.
 			 * If name isn't found in this domain,
 			 * keep trying higher domains in the search list
 			 * (if that's enabled).
 			 * On a NO_DATA error, keep trying, otherwise
 			 * a wildcard entry of another type could keep us
 			 * from finding this entry higher in the domain.
 			 * If we get some other error (negative answer or
 			 * server failure), then stop searching up,
 			 * but try the input name below in case it's
 			 * fully-qualified.
 			 */
 			if (errno == ECONNREFUSED) {
 				RES_SET_H_ERRNO(statp, TRY_AGAIN);
 				return (-1);
 			}

 			switch (statp->res_h_errno) {
 			case NO_DATA:
 				got_nodata++;
 				/* FALLTHROUGH */
 			case HOST_NOT_FOUND:
 				/* keep trying */
 				break;
 			case TRY_AGAIN:
 				if (hp->rcode == SERVFAIL) {
 					/* try next search element, if any */
 					got_servfail++;
 					break;
 				}
 				/* FALLTHROUGH */
 			default:
 				/* anything else implies that we're done */
 				done++;
 			}

 			/* if we got here for some reason other than DNSRCH,
 			 * we only wanted one iteration of the loop, so stop.
 			 */
 			if ((statp->options & RES_DNSRCH) == 0)
 				done++;
 		}
 	}

 	/*
 	 * 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 (dots && !(tried_as_is || root_on_list)) {
 		ret = __libc_res_nquerydomain(statp, name, NULL, class, type,
 					      answer, anslen, answerp);
 		if (ret > 0)
 			return (ret);
 	}

 	/* if we got here, we didn't satisfy the search.
 	 * if we did an initial full query, return that query's H_ERRNO
 	 * (note that we wouldn't be here if that query had succeeded).
 	 * else if we ever got a nodata, send that back as the reason.
 	 * 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);
 	return (-1);
 }
 libresolv_hidden_def (__libc_res_nsearch)

 int
 res_nsearch(res_state statp,
 	    const char *name,	/* domain name */
 	    int class, int type,	/* class and type of query */
 	    u_char *answer,	/* buffer to put answer */
 	    int anslen)		/* size of answer */
 {
 	return __libc_res_nsearch(statp, name, class, type, answer,
 				  anslen, NULL);
 }
 libresolv_hidden_def (res_nsearch)

 /*
  * Perform a call on res_query on the concatenation of name and domain,
  * removing a trailing dot from name if domain is NULL.
  */
 static int
 __libc_res_nquerydomain(res_state statp,
 	    const char *name,
 	    const char *domain,
 	    int class, int type,	/* class and type of query */
 	    u_char *answer,		/* buffer to put answer */
 	    int anslen,			/* size of answer */
 	    u_char **answerp)
 {
 	char nbuf[MAXDNAME];
 	const char *longname = nbuf;
 	int n, d;

 #ifdef DEBUG
 	if (statp->options & RES_DEBUG)
 		printf(";; res_nquerydomain(%s, %s, %d, %d)\n",
 		       name, domain?domain:"<Nil>", class, type);
 #endif
 	if (domain == NULL) {
 		/*
 		 * Check for trailing '.';
 		 * copy without '.' if present.
 		 */
 		n = strlen(name);
 		if (n >= MAXDNAME) {
 			RES_SET_H_ERRNO(statp, NO_RECOVERY);
 			return (-1);
 		}
 		n--;
 		if (n >= 0 && name[n] == '.') {
 			strncpy(nbuf, name, n);
 			nbuf[n] = '\0';
 		} else
 			longname = name;
 	} else {
 		n = strlen(name);
 		d = strlen(domain);
 		if (n + d + 1 >= MAXDNAME) {
 			RES_SET_H_ERRNO(statp, NO_RECOVERY);
 			return (-1);
 		}
 		sprintf(nbuf, "%s.%s", name, domain);
 	}
 	return (__libc_res_nquery(statp, longname, class, type, answer,
 				  anslen, answerp));
 }

 int
 res_nquerydomain(res_state statp,
 	    const char *name,
 	    const char *domain,
 	    int class, int type,	/* class and type of query */
 	    u_char *answer,		/* buffer to put answer */
 	    int anslen)		/* size of answer */
 {
 	return __libc_res_nquerydomain(statp, name, domain, class, type,
 				       answer, anslen, NULL);
 }
 libresolv_hidden_def (res_nquerydomain)

 const char *
 res_hostalias(const res_state statp, const char *name, char *dst, size_t siz) {
 	char *file, *cp1, *cp2;
 	char buf[BUFSIZ];
 	FILE *fp;

 	if (statp->options & RES_NOALIASES)
 		return (NULL);
 	file = getenv("HOSTALIASES");
 	if (file == NULL || (fp = fopen(file, "r")) == NULL)
 		return (NULL);
 	setbuf(fp, NULL);
 	buf[sizeof(buf) - 1] = '\0';
 	while (fgets(buf, sizeof(buf), fp)) {
 		for (cp1 = buf; *cp1 && !isspace(*cp1); ++cp1)
 			;
 		if (!*cp1)
 			break;
 		*cp1 = '\0';
 		if (ns_samename(buf, name) == 1) {
 			while (isspace(*++cp1))
 				;
 			if (!*cp1)
 				break;
 			for (cp2 = cp1 + 1; *cp2 && !isspace(*cp2); ++cp2)
 				;
 			*cp2 = '\0';
 			strncpy(dst, cp1, siz - 1);
 			dst[siz - 1] = '\0';
 			fclose(fp);
 			return (dst);
 		}
 	}
 	fclose(fp);
 	return (NULL);
 }
 libresolv_hidden_def (res_hostalias)
	/*
	* Copyright (c) 1988, 1993
	* The Regents of the University of California. All rights reserved.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions
	* are met:
	* 1. Redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer.
	* 2. Redistributions in binary form must reproduce the above copyright
	* notice, this list of conditions and the following disclaimer in the
	* documentation and/or other materials provided with the distribution.
	* 4. Neither the name of the University nor the names of its contributors
	* may be used to endorse or promote products derived from this software
	* without specific prior written permission.
	*
	* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	* SUCH DAMAGE.
	*/

	/*
	* Portions Copyright (c) 1993 by Digital Equipment Corporation.
	*
	* 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, and that
	* the name of Digital Equipment Corporation not be used in advertising or
	* publicity pertaining to distribution of the document or software without
	* specific, written prior permission.
	*
	* THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
	* WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
	* OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL DIGITAL EQUIPMENT
	* CORPORATION 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.
	*/

	/*
	* Portions Copyright (c) 1996-1999 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.
	*/

	#if defined(LIBC_SCCS) && !defined(lint)
	static const char sccsid[] = "@(#)res_query.c 8.1 (Berkeley) 6/4/93";
	static const char rcsid[] = "$BINDId: res_query.c,v 8.20 2000/02/29 05:39:12 vixie Exp $";
	#endif /* LIBC_SCCS and not lint */

	#include <sys/types.h>
	#include <sys/param.h>
	#include <netinet/in.h>
	#include <arpa/inet.h>
	#include <arpa/nameser.h>
	#include <ctype.h>
	#include <errno.h>
	#include <netdb.h>
	#include <resolv.h>
	#include <stdio.h>
	#include <stdlib.h>
	#include <string.h>
	#include "libc-symbols.h"

	/* Options. Leave them on. */
	/* #undef DEBUG */

	#if PACKETSZ > 65536
	#define MAXPACKET PACKETSZ
	#else
	#define MAXPACKET 65536
	#endif

	#define QUERYSIZE (HFIXEDSZ + QFIXEDSZ + MAXCDNAME + 1)

	static int
	__libc_res_nquerydomain(res_state statp, const char name, const char domain,
	int class, int type, u_char *answer, int anslen,
	u_char **answerp);

	/*
	* Formulate a normal query, send, and await answer.
	* Returned answer is placed in supplied buffer "answer".
	* Perform preliminary check of answer, returning success only
	* if no error is indicated and the answer count is nonzero.
	* Return the size of the response on success, -1 on error.
	* Error number is left in H_ERRNO.
	*
	* Caller must parse answer and determine whether it answers the question.
	*/
	int
	__libc_res_nquery(res_state statp,
	const char name, / domain name */
	int class, int type, /* class and type of query */
	u_char answer, / buffer to put answer */
	int anslen, /* size of answer buffer */
	u_char *answerp) / if buffer needs to be enlarged */
	{
	u_char *buf;
	HEADER hp = (HEADER ) answer;
	int n, use_malloc = 0;

	hp->rcode = NOERROR; /* default */

	buf = alloca (QUERYSIZE);

	#ifdef DEBUG
	if (statp->options & RES_DEBUG)
	printf(";; res_query(%s, %d, %d)\n", name, class, type);
	#endif

	n = res_nmkquery(statp, QUERY, name, class, type, NULL, 0, NULL,
	buf, QUERYSIZE);
	if (__builtin_expect (n <= 0, 0)) {
	/* Retry just in case res_nmkquery failed because of too
	short buffer. Shouldn't happen. */
	buf = malloc (MAXPACKET);
	if (buf != NULL) {
	use_malloc = 1;
	n = res_nmkquery(statp, QUERY, name, class, type, NULL,
	0, NULL, buf, MAXPACKET);
	}
	}
	if (__builtin_expect (n <= 0, 0)) {
	#ifdef DEBUG
	if (statp->options & RES_DEBUG)
	printf(";; res_query: mkquery failed\n");
	#endif
	RES_SET_H_ERRNO(statp, NO_RECOVERY);
	if (use_malloc)
	free (buf);
	return (n);
	}
	n = __libc_res_nsend(statp, buf, n, answer, anslen, answerp);
	if (use_malloc)
	free (buf);
	if (n < 0) {
	#ifdef DEBUG
	if (statp->options & RES_DEBUG)
	printf(";; res_query: send error\n");
	#endif
	RES_SET_H_ERRNO(statp, TRY_AGAIN);
	return (n);
	}

	if (hp->rcode != NOERROR \|\| ntohs(hp->ancount) == 0) {
	#ifdef DEBUG
	if (statp->options & RES_DEBUG)
	printf(";; rcode = %d, ancount=%d\n", hp->rcode,
	ntohs(hp->ancount));
	#endif
	switch (hp->rcode) {
	case NXDOMAIN:
	RES_SET_H_ERRNO(statp, HOST_NOT_FOUND);
	break;
	case SERVFAIL:
	RES_SET_H_ERRNO(statp, TRY_AGAIN);
	break;
	case NOERROR:
	RES_SET_H_ERRNO(statp, NO_DATA);
	break;
	case FORMERR:
	case NOTIMP:
	case REFUSED:
	default:
	RES_SET_H_ERRNO(statp, NO_RECOVERY);
	break;
	}
	return (-1);
	}
	return (n);
	}
	libresolv_hidden_def (__libc_res_nquery)

	int
	res_nquery(res_state statp,
	const char name, / domain name */
	int class, int type, /* class and type of query */
	u_char answer, / buffer to put answer */
	int anslen) /* size of answer buffer */
	{
	return __libc_res_nquery(statp, name, class, type, answer, anslen,
	NULL);
	}
	libresolv_hidden_def (res_nquery)

	/*
	* Formulate a normal query, send, and retrieve answer in supplied buffer.
	* Return the size of the response on success, -1 on error.
	* If enabled, implement search rules until answer or unrecoverable failure
	* is detected. Error code, if any, is left in H_ERRNO.
	*/
	int
	__libc_res_nsearch(res_state statp,
	const char name, / domain name */
	int class, int type, /* class and type of query */
	u_char answer, / buffer to put answer */
	int anslen, /* size of answer */
	u_char **answerp)
	{
	const char cp, const *domain;
	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;

	__set_errno (0);
	RES_SET_H_ERRNO(statp, HOST_NOT_FOUND); /* True if we never query. */

	dots = 0;
	for (cp = name; *cp != '\0'; cp++)
	dots += (*cp == '.');
	trailing_dot = 0;
	if (cp > name && *--cp == '.')
	trailing_dot++;

	/* If there aren't any dots, it could be a user-level alias. */
	if (!dots && (cp = res_hostalias(statp, name, tmp, sizeof tmp))!= NULL)
	return (__libc_res_nquery(statp, cp, class, type, answer,
	anslen, answerp));

	#ifdef DEBUG
	if (statp->options & RES_DEBUG)
	printf("dots=%d, statp->ndots=%d, trailing_dot=%d, name=%s\n",
	(int)dots,(int)statp->ndots,(int)trailing_dot,name);
	#endif

	/*
	* 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 = __libc_res_nquerydomain(statp, name, NULL, class, type,
	answer, anslen, answerp);
	if (ret > 0 \|\| trailing_dot)
	return (ret);
	saved_herrno = h_errno;
	tried_as_is++;
	if (answerp && *answerp != answer) {
	answer = *answerp;
	anslen = MAXPACKET;
	}
	}

	/*
	* We do at least one level of search if
	* - there is no dot and RES_DEFNAME is set, or
	* - there is at least one dot, there is no trailing dot,
	* and RES_DNSRCH is set.
	*/
	if ((!dots && (statp->options & RES_DEFNAMES) != 0) \|\|
	(dots && !trailing_dot && (statp->options & RES_DNSRCH) != 0)) {
	int done = 0;

	for (domain = (const char * const *)statp->dnsrch;
	*domain && !done;
	domain++) {

	if (domain[0][0] == '\0' \|\|
	(domain[0][0] == '.' && domain[0][1] == '\0'))
	root_on_list++;

	ret = __libc_res_nquerydomain(statp, name, *domain,
	class, type,
	answer, anslen, answerp);
	if (ret > 0)
	return (ret);

	if (answerp && *answerp != answer) {
	answer = *answerp;
	anslen = MAXPACKET;
	}

	/*
	* If no server present, give up.
	* If name isn't found in this domain,
	* keep trying higher domains in the search list
	* (if that's enabled).
	* On a NO_DATA error, keep trying, otherwise
	* a wildcard entry of another type could keep us
	* from finding this entry higher in the domain.
	* If we get some other error (negative answer or
	* server failure), then stop searching up,
	* but try the input name below in case it's
	* fully-qualified.
	*/
	if (errno == ECONNREFUSED) {
	RES_SET_H_ERRNO(statp, TRY_AGAIN);
	return (-1);
	}

	switch (statp->res_h_errno) {
	case NO_DATA:
	got_nodata++;
	/* FALLTHROUGH */
	case HOST_NOT_FOUND:
	/* keep trying */
	break;
	case TRY_AGAIN:
	if (hp->rcode == SERVFAIL) {
	/* try next search element, if any */
	got_servfail++;
	break;
	}
	/* FALLTHROUGH */
	default:
	/* anything else implies that we're done */
	done++;
	}

	/* if we got here for some reason other than DNSRCH,
	* we only wanted one iteration of the loop, so stop.
	*/
	if ((statp->options & RES_DNSRCH) == 0)
	done++;
	}
	}

	/*
	* 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 (dots && !(tried_as_is \|\| root_on_list)) {
	ret = __libc_res_nquerydomain(statp, name, NULL, class, type,
	answer, anslen, answerp);
	if (ret > 0)
	return (ret);
	}

	/* if we got here, we didn't satisfy the search.
	* if we did an initial full query, return that query's H_ERRNO
	* (note that we wouldn't be here if that query had succeeded).
	* else if we ever got a nodata, send that back as the reason.
	* 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);
	return (-1);
	}
	libresolv_hidden_def (__libc_res_nsearch)

	int
	res_nsearch(res_state statp,
	const char name, / domain name */
	int class, int type, /* class and type of query */
	u_char answer, / buffer to put answer */
	int anslen) /* size of answer */
	{
	return __libc_res_nsearch(statp, name, class, type, answer,
	anslen, NULL);
	}
	libresolv_hidden_def (res_nsearch)

	/*
	* Perform a call on res_query on the concatenation of name and domain,
	* removing a trailing dot from name if domain is NULL.
	*/
	static int
	__libc_res_nquerydomain(res_state statp,
	const char *name,
	const char *domain,
	int class, int type, /* class and type of query */
	u_char answer, / buffer to put answer */
	int anslen, /* size of answer */
	u_char **answerp)
	{
	char nbuf[MAXDNAME];
	const char *longname = nbuf;
	int n, d;

	#ifdef DEBUG
	if (statp->options & RES_DEBUG)
	printf(";; res_nquerydomain(%s, %s, %d, %d)\n",
	name, domain?domain:"<Nil>", class, type);
	#endif
	if (domain == NULL) {
	/*
	* Check for trailing '.';
	* copy without '.' if present.
	*/
	n = strlen(name);
	if (n >= MAXDNAME) {
	RES_SET_H_ERRNO(statp, NO_RECOVERY);
	return (-1);
	}
	n--;
	if (n >= 0 && name[n] == '.') {
	strncpy(nbuf, name, n);
	nbuf[n] = '\0';
	} else
	longname = name;
	} else {
	n = strlen(name);
	d = strlen(domain);
	if (n + d + 1 >= MAXDNAME) {
	RES_SET_H_ERRNO(statp, NO_RECOVERY);
	return (-1);
	}
	sprintf(nbuf, "%s.%s", name, domain);
	}
	return (__libc_res_nquery(statp, longname, class, type, answer,
	anslen, answerp));
	}

	int
	res_nquerydomain(res_state statp,
	const char *name,
	const char *domain,
	int class, int type, /* class and type of query */
	u_char answer, / buffer to put answer */
	int anslen) /* size of answer */
	{
	return __libc_res_nquerydomain(statp, name, domain, class, type,
	answer, anslen, NULL);
	}
	libresolv_hidden_def (res_nquerydomain)

	const char *
	res_hostalias(const res_state statp, const char name, char dst, size_t siz) {
	char file, cp1, *cp2;
	char buf[BUFSIZ];
	FILE *fp;

	if (statp->options & RES_NOALIASES)
	return (NULL);
	file = getenv("HOSTALIASES");
	if (file == NULL \|\| (fp = fopen(file, "r")) == NULL)
	return (NULL);
	setbuf(fp, NULL);
	buf[sizeof(buf) - 1] = '\0';
	while (fgets(buf, sizeof(buf), fp)) {
	for (cp1 = buf; cp1 && !isspace(cp1); ++cp1)
	;
	if (!*cp1)
	break;
	*cp1 = '\0';
	if (ns_samename(buf, name) == 1) {
	while (isspace(*++cp1))
	;
	if (!*cp1)
	break;
	for (cp2 = cp1 + 1; cp2 && !isspace(cp2); ++cp2)
	;
	*cp2 = '\0';
	strncpy(dst, cp1, siz - 1);
	dst[siz - 1] = '\0';
	fclose(fp);
	return (dst);
	}
	}
	fclose(fp);
	return (NULL);
	}
	libresolv_hidden_def (res_hostalias)