StdLib/BsdSocketLib/res_query.c - third_party/edk2 - Git at Google

 /*
  * Copyright (c) 1988, 1993
  *    The Regents of the University of California.  All rights reserved.
  *
  * Portions copyright (c) 1999, 2000
  * Intel Corporation.
  * 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.
  *
  * 3. All advertising materials mentioning features or use of this software
  *    must display the following acknowledgement:
  *
  *    This product includes software developed by the University of
  *    California, Berkeley, Intel Corporation, and its contributors.
  *
  * 4. Neither the name of University, Intel Corporation, or their respective
  *    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, INTEL CORPORATION 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,
  * INTEL CORPORATION 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 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 char sccsid[] = "@(#)res_query.c 8.1 (Berkeley) 6/4/93";
 static char orig_rcsid = "From: Id: res_query.c,v 8.14 1997/06/09 17:47:05 halley Exp $";
 static char rcsid[] = "$Id: res_query.c,v 1.1.1.1 2003/11/19 01:51:38 kyu3 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 "res_config.h"

 #if PACKETSZ > 1024
 #define MAXPACKET   PACKETSZ
 #else
 #define MAXPACKET   1024
 #endif

 /*
  * 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
 res_query(
     const char *name,   /* domain name */
     int class,          /* class of query */
     int type,           /* type of query */
     u_char *answer,     /* buffer to put answer */
     int anslen          /* size of answer buffer */
     )
 {
     u_char buf[MAXPACKET];
     HEADER *hp = (HEADER *) answer;
     int n;

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

     if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
         h_errno = NETDB_INTERNAL;
         return (-1);
     }
 #ifdef DEBUG
     if (_res.options & RES_DEBUG)
         printf(";; res_query(%s, %d, %d)\n", name, class, type);
 #endif

     n = res_mkquery(QUERY, name, class, type, NULL, 0, NULL,
             buf, sizeof(buf));
     if (n <= 0) {
 #ifdef DEBUG
         if (_res.options & RES_DEBUG)
             printf(";; res_query: mkquery failed\n");
 #endif
         h_errno = NO_RECOVERY;
         return (n);
     }
     n = res_send(buf, n, answer, anslen);
     if (n < 0) {
 #ifdef DEBUG
         if (_res.options & RES_DEBUG)
             printf(";; res_query: send error\n");
 #endif
         h_errno = TRY_AGAIN;
         return (n);
     }

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

 /*
  * 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
 res_search(
     const char *name,   /* domain name */
     int class,          /* class of query */
     int type,           /* type of query */
     u_char *answer,     /* buffer to put answer */
     int anslen          /* size of answer */
     )
 {
     const char *cp, * const *domain;
     HEADER *hp = (HEADER *) answer;
     u_int dots;
     int trailing_dot, ret, saved_herrno;
     int got_nodata = 0, got_servfail = 0, tried_as_is = 0;

     if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
         h_errno = NETDB_INTERNAL;
         return (-1);
     }
     errno = 0;
     h_errno = HOST_NOT_FOUND;   /* default, if we never query */
     dots = 0;
     for (cp = name; *cp; 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 = hostalias(name)) != NULL)
         return (res_query(cp, class, type, answer, anslen));

     /*
      * If there are dots in the name already, let's just give it a try
      * 'as is'.  The threshold can be set with the "ndots" option.
      */
     saved_herrno = -1;
     if (dots >= _res.ndots) {
         ret = res_querydomain(name, NULL, class, type, answer, anslen);
         if (ret > 0)
             return (ret);
         saved_herrno = h_errno;
         tried_as_is++;
     }

     /*
      * 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 && (_res.options & RES_DEFNAMES)) ||
         (dots && !trailing_dot && (_res.options & RES_DNSRCH))) {
         int done = 0;

         for (domain = (const char * const *)_res.dnsrch;
              *domain && !done;
              domain++) {

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

             /*
              * 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) {
                 h_errno = TRY_AGAIN;
                 return (-1);
             }

             switch (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 (!(_res.options & RES_DNSRCH))
                 done++;
         }
     }

     /*
      * If we have not already tried the name "as is", do that now.
      * note that we do this regardless of how many dots were in the
      * name or whether it ends with a dot unless NOTLDQUERY is set.
      */
     if (!tried_as_is && (dots || !(_res.options & RES_NOTLDQUERY))) {
         ret = res_querydomain(name, NULL, class, type, answer, anslen);
         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)
         h_errno = saved_herrno;
     else if (got_nodata)
         h_errno = NO_DATA;
     else if (got_servfail)
         h_errno = TRY_AGAIN;
     return (-1);
 }

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

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

 const char *
 hostalias(
     const char *name
     )
 {
     register char *cp1, *cp2;
     FILE *fp;
     char *file;
     char buf[BUFSIZ];
     static char abuf[MAXDNAME];

     if (_res.options & RES_NOALIASES)
         return (NULL);
 #ifdef _ORG_FREEBSD_
     if (issetugid())
         return (NULL);
 #endif
     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 (!strcasecmp(buf, name)) {
             while (isspace(*++cp1))
                 ;
             if (!*cp1)
                 break;
             for (cp2 = cp1 + 1; *cp2 && !isspace(*cp2); ++cp2)
                 ;
             abuf[sizeof(abuf) - 1] = *cp2 = '\0';
             strncpy(abuf, cp1, sizeof(abuf) - 1);
             fclose(fp);
             return (abuf);
         }
     }
     fclose(fp);
     return (NULL);
 }
	/*
	* Copyright (c) 1988, 1993
	* The Regents of the University of California. All rights reserved.
	*
	* Portions copyright (c) 1999, 2000
	* Intel Corporation.
	* 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.
	*
	* 3. All advertising materials mentioning features or use of this software
	* must display the following acknowledgement:
	*
	* This product includes software developed by the University of
	* California, Berkeley, Intel Corporation, and its contributors.
	*
	* 4. Neither the name of University, Intel Corporation, or their respective
	* 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, INTEL CORPORATION 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,
	* INTEL CORPORATION 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 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 char sccsid[] = "@(#)res_query.c 8.1 (Berkeley) 6/4/93";
	static char orig_rcsid = "From: Id: res_query.c,v 8.14 1997/06/09 17:47:05 halley Exp $";
	static char rcsid[] = "$Id: res_query.c,v 1.1.1.1 2003/11/19 01:51:38 kyu3 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 "res_config.h"

	#if PACKETSZ > 1024
	#define MAXPACKET PACKETSZ
	#else
	#define MAXPACKET 1024
	#endif

	/*
	* 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
	res_query(
	const char name, / domain name */
	int class, /* class of query */
	int type, /* type of query */
	u_char answer, / buffer to put answer */
	int anslen /* size of answer buffer */
	)
	{
	u_char buf[MAXPACKET];
	HEADER hp = (HEADER ) answer;
	int n;

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

	if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
	h_errno = NETDB_INTERNAL;
	return (-1);
	}
	#ifdef DEBUG
	if (_res.options & RES_DEBUG)
	printf(";; res_query(%s, %d, %d)\n", name, class, type);
	#endif

	n = res_mkquery(QUERY, name, class, type, NULL, 0, NULL,
	buf, sizeof(buf));
	if (n <= 0) {
	#ifdef DEBUG
	if (_res.options & RES_DEBUG)
	printf(";; res_query: mkquery failed\n");
	#endif
	h_errno = NO_RECOVERY;
	return (n);
	}
	n = res_send(buf, n, answer, anslen);
	if (n < 0) {
	#ifdef DEBUG
	if (_res.options & RES_DEBUG)
	printf(";; res_query: send error\n");
	#endif
	h_errno = TRY_AGAIN;
	return (n);
	}

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

	/*
	* 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
	res_search(
	const char name, / domain name */
	int class, /* class of query */
	int type, /* type of query */
	u_char answer, / buffer to put answer */
	int anslen /* size of answer */
	)
	{
	const char cp, const *domain;
	HEADER hp = (HEADER ) answer;
	u_int dots;
	int trailing_dot, ret, saved_herrno;
	int got_nodata = 0, got_servfail = 0, tried_as_is = 0;

	if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
	h_errno = NETDB_INTERNAL;
	return (-1);
	}
	errno = 0;
	h_errno = HOST_NOT_FOUND; /* default, if we never query */
	dots = 0;
	for (cp = name; *cp; 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 = hostalias(name)) != NULL)
	return (res_query(cp, class, type, answer, anslen));

	/*
	* If there are dots in the name already, let's just give it a try
	* 'as is'. The threshold can be set with the "ndots" option.
	*/
	saved_herrno = -1;
	if (dots >= _res.ndots) {
	ret = res_querydomain(name, NULL, class, type, answer, anslen);
	if (ret > 0)
	return (ret);
	saved_herrno = h_errno;
	tried_as_is++;
	}

	/*
	* 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 && (_res.options & RES_DEFNAMES)) \|\|
	(dots && !trailing_dot && (_res.options & RES_DNSRCH))) {
	int done = 0;

	for (domain = (const char * const *)_res.dnsrch;
	*domain && !done;
	domain++) {

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

	/*
	* 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) {
	h_errno = TRY_AGAIN;
	return (-1);
	}

	switch (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 (!(_res.options & RES_DNSRCH))
	done++;
	}
	}

	/*
	* If we have not already tried the name "as is", do that now.
	* note that we do this regardless of how many dots were in the
	* name or whether it ends with a dot unless NOTLDQUERY is set.
	*/
	if (!tried_as_is && (dots \|\| !(_res.options & RES_NOTLDQUERY))) {
	ret = res_querydomain(name, NULL, class, type, answer, anslen);
	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)
	h_errno = saved_herrno;
	else if (got_nodata)
	h_errno = NO_DATA;
	else if (got_servfail)
	h_errno = TRY_AGAIN;
	return (-1);
	}

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

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

	const char *
	hostalias(
	const char *name
	)
	{
	register char cp1, cp2;
	FILE *fp;
	char *file;
	char buf[BUFSIZ];
	static char abuf[MAXDNAME];

	if (_res.options & RES_NOALIASES)
	return (NULL);
	#ifdef _ORG_FREEBSD_
	if (issetugid())
	return (NULL);
	#endif
	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 (!strcasecmp(buf, name)) {
	while (isspace(*++cp1))
	;
	if (!*cp1)
	break;
	for (cp2 = cp1 + 1; cp2 && !isspace(cp2); ++cp2)
	;
	abuf[sizeof(abuf) - 1] = *cp2 = '\0';
	strncpy(abuf, cp1, sizeof(abuf) - 1);
	fclose(fp);
	return (abuf);
	}
	}
	fclose(fp);
	return (NULL);
	}