xref: /netbsd-src/lib/libc/net/gethnamaddr.c (revision a4ddc2c8fb9af816efe3b1c375a5530aef0e89e9)
1 /*	$NetBSD: gethnamaddr.c,v 1.79 2012/09/09 16:42:23 christos Exp $	*/
2 
3 /*
4  * ++Copyright++ 1985, 1988, 1993
5  * -
6  * Copyright (c) 1985, 1988, 1993
7  *    The Regents of the University of California.  All rights reserved.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  * 3. Neither the name of the University nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  * -
33  * Portions Copyright (c) 1993 by Digital Equipment Corporation.
34  *
35  * Permission to use, copy, modify, and distribute this software for any
36  * purpose with or without fee is hereby granted, provided that the above
37  * copyright notice and this permission notice appear in all copies, and that
38  * the name of Digital Equipment Corporation not be used in advertising or
39  * publicity pertaining to distribution of the document or software without
40  * specific, written prior permission.
41  *
42  * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
43  * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
44  * OF MERCHANTABILITY AND FITNESS.   IN NO EVENT SHALL DIGITAL EQUIPMENT
45  * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
46  * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
47  * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
48  * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
49  * SOFTWARE.
50  * -
51  * --Copyright--
52  */
53 
54 #include <sys/cdefs.h>
55 #if defined(LIBC_SCCS) && !defined(lint)
56 #if 0
57 static char sccsid[] = "@(#)gethostnamadr.c	8.1 (Berkeley) 6/4/93";
58 static char rcsid[] = "Id: gethnamaddr.c,v 8.21 1997/06/01 20:34:37 vixie Exp ";
59 #else
60 __RCSID("$NetBSD: gethnamaddr.c,v 1.79 2012/09/09 16:42:23 christos Exp $");
61 #endif
62 #endif /* LIBC_SCCS and not lint */
63 
64 #if defined(_LIBC)
65 #include "namespace.h"
66 #endif
67 #include <sys/param.h>
68 #include <sys/socket.h>
69 #include <netinet/in.h>
70 #include <arpa/inet.h>
71 #include <arpa/nameser.h>
72 
73 #include <assert.h>
74 #include <ctype.h>
75 #include <errno.h>
76 #include <netdb.h>
77 #include <resolv.h>
78 #include <stdarg.h>
79 #include <stdio.h>
80 #include <syslog.h>
81 
82 #ifndef LOG_AUTH
83 # define LOG_AUTH 0
84 #endif
85 
86 #define MULTI_PTRS_ARE_ALIASES 1	/* XXX - experimental */
87 
88 #include <nsswitch.h>
89 #include <stdlib.h>
90 #include <string.h>
91 
92 #ifdef YP
93 #include <rpc/rpc.h>
94 #include <rpcsvc/yp_prot.h>
95 #include <rpcsvc/ypclnt.h>
96 #endif
97 
98 #if defined(_LIBC) && defined(__weak_alias)
99 __weak_alias(gethostbyaddr,_gethostbyaddr)
100 __weak_alias(gethostbyname,_gethostbyname)
101 __weak_alias(gethostent,_gethostent)
102 #endif
103 
104 #define maybe_ok(res, nm, ok) (((res)->options & RES_NOCHECKNAME) != 0U || \
105                                (ok)(nm) != 0)
106 #define maybe_hnok(res, hn) maybe_ok((res), (hn), res_hnok)
107 #define maybe_dnok(res, dn) maybe_ok((res), (dn), res_dnok)
108 
109 
110 #define	MAXALIASES	35
111 #define	MAXADDRS	35
112 
113 static const char AskedForGot[] =
114 			  "gethostby*.getanswer: asked for \"%s\", got \"%s\"";
115 
116 static char *h_addr_ptrs[MAXADDRS + 1];
117 
118 #ifdef YP
119 static char *__ypdomain;
120 #endif
121 
122 static struct hostent host;
123 static char *host_aliases[MAXALIASES];
124 static char hostbuf[8*1024];
125 static u_int32_t host_addr[16 / sizeof(u_int32_t)];	/* IPv4 or IPv6 */
126 static FILE *hostf = NULL;
127 static int stayopen = 0;
128 
129 #define	MAXPACKET	(64*1024)
130 
131 typedef union {
132     HEADER hdr;
133     u_char buf[MAXPACKET];
134 } querybuf;
135 
136 typedef union {
137     int32_t al;
138     char ac;
139 } align;
140 
141 #ifdef DEBUG
142 static void debugprintf(const char *, res_state, ...)
143 	__attribute__((__format__(__printf__, 1, 3)));
144 #endif
145 static struct hostent *getanswer(const querybuf *, int, const char *, int,
146     res_state);
147 static void map_v4v6_address(const char *, char *);
148 static void map_v4v6_hostent(struct hostent *, char **, char *);
149 static void addrsort(char **, int, res_state);
150 
151 void _sethtent(int);
152 void _endhtent(void);
153 struct hostent *_gethtent(void);
154 void ht_sethostent(int);
155 void ht_endhostent(void);
156 struct hostent *ht_gethostbyname(char *);
157 struct hostent *ht_gethostbyaddr(const char *, int, int);
158 void dns_service(void);
159 #undef dn_skipname
160 int dn_skipname(const u_char *, const u_char *);
161 int _gethtbyaddr(void *, void *, va_list);
162 int _gethtbyname(void *, void *, va_list);
163 struct hostent *_gethtbyname2(const char *, int);
164 int _dns_gethtbyaddr(void *, void *, va_list);
165 int _dns_gethtbyname(void *, void *, va_list);
166 #ifdef YP
167 struct hostent *_yphostent(char *, int);
168 int _yp_gethtbyaddr(void *, void *, va_list);
169 int _yp_gethtbyname(void *, void *, va_list);
170 #endif
171 
172 static struct hostent *gethostbyname_internal(const char *, int, res_state);
173 
174 static const ns_src default_dns_files[] = {
175 	{ NSSRC_FILES, 	NS_SUCCESS },
176 	{ NSSRC_DNS, 	NS_SUCCESS },
177 	{ 0, 0 }
178 };
179 
180 
181 #ifdef DEBUG
182 static void
183 debugprintf(const char *msg, res_state res, ...)
184 {
185 	_DIAGASSERT(msg != NULL);
186 
187 	if (res->options & RES_DEBUG) {
188 		int save = errno;
189 		va_list ap;
190 
191 		va_start (ap, res);
192 		vprintf(msg, ap);
193 		va_end (ap);
194 
195 		errno = save;
196 	}
197 }
198 #else
199 # define debugprintf(msg, res, num) /*nada*/
200 #endif
201 
202 #define BOUNDED_INCR(x) \
203 	do { \
204 		cp += (x); \
205 		if (cp > eom) { \
206 			h_errno = NO_RECOVERY; \
207 			return NULL; \
208 		} \
209 	} while (/*CONSTCOND*/0)
210 
211 #define BOUNDS_CHECK(ptr, count) \
212 	do { \
213 		if ((ptr) + (count) > eom) { \
214 			h_errno = NO_RECOVERY; \
215 			return NULL; \
216 		} \
217 	} while (/*CONSTCOND*/0)
218 
219 static struct hostent *
220 getanswer(const querybuf *answer, int anslen, const char *qname, int qtype,
221     res_state res)
222 {
223 	const HEADER *hp;
224 	const u_char *cp;
225 	int n;
226 	const u_char *eom, *erdata;
227 	char *bp, **ap, **hap, *ep;
228 	int type, class, ancount, qdcount;
229 	int haveanswer, had_error;
230 	int toobig = 0;
231 	char tbuf[MAXDNAME];
232 	const char *tname;
233 	int (*name_ok)(const char *);
234 
235 	_DIAGASSERT(answer != NULL);
236 	_DIAGASSERT(qname != NULL);
237 
238 	tname = qname;
239 	host.h_name = NULL;
240 	eom = answer->buf + anslen;
241 	switch (qtype) {
242 	case T_A:
243 	case T_AAAA:
244 		name_ok = res_hnok;
245 		break;
246 	case T_PTR:
247 		name_ok = res_dnok;
248 		break;
249 	default:
250 		return NULL;	/* XXX should be abort(); */
251 	}
252 	/*
253 	 * find first satisfactory answer
254 	 */
255 	hp = &answer->hdr;
256 	ancount = ntohs(hp->ancount);
257 	qdcount = ntohs(hp->qdcount);
258 	bp = hostbuf;
259 	ep = hostbuf + sizeof hostbuf;
260 	cp = answer->buf;
261 	BOUNDED_INCR(HFIXEDSZ);
262 	if (qdcount != 1) {
263 		h_errno = NO_RECOVERY;
264 		return NULL;
265 	}
266 	n = dn_expand(answer->buf, eom, cp, bp, (int)(ep - bp));
267 	if ((n < 0) || !maybe_ok(res, bp, name_ok)) {
268 		h_errno = NO_RECOVERY;
269 		return NULL;
270 	}
271 	BOUNDED_INCR(n + QFIXEDSZ);
272 	if (qtype == T_A || qtype == T_AAAA) {
273 		/* res_send() has already verified that the query name is the
274 		 * same as the one we sent; this just gets the expanded name
275 		 * (i.e., with the succeeding search-domain tacked on).
276 		 */
277 		n = (int)strlen(bp) + 1;		/* for the \0 */
278 		if (n >= MAXHOSTNAMELEN) {
279 			h_errno = NO_RECOVERY;
280 			return NULL;
281 		}
282 		host.h_name = bp;
283 		bp += n;
284 		/* The qname can be abbreviated, but h_name is now absolute. */
285 		qname = host.h_name;
286 	}
287 	ap = host_aliases;
288 	*ap = NULL;
289 	host.h_aliases = host_aliases;
290 	hap = h_addr_ptrs;
291 	*hap = NULL;
292 	host.h_addr_list = h_addr_ptrs;
293 	haveanswer = 0;
294 	had_error = 0;
295 	while (ancount-- > 0 && cp < eom && !had_error) {
296 		n = dn_expand(answer->buf, eom, cp, bp, (int)(ep - bp));
297 		if ((n < 0) || !maybe_ok(res, bp, name_ok)) {
298 			had_error++;
299 			continue;
300 		}
301 		cp += n;			/* name */
302 		BOUNDS_CHECK(cp, 3 * INT16SZ + INT32SZ);
303 		type = _getshort(cp);
304  		cp += INT16SZ;			/* type */
305 		class = _getshort(cp);
306  		cp += INT16SZ + INT32SZ;	/* class, TTL */
307 		n = _getshort(cp);
308 		cp += INT16SZ;			/* len */
309 		BOUNDS_CHECK(cp, n);
310 		erdata = cp + n;
311 		if (class != C_IN) {
312 			/* XXX - debug? syslog? */
313 			cp += n;
314 			continue;		/* XXX - had_error++ ? */
315 		}
316 		if ((qtype == T_A || qtype == T_AAAA) && type == T_CNAME) {
317 			if (ap >= &host_aliases[MAXALIASES-1])
318 				continue;
319 			n = dn_expand(answer->buf, eom, cp, tbuf, (int)sizeof tbuf);
320 			if ((n < 0) || !maybe_ok(res, tbuf, name_ok)) {
321 				had_error++;
322 				continue;
323 			}
324 			cp += n;
325 			if (cp != erdata) {
326 				h_errno = NO_RECOVERY;
327 				return NULL;
328 			}
329 			/* Store alias. */
330 			*ap++ = bp;
331 			n = (int)strlen(bp) + 1;	/* for the \0 */
332 			if (n >= MAXHOSTNAMELEN) {
333 				had_error++;
334 				continue;
335 			}
336 			bp += n;
337 			/* Get canonical name. */
338 			n = (int)strlen(tbuf) + 1;	/* for the \0 */
339 			if (n > ep - bp || n >= MAXHOSTNAMELEN) {
340 				had_error++;
341 				continue;
342 			}
343 			strlcpy(bp, tbuf, (size_t)(ep - bp));
344 			host.h_name = bp;
345 			bp += n;
346 			continue;
347 		}
348 		if (qtype == T_PTR && type == T_CNAME) {
349 			n = dn_expand(answer->buf, eom, cp, tbuf, (int)sizeof tbuf);
350 			if (n < 0 || !maybe_dnok(res, tbuf)) {
351 				had_error++;
352 				continue;
353 			}
354 			cp += n;
355 			if (cp != erdata) {
356 				h_errno = NO_RECOVERY;
357 				return NULL;
358 			}
359 			/* Get canonical name. */
360 			n = (int)strlen(tbuf) + 1;	/* for the \0 */
361 			if (n > ep - bp || n >= MAXHOSTNAMELEN) {
362 				had_error++;
363 				continue;
364 			}
365 			strlcpy(bp, tbuf, (size_t)(ep - bp));
366 			tname = bp;
367 			bp += n;
368 			continue;
369 		}
370 		if (type != qtype) {
371 			if (type != T_KEY && type != T_SIG)
372 				syslog(LOG_NOTICE|LOG_AUTH,
373 	       "gethostby*.getanswer: asked for \"%s %s %s\", got type \"%s\"",
374 				       qname, p_class(C_IN), p_type(qtype),
375 				       p_type(type));
376 			cp += n;
377 			continue;		/* XXX - had_error++ ? */
378 		}
379 		switch (type) {
380 		case T_PTR:
381 			if (strcasecmp(tname, bp) != 0) {
382 				syslog(LOG_NOTICE|LOG_AUTH,
383 				       AskedForGot, qname, bp);
384 				cp += n;
385 				continue;	/* XXX - had_error++ ? */
386 			}
387 			n = dn_expand(answer->buf, eom, cp, bp, (int)(ep - bp));
388 			if ((n < 0) || !maybe_hnok(res, bp)) {
389 				had_error++;
390 				break;
391 			}
392 #if MULTI_PTRS_ARE_ALIASES
393 			cp += n;
394 			if (cp != erdata) {
395 				h_errno = NO_RECOVERY;
396 				return NULL;
397 			}
398 			if (!haveanswer)
399 				host.h_name = bp;
400 			else if (ap < &host_aliases[MAXALIASES-1])
401 				*ap++ = bp;
402 			else
403 				n = -1;
404 			if (n != -1) {
405 				n = (int)strlen(bp) + 1;	/* for the \0 */
406 				if (n >= MAXHOSTNAMELEN) {
407 					had_error++;
408 					break;
409 				}
410 				bp += n;
411 			}
412 			break;
413 #else
414 			host.h_name = bp;
415 			if (res->options & RES_USE_INET6) {
416 				n = strlen(bp) + 1;	/* for the \0 */
417 				if (n >= MAXHOSTNAMELEN) {
418 					had_error++;
419 					break;
420 				}
421 				bp += n;
422 				map_v4v6_hostent(&host, &bp, ep);
423 			}
424 			h_errno = NETDB_SUCCESS;
425 			return &host;
426 #endif
427 		case T_A:
428 		case T_AAAA:
429 			if (strcasecmp(host.h_name, bp) != 0) {
430 				syslog(LOG_NOTICE|LOG_AUTH,
431 				       AskedForGot, host.h_name, bp);
432 				cp += n;
433 				continue;	/* XXX - had_error++ ? */
434 			}
435 			if (n != host.h_length) {
436 				cp += n;
437 				continue;
438 			}
439 			if (type == T_AAAA) {
440 				struct in6_addr in6;
441 				memcpy(&in6, cp, IN6ADDRSZ);
442 				if (IN6_IS_ADDR_V4MAPPED(&in6)) {
443 					cp += n;
444 					continue;
445 				}
446 			}
447 			if (!haveanswer) {
448 				int nn;
449 
450 				host.h_name = bp;
451 				nn = (int)strlen(bp) + 1;	/* for the \0 */
452 				bp += nn;
453 			}
454 
455 			bp += sizeof(align) -
456 			    (size_t)((u_long)bp % sizeof(align));
457 
458 			if (bp + n >= &hostbuf[sizeof hostbuf]) {
459 				debugprintf("size (%d) too big\n", res, n);
460 				had_error++;
461 				continue;
462 			}
463 			if (hap >= &h_addr_ptrs[MAXADDRS-1]) {
464 				if (!toobig++) {
465 					debugprintf("Too many addresses (%d)\n",
466 						res, MAXADDRS);
467 				}
468 				cp += n;
469 				continue;
470 			}
471 			(void)memcpy(*hap++ = bp, cp, (size_t)n);
472 			bp += n;
473 			cp += n;
474 			if (cp != erdata) {
475 				h_errno = NO_RECOVERY;
476 				return NULL;
477 			}
478 			break;
479 		default:
480 			abort();
481 		}
482 		if (!had_error)
483 			haveanswer++;
484 	}
485 	if (haveanswer) {
486 		*ap = NULL;
487 		*hap = NULL;
488 		/*
489 		 * Note: we sort even if host can take only one address
490 		 * in its return structures - should give it the "best"
491 		 * address in that case, not some random one
492 		 */
493 		if (res->nsort && haveanswer > 1 && qtype == T_A)
494 			addrsort(h_addr_ptrs, haveanswer, res);
495 		if (!host.h_name) {
496 			n = (int)strlen(qname) + 1;	/* for the \0 */
497 			if (n > ep - bp || n >= MAXHOSTNAMELEN)
498 				goto no_recovery;
499 			strlcpy(bp, qname, (size_t)(ep - bp));
500 			host.h_name = bp;
501 			bp += n;
502 		}
503 		if (res->options & RES_USE_INET6)
504 			map_v4v6_hostent(&host, &bp, ep);
505 		h_errno = NETDB_SUCCESS;
506 		return &host;
507 	}
508  no_recovery:
509 	h_errno = NO_RECOVERY;
510 	return NULL;
511 }
512 
513 struct hostent *
514 gethostbyname(const char *name)
515 {
516 	struct hostent *hp;
517 	res_state res = __res_get_state();
518 
519 	if (res == NULL)
520 		return NULL;
521 
522 	_DIAGASSERT(name != NULL);
523 
524 	if (res->options & RES_USE_INET6) {
525 		hp = gethostbyname_internal(name, AF_INET6, res);
526 		if (hp) {
527 			__res_put_state(res);
528 			return hp;
529 		}
530 	}
531 	hp = gethostbyname_internal(name, AF_INET, res);
532 	__res_put_state(res);
533 	return hp;
534 }
535 
536 struct hostent *
537 gethostbyname2(const char *name, int af)
538 {
539 	struct hostent *hp;
540 	res_state res = __res_get_state();
541 
542 	if (res == NULL)
543 		return NULL;
544 	hp = gethostbyname_internal(name, af, res);
545 	__res_put_state(res);
546 	return hp;
547 }
548 
549 static struct hostent *
550 gethostbyname_internal(const char *name, int af, res_state res)
551 {
552 	const char *cp;
553 	char *bp, *ep;
554 	int size;
555 	struct hostent *hp;
556 	static const ns_dtab dtab[] = {
557 		NS_FILES_CB(_gethtbyname, NULL)
558 		{ NSSRC_DNS, _dns_gethtbyname, NULL },	/* force -DHESIOD */
559 		NS_NIS_CB(_yp_gethtbyname, NULL)
560 		NS_NULL_CB
561 	};
562 
563 	_DIAGASSERT(name != NULL);
564 
565 	switch (af) {
566 	case AF_INET:
567 		size = INADDRSZ;
568 		break;
569 	case AF_INET6:
570 		size = IN6ADDRSZ;
571 		break;
572 	default:
573 		h_errno = NETDB_INTERNAL;
574 		errno = EAFNOSUPPORT;
575 		return NULL;
576 	}
577 
578 	host.h_addrtype = af;
579 	host.h_length = size;
580 
581 	/*
582 	 * if there aren't any dots, it could be a user-level alias.
583 	 * this is also done in res_nquery() since we are not the only
584 	 * function that looks up host names.
585 	 */
586 	if (!strchr(name, '.') && (cp = __hostalias(name)))
587 		name = cp;
588 
589 	/*
590 	 * disallow names consisting only of digits/dots, unless
591 	 * they end in a dot.
592 	 */
593 	if (isdigit((u_char) name[0]))
594 		for (cp = name;; ++cp) {
595 			if (!*cp) {
596 				if (*--cp == '.')
597 					break;
598 				/*
599 				 * All-numeric, no dot at the end.
600 				 * Fake up a hostent as if we'd actually
601 				 * done a lookup.
602 				 */
603 				if (inet_pton(af, name,
604 				    (char *)(void *)host_addr) <= 0) {
605 					h_errno = HOST_NOT_FOUND;
606 					return NULL;
607 				}
608 				strncpy(hostbuf, name, MAXDNAME);
609 				hostbuf[MAXDNAME] = '\0';
610 				bp = hostbuf + MAXDNAME;
611 				ep = hostbuf + sizeof hostbuf;
612 				host.h_name = hostbuf;
613 				host.h_aliases = host_aliases;
614 				host_aliases[0] = NULL;
615 				h_addr_ptrs[0] = (char *)(void *)host_addr;
616 				h_addr_ptrs[1] = NULL;
617 				host.h_addr_list = h_addr_ptrs;
618 				if (res->options & RES_USE_INET6)
619 					map_v4v6_hostent(&host, &bp, ep);
620 				h_errno = NETDB_SUCCESS;
621 				return &host;
622 			}
623 			if (!isdigit((u_char) *cp) && *cp != '.')
624 				break;
625 		}
626 	if ((isxdigit((u_char) name[0]) && strchr(name, ':') != NULL) ||
627 	    name[0] == ':')
628 		for (cp = name;; ++cp) {
629 			if (!*cp) {
630 				if (*--cp == '.')
631 					break;
632 				/*
633 				 * All-IPv6-legal, no dot at the end.
634 				 * Fake up a hostent as if we'd actually
635 				 * done a lookup.
636 				 */
637 				if (inet_pton(af, name,
638 				    (char *)(void *)host_addr) <= 0) {
639 					h_errno = HOST_NOT_FOUND;
640 					return NULL;
641 				}
642 				strncpy(hostbuf, name, MAXDNAME);
643 				hostbuf[MAXDNAME] = '\0';
644 				bp = hostbuf + MAXDNAME;
645 				ep = hostbuf + sizeof hostbuf;
646 				host.h_name = hostbuf;
647 				host.h_aliases = host_aliases;
648 				host_aliases[0] = NULL;
649 				h_addr_ptrs[0] = (char *)(void *)host_addr;
650 				h_addr_ptrs[1] = NULL;
651 				host.h_addr_list = h_addr_ptrs;
652 				h_errno = NETDB_SUCCESS;
653 				return &host;
654 			}
655 			if (!isxdigit((u_char) *cp) && *cp != ':' && *cp != '.')
656 				break;
657 		}
658 
659 	hp = NULL;
660 	h_errno = NETDB_INTERNAL;
661 	if (nsdispatch(&hp, dtab, NSDB_HOSTS, "gethostbyname",
662 	    default_dns_files, name, strlen(name), af) != NS_SUCCESS)
663 		return NULL;
664 	h_errno = NETDB_SUCCESS;
665 	return hp;
666 }
667 
668 struct hostent *
669 gethostbyaddr(const char *addr,	/* XXX should have been def'd as u_char! */
670     socklen_t len, int af)
671 {
672 	const u_char *uaddr = (const u_char *)addr;
673 	socklen_t size;
674 	struct hostent *hp;
675 	static const ns_dtab dtab[] = {
676 		NS_FILES_CB(_gethtbyaddr, NULL)
677 		{ NSSRC_DNS, _dns_gethtbyaddr, NULL },	/* force -DHESIOD */
678 		NS_NIS_CB(_yp_gethtbyaddr, NULL)
679 		NS_NULL_CB
680 	};
681 
682 	_DIAGASSERT(addr != NULL);
683 
684 	if (af == AF_INET6 && len == IN6ADDRSZ &&
685 	    (IN6_IS_ADDR_LINKLOCAL((const struct in6_addr *)(const void *)uaddr) ||
686 	     IN6_IS_ADDR_SITELOCAL((const struct in6_addr *)(const void *)uaddr))) {
687 		h_errno = HOST_NOT_FOUND;
688 		return NULL;
689 	}
690 	if (af == AF_INET6 && len == IN6ADDRSZ &&
691 	    (IN6_IS_ADDR_V4MAPPED((const struct in6_addr *)(const void *)uaddr) ||
692 	     IN6_IS_ADDR_V4COMPAT((const struct in6_addr *)(const void *)uaddr))) {
693 		/* Unmap. */
694 		addr += IN6ADDRSZ - INADDRSZ;
695 		uaddr += IN6ADDRSZ - INADDRSZ;
696 		af = AF_INET;
697 		len = INADDRSZ;
698 	}
699 	switch (af) {
700 	case AF_INET:
701 		size = INADDRSZ;
702 		break;
703 	case AF_INET6:
704 		size = IN6ADDRSZ;
705 		break;
706 	default:
707 		errno = EAFNOSUPPORT;
708 		h_errno = NETDB_INTERNAL;
709 		return NULL;
710 	}
711 	if (size != len) {
712 		errno = EINVAL;
713 		h_errno = NETDB_INTERNAL;
714 		return NULL;
715 	}
716 	hp = NULL;
717 	h_errno = NETDB_INTERNAL;
718 	if (nsdispatch(&hp, dtab, NSDB_HOSTS, "gethostbyaddr",
719 	    default_dns_files, uaddr, len, af) != NS_SUCCESS)
720 		return NULL;
721 	h_errno = NETDB_SUCCESS;
722 	return hp;
723 }
724 
725 void
726 _sethtent(int f)
727 {
728 	if (!hostf)
729 		hostf = fopen(_PATH_HOSTS, "re");
730 	else
731 		rewind(hostf);
732 	stayopen = f;
733 }
734 
735 void
736 _endhtent(void)
737 {
738 	if (hostf && !stayopen) {
739 		(void) fclose(hostf);
740 		hostf = NULL;
741 	}
742 }
743 
744 struct hostent *
745 _gethtent(void)
746 {
747 	char *p;
748 	char *cp, **q;
749 	int af, len;
750 
751 	if (!hostf && !(hostf = fopen(_PATH_HOSTS, "re"))) {
752 		h_errno = NETDB_INTERNAL;
753 		return NULL;
754 	}
755  again:
756 	if (!(p = fgets(hostbuf, (int)sizeof hostbuf, hostf))) {
757 		h_errno = HOST_NOT_FOUND;
758 		return NULL;
759 	}
760 	if (*p == '#')
761 		goto again;
762 	if (!(cp = strpbrk(p, "#\n")))
763 		goto again;
764 	*cp = '\0';
765 	if (!(cp = strpbrk(p, " \t")))
766 		goto again;
767 	*cp++ = '\0';
768 	if (inet_pton(AF_INET6, p, (char *)(void *)host_addr) > 0) {
769 		af = AF_INET6;
770 		len = IN6ADDRSZ;
771 	} else if (inet_pton(AF_INET, p, (char *)(void *)host_addr) > 0) {
772 		res_state res = __res_get_state();
773 		if (res == NULL)
774 			return NULL;
775 		if (res->options & RES_USE_INET6) {
776 			map_v4v6_address((char *)(void *)host_addr,
777 			    (char *)(void *)host_addr);
778 			af = AF_INET6;
779 			len = IN6ADDRSZ;
780 		} else {
781 			af = AF_INET;
782 			len = INADDRSZ;
783 		}
784 		__res_put_state(res);
785 	} else {
786 		goto again;
787 	}
788 	/* if this is not something we're looking for, skip it. */
789 	if (host.h_addrtype != 0 && host.h_addrtype != af)
790 		goto again;
791 	if (host.h_length != 0 && host.h_length != len)
792 		goto again;
793 	h_addr_ptrs[0] = (char *)(void *)host_addr;
794 	h_addr_ptrs[1] = NULL;
795 	host.h_addr_list = h_addr_ptrs;
796 	host.h_length = len;
797 	host.h_addrtype = af;
798 	while (*cp == ' ' || *cp == '\t')
799 		cp++;
800 	host.h_name = cp;
801 	q = host.h_aliases = host_aliases;
802 	if ((cp = strpbrk(cp, " \t")) != NULL)
803 		*cp++ = '\0';
804 	while (cp && *cp) {
805 		if (*cp == ' ' || *cp == '\t') {
806 			cp++;
807 			continue;
808 		}
809 		if (q < &host_aliases[MAXALIASES - 1])
810 			*q++ = cp;
811 		if ((cp = strpbrk(cp, " \t")) != NULL)
812 			*cp++ = '\0';
813 	}
814 	*q = NULL;
815 	h_errno = NETDB_SUCCESS;
816 	return &host;
817 }
818 
819 /*ARGSUSED*/
820 int
821 _gethtbyname(void *rv, void *cb_data, va_list ap)
822 {
823 	struct hostent *hp;
824 	const char *name;
825 	int af;
826 
827 	_DIAGASSERT(rv != NULL);
828 
829 	name = va_arg(ap, char *);
830 	/* NOSTRICT skip len */(void)va_arg(ap, int);
831 	af = va_arg(ap, int);
832 
833 	hp = NULL;
834 #if 0
835 	{
836 		res_state res = __res_get_state();
837 		if (res == NULL)
838 			return NS_NOTFOUND;
839 		if (res->options & RES_USE_INET6)
840 			hp = _gethtbyname2(name, AF_INET6);
841 		if (hp==NULL)
842 			hp = _gethtbyname2(name, AF_INET);
843 		__res_put_state(res);
844 	}
845 #else
846 	hp = _gethtbyname2(name, af);
847 #endif
848 	*((struct hostent **)rv) = hp;
849 	if (hp == NULL) {
850 		h_errno = HOST_NOT_FOUND;
851 		return NS_NOTFOUND;
852 	}
853 	return NS_SUCCESS;
854 }
855 
856 struct hostent *
857 _gethtbyname2(const char *name, int af)
858 {
859 	struct hostent *p;
860 	char *tmpbuf, *ptr, **cp;
861 	int num;
862 	size_t len;
863 
864 	_DIAGASSERT(name != NULL);
865 
866 	_sethtent(stayopen);
867 	ptr = tmpbuf = NULL;
868 	num = 0;
869 	while ((p = _gethtent()) != NULL && num < MAXADDRS) {
870 		if (p->h_addrtype != af)
871 			continue;
872 		if (strcasecmp(p->h_name, name) != 0) {
873 			for (cp = p->h_aliases; *cp != NULL; cp++)
874 				if (strcasecmp(*cp, name) == 0)
875 					break;
876 			if (*cp == NULL) continue;
877 		}
878 
879 		if (num == 0) {
880 			size_t bufsize;
881 			char *src;
882 
883 			bufsize = strlen(p->h_name) + 2 +
884 				  MAXADDRS * p->h_length +
885 				  ALIGNBYTES;
886 			for (cp = p->h_aliases; *cp != NULL; cp++)
887 				bufsize += strlen(*cp) + 1;
888 
889 			if ((tmpbuf = malloc(bufsize)) == NULL) {
890 				h_errno = NETDB_INTERNAL;
891 				return NULL;
892 			}
893 
894 			ptr = tmpbuf;
895 			src = p->h_name;
896 			while ((*ptr++ = *src++) != '\0');
897 			for (cp = p->h_aliases; *cp != NULL; cp++) {
898 				src = *cp;
899 				while ((*ptr++ = *src++) != '\0');
900 			}
901 			*ptr++ = '\0';
902 
903 			ptr = (char *)(void *)ALIGN(ptr);
904 		}
905 
906 		(void)memcpy(ptr, p->h_addr_list[0], (size_t)p->h_length);
907 		ptr += p->h_length;
908 		num++;
909 	}
910 	_endhtent();
911 	if (num == 0) return NULL;
912 
913 	len = ptr - tmpbuf;
914 	if (len > (sizeof(hostbuf) - ALIGNBYTES)) {
915 		free(tmpbuf);
916 		errno = ENOSPC;
917 		h_errno = NETDB_INTERNAL;
918 		return NULL;
919 	}
920 	ptr = memcpy((void *)ALIGN(hostbuf), tmpbuf, len);
921 	free(tmpbuf);
922 
923 	host.h_name = ptr;
924 	while (*ptr++);
925 
926 	cp = host_aliases;
927 	while (*ptr) {
928 		*cp++ = ptr;
929 		while (*ptr++);
930 	}
931 	ptr++;
932 	*cp = NULL;
933 
934 	ptr = (char *)(void *)ALIGN(ptr);
935 	cp = h_addr_ptrs;
936 	while (num--) {
937 		*cp++ = ptr;
938 		ptr += host.h_length;
939 	}
940 	*cp = NULL;
941 
942 	return &host;
943 }
944 
945 /*ARGSUSED*/
946 int
947 _gethtbyaddr(void *rv, void *cb_data, va_list ap)
948 {
949 	struct hostent *p;
950 	const unsigned char *addr;
951 	int len, af;
952 
953 	_DIAGASSERT(rv != NULL);
954 
955 	addr = va_arg(ap, unsigned char *);
956 	len = va_arg(ap, int);
957 	af = va_arg(ap, int);
958 
959 	host.h_length = len;
960 	host.h_addrtype = af;
961 
962 	_sethtent(stayopen);
963 	while ((p = _gethtent()) != NULL)
964 		if (p->h_addrtype == af && !memcmp(p->h_addr, addr,
965 		    (size_t)len))
966 			break;
967 	_endhtent();
968 	*((struct hostent **)rv) = p;
969 	if (p==NULL) {
970 		h_errno = HOST_NOT_FOUND;
971 		return NS_NOTFOUND;
972 	}
973 	return NS_SUCCESS;
974 }
975 
976 static void
977 map_v4v6_address(const char *src, char *dst)
978 {
979 	u_char *p = (u_char *)dst;
980 	char tmp[INADDRSZ];
981 	int i;
982 
983 	_DIAGASSERT(src != NULL);
984 	_DIAGASSERT(dst != NULL);
985 
986 	/* Stash a temporary copy so our caller can update in place. */
987 	(void)memcpy(tmp, src, INADDRSZ);
988 	/* Mark this ipv6 addr as a mapped ipv4. */
989 	for (i = 0; i < 10; i++)
990 		*p++ = 0x00;
991 	*p++ = 0xff;
992 	*p++ = 0xff;
993 	/* Retrieve the saved copy and we're done. */
994 	(void)memcpy((void *)p, tmp, INADDRSZ);
995 }
996 
997 static void
998 map_v4v6_hostent(struct hostent *hp, char **bpp, char *ep)
999 {
1000 	char **ap;
1001 
1002 	_DIAGASSERT(hp != NULL);
1003 	_DIAGASSERT(bpp != NULL);
1004 	_DIAGASSERT(ep != NULL);
1005 
1006 	if (hp->h_addrtype != AF_INET || hp->h_length != INADDRSZ)
1007 		return;
1008 	hp->h_addrtype = AF_INET6;
1009 	hp->h_length = IN6ADDRSZ;
1010 	for (ap = hp->h_addr_list; *ap; ap++) {
1011 		int i = (int)(sizeof(align) -
1012 		    (size_t)((u_long)*bpp % sizeof(align)));
1013 
1014 		if (ep - *bpp < (i + IN6ADDRSZ)) {
1015 			/* Out of memory.  Truncate address list here.  XXX */
1016 			*ap = NULL;
1017 			return;
1018 		}
1019 		*bpp += i;
1020 		map_v4v6_address(*ap, *bpp);
1021 		*ap = *bpp;
1022 		*bpp += IN6ADDRSZ;
1023 	}
1024 }
1025 
1026 static void
1027 addrsort(char **ap, int num, res_state res)
1028 {
1029 	int i, j;
1030 	char **p;
1031 	short aval[MAXADDRS];
1032 	int needsort = 0;
1033 
1034 	_DIAGASSERT(ap != NULL);
1035 
1036 	p = ap;
1037 	for (i = 0; i < num; i++, p++) {
1038 	    for (j = 0 ; (unsigned)j < res->nsort; j++)
1039 		if (res->sort_list[j].addr.s_addr ==
1040 		    (((struct in_addr *)(void *)(*p))->s_addr &
1041 		    res->sort_list[j].mask))
1042 			break;
1043 	    aval[i] = j;
1044 	    if (needsort == 0 && i > 0 && j < aval[i-1])
1045 		needsort = i;
1046 	}
1047 	if (!needsort)
1048 	    return;
1049 
1050 	while (needsort < num) {
1051 	    for (j = needsort - 1; j >= 0; j--) {
1052 		if (aval[j] > aval[j+1]) {
1053 		    char *hp;
1054 
1055 		    i = aval[j];
1056 		    aval[j] = aval[j+1];
1057 		    aval[j+1] = i;
1058 
1059 		    hp = ap[j];
1060 		    ap[j] = ap[j+1];
1061 		    ap[j+1] = hp;
1062 		} else
1063 		    break;
1064 	    }
1065 	    needsort++;
1066 	}
1067 }
1068 
1069 struct hostent *
1070 gethostent(void)
1071 {
1072 	host.h_addrtype = 0;
1073 	host.h_length = 0;
1074 	return _gethtent();
1075 }
1076 
1077 /*ARGSUSED*/
1078 int
1079 _dns_gethtbyname(void *rv, void *cb_data, va_list ap)
1080 {
1081 	querybuf *buf;
1082 	int n, type;
1083 	struct hostent *hp;
1084 	const char *name;
1085 	int af;
1086 	res_state res;
1087 
1088 	_DIAGASSERT(rv != NULL);
1089 
1090 	name = va_arg(ap, char *);
1091 	/* NOSTRICT skip len */(void)va_arg(ap, int);
1092 	af = va_arg(ap, int);
1093 
1094 	switch (af) {
1095 	case AF_INET:
1096 		type = T_A;
1097 		break;
1098 	case AF_INET6:
1099 		type = T_AAAA;
1100 		break;
1101 	default:
1102 		return NS_UNAVAIL;
1103 	}
1104 	buf = malloc(sizeof(*buf));
1105 	if (buf == NULL) {
1106 		h_errno = NETDB_INTERNAL;
1107 		return NS_NOTFOUND;
1108 	}
1109 	res = __res_get_state();
1110 	if (res == NULL) {
1111 		free(buf);
1112 		return NS_NOTFOUND;
1113 	}
1114 	n = res_nsearch(res, name, C_IN, type, buf->buf, (int)sizeof(buf->buf));
1115 	if (n < 0) {
1116 		free(buf);
1117 		debugprintf("res_nsearch failed (%d)\n", res, n);
1118 		__res_put_state(res);
1119 		return NS_NOTFOUND;
1120 	}
1121 	hp = getanswer(buf, n, name, type, res);
1122 	free(buf);
1123 	__res_put_state(res);
1124 	if (hp == NULL)
1125 		switch (h_errno) {
1126 		case HOST_NOT_FOUND:
1127 			return NS_NOTFOUND;
1128 		case TRY_AGAIN:
1129 			return NS_TRYAGAIN;
1130 		default:
1131 			return NS_UNAVAIL;
1132 		}
1133 	*((struct hostent **)rv) = hp;
1134 	return NS_SUCCESS;
1135 }
1136 
1137 /*ARGSUSED*/
1138 int
1139 _dns_gethtbyaddr(void *rv, void	*cb_data, va_list ap)
1140 {
1141 	char qbuf[MAXDNAME + 1], *qp, *ep;
1142 	int n;
1143 	querybuf *buf;
1144 	struct hostent *hp;
1145 	const unsigned char *uaddr;
1146 	int len, af, advance;
1147 	res_state res;
1148 
1149 	_DIAGASSERT(rv != NULL);
1150 
1151 	uaddr = va_arg(ap, unsigned char *);
1152 	len = va_arg(ap, int);
1153 	af = va_arg(ap, int);
1154 
1155 	switch (af) {
1156 	case AF_INET:
1157 		(void)snprintf(qbuf, sizeof(qbuf), "%u.%u.%u.%u.in-addr.arpa",
1158 		    (uaddr[3] & 0xff), (uaddr[2] & 0xff),
1159 		    (uaddr[1] & 0xff), (uaddr[0] & 0xff));
1160 		break;
1161 
1162 	case AF_INET6:
1163 		qp = qbuf;
1164 		ep = qbuf + sizeof(qbuf) - 1;
1165 		for (n = IN6ADDRSZ - 1; n >= 0; n--) {
1166 			advance = snprintf(qp, (size_t)(ep - qp), "%x.%x.",
1167 			    uaddr[n] & 0xf,
1168 			    ((unsigned int)uaddr[n] >> 4) & 0xf);
1169 			if (advance > 0 && qp + advance < ep)
1170 				qp += advance;
1171 			else {
1172 				h_errno = NETDB_INTERNAL;
1173 				return NS_NOTFOUND;
1174 			}
1175 		}
1176 		if (strlcat(qbuf, "ip6.arpa", sizeof(qbuf)) >= sizeof(qbuf)) {
1177 			h_errno = NETDB_INTERNAL;
1178 			return NS_NOTFOUND;
1179 		}
1180 		break;
1181 	default:
1182 		abort();
1183 	}
1184 
1185 	buf = malloc(sizeof(*buf));
1186 	if (buf == NULL) {
1187 		h_errno = NETDB_INTERNAL;
1188 		return NS_NOTFOUND;
1189 	}
1190 	res = __res_get_state();
1191 	if (res == NULL) {
1192 		free(buf);
1193 		return NS_NOTFOUND;
1194 	}
1195 	n = res_nquery(res, qbuf, C_IN, T_PTR, buf->buf, (int)sizeof(buf->buf));
1196 	if (n < 0) {
1197 		free(buf);
1198 		debugprintf("res_nquery failed (%d)\n", res, n);
1199 		__res_put_state(res);
1200 		return NS_NOTFOUND;
1201 	}
1202 	hp = getanswer(buf, n, qbuf, T_PTR, res);
1203 	free(buf);
1204 	if (hp == NULL) {
1205 		__res_put_state(res);
1206 		switch (h_errno) {
1207 		case HOST_NOT_FOUND:
1208 			return NS_NOTFOUND;
1209 		case TRY_AGAIN:
1210 			return NS_TRYAGAIN;
1211 		default:
1212 			return NS_UNAVAIL;
1213 		}
1214 	}
1215 	hp->h_addrtype = af;
1216 	hp->h_length = len;
1217 	(void)memcpy(host_addr, uaddr, (size_t)len);
1218 	h_addr_ptrs[0] = (char *)(void *)host_addr;
1219 	h_addr_ptrs[1] = NULL;
1220 	if (af == AF_INET && (res->options & RES_USE_INET6)) {
1221 		map_v4v6_address((char *)(void *)host_addr,
1222 		    (char *)(void *)host_addr);
1223 		hp->h_addrtype = AF_INET6;
1224 		hp->h_length = IN6ADDRSZ;
1225 	}
1226 
1227 	__res_put_state(res);
1228 	*((struct hostent **)rv) = hp;
1229 	h_errno = NETDB_SUCCESS;
1230 	return NS_SUCCESS;
1231 }
1232 
1233 #ifdef YP
1234 /*ARGSUSED*/
1235 struct hostent *
1236 _yphostent(char *line, int af)
1237 {
1238 	static struct in_addr host_addrs[MAXADDRS];
1239 	static struct in6_addr host6_addrs[MAXADDRS];
1240 	char *p = line;
1241 	char *cp, **q;
1242 	char **hap;
1243 	int addrok;
1244 	int more;
1245 	size_t naddrs;
1246 
1247 	_DIAGASSERT(line != NULL);
1248 
1249 	host.h_name = NULL;
1250 	host.h_addr_list = h_addr_ptrs;
1251 	host.h_addrtype = af;
1252 	switch (af) {
1253 	case AF_INET:
1254 		host.h_length = INADDRSZ;
1255 		break;
1256 	case AF_INET6:
1257 		host.h_length = IN6ADDRSZ;
1258 		break;
1259 	default:
1260 		return NULL;
1261 	}
1262 	hap = h_addr_ptrs;
1263 	q = host.h_aliases = host_aliases;
1264 	naddrs = 0;
1265 
1266 nextline:
1267 	/* check for host_addrs overflow */
1268 	if (naddrs >= sizeof(host_addrs) / sizeof(host_addrs[0]))
1269 		goto done;
1270 	if (naddrs >= sizeof(host6_addrs) / sizeof(host6_addrs[0]))
1271 		goto done;
1272 
1273 	more = 0;
1274 	cp = strpbrk(p, " \t");
1275 	if (cp == NULL)
1276 		goto done;
1277 	*cp++ = '\0';
1278 
1279 	/* p has should have an address */
1280 	addrok = 0;
1281 	switch (af) {
1282 	case AF_INET:
1283 		addrok = inet_aton(p, &host_addrs[naddrs]);
1284 		break;
1285 	case AF_INET6:
1286 		addrok = inet_pton(af, p, &host6_addrs[naddrs]);
1287 		break;
1288 	}
1289 	if (addrok != 1) {
1290 		/* skip to the next line */
1291 		while (cp && *cp) {
1292 			if (*cp == '\n') {
1293 				cp++;
1294 				goto nextline;
1295 			}
1296 			cp++;
1297 		}
1298 
1299 		goto done;
1300 	}
1301 
1302 	switch (af) {
1303 	case AF_INET:
1304 		*hap++ = (char *)(void *)&host_addrs[naddrs++];
1305 		break;
1306 	case AF_INET6:
1307 		*hap++ = (char *)(void *)&host6_addrs[naddrs++];
1308 		break;
1309 	}
1310 
1311 	while (*cp == ' ' || *cp == '\t')
1312 		cp++;
1313 	p = cp;
1314 	cp = strpbrk(p, " \t\n");
1315 	if (cp != NULL) {
1316 		if (*cp == '\n')
1317 			more = 1;
1318 		*cp++ = '\0';
1319 	}
1320 	if (!host.h_name)
1321 		host.h_name = p;
1322 	else if (strcmp(host.h_name, p)==0)
1323 		;
1324 	else if (q < &host_aliases[MAXALIASES - 1])
1325 		*q++ = p;
1326 	p = cp;
1327 	if (more)
1328 		goto nextline;
1329 
1330 	while (cp && *cp) {
1331 		if (*cp == ' ' || *cp == '\t') {
1332 			cp++;
1333 			continue;
1334 		}
1335 		if (*cp == '\n') {
1336 			cp++;
1337 			goto nextline;
1338 		}
1339 		if (q < &host_aliases[MAXALIASES - 1])
1340 			*q++ = cp;
1341 		cp = strpbrk(cp, " \t");
1342 		if (cp != NULL)
1343 			*cp++ = '\0';
1344 	}
1345 
1346 done:
1347 	if (host.h_name == NULL)
1348 		return NULL;
1349 	*q = NULL;
1350 	*hap = NULL;
1351 	return &host;
1352 }
1353 
1354 /*ARGSUSED*/
1355 int
1356 _yp_gethtbyaddr(void *rv, void *cb_data, va_list ap)
1357 {
1358 	struct hostent *hp = NULL;
1359 	static char *__ypcurrent;
1360 	int __ypcurrentlen, r;
1361 	char name[INET6_ADDRSTRLEN];	/* XXX enough? */
1362 	const unsigned char *uaddr;
1363 	int af;
1364 	const char *map;
1365 
1366 	_DIAGASSERT(rv != NULL);
1367 
1368 	uaddr = va_arg(ap, unsigned char *);
1369 	/* NOSTRICT skip len */(void)va_arg(ap, int);
1370 	af = va_arg(ap, int);
1371 
1372 	if (!__ypdomain) {
1373 		if (_yp_check(&__ypdomain) == 0)
1374 			return NS_UNAVAIL;
1375 	}
1376 	/*
1377 	 * XXX unfortunately, we cannot support IPv6 extended scoped address
1378 	 * notation here.  gethostbyaddr() is not scope-aware.  too bad.
1379 	 */
1380 	if (inet_ntop(af, uaddr, name, (socklen_t)sizeof(name)) == NULL)
1381 		return NS_UNAVAIL;
1382 	if (__ypcurrent)
1383 		free(__ypcurrent);
1384 	__ypcurrent = NULL;
1385 	switch (af) {
1386 	case AF_INET:
1387 		map = "hosts.byaddr";
1388 		break;
1389 	default:
1390 		map = "ipnodes.byaddr";
1391 		break;
1392 	}
1393 	r = yp_match(__ypdomain, map, name,
1394 		(int)strlen(name), &__ypcurrent, &__ypcurrentlen);
1395 	if (r == 0)
1396 		hp = _yphostent(__ypcurrent, af);
1397 	if (hp == NULL) {
1398 		h_errno = HOST_NOT_FOUND;
1399 		return NS_NOTFOUND;
1400 	}
1401 	*((struct hostent **)rv) = hp;
1402 	return NS_SUCCESS;
1403 }
1404 
1405 /*ARGSUSED*/
1406 int
1407 _yp_gethtbyname(void *rv, void *cb_data, va_list ap)
1408 {
1409 	struct hostent *hp = NULL;
1410 	static char *__ypcurrent;
1411 	int __ypcurrentlen, r;
1412 	const char *name;
1413 	int af;
1414 	const char *map;
1415 
1416 	_DIAGASSERT(rv != NULL);
1417 
1418 	name = va_arg(ap, char *);
1419 	/* NOSTRICT skip len */(void)va_arg(ap, int);
1420 	af = va_arg(ap, int);
1421 
1422 	if (!__ypdomain) {
1423 		if (_yp_check(&__ypdomain) == 0)
1424 			return NS_UNAVAIL;
1425 	}
1426 	if (__ypcurrent)
1427 		free(__ypcurrent);
1428 	__ypcurrent = NULL;
1429 	switch (af) {
1430 	case AF_INET:
1431 		map = "hosts.byname";
1432 		break;
1433 	default:
1434 		map = "ipnodes.byname";
1435 		break;
1436 	}
1437 	r = yp_match(__ypdomain, map, name,
1438 		(int)strlen(name), &__ypcurrent, &__ypcurrentlen);
1439 	if (r == 0)
1440 		hp = _yphostent(__ypcurrent, af);
1441 	if (hp == NULL) {
1442 		h_errno = HOST_NOT_FOUND;
1443 		return NS_NOTFOUND;
1444 	}
1445 	*((struct hostent **)rv) = hp;
1446 	return NS_SUCCESS;
1447 }
1448 #endif
1449