thread safer libc (note: safer, not safe)

Access to the global _res structure replaced by pointers to a
per thread instance.  If unthreaded the pointer is to the
global structure.

Also replaced a 64k stack array with malloc-ed memory so
threaded aps (with a default 64k stack) have a chance at working.
ok deraadt@

12 files changed, 348 insertions, 265 deletions

diff --git a/lib/libc/include/thread_private.h b/lib/libc/include/thread_private.h
index 0b0be6cb389..4212e7dcb2e 100644
--- a/lib/libc/include/thread_private.h
+++ b/lib/libc/include/thread_private.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: thread_private.h,v 1.14 2002/11/05 22:19:55 marc Exp $ */
+/* $OpenBSD: thread_private.h,v 1.15 2003/01/28 04:58:00 marc Exp $ */
 
 #ifndef _THREAD_PRIVATE_H_
 #define _THREAD_PRIVATE_H_
@@ -87,6 +87,15 @@ void *	_libc_private_storage(volatile struct _thread_private_key_struct *,
 			      &(storage), sizeof (storage), error)
 
 /*
+ * Keys used to access the per thread instances of resolver global data.
+ * These are not static as they are referenced in several places.
+ */
+extern volatile struct _thread_private_key_struct __THREAD_KEY_NAME(_res);
+#ifdef INET6
+extern volatile struct _thread_private_key_struct __THREAD_KEY_NAME(_res_ext);
+#endif
+
+/*
  * File descriptor locking definitions.
  */
 #define FD_READ		    0x1
diff --git a/lib/libc/net/getaddrinfo.c b/lib/libc/net/getaddrinfo.c
index 915286a404b..7406f107145 100644
--- a/lib/libc/net/getaddrinfo.c
+++ b/lib/libc/net/getaddrinfo.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: getaddrinfo.c,v 1.43 2002/08/27 08:53:13 itojun Exp $	*/
+/*	$OpenBSD: getaddrinfo.c,v 1.44 2003/01/28 04:58:00 marc Exp $	*/
 /*	$KAME: getaddrinfo.c,v 1.31 2000/08/31 17:36:43 itojun Exp $	*/
 
 /*
@@ -499,8 +499,6 @@ getaddrinfo(hostname, servname, hints, res)
  * FQDN hostname, DNS lookup
  */
 
-_THREAD_PRIVATE_MUTEX(getaddrinfo_explore_fqdn);
-
 static int
 explore_fqdn(pai, hostname, servname, res)
 	const struct addrinfo *pai;
@@ -508,13 +506,13 @@ explore_fqdn(pai, hostname, servname, res)
 	const char *servname;
 	struct addrinfo **res;
 {
+	struct __res_state *_resp = _THREAD_PRIVATE(_res, _res, &_res);
 	struct addrinfo *result;
 	struct addrinfo *cur;
 	int error = 0;
 	char lookups[MAXDNSLUS];
 	int i;
-
-	_THREAD_PRIVATE_MUTEX_LOCK(getaddrinfo_explore_fqdn);
+	_THREAD_PRIVATE_MUTEX(_explore_mutex);
 
 	result = NULL;
 
@@ -525,7 +523,6 @@ explore_fqdn(pai, hostname, servname, res)
 	 * XXX does not handle PF_UNSPEC case, should filter final result
 	 */
 	if ((pai->ai_flags & AI_ADDRCONFIG) != 0 && !addrconfig(pai)) {
-		_THREAD_PRIVATE_MUTEX_UNLOCK(getaddrinfo_explore_fqdn);
 		return 0;
 	}
 #endif
@@ -534,18 +531,22 @@ explore_fqdn(pai, hostname, servname, res)
 	 * if the servname does not match socktype/protocol, ignore it.
 	 */
 	if (get_portmatch(pai, servname) != 0) {
-		_THREAD_PRIVATE_MUTEX_UNLOCK(getaddrinfo_explore_fqdn);
 		return 0;
 	}
 
-	if ((_res.options & RES_INIT) == 0 && res_init() == -1)
+	if ((_resp->options & RES_INIT) == 0 && res_init() == -1)
 		strlcpy(lookups, "f", sizeof lookups);
 	else {
-		bcopy(_res.lookups, lookups, sizeof lookups);
+		bcopy(_resp->lookups, lookups, sizeof lookups);
 		if (lookups[0] == '\0')
 			strlcpy(lookups, "bf", sizeof lookups);
 	}
 
+	/*
+	 * The yp/dns/files getaddrinfo functions are not thread safe.
+	 * Protect them with a mutex.
+	 */
+	_THREAD_PRIVATE_MUTEX_LOCK(_explore_mutex);
 	for (i = 0; i < MAXDNSLUS && result == NULL && lookups[i]; i++) {
 		switch (lookups[i]) {
 #ifdef YP
@@ -561,13 +562,13 @@ explore_fqdn(pai, hostname, servname, res)
 			break;
 		}
 	}
+	_THREAD_PRIVATE_MUTEX_UNLOCK(_explore_mutex);
 	if (result) {
 		for (cur = result; cur; cur = cur->ai_next) {
 			GET_PORT(cur, servname);
 			/* canonname should be filled already */
 		}
 		*res = result;
-		_THREAD_PRIVATE_MUTEX_UNLOCK(getaddrinfo_explore_fqdn);
 		return 0;
 	} else {
 		/* translate error code */
@@ -599,7 +600,6 @@ explore_fqdn(pai, hostname, servname, res)
 free:
 	if (result)
 		freeaddrinfo(result);
-	_THREAD_PRIVATE_MUTEX_UNLOCK(getaddrinfo_explore_fqdn);
 	return error;
 }
 
@@ -867,6 +867,7 @@ get_port(ai, servname, matchonly)
 	struct servent *sp;
 	int port;
 	int allownumeric;
+	_THREAD_PRIVATE_MUTEX(serv_mutex);
 
 	if (servname == NULL)
 		return 0;
@@ -914,7 +915,10 @@ get_port(ai, servname, matchonly)
 			break;
 		}
 
-		if ((sp = getservbyname(servname, proto)) == NULL)
+		_THREAD_PRIVATE_MUTEX_LOCK(serv_mutex);
+		sp = getservbyname(servname, proto);
+		_THREAD_PRIVATE_MUTEX_UNLOCK(serv_mutex);
+		if (sp == NULL)
 			return EAI_SERVICE;
 		port = sp->s_port;
 	}
@@ -1563,18 +1567,26 @@ res_queryN(name, target)
 	const char *name;	/* domain name */
 	struct res_target *target;
 {
-	u_char buf[MAXPACKET];
+	struct __res_state *_resp = _THREAD_PRIVATE(_res, _res, &_res);
+	u_char *buf;
 	HEADER *hp;
 	int n;
 	struct res_target *t;
 	int rcode;
 	int ancount;
 
+	buf = malloc(MAXPACKET);
+	if (buf == NULL) {
+		h_errno = NETDB_INTERNAL;
+		return (-1);
+	}
+
 	rcode = NOERROR;
 	ancount = 0;
 
-	if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
+	if ((_resp->options & RES_INIT) == 0 && res_init() == -1) {
 		h_errno = NETDB_INTERNAL;
+		free(buf);
 		return (-1);
 	}
 
@@ -1592,30 +1604,32 @@ res_queryN(name, target)
 		answer = t->answer;
 		anslen = t->anslen;
 #ifdef DEBUG
-		if (_res.options & RES_DEBUG)
+		if (_resp->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 && (_res.options & RES_USE_EDNS0) != 0)
-			n = res_opt(n, buf, sizeof(buf), anslen);
+		    buf, MAXPACKET);
+		if (n > 0 && (_resp->options & RES_USE_EDNS0) != 0)
+			n = res_opt(n, buf, MAXPACKET, anslen);
 		if (n <= 0) {
 #ifdef DEBUG
-			if (_res.options & RES_DEBUG)
+			if (_resp->options & RES_DEBUG)
 				printf(";; res_query: mkquery failed\n");
 #endif
 			h_errno = NO_RECOVERY;
+			free(buf);
 			return (n);
 		}
 		n = res_send(buf, n, answer, anslen);
 #if 0
 		if (n < 0) {
 #ifdef DEBUG
-			if (_res.options & RES_DEBUG)
+			if (_resp->options & RES_DEBUG)
 				printf(";; res_query: send error\n");
 #endif
 			h_errno = TRY_AGAIN;
+			free(buf);
 			return (n);
 		}
 #endif
@@ -1623,7 +1637,7 @@ res_queryN(name, target)
 		if (n < 0 || hp->rcode != NOERROR || ntohs(hp->ancount) == 0) {
 			rcode = hp->rcode;	/* record most recent error */
 #ifdef DEBUG
-			if (_res.options & RES_DEBUG)
+			if (_resp->options & RES_DEBUG)
 				printf(";; rcode = %u, ancount=%u\n", hp->rcode,
 				    ntohs(hp->ancount));
 #endif
@@ -1653,8 +1667,10 @@ res_queryN(name, target)
 			h_errno = NO_RECOVERY;
 			break;
 		}
+		free(buf);
 		return (-1);
 	}
+	free(buf);
 	return (ancount);
 }
 
@@ -1669,13 +1685,14 @@ res_searchN(name, target)
 	const char *name;	/* domain name */
 	struct res_target *target;
 {
+	struct __res_state *_resp = _THREAD_PRIVATE(_res, _res, &_res);
 	const char *cp, * const *domain;
 	HEADER *hp = (HEADER *)(void *)target->answer;	/*XXX*/
 	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) {
+	if ((_resp->options & RES_INIT) == 0 && res_init() == -1) {
 		h_errno = NETDB_INTERNAL;
 		return (-1);
 	}
@@ -1700,7 +1717,7 @@ res_searchN(name, target)
 	 * 'as is'.  The threshold can be set with the "ndots" option.
 	 */
 	saved_herrno = -1;
-	if (dots >= _res.ndots) {
+	if (dots >= _resp->ndots) {
 		ret = res_querydomainN(name, NULL, target);
 		if (ret > 0)
 			return (ret);
@@ -1714,11 +1731,11 @@ res_searchN(name, target)
 	 *	- 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))) {
+	if ((!dots && (_resp->options & RES_DEFNAMES)) ||
+	    (dots && !trailing_dot && (_resp->options & RES_DNSRCH))) {
 		int done = 0;
 
-		for (domain = (const char * const *)_res.dnsrch;
+		for (domain = (const char * const *)_resp->dnsrch;
 		   *domain && !done;
 		   domain++) {
 
@@ -1766,7 +1783,7 @@ res_searchN(name, target)
 			 * 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))
+			if (!(_resp->options & RES_DNSRCH))
 			        done++;
 		}
 	}
@@ -1808,16 +1825,17 @@ res_querydomainN(name, domain, target)
 	const char *name, *domain;
 	struct res_target *target;
 {
+	struct __res_state *_resp = _THREAD_PRIVATE(_res, _res, &_res);
 	char nbuf[MAXDNAME];
 	const char *longname = nbuf;
 	size_t n, d;
 
-	if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
+	if ((_resp->options & RES_INIT) == 0 && res_init() == -1) {
 		h_errno = NETDB_INTERNAL;
 		return (-1);
 	}
 #ifdef DEBUG
-	if (_res.options & RES_DEBUG)
+	if (_resp->options & RES_DEBUG)
 		printf(";; res_querydomain(%s, %s)\n",
 			name, domain?domain:"<Nil>");
 #endif
diff --git a/lib/libc/net/gethostnamadr.c b/lib/libc/net/gethostnamadr.c
index 909ce573b73..5211f423c60 100644
--- a/lib/libc/net/gethostnamadr.c
+++ b/lib/libc/net/gethostnamadr.c
@@ -52,7 +52,7 @@
  */
 
 #if defined(LIBC_SCCS) && !defined(lint)
-static char rcsid[] = "$OpenBSD: gethostnamadr.c,v 1.53 2002/08/27 08:53:13 itojun Exp $";
+static char rcsid[] = "$OpenBSD: gethostnamadr.c,v 1.54 2003/01/28 04:58:00 marc Exp $";
 #endif /* LIBC_SCCS and not lint */
 
 #include <sys/param.h>
@@ -160,6 +160,7 @@ getanswer(answer, anslen, qname, qtype)
 	const char *qname;
 	int qtype;
 {
+	struct __res_state *_resp = _THREAD_PRIVATE(_res, _res, &_res);
 	register const HEADER *hp;
 	register const u_char *cp;
 	register int n;
@@ -339,7 +340,7 @@ getanswer(answer, anslen, qname, qtype)
 			break;
 #else
 			host.h_name = bp;
-			if (_res.options & RES_USE_INET6) {
+			if (_resp->options & RES_USE_INET6) {
 				n = strlen(bp) + 1;	/* for the \0 */
 				bp += n;
 				map_v4v6_hostent(&host, &bp, ep);
@@ -379,7 +380,7 @@ getanswer(answer, anslen, qname, qtype)
 
 			if (bp + n >= &hostbuf[sizeof hostbuf]) {
 #ifdef DEBUG
-				if (_res.options & RES_DEBUG)
+				if (_resp->options & RES_DEBUG)
 					printf("size (%d) too big\n", n);
 #endif
 				had_error++;
@@ -388,7 +389,7 @@ getanswer(answer, anslen, qname, qtype)
 			if (hap >= &h_addr_ptrs[MAXADDRS-1]) {
 				if (!toobig++)
 #ifdef DEBUG
-					if (_res.options & RES_DEBUG)
+					if (_resp->options & RES_DEBUG)
 						printf("Too many addresses (%d)\n", MAXADDRS);
 #endif
 				cp += n;
@@ -411,7 +412,7 @@ getanswer(answer, anslen, qname, qtype)
 		 * in its return structures - should give it the "best"
 		 * address in that case, not some random one
 		 */
-		if (_res.nsort && haveanswer > 1 && qtype == T_A)
+		if (_resp->nsort && haveanswer > 1 && qtype == T_A)
 			addrsort(h_addr_ptrs, haveanswer);
 # endif /*RESOLVSORT*/
 		if (!host.h_name) {
@@ -422,7 +423,7 @@ getanswer(answer, anslen, qname, qtype)
 			host.h_name = bp;
 			bp += n;
 		}
-		if (_res.options & RES_USE_INET6)
+		if (_resp->options & RES_USE_INET6)
 			map_v4v6_hostent(&host, &bp, ep);
 		h_errno = NETDB_SUCCESS;
 		return (&host);
@@ -484,27 +485,24 @@ gethostbyaddr_r(addr, len, af, he, buf, buflen, errorp)
 /* XXX RFC2133 expects a gethostbyname2_r() -- unimplemented */
 #endif
 
-_THREAD_PRIVATE_MUTEX(gethostnamadr);
-
 struct hostent *
 gethostbyname(name)
 	const char *name;
 {
+	struct __res_state *_resp = _THREAD_PRIVATE(_res, _res, &_res);
 	struct hostent *hp;
 	extern struct hostent *_gethtbyname2();
 
-	_THREAD_PRIVATE_MUTEX_LOCK(gethostnamadr);
-	if ((_res.options & RES_INIT) == 0 && res_init() == -1)
+	if ((_resp->options & RES_INIT) == 0 && res_init() == -1)
 		hp = _gethtbyname2(name, AF_INET);
 
-	else if (_res.options & RES_USE_INET6) {
+	else if (_resp->options & RES_USE_INET6) {
 		hp = gethostbyname2(name, AF_INET6);
 		if (hp == NULL)
 			hp = gethostbyname2(name, AF_INET);
 	}
 	else
 		hp = gethostbyname2(name, AF_INET);
-	_THREAD_PRIVATE_MUTEX_UNLOCK(gethostnamadr);
 	return hp;
 }
 
@@ -513,6 +511,7 @@ gethostbyname2(name, af)
 	const char *name;
 	int af;
 {
+	struct __res_state *_resp = _THREAD_PRIVATE(_res, _res, &_res);
 	querybuf *buf;
 	register const char *cp;
 	char *bp, *ep;
@@ -521,7 +520,7 @@ gethostbyname2(name, af)
 	register struct hostent *hp;
 	char lookups[MAXDNSLUS];
 
-	if ((_res.options & RES_INIT) == 0 && res_init() == -1)
+	if ((_resp->options & RES_INIT) == 0 && res_init() == -1)
 		return (_gethtbyname2(name, af));
 
 	switch (af) {
@@ -577,7 +576,7 @@ gethostbyname2(name, af)
 				h_addr_ptrs[0] = (char *)host_addr;
 				h_addr_ptrs[1] = NULL;
 				host.h_addr_list = h_addr_ptrs;
-				if (_res.options & RES_USE_INET6)
+				if (_resp->options & RES_USE_INET6)
 					map_v4v6_hostent(&host, &bp, ep);
 				h_errno = NETDB_SUCCESS;
 				return (&host);
@@ -616,7 +615,7 @@ gethostbyname2(name, af)
 				break;
 		}
 
-	bcopy(_res.lookups, lookups, sizeof lookups);
+	bcopy(_resp->lookups, lookups, sizeof lookups);
 	if (lookups[0] == '\0')
 		strlcpy(lookups, "bf", sizeof lookups);
 
@@ -638,7 +637,7 @@ gethostbyname2(name, af)
 			    sizeof(buf->buf))) < 0) {
 				free(buf);
 #ifdef DEBUG
-				if (_res.options & RES_DEBUG)
+				if (_resp->options & RES_DEBUG)
 					printf("res_search failed\n");
 #endif
 				break;
@@ -660,6 +659,7 @@ gethostbyaddr(addr, len, af)
 	const char *addr;	/* XXX should have been def'd as u_char! */
 	int len, af;
 {
+	struct __res_state *_resp = _THREAD_PRIVATE(_res, _res, &_res);
 	const u_char *uaddr = (const u_char *)addr;
 	int n, size, i;
 	querybuf *buf;
@@ -669,10 +669,8 @@ gethostbyaddr(addr, len, af)
 	char lookups[MAXDNSLUS];
 	struct hostent *res;
 	
-	_THREAD_PRIVATE_MUTEX_LOCK(gethostnamadr);
-	if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
+	if ((_resp->options & RES_INIT) == 0 && res_init() == -1) {
 		res = _gethtbyaddr(addr, len, af);
-		_THREAD_PRIVATE_MUTEX_UNLOCK(gethostnamadr);
 		return (res);
 	}
 
@@ -701,13 +699,11 @@ gethostbyaddr(addr, len, af)
 	default:
 		errno = EAFNOSUPPORT;
 		h_errno = NETDB_INTERNAL;
-		_THREAD_PRIVATE_MUTEX_UNLOCK(gethostnamadr);
 		return (NULL);
 	}
 	if (size != len) {
 		errno = EINVAL;
 		h_errno = NETDB_INTERNAL;
-		_THREAD_PRIVATE_MUTEX_UNLOCK(gethostnamadr);
 		return (NULL);
 	}
 	switch (af) {
@@ -725,7 +721,7 @@ gethostbyaddr(addr, len, af)
 		break;
 	}
 
-	bcopy(_res.lookups, lookups, sizeof lookups);
+	bcopy(_resp->lookups, lookups, sizeof lookups);
 	if (lookups[0] == '\0')
 		strlcpy(lookups, "bf", sizeof lookups);
 
@@ -755,7 +751,7 @@ gethostbyaddr(addr, len, af)
 			if (n < 0) {
 				free(buf);
 #ifdef DEBUG
-				if (_res.options & RES_DEBUG)
+				if (_resp->options & RES_DEBUG)
 					printf("res_query failed\n");
 #endif
 				break;
@@ -770,7 +766,7 @@ gethostbyaddr(addr, len, af)
 			bcopy(addr, host_addr, len);
 			h_addr_ptrs[0] = (char *)host_addr;
 			h_addr_ptrs[1] = NULL;
-			if (af == AF_INET && (_res.options & RES_USE_INET6)) {
+			if (af == AF_INET && (_resp->options & RES_USE_INET6)) {
 				map_v4v6_address((char*)host_addr,
 				    (char*)host_addr);
 				hp->h_addrtype = AF_INET6;
@@ -783,7 +779,6 @@ gethostbyaddr(addr, len, af)
 			break;
 		}
 	}
-	_THREAD_PRIVATE_MUTEX_UNLOCK(gethostnamadr);
 	/* XXX h_errno not correct in all cases... */
 	return (hp);
 }
@@ -811,6 +806,7 @@ _endhtent()
 struct hostent *
 _gethtent()
 {
+	struct __res_state *_resp = _THREAD_PRIVATE(_res, _res, &_res);
 	char *p;
 	register char *cp, **q;
 	int af;
@@ -842,7 +838,7 @@ _gethtent()
 		af = AF_INET6;
 		len = IN6ADDRSZ;
 	} else if (inet_pton(AF_INET, p, host_addr) > 0) {
-		if (_res.options & RES_USE_INET6) {
+		if (_resp->options & RES_USE_INET6) {
 			map_v4v6_address((char*)host_addr, (char*)host_addr);
 			af = AF_INET6;
 			len = IN6ADDRSZ;
@@ -880,7 +876,7 @@ _gethtent()
 			*cp++ = '\0';
 	}
 	*q = NULL;
-	if (_res.options & RES_USE_INET6) {
+	if (_resp->options & RES_USE_INET6) {
 		char *bp = hostbuf;
 		char *ep = hostbuf + sizeof hostbuf;
 
@@ -894,10 +890,11 @@ struct hostent *
 _gethtbyname(name)
 	const char *name;
 {
+	struct __res_state *_resp = _THREAD_PRIVATE(_res, _res, &_res);
 	extern struct hostent *_gethtbyname2();
 	struct hostent *hp;
 
-	if (_res.options & RES_USE_INET6) {
+	if (_resp->options & RES_USE_INET6) {
 		hp = _gethtbyname2(name, AF_INET6);
 		if (hp)
 			return (hp);
@@ -1136,6 +1133,7 @@ addrsort(ap, num)
 	char **ap;
 	int num;
 {
+	struct __res_state *_resp = _THREAD_PRIVATE(_res, _res, &_res);
 	int i, j;
 	char **p;
 	short aval[MAXADDRS];
@@ -1143,9 +1141,9 @@ addrsort(ap, num)
 
 	p = ap;
 	for (i = 0; i < num; i++, p++) {
-		for (j = 0 ; (unsigned)j < _res.nsort; j++)
-			if (_res.sort_list[j].addr.s_addr == 
-			    (((struct in_addr *)(*p))->s_addr & _res.sort_list[j].mask))
+		for (j = 0 ; (unsigned)j < _resp->nsort; j++)
+			if (_resp->sort_list[j].addr.s_addr == 
+			    (((struct in_addr *)(*p))->s_addr & _resp->sort_list[j].mask))
 				break;
 		aval[i] = j;
 		if (needsort == 0 && i > 0 && j < aval[i-1])
diff --git a/lib/libc/net/getnameinfo.c b/lib/libc/net/getnameinfo.c
index 2311eba7a02..d3a9678cbd6 100644
--- a/lib/libc/net/getnameinfo.c
+++ b/lib/libc/net/getnameinfo.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: getnameinfo.c,v 1.25 2002/06/27 09:24:28 itojun Exp $	*/
+/*	$OpenBSD: getnameinfo.c,v 1.26 2003/01/28 04:58:00 marc Exp $	*/
 /*	$KAME: getnameinfo.c,v 1.45 2000/09/25 22:43:56 itojun Exp $	*/
 
 /*
@@ -59,6 +59,8 @@
 #include <string.h>
 #include <stddef.h>
 
+#include "thread_private.h"
+
 static const struct afd {
 	int a_af;
 	int a_addrlen;
@@ -106,6 +108,7 @@ getnameinfo(sa, salen, host, hostlen, serv, servlen, flags)
 	int h_error;
 	char numserv[512];
 	char numaddr[512];
+	_THREAD_PRIVATE_MUTEX(serv_mutex);
 
 	if (sa == NULL)
 		return EAI_FAIL;
@@ -140,8 +143,10 @@ getnameinfo(sa, salen, host, hostlen, serv, servlen, flags)
 		if (flags & NI_NUMERICSERV)
 			sp = NULL;
 		else {
+			_THREAD_PRIVATE_MUTEX_LOCK(serv_mutex);
 			sp = getservbyport(port,
 			    (flags & NI_DGRAM) ? "udp" : "tcp");
+			_THREAD_PRIVATE_MUTEX_UNLOCK(serv_mutex);
 		}
 		if (sp) {
 			if (strlen(sp->s_name) + 1 > servlen)
@@ -228,7 +233,9 @@ getnameinfo(sa, salen, host, hostlen, serv, servlen, flags)
 			break;
 		}
 	} else {
+		_THREAD_PRIVATE_MUTEX_LOCK(serv_mutex);
 		hp = gethostbyaddr(addr, afd->a_addrlen, afd->a_af);
+		_THREAD_PRIVATE_MUTEX_UNLOCK(serv_mutex);
 		h_error = h_errno;
 
 		if (hp) {
diff --git a/lib/libc/net/getnetnamadr.c b/lib/libc/net/getnetnamadr.c
index f183fbe3fef..75a75243efd 100644
--- a/lib/libc/net/getnetnamadr.c
+++ b/lib/libc/net/getnetnamadr.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: getnetnamadr.c,v 1.19 2002/11/14 02:48:00 millert Exp $	*/
+/*	$OpenBSD: getnetnamadr.c,v 1.20 2003/01/28 04:58:00 marc Exp $	*/
 
 /*
  * Copyright (c) 1997, Jason Downs.  All rights reserved.
@@ -77,7 +77,7 @@ static char sccsid[] = "@(#)getnetbyaddr.c	8.1 (Berkeley) 6/4/93";
 static char sccsid_[] = "from getnetnamadr.c	1.4 (Coimbra) 93/06/03";
 static char rcsid[] = "$From: getnetnamadr.c,v 8.7 1996/08/05 08:31:35 vixie Exp $";
 #else
-static char rcsid[] = "$OpenBSD: getnetnamadr.c,v 1.19 2002/11/14 02:48:00 millert Exp $";
+static char rcsid[] = "$OpenBSD: getnetnamadr.c,v 1.20 2003/01/28 04:58:00 marc Exp $";
 #endif
 #endif /* LIBC_SCCS and not lint */
 
@@ -96,6 +96,8 @@ static char rcsid[] = "$OpenBSD: getnetnamadr.c,v 1.19 2002/11/14 02:48:00 mille
 #include <string.h>
 #include <stdlib.h>
 
+#include "thread_private.h"
+
 extern int h_errno;
 
 struct netent *_getnetbyaddr(in_addr_t net, int type);
@@ -262,6 +264,7 @@ getnetbyaddr(net, net_type)
 	register in_addr_t net;
 	register int net_type;
 {
+	struct __res_state *_resp = _THREAD_PRIVATE(_res, _res, &_res);
 	unsigned int netbr[4];
 	int nn, anslen;
 	querybuf *buf;
@@ -271,10 +274,10 @@ getnetbyaddr(net, net_type)
 	char lookups[MAXDNSLUS];
 	int i;
 
-	if ((_res.options & RES_INIT) == 0 && res_init() == -1)
+	if ((_resp->options & RES_INIT) == 0 && res_init() == -1)
 		return(_getnetbyaddr(net, net_type));
 
-	bcopy(_res.lookups, lookups, sizeof lookups);
+	bcopy(_resp->lookups, lookups, sizeof lookups);
 	if (lookups[0] == '\0')
 		strlcpy(lookups, "bf", sizeof lookups);
 
@@ -320,7 +323,7 @@ getnetbyaddr(net, net_type)
 			if (anslen < 0) {
 				free(buf);
 #ifdef DEBUG
-				if (_res.options & RES_DEBUG)
+				if (_resp->options & RES_DEBUG)
 					printf("res_query failed\n");
 #endif
 				break;
@@ -352,6 +355,7 @@ struct netent *
 getnetbyname(net)
 	register const char *net;
 {
+	struct __res_state *_resp = _THREAD_PRIVATE(_res, _res, &_res);
 	int anslen;
 	querybuf *buf;
 	char qbuf[MAXDNAME];
@@ -359,10 +363,10 @@ getnetbyname(net)
 	char lookups[MAXDNSLUS];
 	int i;
 
-	if ((_res.options & RES_INIT) == 0 && res_init() == -1)
+	if ((_resp->options & RES_INIT) == 0 && res_init() == -1)
 		return (_getnetbyname(net));
 
-	bcopy(_res.lookups, lookups, sizeof lookups);
+	bcopy(_resp->lookups, lookups, sizeof lookups);
 	if (lookups[0] == '\0')
 		strlcpy(lookups, "bf", sizeof lookups);
 
@@ -383,7 +387,7 @@ getnetbyname(net)
 			if (anslen < 0) {
 				free(buf);
 #ifdef DEBUG
-				if (_res.options & RES_DEBUG)
+				if (_resp->options & RES_DEBUG)
 					printf("res_query failed\n");
 #endif
 				break;
diff --git a/lib/libc/net/getrrsetbyname.c b/lib/libc/net/getrrsetbyname.c
index 1ec60486b3d..e4bd9a936ec 100644
--- a/lib/libc/net/getrrsetbyname.c
+++ b/lib/libc/net/getrrsetbyname.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: getrrsetbyname.c,v 1.5 2002/09/07 20:54:04 jakob Exp $ */
+/* $OpenBSD: getrrsetbyname.c,v 1.6 2003/01/28 04:58:00 marc Exp $ */
 
 /*
  * Copyright (c) 2001 Jakob Schlyter. All rights reserved.
@@ -51,6 +51,8 @@
 #include <stdlib.h>
 #include <string.h>
 
+#include "thread_private.h"
+
 #define ANSWER_BUFFER_SIZE 1024*64
 
 struct dns_query {
@@ -95,6 +97,7 @@ getrrsetbyname(const char *hostname, unsigned int rdclass,
     unsigned int rdtype, unsigned int flags,
     struct rrsetinfo **res)
 {
+	struct __res_state *_resp = _THREAD_PRIVATE(_res, _res, &_res);
 	int result;
 	struct rrsetinfo *rrset = NULL;
 	struct dns_response *response;
@@ -122,19 +125,19 @@ getrrsetbyname(const char *hostname, unsigned int rdclass,
 	}
 
 	/* initialize resolver */
-	if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
+	if ((_resp->options & RES_INIT) == 0 && res_init() == -1) {
 		result = ERRSET_FAIL;
 		goto fail;
 	}
 
 #ifdef DEBUG
-	_res.options |= RES_DEBUG;
+	_resp->options |= RES_DEBUG;
 #endif /* DEBUG */
 
 #ifdef RES_USE_DNSSEC
 	/* turn on DNSSEC if EDNS0 is configured */
-	if (_res.options & RES_USE_EDNS0)
-		_res.options |= RES_USE_DNSSEC;
+	if (_resp->options & RES_USE_EDNS0)
+		_resp->options |= RES_USE_DNSSEC;
 #endif /* RES_USE_DNSEC */
 
 	/* make query */
diff --git a/lib/libc/net/res_debug.c b/lib/libc/net/res_debug.c
index 2ea9173fe90..f4e4c271ed2 100644
--- a/lib/libc/net/res_debug.c
+++ b/lib/libc/net/res_debug.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: res_debug.c,v 1.14 2002/07/25 21:55:30 deraadt Exp $	*/
+/*	$OpenBSD: res_debug.c,v 1.15 2003/01/28 04:58:00 marc Exp $	*/
 
 /*
  * ++Copyright++ 1985, 1990, 1993
@@ -82,7 +82,7 @@
 static char sccsid[] = "@(#)res_debug.c	8.1 (Berkeley) 6/4/93";
 static char rcsid[] = "$From: res_debug.c,v 8.19 1996/11/26 10:11:23 vixie Exp $";
 #else
-static char rcsid[] = "$OpenBSD: res_debug.c,v 1.14 2002/07/25 21:55:30 deraadt Exp $";
+static char rcsid[] = "$OpenBSD: res_debug.c,v 1.15 2003/01/28 04:58:00 marc Exp $";
 #endif
 #endif /* LIBC_SCCS and not lint */
 
@@ -102,6 +102,8 @@ static char rcsid[] = "$OpenBSD: res_debug.c,v 1.14 2002/07/25 21:55:30 deraadt
 #include <stdlib.h>
 #include <string.h>
 
+#include "thread_private.h"
+
 extern const char *_res_opcodes[];
 extern const char *_res_resultcodes[];
 
@@ -200,19 +202,20 @@ do_rrset(msg, len, cp, cnt, pflag, file, hs)
 	const char *hs;
 	FILE *file;
 {
+	struct __res_state *_resp = _THREAD_PRIVATE(_res, _res, &_res);
 	int n;
 	int sflag;
 
 	/*
 	 * Print answer records.
 	 */
-	sflag = (_res.pfcode & pflag);
+	sflag = (_resp->pfcode & pflag);
 	if ((n = ntohs(cnt))) {
-		if ((!_res.pfcode) ||
-		    ((sflag) && (_res.pfcode & RES_PRF_HEAD1)))
+		if ((!_resp->pfcode) ||
+		    ((sflag) && (_resp->pfcode & RES_PRF_HEAD1)))
 			fprintf(file, "%s", hs);
 		while (--n >= 0) {
-			if ((!_res.pfcode) || sflag) {
+			if ((!_resp->pfcode) || sflag) {
 				cp = p_rr(cp, msg, file);
 			} else {
 				unsigned int dlen;
@@ -227,8 +230,8 @@ do_rrset(msg, len, cp, cnt, pflag, file, hs)
 			if ((cp - msg) > len)
 				return (NULL);
 		}
-		if ((!_res.pfcode) ||
-		    ((sflag) && (_res.pfcode & RES_PRF_HEAD1)))
+		if ((!_resp->pfcode) ||
+		    ((sflag) && (_resp->pfcode & RES_PRF_HEAD1)))
 			putc('\n', file);
 	}
 	return (cp);
@@ -271,11 +274,12 @@ __fp_nquery(msg, len, file)
 	int len;
 	FILE *file;
 {
+	struct __res_state *_resp = _THREAD_PRIVATE(_res, _res, &_res);
 	register const u_char *cp, *endMark;
 	register const HEADER *hp;
 	register int n;
 
-	if ((_res.options & RES_INIT) == 0 && res_init() == -1)
+	if ((_resp->options & RES_INIT) == 0 && res_init() == -1)
 		return;
 
 #define TruncTest(x) if (x > endMark) goto trunc
@@ -287,16 +291,16 @@ __fp_nquery(msg, len, file)
 	hp = (HEADER *)msg;
 	cp = msg + HFIXEDSZ;
 	endMark = msg + len;
-	if ((!_res.pfcode) || (_res.pfcode & RES_PRF_HEADX) || hp->rcode) {
+	if ((!_resp->pfcode) || (_resp->pfcode & RES_PRF_HEADX) || hp->rcode) {
 		fprintf(file, ";; ->>HEADER<<- opcode: %s, status: %s, id: %u",
 			_res_opcodes[hp->opcode],
 			_res_resultcodes[hp->rcode],
 			ntohs(hp->id));
 		putc('\n', file);
 	}
-	if ((!_res.pfcode) || (_res.pfcode & RES_PRF_HEADX))
+	if ((!_resp->pfcode) || (_resp->pfcode & RES_PRF_HEADX))
 		putc(';', file);
-	if ((!_res.pfcode) || (_res.pfcode & RES_PRF_HEAD2)) {
+	if ((!_resp->pfcode) || (_resp->pfcode & RES_PRF_HEAD2)) {
 		fprintf(file, "; flags:");
 		if (hp->qr)
 			fprintf(file, " qr");
@@ -315,13 +319,13 @@ __fp_nquery(msg, len, file)
 		if (hp->cd)
 			fprintf(file, " cd");
 	}
-	if ((!_res.pfcode) || (_res.pfcode & RES_PRF_HEAD1)) {
+	if ((!_resp->pfcode) || (_resp->pfcode & RES_PRF_HEAD1)) {
 		fprintf(file, "; Ques: %u", ntohs(hp->qdcount));
 		fprintf(file, ", Ans: %u", ntohs(hp->ancount));
 		fprintf(file, ", Auth: %u", ntohs(hp->nscount));
 		fprintf(file, ", Addit: %u", ntohs(hp->arcount));
 	}
-	if ((!_res.pfcode) || (_res.pfcode & 
+	if ((!_resp->pfcode) || (_resp->pfcode & 
 		(RES_PRF_HEADX | RES_PRF_HEAD2 | RES_PRF_HEAD1))) {
 		putc('\n',file);
 	}
@@ -329,13 +333,13 @@ __fp_nquery(msg, len, file)
 	 * Print question records.
 	 */
 	if ((n = ntohs(hp->qdcount))) {
-		if ((!_res.pfcode) || (_res.pfcode & RES_PRF_QUES))
+		if ((!_resp->pfcode) || (_resp->pfcode & RES_PRF_QUES))
 			fprintf(file, ";; QUESTIONS:\n");
 		while (--n >= 0) {
-			if ((!_res.pfcode) || (_res.pfcode & RES_PRF_QUES))
+			if ((!_resp->pfcode) || (_resp->pfcode & RES_PRF_QUES))
 				fprintf(file, ";;\t");
 			TruncTest(cp);
-			if ((!_res.pfcode) || (_res.pfcode & RES_PRF_QUES))
+			if ((!_resp->pfcode) || (_resp->pfcode & RES_PRF_QUES))
 				cp = p_cdnname(cp, msg, len, file);
 			else {
 				int n;
@@ -349,16 +353,16 @@ __fp_nquery(msg, len, file)
 			}
 			ErrorTest(cp);
 			TruncTest(cp);
-			if ((!_res.pfcode) || (_res.pfcode & RES_PRF_QUES))
+			if ((!_resp->pfcode) || (_resp->pfcode & RES_PRF_QUES))
 				fprintf(file, ", type = %s",
 					__p_type(_getshort((u_char*)cp)));
 			cp += INT16SZ;
 			TruncTest(cp);
-			if ((!_res.pfcode) || (_res.pfcode & RES_PRF_QUES))
+			if ((!_resp->pfcode) || (_resp->pfcode & RES_PRF_QUES))
 				fprintf(file, ", class = %s\n",
 					__p_class(_getshort((u_char*)cp)));
 			cp += INT16SZ;
-			if ((!_res.pfcode) || (_res.pfcode & RES_PRF_QUES))
+			if ((!_resp->pfcode) || (_resp->pfcode & RES_PRF_QUES))
 				putc('\n', file);
 		}
 	}
@@ -478,6 +482,7 @@ __p_rr(cp, msg, file)
 	const u_char *cp, *msg;
 	FILE *file;
 {
+	struct __res_state *_resp = _THREAD_PRIVATE(_res, _res, &_res);
 	int type, class, dlen, n, c;
 	struct in_addr inaddr;
 	const u_char *cp1, *cp2;
@@ -487,7 +492,7 @@ __p_rr(cp, msg, file)
 	char rrname[MAXDNAME];		/* The fqdn of this RR */
 	char base64_key[MAX_KEY_BASE64];
 
-	if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
+	if ((_resp->options & RES_INIT) == 0 && res_init() == -1) {
 		h_errno = NETDB_INTERNAL;
 		return (NULL);
 	}
@@ -505,9 +510,9 @@ __p_rr(cp, msg, file)
 	dlen = _getshort((u_char*)cp);
 	cp += INT16SZ;
 	cp1 = cp;
-	if ((!_res.pfcode) || (_res.pfcode & RES_PRF_TTLID))
+	if ((!_resp->pfcode) || (_resp->pfcode & RES_PRF_TTLID))
 		fprintf(file, "\t%lu", (u_long)tmpttl);
-	if ((!_res.pfcode) || (_res.pfcode & RES_PRF_CLASS))
+	if ((!_resp->pfcode) || (_resp->pfcode & RES_PRF_CLASS))
 		fprintf(file, "\t%s", __p_class(class));
 	fprintf(file, "\t%s", __p_type(type));
 	/*
diff --git a/lib/libc/net/res_init.c b/lib/libc/net/res_init.c
index c55c7763a4e..a1d69f57b5e 100644
--- a/lib/libc/net/res_init.c
+++ b/lib/libc/net/res_init.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: res_init.c,v 1.27 2002/07/25 21:13:45 deraadt Exp $	*/
+/*	$OpenBSD: res_init.c,v 1.28 2003/01/28 04:58:00 marc Exp $	*/
 
 /*
  * ++Copyright++ 1985, 1989, 1993
@@ -64,7 +64,7 @@
 static char sccsid[] = "@(#)res_init.c	8.1 (Berkeley) 6/7/93";
 static char rcsid[] = "$From: res_init.c,v 8.7 1996/09/28 06:51:07 vixie Exp $";
 #else
-static char rcsid[] = "$OpenBSD: res_init.c,v 1.27 2002/07/25 21:13:45 deraadt Exp $";
+static char rcsid[] = "$OpenBSD: res_init.c,v 1.28 2003/01/28 04:58:00 marc Exp $";
 #endif
 #endif /* LIBC_SCCS and not lint */
 
@@ -86,6 +86,8 @@ static char rcsid[] = "$OpenBSD: res_init.c,v 1.27 2002/07/25 21:13:45 deraadt E
 #include <netdb.h>
 #endif /* INET6 */
 
+#include "thread_private.h"
+
 /*-------------------------------------- info about "sortlist" --------------
  * Marc Majka		1994/04/16
  * Allan Nathanson	1994/10/29 (BIND 4.9.3.x)
@@ -120,6 +122,9 @@ static u_int32_t net_mask(struct in_addr);
 /*
  * Resolver state default settings.
  */
+volatile struct _thread_private_key_struct __THREAD_KEY_NAME(_res) = {
+	PTHREAD_ONCE_INIT, 0
+};
 
 struct __res_state _res
 # if defined(__BIND_RES_TEXT)
@@ -127,6 +132,10 @@ struct __res_state _res
 # endif
 	;
 #ifdef INET6
+volatile struct _thread_private_key_struct __THREAD_KEY_NAME(_res_ext) = {
+	PTHREAD_ONCE_INIT, 0
+};
+
 struct __res_state_ext _res_ext;
 #endif /* INET6 */
 
@@ -154,6 +163,11 @@ struct __res_state_ext _res_ext;
 int
 res_init()
 {
+	struct __res_state *_resp = _THREAD_PRIVATE(_res, _res, &_res);
+#ifdef INET6
+	struct __res_state_ext *_res_extp = _THREAD_PRIVATE(_res_ext, _res_ext,
+							    &_res_ext);
+#endif
 	register FILE *fp;
 	register char *cp, **pp;
 	register int n;
@@ -189,33 +203,33 @@ res_init()
 	 * set in RES_DEFAULT).  Our solution is to declare such applications
 	 * "broken".  They could fool us by setting RES_INIT but none do (yet).
 	 */
-	if (!_res.retrans)
-		_res.retrans = RES_TIMEOUT;
-	if (!_res.retry)
-		_res.retry = 4;
-	if (!(_res.options & RES_INIT))
-		_res.options = RES_DEFAULT;
+	if (!_resp->retrans)
+		_resp->retrans = RES_TIMEOUT;
+	if (!_resp->retry)
+		_resp->retry = 4;
+	if (!(_resp->options & RES_INIT))
+		_resp->options = RES_DEFAULT;
 
 #ifdef USELOOPBACK
-	_res.nsaddr.sin_addr = inet_makeaddr(IN_LOOPBACKNET, 1);
+	_resp->nsaddr.sin_addr = inet_makeaddr(IN_LOOPBACKNET, 1);
 #else
-	_res.nsaddr.sin_addr.s_addr = INADDR_ANY;
+	_resp->nsaddr.sin_addr.s_addr = INADDR_ANY;
 #endif
-	_res.nsaddr.sin_family = AF_INET;
-	_res.nsaddr.sin_port = htons(NAMESERVER_PORT);
-	_res.nsaddr.sin_len = sizeof(struct sockaddr_in);
+	_resp->nsaddr.sin_family = AF_INET;
+	_resp->nsaddr.sin_port = htons(NAMESERVER_PORT);
+	_resp->nsaddr.sin_len = sizeof(struct sockaddr_in);
 #ifdef INET6
-	if (sizeof(_res_ext.nsaddr) >= _res.nsaddr.sin_len)
-		memcpy(&_res_ext.nsaddr, &_res.nsaddr, _res.nsaddr.sin_len);
+	if (sizeof(_res_extp->nsaddr) >= _resp->nsaddr.sin_len)
+		memcpy(&_res_extp->nsaddr, &_resp->nsaddr, _resp->nsaddr.sin_len);
 #endif
-	_res.nscount = 1;
-	_res.ndots = 1;
-	_res.pfcode = 0;
-	strlcpy(_res.lookups, "f", sizeof _res.lookups);
+	_resp->nscount = 1;
+	_resp->ndots = 1;
+	_resp->pfcode = 0;
+	strlcpy(_resp->lookups, "f", sizeof _resp->lookups);
 
 	/* Allow user to override the local domain definition */
 	if (issetugid() == 0 && (cp = getenv("LOCALDOMAIN")) != NULL) {
-		strlcpy(_res.defdname, cp, sizeof(_res.defdname));
+		strlcpy(_resp->defdname, cp, sizeof(_resp->defdname));
 		haveenv++;
 
 		/*
@@ -225,10 +239,10 @@ res_init()
 		 * one that they want to use as an individual (even more
 		 * important now that the rfc1535 stuff restricts searches)
 		 */
-		cp = _res.defdname;
-		pp = _res.dnsrch;
+		cp = _resp->defdname;
+		pp = _resp->dnsrch;
 		*pp++ = cp;
-		for (n = 0; *cp && pp < _res.dnsrch + MAXDNSRCH; cp++) {
+		for (n = 0; *cp && pp < _resp->dnsrch + MAXDNSRCH; cp++) {
 			if (*cp == '\n')	/* silly backwards compat */
 				break;
 			else if (*cp == ' ' || *cp == '\t') {
@@ -253,7 +267,7 @@ res_init()
 	 line[sizeof(name) - 1] == '\t'))
 
 	if ((fp = fopen(_PATH_RESCONF, "r")) != NULL) {
-	    strlcpy(_res.lookups, "bf", sizeof _res.lookups);
+	    strlcpy(_resp->lookups, "bf", sizeof _resp->lookups);
 
 	    /* read the config file */
 	    buf[0] = '\0';
@@ -277,8 +291,8 @@ res_init()
 			    cp++;
 		    if ((*cp == '\0') || (*cp == '\n'))
 			    continue;
-		    strlcpy(_res.defdname, cp, sizeof(_res.defdname));
-		    if ((cp = strpbrk(_res.defdname, " \t\n")) != NULL)
+		    strlcpy(_resp->defdname, cp, sizeof(_resp->defdname));
+		    if ((cp = strpbrk(_resp->defdname, " \t\n")) != NULL)
 			    *cp = '\0';
 		    havesearch = 0;
 		    continue;
@@ -287,7 +301,7 @@ res_init()
 		if (MATCH(buf, "lookup")) {
 		    char *sp = NULL;
 
-		    bzero(_res.lookups, sizeof _res.lookups);
+		    bzero(_resp->lookups, sizeof _resp->lookups);
 		    cp = buf + sizeof("lookup") - 1;
 		    for (n = 0;; cp++) {
 		    	    if (n == MAXDNSLUS)
@@ -295,14 +309,14 @@ res_init()
 			    if ((*cp == '\0') || (*cp == '\n')) {
 				    if (sp) {
 					    if (*sp=='y' || *sp=='b' || *sp=='f')
-						    _res.lookups[n++] = *sp;
+						    _resp->lookups[n++] = *sp;
 					    sp = NULL;
 				    }
 				    break;
 			    } else if ((*cp == ' ') || (*cp == '\t') || (*cp == ',')) {
 				    if (sp) {
 					    if (*sp=='y' || *sp=='b' || *sp=='f')
-						    _res.lookups[n++] = *sp;
+						    _resp->lookups[n++] = *sp;
 					    sp = NULL;
 				    }
 			    } else if (sp == NULL)
@@ -319,17 +333,17 @@ res_init()
 			    cp++;
 		    if ((*cp == '\0') || (*cp == '\n'))
 			    continue;
-		    strlcpy(_res.defdname, cp, sizeof(_res.defdname));
-		    if ((cp = strchr(_res.defdname, '\n')) != NULL)
+		    strlcpy(_resp->defdname, cp, sizeof(_resp->defdname));
+		    if ((cp = strchr(_resp->defdname, '\n')) != NULL)
 			    *cp = '\0';
 		    /*
 		     * Set search list to be blank-separated strings
 		     * on rest of line.
 		     */
-		    cp = _res.defdname;
-		    pp = _res.dnsrch;
+		    cp = _resp->defdname;
+		    pp = _resp->dnsrch;
 		    *pp++ = cp;
-		    for (n = 0; *cp && pp < _res.dnsrch + MAXDNSRCH; cp++) {
+		    for (n = 0; *cp && pp < _resp->dnsrch + MAXDNSRCH; cp++) {
 			    if (*cp == ' ' || *cp == '\t') {
 				    *cp = 0;
 				    n = 1;
@@ -375,19 +389,19 @@ res_init()
 		    res = NULL;
 		    if (getaddrinfo(cp, pbuf, &hints, &res) == 0 &&
 			    res->ai_next == NULL) {
-			if (res->ai_addrlen <= sizeof(_res_ext.nsaddr_list[nserv])) {
-			    memcpy(&_res_ext.nsaddr_list[nserv], res->ai_addr,
+			if (res->ai_addrlen <= sizeof(_res_extp->nsaddr_list[nserv])) {
+			    memcpy(&_res_extp->nsaddr_list[nserv], res->ai_addr,
 				res->ai_addrlen);
 			} else {
-			    memset(&_res_ext.nsaddr_list[nserv], 0,
-				sizeof(_res_ext.nsaddr_list[nserv]));
+			    memset(&_res_extp->nsaddr_list[nserv], 0,
+				sizeof(_res_extp->nsaddr_list[nserv]));
 			}
-			if (res->ai_addrlen <= sizeof(_res.nsaddr_list[nserv])) {
-			    memcpy(&_res.nsaddr_list[nserv], res->ai_addr,
+			if (res->ai_addrlen <= sizeof(_resp->nsaddr_list[nserv])) {
+			    memcpy(&_resp->nsaddr_list[nserv], res->ai_addr,
 				res->ai_addrlen);
 			} else {
-			    memset(&_res.nsaddr_list[nserv], 0,
-				sizeof(_res.nsaddr_list[nserv]));
+			    memset(&_resp->nsaddr_list[nserv], 0,
+				sizeof(_resp->nsaddr_list[nserv]));
 			}
 			nserv++;
 		    }
@@ -395,11 +409,11 @@ res_init()
 			freeaddrinfo(res);
 #else /* INET6 */
 		    if ((*cp != '\0') && (*cp != '\n') && inet_aton(cp, &a)) {
-			_res.nsaddr_list[nserv].sin_addr = a;
-			_res.nsaddr_list[nserv].sin_family = AF_INET;
-			_res.nsaddr_list[nserv].sin_port =
+			_resp->nsaddr_list[nserv].sin_addr = a;
+			_resp->nsaddr_list[nserv].sin_family = AF_INET;
+			_resp->nsaddr_list[nserv].sin_port =
 				htons(NAMESERVER_PORT);
-			_res.nsaddr_list[nserv].sin_len =
+			_resp->nsaddr_list[nserv].sin_len =
 				sizeof(struct sockaddr_in);
 			nserv++;
 		    }
@@ -428,7 +442,7 @@ res_init()
 			n = *cp;
 			*cp = 0;
 			if (inet_aton(net, &a)) {
-			    _res.sort_list[nsort].addr = a;
+			    _resp->sort_list[nsort].addr = a;
 			    if (ISSORTMASK(n)) {
 				*cp++ = n;
 				net = cp;
@@ -438,29 +452,29 @@ res_init()
 				n = *cp;
 				*cp = 0;
 				if (inet_aton(net, &a)) {
-				    _res.sort_list[nsort].mask = a.s_addr;
+				    _resp->sort_list[nsort].mask = a.s_addr;
 				} else {
-				    _res.sort_list[nsort].mask = 
-					net_mask(_res.sort_list[nsort].addr);
+				    _resp->sort_list[nsort].mask = 
+					net_mask(_resp->sort_list[nsort].addr);
 				}
 			    } else {
-				_res.sort_list[nsort].mask = 
-				    net_mask(_res.sort_list[nsort].addr);
+				_resp->sort_list[nsort].mask = 
+				    net_mask(_resp->sort_list[nsort].addr);
 			    }
 #ifdef INET6
-			    _res_ext.sort_list[nsort].af = AF_INET;
-			    _res_ext.sort_list[nsort].addr.ina =
-				_res.sort_list[nsort].addr;
-			    _res_ext.sort_list[nsort].mask.ina.s_addr =
-				_res.sort_list[nsort].mask;
+			    _res_extp->sort_list[nsort].af = AF_INET;
+			    _res_extp->sort_list[nsort].addr.ina =
+				_resp->sort_list[nsort].addr;
+			    _res_extp->sort_list[nsort].mask.ina.s_addr =
+				_resp->sort_list[nsort].mask;
 #endif /* INET6 */
 			    nsort++;
 			}
 #ifdef INET6
 			else if (inet_pton(AF_INET6, net, &a6) == 1) {
-			    _res_ext.sort_list[nsort].af = AF_INET6;
-			    _res_ext.sort_list[nsort].addr.in6a = a6;
-			    u = (u_char *)&_res_ext.sort_list[nsort].mask.in6a;
+			    _res_extp->sort_list[nsort].af = AF_INET6;
+			    _res_extp->sort_list[nsort].addr.in6a = a6;
+			    u = (u_char *)&_res_extp->sort_list[nsort].mask.in6a;
 			    *cp++ = n;
 			    net = cp;
 			    while (*cp && *cp != ';' &&
@@ -510,33 +524,33 @@ res_init()
 		}
 	    }
 	    if (nserv > 1) 
-		_res.nscount = nserv;
+		_resp->nscount = nserv;
 #ifdef RESOLVSORT
-	    _res.nsort = nsort;
+	    _resp->nsort = nsort;
 #endif
 	    (void) fclose(fp);
 	}
-	if (_res.defdname[0] == 0 &&
-	    gethostname(buf, sizeof(_res.defdname) - 1) == 0 &&
+	if (_resp->defdname[0] == 0 &&
+	    gethostname(buf, sizeof(_resp->defdname) - 1) == 0 &&
 	    (cp = strchr(buf, '.')) != NULL)
 	{
-		strlcpy(_res.defdname, cp + 1,
-		        sizeof(_res.defdname));
+		strlcpy(_resp->defdname, cp + 1,
+		        sizeof(_resp->defdname));
 	}
 
 	/* find components of local domain that might be searched */
 	if (havesearch == 0) {
-		pp = _res.dnsrch;
-		*pp++ = _res.defdname;
+		pp = _resp->dnsrch;
+		*pp++ = _resp->defdname;
 		*pp = NULL;
 
 #ifndef RFC1535
 		dots = 0;
-		for (cp = _res.defdname; *cp; cp++)
+		for (cp = _resp->defdname; *cp; cp++)
 			dots += (*cp == '.');
 
-		cp = _res.defdname;
-		while (pp < _res.dnsrch + MAXDFLSRCH) {
+		cp = _resp->defdname;
+		while (pp < _resp->dnsrch + MAXDFLSRCH) {
 			if (dots < LOCALDOMAINPARTS)
 				break;
 			cp = strchr(cp, '.') + 1;    /* we know there is one */
@@ -545,9 +559,9 @@ res_init()
 		}
 		*pp = NULL;
 #ifdef DEBUG
-		if (_res.options & RES_DEBUG) {
+		if (_resp->options & RES_DEBUG) {
 			printf(";; res_init()... default dnsrch list:\n");
-			for (pp = _res.dnsrch; *pp; pp++)
+			for (pp = _resp->dnsrch; *pp; pp++)
 				printf(";;\t%s\n", *pp);
 			printf(";;\t..END..\n");
 		}
@@ -556,10 +570,10 @@ res_init()
 	}
 
 	if (issetugid())
-		_res.options |= RES_NOALIASES;
+		_resp->options |= RES_NOALIASES;
 	else if ((cp = getenv("RES_OPTIONS")) != NULL)
 		res_setoptions(cp, "env");
-	_res.options |= RES_INIT;
+	_resp->options |= RES_INIT;
 	return (0);
 }
 
@@ -568,12 +582,13 @@ static void
 res_setoptions(options, source)
 	char *options, *source;
 {
+	struct __res_state *_resp = _THREAD_PRIVATE(_res, _res, &_res);
 	char *cp = options;
 	char *endp;
 	long l;
 
 #ifdef DEBUG
-	if (_res.options & RES_DEBUG)
+	if (_resp->options & RES_DEBUG)
 		printf(";; res_setoptions(\"%s\", \"%s\")...\n",
 		       options, source);
 #endif
@@ -588,31 +603,31 @@ res_setoptions(options, source)
 			if (l >= 0 && endp != p &&
 			    (*endp = '\0' || isspace(*endp))) {
 				if (l <= RES_MAXNDOTS)
-					_res.ndots = l;
+					_resp->ndots = l;
 				else
-					_res.ndots = RES_MAXNDOTS;
+					_resp->ndots = RES_MAXNDOTS;
 #ifdef DEBUG
-				if (_res.options & RES_DEBUG)
-					printf(";;\tndots=%u\n", _res.ndots);
+				if (_resp->options & RES_DEBUG)
+					printf(";;\tndots=%u\n", _resp->ndots);
 #endif
 			}
 		} else if (!strncmp(cp, "debug", sizeof("debug") - 1)) {
 #ifdef DEBUG
-			if (!(_res.options & RES_DEBUG)) {
+			if (!(_resp->options & RES_DEBUG)) {
 				printf(";; res_setoptions(\"%s\", \"%s\")..\n",
 				       options, source);
-				_res.options |= RES_DEBUG;
+				_resp->options |= RES_DEBUG;
 			}
 			printf(";;\tdebug\n");
 #endif
 		} else if (!strncmp(cp, "inet6", sizeof("inet6") - 1)) {
-			_res.options |= RES_USE_INET6;
+			_resp->options |= RES_USE_INET6;
 		} else if (!strncmp(cp, "insecure1", sizeof("insecure1") - 1)) {
-			_res.options |= RES_INSECURE1;
+			_resp->options |= RES_INSECURE1;
 		} else if (!strncmp(cp, "insecure2", sizeof("insecure2") - 1)) {
-			_res.options |= RES_INSECURE2;
+			_resp->options |= RES_INSECURE2;
 		} else if (!strncmp(cp, "edns0", sizeof("edns0") - 1)) {
-			_res.options |= RES_USE_EDNS0;
+			_resp->options |= RES_USE_EDNS0;
 		} else {
 			/* XXX - print a warning here? */
 		}
diff --git a/lib/libc/net/res_mkquery.c b/lib/libc/net/res_mkquery.c
index 6cd6a00dbe4..bb8f1f07258 100644
--- a/lib/libc/net/res_mkquery.c
+++ b/lib/libc/net/res_mkquery.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: res_mkquery.c,v 1.12 2002/08/28 03:19:38 itojun Exp $	*/
+/*	$OpenBSD: res_mkquery.c,v 1.13 2003/01/28 04:58:00 marc Exp $	*/
 
 /*
  * ++Copyright++ 1985, 1993
@@ -60,7 +60,7 @@
 static char sccsid[] = "@(#)res_mkquery.c	8.1 (Berkeley) 6/4/93";
 static char rcsid[] = "$From: res_mkquery.c,v 8.5 1996/08/27 08:33:28 vixie Exp $";
 #else
-static char rcsid[] = "$OpenBSD: res_mkquery.c,v 1.12 2002/08/28 03:19:38 itojun Exp $";
+static char rcsid[] = "$OpenBSD: res_mkquery.c,v 1.13 2003/01/28 04:58:00 marc Exp $";
 #endif
 #endif /* LIBC_SCCS and not lint */
 
@@ -74,6 +74,8 @@ static char rcsid[] = "$OpenBSD: res_mkquery.c,v 1.12 2002/08/28 03:19:38 itojun
 #include <resolv.h>
 #include <string.h>
 
+#include "thread_private.h"
+
 /*
  * Form all types of queries.
  * Returns the size of the result or -1.
@@ -90,17 +92,18 @@ res_mkquery(op, dname, class, type, data, datalen, newrr_in, buf, buflen)
 	u_char *buf;		/* buffer to put query */
 	int buflen;		/* size of buffer */
 {
+	struct __res_state *_resp = _THREAD_PRIVATE(_res, _res, &_res);
 	register HEADER *hp;
 	register u_char *cp, *ep;
 	register int n;
 	u_char *dnptrs[20], **dpp, **lastdnptr;
 
-	if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
+	if ((_resp->options & RES_INIT) == 0 && res_init() == -1) {
 		h_errno = NETDB_INTERNAL;
 		return (-1);
 	}
 #ifdef DEBUG
-	if (_res.options & RES_DEBUG)
+	if (_resp->options & RES_DEBUG)
 		printf(";; res_mkquery(%d, %s, %d, %d)\n",
 		       op, dname, class, type);
 #endif
@@ -116,10 +119,10 @@ res_mkquery(op, dname, class, type, data, datalen, newrr_in, buf, buflen)
 		return (-1);
 	bzero(buf, HFIXEDSZ);
 	hp = (HEADER *) buf;
-	_res.id = res_randomid();
-	hp->id = htons(_res.id);
+	_resp->id = res_randomid();
+	hp->id = htons(_resp->id);
 	hp->opcode = op;
-	hp->rd = (_res.options & RES_RECURSE) != 0;
+	hp->rd = (_resp->options & RES_RECURSE) != 0;
 	hp->rcode = NOERROR;
 	cp = buf + HFIXEDSZ;
 	ep = buf + buflen;
@@ -203,6 +206,7 @@ res_opt(n0, buf, buflen, anslen)
 	int buflen;		/* size of buffer */
 	int anslen;		/* answer buffer length */
 {
+	struct __res_state *_resp = _THREAD_PRIVATE(_res, _res, &_res);
 	register HEADER *hp;
 	register u_char *cp, *ep;
 
@@ -223,9 +227,9 @@ res_opt(n0, buf, buflen, anslen)
 	cp += INT16SZ;
 	*cp++ = NOERROR;	/* extended RCODE */
 	*cp++ = 0;		/* EDNS version */
-	if (_res.options & RES_USE_DNSSEC) {
+	if (_resp->options & RES_USE_DNSSEC) {
 #ifdef DEBUG
-		if (_res.options & RES_DEBUG)
+		if (_resp->options & RES_DEBUG)
 			printf(";; res_opt()... ENDS0 DNSSEC OK\n");
 #endif /* DEBUG */
 		__putshort(DNS_MESSAGEEXTFLAG_DO, cp);	/* EDNS Z field */
diff --git a/lib/libc/net/res_query.c b/lib/libc/net/res_query.c
index 9c1aef1218f..1e949e8efaf 100644
--- a/lib/libc/net/res_query.c
+++ b/lib/libc/net/res_query.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: res_query.c,v 1.19 2002/06/27 09:55:49 itojun Exp $	*/
+/*	$OpenBSD: res_query.c,v 1.20 2003/01/28 04:58:00 marc Exp $	*/
 
 /*
  * ++Copyright++ 1988, 1993
@@ -60,7 +60,7 @@
 static char sccsid[] = "@(#)res_query.c	8.1 (Berkeley) 6/4/93";
 static char rcsid[] = "$From: res_query.c,v 8.9 1996/09/22 00:13:28 vixie Exp $";
 #else
-static char rcsid[] = "$OpenBSD: res_query.c,v 1.19 2002/06/27 09:55:49 itojun Exp $";
+static char rcsid[] = "$OpenBSD: res_query.c,v 1.20 2003/01/28 04:58:00 marc Exp $";
 #endif
 #endif /* LIBC_SCCS and not lint */
 
@@ -79,6 +79,8 @@ static char rcsid[] = "$OpenBSD: res_query.c,v 1.19 2002/06/27 09:55:49 itojun E
 #include <string.h>
 #include <unistd.h>
 
+#include "thread_private.h"
+
 #if PACKETSZ > 1024
 #define MAXPACKET	PACKETSZ
 #else
@@ -106,31 +108,32 @@ res_query(name, class, type, answer, anslen)
 	u_char *answer;		/* buffer to put answer */
 	int anslen;		/* size of answer buffer */
 {
+	struct __res_state *_resp = _THREAD_PRIVATE(_res, _res, &_res);
 	u_char buf[MAXPACKET];
 	register HEADER *hp = (HEADER *) answer;
 	int n;
 
 	hp->rcode = NOERROR;	/* default */
 
-	if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
+	if ((_resp->options & RES_INIT) == 0 && res_init() == -1) {
 		h_errno = NETDB_INTERNAL;
 		return (-1);
 	}
 #ifdef DEBUG
-	if (_res.options & RES_DEBUG)
+	if (_resp->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 && ((_res.options & RES_USE_EDNS0) ||
-	    (_res.options & RES_USE_DNSSEC))) {
+	if (n > 0 && ((_resp->options & RES_USE_EDNS0) ||
+	    (_resp->options & RES_USE_DNSSEC))) {
 		n = res_opt(n, buf, sizeof(buf), anslen);
 	}
 
 	if (n <= 0) {
 #ifdef DEBUG
-		if (_res.options & RES_DEBUG)
+		if (_resp->options & RES_DEBUG)
 			printf(";; res_query: mkquery failed\n");
 #endif
 		h_errno = NO_RECOVERY;
@@ -139,7 +142,7 @@ res_query(name, class, type, answer, anslen)
 	n = res_send(buf, n, answer, anslen);
 	if (n < 0) {
 #ifdef DEBUG
-		if (_res.options & RES_DEBUG)
+		if (_resp->options & RES_DEBUG)
 			printf(";; res_query: send error\n");
 #endif
 		h_errno = TRY_AGAIN;
@@ -148,7 +151,7 @@ res_query(name, class, type, answer, anslen)
 
 	if (hp->rcode != NOERROR || ntohs(hp->ancount) == 0) {
 #ifdef DEBUG
-		if (_res.options & RES_DEBUG)
+		if (_resp->options & RES_DEBUG)
 			printf(";; rcode = %u, ancount=%u\n", hp->rcode,
 			    ntohs(hp->ancount));
 #endif
@@ -188,12 +191,13 @@ res_search(name, class, type, answer, anslen)
 	int anslen;		/* size of answer */
 {
 	register const char *cp, * const *domain;
+	struct __res_state *_resp = _THREAD_PRIVATE(_res, _res, &_res);
 	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) {
+	if ((_resp->options & RES_INIT) == 0 && res_init() == -1) {
 		h_errno = NETDB_INTERNAL;
 		return (-1);
 	}
@@ -217,7 +221,7 @@ res_search(name, class, type, answer, anslen)
 	 * 'as is'.  The threshold can be set with the "ndots" option.
 	 */
 	saved_herrno = -1;
-	if (dots >= _res.ndots) {
+	if (dots >= _resp->ndots) {
 		ret = res_querydomain(name, NULL, class, type, answer, anslen);
 		if (ret > 0)
 			return (ret);
@@ -231,11 +235,11 @@ res_search(name, class, type, answer, anslen)
 	 *	- 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))) {
+	if ((!dots && (_resp->options & RES_DEFNAMES)) ||
+	    (dots && !trailing_dot && (_resp->options & RES_DNSRCH))) {
 		int done = 0;
 
-		for (domain = (const char * const *)_res.dnsrch;
+		for (domain = (const char * const *)_resp->dnsrch;
 		     *domain && !done;
 		     domain++) {
 
@@ -284,7 +288,7 @@ res_search(name, class, type, answer, anslen)
 			/* 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))
+			if (!(_resp->options & RES_DNSRCH))
 				done++;
 		}
 	}
@@ -326,16 +330,17 @@ res_querydomain(name, domain, class, type, answer, anslen)
 	u_char *answer;		/* buffer to put answer */
 	int anslen;		/* size of answer */
 {
+	struct __res_state *_resp = _THREAD_PRIVATE(_res, _res, &_res);
 	char nbuf[MAXDNAME*2+1+1];
 	const char *longname = nbuf;
 	int n;
 
-	if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
+	if ((_resp->options & RES_INIT) == 0 && res_init() == -1) {
 		h_errno = NETDB_INTERNAL;
 		return (-1);
 	}
 #ifdef DEBUG
-	if (_res.options & RES_DEBUG)
+	if (_resp->options & RES_DEBUG)
 		printf(";; res_querydomain(%s, %s, %d, %d)\n",
 		       name, domain?domain:"<Nil>", class, type);
 #endif
@@ -361,6 +366,7 @@ const char *
 hostalias(name)
 	register const char *name;
 {
+	struct __res_state *_resp = _THREAD_PRIVATE(_res, _res, &_res);
 	register char *cp1, *cp2;
 	FILE *fp;
 	char *file;
@@ -368,7 +374,7 @@ hostalias(name)
 	static char abuf[MAXDNAME];
 	size_t len;
 
-	if (_res.options & RES_NOALIASES)
+	if (_resp->options & RES_NOALIASES)
 		return (NULL);
 	file = getenv("HOSTALIASES");
 	if (issetugid() != 0 || file == NULL || (fp = fopen(file, "r")) == NULL)
diff --git a/lib/libc/net/res_send.c b/lib/libc/net/res_send.c
index b043e7c9fb7..282675a533d 100644
--- a/lib/libc/net/res_send.c
+++ b/lib/libc/net/res_send.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: res_send.c,v 1.12 2002/09/06 18:35:12 deraadt Exp $	*/
+/*	$OpenBSD: res_send.c,v 1.13 2003/01/28 04:58:00 marc Exp $	*/
 
 /*
  * ++Copyright++ 1985, 1989, 1993
@@ -64,7 +64,7 @@
 static char sccsid[] = "@(#)res_send.c	8.1 (Berkeley) 6/4/93";
 static char rcsid[] = "$From: res_send.c,v 8.12 1996/10/08 04:51:06 vixie Exp $";
 #else
-static char rcsid[] = "$OpenBSD: res_send.c,v 1.12 2002/09/06 18:35:12 deraadt Exp $";
+static char rcsid[] = "$OpenBSD: res_send.c,v 1.13 2003/01/28 04:58:00 marc Exp $";
 #endif
 #endif /* LIBC_SCCS and not lint */
 
@@ -96,6 +96,8 @@ static char rcsid[] = "$OpenBSD: res_send.c,v 1.12 2002/09/06 18:35:12 deraadt E
 #include <string.h>
 #include <unistd.h>
 
+#include "thread_private.h"
+
 static int s = -1;	/* socket used for communications */
 static int connected = 0;	/* is the socket connected */
 static int vc = 0;	/* is the socket a virtual ciruit? */
@@ -136,9 +138,10 @@ static void Perror(FILE *, char *, int);
 	int error;
 	struct sockaddr *address;
     {
+	struct __res_state *_resp = _THREAD_PRIVATE(_res, _res, &_res);
 	int save = errno;
 
-	if (_res.options & RES_DEBUG) {
+	if (_resp->options & RES_DEBUG) {
 		if (getnameinfo(address, address->sa_len, abuf, sizeof(abuf),
 		    pbuf, sizeof(pbuf),
 		    NI_NUMERICHOST|NI_NUMERICSERV|NI_WITHSCOPEID) != 0) {
@@ -156,9 +159,10 @@ static void Perror(FILE *, char *, int);
 	char *string;
 	int error;
     {
+	struct __res_state *_resp = _THREAD_PRIVATE(_res, _res, &_res);
 	int save = errno;
 
-	if (_res.options & RES_DEBUG) {
+	if (_resp->options & RES_DEBUG) {
 		fprintf(file, "res_send: %s: %s\n",
 			string, strerror(error));
 	}
@@ -195,30 +199,33 @@ static struct sockaddr *
 get_nsaddr(n)
 	size_t n;
 {
+	struct __res_state *_resp = _THREAD_PRIVATE(_res, _res, &_res);
+	struct __res_state_ext *_res_extp = _THREAD_PRIVATE(_res_ext, _res_ext,
+							    &_res_ext);
 
-	if (!_res.nsaddr_list[n].sin_family) {
+	if (!_resp->nsaddr_list[n].sin_family) {
 		/*
-		 * - _res_ext.nsaddr_list[n] holds an address that is larger
+		 * - _res_extp->nsaddr_list[n] holds an address that is larger
 		 *   than struct sockaddr, and
-		 * - user code did not update _res.nsaddr_list[n].
+		 * - user code did not update _resp->nsaddr_list[n].
 		 */
-		return (struct sockaddr *)&_res_ext.nsaddr_list[n];
+		return (struct sockaddr *)&_res_extp->nsaddr_list[n];
 	} else {
 		/*
 		 * - user code updated _res.nsaddr_list[n], or
-		 * - _res.nsaddr_list[n] has the same content as
-		 *   _res_ext.nsaddr_list[n].
+		 * - _resp->nsaddr_list[n] has the same content as
+		 *   _res_extp->nsaddr_list[n].
 		 */
-		return (struct sockaddr *)&_res.nsaddr_list[n];
+		return (struct sockaddr *)&_resp->nsaddr_list[n];
 	}
 }
 #else
-#define get_nsaddr(n)	((struct sockaddr *)&_res.nsaddr_list[(n)])
+#define get_nsaddr(n)	((struct sockaddr *)&_resp->nsaddr_list[(n)])
 #endif
 
 /* int
  * res_isourserver(ina)
- *	looks up "ina" in _res.ns_addr_list[]
+ *	looks up "ina" in _resp->ns_addr_list[]
  * returns:
  *	0  : not found
  *	>0 : found
@@ -229,6 +236,7 @@ int
 res_isourserver(inp)
 	const struct sockaddr_in *inp;
 {
+	struct __res_state *_resp = _THREAD_PRIVATE(_res, _res, &_res);
 #ifdef INET6
 	const struct sockaddr_in6 *in6p = (const struct sockaddr_in6 *)inp;
 	const struct sockaddr_in6 *srv6;
@@ -240,7 +248,7 @@ res_isourserver(inp)
 	switch (inp->sin_family) {
 #ifdef INET6
 	case AF_INET6:
-		for (ns = 0; ns < _res.nscount; ns++) {
+		for (ns = 0; ns < _resp->nscount; ns++) {
 			srv6 = (struct sockaddr_in6 *)get_nsaddr(ns);
 			if (srv6->sin6_family == in6p->sin6_family &&
 			    srv6->sin6_port == in6p->sin6_port &&
@@ -255,7 +263,7 @@ res_isourserver(inp)
 		break;
 #endif
 	case AF_INET:
-		for (ns = 0; ns < _res.nscount; ns++) {
+		for (ns = 0; ns < _resp->nscount; ns++) {
 			srv = (struct sockaddr_in *)get_nsaddr(ns);
 			if (srv->sin_family == inp->sin_family &&
 			    srv->sin_port == inp->sin_port &&
@@ -351,19 +359,20 @@ res_send(buf, buflen, ans, anssiz)
 	u_char *ans;
 	int anssiz;
 {
+	struct __res_state *_resp = _THREAD_PRIVATE(_res, _res, &_res);
 	HEADER *hp = (HEADER *) buf;
 	HEADER *anhp = (HEADER *) ans;
 	int gotsomewhere, connreset, terrno, try, v_circuit, resplen, ns;
 	register int n;
 	u_int badns;	/* XXX NSMAX can't exceed #/bits in this var */
 
-	if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
+	if ((_resp->options & RES_INIT) == 0 && res_init() == -1) {
 		/* errno should have been set by res_init() in this case. */
 		return (-1);
 	}
-	DprintQ((_res.options & RES_DEBUG) || (_res.pfcode & RES_PRF_QUERY),
+	DprintQ((_resp->options & RES_DEBUG) || (_resp->pfcode & RES_PRF_QUERY),
 		(stdout, ";; res_send()\n"), buf, buflen);
-	v_circuit = (_res.options & RES_USEVC) || buflen > PACKETSZ;
+	v_circuit = (_resp->options & RES_USEVC) || buflen > PACKETSZ;
 	gotsomewhere = 0;
 	connreset = 0;
 	terrno = ETIMEDOUT;
@@ -372,8 +381,8 @@ res_send(buf, buflen, ans, anssiz)
 	/*
 	 * Send request, RETRY times, or until successful
 	 */
-	for (try = 0; try < _res.retry; try++) {
-	    for (ns = 0; ns < _res.nscount; ns++) {
+	for (try = 0; try < _resp->retry; try++) {
+	    for (ns = 0; ns < _resp->nscount; ns++) {
 		struct sockaddr *nsap = get_nsaddr(ns);
 		socklen_t salen;
 
@@ -425,7 +434,7 @@ res_send(buf, buflen, ans, anssiz)
 			} while (!done);
 		}
 
-		Dprint((_res.options & RES_DEBUG) &&
+		Dprint((_resp->options & RES_DEBUG) &&
 		       getnameinfo(nsap, salen, abuf, sizeof(abuf),
 			   NULL, 0, NI_NUMERICHOST | NI_WITHSCOPEID) == 0,
 		       (stdout, ";; Querying server (# %d) address = %s\n",
@@ -441,7 +450,7 @@ res_send(buf, buflen, ans, anssiz)
 			 * Use virtual circuit;
 			 * at most one attempt per server.
 			 */
-			try = _res.retry;
+			try = _resp->retry;
 			truncated = 0;
 			if ((s < 0) || (!vc) || (af != nsap->sa_family)) {
 				if (s >= 0)
@@ -520,7 +529,7 @@ read_len:
 			}
 			resplen = _getshort(ans);
 			if (resplen > anssiz) {
-				Dprint(_res.options & RES_DEBUG,
+				Dprint(_resp->options & RES_DEBUG,
 				       (stdout, ";; response truncated\n")
 				       );
 				truncated = 1;
@@ -566,8 +575,8 @@ read_len:
 			 * wait for the correct one.
 			 */
 			if (hp->id != anhp->id) {
-				DprintQ((_res.options & RES_DEBUG) ||
-					(_res.pfcode & RES_PRF_REPLY),
+				DprintQ((_resp->options & RES_DEBUG) ||
+					(_resp->pfcode & RES_PRF_REPLY),
 					(stdout, ";; old answer (unexpected):\n"),
 					ans, (resplen>anssiz)?anssiz:resplen);
 				goto read_len;
@@ -625,8 +634,8 @@ read_len:
 			 * as we wish to receive answers from the first
 			 * server to respond.
 			 */
-			if (!(_res.options & RES_INSECURE1) &&
-			    (_res.nscount == 1 || (try == 0 && ns == 0))) {
+			if (!(_resp->options & RES_INSECURE1) &&
+			    (_resp->nscount == 1 || (try == 0 && ns == 0))) {
 				/*
 				 * Connect only if we are sure we won't
 				 * receive a response from another server.
@@ -673,7 +682,7 @@ read_len:
 						goto bad_dg_sock;
 					(void) dup2(s1, s);
 					(void) close(s1);
-					Dprint(_res.options & RES_DEBUG,
+					Dprint(_resp->options & RES_DEBUG,
 					       (stdout, ";; new DG socket\n"))
 #endif
 #ifdef IPV6_MINMTU
@@ -699,9 +708,9 @@ read_len:
 			/*
 			 * Wait for reply
 			 */
-			timeout.tv_sec = (_res.retrans << try);
+			timeout.tv_sec = (_resp->retrans << try);
 			if (try > 0)
-				timeout.tv_sec /= _res.nscount;
+				timeout.tv_sec /= _resp->nscount;
 			if ((long) timeout.tv_sec <= 0)
 				timeout.tv_sec = 1;
 			timeout.tv_usec = 0;
@@ -727,7 +736,7 @@ read_len:
 				/*
 				 * timeout
 				 */
-				Dprint(_res.options & RES_DEBUG,
+				Dprint(_resp->options & RES_DEBUG,
 				       (stdout, ";; timeout\n"));
 				gotsomewhere = 1;
 				res_close();
@@ -749,28 +758,28 @@ read_len:
 				 * XXX - potential security hazard could
 				 *	 be detected here.
 				 */
-				DprintQ((_res.options & RES_DEBUG) ||
-					(_res.pfcode & RES_PRF_REPLY),
+				DprintQ((_resp->options & RES_DEBUG) ||
+					(_resp->pfcode & RES_PRF_REPLY),
 					(stdout, ";; old answer:\n"),
 					ans, (resplen>anssiz)?anssiz:resplen);
 				goto wait;
 			}
 #if CHECK_SRVR_ADDR
-			if (!(_res.options & RES_INSECURE1) &&
+			if (!(_resp->options & RES_INSECURE1) &&
 			    !res_isourserver((struct sockaddr_in *)&from)) {
 				/*
 				 * response from wrong server? ignore it.
 				 * XXX - potential security hazard could
 				 *	 be detected here.
 				 */
-				DprintQ((_res.options & RES_DEBUG) ||
-					(_res.pfcode & RES_PRF_REPLY),
+				DprintQ((_resp->options & RES_DEBUG) ||
+					(_resp->pfcode & RES_PRF_REPLY),
 					(stdout, ";; not our server:\n"),
 					ans, (resplen>anssiz)?anssiz:resplen);
 				goto wait;
 			}
 #endif
-			if (!(_res.options & RES_INSECURE2) &&
+			if (!(_resp->options & RES_INSECURE2) &&
 			    !res_queriesmatch(buf, buf + buflen,
 					      ans, ans + anssiz)) {
 				/*
@@ -778,8 +787,8 @@ read_len:
 				 * XXX - potential security hazard could
 				 *	 be detected here.
 				 */
-				DprintQ((_res.options & RES_DEBUG) ||
-					(_res.pfcode & RES_PRF_REPLY),
+				DprintQ((_resp->options & RES_DEBUG) ||
+					(_resp->pfcode & RES_PRF_REPLY),
 					(stdout, ";; wrong query name:\n"),
 					ans, (resplen>anssiz)?anssiz:resplen);
 				goto wait;
@@ -787,33 +796,33 @@ read_len:
 			if (anhp->rcode == SERVFAIL ||
 			    anhp->rcode == NOTIMP ||
 			    anhp->rcode == REFUSED) {
-				DprintQ(_res.options & RES_DEBUG,
+				DprintQ(_resp->options & RES_DEBUG,
 					(stdout, "server rejected query:\n"),
 					ans, (resplen>anssiz)?anssiz:resplen);
 				badns |= (1 << ns);
 				res_close();
 				/* don't retry if called from dig */
-				if (!_res.pfcode)
+				if (!_resp->pfcode)
 					goto next_ns;
 			}
-			if (!(_res.options & RES_IGNTC) && anhp->tc) {
+			if (!(_resp->options & RES_IGNTC) && anhp->tc) {
 				/*
 				 * get rest of answer;
 				 * use TCP with same server.
 				 */
-				Dprint(_res.options & RES_DEBUG,
+				Dprint(_resp->options & RES_DEBUG,
 				       (stdout, ";; truncated answer\n"));
 				v_circuit = 1;
 				res_close();
 				goto same_ns;
 			}
 		} /*if vc/dg*/
-		Dprint((_res.options & RES_DEBUG) ||
-		       ((_res.pfcode & RES_PRF_REPLY) &&
-			(_res.pfcode & RES_PRF_HEAD1)),
+		Dprint((_resp->options & RES_DEBUG) ||
+		       ((_resp->pfcode & RES_PRF_REPLY) &&
+			(_resp->pfcode & RES_PRF_HEAD1)),
 		       (stdout, ";; got answer:\n"));
-		DprintQ((_res.options & RES_DEBUG) ||
-			(_res.pfcode & RES_PRF_REPLY),
+		DprintQ((_resp->options & RES_DEBUG) ||
+			(_resp->pfcode & RES_PRF_REPLY),
 			(stdout, "%s", ""),
 			ans, (resplen>anssiz)?anssiz:resplen);
 		/*
@@ -824,8 +833,8 @@ read_len:
 		 * or if we haven't been asked to keep a socket open,
 		 * close the socket.
 		 */
-		if ((v_circuit && (!(_res.options & RES_USEVC) || ns != 0)) ||
-		    !(_res.options & RES_STAYOPEN)) {
+		if ((v_circuit && (!(_resp->options & RES_USEVC) || ns != 0)) ||
+		    !(_resp->options & RES_STAYOPEN)) {
 			res_close();
 		}
 		if (Rhook) {
diff --git a/lib/libc/net/sethostent.c b/lib/libc/net/sethostent.c
index 5392a2f11bb..40a5a809629 100644
--- a/lib/libc/net/sethostent.c
+++ b/lib/libc/net/sethostent.c
@@ -32,7 +32,7 @@
  */
 
 #if defined(LIBC_SCCS) && !defined(lint)
-static char rcsid[] = "$OpenBSD: sethostent.c,v 1.4 1997/03/15 21:53:50 pefo Exp $";
+static char rcsid[] = "$OpenBSD: sethostent.c,v 1.5 2003/01/28 04:58:00 marc Exp $";
 #endif /* LIBC_SCCS and not lint */
 
 #include <sys/param.h>
@@ -41,20 +41,25 @@ static char rcsid[] = "$OpenBSD: sethostent.c,v 1.4 1997/03/15 21:53:50 pefo Exp
 #include <netdb.h>
 #include <resolv.h>
 
+#include "thread_private.h"
+
 void
 sethostent(stayopen)
 	int stayopen;
 {
+	struct __res_state *_resp = _THREAD_PRIVATE(_res, _res, &_res);
 
-	if ((_res.options & RES_INIT) == 0 && res_init() == -1)
+	if ((_resp->options & RES_INIT) == 0 && res_init() == -1)
 		return;
 	if (stayopen)
-		_res.options |= RES_STAYOPEN | RES_USEVC;
+		_resp->options |= RES_STAYOPEN | RES_USEVC;
 }
 
 void
 endhostent()
 {
-	_res.options &= ~(RES_STAYOPEN | RES_USEVC);
+	struct __res_state *_resp = _THREAD_PRIVATE(_res, _res, &_res);
+
+	_resp->options &= ~(RES_STAYOPEN | RES_USEVC);
 	res_close();
 }