OpenSolaris Launch

12 files changed, 1804 insertions, 0 deletions

diff --git a/usr/src/lib/nsswitch/dns/Makefile b/usr/src/lib/nsswitch/dns/Makefile
new file mode 100644
index 0000000000..9fc3326ce3
--- /dev/null
+++ b/usr/src/lib/nsswitch/dns/Makefile
@@ -0,0 +1,47 @@
+#
+# CDDL HEADER START
+#
+# The contents of this file are subject to the terms of the
+# Common Development and Distribution License, Version 1.0 only
+# (the "License").  You may not use this file except in compliance
+# with the License.
+#
+# You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+# or http://www.opensolaris.org/os/licensing.
+# See the License for the specific language governing permissions
+# and limitations under the License.
+#
+# When distributing Covered Code, include this CDDL HEADER in each
+# file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+# If applicable, add the following below this CDDL HEADER, with the
+# fields enclosed by brackets "[]" replaced with your own identifying
+# information: Portions Copyright [yyyy] [name of copyright owner]
+#
+# CDDL HEADER END
+#
+#
+#ident	"%Z%%M%	%I%	%E% SMI"
+#
+# Copyright (c) 1991 - 1996, by Sun Microsystems, Inc.
+# All rights reserved.
+#
+# lib/nsswitch/dns/Makefile
+
+include     ../../../Makefile.master
+
+FILES_SUBDIRS=    $(MACH) $(BUILD64) $(MACH64)
+
+all:=		TARGET= all
+clean:=		TARGET= clean
+clobber:=	TARGET= clobber
+install:=	TARGET= install
+lint:=		TARGET= lint
+
+.KEEP_STATE:
+
+all clean clobber install lint: $(FILES_SUBDIRS)
+
+$(MACH) $(MACH64): FRC
+	@cd $@; pwd; $(MAKE) $(TARGET)
+
+FRC:
diff --git a/usr/src/lib/nsswitch/dns/Makefile.com b/usr/src/lib/nsswitch/dns/Makefile.com
new file mode 100644
index 0000000000..f4aa3f433c
--- /dev/null
+++ b/usr/src/lib/nsswitch/dns/Makefile.com
@@ -0,0 +1,49 @@
+#
+# CDDL HEADER START
+#
+# The contents of this file are subject to the terms of the
+# Common Development and Distribution License, Version 1.0 only
+# (the "License").  You may not use this file except in compliance
+# with the License.
+#
+# You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+# or http://www.opensolaris.org/os/licensing.
+# See the License for the specific language governing permissions
+# and limitations under the License.
+#
+# When distributing Covered Code, include this CDDL HEADER in each
+# file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+# If applicable, add the following below this CDDL HEADER, with the
+# fields enclosed by brackets "[]" replaced with your own identifying
+# information: Portions Copyright [yyyy] [name of copyright owner]
+#
+# CDDL HEADER END
+#
+#
+# Copyright 2003 Sun Microsystems, Inc.  All rights reserved.
+# Use is subject to license terms.
+#
+# ident	"%Z%%M%	%I%	%E% SMI"
+#
+# lib/nsswitch/dns/Makefile.com
+
+LIBRARY =	libnss_dns.a
+VERS =		.1
+
+OBJECTS =	gethostent.o	\
+		gethostent6.o	\
+		dns_mt.o	\
+		dns_common.o
+
+# include common nsswitch library definitions.
+include		../../Makefile.com
+
+# install this library in the root filesystem
+include ../../../Makefile.rootfs
+
+# Appropriate libresolv loaded at runtime. This is the default, to be dlopened
+# if no libresolv was provided by the application.
+CPPFLAGS +=	-DNSS_DNS_LIBRESOLV=\"libresolv.so.2\"
+
+LDLIBS +=	-lnsl
+DYNLIB1 =	nss_dns.so$(VERS)
diff --git a/usr/src/lib/nsswitch/dns/amd64/Makefile b/usr/src/lib/nsswitch/dns/amd64/Makefile
new file mode 100644
index 0000000000..1334471b25
--- /dev/null
+++ b/usr/src/lib/nsswitch/dns/amd64/Makefile
@@ -0,0 +1,36 @@
+#
+# CDDL HEADER START
+#
+# The contents of this file are subject to the terms of the
+# Common Development and Distribution License, Version 1.0 only
+# (the "License").  You may not use this file except in compliance
+# with the License.
+#
+# You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+# or http://www.opensolaris.org/os/licensing.
+# See the License for the specific language governing permissions
+# and limitations under the License.
+#
+# When distributing Covered Code, include this CDDL HEADER in each
+# file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+# If applicable, add the following below this CDDL HEADER, with the
+# fields enclosed by brackets "[]" replaced with your own identifying
+# information: Portions Copyright [yyyy] [name of copyright owner]
+#
+# CDDL HEADER END
+#
+#
+# Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
+# Use is subject to license terms.
+#
+# ident	"%Z%%M%	%I%	%E% SMI"
+#
+
+include		../Makefile.com
+include		$(SRC)/lib/Makefile.lib.64
+
+LIBS =		$(DYNLIB1)
+
+include		../../Makefile.targ
+
+install:	all $(ROOT64DYNLIB)
diff --git a/usr/src/lib/nsswitch/dns/common/dns_common.c b/usr/src/lib/nsswitch/dns/common/dns_common.c
new file mode 100644
index 0000000000..da766c4d12
--- /dev/null
+++ b/usr/src/lib/nsswitch/dns/common/dns_common.c
@@ -0,0 +1,167 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License, Version 1.0 only
+ * (the "License").  You may not use this file except in compliance
+ * with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or http://www.opensolaris.org/os/licensing.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+/*
+ *	dns_common.c
+ *
+ * Copyright (c) 1993,1998 by Sun Microsystems, Inc.
+ * All rights reserved.
+ */
+
+#pragma	ident	"%Z%%M%	%I%	%E% SMI"
+
+#include "dns_common.h"
+
+#define	DNS_ALIASES	0
+#define	DNS_ADDRLIST	1
+#define	DNS_MAPDLIST	2
+
+static int
+dns_netdb_aliases(from_list, to_list, aliaspp, type, count, af_type)
+	char	**from_list, **to_list,	**aliaspp;
+	int	type, *count, af_type;
+{
+	char		*fstr;
+	int		cnt = 0;
+	size_t		len;
+
+	*count = 0;
+	if ((char *)to_list >= *aliaspp)
+		return (NSS_STR_PARSE_ERANGE);
+
+	for (fstr = from_list[cnt]; fstr != NULL; fstr = from_list[cnt]) {
+		if (type == DNS_ALIASES)
+			len = strlen(fstr) + 1;
+		else
+			len = (af_type == AF_INET) ? sizeof (struct in_addr)
+						: sizeof (struct in6_addr);
+		*aliaspp -= len;
+		to_list[cnt] = *aliaspp;
+		if (*aliaspp <= (char *)&to_list[cnt+1])
+			return (NSS_STR_PARSE_ERANGE);
+		if (type == DNS_MAPDLIST) {
+			struct in6_addr *addr6p = (struct in6_addr *) *aliaspp;
+
+			(void) memset(addr6p, '\0', sizeof (struct in6_addr));
+			(void) memcpy(&addr6p->s6_addr[12], fstr,
+					sizeof (struct in_addr));
+			addr6p->s6_addr[10] = 0xffU;
+			addr6p->s6_addr[11] = 0xffU;
+			++cnt;
+		} else {
+			(void) memcpy (*aliaspp, fstr, len);
+			++cnt;
+		}
+	}
+	to_list[cnt] = NULL;
+
+	*count = cnt;
+	if (cnt == 0)
+		return (NSS_STR_PARSE_PARSE);
+
+	return (NSS_STR_PARSE_SUCCESS);
+}
+
+
+int
+ent2result(he, argp, af_type)
+	struct hostent		*he;
+	nss_XbyY_args_t		*argp;
+	int			af_type;
+{
+	char		*buffer, *limit;
+	int		buflen = argp->buf.buflen;
+	int		ret, count;
+	size_t len;
+	struct hostent 	*host;
+	struct in_addr	*addrp;
+	struct in6_addr	*addrp6;
+
+	limit = argp->buf.buffer + buflen;
+	host = (struct hostent *) argp->buf.result;
+	buffer = argp->buf.buffer;
+
+	/* h_addrtype and h_length */
+	host->h_addrtype = af_type;
+	host->h_length = (af_type == AF_INET) ? sizeof (struct in_addr)
+					: sizeof (struct in6_addr);
+
+	/* h_name */
+	len = strlen(he->h_name) + 1;
+	host->h_name = buffer;
+	if (host->h_name + len >= limit)
+		return (NSS_STR_PARSE_ERANGE);
+	(void) memcpy(host->h_name, he->h_name, len);
+	buffer += len;
+
+	/* h_addr_list */
+	if (af_type == AF_INET) {
+		addrp = (struct in_addr *) ROUND_DOWN(limit, sizeof (*addrp));
+		host->h_addr_list = (char **)
+				ROUND_UP(buffer, sizeof (char **));
+		ret = dns_netdb_aliases(he->h_addr_list, host->h_addr_list,
+			(char **)&addrp, DNS_ADDRLIST, &count, af_type);
+		if (ret != NSS_STR_PARSE_SUCCESS)
+			return (ret);
+		/* h_aliases */
+		host->h_aliases = host->h_addr_list + count + 1;
+		ret = dns_netdb_aliases(he->h_aliases, host->h_aliases,
+			(char **)&addrp, DNS_ALIASES, &count, af_type);
+	} else {
+		addrp6 = (struct in6_addr *)
+			ROUND_DOWN(limit, sizeof (*addrp6));
+		host->h_addr_list = (char **)
+			ROUND_UP(buffer, sizeof (char **));
+		if (he->h_addrtype == AF_INET && af_type == AF_INET6) {
+			ret = dns_netdb_aliases(he->h_addr_list,
+				host->h_addr_list, (char **)&addrp6,
+				DNS_MAPDLIST, &count, af_type);
+		} else {
+			ret = dns_netdb_aliases(he->h_addr_list,
+				host->h_addr_list, (char **)&addrp6,
+				DNS_ADDRLIST, &count, af_type);
+		}
+		if (ret != NSS_STR_PARSE_SUCCESS)
+			return (ret);
+		/* h_aliases */
+		host->h_aliases = host->h_addr_list + count + 1;
+		ret = dns_netdb_aliases(he->h_aliases, host->h_aliases,
+			(char **)&addrp6, DNS_ALIASES, &count, af_type);
+	}
+	if (ret == NSS_STR_PARSE_PARSE)
+		ret = NSS_STR_PARSE_SUCCESS;
+
+	return (ret);
+}
+
+
+nss_backend_t *
+_nss_dns_constr(dns_backend_op_t ops[], int n_ops)
+{
+	dns_backend_ptr_t	be;
+
+	if ((be = (dns_backend_ptr_t) malloc(sizeof (*be))) == 0)
+		return (0);
+
+	be->ops = ops;
+	be->n_ops = n_ops;
+	return ((nss_backend_t *) be);
+}
diff --git a/usr/src/lib/nsswitch/dns/common/dns_common.h b/usr/src/lib/nsswitch/dns/common/dns_common.h
new file mode 100644
index 0000000000..7861cbb683
--- /dev/null
+++ b/usr/src/lib/nsswitch/dns/common/dns_common.h
@@ -0,0 +1,88 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License, Version 1.0 only
+ * (the "License").  You may not use this file except in compliance
+ * with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or http://www.opensolaris.org/os/licensing.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+/*
+ * Copyright (c) 1993, 1998-1999 by Sun Microsystems, Inc.
+ * All rights reserved.
+ *
+ * Common code and structures used by name-service-switch "dns" backends.
+ */
+
+#ifndef _DNS_COMMON_H
+#define	_DNS_COMMON_H
+
+#pragma ident	"%Z%%M%	%I%	%E% SMI"
+
+#include <stdio.h>
+#include <ctype.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <netdb.h>
+#include <strings.h>
+#include <thread.h>
+#include <arpa/nameser.h>
+#include <resolv.h>
+#include <syslog.h>
+#include <nsswitch.h>
+#include <nss_dbdefs.h>
+#include <stdlib.h>
+#include <signal.h>
+
+#ifdef	__cplusplus
+extern "C" {
+#endif
+
+typedef struct dns_backend *dns_backend_ptr_t;
+typedef nss_status_t (*dns_backend_op_t)(dns_backend_ptr_t, void *);
+
+struct dns_backend {
+	dns_backend_op_t	*ops;
+	nss_dbop_t		n_ops;
+};
+
+/* multithreaded libresolv2 related functions and variables */
+extern void	(*set_no_hosts_fallback)(void);
+extern void	(*unset_no_hosts_fallback)(void);
+extern struct __res_state	*(*set_res_retry)();
+extern int	(*enable_mt)();
+extern int	(*disable_mt)();
+extern int	*(*get_h_errno)();
+extern int	(*override_retry)(int);
+extern void	switch_resolver_setup(int *, sigset_t *, int *);
+extern void	switch_resolver_reset(int, sigset_t, int);
+extern mutex_t	one_lane;
+
+extern int _thr_sigsetmask(int, const sigset_t *, sigset_t *);
+extern int _mutex_lock(mutex_t *);
+extern int _mutex_unlock(mutex_t *);
+extern const char *inet_ntop(int, const void *, char *, size_t);
+
+extern int ent2result(struct hostent *, nss_XbyY_args_t *, int);
+
+nss_backend_t *_nss_dns_constr(dns_backend_op_t *, int);
+extern	nss_status_t _herrno2nss(int);
+
+#ifdef	__cplusplus
+}
+#endif
+
+#endif /* _DNS_COMMON_H */
diff --git a/usr/src/lib/nsswitch/dns/common/dns_mt.c b/usr/src/lib/nsswitch/dns/common/dns_mt.c
new file mode 100644
index 0000000000..7e236c40eb
--- /dev/null
+++ b/usr/src/lib/nsswitch/dns/common/dns_mt.c
@@ -0,0 +1,312 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License, Version 1.0 only
+ * (the "License").  You may not use this file except in compliance
+ * with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or http://www.opensolaris.org/os/licensing.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+/*
+ * Copyright (c) 1993, 1998-2001 by Sun Microsystems, Inc.
+ * All rights reserved.
+ */
+
+#pragma ident	"%Z%%M%	%I%	%E% SMI"
+
+/*
+ * dns_mt.c
+ *
+ * This file contains all the MT related routines for the DNS backend.
+ */
+
+#include "dns_common.h"
+#include <dlfcn.h>
+
+/*
+ * If the DNS name service switch routines are used in a binary that depends
+ * on an older libresolv (libresolv.so.1, say), then having nss_dns.so.1 or
+ * libnss_dns.a depend on a newer libresolv (libresolv.so.2) will cause
+ * relocation problems. In particular, copy relocation of the _res structure
+ * (which changes in size from libresolv.so.1 to libresolv.so.2) could
+ * cause corruption, and result in a number of strange problems, including
+ * core dumps. Hence, we check if a libresolv is already loaded.
+ */
+
+#pragma init(_nss_dns_init)
+static void	_nss_dns_init(void);
+
+extern struct hostent *res_gethostbyname(const char *);
+#pragma weak	res_gethostbyname
+
+#define		RES_SET_NO_HOSTS_FALLBACK	"__res_set_no_hosts_fallback"
+extern void	__res_set_no_hosts_fallback(void);
+#pragma weak	__res_set_no_hosts_fallback
+
+#define		RES_UNSET_NO_HOSTS_FALLBACK	"__res_unset_no_hosts_fallback"
+extern void	__res_unset_no_hosts_fallback(void);
+#pragma weak	__res_unset_no_hosts_fallback
+
+#define		RES_GET_RES	"__res_get_res"
+extern struct __res_state	*__res_get_res(void);
+#pragma weak	__res_get_res
+
+#define		RES_ENABLE_MT			"__res_enable_mt"
+extern int	__res_enable_mt(void);
+#pragma weak	__res_enable_mt
+
+#define		RES_DISABLE_MT			"__res_disable_mt"
+extern int	__res_disable_mt(void);
+#pragma weak	__res_disable_mt
+
+#define		RES_GET_H_ERRNO			"__res_get_h_errno"
+extern int	*__res_get_h_errno();
+#pragma weak	__res_get_h_errno
+
+#define		__H_ERRNO			"__h_errno"
+extern int	*__h_errno(void);
+#pragma weak	__h_errno
+
+#define		RES_OVERRIDE_RETRY		"__res_override_retry"
+extern int	__res_override_retry(int);
+#pragma weak	__res_override_retry
+
+static void	__fallback_set_no_hosts(void);
+static int	*__fallback_h_errno(void);
+static int	__fallback_override_retry(int);
+static int	__is_mt_safe(void);
+
+void	(*set_no_hosts_fallback)(void) = __fallback_set_no_hosts;
+void	(*unset_no_hosts_fallback)(void) = __fallback_set_no_hosts;
+struct __res_state	*(*set_res_retry)() = 0;
+int	(*enable_mt)() = 0;
+int	(*disable_mt)() = 0;
+int	*(*get_h_errno)(void) = 0;
+int	(*override_retry)(int) = 0;
+
+/* Usually set from the Makefile */
+#ifndef	NSS_DNS_LIBRESOLV
+#define	NSS_DNS_LIBRESOLV	"libresolv.so.2"
+#endif
+
+/* From libresolv */
+extern	int	h_errno;
+
+mutex_t	one_lane = DEFAULTMUTEX;
+
+void
+_nss_dns_init(void)
+{
+	struct hostent	*(*f_hostent_ptr)();
+	void		*reslib, (*f_void_ptr)();
+
+	/* If no libresolv library, then load one */
+	if ((f_hostent_ptr = res_gethostbyname) == 0) {
+		if ((reslib =
+		dlopen(NSS_DNS_LIBRESOLV, RTLD_LAZY|RTLD_GLOBAL)) != 0) {
+			/* Turn off /etc/hosts fall back in libresolv */
+			if ((f_void_ptr = (void (*)(void))dlsym(reslib,
+				RES_SET_NO_HOSTS_FALLBACK)) != 0) {
+				set_no_hosts_fallback = f_void_ptr;
+			}
+			if ((f_void_ptr = (void (*)(void))dlsym(reslib,
+				RES_SET_NO_HOSTS_FALLBACK)) != 0) {
+				unset_no_hosts_fallback = f_void_ptr;
+			}
+			/* Set number of resolver retries */
+			if ((override_retry = (int (*)(int))dlsym(reslib,
+				RES_OVERRIDE_RETRY)) == 0) {
+				set_res_retry =
+				(struct __res_state *(*)(void))dlsym(reslib,
+					RES_GET_RES);
+				override_retry = __fallback_override_retry;
+			}
+			/*
+			 * Select h_errno retrieval function. A BIND 8.2.2
+			 * libresolv.so.2 will have __h_errno, a BIND 8.1.2
+			 * one will have __res_get_h_errno, and other
+			 * versions may have nothing at all.
+			 *
+			 * Also try to bind to the relevant MT enable/disable
+			 * functions which are also dependent on the version
+			 * of the BIND libresolv.so.2 being used.
+			 */
+			if ((get_h_errno = (int *(*)(void))dlsym(reslib,
+			    __H_ERRNO)) != 0) {
+				/* BIND 8.2.2 libresolv.so.2 is MT safe. */
+				enable_mt = __is_mt_safe;
+				disable_mt = __is_mt_safe;
+			} else {
+				if ((get_h_errno =
+				    (int *(*)(void))dlsym(reslib,
+					RES_GET_H_ERRNO)) == 0) {
+					get_h_errno = __fallback_h_errno;
+				}
+				/*
+				 * Pre-BIND 8.2.2 was not MT safe.  Try to
+				 * bind the MT enable/disable functions.
+				 */
+				if ((enable_mt = (int (*)(void))dlsym(reslib,
+				    RES_ENABLE_MT)) != 0 &&
+				    (disable_mt = (int (*)(void))dlsym(reslib,
+					RES_DISABLE_MT)) == 0) {
+					enable_mt = 0;
+				}
+			}
+		}
+	} else {
+		/* Libresolv already loaded */
+		if ((f_void_ptr = __res_set_no_hosts_fallback) != 0) {
+			set_no_hosts_fallback = f_void_ptr;
+		}
+		if ((f_void_ptr = __res_unset_no_hosts_fallback) != 0) {
+			unset_no_hosts_fallback = f_void_ptr;
+		}
+		if ((override_retry = __res_override_retry) == 0) {
+			set_res_retry = __res_get_res;
+			override_retry = __fallback_override_retry;
+		}
+		if ((get_h_errno = __h_errno) == 0 &&
+			(get_h_errno = __res_get_h_errno) == 0) {
+			get_h_errno = __fallback_h_errno;
+		}
+		if (get_h_errno == __h_errno) {
+			enable_mt = __is_mt_safe;
+			disable_mt = __is_mt_safe;
+		} else {
+			if ((enable_mt = __res_enable_mt) != 0 &&
+			    (disable_mt = __res_disable_mt) == 0) {
+				enable_mt = 0;
+			}
+		}
+	}
+}
+
+
+/*
+ *
+ * Integration of BIND 8.1.2 introduced two new Sun private functions,
+ * __res_enable_mt() and __res_disable_mt(), that enabled and disabled
+ * MT mode per-thread. These functions are in the private libresolv.so.2
+ * interface, and intended for use by nss_dns.so.1.
+ *
+ * BIND 8.2.2 removed the need for those two functions.  As similar
+ * functionality was provided in BIND further up the stack. However the
+ * functions remain to satisfy any application that directly called upon
+ * them.  Only, __res_enable_mt() was modified to return failure.
+ * Indicated by a non-zero return value.  So that those unconventional
+ * applications would not then presume that res_send() and friends are
+ * MT-safe, when in fact they are not.
+ *
+ * To prevent nss_dns from locking inappropriately __is_mt_safe() is
+ * called in place of __res_enable_mt() and __res_disable_mt() if BIND
+ * 8.2.2 libresolv.so.2 being used.  __is_mt_safe() returns success
+ * indicated by a return code of zero. Signifying that no locking is
+ * necessary.
+ *
+ * MT applications making calls to gethostby*_r() or getipnodeby*()
+ * linked to libresolv.so.1 or linked statically with pre-BIND 8.2.2
+ * libresolv.a, doubtful as we don't ship a static version, would require
+ * locking within the nsswitch back-end.  Hence the mechanism can not
+ * simply be removed.
+ *
+ */
+static int
+__is_mt_safe(void) {
+	return (0);
+}
+
+
+/*
+ * Return pointer to the global h_errno variable
+ */
+static int *
+__fallback_h_errno(void) {
+	return (&h_errno);
+}
+
+
+/*
+ * This function is called when the resolver library doesn't provide its
+ * own function to establish an override retry. If we can get a pointer
+ * to the per-thread _res (i.e., set_res_retry != 0), we set the retries
+ * directly, and return the previous number of retries. Otherwise, there's
+ * nothing to do.
+ */
+static int
+__fallback_override_retry(int retry) {
+	struct __res_state	*res;
+	int			old_retry = 0;
+
+	if (set_res_retry != 0) {
+		res = set_res_retry();
+		old_retry = res->retry;
+		res->retry = retry;
+	}
+	return (old_retry);
+}
+
+
+static void
+__fallback_set_no_hosts(void) {
+}
+
+
+/*
+ * Common code to enable/disable MT mode, set/unset no-/etc/hosts fallback,
+ * and to set the number of retries.
+ */
+void
+switch_resolver_setup(int *mt_disabled, sigset_t *oldmask, int *old_retry) {
+
+	/*
+	 * Try to enable MT mode. If that isn't possible, mask signals,
+	 * and mutex_lock.
+	 */
+	*mt_disabled = 1;
+	if (enable_mt == 0 || (*mt_disabled = (*enable_mt)()) != 0) {
+		sigset_t	newmask;
+		(void) sigfillset(&newmask);
+		_thr_sigsetmask(SIG_SETMASK, &newmask, oldmask);
+		_mutex_lock(&one_lane);
+	}
+
+	/*
+	 * Disable any fallback to /etc/hosts (or /etc/inet/ipnodes, when
+	 * libresolv knows about that file).
+	 */
+	(*set_no_hosts_fallback)();
+
+	/*
+	 * The NS switch wants to handle retries on its own.
+	 */
+	*old_retry = (*override_retry)(1);
+}
+
+
+void
+switch_resolver_reset(int mt_disabled, sigset_t oldmask, int old_retry) {
+
+	if (mt_disabled) {
+		_mutex_unlock(&one_lane);
+		_thr_sigsetmask(SIG_SETMASK, &oldmask, NULL);
+	} else {
+		(void) (*disable_mt)();
+	}
+
+	(*unset_no_hosts_fallback)();
+
+	(void) (*override_retry)(old_retry);
+}
diff --git a/usr/src/lib/nsswitch/dns/common/gethostent.c b/usr/src/lib/nsswitch/dns/common/gethostent.c
new file mode 100644
index 0000000000..38c8a44a3a
--- /dev/null
+++ b/usr/src/lib/nsswitch/dns/common/gethostent.c
@@ -0,0 +1,416 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License, Version 1.0 only
+ * (the "License").  You may not use this file except in compliance
+ * with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or http://www.opensolaris.org/os/licensing.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+/*
+ * Copyright (c) 1993, 1998-2000 by Sun Microsystems, Inc.
+ * All rights reserved.
+ */
+
+#pragma ident	"%Z%%M%	%I%	%E% SMI"
+
+/*
+ * gethostent.c
+ *
+ * In order to avoid duplicating libresolv code here, and since libresolv.so.2
+ * provides res_-equivalents of the getXbyY and {set,get}Xent, lets call
+ * re_gethostbyaddr() and so on from this file. Among other things, this
+ * should help us avoid problems like the one described in bug 1264386,
+ * where the internal getanswer() acquired new functionality in BIND 4.9.3,
+ * but the local copy of getanswer() in this file wasn't updated, so that new
+ * functionality wasn't available to the name service switch.
+ */
+
+#define	gethostbyaddr	res_gethostbyaddr
+#define	gethostbyname	res_gethostbyname
+#define	gethostbyname2	res_gethostbyname2
+#define	sethostent	res_sethostent
+#define	endhostent	res_endhostent
+
+#include "dns_common.h"
+
+extern char *inet_ntoa(struct in_addr in);
+
+struct hostent *_gethostbyname(int *h_errnop, const char *name);
+static struct hostent *_gethostbyaddr(int *h_errnop, const char *addr,
+    int len, int type);
+struct hostent *_nss_dns_gethostbyname2(int *h_errnop, const char *name);
+
+#pragma weak	res_gethostbyname
+#pragma weak	res_gethostbyname2
+#pragma weak	res_gethostbyaddr
+#pragma weak	res_sethostent
+#pragma weak	res_endhostent
+
+nss_backend_t *_nss_dns_constr(dns_backend_op_t ops[], int n_ops);
+nss_status_t __nss_dns_getbyaddr(dns_backend_ptr_t, void *);
+
+typedef union {
+	long al;
+	char ac;
+} align;
+
+/*
+ * Internet Name Domain Server (DNS) only implementation.
+ */
+static struct hostent *
+_gethostbyaddr(int *h_errnop, const char *addr, int len, int type)
+{
+	struct hostent	*hp;
+
+	hp = gethostbyaddr(addr, len, type);
+	*h_errnop = *get_h_errno();
+	return (hp);
+}
+
+struct hostent *
+_nss_dns_gethostbyname2(int *h_errnop, const char *name)
+{
+	struct hostent *hp;
+
+	hp = gethostbyname2(name, AF_INET6);
+	*h_errnop = *get_h_errno();
+	return (hp);
+}
+
+struct hostent *
+_gethostbyname(int *h_errnop, const char *name)
+{
+	struct hostent *hp;
+
+	hp = gethostbyname(name);
+	*h_errnop = *get_h_errno();
+	return (hp);
+}
+
+static void
+_sethostent(errp, stayopen)
+	nss_status_t	*errp;
+	int		stayopen;
+{
+	int	ret;
+
+	ret = sethostent(stayopen);
+	if (ret == 0)
+		*errp = NSS_SUCCESS;
+	else
+		*errp = NSS_UNAVAIL;
+}
+
+static void
+_endhostent(errp)
+	nss_status_t	*errp;
+{
+	int	ret;
+
+	ret = endhostent();
+	if (ret == 0)
+		*errp = NSS_SUCCESS;
+	else
+		*errp = NSS_UNAVAIL;
+}
+
+
+/*ARGSUSED*/
+static nss_status_t
+getbyname(be, a)
+	dns_backend_ptr_t	be;
+	void			*a;
+{
+	struct hostent	*he;
+	nss_XbyY_args_t	*argp = (nss_XbyY_args_t *)a;
+	int		ret, mt_disabled;
+	int		old_retry;
+	sigset_t	oldmask;
+
+	switch_resolver_setup(&mt_disabled, &oldmask, &old_retry);
+
+	he = _gethostbyname(&argp->h_errno, argp->key.name);
+	if (he != NULL) {
+		ret = ent2result(he, a, AF_INET);
+		if (ret == NSS_STR_PARSE_SUCCESS) {
+			argp->returnval = argp->buf.result;
+		} else {
+			argp->h_errno = HOST_NOT_FOUND;
+			if (ret == NSS_STR_PARSE_ERANGE) {
+				argp->erange = 1;
+			}
+		}
+	}
+
+	switch_resolver_reset(mt_disabled, oldmask, old_retry);
+
+	return (_herrno2nss(argp->h_errno));
+}
+
+
+
+/*ARGSUSED*/
+static nss_status_t
+getbyaddr(be, a)
+	dns_backend_ptr_t	be;
+	void			*a;
+{
+	return (__nss_dns_getbyaddr(be, a));
+}
+
+
+/*
+ * Exposing a DNS backend specific interface so that it doesn't conflict
+ * with other getbyaddr() routines from other switch backends.
+ */
+nss_status_t
+__nss_dns_getbyaddr(be, a)
+	dns_backend_ptr_t	be;
+	void			*a;
+{
+	size_t	n;
+	struct hostent	*he, *he2;
+	nss_XbyY_args_t	*argp = (nss_XbyY_args_t *)a;
+	int		ret, save_h_errno, mt_disabled;
+	char		**ans, hbuf[MAXHOSTNAMELEN];
+	char		dst[INET6_ADDRSTRLEN];
+	struct in_addr	unmapv4;
+	sigset_t	oldmask;
+	int		af, addrlen;
+	void		*addrp;
+	int		old_retry;
+
+	switch_resolver_setup(&mt_disabled, &oldmask, &old_retry);
+
+	if (IN6_IS_ADDR_V4MAPPED((struct in6_addr *)argp->key.hostaddr.addr)) {
+		addrp = &unmapv4;
+		addrlen = sizeof (unmapv4);
+		af = AF_INET;
+		memcpy(addrp, &argp->key.hostaddr.addr[12], addrlen);
+	} else {
+		addrp = (void *)argp->key.hostaddr.addr;
+		addrlen = argp->key.hostaddr.len;
+		af = argp->key.hostaddr.type;
+	}
+	he = _gethostbyaddr(&argp->h_errno, addrp, addrlen, af);
+
+	if (he != NULL) {
+		if (strlen(he->h_name) >= MAXHOSTNAMELEN)
+			ret = NSS_STR_PARSE_ERANGE;
+		else {
+			/* save a copy of the (alleged) hostname */
+			(void) strcpy(hbuf, he->h_name);
+			n = strlen(hbuf);
+			if (n < MAXHOSTNAMELEN-1 && hbuf[n-1] != '.') {
+				(void) strcat(hbuf, ".");
+			}
+			ret = ent2result(he, a, argp->key.hostaddr.type);
+			save_h_errno = argp->h_errno;
+		}
+		if (ret == NSS_STR_PARSE_SUCCESS) {
+			/*
+			 * check to make sure by doing a forward query
+			 * We use _gethostbyname() to avoid the stack, and
+			 * then we throw the result from argp->h_errno away,
+			 * becase we don't care.  And besides you want the
+			 * return code from _gethostbyaddr() anyway.
+			 */
+
+			if (af == AF_INET)
+				he2 = _gethostbyname(&argp->h_errno, hbuf);
+			else
+				he2 = _nss_dns_gethostbyname2(&argp->h_errno,
+					hbuf);
+			if (he2 != (struct hostent *)NULL) {
+
+				/* until we prove name and addr match */
+				argp->h_errno = HOST_NOT_FOUND;
+				for (ans = he2->h_addr_list; *ans; ans++)
+					if (memcmp(*ans, addrp,	addrlen) ==
+						0) {
+					argp->h_errno = save_h_errno;
+					argp->returnval = argp->buf.result;
+					break;
+						}
+			} else {
+
+				/*
+				 * What to do if _gethostbyname() fails ???
+				 * We assume they are doing something stupid
+				 * like registering addresses but not names
+				 * (some people actually think that provides
+				 * some "security", through obscurity).  So for
+				 * these poor lost souls, because we can't
+				 * PROVE spoofing and because we did try (and
+				 * we don't want a bug filed on this), we let
+				 * this go.  And return the name from byaddr.
+				 */
+				argp->h_errno = save_h_errno;
+				argp->returnval = argp->buf.result;
+			}
+			/* we've been spoofed, make sure to log it. */
+			if (argp->h_errno == HOST_NOT_FOUND) {
+				if (argp->key.hostaddr.type == AF_INET)
+		syslog(LOG_NOTICE, "gethostbyaddr: %s != %s",
+		hbuf, inet_ntoa(*(struct in_addr *)argp->key.hostaddr.addr));
+				else
+		syslog(LOG_NOTICE, "gethostbyaddr: %s != %s",
+		hbuf, inet_ntop(AF_INET6, (void *) argp->key.hostaddr.addr,
+		dst, sizeof (dst)));
+			}
+		} else {
+			argp->h_errno = HOST_NOT_FOUND;
+			if (ret == NSS_STR_PARSE_ERANGE) {
+				argp->erange = 1;
+			}
+		}
+	}
+
+	switch_resolver_reset(mt_disabled, oldmask, old_retry);
+
+	return (_herrno2nss(argp->h_errno));
+}
+
+
+/*ARGSUSED*/
+static nss_status_t
+_nss_dns_getent(be, args)
+	dns_backend_ptr_t	be;
+	void			*args;
+{
+	return (NSS_UNAVAIL);
+}
+
+
+/*ARGSUSED*/
+static nss_status_t
+_nss_dns_setent(be, dummy)
+	dns_backend_ptr_t	be;
+	void			*dummy;
+{
+	nss_status_t	errp;
+
+	sigset_t	oldmask, newmask;
+	int		mt_disabled = 1;
+
+	/*
+	 * Try to enable MT; if not, we have to single-thread libresolv
+	 * access
+	 */
+	if (enable_mt == 0 || (mt_disabled = (*enable_mt)()) != 0) {
+		(void) sigfillset(&newmask);
+		_thr_sigsetmask(SIG_SETMASK, &newmask, &oldmask);
+		_mutex_lock(&one_lane);
+	}
+
+	_sethostent(&errp, 1);
+
+	if (mt_disabled) {
+		_mutex_unlock(&one_lane);
+		_thr_sigsetmask(SIG_SETMASK, &oldmask, NULL);
+	} else {
+		(void) (*disable_mt)();
+	}
+
+	return (errp);
+}
+
+
+/*ARGSUSED*/
+static nss_status_t
+_nss_dns_endent(be, dummy)
+	dns_backend_ptr_t	be;
+	void			*dummy;
+{
+	nss_status_t	errp;
+
+	sigset_t	oldmask, newmask;
+	int		mt_disabled = 1;
+
+	/*
+	 * Try to enable MT; if not, we have to single-thread libresolv
+	 * access
+	 */
+	if (enable_mt == 0 || (mt_disabled = (*enable_mt)()) != 0) {
+		(void) sigfillset(&newmask);
+		_thr_sigsetmask(SIG_SETMASK, &newmask, &oldmask);
+		_mutex_lock(&one_lane);
+	}
+
+	_endhostent(&errp);
+
+	if (mt_disabled) {
+		_mutex_unlock(&one_lane);
+		_thr_sigsetmask(SIG_SETMASK, &oldmask, NULL);
+	} else {
+		(void) (*disable_mt)();
+	}
+
+	return (errp);
+}
+
+
+/*ARGSUSED*/
+static nss_status_t
+_nss_dns_destr(be, dummy)
+	dns_backend_ptr_t	be;
+	void			*dummy;
+{
+	nss_status_t	errp;
+
+	if (be != 0) {
+		/* === Should change to invoke ops[ENDENT] ? */
+		sigset_t	oldmask, newmask;
+		int		mt_disabled = 1;
+
+		if (enable_mt == 0 || (mt_disabled = (*enable_mt)()) != 0) {
+			(void) sigfillset(&newmask);
+			_thr_sigsetmask(SIG_SETMASK, &newmask, &oldmask);
+			_mutex_lock(&one_lane);
+		}
+
+		_endhostent(&errp);
+
+		if (mt_disabled) {
+			_mutex_unlock(&one_lane);
+			_thr_sigsetmask(SIG_SETMASK, &oldmask, NULL);
+		} else {
+			(void) (*disable_mt)();
+		}
+
+		free(be);
+	}
+	return (NSS_SUCCESS);   /* In case anyone is dumb enough to check */
+}
+
+
+static dns_backend_op_t host_ops[] = {
+	_nss_dns_destr,
+	_nss_dns_endent,
+	_nss_dns_setent,
+	_nss_dns_getent,
+	getbyname,
+	getbyaddr,
+};
+
+/*ARGSUSED*/
+nss_backend_t *
+_nss_dns_hosts_constr(dummy1, dummy2, dummy3)
+	const char	*dummy1, *dummy2, *dummy3;
+{
+	return (_nss_dns_constr(host_ops,
+		sizeof (host_ops) / sizeof (host_ops[0])));
+}
diff --git a/usr/src/lib/nsswitch/dns/common/gethostent6.c b/usr/src/lib/nsswitch/dns/common/gethostent6.c
new file mode 100644
index 0000000000..e92ce6a356
--- /dev/null
+++ b/usr/src/lib/nsswitch/dns/common/gethostent6.c
@@ -0,0 +1,534 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License, Version 1.0 only
+ * (the "License").  You may not use this file except in compliance
+ * with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or http://www.opensolaris.org/os/licensing.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+/*
+ * Copyright 1993-2000, 2003 Sun Microsystems, Inc.  All rights reserved.
+ * Use is subject to license terms.
+ *
+ *	gethostent6.c
+ */
+
+#pragma ident	"%Z%%M%	%I%	%E% SMI"
+
+/*
+ * This is the DNS backend for IPv6 addresses.
+ * getbyname() is a local routine, but getbyaddr() actually shares the
+ * same codes as the one in gethostent.c.
+ */
+
+#define	endhostent	res_endhostent
+
+#include <malloc.h>
+#include <stddef.h>
+#include <string.h>
+#include "dns_common.h"
+
+/*
+ * If the DNS name service switch routines are used in a binary that depends
+ * on an older libresolv (libresolv.so.1, say), then having nss_dns.so.1 or
+ * libnss_dns.a depend on a newer libresolv (libresolv.so.2) will cause
+ * relocation problems. In particular, copy relocation of the _res structure
+ * (which changes in size from libresolv.so.1 to libresolv.so.2) could
+ * cause corruption, and result in a number of strange problems, including
+ * core dumps. Hence, we check if a libresolv is already loaded.
+ */
+
+
+#pragma weak	res_endhostent
+
+extern struct hostent *_gethostbyname(int *, const char *);
+extern struct hostent *_nss_dns_gethostbyname2(int *, const char *);
+
+typedef union {
+	long al;
+	char ac;
+} align;
+
+
+static void
+_endhostent(errp)
+	nss_status_t	*errp;
+{
+	int	ret;
+
+	ret = endhostent();
+	if (ret == 0)
+		*errp = NSS_SUCCESS;
+	else
+		*errp = NSS_UNAVAIL;
+}
+
+
+#ifdef	RNDUP
+#undef	RNDUP
+#endif
+#define	RNDUP(x)	((1 + (((x)-1)/sizeof (void *))) * sizeof (void *))
+
+#ifdef	PTROFF
+#undef	PTROFF
+#endif
+#define	PTROFF(p, o)	(((o) == 0) ? 0 : (void *)((char *)(p) + (o)))
+
+
+/*
+ * Make a copy of h->h_name.
+ */
+static char *
+cloneName(struct hostent *h, int *outerr) {
+
+	char	*name;
+	int	len;
+	int	error, *errp;
+
+	if (outerr)
+		errp = outerr;
+	else
+		errp = &error;
+
+	if (h == 0 || h->h_name == 0) {
+		*errp = 0;
+		return (0);
+	}
+
+	len = strlen(h->h_name);
+
+	if ((name = malloc(len+1)) == 0) {
+		*errp = 1;
+		return (0);
+	}
+
+	memcpy(name, h->h_name, len+1);
+
+	*errp = 0;
+	return (name);
+}
+
+
+/*
+ * Copy the h->h_addr_list[] array to a new array, and append the
+ * moreAddrs[] list. If h->h_addr_list[] contains IPv4 addresses,
+ * convert them to v4 mapped IPv6 addresses.
+ *
+ * Note: The pointers to the addresses in the moreAddrs[] array are copied,
+ *       but not the IP addresses themselves.
+ */
+struct in6_addr **
+cloneAddrList(struct hostent *h, struct in6_addr **moreAddrs, int *outerr) {
+
+	struct in6_addr	**addrArray, *addrList;
+	int		domap, addrlen, i, j, addrCount, moreAddrCount = 0;
+
+	int	error, *errp;
+
+	if (outerr)
+		errp = outerr;
+	else
+		errp = &error;
+
+	if (h == 0 || h->h_addr_list == 0) {
+		*errp = 0;
+		return (0);
+	}
+
+	/* Should we map v4 to IPv6 ? */
+	domap = (h->h_length == sizeof (struct in_addr)) &&
+		(h->h_addrtype == AF_INET);
+
+	/* If mapping, make sure we allocate enough memory for addresses */
+	addrlen = h->h_length;
+	if (domap && addrlen < sizeof (struct in6_addr))
+		addrlen = sizeof (struct in6_addr);
+
+	for (addrCount = 0; h->h_addr_list[addrCount]; addrCount++);
+
+	if (moreAddrs != 0) {
+		for (moreAddrCount = 0; moreAddrs[moreAddrCount];
+			moreAddrCount++);
+	}
+
+	if ((addrArray = malloc((addrCount+moreAddrCount+1)*sizeof (addrList) +
+				addrCount*addrlen)) == 0) {
+		*errp = 1;
+		return (0);
+	}
+
+	addrList = PTROFF(addrArray, (addrCount+moreAddrCount+1) *
+					sizeof (addrList));
+
+	for (i = 0; i < addrCount; i++) {
+		addrArray[i] = addrList;
+		if (domap) {
+			IN6_INADDR_TO_V4MAPPED(
+			(struct in_addr *)h->h_addr_list[i], addrArray[i]);
+		} else {
+			memcpy(addrArray[i], h->h_addr_list[i], addrlen);
+		}
+		addrList = PTROFF(addrList, addrlen);
+	}
+
+	for (j = 0; j < moreAddrCount; j++, i++) {
+		addrArray[i] = moreAddrs[j];
+	}
+
+	/* Last pointer should be NULL */
+	addrArray[i] = 0;
+
+	*errp = 0;
+	return (addrArray);
+}
+
+
+/*
+ * Create a new alias array that is is a copy of h->h_aliases[] plus
+ * the aliases in mergeAliases[] which aren't duplicates of any alias
+ * in h->h_aliases[].
+ *
+ * Note 1: Only the string pointers (NOT the strings) in the mergeAliases[]
+ *         array are copied.
+ *
+ * Note 2: The duplicate aliases in mergeAliases[] are replaced by NULL
+ *         pointers.
+ */
+static char **
+cloneAliasList(struct hostent *h, char **mergeAliases, int *outerr) {
+
+	char	**aliasArray, *aliasList;
+	int	i, j, k, aliasCount, mergeAliasCount = 0, realMac = 0;
+	int	stringSize = 0;
+	int	error, *errp;
+
+	if (outerr)
+		errp = outerr;
+	else
+		errp = &error;
+
+
+	if (h == 0 || h->h_aliases == 0) {
+		*errp = 0;
+		return (0);
+	}
+
+	for (aliasCount = 0; h->h_aliases[aliasCount]; aliasCount++) {
+		stringSize += RNDUP(strlen(h->h_aliases[aliasCount])+1);
+	}
+
+	if (mergeAliases != 0) {
+		for (; mergeAliases[mergeAliasCount]; mergeAliasCount++) {
+			int	countThis = 1;
+			/* Skip duplicates */
+			for (j = 0; j < aliasCount; j++) {
+				if (strcmp(mergeAliases[mergeAliasCount],
+						h->h_aliases[j]) == 0) {
+					countThis = 0;
+					break;
+				}
+			}
+			if (countThis)
+				realMac++;
+			else
+				mergeAliases[mergeAliasCount] = 0;
+		}
+	}
+
+	if ((aliasArray = malloc((aliasCount+realMac+1)*sizeof (char **)+
+				stringSize)) == 0) {
+		*errp = 1;
+		return (0);
+	}
+
+	aliasList = PTROFF(aliasArray,
+				(aliasCount+realMac+1)*sizeof (char **));
+	for (i = 0; i < aliasCount; i++) {
+		int	len = strlen(h->h_aliases[i]);
+		aliasArray[i] = aliasList;
+		memcpy(aliasArray[i], h->h_aliases[i], len+1);
+		aliasList = PTROFF(aliasList, RNDUP(len+1));
+	}
+
+	for (j = 0; j < mergeAliasCount; j++) {
+		if (mergeAliases[j] != 0) {
+			aliasArray[i++] = mergeAliases[j];
+		}
+	}
+
+	aliasArray[i] = 0;
+
+	*errp = 0;
+	return (aliasArray);
+}
+
+
+static nss_status_t
+getbyname(be, a)
+	dns_backend_ptr_t	be;
+	void			*a;
+{
+	struct hostent	*he = NULL;
+	nss_XbyY_args_t	*argp = (nss_XbyY_args_t *)a;
+	int		ret, mt_disabled;
+	sigset_t	oldmask;
+	int		converr = 0, gotv6 = 0;
+	struct hostent	v6he;
+	char		*v6Name = 0;
+	struct in6_addr	**v6Addrs = 0, **mergeAddrs = 0;
+	char		**v6Aliases = 0, **mergeAliases = 0;
+	int		v6_h_errno;
+	int		old_retry;
+	int		af = argp->key.ipnode.af_family;
+	int		flags = argp->key.ipnode.flags;
+
+	switch_resolver_setup(&mt_disabled, &oldmask, &old_retry);
+
+	/* Now get the AAAA records */
+	if (af == AF_INET6)
+		he = _nss_dns_gethostbyname2(&argp->h_errno,
+					argp->key.ipnode.name);
+	if (he != NULL) {
+		/*
+		 * pointer in "he" is part of a static pthread key in libresolv
+		 * It should be treated as read only.
+		 * So clone a copy first.
+		 */
+		v6Name = cloneName(he, &converr);
+		if (converr) {
+			argp->h_errno = HOST_NOT_FOUND;
+			argp->erange = 1;
+			switch_resolver_reset(mt_disabled, oldmask, old_retry);
+			return (_herrno2nss(argp->h_errno));
+		}
+		v6Addrs = cloneAddrList(he, 0, &converr);
+		if (converr) {
+			if (v6Name != 0)
+				free(v6Name);
+			argp->h_errno = HOST_NOT_FOUND;
+			argp->erange = 1;
+			switch_resolver_reset(mt_disabled, oldmask, old_retry);
+			return (_herrno2nss(argp->h_errno));
+		}
+		v6Aliases = cloneAliasList(he, 0, &converr);
+		if (converr) {
+			if (v6Name != 0)
+				free(v6Name);
+			if (v6Addrs != 0)
+				free(v6Addrs);
+			argp->h_errno = HOST_NOT_FOUND;
+			argp->erange = 1;
+			switch_resolver_reset(mt_disabled, oldmask, old_retry);
+			return (_herrno2nss(argp->h_errno));
+		}
+		v6_h_errno = argp->h_errno;
+		gotv6 = 1;
+	}
+
+	/*
+	 * The conditions to search "A" records:
+	 * 1. af is AF_INET
+	 * 2. if af is AF_INET6
+	 *    then flags are either
+	 *	1) (AI_ALL | AI_V4MAPPED) or
+	 *	2) AI_V4MAPPED and he == NULL
+	 *	    (No V6 addresses found or no search for V6 at all)
+	 */
+
+	/* Get the A records, and store the information */
+	if ((af == AF_INET) ||
+	    ((af == AF_INET6) &&
+		((flags & (AI_ALL | AI_V4MAPPED)) ||
+		((flags & AI_V4MAPPED) && he == NULL))))
+		he = _gethostbyname(&argp->h_errno, argp->key.ipnode.name);
+	else
+		he = NULL;
+
+	/* Merge the results */
+	if (he != NULL) {
+		mergeAddrs = cloneAddrList(he, v6Addrs, &converr);
+		if (converr) {
+			if (v6Name != 0)
+				free(v6Name);
+			if (v6Addrs != 0)
+				free(v6Addrs);
+			if (v6Aliases != 0)
+				free(v6Aliases);
+			argp->h_errno = HOST_NOT_FOUND;
+			argp->erange = 1;
+			switch_resolver_reset(mt_disabled, oldmask,
+						old_retry);
+			return (_herrno2nss(argp->h_errno));
+		}
+		he->h_addr_list = (char **)mergeAddrs;
+
+		mergeAliases = cloneAliasList(he, v6Aliases, &converr);
+		if (converr) {
+			if (v6Name != 0)
+				free(v6Name);
+			if (v6Addrs != 0)
+				free(v6Addrs);
+			if (v6Aliases != 0)
+				free(v6Aliases);
+			if (mergeAddrs != 0)
+				free(mergeAddrs);
+			argp->h_errno = HOST_NOT_FOUND;
+			argp->erange = 1;
+			switch_resolver_reset(mt_disabled, oldmask,
+						old_retry);
+			return (_herrno2nss(argp->h_errno));
+		}
+		he->h_aliases = mergeAliases;
+
+		/* reset h_length, h_addrtype */
+		he->h_length = sizeof (struct in6_addr);
+		he->h_addrtype = AF_INET6;
+
+	} else if (gotv6) {
+		v6he.h_name = v6Name;
+		v6he.h_length = sizeof (struct in6_addr);
+		v6he.h_addrtype = AF_INET6;
+		v6he.h_addr_list = (char **)v6Addrs;
+		v6he.h_aliases = v6Aliases;
+		he = &v6he;
+		argp->h_errno = v6_h_errno;
+	}
+
+	if (he != 0) {
+		ret = ent2result(he, a, AF_INET6);
+		if (ret == NSS_STR_PARSE_SUCCESS) {
+			argp->returnval = argp->buf.result;
+		} else {
+			argp->h_errno = HOST_NOT_FOUND;
+			if (ret == NSS_STR_PARSE_ERANGE) {
+				argp->erange = 1;
+			}
+		}
+	}
+
+	if (v6Name != 0)
+		free(v6Name);
+	if (v6Addrs != 0)
+		free(v6Addrs);
+	if (v6Aliases != 0)
+		free(v6Aliases);
+	if (mergeAddrs != 0)
+		free(mergeAddrs);
+	if (mergeAliases != 0)
+		free(mergeAliases);
+
+	switch_resolver_reset(mt_disabled, oldmask, old_retry);
+
+	return (_herrno2nss(argp->h_errno));
+}
+
+
+extern nss_status_t __nss_dns_getbyaddr(dns_backend_ptr_t, void *);
+
+static nss_status_t
+getbyaddr(be, a)
+	dns_backend_ptr_t	be;
+	void			*a;
+{
+	/* uses the same getbyaddr from IPv4 */
+	return (__nss_dns_getbyaddr(be, a));
+}
+
+
+/*ARGSUSED*/
+static nss_status_t
+_nss_dns_getent(be, args)
+	dns_backend_ptr_t	be;
+	void			*args;
+{
+	return (NSS_UNAVAIL);
+}
+
+
+/*ARGSUSED*/
+static nss_status_t
+_nss_dns_setent(be, dummy)
+	dns_backend_ptr_t	be;
+	void			*dummy;
+{
+	/* XXXX not implemented at this point */
+	return (NSS_UNAVAIL);
+}
+
+
+/*ARGSUSED*/
+static nss_status_t
+_nss_dns_endent(be, dummy)
+	dns_backend_ptr_t	be;
+	void			*dummy;
+{
+	/* XXXX not implemented at this point */
+	return (NSS_UNAVAIL);
+}
+
+
+/*ARGSUSED*/
+static nss_status_t
+_nss_dns_destr(be, dummy)
+	dns_backend_ptr_t	be;
+	void			*dummy;
+{
+	nss_status_t	errp;
+
+	if (be != 0) {
+		/* === Should change to invoke ops[ENDENT] ? */
+		sigset_t	oldmask, newmask;
+		int		mt_disabled = 1;
+
+		if (enable_mt == 0 || (mt_disabled = (*enable_mt)()) != 0) {
+			(void) sigfillset(&newmask);
+			_thr_sigsetmask(SIG_SETMASK, &newmask, &oldmask);
+			_mutex_lock(&one_lane);
+		}
+
+		_endhostent(&errp);
+
+		if (mt_disabled) {
+			_mutex_unlock(&one_lane);
+			_thr_sigsetmask(SIG_SETMASK, &oldmask, NULL);
+		} else {
+			(void) (*disable_mt)();
+		}
+
+		free(be);
+	}
+	return (NSS_SUCCESS);   /* In case anyone is dumb enough to check */
+}
+
+
+
+static dns_backend_op_t ipnodes_ops[] = {
+	_nss_dns_destr,
+	_nss_dns_endent,
+	_nss_dns_setent,
+	_nss_dns_getent,
+	getbyname,
+	getbyaddr,
+};
+
+/*ARGSUSED*/
+nss_backend_t *
+_nss_dns_ipnodes_constr(dummy1, dummy2, dummy3)
+	const char	*dummy1, *dummy2, *dummy3;
+{
+	return (_nss_dns_constr(ipnodes_ops,
+		sizeof (ipnodes_ops) / sizeof (ipnodes_ops[0])));
+}
diff --git a/usr/src/lib/nsswitch/dns/common/mapfile-vers b/usr/src/lib/nsswitch/dns/common/mapfile-vers
new file mode 100644
index 0000000000..6e44ffe568
--- /dev/null
+++ b/usr/src/lib/nsswitch/dns/common/mapfile-vers
@@ -0,0 +1,46 @@
+#
+#ident	"%Z%%M%	%I%	%E% SMI"
+#
+# Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
+# Use is subject to license terms.
+#
+# CDDL HEADER START
+#
+# The contents of this file are subject to the terms of the
+# Common Development and Distribution License, Version 1.0 only
+# (the "License").  You may not use this file except in compliance
+# with the License.
+#
+# You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+# or http://www.opensolaris.org/os/licensing.
+# See the License for the specific language governing permissions
+# and limitations under the License.
+#
+# When distributing Covered Code, include this CDDL HEADER in each
+# file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+# If applicable, add the following below this CDDL HEADER, with the
+# fields enclosed by brackets "[]" replaced with your own identifying
+# information: Portions Copyright [yyyy] [name of copyright owner]
+#
+# CDDL HEADER END
+#
+# Generic interface definition for usr/src/lib/nsswitch/dns.
+#
+# For information regarding the establishment of versioned definitions see:
+#	The Linker and Libraries Manual (version 2.5 or greater)
+# This is part of the Developers Guide in the Answerbook.  Specifically refer
+# to Chapter 2 under section "Defining Additional Symbols" through section
+# "Reducing Symbol Scope", and Chapter 5 "Versioning".
+#
+# For specific OSNET rules for the modification (evolution) of these version
+# definitions see:
+#	Policy for Shared Library Version Names and Interface Definitions
+
+
+SUNWprivate_1.1 {
+	global:
+		_nss_dns_hosts_constr;
+		_nss_dns_ipnodes_constr;
+	local:
+		*;
+};
diff --git a/usr/src/lib/nsswitch/dns/i386/Makefile b/usr/src/lib/nsswitch/dns/i386/Makefile
new file mode 100644
index 0000000000..164288fc1d
--- /dev/null
+++ b/usr/src/lib/nsswitch/dns/i386/Makefile
@@ -0,0 +1,36 @@
+#
+# CDDL HEADER START
+#
+# The contents of this file are subject to the terms of the
+# Common Development and Distribution License, Version 1.0 only
+# (the "License").  You may not use this file except in compliance
+# with the License.
+#
+# You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+# or http://www.opensolaris.org/os/licensing.
+# See the License for the specific language governing permissions
+# and limitations under the License.
+#
+# When distributing Covered Code, include this CDDL HEADER in each
+# file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+# If applicable, add the following below this CDDL HEADER, with the
+# fields enclosed by brackets "[]" replaced with your own identifying
+# information: Portions Copyright [yyyy] [name of copyright owner]
+#
+# CDDL HEADER END
+#
+#
+# Copyright 1993,2001-2003 Sun Microsystems, Inc.  All rights reserved.
+# Use is subject to license terms.
+#
+# ident	"%Z%%M%	%I%	%E% SMI"
+#
+# lib/nsswitch/dns/i386/Makefile
+
+include		../Makefile.com
+
+LIBS =		$(DYNLIB1)
+
+include		../../Makefile.targ
+
+install:	all $(ROOTLIBS)
diff --git a/usr/src/lib/nsswitch/dns/sparc/Makefile b/usr/src/lib/nsswitch/dns/sparc/Makefile
new file mode 100644
index 0000000000..9ea99483e7
--- /dev/null
+++ b/usr/src/lib/nsswitch/dns/sparc/Makefile
@@ -0,0 +1,36 @@
+#
+# CDDL HEADER START
+#
+# The contents of this file are subject to the terms of the
+# Common Development and Distribution License, Version 1.0 only
+# (the "License").  You may not use this file except in compliance
+# with the License.
+#
+# You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+# or http://www.opensolaris.org/os/licensing.
+# See the License for the specific language governing permissions
+# and limitations under the License.
+#
+# When distributing Covered Code, include this CDDL HEADER in each
+# file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+# If applicable, add the following below this CDDL HEADER, with the
+# fields enclosed by brackets "[]" replaced with your own identifying
+# information: Portions Copyright [yyyy] [name of copyright owner]
+#
+# CDDL HEADER END
+#
+#
+# Copyright 1993,2001-2003 Sun Microsystems, Inc.  All rights reserved.
+# Use is subject to license terms.
+#
+# ident	"%Z%%M%	%I%	%E% SMI"
+#
+# lib/nsswitch/dns/sparc/Makefile
+
+include		../Makefile.com
+
+LIBS =		$(DYNLIB1)
+
+include		../../Makefile.targ
+
+install:	all $(ROOTLIBS)
diff --git a/usr/src/lib/nsswitch/dns/sparcv9/Makefile b/usr/src/lib/nsswitch/dns/sparcv9/Makefile
new file mode 100644
index 0000000000..dbcedcf28e
--- /dev/null
+++ b/usr/src/lib/nsswitch/dns/sparcv9/Makefile
@@ -0,0 +1,37 @@
+#
+# CDDL HEADER START
+#
+# The contents of this file are subject to the terms of the
+# Common Development and Distribution License, Version 1.0 only
+# (the "License").  You may not use this file except in compliance
+# with the License.
+#
+# You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+# or http://www.opensolaris.org/os/licensing.
+# See the License for the specific language governing permissions
+# and limitations under the License.
+#
+# When distributing Covered Code, include this CDDL HEADER in each
+# file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+# If applicable, add the following below this CDDL HEADER, with the
+# fields enclosed by brackets "[]" replaced with your own identifying
+# information: Portions Copyright [yyyy] [name of copyright owner]
+#
+# CDDL HEADER END
+#
+#
+#ident	"%Z%%M%	%I%	%E% SMI"
+#
+# Copyright (c) 1993,2001 by Sun Microsystems, Inc.
+# All rights reserved.
+#
+# lib/nsswitch/dns/sparcv9/Makefile
+
+include		../Makefile.com
+include		$(SRC)/lib/Makefile.lib.64
+
+LIBS =		$(DYNLIB1)
+
+include		../../Makefile.targ
+
+install:	all $(ROOT64DYNLIB)