Move getaddrinfo from 'posix' into 'nss'

getaddrinfo is an entry point for nss functionality.  This commit moves
it from 'sysdeps/posix' to 'nss', gets rid of the stub in 'posix', and
moves all associated tests as well.
Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>

1 files changed, 2625 insertions, 0 deletions

diff --git a/nss/getaddrinfo.c b/nss/getaddrinfo.c
new file mode 100644
index 0000000000..531124958d
--- /dev/null
+++ b/nss/getaddrinfo.c
@@ -0,0 +1,2625 @@
+/* Host and service name lookups using Name Service Switch modules.
+   Copyright (C) 1996-2023 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+/* The Inner Net License, Version 2.00
+
+  The author(s) grant permission for redistribution and use in source and
+binary forms, with or without modification, of the software and documentation
+provided that the following conditions are met:
+
+0. If you receive a version of the software that is specifically labelled
+   as not being for redistribution (check the version message and/or README),
+   you are not permitted to redistribute that version of the software in any
+   way or form.
+1. All terms of the all other applicable copyrights and licenses must be
+   followed.
+2. Redistributions of source code must retain the authors' copyright
+   notice(s), this list of conditions, and the following disclaimer.
+3. Redistributions in binary form must reproduce the authors' copyright
+   notice(s), this list of conditions, and the following disclaimer in the
+   documentation and/or other materials provided with the distribution.
+4. [The copyright holder has authorized the removal of this clause.]
+5. Neither the name(s) of the author(s) nor the names of its contributors
+   may be used to endorse or promote products derived from this software
+   without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY ITS AUTHORS AND CONTRIBUTORS ``AS IS'' AND ANY
+EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE FOR ANY
+DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+  If these license terms cause you a real problem, contact the author.  */
+
+/* This software is Copyright 1996 by Craig Metz, All Rights Reserved.  */
+
+#include <assert.h>
+#include <ctype.h>
+#include <errno.h>
+#include <ifaddrs.h>
+#include <netdb.h>
+#include <nss.h>
+#include <resolv/resolv-internal.h>
+#include <resolv/resolv_context.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdio_ext.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdint.h>
+#include <arpa/inet.h>
+#include <net/if.h>
+#include <netinet/in.h>
+#include <sys/socket.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/un.h>
+#include <sys/utsname.h>
+#include <unistd.h>
+#include <nsswitch.h>
+#include <libc-lock.h>
+#include <not-cancel.h>
+#include <nscd/nscd-client.h>
+#include <nscd/nscd_proto.h>
+#include <scratch_buffer.h>
+#include <inet/net-internal.h>
+
+/* Former AI_IDN_ALLOW_UNASSIGNED and AI_IDN_USE_STD3_ASCII_RULES
+   flags, now ignored.  */
+#define DEPRECATED_AI_IDN 0x300
+
+#if IS_IN (libc)
+# define feof_unlocked(fp) __feof_unlocked (fp)
+#endif
+
+struct gaih_service
+  {
+    const char *name;
+    int num;
+  };
+
+struct gaih_servtuple
+  {
+    int socktype;
+    int protocol;
+    int port;
+    bool set;
+  };
+
+
+struct gaih_typeproto
+  {
+    int socktype;
+    int protocol;
+    uint8_t protoflag;
+    bool defaultflag;
+    char name[8];
+  };
+
+struct gaih_result
+{
+  struct gaih_addrtuple *at;
+  char *canon;
+  char *h_name;
+  bool free_at;
+  bool got_ipv6;
+};
+
+/* Values for `protoflag'.  */
+#define GAI_PROTO_NOSERVICE	1
+#define GAI_PROTO_PROTOANY	2
+
+static const struct gaih_typeproto gaih_inet_typeproto[] =
+{
+  { 0, 0, 0, false, "" },
+  { SOCK_STREAM, IPPROTO_TCP, 0, true, "tcp" },
+  { SOCK_DGRAM, IPPROTO_UDP, 0, true, "udp" },
+#if defined SOCK_DCCP && defined IPPROTO_DCCP
+  { SOCK_DCCP, IPPROTO_DCCP, 0, false, "dccp" },
+#endif
+#ifdef IPPROTO_UDPLITE
+  { SOCK_DGRAM, IPPROTO_UDPLITE, 0, false, "udplite" },
+#endif
+#ifdef IPPROTO_SCTP
+  { SOCK_STREAM, IPPROTO_SCTP, 0, false, "sctp" },
+  { SOCK_SEQPACKET, IPPROTO_SCTP, 0, false, "sctp" },
+#endif
+  { SOCK_RAW, 0, GAI_PROTO_PROTOANY|GAI_PROTO_NOSERVICE, true, "raw" },
+  { 0, 0, 0, false, "" }
+};
+
+static const struct addrinfo default_hints =
+  {
+    .ai_flags = AI_DEFAULT,
+    .ai_family = PF_UNSPEC,
+    .ai_socktype = 0,
+    .ai_protocol = 0,
+    .ai_addrlen = 0,
+    .ai_addr = NULL,
+    .ai_canonname = NULL,
+    .ai_next = NULL
+  };
+
+static void
+gaih_result_reset (struct gaih_result *res)
+{
+  if (res->free_at)
+    free (res->at);
+  free (res->canon);
+  free (res->h_name);
+  memset (res, 0, sizeof (*res));
+}
+
+static int
+gaih_inet_serv (const char *servicename, const struct gaih_typeproto *tp,
+		const struct addrinfo *req, struct gaih_servtuple *st,
+		struct scratch_buffer *tmpbuf)
+{
+  struct servent *s;
+  struct servent ts;
+  int r;
+
+  do
+    {
+      r = __getservbyname_r (servicename, tp->name, &ts,
+			     tmpbuf->data, tmpbuf->length, &s);
+      if (r != 0 || s == NULL)
+	{
+	  if (r == ERANGE)
+	    {
+	      if (!scratch_buffer_grow (tmpbuf))
+		return -EAI_MEMORY;
+	    }
+	  else
+	    return -EAI_SERVICE;
+	}
+    }
+  while (r);
+
+  st->socktype = tp->socktype;
+  st->protocol = ((tp->protoflag & GAI_PROTO_PROTOANY)
+		  ? req->ai_protocol : tp->protocol);
+  st->port = s->s_port;
+  st->set = true;
+
+  return 0;
+}
+
+/* Convert struct hostent to a list of struct gaih_addrtuple objects.  The new
+   addresses are appended to the tuple array in RES.  */
+static bool
+convert_hostent_to_gaih_addrtuple (const struct addrinfo *req, int family,
+				   struct hostent *h, struct gaih_result *res)
+{
+  /* Count the number of addresses in h->h_addr_list.  */
+  size_t count = 0;
+  for (char **p = h->h_addr_list; *p != NULL; ++p)
+    ++count;
+
+  /* Report no data if no addresses are available, or if the incoming
+     address size is larger than what we can store.  */
+  if (count == 0 || h->h_length > sizeof (((struct gaih_addrtuple) {}).addr))
+    return true;
+
+  struct gaih_addrtuple *array = res->at;
+  size_t old = 0;
+
+  while (array != NULL)
+    {
+      old++;
+      array = array->next;
+    }
+
+  array = realloc (res->at, (old + count) * sizeof (*array));
+
+  if (array == NULL)
+    return false;
+
+  res->got_ipv6 = family == AF_INET6;
+  res->at = array;
+  res->free_at = true;
+
+  /* Duplicate h_name because it may get reclaimed when the underlying storage
+     is freed.  */
+  if (res->h_name == NULL)
+    {
+      res->h_name = __strdup (h->h_name);
+      if (res->h_name == NULL)
+	return false;
+    }
+
+  /* Update the next pointers on reallocation.  */
+  for (size_t i = 0; i < old; i++)
+    array[i].next = array + i + 1;
+
+  array += old;
+
+  memset (array, 0, count * sizeof (*array));
+
+  for (size_t i = 0; i < count; ++i)
+    {
+      if (family == AF_INET && req->ai_family == AF_INET6)
+	{
+	  /* Perform address mapping. */
+	  array[i].family = AF_INET6;
+	  memcpy(array[i].addr + 3, h->h_addr_list[i], sizeof (uint32_t));
+	  array[i].addr[2] = htonl (0xffff);
+	}
+      else
+	{
+	  array[i].family = family;
+	  memcpy (array[i].addr, h->h_addr_list[i], h->h_length);
+	}
+      array[i].next = array + i + 1;
+    }
+  array[count - 1].next = NULL;
+
+  return true;
+}
+
+static int
+gethosts (nss_gethostbyname3_r fct, int family, const char *name,
+	  const struct addrinfo *req, struct scratch_buffer *tmpbuf,
+	  struct gaih_result *res, enum nss_status *statusp, int *no_datap)
+{
+  struct hostent th;
+  char *localcanon = NULL;
+  enum nss_status status;
+
+  *no_datap = 0;
+  while (1)
+    {
+      *statusp = status = DL_CALL_FCT (fct, (name, family, &th,
+					     tmpbuf->data, tmpbuf->length,
+					     &errno, &h_errno, NULL,
+					     &localcanon));
+      if (status != NSS_STATUS_TRYAGAIN || h_errno != NETDB_INTERNAL
+	  || errno != ERANGE)
+	break;
+      if (!scratch_buffer_grow (tmpbuf))
+	return -EAI_MEMORY;
+    }
+  if (status == NSS_STATUS_NOTFOUND
+      || status == NSS_STATUS_TRYAGAIN || status == NSS_STATUS_UNAVAIL)
+    {
+      if (h_errno == NETDB_INTERNAL)
+	return -EAI_SYSTEM;
+      if (h_errno == TRY_AGAIN)
+	*no_datap = EAI_AGAIN;
+      else
+	*no_datap = h_errno == NO_DATA;
+    }
+  else if (status == NSS_STATUS_SUCCESS)
+    {
+      if (!convert_hostent_to_gaih_addrtuple (req, family, &th, res))
+	return -EAI_MEMORY;
+
+      if (localcanon != NULL && res->canon == NULL)
+	{
+	  char *canonbuf = __strdup (localcanon);
+	  if (canonbuf == NULL)
+	    return  -EAI_MEMORY;
+	  res->canon = canonbuf;
+	}
+    }
+
+  return 0;
+}
+
+/* This function is called if a canonical name is requested, but if
+   the service function did not provide it.  It tries to obtain the
+   name using getcanonname_r from the same service NIP.  If the name
+   cannot be canonicalized, return a copy of NAME.  Return NULL on
+   memory allocation failure.  The returned string is allocated on the
+   heap; the caller has to free it.  */
+static char *
+getcanonname (nss_action_list nip, const char *hname, const char *name)
+{
+  nss_getcanonname_r *cfct = __nss_lookup_function (nip, "getcanonname_r");
+  char *s = (char *) name;
+  if (cfct != NULL)
+    {
+      char buf[256];
+      if (DL_CALL_FCT (cfct, (hname ?: name, buf, sizeof (buf), &s, &errno,
+			      &h_errno)) != NSS_STATUS_SUCCESS)
+	/* If the canonical name cannot be determined, use the passed
+	   string.  */
+	s = (char *) name;
+    }
+  return __strdup (s);
+}
+
+/* Process looked up canonical name and if necessary, decode to IDNA.  Result
+   is a new string written to CANONP and the earlier string is freed.  */
+
+static int
+process_canonname (const struct addrinfo *req, const char *orig_name,
+		   struct gaih_result *res)
+{
+  char *canon = res->canon;
+
+  if ((req->ai_flags & AI_CANONNAME) != 0)
+    {
+      bool do_idn = req->ai_flags & AI_CANONIDN;
+      if (do_idn)
+	{
+	  char *out;
+	  int rc = __idna_from_dns_encoding (canon ?: orig_name, &out);
+	  if (rc == 0)
+	    {
+	      free (canon);
+	      canon = out;
+	    }
+	  else if (rc == EAI_IDN_ENCODE)
+	    /* Use the punycode name as a fallback.  */
+	    do_idn = false;
+	  else
+	    return -rc;
+	}
+      if (!do_idn && canon == NULL && (canon = __strdup (orig_name)) == NULL)
+	return -EAI_MEMORY;
+    }
+
+  res->canon = canon;
+  return 0;
+}
+
+static int
+get_servtuples (const struct gaih_service *service, const struct addrinfo *req,
+		struct gaih_servtuple *st, struct scratch_buffer *tmpbuf)
+{
+  int i;
+  const struct gaih_typeproto *tp = gaih_inet_typeproto;
+
+  if (req->ai_protocol || req->ai_socktype)
+    {
+      ++tp;
+
+      while (tp->name[0]
+	     && ((req->ai_socktype != 0 && req->ai_socktype != tp->socktype)
+		 || (req->ai_protocol != 0
+		     && !(tp->protoflag & GAI_PROTO_PROTOANY)
+		     && req->ai_protocol != tp->protocol)))
+	++tp;
+
+      if (! tp->name[0])
+	{
+	  if (req->ai_socktype)
+	    return -EAI_SOCKTYPE;
+	  else
+	    return -EAI_SERVICE;
+	}
+    }
+
+  if (service != NULL && (tp->protoflag & GAI_PROTO_NOSERVICE) != 0)
+    return -EAI_SERVICE;
+
+  if (service == NULL || service->num >= 0)
+    {
+      int port = service != NULL ? htons (service->num) : 0;
+
+      if (req->ai_socktype || req->ai_protocol)
+	{
+	  st[0].socktype = tp->socktype;
+	  st[0].protocol = ((tp->protoflag & GAI_PROTO_PROTOANY)
+			  ? req->ai_protocol : tp->protocol);
+	  st[0].port = port;
+	  st[0].set = true;
+
+	  return 0;
+	}
+
+      /* Neither socket type nor protocol is set.  Return all socket types
+	 we know about.  */
+      for (i = 0, ++tp; tp->name[0]; ++tp)
+	if (tp->defaultflag)
+	  {
+	    st[i].socktype = tp->socktype;
+	    st[i].protocol = tp->protocol;
+	    st[i].port = port;
+	    st[i++].set = true;
+	  }
+
+      return 0;
+    }
+
+  if (tp->name[0])
+    return gaih_inet_serv (service->name, tp, req, st, tmpbuf);
+
+  for (i = 0, tp++; tp->name[0]; tp++)
+    {
+      if ((tp->protoflag & GAI_PROTO_NOSERVICE) != 0)
+	continue;
+
+      if (req->ai_socktype != 0
+	  && req->ai_socktype != tp->socktype)
+	continue;
+      if (req->ai_protocol != 0
+	  && !(tp->protoflag & GAI_PROTO_PROTOANY)
+	  && req->ai_protocol != tp->protocol)
+	continue;
+
+      if (gaih_inet_serv (service->name,
+			  tp, req, &st[i], tmpbuf) != 0)
+	continue;
+
+      i++;
+    }
+
+  if (!st[0].set)
+    return -EAI_SERVICE;
+
+  return 0;
+}
+
+#ifdef USE_NSCD
+/* Query addresses from nscd cache, returning a non-zero value on error.
+   RES members have the lookup result; RES->AT is NULL if there were no errors
+   but also no results.  */
+
+static int
+get_nscd_addresses (const char *name, const struct addrinfo *req,
+		    struct gaih_result *res)
+{
+  if (__nss_not_use_nscd_hosts > 0
+      && ++__nss_not_use_nscd_hosts > NSS_NSCD_RETRY)
+    __nss_not_use_nscd_hosts = 0;
+
+  res->at = NULL;
+
+  if (__nss_not_use_nscd_hosts || __nss_database_custom[NSS_DBSIDX_hosts])
+    return 0;
+
+  /* Try to use nscd.  */
+  struct nscd_ai_result *air = NULL;
+  int err = __nscd_getai (name, &air, &h_errno);
+
+  if (__glibc_unlikely (air == NULL))
+    {
+      /* The database contains a negative entry.  */
+      if (err == 0)
+	return -EAI_NONAME;
+      if (__nss_not_use_nscd_hosts == 0)
+	{
+	  if (h_errno == NETDB_INTERNAL && errno == ENOMEM)
+	    return -EAI_MEMORY;
+	  if (h_errno == TRY_AGAIN)
+	    return -EAI_AGAIN;
+	  return -EAI_SYSTEM;
+	}
+      return 0;
+    }
+
+  /* Transform into gaih_addrtuple list.  */
+  int result = 0;
+  char *addrs = air->addrs;
+
+  struct gaih_addrtuple *addrfree = calloc (air->naddrs, sizeof (*addrfree));
+  struct gaih_addrtuple *at = calloc (air->naddrs, sizeof (*at));
+  if (at == NULL)
+    {
+      result = -EAI_MEMORY;
+      goto out;
+    }
+
+  res->free_at = true;
+
+  int count = 0;
+  for (int i = 0; i < air->naddrs; ++i)
+    {
+      socklen_t size = (air->family[i] == AF_INET
+			? INADDRSZ : IN6ADDRSZ);
+
+      if (!((air->family[i] == AF_INET
+	     && req->ai_family == AF_INET6
+	     && (req->ai_flags & AI_V4MAPPED) != 0)
+	    || req->ai_family == AF_UNSPEC
+	    || air->family[i] == req->ai_family))
+	{
+	  /* Skip over non-matching result.  */
+	  addrs += size;
+	  continue;
+	}
+
+      if (air->family[i] == AF_INET && req->ai_family == AF_INET6
+	  && (req->ai_flags & AI_V4MAPPED))
+	{
+	  at[count].family = AF_INET6;
+	  at[count].addr[3] = *(uint32_t *) addrs;
+	  at[count].addr[2] = htonl (0xffff);
+	}
+      else if (req->ai_family == AF_UNSPEC
+	       || air->family[i] == req->ai_family)
+	{
+	  at[count].family = air->family[i];
+	  memcpy (at[count].addr, addrs, size);
+	  if (air->family[i] == AF_INET6)
+	    res->got_ipv6 = true;
+	}
+      at[count].next = at + count + 1;
+      count++;
+      addrs += size;
+    }
+
+  if ((req->ai_flags & AI_CANONNAME) && air->canon != NULL)
+    {
+      char *canonbuf = __strdup (air->canon);
+      if (canonbuf == NULL)
+	{
+	  result = -EAI_MEMORY;
+	  goto out;
+	}
+      res->canon = canonbuf;
+    }
+
+  if (count == 0)
+    {
+      result = -EAI_NONAME;
+      goto out;
+    }
+
+  at[count - 1].next = NULL;
+
+  res->at = at;
+
+out:
+  free (air);
+  if (result != 0)
+    {
+      free (at);
+      res->free_at = false;
+    }
+
+  return result;
+}
+#endif
+
+static int
+get_nss_addresses (const char *name, const struct addrinfo *req,
+		   struct scratch_buffer *tmpbuf, struct gaih_result *res)
+{
+  int no_data = 0;
+  int no_inet6_data = 0;
+  nss_action_list nip;
+  enum nss_status inet6_status = NSS_STATUS_UNAVAIL;
+  enum nss_status status = NSS_STATUS_UNAVAIL;
+  int no_more;
+  struct resolv_context *res_ctx = NULL;
+  bool do_merge = false;
+  int result = 0;
+
+  no_more = !__nss_database_get (nss_database_hosts, &nip);
+
+  /* If we are looking for both IPv4 and IPv6 address we don't
+     want the lookup functions to automatically promote IPv4
+     addresses to IPv6 addresses, so we use the no_inet6
+     function variant.  */
+  res_ctx = __resolv_context_get ();
+  if (res_ctx == NULL)
+    no_more = 1;
+
+  while (!no_more)
+    {
+      /* Always start afresh; continue should discard previous results
+	 and the hosts database does not support merge.  */
+      gaih_result_reset (res);
+
+      if (do_merge)
+	{
+	  __set_h_errno (NETDB_INTERNAL);
+	  __set_errno (EBUSY);
+	  break;
+	}
+
+      no_data = 0;
+      nss_gethostbyname4_r *fct4 = NULL;
+
+      /* gethostbyname4_r sends out parallel A and AAAA queries and
+	 is thus only suitable for PF_UNSPEC.  */
+      if (req->ai_family == PF_UNSPEC)
+	fct4 = __nss_lookup_function (nip, "gethostbyname4_r");
+
+      if (fct4 != NULL)
+	{
+	  while (1)
+	    {
+	      status = DL_CALL_FCT (fct4, (name, &res->at,
+					   tmpbuf->data, tmpbuf->length,
+					   &errno, &h_errno,
+					   NULL));
+	      if (status == NSS_STATUS_SUCCESS)
+		break;
+	      /* gethostbyname4_r may write into AT, so reset it.  */
+	      res->at = NULL;
+	      if (status != NSS_STATUS_TRYAGAIN
+		  || errno != ERANGE || h_errno != NETDB_INTERNAL)
+		{
+		  if (h_errno == TRY_AGAIN)
+		    no_data = EAI_AGAIN;
+		  else
+		    no_data = h_errno == NO_DATA;
+		  break;
+		}
+
+	      if (!scratch_buffer_grow (tmpbuf))
+		{
+		  __resolv_context_put (res_ctx);
+		  result = -EAI_MEMORY;
+		  goto out;
+		}
+	    }
+
+	  if (status == NSS_STATUS_SUCCESS)
+	    {
+	      assert (!no_data);
+	      no_data = 1;
+
+	      if ((req->ai_flags & AI_CANONNAME) != 0 && res->canon == NULL)
+		{
+		  char *canonbuf = __strdup (res->at->name);
+		  if (canonbuf == NULL)
+		    {
+		      __resolv_context_put (res_ctx);
+		      result = -EAI_MEMORY;
+		      goto out;
+		    }
+		  res->canon = canonbuf;
+		}
+
+	      struct gaih_addrtuple **pat = &res->at;
+
+	      while (*pat != NULL)
+		{
+		  if ((*pat)->family == AF_INET
+		      && req->ai_family == AF_INET6
+		      && (req->ai_flags & AI_V4MAPPED) != 0)
+		    {
+		      uint32_t *pataddr = (*pat)->addr;
+		      (*pat)->family = AF_INET6;
+		      pataddr[3] = pataddr[0];
+		      pataddr[2] = htonl (0xffff);
+		      pataddr[1] = 0;
+		      pataddr[0] = 0;
+		      pat = &((*pat)->next);
+		      no_data = 0;
+		    }
+		  else if (req->ai_family == AF_UNSPEC
+			   || (*pat)->family == req->ai_family)
+		    {
+		      pat = &((*pat)->next);
+
+		      no_data = 0;
+		      if (req->ai_family == AF_INET6)
+			res->got_ipv6 = true;
+		    }
+		  else
+		    *pat = ((*pat)->next);
+		}
+	    }
+
+	  no_inet6_data = no_data;
+	}
+      else
+	{
+	  nss_gethostbyname3_r *fct = NULL;
+	  if (req->ai_flags & AI_CANONNAME)
+	    /* No need to use this function if we do not look for
+	       the canonical name.  The function does not exist in
+	       all NSS modules and therefore the lookup would
+	       often fail.  */
+	    fct = __nss_lookup_function (nip, "gethostbyname3_r");
+	  if (fct == NULL)
+	    /* We are cheating here.  The gethostbyname2_r
+	       function does not have the same interface as
+	       gethostbyname3_r but the extra arguments the
+	       latter takes are added at the end.  So the
+	       gethostbyname2_r code will just ignore them.  */
+	    fct = __nss_lookup_function (nip, "gethostbyname2_r");
+
+	  if (fct != NULL)
+	    {
+	      if (req->ai_family == AF_INET6
+		  || req->ai_family == AF_UNSPEC)
+		{
+		  if ((result = gethosts (fct, AF_INET6, name, req, tmpbuf,
+					  res, &status, &no_data)) != 0)
+		    {
+		      __resolv_context_put (res_ctx);
+		      goto out;
+		    }
+		  no_inet6_data = no_data;
+		  inet6_status = status;
+		}
+	      if (req->ai_family == AF_INET
+		  || req->ai_family == AF_UNSPEC
+		  || (req->ai_family == AF_INET6
+		      && (req->ai_flags & AI_V4MAPPED)
+		      /* Avoid generating the mapped addresses if we
+			 know we are not going to need them.  */
+		      && ((req->ai_flags & AI_ALL) || !res->got_ipv6)))
+		{
+		  if ((result = gethosts (fct, AF_INET, name, req, tmpbuf,
+					  res, &status, &no_data)) != 0)
+		    {
+		      __resolv_context_put (res_ctx);
+		      goto out;
+		    }
+
+		  if (req->ai_family == AF_INET)
+		    {
+		      no_inet6_data = no_data;
+		      inet6_status = status;
+		    }
+		}
+
+	      /* If we found one address for AF_INET or AF_INET6,
+		 don't continue the search.  */
+	      if (inet6_status == NSS_STATUS_SUCCESS
+		  || status == NSS_STATUS_SUCCESS)
+		{
+		  if ((req->ai_flags & AI_CANONNAME) != 0
+		      && res->canon == NULL)
+		    {
+		      char *canonbuf = getcanonname (nip, res->h_name, name);
+		      if (canonbuf == NULL)
+			{
+			  __resolv_context_put (res_ctx);
+			  result = -EAI_MEMORY;
+			  goto out;
+			}
+		      res->canon = canonbuf;
+		    }
+		  status = NSS_STATUS_SUCCESS;
+		}
+	      else
+		{
+		  /* We can have different states for AF_INET and
+		     AF_INET6.  Try to find a useful one for both.  */
+		  if (inet6_status == NSS_STATUS_TRYAGAIN)
+		    status = NSS_STATUS_TRYAGAIN;
+		  else if (status == NSS_STATUS_UNAVAIL
+			   && inet6_status != NSS_STATUS_UNAVAIL)
+		    status = inet6_status;
+		}
+	    }
+	  else
+	    {
+	      /* Could not locate any of the lookup functions.
+		 The NSS lookup code does not consistently set
+		 errno, so we need to supply our own error
+		 code here.  The root cause could either be a
+		 resource allocation failure, or a missing
+		 service function in the DSO (so it should not
+		 be listed in /etc/nsswitch.conf).  Assume the
+		 former, and return EBUSY.  */
+	      status = NSS_STATUS_UNAVAIL;
+	      __set_h_errno (NETDB_INTERNAL);
+	      __set_errno (EBUSY);
+	    }
+	}
+
+      if (nss_next_action (nip, status) == NSS_ACTION_RETURN)
+	break;
+
+      /* The hosts database does not support MERGE.  */
+      if (nss_next_action (nip, status) == NSS_ACTION_MERGE)
+	do_merge = true;
+
+      nip++;
+      if (nip->module == NULL)
+	no_more = -1;
+    }
+
+  __resolv_context_put (res_ctx);
+
+  /* If we have a failure which sets errno, report it using
+     EAI_SYSTEM.  */
+  if ((status == NSS_STATUS_TRYAGAIN || status == NSS_STATUS_UNAVAIL)
+      && h_errno == NETDB_INTERNAL)
+    {
+      result = -EAI_SYSTEM;
+      goto out;
+    }
+
+  if (no_data != 0 && no_inet6_data != 0)
+    {
+      /* If both requests timed out report this.  */
+      if (no_data == EAI_AGAIN && no_inet6_data == EAI_AGAIN)
+	result = -EAI_AGAIN;
+      else
+	/* We made requests but they turned out no data.  The name
+	   is known, though.  */
+	result = -EAI_NODATA;
+    }
+
+out:
+  if (result != 0)
+    gaih_result_reset (res);
+  return result;
+}
+
+/* Convert numeric addresses to binary into RES.  On failure, RES->AT is set to
+   NULL and an error code is returned.  If AI_NUMERIC_HOST is not requested and
+   the function cannot determine a result, RES->AT is set to NULL and 0
+   returned.  */
+
+static int
+text_to_binary_address (const char *name, const struct addrinfo *req,
+			struct gaih_result *res)
+{
+  struct gaih_addrtuple *at = res->at;
+  int result = 0;
+
+  assert (at != NULL);
+
+  memset (at->addr, 0, sizeof (at->addr));
+  if (__inet_aton_exact (name, (struct in_addr *) at->addr) != 0)
+    {
+      if (req->ai_family == AF_UNSPEC || req->ai_family == AF_INET)
+	at->family = AF_INET;
+      else if (req->ai_family == AF_INET6 && (req->ai_flags & AI_V4MAPPED))
+	{
+	  at->addr[3] = at->addr[0];
+	  at->addr[2] = htonl (0xffff);
+	  at->addr[1] = 0;
+	  at->addr[0] = 0;
+	  at->family = AF_INET6;
+	}
+      else
+	{
+	  result = -EAI_ADDRFAMILY;
+	  goto out;
+	}
+
+      if (req->ai_flags & AI_CANONNAME)
+	{
+	  char *canonbuf = __strdup (name);
+	  if (canonbuf == NULL)
+	    {
+	      result = -EAI_MEMORY;
+	      goto out;
+	    }
+	  res->canon = canonbuf;
+	}
+      return 0;
+    }
+
+  char *scope_delim = strchr (name, SCOPE_DELIMITER);
+  int e;
+
+  if (scope_delim == NULL)
+    e = inet_pton (AF_INET6, name, at->addr);
+  else
+    e = __inet_pton_length (AF_INET6, name, scope_delim - name, at->addr);
+
+  if (e > 0)
+    {
+      if (req->ai_family == AF_UNSPEC || req->ai_family == AF_INET6)
+	at->family = AF_INET6;
+      else if (req->ai_family == AF_INET
+	       && IN6_IS_ADDR_V4MAPPED (at->addr))
+	{
+	  at->addr[0] = at->addr[3];
+	  at->family = AF_INET;
+	}
+      else
+	{
+	  result = -EAI_ADDRFAMILY;
+	  goto out;
+	}
+
+      if (scope_delim != NULL
+	  && __inet6_scopeid_pton ((struct in6_addr *) at->addr,
+				   scope_delim + 1, &at->scopeid) != 0)
+	{
+	  result = -EAI_NONAME;
+	  goto out;
+	}
+
+      if (req->ai_flags & AI_CANONNAME)
+	{
+	  char *canonbuf = __strdup (name);
+	  if (canonbuf == NULL)
+	    {
+	      result = -EAI_MEMORY;
+	      goto out;
+	    }
+	  res->canon = canonbuf;
+	}
+      return 0;
+    }
+
+  if ((req->ai_flags & AI_NUMERICHOST))
+    result = -EAI_NONAME;
+
+out:
+  res->at = NULL;
+  return result;
+}
+
+/* If possible, call the simple, old functions, which do not support IPv6 scope
+   ids, nor retrieving the canonical name.  */
+
+static int
+try_simple_gethostbyname (const char *name, const struct addrinfo *req,
+			  struct scratch_buffer *tmpbuf,
+			  struct gaih_result *res)
+{
+  res->at = NULL;
+
+  if (req->ai_family != AF_INET || (req->ai_flags & AI_CANONNAME) != 0)
+    return 0;
+
+  int rc;
+  struct hostent th;
+  struct hostent *h;
+
+  while (1)
+    {
+      rc = __gethostbyname2_r (name, AF_INET, &th, tmpbuf->data,
+			       tmpbuf->length, &h, &h_errno);
+      if (rc != ERANGE || h_errno != NETDB_INTERNAL)
+	break;
+      if (!scratch_buffer_grow (tmpbuf))
+	return -EAI_MEMORY;
+    }
+
+  if (rc == 0)
+    {
+      if (h != NULL)
+	{
+	  /* We found data, convert it.  RES->AT from the conversion will
+	     either be an allocated block or NULL, both of which are safe to
+	     pass to free ().  */
+	  if (!convert_hostent_to_gaih_addrtuple (req, AF_INET, h, res))
+	    return -EAI_MEMORY;
+
+	  res->free_at = true;
+	  return 0;
+	}
+      if (h_errno == NO_DATA)
+	return -EAI_NODATA;
+
+      return -EAI_NONAME;
+    }
+
+  if (h_errno == NETDB_INTERNAL)
+    return -EAI_SYSTEM;
+  if (h_errno == TRY_AGAIN)
+    return -EAI_AGAIN;
+
+  /* We made requests but they turned out no data.
+     The name is known, though.  */
+  return -EAI_NODATA;
+}
+
+/* Add local address information into RES.  RES->AT is assumed to have enough
+   space for two tuples and is zeroed out.  */
+
+static void
+get_local_addresses (const struct addrinfo *req, struct gaih_result *res)
+{
+  struct gaih_addrtuple *atr = res->at;
+  if (req->ai_family == AF_UNSPEC)
+    res->at->next = res->at + 1;
+
+  if (req->ai_family == AF_UNSPEC || req->ai_family == AF_INET6)
+    {
+      res->at->family = AF_INET6;
+      if ((req->ai_flags & AI_PASSIVE) == 0)
+	memcpy (res->at->addr, &in6addr_loopback, sizeof (struct in6_addr));
+      atr = res->at->next;
+    }
+
+  if (req->ai_family == AF_UNSPEC || req->ai_family == AF_INET)
+    {
+      atr->family = AF_INET;
+      if ((req->ai_flags & AI_PASSIVE) == 0)
+	atr->addr[0] = htonl (INADDR_LOOPBACK);
+    }
+}
+
+/* Generate results in PAI and its count in NADDRS.  Return 0 on success or an
+   error code on failure.  */
+
+static int
+generate_addrinfo (const struct addrinfo *req, struct gaih_result *res,
+		   const struct gaih_servtuple *st, struct addrinfo **pai,
+		   unsigned int *naddrs)
+{
+  size_t socklen;
+  sa_family_t family;
+
+  /* Buffer is the size of an unformatted IPv6 address in printable format.  */
+  for (struct gaih_addrtuple *at = res->at; at != NULL; at = at->next)
+    {
+      family = at->family;
+      if (family == AF_INET6)
+	{
+	  socklen = sizeof (struct sockaddr_in6);
+
+	  /* If we looked up IPv4 mapped address discard them here if
+	     the caller isn't interested in all address and we have
+	     found at least one IPv6 address.  */
+	  if (res->got_ipv6
+	      && (req->ai_flags & (AI_V4MAPPED|AI_ALL)) == AI_V4MAPPED
+	      && IN6_IS_ADDR_V4MAPPED (at->addr))
+	    continue;
+	}
+      else
+	socklen = sizeof (struct sockaddr_in);
+
+      for (int i = 0; st[i].set; i++)
+	{
+	  struct addrinfo *ai;
+	  ai = *pai = malloc (sizeof (struct addrinfo) + socklen);
+	  if (ai == NULL)
+	    return -EAI_MEMORY;
+
+	  ai->ai_flags = req->ai_flags;
+	  ai->ai_family = family;
+	  ai->ai_socktype = st[i].socktype;
+	  ai->ai_protocol = st[i].protocol;
+	  ai->ai_addrlen = socklen;
+	  ai->ai_addr = (void *) (ai + 1);
+
+	  /* We only add the canonical name once.  */
+	  ai->ai_canonname = res->canon;
+	  res->canon = NULL;
+
+#ifdef _HAVE_SA_LEN
+	  ai->ai_addr->sa_len = socklen;
+#endif /* _HAVE_SA_LEN */
+	  ai->ai_addr->sa_family = family;
+
+	  /* In case of an allocation error the list must be NULL
+	     terminated.  */
+	  ai->ai_next = NULL;
+
+	  if (family == AF_INET6)
+	    {
+	      struct sockaddr_in6 *sin6p = (struct sockaddr_in6 *) ai->ai_addr;
+	      sin6p->sin6_port = st[i].port;
+	      sin6p->sin6_flowinfo = 0;
+	      memcpy (&sin6p->sin6_addr, at->addr, sizeof (struct in6_addr));
+	      sin6p->sin6_scope_id = at->scopeid;
+	    }
+	  else
+	    {
+	      struct sockaddr_in *sinp = (struct sockaddr_in *) ai->ai_addr;
+	      sinp->sin_port = st[i].port;
+	      memcpy (&sinp->sin_addr, at->addr, sizeof (struct in_addr));
+	      memset (sinp->sin_zero, '\0', sizeof (sinp->sin_zero));
+	    }
+
+	  pai = &(ai->ai_next);
+	}
+
+      ++*naddrs;
+    }
+  return 0;
+}
+
+static int
+gaih_inet (const char *name, const struct gaih_service *service,
+	   const struct addrinfo *req, struct addrinfo **pai,
+	   unsigned int *naddrs, struct scratch_buffer *tmpbuf)
+{
+  struct gaih_servtuple st[sizeof (gaih_inet_typeproto)
+			   / sizeof (struct gaih_typeproto)] = {0};
+
+  const char *orig_name = name;
+
+  int rc;
+  if ((rc = get_servtuples (service, req, st, tmpbuf)) != 0)
+    return rc;
+
+  bool malloc_name = false;
+  struct gaih_addrtuple *addrmem = NULL;
+  int result = 0;
+
+  struct gaih_result res = {0};
+  struct gaih_addrtuple local_at[2] = {0};
+
+  res.at = local_at;
+
+  if (__glibc_unlikely (name == NULL))
+    {
+      get_local_addresses (req, &res);
+      goto process_list;
+    }
+
+  if (req->ai_flags & AI_IDN)
+    {
+      char *out;
+      result = __idna_to_dns_encoding (name, &out);
+      if (result != 0)
+	return -result;
+      name = out;
+      malloc_name = true;
+    }
+
+  if ((result = text_to_binary_address (name, req, &res)) != 0)
+    goto free_and_return;
+  else if (res.at != NULL)
+    goto process_list;
+
+  if ((result = try_simple_gethostbyname (name, req, tmpbuf, &res)) != 0)
+    goto free_and_return;
+  else if (res.at != NULL)
+    goto process_list;
+
+#ifdef USE_NSCD
+  if ((result = get_nscd_addresses (name, req, &res)) != 0)
+    goto free_and_return;
+  else if (res.at != NULL)
+    goto process_list;
+#endif
+
+  if ((result = get_nss_addresses (name, req, tmpbuf, &res)) != 0)
+    goto free_and_return;
+  else if (res.at != NULL)
+    goto process_list;
+
+  /* None of the lookups worked, so name not found.  */
+  result = -EAI_NONAME;
+  goto free_and_return;
+
+process_list:
+  /* Set up the canonical name if we need it.  */
+  if ((result = process_canonname (req, orig_name, &res)) != 0)
+    goto free_and_return;
+
+  result = generate_addrinfo (req, &res, st, pai, naddrs);
+
+free_and_return:
+  if (malloc_name)
+    free ((char *) name);
+  free (addrmem);
+  gaih_result_reset (&res);
+
+  return result;
+}
+
+
+struct sort_result
+{
+  struct addrinfo *dest_addr;
+  /* Using sockaddr_storage is for now overkill.  We only support IPv4
+     and IPv6 so far.  If this changes at some point we can adjust the
+     type here.  */
+  struct sockaddr_in6 source_addr;
+  uint8_t source_addr_len;
+  bool got_source_addr;
+  uint8_t source_addr_flags;
+  uint8_t prefixlen;
+  uint32_t index;
+  int32_t native;
+};
+
+struct sort_result_combo
+{
+  struct sort_result *results;
+  int nresults;
+};
+
+
+#if __BYTE_ORDER == __BIG_ENDIAN
+# define htonl_c(n) n
+#else
+# define htonl_c(n) __bswap_constant_32 (n)
+#endif
+
+static const struct scopeentry
+{
+  union
+  {
+    char addr[4];
+    uint32_t addr32;
+  };
+  uint32_t netmask;
+  int32_t scope;
+} default_scopes[] =
+  {
+    /* Link-local addresses: scope 2.  */
+    { { { 169, 254, 0, 0 } }, htonl_c (0xffff0000), 2 },
+    { { { 127, 0, 0, 0 } }, htonl_c (0xff000000), 2 },
+    /* Default: scope 14.  */
+    { { { 0, 0, 0, 0 } }, htonl_c (0x00000000), 14 }
+  };
+
+/* The label table.  */
+static const struct scopeentry *scopes;
+
+
+static int
+get_scope (const struct sockaddr_in6 *in6)
+{
+  int scope;
+  if (in6->sin6_family == PF_INET6)
+    {
+      if (! IN6_IS_ADDR_MULTICAST (&in6->sin6_addr))
+	{
+	  if (IN6_IS_ADDR_LINKLOCAL (&in6->sin6_addr)
+	      /* RFC 4291 2.5.3 says that the loopback address is to be
+		 treated like a link-local address.  */
+	      || IN6_IS_ADDR_LOOPBACK (&in6->sin6_addr))
+	    scope = 2;
+	  else if (IN6_IS_ADDR_SITELOCAL (&in6->sin6_addr))
+	    scope = 5;
+	  else
+	    /* XXX Is this the correct default behavior?  */
+	    scope = 14;
+	}
+      else
+	scope = in6->sin6_addr.s6_addr[1] & 0xf;
+    }
+  else if (in6->sin6_family == PF_INET)
+    {
+      const struct sockaddr_in *in = (const struct sockaddr_in *) in6;
+
+      size_t cnt = 0;
+      while (1)
+	{
+	  if ((in->sin_addr.s_addr & scopes[cnt].netmask)
+	      == scopes[cnt].addr32)
+	    return scopes[cnt].scope;
+
+	  ++cnt;
+	}
+      /* NOTREACHED */
+    }
+  else
+    /* XXX What is a good default?  */
+    scope = 15;
+
+  return scope;
+}
+
+
+struct prefixentry
+{
+  struct in6_addr prefix;
+  unsigned int bits;
+  int val;
+};
+
+
+/* The label table.  */
+static const struct prefixentry *labels;
+
+/* Default labels.  */
+static const struct prefixentry default_labels[] =
+  {
+    /* See RFC 3484 for the details.  */
+    { { .__in6_u
+	= { .__u6_addr8 = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+			    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01 } }
+      }, 128, 0 },
+    { { .__in6_u
+	= { .__u6_addr8 = { 0x20, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+			    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 } }
+      }, 16, 2 },
+    { { .__in6_u
+	= { .__u6_addr8 = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+			    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 } }
+      }, 96, 3 },
+    { { .__in6_u
+	= { .__u6_addr8 = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+			    0x00, 0x00, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00 } }
+      }, 96, 4 },
+    /* The next two entries differ from RFC 3484.  We need to treat
+       IPv6 site-local addresses special because they are never NATed,
+       unlike site-locale IPv4 addresses.  If this would not happen, on
+       machines which have only IPv4 and IPv6 site-local addresses, the
+       sorting would prefer the IPv6 site-local addresses, causing
+       unnecessary delays when trying to connect to a global IPv6 address
+       through a site-local IPv6 address.  */
+    { { .__in6_u
+	= { .__u6_addr8 = { 0xfe, 0xc0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+			    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 } }
+      }, 10, 5 },
+    { { .__in6_u
+	= { .__u6_addr8 = { 0xfc, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+			    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 } }
+      }, 7, 6 },
+    /* Additional rule for Teredo tunnels.  */
+    { { .__in6_u
+	= { .__u6_addr8 = { 0x20, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+			    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 } }
+      }, 32, 7 },
+    { { .__in6_u
+	= { .__u6_addr8 = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+			    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 } }
+      }, 0, 1 }
+  };
+
+
+/* The precedence table.  */
+static const struct prefixentry *precedence;
+
+/* The default precedences.  */
+static const struct prefixentry default_precedence[] =
+  {
+    /* See RFC 3484 for the details.  */
+    { { .__in6_u
+	= { .__u6_addr8 = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+			    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01 } }
+      }, 128, 50 },
+    { { .__in6_u
+	= { .__u6_addr8 = { 0x20, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+			    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 } }
+      }, 16, 30 },
+    { { .__in6_u
+	= { .__u6_addr8 = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+			  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 } }
+      }, 96, 20 },
+    { { .__in6_u
+	= { .__u6_addr8 = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+			    0x00, 0x00, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00 } }
+      }, 96, 10 },
+    { { .__in6_u
+	= { .__u6_addr8 = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+			    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 } }
+      }, 0, 40 }
+  };
+
+
+static int
+match_prefix (const struct sockaddr_in6 *in6,
+	      const struct prefixentry *list, int default_val)
+{
+  int idx;
+  struct sockaddr_in6 in6_mem;
+
+  if (in6->sin6_family == PF_INET)
+    {
+      const struct sockaddr_in *in = (const struct sockaddr_in *) in6;
+
+      /* Construct a V4-to-6 mapped address.  */
+      in6_mem.sin6_family = PF_INET6;
+      in6_mem.sin6_port = in->sin_port;
+      in6_mem.sin6_flowinfo = 0;
+      memset (&in6_mem.sin6_addr, '\0', sizeof (in6_mem.sin6_addr));
+      in6_mem.sin6_addr.s6_addr16[5] = 0xffff;
+      in6_mem.sin6_addr.s6_addr32[3] = in->sin_addr.s_addr;
+      in6_mem.sin6_scope_id = 0;
+
+      in6 = &in6_mem;
+    }
+  else if (in6->sin6_family != PF_INET6)
+    return default_val;
+
+  for (idx = 0; ; ++idx)
+    {
+      unsigned int bits = list[idx].bits;
+      const uint8_t *mask = list[idx].prefix.s6_addr;
+      const uint8_t *val = in6->sin6_addr.s6_addr;
+
+      while (bits >= 8)
+	{
+	  if (*mask != *val)
+	    break;
+
+	  ++mask;
+	  ++val;
+	  bits -= 8;
+	}
+
+      if (bits < 8)
+	{
+	  if ((*mask & (0xff00 >> bits)) == (*val & (0xff00 >> bits)))
+	    /* Match!  */
+	    break;
+	}
+    }
+
+  return list[idx].val;
+}
+
+
+static int
+get_label (const struct sockaddr_in6 *in6)
+{
+  /* XXX What is a good default value?  */
+  return match_prefix (in6, labels, INT_MAX);
+}
+
+
+static int
+get_precedence (const struct sockaddr_in6 *in6)
+{
+  /* XXX What is a good default value?  */
+  return match_prefix (in6, precedence, 0);
+}
+
+
+/* Find last bit set in a word.  */
+static int
+fls (uint32_t a)
+{
+  uint32_t mask;
+  int n;
+  for (n = 0, mask = 1 << 31; n < 32; mask >>= 1, ++n)
+    if ((a & mask) != 0)
+      break;
+  return n;
+}
+
+
+static int
+rfc3484_sort (const void *p1, const void *p2, void *arg)
+{
+  const size_t idx1 = *(const size_t *) p1;
+  const size_t idx2 = *(const size_t *) p2;
+  struct sort_result_combo *src = (struct sort_result_combo *) arg;
+  struct sort_result *a1 = &src->results[idx1];
+  struct sort_result *a2 = &src->results[idx2];
+
+  /* Rule 1: Avoid unusable destinations.
+     We have the got_source_addr flag set if the destination is reachable.  */
+  if (a1->got_source_addr && ! a2->got_source_addr)
+    return -1;
+  if (! a1->got_source_addr && a2->got_source_addr)
+    return 1;
+
+
+  /* Rule 2: Prefer matching scope.  Only interesting if both
+     destination addresses are IPv6.  */
+  int a1_dst_scope
+    = get_scope ((struct sockaddr_in6 *) a1->dest_addr->ai_addr);
+
+  int a2_dst_scope
+    = get_scope ((struct sockaddr_in6 *) a2->dest_addr->ai_addr);
+
+  if (a1->got_source_addr)
+    {
+      int a1_src_scope = get_scope (&a1->source_addr);
+      int a2_src_scope = get_scope (&a2->source_addr);
+
+      if (a1_dst_scope == a1_src_scope && a2_dst_scope != a2_src_scope)
+	return -1;
+      if (a1_dst_scope != a1_src_scope && a2_dst_scope == a2_src_scope)
+	return 1;
+    }
+
+
+  /* Rule 3: Avoid deprecated addresses.  */
+  if (a1->got_source_addr)
+    {
+      if (!(a1->source_addr_flags & in6ai_deprecated)
+	  && (a2->source_addr_flags & in6ai_deprecated))
+	return -1;
+      if ((a1->source_addr_flags & in6ai_deprecated)
+	  && !(a2->source_addr_flags & in6ai_deprecated))
+	return 1;
+    }
+
+  /* Rule 4: Prefer home addresses.  */
+  if (a1->got_source_addr)
+    {
+      if (!(a1->source_addr_flags & in6ai_homeaddress)
+	  && (a2->source_addr_flags & in6ai_homeaddress))
+	return 1;
+      if ((a1->source_addr_flags & in6ai_homeaddress)
+	  && !(a2->source_addr_flags & in6ai_homeaddress))
+	return -1;
+    }
+
+  /* Rule 5: Prefer matching label.  */
+  if (a1->got_source_addr)
+    {
+      int a1_dst_label
+	= get_label ((struct sockaddr_in6 *) a1->dest_addr->ai_addr);
+      int a1_src_label = get_label (&a1->source_addr);
+
+      int a2_dst_label
+	= get_label ((struct sockaddr_in6 *) a2->dest_addr->ai_addr);
+      int a2_src_label = get_label (&a2->source_addr);
+
+      if (a1_dst_label == a1_src_label && a2_dst_label != a2_src_label)
+	return -1;
+      if (a1_dst_label != a1_src_label && a2_dst_label == a2_src_label)
+	return 1;
+    }
+
+
+  /* Rule 6: Prefer higher precedence.  */
+  int a1_prec
+    = get_precedence ((struct sockaddr_in6 *) a1->dest_addr->ai_addr);
+  int a2_prec
+    = get_precedence ((struct sockaddr_in6 *) a2->dest_addr->ai_addr);
+
+  if (a1_prec > a2_prec)
+    return -1;
+  if (a1_prec < a2_prec)
+    return 1;
+
+
+  /* Rule 7: Prefer native transport.  */
+  if (a1->got_source_addr)
+    {
+      /* The same interface index means the same interface which means
+	 there is no difference in transport.  This should catch many
+	 (most?) cases.  */
+      if (a1->index != a2->index)
+	{
+	  int a1_native = a1->native;
+	  int a2_native = a2->native;
+
+	  if (a1_native == -1 || a2_native == -1)
+	    {
+	      uint32_t a1_index;
+	      if (a1_native == -1)
+		{
+		  /* If we do not have the information use 'native' as
+		     the default.  */
+		  a1_native = 0;
+		  a1_index = a1->index;
+		}
+	      else
+		a1_index = 0xffffffffu;
+
+	      uint32_t a2_index;
+	      if (a2_native == -1)
+		{
+		  /* If we do not have the information use 'native' as
+		     the default.  */
+		  a2_native = 0;
+		  a2_index = a2->index;
+		}
+	      else
+		a2_index = 0xffffffffu;
+
+	      __check_native (a1_index, &a1_native, a2_index, &a2_native);
+
+	      /* Fill in the results in all the records.  */
+	      for (int i = 0; i < src->nresults; ++i)
+		if (a1_index != -1 && src->results[i].index == a1_index)
+		  {
+		    assert (src->results[i].native == -1
+			    || src->results[i].native == a1_native);
+		    src->results[i].native = a1_native;
+		  }
+		else if (a2_index != -1 && src->results[i].index == a2_index)
+		  {
+		    assert (src->results[i].native == -1
+			    || src->results[i].native == a2_native);
+		    src->results[i].native = a2_native;
+		  }
+	    }
+
+	  if (a1_native && !a2_native)
+	    return -1;
+	  if (!a1_native && a2_native)
+	    return 1;
+	}
+    }
+
+
+  /* Rule 8: Prefer smaller scope.  */
+  if (a1_dst_scope < a2_dst_scope)
+    return -1;
+  if (a1_dst_scope > a2_dst_scope)
+    return 1;
+
+
+  /* Rule 9: Use longest matching prefix.  */
+  if (a1->got_source_addr
+      && a1->dest_addr->ai_family == a2->dest_addr->ai_family)
+    {
+      int bit1 = 0;
+      int bit2 = 0;
+
+      if (a1->dest_addr->ai_family == PF_INET)
+	{
+	  assert (a1->source_addr.sin6_family == PF_INET);
+	  assert (a2->source_addr.sin6_family == PF_INET);
+
+	  /* Outside of subnets, as defined by the network masks,
+	     common address prefixes for IPv4 addresses make no sense.
+	     So, define a non-zero value only if source and
+	     destination address are on the same subnet.  */
+	  struct sockaddr_in *in1_dst
+	    = (struct sockaddr_in *) a1->dest_addr->ai_addr;
+	  in_addr_t in1_dst_addr = ntohl (in1_dst->sin_addr.s_addr);
+	  struct sockaddr_in *in1_src
+	    = (struct sockaddr_in *) &a1->source_addr;
+	  in_addr_t in1_src_addr = ntohl (in1_src->sin_addr.s_addr);
+	  in_addr_t netmask1 = 0xffffffffu << (32 - a1->prefixlen);
+
+	  if ((in1_src_addr & netmask1) == (in1_dst_addr & netmask1))
+	    bit1 = fls (in1_dst_addr ^ in1_src_addr);
+
+	  struct sockaddr_in *in2_dst
+	    = (struct sockaddr_in *) a2->dest_addr->ai_addr;
+	  in_addr_t in2_dst_addr = ntohl (in2_dst->sin_addr.s_addr);
+	  struct sockaddr_in *in2_src
+	    = (struct sockaddr_in *) &a2->source_addr;
+	  in_addr_t in2_src_addr = ntohl (in2_src->sin_addr.s_addr);
+	  in_addr_t netmask2 = 0xffffffffu << (32 - a2->prefixlen);
+
+	  if ((in2_src_addr & netmask2) == (in2_dst_addr & netmask2))
+	    bit2 = fls (in2_dst_addr ^ in2_src_addr);
+	}
+      else if (a1->dest_addr->ai_family == PF_INET6)
+	{
+	  assert (a1->source_addr.sin6_family == PF_INET6);
+	  assert (a2->source_addr.sin6_family == PF_INET6);
+
+	  struct sockaddr_in6 *in1_dst;
+	  struct sockaddr_in6 *in1_src;
+	  struct sockaddr_in6 *in2_dst;
+	  struct sockaddr_in6 *in2_src;
+
+	  in1_dst = (struct sockaddr_in6 *) a1->dest_addr->ai_addr;
+	  in1_src = (struct sockaddr_in6 *) &a1->source_addr;
+	  in2_dst = (struct sockaddr_in6 *) a2->dest_addr->ai_addr;
+	  in2_src = (struct sockaddr_in6 *) &a2->source_addr;
+
+	  int i;
+	  for (i = 0; i < 4; ++i)
+	    if (in1_dst->sin6_addr.s6_addr32[i]
+		!= in1_src->sin6_addr.s6_addr32[i]
+		|| (in2_dst->sin6_addr.s6_addr32[i]
+		    != in2_src->sin6_addr.s6_addr32[i]))
+	      break;
+
+	  if (i < 4)
+	    {
+	      bit1 = fls (ntohl (in1_dst->sin6_addr.s6_addr32[i]
+				 ^ in1_src->sin6_addr.s6_addr32[i]));
+	      bit2 = fls (ntohl (in2_dst->sin6_addr.s6_addr32[i]
+				 ^ in2_src->sin6_addr.s6_addr32[i]));
+	    }
+	}
+
+      if (bit1 > bit2)
+	return -1;
+      if (bit1 < bit2)
+	return 1;
+    }
+
+
+  /* Rule 10: Otherwise, leave the order unchanged.  To ensure this
+     compare with the value indicating the order in which the entries
+     have been received from the services.  NB: no two entries can have
+     the same order so the test will never return zero.  */
+  return idx1 < idx2 ? -1 : 1;
+}
+
+
+static int
+in6aicmp (const void *p1, const void *p2)
+{
+  struct in6addrinfo *a1 = (struct in6addrinfo *) p1;
+  struct in6addrinfo *a2 = (struct in6addrinfo *) p2;
+
+  return memcmp (a1->addr, a2->addr, sizeof (a1->addr));
+}
+
+
+/* Name of the config file for RFC 3484 sorting (for now).  */
+#define GAICONF_FNAME "/etc/gai.conf"
+
+
+/* Non-zero if we are supposed to reload the config file automatically
+   whenever it changed.  */
+static int gaiconf_reload_flag;
+
+/* Non-zero if gaiconf_reload_flag was ever set to true.  */
+static int gaiconf_reload_flag_ever_set;
+
+/* Last modification time.  */
+#ifdef _STATBUF_ST_NSEC
+
+static struct __timespec64 gaiconf_mtime;
+
+static inline void
+save_gaiconf_mtime (const struct __stat64_t64 *st)
+{
+  gaiconf_mtime = (struct __timespec64) { st->st_mtim.tv_sec,
+					  st->st_mtim.tv_nsec };
+}
+
+static inline bool
+check_gaiconf_mtime (const struct __stat64_t64 *st)
+{
+  return (st->st_mtim.tv_sec == gaiconf_mtime.tv_sec
+          && st->st_mtim.tv_nsec == gaiconf_mtime.tv_nsec);
+}
+
+#else
+
+static time_t gaiconf_mtime;
+
+static inline void
+save_gaiconf_mtime (const struct __stat64_t64 *st)
+{
+  gaiconf_mtime = st->st_mtime;
+}
+
+static inline bool
+check_gaiconf_mtime (const struct __stat64_t64 *st)
+{
+  return st->st_mtime == gaiconf_mtime;
+}
+
+#endif
+
+
+void
+__libc_getaddrinfo_freemem (void)
+{
+  if (labels != default_labels)
+    {
+      const struct prefixentry *old = labels;
+      labels = default_labels;
+      free ((void *) old);
+    }
+
+  if (precedence != default_precedence)
+    {
+      const struct prefixentry *old = precedence;
+      precedence = default_precedence;
+      free ((void *) old);
+    }
+
+  if (scopes != default_scopes)
+    {
+      const struct scopeentry *old = scopes;
+      scopes = default_scopes;
+      free ((void *) old);
+    }
+}
+
+
+struct prefixlist
+{
+  struct prefixentry entry;
+  struct prefixlist *next;
+};
+
+
+struct scopelist
+{
+  struct scopeentry entry;
+  struct scopelist *next;
+};
+
+
+static void
+free_prefixlist (struct prefixlist *list)
+{
+  while (list != NULL)
+    {
+      struct prefixlist *oldp = list;
+      list = list->next;
+      free (oldp);
+    }
+}
+
+
+static void
+free_scopelist (struct scopelist *list)
+{
+  while (list != NULL)
+    {
+      struct scopelist *oldp = list;
+      list = list->next;
+      free (oldp);
+    }
+}
+
+
+static int
+prefixcmp (const void *p1, const void *p2)
+{
+  const struct prefixentry *e1 = (const struct prefixentry *) p1;
+  const struct prefixentry *e2 = (const struct prefixentry *) p2;
+
+  if (e1->bits < e2->bits)
+    return 1;
+  if (e1->bits == e2->bits)
+    return 0;
+  return -1;
+}
+
+
+static int
+scopecmp (const void *p1, const void *p2)
+{
+  const struct scopeentry *e1 = (const struct scopeentry *) p1;
+  const struct scopeentry *e2 = (const struct scopeentry *) p2;
+
+  if (e1->netmask > e2->netmask)
+    return -1;
+  if (e1->netmask == e2->netmask)
+    return 0;
+  return 1;
+}
+
+static bool
+add_prefixlist (struct prefixlist **listp, size_t *lenp, bool *nullbitsp,
+		char *val1, char *val2, char **pos)
+{
+  struct in6_addr prefix;
+  unsigned long int bits;
+  unsigned long int val;
+  char *endp;
+
+  bits = 128;
+  __set_errno (0);
+  char *cp = strchr (val1, '/');
+  if (cp != NULL)
+    *cp++ = '\0';
+  *pos = cp;
+  if (inet_pton (AF_INET6, val1, &prefix)
+      && (cp == NULL
+	  || (bits = strtoul (cp, &endp, 10)) != ULONG_MAX
+	  || errno != ERANGE)
+      && *endp == '\0'
+      && bits <= 128
+      && ((val = strtoul (val2, &endp, 10)) != ULONG_MAX
+	  || errno != ERANGE)
+      && *endp == '\0'
+      && val <= INT_MAX)
+    {
+      struct prefixlist *newp = malloc (sizeof (*newp));
+      if (newp == NULL)
+	return false;
+
+      memcpy (&newp->entry.prefix, &prefix, sizeof (prefix));
+      newp->entry.bits = bits;
+      newp->entry.val = val;
+      newp->next = *listp;
+      *listp = newp;
+      ++*lenp;
+      *nullbitsp |= bits == 0;
+    }
+  return true;
+}
+
+static bool
+add_scopelist (struct scopelist **listp, size_t *lenp, bool *nullbitsp,
+	       const struct in6_addr *prefixp, unsigned long int bits,
+	       unsigned long int val)
+{
+  struct scopelist *newp = malloc (sizeof (*newp));
+  if (newp == NULL)
+    return false;
+
+  newp->entry.netmask = htonl (bits != 96 ? (0xffffffff << (128 - bits)) : 0);
+  newp->entry.addr32 = (prefixp->s6_addr32[3] & newp->entry.netmask);
+  newp->entry.scope = val;
+  newp->next = *listp;
+  *listp = newp;
+  ++*lenp;
+  *nullbitsp |= bits == 96;
+
+  return true;
+}
+
+static void
+gaiconf_init (void)
+{
+  struct prefixlist *labellist = NULL;
+  size_t nlabellist = 0;
+  bool labellist_nullbits = false;
+  struct prefixlist *precedencelist = NULL;
+  size_t nprecedencelist = 0;
+  bool precedencelist_nullbits = false;
+  struct scopelist *scopelist =  NULL;
+  size_t nscopelist = 0;
+  bool scopelist_nullbits = false;
+
+  FILE *fp = fopen (GAICONF_FNAME, "rce");
+  if (fp == NULL)
+    goto no_file;
+
+  struct __stat64_t64 st;
+  if (__fstat64_time64 (fileno (fp), &st) != 0)
+    {
+      fclose (fp);
+      goto no_file;
+    }
+
+  char *line = NULL;
+  size_t linelen = 0;
+
+  __fsetlocking (fp, FSETLOCKING_BYCALLER);
+
+  while (!feof_unlocked (fp))
+    {
+      ssize_t n = __getline (&line, &linelen, fp);
+      if (n <= 0)
+	break;
+
+      /* Handle comments.  No escaping possible so this is easy.  */
+      char *cp = strchr (line, '#');
+      if (cp != NULL)
+	*cp = '\0';
+
+      cp = line;
+      while (isspace (*cp))
+	++cp;
+
+      char *cmd = cp;
+      while (*cp != '\0' && !isspace (*cp))
+	++cp;
+      size_t cmdlen = cp - cmd;
+
+      if (*cp != '\0')
+	*cp++ = '\0';
+      while (isspace (*cp))
+	++cp;
+
+      char *val1 = cp;
+      while (*cp != '\0' && !isspace (*cp))
+	++cp;
+      size_t val1len = cp - cmd;
+
+      /* We always need at least two values.  */
+      if (val1len == 0)
+	continue;
+
+      if (*cp != '\0')
+	*cp++ = '\0';
+      while (isspace (*cp))
+	++cp;
+
+      char *val2 = cp;
+      while (*cp != '\0' && !isspace (*cp))
+	++cp;
+
+      /*  Ignore the rest of the line.  */
+      *cp = '\0';
+
+      switch (cmdlen)
+	{
+	case 5:
+	  if (strcmp (cmd, "label") == 0)
+	    {
+	      if (!add_prefixlist (&labellist, &nlabellist,
+				   &labellist_nullbits, val1, val2, &cp))
+		{
+		  free (line);
+		  fclose (fp);
+		  goto no_file;
+		}
+	    }
+	  break;
+
+	case 6:
+	  if (strcmp (cmd, "reload") == 0)
+	    {
+	      gaiconf_reload_flag = strcmp (val1, "yes") == 0;
+	      if (gaiconf_reload_flag)
+		gaiconf_reload_flag_ever_set = 1;
+	    }
+	  break;
+
+	case 7:
+	  if (strcmp (cmd, "scopev4") == 0)
+	    {
+	      struct in6_addr prefix;
+	      unsigned long int bits;
+	      unsigned long int val;
+	      char *endp;
+
+	      bits = 32;
+	      __set_errno (0);
+	      cp = strchr (val1, '/');
+	      if (cp != NULL)
+		*cp++ = '\0';
+	      if (inet_pton (AF_INET6, val1, &prefix))
+		{
+		  bits = 128;
+		  if (IN6_IS_ADDR_V4MAPPED (&prefix)
+		      && (cp == NULL
+			  || (bits = strtoul (cp, &endp, 10)) != ULONG_MAX
+			  || errno != ERANGE)
+		      && *endp == '\0'
+		      && bits >= 96
+		      && bits <= 128
+		      && ((val = strtoul (val2, &endp, 10)) != ULONG_MAX
+			  || errno != ERANGE)
+		      && *endp == '\0'
+		      && val <= INT_MAX)
+		    {
+		      if (!add_scopelist (&scopelist, &nscopelist,
+					  &scopelist_nullbits, &prefix,
+					  bits, val))
+			{
+			  free (line);
+			  fclose (fp);
+			  goto no_file;
+			}
+		    }
+		}
+	      else if (inet_pton (AF_INET, val1, &prefix.s6_addr32[3])
+		       && (cp == NULL
+			   || (bits = strtoul (cp, &endp, 10)) != ULONG_MAX
+			   || errno != ERANGE)
+		       && *endp == '\0'
+		       && bits <= 32
+		       && ((val = strtoul (val2, &endp, 10)) != ULONG_MAX
+			   || errno != ERANGE)
+		       && *endp == '\0'
+		       && val <= INT_MAX)
+		{
+		  if (!add_scopelist (&scopelist, &nscopelist,
+				      &scopelist_nullbits, &prefix,
+				      bits + 96, val))
+		    {
+		      free (line);
+		      fclose (fp);
+		      goto no_file;
+		    }
+		}
+	    }
+	  break;
+
+	case 10:
+	  if (strcmp (cmd, "precedence") == 0)
+	    {
+	      if (!add_prefixlist (&precedencelist, &nprecedencelist,
+				   &precedencelist_nullbits, val1, val2,
+				   &cp))
+		{
+		  free (line);
+		  fclose (fp);
+		  goto no_file;
+		}
+	    }
+	  break;
+	}
+    }
+
+  free (line);
+
+  fclose (fp);
+
+  /* Create the array for the labels.  */
+  struct prefixentry *new_labels;
+  if (nlabellist > 0)
+    {
+      if (!labellist_nullbits)
+	++nlabellist;
+      new_labels = malloc (nlabellist * sizeof (*new_labels));
+      if (new_labels == NULL)
+	goto no_file;
+
+      int i = nlabellist;
+      if (!labellist_nullbits)
+	{
+	  --i;
+	  memset (&new_labels[i].prefix, '\0', sizeof (struct in6_addr));
+	  new_labels[i].bits = 0;
+	  new_labels[i].val = 1;
+	}
+
+      struct prefixlist *l = labellist;
+      while (i-- > 0)
+	{
+	  new_labels[i] = l->entry;
+	  l = l->next;
+	}
+      free_prefixlist (labellist);
+      labellist = NULL;
+
+      /* Sort the entries so that the most specific ones are at
+	 the beginning.  */
+      qsort (new_labels, nlabellist, sizeof (*new_labels), prefixcmp);
+    }
+  else
+    new_labels = (struct prefixentry *) default_labels;
+
+  struct prefixentry *new_precedence;
+  if (nprecedencelist > 0)
+    {
+      if (!precedencelist_nullbits)
+	++nprecedencelist;
+      new_precedence = malloc (nprecedencelist * sizeof (*new_precedence));
+      if (new_precedence == NULL)
+	{
+	  if (new_labels != default_labels)
+	    free (new_labels);
+	  goto no_file;
+	}
+
+      int i = nprecedencelist;
+      if (!precedencelist_nullbits)
+	{
+	  --i;
+	  memset (&new_precedence[i].prefix, '\0',
+		  sizeof (struct in6_addr));
+	  new_precedence[i].bits = 0;
+	  new_precedence[i].val = 40;
+	}
+
+      struct prefixlist *l = precedencelist;
+      while (i-- > 0)
+	{
+	  new_precedence[i] = l->entry;
+	  l = l->next;
+	}
+      free_prefixlist (precedencelist);
+      precedencelist = NULL;
+
+      /* Sort the entries so that the most specific ones are at
+	 the beginning.  */
+      qsort (new_precedence, nprecedencelist, sizeof (*new_precedence),
+	     prefixcmp);
+    }
+  else
+    new_precedence = (struct prefixentry *) default_precedence;
+
+  struct scopeentry *new_scopes;
+  if (nscopelist > 0)
+    {
+      if (!scopelist_nullbits)
+	++nscopelist;
+      new_scopes = malloc (nscopelist * sizeof (*new_scopes));
+      if (new_scopes == NULL)
+	{
+	  if (new_labels != default_labels)
+	    free (new_labels);
+	  if (new_precedence != default_precedence)
+	    free (new_precedence);
+	  goto no_file;
+	}
+
+      int i = nscopelist;
+      if (!scopelist_nullbits)
+	{
+	  --i;
+	  new_scopes[i].addr32 = 0;
+	  new_scopes[i].netmask = 0;
+	  new_scopes[i].scope = 14;
+	}
+
+      struct scopelist *l = scopelist;
+      while (i-- > 0)
+	{
+	  new_scopes[i] = l->entry;
+	  l = l->next;
+	}
+      free_scopelist (scopelist);
+
+      /* Sort the entries so that the most specific ones are at
+	 the beginning.  */
+      qsort (new_scopes, nscopelist, sizeof (*new_scopes),
+	     scopecmp);
+    }
+  else
+    new_scopes = (struct scopeentry *) default_scopes;
+
+  /* Now we are ready to replace the values.  */
+  const struct prefixentry *old = labels;
+  labels = new_labels;
+  if (old != default_labels)
+    free ((void *) old);
+
+  old = precedence;
+  precedence = new_precedence;
+  if (old != default_precedence)
+    free ((void *) old);
+
+  const struct scopeentry *oldscope = scopes;
+  scopes = new_scopes;
+  if (oldscope != default_scopes)
+    free ((void *) oldscope);
+
+  save_gaiconf_mtime (&st);
+  return;
+
+no_file:
+  free_prefixlist (labellist);
+  free_prefixlist (precedencelist);
+  free_scopelist (scopelist);
+
+  /* If we previously read the file but it is gone now, free the old data and
+     use the builtin one.  Leave the reload flag alone.  */
+  __libc_getaddrinfo_freemem ();
+}
+
+
+static void
+gaiconf_reload (void)
+{
+  struct __stat64_t64 st;
+  if (__stat64_time64 (GAICONF_FNAME, &st) != 0
+      || !check_gaiconf_mtime (&st))
+    gaiconf_init ();
+}
+
+static bool
+try_connect (int *fdp, int *afp, struct sockaddr_in6 *source_addrp,
+	     const struct sockaddr *addr, socklen_t addrlen, int family)
+{
+  int fd = *fdp;
+  int af = *afp;
+  socklen_t sl = sizeof (*source_addrp);
+
+  while (true)
+    {
+      if (fd != -1 && __connect (fd, addr, addrlen) == 0
+	  && __getsockname (fd, (struct sockaddr *) source_addrp, &sl) == 0)
+	return true;
+
+      if (errno == EAFNOSUPPORT && af == AF_INET6 && family == AF_INET)
+	{
+	  /* This could mean IPv6 sockets are IPv6-only.  */
+	  if (fd != -1)
+	    __close_nocancel_nostatus (fd);
+	  *afp = af = AF_INET;
+	  *fdp = fd = __socket (AF_INET, SOCK_DGRAM | SOCK_CLOEXEC,
+				IPPROTO_IP);
+	  continue;
+	}
+
+      return false;
+    }
+
+  __builtin_unreachable ();
+}
+
+int
+getaddrinfo (const char *name, const char *service,
+	     const struct addrinfo *hints, struct addrinfo **pai)
+{
+  int i = 0, last_i = 0;
+  int nresults = 0;
+  struct addrinfo *p = NULL;
+  struct gaih_service gaih_service, *pservice;
+  struct addrinfo local_hints;
+
+  if (name != NULL && name[0] == '*' && name[1] == 0)
+    name = NULL;
+
+  if (service != NULL && service[0] == '*' && service[1] == 0)
+    service = NULL;
+
+  if (name == NULL && service == NULL)
+    return EAI_NONAME;
+
+  if (hints == NULL)
+    hints = &default_hints;
+
+  if (hints->ai_flags
+      & ~(AI_PASSIVE|AI_CANONNAME|AI_NUMERICHOST|AI_ADDRCONFIG|AI_V4MAPPED
+	  |AI_IDN|AI_CANONIDN|DEPRECATED_AI_IDN
+	  |AI_NUMERICSERV|AI_ALL))
+    return EAI_BADFLAGS;
+
+  if ((hints->ai_flags & AI_CANONNAME) && name == NULL)
+    return EAI_BADFLAGS;
+
+  if (hints->ai_family != AF_UNSPEC && hints->ai_family != AF_INET
+      && hints->ai_family != AF_INET6)
+    return EAI_FAMILY;
+
+  struct in6addrinfo *in6ai = NULL;
+  size_t in6ailen = 0;
+  bool seen_ipv4 = false;
+  bool seen_ipv6 = false;
+  bool check_pf_called = false;
+
+  if (hints->ai_flags & AI_ADDRCONFIG)
+    {
+      /* We might need information about what interfaces are available.
+	 Also determine whether we have IPv4 or IPv6 interfaces or both.  We
+	 cannot cache the results since new interfaces could be added at
+	 any time.  */
+      __check_pf (&seen_ipv4, &seen_ipv6, &in6ai, &in6ailen);
+      check_pf_called = true;
+
+      /* Now make a decision on what we return, if anything.  */
+      if (hints->ai_family == PF_UNSPEC && (seen_ipv4 || seen_ipv6))
+	{
+	  /* If we haven't seen both IPv4 and IPv6 interfaces we can
+	     narrow down the search.  */
+	  if (seen_ipv4 != seen_ipv6)
+	    {
+	      local_hints = *hints;
+	      local_hints.ai_family = seen_ipv4 ? PF_INET : PF_INET6;
+	      hints = &local_hints;
+	    }
+	}
+      else if ((hints->ai_family == PF_INET && ! seen_ipv4)
+	       || (hints->ai_family == PF_INET6 && ! seen_ipv6))
+	{
+	  /* We cannot possibly return a valid answer.  */
+	  __free_in6ai (in6ai);
+	  return EAI_NONAME;
+	}
+    }
+
+  if (service && service[0])
+    {
+      char *c;
+      gaih_service.name = service;
+      gaih_service.num = strtoul (gaih_service.name, &c, 10);
+      if (*c != '\0')
+	{
+	  if (hints->ai_flags & AI_NUMERICSERV)
+	    {
+	      __free_in6ai (in6ai);
+	      return EAI_NONAME;
+	    }
+
+	  gaih_service.num = -1;
+	}
+
+      pservice = &gaih_service;
+    }
+  else
+    pservice = NULL;
+
+  struct addrinfo **end = &p;
+  unsigned int naddrs = 0;
+  struct scratch_buffer tmpbuf;
+
+  scratch_buffer_init (&tmpbuf);
+  last_i = gaih_inet (name, pservice, hints, end, &naddrs, &tmpbuf);
+  scratch_buffer_free (&tmpbuf);
+
+  if (last_i != 0)
+    {
+      freeaddrinfo (p);
+      __free_in6ai (in6ai);
+
+      return -last_i;
+    }
+
+  while (*end)
+    {
+      end = &((*end)->ai_next);
+      ++nresults;
+    }
+
+  if (naddrs > 1)
+    {
+      /* Read the config file.  */
+      __libc_once_define (static, once);
+      __typeof (once) old_once = once;
+      __libc_once (once, gaiconf_init);
+      /* Sort results according to RFC 3484.  */
+      struct sort_result *results;
+      size_t *order;
+      struct addrinfo *q;
+      struct addrinfo *last = NULL;
+      char *canonname = NULL;
+      struct scratch_buffer buf;
+      scratch_buffer_init (&buf);
+
+      if (!scratch_buffer_set_array_size (&buf, nresults,
+					  sizeof (*results) + sizeof (size_t)))
+	{
+	  __free_in6ai (in6ai);
+	  return EAI_MEMORY;
+	}
+      results = buf.data;
+
+      order = (size_t *) (results + nresults);
+
+      /* Now we definitely need the interface information.  */
+      if (! check_pf_called)
+	__check_pf (&seen_ipv4, &seen_ipv6, &in6ai, &in6ailen);
+
+      /* If we have information about deprecated and temporary addresses
+	 sort the array now.  */
+      if (in6ai != NULL)
+	qsort (in6ai, in6ailen, sizeof (*in6ai), in6aicmp);
+
+      int fd = -1;
+      int af = AF_UNSPEC;
+
+      for (i = 0, q = p; q != NULL; ++i, last = q, q = q->ai_next)
+	{
+	  results[i].dest_addr = q;
+	  results[i].native = -1;
+	  order[i] = i;
+
+	  /* If we just looked up the address for a different
+	     protocol, reuse the result.  */
+	  if (last != NULL && last->ai_addrlen == q->ai_addrlen
+	      && memcmp (last->ai_addr, q->ai_addr, q->ai_addrlen) == 0)
+	    {
+	      memcpy (&results[i].source_addr, &results[i - 1].source_addr,
+		      results[i - 1].source_addr_len);
+	      results[i].source_addr_len = results[i - 1].source_addr_len;
+	      results[i].got_source_addr = results[i - 1].got_source_addr;
+	      results[i].source_addr_flags = results[i - 1].source_addr_flags;
+	      results[i].prefixlen = results[i - 1].prefixlen;
+	      results[i].index = results[i - 1].index;
+	    }
+	  else
+	    {
+	      results[i].got_source_addr = false;
+	      results[i].source_addr_flags = 0;
+	      results[i].prefixlen = 0;
+	      results[i].index = 0xffffffffu;
+
+	      /* We overwrite the type with SOCK_DGRAM since we do not
+		 want connect() to connect to the other side.  If we
+		 cannot determine the source address remember this
+		 fact.  */
+	      if (fd == -1 || (af == AF_INET && q->ai_family == AF_INET6))
+		{
+		  if (fd != -1)
+		    __close_nocancel_nostatus (fd);
+		  af = q->ai_family;
+		  fd = __socket (af, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_IP);
+		}
+	      else
+		{
+		  /* Reset the connection.  */
+		  struct sockaddr sa = { .sa_family = AF_UNSPEC };
+		  __connect (fd, &sa, sizeof (sa));
+		}
+
+	      if (try_connect (&fd, &af, &results[i].source_addr, q->ai_addr,
+			       q->ai_addrlen, q->ai_family))
+		{
+		  results[i].source_addr_len = sizeof (results[i].source_addr);
+		  results[i].got_source_addr = true;
+
+		  if (in6ai != NULL)
+		    {
+		      /* See whether the source address is on the list of
+			 deprecated or temporary addresses.  */
+		      struct in6addrinfo tmp;
+
+		      if (q->ai_family == AF_INET && af == AF_INET)
+			{
+			  struct sockaddr_in *sinp
+			    = (struct sockaddr_in *) &results[i].source_addr;
+			  tmp.addr[0] = 0;
+			  tmp.addr[1] = 0;
+			  tmp.addr[2] = htonl (0xffff);
+			  /* Special case for lo interface, the source address
+			     being possibly different than the interface
+			     address. */
+			  if ((ntohl(sinp->sin_addr.s_addr) & 0xff000000)
+			      == 0x7f000000)
+			    tmp.addr[3] = htonl(0x7f000001);
+			  else
+			    tmp.addr[3] = sinp->sin_addr.s_addr;
+			}
+		      else
+			{
+			  struct sockaddr_in6 *sin6p
+			    = (struct sockaddr_in6 *) &results[i].source_addr;
+			  memcpy (tmp.addr, &sin6p->sin6_addr, IN6ADDRSZ);
+			}
+
+		      struct in6addrinfo *found
+			= bsearch (&tmp, in6ai, in6ailen, sizeof (*in6ai),
+				   in6aicmp);
+		      if (found != NULL)
+			{
+			  results[i].source_addr_flags = found->flags;
+			  results[i].prefixlen = found->prefixlen;
+			  results[i].index = found->index;
+			}
+		    }
+
+		  if (q->ai_family == AF_INET && af == AF_INET6)
+		    {
+		      /* We have to convert the address.  The socket is
+			 IPv6 and the request is for IPv4.  */
+		      struct sockaddr_in6 *sin6
+			= (struct sockaddr_in6 *) &results[i].source_addr;
+		      struct sockaddr_in *sin
+			= (struct sockaddr_in *) &results[i].source_addr;
+		      assert (IN6_IS_ADDR_V4MAPPED (sin6->sin6_addr.s6_addr32));
+		      sin->sin_family = AF_INET;
+		      /* We do not have to initialize sin_port since this
+			 fields has the same position and size in the IPv6
+			 structure.  */
+		      assert (offsetof (struct sockaddr_in, sin_port)
+			      == offsetof (struct sockaddr_in6, sin6_port));
+		      assert (sizeof (sin->sin_port)
+			      == sizeof (sin6->sin6_port));
+		      memcpy (&sin->sin_addr,
+			      &sin6->sin6_addr.s6_addr32[3], INADDRSZ);
+		      results[i].source_addr_len = sizeof (struct sockaddr_in);
+		    }
+		}
+	      else
+		/* Just make sure that if we have to process the same
+		   address again we do not copy any memory.  */
+		results[i].source_addr_len = 0;
+	    }
+
+	  /* Remember the canonical name.  */
+	  if (q->ai_canonname != NULL)
+	    {
+	      assert (canonname == NULL);
+	      canonname = q->ai_canonname;
+	      q->ai_canonname = NULL;
+	    }
+	}
+
+      if (fd != -1)
+	__close_nocancel_nostatus (fd);
+
+      /* We got all the source addresses we can get, now sort using
+	 the information.  */
+      struct sort_result_combo src
+	= { .results = results, .nresults = nresults };
+      if (__glibc_unlikely (gaiconf_reload_flag_ever_set))
+	{
+	  __libc_lock_define_initialized (static, lock);
+
+	  __libc_lock_lock (lock);
+	  if (__libc_once_get (old_once) && gaiconf_reload_flag)
+	    gaiconf_reload ();
+	  __qsort_r (order, nresults, sizeof (order[0]), rfc3484_sort, &src);
+	  __libc_lock_unlock (lock);
+	}
+      else
+	__qsort_r (order, nresults, sizeof (order[0]), rfc3484_sort, &src);
+
+      /* Queue the results up as they come out of sorting.  */
+      q = p = results[order[0]].dest_addr;
+      for (i = 1; i < nresults; ++i)
+	q = q->ai_next = results[order[i]].dest_addr;
+      q->ai_next = NULL;
+
+      /* Fill in the canonical name into the new first entry.  */
+      p->ai_canonname = canonname;
+
+      scratch_buffer_free (&buf);
+    }
+
+  __free_in6ai (in6ai);
+
+  if (p)
+    {
+      *pai = p;
+      return 0;
+    }
+
+  return last_i ? -last_i : EAI_NONAME;
+}
+libc_hidden_def (getaddrinfo)
+
+nss_interface_function (getaddrinfo)
+
+void
+freeaddrinfo (struct addrinfo *ai)
+{
+  struct addrinfo *p;
+
+  while (ai != NULL)
+    {
+      p = ai;
+      ai = ai->ai_next;
+      free (p->ai_canonname);
+      free (p);
+    }
+}
+libc_hidden_def (freeaddrinfo)