[thirdparty/glibc.git] / nscd / nscd_gethst_r.c

/* Copyright (C) 1998-2014 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Ulrich Drepper <drepper@cygnus.com>, 1998.

   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
   <http://www.gnu.org/licenses/>.  */

#include <errno.h>
#include <resolv.h>
#include <stdio.h>
#include <string.h>
#include <stdint.h>
#include <arpa/nameser.h>
#include <not-cancel.h>

#include "nscd-client.h"
#include "nscd_proto.h"

int __nss_not_use_nscd_hosts;

static int nscd_gethst_r (const char *key, size_t keylen, request_type type,
			  struct hostent *resultbuf, char *buffer,
			  size_t buflen, struct hostent **result,
			  int *h_errnop) internal_function;


int
__nscd_gethostbyname_r (const char *name, struct hostent *resultbuf,
			char *buffer, size_t buflen, struct hostent **result,
			int *h_errnop)
{
  request_type reqtype;

  reqtype = (_res.options & RES_USE_INET6) ? GETHOSTBYNAMEv6 : GETHOSTBYNAME;

  return nscd_gethst_r (name, strlen (name) + 1, reqtype, resultbuf,
			buffer, buflen, result, h_errnop);
}


int
__nscd_gethostbyname2_r (const char *name, int af, struct hostent *resultbuf,
			 char *buffer, size_t buflen, struct hostent **result,
			 int *h_errnop)
{
  request_type reqtype;

  reqtype = af == AF_INET6 ? GETHOSTBYNAMEv6 : GETHOSTBYNAME;

  return nscd_gethst_r (name, strlen (name) + 1, reqtype, resultbuf,
			buffer, buflen, result, h_errnop);
}


int
__nscd_gethostbyaddr_r (const void *addr, socklen_t len, int type,
			struct hostent *resultbuf, char *buffer, size_t buflen,
			struct hostent **result, int *h_errnop)
{
  request_type reqtype;

  if (!((len == INADDRSZ && type == AF_INET)
	|| (len == IN6ADDRSZ && type == AF_INET6)))
    /* LEN and TYPE do not match.  */
    return -1;

  reqtype = type == AF_INET6 ? GETHOSTBYADDRv6 : GETHOSTBYADDR;

  return nscd_gethst_r (addr, len, reqtype, resultbuf, buffer, buflen, result,
			h_errnop);
}


libc_locked_map_ptr (, __hst_map_handle) attribute_hidden;
/* Note that we only free the structure if necessary.  The memory
   mapping is not removed since it is not visible to the malloc
   handling.  */
libc_freeres_fn (hst_map_free)
{
  if (__hst_map_handle.mapped != NO_MAPPING)
    {
      void *p = __hst_map_handle.mapped;
      __hst_map_handle.mapped = NO_MAPPING;
      free (p);
    }
}


uint32_t
__nscd_get_nl_timestamp (void)
{
  uint32_t retval;
  if (__nss_not_use_nscd_hosts != 0)
    return 0;

  /* __nscd_get_mapping can change hst_map_handle.mapped to NO_MAPPING.
   However, __nscd_get_mapping assumes the prior value was not NO_MAPPING.
   Thus we have to acquire the lock to prevent this thread from changing
   hst_map_handle.mapped to NO_MAPPING while another thread is inside
    __nscd_get_mapping.  */
  if (!__nscd_acquire_maplock (&__hst_map_handle))
    return 0;

  struct mapped_database *map = __hst_map_handle.mapped;

  if (map == NULL
      || (map != NO_MAPPING
	  && map->head->nscd_certainly_running == 0
	  && map->head->timestamp + MAPPING_TIMEOUT < time (NULL)))
    map = __nscd_get_mapping (GETFDHST, "hosts", &__hst_map_handle.mapped);

  if (map == NO_MAPPING)
    retval = 0;
  else
    retval = map->head->extra_data[NSCD_HST_IDX_CONF_TIMESTAMP];

  /* Release the lock.  */
  __hst_map_handle.lock = 0;

  return retval;
}


int __nss_have_localdomain attribute_hidden;

static int
internal_function
nscd_gethst_r (const char *key, size_t keylen, request_type type,
	       struct hostent *resultbuf, char *buffer, size_t buflen,
	       struct hostent **result, int *h_errnop)
{
  if (__builtin_expect (__nss_have_localdomain >= 0, 0))
    {
      if (__nss_have_localdomain == 0)
	__nss_have_localdomain = getenv ("LOCALDOMAIN") != NULL ? 1 : -1;
      if (__nss_have_localdomain > 0)
	{
	  __nss_not_use_nscd_hosts = 1;
	  return -1;
	}
    }

  int gc_cycle;
  int nretries = 0;

  /* If the mapping is available, try to search there instead of
     communicating with the nscd.  */
  struct mapped_database *mapped;
  mapped = __nscd_get_map_ref (GETFDHST, "hosts", &__hst_map_handle,
			       &gc_cycle);

 retry:;
  const char *h_name = NULL;
  const uint32_t *aliases_len = NULL;
  const char *addr_list = NULL;
  size_t addr_list_len = 0;
  int retval = -1;
  const char *recend = (const char *) ~UINTMAX_C (0);
  int sock = -1;
  hst_response_header hst_resp;
  if (mapped != NO_MAPPING)
    {
      /* No const qualifier, as it can change during garbage collection.  */
      struct datahead *found = __nscd_cache_search (type, key, keylen, mapped,
						    sizeof hst_resp);
      if (found != NULL)
	{
	  h_name = (char *) (&found->data[0].hstdata + 1);
	  hst_resp = found->data[0].hstdata;
	  aliases_len = (uint32_t *) (h_name + hst_resp.h_name_len);
	  addr_list = ((char *) aliases_len
		       + hst_resp.h_aliases_cnt * sizeof (uint32_t));
	  addr_list_len = hst_resp.h_addr_list_cnt * INADDRSZ;
	  recend = (const char *) found->data + found->recsize;
	  /* Now check if we can trust hst_resp fields.  If GC is
	     in progress, it can contain anything.  */
	  if (mapped->head->gc_cycle != gc_cycle)
	    {
	      retval = -2;
	      goto out;
	    }

#ifndef _STRING_ARCH_unaligned
	  /* The aliases_len array in the mapped database might very
	     well be unaligned.  We will access it word-wise so on
	     platforms which do not tolerate unaligned accesses we
	     need to make an aligned copy.  */
	  if (((uintptr_t) aliases_len & (__alignof__ (*aliases_len) - 1))
	      != 0)
	    {
	      uint32_t *tmp = alloca (hst_resp.h_aliases_cnt
				      * sizeof (uint32_t));
	      aliases_len = memcpy (tmp, aliases_len,
				    hst_resp.h_aliases_cnt
				    * sizeof (uint32_t));
	    }
#endif
	  if (type != GETHOSTBYADDR && type != GETHOSTBYNAME)
	    {
	      if (hst_resp.h_length == INADDRSZ)
		addr_list += addr_list_len;
	      addr_list_len = hst_resp.h_addr_list_cnt * IN6ADDRSZ;
	    }
	  if (__builtin_expect ((const char *) addr_list + addr_list_len
				> recend, 0))
	    goto out;
	}
    }

  if (h_name == NULL)
    {
      sock = __nscd_open_socket (key, keylen, type, &hst_resp,
				 sizeof (hst_resp));
      if (sock == -1)
	{
	  __nss_not_use_nscd_hosts = 1;
	  goto out;
	}
    }

  /* No value found so far.  */
  *result = NULL;

  if (__builtin_expect (hst_resp.found == -1, 0))
    {
      /* The daemon does not cache this database.  */
      __nss_not_use_nscd_hosts = 1;
      goto out_close;
    }

  if (hst_resp.found == 1)
    {
      char *cp = buffer;
      uintptr_t align1;
      uintptr_t align2;
      size_t total_len;
      ssize_t cnt;
      char *ignore;
      int n;

      /* A first check whether the buffer is sufficiently large is possible.  */
      /* Now allocate the buffer the array for the group members.  We must
	 align the pointer and the base of the h_addr_list pointers.  */
      align1 = ((__alignof__ (char *) - (cp - ((char *) 0)))
		& (__alignof__ (char *) - 1));
      align2 = ((__alignof__ (char *) - ((cp + align1 + hst_resp.h_name_len)
					 - ((char *) 0)))
		& (__alignof__ (char *) - 1));
      if (buflen < (align1 + hst_resp.h_name_len + align2
		    + ((hst_resp.h_aliases_cnt + hst_resp.h_addr_list_cnt
			+ 2)
		       * sizeof (char *))
		    + hst_resp.h_addr_list_cnt * (type == AF_INET
						  ? INADDRSZ : IN6ADDRSZ)))
	{
	no_room:
	  *h_errnop = NETDB_INTERNAL;
	  __set_errno (ERANGE);
	  retval = ERANGE;
	  goto out_close;
	}
      cp += align1;

      /* Prepare the result as far as we can.  */
      resultbuf->h_aliases = (char **) cp;
      cp += (hst_resp.h_aliases_cnt + 1) * sizeof (char *);
      resultbuf->h_addr_list = (char **) cp;
      cp += (hst_resp.h_addr_list_cnt + 1) * sizeof (char *);

      resultbuf->h_name = cp;
      cp += hst_resp.h_name_len + align2;

      if (type == GETHOSTBYADDR || type == GETHOSTBYNAME)
	{
	  resultbuf->h_addrtype = AF_INET;
	  resultbuf->h_length = INADDRSZ;
	}
      else
	{
	  resultbuf->h_addrtype = AF_INET6;
	  resultbuf->h_length = IN6ADDRSZ;
	}
      for (cnt = 0; cnt < hst_resp.h_addr_list_cnt; ++cnt)
	{
	  resultbuf->h_addr_list[cnt] = cp;
	  cp += resultbuf->h_length;
	}
      resultbuf->h_addr_list[cnt] = NULL;

      if (h_name == NULL)
	{
	  struct iovec vec[4];

	  vec[0].iov_base = resultbuf->h_name;
	  vec[0].iov_len = hst_resp.h_name_len;
	  total_len = hst_resp.h_name_len;
	  n = 1;

	  if (hst_resp.h_aliases_cnt > 0)
	    {
	      aliases_len = alloca (hst_resp.h_aliases_cnt
				    * sizeof (uint32_t));
	      vec[n].iov_base = (void *) aliases_len;
	      vec[n].iov_len = hst_resp.h_aliases_cnt * sizeof (uint32_t);

	      total_len += hst_resp.h_aliases_cnt * sizeof (uint32_t);
	      ++n;
	    }

	  if (type == GETHOSTBYADDR || type == GETHOSTBYNAME)
	    {
	      vec[n].iov_base = resultbuf->h_addr_list[0];
	      vec[n].iov_len = hst_resp.h_addr_list_cnt * INADDRSZ;

	      total_len += hst_resp.h_addr_list_cnt * INADDRSZ;

	      ++n;
	    }
	  else
	    {
	      if (hst_resp.h_length == INADDRSZ)
		{
		  ignore = alloca (hst_resp.h_addr_list_cnt * INADDRSZ);
		  vec[n].iov_base = ignore;
		  vec[n].iov_len = hst_resp.h_addr_list_cnt * INADDRSZ;

		  total_len += hst_resp.h_addr_list_cnt * INADDRSZ;

		  ++n;
		}

	      vec[n].iov_base = resultbuf->h_addr_list[0];
	      vec[n].iov_len = hst_resp.h_addr_list_cnt * IN6ADDRSZ;

	      total_len += hst_resp.h_addr_list_cnt * IN6ADDRSZ;

	      ++n;
	    }

	  if ((size_t) __readvall (sock, vec, n) != total_len)
	    goto out_close;
	}
      else
	{
	  memcpy (resultbuf->h_name, h_name, hst_resp.h_name_len);
	  memcpy (resultbuf->h_addr_list[0], addr_list, addr_list_len);
	}

      /*  Now we also can read the aliases.  */
      total_len = 0;
      for (cnt = 0; cnt < hst_resp.h_aliases_cnt; ++cnt)
	{
	  resultbuf->h_aliases[cnt] = cp;
	  cp += aliases_len[cnt];
	  total_len += aliases_len[cnt];
	}
      resultbuf->h_aliases[cnt] = NULL;

      if (__builtin_expect ((const char *) addr_list + addr_list_len
			    + total_len > recend, 0))
	{
	  /* aliases_len array might contain garbage during nscd GC cycle,
	     retry rather than fail in that case.  */
	  if (addr_list != NULL && mapped->head->gc_cycle != gc_cycle)
	    retval = -2;
	  goto out_close;
	}
      /* See whether this would exceed the buffer capacity.  */
      if (__builtin_expect (cp > buffer + buflen, 0))
	{
	  /* aliases_len array might contain garbage during nscd GC cycle,
	     retry rather than fail in that case.  */
	  if (addr_list != NULL && mapped->head->gc_cycle != gc_cycle)
	    {
	      retval = -2;
	      goto out_close;
	    }
	  goto no_room;
	}

      /* And finally read the aliases.  */
      if (addr_list == NULL)
	{
	  if (total_len == 0
	      || ((size_t) __readall (sock, resultbuf->h_aliases[0], total_len)
		  == total_len))
	    {
	      retval = 0;
	      *result = resultbuf;
	    }
	}
      else
	{
	  memcpy (resultbuf->h_aliases[0],
		  (const char *) addr_list + addr_list_len, total_len);

	  /* Try to detect corrupt databases.  */
	  if (resultbuf->h_name[hst_resp.h_name_len - 1] != '\0'
	      || ({for (cnt = 0; cnt < hst_resp.h_aliases_cnt; ++cnt)
		     if (resultbuf->h_aliases[cnt][aliases_len[cnt] - 1]
			 != '\0')
		       break;
		   cnt < hst_resp.h_aliases_cnt; }))
	    {
	      /* We cannot use the database.  */
	      if (mapped->head->gc_cycle != gc_cycle)
		retval = -2;
	      goto out_close;
	    }

	  retval = 0;
	  *result = resultbuf;
	}
    }
  else
    {
      /* Store the error number.  */
      *h_errnop = hst_resp.error;

      /* Set errno to 0 to indicate no error, just no found record.  */
      __set_errno (0);
      /* Even though we have not found anything, the result is zero.  */
      retval = 0;
    }

 out_close:
  if (sock != -1)
    close_not_cancel_no_status (sock);
 out:
  if (__nscd_drop_map_ref (mapped, &gc_cycle) != 0)
    {
      /* When we come here this means there has been a GC cycle while we
	 were looking for the data.  This means the data might have been
	 inconsistent.  Retry if possible.  */
      if ((gc_cycle & 1) != 0 || ++nretries == 5 || retval == -1)
	{
	  /* nscd is just running gc now.  Disable using the mapping.  */
	  if (atomic_decrement_val (&mapped->counter) == 0)
	    __nscd_unmap (mapped);
	  mapped = NO_MAPPING;
	}

      if (retval != -1)
	goto retry;
    }

  return retval;
}
Commit	Line	Data
d4697bc9	1	/* Copyright (C) 1998-2014 Free Software Foundation, Inc.
67479a70 UD	2	This file is part of the GNU C Library.
	3	Contributed by Ulrich Drepper <drepper@cygnus.com>, 1998.
	4
	5	The GNU C Library is free software; you can redistribute it and/or
41bdb6e2 AJ	6	modify it under the terms of the GNU Lesser General Public
	7	License as published by the Free Software Foundation; either
	8	version 2.1 of the License, or (at your option) any later version.
67479a70 UD	9
	10	The GNU C Library is distributed in the hope that it will be useful,
	11	but WITHOUT ANY WARRANTY; without even the implied warranty of
	12	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
41bdb6e2	13	Lesser General Public License for more details.
67479a70	14
41bdb6e2	15	You should have received a copy of the GNU Lesser General Public
59ba27a6 PE	16	License along with the GNU C Library; if not, see
59ba27a6 PE	17	<http://www.gnu.org/licenses/>. */
67479a70 UD	18
67479a70 UD	19	#include <errno.h>
67479a70 UD	20	#include <resolv.h>
67479a70 UD	21	#include <stdio.h>
67479a70	22	#include <string.h>
e054f494	23	#include <stdint.h>
67479a70	24	#include <arpa/nameser.h>
40c38b6c	25	#include <not-cancel.h>
67479a70	26
3f804c95	27	#include "nscd-client.h"
67479a70 UD	28	#include "nscd_proto.h"
	29
	30	int __nss_not_use_nscd_hosts;
	31
	32	static int nscd_gethst_r (const char *key, size_t keylen, request_type type,
	33	struct hostent resultbuf, char buffer,
261eada2 UD	34	size_t buflen, struct hostent **result,
261eada2 UD	35	int *h_errnop) internal_function;
67479a70 UD	36
	37
	38	int
	39	__nscd_gethostbyname_r (const char name, struct hostent resultbuf,
261eada2 UD	40	char buffer, size_t buflen, struct hostent *result,
261eada2 UD	41	int *h_errnop)
67479a70 UD	42	{
	43	request_type reqtype;
	44
	45	reqtype = (_res.options & RES_USE_INET6) ? GETHOSTBYNAMEv6 : GETHOSTBYNAME;
	46
	47	return nscd_gethst_r (name, strlen (name) + 1, reqtype, resultbuf,
261eada2	48	buffer, buflen, result, h_errnop);
67479a70 UD	49	}
	50
	51
	52	int
	53	__nscd_gethostbyname2_r (const char name, int af, struct hostent resultbuf,
261eada2 UD	54	char buffer, size_t buflen, struct hostent *result,
261eada2 UD	55	int *h_errnop)
67479a70 UD	56	{
	57	request_type reqtype;
	58
	59	reqtype = af == AF_INET6 ? GETHOSTBYNAMEv6 : GETHOSTBYNAME;
	60
	61	return nscd_gethst_r (name, strlen (name) + 1, reqtype, resultbuf,
261eada2	62	buffer, buflen, result, h_errnop);
67479a70 UD	63	}
	64
	65
	66	int
9d4d69b8	67	__nscd_gethostbyaddr_r (const void *addr, socklen_t len, int type,
67479a70	68	struct hostent resultbuf, char buffer, size_t buflen,
261eada2	69	struct hostent *result, int h_errnop)
67479a70 UD	70	{
	71	request_type reqtype;
	72
	73	if (!((len == INADDRSZ && type == AF_INET)
	74	\|\| (len == IN6ADDRSZ && type == AF_INET6)))
	75	/* LEN and TYPE do not match. */
1670698f	76	return -1;
67479a70 UD	77
	78	reqtype = type == AF_INET6 ? GETHOSTBYADDRv6 : GETHOSTBYADDR;
	79
261eada2	80	return nscd_gethst_r (addr, len, reqtype, resultbuf, buffer, buflen, result,
67479a70 UD	81	h_errnop);
	82	}
	83
	84
6f8a7dff	85	libc_locked_map_ptr (, __hst_map_handle) attribute_hidden;
c207f23b UD	86	/* Note that we only free the structure if necessary. The memory
	87	mapping is not removed since it is not visible to the malloc
	88	handling. */
ed2ced8a	89	libc_freeres_fn (hst_map_free)
67479a70	90	{
ed2ced8a UD	91	if (__hst_map_handle.mapped != NO_MAPPING)
	92	{
	93	void *p = __hst_map_handle.mapped;
	94	__hst_map_handle.mapped = NO_MAPPING;
	95	free (p);
	96	}
67479a70 UD	97	}
	98
	99
3a2c0242 UD	100	uint32_t
	101	__nscd_get_nl_timestamp (void)
	102	{
509072a0	103	uint32_t retval;
3a2c0242 UD	104	if (__nss_not_use_nscd_hosts != 0)
	105	return 0;
	106
509072a0 AJ	107	/* __nscd_get_mapping can change hst_map_handle.mapped to NO_MAPPING.
	108	However, __nscd_get_mapping assumes the prior value was not NO_MAPPING.
	109	Thus we have to acquire the lock to prevent this thread from changing
	110	hst_map_handle.mapped to NO_MAPPING while another thread is inside
	111	__nscd_get_mapping. */
	112	if (!__nscd_acquire_maplock (&__hst_map_handle))
	113	return 0;
	114
3a2c0242 UD	115	struct mapped_database *map = __hst_map_handle.mapped;
	116
	117	if (map == NULL
	118	\|\| (map != NO_MAPPING
	119	&& map->head->nscd_certainly_running == 0
	120	&& map->head->timestamp + MAPPING_TIMEOUT < time (NULL)))
	121	map = __nscd_get_mapping (GETFDHST, "hosts", &__hst_map_handle.mapped);
	122
	123	if (map == NO_MAPPING)
509072a0 AJ	124	retval = 0;
	125	else
	126	retval = map->head->extra_data[NSCD_HST_IDX_CONF_TIMESTAMP];
	127
	128	/* Release the lock. */
	129	__hst_map_handle.lock = 0;
3a2c0242	130
509072a0	131	return retval;
3a2c0242 UD	132	}
	133
	134
50e481ce UD	135	int __nss_have_localdomain attribute_hidden;
50e481ce UD	136
67479a70	137	static int
813f4f4d	138	internal_function
67479a70 UD	139	nscd_gethst_r (const char *key, size_t keylen, request_type type,
67479a70 UD	140	struct hostent resultbuf, char buffer, size_t buflen,
261eada2	141	struct hostent *result, int h_errnop)
67479a70	142	{
50e481ce UD	143	if (__builtin_expect (__nss_have_localdomain >= 0, 0))
	144	{
	145	if (__nss_have_localdomain == 0)
	146	__nss_have_localdomain = getenv ("LOCALDOMAIN") != NULL ? 1 : -1;
	147	if (__nss_have_localdomain > 0)
	148	{
	149	__nss_not_use_nscd_hosts = 1;
	150	return -1;
	151	}
	152	}
	153
0891f970 UD	154	int gc_cycle;
	155	int nretries = 0;
	156
	157	/* If the mapping is available, try to search there instead of
	158	communicating with the nscd. */
	159	struct mapped_database *mapped;
ed2ced8a UD	160	mapped = __nscd_get_map_ref (GETFDHST, "hosts", &__hst_map_handle,
ed2ced8a UD	161	&gc_cycle);
0891f970 UD	162
0891f970 UD	163	retry:;
c207f23b UD	164	const char *h_name = NULL;
	165	const uint32_t *aliases_len = NULL;
	166	const char *addr_list = NULL;
	167	size_t addr_list_len = 0;
	168	int retval = -1;
c207f23b UD	169	const char recend = (const char ) ~UINTMAX_C (0);
c207f23b UD	170	int sock = -1;
1a77d37f	171	hst_response_header hst_resp;
af38d7ce	172	if (mapped != NO_MAPPING)
67479a70	173	{
1a77d37f	174	/* No const qualifier, as it can change during garbage collection. */
cfe1fc10 JJ	175	struct datahead *found = __nscd_cache_search (type, key, keylen, mapped,
cfe1fc10 JJ	176	sizeof hst_resp);
c207f23b UD	177	if (found != NULL)
c207f23b UD	178	{
1a77d37f JJ	179	h_name = (char *) (&found->data[0].hstdata + 1);
	180	hst_resp = found->data[0].hstdata;
	181	aliases_len = (uint32_t *) (h_name + hst_resp.h_name_len);
c207f23b	182	addr_list = ((char *) aliases_len
1a77d37f JJ	183	+ hst_resp.h_aliases_cnt * sizeof (uint32_t));
	184	addr_list_len = hst_resp.h_addr_list_cnt * INADDRSZ;
	185	recend = (const char *) found->data + found->recsize;
	186	/* Now check if we can trust hst_resp fields. If GC is
	187	in progress, it can contain anything. */
	188	if (mapped->head->gc_cycle != gc_cycle)
	189	{
	190	retval = -2;
	191	goto out;
	192	}
c207f23b UD	193
	194	#ifndef _STRING_ARCH_unaligned
	195	/* The aliases_len array in the mapped database might very
	196	well be unaligned. We will access it word-wise so on
	197	platforms which do not tolerate unaligned accesses we
	198	need to make an aligned copy. */
	199	if (((uintptr_t) aliases_len & (__alignof__ (*aliases_len) - 1))
	200	!= 0)
	201	{
1a77d37f	202	uint32_t *tmp = alloca (hst_resp.h_aliases_cnt
c207f23b UD	203	* sizeof (uint32_t));
c207f23b UD	204	aliases_len = memcpy (tmp, aliases_len,
1a77d37f	205	hst_resp.h_aliases_cnt
c207f23b UD	206	* sizeof (uint32_t));
	207	}
	208	#endif
	209	if (type != GETHOSTBYADDR && type != GETHOSTBYNAME)
	210	{
1a77d37f	211	if (hst_resp.h_length == INADDRSZ)
c207f23b	212	addr_list += addr_list_len;
1a77d37f	213	addr_list_len = hst_resp.h_addr_list_cnt * IN6ADDRSZ;
c207f23b	214	}
c207f23b UD	215	if (__builtin_expect ((const char *) addr_list + addr_list_len
c207f23b UD	216	> recend, 0))
1a77d37f	217	goto out;
c207f23b UD	218	}
	219	}
	220
1a77d37f	221	if (h_name == NULL)
c207f23b	222	{
1a77d37f JJ	223	sock = __nscd_open_socket (key, keylen, type, &hst_resp,
1a77d37f JJ	224	sizeof (hst_resp));
c207f23b UD	225	if (sock == -1)
	226	{
	227	__nss_not_use_nscd_hosts = 1;
4a4a65f2	228	goto out;
c207f23b	229	}
67479a70 UD	230	}
67479a70 UD	231
16aac663 UD	232	/* No value found so far. */
	233	*result = NULL;
	234
1a77d37f	235	if (__builtin_expect (hst_resp.found == -1, 0))
67479a70 UD	236	{
67479a70 UD	237	/* The daemon does not cache this database. */
67479a70	238	__nss_not_use_nscd_hosts = 1;
c207f23b	239	goto out_close;
67479a70 UD	240	}
67479a70 UD	241
1a77d37f	242	if (hst_resp.found == 1)
67479a70	243	{
67479a70	244	char *cp = buffer;
3810076f UD	245	uintptr_t align1;
3810076f UD	246	uintptr_t align2;
67479a70 UD	247	size_t total_len;
	248	ssize_t cnt;
	249	char *ignore;
	250	int n;
	251
49c091e5	252	/* A first check whether the buffer is sufficiently large is possible. */
67479a70	253	/* Now allocate the buffer the array for the group members. We must
3810076f UD	254	align the pointer and the base of the h_addr_list pointers. */
	255	align1 = ((__alignof__ (char ) - (cp - ((char ) 0)))
	256	& (__alignof__ (char *) - 1));
1a77d37f	257	align2 = ((__alignof__ (char *) - ((cp + align1 + hst_resp.h_name_len)
3810076f UD	258	- ((char *) 0)))
3810076f UD	259	& (__alignof__ (char *) - 1));
1a77d37f JJ	260	if (buflen < (align1 + hst_resp.h_name_len + align2
1a77d37f JJ	261	+ ((hst_resp.h_aliases_cnt + hst_resp.h_addr_list_cnt
c207f23b	262	+ 2)
67479a70	263	* sizeof (char *))
1a77d37f JJ	264	+ hst_resp.h_addr_list_cnt * (type == AF_INET
1a77d37f JJ	265	? INADDRSZ : IN6ADDRSZ)))
67479a70 UD	266	{
67479a70 UD	267	no_room:
4379b403	268	*h_errnop = NETDB_INTERNAL;
67479a70	269	__set_errno (ERANGE);
261eada2	270	retval = ERANGE;
c207f23b	271	goto out_close;
67479a70	272	}
3810076f	273	cp += align1;
67479a70 UD	274
	275	/* Prepare the result as far as we can. */
	276	resultbuf->h_aliases = (char **) cp;
1a77d37f	277	cp += (hst_resp.h_aliases_cnt + 1) * sizeof (char *);
67479a70	278	resultbuf->h_addr_list = (char **) cp;
1a77d37f	279	cp += (hst_resp.h_addr_list_cnt + 1) * sizeof (char *);
67479a70 UD	280
67479a70 UD	281	resultbuf->h_name = cp;
1a77d37f	282	cp += hst_resp.h_name_len + align2;
67479a70	283
67479a70 UD	284	if (type == GETHOSTBYADDR \|\| type == GETHOSTBYNAME)
67479a70 UD	285	{
67479a70 UD	286	resultbuf->h_addrtype = AF_INET;
67479a70 UD	287	resultbuf->h_length = INADDRSZ;
67479a70 UD	288	}
	289	else
	290	{
c207f23b UD	291	resultbuf->h_addrtype = AF_INET6;
	292	resultbuf->h_length = IN6ADDRSZ;
	293	}
1a77d37f	294	for (cnt = 0; cnt < hst_resp.h_addr_list_cnt; ++cnt)
c207f23b UD	295	{
	296	resultbuf->h_addr_list[cnt] = cp;
	297	cp += resultbuf->h_length;
	298	}
	299	resultbuf->h_addr_list[cnt] = NULL;
67479a70	300
c207f23b UD	301	if (h_name == NULL)
c207f23b UD	302	{
4a4a65f2 UD	303	struct iovec vec[4];
4a4a65f2 UD	304
c207f23b	305	vec[0].iov_base = resultbuf->h_name;
1a77d37f JJ	306	vec[0].iov_len = hst_resp.h_name_len;
1a77d37f JJ	307	total_len = hst_resp.h_name_len;
c207f23b	308	n = 1;
67479a70	309
1a77d37f	310	if (hst_resp.h_aliases_cnt > 0)
c207f23b	311	{
1a77d37f	312	aliases_len = alloca (hst_resp.h_aliases_cnt
c207f23b UD	313	* sizeof (uint32_t));
c207f23b UD	314	vec[n].iov_base = (void *) aliases_len;
1a77d37f	315	vec[n].iov_len = hst_resp.h_aliases_cnt * sizeof (uint32_t);
67479a70	316
1a77d37f	317	total_len += hst_resp.h_aliases_cnt * sizeof (uint32_t);
c207f23b UD	318	++n;
c207f23b UD	319	}
67479a70	320
c207f23b	321	if (type == GETHOSTBYADDR \|\| type == GETHOSTBYNAME)
67479a70	322	{
c207f23b	323	vec[n].iov_base = resultbuf->h_addr_list[0];
1a77d37f	324	vec[n].iov_len = hst_resp.h_addr_list_cnt * INADDRSZ;
c207f23b	325
1a77d37f	326	total_len += hst_resp.h_addr_list_cnt * INADDRSZ;
c207f23b UD	327
c207f23b UD	328	++n;
67479a70	329	}
c207f23b UD	330	else
c207f23b UD	331	{
1a77d37f	332	if (hst_resp.h_length == INADDRSZ)
c207f23b	333	{
1a77d37f	334	ignore = alloca (hst_resp.h_addr_list_cnt * INADDRSZ);
c207f23b	335	vec[n].iov_base = ignore;
1a77d37f	336	vec[n].iov_len = hst_resp.h_addr_list_cnt * INADDRSZ;
67479a70	337
1a77d37f	338	total_len += hst_resp.h_addr_list_cnt * INADDRSZ;
67479a70	339
c207f23b UD	340	++n;
c207f23b UD	341	}
67479a70	342
c207f23b	343	vec[n].iov_base = resultbuf->h_addr_list[0];
1a77d37f	344	vec[n].iov_len = hst_resp.h_addr_list_cnt * IN6ADDRSZ;
67479a70	345
1a77d37f	346	total_len += hst_resp.h_addr_list_cnt * IN6ADDRSZ;
c207f23b UD	347
	348	++n;
	349	}
	350
d2dc7d84	351	if ((size_t) __readvall (sock, vec, n) != total_len)
c207f23b UD	352	goto out_close;
	353	}
	354	else
	355	{
1a77d37f	356	memcpy (resultbuf->h_name, h_name, hst_resp.h_name_len);
c207f23b UD	357	memcpy (resultbuf->h_addr_list[0], addr_list, addr_list_len);
c207f23b UD	358	}
67479a70 UD	359
	360	/* Now we also can read the aliases. */
	361	total_len = 0;
1a77d37f	362	for (cnt = 0; cnt < hst_resp.h_aliases_cnt; ++cnt)
67479a70 UD	363	{
	364	resultbuf->h_aliases[cnt] = cp;
	365	cp += aliases_len[cnt];
	366	total_len += aliases_len[cnt];
	367	}
	368	resultbuf->h_aliases[cnt] = NULL;
	369
c207f23b UD	370	if (__builtin_expect ((const char *) addr_list + addr_list_len
c207f23b UD	371	+ total_len > recend, 0))
1a77d37f JJ	372	{
	373	/* aliases_len array might contain garbage during nscd GC cycle,
	374	retry rather than fail in that case. */
	375	if (addr_list != NULL && mapped->head->gc_cycle != gc_cycle)
	376	retval = -2;
	377	goto out_close;
	378	}
67479a70	379	/* See whether this would exceed the buffer capacity. */
c207f23b	380	if (__builtin_expect (cp > buffer + buflen, 0))
1a77d37f JJ	381	{
	382	/* aliases_len array might contain garbage during nscd GC cycle,
	383	retry rather than fail in that case. */
	384	if (addr_list != NULL && mapped->head->gc_cycle != gc_cycle)
	385	{
	386	retval = -2;
	387	goto out_close;
	388	}
	389	goto no_room;
	390	}
67479a70 UD	391
67479a70 UD	392	/* And finally read the aliases. */
c207f23b UD	393	if (addr_list == NULL)
c207f23b UD	394	{
74ac0a89 UD	395	if (total_len == 0
	396	\|\| ((size_t) __readall (sock, resultbuf->h_aliases[0], total_len)
	397	== total_len))
c207f23b UD	398	{
	399	retval = 0;
	400	*result = resultbuf;
	401	}
	402	}
	403	else
261eada2	404	{
c207f23b UD	405	memcpy (resultbuf->h_aliases[0],
	406	(const char *) addr_list + addr_list_len, total_len);
	407
5429ff76	408	/* Try to detect corrupt databases. */
1a77d37f JJ	409	if (resultbuf->h_name[hst_resp.h_name_len - 1] != '\0'
1a77d37f JJ	410	\|\| ({for (cnt = 0; cnt < hst_resp.h_aliases_cnt; ++cnt)
5429ff76 UD	411	if (resultbuf->h_aliases[cnt][aliases_len[cnt] - 1]
	412	!= '\0')
	413	break;
1a77d37f JJ	414	cnt < hst_resp.h_aliases_cnt; }))
	415	{
	416	/* We cannot use the database. */
	417	if (mapped->head->gc_cycle != gc_cycle)
	418	retval = -2;
	419	goto out_close;
	420	}
5429ff76	421
261eada2 UD	422	retval = 0;
	423	*result = resultbuf;
	424	}
67479a70 UD	425	}
	426	else
	427	{
	428	/* Store the error number. */
1a77d37f	429	*h_errnop = hst_resp.error;
67479a70	430
cfca0aa3 UD	431	/* Set errno to 0 to indicate no error, just no found record. */
cfca0aa3 UD	432	__set_errno (0);
261eada2 UD	433	/* Even though we have not found anything, the result is zero. */
261eada2 UD	434	retval = 0;
67479a70	435	}
12c80513	436
c207f23b UD	437	out_close:
	438	if (sock != -1)
	439	close_not_cancel_no_status (sock);
12c80513	440	out:
1a77d37f	441	if (__nscd_drop_map_ref (mapped, &gc_cycle) != 0)
0891f970 UD	442	{
	443	/* When we come here this means there has been a GC cycle while we
	444	were looking for the data. This means the data might have been
	445	inconsistent. Retry if possible. */
1a77d37f	446	if ((gc_cycle & 1) != 0 \|\| ++nretries == 5 \|\| retval == -1)
0891f970 UD	447	{
0891f970 UD	448	/* nscd is just running gc now. Disable using the mapping. */
1a77d37f JJ	449	if (atomic_decrement_val (&mapped->counter) == 0)
1a77d37f JJ	450	__nscd_unmap (mapped);
0891f970 UD	451	mapped = NO_MAPPING;
	452	}
	453
1a77d37f JJ	454	if (retval != -1)
1a77d37f JJ	455	goto retry;
0891f970	456	}
12c80513	457
261eada2	458	return retval;
67479a70	459	}