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

/* Copyright (C) 1998-2023 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/>.  */

#include <errno.h>
#include <resolv/resolv-internal.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);


int
__nscd_gethostbyname_r (const char *name, struct hostent *resultbuf,
			char *buffer, size_t buflen, struct hostent **result,
			int *h_errnop)
{
  return nscd_gethst_r (name, strlen (name) + 1, GETHOSTBYNAME, 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.  */
void
__nscd_hst_map_freemem (void)
{
  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 < time64_now ()))
    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
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 (__glibc_unlikely (__nss_have_localdomain >= 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;
	    }

	  /* 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));
	    }
	  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 (__glibc_unlikely (hst_resp.found == -1))
    {
      /* 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 *) - ((uintptr_t) cp))
		& (__alignof__ (char *) - 1));
      align2 = ((__alignof__ (char *) - ((uintptr_t) (cp + align1 + hst_resp.h_name_len)))
		& (__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 (__glibc_unlikely (cp > buffer + buflen))
	{
	  /* 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_nocancel_nostatus (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_fetch_add_relaxed (&mapped->counter, -1) == 1)
	    __nscd_unmap (mapped);
	  mapped = NO_MAPPING;
	}

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

  return retval;
}
Commit	Line	Data
6d7e8eda	1	/* Copyright (C) 1998-2023 Free Software Foundation, Inc.
67479a70	2	This file is part of the GNU C Library.
67479a70 UD	3
67479a70 UD	4	The GNU C Library is free software; you can redistribute it and/or
41bdb6e2 AJ	5	modify it under the terms of the GNU Lesser General Public
	6	License as published by the Free Software Foundation; either
	7	version 2.1 of the License, or (at your option) any later version.
67479a70 UD	8
	9	The GNU C Library is distributed in the hope that it will be useful,
	10	but WITHOUT ANY WARRANTY; without even the implied warranty of
	11	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
41bdb6e2	12	Lesser General Public License for more details.
67479a70	13
41bdb6e2	14	You should have received a copy of the GNU Lesser General Public
59ba27a6	15	License along with the GNU C Library; if not, see
5a82c748	16	<https://www.gnu.org/licenses/>. */
67479a70 UD	17
67479a70 UD	18	#include <errno.h>
b76e0659	19	#include <resolv/resolv-internal.h>
67479a70	20	#include <stdio.h>
67479a70	21	#include <string.h>
e054f494	22	#include <stdint.h>
67479a70	23	#include <arpa/nameser.h>
40c38b6c	24	#include <not-cancel.h>
67479a70	25
3f804c95	26	#include "nscd-client.h"
67479a70 UD	27	#include "nscd_proto.h"
	28
	29	int __nss_not_use_nscd_hosts;
	30
	31	static int nscd_gethst_r (const char *key, size_t keylen, request_type type,
	32	struct hostent resultbuf, char buffer,
261eada2	33	size_t buflen, struct hostent **result,
75b3047e	34	int *h_errnop);
67479a70 UD	35
	36
	37	int
	38	__nscd_gethostbyname_r (const char name, struct hostent resultbuf,
261eada2 UD	39	char buffer, size_t buflen, struct hostent *result,
261eada2 UD	40	int *h_errnop)
67479a70	41	{
3f8b44be	42	return nscd_gethst_r (name, strlen (name) + 1, GETHOSTBYNAME, resultbuf,
261eada2	43	buffer, buflen, result, h_errnop);
67479a70 UD	44	}
	45
	46
	47	int
	48	__nscd_gethostbyname2_r (const char name, int af, struct hostent resultbuf,
261eada2 UD	49	char buffer, size_t buflen, struct hostent *result,
261eada2 UD	50	int *h_errnop)
67479a70 UD	51	{
	52	request_type reqtype;
	53
	54	reqtype = af == AF_INET6 ? GETHOSTBYNAMEv6 : GETHOSTBYNAME;
	55
	56	return nscd_gethst_r (name, strlen (name) + 1, reqtype, resultbuf,
261eada2	57	buffer, buflen, result, h_errnop);
67479a70 UD	58	}
	59
	60
	61	int
9d4d69b8	62	__nscd_gethostbyaddr_r (const void *addr, socklen_t len, int type,
67479a70	63	struct hostent resultbuf, char buffer, size_t buflen,
261eada2	64	struct hostent *result, int h_errnop)
67479a70 UD	65	{
	66	request_type reqtype;
	67
	68	if (!((len == INADDRSZ && type == AF_INET)
	69	\|\| (len == IN6ADDRSZ && type == AF_INET6)))
	70	/* LEN and TYPE do not match. */
1670698f	71	return -1;
67479a70 UD	72
	73	reqtype = type == AF_INET6 ? GETHOSTBYADDRv6 : GETHOSTBYADDR;
	74
261eada2	75	return nscd_gethst_r (addr, len, reqtype, resultbuf, buffer, buflen, result,
67479a70 UD	76	h_errnop);
	77	}
	78
	79
6f8a7dff	80	libc_locked_map_ptr (, __hst_map_handle) attribute_hidden;
c207f23b UD	81	/* Note that we only free the structure if necessary. The memory
	82	mapping is not removed since it is not visible to the malloc
	83	handling. */
88677348 AZN	84	void
88677348 AZN	85	__nscd_hst_map_freemem (void)
67479a70	86	{
ed2ced8a UD	87	if (__hst_map_handle.mapped != NO_MAPPING)
	88	{
	89	void *p = __hst_map_handle.mapped;
	90	__hst_map_handle.mapped = NO_MAPPING;
	91	free (p);
	92	}
67479a70 UD	93	}
	94
	95
3a2c0242 UD	96	uint32_t
	97	__nscd_get_nl_timestamp (void)
	98	{
509072a0	99	uint32_t retval;
3a2c0242 UD	100	if (__nss_not_use_nscd_hosts != 0)
	101	return 0;
	102
509072a0 AJ	103	/* __nscd_get_mapping can change hst_map_handle.mapped to NO_MAPPING.
	104	However, __nscd_get_mapping assumes the prior value was not NO_MAPPING.
	105	Thus we have to acquire the lock to prevent this thread from changing
	106	hst_map_handle.mapped to NO_MAPPING while another thread is inside
	107	__nscd_get_mapping. */
	108	if (!__nscd_acquire_maplock (&__hst_map_handle))
	109	return 0;
	110
3a2c0242 UD	111	struct mapped_database *map = __hst_map_handle.mapped;
	112
	113	if (map == NULL
	114	\|\| (map != NO_MAPPING
	115	&& map->head->nscd_certainly_running == 0
fa4a1927	116	&& map->head->timestamp + MAPPING_TIMEOUT < time64_now ()))
3a2c0242 UD	117	map = __nscd_get_mapping (GETFDHST, "hosts", &__hst_map_handle.mapped);
	118
	119	if (map == NO_MAPPING)
509072a0 AJ	120	retval = 0;
	121	else
	122	retval = map->head->extra_data[NSCD_HST_IDX_CONF_TIMESTAMP];
	123
	124	/* Release the lock. */
	125	__hst_map_handle.lock = 0;
3a2c0242	126
509072a0	127	return retval;
3a2c0242 UD	128	}
	129
	130
50e481ce UD	131	int __nss_have_localdomain attribute_hidden;
50e481ce UD	132
67479a70 UD	133	static int
	134	nscd_gethst_r (const char *key, size_t keylen, request_type type,
	135	struct hostent resultbuf, char buffer, size_t buflen,
261eada2	136	struct hostent *result, int h_errnop)
67479a70	137	{
a1ffb40e	138	if (__glibc_unlikely (__nss_have_localdomain >= 0))
50e481ce UD	139	{
	140	if (__nss_have_localdomain == 0)
	141	__nss_have_localdomain = getenv ("LOCALDOMAIN") != NULL ? 1 : -1;
	142	if (__nss_have_localdomain > 0)
	143	{
	144	__nss_not_use_nscd_hosts = 1;
	145	return -1;
	146	}
	147	}
	148
0891f970 UD	149	int gc_cycle;
	150	int nretries = 0;
	151
	152	/* If the mapping is available, try to search there instead of
	153	communicating with the nscd. */
	154	struct mapped_database *mapped;
ed2ced8a UD	155	mapped = __nscd_get_map_ref (GETFDHST, "hosts", &__hst_map_handle,
ed2ced8a UD	156	&gc_cycle);
0891f970 UD	157
0891f970 UD	158	retry:;
c207f23b UD	159	const char *h_name = NULL;
	160	const uint32_t *aliases_len = NULL;
	161	const char *addr_list = NULL;
	162	size_t addr_list_len = 0;
	163	int retval = -1;
c207f23b UD	164	const char recend = (const char ) ~UINTMAX_C (0);
c207f23b UD	165	int sock = -1;
1a77d37f	166	hst_response_header hst_resp;
af38d7ce	167	if (mapped != NO_MAPPING)
67479a70	168	{
1a77d37f	169	/* No const qualifier, as it can change during garbage collection. */
cfe1fc10 JJ	170	struct datahead *found = __nscd_cache_search (type, key, keylen, mapped,
cfe1fc10 JJ	171	sizeof hst_resp);
c207f23b UD	172	if (found != NULL)
c207f23b UD	173	{
1a77d37f JJ	174	h_name = (char *) (&found->data[0].hstdata + 1);
	175	hst_resp = found->data[0].hstdata;
	176	aliases_len = (uint32_t *) (h_name + hst_resp.h_name_len);
c207f23b	177	addr_list = ((char *) aliases_len
1a77d37f JJ	178	+ hst_resp.h_aliases_cnt * sizeof (uint32_t));
	179	addr_list_len = hst_resp.h_addr_list_cnt * INADDRSZ;
	180	recend = (const char *) found->data + found->recsize;
	181	/* Now check if we can trust hst_resp fields. If GC is
	182	in progress, it can contain anything. */
	183	if (mapped->head->gc_cycle != gc_cycle)
	184	{
	185	retval = -2;
	186	goto out;
	187	}
c207f23b	188
c207f23b UD	189	/* The aliases_len array in the mapped database might very
	190	well be unaligned. We will access it word-wise so on
	191	platforms which do not tolerate unaligned accesses we
	192	need to make an aligned copy. */
	193	if (((uintptr_t) aliases_len & (__alignof__ (*aliases_len) - 1))
	194	!= 0)
	195	{
1a77d37f	196	uint32_t *tmp = alloca (hst_resp.h_aliases_cnt
c207f23b UD	197	* sizeof (uint32_t));
c207f23b UD	198	aliases_len = memcpy (tmp, aliases_len,
1a77d37f	199	hst_resp.h_aliases_cnt
c207f23b UD	200	* sizeof (uint32_t));
c207f23b UD	201	}
c207f23b UD	202	if (type != GETHOSTBYADDR && type != GETHOSTBYNAME)
c207f23b UD	203	{
1a77d37f	204	if (hst_resp.h_length == INADDRSZ)
c207f23b	205	addr_list += addr_list_len;
1a77d37f	206	addr_list_len = hst_resp.h_addr_list_cnt * IN6ADDRSZ;
c207f23b	207	}
c207f23b UD	208	if (__builtin_expect ((const char *) addr_list + addr_list_len
c207f23b UD	209	> recend, 0))
1a77d37f	210	goto out;
c207f23b UD	211	}
	212	}
	213
1a77d37f	214	if (h_name == NULL)
c207f23b	215	{
1a77d37f JJ	216	sock = __nscd_open_socket (key, keylen, type, &hst_resp,
1a77d37f JJ	217	sizeof (hst_resp));
c207f23b UD	218	if (sock == -1)
	219	{
	220	__nss_not_use_nscd_hosts = 1;
4a4a65f2	221	goto out;
c207f23b	222	}
67479a70 UD	223	}
67479a70 UD	224
16aac663 UD	225	/* No value found so far. */
	226	*result = NULL;
	227
a1ffb40e	228	if (__glibc_unlikely (hst_resp.found == -1))
67479a70 UD	229	{
67479a70 UD	230	/* The daemon does not cache this database. */
67479a70	231	__nss_not_use_nscd_hosts = 1;
c207f23b	232	goto out_close;
67479a70 UD	233	}
67479a70 UD	234
1a77d37f	235	if (hst_resp.found == 1)
67479a70	236	{
67479a70	237	char *cp = buffer;
3810076f UD	238	uintptr_t align1;
3810076f UD	239	uintptr_t align2;
67479a70 UD	240	size_t total_len;
	241	ssize_t cnt;
	242	char *ignore;
	243	int n;
	244
49c091e5	245	/* A first check whether the buffer is sufficiently large is possible. */
67479a70	246	/* Now allocate the buffer the array for the group members. We must
3810076f	247	align the pointer and the base of the h_addr_list pointers. */
cc4d6614	248	align1 = ((__alignof__ (char *) - ((uintptr_t) cp))
3810076f	249	& (__alignof__ (char *) - 1));
cc4d6614	250	align2 = ((__alignof__ (char *) - ((uintptr_t) (cp + align1 + hst_resp.h_name_len)))
3810076f	251	& (__alignof__ (char *) - 1));
1a77d37f JJ	252	if (buflen < (align1 + hst_resp.h_name_len + align2
1a77d37f JJ	253	+ ((hst_resp.h_aliases_cnt + hst_resp.h_addr_list_cnt
c207f23b	254	+ 2)
67479a70	255	* sizeof (char *))
1a77d37f JJ	256	+ hst_resp.h_addr_list_cnt * (type == AF_INET
1a77d37f JJ	257	? INADDRSZ : IN6ADDRSZ)))
67479a70 UD	258	{
67479a70 UD	259	no_room:
4379b403	260	*h_errnop = NETDB_INTERNAL;
67479a70	261	__set_errno (ERANGE);
261eada2	262	retval = ERANGE;
c207f23b	263	goto out_close;
67479a70	264	}
3810076f	265	cp += align1;
67479a70 UD	266
	267	/* Prepare the result as far as we can. */
	268	resultbuf->h_aliases = (char **) cp;
1a77d37f	269	cp += (hst_resp.h_aliases_cnt + 1) * sizeof (char *);
67479a70	270	resultbuf->h_addr_list = (char **) cp;
1a77d37f	271	cp += (hst_resp.h_addr_list_cnt + 1) * sizeof (char *);
67479a70 UD	272
67479a70 UD	273	resultbuf->h_name = cp;
1a77d37f	274	cp += hst_resp.h_name_len + align2;
67479a70	275
67479a70 UD	276	if (type == GETHOSTBYADDR \|\| type == GETHOSTBYNAME)
67479a70 UD	277	{
67479a70 UD	278	resultbuf->h_addrtype = AF_INET;
67479a70 UD	279	resultbuf->h_length = INADDRSZ;
67479a70 UD	280	}
	281	else
	282	{
c207f23b UD	283	resultbuf->h_addrtype = AF_INET6;
	284	resultbuf->h_length = IN6ADDRSZ;
	285	}
1a77d37f	286	for (cnt = 0; cnt < hst_resp.h_addr_list_cnt; ++cnt)
c207f23b UD	287	{
	288	resultbuf->h_addr_list[cnt] = cp;
	289	cp += resultbuf->h_length;
	290	}
	291	resultbuf->h_addr_list[cnt] = NULL;
67479a70	292
c207f23b UD	293	if (h_name == NULL)
c207f23b UD	294	{
4a4a65f2 UD	295	struct iovec vec[4];
4a4a65f2 UD	296
c207f23b	297	vec[0].iov_base = resultbuf->h_name;
1a77d37f JJ	298	vec[0].iov_len = hst_resp.h_name_len;
1a77d37f JJ	299	total_len = hst_resp.h_name_len;
c207f23b	300	n = 1;
67479a70	301
1a77d37f	302	if (hst_resp.h_aliases_cnt > 0)
c207f23b	303	{
1a77d37f	304	aliases_len = alloca (hst_resp.h_aliases_cnt
c207f23b UD	305	* sizeof (uint32_t));
c207f23b UD	306	vec[n].iov_base = (void *) aliases_len;
1a77d37f	307	vec[n].iov_len = hst_resp.h_aliases_cnt * sizeof (uint32_t);
67479a70	308
1a77d37f	309	total_len += hst_resp.h_aliases_cnt * sizeof (uint32_t);
c207f23b UD	310	++n;
c207f23b UD	311	}
67479a70	312
c207f23b	313	if (type == GETHOSTBYADDR \|\| type == GETHOSTBYNAME)
67479a70	314	{
c207f23b	315	vec[n].iov_base = resultbuf->h_addr_list[0];
1a77d37f	316	vec[n].iov_len = hst_resp.h_addr_list_cnt * INADDRSZ;
c207f23b	317
1a77d37f	318	total_len += hst_resp.h_addr_list_cnt * INADDRSZ;
c207f23b UD	319
c207f23b UD	320	++n;
67479a70	321	}
c207f23b UD	322	else
c207f23b UD	323	{
1a77d37f	324	if (hst_resp.h_length == INADDRSZ)
c207f23b	325	{
1a77d37f	326	ignore = alloca (hst_resp.h_addr_list_cnt * INADDRSZ);
c207f23b	327	vec[n].iov_base = ignore;
1a77d37f	328	vec[n].iov_len = hst_resp.h_addr_list_cnt * INADDRSZ;
67479a70	329
1a77d37f	330	total_len += hst_resp.h_addr_list_cnt * INADDRSZ;
67479a70	331
c207f23b UD	332	++n;
c207f23b UD	333	}
67479a70	334
c207f23b	335	vec[n].iov_base = resultbuf->h_addr_list[0];
1a77d37f	336	vec[n].iov_len = hst_resp.h_addr_list_cnt * IN6ADDRSZ;
67479a70	337
1a77d37f	338	total_len += hst_resp.h_addr_list_cnt * IN6ADDRSZ;
c207f23b UD	339
	340	++n;
	341	}
	342
d2dc7d84	343	if ((size_t) __readvall (sock, vec, n) != total_len)
c207f23b UD	344	goto out_close;
	345	}
	346	else
	347	{
1a77d37f	348	memcpy (resultbuf->h_name, h_name, hst_resp.h_name_len);
c207f23b UD	349	memcpy (resultbuf->h_addr_list[0], addr_list, addr_list_len);
c207f23b UD	350	}
67479a70 UD	351
	352	/* Now we also can read the aliases. */
	353	total_len = 0;
1a77d37f	354	for (cnt = 0; cnt < hst_resp.h_aliases_cnt; ++cnt)
67479a70 UD	355	{
	356	resultbuf->h_aliases[cnt] = cp;
	357	cp += aliases_len[cnt];
	358	total_len += aliases_len[cnt];
	359	}
	360	resultbuf->h_aliases[cnt] = NULL;
	361
c207f23b UD	362	if (__builtin_expect ((const char *) addr_list + addr_list_len
c207f23b UD	363	+ total_len > recend, 0))
1a77d37f JJ	364	{
	365	/* aliases_len array might contain garbage during nscd GC cycle,
	366	retry rather than fail in that case. */
	367	if (addr_list != NULL && mapped->head->gc_cycle != gc_cycle)
	368	retval = -2;
	369	goto out_close;
	370	}
67479a70	371	/* See whether this would exceed the buffer capacity. */
a1ffb40e	372	if (__glibc_unlikely (cp > buffer + buflen))
1a77d37f JJ	373	{
	374	/* aliases_len array might contain garbage during nscd GC cycle,
	375	retry rather than fail in that case. */
	376	if (addr_list != NULL && mapped->head->gc_cycle != gc_cycle)
	377	{
	378	retval = -2;
	379	goto out_close;
	380	}
	381	goto no_room;
	382	}
67479a70 UD	383
67479a70 UD	384	/* And finally read the aliases. */
c207f23b UD	385	if (addr_list == NULL)
c207f23b UD	386	{
74ac0a89 UD	387	if (total_len == 0
	388	\|\| ((size_t) __readall (sock, resultbuf->h_aliases[0], total_len)
	389	== total_len))
c207f23b UD	390	{
	391	retval = 0;
	392	*result = resultbuf;
	393	}
	394	}
	395	else
261eada2	396	{
c207f23b UD	397	memcpy (resultbuf->h_aliases[0],
	398	(const char *) addr_list + addr_list_len, total_len);
	399
5429ff76	400	/* Try to detect corrupt databases. */
1a77d37f JJ	401	if (resultbuf->h_name[hst_resp.h_name_len - 1] != '\0'
1a77d37f JJ	402	\|\| ({for (cnt = 0; cnt < hst_resp.h_aliases_cnt; ++cnt)
5429ff76 UD	403	if (resultbuf->h_aliases[cnt][aliases_len[cnt] - 1]
	404	!= '\0')
	405	break;
1a77d37f JJ	406	cnt < hst_resp.h_aliases_cnt; }))
	407	{
	408	/* We cannot use the database. */
	409	if (mapped->head->gc_cycle != gc_cycle)
	410	retval = -2;
	411	goto out_close;
	412	}
5429ff76	413
261eada2 UD	414	retval = 0;
	415	*result = resultbuf;
	416	}
67479a70 UD	417	}
	418	else
	419	{
	420	/* Store the error number. */
1a77d37f	421	*h_errnop = hst_resp.error;
67479a70	422
cfca0aa3 UD	423	/* Set errno to 0 to indicate no error, just no found record. */
cfca0aa3 UD	424	__set_errno (0);
261eada2 UD	425	/* Even though we have not found anything, the result is zero. */
261eada2 UD	426	retval = 0;
67479a70	427	}
12c80513	428
c207f23b UD	429	out_close:
c207f23b UD	430	if (sock != -1)
c181840c	431	__close_nocancel_nostatus (sock);
12c80513	432	out:
1a77d37f	433	if (__nscd_drop_map_ref (mapped, &gc_cycle) != 0)
0891f970 UD	434	{
	435	/* When we come here this means there has been a GC cycle while we
	436	were looking for the data. This means the data might have been
	437	inconsistent. Retry if possible. */
1a77d37f	438	if ((gc_cycle & 1) != 0 \|\| ++nretries == 5 \|\| retval == -1)
0891f970 UD	439	{
0891f970 UD	440	/* nscd is just running gc now. Disable using the mapping. */
a364a3a7	441	if (atomic_fetch_add_relaxed (&mapped->counter, -1) == 1)
1a77d37f	442	__nscd_unmap (mapped);
0891f970 UD	443	mapped = NO_MAPPING;
	444	}
	445
1a77d37f JJ	446	if (retval != -1)
1a77d37f JJ	447	goto retry;
0891f970	448	}
12c80513	449
261eada2	450	return retval;
67479a70	451	}