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496 lines
14 KiB
C
496 lines
14 KiB
C
/* Hosts file parser in nss_files module.
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Copyright (C) 1996-2014 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#include <assert.h>
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#include <netinet/in.h>
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#include <arpa/inet.h>
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#include <arpa/nameser.h>
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#include <netdb.h>
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#include <resolv.h>
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/* Get implementation for some internal functions. */
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#include "../resolv/mapv4v6addr.h"
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#include "../resolv/res_hconf.h"
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#define ENTNAME hostent
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#define DATABASE "hosts"
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#define NEED_H_ERRNO
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#define EXTRA_ARGS , af, flags
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#define EXTRA_ARGS_DECL , int af, int flags
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#define ENTDATA hostent_data
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struct hostent_data
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{
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unsigned char host_addr[16]; /* IPv4 or IPv6 address. */
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char *h_addr_ptrs[2]; /* Points to that and null terminator. */
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};
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#define TRAILING_LIST_MEMBER h_aliases
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#define TRAILING_LIST_SEPARATOR_P isspace
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#include "files-parse.c"
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LINE_PARSER
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("#",
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{
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char *addr;
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STRING_FIELD (addr, isspace, 1);
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/* Parse address. */
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if (inet_pton (af == AF_UNSPEC ? AF_INET : af, addr, entdata->host_addr)
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> 0)
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af = af == AF_UNSPEC ? AF_INET : af;
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else
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{
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if (af == AF_INET6 && (flags & AI_V4MAPPED) != 0
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&& inet_pton (AF_INET, addr, entdata->host_addr) > 0)
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map_v4v6_address ((char *) entdata->host_addr,
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(char *) entdata->host_addr);
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else if (af == AF_INET
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&& inet_pton (AF_INET6, addr, entdata->host_addr) > 0)
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{
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if (IN6_IS_ADDR_V4MAPPED (entdata->host_addr))
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memcpy (entdata->host_addr, entdata->host_addr + 12, INADDRSZ);
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else if (IN6_IS_ADDR_LOOPBACK (entdata->host_addr))
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{
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in_addr_t localhost = htonl (INADDR_LOOPBACK);
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memcpy (entdata->host_addr, &localhost, sizeof (localhost));
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}
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else
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/* Illegal address: ignore line. */
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return 0;
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}
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else if (af == AF_UNSPEC
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&& inet_pton (AF_INET6, addr, entdata->host_addr) > 0)
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af = AF_INET6;
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else
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/* Illegal address: ignore line. */
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return 0;
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}
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/* We always return entries of the requested form. */
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result->h_addrtype = af;
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result->h_length = af == AF_INET ? INADDRSZ : IN6ADDRSZ;
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/* Store a pointer to the address in the expected form. */
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entdata->h_addr_ptrs[0] = (char *) entdata->host_addr;
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entdata->h_addr_ptrs[1] = NULL;
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result->h_addr_list = entdata->h_addr_ptrs;
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STRING_FIELD (result->h_name, isspace, 1);
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})
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#define EXTRA_ARGS_VALUE \
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, ((_res.options & RES_USE_INET6) ? AF_INET6 : AF_INET), \
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((_res.options & RES_USE_INET6) ? AI_V4MAPPED : 0)
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#include "files-XXX.c"
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#undef EXTRA_ARGS_VALUE
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/* We only need to consider IPv4 mapped addresses if the input to the
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gethostbyaddr() function is an IPv6 address. */
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#define EXTRA_ARGS_VALUE \
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, af, (len == IN6ADDRSZ ? AI_V4MAPPED : 0)
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DB_LOOKUP (hostbyaddr, ,,,
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{
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if (result->h_length == (int) len
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&& ! memcmp (addr, result->h_addr_list[0], len))
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break;
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}, const void *addr, socklen_t len, int af)
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#undef EXTRA_ARGS_VALUE
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enum nss_status
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_nss_files_gethostbyname3_r (const char *name, int af, struct hostent *result,
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char *buffer, size_t buflen, int *errnop,
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int *herrnop, int32_t *ttlp, char **canonp)
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{
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uintptr_t pad = -(uintptr_t) buffer % __alignof__ (struct hostent_data);
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buffer += pad;
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buflen = buflen > pad ? buflen - pad : 0;
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__libc_lock_lock (lock);
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/* Reset file pointer to beginning or open file. */
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enum nss_status status = internal_setent (keep_stream);
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if (status == NSS_STATUS_SUCCESS)
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{
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/* XXX Is using _res to determine whether we want to convert IPv4
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addresses to IPv6 addresses really the right thing to do? */
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int flags = ((_res.options & RES_USE_INET6) ? AI_V4MAPPED : 0);
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/* Tell getent function that we have repositioned the file pointer. */
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last_use = getby;
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while ((status = internal_getent (result, buffer, buflen, errnop,
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herrnop, af, flags))
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== NSS_STATUS_SUCCESS)
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{
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LOOKUP_NAME_CASE (h_name, h_aliases)
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}
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if (status == NSS_STATUS_SUCCESS
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&& _res_hconf.flags & HCONF_FLAG_MULTI)
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{
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/* We have to get all host entries from the file. */
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size_t tmp_buflen = MIN (buflen, 4096);
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char tmp_buffer_stack[tmp_buflen]
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__attribute__ ((__aligned__ (__alignof__ (struct hostent_data))));
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char *tmp_buffer = tmp_buffer_stack;
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struct hostent tmp_result_buf;
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int naddrs = 1;
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int naliases = 0;
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char *bufferend;
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bool tmp_buffer_malloced = false;
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while (result->h_aliases[naliases] != NULL)
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++naliases;
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bufferend = (char *) &result->h_aliases[naliases + 1];
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again:
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while ((status = internal_getent (&tmp_result_buf, tmp_buffer,
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tmp_buflen, errnop, herrnop, af,
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flags))
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== NSS_STATUS_SUCCESS)
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{
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int matches = 1;
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struct hostent *old_result = result;
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result = &tmp_result_buf;
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/* The following piece is a bit clumsy but we want to use the
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`LOOKUP_NAME_CASE' value. The optimizer should do its
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job. */
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do
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{
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LOOKUP_NAME_CASE (h_name, h_aliases)
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result = old_result;
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}
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while ((matches = 0));
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if (matches)
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{
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/* We could be very clever and try to recycle a few bytes
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in the buffer instead of generating new arrays. But
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we are not doing this here since it's more work than
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it's worth. Simply let the user provide a bit bigger
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buffer. */
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char **new_h_addr_list;
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char **new_h_aliases;
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int newaliases = 0;
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size_t newstrlen = 0;
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int cnt;
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/* Count the new aliases and the length of the strings. */
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while (tmp_result_buf.h_aliases[newaliases] != NULL)
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{
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char *cp = tmp_result_buf.h_aliases[newaliases];
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++newaliases;
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newstrlen += strlen (cp) + 1;
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}
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/* If the real name is different add it also to the
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aliases. This means that there is a duplication
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in the alias list but this is really the user's
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problem. */
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if (strcmp (old_result->h_name,
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tmp_result_buf.h_name) != 0)
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{
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++newaliases;
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newstrlen += strlen (tmp_result_buf.h_name) + 1;
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}
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/* Make sure bufferend is aligned. */
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assert ((bufferend - (char *) 0) % sizeof (char *) == 0);
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/* Now we can check whether the buffer is large enough.
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16 is the maximal size of the IP address. */
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if (bufferend + 16 + (naddrs + 2) * sizeof (char *)
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+ roundup (newstrlen, sizeof (char *))
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+ (naliases + newaliases + 1) * sizeof (char *)
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>= buffer + buflen)
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{
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*errnop = ERANGE;
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*herrnop = NETDB_INTERNAL;
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status = NSS_STATUS_TRYAGAIN;
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goto out;
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}
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new_h_addr_list =
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(char **) (bufferend
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+ roundup (newstrlen, sizeof (char *))
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+ 16);
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new_h_aliases =
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(char **) ((char *) new_h_addr_list
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+ (naddrs + 2) * sizeof (char *));
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/* Copy the old data in the new arrays. */
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for (cnt = 0; cnt < naddrs; ++cnt)
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new_h_addr_list[cnt] = old_result->h_addr_list[cnt];
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for (cnt = 0; cnt < naliases; ++cnt)
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new_h_aliases[cnt] = old_result->h_aliases[cnt];
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/* Store the new strings. */
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cnt = 0;
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while (tmp_result_buf.h_aliases[cnt] != NULL)
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{
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new_h_aliases[naliases++] = bufferend;
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bufferend = (__stpcpy (bufferend,
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tmp_result_buf.h_aliases[cnt])
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+ 1);
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++cnt;
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}
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if (cnt < newaliases)
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{
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new_h_aliases[naliases++] = bufferend;
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bufferend = __stpcpy (bufferend,
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tmp_result_buf.h_name) + 1;
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}
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/* Final NULL pointer. */
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new_h_aliases[naliases] = NULL;
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/* Round up the buffer end address. */
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bufferend += (sizeof (char *)
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- ((bufferend - (char *) 0)
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% sizeof (char *))) % sizeof (char *);
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/* Now the new address. */
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new_h_addr_list[naddrs++] =
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memcpy (bufferend, tmp_result_buf.h_addr,
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tmp_result_buf.h_length);
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/* Also here a final NULL pointer. */
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new_h_addr_list[naddrs] = NULL;
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/* Store the new array pointers. */
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old_result->h_aliases = new_h_aliases;
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old_result->h_addr_list = new_h_addr_list;
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/* Compute the new buffer end. */
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bufferend = (char *) &new_h_aliases[naliases + 1];
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assert (bufferend <= buffer + buflen);
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result = old_result;
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}
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}
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if (status == NSS_STATUS_TRYAGAIN)
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{
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size_t newsize = 2 * tmp_buflen;
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if (tmp_buffer_malloced)
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{
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char *newp = realloc (tmp_buffer, newsize);
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if (newp != NULL)
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{
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assert ((((uintptr_t) newp)
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& (__alignof__ (struct hostent_data) - 1))
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== 0);
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tmp_buffer = newp;
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tmp_buflen = newsize;
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goto again;
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}
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}
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else if (!__libc_use_alloca (buflen + newsize))
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{
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tmp_buffer = malloc (newsize);
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if (tmp_buffer != NULL)
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{
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assert ((((uintptr_t) tmp_buffer)
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& (__alignof__ (struct hostent_data) - 1))
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== 0);
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tmp_buffer_malloced = true;
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tmp_buflen = newsize;
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goto again;
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}
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}
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else
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{
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tmp_buffer
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= extend_alloca (tmp_buffer, tmp_buflen,
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newsize
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+ __alignof__ (struct hostent_data));
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tmp_buffer = (char *) (((uintptr_t) tmp_buffer
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+ __alignof__ (struct hostent_data)
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- 1)
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& ~(__alignof__ (struct hostent_data)
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- 1));
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goto again;
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}
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}
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else
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status = NSS_STATUS_SUCCESS;
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out:
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if (tmp_buffer_malloced)
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free (tmp_buffer);
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}
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if (! keep_stream)
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internal_endent ();
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}
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if (canonp && status == NSS_STATUS_SUCCESS)
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*canonp = result->h_name;
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__libc_lock_unlock (lock);
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return status;
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}
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enum nss_status
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_nss_files_gethostbyname_r (const char *name, struct hostent *result,
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char *buffer, size_t buflen, int *errnop,
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int *herrnop)
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{
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int af = ((_res.options & RES_USE_INET6) ? AF_INET6 : AF_INET);
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return _nss_files_gethostbyname3_r (name, af, result, buffer, buflen,
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errnop, herrnop, NULL, NULL);
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}
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enum nss_status
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_nss_files_gethostbyname2_r (const char *name, int af, struct hostent *result,
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char *buffer, size_t buflen, int *errnop,
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int *herrnop)
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{
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return _nss_files_gethostbyname3_r (name, af, result, buffer, buflen,
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errnop, herrnop, NULL, NULL);
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}
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enum nss_status
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_nss_files_gethostbyname4_r (const char *name, struct gaih_addrtuple **pat,
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char *buffer, size_t buflen, int *errnop,
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int *herrnop, int32_t *ttlp)
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{
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__libc_lock_lock (lock);
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/* Reset file pointer to beginning or open file. */
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enum nss_status status = internal_setent (keep_stream);
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if (status == NSS_STATUS_SUCCESS)
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{
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/* Tell getent function that we have repositioned the file pointer. */
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last_use = getby;
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bool any = false;
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bool got_canon = false;
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while (1)
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{
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/* Align the buffer for the next record. */
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uintptr_t pad = (-(uintptr_t) buffer
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% __alignof__ (struct hostent_data));
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buffer += pad;
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buflen = buflen > pad ? buflen - pad : 0;
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struct hostent result;
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status = internal_getent (&result, buffer, buflen, errnop,
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herrnop, AF_UNSPEC, 0);
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if (status != NSS_STATUS_SUCCESS)
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break;
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int naliases = 0;
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if (__strcasecmp (name, result.h_name) != 0)
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{
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for (; result.h_aliases[naliases] != NULL; ++naliases)
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if (! __strcasecmp (name, result.h_aliases[naliases]))
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break;
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if (result.h_aliases[naliases] == NULL)
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continue;
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/* We know this alias exist. Count it. */
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++naliases;
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}
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/* Determine how much memory has been used so far. */
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// XXX It is not necessary to preserve the aliases array
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while (result.h_aliases[naliases] != NULL)
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++naliases;
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char *bufferend = (char *) &result.h_aliases[naliases + 1];
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assert (buflen >= bufferend - buffer);
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buflen -= bufferend - buffer;
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buffer = bufferend;
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/* We found something. */
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any = true;
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/* Create the record the caller expects. There is only one
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address. */
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assert (result.h_addr_list[1] == NULL);
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if (*pat == NULL)
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{
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uintptr_t pad = (-(uintptr_t) buffer
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% __alignof__ (struct gaih_addrtuple));
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buffer += pad;
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buflen = buflen > pad ? buflen - pad : 0;
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if (__builtin_expect (buflen < sizeof (struct gaih_addrtuple),
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0))
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{
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*errnop = ERANGE;
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*herrnop = NETDB_INTERNAL;
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status = NSS_STATUS_TRYAGAIN;
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break;
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}
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*pat = (struct gaih_addrtuple *) buffer;
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buffer += sizeof (struct gaih_addrtuple);
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buflen -= sizeof (struct gaih_addrtuple);
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}
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(*pat)->next = NULL;
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(*pat)->name = got_canon ? NULL : result.h_name;
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got_canon = true;
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(*pat)->family = result.h_addrtype;
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memcpy ((*pat)->addr, result.h_addr_list[0], result.h_length);
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(*pat)->scopeid = 0;
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pat = &((*pat)->next);
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/* If we only look for the first matching entry we are done. */
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if ((_res_hconf.flags & HCONF_FLAG_MULTI) == 0)
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break;
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}
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/* If we have to look for multiple records and found one, this
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is a success. */
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if (status == NSS_STATUS_NOTFOUND && any)
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{
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assert ((_res_hconf.flags & HCONF_FLAG_MULTI) != 0);
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status = NSS_STATUS_SUCCESS;
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}
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if (! keep_stream)
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internal_endent ();
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}
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else if (status == NSS_STATUS_TRYAGAIN)
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{
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*errnop = errno;
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*herrnop = TRY_AGAIN;
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}
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else
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{
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*errnop = errno;
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*herrnop = NO_DATA;
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}
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__libc_lock_unlock (lock);
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return status;
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}
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