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298 lines
10 KiB
C
298 lines
10 KiB
C
/* Hosts file parser in nss_files module.
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Copyright (C) 1996-2001, 2003, 2004, 2007
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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, write to the Free
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Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA. */
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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, addr, entdata->host_addr) <= 0
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&& (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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0)))
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/* Illegal address: ignore line. */
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return 0;
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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] = 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 HOST_DB_LOOKUP(name, keysize, keypattern, break_if_match, proto...) \
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enum nss_status \
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_nss_files_get##name##_r (proto, \
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struct STRUCTURE *result, char *buffer, \
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size_t buflen, int *errnop H_ERRNO_PROTO) \
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{ \
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enum nss_status status; \
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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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\
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__libc_lock_lock (lock); \
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\
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/* Reset file pointer to beginning or open file. */ \
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status = internal_setent (keep_stream); \
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\
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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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\
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while ((status = internal_getent (result, buffer, buflen, errnop \
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H_ERRNO_ARG EXTRA_ARGS_VALUE)) \
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== NSS_STATUS_SUCCESS) \
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{ break_if_match } \
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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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const size_t tmp_buflen = MIN (buflen, 4096); \
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char tmp_buffer[tmp_buflen] \
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__attribute__ ((__aligned__ (__alignof__ (struct hostent_data))));\
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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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\
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while (result->h_aliases[naliases] != NULL) \
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++naliases; \
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\
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bufferend = (char *) &result->h_aliases[naliases + 1]; \
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\
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while ((status = internal_getent (&tmp_result_buf, tmp_buffer, \
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tmp_buflen, errnop H_ERRNO_ARG \
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EXTRA_ARGS_VALUE)) \
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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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`break_if_match' value. The optimizer should do its \
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job. */ \
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do \
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{ \
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break_if_match \
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result = old_result; \
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} \
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while ((matches = 0)); \
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\
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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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\
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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 users \
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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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\
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/* Make sure bufferend is aligned. */ \
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assert ((bufferend - (char *) 0) % sizeof (char *) == 0); \
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\
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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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break; \
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} \
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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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\
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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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\
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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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\
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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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\
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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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\
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/* Final NULL pointer. */ \
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new_h_aliases[naliases] = NULL; \
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\
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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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\
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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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\
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/* Also here a final NULL pointer. */ \
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new_h_addr_list[naddrs] = NULL; \
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\
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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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\
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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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\
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result = old_result; \
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} \
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} \
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\
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if (status != NSS_STATUS_TRYAGAIN) \
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status = NSS_STATUS_SUCCESS; \
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} \
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\
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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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\
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__libc_lock_unlock (lock); \
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\
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return status; \
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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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HOST_DB_LOOKUP (hostbyname, ,,
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{
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LOOKUP_NAME_CASE (h_name, h_aliases)
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}, const char *name)
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#undef EXTRA_ARGS_VALUE
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/* XXX Is using _res to determine whether we want to convert IPv4 addresses
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to IPv6 addresses really the right thing to do? */
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#define EXTRA_ARGS_VALUE \
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, af, ((_res.options & RES_USE_INET6) ? AI_V4MAPPED : 0)
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HOST_DB_LOOKUP (hostbyname2, ,,
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{
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LOOKUP_NAME_CASE (h_name, h_aliases)
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}, const char *name, int af)
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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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