285 строки
8.1 KiB
C
285 строки
8.1 KiB
C
/* $Id$ */
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/* Copyright 1998 by the Massachusetts Institute of Technology.
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*
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* Permission to use, copy, modify, and distribute this
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* software and its documentation for any purpose and without
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* fee is hereby granted, provided that the above copyright
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* notice appear in all copies and that both that copyright
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* notice and this permission notice appear in supporting
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* documentation, and that the name of M.I.T. not be used in
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* advertising or publicity pertaining to distribution of the
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* software without specific, written prior permission.
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* M.I.T. makes no representations about the suitability of
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* this software for any purpose. It is provided "as is"
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* without express or implied warranty.
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*/
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#include "setup.h"
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#ifdef HAVE_SYS_SOCKET_H
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# include <sys/socket.h>
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#endif
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#ifdef HAVE_NETINET_IN_H
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# include <netinet/in.h>
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#endif
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#ifdef HAVE_NETDB_H
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# include <netdb.h>
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#endif
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#ifdef HAVE_ARPA_INET_H
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# include <arpa/inet.h>
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#endif
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#ifdef HAVE_ARPA_NAMESER_H
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# include <arpa/nameser.h>
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#else
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# include "nameser.h"
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#endif
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#ifdef HAVE_ARPA_NAMESER_COMPAT_H
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# include <arpa/nameser_compat.h>
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#endif
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include "ares.h"
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#include "inet_net_pton.h"
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#include "ares_private.h"
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#ifdef WATT32
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#undef WIN32
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#endif
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struct addr_query {
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/* Arguments passed to ares_gethostbyaddr() */
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ares_channel channel;
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struct ares_addr addr;
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ares_host_callback callback;
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void *arg;
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const char *remaining_lookups;
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int timeouts;
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};
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static void next_lookup(struct addr_query *aquery);
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static void addr_callback(void *arg, int status, int timeouts,
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unsigned char *abuf, int alen);
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static void end_aquery(struct addr_query *aquery, int status,
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struct hostent *host);
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static int file_lookup(struct ares_addr *addr, struct hostent **host);
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static void ptr_rr_name(char *name, const struct ares_addr *addr);
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void ares_gethostbyaddr(ares_channel channel, const void *addr, int addrlen,
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int family, ares_host_callback callback, void *arg)
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{
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struct addr_query *aquery;
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if (family != AF_INET && family != AF_INET6)
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{
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callback(arg, ARES_ENOTIMP, 0, NULL);
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return;
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}
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if ((family == AF_INET && addrlen != sizeof(struct in_addr)) ||
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(family == AF_INET6 && addrlen != sizeof(struct in6_addr)))
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{
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callback(arg, ARES_ENOTIMP, 0, NULL);
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return;
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}
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aquery = malloc(sizeof(struct addr_query));
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if (!aquery)
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{
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callback(arg, ARES_ENOMEM, 0, NULL);
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return;
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}
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aquery->channel = channel;
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if (family == AF_INET)
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memcpy(&aquery->addr.addrV4, addr, sizeof(struct in_addr));
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else
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memcpy(&aquery->addr.addrV6, addr, sizeof(struct in6_addr));
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aquery->addr.family = family;
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aquery->callback = callback;
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aquery->arg = arg;
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aquery->remaining_lookups = channel->lookups;
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aquery->timeouts = 0;
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next_lookup(aquery);
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}
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static void next_lookup(struct addr_query *aquery)
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{
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const char *p;
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char name[128];
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int status;
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struct hostent *host;
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for (p = aquery->remaining_lookups; *p; p++)
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{
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switch (*p)
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{
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case 'b':
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ptr_rr_name(name, &aquery->addr);
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aquery->remaining_lookups = p + 1;
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ares_query(aquery->channel, name, C_IN, T_PTR, addr_callback,
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aquery);
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return;
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case 'f':
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status = file_lookup(&aquery->addr, &host);
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/* this status check below previously checked for !ARES_ENOTFOUND,
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but we should not assume that this single error code is the one
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that can occur, as that is in fact no longer the case */
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if (status == ARES_SUCCESS)
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{
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end_aquery(aquery, status, host);
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return;
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}
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break;
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}
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}
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end_aquery(aquery, ARES_ENOTFOUND, NULL);
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}
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static void addr_callback(void *arg, int status, int timeouts,
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unsigned char *abuf, int alen)
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{
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struct addr_query *aquery = (struct addr_query *) arg;
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struct hostent *host;
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aquery->timeouts += timeouts;
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if (status == ARES_SUCCESS)
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{
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if (aquery->addr.family == AF_INET)
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status = ares_parse_ptr_reply(abuf, alen, &aquery->addr.addrV4,
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sizeof(struct in_addr), AF_INET, &host);
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else
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status = ares_parse_ptr_reply(abuf, alen, &aquery->addr.addrV6,
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sizeof(struct in6_addr), AF_INET6, &host);
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end_aquery(aquery, status, host);
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}
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else if (status == ARES_EDESTRUCTION)
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end_aquery(aquery, status, NULL);
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else
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next_lookup(aquery);
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}
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static void end_aquery(struct addr_query *aquery, int status,
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struct hostent *host)
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{
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aquery->callback(aquery->arg, status, aquery->timeouts, host);
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if (host)
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ares_free_hostent(host);
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free(aquery);
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}
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static int file_lookup(struct ares_addr *addr, struct hostent **host)
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{
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FILE *fp;
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int status;
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int error;
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#ifdef WIN32
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char PATH_HOSTS[MAX_PATH];
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if (IS_NT()) {
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char tmp[MAX_PATH];
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HKEY hkeyHosts;
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if (RegOpenKeyEx(HKEY_LOCAL_MACHINE, WIN_NS_NT_KEY, 0, KEY_READ, &hkeyHosts)
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== ERROR_SUCCESS)
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{
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DWORD dwLength = MAX_PATH;
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RegQueryValueEx(hkeyHosts, DATABASEPATH, NULL, NULL, (LPBYTE)tmp,
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&dwLength);
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ExpandEnvironmentStrings(tmp, PATH_HOSTS, MAX_PATH);
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RegCloseKey(hkeyHosts);
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}
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}
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else
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GetWindowsDirectory(PATH_HOSTS, MAX_PATH);
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strcat(PATH_HOSTS, WIN_PATH_HOSTS);
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#elif defined(WATT32)
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extern const char *_w32_GetHostsFile (void);
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const char *PATH_HOSTS = _w32_GetHostsFile();
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if (!PATH_HOSTS)
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return ARES_ENOTFOUND;
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#endif
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fp = fopen(PATH_HOSTS, "r");
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if (!fp)
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{
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error = ERRNO;
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switch(error)
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{
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case ENOENT:
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case ESRCH:
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return ARES_ENOTFOUND;
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default:
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DEBUGF(fprintf(stderr, "fopen() failed with error: %d %s\n",
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error, strerror(error)));
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DEBUGF(fprintf(stderr, "Error opening file: %s\n",
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PATH_HOSTS));
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*host = NULL;
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return ARES_EFILE;
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}
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}
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while ((status = ares__get_hostent(fp, addr->family, host)) == ARES_SUCCESS)
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{
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if (addr->family != (*host)->h_addrtype)
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{
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ares_free_hostent(*host);
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continue;
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}
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if (addr->family == AF_INET)
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{
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if (memcmp((*host)->h_addr, &addr->addrV4, sizeof(struct in_addr)) == 0)
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break;
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}
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else if (addr->family == AF_INET6)
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{
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if (memcmp((*host)->h_addr, &addr->addrV6, sizeof(struct in6_addr)) == 0)
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break;
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}
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ares_free_hostent(*host);
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}
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fclose(fp);
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if (status == ARES_EOF)
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status = ARES_ENOTFOUND;
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if (status != ARES_SUCCESS)
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*host = NULL;
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return status;
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}
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static void ptr_rr_name(char *name, const struct ares_addr *addr)
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{
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if (addr->family == AF_INET)
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{
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unsigned long laddr = ntohl(addr->addrV4.s_addr);
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int a1 = (int)((laddr >> 24) & 0xff);
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int a2 = (int)((laddr >> 16) & 0xff);
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int a3 = (int)((laddr >> 8) & 0xff);
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int a4 = (int)(laddr & 0xff);
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sprintf(name, "%d.%d.%d.%d.in-addr.arpa", a4, a3, a2, a1);
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}
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else
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{
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unsigned char *bytes = (unsigned char *)&addr->addrV6.s6_addr;
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/* There are too many arguments to do this in one line using
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* minimally C89-compliant compilers */
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sprintf(name,
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"%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.",
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bytes[15]&0xf, bytes[15] >> 4, bytes[14]&0xf, bytes[14] >> 4,
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bytes[13]&0xf, bytes[13] >> 4, bytes[12]&0xf, bytes[12] >> 4,
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bytes[11]&0xf, bytes[11] >> 4, bytes[10]&0xf, bytes[10] >> 4,
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bytes[9]&0xf, bytes[9] >> 4, bytes[8]&0xf, bytes[8] >> 4);
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sprintf(name+strlen(name),
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"%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.ip6.arpa",
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bytes[7]&0xf, bytes[7] >> 4, bytes[6]&0xf, bytes[6] >> 4,
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bytes[5]&0xf, bytes[5] >> 4, bytes[4]&0xf, bytes[4] >> 4,
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bytes[3]&0xf, bytes[3] >> 4, bytes[2]&0xf, bytes[2] >> 4,
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bytes[1]&0xf, bytes[1] >> 4, bytes[0]&0xf, bytes[0] >> 4);
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}
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}
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