531 строка
14 KiB
C
531 строка
14 KiB
C
/***************************************************************************
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* _ _ ____ _
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* Project ___| | | | _ \| |
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* / __| | | | |_) | |
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* | (__| |_| | _ <| |___
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* \___|\___/|_| \_\_____|
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*
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* Copyright (C) 1998 - 2004, Daniel Stenberg, <daniel@haxx.se>, et al.
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*
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* This software is licensed as described in the file COPYING, which
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* you should have received as part of this distribution. The terms
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* are also available at http://curl.haxx.se/docs/copyright.html.
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*
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* You may opt to use, copy, modify, merge, publish, distribute and/or sell
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* copies of the Software, and permit persons to whom the Software is
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* furnished to do so, under the terms of the COPYING file.
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*
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* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
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* KIND, either express or implied.
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*
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* $Id$
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***************************************************************************/
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#include "setup.h"
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#include <string.h>
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#include <errno.h>
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#define _REENTRANT
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#if defined(WIN32) && !defined(__GNUC__) || defined(__MINGW32__)
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#include <malloc.h>
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#else
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#ifdef HAVE_SYS_TYPES_H
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#include <sys/types.h>
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#endif
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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_STDLIB_H
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#include <stdlib.h> /* required for free() prototypes */
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#endif
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#ifdef HAVE_UNISTD_H
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#include <unistd.h> /* for the close() proto */
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#endif
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#ifdef VMS
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#include <in.h>
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#include <inet.h>
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#include <stdlib.h>
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#endif
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#endif
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#ifdef HAVE_SETJMP_H
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#include <setjmp.h>
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#endif
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#ifdef WIN32
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#include <process.h>
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#endif
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#if (defined(NETWARE) && defined(__NOVELL_LIBC__))
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#undef in_addr_t
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#define in_addr_t unsigned long
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#endif
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#include "urldata.h"
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#include "sendf.h"
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#include "hostip.h"
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#include "hash.h"
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#include "share.h"
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#include "strerror.h"
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#include "url.h"
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#include "inet_ntop.h"
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#define _MPRINTF_REPLACE /* use our functions only */
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#include <curl/mprintf.h>
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#if defined(HAVE_INET_NTOA_R) && !defined(HAVE_INET_NTOA_R_DECL)
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#include "inet_ntoa_r.h"
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#endif
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#include "memory.h"
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/* The last #include file should be: */
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#include "memdebug.h"
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/*
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* hostip.c explained
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* ==================
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*
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* The main COMPILE-TIME DEFINES to keep in mind when reading the host*.c
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* source file are these:
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*
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* CURLRES_IPV6 - this host has getaddrinfo() and family, and thus we use
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* that. The host may not be able to resolve IPv6, but we don't really have to
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* take that into account. Hosts that aren't IPv6-enabled have CURLRES_IPV4
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* defined.
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*
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* CURLRES_ARES - is defined if libcurl is built to use c-ares for
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* asynchronous name resolves. It cannot have ENABLE_IPV6 defined at the same
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* time, as c-ares has no ipv6 support. This can be Windows or *nix.
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*
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* CURLRES_THREADED - is defined if libcurl is built to run under (native)
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* Windows, and then the name resolve will be done in a new thread, and the
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* supported API will be the same as for ares-builds.
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*
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* If any of the two previous are defined, CURLRES_ASYNCH is defined too. If
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* libcurl is not built to use an asynchronous resolver, CURLRES_SYNCH is
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* defined.
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*
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* The host*.c sources files are split up like this:
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*
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* hostip.c - method-independent resolver functions and utility functions
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* hostasyn.c - functions for asynchronous name resolves
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* hostsyn.c - functions for synchronous name resolves
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* hostares.c - functions for ares-using name resolves
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* hostthre.c - functions for threaded name resolves
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* hostip4.c - ipv4-specific functions
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* hostip6.c - ipv6-specific functions
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*
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* The hostip.h is the united header file for all this. It defines the
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* CURLRES_* defines based on the config*.h and setup.h defines.
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*/
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/* These two symbols are for the global DNS cache */
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static curl_hash hostname_cache;
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static int host_cache_initialized;
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static void freednsentry(void *freethis);
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/*
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* Curl_global_host_cache_init() initializes and sets up a global DNS cache.
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* Global DNS cache is general badness. Do not use. This will be removed in
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* a future version. Use the share interface instead!
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*/
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void Curl_global_host_cache_init(void)
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{
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if (!host_cache_initialized) {
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Curl_hash_init(&hostname_cache, 7, freednsentry);
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host_cache_initialized = 1;
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}
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}
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/*
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* Return a pointer to the global cache
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*/
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curl_hash *Curl_global_host_cache_get(void)
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{
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return &hostname_cache;
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}
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/*
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* Destroy and cleanup the global DNS cache
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*/
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void Curl_global_host_cache_dtor(void)
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{
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if (host_cache_initialized) {
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Curl_hash_clean(&hostname_cache);
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host_cache_initialized = 0;
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}
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}
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/*
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* Return # of adresses in a Curl_addrinfo struct
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*/
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int Curl_num_addresses(const Curl_addrinfo *addr)
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{
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int i;
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for (i = 0; addr; addr = addr->ai_next, i++);
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return i;
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}
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/*
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* Curl_printable_address() returns a printable version of the 1st address
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* given in the 'ip' argument. The result will be stored in the buf that is
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* bufsize bytes big.
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*
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* If the conversion fails, it returns NULL.
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*/
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const char *Curl_printable_address(const Curl_addrinfo *ip,
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char *buf, size_t bufsize)
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{
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const void *ip4 = &((const struct sockaddr_in*)ip->ai_addr)->sin_addr;
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int af = ip->ai_family;
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#ifdef CURLRES_IPV6
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const void *ip6 = &((const struct sockaddr_in6*)ip->ai_addr)->sin6_addr;
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#else
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const void *ip6 = NULL;
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#endif
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return Curl_inet_ntop(af, af == AF_INET ? ip4 : ip6, buf, bufsize);
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}
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/*
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* Return a hostcache id string for the providing host + port, to be used by
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* the DNS caching.
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*/
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static char *
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create_hostcache_id(char *server, int port)
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{
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/* create and return the new allocated entry */
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return aprintf("%s:%d", server, port);
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}
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struct hostcache_prune_data {
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int cache_timeout;
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time_t now;
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};
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/*
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* This function is set as a callback to be called for every entry in the DNS
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* cache when we want to prune old unused entries.
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*
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* Returning non-zero means remove the entry, return 0 to keep it in the
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* cache.
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*/
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static int
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hostcache_timestamp_remove(void *datap, void *hc)
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{
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struct hostcache_prune_data *data =
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(struct hostcache_prune_data *) datap;
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struct Curl_dns_entry *c = (struct Curl_dns_entry *) hc;
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if ((data->now - c->timestamp < data->cache_timeout) ||
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c->inuse) {
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/* please don't remove */
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return 0;
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}
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/* fine, remove */
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return 1;
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}
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/*
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* Prune the DNS cache. This assumes that a lock has already been taken.
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*/
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static void
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hostcache_prune(curl_hash *hostcache, int cache_timeout, time_t now)
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{
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struct hostcache_prune_data user;
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user.cache_timeout = cache_timeout;
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user.now = now;
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Curl_hash_clean_with_criterium(hostcache,
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(void *) &user,
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hostcache_timestamp_remove);
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}
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/*
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* Library-wide function for pruning the DNS cache. This function takes and
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* returns the appropriate locks.
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*/
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void Curl_hostcache_prune(struct SessionHandle *data)
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{
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time_t now;
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if((data->set.dns_cache_timeout == -1) || !data->hostcache)
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/* cache forever means never prune, and NULL hostcache means
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we can't do it */
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return;
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if(data->share)
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Curl_share_lock(data, CURL_LOCK_DATA_DNS, CURL_LOCK_ACCESS_SINGLE);
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time(&now);
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/* Remove outdated and unused entries from the hostcache */
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hostcache_prune(data->hostcache,
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data->set.dns_cache_timeout,
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now);
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if(data->share)
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Curl_share_unlock(data, CURL_LOCK_DATA_DNS);
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}
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#ifdef HAVE_SIGSETJMP
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/* Beware this is a global and unique instance. This is used to store the
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return address that we can jump back to from inside a signal handler. This
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is not thread-safe stuff. */
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sigjmp_buf curl_jmpenv;
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#endif
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/*
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* Curl_cache_addr() stores a 'Curl_addrinfo' struct in the DNS cache.
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*
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* When calling Curl_resolv() has resulted in a response with a returned
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* address, we call this function to store the information in the dns
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* cache etc
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*
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* Returns the Curl_dns_entry entry pointer or NULL if the storage failed.
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*/
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struct Curl_dns_entry *
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Curl_cache_addr(struct SessionHandle *data,
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Curl_addrinfo *addr,
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char *hostname,
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int port)
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{
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char *entry_id;
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size_t entry_len;
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struct Curl_dns_entry *dns;
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struct Curl_dns_entry *dns2;
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time_t now;
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/* Create an entry id, based upon the hostname and port */
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entry_id = create_hostcache_id(hostname, port);
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/* If we can't create the entry id, fail */
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if (!entry_id)
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return NULL;
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entry_len = strlen(entry_id);
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/* Create a new cache entry */
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dns = (struct Curl_dns_entry *) malloc(sizeof(struct Curl_dns_entry));
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if (!dns) {
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free(entry_id);
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return NULL;
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}
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dns->inuse = 0; /* init to not used */
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dns->addr = addr; /* this is the address(es) */
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/* Store the resolved data in our DNS cache. This function may return a
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pointer to an existing struct already present in the hash, and it may
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return the same argument we pass in. Make no assumptions. */
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dns2 = Curl_hash_add(data->hostcache, entry_id, entry_len+1, (void *)dns);
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if(!dns2) {
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/* Major badness, run away. */
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free(dns);
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free(entry_id);
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return NULL;
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}
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time(&now);
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dns = dns2;
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dns->timestamp = now; /* used now */
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dns->inuse++; /* mark entry as in-use */
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/* free the allocated entry_id again */
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free(entry_id);
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return dns;
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}
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/*
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* Curl_resolv() is the main name resolve function within libcurl. It resolves
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* a name and returns a pointer to the entry in the 'entry' argument (if one
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* is provided). This function might return immediately if we're using asynch
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* resolves. See the return codes.
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*
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* The cache entry we return will get its 'inuse' counter increased when this
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* function is used. You MUST call Curl_resolv_unlock() later (when you're
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* done using this struct) to decrease the counter again.
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*
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* Return codes:
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*
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* CURLRESOLV_ERROR (-1) = error, no pointer
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* CURLRESOLV_RESOLVED (0) = OK, pointer provided
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* CURLRESOLV_PENDING (1) = waiting for response, no pointer
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*/
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int Curl_resolv(struct connectdata *conn,
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char *hostname,
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int port,
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struct Curl_dns_entry **entry)
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{
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char *entry_id = NULL;
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struct Curl_dns_entry *dns = NULL;
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size_t entry_len;
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int wait;
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struct SessionHandle *data = conn->data;
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CURLcode result;
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int rc;
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*entry = NULL;
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#ifdef HAVE_SIGSETJMP
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/* this allows us to time-out from the name resolver, as the timeout
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will generate a signal and we will siglongjmp() from that here */
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if(!data->set.no_signal && sigsetjmp(curl_jmpenv, 1)) {
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/* this is coming from a siglongjmp() */
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failf(data, "name lookup timed out");
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return CURLRESOLV_ERROR;
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}
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#endif
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/* Create an entry id, based upon the hostname and port */
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entry_id = create_hostcache_id(hostname, port);
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/* If we can't create the entry id, fail */
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if (!entry_id)
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return CURLRESOLV_ERROR;
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entry_len = strlen(entry_id);
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if(data->share)
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Curl_share_lock(data, CURL_LOCK_DATA_DNS, CURL_LOCK_ACCESS_SINGLE);
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/* See if its already in our dns cache */
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dns = Curl_hash_pick(data->hostcache, entry_id, entry_len+1);
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if(data->share)
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Curl_share_unlock(data, CURL_LOCK_DATA_DNS);
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/* free the allocated entry_id again */
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free(entry_id);
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rc = CURLRESOLV_ERROR; /* default to failure */
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if (!dns) {
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/* The entry was not in the cache. Resolve it to IP address */
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Curl_addrinfo *addr;
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/* Check what IP specifics the app has requested and if we can provide it.
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* If not, bail out. */
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if(!Curl_ipvalid(data))
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return CURLRESOLV_ERROR;
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/* If Curl_getaddrinfo() returns NULL, 'wait' might be set to a non-zero
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value indicating that we need to wait for the response to the resolve
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call */
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addr = Curl_getaddrinfo(conn, hostname, port, &wait);
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if (!addr) {
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if(wait) {
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/* the response to our resolve call will come asynchronously at
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a later time, good or bad */
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/* First, check that we haven't received the info by now */
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result = Curl_is_resolved(conn, &dns);
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if(result) /* error detected */
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return CURLRESOLV_ERROR;
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if(dns)
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rc = CURLRESOLV_RESOLVED; /* pointer provided */
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else
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rc = CURLRESOLV_PENDING; /* no info yet */
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}
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}
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else {
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if(data->share)
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Curl_share_lock(data, CURL_LOCK_DATA_DNS, CURL_LOCK_ACCESS_SINGLE);
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/* we got a response, store it in the cache */
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dns = Curl_cache_addr(data, addr, hostname, port);
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if(data->share)
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Curl_share_unlock(data, CURL_LOCK_DATA_DNS);
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if(!dns)
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/* returned failure, bail out nicely */
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Curl_freeaddrinfo(addr);
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else
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rc = CURLRESOLV_RESOLVED;
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}
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}
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else {
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if(data->share)
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Curl_share_lock(data, CURL_LOCK_DATA_DNS, CURL_LOCK_ACCESS_SINGLE);
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dns->inuse++; /* we use it! */
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if(data->share)
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Curl_share_unlock(data, CURL_LOCK_DATA_DNS);
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rc = CURLRESOLV_RESOLVED;
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}
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*entry = dns;
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return rc;
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}
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/*
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* Curl_resolv_unlock() unlocks the given cached DNS entry. When this has been
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* made, the struct may be destroyed due to pruning. It is important that only
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* one unlock is made for each Curl_resolv() call.
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*/
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void Curl_resolv_unlock(struct SessionHandle *data, struct Curl_dns_entry *dns)
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{
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curlassert(dns && (dns->inuse>0));
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if(data->share)
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Curl_share_lock(data, CURL_LOCK_DATA_DNS, CURL_LOCK_ACCESS_SINGLE);
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dns->inuse--;
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if(data->share)
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Curl_share_unlock(data, CURL_LOCK_DATA_DNS);
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}
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/*
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* File-internal: free a cache dns entry.
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*/
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static void freednsentry(void *freethis)
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{
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struct Curl_dns_entry *p = (struct Curl_dns_entry *) freethis;
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Curl_freeaddrinfo(p->addr);
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free(p);
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}
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/*
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* Curl_mk_dnscache() creates a new DNS cache and returns the handle for it.
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*/
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curl_hash *Curl_mk_dnscache(void)
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{
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return Curl_hash_alloc(7, freednsentry);
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}
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#ifdef CURLRES_ADDRINFO_COPY
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/* align on even 64bit boundaries */
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#define MEMALIGN(x) ((x)+(8-(((unsigned long)(x))&0x7)))
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/*
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* Curl_addrinfo_copy() performs a "deep" copy of a hostent into a buffer and
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* returns a pointer to the malloc()ed copy. You need to call free() on the
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* returned buffer when you're done with it.
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*/
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Curl_addrinfo *Curl_addrinfo_copy(void *org, int port)
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{
|
|
struct hostent *orig = org;
|
|
|
|
return Curl_he2ai(orig, port);
|
|
}
|
|
#endif /* CURLRES_ADDRINFO_COPY */
|