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curl/lib/hostasyn.c
Daniel Stenberg b6a3e2be8e c-ares: fix cancelled resolves
When built IPv6-enabled, we could do Curl_done() with one of the two
resolves having returned already, so when ares_cancel() is called the
resolve callback ends up doing funny things (sometimes resulting in a
segfault) since it would try to actually store the previous resolve even
though we're shutting down the resolve.

This bug was introduced in commit 8ab137b2bc so it hasn't been
included in any public release.

Bug: http://curl.haxx.se/bug/view.cgi?id=3145445
Reported by: Pedro Larroy
2010-12-27 10:01:44 +01:00

201 lines
5.8 KiB
C

/***************************************************************************
* _ _ ____ _
* Project ___| | | | _ \| |
* / __| | | | |_) | |
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
* Copyright (C) 1998 - 2010, Daniel Stenberg, <daniel@haxx.se>, et al.
*
* This software is licensed as described in the file COPYING, which
* you should have received as part of this distribution. The terms
* are also available at http://curl.haxx.se/docs/copyright.html.
*
* You may opt to use, copy, modify, merge, publish, distribute and/or sell
* copies of the Software, and permit persons to whom the Software is
* furnished to do so, under the terms of the COPYING file.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
***************************************************************************/
#include "setup.h"
#include <string.h>
#ifdef HAVE_SYS_SOCKET_H
#include <sys/socket.h>
#endif
#ifdef HAVE_NETINET_IN_H
#include <netinet/in.h>
#endif
#ifdef HAVE_NETDB_H
#include <netdb.h>
#endif
#ifdef HAVE_ARPA_INET_H
#include <arpa/inet.h>
#endif
#ifdef HAVE_STDLIB_H
#include <stdlib.h> /* required for free() prototypes */
#endif
#ifdef HAVE_UNISTD_H
#include <unistd.h> /* for the close() proto */
#endif
#ifdef __VMS
#include <in.h>
#include <inet.h>
#include <stdlib.h>
#endif
#ifdef HAVE_PROCESS_H
#include <process.h>
#endif
#include "urldata.h"
#include "sendf.h"
#include "hostip.h"
#include "hash.h"
#include "share.h"
#include "strerror.h"
#include "url.h"
#define _MPRINTF_REPLACE /* use our functions only */
#include <curl/mprintf.h>
#include "curl_memory.h"
/* The last #include file should be: */
#include "memdebug.h"
/***********************************************************************
* Only for builds using asynchronous name resolves
**********************************************************************/
#ifdef CURLRES_ASYNCH
/*
* Cancel all possibly still on-going resolves for this connection.
*/
void Curl_async_cancel(struct connectdata *conn)
{
/* If we have a "half" response already received, we first clear that off
so that nothing is tempted to use it */
if(conn->async.temp_ai) {
Curl_freeaddrinfo(conn->async.temp_ai);
conn->async.temp_ai = NULL;
}
/* for ares-using, make sure all possible outstanding requests are properly
cancelled before we proceed */
ares_cancel(conn->data->state.areschannel);
}
/*
* Curl_addrinfo_callback() gets called by ares, gethostbyname_thread()
* or getaddrinfo_thread() when we got the name resolved (or not!).
*
* If the status argument is CURL_ASYNC_SUCCESS, this function takes
* ownership of the Curl_addrinfo passed, storing the resolved data
* in the DNS cache.
*
* The storage operation locks and unlocks the DNS cache.
*/
CURLcode Curl_addrinfo_callback(struct connectdata *conn,
int status,
struct Curl_addrinfo *ai)
{
struct Curl_dns_entry *dns = NULL;
CURLcode rc = CURLE_OK;
conn->async.status = status;
if(CURL_ASYNC_SUCCESS == status) {
if(ai) {
struct SessionHandle *data = conn->data;
#if defined(ENABLE_IPV6) && defined(CURLRES_ARES) /* CURLRES_IPV6 */
Curl_addrinfo *ai_tail = ai;
while (ai_tail->ai_next)
ai_tail = ai_tail->ai_next;
/* Add the new results to the list of old results. */
ai_tail->ai_next = conn->async.temp_ai;
conn->async.temp_ai = ai;
if(--conn->async.num_pending > 0)
/* We are not done yet. Just return. */
return CURLE_OK;
#endif
if(data->share)
Curl_share_lock(data, CURL_LOCK_DATA_DNS, CURL_LOCK_ACCESS_SINGLE);
dns = Curl_cache_addr(data, ai,
conn->async.hostname,
conn->async.port);
if(!dns) {
/* failed to store, cleanup and return error */
Curl_freeaddrinfo(ai);
rc = CURLE_OUT_OF_MEMORY;
}
if(data->share)
Curl_share_unlock(data, CURL_LOCK_DATA_DNS);
}
else {
#if defined(ENABLE_IPV6) && defined(CURLRES_ARES) /* CURLRES_IPV6 */
if(--conn->async.num_pending > 0) {
/* We are not done yet. Clean up and return.
This function will be called again. */
if(conn->async.temp_ai)
Curl_freeaddrinfo(conn->async.temp_ai);
return CURLE_OUT_OF_MEMORY;
}
#endif
rc = CURLE_OUT_OF_MEMORY;
}
}
#if defined(ENABLE_IPV6) && defined(CURLRES_ARES) /* CURLRES_IPV6 */
else
{
if(--conn->async.num_pending > 0)
/* We are not done yet. Just return. */
return CURLE_OK;
if(conn->async.temp_ai) {
/* We are done, and while this latest request
failed, some previous results exist. */
struct SessionHandle *data = conn->data;
if(data->share)
Curl_share_lock(data, CURL_LOCK_DATA_DNS, CURL_LOCK_ACCESS_SINGLE);
dns = Curl_cache_addr(data, conn->async.temp_ai,
conn->async.hostname,
conn->async.port);
if(!dns) {
/* failed to store, cleanup and return error */
Curl_freeaddrinfo(conn->async.temp_ai);
rc = CURLE_OUT_OF_MEMORY;
}
if(data->share)
Curl_share_unlock(data, CURL_LOCK_DATA_DNS);
}
}
#endif
conn->async.dns = dns;
/* Set async.done TRUE last in this function since it may be used multi-
threaded and once this is TRUE the other thread may read fields from the
async struct */
conn->async.done = TRUE;
/* ipv4: The input hostent struct will be freed by ares when we return from
this function */
return rc;
}
#endif /* CURLRES_ASYNCH */