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curl/lib/hostares.c
Daniel Stenberg 2d356ba168 ares_query_completed_cb: don't touch invalid data 
When this callback is called due to the destruction of the ares handle,
the connection pointer passed in as an argument may no longer pointing
to valid data and this function doesn't need to do anything with it
anyway so we make sure it doesn't.

Bug: http://curl.haxx.se/mail/lib-2011-01/0333.html
Reported by: Vsevolod Novikov
2011-01-27 14:41:07 +01:00

440 lines
12 KiB
C
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/***************************************************************************
* _ _ ____ _
* Project ___| | | | _ \| |
* / __| | | | |_) | |
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
* Copyright (C) 1998 - 2011, 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_LIMITS_H
#include <limits.h>
#endif
#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
#if (defined(NETWARE) && defined(__NOVELL_LIBC__))
#undef in_addr_t
#define in_addr_t unsigned long
#endif
#include "urldata.h"
#include "sendf.h"
#include "hostip.h"
#include "hash.h"
#include "share.h"
#include "strerror.h"
#include "url.h"
#include "multiif.h"
#include "inet_pton.h"
#include "connect.h"
#include "select.h"
#include "progress.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 ares-enabled builds
**********************************************************************/
#ifdef CURLRES_ARES
/*
* Curl_resolv_fdset() is called when someone from the outside world (using
* curl_multi_fdset()) wants to get our fd_set setup and we're talking with
* ares. The caller must make sure that this function is only called when we
* have a working ares channel.
*
* Returns: CURLE_OK always!
*/
int Curl_resolv_getsock(struct connectdata *conn,
curl_socket_t *socks,
int numsocks)
{
struct timeval maxtime;
struct timeval timebuf;
struct timeval *timeout;
int max = ares_getsock(conn->data->state.areschannel,
(ares_socket_t *)socks, numsocks);
maxtime.tv_sec = CURL_TIMEOUT_RESOLVE;
maxtime.tv_usec = 0;
timeout = ares_timeout(conn->data->state.areschannel, &maxtime, &timebuf);
Curl_expire(conn->data,
(timeout->tv_sec * 1000) + (timeout->tv_usec/1000));
return max;
}
/*
* waitperform()
*
* 1) Ask ares what sockets it currently plays with, then
* 2) wait for the timeout period to check for action on ares' sockets.
* 3) tell ares to act on all the sockets marked as "with action"
*
* return number of sockets it worked on
*/
static int waitperform(struct connectdata *conn, int timeout_ms)
{
struct SessionHandle *data = conn->data;
int nfds;
int bitmask;
ares_socket_t socks[ARES_GETSOCK_MAXNUM];
struct pollfd pfd[ARES_GETSOCK_MAXNUM];
int i;
int num = 0;
bitmask = ares_getsock(data->state.areschannel, socks, ARES_GETSOCK_MAXNUM);
for(i=0; i < ARES_GETSOCK_MAXNUM; i++) {
pfd[i].events = 0;
pfd[i].revents = 0;
if(ARES_GETSOCK_READABLE(bitmask, i)) {
pfd[i].fd = socks[i];
pfd[i].events |= POLLRDNORM|POLLIN;
}
if(ARES_GETSOCK_WRITABLE(bitmask, i)) {
pfd[i].fd = socks[i];
pfd[i].events |= POLLWRNORM|POLLOUT;
}
if(pfd[i].events != 0)
num++;
else
break;
}
if(num)
nfds = Curl_poll(pfd, num, timeout_ms);
else
nfds = 0;
if(!nfds)
/* Call ares_process() unconditonally here, even if we simply timed out
above, as otherwise the ares name resolve won't timeout! */
ares_process_fd(data->state.areschannel, ARES_SOCKET_BAD, ARES_SOCKET_BAD);
else {
/* move through the descriptors and ask for processing on them */
for(i=0; i < num; i++)
ares_process_fd(data->state.areschannel,
pfd[i].revents & (POLLRDNORM|POLLIN)?
pfd[i].fd:ARES_SOCKET_BAD,
pfd[i].revents & (POLLWRNORM|POLLOUT)?
pfd[i].fd:ARES_SOCKET_BAD);
}
return nfds;
}
/*
* Curl_is_resolved() is called repeatedly to check if a previous name resolve
* request has completed. It should also make sure to time-out if the
* operation seems to take too long.
*
* Returns normal CURLcode errors.
*/
CURLcode Curl_is_resolved(struct connectdata *conn,
struct Curl_dns_entry **dns)
{
struct SessionHandle *data = conn->data;
*dns = NULL;
waitperform(conn, 0);
if(conn->async.done) {
/* we're done, kill the ares handle */
if(!conn->async.dns) {
failf(data, "Could not resolve host: %s (%s)", conn->host.dispname,
ares_strerror(conn->async.status));
return CURLE_COULDNT_RESOLVE_HOST;
}
*dns = conn->async.dns;
}
return CURLE_OK;
}
/*
* Curl_wait_for_resolv() waits for a resolve to finish. This function should
* be avoided since using this risk getting the multi interface to "hang".
*
* If 'entry' is non-NULL, make it point to the resolved dns entry
*
* Returns CURLE_COULDNT_RESOLVE_HOST if the host was not resolved, and
* CURLE_OPERATION_TIMEDOUT if a time-out occurred.
*/
CURLcode Curl_wait_for_resolv(struct connectdata *conn,
struct Curl_dns_entry **entry)
{
CURLcode rc=CURLE_OK;
struct SessionHandle *data = conn->data;
long timeout;
struct timeval now = Curl_tvnow();
timeout = Curl_timeleft(data, &now, TRUE);
if(!timeout)
timeout = CURL_TIMEOUT_RESOLVE * 1000; /* default name resolve timeout */
/* Wait for the name resolve query to complete. */
for(;;) {
struct timeval *tvp, tv, store;
long timediff;
int itimeout;
int timeout_ms;
itimeout = (timeout > (long)INT_MAX) ? INT_MAX : (int)timeout;
store.tv_sec = itimeout/1000;
store.tv_usec = (itimeout%1000)*1000;
tvp = ares_timeout(data->state.areschannel, &store, &tv);
/* use the timeout period ares returned to us above if less than one
second is left, otherwise just use 1000ms to make sure the progress
callback gets called frequent enough */
if(!tvp->tv_sec)
timeout_ms = (int)(tvp->tv_usec/1000);
else
timeout_ms = 1000;
waitperform(conn, timeout_ms);
if(conn->async.done)
break;
if(Curl_pgrsUpdate(conn)) {
rc = CURLE_ABORTED_BY_CALLBACK;
timeout = -1; /* trigger the cancel below */
}
else {
struct timeval now2 = Curl_tvnow();
timediff = Curl_tvdiff(now2, now); /* spent time */
timeout -= timediff?timediff:1; /* always deduct at least 1 */
now = now2; /* for next loop */
}
if(timeout < 0) {
/* our timeout, so we cancel the ares operation */
ares_cancel(data->state.areschannel);
break;
}
}
/* Operation complete, if the lookup was successful we now have the entry
in the cache. */
if(entry)
*entry = conn->async.dns;
if(!conn->async.dns) {
/* a name was not resolved */
if((timeout < 0) || (conn->async.status == ARES_ETIMEOUT)) {
if (conn->bits.httpproxy) {
failf(data, "Resolving proxy timed out: %s", conn->proxy.dispname);
rc = CURLE_COULDNT_RESOLVE_PROXY;
}
else {
failf(data, "Resolving host timed out: %s", conn->host.dispname);
rc = CURLE_COULDNT_RESOLVE_HOST;
}
}
else if(conn->async.done) {
if (conn->bits.httpproxy) {
failf(data, "Could not resolve proxy: %s (%s)", conn->proxy.dispname,
ares_strerror(conn->async.status));
rc = CURLE_COULDNT_RESOLVE_PROXY;
}
else {
failf(data, "Could not resolve host: %s (%s)", conn->host.dispname,
ares_strerror(conn->async.status));
rc = CURLE_COULDNT_RESOLVE_HOST;
}
}
else
rc = CURLE_OPERATION_TIMEDOUT;
/* close the connection, since we can't return failure here without
cleaning up this connection properly */
conn->bits.close = TRUE;
}
return rc;
}
/*
* ares_query_completed_cb() is the callback that ares will call when
* the host query initiated by ares_gethostbyname() from Curl_getaddrinfo(),
* when using ares, is completed either successfully or with failure.
*/
static void ares_query_completed_cb(void *arg, /* (struct connectdata *) */
int status,
#ifdef HAVE_CARES_CALLBACK_TIMEOUTS
int timeouts,
#endif
struct hostent *hostent)
{
struct connectdata *conn = (struct connectdata *)arg;
struct Curl_addrinfo * ai = NULL;
#ifdef HAVE_CARES_CALLBACK_TIMEOUTS
(void)timeouts; /* ignored */
#endif
switch(status) {
case CURL_ASYNC_SUCCESS:
ai = Curl_he2ai(hostent, conn->async.port);
break;
case ARES_EDESTRUCTION:
/* this ares handle is getting destroyed, the 'arg' pointer may not be
valid! */
return;
default:
/* do nothing */
break;
}
(void)Curl_addrinfo_callback(arg, status, ai);
}
/*
* Curl_getaddrinfo() - when using ares
*
* Returns name information about the given hostname and port number. If
* successful, the 'hostent' is returned and the forth argument will point to
* memory we need to free after use. That memory *MUST* be freed with
* Curl_freeaddrinfo(), nothing else.
*/
Curl_addrinfo *Curl_getaddrinfo(struct connectdata *conn,
const char *hostname,
int port,
int *waitp)
{
char *bufp;
struct SessionHandle *data = conn->data;
struct in_addr in;
int family = PF_INET;
#ifdef ENABLE_IPV6 /* CURLRES_IPV6 */
struct in6_addr in6;
#endif /* CURLRES_IPV6 */
*waitp = 0; /* default to synchronous response */
/* First check if this is an IPv4 address string */
if(Curl_inet_pton(AF_INET, hostname, &in) > 0) {
/* This is a dotted IP address 123.123.123.123-style */
return Curl_ip2addr(AF_INET, &in, hostname, port);
}
#ifdef ENABLE_IPV6 /* CURLRES_IPV6 */
/* Otherwise, check if this is an IPv6 address string */
if (Curl_inet_pton (AF_INET6, hostname, &in6) > 0) {
/* This must be an IPv6 address literal. */
return Curl_ip2addr(AF_INET6, &in6, hostname, port);
}
switch(conn->ip_version) {
default:
#if ARES_VERSION >= 0x010601
family = PF_UNSPEC; /* supported by c-ares since 1.6.1, so for older
c-ares versions this just falls through and defaults
to PF_INET */
break;
#endif
case CURL_IPRESOLVE_V4:
family = PF_INET;
break;
case CURL_IPRESOLVE_V6:
family = PF_INET6;
break;
}
#endif /* CURLRES_IPV6 */
bufp = strdup(hostname);
if(bufp) {
Curl_safefree(conn->async.hostname);
conn->async.hostname = bufp;
conn->async.port = port;
conn->async.done = FALSE; /* not done */
conn->async.status = 0; /* clear */
conn->async.dns = NULL; /* clear */
conn->async.temp_ai = NULL; /* clear */
#ifdef ENABLE_IPV6 /* CURLRES_IPV6 */
if(family == PF_UNSPEC) {
conn->async.num_pending = 2;
/* areschannel is already setup in the Curl_open() function */
ares_gethostbyname(data->state.areschannel, hostname, PF_INET,
ares_query_completed_cb, conn);
ares_gethostbyname(data->state.areschannel, hostname, PF_INET6,
ares_query_completed_cb, conn);
}
else
#endif /* CURLRES_IPV6 */
{
conn->async.num_pending = 1;
/* areschannel is already setup in the Curl_open() function */
ares_gethostbyname(data->state.areschannel, hostname, family,
ares_query_completed_cb, conn);
}
*waitp = 1; /* expect asynchronous response */
}
return NULL; /* no struct yet */
}
#endif /* CURLRES_ARES */
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