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curl/lib/asyn-thread.c
Pavel P 428579f5d1 asyn-thread: fix curl_global_cleanup crash in Windows 
- Make sure that asynchronous resolves handled by Winsock are stopped
  before WSACleanup is called.

This is implemented by ensuring that when Curl_resolver_kill is called
(eg via multi_done) it will cancel the Winsock asynchronous resolve and
wait for the cancellation to complete. Winsock runs the asynchronous
completion routine immediately when a resolve is canceled.

Prior to this change it was possible that during curl_global_cleanup
"a DNS resolver thread created by GetAddrInfoExW did not terminate yet,
however curl is already shutting down, deinitializing Winsock with
WSACleanup() leading to an access violation."

Background:

If libcurl is built with the asynchronous threaded resolver option for
Windows then it resolves in one of two ways. For Windows 8.1 and later,
libcurl resolves by using the Winsock asynchronous resolver which does
its own thread management. For older versions of Windows, libcurl
resolves by creating a separate thread that calls getaddrinfo. This
change only affects the former and it's already handled for the latter.

Reported-by: Ch40zz@users.noreply.github.com

Fixes https://github.com/curl/curl/issues/13509
Closes https://github.com/curl/curl/pull/13518
2024-05-07 14:54:11 -04:00

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/***************************************************************************
* _ _ ____ _
* Project ___| | | | _ \| |
* / __| | | | |_) | |
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
* Copyright (C) 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 https://curl.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.
*
* SPDX-License-Identifier: curl
*
***************************************************************************/
#include "curl_setup.h"
#include "socketpair.h"
/***********************************************************************
* Only for threaded name resolves builds
**********************************************************************/
#ifdef CURLRES_THREADED
#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 __VMS
#include <in.h>
#include <inet.h>
#endif
#if defined(USE_THREADS_POSIX) && defined(HAVE_PTHREAD_H)
# include <pthread.h>
#endif
#ifdef HAVE_GETADDRINFO
# define RESOLVER_ENOMEM EAI_MEMORY
#else
# define RESOLVER_ENOMEM ENOMEM
#endif
#include "system_win32.h"
#include "urldata.h"
#include "sendf.h"
#include "hostip.h"
#include "hash.h"
#include "share.h"
#include "url.h"
#include "multiif.h"
#include "inet_ntop.h"
#include "curl_threads.h"
#include "connect.h"
/* The last 3 #include files should be in this order */
#include "curl_printf.h"
#include "curl_memory.h"
#include "memdebug.h"
struct resdata {
struct curltime start;
};
/*
* Curl_resolver_global_init()
* Called from curl_global_init() to initialize global resolver environment.
* Does nothing here.
*/
int Curl_resolver_global_init(void)
{
return CURLE_OK;
}
/*
* Curl_resolver_global_cleanup()
* Called from curl_global_cleanup() to destroy global resolver environment.
* Does nothing here.
*/
void Curl_resolver_global_cleanup(void)
{
}
/*
* Curl_resolver_init()
* Called from curl_easy_init() -> Curl_open() to initialize resolver
* URL-state specific environment ('resolver' member of the UrlState
* structure).
*/
CURLcode Curl_resolver_init(struct Curl_easy *easy, void **resolver)
{
(void)easy;
*resolver = calloc(1, sizeof(struct resdata));
if(!*resolver)
return CURLE_OUT_OF_MEMORY;
return CURLE_OK;
}
/*
* Curl_resolver_cleanup()
* Called from curl_easy_cleanup() -> Curl_close() to cleanup resolver
* URL-state specific environment ('resolver' member of the UrlState
* structure).
*/
void Curl_resolver_cleanup(void *resolver)
{
free(resolver);
}
/*
* Curl_resolver_duphandle()
* Called from curl_easy_duphandle() to duplicate resolver URL state-specific
* environment ('resolver' member of the UrlState structure).
*/
CURLcode Curl_resolver_duphandle(struct Curl_easy *easy, void **to, void *from)
{
(void)from;
return Curl_resolver_init(easy, to);
}
static void destroy_async_data(struct Curl_async *);
/*
* Cancel all possibly still on-going resolves for this connection.
*/
void Curl_resolver_cancel(struct Curl_easy *data)
{
destroy_async_data(&data->state.async);
}
/* This function is used to init a threaded resolve */
static bool init_resolve_thread(struct Curl_easy *data,
const char *hostname, int port,
const struct addrinfo *hints);
#ifdef _WIN32
/* Thread sync data used by GetAddrInfoExW for win8+ */
struct thread_sync_data_w8
{
OVERLAPPED overlapped;
ADDRINFOEXW_ *res;
HANDLE cancel_ev;
ADDRINFOEXW_ hints;
};
#endif
/* Data for synchronization between resolver thread and its parent */
struct thread_sync_data {
#ifdef _WIN32
struct thread_sync_data_w8 w8;
#endif
curl_mutex_t *mtx;
int done;
int port;
char *hostname; /* hostname to resolve, Curl_async.hostname
duplicate */
#ifndef CURL_DISABLE_SOCKETPAIR
struct Curl_easy *data;
curl_socket_t sock_pair[2]; /* socket pair */
#endif
int sock_error;
struct Curl_addrinfo *res;
#ifdef HAVE_GETADDRINFO
struct addrinfo hints;
#endif
struct thread_data *td; /* for thread-self cleanup */
};
struct thread_data {
#ifdef _WIN32
HANDLE complete_ev;
#endif
curl_thread_t thread_hnd;
unsigned int poll_interval;
timediff_t interval_end;
struct thread_sync_data tsd;
};
static struct thread_sync_data *conn_thread_sync_data(struct Curl_easy *data)
{
return &(data->state.async.tdata->tsd);
}
/* Destroy resolver thread synchronization data */
static
void destroy_thread_sync_data(struct thread_sync_data *tsd)
{
if(tsd->mtx) {
Curl_mutex_destroy(tsd->mtx);
free(tsd->mtx);
}
free(tsd->hostname);
if(tsd->res)
Curl_freeaddrinfo(tsd->res);
#ifndef CURL_DISABLE_SOCKETPAIR
/*
* close one end of the socket pair (may be done in resolver thread);
* the other end (for reading) is always closed in the parent thread.
*/
if(tsd->sock_pair[1] != CURL_SOCKET_BAD) {
wakeup_close(tsd->sock_pair[1]);
}
#endif
memset(tsd, 0, sizeof(*tsd));
}
/* Initialize resolver thread synchronization data */
static
int init_thread_sync_data(struct thread_data *td,
const char *hostname,
int port,
const struct addrinfo *hints)
{
struct thread_sync_data *tsd = &td->tsd;
memset(tsd, 0, sizeof(*tsd));
tsd->td = td;
tsd->port = port;
/* Treat the request as done until the thread actually starts so any early
* cleanup gets done properly.
*/
tsd->done = 1;
#ifdef HAVE_GETADDRINFO
DEBUGASSERT(hints);
tsd->hints = *hints;
#else
(void) hints;
#endif
tsd->mtx = malloc(sizeof(curl_mutex_t));
if(!tsd->mtx)
goto err_exit;
Curl_mutex_init(tsd->mtx);
#ifndef CURL_DISABLE_SOCKETPAIR
/* create socket pair or pipe */
if(wakeup_create(&tsd->sock_pair[0]) < 0) {
tsd->sock_pair[0] = CURL_SOCKET_BAD;
tsd->sock_pair[1] = CURL_SOCKET_BAD;
goto err_exit;
}
#endif
tsd->sock_error = CURL_ASYNC_SUCCESS;
/* Copying hostname string because original can be destroyed by parent
* thread during gethostbyname execution.
*/
tsd->hostname = strdup(hostname);
if(!tsd->hostname)
goto err_exit;
return 1;
err_exit:
#ifndef CURL_DISABLE_SOCKETPAIR
if(tsd->sock_pair[0] != CURL_SOCKET_BAD) {
wakeup_close(tsd->sock_pair[0]);
tsd->sock_pair[0] = CURL_SOCKET_BAD;
}
#endif
destroy_thread_sync_data(tsd);
return 0;
}
static CURLcode getaddrinfo_complete(struct Curl_easy *data)
{
struct thread_sync_data *tsd = conn_thread_sync_data(data);
CURLcode result;
result = Curl_addrinfo_callback(data, tsd->sock_error, tsd->res);
/* The tsd->res structure has been copied to async.dns and perhaps the DNS
cache. Set our copy to NULL so destroy_thread_sync_data doesn't free it.
*/
tsd->res = NULL;
return result;
}
#ifdef _WIN32
static VOID WINAPI
query_complete(DWORD err, DWORD bytes, LPWSAOVERLAPPED overlapped)
{
size_t ss_size;
const ADDRINFOEXW_ *ai;
struct Curl_addrinfo *ca;
struct Curl_addrinfo *cafirst = NULL;
struct Curl_addrinfo *calast = NULL;
#ifdef __clang__
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wcast-align"
#endif
struct thread_sync_data *tsd =
CONTAINING_RECORD(overlapped, struct thread_sync_data, w8.overlapped);
#ifdef __clang__
#pragma clang diagnostic pop
#endif
struct thread_data *td = tsd->td;
const ADDRINFOEXW_ *res = tsd->w8.res;
int error = (int)err;
(void)bytes;
if(error == ERROR_SUCCESS) {
/* traverse the addrinfo list */
for(ai = res; ai != NULL; ai = ai->ai_next) {
size_t namelen = ai->ai_canonname ? wcslen(ai->ai_canonname) + 1 : 0;
/* ignore elements with unsupported address family, */
/* settle family-specific sockaddr structure size. */
if(ai->ai_family == AF_INET)
ss_size = sizeof(struct sockaddr_in);
#ifdef USE_IPV6
else if(ai->ai_family == AF_INET6)
ss_size = sizeof(struct sockaddr_in6);
#endif
else
continue;
/* ignore elements without required address info */
if(!ai->ai_addr || !(ai->ai_addrlen > 0))
continue;
/* ignore elements with bogus address size */
if((size_t)ai->ai_addrlen < ss_size)
continue;
ca = malloc(sizeof(struct Curl_addrinfo) + ss_size + namelen);
if(!ca) {
error = EAI_MEMORY;
break;
}
/* copy each structure member individually, member ordering, */
/* size, or padding might be different for each platform. */
ca->ai_flags = ai->ai_flags;
ca->ai_family = ai->ai_family;
ca->ai_socktype = ai->ai_socktype;
ca->ai_protocol = ai->ai_protocol;
ca->ai_addrlen = (curl_socklen_t)ss_size;
ca->ai_addr = NULL;
ca->ai_canonname = NULL;
ca->ai_next = NULL;
ca->ai_addr = (void *)((char *)ca + sizeof(struct Curl_addrinfo));
memcpy(ca->ai_addr, ai->ai_addr, ss_size);
if(namelen) {
size_t i;
ca->ai_canonname = (void *)((char *)ca->ai_addr + ss_size);
for(i = 0; i < namelen; ++i) /* convert wide string to ascii */
ca->ai_canonname[i] = (char)ai->ai_canonname[i];
ca->ai_canonname[namelen] = '\0';
}
/* if the return list is empty, this becomes the first element */
if(!cafirst)
cafirst = ca;
/* add this element last in the return list */
if(calast)
calast->ai_next = ca;
calast = ca;
}
/* if we failed, also destroy the Curl_addrinfo list */
if(error) {
Curl_freeaddrinfo(cafirst);
cafirst = NULL;
}
else if(!cafirst) {
#ifdef EAI_NONAME
/* rfc3493 conformant */
error = EAI_NONAME;
#else
/* rfc3493 obsoleted */
error = EAI_NODATA;
#endif
#ifdef USE_WINSOCK
SET_SOCKERRNO(error);
#endif
}
tsd->res = cafirst;
}
if(tsd->w8.res) {
Curl_FreeAddrInfoExW(tsd->w8.res);
tsd->w8.res = NULL;
}
if(error) {
tsd->sock_error = SOCKERRNO?SOCKERRNO:error;
if(tsd->sock_error == 0)
tsd->sock_error = RESOLVER_ENOMEM;
}
else {
Curl_addrinfo_set_port(tsd->res, tsd->port);
}
Curl_mutex_acquire(tsd->mtx);
if(tsd->done) {
/* too late, gotta clean up the mess */
Curl_mutex_release(tsd->mtx);
destroy_thread_sync_data(tsd);
free(td);
}
else {
#ifndef CURL_DISABLE_SOCKETPAIR
char buf[1];
if(tsd->sock_pair[1] != CURL_SOCKET_BAD) {
/* DNS has been resolved, signal client task */
buf[0] = 1;
if(swrite(tsd->sock_pair[1], buf, sizeof(buf)) < 0) {
/* update sock_erro to errno */
tsd->sock_error = SOCKERRNO;
}
}
#endif
tsd->done = 1;
Curl_mutex_release(tsd->mtx);
if(td->complete_ev)
SetEvent(td->complete_ev); /* Notify caller that the query completed */
}
}
#endif
#ifdef HAVE_GETADDRINFO
/*
* getaddrinfo_thread() resolves a name and then exits.
*
* For builds without ARES, but with USE_IPV6, create a resolver thread
* and wait on it.
*/
static unsigned int CURL_STDCALL getaddrinfo_thread(void *arg)
{
struct thread_sync_data *tsd = (struct thread_sync_data *)arg;
struct thread_data *td = tsd->td;
char service[12];
int rc;
#ifndef CURL_DISABLE_SOCKETPAIR
char buf[1];
#endif
msnprintf(service, sizeof(service), "%d", tsd->port);
rc = Curl_getaddrinfo_ex(tsd->hostname, service, &tsd->hints, &tsd->res);
if(rc) {
tsd->sock_error = SOCKERRNO?SOCKERRNO:rc;
if(tsd->sock_error == 0)
tsd->sock_error = RESOLVER_ENOMEM;
}
else {
Curl_addrinfo_set_port(tsd->res, tsd->port);
}
Curl_mutex_acquire(tsd->mtx);
if(tsd->done) {
/* too late, gotta clean up the mess */
Curl_mutex_release(tsd->mtx);
destroy_thread_sync_data(tsd);
free(td);
}
else {
#ifndef CURL_DISABLE_SOCKETPAIR
if(tsd->sock_pair[1] != CURL_SOCKET_BAD) {
/* DNS has been resolved, signal client task */
buf[0] = 1;
if(wakeup_write(tsd->sock_pair[1], buf, sizeof(buf)) < 0) {
/* update sock_erro to errno */
tsd->sock_error = SOCKERRNO;
}
}
#endif
tsd->done = 1;
Curl_mutex_release(tsd->mtx);
}
return 0;
}
#else /* HAVE_GETADDRINFO */
/*
* gethostbyname_thread() resolves a name and then exits.
*/
static unsigned int CURL_STDCALL gethostbyname_thread(void *arg)
{
struct thread_sync_data *tsd = (struct thread_sync_data *)arg;
struct thread_data *td = tsd->td;
tsd->res = Curl_ipv4_resolve_r(tsd->hostname, tsd->port);
if(!tsd->res) {
tsd->sock_error = SOCKERRNO;
if(tsd->sock_error == 0)
tsd->sock_error = RESOLVER_ENOMEM;
}
Curl_mutex_acquire(tsd->mtx);
if(tsd->done) {
/* too late, gotta clean up the mess */
Curl_mutex_release(tsd->mtx);
destroy_thread_sync_data(tsd);
free(td);
}
else {
tsd->done = 1;
Curl_mutex_release(tsd->mtx);
}
return 0;
}
#endif /* HAVE_GETADDRINFO */
/*
* destroy_async_data() cleans up async resolver data and thread handle.
*/
static void destroy_async_data(struct Curl_async *async)
{
if(async->tdata) {
struct thread_data *td = async->tdata;
int done;
#ifndef CURL_DISABLE_SOCKETPAIR
curl_socket_t sock_rd = td->tsd.sock_pair[0];
struct Curl_easy *data = td->tsd.data;
#endif
/*
* if the thread is still blocking in the resolve syscall, detach it and
* let the thread do the cleanup...
*/
Curl_mutex_acquire(td->tsd.mtx);
done = td->tsd.done;
td->tsd.done = 1;
Curl_mutex_release(td->tsd.mtx);
if(!done) {
#ifdef _WIN32
if(td->complete_ev) {
CloseHandle(td->complete_ev);
td->complete_ev = NULL;
}
#endif
if(td->thread_hnd != curl_thread_t_null) {
Curl_thread_destroy(td->thread_hnd);
td->thread_hnd = curl_thread_t_null;
}
}
else {
#ifdef _WIN32
if(td->complete_ev) {
Curl_GetAddrInfoExCancel(&td->tsd.w8.cancel_ev);
WaitForSingleObject(td->complete_ev, INFINITE);
CloseHandle(td->complete_ev);
td->complete_ev = NULL;
}
#endif
if(td->thread_hnd != curl_thread_t_null)
Curl_thread_join(&td->thread_hnd);
destroy_thread_sync_data(&td->tsd);
free(async->tdata);
}
#ifndef CURL_DISABLE_SOCKETPAIR
/*
* ensure CURLMOPT_SOCKETFUNCTION fires CURL_POLL_REMOVE
* before the FD is invalidated to avoid EBADF on EPOLL_CTL_DEL
*/
Curl_multi_closed(data, sock_rd);
wakeup_close(sock_rd);
#endif
}
async->tdata = NULL;
free(async->hostname);
async->hostname = NULL;
}
/*
* init_resolve_thread() starts a new thread that performs the actual
* resolve. This function returns before the resolve is done.
*
* Returns FALSE in case of failure, otherwise TRUE.
*/
static bool init_resolve_thread(struct Curl_easy *data,
const char *hostname, int port,
const struct addrinfo *hints)
{
struct thread_data *td = calloc(1, sizeof(struct thread_data));
int err = ENOMEM;
struct Curl_async *asp = &data->state.async;
data->state.async.tdata = td;
if(!td)
goto errno_exit;
asp->port = port;
asp->done = FALSE;
asp->status = 0;
asp->dns = NULL;
td->thread_hnd = curl_thread_t_null;
#ifdef _WIN32
td->complete_ev = NULL;
#endif
if(!init_thread_sync_data(td, hostname, port, hints)) {
asp->tdata = NULL;
free(td);
goto errno_exit;
}
free(asp->hostname);
asp->hostname = strdup(hostname);
if(!asp->hostname)
goto err_exit;
/* The thread will set this to 1 when complete. */
td->tsd.done = 0;
#ifdef _WIN32
if(Curl_isWindows8OrGreater && Curl_FreeAddrInfoExW &&
Curl_GetAddrInfoExCancel && Curl_GetAddrInfoExW) {
#define MAX_NAME_LEN 256 /* max domain name is 253 chars */
#define MAX_PORT_LEN 8
WCHAR namebuf[MAX_NAME_LEN];
WCHAR portbuf[MAX_PORT_LEN];
/* calculate required length */
int w_len = MultiByteToWideChar(CP_UTF8, MB_ERR_INVALID_CHARS, hostname,
-1, NULL, 0);
if((w_len > 0) && (w_len < MAX_NAME_LEN)) {
/* do utf8 conversion */
w_len = MultiByteToWideChar(CP_UTF8, 0, hostname, -1, namebuf, w_len);
if((w_len > 0) && (w_len < MAX_NAME_LEN)) {
swprintf(portbuf, MAX_PORT_LEN, L"%d", port);
td->tsd.w8.hints.ai_family = hints->ai_family;
td->tsd.w8.hints.ai_socktype = hints->ai_socktype;
td->complete_ev = CreateEvent(NULL, TRUE, FALSE, NULL);
if(!td->complete_ev) {
/* failed to start, mark it as done here for proper cleanup. */
td->tsd.done = 1;
goto err_exit;
}
err = Curl_GetAddrInfoExW(namebuf, portbuf, NS_DNS,
NULL, &td->tsd.w8.hints, &td->tsd.w8.res,
NULL, &td->tsd.w8.overlapped,
&query_complete, &td->tsd.w8.cancel_ev);
if(err != WSA_IO_PENDING)
query_complete(err, 0, &td->tsd.w8.overlapped);
return TRUE;
}
}
}
#endif
#ifdef HAVE_GETADDRINFO
td->thread_hnd = Curl_thread_create(getaddrinfo_thread, &td->tsd);
#else
td->thread_hnd = Curl_thread_create(gethostbyname_thread, &td->tsd);
#endif
if(td->thread_hnd == curl_thread_t_null) {
/* The thread never started, so mark it as done here for proper cleanup. */
td->tsd.done = 1;
err = errno;
goto err_exit;
}
return TRUE;
err_exit:
destroy_async_data(asp);
errno_exit:
errno = err;
return FALSE;
}
/*
* 'entry' may be NULL and then no data is returned
*/
static CURLcode thread_wait_resolv(struct Curl_easy *data,
struct Curl_dns_entry **entry,
bool report)
{
struct thread_data *td;
CURLcode result = CURLE_OK;
DEBUGASSERT(data);
td = data->state.async.tdata;
DEBUGASSERT(td);
#ifdef _WIN32
DEBUGASSERT(td->complete_ev || td->thread_hnd != curl_thread_t_null);
#else
DEBUGASSERT(td->thread_hnd != curl_thread_t_null);
#endif
/* wait for the thread to resolve the name */
#ifdef _WIN32
if(td->complete_ev) {
WaitForSingleObject(td->complete_ev, INFINITE);
CloseHandle(td->complete_ev);
td->complete_ev = NULL;
if(entry)
result = getaddrinfo_complete(data);
}
else
#endif
if(Curl_thread_join(&td->thread_hnd)) {
if(entry)
result = getaddrinfo_complete(data);
}
else
DEBUGASSERT(0);
data->state.async.done = TRUE;
if(entry)
*entry = data->state.async.dns;
if(!data->state.async.dns && report)
/* a name was not resolved, report error */
result = Curl_resolver_error(data);
destroy_async_data(&data->state.async);
if(!data->state.async.dns && report)
connclose(data->conn, "asynch resolve failed");
return result;
}
/*
* Until we gain a way to signal the resolver threads to stop early, we must
* simply wait for them and ignore their results.
*/
void Curl_resolver_kill(struct Curl_easy *data)
{
struct thread_data *td = data->state.async.tdata;
/* If we're still resolving, we must wait for the threads to fully clean up,
unfortunately. Otherwise, we can simply cancel to clean up any resolver
data. */
#ifdef _WIN32
if(td && td->complete_ev) {
Curl_GetAddrInfoExCancel(&td->tsd.w8.cancel_ev);
(void)thread_wait_resolv(data, NULL, FALSE);
}
else
#endif
if(td && td->thread_hnd != curl_thread_t_null
&& (data->set.quick_exit != 1L))
(void)thread_wait_resolv(data, NULL, FALSE);
else
Curl_resolver_cancel(data);
}
/*
* Curl_resolver_wait_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,
* CURLE_OPERATION_TIMEDOUT if a time-out occurred, or other errors.
*
* This is the version for resolves-in-a-thread.
*/
CURLcode Curl_resolver_wait_resolv(struct Curl_easy *data,
struct Curl_dns_entry **entry)
{
return thread_wait_resolv(data, entry, TRUE);
}
/*
* Curl_resolver_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.
*/
CURLcode Curl_resolver_is_resolved(struct Curl_easy *data,
struct Curl_dns_entry **entry)
{
struct thread_data *td = data->state.async.tdata;
int done = 0;
DEBUGASSERT(entry);
*entry = NULL;
if(!td) {
DEBUGASSERT(td);
return CURLE_COULDNT_RESOLVE_HOST;
}
Curl_mutex_acquire(td->tsd.mtx);
done = td->tsd.done;
Curl_mutex_release(td->tsd.mtx);
if(done) {
getaddrinfo_complete(data);
if(!data->state.async.dns) {
CURLcode result = Curl_resolver_error(data);
destroy_async_data(&data->state.async);
return result;
}
destroy_async_data(&data->state.async);
*entry = data->state.async.dns;
}
else {
/* poll for name lookup done with exponential backoff up to 250ms */
/* should be fine even if this converts to 32 bit */
timediff_t elapsed = Curl_timediff(Curl_now(),
data->progress.t_startsingle);
if(elapsed < 0)
elapsed = 0;
if(td->poll_interval == 0)
/* Start at 1ms poll interval */
td->poll_interval = 1;
else if(elapsed >= td->interval_end)
/* Back-off exponentially if last interval expired */
td->poll_interval *= 2;
if(td->poll_interval > 250)
td->poll_interval = 250;
td->interval_end = elapsed + td->poll_interval;
Curl_expire(data, td->poll_interval, EXPIRE_ASYNC_NAME);
}
return CURLE_OK;
}
int Curl_resolver_getsock(struct Curl_easy *data, curl_socket_t *socks)
{
int ret_val = 0;
timediff_t milli;
timediff_t ms;
struct resdata *reslv = (struct resdata *)data->state.async.resolver;
#ifndef CURL_DISABLE_SOCKETPAIR
struct thread_data *td = data->state.async.tdata;
#else
(void)socks;
#endif
#ifndef CURL_DISABLE_SOCKETPAIR
if(td) {
/* return read fd to client for polling the DNS resolution status */
socks[0] = td->tsd.sock_pair[0];
td->tsd.data = data;
ret_val = GETSOCK_READSOCK(0);
}
else {
#endif
ms = Curl_timediff(Curl_now(), reslv->start);
if(ms < 3)
milli = 0;
else if(ms <= 50)
milli = ms/3;
else if(ms <= 250)
milli = 50;
else
milli = 200;
Curl_expire(data, milli, EXPIRE_ASYNC_NAME);
#ifndef CURL_DISABLE_SOCKETPAIR
}
#endif
return ret_val;
}
#ifndef HAVE_GETADDRINFO
/*
* Curl_getaddrinfo() - for platforms without getaddrinfo
*/
struct Curl_addrinfo *Curl_resolver_getaddrinfo(struct Curl_easy *data,
const char *hostname,
int port,
int *waitp)
{
struct resdata *reslv = (struct resdata *)data->state.async.resolver;
*waitp = 0; /* default to synchronous response */
reslv->start = Curl_now();
/* fire up a new resolver thread! */
if(init_resolve_thread(data, hostname, port, NULL)) {
*waitp = 1; /* expect asynchronous response */
return NULL;
}
failf(data, "getaddrinfo() thread failed");
return NULL;
}
#else /* !HAVE_GETADDRINFO */
/*
* Curl_resolver_getaddrinfo() - for getaddrinfo
*/
struct Curl_addrinfo *Curl_resolver_getaddrinfo(struct Curl_easy *data,
const char *hostname,
int port,
int *waitp)
{
struct addrinfo hints;
int pf = PF_INET;
struct resdata *reslv = (struct resdata *)data->state.async.resolver;
*waitp = 0; /* default to synchronous response */
#ifdef CURLRES_IPV6
if((data->conn->ip_version != CURL_IPRESOLVE_V4) && Curl_ipv6works(data)) {
/* The stack seems to be IPv6-enabled */
if(data->conn->ip_version == CURL_IPRESOLVE_V6)
pf = PF_INET6;
else
pf = PF_UNSPEC;
}
#endif /* CURLRES_IPV6 */
memset(&hints, 0, sizeof(hints));
hints.ai_family = pf;
hints.ai_socktype = (data->conn->transport == TRNSPRT_TCP)?
SOCK_STREAM : SOCK_DGRAM;
reslv->start = Curl_now();
/* fire up a new resolver thread! */
if(init_resolve_thread(data, hostname, port, &hints)) {
*waitp = 1; /* expect asynchronous response */
return NULL;
}
failf(data, "getaddrinfo() thread failed to start");
return NULL;
}
#endif /* !HAVE_GETADDRINFO */
CURLcode Curl_set_dns_servers(struct Curl_easy *data,
char *servers)
{
(void)data;
(void)servers;
return CURLE_NOT_BUILT_IN;
}
CURLcode Curl_set_dns_interface(struct Curl_easy *data,
const char *interf)
{
(void)data;
(void)interf;
return CURLE_NOT_BUILT_IN;
}
CURLcode Curl_set_dns_local_ip4(struct Curl_easy *data,
const char *local_ip4)
{
(void)data;
(void)local_ip4;
return CURLE_NOT_BUILT_IN;
}
CURLcode Curl_set_dns_local_ip6(struct Curl_easy *data,
const char *local_ip6)
{
(void)data;
(void)local_ip6;
return CURLE_NOT_BUILT_IN;
}
#endif /* CURLRES_THREADED */
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