curl/lib/curl_threads.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

155 lines
3.6 KiB
C

/***************************************************************************
* _ _ ____ _
* 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 <curl/curl.h>
#if defined(USE_THREADS_POSIX)
# ifdef HAVE_PTHREAD_H
# include <pthread.h>
# endif
#elif defined(USE_THREADS_WIN32)
# include <process.h>
#endif
#include "curl_threads.h"
#include "curl_memory.h"
/* The last #include file should be: */
#include "memdebug.h"
#if defined(USE_THREADS_POSIX)
struct Curl_actual_call {
unsigned int (*func)(void *);
void *arg;
};
static void *curl_thread_create_thunk(void *arg)
{
struct Curl_actual_call *ac = arg;
unsigned int (*func)(void *) = ac->func;
void *real_arg = ac->arg;
free(ac);
(*func)(real_arg);
return 0;
}
curl_thread_t Curl_thread_create(unsigned int (*func) (void *), void *arg)
{
curl_thread_t t = malloc(sizeof(pthread_t));
struct Curl_actual_call *ac = malloc(sizeof(struct Curl_actual_call));
if(!(ac && t))
goto err;
ac->func = func;
ac->arg = arg;
if(pthread_create(t, NULL, curl_thread_create_thunk, ac) != 0)
goto err;
return t;
err:
free(t);
free(ac);
return curl_thread_t_null;
}
void Curl_thread_destroy(curl_thread_t hnd)
{
if(hnd != curl_thread_t_null) {
pthread_detach(*hnd);
free(hnd);
}
}
int Curl_thread_join(curl_thread_t *hnd)
{
int ret = (pthread_join(**hnd, NULL) == 0);
free(*hnd);
*hnd = curl_thread_t_null;
return ret;
}
#elif defined(USE_THREADS_WIN32)
/* !checksrc! disable SPACEBEFOREPAREN 1 */
curl_thread_t Curl_thread_create(unsigned int (CURL_STDCALL *func) (void *),
void *arg)
{
#ifdef _WIN32_WCE
typedef HANDLE curl_win_thread_handle_t;
#else
typedef uintptr_t curl_win_thread_handle_t;
#endif
curl_thread_t t;
curl_win_thread_handle_t thread_handle;
#ifdef _WIN32_WCE
thread_handle = CreateThread(NULL, 0, func, arg, 0, NULL);
#else
thread_handle = _beginthreadex(NULL, 0, func, arg, 0, NULL);
#endif
t = (curl_thread_t)thread_handle;
if((t == 0) || (t == LongToHandle(-1L))) {
#ifdef _WIN32_WCE
DWORD gle = GetLastError();
errno = ((gle == ERROR_ACCESS_DENIED ||
gle == ERROR_NOT_ENOUGH_MEMORY) ?
EACCES : EINVAL);
#endif
return curl_thread_t_null;
}
return t;
}
void Curl_thread_destroy(curl_thread_t hnd)
{
if(hnd != curl_thread_t_null)
CloseHandle(hnd);
}
int Curl_thread_join(curl_thread_t *hnd)
{
#if !defined(_WIN32_WINNT) || !defined(_WIN32_WINNT_VISTA) || \
(_WIN32_WINNT < _WIN32_WINNT_VISTA)
int ret = (WaitForSingleObject(*hnd, INFINITE) == WAIT_OBJECT_0);
#else
int ret = (WaitForSingleObjectEx(*hnd, INFINITE, FALSE) == WAIT_OBJECT_0);
#endif
Curl_thread_destroy(*hnd);
*hnd = curl_thread_t_null;
return ret;
}
#endif /* USE_THREADS_* */