romenskiy2012/curl
1
0
Fork 0
mirror of https://github.com/curl/curl.git synced 2026-04-15 01:21:44 +03:00
Code Issues Projects Releases Packages Wiki Activity
curl/lib/curl_share.c
Stefan Eissing 82009c4220
share: concurrency handling, easy updates 
Replace the `volatile int dirty` with a reference counter
protected by a mutex when available.

Solve the problem of when to call application's lock function
by adding a volatile flag that indicates a share has been added
to easy handles in its lifetime. That flag ever goes from
FALSE to TRUE, so volatile might work (in the absence of a mutex).

(The problem is that the lock/unlock functions need 2-3
`curl_share_setopt()` invocations to become usable and there
is no way of telling if the third will ever happen. Calling
the lock function before the 3rd setopt may crash the
application.)

When removing a share from an easy handle (or replacing it with
another share), detach the easy connection on a share with a
connection pool.

When cleaning up a share, allow this even if it is still used in
easy handles. It will be destroyed when the reference count
drops to 0.

Closes #20870
2026-03-21 14:42:49 +01:00

475 lines
12 KiB
C
Raw Blame History

/***************************************************************************
* _ _ ____ _
* 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 "urldata.h"
#include "multiif.h"
#include "curl_threads.h"
#include "curl_share.h"
#include "vtls/vtls.h"
#include "vtls/vtls_scache.h"
#include "hsts.h"
#include "url.h"
static void share_destroy(struct Curl_share *share)
{
if(share->specifier & (1 << CURL_LOCK_DATA_CONNECT)) {
Curl_cpool_destroy(&share->cpool);
}
Curl_dnscache_destroy(&share->dnscache);
#if !defined(CURL_DISABLE_HTTP) && !defined(CURL_DISABLE_COOKIES)
Curl_cookie_cleanup(share->cookies);
#endif
#ifndef CURL_DISABLE_HSTS
Curl_hsts_cleanup(&share->hsts);
#endif
#ifdef USE_SSL
if(share->ssl_scache) {
Curl_ssl_scache_destroy(share->ssl_scache);
share->ssl_scache = NULL;
}
#endif
Curl_psl_destroy(&share->psl);
Curl_close(&share->admin);
#ifdef USE_MUTEX
Curl_mutex_destroy(&share->lock);
#endif
share->magic = 0;
curlx_free(share);
}
CURLSH *curl_share_init(void)
{
struct Curl_share *share = curlx_calloc(1, sizeof(struct Curl_share));
if(share) {
share->magic = CURL_GOOD_SHARE;
share->specifier |= (1 << CURL_LOCK_DATA_SHARE);
#ifdef USE_MUTEX
Curl_mutex_init(&share->lock);
#endif
share->ref_count = 1;
Curl_dnscache_init(&share->dnscache, 23);
share->admin = curl_easy_init();
if(!share->admin) {
share_destroy(share);
return NULL;
}
/* admin handles have mid 0 */
share->admin->mid = 0;
share->admin->state.internal = TRUE;
#ifdef DEBUGBUILD
if(getenv("CURL_DEBUG"))
share->admin->set.verbose = TRUE;
#endif
}
return share;
}
static uint32_t share_ref_inc(struct Curl_share *share)
{
uint32_t n;
#ifdef USE_MUTEX
Curl_mutex_acquire(&share->lock);
n = ++(share->ref_count);
share->has_been_shared = TRUE;
Curl_mutex_release(&share->lock);
#else
n = ++(share->ref_count);
share->has_been_shared = TRUE;
#endif
return n;
}
static uint32_t share_ref_dec(struct Curl_share *share)
{
uint32_t n;
#ifdef USE_MUTEX
Curl_mutex_acquire(&share->lock);
DEBUGASSERT(share->ref_count);
n = --(share->ref_count);
Curl_mutex_release(&share->lock);
#else
n = --(share->ref_count);
#endif
return n;
}
static bool share_has_been_shared(struct Curl_share *share)
{
bool was_shared;
#ifdef USE_MUTEX
Curl_mutex_acquire(&share->lock);
was_shared = share->has_been_shared;
Curl_mutex_release(&share->lock);
#else
was_shared = share->has_been_shared;
#endif
return was_shared;
}
static bool share_lock_acquire(struct Curl_share *share,
struct Curl_easy *data)
{
if(share->lockfunc && share->unlockfunc &&
(data || share_has_been_shared(share))) {
share->lockfunc(data, CURL_LOCK_DATA_SHARE, CURL_LOCK_ACCESS_SINGLE,
share->clientdata);
return TRUE;
}
return FALSE;
}
static void share_lock_release(struct Curl_share *share,
struct Curl_easy *data,
bool locked)
{
if(locked) {
DEBUGASSERT(share->unlockfunc);
if(share->unlockfunc)
share->unlockfunc(data, CURL_LOCK_DATA_SHARE, share->clientdata);
}
}
static bool share_in_use(struct Curl_share *share)
{
bool in_use;
#ifdef USE_MUTEX
Curl_mutex_acquire(&share->lock);
in_use = (share->ref_count > 1);
Curl_mutex_release(&share->lock);
#else
bool locked = share_lock_acquire(share, NULL);
in_use = (share->ref_count > 1);
share_lock_release(share, NULL, locked);
#endif
return in_use;
}
static void share_unlink(struct Curl_share **pshare,
struct Curl_easy *data,
bool locked)
{
struct Curl_share *share = *pshare;
uint32_t n;
*pshare = NULL;
n = share_ref_dec(share);
if(locked)
share_lock_release(share, data, locked);
if(!n) /* last reference gone */
share_destroy(share);
}
#undef curl_share_setopt
CURLSHcode curl_share_setopt(CURLSH *sh, CURLSHoption option, ...)
{
va_list param;
int type;
curl_lock_function lockfunc;
curl_unlock_function unlockfunc;
void *ptr;
CURLSHcode res = CURLSHE_OK;
struct Curl_share *share = sh;
if(!GOOD_SHARE_HANDLE(share))
return CURLSHE_INVALID;
if(share_in_use(share)) {
/* do not allow setting options while one or more handles are already
using this share */
return CURLSHE_IN_USE;
}
va_start(param, option);
switch(option) {
case CURLSHOPT_SHARE:
/* this is a type this share will share */
type = va_arg(param, int);
switch(type) {
case CURL_LOCK_DATA_DNS:
break;
case CURL_LOCK_DATA_COOKIE:
#if !defined(CURL_DISABLE_HTTP) && !defined(CURL_DISABLE_COOKIES)
if(!share->cookies) {
share->cookies = Curl_cookie_init();
if(!share->cookies)
res = CURLSHE_NOMEM;
}
#else /* CURL_DISABLE_HTTP || CURL_DISABLE_COOKIES */
res = CURLSHE_NOT_BUILT_IN;
#endif
break;
case CURL_LOCK_DATA_HSTS:
#ifndef CURL_DISABLE_HSTS
if(!share->hsts) {
share->hsts = Curl_hsts_init();
if(!share->hsts)
res = CURLSHE_NOMEM;
}
#else /* CURL_DISABLE_HSTS */
res = CURLSHE_NOT_BUILT_IN;
#endif
break;
case CURL_LOCK_DATA_SSL_SESSION:
#ifdef USE_SSL
if(!share->ssl_scache) {
/* There is no way (yet) for the application to configure the
* session cache size, shared between many transfers. As for curl
* itself, a high session count will impact startup time. Also, the
* scache is not optimized for several hundreds of peers.
* Keep it at a reasonable level. */
if(Curl_ssl_scache_create(25, 2, &share->ssl_scache))
res = CURLSHE_NOMEM;
}
#else
res = CURLSHE_NOT_BUILT_IN;
#endif
break;
case CURL_LOCK_DATA_CONNECT:
/* It is safe to set this option several times on a share. */
if(!share->cpool.initialised) {
Curl_cpool_init(&share->cpool, share->admin, share, 103);
}
break;
case CURL_LOCK_DATA_PSL:
#ifndef USE_LIBPSL
res = CURLSHE_NOT_BUILT_IN;
#endif
break;
default:
res = CURLSHE_BAD_OPTION;
}
if(!res)
share->specifier |= (unsigned int)(1 << type);
break;
case CURLSHOPT_UNSHARE:
/* this is a type this share will no longer share */
type = va_arg(param, int);
share->specifier &= ~(unsigned int)(1 << type);
switch(type) {
case CURL_LOCK_DATA_DNS:
break;
case CURL_LOCK_DATA_COOKIE:
#if !defined(CURL_DISABLE_HTTP) && !defined(CURL_DISABLE_COOKIES)
if(share->cookies) {
Curl_cookie_cleanup(share->cookies);
share->cookies = NULL;
}
#else /* CURL_DISABLE_HTTP || CURL_DISABLE_COOKIES */
res = CURLSHE_NOT_BUILT_IN;
#endif
break;
case CURL_LOCK_DATA_HSTS:
#ifndef CURL_DISABLE_HSTS
if(share->hsts) {
Curl_hsts_cleanup(&share->hsts);
}
#else /* CURL_DISABLE_HSTS */
res = CURLSHE_NOT_BUILT_IN;
#endif
break;
case CURL_LOCK_DATA_SSL_SESSION:
#ifdef USE_SSL
if(share->ssl_scache) {
Curl_ssl_scache_destroy(share->ssl_scache);
share->ssl_scache = NULL;
}
#else
res = CURLSHE_NOT_BUILT_IN;
#endif
break;
case CURL_LOCK_DATA_CONNECT:
break;
default:
res = CURLSHE_BAD_OPTION;
break;
}
break;
case CURLSHOPT_LOCKFUNC:
lockfunc = va_arg(param, curl_lock_function);
share->lockfunc = lockfunc;
break;
case CURLSHOPT_UNLOCKFUNC:
unlockfunc = va_arg(param, curl_unlock_function);
share->unlockfunc = unlockfunc;
break;
case CURLSHOPT_USERDATA:
ptr = va_arg(param, void *);
share->clientdata = ptr;
break;
default:
res = CURLSHE_BAD_OPTION;
break;
}
va_end(param);
return res;
}
CURLSHcode curl_share_cleanup(CURLSH *sh)
{
struct Curl_share *share = sh;
bool locked;
if(!GOOD_SHARE_HANDLE(share))
return CURLSHE_INVALID;
if(share_in_use(share))
return CURLSHE_IN_USE;
locked = share_lock_acquire(share, NULL);
share_unlink(&share, NULL, locked);
return CURLSHE_OK;
}
CURLSHcode Curl_share_lock(struct Curl_easy *data, curl_lock_data type,
curl_lock_access accesstype)
{
struct Curl_share *share = data->share;
if(!share)
return CURLSHE_INVALID;
if(share->specifier & (unsigned int)(1 << type)) {
if(share->lockfunc) /* only call this if set! */
share->lockfunc(data, type, accesstype, share->clientdata);
}
/* else if we do not share this, pretend successful lock */
return CURLSHE_OK;
}
CURLSHcode Curl_share_unlock(struct Curl_easy *data, curl_lock_data type)
{
struct Curl_share *share = data->share;
if(!share)
return CURLSHE_INVALID;
if(share->specifier & (unsigned int)(1 << type)) {
if(share->unlockfunc) /* only call this if set! */
share->unlockfunc(data, type, share->clientdata);
}
return CURLSHE_OK;
}
CURLcode Curl_share_easy_unlink(struct Curl_easy *data)
{
struct Curl_share *share = data->share;
if(share) {
bool locked = share_lock_acquire(share, data);
/* If data has a connection from this share, detach it. */
if(data->conn && (share->specifier & (1 << CURL_LOCK_DATA_CONNECT)))
Curl_detach_connection(data);
#if !defined(CURL_DISABLE_HTTP) && !defined(CURL_DISABLE_COOKIES)
if(share->cookies == data->cookies)
data->cookies = NULL;
#endif
#ifndef CURL_DISABLE_HSTS
if(share->hsts == data->hsts)
data->hsts = NULL;
#endif
#ifdef USE_LIBPSL
if(&share->psl == data->psl)
data->psl = data->multi ? &data->multi->psl : NULL;
#endif
if(share->specifier & (1 << CURL_LOCK_DATA_DNS)) {
Curl_dns_entry_unlink(data, &data->state.dns[0]);
Curl_dns_entry_unlink(data, &data->state.dns[1]);
}
share_unlink(&data->share, data, locked);
}
return CURLE_OK;
}
CURLcode Curl_share_easy_link(struct Curl_easy *data,
struct Curl_share *share)
{
if(data->share) {
DEBUGASSERT(0);
return CURLE_FAILED_INIT;
}
if(share) {
bool locked = share_lock_acquire(share, data);
share_ref_inc(share);
data->share = share;
#if !defined(CURL_DISABLE_HTTP) && !defined(CURL_DISABLE_COOKIES)
if(share->cookies) {
/* use shared cookie list, first free own one if any */
Curl_cookie_cleanup(data->cookies);
/* enable cookies since we now use a share that uses cookies! */
data->cookies = share->cookies;
}
#endif /* CURL_DISABLE_HTTP */
#ifndef CURL_DISABLE_HSTS
if(share->hsts) {
/* first free the private one if any */
Curl_hsts_cleanup(&data->hsts);
data->hsts = share->hsts;
}
#endif
#ifdef USE_LIBPSL
if(share->specifier & (1 << CURL_LOCK_DATA_PSL))
data->psl = &share->psl;
#endif
/* check for host cache not needed,
* it will be done by curl_easy_perform */
share_lock_release(share, data, locked);
}
return CURLE_OK;
}
Reference in a new issue View git blame Copy permalink