/***************************************************************************
* _ _ ____ _
* Project ___| | | | _ \| |
* / __| | | | |_) | |
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
* Copyright (C) 1998 - 2022, 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)
# ifdef HAVE_PTHREAD_H
# include <pthread.h>
# endif
#elif defined(USE_THREADS_WIN32)
# ifdef HAVE_PROCESS_H
# include <process.h>
# endif
#endif
#if (defined(NETWARE) && defined(__NOVELL_LIBC__))
#undef in_addr_t
#define in_addr_t unsigned long
#endif
#ifdef HAVE_GETADDRINFO
# define RESOLVER_ENOMEM EAI_MEMORY
#else
# define RESOLVER_ENOMEM ENOMEM
#endif
#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"
#include "socketpair.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;
};
/* Doubly linked list of orphaned thread handles. */
struct thread_list {
curl_thread_t handle;
/* 'exiting' is set true right before an orphaned thread exits.
it should only be set by the orphaned thread from
signal_orphan_is_exiting(). */
bool exiting;
struct thread_list *prev, *next;
};
/* Orphaned threads: A global list of resolver threads that could not be
* completed in time and so they were abandoned by their parent. The list is
* culled periodically by soon-to-be exiting orphans to wait on and destroy
* those that are in the process of or have since exited, which is fast. On
* global cleanup we wait on and destroy any remaining threads, which may be
* slow but at that point we cannot defer it any longer.
*/
struct orphaned_threads {
/* Mutex to lock this. To avoid deadlock the thread-specific thread_sync_data
mutex cannot be used as an inner lock when orphaned_threads is locked. */
curl_mutex_t mutex;
/* List of orphaned threads. */
struct thread_list *first, *last;
/* Count of threads in the list that are in the process of or have exited.
(ie .exiting member of the thread_list item is set true) */
size_t exiting_count;
};
static struct orphaned_threads orphaned_threads;
/* Flags for wait_and_destroy_orphaned_threads().
They're documented above the function definition. */
#define WAIT_DESTROY_ALL (1<<0)
#define WAIT_DESTROY_EXITING_THREADS_ONLY (1<<1)
static void wait_and_destroy_orphaned_threads(int flags);
static void signal_orphan_is_exiting(struct thread_list *orphan);
/*
* Curl_resolver_global_init()
* Called from curl_global_init() to initialize global resolver environment.
*/
int Curl_resolver_global_init(void)
{
memset(&orphaned_threads, 0, sizeof(orphaned_threads));
if(Curl_mutex_init(&orphaned_threads.mutex))
return CURLE_FAILED_INIT;
return CURLE_OK;
}
/*
* Curl_resolver_global_cleanup()
* Called from curl_global_cleanup() to destroy global resolver environment.
*/
void Curl_resolver_global_cleanup(void)
{
/* Take ownership of all orphaned resolver threads and wait for them to exit.
This is necessary because the user may choose to unload the shared library
that is/contains libcurl. */
wait_and_destroy_orphaned_threads(WAIT_DESTROY_ALL);
Curl_mutex_destroy(&orphaned_threads.mutex);
}
/*
* 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);
/* Data for synchronization between resolver thread and its parent */
struct thread_sync_data {
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 {
curl_thread_t thread_hnd;
unsigned int poll_interval;
timediff_t interval_end;
struct thread_sync_data tsd;
/* 'reserved' memory must be available in case the thread is orphaned */
void *reserved;
};
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) {
sclose(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;
if(Curl_mutex_init(tsd->mtx)) {
free(tsd->mtx);
tsd->mtx = NULL;
goto err_exit;
}
#ifndef CURL_DISABLE_SOCKETPAIR
/* create socket pair, avoid AF_LOCAL since it doesn't build on Solaris */
if(Curl_socketpair(AF_UNIX, SOCK_STREAM, 0, &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:
/* Memory allocation failed */
destroy_thread_sync_data(tsd);
return 0;
}
static int getaddrinfo_complete(struct Curl_easy *data)
{
struct thread_sync_data *tsd = conn_thread_sync_data(data);
int rc;
rc = 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 rc;
}
#ifdef HAVE_GETADDRINFO
/*
* getaddrinfo_thread() resolves a name and then exits.
*
* For builds without ARES, but with ENABLE_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;
struct thread_list *orphan = NULL;
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);
orphan = (struct thread_list *)td->reserved;
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(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(orphan)
signal_orphan_is_exiting(orphan);
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;
struct thread_list *orphan = NULL;
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);
orphan = (struct thread_list *)td->reserved;
free(td);
}
else {
tsd->done = 1;
Curl_mutex_release(tsd->mtx);
}
if(orphan)
signal_orphan_is_exiting(orphan);
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
/* We can't wait any longer for the resolver thread so if it's not done
* then it must be orphaned.
*
* 1) add thread to orphaned threads list
* 2) set thread done (this signals to thread it has been orphaned)
*
* An orphaned thread does most of its own cleanup, and any remaining
* cleanup is handled during global cleanup.
*/
Curl_mutex_acquire(td->tsd.mtx);
if(!td->tsd.done && td->thread_hnd != curl_thread_t_null) {
struct thread_list *orphan = (struct thread_list *)td->reserved;
Curl_mutex_acquire(&orphaned_threads.mutex);
#ifdef DEBUGBUILD
{
struct thread_list empty;
memset(&empty, 0, sizeof(empty));
DEBUGASSERT(!memcmp(&empty, orphan, sizeof(empty)));
}
#endif
orphan->handle = td->thread_hnd;
orphan->exiting = false;
if(orphaned_threads.last) {
orphaned_threads.last->next = orphan;
orphan->prev = orphaned_threads.last;
}
else {
orphaned_threads.first = orphan;
orphan->prev = NULL;
}
orphaned_threads.last = orphan;
orphan->next = NULL;
Curl_mutex_release(&orphaned_threads.mutex);
}
done = td->tsd.done;
td->tsd.done = 1;
Curl_mutex_release(td->tsd.mtx);
if(done) {
if(td->thread_hnd != curl_thread_t_null)
Curl_thread_join(&td->thread_hnd);
destroy_thread_sync_data(&td->tsd);
free(td->reserved);
free(td);
}
#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);
sclose(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;
td->reserved = calloc(1, sizeof(struct thread_list));
if(!td->reserved || !init_thread_sync_data(td, hostname, port, hints)) {
asp->tdata = NULL;
free(td->reserved);
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 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);
DEBUGASSERT(td->thread_hnd != curl_thread_t_null);
/* wait for the thread to resolve the name */
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. */
if(td && td->thread_hnd != curl_thread_t_null)
(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(Curl_ipv6works(data))
/* The stack seems to be IPv6-enabled */
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;
}
/* Helper function to wait and destroy some or all orphaned threads.
*
* WAIT_DESTROY_ALL:
* Wait and destroy all orphaned threads. This operation is not safe to specify
* in code that could run in any thread that may be orphaned (ie any resolver
* thread). Waiting on all orphaned threads may take some time. This operation
* must be specified in the call from global cleanup, and ideally nowhere else.
*
* WAIT_DESTROY_EXITING_THREADS_ONLY:
* Wait and destroy only orphaned threads that are in the process of or have
* since exited (ie those with .exiting set true). This is fast.
*
* When the calling thread owns orphaned_threads.mutex it must not call this
* function or deadlock my occur.
*/
static void wait_and_destroy_orphaned_threads(int flags)
{
struct thread_list *thread = NULL;
Curl_mutex_acquire(&orphaned_threads.mutex);
if((flags & WAIT_DESTROY_EXITING_THREADS_ONLY)) {
struct thread_list *p, *next;
struct thread_list *first = NULL, *last = NULL;
if(!orphaned_threads.exiting_count) {
Curl_mutex_release(&orphaned_threads.mutex);
return;
}
for(p = orphaned_threads.first; p; p = next) {
next = p->next;
if(!p->exiting)
continue;
/* remove thread list item from orphaned_threads */
if(p->prev)
p->prev->next = p->next;
if(p->next)
p->next->prev = p->prev;
if(orphaned_threads.first == p)
orphaned_threads.first = p->next;
if(orphaned_threads.last == p)
orphaned_threads.last = p->prev;
/* add thread list item to new thread list */
if(last) {
last->next = p;
p->prev = last;
}
else {
first = p;
p->prev = NULL;
}
last = p;
p->next = NULL;
}
thread = first;
orphaned_threads.exiting_count = 0;
}
else if((flags & WAIT_DESTROY_ALL)) {
thread = orphaned_threads.first;
orphaned_threads.first = NULL;
orphaned_threads.last = NULL;
orphaned_threads.exiting_count = 0;
}
Curl_mutex_release(&orphaned_threads.mutex);
/* Wait and free. Must be done unlocked or there could be deadlock. */
while(thread) {
struct thread_list *next = thread->next;
Curl_thread_join(&thread->handle);
free(thread);
thread = next;
}
}
/* Helper function that must be called from an orphaned thread right before it
exits. */
static void signal_orphan_is_exiting(struct thread_list *orphan)
{
DEBUGASSERT(orphan->handle && !orphan->exiting);
wait_and_destroy_orphaned_threads(WAIT_DESTROY_EXITING_THREADS_ONLY);
Curl_mutex_acquire(&orphaned_threads.mutex);
orphan->exiting = true;
orphaned_threads.exiting_count++;
Curl_mutex_release(&orphaned_threads.mutex);
}
#endif /* CURLRES_THREADED */