/*************************************************************************** * _ _ ____ _ * Project ___| | | | _ \| | * / __| | | | |_) | | * | (__| |_| | _ <| |___ * \___|\___/|_| \_\_____| * * Copyright (C) 1998 - 2022, Daniel Stenberg, , 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 #endif #ifdef HAVE_NETDB_H #include #endif #ifdef HAVE_ARPA_INET_H #include #endif #ifdef __VMS #include #include #endif #if defined(USE_THREADS_POSIX) # ifdef HAVE_PTHREAD_H # include # endif #elif defined(USE_THREADS_WIN32) # ifdef HAVE_PROCESS_H # include # 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; }; /* * 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); /* 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; }; 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; Curl_mutex_init(tsd->mtx); #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: #ifndef CURL_DISABLE_SOCKETPAIR if(tsd->sock_pair[0] != CURL_SOCKET_BAD) { sclose(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 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; 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(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); } 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) { Curl_thread_destroy(td->thread_hnd); } else { 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); 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; 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 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) { /* 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; } #endif /* CURLRES_THREADED */