From e3564201232ed2b7aea2111bb1c5383a8316fadb Mon Sep 17 00:00:00 2001 From: Gisle Vanem Date: Sat, 16 Oct 2004 12:59:05 +0000 Subject: Added Traian Nicolescu's patches for threaded resolver on Windows. Plugged some potential handle and memory leaks. Refs. http://curl.haxx.se/mail/lib-2004-10/0134.html http://curl.haxx.se/mail/lib-2004-10/0157.html --- lib/hostthre.c | 177 +++++++++++++++++++++++++++++++++++++++++++++------------ 1 file changed, 142 insertions(+), 35 deletions(-) diff --git a/lib/hostthre.c b/lib/hostthre.c index 738efa52f..fad335b45 100644 --- a/lib/hostthre.c +++ b/lib/hostthre.c @@ -64,6 +64,7 @@ #endif #ifdef WIN32 +#include #include #endif @@ -156,6 +157,8 @@ struct thread_data { DWORD thread_status; curl_socket_t dummy_sock; /* dummy for Curl_fdset() */ FILE *stderr_file; + HANDLE mutex_waiting; /* marks that we are still waiting for a resolve */ + HANDLE event_resolved; /* marks that the thread obtained the information */ #ifdef CURLRES_IPV6 struct addrinfo hints; #endif @@ -174,7 +177,19 @@ static unsigned __stdcall gethostbyname_thread (void *arg) struct connectdata *conn = (struct connectdata*) arg; struct thread_data *td = (struct thread_data*) conn->async.os_specific; struct hostent *he; - int rc; + int rc = 0; + + /* Duplicate the passed mutex handle. + * This allows us to use it even after the container gets destroyed + * due to a resolver timeout. + */ + HANDLE mutex_waiting = NULL; + if (!DuplicateHandle(GetCurrentProcess(), td->mutex_waiting, + GetCurrentProcess(), &mutex_waiting, 0, FALSE, + DUPLICATE_SAME_ACCESS)) { + /* failed to duplicate the mutex, no point in continuing */ + return 0; + } /* Sharing the same _iob[] element with our parent thread should * hopefully make printouts synchronised. I'm not sure it works @@ -184,16 +199,31 @@ static unsigned __stdcall gethostbyname_thread (void *arg) WSASetLastError (conn->async.status = NO_DATA); /* pending status */ he = gethostbyname (conn->async.hostname); - if (he) { - Curl_addrinfo4_callback(conn, CURL_ASYNC_SUCCESS, he); - rc = 1; - } - else { - Curl_addrinfo4_callback(conn, (int)WSAGetLastError(), NULL); - rc = 0; + + /* is the thread initiator still waiting for us ? */ + if (WaitForSingleObject(mutex_waiting, 0) == WAIT_TIMEOUT) { + /* yes, it is */ + + /* Mark that we have obtained the information, and that we are + * calling back with it. + */ + SetEvent(td->event_resolved); + + if (he) { + Curl_addrinfo4_callback(conn, CURL_ASYNC_SUCCESS, he); + rc = 1; + } + else { + Curl_addrinfo4_callback(conn, (int)WSAGetLastError(), NULL); + rc = 0; + } + TRACE(("Winsock-error %d, addr %s\n", conn->async.status, + he ? inet_ntoa(*(struct in_addr*)he->h_addr) : "unknown")); } - TRACE(("Winsock-error %d, addr %s\n", conn->async.status, - he ? inet_ntoa(*(struct in_addr*)he->h_addr) : "unknown")); + + /* clean up */ + CloseHandle(mutex_waiting); + return (rc); /* An implicit _endthreadex() here */ } @@ -215,6 +245,18 @@ static unsigned __stdcall getaddrinfo_thread (void *arg) char service [NI_MAXSERV]; int rc; + /* Duplicate the passed mutex handle. + * This allows us to use it even after the container gets destroyed + * due to a resolver timeout. + */ + HANDLE mutex_waiting = NULL; + if (!DuplicateHandle(GetCurrentProcess(), td->mutex_waiting, + GetCurrentProcess(), &mutex_waiting, 0, FALSE, + DUPLICATE_SAME_ACCESS)) { + /* failed to duplicate the mutex, no point in continuing */ + return 0; + } + *stderr = *td->stderr_file; itoa(conn->async.port, service, 10); @@ -223,16 +265,30 @@ static unsigned __stdcall getaddrinfo_thread (void *arg) rc = getaddrinfo(conn->async.hostname, service, &td->hints, &res); - if (rc == 0) { + /* is the thread initiator still waiting for us ? */ + if (WaitForSingleObject(mutex_waiting, 0) == WAIT_TIMEOUT) { + /* yes, it is */ + + /* Mark that we have obtained the information, and that we are + * calling back with it. + */ + SetEvent(td->event_resolved); + + if (rc == 0) { #ifdef DEBUG_THREADING_GETADDRINFO - dump_addrinfo (conn, res); + dump_addrinfo (conn, res); #endif - Curl_addrinfo6_callback(conn, CURL_ASYNC_SUCCESS, res); - } - else { - Curl_addrinfo6_callback(conn, (int)WSAGetLastError(), NULL); - TRACE(("Winsock-error %d, no address\n", conn->async.status)); + Curl_addrinfo6_callback(conn, CURL_ASYNC_SUCCESS, res); + } + else { + Curl_addrinfo6_callback(conn, (int)WSAGetLastError(), NULL); + TRACE(("Winsock-error %d, no address\n", conn->async.status)); + } } + + /* clean up */ + CloseHandle(mutex_waiting); + return (rc); /* An implicit _endthreadex() here */ } @@ -248,10 +304,18 @@ static void destroy_thread_data (struct Curl_async *async) free(async->hostname); if (async->os_specific) { - curl_socket_t sock = ((const struct thread_data*)async->os_specific)->dummy_sock; + struct thread_data *td = (struct thread_data*) async->os_specific; + curl_socket_t sock = td->dummy_sock; if (sock != CURL_SOCKET_BAD) sclose(sock); + + /* destroy the synchronization objects */ + if (td->mutex_waiting) + CloseHandle(td->mutex_waiting); + if (td->event_resolved) + CloseHandle(td->event_resolved); + free(async->os_specific); } async->hostname = NULL; @@ -288,8 +352,28 @@ static bool init_resolve_thread (struct connectdata *conn, conn->async.status = 0; conn->async.dns = NULL; conn->async.os_specific = (void*) td; - td->dummy_sock = CURL_SOCKET_BAD; + + /* Create the mutex used to inform the resolver thread that we're + * still waiting, and take initial ownership. + */ + td->mutex_waiting = CreateMutex(NULL, TRUE, NULL); + if (td->mutex_waiting == NULL) { + destroy_thread_data(&conn->async); + SetLastError(EAGAIN); + return FALSE; + } + + /* Create the event that the thread uses to inform us that it's + * done resolving. Do not signal it. + */ + td->event_resolved = CreateEvent(NULL, TRUE, FALSE, NULL); + if (td->event_resolved == NULL) { + destroy_thread_data(&conn->async); + SetLastError(EAGAIN); + return FALSE; + } + td->stderr_file = stderr; td->thread_hnd = (HANDLE) _beginthreadex(NULL, 0, THREAD_FUNC, conn, 0, &td->thread_id); @@ -342,20 +426,43 @@ CURLcode Curl_wait_for_resolv(struct connectdata *conn, CURL_TIMEOUT_RESOLVE; /* default name resolve timeout */ ticks = GetTickCount(); - status = WaitForSingleObject(td->thread_hnd, 1000UL*timeout); - if (status == WAIT_OBJECT_0 || status == WAIT_ABANDONED) { - /* Thread finished before timeout; propagate Winsock error to this thread. - * 'conn->async.done = TRUE' is set in Curl_addrinfo4/6_callback(). - */ - WSASetLastError(conn->async.status); - GetExitCodeThread(td->thread_hnd, &td->thread_status); - TRACE(("%s() status %lu, thread retval %lu, ", - THREAD_NAME, status, td->thread_status)); + /* wait for the thread to resolve the name */ + status = WaitForSingleObject(td->event_resolved, 1000UL*timeout); + + /* mark that we are now done waiting */ + ReleaseMutex(td->mutex_waiting); + + /* close our handle to the mutex, no point in hanging on to it */ + CloseHandle(td->mutex_waiting); + td->mutex_waiting = NULL; + + /* close the event handle, it's useless now */ + CloseHandle(td->event_resolved); + td->event_resolved = NULL; + + /* has the resolver thread succeeded in resolving our query ? */ + if (status == WAIT_OBJECT_0) { + /* wait for the thread to exit, it's in the callback sequence */ + if (WaitForSingleObject(td->thread_hnd, 5000) == WAIT_TIMEOUT) { + TerminateThread(td->thread_hnd, 0); + conn->async.done = TRUE; + td->thread_status = (DWORD)-1; + TRACE(("%s() thread stuck?!, ", THREAD_NAME)); + } + else { + /* Thread finished before timeout; propagate Winsock error to this thread. + * 'conn->async.done = TRUE' is set in Curl_addrinfo4/6_callback(). + */ + WSASetLastError(conn->async.status); + GetExitCodeThread(td->thread_hnd, &td->thread_status); + TRACE(("%s() status %lu, thread retval %lu, ", + THREAD_NAME, status, td->thread_status)); + } } else { - conn->async.done = TRUE; - td->thread_status = (DWORD)-1; - TRACE(("%s() timeout, ", THREAD_NAME)); + conn->async.done = TRUE; + td->thread_status = (DWORD)-1; + TRACE(("%s() timeout, ", THREAD_NAME)); } TRACE(("elapsed %lu ms\n", GetTickCount()-ticks)); @@ -460,8 +567,8 @@ Curl_addrinfo *Curl_getaddrinfo(struct connectdata *conn, } /* fall-back to blocking version */ - infof(data, "init_resolve_thread() failed for %s; code %lu\n", - hostname, GetLastError()); + infof(data, "init_resolve_thread() failed for %s; %s\n", + hostname, Curl_strerror(conn,GetLastError())); h = gethostbyname(hostname); if (!h) { @@ -535,8 +642,8 @@ Curl_addrinfo *Curl_getaddrinfo(struct connectdata *conn, } /* fall-back to blocking version */ - infof(data, "init_resolve_thread() failed for %s; code %lu\n", - hostname, GetLastError()); + infof(data, "init_resolve_thread() failed for %s; %s\n", + hostname, Curl_strerror(conn,GetLastError())); error = getaddrinfo(hostname, sbuf, &hints, &res); if (error) { -- cgit v1.2.3