CMakeLua/Utilities/cmcurl-7.19.0/lib/hostthre.c

   1 /***************************************************************************
   2  *                                  _   _ ____  _
   3  *  Project                     ___| | | |  _ \| |
   4  *                             / __| | | | |_) | |
   5  *                            | (__| |_| |  _ <| |___
   6  *                             \___|\___/|_| \_\_____|
   7  *
   8  * Copyright (C) 1998 - 2008, Daniel Stenberg, <daniel@haxx.se>, et al.
   9  *
  10  * This software is licensed as described in the file COPYING, which
  11  * you should have received as part of this distribution. The terms
  12  * are also available at http://curl.haxx.se/docs/copyright.html.
  13  *
  14  * You may opt to use, copy, modify, merge, publish, distribute and/or sell
  15  * copies of the Software, and permit persons to whom the Software is
  16  * furnished to do so, under the terms of the COPYING file.
  17  *
  18  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  19  * KIND, either express or implied.
  20  *
  21  * $Id: hostthre.c,v 1.1.1.1 2008-09-23 16:32:05 hoffman Exp $
  22  ***************************************************************************/
  23
  24 #include "setup.h"
  25
  26 #include <string.h>
  27 #include <errno.h>
  28
  29 #ifdef NEED_MALLOC_H
  30 #include <malloc.h>
  31 #endif
  32 #ifdef HAVE_SYS_SOCKET_H
  33 #include <sys/socket.h>
  34 #endif
  35 #ifdef HAVE_NETINET_IN_H
  36 #include <netinet/in.h>
  37 #endif
  38 #ifdef HAVE_NETDB_H
  39 #include <netdb.h>
  40 #endif
  41 #ifdef HAVE_ARPA_INET_H
  42 #include <arpa/inet.h>
  43 #endif
  44 #ifdef HAVE_STDLIB_H
  45 #include <stdlib.h>     /* required for free() prototypes */
  46 #endif
  47 #ifdef HAVE_UNISTD_H
  48 #include <unistd.h>     /* for the close() proto */
  49 #endif
  50 #ifdef  VMS
  51 #include <in.h>
  52 #include <inet.h>
  53 #include <stdlib.h>
  54 #endif
  55
  56 #ifdef HAVE_SETJMP_H
  57 #include <setjmp.h>
  58 #endif
  59
  60 #ifdef HAVE_PROCESS_H
  61 #include <process.h>
  62 #endif
  63
  64 #if (defined(NETWARE) && defined(__NOVELL_LIBC__))
  65 #undef in_addr_t
  66 #define in_addr_t unsigned long
  67 #endif
  68
  69 #include "urldata.h"
  70 #include "sendf.h"
  71 #include "hostip.h"
  72 #include "hash.h"
  73 #include "share.h"
  74 #include "strerror.h"
  75 #include "url.h"
  76 #include "multiif.h"
  77
  78 #define _MPRINTF_REPLACE /* use our functions only */
  79 #include <curl/mprintf.h>
  80
  81 #include "inet_ntop.h"
  82
  83 #include "memory.h"
  84 /* The last #include file should be: */
  85 #include "memdebug.h"
  86
  87 #if defined(_MSC_VER) && defined(CURL_NO__BEGINTHREADEX)
  88 #pragma message ("No _beginthreadex() available in this RTL")
  89 #endif
  90
  91 /***********************************************************************
  92  * Only for Windows threaded name resolves builds
  93  **********************************************************************/
  94 #ifdef CURLRES_THREADED
  95
  96 /* This function is used to init a threaded resolve */
  97 static bool init_resolve_thread(struct connectdata *conn,
  98                                 const char *hostname, int port,
  99                                 const Curl_addrinfo *hints);
 100
 101 #ifdef CURLRES_IPV4
 102   #define THREAD_FUNC  gethostbyname_thread
 103   #define THREAD_NAME "gethostbyname_thread"
 104 #else
 105   #define THREAD_FUNC  getaddrinfo_thread
 106   #define THREAD_NAME "getaddrinfo_thread"
 107 #endif
 108
 109 struct thread_data {
 110   HANDLE thread_hnd;
 111   unsigned thread_id;
 112   DWORD  thread_status;
 113   curl_socket_t dummy_sock;   /* dummy for Curl_resolv_fdset() */
 114   HANDLE mutex_waiting;  /* marks that we are still waiting for a resolve */
 115   HANDLE event_resolved; /* marks that the thread obtained the information */
 116   HANDLE event_thread_started; /* marks that the thread has initialized and
 117                                   started */
 118   HANDLE mutex_terminate; /* serializes access to flag_terminate */
 119   HANDLE event_terminate; /* flag for thread to terminate instead of calling
 120                              callbacks */
 121 #ifdef CURLRES_IPV6
 122   struct addrinfo hints;
 123 #endif
 124 };
 125
 126 /* Data for synchronization between resolver thread and its parent */
 127 struct thread_sync_data {
 128   HANDLE mutex_waiting;   /* thread_data.mutex_waiting duplicate */
 129   HANDLE mutex_terminate; /* thread_data.mutex_terminate duplicate */
 130   HANDLE event_terminate; /* thread_data.event_terminate duplicate */
 131   char * hostname;        /* hostname to resolve, Curl_async.hostname
 132                              duplicate */
 133 };
 134
 135 /* Destroy resolver thread synchronization data */
 136 static
 137 void destroy_thread_sync_data(struct thread_sync_data * tsd)
 138 {
 139   if(tsd->hostname)
 140     free(tsd->hostname);
 141   if(tsd->event_terminate)
 142     CloseHandle(tsd->event_terminate);
 143   if(tsd->mutex_terminate)
 144     CloseHandle(tsd->mutex_terminate);
 145   if(tsd->mutex_waiting)
 146     CloseHandle(tsd->mutex_waiting);
 147   memset(tsd,0,sizeof(*tsd));
 148 }
 149
 150 /* Initialize resolver thread synchronization data */
 151 static
 152 BOOL init_thread_sync_data(struct thread_data * td,
 153                            const char * hostname,
 154                            struct thread_sync_data * tsd)
 155 {
 156   HANDLE curr_proc = GetCurrentProcess();
 157
 158   memset(tsd, 0, sizeof(*tsd));
 159   if(!DuplicateHandle(curr_proc, td->mutex_waiting,
 160                        curr_proc, &tsd->mutex_waiting, 0, FALSE,
 161                        DUPLICATE_SAME_ACCESS)) {
 162     /* failed to duplicate the mutex, no point in continuing */
 163     destroy_thread_sync_data(tsd);
 164     return FALSE;
 165   }
 166   if(!DuplicateHandle(curr_proc, td->mutex_terminate,
 167                        curr_proc, &tsd->mutex_terminate, 0, FALSE,
 168                        DUPLICATE_SAME_ACCESS)) {
 169     /* failed to duplicate the mutex, no point in continuing */
 170     destroy_thread_sync_data(tsd);
 171     return FALSE;
 172   }
 173   if(!DuplicateHandle(curr_proc, td->event_terminate,
 174                        curr_proc, &tsd->event_terminate, 0, FALSE,
 175                        DUPLICATE_SAME_ACCESS)) {
 176     /* failed to duplicate the event, no point in continuing */
 177     destroy_thread_sync_data(tsd);
 178     return FALSE;
 179   }
 180   /* Copying hostname string because original can be destroyed by parent
 181    * thread during gethostbyname execution.
 182    */
 183   tsd->hostname = strdup(hostname);
 184   if(!tsd->hostname) {
 185     /* Memory allocation failed */
 186     destroy_thread_sync_data(tsd);
 187     return FALSE;
 188   }
 189   return TRUE;
 190 }
 191
 192 /* acquire resolver thread synchronization */
 193 static
 194 BOOL acquire_thread_sync(struct thread_sync_data * tsd)
 195 {
 196   /* is the thread initiator still waiting for us ? */
 197   if(WaitForSingleObject(tsd->mutex_waiting, 0) == WAIT_TIMEOUT) {
 198     /* yes, it is */
 199
 200     /* Waiting access to event_terminate */
 201     if(WaitForSingleObject(tsd->mutex_terminate, INFINITE) != WAIT_OBJECT_0) {
 202       /* Something went wrong - now just ignoring */
 203     }
 204     else {
 205       if(WaitForSingleObject(tsd->event_terminate, 0) != WAIT_TIMEOUT) {
 206         /* Parent thread signaled us to terminate.
 207          * This means that all data in conn->async is now destroyed
 208          * and we cannot use it.
 209          */
 210       }
 211       else {
 212         return TRUE;
 213       }
 214     }
 215   }
 216   return FALSE;
 217 }
 218
 219 /* release resolver thread synchronization */
 220 static
 221 void release_thread_sync(struct thread_sync_data * tsd)
 222 {
 223   ReleaseMutex(tsd->mutex_terminate);
 224 }
 225
 226 #if defined(CURLRES_IPV4)
 227 /*
 228  * gethostbyname_thread() resolves a name, calls the Curl_addrinfo4_callback
 229  * and then exits.
 230  *
 231  * For builds without ARES/ENABLE_IPV6, create a resolver thread and wait on
 232  * it.
 233  */
 234 static unsigned __stdcall gethostbyname_thread (void *arg)
 235 {
 236   struct connectdata *conn = (struct connectdata*) arg;
 237   struct thread_data *td = (struct thread_data*) conn->async.os_specific;
 238   struct hostent *he;
 239   int    rc = 0;
 240
 241   /* Duplicate the passed mutex and event handles.
 242    * This allows us to use it even after the container gets destroyed
 243    * due to a resolver timeout.
 244    */
 245   struct thread_sync_data tsd = { 0,0,0,NULL };
 246
 247   if(!init_thread_sync_data(td, conn->async.hostname, &tsd)) {
 248     /* thread synchronization data initialization failed */
 249     return (unsigned)-1;
 250   }
 251
 252   conn->async.status = NO_DATA;  /* pending status */
 253   SET_SOCKERRNO(conn->async.status);
 254
 255   /* Signaling that we have initialized all copies of data and handles we
 256      need */
 257   SetEvent(td->event_thread_started);
 258
 259   he = gethostbyname (tsd.hostname);
 260
 261   /* is parent thread waiting for us and are we able to access conn members? */
 262   if(acquire_thread_sync(&tsd)) {
 263     /* Mark that we have obtained the information, and that we are calling
 264      * back with it. */
 265     SetEvent(td->event_resolved);
 266     if(he) {
 267       rc = Curl_addrinfo4_callback(conn, CURL_ASYNC_SUCCESS, he);
 268     }
 269     else {
 270       rc = Curl_addrinfo4_callback(conn, SOCKERRNO, NULL);
 271     }
 272     release_thread_sync(&tsd);
 273   }
 274
 275   /* clean up */
 276   destroy_thread_sync_data(&tsd);
 277
 278   return (rc);
 279   /* An implicit _endthreadex() here */
 280 }
 281
 282 #elif defined(CURLRES_IPV6)
 283
 284 /*
 285  * getaddrinfo_thread() resolves a name, calls Curl_addrinfo6_callback and then
 286  * exits.
 287  *
 288  * For builds without ARES, but with ENABLE_IPV6, create a resolver thread
 289  * and wait on it.
 290  */
 291 static unsigned __stdcall getaddrinfo_thread (void *arg)
 292 {
 293   struct connectdata *conn = (struct connectdata*) arg;
 294   struct thread_data *td   = (struct thread_data*) conn->async.os_specific;
 295   struct addrinfo    *res;
 296   char   service [NI_MAXSERV];
 297   int    rc;
 298   struct addrinfo hints = td->hints;
 299
 300   /* Duplicate the passed mutex handle.
 301    * This allows us to use it even after the container gets destroyed
 302    * due to a resolver timeout.
 303    */
 304   struct thread_sync_data tsd = { 0,0,0,NULL };
 305
 306   if(!init_thread_sync_data(td, conn->async.hostname, &tsd)) {
 307     /* thread synchronization data initialization failed */
 308     return -1;
 309   }
 310
 311   itoa(conn->async.port, service, 10);
 312
 313   conn->async.status = NO_DATA;  /* pending status */
 314   SET_SOCKERRNO(conn->async.status);
 315
 316   /* Signaling that we have initialized all copies of data and handles we
 317      need */
 318   SetEvent(td->event_thread_started);
 319
 320   rc = getaddrinfo(tsd.hostname, service, &hints, &res);
 321
 322   /* is parent thread waiting for us and are we able to access conn members? */
 323   if(acquire_thread_sync(&tsd)) {
 324     /* Mark that we have obtained the information, and that we are calling
 325        back with it. */
 326     SetEvent(td->event_resolved);
 327
 328     if(rc == 0) {
 329       rc = Curl_addrinfo6_callback(conn, CURL_ASYNC_SUCCESS, res);
 330     }
 331     else {
 332       rc = Curl_addrinfo6_callback(conn, SOCKERRNO, NULL);
 333     }
 334     release_thread_sync(&tsd);
 335   }
 336
 337   /* clean up */
 338   destroy_thread_sync_data(&tsd);
 339
 340   return (rc);
 341   /* An implicit _endthreadex() here */
 342 }
 343 #endif
 344
 345 /*
 346  * Curl_destroy_thread_data() cleans up async resolver data and thread handle.
 347  * Complementary of ares_destroy.
 348  */
 349 void Curl_destroy_thread_data (struct Curl_async *async)
 350 {
 351   if(async->hostname)
 352     free(async->hostname);
 353
 354   if(async->os_specific) {
 355     struct thread_data *td = (struct thread_data*) async->os_specific;
 356     curl_socket_t sock = td->dummy_sock;
 357
 358     if(td->mutex_terminate && td->event_terminate) {
 359       /* Signaling resolver thread to terminate */
 360       if(WaitForSingleObject(td->mutex_terminate, INFINITE) == WAIT_OBJECT_0) {
 361         SetEvent(td->event_terminate);
 362         ReleaseMutex(td->mutex_terminate);
 363       }
 364       else {
 365         /* Something went wrong - just ignoring it */
 366       }
 367     }
 368
 369     if(td->mutex_terminate)
 370       CloseHandle(td->mutex_terminate);
 371     if(td->event_terminate)
 372       CloseHandle(td->event_terminate);
 373     if(td->event_thread_started)
 374       CloseHandle(td->event_thread_started);
 375
 376     if(sock != CURL_SOCKET_BAD)
 377       sclose(sock);
 378
 379     /* destroy the synchronization objects */
 380     if(td->mutex_waiting)
 381       CloseHandle(td->mutex_waiting);
 382     td->mutex_waiting = NULL;
 383     if(td->event_resolved)
 384       CloseHandle(td->event_resolved);
 385
 386     if(td->thread_hnd)
 387       CloseHandle(td->thread_hnd);
 388
 389     free(async->os_specific);
 390   }
 391   async->hostname = NULL;
 392   async->os_specific = NULL;
 393 }
 394
 395 /*
 396  * init_resolve_thread() starts a new thread that performs the actual
 397  * resolve. This function returns before the resolve is done.
 398  *
 399  * Returns FALSE in case of failure, otherwise TRUE.
 400  */
 401 static bool init_resolve_thread (struct connectdata *conn,
 402                                  const char *hostname, int port,
 403                                  const Curl_addrinfo *hints)
 404 {
 405   struct thread_data *td = calloc(sizeof(*td), 1);
 406   HANDLE thread_and_event[2] = {0};
 407
 408   if(!td) {
 409     SET_ERRNO(ENOMEM);
 410     return FALSE;
 411   }
 412
 413   Curl_safefree(conn->async.hostname);
 414   conn->async.hostname = strdup(hostname);
 415   if(!conn->async.hostname) {
 416     free(td);
 417     SET_ERRNO(ENOMEM);
 418     return FALSE;
 419   }
 420
 421   conn->async.port = port;
 422   conn->async.done = FALSE;
 423   conn->async.status = 0;
 424   conn->async.dns = NULL;
 425   conn->async.os_specific = (void*) td;
 426   td->dummy_sock = CURL_SOCKET_BAD;
 427
 428   /* Create the mutex used to inform the resolver thread that we're
 429    * still waiting, and take initial ownership.
 430    */
 431   td->mutex_waiting = CreateMutex(NULL, TRUE, NULL);
 432   if(td->mutex_waiting == NULL) {
 433     Curl_destroy_thread_data(&conn->async);
 434     SET_ERRNO(EAGAIN);
 435     return FALSE;
 436   }
 437
 438   /* Create the event that the thread uses to inform us that it's
 439    * done resolving. Do not signal it.
 440    */
 441   td->event_resolved = CreateEvent(NULL, TRUE, FALSE, NULL);
 442   if(td->event_resolved == NULL) {
 443     Curl_destroy_thread_data(&conn->async);
 444     SET_ERRNO(EAGAIN);
 445     return FALSE;
 446   }
 447   /* Create the mutex used to serialize access to event_terminated
 448    * between us and resolver thread.
 449    */
 450   td->mutex_terminate = CreateMutex(NULL, FALSE, NULL);
 451   if(td->mutex_terminate == NULL) {
 452     Curl_destroy_thread_data(&conn->async);
 453     SET_ERRNO(EAGAIN);
 454     return FALSE;
 455   }
 456   /* Create the event used to signal thread that it should terminate.
 457    */
 458   td->event_terminate = CreateEvent(NULL, TRUE, FALSE, NULL);
 459   if(td->event_terminate == NULL) {
 460     Curl_destroy_thread_data(&conn->async);
 461     SET_ERRNO(EAGAIN);
 462     return FALSE;
 463   }
 464   /* Create the event used by thread to inform it has initialized its own data.
 465    */
 466   td->event_thread_started = CreateEvent(NULL, TRUE, FALSE, NULL);
 467   if(td->event_thread_started == NULL) {
 468     Curl_destroy_thread_data(&conn->async);
 469     SET_ERRNO(EAGAIN);
 470     return FALSE;
 471   }
 472
 473 #ifdef _WIN32_WCE
 474   td->thread_hnd = (HANDLE) CreateThread(NULL, 0,
 475                                          (LPTHREAD_START_ROUTINE) THREAD_FUNC,
 476                                          conn, 0, &td->thread_id);
 477 #else
 478   td->thread_hnd = (HANDLE) _beginthreadex(NULL, 0, THREAD_FUNC,
 479                                            conn, 0, &td->thread_id);
 480 #endif
 481
 482 #ifdef CURLRES_IPV6
 483   DEBUGASSERT(hints);
 484   td->hints = *hints;
 485 #else
 486   (void) hints;
 487 #endif
 488
 489   if(!td->thread_hnd) {
 490 #ifndef _WIN32_WCE
 491      SET_ERRNO(errno);
 492 #endif
 493      Curl_destroy_thread_data(&conn->async);
 494      return FALSE;
 495   }
 496   /* Waiting until the thread will initialize its data or it will exit due errors.
 497    */
 498   thread_and_event[0] = td->thread_hnd;
 499   thread_and_event[1] = td->event_thread_started;
 500   if(WaitForMultipleObjects(sizeof(thread_and_event) /
 501                              sizeof(thread_and_event[0]),
 502                              (const HANDLE*)thread_and_event, FALSE,
 503                              INFINITE) == WAIT_FAILED) {
 504     /* The resolver thread has been created,
 505      * most probably it works now - ignoring this "minor" error
 506      */
 507   }
 508   /* This socket is only to keep Curl_resolv_fdset() and select() happy;
 509    * should never become signalled for read/write since it's unbound but
 510    * Windows needs atleast 1 socket in select().
 511    */
 512   td->dummy_sock = socket(AF_INET, SOCK_DGRAM, 0);
 513   return TRUE;
 514 }
 515
 516
 517 /*
 518  * Curl_wait_for_resolv() waits for a resolve to finish. This function should
 519  * be avoided since using this risk getting the multi interface to "hang".
 520  *
 521  * If 'entry' is non-NULL, make it point to the resolved dns entry
 522  *
 523  * This is the version for resolves-in-a-thread.
 524  */
 525 CURLcode Curl_wait_for_resolv(struct connectdata *conn,
 526                               struct Curl_dns_entry **entry)
 527 {
 528   struct thread_data   *td = (struct thread_data*) conn->async.os_specific;
 529   struct SessionHandle *data = conn->data;
 530   long   timeout;
 531   DWORD  status;
 532   CURLcode rc;
 533
 534   DEBUGASSERT(conn && td);
 535
 536   /* now, see if there's a connect timeout or a regular timeout to
 537      use instead of the default one */
 538   timeout =
 539     conn->data->set.connecttimeout ? conn->data->set.connecttimeout :
 540     conn->data->set.timeout ? conn->data->set.timeout :
 541     CURL_TIMEOUT_RESOLVE * 1000; /* default name resolve timeout */
 542
 543   /* wait for the thread to resolve the name */
 544   status = WaitForSingleObject(td->event_resolved, timeout);
 545
 546   /* mark that we are now done waiting */
 547   ReleaseMutex(td->mutex_waiting);
 548
 549   /* close our handle to the mutex, no point in hanging on to it */
 550   CloseHandle(td->mutex_waiting);
 551   td->mutex_waiting = NULL;
 552
 553   /* close the event handle, it's useless now */
 554   CloseHandle(td->event_resolved);
 555   td->event_resolved = NULL;
 556
 557   /* has the resolver thread succeeded in resolving our query ? */
 558   if(status == WAIT_OBJECT_0) {
 559     /* wait for the thread to exit, it's in the callback sequence */
 560     if(WaitForSingleObject(td->thread_hnd, 5000) == WAIT_TIMEOUT) {
 561       TerminateThread(td->thread_hnd, 0);
 562       conn->async.done = TRUE;
 563       td->thread_status = (DWORD)-1;
 564     }
 565     else {
 566       /* Thread finished before timeout; propagate Winsock error to this
 567        * thread.  'conn->async.done = TRUE' is set in
 568        * Curl_addrinfo4/6_callback().
 569        */
 570       SET_SOCKERRNO(conn->async.status);
 571       GetExitCodeThread(td->thread_hnd, &td->thread_status);
 572     }
 573   }
 574   else {
 575     conn->async.done = TRUE;
 576     td->thread_status = (DWORD)-1;
 577   }
 578
 579   if(entry)
 580     *entry = conn->async.dns;
 581
 582   rc = CURLE_OK;
 583
 584   if(!conn->async.dns) {
 585     /* a name was not resolved */
 586     if(td->thread_status == CURLE_OUT_OF_MEMORY) {
 587       rc = CURLE_OUT_OF_MEMORY;
 588       failf(data, "Could not resolve host: %s", curl_easy_strerror(rc));
 589     }
 590     else if(conn->async.done) {
 591       if(conn->bits.httpproxy) {
 592         failf(data, "Could not resolve proxy: %s; %s",
 593               conn->proxy.dispname, Curl_strerror(conn, conn->async.status));
 594         rc = CURLE_COULDNT_RESOLVE_PROXY;
 595       }
 596       else {
 597         failf(data, "Could not resolve host: %s; %s",
 598               conn->host.name, Curl_strerror(conn, conn->async.status));
 599         rc = CURLE_COULDNT_RESOLVE_HOST;
 600       }
 601     }
 602     else if(td->thread_status == (DWORD)-1 || conn->async.status == NO_DATA) {
 603       failf(data, "Resolving host timed out: %s", conn->host.name);
 604       rc = CURLE_OPERATION_TIMEDOUT;
 605     }
 606     else
 607       rc = CURLE_OPERATION_TIMEDOUT;
 608   }
 609
 610   Curl_destroy_thread_data(&conn->async);
 611
 612   if(!conn->async.dns)
 613     conn->bits.close = TRUE;
 614
 615   return (rc);
 616 }
 617
 618 /*
 619  * Curl_is_resolved() is called repeatedly to check if a previous name resolve
 620  * request has completed. It should also make sure to time-out if the
 621  * operation seems to take too long.
 622  */
 623 CURLcode Curl_is_resolved(struct connectdata *conn,
 624                           struct Curl_dns_entry **entry)
 625 {
 626   struct SessionHandle *data = conn->data;
 627
 628   *entry = NULL;
 629
 630   if(conn->async.done) {
 631     /* we're done */
 632     Curl_destroy_thread_data(&conn->async);
 633     if(!conn->async.dns) {
 634       failf(data, "Could not resolve host: %s; %s",
 635             conn->host.name, Curl_strerror(conn, conn->async.status));
 636       return CURLE_COULDNT_RESOLVE_HOST;
 637     }
 638     *entry = conn->async.dns;
 639   }
 640   return CURLE_OK;
 641 }
 642
 643 int Curl_resolv_getsock(struct connectdata *conn,
 644                         curl_socket_t *socks,
 645                         int numsocks)
 646 {
 647   const struct thread_data *td =
 648     (const struct thread_data *) conn->async.os_specific;
 649
 650   if(td && td->dummy_sock != CURL_SOCKET_BAD) {
 651     if(numsocks) {
 652       /* return one socket waiting for writable, even though this is just
 653          a dummy */
 654       socks[0] = td->dummy_sock;
 655       return GETSOCK_WRITESOCK(0);
 656     }
 657   }
 658   return 0;
 659 }
 660
 661 #ifdef CURLRES_IPV4
 662 /*
 663  * Curl_getaddrinfo() - for Windows threading without ENABLE_IPV6.
 664  */
 665 Curl_addrinfo *Curl_getaddrinfo(struct connectdata *conn,
 666                                 const char *hostname,
 667                                 int port,
 668                                 int *waitp)
 669 {
 670   struct hostent *h = NULL;
 671   struct SessionHandle *data = conn->data;
 672   in_addr_t in;
 673
 674   *waitp = 0; /* don't wait, we act synchronously */
 675
 676   in = inet_addr(hostname);
 677   if(in != CURL_INADDR_NONE)
 678     /* This is a dotted IP address 123.123.123.123-style */
 679     return Curl_ip2addr(in, hostname, port);
 680
 681   /* fire up a new resolver thread! */
 682   if(init_resolve_thread(conn, hostname, port, NULL)) {
 683     *waitp = TRUE;  /* please wait for the response */
 684     return NULL;
 685   }
 686
 687   /* fall-back to blocking version */
 688   infof(data, "init_resolve_thread() failed for %s; %s\n",
 689         hostname, Curl_strerror(conn, ERRNO));
 690
 691   h = gethostbyname(hostname);
 692   if(!h) {
 693     infof(data, "gethostbyname(2) failed for %s:%d; %s\n",
 694           hostname, port, Curl_strerror(conn, SOCKERRNO));
 695     return NULL;
 696   }
 697   return Curl_he2ai(h, port);
 698 }
 699 #endif /* CURLRES_IPV4 */
 700
 701 #ifdef CURLRES_IPV6
 702 /*
 703  * Curl_getaddrinfo() - for Windows threading IPv6 enabled
 704  */
 705 Curl_addrinfo *Curl_getaddrinfo(struct connectdata *conn,
 706                                 const char *hostname,
 707                                 int port,
 708                                 int *waitp)
 709 {
 710   struct addrinfo hints, *res;
 711   int error;
 712   char sbuf[NI_MAXSERV];
 713   int pf;
 714   struct SessionHandle *data = conn->data;
 715
 716   *waitp = FALSE; /* default to synch response */
 717
 718   /*
 719    * Check if a limited name resolve has been requested.
 720    */
 721   switch(data->set.ip_version) {
 722   case CURL_IPRESOLVE_V4:
 723     pf = PF_INET;
 724     break;
 725   case CURL_IPRESOLVE_V6:
 726     pf = PF_INET6;
 727     break;
 728   default:
 729     pf = PF_UNSPEC;
 730     break;
 731   }
 732
 733   if (pf != PF_INET) {
 734     /* see if we have an IPv6 stack */
 735     curl_socket_t s = socket(PF_INET6, SOCK_DGRAM, 0);
 736     if(s == CURL_SOCKET_BAD) {
 737       /* Some non-IPv6 stacks have been found to make very slow name resolves
 738        * when PF_UNSPEC is used, so thus we switch to a mere PF_INET lookup if
 739        * the stack seems to be a non-ipv6 one. */
 740
 741       pf = PF_INET;
 742     }
 743     else {
 744       /* This seems to be an IPv6-capable stack, use PF_UNSPEC for the widest
 745        * possible checks. And close the socket again.
 746        */
 747       sclose(s);
 748     }
 749   }
 750
 751   memset(&hints, 0, sizeof(hints));
 752   hints.ai_family = pf;
 753   hints.ai_socktype = conn->socktype;
 754 #if 0 /* removed nov 8 2005 before 7.15.1 */
 755   hints.ai_flags = AI_CANONNAME;
 756 #endif
 757   itoa(port, sbuf, 10);
 758
 759   /* fire up a new resolver thread! */
 760   if(init_resolve_thread(conn, hostname, port, &hints)) {
 761     *waitp = TRUE;  /* please wait for the response */
 762     return NULL;
 763   }
 764
 765   /* fall-back to blocking version */
 766   infof(data, "init_resolve_thread() failed for %s; %s\n",
 767         hostname, Curl_strerror(conn, ERRNO));
 768
 769   error = getaddrinfo(hostname, sbuf, &hints, &res);
 770   if(error) {
 771     infof(data, "getaddrinfo() failed for %s:%d; %s\n",
 772           hostname, port, Curl_strerror(conn, SOCKERRNO));
 773     return NULL;
 774   }
 775   return res;
 776 }
 777 #endif /* CURLRES_IPV6 */
 778 #endif /* CURLRES_THREADED */