aboutsummaryrefslogtreecommitdiff
path: root/lib/asyn-thread.c
blob: 8cb92d76ec0cbf9313270382031fd7c458598d77 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
/***************************************************************************
 *                                  _   _ ____  _
 *  Project                     ___| | | |  _ \| |
 *                             / __| | | | |_) | |
 *                            | (__| |_| |  _ <| |___
 *                             \___|\___/|_| \_\_____|
 *
 * Copyright (C) 1998 - 2011, 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 http://curl.haxx.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.
 *
 ***************************************************************************/

#include "setup.h"

#include <string.h>
#include <errno.h>

#ifdef HAVE_SYS_SOCKET_H
#include <sys/socket.h>
#endif
#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 HAVE_STDLIB_H
#include <stdlib.h>     /* required for free() prototypes */
#endif
#ifdef HAVE_UNISTD_H
#include <unistd.h>     /* for the close() proto */
#endif
#ifdef __VMS
#include <in.h>
#include <inet.h>
#include <stdlib.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 "strerror.h"
#include "url.h"
#include "multiif.h"
#include "inet_pton.h"
#include "inet_ntop.h"
#include "curl_threads.h"

#define _MPRINTF_REPLACE /* use our functions only */
#include <curl/mprintf.h>

#include "curl_memory.h"
/* The last #include file should be: */
#include "memdebug.h"

/***********************************************************************
 * Only for threaded name resolves builds
 **********************************************************************/
#ifdef CURLRES_THREADED

/*
 * 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).  Does nothing here.
 */
CURLcode Curl_resolver_init(void **resolver)
{
  (void)resolver;
  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).  Does nothing here.
 */
void Curl_resolver_cleanup(void *resolver)
{
  (void)resolver;
}

/*
 * Curl_resolver_duphandle()
 * Called from curl_easy_duphandle() to duplicate resolver URL state-specific
 * environment ('resolver' member of the UrlState structure).  Does nothing
 * here.
 */
int Curl_resolver_duphandle(void **to, void *from)
{
  (void)to;
  (void)from;
  return CURLE_OK;
}

static void destroy_async_data(struct Curl_async *);

/*
 * Cancel all possibly still on-going resolves for this connection.
 */
void Curl_resolver_cancel(struct connectdata *conn)
{
  destroy_async_data(&conn->async);
}

/* This function is used to init a threaded resolve */
static bool init_resolve_thread(struct connectdata *conn,
                                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;

  char * hostname;        /* hostname to resolve, Curl_async.hostname
                             duplicate */
  int port;
  int sock_error;
  Curl_addrinfo *res;
#ifdef HAVE_GETADDRINFO
  struct addrinfo hints;
#endif
};

struct thread_data {
  curl_thread_t thread_hnd;
  curl_socket_t dummy_sock;
  unsigned int poll_interval;
  int interval_end;
  struct thread_sync_data tsd;
};

static struct thread_sync_data *conn_thread_sync_data(struct connectdata *conn)
{
  return &(((struct thread_data *)conn->async.os_specific)->tsd);
}

#define CONN_THREAD_SYNC_DATA(conn) &(((conn)->async.os_specific)->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);
  }

  if(tsd->hostname)
    free(tsd->hostname);

  if(tsd->res)
    Curl_freeaddrinfo(tsd->res);

  memset(tsd,0,sizeof(*tsd));
}

/* Initialize resolver thread synchronization data */
static
int init_thread_sync_data(struct thread_sync_data * tsd,
                           const char * hostname,
                           int port,
                           const struct addrinfo *hints)
{
  memset(tsd, 0, sizeof(*tsd));

  tsd->port = port;
#ifdef CURLRES_IPV6
  DEBUGASSERT(hints);
  tsd->hints = *hints;
#else
  (void) hints;
#endif

  tsd->mtx = malloc(sizeof(curl_mutex_t));
  if(tsd->mtx == NULL)
    goto err_exit;

  Curl_mutex_init(tsd->mtx);

  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 connectdata *conn)
{
  struct thread_sync_data *tsd = conn_thread_sync_data(conn);
  int rc;

  rc = Curl_addrinfo_callback(conn, 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;
  char   service [NI_MAXSERV];
  int rc;

  snprintf(service, sizeof(service), "%d", tsd->port);

  rc = Curl_getaddrinfo_ex(tsd->hostname, service, &tsd->hints, &tsd->res);

  if(rc != 0) {
    tsd->sock_error = SOCKERRNO?SOCKERRNO:rc;
    if(tsd->sock_error == 0)
      tsd->sock_error = RESOLVER_ENOMEM;
  }

  Curl_mutex_acquire(tsd->mtx);
  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;

  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);
  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->hostname)
    free(async->hostname);

  if(async->os_specific) {
    struct thread_data *td = (struct thread_data*) async->os_specific;

    if(td->dummy_sock != CURL_SOCKET_BAD)
      sclose(td->dummy_sock);

    if(td->thread_hnd != curl_thread_t_null)
      Curl_thread_join(&td->thread_hnd);

    destroy_thread_sync_data(&td->tsd);

    free(async->os_specific);
  }
  async->hostname = NULL;
  async->os_specific = 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 connectdata *conn,
                                 const char *hostname, int port,
                                 const struct addrinfo *hints)
{
  struct thread_data *td = calloc(1, sizeof(struct thread_data));
  int err = RESOLVER_ENOMEM;

  conn->async.os_specific = (void*) td;
  if(!td)
    goto err_exit;

  conn->async.port = port;
  conn->async.done = FALSE;
  conn->async.status = 0;
  conn->async.dns = NULL;
  td->dummy_sock = CURL_SOCKET_BAD;
  td->thread_hnd = curl_thread_t_null;

  if(!init_thread_sync_data(&td->tsd, hostname, port, hints))
    goto err_exit;

  Curl_safefree(conn->async.hostname);
  conn->async.hostname = strdup(hostname);
  if(!conn->async.hostname)
    goto err_exit;

#ifdef WIN32
  /* This socket is only to keep Curl_resolver_fdset() and select() happy;
   * should never become signalled for read since it's unbound but
   * Windows needs at least 1 socket in select().
   */
  td->dummy_sock = socket(AF_INET, SOCK_DGRAM, 0);
  if(td->dummy_sock == CURL_SOCKET_BAD)
    goto err_exit;
#endif

#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) {
#ifndef _WIN32_WCE
    err = errno;
#endif
    goto err_exit;
  }

  return TRUE;

 err_exit:
  destroy_async_data(&conn->async);

  SET_ERRNO(err);

  return FALSE;
}

#if defined(HAVE_GETADDRINFO) && !defined(HAVE_GAI_STRERROR) && !defined(WIN32)
/* NetWare has getaddrinfo but lacks gai_strerror.
   Windows has a gai_strerror but it is bad (not thread-safe) and the generic
   socket error string function can be used for this pupose. */
static const char *gai_strerror(int ecode)
{
  switch (ecode) {
  case EAI_AGAIN:
    return "The name could not be resolved at this time";
  case EAI_BADFLAGS:
    return "The flags parameter had an invalid value";
  case EAI_FAIL:
    return "A non-recoverable error occurred when attempting to "
      "resolve the name";
  case EAI_FAMILY:
    return "The address family was not recognized";
  case EAI_MEMORY:
    return "Out of memory";
  case EAI_NONAME:
    return "The name does not resolve for the supplied parameters";
  case EAI_SERVICE:
    return "The service passed was not recognized for the "
      "specified socket type"
  case EAI_SOCKTYPE:
    return "The intended socket type was not recognized"
  case EAI_SYSTEM:
    return "A system error occurred";
  case EAI_OVERFLOW:
    return "An argument buffer overflowed";
  default:
    return "Unknown error";

/* define this now as this is a private implementation of said function */
#define HAVE_GAI_STRERROR
}
#endif


/*
 * resolver_error() calls failf() with the appropriate message after a resolve
 * error
 */

static void resolver_error(struct connectdata *conn, const char *host_or_proxy)
{
  failf(conn->data, "Could not resolve %s: %s; %s", host_or_proxy,
        conn->async.hostname,
#ifdef HAVE_GAI_STRERROR
        /* NetWare doesn't have gai_strerror and on Windows it isn't deemed
           thread-safe */
        gai_strerror(conn->async.status)
#else
        Curl_strerror(conn, conn->async.status)
#endif
    );
}

/*
 * 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
 *
 * This is the version for resolves-in-a-thread.
 */
CURLcode Curl_resolver_wait_resolv(struct connectdata *conn,
                                   struct Curl_dns_entry **entry)
{
  struct thread_data   *td = (struct thread_data*) conn->async.os_specific;
  CURLcode rc = CURLE_OK;

  DEBUGASSERT(conn && td);

  /* wait for the thread to resolve the name */
  if(Curl_thread_join(&td->thread_hnd))
    rc = getaddrinfo_complete(conn);
  else
    DEBUGASSERT(0);

  conn->async.done = TRUE;

  if(entry)
    *entry = conn->async.dns;

  if(!conn->async.dns) {
    /* a name was not resolved */
    if(conn->bits.httpproxy) {
      resolver_error(conn, "proxy");
      rc = CURLE_COULDNT_RESOLVE_PROXY;
    }
    else {
      resolver_error(conn, "host");
      rc = CURLE_COULDNT_RESOLVE_HOST;
    }
  }

  destroy_async_data(&conn->async);

  if(!conn->async.dns)
    conn->bits.close = TRUE;

  return (rc);
}

/*
 * 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 connectdata *conn,
                                   struct Curl_dns_entry **entry)
{
  struct SessionHandle *data = conn->data;
  struct thread_data   *td = (struct thread_data*) conn->async.os_specific;
  int done = 0;

  *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(conn);
    destroy_async_data(&conn->async);

    if(!conn->async.dns) {
      resolver_error(conn, "host");
      return CURLE_COULDNT_RESOLVE_HOST;
    }
    *entry = conn->async.dns;
  }
  else {
    /* poll for name lookup done with exponential backoff up to 250ms */
    int elapsed = Curl_tvdiff(Curl_tvnow(), 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(conn->data, td->poll_interval);
  }

  return CURLE_OK;
}

int Curl_resolver_getsock(struct connectdata *conn,
                          curl_socket_t *socks,
                          int numsocks)
{
  const struct thread_data *td =
    (const struct thread_data *) conn->async.os_specific;

  if(td && td->dummy_sock != CURL_SOCKET_BAD) {
    if(numsocks) {
      /* return one socket waiting for readable, even though this is just
         a dummy */
      socks[0] = td->dummy_sock;
      return GETSOCK_READSOCK(0);
    }
  }
  return 0;
}

#ifndef HAVE_GETADDRINFO
/*
 * Curl_getaddrinfo() - for platforms without getaddrinfo
 */
Curl_addrinfo *Curl_resolver_getaddrinfo(struct connectdata *conn,
                                         const char *hostname,
                                         int port,
                                         int *waitp)
{
  struct in_addr in;

  *waitp = 0; /* default to synchronous response */

  if(Curl_inet_pton(AF_INET, hostname, &in) > 0)
    /* This is a dotted IP address 123.123.123.123-style */
    return Curl_ip2addr(AF_INET, &in, hostname, port);

  /* fire up a new resolver thread! */
  if(init_resolve_thread(conn, hostname, port, NULL)) {
    *waitp = 1; /* expect asynchronous response */
    return NULL;
  }

  /* fall-back to blocking version */
  return Curl_ipv4_resolve_r(hostname, port);
}

#else /* !HAVE_GETADDRINFO */

/*
 * Curl_resolver_getaddrinfo() - for getaddrinfo
 */
Curl_addrinfo *Curl_resolver_getaddrinfo(struct connectdata *conn,
                                         const char *hostname,
                                         int port,
                                         int *waitp)
{
  struct addrinfo hints;
  Curl_addrinfo *res;
  int error;
  char sbuf[NI_MAXSERV];
  int pf = PF_INET;

  *waitp = 0; /* default to synchronous response */

#ifndef CURLRES_IPV4
  /*
   * Check if a limited name resolve has been requested.
   */
  switch(conn->ip_version) {
  case CURL_IPRESOLVE_V4:
    pf = PF_INET;
    break;
  case CURL_IPRESOLVE_V6:
    pf = PF_INET6;
    break;
  default:
    pf = PF_UNSPEC;
    break;
  }

  if((pf != PF_INET) && !Curl_ipv6works())
    /* the stack seems to be a non-ipv6 one */
    pf = PF_INET;

#endif /* !CURLRES_IPV4 */

  memset(&hints, 0, sizeof(hints));
  hints.ai_family = pf;
  hints.ai_socktype = conn->socktype;

  snprintf(sbuf, sizeof(sbuf), "%d", port);

  /* fire up a new resolver thread! */
  if(init_resolve_thread(conn, hostname, port, &hints)) {
    *waitp = 1; /* expect asynchronous response */
    return NULL;
  }

  /* fall-back to blocking version */
  infof(conn->data, "init_resolve_thread() failed for %s; %s\n",
        hostname, Curl_strerror(conn, ERRNO));

  error = Curl_getaddrinfo_ex(hostname, sbuf, &hints, &res);
  if(error) {
    infof(conn->data, "getaddrinfo() failed for %s:%d; %s\n",
          hostname, port, Curl_strerror(conn, SOCKERRNO));
    return NULL;
  }
  return res;
}

#endif /* !HAVE_GETADDRINFO */

#endif /* CURLRES_THREADED */