gio/gresolver.c

   1 /* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
   2
   3 /* GIO - GLib Input, Output and Streaming Library
   4  *
   5  * Copyright (C) 2008 Red Hat, Inc.
   6  *
   7  * This library is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2 of the License, or (at your option) any later version.
  11  *
  12  * This library is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General
  18  * Public License along with this library; if not, write to the
  19  * Free Software Foundation, Inc., 59 Temple Place, Suite 330,
  20  * Boston, MA 02111-1307, USA.
  21  */
  22
  23 #include "config.h"
  24 #include <glib.h>
  25 #include "glibintl.h"
  26
  27 #include "gresolver.h"
  28 #include "gnetworkingprivate.h"
  29 #include "gasyncresult.h"
  30 #include "ginetaddress.h"
  31 #include "ginetsocketaddress.h"
  32 #include "gsimpleasyncresult.h"
  33 #include "gsrvtarget.h"
  34 #include "gthreadedresolver.h"
  35
  36 #ifdef G_OS_UNIX
  37 #include <sys/stat.h>
  38 #endif
  39
  40 #include <stdlib.h>
  41
  42
  43 /**
  44  * SECTION:gresolver
  45  * @short_description: Asynchronous and cancellable DNS resolver
  46  * @include: gio/gio.h
  47  *
  48  * #GResolver provides cancellable synchronous and asynchronous DNS
  49  * resolution, for hostnames (g_resolver_lookup_by_address(),
  50  * g_resolver_lookup_by_name() and their async variants) and SRV
  51  * (service) records (g_resolver_lookup_service()).
  52  *
  53  * #GNetworkAddress and #GNetworkService provide wrappers around
  54  * #GResolver functionality that also implement #GSocketConnectable,
  55  * making it easy to connect to a remote host/service.
  56  */
  57
  58 enum {
  59   RELOAD,
  60   LAST_SIGNAL
  61 };
  62
  63 static guint signals[LAST_SIGNAL] = { 0 };
  64
  65 struct _GResolverPrivate {
  66 #ifdef G_OS_UNIX
  67   time_t resolv_conf_timestamp;
  68 #else
  69   int dummy;
  70 #endif
  71 };
  72
  73 /**
  74  * GResolver:
  75  *
  76  * The object that handles DNS resolution. Use g_resolver_get_default()
  77  * to get the default resolver.
  78  */
  79 G_DEFINE_TYPE (GResolver, g_resolver, G_TYPE_OBJECT)
  80
  81 static void
  82 g_resolver_class_init (GResolverClass *resolver_class)
  83 {
  84   volatile GType type;
  85
  86   g_type_class_add_private (resolver_class, sizeof (GResolverPrivate));
  87
  88   /* Make sure _g_networking_init() has been called */
  89   type = g_inet_address_get_type ();
  90   (type); /* To avoid -Wunused-but-set-variable */
  91
  92   /* Initialize _g_resolver_addrinfo_hints */
  93 #ifdef AI_ADDRCONFIG
  94   _g_resolver_addrinfo_hints.ai_flags |= AI_ADDRCONFIG;
  95 #endif
  96   /* These two don't actually matter, they just get copied into the
  97    * returned addrinfo structures (and then we ignore them). But if
  98    * we leave them unset, we'll get back duplicate answers.
  99    */
 100   _g_resolver_addrinfo_hints.ai_socktype = SOCK_STREAM;
 101   _g_resolver_addrinfo_hints.ai_protocol = IPPROTO_TCP;
 102
 103   /**
 104    * GResolver::reload:
 105    * @resolver: a #GResolver
 106    *
 107    * Emitted when the resolver notices that the system resolver
 108    * configuration has changed.
 109    **/
 110   signals[RELOAD] =
 111     g_signal_new (I_("reload"),
 112                   G_TYPE_RESOLVER,
 113                   G_SIGNAL_RUN_LAST,
 114                   G_STRUCT_OFFSET (GResolverClass, reload),
 115                   NULL, NULL,
 116                   g_cclosure_marshal_VOID__VOID,
 117                   G_TYPE_NONE, 0);
 118 }
 119
 120 static void
 121 g_resolver_init (GResolver *resolver)
 122 {
 123 #ifdef G_OS_UNIX
 124   struct stat st;
 125 #endif
 126
 127   resolver->priv = G_TYPE_INSTANCE_GET_PRIVATE (resolver, G_TYPE_RESOLVER, GResolverPrivate);
 128
 129 #ifdef G_OS_UNIX
 130   if (stat (_PATH_RESCONF, &st) == 0)
 131     resolver->priv->resolv_conf_timestamp = st.st_mtime;
 132 #endif
 133 }
 134
 135 static GResolver *default_resolver;
 136
 137 /**
 138  * g_resolver_get_default:
 139  *
 140  * Gets the default #GResolver. You should unref it when you are done
 141  * with it. #GResolver may use its reference count as a hint about how
 142  * many threads/processes, etc it should allocate for concurrent DNS
 143  * resolutions.
 144  *
 145  * Return value: (transfer full): the default #GResolver.
 146  *
 147  * Since: 2.22
 148  */
 149 GResolver *
 150 g_resolver_get_default (void)
 151 {
 152   if (!default_resolver)
 153     default_resolver = g_object_new (G_TYPE_THREADED_RESOLVER, NULL);
 154
 155   return g_object_ref (default_resolver);
 156 }
 157
 158 /**
 159  * g_resolver_set_default:
 160  * @resolver: the new default #GResolver
 161  *
 162  * Sets @resolver to be the application's default resolver (reffing
 163  * @resolver, and unreffing the previous default resolver, if any).
 164  * Future calls to g_resolver_get_default() will return this resolver.
 165  *
 166  * This can be used if an application wants to perform any sort of DNS
 167  * caching or "pinning"; it can implement its own #GResolver that
 168  * calls the original default resolver for DNS operations, and
 169  * implements its own cache policies on top of that, and then set
 170  * itself as the default resolver for all later code to use.
 171  *
 172  * Since: 2.22
 173  */
 174 void
 175 g_resolver_set_default (GResolver *resolver)
 176 {
 177   if (default_resolver)
 178     g_object_unref (default_resolver);
 179   default_resolver = g_object_ref (resolver);
 180 }
 181
 182
 183 static void
 184 g_resolver_maybe_reload (GResolver *resolver)
 185 {
 186 #ifdef G_OS_UNIX
 187   struct stat st;
 188
 189   if (stat (_PATH_RESCONF, &st) == 0)
 190     {
 191       if (st.st_mtime != resolver->priv->resolv_conf_timestamp)
 192         {
 193           resolver->priv->resolv_conf_timestamp = st.st_mtime;
 194           res_init ();
 195           g_signal_emit (resolver, signals[RELOAD], 0);
 196         }
 197     }
 198 #endif
 199 }
 200
 201 /* filter out duplicates, cf. https://bugzilla.gnome.org/show_bug.cgi?id=631379 */
 202 static void
 203 remove_duplicates (GList *addrs)
 204 {
 205   GList *l;
 206   GList *ll;
 207   GList *lll;
 208
 209   /* TODO: if this is too slow (it's O(n^2) but n is typically really
 210    * small), we can do something more clever but note that we must not
 211    * change the order of elements...
 212    */
 213   for (l = addrs; l != NULL; l = l->next)
 214     {
 215       GInetAddress *address = G_INET_ADDRESS (l->data);
 216       for (ll = l->next; ll != NULL; ll = lll)
 217         {
 218           GInetAddress *other_address = G_INET_ADDRESS (ll->data);
 219           lll = ll->next;
 220           if (g_inet_address_equal (address, other_address))
 221             {
 222               g_object_unref (other_address);
 223               /* we never return the first element */
 224               g_warn_if_fail (g_list_delete_link (addrs, ll) == addrs);
 225             }
 226         }
 227     }
 228 }
 229
 230
 231 /**
 232  * g_resolver_lookup_by_name:
 233  * @resolver: a #GResolver
 234  * @hostname: the hostname to look up
 235  * @cancellable: (allow-none): a #GCancellable, or %NULL
 236  * @error: return location for a #GError, or %NULL
 237  *
 238  * Synchronously resolves @hostname to determine its associated IP
 239  * address(es). @hostname may be an ASCII-only or UTF-8 hostname, or
 240  * the textual form of an IP address (in which case this just becomes
 241  * a wrapper around g_inet_address_new_from_string()).
 242  *
 243  * On success, g_resolver_lookup_by_name() will return a #GList of
 244  * #GInetAddress, sorted in order of preference and guaranteed to not
 245  * contain duplicates. That is, if using the result to connect to
 246  * @hostname, you should attempt to connect to the first address
 247  * first, then the second if the first fails, etc. If you are using
 248  * the result to listen on a socket, it is appropriate to add each
 249  * result using e.g. g_socket_listener_add_address().
 250  *
 251  * If the DNS resolution fails, @error (if non-%NULL) will be set to a
 252  * value from #GResolverError.
 253  *
 254  * If @cancellable is non-%NULL, it can be used to cancel the
 255  * operation, in which case @error (if non-%NULL) will be set to
 256  * %G_IO_ERROR_CANCELLED.
 257  *
 258  * If you are planning to connect to a socket on the resolved IP
 259  * address, it may be easier to create a #GNetworkAddress and use its
 260  * #GSocketConnectable interface.
 261  *
 262  * Return value: (element-type GInetAddress) (transfer full): a #GList
 263  * of #GInetAddress, or %NULL on error. You
 264  * must unref each of the addresses and free the list when you are
 265  * done with it. (You can use g_resolver_free_addresses() to do this.)
 266  *
 267  * Since: 2.22
 268  */
 269 GList *
 270 g_resolver_lookup_by_name (GResolver     *resolver,
 271                            const gchar   *hostname,
 272                            GCancellable  *cancellable,
 273                            GError       **error)
 274 {
 275   GInetAddress *addr;
 276   GList *addrs;
 277   gchar *ascii_hostname = NULL;
 278
 279   g_return_val_if_fail (G_IS_RESOLVER (resolver), NULL);
 280   g_return_val_if_fail (hostname != NULL, NULL);
 281
 282   /* Check if @hostname is just an IP address */
 283   addr = g_inet_address_new_from_string (hostname);
 284   if (addr)
 285     return g_list_append (NULL, addr);
 286
 287   if (g_hostname_is_non_ascii (hostname))
 288     hostname = ascii_hostname = g_hostname_to_ascii (hostname);
 289
 290   g_resolver_maybe_reload (resolver);
 291   addrs = G_RESOLVER_GET_CLASS (resolver)->
 292     lookup_by_name (resolver, hostname, cancellable, error);
 293
 294   remove_duplicates (addrs);
 295
 296   g_free (ascii_hostname);
 297   return addrs;
 298 }
 299
 300 /**
 301  * g_resolver_lookup_by_name_async:
 302  * @resolver: a #GResolver
 303  * @hostname: the hostname to look up the address of
 304  * @cancellable: (allow-none): a #GCancellable, or %NULL
 305  * @callback: (scope async): callback to call after resolution completes
 306  * @user_data: (closure): data for @callback
 307  *
 308  * Begins asynchronously resolving @hostname to determine its
 309  * associated IP address(es), and eventually calls @callback, which
 310  * must call g_resolver_lookup_by_name_finish() to get the result.
 311  * See g_resolver_lookup_by_name() for more details.
 312  *
 313  * Since: 2.22
 314  */
 315 void
 316 g_resolver_lookup_by_name_async (GResolver           *resolver,
 317                                  const gchar         *hostname,
 318                                  GCancellable        *cancellable,
 319                                  GAsyncReadyCallback  callback,
 320                                  gpointer             user_data)
 321 {
 322   GInetAddress *addr;
 323   gchar *ascii_hostname = NULL;
 324
 325   g_return_if_fail (G_IS_RESOLVER (resolver));
 326   g_return_if_fail (hostname != NULL);
 327
 328   /* Check if @hostname is just an IP address */
 329   addr = g_inet_address_new_from_string (hostname);
 330   if (addr)
 331     {
 332       GSimpleAsyncResult *simple;
 333
 334       simple = g_simple_async_result_new (G_OBJECT (resolver),
 335                                           callback, user_data,
 336                                           g_resolver_lookup_by_name_async);
 337
 338       g_simple_async_result_set_op_res_gpointer (simple, addr, g_object_unref);
 339       g_simple_async_result_complete_in_idle (simple);
 340       g_object_unref (simple);
 341       return;
 342     }
 343
 344   if (g_hostname_is_non_ascii (hostname))
 345     hostname = ascii_hostname = g_hostname_to_ascii (hostname);
 346
 347   g_resolver_maybe_reload (resolver);
 348   G_RESOLVER_GET_CLASS (resolver)->
 349     lookup_by_name_async (resolver, hostname, cancellable, callback, user_data);
 350
 351   g_free (ascii_hostname);
 352 }
 353
 354 /**
 355  * g_resolver_lookup_by_name_finish:
 356  * @resolver: a #GResolver
 357  * @result: the result passed to your #GAsyncReadyCallback
 358  * @error: return location for a #GError, or %NULL
 359  *
 360  * Retrieves the result of a call to
 361  * g_resolver_lookup_by_name_async().
 362  *
 363  * If the DNS resolution failed, @error (if non-%NULL) will be set to
 364  * a value from #GResolverError. If the operation was cancelled,
 365  * @error will be set to %G_IO_ERROR_CANCELLED.
 366  *
 367  * Return value: (element-type GInetAddress) (transfer full): a #GList
 368  * of #GInetAddress, or %NULL on error. See g_resolver_lookup_by_name()
 369  * for more details.
 370  *
 371  * Since: 2.22
 372  */
 373 GList *
 374 g_resolver_lookup_by_name_finish (GResolver     *resolver,
 375                                   GAsyncResult  *result,
 376                                   GError       **error)
 377 {
 378   GList *addrs;
 379
 380   g_return_val_if_fail (G_IS_RESOLVER (resolver), NULL);
 381
 382   if (G_IS_SIMPLE_ASYNC_RESULT (result))
 383     {
 384       GSimpleAsyncResult *simple = G_SIMPLE_ASYNC_RESULT (result);
 385
 386       if (g_simple_async_result_propagate_error (simple, error))
 387         return NULL;
 388
 389       /* Handle the stringified-IP-addr case */
 390       if (g_simple_async_result_get_source_tag (simple) == g_resolver_lookup_by_name_async)
 391         {
 392           GInetAddress *addr;
 393
 394           addr = g_simple_async_result_get_op_res_gpointer (simple);
 395           return g_list_append (NULL, g_object_ref (addr));
 396         }
 397     }
 398
 399   addrs = G_RESOLVER_GET_CLASS (resolver)->
 400     lookup_by_name_finish (resolver, result, error);
 401
 402   remove_duplicates (addrs);
 403
 404   return addrs;
 405 }
 406
 407 /**
 408  * g_resolver_free_addresses: (skip)
 409  * @addresses: a #GList of #GInetAddress
 410  *
 411  * Frees @addresses (which should be the return value from
 412  * g_resolver_lookup_by_name() or g_resolver_lookup_by_name_finish()).
 413  * (This is a convenience method; you can also simply free the results
 414  * by hand.)
 415  *
 416  * Since: 2.22
 417  */
 418 void
 419 g_resolver_free_addresses (GList *addresses)
 420 {
 421   GList *a;
 422
 423   for (a = addresses; a; a = a->next)
 424     g_object_unref (a->data);
 425   g_list_free (addresses);
 426 }
 427
 428 /**
 429  * g_resolver_lookup_by_address:
 430  * @resolver: a #GResolver
 431  * @address: the address to reverse-resolve
 432  * @cancellable: (allow-none): a #GCancellable, or %NULL
 433  * @error: return location for a #GError, or %NULL
 434  *
 435  * Synchronously reverse-resolves @address to determine its
 436  * associated hostname.
 437  *
 438  * If the DNS resolution fails, @error (if non-%NULL) will be set to
 439  * a value from #GResolverError.
 440  *
 441  * If @cancellable is non-%NULL, it can be used to cancel the
 442  * operation, in which case @error (if non-%NULL) will be set to
 443  * %G_IO_ERROR_CANCELLED.
 444  *
 445  * Return value: a hostname (either ASCII-only, or in ASCII-encoded
 446  *     form), or %NULL on error.
 447  *
 448  * Since: 2.22
 449  */
 450 gchar *
 451 g_resolver_lookup_by_address (GResolver     *resolver,
 452                               GInetAddress  *address,
 453                               GCancellable  *cancellable,
 454                               GError       **error)
 455 {
 456   g_return_val_if_fail (G_IS_RESOLVER (resolver), NULL);
 457   g_return_val_if_fail (G_IS_INET_ADDRESS (address), NULL);
 458
 459   g_resolver_maybe_reload (resolver);
 460   return G_RESOLVER_GET_CLASS (resolver)->
 461     lookup_by_address (resolver, address, cancellable, error);
 462 }
 463
 464 /**
 465  * g_resolver_lookup_by_address_async:
 466  * @resolver: a #GResolver
 467  * @address: the address to reverse-resolve
 468  * @cancellable: (allow-none): a #GCancellable, or %NULL
 469  * @callback: (scope async): callback to call after resolution completes
 470  * @user_data: (closure): data for @callback
 471  *
 472  * Begins asynchronously reverse-resolving @address to determine its
 473  * associated hostname, and eventually calls @callback, which must
 474  * call g_resolver_lookup_by_address_finish() to get the final result.
 475  *
 476  * Since: 2.22
 477  */
 478 void
 479 g_resolver_lookup_by_address_async (GResolver           *resolver,
 480                                     GInetAddress        *address,
 481                                     GCancellable        *cancellable,
 482                                     GAsyncReadyCallback  callback,
 483                                     gpointer             user_data)
 484 {
 485   g_return_if_fail (G_IS_RESOLVER (resolver));
 486   g_return_if_fail (G_IS_INET_ADDRESS (address));
 487
 488   g_resolver_maybe_reload (resolver);
 489   G_RESOLVER_GET_CLASS (resolver)->
 490     lookup_by_address_async (resolver, address, cancellable, callback, user_data);
 491 }
 492
 493 /**
 494  * g_resolver_lookup_by_address_finish:
 495  * @resolver: a #GResolver
 496  * @result: the result passed to your #GAsyncReadyCallback
 497  * @error: return location for a #GError, or %NULL
 498  *
 499  * Retrieves the result of a previous call to
 500  * g_resolver_lookup_by_address_async().
 501  *
 502  * If the DNS resolution failed, @error (if non-%NULL) will be set to
 503  * a value from #GResolverError. If the operation was cancelled,
 504  * @error will be set to %G_IO_ERROR_CANCELLED.
 505  *
 506  * Return value: a hostname (either ASCII-only, or in ASCII-encoded
 507  * form), or %NULL on error.
 508  *
 509  * Since: 2.22
 510  */
 511 gchar *
 512 g_resolver_lookup_by_address_finish (GResolver     *resolver,
 513                                      GAsyncResult  *result,
 514                                      GError       **error)
 515 {
 516   g_return_val_if_fail (G_IS_RESOLVER (resolver), NULL);
 517
 518   if (G_IS_SIMPLE_ASYNC_RESULT (result))
 519     {
 520       GSimpleAsyncResult *simple = G_SIMPLE_ASYNC_RESULT (result);
 521
 522       if (g_simple_async_result_propagate_error (simple, error))
 523         return NULL;
 524     }
 525
 526   return G_RESOLVER_GET_CLASS (resolver)->
 527     lookup_by_address_finish (resolver, result, error);
 528 }
 529
 530 static gchar *
 531 g_resolver_get_service_rrname (const char *service,
 532                                const char *protocol,
 533                                const char *domain)
 534 {
 535   gchar *rrname, *ascii_domain = NULL;
 536
 537   if (g_hostname_is_non_ascii (domain))
 538     domain = ascii_domain = g_hostname_to_ascii (domain);
 539
 540   rrname = g_strdup_printf ("_%s._%s.%s", service, protocol, domain);
 541
 542   g_free (ascii_domain);
 543   return rrname;
 544 }
 545
 546 /**
 547  * g_resolver_lookup_service:
 548  * @resolver: a #GResolver
 549  * @service: the service type to look up (eg, "ldap")
 550  * @protocol: the networking protocol to use for @service (eg, "tcp")
 551  * @domain: the DNS domain to look up the service in
 552  * @cancellable: (allow-none): a #GCancellable, or %NULL
 553  * @error: return location for a #GError, or %NULL
 554  *
 555  * Synchronously performs a DNS SRV lookup for the given @service and
 556  * @protocol in the given @domain and returns an array of #GSrvTarget.
 557  * @domain may be an ASCII-only or UTF-8 hostname. Note also that the
 558  * @service and @protocol arguments <emphasis>do not</emphasis>
 559  * include the leading underscore that appears in the actual DNS
 560  * entry.
 561  *
 562  * On success, g_resolver_lookup_service() will return a #GList of
 563  * #GSrvTarget, sorted in order of preference. (That is, you should
 564  * attempt to connect to the first target first, then the second if
 565  * the first fails, etc.)
 566  *
 567  * If the DNS resolution fails, @error (if non-%NULL) will be set to
 568  * a value from #GResolverError.
 569  *
 570  * If @cancellable is non-%NULL, it can be used to cancel the
 571  * operation, in which case @error (if non-%NULL) will be set to
 572  * %G_IO_ERROR_CANCELLED.
 573  *
 574  * If you are planning to connect to the service, it is usually easier
 575  * to create a #GNetworkService and use its #GSocketConnectable
 576  * interface.
 577  *
 578  * Return value: (element-type GSrvTarget) (transfer full): a #GList of #GSrvTarget,
 579  * or %NULL on error. You must free each of the targets and the list when you are
 580  * done with it. (You can use g_resolver_free_targets() to do this.)
 581  *
 582  * Since: 2.22
 583  */
 584 GList *
 585 g_resolver_lookup_service (GResolver     *resolver,
 586                            const gchar   *service,
 587                            const gchar   *protocol,
 588                            const gchar   *domain,
 589                            GCancellable  *cancellable,
 590                            GError       **error)
 591 {
 592   GList *targets;
 593   gchar *rrname;
 594
 595   g_return_val_if_fail (G_IS_RESOLVER (resolver), NULL);
 596   g_return_val_if_fail (service != NULL, NULL);
 597   g_return_val_if_fail (protocol != NULL, NULL);
 598   g_return_val_if_fail (domain != NULL, NULL);
 599
 600   rrname = g_resolver_get_service_rrname (service, protocol, domain);
 601
 602   g_resolver_maybe_reload (resolver);
 603   targets = G_RESOLVER_GET_CLASS (resolver)->
 604     lookup_service (resolver, rrname, cancellable, error);
 605
 606   g_free (rrname);
 607   return targets;
 608 }
 609
 610 /**
 611  * g_resolver_lookup_service_async:
 612  * @resolver: a #GResolver
 613  * @service: the service type to look up (eg, "ldap")
 614  * @protocol: the networking protocol to use for @service (eg, "tcp")
 615  * @domain: the DNS domain to look up the service in
 616  * @cancellable: (allow-none): a #GCancellable, or %NULL
 617  * @callback: (scope async): callback to call after resolution completes
 618  * @user_data: (closure): data for @callback
 619  *
 620  * Begins asynchronously performing a DNS SRV lookup for the given
 621  * @service and @protocol in the given @domain, and eventually calls
 622  * @callback, which must call g_resolver_lookup_service_finish() to
 623  * get the final result. See g_resolver_lookup_service() for more
 624  * details.
 625  *
 626  * Since: 2.22
 627  */
 628 void
 629 g_resolver_lookup_service_async (GResolver           *resolver,
 630                                  const gchar         *service,
 631                                  const gchar         *protocol,
 632                                  const gchar         *domain,
 633                                  GCancellable        *cancellable,
 634                                  GAsyncReadyCallback  callback,
 635                                  gpointer             user_data)
 636 {
 637   gchar *rrname;
 638
 639   g_return_if_fail (G_IS_RESOLVER (resolver));
 640   g_return_if_fail (service != NULL);
 641   g_return_if_fail (protocol != NULL);
 642   g_return_if_fail (domain != NULL);
 643
 644   rrname = g_resolver_get_service_rrname (service, protocol, domain);
 645
 646   g_resolver_maybe_reload (resolver);
 647   G_RESOLVER_GET_CLASS (resolver)->
 648     lookup_service_async (resolver, rrname, cancellable, callback, user_data);
 649
 650   g_free (rrname);
 651 }
 652
 653 /**
 654  * g_resolver_lookup_service_finish:
 655  * @resolver: a #GResolver
 656  * @result: the result passed to your #GAsyncReadyCallback
 657  * @error: return location for a #GError, or %NULL
 658  *
 659  * Retrieves the result of a previous call to
 660  * g_resolver_lookup_service_async().
 661  *
 662  * If the DNS resolution failed, @error (if non-%NULL) will be set to
 663  * a value from #GResolverError. If the operation was cancelled,
 664  * @error will be set to %G_IO_ERROR_CANCELLED.
 665  *
 666  * Return value: (element-type GSrvTarget) (transfer full): a #GList of #GSrvTarget,
 667  * or %NULL on error. See g_resolver_lookup_service() for more details.
 668  *
 669  * Since: 2.22
 670  */
 671 GList *
 672 g_resolver_lookup_service_finish (GResolver     *resolver,
 673                                   GAsyncResult  *result,
 674                                   GError       **error)
 675 {
 676   g_return_val_if_fail (G_IS_RESOLVER (resolver), NULL);
 677
 678   if (G_IS_SIMPLE_ASYNC_RESULT (result))
 679     {
 680       GSimpleAsyncResult *simple = G_SIMPLE_ASYNC_RESULT (result);
 681
 682       if (g_simple_async_result_propagate_error (simple, error))
 683         return NULL;
 684     }
 685
 686   return G_RESOLVER_GET_CLASS (resolver)->
 687     lookup_service_finish (resolver, result, error);
 688 }
 689
 690 /**
 691  * g_resolver_free_targets: (skip)
 692  * @targets: a #GList of #GSrvTarget
 693  *
 694  * Frees @targets (which should be the return value from
 695  * g_resolver_lookup_service() or g_resolver_lookup_service_finish()).
 696  * (This is a convenience method; you can also simply free the
 697  * results by hand.)
 698  *
 699  * Since: 2.22
 700  */
 701 void
 702 g_resolver_free_targets (GList *targets)
 703 {
 704   GList *t;
 705
 706   for (t = targets; t; t = t->next)
 707     g_srv_target_free (t->data);
 708   g_list_free (targets);
 709 }
 710
 711 /**
 712  * g_resolver_error_quark:
 713  *
 714  * Gets the #GResolver Error Quark.
 715  *
 716  * Return value: a #GQuark.
 717  *
 718  * Since: 2.22
 719  */
 720 GQuark
 721 g_resolver_error_quark (void)
 722 {
 723   return g_quark_from_static_string ("g-resolver-error-quark");
 724 }
 725
 726
 727 static GResolverError
 728 g_resolver_error_from_addrinfo_error (gint err)
 729 {
 730   switch (err)
 731     {
 732     case EAI_FAIL:
 733 #if defined(EAI_NODATA) && (EAI_NODATA != EAI_NONAME)
 734     case EAI_NODATA:
 735 #endif
 736     case EAI_NONAME:
 737       return G_RESOLVER_ERROR_NOT_FOUND;
 738
 739     case EAI_AGAIN:
 740       return G_RESOLVER_ERROR_TEMPORARY_FAILURE;
 741
 742     default:
 743       return G_RESOLVER_ERROR_INTERNAL;
 744     }
 745 }
 746
 747 struct addrinfo _g_resolver_addrinfo_hints;
 748
 749 /* Private method to process a getaddrinfo() response. */
 750 GList *
 751 _g_resolver_addresses_from_addrinfo (const char       *hostname,
 752                                      struct addrinfo  *res,
 753                                      gint              gai_retval,
 754                                      GError          **error)
 755 {
 756   struct addrinfo *ai;
 757   GSocketAddress *sockaddr;
 758   GInetAddress *addr;
 759   GList *addrs;
 760
 761   if (gai_retval != 0)
 762     {
 763       g_set_error (error, G_RESOLVER_ERROR,
 764                    g_resolver_error_from_addrinfo_error (gai_retval),
 765                    _("Error resolving '%s': %s"),
 766                    hostname, gai_strerror (gai_retval));
 767       return NULL;
 768     }
 769
 770   g_return_val_if_fail (res != NULL, NULL);
 771
 772   addrs = NULL;
 773   for (ai = res; ai; ai = ai->ai_next)
 774     {
 775       sockaddr = g_socket_address_new_from_native (ai->ai_addr, ai->ai_addrlen);
 776       if (!sockaddr || !G_IS_INET_SOCKET_ADDRESS (sockaddr))
 777         continue;
 778
 779       addr = g_object_ref (g_inet_socket_address_get_address ((GInetSocketAddress *)sockaddr));
 780       addrs = g_list_prepend (addrs, addr);
 781       g_object_unref (sockaddr);
 782     }
 783
 784   return g_list_reverse (addrs);
 785 }
 786
 787 /* Private method to set up a getnameinfo() request */
 788 void
 789 _g_resolver_address_to_sockaddr (GInetAddress            *address,
 790                                  struct sockaddr_storage *sa,
 791                                  gsize                   *len)
 792 {
 793   GSocketAddress *sockaddr;
 794
 795   sockaddr = g_inet_socket_address_new (address, 0);
 796   g_socket_address_to_native (sockaddr, (struct sockaddr *)sa, sizeof (*sa), NULL);
 797   *len = g_socket_address_get_native_size (sockaddr);
 798   g_object_unref (sockaddr);
 799 }
 800
 801 /* Private method to process a getnameinfo() response. */
 802 char *
 803 _g_resolver_name_from_nameinfo (GInetAddress  *address,
 804                                 const gchar   *name,
 805                                 gint           gni_retval,
 806                                 GError       **error)
 807 {
 808   if (gni_retval != 0)
 809     {
 810       gchar *phys;
 811
 812       phys = g_inet_address_to_string (address);
 813       g_set_error (error, G_RESOLVER_ERROR,
 814                    g_resolver_error_from_addrinfo_error (gni_retval),
 815                    _("Error reverse-resolving '%s': %s"),
 816                    phys ? phys : "(unknown)", gai_strerror (gni_retval));
 817       g_free (phys);
 818       return NULL;
 819     }
 820
 821   return g_strdup (name);
 822 }
 823
 824 #if defined(G_OS_UNIX)
 825 /* Private method to process a res_query response into GSrvTargets */
 826 GList *
 827 _g_resolver_targets_from_res_query (const gchar      *rrname,
 828                                     guchar           *answer,
 829                                     gint              len,
 830                                     gint              herr,
 831                                     GError          **error)
 832 {
 833   gint count;
 834   gchar namebuf[1024];
 835   guchar *end, *p;
 836   guint16 type, qclass, rdlength, priority, weight, port;
 837   guint32 ttl;
 838   HEADER *header;
 839   GSrvTarget *target;
 840   GList *targets;
 841
 842   if (len <= 0)
 843     {
 844       GResolverError errnum;
 845       const gchar *format;
 846
 847       if (len == 0 || herr == HOST_NOT_FOUND || herr == NO_DATA)
 848         {
 849           errnum = G_RESOLVER_ERROR_NOT_FOUND;
 850           format = _("No service record for '%s'");
 851         }
 852       else if (herr == TRY_AGAIN)
 853         {
 854           errnum = G_RESOLVER_ERROR_TEMPORARY_FAILURE;
 855           format = _("Temporarily unable to resolve '%s'");
 856         }
 857       else
 858         {
 859           errnum = G_RESOLVER_ERROR_INTERNAL;
 860           format = _("Error resolving '%s'");
 861         }
 862
 863       g_set_error (error, G_RESOLVER_ERROR, errnum, format, rrname);
 864       return NULL;
 865     }
 866
 867   targets = NULL;
 868
 869   header = (HEADER *)answer;
 870   p = answer + sizeof (HEADER);
 871   end = answer + len;
 872
 873   /* Skip query */
 874   count = ntohs (header->qdcount);
 875   while (count-- && p < end)
 876     {
 877       p += dn_expand (answer, end, p, namebuf, sizeof (namebuf));
 878       p += 4;
 879     }
 880
 881   /* Read answers */
 882   count = ntohs (header->ancount);
 883   while (count-- && p < end)
 884     {
 885       p += dn_expand (answer, end, p, namebuf, sizeof (namebuf));
 886       GETSHORT (type, p);
 887       GETSHORT (qclass, p);
 888       GETLONG  (ttl, p);
 889       ttl = ttl; /* To avoid -Wunused-but-set-variable */
 890       GETSHORT (rdlength, p);
 891
 892       if (type != T_SRV || qclass != C_IN)
 893         {
 894           p += rdlength;
 895           continue;
 896         }
 897
 898       GETSHORT (priority, p);
 899       GETSHORT (weight, p);
 900       GETSHORT (port, p);
 901       p += dn_expand (answer, end, p, namebuf, sizeof (namebuf));
 902
 903       target = g_srv_target_new (namebuf, port, priority, weight);
 904       targets = g_list_prepend (targets, target);
 905     }
 906
 907   return g_srv_target_list_sort (targets);
 908 }
 909 #elif defined(G_OS_WIN32)
 910 /* Private method to process a DnsQuery response into GSrvTargets */
 911 GList *
 912 _g_resolver_targets_from_DnsQuery (const gchar  *rrname,
 913                                    DNS_STATUS    status,
 914                                    DNS_RECORD   *results,
 915                                    GError      **error)
 916 {
 917   DNS_RECORD *rec;
 918   GSrvTarget *target;
 919   GList *targets;
 920
 921   if (status != ERROR_SUCCESS)
 922     {
 923       GResolverError errnum;
 924       const gchar *format;
 925
 926       if (status == DNS_ERROR_RCODE_NAME_ERROR)
 927         {
 928           errnum = G_RESOLVER_ERROR_NOT_FOUND;
 929           format = _("No service record for '%s'");
 930         }
 931       else if (status == DNS_ERROR_RCODE_SERVER_FAILURE)
 932         {
 933           errnum = G_RESOLVER_ERROR_TEMPORARY_FAILURE;
 934           format = _("Temporarily unable to resolve '%s'");
 935         }
 936       else
 937         {
 938           errnum = G_RESOLVER_ERROR_INTERNAL;
 939           format = _("Error resolving '%s'");
 940         }
 941
 942       g_set_error (error, G_RESOLVER_ERROR, errnum, format, rrname);
 943       return NULL;
 944     }
 945
 946   targets = NULL;
 947   for (rec = results; rec; rec = rec->pNext)
 948     {
 949       if (rec->wType != DNS_TYPE_SRV)
 950         continue;
 951
 952       target = g_srv_target_new (rec->Data.SRV.pNameTarget,
 953                                  rec->Data.SRV.wPort,
 954                                  rec->Data.SRV.wPriority,
 955                                  rec->Data.SRV.wWeight);
 956       targets = g_list_prepend (targets, target);
 957     }
 958
 959   return g_srv_target_list_sort (targets);
 960 }
 961
 962 #endif