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
  35 #ifdef G_OS_UNIX
  36 #include "gunixresolver.h"
  37 #include <sys/stat.h>
  38 #endif
  39 #ifdef G_OS_WIN32
  40 #include "gwin32resolver.h"
  41 #endif
  42
  43 #include <stdlib.h>
  44
  45
  46 /**
  47  * SECTION:gresolver
  48  * @short_description: Asynchronous and cancellable DNS resolver
  49  * @include: gio/gio.h
  50  *
  51  * #GResolver provides cancellable synchronous and asynchronous DNS
  52  * resolution, for hostnames (g_resolver_lookup_by_address(),
  53  * g_resolver_lookup_by_name() and their async variants) and SRV
  54  * (service) records (g_resolver_lookup_service()).
  55  *
  56  * #GNetworkAddress and #GNetworkService provide wrappers around
  57  * #GResolver functionality that also implement #GSocketConnectable,
  58  * making it easy to connect to a remote host/service.
  59  */
  60
  61 enum {
  62   RELOAD,
  63   LAST_SIGNAL
  64 };
  65
  66 static guint signals[LAST_SIGNAL] = { 0 };
  67
  68 struct _GResolverPrivate {
  69 #ifdef G_OS_UNIX
  70   time_t resolv_conf_timestamp;
  71 #else
  72   int dummy;
  73 #endif
  74 };
  75
  76 /**
  77  * GResolver:
  78  *
  79  * The object that handles DNS resolution. Use g_resolver_get_default()
  80  * to get the default resolver.
  81  */
  82 G_DEFINE_TYPE (GResolver, g_resolver, G_TYPE_OBJECT)
  83
  84 static void
  85 g_resolver_class_init (GResolverClass *resolver_class)
  86 {
  87   volatile GType type;
  88
  89   g_type_class_add_private (resolver_class, sizeof (GResolverPrivate));
  90
  91   /* Make sure _g_networking_init() has been called */
  92   type = g_inet_address_get_type ();
  93   (type); /* To avoid -Wunused-but-set-variable */
  94
  95   /* Initialize _g_resolver_addrinfo_hints */
  96 #ifdef AI_ADDRCONFIG
  97   _g_resolver_addrinfo_hints.ai_flags |= AI_ADDRCONFIG;
  98 #endif
  99   /* These two don't actually matter, they just get copied into the
 100    * returned addrinfo structures (and then we ignore them). But if
 101    * we leave them unset, we'll get back duplicate answers.
 102    */
 103   _g_resolver_addrinfo_hints.ai_socktype = SOCK_STREAM;
 104   _g_resolver_addrinfo_hints.ai_protocol = IPPROTO_TCP;
 105
 106   /**
 107    * GResolver::reload:
 108    * @resolver: a #GResolver
 109    *
 110    * Emitted when the resolver notices that the system resolver
 111    * configuration has changed.
 112    **/
 113   signals[RELOAD] =
 114     g_signal_new (I_("reload"),
 115                   G_TYPE_RESOLVER,
 116                   G_SIGNAL_RUN_LAST,
 117                   G_STRUCT_OFFSET (GResolverClass, reload),
 118                   NULL, NULL,
 119                   g_cclosure_marshal_VOID__VOID,
 120                   G_TYPE_NONE, 0);
 121 }
 122
 123 static void
 124 g_resolver_init (GResolver *resolver)
 125 {
 126 #ifdef G_OS_UNIX
 127   struct stat st;
 128 #endif
 129
 130   resolver->priv = G_TYPE_INSTANCE_GET_PRIVATE (resolver, G_TYPE_RESOLVER, GResolverPrivate);
 131
 132 #ifdef G_OS_UNIX
 133   if (stat (_PATH_RESCONF, &st) == 0)
 134     resolver->priv->resolv_conf_timestamp = st.st_mtime;
 135 #endif
 136 }
 137
 138 static GResolver *default_resolver;
 139
 140 /**
 141  * g_resolver_get_default:
 142  *
 143  * Gets the default #GResolver. You should unref it when you are done
 144  * with it. #GResolver may use its reference count as a hint about how
 145  * many threads/processes, etc it should allocate for concurrent DNS
 146  * resolutions.
 147  *
 148  * Return value: (transfer full): the default #GResolver.
 149  *
 150  * Since: 2.22
 151  */
 152 GResolver *
 153 g_resolver_get_default (void)
 154 {
 155   if (!default_resolver)
 156     {
 157       if (g_thread_supported ())
 158         default_resolver = g_object_new (G_TYPE_THREADED_RESOLVER, NULL);
 159       else
 160         {
 161 #if defined(G_OS_UNIX)
 162           default_resolver = g_object_new (G_TYPE_UNIX_RESOLVER, NULL);
 163 #elif defined(G_OS_WIN32)
 164           default_resolver = g_object_new (G_TYPE_WIN32_RESOLVER, NULL);
 165 #endif
 166         }
 167     }
 168
 169   return g_object_ref (default_resolver);
 170 }
 171
 172 /**
 173  * g_resolver_set_default:
 174  * @resolver: the new default #GResolver
 175  *
 176  * Sets @resolver to be the application's default resolver (reffing
 177  * @resolver, and unreffing the previous default resolver, if any).
 178  * Future calls to g_resolver_get_default() will return this resolver.
 179  *
 180  * This can be used if an application wants to perform any sort of DNS
 181  * caching or "pinning"; it can implement its own #GResolver that
 182  * calls the original default resolver for DNS operations, and
 183  * implements its own cache policies on top of that, and then set
 184  * itself as the default resolver for all later code to use.
 185  *
 186  * Since: 2.22
 187  */
 188 void
 189 g_resolver_set_default (GResolver *resolver)
 190 {
 191   if (default_resolver)
 192     g_object_unref (default_resolver);
 193   default_resolver = g_object_ref (resolver);
 194 }
 195
 196
 197 static void
 198 g_resolver_maybe_reload (GResolver *resolver)
 199 {
 200 #ifdef G_OS_UNIX
 201   struct stat st;
 202
 203   if (stat (_PATH_RESCONF, &st) == 0)
 204     {
 205       if (st.st_mtime != resolver->priv->resolv_conf_timestamp)
 206         {
 207           resolver->priv->resolv_conf_timestamp = st.st_mtime;
 208           res_init ();
 209           g_signal_emit (resolver, signals[RELOAD], 0);
 210         }
 211     }
 212 #endif
 213 }
 214
 215 /**
 216  * g_resolver_lookup_by_name:
 217  * @resolver: a #GResolver
 218  * @hostname: the hostname to look up
 219  * @cancellable: (allow-none): a #GCancellable, or %NULL
 220  * @error: return location for a #GError, or %NULL
 221  *
 222  * Synchronously resolves @hostname to determine its associated IP
 223  * address(es). @hostname may be an ASCII-only or UTF-8 hostname, or
 224  * the textual form of an IP address (in which case this just becomes
 225  * a wrapper around g_inet_address_new_from_string()).
 226  *
 227  * On success, g_resolver_lookup_by_name() will return a #GList of
 228  * #GInetAddress, sorted in order of preference. (That is, you should
 229  * attempt to connect to the first address first, then the second if
 230  * the first fails, etc.)
 231  *
 232  * If the DNS resolution fails, @error (if non-%NULL) will be set to a
 233  * value from #GResolverError.
 234  *
 235  * If @cancellable is non-%NULL, it can be used to cancel the
 236  * operation, in which case @error (if non-%NULL) will be set to
 237  * %G_IO_ERROR_CANCELLED.
 238  *
 239  * If you are planning to connect to a socket on the resolved IP
 240  * address, it may be easier to create a #GNetworkAddress and use its
 241  * #GSocketConnectable interface.
 242  *
 243  * Return value: (element-type GInetAddress) (transfer full): a #GList
 244  * of #GInetAddress, or %NULL on error. You
 245  * must unref each of the addresses and free the list when you are
 246  * done with it. (You can use g_resolver_free_addresses() to do this.)
 247  *
 248  * Since: 2.22
 249  */
 250 GList *
 251 g_resolver_lookup_by_name (GResolver     *resolver,
 252                            const gchar   *hostname,
 253                            GCancellable  *cancellable,
 254                            GError       **error)
 255 {
 256   GInetAddress *addr;
 257   GList *addrs;
 258   gchar *ascii_hostname = NULL;
 259
 260   g_return_val_if_fail (G_IS_RESOLVER (resolver), NULL);
 261   g_return_val_if_fail (hostname != NULL, NULL);
 262
 263   /* Check if @hostname is just an IP address */
 264   addr = g_inet_address_new_from_string (hostname);
 265   if (addr)
 266     return g_list_append (NULL, addr);
 267
 268   if (g_hostname_is_non_ascii (hostname))
 269     hostname = ascii_hostname = g_hostname_to_ascii (hostname);
 270
 271   g_resolver_maybe_reload (resolver);
 272   addrs = G_RESOLVER_GET_CLASS (resolver)->
 273     lookup_by_name (resolver, hostname, cancellable, error);
 274
 275   g_free (ascii_hostname);
 276   return addrs;
 277 }
 278
 279 /**
 280  * g_resolver_lookup_by_name_async:
 281  * @resolver: a #GResolver
 282  * @hostname: the hostname to look up the address of
 283  * @cancellable: (allow-none): a #GCancellable, or %NULL
 284  * @callback: (scope async): callback to call after resolution completes
 285  * @user_data: (closure): data for @callback
 286  *
 287  * Begins asynchronously resolving @hostname to determine its
 288  * associated IP address(es), and eventually calls @callback, which
 289  * must call g_resolver_lookup_by_name_finish() to get the result.
 290  * See g_resolver_lookup_by_name() for more details.
 291  *
 292  * Since: 2.22
 293  */
 294 void
 295 g_resolver_lookup_by_name_async (GResolver           *resolver,
 296                                  const gchar         *hostname,
 297                                  GCancellable        *cancellable,
 298                                  GAsyncReadyCallback  callback,
 299                                  gpointer             user_data)
 300 {
 301   GInetAddress *addr;
 302   gchar *ascii_hostname = NULL;
 303
 304   g_return_if_fail (G_IS_RESOLVER (resolver));
 305   g_return_if_fail (hostname != NULL);
 306
 307   /* Check if @hostname is just an IP address */
 308   addr = g_inet_address_new_from_string (hostname);
 309   if (addr)
 310     {
 311       GSimpleAsyncResult *simple;
 312
 313       simple = g_simple_async_result_new (G_OBJECT (resolver),
 314                                           callback, user_data,
 315                                           g_resolver_lookup_by_name_async);
 316
 317       g_simple_async_result_set_op_res_gpointer (simple, addr, g_object_unref);
 318       g_simple_async_result_complete_in_idle (simple);
 319       g_object_unref (simple);
 320       return;
 321     }
 322
 323   if (g_hostname_is_non_ascii (hostname))
 324     hostname = ascii_hostname = g_hostname_to_ascii (hostname);
 325
 326   g_resolver_maybe_reload (resolver);
 327   G_RESOLVER_GET_CLASS (resolver)->
 328     lookup_by_name_async (resolver, hostname, cancellable, callback, user_data);
 329
 330   g_free (ascii_hostname);
 331 }
 332
 333 /**
 334  * g_resolver_lookup_by_name_finish:
 335  * @resolver: a #GResolver
 336  * @result: the result passed to your #GAsyncReadyCallback
 337  * @error: return location for a #GError, or %NULL
 338  *
 339  * Retrieves the result of a call to
 340  * g_resolver_lookup_by_name_async().
 341  *
 342  * If the DNS resolution failed, @error (if non-%NULL) will be set to
 343  * a value from #GResolverError. If the operation was cancelled,
 344  * @error will be set to %G_IO_ERROR_CANCELLED.
 345  *
 346  * Return value: (element-type GInetAddress) (transfer full): a #GList
 347  * of #GInetAddress, or %NULL on error. See g_resolver_lookup_by_name()
 348  * for more details.
 349  *
 350  * Since: 2.22
 351  */
 352 GList *
 353 g_resolver_lookup_by_name_finish (GResolver     *resolver,
 354                                   GAsyncResult  *result,
 355                                   GError       **error)
 356 {
 357   g_return_val_if_fail (G_IS_RESOLVER (resolver), NULL);
 358
 359   if (G_IS_SIMPLE_ASYNC_RESULT (result))
 360     {
 361       GSimpleAsyncResult *simple = G_SIMPLE_ASYNC_RESULT (result);
 362
 363       if (g_simple_async_result_propagate_error (simple, error))
 364         return NULL;
 365
 366       /* Handle the stringified-IP-addr case */
 367       if (g_simple_async_result_get_source_tag (simple) == g_resolver_lookup_by_name_async)
 368         {
 369           GInetAddress *addr;
 370
 371           addr = g_simple_async_result_get_op_res_gpointer (simple);
 372           return g_list_append (NULL, g_object_ref (addr));
 373         }
 374     }
 375
 376   return G_RESOLVER_GET_CLASS (resolver)->
 377     lookup_by_name_finish (resolver, result, error);
 378 }
 379
 380 /**
 381  * g_resolver_free_addresses: (skip)
 382  * @addresses: a #GList of #GInetAddress
 383  *
 384  * Frees @addresses (which should be the return value from
 385  * g_resolver_lookup_by_name() or g_resolver_lookup_by_name_finish()).
 386  * (This is a convenience method; you can also simply free the results
 387  * by hand.)
 388  *
 389  * Since: 2.22
 390  */
 391 void
 392 g_resolver_free_addresses (GList *addresses)
 393 {
 394   GList *a;
 395
 396   for (a = addresses; a; a = a->next)
 397     g_object_unref (a->data);
 398   g_list_free (addresses);
 399 }
 400
 401 /**
 402  * g_resolver_lookup_by_address:
 403  * @resolver: a #GResolver
 404  * @address: the address to reverse-resolve
 405  * @cancellable: (allow-none): a #GCancellable, or %NULL
 406  * @error: return location for a #GError, or %NULL
 407  *
 408  * Synchronously reverse-resolves @address to determine its
 409  * associated hostname.
 410  *
 411  * If the DNS resolution fails, @error (if non-%NULL) will be set to
 412  * a value from #GResolverError.
 413  *
 414  * If @cancellable is non-%NULL, it can be used to cancel the
 415  * operation, in which case @error (if non-%NULL) will be set to
 416  * %G_IO_ERROR_CANCELLED.
 417  *
 418  * Return value: a hostname (either ASCII-only, or in ASCII-encoded
 419  *     form), or %NULL on error.
 420  *
 421  * Since: 2.22
 422  */
 423 gchar *
 424 g_resolver_lookup_by_address (GResolver     *resolver,
 425                               GInetAddress  *address,
 426                               GCancellable  *cancellable,
 427                               GError       **error)
 428 {
 429   g_return_val_if_fail (G_IS_RESOLVER (resolver), NULL);
 430   g_return_val_if_fail (G_IS_INET_ADDRESS (address), NULL);
 431
 432   g_resolver_maybe_reload (resolver);
 433   return G_RESOLVER_GET_CLASS (resolver)->
 434     lookup_by_address (resolver, address, cancellable, error);
 435 }
 436
 437 /**
 438  * g_resolver_lookup_by_address_async:
 439  * @resolver: a #GResolver
 440  * @address: the address to reverse-resolve
 441  * @cancellable: (allow-none): a #GCancellable, or %NULL
 442  * @callback: (scope async): callback to call after resolution completes
 443  * @user_data: (closure): data for @callback
 444  *
 445  * Begins asynchronously reverse-resolving @address to determine its
 446  * associated hostname, and eventually calls @callback, which must
 447  * call g_resolver_lookup_by_address_finish() to get the final result.
 448  *
 449  * Since: 2.22
 450  */
 451 void
 452 g_resolver_lookup_by_address_async (GResolver           *resolver,
 453                                     GInetAddress        *address,
 454                                     GCancellable        *cancellable,
 455                                     GAsyncReadyCallback  callback,
 456                                     gpointer             user_data)
 457 {
 458   g_return_if_fail (G_IS_RESOLVER (resolver));
 459   g_return_if_fail (G_IS_INET_ADDRESS (address));
 460
 461   g_resolver_maybe_reload (resolver);
 462   G_RESOLVER_GET_CLASS (resolver)->
 463     lookup_by_address_async (resolver, address, cancellable, callback, user_data);
 464 }
 465
 466 /**
 467  * g_resolver_lookup_by_address_finish:
 468  * @resolver: a #GResolver
 469  * @result: the result passed to your #GAsyncReadyCallback
 470  * @error: return location for a #GError, or %NULL
 471  *
 472  * Retrieves the result of a previous call to
 473  * g_resolver_lookup_by_address_async().
 474  *
 475  * If the DNS resolution failed, @error (if non-%NULL) will be set to
 476  * a value from #GResolverError. If the operation was cancelled,
 477  * @error will be set to %G_IO_ERROR_CANCELLED.
 478  *
 479  * Return value: a hostname (either ASCII-only, or in ASCII-encoded
 480  * form), or %NULL on error.
 481  *
 482  * Since: 2.22
 483  */
 484 gchar *
 485 g_resolver_lookup_by_address_finish (GResolver     *resolver,
 486                                      GAsyncResult  *result,
 487                                      GError       **error)
 488 {
 489   g_return_val_if_fail (G_IS_RESOLVER (resolver), NULL);
 490
 491   if (G_IS_SIMPLE_ASYNC_RESULT (result))
 492     {
 493       GSimpleAsyncResult *simple = G_SIMPLE_ASYNC_RESULT (result);
 494
 495       if (g_simple_async_result_propagate_error (simple, error))
 496         return NULL;
 497     }
 498
 499   return G_RESOLVER_GET_CLASS (resolver)->
 500     lookup_by_address_finish (resolver, result, error);
 501 }
 502
 503 static gchar *
 504 g_resolver_get_service_rrname (const char *service,
 505                                const char *protocol,
 506                                const char *domain)
 507 {
 508   gchar *rrname, *ascii_domain = NULL;
 509
 510   if (g_hostname_is_non_ascii (domain))
 511     domain = ascii_domain = g_hostname_to_ascii (domain);
 512
 513   rrname = g_strdup_printf ("_%s._%s.%s", service, protocol, domain);
 514
 515   g_free (ascii_domain);
 516   return rrname;
 517 }
 518
 519 /**
 520  * g_resolver_lookup_service:
 521  * @resolver: a #GResolver
 522  * @service: the service type to look up (eg, "ldap")
 523  * @protocol: the networking protocol to use for @service (eg, "tcp")
 524  * @domain: the DNS domain to look up the service in
 525  * @cancellable: (allow-none): a #GCancellable, or %NULL
 526  * @error: return location for a #GError, or %NULL
 527  *
 528  * Synchronously performs a DNS SRV lookup for the given @service and
 529  * @protocol in the given @domain and returns an array of #GSrvTarget.
 530  * @domain may be an ASCII-only or UTF-8 hostname. Note also that the
 531  * @service and @protocol arguments <emphasis>do not</emphasis>
 532  * include the leading underscore that appears in the actual DNS
 533  * entry.
 534  *
 535  * On success, g_resolver_lookup_service() will return a #GList of
 536  * #GSrvTarget, sorted in order of preference. (That is, you should
 537  * attempt to connect to the first target first, then the second if
 538  * the first fails, etc.)
 539  *
 540  * If the DNS resolution fails, @error (if non-%NULL) will be set to
 541  * a value from #GResolverError.
 542  *
 543  * If @cancellable is non-%NULL, it can be used to cancel the
 544  * operation, in which case @error (if non-%NULL) will be set to
 545  * %G_IO_ERROR_CANCELLED.
 546  *
 547  * If you are planning to connect to the service, it is usually easier
 548  * to create a #GNetworkService and use its #GSocketConnectable
 549  * interface.
 550  *
 551  * Return value: (element-type GSrvTarget) (transfer full): a #GList of #GSrvTarget,
 552  * or %NULL on error. You must free each of the targets and the list when you are
 553  * done with it. (You can use g_resolver_free_targets() to do this.)
 554  *
 555  * Since: 2.22
 556  */
 557 GList *
 558 g_resolver_lookup_service (GResolver     *resolver,
 559                            const gchar   *service,
 560                            const gchar   *protocol,
 561                            const gchar   *domain,
 562                            GCancellable  *cancellable,
 563                            GError       **error)
 564 {
 565   GList *targets;
 566   gchar *rrname;
 567
 568   g_return_val_if_fail (G_IS_RESOLVER (resolver), NULL);
 569   g_return_val_if_fail (service != NULL, NULL);
 570   g_return_val_if_fail (protocol != NULL, NULL);
 571   g_return_val_if_fail (domain != NULL, NULL);
 572
 573   rrname = g_resolver_get_service_rrname (service, protocol, domain);
 574
 575   g_resolver_maybe_reload (resolver);
 576   targets = G_RESOLVER_GET_CLASS (resolver)->
 577     lookup_service (resolver, rrname, cancellable, error);
 578
 579   g_free (rrname);
 580   return targets;
 581 }
 582
 583 /**
 584  * g_resolver_lookup_service_async:
 585  * @resolver: a #GResolver
 586  * @service: the service type to look up (eg, "ldap")
 587  * @protocol: the networking protocol to use for @service (eg, "tcp")
 588  * @domain: the DNS domain to look up the service in
 589  * @cancellable: (allow-none): a #GCancellable, or %NULL
 590  * @callback: (scope async): callback to call after resolution completes
 591  * @user_data: (closure): data for @callback
 592  *
 593  * Begins asynchronously performing a DNS SRV lookup for the given
 594  * @service and @protocol in the given @domain, and eventually calls
 595  * @callback, which must call g_resolver_lookup_service_finish() to
 596  * get the final result. See g_resolver_lookup_service() for more
 597  * details.
 598  *
 599  * Since: 2.22
 600  */
 601 void
 602 g_resolver_lookup_service_async (GResolver           *resolver,
 603                                  const gchar         *service,
 604                                  const gchar         *protocol,
 605                                  const gchar         *domain,
 606                                  GCancellable        *cancellable,
 607                                  GAsyncReadyCallback  callback,
 608                                  gpointer             user_data)
 609 {
 610   gchar *rrname;
 611
 612   g_return_if_fail (G_IS_RESOLVER (resolver));
 613   g_return_if_fail (service != NULL);
 614   g_return_if_fail (protocol != NULL);
 615   g_return_if_fail (domain != NULL);
 616
 617   rrname = g_resolver_get_service_rrname (service, protocol, domain);
 618
 619   g_resolver_maybe_reload (resolver);
 620   G_RESOLVER_GET_CLASS (resolver)->
 621     lookup_service_async (resolver, rrname, cancellable, callback, user_data);
 622
 623   g_free (rrname);
 624 }
 625
 626 /**
 627  * g_resolver_lookup_service_finish:
 628  * @resolver: a #GResolver
 629  * @result: the result passed to your #GAsyncReadyCallback
 630  * @error: return location for a #GError, or %NULL
 631  *
 632  * Retrieves the result of a previous call to
 633  * g_resolver_lookup_service_async().
 634  *
 635  * If the DNS resolution failed, @error (if non-%NULL) will be set to
 636  * a value from #GResolverError. If the operation was cancelled,
 637  * @error will be set to %G_IO_ERROR_CANCELLED.
 638  *
 639  * Return value: (element-type GSrvTarget) (transfer full): a #GList of #GSrvTarget,
 640  * or %NULL on error. See g_resolver_lookup_service() for more details.
 641  *
 642  * Since: 2.22
 643  */
 644 GList *
 645 g_resolver_lookup_service_finish (GResolver     *resolver,
 646                                   GAsyncResult  *result,
 647                                   GError       **error)
 648 {
 649   g_return_val_if_fail (G_IS_RESOLVER (resolver), NULL);
 650
 651   if (G_IS_SIMPLE_ASYNC_RESULT (result))
 652     {
 653       GSimpleAsyncResult *simple = G_SIMPLE_ASYNC_RESULT (result);
 654
 655       if (g_simple_async_result_propagate_error (simple, error))
 656         return NULL;
 657     }
 658
 659   return G_RESOLVER_GET_CLASS (resolver)->
 660     lookup_service_finish (resolver, result, error);
 661 }
 662
 663 /**
 664  * g_resolver_free_targets: (skip)
 665  * @targets: a #GList of #GSrvTarget
 666  *
 667  * Frees @targets (which should be the return value from
 668  * g_resolver_lookup_service() or g_resolver_lookup_service_finish()).
 669  * (This is a convenience method; you can also simply free the
 670  * results by hand.)
 671  *
 672  * Since: 2.22
 673  */
 674 void
 675 g_resolver_free_targets (GList *targets)
 676 {
 677   GList *t;
 678
 679   for (t = targets; t; t = t->next)
 680     g_srv_target_free (t->data);
 681   g_list_free (targets);
 682 }
 683
 684 /**
 685  * g_resolver_error_quark:
 686  *
 687  * Gets the #GResolver Error Quark.
 688  *
 689  * Return value: a #GQuark.
 690  *
 691  * Since: 2.22
 692  */
 693 GQuark
 694 g_resolver_error_quark (void)
 695 {
 696   return g_quark_from_static_string ("g-resolver-error-quark");
 697 }
 698
 699
 700 static GResolverError
 701 g_resolver_error_from_addrinfo_error (gint err)
 702 {
 703   switch (err)
 704     {
 705     case EAI_FAIL:
 706 #if defined(EAI_NODATA) && (EAI_NODATA != EAI_NONAME)
 707     case EAI_NODATA:
 708 #endif
 709     case EAI_NONAME:
 710       return G_RESOLVER_ERROR_NOT_FOUND;
 711
 712     case EAI_AGAIN:
 713       return G_RESOLVER_ERROR_TEMPORARY_FAILURE;
 714
 715     default:
 716       return G_RESOLVER_ERROR_INTERNAL;
 717     }
 718 }
 719
 720 struct addrinfo _g_resolver_addrinfo_hints;
 721
 722 /* Private method to process a getaddrinfo() response. */
 723 GList *
 724 _g_resolver_addresses_from_addrinfo (const char       *hostname,
 725                                      struct addrinfo  *res,
 726                                      gint              gai_retval,
 727                                      GError          **error)
 728 {
 729   struct addrinfo *ai;
 730   GSocketAddress *sockaddr;
 731   GInetAddress *addr;
 732   GList *addrs;
 733
 734   if (gai_retval != 0)
 735     {
 736       g_set_error (error, G_RESOLVER_ERROR,
 737                    g_resolver_error_from_addrinfo_error (gai_retval),
 738                    _("Error resolving '%s': %s"),
 739                    hostname, gai_strerror (gai_retval));
 740       return NULL;
 741     }
 742
 743   g_return_val_if_fail (res != NULL, NULL);
 744
 745   addrs = NULL;
 746   for (ai = res; ai; ai = ai->ai_next)
 747     {
 748       sockaddr = g_socket_address_new_from_native (ai->ai_addr, ai->ai_addrlen);
 749       if (!sockaddr || !G_IS_INET_SOCKET_ADDRESS (sockaddr))
 750         continue;
 751
 752       addr = g_object_ref (g_inet_socket_address_get_address ((GInetSocketAddress *)sockaddr));
 753       addrs = g_list_prepend (addrs, addr);
 754       g_object_unref (sockaddr);
 755     }
 756
 757   return g_list_reverse (addrs);
 758 }
 759
 760 /* Private method to set up a getnameinfo() request */
 761 void
 762 _g_resolver_address_to_sockaddr (GInetAddress            *address,
 763                                  struct sockaddr_storage *sa,
 764                                  gsize                   *len)
 765 {
 766   GSocketAddress *sockaddr;
 767
 768   sockaddr = g_inet_socket_address_new (address, 0);
 769   g_socket_address_to_native (sockaddr, (struct sockaddr *)sa, sizeof (*sa), NULL);
 770   *len = g_socket_address_get_native_size (sockaddr);
 771   g_object_unref (sockaddr);
 772 }
 773
 774 /* Private method to process a getnameinfo() response. */
 775 char *
 776 _g_resolver_name_from_nameinfo (GInetAddress  *address,
 777                                 const gchar   *name,
 778                                 gint           gni_retval,
 779                                 GError       **error)
 780 {
 781   if (gni_retval != 0)
 782     {
 783       gchar *phys;
 784
 785       phys = g_inet_address_to_string (address);
 786       g_set_error (error, G_RESOLVER_ERROR,
 787                    g_resolver_error_from_addrinfo_error (gni_retval),
 788                    _("Error reverse-resolving '%s': %s"),
 789                    phys ? phys : "(unknown)", gai_strerror (gni_retval));
 790       g_free (phys);
 791       return NULL;
 792     }
 793
 794   return g_strdup (name);
 795 }
 796
 797 #if defined(G_OS_UNIX)
 798 /* Private method to process a res_query response into GSrvTargets */
 799 GList *
 800 _g_resolver_targets_from_res_query (const gchar      *rrname,
 801                                     guchar           *answer,
 802                                     gint              len,
 803                                     gint              herr,
 804                                     GError          **error)
 805 {
 806   gint count;
 807   gchar namebuf[1024];
 808   guchar *end, *p;
 809   guint16 type, qclass, rdlength, priority, weight, port;
 810   guint32 ttl;
 811   HEADER *header;
 812   GSrvTarget *target;
 813   GList *targets;
 814
 815   if (len <= 0)
 816     {
 817       GResolverError errnum;
 818       const gchar *format;
 819
 820       if (len == 0 || herr == HOST_NOT_FOUND || herr == NO_DATA)
 821         {
 822           errnum = G_RESOLVER_ERROR_NOT_FOUND;
 823           format = _("No service record for '%s'");
 824         }
 825       else if (herr == TRY_AGAIN)
 826         {
 827           errnum = G_RESOLVER_ERROR_TEMPORARY_FAILURE;
 828           format = _("Temporarily unable to resolve '%s'");
 829         }
 830       else
 831         {
 832           errnum = G_RESOLVER_ERROR_INTERNAL;
 833           format = _("Error resolving '%s'");
 834         }
 835
 836       g_set_error (error, G_RESOLVER_ERROR, errnum, format, rrname);
 837       return NULL;
 838     }
 839
 840   targets = NULL;
 841
 842   header = (HEADER *)answer;
 843   p = answer + sizeof (HEADER);
 844   end = answer + len;
 845
 846   /* Skip query */
 847   count = ntohs (header->qdcount);
 848   while (count-- && p < end)
 849     {
 850       p += dn_expand (answer, end, p, namebuf, sizeof (namebuf));
 851       p += 4;
 852     }
 853
 854   /* Read answers */
 855   count = ntohs (header->ancount);
 856   while (count-- && p < end)
 857     {
 858       p += dn_expand (answer, end, p, namebuf, sizeof (namebuf));
 859       GETSHORT (type, p);
 860       GETSHORT (qclass, p);
 861       GETLONG  (ttl, p);
 862       ttl = ttl; /* To avoid -Wunused-but-set-variable */
 863       GETSHORT (rdlength, p);
 864
 865       if (type != T_SRV || qclass != C_IN)
 866         {
 867           p += rdlength;
 868           continue;
 869         }
 870
 871       GETSHORT (priority, p);
 872       GETSHORT (weight, p);
 873       GETSHORT (port, p);
 874       p += dn_expand (answer, end, p, namebuf, sizeof (namebuf));
 875
 876       target = g_srv_target_new (namebuf, port, priority, weight);
 877       targets = g_list_prepend (targets, target);
 878     }
 879
 880   return g_srv_target_list_sort (targets);
 881 }
 882 #elif defined(G_OS_WIN32)
 883 /* Private method to process a DnsQuery response into GSrvTargets */
 884 GList *
 885 _g_resolver_targets_from_DnsQuery (const gchar  *rrname,
 886                                    DNS_STATUS    status,
 887                                    DNS_RECORD   *results,
 888                                    GError      **error)
 889 {
 890   DNS_RECORD *rec;
 891   GSrvTarget *target;
 892   GList *targets;
 893
 894   if (status != ERROR_SUCCESS)
 895     {
 896       GResolverError errnum;
 897       const gchar *format;
 898
 899       if (status == DNS_ERROR_RCODE_NAME_ERROR)
 900         {
 901           errnum = G_RESOLVER_ERROR_NOT_FOUND;
 902           format = _("No service record for '%s'");
 903         }
 904       else if (status == DNS_ERROR_RCODE_SERVER_FAILURE)
 905         {
 906           errnum = G_RESOLVER_ERROR_TEMPORARY_FAILURE;
 907           format = _("Temporarily unable to resolve '%s'");
 908         }
 909       else
 910         {
 911           errnum = G_RESOLVER_ERROR_INTERNAL;
 912           format = _("Error resolving '%s'");
 913         }
 914
 915       g_set_error (error, G_RESOLVER_ERROR, errnum, format, rrname);
 916       return NULL;
 917     }
 918
 919   targets = NULL;
 920   for (rec = results; rec; rec = rec->pNext)
 921     {
 922       if (rec->wType != DNS_TYPE_SRV)
 923         continue;
 924
 925       target = g_srv_target_new (rec->Data.SRV.pNameTarget,
 926                                  rec->Data.SRV.wPort,
 927                                  rec->Data.SRV.wPriority,
 928                                  rec->Data.SRV.wWeight);
 929       targets = g_list_prepend (targets, target);
 930     }
 931
 932   return g_srv_target_list_sort (targets);
 933 }
 934
 935 #endif