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