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1 office 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, see <http://www.gnu.org/licenses/>.
19 */
20  
21 #include "config.h"
22 #include <glib.h>
23 #include "glibintl.h"
24  
25 #include "gresolver.h"
26 #include "gnetworkingprivate.h"
27 #include "gasyncresult.h"
28 #include "ginetaddress.h"
29 #include "gtask.h"
30 #include "gsrvtarget.h"
31 #include "gthreadedresolver.h"
32  
33 #ifdef G_OS_UNIX
34 #include <sys/stat.h>
35 #endif
36  
37 #include <stdlib.h>
38  
39  
40 /**
41 * SECTION:gresolver
42 * @short_description: Asynchronous and cancellable DNS resolver
43 * @include: gio/gio.h
44 *
45 * #GResolver provides cancellable synchronous and asynchronous DNS
46 * resolution, for hostnames (g_resolver_lookup_by_address(),
47 * g_resolver_lookup_by_name() and their async variants) and SRV
48 * (service) records (g_resolver_lookup_service()).
49 *
50 * #GNetworkAddress and #GNetworkService provide wrappers around
51 * #GResolver functionality that also implement #GSocketConnectable,
52 * making it easy to connect to a remote host/service.
53 */
54  
55 enum {
56 RELOAD,
57 LAST_SIGNAL
58 };
59  
60 static guint signals[LAST_SIGNAL] = { 0 };
61  
62 struct _GResolverPrivate {
63 #ifdef G_OS_UNIX
64 time_t resolv_conf_timestamp;
65 #else
66 int dummy;
67 #endif
68 };
69  
70 /**
71 * GResolver:
72 *
73 * The object that handles DNS resolution. Use g_resolver_get_default()
74 * to get the default resolver.
75 */
76 G_DEFINE_TYPE_WITH_CODE (GResolver, g_resolver, G_TYPE_OBJECT,
77 G_ADD_PRIVATE (GResolver)
78 g_networking_init ();)
79  
80 static GList *
81 srv_records_to_targets (GList *records)
82 {
83 const gchar *hostname;
84 guint16 port, priority, weight;
85 GSrvTarget *target;
86 GList *l;
87  
88 for (l = records; l != NULL; l = g_list_next (l))
89 {
90 g_variant_get (l->data, "(qqq&s)", &priority, &weight, &port, &hostname);
91 target = g_srv_target_new (hostname, port, priority, weight);
92 g_variant_unref (l->data);
93 l->data = target;
94 }
95  
96 return g_srv_target_list_sort (records);
97 }
98  
99 static GList *
100 g_resolver_real_lookup_service (GResolver *resolver,
101 const gchar *rrname,
102 GCancellable *cancellable,
103 GError **error)
104 {
105 GList *records;
106  
107 records = G_RESOLVER_GET_CLASS (resolver)->lookup_records (resolver,
108 rrname,
109 G_RESOLVER_RECORD_SRV,
110 cancellable,
111 error);
112  
113 return srv_records_to_targets (records);
114 }
115  
116 static void
117 g_resolver_real_lookup_service_async (GResolver *resolver,
118 const gchar *rrname,
119 GCancellable *cancellable,
120 GAsyncReadyCallback callback,
121 gpointer user_data)
122 {
123 G_RESOLVER_GET_CLASS (resolver)->lookup_records_async (resolver,
124 rrname,
125 G_RESOLVER_RECORD_SRV,
126 cancellable,
127 callback,
128 user_data);
129 }
130  
131 static GList *
132 g_resolver_real_lookup_service_finish (GResolver *resolver,
133 GAsyncResult *result,
134 GError **error)
135 {
136 GList *records;
137  
138 records = G_RESOLVER_GET_CLASS (resolver)->lookup_records_finish (resolver,
139 result,
140 error);
141  
142 return srv_records_to_targets (records);
143 }
144  
145 static void
146 g_resolver_class_init (GResolverClass *resolver_class)
147 {
148 /* Automatically pass these over to the lookup_records methods */
149 resolver_class->lookup_service = g_resolver_real_lookup_service;
150 resolver_class->lookup_service_async = g_resolver_real_lookup_service_async;
151 resolver_class->lookup_service_finish = g_resolver_real_lookup_service_finish;
152  
153 /**
154 * GResolver::reload:
155 * @resolver: a #GResolver
156 *
157 * Emitted when the resolver notices that the system resolver
158 * configuration has changed.
159 **/
160 signals[RELOAD] =
161 g_signal_new (I_("reload"),
162 G_TYPE_RESOLVER,
163 G_SIGNAL_RUN_LAST,
164 G_STRUCT_OFFSET (GResolverClass, reload),
165 NULL, NULL,
166 g_cclosure_marshal_VOID__VOID,
167 G_TYPE_NONE, 0);
168 }
169  
170 static void
171 g_resolver_init (GResolver *resolver)
172 {
173 #ifdef G_OS_UNIX
174 struct stat st;
175 #endif
176  
177 resolver->priv = g_resolver_get_instance_private (resolver);
178  
179 #ifdef G_OS_UNIX
180 if (stat (_PATH_RESCONF, &st) == 0)
181 resolver->priv->resolv_conf_timestamp = st.st_mtime;
182 #endif
183 }
184  
185 static GResolver *default_resolver;
186  
187 /**
188 * g_resolver_get_default:
189 *
190 * Gets the default #GResolver. You should unref it when you are done
191 * with it. #GResolver may use its reference count as a hint about how
192 * many threads it should allocate for concurrent DNS resolutions.
193 *
194 * Returns: (transfer full): the default #GResolver.
195 *
196 * Since: 2.22
197 */
198 GResolver *
199 g_resolver_get_default (void)
200 {
201 if (!default_resolver)
202 default_resolver = g_object_new (G_TYPE_THREADED_RESOLVER, NULL);
203  
204 return g_object_ref (default_resolver);
205 }
206  
207 /**
208 * g_resolver_set_default:
209 * @resolver: the new default #GResolver
210 *
211 * Sets @resolver to be the application's default resolver (reffing
212 * @resolver, and unreffing the previous default resolver, if any).
213 * Future calls to g_resolver_get_default() will return this resolver.
214 *
215 * This can be used if an application wants to perform any sort of DNS
216 * caching or "pinning"; it can implement its own #GResolver that
217 * calls the original default resolver for DNS operations, and
218 * implements its own cache policies on top of that, and then set
219 * itself as the default resolver for all later code to use.
220 *
221 * Since: 2.22
222 */
223 void
224 g_resolver_set_default (GResolver *resolver)
225 {
226 if (default_resolver)
227 g_object_unref (default_resolver);
228 default_resolver = g_object_ref (resolver);
229 }
230  
231 /* Bionic has res_init() but it's not in any header */
232 #ifdef __BIONIC__
233 int res_init (void);
234 #endif
235  
236 static void
237 g_resolver_maybe_reload (GResolver *resolver)
238 {
239 #ifdef G_OS_UNIX
240 struct stat st;
241  
242 if (stat (_PATH_RESCONF, &st) == 0)
243 {
244 if (st.st_mtime != resolver->priv->resolv_conf_timestamp)
245 {
246 resolver->priv->resolv_conf_timestamp = st.st_mtime;
247 #ifdef HAVE_RES_INIT
248 res_init ();
249 #endif
250 g_signal_emit (resolver, signals[RELOAD], 0);
251 }
252 }
253 #endif
254 }
255  
256 /* filter out duplicates, cf. https://bugzilla.gnome.org/show_bug.cgi?id=631379 */
257 static void
258 remove_duplicates (GList *addrs)
259 {
260 GList *l;
261 GList *ll;
262 GList *lll;
263  
264 /* TODO: if this is too slow (it's O(n^2) but n is typically really
265 * small), we can do something more clever but note that we must not
266 * change the order of elements...
267 */
268 for (l = addrs; l != NULL; l = l->next)
269 {
270 GInetAddress *address = G_INET_ADDRESS (l->data);
271 for (ll = l->next; ll != NULL; ll = lll)
272 {
273 GInetAddress *other_address = G_INET_ADDRESS (ll->data);
274 lll = ll->next;
275 if (g_inet_address_equal (address, other_address))
276 {
277 g_object_unref (other_address);
278 /* we never return the first element */
279 g_warn_if_fail (g_list_delete_link (addrs, ll) == addrs);
280 }
281 }
282 }
283 }
284  
285 /* Note that this does not follow the "FALSE means @error is set"
286 * convention. The return value tells the caller whether it should
287 * return @addrs and @error to the caller right away, or if it should
288 * continue and trying to resolve the name as a hostname.
289 */
290 static gboolean
291 handle_ip_address (const char *hostname,
292 GList **addrs,
293 GError **error)
294 {
295 GInetAddress *addr;
296  
297 #ifndef G_OS_WIN32
298 struct in_addr ip4addr;
299 #endif
300  
301 addr = g_inet_address_new_from_string (hostname);
302 if (addr)
303 {
304 *addrs = g_list_append (NULL, addr);
305 return TRUE;
306 }
307  
308 *addrs = NULL;
309  
310 #ifdef G_OS_WIN32
311  
312 /* Reject IPv6 addresses that have brackets ('[' or ']') and/or port numbers,
313 * as no valid addresses should contain these at this point.
314 * Non-standard IPv4 addresses would be rejected during the call to
315 * getaddrinfo() later.
316 */
317 if (strrchr (hostname, '[') != NULL ||
318 strrchr (hostname, ']') != NULL)
319 #else
320  
321 /* Reject non-standard IPv4 numbers-and-dots addresses.
322 * g_inet_address_new_from_string() will have accepted any "real" IP
323 * address, so if inet_aton() succeeds, then it's an address we want
324 * to reject.
325 */
326 if (inet_aton (hostname, &ip4addr))
327 #endif
328 {
329 g_set_error (error, G_RESOLVER_ERROR, G_RESOLVER_ERROR_NOT_FOUND,
330 _("Error resolving '%s': %s"),
331 hostname, gai_strerror (EAI_NONAME));
332 return TRUE;
333 }
334  
335 return FALSE;
336 }
337  
338 /**
339 * g_resolver_lookup_by_name:
340 * @resolver: a #GResolver
341 * @hostname: the hostname to look up
342 * @cancellable: (allow-none): a #GCancellable, or %NULL
343 * @error: return location for a #GError, or %NULL
344 *
345 * Synchronously resolves @hostname to determine its associated IP
346 * address(es). @hostname may be an ASCII-only or UTF-8 hostname, or
347 * the textual form of an IP address (in which case this just becomes
348 * a wrapper around g_inet_address_new_from_string()).
349 *
350 * On success, g_resolver_lookup_by_name() will return a non-empty #GList of
351 * #GInetAddress, sorted in order of preference and guaranteed to not
352 * contain duplicates. That is, if using the result to connect to
353 * @hostname, you should attempt to connect to the first address
354 * first, then the second if the first fails, etc. If you are using
355 * the result to listen on a socket, it is appropriate to add each
356 * result using e.g. g_socket_listener_add_address().
357 *
358 * If the DNS resolution fails, @error (if non-%NULL) will be set to a
359 * value from #GResolverError and %NULL will be returned.
360 *
361 * If @cancellable is non-%NULL, it can be used to cancel the
362 * operation, in which case @error (if non-%NULL) will be set to
363 * %G_IO_ERROR_CANCELLED.
364 *
365 * If you are planning to connect to a socket on the resolved IP
366 * address, it may be easier to create a #GNetworkAddress and use its
367 * #GSocketConnectable interface.
368 *
369 * Returns: (element-type GInetAddress) (transfer full): a non-empty #GList
370 * of #GInetAddress, or %NULL on error. You
371 * must unref each of the addresses and free the list when you are
372 * done with it. (You can use g_resolver_free_addresses() to do this.)
373 *
374 * Since: 2.22
375 */
376 GList *
377 g_resolver_lookup_by_name (GResolver *resolver,
378 const gchar *hostname,
379 GCancellable *cancellable,
380 GError **error)
381 {
382 GList *addrs;
383 gchar *ascii_hostname = NULL;
384  
385 g_return_val_if_fail (G_IS_RESOLVER (resolver), NULL);
386 g_return_val_if_fail (hostname != NULL, NULL);
387  
388 /* Check if @hostname is just an IP address */
389 if (handle_ip_address (hostname, &addrs, error))
390 return addrs;
391  
392 if (g_hostname_is_non_ascii (hostname))
393 hostname = ascii_hostname = g_hostname_to_ascii (hostname);
394  
395 g_resolver_maybe_reload (resolver);
396 addrs = G_RESOLVER_GET_CLASS (resolver)->
397 lookup_by_name (resolver, hostname, cancellable, error);
398  
399 remove_duplicates (addrs);
400  
401 g_free (ascii_hostname);
402 return addrs;
403 }
404  
405 /**
406 * g_resolver_lookup_by_name_async:
407 * @resolver: a #GResolver
408 * @hostname: the hostname to look up the address of
409 * @cancellable: (allow-none): a #GCancellable, or %NULL
410 * @callback: (scope async): callback to call after resolution completes
411 * @user_data: (closure): data for @callback
412 *
413 * Begins asynchronously resolving @hostname to determine its
414 * associated IP address(es), and eventually calls @callback, which
415 * must call g_resolver_lookup_by_name_finish() to get the result.
416 * See g_resolver_lookup_by_name() for more details.
417 *
418 * Since: 2.22
419 */
420 void
421 g_resolver_lookup_by_name_async (GResolver *resolver,
422 const gchar *hostname,
423 GCancellable *cancellable,
424 GAsyncReadyCallback callback,
425 gpointer user_data)
426 {
427 gchar *ascii_hostname = NULL;
428 GList *addrs;
429 GError *error = NULL;
430  
431 g_return_if_fail (G_IS_RESOLVER (resolver));
432 g_return_if_fail (hostname != NULL);
433  
434 /* Check if @hostname is just an IP address */
435 if (handle_ip_address (hostname, &addrs, &error))
436 {
437 GTask *task;
438  
439 task = g_task_new (resolver, cancellable, callback, user_data);
440 g_task_set_source_tag (task, g_resolver_lookup_by_name_async);
441 if (addrs)
442 g_task_return_pointer (task, addrs, (GDestroyNotify) g_resolver_free_addresses);
443 else
444 g_task_return_error (task, error);
445 g_object_unref (task);
446 return;
447 }
448  
449 if (g_hostname_is_non_ascii (hostname))
450 hostname = ascii_hostname = g_hostname_to_ascii (hostname);
451  
452 g_resolver_maybe_reload (resolver);
453 G_RESOLVER_GET_CLASS (resolver)->
454 lookup_by_name_async (resolver, hostname, cancellable, callback, user_data);
455  
456 g_free (ascii_hostname);
457 }
458  
459 /**
460 * g_resolver_lookup_by_name_finish:
461 * @resolver: a #GResolver
462 * @result: the result passed to your #GAsyncReadyCallback
463 * @error: return location for a #GError, or %NULL
464 *
465 * Retrieves the result of a call to
466 * g_resolver_lookup_by_name_async().
467 *
468 * If the DNS resolution failed, @error (if non-%NULL) will be set to
469 * a value from #GResolverError. If the operation was cancelled,
470 * @error will be set to %G_IO_ERROR_CANCELLED.
471 *
472 * Returns: (element-type GInetAddress) (transfer full): a #GList
473 * of #GInetAddress, or %NULL on error. See g_resolver_lookup_by_name()
474 * for more details.
475 *
476 * Since: 2.22
477 */
478 GList *
479 g_resolver_lookup_by_name_finish (GResolver *resolver,
480 GAsyncResult *result,
481 GError **error)
482 {
483 GList *addrs;
484  
485 g_return_val_if_fail (G_IS_RESOLVER (resolver), NULL);
486  
487 if (g_async_result_legacy_propagate_error (result, error))
488 return NULL;
489 else if (g_async_result_is_tagged (result, g_resolver_lookup_by_name_async))
490 {
491 /* Handle the stringified-IP-addr case */
492 return g_task_propagate_pointer (G_TASK (result), error);
493 }
494  
495 addrs = G_RESOLVER_GET_CLASS (resolver)->
496 lookup_by_name_finish (resolver, result, error);
497  
498 remove_duplicates (addrs);
499  
500 return addrs;
501 }
502  
503 /**
504 * g_resolver_free_addresses: (skip)
505 * @addresses: a #GList of #GInetAddress
506 *
507 * Frees @addresses (which should be the return value from
508 * g_resolver_lookup_by_name() or g_resolver_lookup_by_name_finish()).
509 * (This is a convenience method; you can also simply free the results
510 * by hand.)
511 *
512 * Since: 2.22
513 */
514 void
515 g_resolver_free_addresses (GList *addresses)
516 {
517 GList *a;
518  
519 for (a = addresses; a; a = a->next)
520 g_object_unref (a->data);
521 g_list_free (addresses);
522 }
523  
524 /**
525 * g_resolver_lookup_by_address:
526 * @resolver: a #GResolver
527 * @address: the address to reverse-resolve
528 * @cancellable: (allow-none): a #GCancellable, or %NULL
529 * @error: return location for a #GError, or %NULL
530 *
531 * Synchronously reverse-resolves @address to determine its
532 * associated hostname.
533 *
534 * If the DNS resolution fails, @error (if non-%NULL) will be set to
535 * a value from #GResolverError.
536 *
537 * If @cancellable is non-%NULL, it can be used to cancel the
538 * operation, in which case @error (if non-%NULL) will be set to
539 * %G_IO_ERROR_CANCELLED.
540 *
541 * Returns: a hostname (either ASCII-only, or in ASCII-encoded
542 * form), or %NULL on error.
543 *
544 * Since: 2.22
545 */
546 gchar *
547 g_resolver_lookup_by_address (GResolver *resolver,
548 GInetAddress *address,
549 GCancellable *cancellable,
550 GError **error)
551 {
552 g_return_val_if_fail (G_IS_RESOLVER (resolver), NULL);
553 g_return_val_if_fail (G_IS_INET_ADDRESS (address), NULL);
554  
555 g_resolver_maybe_reload (resolver);
556 return G_RESOLVER_GET_CLASS (resolver)->
557 lookup_by_address (resolver, address, cancellable, error);
558 }
559  
560 /**
561 * g_resolver_lookup_by_address_async:
562 * @resolver: a #GResolver
563 * @address: the address to reverse-resolve
564 * @cancellable: (allow-none): a #GCancellable, or %NULL
565 * @callback: (scope async): callback to call after resolution completes
566 * @user_data: (closure): data for @callback
567 *
568 * Begins asynchronously reverse-resolving @address to determine its
569 * associated hostname, and eventually calls @callback, which must
570 * call g_resolver_lookup_by_address_finish() to get the final result.
571 *
572 * Since: 2.22
573 */
574 void
575 g_resolver_lookup_by_address_async (GResolver *resolver,
576 GInetAddress *address,
577 GCancellable *cancellable,
578 GAsyncReadyCallback callback,
579 gpointer user_data)
580 {
581 g_return_if_fail (G_IS_RESOLVER (resolver));
582 g_return_if_fail (G_IS_INET_ADDRESS (address));
583  
584 g_resolver_maybe_reload (resolver);
585 G_RESOLVER_GET_CLASS (resolver)->
586 lookup_by_address_async (resolver, address, cancellable, callback, user_data);
587 }
588  
589 /**
590 * g_resolver_lookup_by_address_finish:
591 * @resolver: a #GResolver
592 * @result: the result passed to your #GAsyncReadyCallback
593 * @error: return location for a #GError, or %NULL
594 *
595 * Retrieves the result of a previous call to
596 * g_resolver_lookup_by_address_async().
597 *
598 * If the DNS resolution failed, @error (if non-%NULL) will be set to
599 * a value from #GResolverError. If the operation was cancelled,
600 * @error will be set to %G_IO_ERROR_CANCELLED.
601 *
602 * Returns: a hostname (either ASCII-only, or in ASCII-encoded
603 * form), or %NULL on error.
604 *
605 * Since: 2.22
606 */
607 gchar *
608 g_resolver_lookup_by_address_finish (GResolver *resolver,
609 GAsyncResult *result,
610 GError **error)
611 {
612 g_return_val_if_fail (G_IS_RESOLVER (resolver), NULL);
613  
614 if (g_async_result_legacy_propagate_error (result, error))
615 return NULL;
616  
617 return G_RESOLVER_GET_CLASS (resolver)->
618 lookup_by_address_finish (resolver, result, error);
619 }
620  
621 static gchar *
622 g_resolver_get_service_rrname (const char *service,
623 const char *protocol,
624 const char *domain)
625 {
626 gchar *rrname, *ascii_domain = NULL;
627  
628 if (g_hostname_is_non_ascii (domain))
629 domain = ascii_domain = g_hostname_to_ascii (domain);
630  
631 rrname = g_strdup_printf ("_%s._%s.%s", service, protocol, domain);
632  
633 g_free (ascii_domain);
634 return rrname;
635 }
636  
637 /**
638 * g_resolver_lookup_service:
639 * @resolver: a #GResolver
640 * @service: the service type to look up (eg, "ldap")
641 * @protocol: the networking protocol to use for @service (eg, "tcp")
642 * @domain: the DNS domain to look up the service in
643 * @cancellable: (allow-none): a #GCancellable, or %NULL
644 * @error: return location for a #GError, or %NULL
645 *
646 * Synchronously performs a DNS SRV lookup for the given @service and
647 * @protocol in the given @domain and returns an array of #GSrvTarget.
648 * @domain may be an ASCII-only or UTF-8 hostname. Note also that the
649 * @service and @protocol arguments do not include the leading underscore
650 * that appears in the actual DNS entry.
651 *
652 * On success, g_resolver_lookup_service() will return a non-empty #GList of
653 * #GSrvTarget, sorted in order of preference. (That is, you should
654 * attempt to connect to the first target first, then the second if
655 * the first fails, etc.)
656 *
657 * If the DNS resolution fails, @error (if non-%NULL) will be set to
658 * a value from #GResolverError and %NULL will be returned.
659 *
660 * If @cancellable is non-%NULL, it can be used to cancel the
661 * operation, in which case @error (if non-%NULL) will be set to
662 * %G_IO_ERROR_CANCELLED.
663 *
664 * If you are planning to connect to the service, it is usually easier
665 * to create a #GNetworkService and use its #GSocketConnectable
666 * interface.
667 *
668 * Returns: (element-type GSrvTarget) (transfer full): a non-empty #GList of
669 * #GSrvTarget, or %NULL on error. You must free each of the targets and the
670 * list when you are done with it. (You can use g_resolver_free_targets() to do
671 * this.)
672 *
673 * Since: 2.22
674 */
675 GList *
676 g_resolver_lookup_service (GResolver *resolver,
677 const gchar *service,
678 const gchar *protocol,
679 const gchar *domain,
680 GCancellable *cancellable,
681 GError **error)
682 {
683 GList *targets;
684 gchar *rrname;
685  
686 g_return_val_if_fail (G_IS_RESOLVER (resolver), NULL);
687 g_return_val_if_fail (service != NULL, NULL);
688 g_return_val_if_fail (protocol != NULL, NULL);
689 g_return_val_if_fail (domain != NULL, NULL);
690  
691 rrname = g_resolver_get_service_rrname (service, protocol, domain);
692  
693 g_resolver_maybe_reload (resolver);
694 targets = G_RESOLVER_GET_CLASS (resolver)->
695 lookup_service (resolver, rrname, cancellable, error);
696  
697 g_free (rrname);
698 return targets;
699 }
700  
701 /**
702 * g_resolver_lookup_service_async:
703 * @resolver: a #GResolver
704 * @service: the service type to look up (eg, "ldap")
705 * @protocol: the networking protocol to use for @service (eg, "tcp")
706 * @domain: the DNS domain to look up the service in
707 * @cancellable: (allow-none): a #GCancellable, or %NULL
708 * @callback: (scope async): callback to call after resolution completes
709 * @user_data: (closure): data for @callback
710 *
711 * Begins asynchronously performing a DNS SRV lookup for the given
712 * @service and @protocol in the given @domain, and eventually calls
713 * @callback, which must call g_resolver_lookup_service_finish() to
714 * get the final result. See g_resolver_lookup_service() for more
715 * details.
716 *
717 * Since: 2.22
718 */
719 void
720 g_resolver_lookup_service_async (GResolver *resolver,
721 const gchar *service,
722 const gchar *protocol,
723 const gchar *domain,
724 GCancellable *cancellable,
725 GAsyncReadyCallback callback,
726 gpointer user_data)
727 {
728 gchar *rrname;
729  
730 g_return_if_fail (G_IS_RESOLVER (resolver));
731 g_return_if_fail (service != NULL);
732 g_return_if_fail (protocol != NULL);
733 g_return_if_fail (domain != NULL);
734  
735 rrname = g_resolver_get_service_rrname (service, protocol, domain);
736  
737 g_resolver_maybe_reload (resolver);
738 G_RESOLVER_GET_CLASS (resolver)->
739 lookup_service_async (resolver, rrname, cancellable, callback, user_data);
740  
741 g_free (rrname);
742 }
743  
744 /**
745 * g_resolver_lookup_service_finish:
746 * @resolver: a #GResolver
747 * @result: the result passed to your #GAsyncReadyCallback
748 * @error: return location for a #GError, or %NULL
749 *
750 * Retrieves the result of a previous call to
751 * g_resolver_lookup_service_async().
752 *
753 * If the DNS resolution failed, @error (if non-%NULL) will be set to
754 * a value from #GResolverError. If the operation was cancelled,
755 * @error will be set to %G_IO_ERROR_CANCELLED.
756 *
757 * Returns: (element-type GSrvTarget) (transfer full): a non-empty #GList of
758 * #GSrvTarget, or %NULL on error. See g_resolver_lookup_service() for more
759 * details.
760 *
761 * Since: 2.22
762 */
763 GList *
764 g_resolver_lookup_service_finish (GResolver *resolver,
765 GAsyncResult *result,
766 GError **error)
767 {
768 g_return_val_if_fail (G_IS_RESOLVER (resolver), NULL);
769  
770 if (g_async_result_legacy_propagate_error (result, error))
771 return NULL;
772  
773 return G_RESOLVER_GET_CLASS (resolver)->
774 lookup_service_finish (resolver, result, error);
775 }
776  
777 /**
778 * g_resolver_free_targets: (skip)
779 * @targets: a #GList of #GSrvTarget
780 *
781 * Frees @targets (which should be the return value from
782 * g_resolver_lookup_service() or g_resolver_lookup_service_finish()).
783 * (This is a convenience method; you can also simply free the
784 * results by hand.)
785 *
786 * Since: 2.22
787 */
788 void
789 g_resolver_free_targets (GList *targets)
790 {
791 GList *t;
792  
793 for (t = targets; t; t = t->next)
794 g_srv_target_free (t->data);
795 g_list_free (targets);
796 }
797  
798 /**
799 * g_resolver_lookup_records:
800 * @resolver: a #GResolver
801 * @rrname: the DNS name to lookup the record for
802 * @record_type: the type of DNS record to lookup
803 * @cancellable: (allow-none): a #GCancellable, or %NULL
804 * @error: return location for a #GError, or %NULL
805 *
806 * Synchronously performs a DNS record lookup for the given @rrname and returns
807 * a list of records as #GVariant tuples. See #GResolverRecordType for
808 * information on what the records contain for each @record_type.
809 *
810 * If the DNS resolution fails, @error (if non-%NULL) will be set to
811 * a value from #GResolverError and %NULL will be returned.
812 *
813 * If @cancellable is non-%NULL, it can be used to cancel the
814 * operation, in which case @error (if non-%NULL) will be set to
815 * %G_IO_ERROR_CANCELLED.
816 *
817 * Returns: (element-type GVariant) (transfer full): a non-empty #GList of
818 * #GVariant, or %NULL on error. You must free each of the records and the list
819 * when you are done with it. (You can use g_list_free_full() with
820 * g_variant_unref() to do this.)
821 *
822 * Since: 2.34
823 */
824 GList *
825 g_resolver_lookup_records (GResolver *resolver,
826 const gchar *rrname,
827 GResolverRecordType record_type,
828 GCancellable *cancellable,
829 GError **error)
830 {
831 GList *records;
832  
833 g_return_val_if_fail (G_IS_RESOLVER (resolver), NULL);
834 g_return_val_if_fail (rrname != NULL, NULL);
835  
836 g_resolver_maybe_reload (resolver);
837 records = G_RESOLVER_GET_CLASS (resolver)->
838 lookup_records (resolver, rrname, record_type, cancellable, error);
839  
840 return records;
841 }
842  
843 /**
844 * g_resolver_lookup_records_async:
845 * @resolver: a #GResolver
846 * @rrname: the DNS name to lookup the record for
847 * @record_type: the type of DNS record to lookup
848 * @cancellable: (allow-none): a #GCancellable, or %NULL
849 * @callback: (scope async): callback to call after resolution completes
850 * @user_data: (closure): data for @callback
851 *
852 * Begins asynchronously performing a DNS lookup for the given
853 * @rrname, and eventually calls @callback, which must call
854 * g_resolver_lookup_records_finish() to get the final result. See
855 * g_resolver_lookup_records() for more details.
856 *
857 * Since: 2.34
858 */
859 void
860 g_resolver_lookup_records_async (GResolver *resolver,
861 const gchar *rrname,
862 GResolverRecordType record_type,
863 GCancellable *cancellable,
864 GAsyncReadyCallback callback,
865 gpointer user_data)
866 {
867 g_return_if_fail (G_IS_RESOLVER (resolver));
868 g_return_if_fail (rrname != NULL);
869  
870 g_resolver_maybe_reload (resolver);
871 G_RESOLVER_GET_CLASS (resolver)->
872 lookup_records_async (resolver, rrname, record_type, cancellable, callback, user_data);
873 }
874  
875 /**
876 * g_resolver_lookup_records_finish:
877 * @resolver: a #GResolver
878 * @result: the result passed to your #GAsyncReadyCallback
879 * @error: return location for a #GError, or %NULL
880 *
881 * Retrieves the result of a previous call to
882 * g_resolver_lookup_records_async(). Returns a non-empty list of records as
883 * #GVariant tuples. See #GResolverRecordType for information on what the
884 * records contain.
885 *
886 * If the DNS resolution failed, @error (if non-%NULL) will be set to
887 * a value from #GResolverError. If the operation was cancelled,
888 * @error will be set to %G_IO_ERROR_CANCELLED.
889 *
890 * Returns: (element-type GVariant) (transfer full): a non-empty #GList of
891 * #GVariant, or %NULL on error. You must free each of the records and the list
892 * when you are done with it. (You can use g_list_free_full() with
893 * g_variant_unref() to do this.)
894 *
895 * Since: 2.34
896 */
897 GList *
898 g_resolver_lookup_records_finish (GResolver *resolver,
899 GAsyncResult *result,
900 GError **error)
901 {
902 g_return_val_if_fail (G_IS_RESOLVER (resolver), NULL);
903 return G_RESOLVER_GET_CLASS (resolver)->
904 lookup_records_finish (resolver, result, error);
905 }
906  
907 guint64
908 g_resolver_get_serial (GResolver *resolver)
909 {
910 g_return_val_if_fail (G_IS_RESOLVER (resolver), 0);
911  
912 g_resolver_maybe_reload (resolver);
913  
914 #ifdef G_OS_UNIX
915 return (guint64) resolver->priv->resolv_conf_timestamp;
916 #else
917 return 1;
918 #endif
919 }
920  
921 /**
922 * g_resolver_error_quark:
923 *
924 * Gets the #GResolver Error Quark.
925 *
926 * Returns: a #GQuark.
927 *
928 * Since: 2.22
929 */
930 G_DEFINE_QUARK (g-resolver-error-quark, g_resolver_error)