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 * Copyright (C) 2018 Igalia S.L.
7 *
8 * This library is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2.1 of the License, or (at your option) any later version.
12 *
13 * This library is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
17 *
18 * You should have received a copy of the GNU Lesser General
19 * Public License along with this library; if not, see <http://www.gnu.org/licenses/>.
20 */
21
22#include "config.h"
23#include <glib.h>
24#include "glibintl.h"
25
26#include "gresolver.h"
27#include "gnetworkingprivate.h"
28#include "gasyncresult.h"
29#include "ginetaddress.h"
30#include "gtask.h"
31#include "gsrvtarget.h"
32#include "gthreadedresolver.h"
33#include "gioerror.h"
34#include "gcancellable.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
58enum {
59 RELOAD,
60 LAST_SIGNAL
61};
62
63static guint signals[LAST_SIGNAL] = { 0 };
64
65struct _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 * This is an abstract type; subclasses of it implement different resolvers for
80 * different platforms and situations.
81 */
82G_DEFINE_ABSTRACT_TYPE_WITH_CODE (GResolver, g_resolver, G_TYPE_OBJECT,
83 G_ADD_PRIVATE (GResolver)
84 g_networking_init ();)
85
86static GList *
87srv_records_to_targets (GList *records)
88{
89 const gchar *hostname;
90 guint16 port, priority, weight;
91 GSrvTarget *target;
92 GList *l;
93
94 for (l = records; l != NULL; l = g_list_next (l))
95 {
96 g_variant_get (value: l->data, format_string: "(qqq&s)", &priority, &weight, &port, &hostname);
97 target = g_srv_target_new (hostname, port, priority, weight);
98 g_variant_unref (value: l->data);
99 l->data = target;
100 }
101
102 return g_srv_target_list_sort (targets: records);
103}
104
105static GList *
106g_resolver_real_lookup_service (GResolver *resolver,
107 const gchar *rrname,
108 GCancellable *cancellable,
109 GError **error)
110{
111 GList *records;
112
113 records = G_RESOLVER_GET_CLASS (resolver)->lookup_records (resolver,
114 rrname,
115 G_RESOLVER_RECORD_SRV,
116 cancellable,
117 error);
118
119 return srv_records_to_targets (records);
120}
121
122static void
123g_resolver_real_lookup_service_async (GResolver *resolver,
124 const gchar *rrname,
125 GCancellable *cancellable,
126 GAsyncReadyCallback callback,
127 gpointer user_data)
128{
129 G_RESOLVER_GET_CLASS (resolver)->lookup_records_async (resolver,
130 rrname,
131 G_RESOLVER_RECORD_SRV,
132 cancellable,
133 callback,
134 user_data);
135}
136
137static GList *
138g_resolver_real_lookup_service_finish (GResolver *resolver,
139 GAsyncResult *result,
140 GError **error)
141{
142 GList *records;
143
144 records = G_RESOLVER_GET_CLASS (resolver)->lookup_records_finish (resolver,
145 result,
146 error);
147
148 return srv_records_to_targets (records);
149}
150
151static void
152g_resolver_class_init (GResolverClass *resolver_class)
153{
154 /* Automatically pass these over to the lookup_records methods */
155 resolver_class->lookup_service = g_resolver_real_lookup_service;
156 resolver_class->lookup_service_async = g_resolver_real_lookup_service_async;
157 resolver_class->lookup_service_finish = g_resolver_real_lookup_service_finish;
158
159 /**
160 * GResolver::reload:
161 * @resolver: a #GResolver
162 *
163 * Emitted when the resolver notices that the system resolver
164 * configuration has changed.
165 **/
166 signals[RELOAD] =
167 g_signal_new (I_("reload"),
168 G_TYPE_RESOLVER,
169 signal_flags: G_SIGNAL_RUN_LAST,
170 G_STRUCT_OFFSET (GResolverClass, reload),
171 NULL, NULL,
172 NULL,
173 G_TYPE_NONE, n_params: 0);
174}
175
176static void
177g_resolver_init (GResolver *resolver)
178{
179#ifdef G_OS_UNIX
180 struct stat st;
181#endif
182
183 resolver->priv = g_resolver_get_instance_private (self: resolver);
184
185#ifdef G_OS_UNIX
186 if (stat (_PATH_RESCONF, buf: &st) == 0)
187 resolver->priv->resolv_conf_timestamp = st.st_mtime;
188#endif
189}
190
191G_LOCK_DEFINE_STATIC (default_resolver);
192static GResolver *default_resolver;
193
194/**
195 * g_resolver_get_default:
196 *
197 * Gets the default #GResolver. You should unref it when you are done
198 * with it. #GResolver may use its reference count as a hint about how
199 * many threads it should allocate for concurrent DNS resolutions.
200 *
201 * Returns: (transfer full): the default #GResolver.
202 *
203 * Since: 2.22
204 */
205GResolver *
206g_resolver_get_default (void)
207{
208 GResolver *ret;
209
210 G_LOCK (default_resolver);
211 if (!default_resolver)
212 default_resolver = g_object_new (G_TYPE_THREADED_RESOLVER, NULL);
213 ret = g_object_ref (default_resolver);
214 G_UNLOCK (default_resolver);
215
216 return ret;
217}
218
219/**
220 * g_resolver_set_default:
221 * @resolver: the new default #GResolver
222 *
223 * Sets @resolver to be the application's default resolver (reffing
224 * @resolver, and unreffing the previous default resolver, if any).
225 * Future calls to g_resolver_get_default() will return this resolver.
226 *
227 * This can be used if an application wants to perform any sort of DNS
228 * caching or "pinning"; it can implement its own #GResolver that
229 * calls the original default resolver for DNS operations, and
230 * implements its own cache policies on top of that, and then set
231 * itself as the default resolver for all later code to use.
232 *
233 * Since: 2.22
234 */
235void
236g_resolver_set_default (GResolver *resolver)
237{
238 G_LOCK (default_resolver);
239 if (default_resolver)
240 g_object_unref (object: default_resolver);
241 default_resolver = g_object_ref (resolver);
242 G_UNLOCK (default_resolver);
243}
244
245/* Bionic has res_init() but it's not in any header */
246#ifdef __BIONIC__
247int res_init (void);
248#endif
249
250static void
251g_resolver_maybe_reload (GResolver *resolver)
252{
253#ifdef G_OS_UNIX
254 struct stat st;
255
256 if (stat (_PATH_RESCONF, buf: &st) == 0)
257 {
258 if (st.st_mtime != resolver->priv->resolv_conf_timestamp)
259 {
260 resolver->priv->resolv_conf_timestamp = st.st_mtime;
261#ifdef HAVE_RES_INIT
262 res_init ();
263#endif
264 g_signal_emit (instance: resolver, signal_id: signals[RELOAD], detail: 0);
265 }
266 }
267#endif
268}
269
270/* filter out duplicates, cf. https://bugzilla.gnome.org/show_bug.cgi?id=631379 */
271static void
272remove_duplicates (GList *addrs)
273{
274 GList *l;
275 GList *ll;
276 GList *lll;
277
278 /* TODO: if this is too slow (it's O(n^2) but n is typically really
279 * small), we can do something more clever but note that we must not
280 * change the order of elements...
281 */
282 for (l = addrs; l != NULL; l = l->next)
283 {
284 GInetAddress *address = G_INET_ADDRESS (l->data);
285 for (ll = l->next; ll != NULL; ll = lll)
286 {
287 GInetAddress *other_address = G_INET_ADDRESS (ll->data);
288 lll = ll->next;
289 if (g_inet_address_equal (address, other_address))
290 {
291 g_object_unref (object: other_address);
292 /* we never return the first element */
293 g_warn_if_fail (g_list_delete_link (addrs, ll) == addrs);
294 }
295 }
296 }
297}
298
299static gboolean
300hostname_is_localhost (const char *hostname)
301{
302 size_t len = strlen (s: hostname);
303 const char *p;
304
305 /* Match "localhost", "localhost.", "*.localhost" and "*.localhost." */
306 if (len < strlen (s: "localhost"))
307 return FALSE;
308
309 if (hostname[len - 1] == '.')
310 len--;
311
312 /* Scan backwards in @hostname to find the right-most dot (excluding the final dot, if it exists, as it was chopped off above).
313 * We can’t use strrchr() because because we need to operate with string lengths.
314 * End with @p pointing to the character after the right-most dot. */
315 p = hostname + len - 1;
316 while (p >= hostname)
317 {
318 if (*p == '.')
319 {
320 p++;
321 break;
322 }
323 else if (p == hostname)
324 break;
325 p--;
326 }
327
328 len -= p - hostname;
329
330 return g_ascii_strncasecmp (s1: p, s2: "localhost", MAX (len, strlen ("localhost"))) == 0;
331}
332
333/* Note that this does not follow the "FALSE means @error is set"
334 * convention. The return value tells the caller whether it should
335 * return @addrs and @error to the caller right away, or if it should
336 * continue and trying to resolve the name as a hostname.
337 */
338static gboolean
339handle_ip_address_or_localhost (const char *hostname,
340 GList **addrs,
341 GResolverNameLookupFlags flags,
342 GError **error)
343{
344 GInetAddress *addr;
345
346#ifndef G_OS_WIN32
347 struct in_addr ip4addr;
348#endif
349
350 addr = g_inet_address_new_from_string (string: hostname);
351 if (addr)
352 {
353 *addrs = g_list_append (NULL, data: addr);
354 return TRUE;
355 }
356
357 *addrs = NULL;
358
359#ifdef G_OS_WIN32
360
361 /* Reject IPv6 addresses that have brackets ('[' or ']') and/or port numbers,
362 * as no valid addresses should contain these at this point.
363 * Non-standard IPv4 addresses would be rejected during the call to
364 * getaddrinfo() later.
365 */
366 if (strrchr (hostname, '[') != NULL ||
367 strrchr (hostname, ']') != NULL)
368#else
369
370 /* Reject non-standard IPv4 numbers-and-dots addresses.
371 * g_inet_address_new_from_string() will have accepted any "real" IP
372 * address, so if inet_aton() succeeds, then it's an address we want
373 * to reject.
374 */
375 if (inet_aton (cp: hostname, inp: &ip4addr))
376#endif
377 {
378#ifdef G_OS_WIN32
379 gchar *error_message = g_win32_error_message (WSAHOST_NOT_FOUND);
380#else
381 gchar *error_message = g_locale_to_utf8 (opsysstring: gai_strerror (EAI_NONAME), len: -1, NULL, NULL, NULL);
382 if (error_message == NULL)
383 error_message = g_strdup (str: "[Invalid UTF-8]");
384#endif
385 g_set_error (err: error, G_RESOLVER_ERROR, code: G_RESOLVER_ERROR_NOT_FOUND,
386 _("Error resolving “%s”: %s"),
387 hostname, error_message);
388 g_free (mem: error_message);
389
390 return TRUE;
391 }
392
393 /* Always resolve localhost to a loopback address so it can be reliably considered secure.
394 This behavior is being adopted by browsers:
395 - https://w3c.github.io/webappsec-secure-contexts/
396 - https://groups.google.com/a/chromium.org/forum/#!msg/blink-dev/RC9dSw-O3fE/E3_0XaT0BAAJ
397 - https://chromium.googlesource.com/chromium/src.git/+/8da2a80724a9b896890602ff77ef2216cb951399
398 - https://bugs.webkit.org/show_bug.cgi?id=171934
399 - https://tools.ietf.org/html/draft-west-let-localhost-be-localhost-06
400 */
401 if (hostname_is_localhost (hostname))
402 {
403 if (flags & G_RESOLVER_NAME_LOOKUP_FLAGS_IPV6_ONLY)
404 *addrs = g_list_append (list: *addrs, data: g_inet_address_new_loopback (family: G_SOCKET_FAMILY_IPV6));
405 if (flags & G_RESOLVER_NAME_LOOKUP_FLAGS_IPV4_ONLY)
406 *addrs = g_list_append (list: *addrs, data: g_inet_address_new_loopback (family: G_SOCKET_FAMILY_IPV4));
407 if (*addrs == NULL)
408 {
409 *addrs = g_list_append (list: *addrs, data: g_inet_address_new_loopback (family: G_SOCKET_FAMILY_IPV6));
410 *addrs = g_list_append (list: *addrs, data: g_inet_address_new_loopback (family: G_SOCKET_FAMILY_IPV4));
411 }
412 return TRUE;
413 }
414
415 return FALSE;
416}
417
418static GList *
419lookup_by_name_real (GResolver *resolver,
420 const gchar *hostname,
421 GResolverNameLookupFlags flags,
422 GCancellable *cancellable,
423 GError **error)
424{
425 GList *addrs;
426 gchar *ascii_hostname = NULL;
427
428 g_return_val_if_fail (G_IS_RESOLVER (resolver), NULL);
429 g_return_val_if_fail (hostname != NULL, NULL);
430 g_return_val_if_fail (cancellable == NULL || G_IS_CANCELLABLE (cancellable), NULL);
431 g_return_val_if_fail (error == NULL || *error == NULL, NULL);
432
433 /* Check if @hostname is just an IP address */
434 if (handle_ip_address_or_localhost (hostname, addrs: &addrs, flags, error))
435 return addrs;
436
437 if (g_hostname_is_non_ascii (hostname))
438 hostname = ascii_hostname = g_hostname_to_ascii (hostname);
439
440 if (!hostname)
441 {
442 g_set_error_literal (err: error, G_IO_ERROR, code: G_IO_ERROR_FAILED,
443 _("Invalid hostname"));
444 return NULL;
445 }
446
447 g_resolver_maybe_reload (resolver);
448
449 if (flags != G_RESOLVER_NAME_LOOKUP_FLAGS_DEFAULT)
450 {
451 if (!G_RESOLVER_GET_CLASS (resolver)->lookup_by_name_with_flags)
452 {
453 g_set_error (err: error, G_IO_ERROR, code: G_IO_ERROR_NOT_SUPPORTED,
454 /* Translators: The placeholder is for a function name. */
455 _("%s not implemented"), "lookup_by_name_with_flags");
456 g_free (mem: ascii_hostname);
457 return NULL;
458 }
459 addrs = G_RESOLVER_GET_CLASS (resolver)->
460 lookup_by_name_with_flags (resolver, hostname, flags, cancellable, error);
461 }
462 else
463 addrs = G_RESOLVER_GET_CLASS (resolver)->
464 lookup_by_name (resolver, hostname, cancellable, error);
465
466 remove_duplicates (addrs);
467
468 g_free (mem: ascii_hostname);
469 return addrs;
470}
471
472/**
473 * g_resolver_lookup_by_name:
474 * @resolver: a #GResolver
475 * @hostname: the hostname to look up
476 * @cancellable: (nullable): a #GCancellable, or %NULL
477 * @error: return location for a #GError, or %NULL
478 *
479 * Synchronously resolves @hostname to determine its associated IP
480 * address(es). @hostname may be an ASCII-only or UTF-8 hostname, or
481 * the textual form of an IP address (in which case this just becomes
482 * a wrapper around g_inet_address_new_from_string()).
483 *
484 * On success, g_resolver_lookup_by_name() will return a non-empty #GList of
485 * #GInetAddress, sorted in order of preference and guaranteed to not
486 * contain duplicates. That is, if using the result to connect to
487 * @hostname, you should attempt to connect to the first address
488 * first, then the second if the first fails, etc. If you are using
489 * the result to listen on a socket, it is appropriate to add each
490 * result using e.g. g_socket_listener_add_address().
491 *
492 * If the DNS resolution fails, @error (if non-%NULL) will be set to a
493 * value from #GResolverError and %NULL will be returned.
494 *
495 * If @cancellable is non-%NULL, it can be used to cancel the
496 * operation, in which case @error (if non-%NULL) will be set to
497 * %G_IO_ERROR_CANCELLED.
498 *
499 * If you are planning to connect to a socket on the resolved IP
500 * address, it may be easier to create a #GNetworkAddress and use its
501 * #GSocketConnectable interface.
502 *
503 * Returns: (element-type GInetAddress) (transfer full): a non-empty #GList
504 * of #GInetAddress, or %NULL on error. You
505 * must unref each of the addresses and free the list when you are
506 * done with it. (You can use g_resolver_free_addresses() to do this.)
507 *
508 * Since: 2.22
509 */
510GList *
511g_resolver_lookup_by_name (GResolver *resolver,
512 const gchar *hostname,
513 GCancellable *cancellable,
514 GError **error)
515{
516 return lookup_by_name_real (resolver,
517 hostname,
518 flags: G_RESOLVER_NAME_LOOKUP_FLAGS_DEFAULT,
519 cancellable,
520 error);
521}
522
523/**
524 * g_resolver_lookup_by_name_with_flags:
525 * @resolver: a #GResolver
526 * @hostname: the hostname to look up
527 * @flags: extra #GResolverNameLookupFlags for the lookup
528 * @cancellable: (nullable): a #GCancellable, or %NULL
529 * @error: (nullable): return location for a #GError, or %NULL
530 *
531 * This differs from g_resolver_lookup_by_name() in that you can modify
532 * the lookup behavior with @flags. For example this can be used to limit
533 * results with #G_RESOLVER_NAME_LOOKUP_FLAGS_IPV4_ONLY.
534 *
535 * Returns: (element-type GInetAddress) (transfer full): a non-empty #GList
536 * of #GInetAddress, or %NULL on error. You
537 * must unref each of the addresses and free the list when you are
538 * done with it. (You can use g_resolver_free_addresses() to do this.)
539 *
540 * Since: 2.60
541 */
542GList *
543g_resolver_lookup_by_name_with_flags (GResolver *resolver,
544 const gchar *hostname,
545 GResolverNameLookupFlags flags,
546 GCancellable *cancellable,
547 GError **error)
548{
549 return lookup_by_name_real (resolver,
550 hostname,
551 flags,
552 cancellable,
553 error);
554}
555
556static void
557lookup_by_name_async_real (GResolver *resolver,
558 const gchar *hostname,
559 GResolverNameLookupFlags flags,
560 GCancellable *cancellable,
561 GAsyncReadyCallback callback,
562 gpointer user_data)
563{
564 gchar *ascii_hostname = NULL;
565 GList *addrs;
566 GError *error = NULL;
567
568 g_return_if_fail (G_IS_RESOLVER (resolver));
569 g_return_if_fail (hostname != NULL);
570 g_return_if_fail (!(flags & G_RESOLVER_NAME_LOOKUP_FLAGS_IPV4_ONLY && flags & G_RESOLVER_NAME_LOOKUP_FLAGS_IPV6_ONLY));
571
572 /* Check if @hostname is just an IP address */
573 if (handle_ip_address_or_localhost (hostname, addrs: &addrs, flags, error: &error))
574 {
575 GTask *task;
576
577 task = g_task_new (source_object: resolver, cancellable, callback, callback_data: user_data);
578 g_task_set_source_tag (task, lookup_by_name_async_real);
579 g_task_set_name (task, name: "[gio] resolver lookup");
580 if (addrs)
581 g_task_return_pointer (task, result: addrs, result_destroy: (GDestroyNotify) g_resolver_free_addresses);
582 else
583 g_task_return_error (task, error);
584 g_object_unref (object: task);
585 return;
586 }
587
588 if (g_hostname_is_non_ascii (hostname))
589 hostname = ascii_hostname = g_hostname_to_ascii (hostname);
590
591 if (!hostname)
592 {
593 GTask *task;
594
595 g_set_error_literal (err: &error, G_IO_ERROR, code: G_IO_ERROR_FAILED,
596 _("Invalid hostname"));
597 task = g_task_new (source_object: resolver, cancellable, callback, callback_data: user_data);
598 g_task_set_source_tag (task, lookup_by_name_async_real);
599 g_task_set_name (task, name: "[gio] resolver lookup");
600 g_task_return_error (task, error);
601 g_object_unref (object: task);
602 return;
603 }
604
605 g_resolver_maybe_reload (resolver);
606
607 if (flags != G_RESOLVER_NAME_LOOKUP_FLAGS_DEFAULT)
608 {
609 if (G_RESOLVER_GET_CLASS (resolver)->lookup_by_name_with_flags_async == NULL)
610 {
611 GTask *task;
612
613 g_set_error (err: &error, G_IO_ERROR, code: G_IO_ERROR_NOT_SUPPORTED,
614 /* Translators: The placeholder is for a function name. */
615 _("%s not implemented"), "lookup_by_name_with_flags_async");
616 task = g_task_new (source_object: resolver, cancellable, callback, callback_data: user_data);
617 g_task_set_source_tag (task, lookup_by_name_async_real);
618 g_task_set_name (task, name: "[gio] resolver lookup");
619 g_task_return_error (task, error);
620 g_object_unref (object: task);
621 }
622 else
623 G_RESOLVER_GET_CLASS (resolver)->
624 lookup_by_name_with_flags_async (resolver, hostname, flags, cancellable, callback, user_data);
625 }
626 else
627 G_RESOLVER_GET_CLASS (resolver)->
628 lookup_by_name_async (resolver, hostname, cancellable, callback, user_data);
629
630 g_free (mem: ascii_hostname);
631}
632
633static GList *
634lookup_by_name_finish_real (GResolver *resolver,
635 GAsyncResult *result,
636 GError **error,
637 gboolean with_flags)
638{
639 GList *addrs;
640
641 g_return_val_if_fail (G_IS_RESOLVER (resolver), NULL);
642 g_return_val_if_fail (G_IS_ASYNC_RESULT (result), NULL);
643 g_return_val_if_fail (error == NULL || *error == NULL, NULL);
644
645 if (g_async_result_legacy_propagate_error (res: result, error))
646 return NULL;
647 else if (g_async_result_is_tagged (res: result, source_tag: lookup_by_name_async_real))
648 {
649 /* Handle the stringified-IP-addr case */
650 return g_task_propagate_pointer (G_TASK (result), error);
651 }
652
653 if (with_flags)
654 {
655 g_assert (G_RESOLVER_GET_CLASS (resolver)->lookup_by_name_with_flags_finish != NULL);
656 addrs = G_RESOLVER_GET_CLASS (resolver)->
657 lookup_by_name_with_flags_finish (resolver, result, error);
658 }
659 else
660 addrs = G_RESOLVER_GET_CLASS (resolver)->
661 lookup_by_name_finish (resolver, result, error);
662
663 remove_duplicates (addrs);
664
665 return addrs;
666}
667
668/**
669 * g_resolver_lookup_by_name_with_flags_async:
670 * @resolver: a #GResolver
671 * @hostname: the hostname to look up the address of
672 * @flags: extra #GResolverNameLookupFlags for the lookup
673 * @cancellable: (nullable): a #GCancellable, or %NULL
674 * @callback: (scope async): callback to call after resolution completes
675 * @user_data: (closure): data for @callback
676 *
677 * Begins asynchronously resolving @hostname to determine its
678 * associated IP address(es), and eventually calls @callback, which
679 * must call g_resolver_lookup_by_name_with_flags_finish() to get the result.
680 * See g_resolver_lookup_by_name() for more details.
681 *
682 * Since: 2.60
683 */
684void
685g_resolver_lookup_by_name_with_flags_async (GResolver *resolver,
686 const gchar *hostname,
687 GResolverNameLookupFlags flags,
688 GCancellable *cancellable,
689 GAsyncReadyCallback callback,
690 gpointer user_data)
691{
692 lookup_by_name_async_real (resolver,
693 hostname,
694 flags,
695 cancellable,
696 callback,
697 user_data);
698}
699
700/**
701 * g_resolver_lookup_by_name_async:
702 * @resolver: a #GResolver
703 * @hostname: the hostname to look up the address of
704 * @cancellable: (nullable): a #GCancellable, or %NULL
705 * @callback: (scope async): callback to call after resolution completes
706 * @user_data: (closure): data for @callback
707 *
708 * Begins asynchronously resolving @hostname to determine its
709 * associated IP address(es), and eventually calls @callback, which
710 * must call g_resolver_lookup_by_name_finish() to get the result.
711 * See g_resolver_lookup_by_name() for more details.
712 *
713 * Since: 2.22
714 */
715void
716g_resolver_lookup_by_name_async (GResolver *resolver,
717 const gchar *hostname,
718 GCancellable *cancellable,
719 GAsyncReadyCallback callback,
720 gpointer user_data)
721{
722 lookup_by_name_async_real (resolver,
723 hostname,
724 flags: 0,
725 cancellable,
726 callback,
727 user_data);
728}
729
730/**
731 * g_resolver_lookup_by_name_finish:
732 * @resolver: a #GResolver
733 * @result: the result passed to your #GAsyncReadyCallback
734 * @error: return location for a #GError, or %NULL
735 *
736 * Retrieves the result of a call to
737 * g_resolver_lookup_by_name_async().
738 *
739 * If the DNS resolution failed, @error (if non-%NULL) will be set to
740 * a value from #GResolverError. If the operation was cancelled,
741 * @error will be set to %G_IO_ERROR_CANCELLED.
742 *
743 * Returns: (element-type GInetAddress) (transfer full): a #GList
744 * of #GInetAddress, or %NULL on error. See g_resolver_lookup_by_name()
745 * for more details.
746 *
747 * Since: 2.22
748 */
749GList *
750g_resolver_lookup_by_name_finish (GResolver *resolver,
751 GAsyncResult *result,
752 GError **error)
753{
754 return lookup_by_name_finish_real (resolver,
755 result,
756 error,
757 FALSE);
758}
759
760/**
761 * g_resolver_lookup_by_name_with_flags_finish:
762 * @resolver: a #GResolver
763 * @result: the result passed to your #GAsyncReadyCallback
764 * @error: return location for a #GError, or %NULL
765 *
766 * Retrieves the result of a call to
767 * g_resolver_lookup_by_name_with_flags_async().
768 *
769 * If the DNS resolution failed, @error (if non-%NULL) will be set to
770 * a value from #GResolverError. If the operation was cancelled,
771 * @error will be set to %G_IO_ERROR_CANCELLED.
772 *
773 * Returns: (element-type GInetAddress) (transfer full): a #GList
774 * of #GInetAddress, or %NULL on error. See g_resolver_lookup_by_name()
775 * for more details.
776 *
777 * Since: 2.60
778 */
779GList *
780g_resolver_lookup_by_name_with_flags_finish (GResolver *resolver,
781 GAsyncResult *result,
782 GError **error)
783{
784 return lookup_by_name_finish_real (resolver,
785 result,
786 error,
787 TRUE);
788}
789
790/**
791 * g_resolver_free_addresses: (skip)
792 * @addresses: a #GList of #GInetAddress
793 *
794 * Frees @addresses (which should be the return value from
795 * g_resolver_lookup_by_name() or g_resolver_lookup_by_name_finish()).
796 * (This is a convenience method; you can also simply free the results
797 * by hand.)
798 *
799 * Since: 2.22
800 */
801void
802g_resolver_free_addresses (GList *addresses)
803{
804 GList *a;
805
806 for (a = addresses; a; a = a->next)
807 g_object_unref (object: a->data);
808 g_list_free (list: addresses);
809}
810
811/**
812 * g_resolver_lookup_by_address:
813 * @resolver: a #GResolver
814 * @address: the address to reverse-resolve
815 * @cancellable: (nullable): a #GCancellable, or %NULL
816 * @error: return location for a #GError, or %NULL
817 *
818 * Synchronously reverse-resolves @address to determine its
819 * associated hostname.
820 *
821 * If the DNS resolution fails, @error (if non-%NULL) will be set to
822 * a value from #GResolverError.
823 *
824 * If @cancellable is non-%NULL, it can be used to cancel the
825 * operation, in which case @error (if non-%NULL) will be set to
826 * %G_IO_ERROR_CANCELLED.
827 *
828 * Returns: a hostname (either ASCII-only, or in ASCII-encoded
829 * form), or %NULL on error.
830 *
831 * Since: 2.22
832 */
833gchar *
834g_resolver_lookup_by_address (GResolver *resolver,
835 GInetAddress *address,
836 GCancellable *cancellable,
837 GError **error)
838{
839 g_return_val_if_fail (G_IS_RESOLVER (resolver), NULL);
840 g_return_val_if_fail (G_IS_INET_ADDRESS (address), NULL);
841
842 g_resolver_maybe_reload (resolver);
843 return G_RESOLVER_GET_CLASS (resolver)->
844 lookup_by_address (resolver, address, cancellable, error);
845}
846
847/**
848 * g_resolver_lookup_by_address_async:
849 * @resolver: a #GResolver
850 * @address: the address to reverse-resolve
851 * @cancellable: (nullable): a #GCancellable, or %NULL
852 * @callback: (scope async): callback to call after resolution completes
853 * @user_data: (closure): data for @callback
854 *
855 * Begins asynchronously reverse-resolving @address to determine its
856 * associated hostname, and eventually calls @callback, which must
857 * call g_resolver_lookup_by_address_finish() to get the final result.
858 *
859 * Since: 2.22
860 */
861void
862g_resolver_lookup_by_address_async (GResolver *resolver,
863 GInetAddress *address,
864 GCancellable *cancellable,
865 GAsyncReadyCallback callback,
866 gpointer user_data)
867{
868 g_return_if_fail (G_IS_RESOLVER (resolver));
869 g_return_if_fail (G_IS_INET_ADDRESS (address));
870
871 g_resolver_maybe_reload (resolver);
872 G_RESOLVER_GET_CLASS (resolver)->
873 lookup_by_address_async (resolver, address, cancellable, callback, user_data);
874}
875
876/**
877 * g_resolver_lookup_by_address_finish:
878 * @resolver: a #GResolver
879 * @result: the result passed to your #GAsyncReadyCallback
880 * @error: return location for a #GError, or %NULL
881 *
882 * Retrieves the result of a previous call to
883 * g_resolver_lookup_by_address_async().
884 *
885 * If the DNS resolution failed, @error (if non-%NULL) will be set to
886 * a value from #GResolverError. If the operation was cancelled,
887 * @error will be set to %G_IO_ERROR_CANCELLED.
888 *
889 * Returns: a hostname (either ASCII-only, or in ASCII-encoded
890 * form), or %NULL on error.
891 *
892 * Since: 2.22
893 */
894gchar *
895g_resolver_lookup_by_address_finish (GResolver *resolver,
896 GAsyncResult *result,
897 GError **error)
898{
899 g_return_val_if_fail (G_IS_RESOLVER (resolver), NULL);
900
901 if (g_async_result_legacy_propagate_error (res: result, error))
902 return NULL;
903
904 return G_RESOLVER_GET_CLASS (resolver)->
905 lookup_by_address_finish (resolver, result, error);
906}
907
908static gchar *
909g_resolver_get_service_rrname (const char *service,
910 const char *protocol,
911 const char *domain)
912{
913 gchar *rrname, *ascii_domain = NULL;
914
915 if (g_hostname_is_non_ascii (hostname: domain))
916 domain = ascii_domain = g_hostname_to_ascii (hostname: domain);
917 if (!domain)
918 return NULL;
919
920 rrname = g_strdup_printf (format: "_%s._%s.%s", service, protocol, domain);
921
922 g_free (mem: ascii_domain);
923 return rrname;
924}
925
926/**
927 * g_resolver_lookup_service:
928 * @resolver: a #GResolver
929 * @service: the service type to look up (eg, "ldap")
930 * @protocol: the networking protocol to use for @service (eg, "tcp")
931 * @domain: the DNS domain to look up the service in
932 * @cancellable: (nullable): a #GCancellable, or %NULL
933 * @error: return location for a #GError, or %NULL
934 *
935 * Synchronously performs a DNS SRV lookup for the given @service and
936 * @protocol in the given @domain and returns an array of #GSrvTarget.
937 * @domain may be an ASCII-only or UTF-8 hostname. Note also that the
938 * @service and @protocol arguments do not include the leading underscore
939 * that appears in the actual DNS entry.
940 *
941 * On success, g_resolver_lookup_service() will return a non-empty #GList of
942 * #GSrvTarget, sorted in order of preference. (That is, you should
943 * attempt to connect to the first target first, then the second if
944 * the first fails, etc.)
945 *
946 * If the DNS resolution fails, @error (if non-%NULL) will be set to
947 * a value from #GResolverError and %NULL will be returned.
948 *
949 * If @cancellable is non-%NULL, it can be used to cancel the
950 * operation, in which case @error (if non-%NULL) will be set to
951 * %G_IO_ERROR_CANCELLED.
952 *
953 * If you are planning to connect to the service, it is usually easier
954 * to create a #GNetworkService and use its #GSocketConnectable
955 * interface.
956 *
957 * Returns: (element-type GSrvTarget) (transfer full): a non-empty #GList of
958 * #GSrvTarget, or %NULL on error. You must free each of the targets and the
959 * list when you are done with it. (You can use g_resolver_free_targets() to do
960 * this.)
961 *
962 * Since: 2.22
963 */
964GList *
965g_resolver_lookup_service (GResolver *resolver,
966 const gchar *service,
967 const gchar *protocol,
968 const gchar *domain,
969 GCancellable *cancellable,
970 GError **error)
971{
972 GList *targets;
973 gchar *rrname;
974
975 g_return_val_if_fail (G_IS_RESOLVER (resolver), NULL);
976 g_return_val_if_fail (service != NULL, NULL);
977 g_return_val_if_fail (protocol != NULL, NULL);
978 g_return_val_if_fail (domain != NULL, NULL);
979
980 rrname = g_resolver_get_service_rrname (service, protocol, domain);
981 if (!rrname)
982 {
983 g_set_error_literal (err: error, G_IO_ERROR, code: G_IO_ERROR_FAILED,
984 _("Invalid domain"));
985 return NULL;
986 }
987
988 g_resolver_maybe_reload (resolver);
989 targets = G_RESOLVER_GET_CLASS (resolver)->
990 lookup_service (resolver, rrname, cancellable, error);
991
992 g_free (mem: rrname);
993 return targets;
994}
995
996/**
997 * g_resolver_lookup_service_async:
998 * @resolver: a #GResolver
999 * @service: the service type to look up (eg, "ldap")
1000 * @protocol: the networking protocol to use for @service (eg, "tcp")
1001 * @domain: the DNS domain to look up the service in
1002 * @cancellable: (nullable): a #GCancellable, or %NULL
1003 * @callback: (scope async): callback to call after resolution completes
1004 * @user_data: (closure): data for @callback
1005 *
1006 * Begins asynchronously performing a DNS SRV lookup for the given
1007 * @service and @protocol in the given @domain, and eventually calls
1008 * @callback, which must call g_resolver_lookup_service_finish() to
1009 * get the final result. See g_resolver_lookup_service() for more
1010 * details.
1011 *
1012 * Since: 2.22
1013 */
1014void
1015g_resolver_lookup_service_async (GResolver *resolver,
1016 const gchar *service,
1017 const gchar *protocol,
1018 const gchar *domain,
1019 GCancellable *cancellable,
1020 GAsyncReadyCallback callback,
1021 gpointer user_data)
1022{
1023 gchar *rrname;
1024
1025 g_return_if_fail (G_IS_RESOLVER (resolver));
1026 g_return_if_fail (service != NULL);
1027 g_return_if_fail (protocol != NULL);
1028 g_return_if_fail (domain != NULL);
1029
1030 rrname = g_resolver_get_service_rrname (service, protocol, domain);
1031 if (!rrname)
1032 {
1033 g_task_report_new_error (source_object: resolver, callback, callback_data: user_data,
1034 source_tag: g_resolver_lookup_service_async,
1035 G_IO_ERROR, code: G_IO_ERROR_FAILED,
1036 _("Invalid domain"));
1037 return;
1038 }
1039
1040 g_resolver_maybe_reload (resolver);
1041 G_RESOLVER_GET_CLASS (resolver)->
1042 lookup_service_async (resolver, rrname, cancellable, callback, user_data);
1043
1044 g_free (mem: rrname);
1045}
1046
1047/**
1048 * g_resolver_lookup_service_finish:
1049 * @resolver: a #GResolver
1050 * @result: the result passed to your #GAsyncReadyCallback
1051 * @error: return location for a #GError, or %NULL
1052 *
1053 * Retrieves the result of a previous call to
1054 * g_resolver_lookup_service_async().
1055 *
1056 * If the DNS resolution failed, @error (if non-%NULL) will be set to
1057 * a value from #GResolverError. If the operation was cancelled,
1058 * @error will be set to %G_IO_ERROR_CANCELLED.
1059 *
1060 * Returns: (element-type GSrvTarget) (transfer full): a non-empty #GList of
1061 * #GSrvTarget, or %NULL on error. See g_resolver_lookup_service() for more
1062 * details.
1063 *
1064 * Since: 2.22
1065 */
1066GList *
1067g_resolver_lookup_service_finish (GResolver *resolver,
1068 GAsyncResult *result,
1069 GError **error)
1070{
1071 g_return_val_if_fail (G_IS_RESOLVER (resolver), NULL);
1072
1073 if (g_async_result_legacy_propagate_error (res: result, error))
1074 return NULL;
1075
1076 return G_RESOLVER_GET_CLASS (resolver)->
1077 lookup_service_finish (resolver, result, error);
1078}
1079
1080/**
1081 * g_resolver_free_targets: (skip)
1082 * @targets: a #GList of #GSrvTarget
1083 *
1084 * Frees @targets (which should be the return value from
1085 * g_resolver_lookup_service() or g_resolver_lookup_service_finish()).
1086 * (This is a convenience method; you can also simply free the
1087 * results by hand.)
1088 *
1089 * Since: 2.22
1090 */
1091void
1092g_resolver_free_targets (GList *targets)
1093{
1094 GList *t;
1095
1096 for (t = targets; t; t = t->next)
1097 g_srv_target_free (target: t->data);
1098 g_list_free (list: targets);
1099}
1100
1101/**
1102 * g_resolver_lookup_records:
1103 * @resolver: a #GResolver
1104 * @rrname: the DNS name to look up the record for
1105 * @record_type: the type of DNS record to look up
1106 * @cancellable: (nullable): a #GCancellable, or %NULL
1107 * @error: return location for a #GError, or %NULL
1108 *
1109 * Synchronously performs a DNS record lookup for the given @rrname and returns
1110 * a list of records as #GVariant tuples. See #GResolverRecordType for
1111 * information on what the records contain for each @record_type.
1112 *
1113 * If the DNS resolution fails, @error (if non-%NULL) will be set to
1114 * a value from #GResolverError and %NULL will be returned.
1115 *
1116 * If @cancellable is non-%NULL, it can be used to cancel the
1117 * operation, in which case @error (if non-%NULL) will be set to
1118 * %G_IO_ERROR_CANCELLED.
1119 *
1120 * Returns: (element-type GVariant) (transfer full): a non-empty #GList of
1121 * #GVariant, or %NULL on error. You must free each of the records and the list
1122 * when you are done with it. (You can use g_list_free_full() with
1123 * g_variant_unref() to do this.)
1124 *
1125 * Since: 2.34
1126 */
1127GList *
1128g_resolver_lookup_records (GResolver *resolver,
1129 const gchar *rrname,
1130 GResolverRecordType record_type,
1131 GCancellable *cancellable,
1132 GError **error)
1133{
1134 GList *records;
1135
1136 g_return_val_if_fail (G_IS_RESOLVER (resolver), NULL);
1137 g_return_val_if_fail (rrname != NULL, NULL);
1138
1139 g_resolver_maybe_reload (resolver);
1140 records = G_RESOLVER_GET_CLASS (resolver)->
1141 lookup_records (resolver, rrname, record_type, cancellable, error);
1142
1143 return records;
1144}
1145
1146/**
1147 * g_resolver_lookup_records_async:
1148 * @resolver: a #GResolver
1149 * @rrname: the DNS name to look up the record for
1150 * @record_type: the type of DNS record to look up
1151 * @cancellable: (nullable): a #GCancellable, or %NULL
1152 * @callback: (scope async): callback to call after resolution completes
1153 * @user_data: (closure): data for @callback
1154 *
1155 * Begins asynchronously performing a DNS lookup for the given
1156 * @rrname, and eventually calls @callback, which must call
1157 * g_resolver_lookup_records_finish() to get the final result. See
1158 * g_resolver_lookup_records() for more details.
1159 *
1160 * Since: 2.34
1161 */
1162void
1163g_resolver_lookup_records_async (GResolver *resolver,
1164 const gchar *rrname,
1165 GResolverRecordType record_type,
1166 GCancellable *cancellable,
1167 GAsyncReadyCallback callback,
1168 gpointer user_data)
1169{
1170 g_return_if_fail (G_IS_RESOLVER (resolver));
1171 g_return_if_fail (rrname != NULL);
1172
1173 g_resolver_maybe_reload (resolver);
1174 G_RESOLVER_GET_CLASS (resolver)->
1175 lookup_records_async (resolver, rrname, record_type, cancellable, callback, user_data);
1176}
1177
1178/**
1179 * g_resolver_lookup_records_finish:
1180 * @resolver: a #GResolver
1181 * @result: the result passed to your #GAsyncReadyCallback
1182 * @error: return location for a #GError, or %NULL
1183 *
1184 * Retrieves the result of a previous call to
1185 * g_resolver_lookup_records_async(). Returns a non-empty list of records as
1186 * #GVariant tuples. See #GResolverRecordType for information on what the
1187 * records contain.
1188 *
1189 * If the DNS resolution failed, @error (if non-%NULL) will be set to
1190 * a value from #GResolverError. If the operation was cancelled,
1191 * @error will be set to %G_IO_ERROR_CANCELLED.
1192 *
1193 * Returns: (element-type GVariant) (transfer full): a non-empty #GList of
1194 * #GVariant, or %NULL on error. You must free each of the records and the list
1195 * when you are done with it. (You can use g_list_free_full() with
1196 * g_variant_unref() to do this.)
1197 *
1198 * Since: 2.34
1199 */
1200GList *
1201g_resolver_lookup_records_finish (GResolver *resolver,
1202 GAsyncResult *result,
1203 GError **error)
1204{
1205 g_return_val_if_fail (G_IS_RESOLVER (resolver), NULL);
1206 return G_RESOLVER_GET_CLASS (resolver)->
1207 lookup_records_finish (resolver, result, error);
1208}
1209
1210guint64
1211g_resolver_get_serial (GResolver *resolver)
1212{
1213 g_return_val_if_fail (G_IS_RESOLVER (resolver), 0);
1214
1215 g_resolver_maybe_reload (resolver);
1216
1217#ifdef G_OS_UNIX
1218 return (guint64) resolver->priv->resolv_conf_timestamp;
1219#else
1220 return 1;
1221#endif
1222}
1223
1224/**
1225 * g_resolver_error_quark:
1226 *
1227 * Gets the #GResolver Error Quark.
1228 *
1229 * Returns: a #GQuark.
1230 *
1231 * Since: 2.22
1232 */
1233G_DEFINE_QUARK (g-resolver-error-quark, g_resolver_error)
1234

source code of gtk/subprojects/glib/gio/gresolver.c