/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */ /* GIO - GLib Input, Output and Streaming Library * * Copyright (C) 2008 Red Hat, Inc. * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General * Public License along with this library; if not, write to the * Free Software Foundation, Inc., 59 Temple Place, Suite 330, * Boston, MA 02111-1307, USA. */ #include "config.h" #include #include "glibintl.h" #include "gresolver.h" #include "gnetworkingprivate.h" #include "gasyncresult.h" #include "ginetaddress.h" #include "gsimpleasyncresult.h" #include "gtask.h" #include "gsrvtarget.h" #include "gthreadedresolver.h" #ifdef G_OS_UNIX #include #endif #include /** * SECTION:gresolver * @short_description: Asynchronous and cancellable DNS resolver * @include: gio/gio.h * * #GResolver provides cancellable synchronous and asynchronous DNS * resolution, for hostnames (g_resolver_lookup_by_address(), * g_resolver_lookup_by_name() and their async variants) and SRV * (service) records (g_resolver_lookup_service()). * * #GNetworkAddress and #GNetworkService provide wrappers around * #GResolver functionality that also implement #GSocketConnectable, * making it easy to connect to a remote host/service. */ enum { RELOAD, LAST_SIGNAL }; static guint signals[LAST_SIGNAL] = { 0 }; struct _GResolverPrivate { #ifdef G_OS_UNIX time_t resolv_conf_timestamp; #else int dummy; #endif }; /** * GResolver: * * The object that handles DNS resolution. Use g_resolver_get_default() * to get the default resolver. */ G_DEFINE_TYPE_WITH_CODE (GResolver, g_resolver, G_TYPE_OBJECT, g_networking_init ();) static GList * srv_records_to_targets (GList *records) { const gchar *hostname; guint16 port, priority, weight; GSrvTarget *target; GList *l; for (l = records; l != NULL; l = g_list_next (l)) { g_variant_get (l->data, "(qqq&s)", &priority, &weight, &port, &hostname); target = g_srv_target_new (hostname, port, priority, weight); g_variant_unref (l->data); l->data = target; } return g_srv_target_list_sort (records); } static GList * g_resolver_real_lookup_service (GResolver *resolver, const gchar *rrname, GCancellable *cancellable, GError **error) { GList *records; records = G_RESOLVER_GET_CLASS (resolver)->lookup_records (resolver, rrname, G_RESOLVER_RECORD_SRV, cancellable, error); return srv_records_to_targets (records); } static void g_resolver_real_lookup_service_async (GResolver *resolver, const gchar *rrname, GCancellable *cancellable, GAsyncReadyCallback callback, gpointer user_data) { G_RESOLVER_GET_CLASS (resolver)->lookup_records_async (resolver, rrname, G_RESOLVER_RECORD_SRV, cancellable, callback, user_data); } static GList * g_resolver_real_lookup_service_finish (GResolver *resolver, GAsyncResult *result, GError **error) { GList *records; records = G_RESOLVER_GET_CLASS (resolver)->lookup_records_finish (resolver, result, error); return srv_records_to_targets (records); } static void g_resolver_class_init (GResolverClass *resolver_class) { /* Automatically pass these over to the lookup_records methods */ resolver_class->lookup_service = g_resolver_real_lookup_service; resolver_class->lookup_service_async = g_resolver_real_lookup_service_async; resolver_class->lookup_service_finish = g_resolver_real_lookup_service_finish; g_type_class_add_private (resolver_class, sizeof (GResolverPrivate)); /** * GResolver::reload: * @resolver: a #GResolver * * Emitted when the resolver notices that the system resolver * configuration has changed. **/ signals[RELOAD] = g_signal_new (I_("reload"), G_TYPE_RESOLVER, G_SIGNAL_RUN_LAST, G_STRUCT_OFFSET (GResolverClass, reload), NULL, NULL, g_cclosure_marshal_VOID__VOID, G_TYPE_NONE, 0); } static void g_resolver_init (GResolver *resolver) { #ifdef G_OS_UNIX struct stat st; #endif resolver->priv = G_TYPE_INSTANCE_GET_PRIVATE (resolver, G_TYPE_RESOLVER, GResolverPrivate); #ifdef G_OS_UNIX if (stat (_PATH_RESCONF, &st) == 0) resolver->priv->resolv_conf_timestamp = st.st_mtime; #endif } static GResolver *default_resolver; /** * g_resolver_get_default: * * Gets the default #GResolver. You should unref it when you are done * with it. #GResolver may use its reference count as a hint about how * many threads it should allocate for concurrent DNS resolutions. * * Return value: (transfer full): the default #GResolver. * * Since: 2.22 */ GResolver * g_resolver_get_default (void) { if (!default_resolver) default_resolver = g_object_new (G_TYPE_THREADED_RESOLVER, NULL); return g_object_ref (default_resolver); } /** * g_resolver_set_default: * @resolver: the new default #GResolver * * Sets @resolver to be the application's default resolver (reffing * @resolver, and unreffing the previous default resolver, if any). * Future calls to g_resolver_get_default() will return this resolver. * * This can be used if an application wants to perform any sort of DNS * caching or "pinning"; it can implement its own #GResolver that * calls the original default resolver for DNS operations, and * implements its own cache policies on top of that, and then set * itself as the default resolver for all later code to use. * * Since: 2.22 */ void g_resolver_set_default (GResolver *resolver) { if (default_resolver) g_object_unref (default_resolver); default_resolver = g_object_ref (resolver); } /* Bionic has res_init() but it's not in any header */ #ifdef __BIONIC__ int res_init (void); #endif static void g_resolver_maybe_reload (GResolver *resolver) { #ifdef G_OS_UNIX struct stat st; if (stat (_PATH_RESCONF, &st) == 0) { if (st.st_mtime != resolver->priv->resolv_conf_timestamp) { resolver->priv->resolv_conf_timestamp = st.st_mtime; #ifdef HAVE_RES_INIT res_init (); #endif g_signal_emit (resolver, signals[RELOAD], 0); } } #endif } /* filter out duplicates, cf. https://bugzilla.gnome.org/show_bug.cgi?id=631379 */ static void remove_duplicates (GList *addrs) { GList *l; GList *ll; GList *lll; /* TODO: if this is too slow (it's O(n^2) but n is typically really * small), we can do something more clever but note that we must not * change the order of elements... */ for (l = addrs; l != NULL; l = l->next) { GInetAddress *address = G_INET_ADDRESS (l->data); for (ll = l->next; ll != NULL; ll = lll) { GInetAddress *other_address = G_INET_ADDRESS (ll->data); lll = ll->next; if (g_inet_address_equal (address, other_address)) { g_object_unref (other_address); /* we never return the first element */ g_warn_if_fail (g_list_delete_link (addrs, ll) == addrs); } } } } /** * g_resolver_lookup_by_name: * @resolver: a #GResolver * @hostname: the hostname to look up * @cancellable: (allow-none): a #GCancellable, or %NULL * @error: return location for a #GError, or %NULL * * Synchronously resolves @hostname to determine its associated IP * address(es). @hostname may be an ASCII-only or UTF-8 hostname, or * the textual form of an IP address (in which case this just becomes * a wrapper around g_inet_address_new_from_string()). * * On success, g_resolver_lookup_by_name() will return a #GList of * #GInetAddress, sorted in order of preference and guaranteed to not * contain duplicates. That is, if using the result to connect to * @hostname, you should attempt to connect to the first address * first, then the second if the first fails, etc. If you are using * the result to listen on a socket, it is appropriate to add each * result using e.g. g_socket_listener_add_address(). * * If the DNS resolution fails, @error (if non-%NULL) will be set to a * value from #GResolverError. * * If @cancellable is non-%NULL, it can be used to cancel the * operation, in which case @error (if non-%NULL) will be set to * %G_IO_ERROR_CANCELLED. * * If you are planning to connect to a socket on the resolved IP * address, it may be easier to create a #GNetworkAddress and use its * #GSocketConnectable interface. * * Return value: (element-type GInetAddress) (transfer full): a #GList * of #GInetAddress, or %NULL on error. You * must unref each of the addresses and free the list when you are * done with it. (You can use g_resolver_free_addresses() to do this.) * * Since: 2.22 */ GList * g_resolver_lookup_by_name (GResolver *resolver, const gchar *hostname, GCancellable *cancellable, GError **error) { GInetAddress *addr; GList *addrs; gchar *ascii_hostname = NULL; g_return_val_if_fail (G_IS_RESOLVER (resolver), NULL); g_return_val_if_fail (hostname != NULL, NULL); /* Check if @hostname is just an IP address */ addr = g_inet_address_new_from_string (hostname); if (addr) return g_list_append (NULL, addr); if (g_hostname_is_non_ascii (hostname)) hostname = ascii_hostname = g_hostname_to_ascii (hostname); g_resolver_maybe_reload (resolver); addrs = G_RESOLVER_GET_CLASS (resolver)-> lookup_by_name (resolver, hostname, cancellable, error); remove_duplicates (addrs); g_free (ascii_hostname); return addrs; } /** * g_resolver_lookup_by_name_async: * @resolver: a #GResolver * @hostname: the hostname to look up the address of * @cancellable: (allow-none): a #GCancellable, or %NULL * @callback: (scope async): callback to call after resolution completes * @user_data: (closure): data for @callback * * Begins asynchronously resolving @hostname to determine its * associated IP address(es), and eventually calls @callback, which * must call g_resolver_lookup_by_name_finish() to get the result. * See g_resolver_lookup_by_name() for more details. * * Since: 2.22 */ void g_resolver_lookup_by_name_async (GResolver *resolver, const gchar *hostname, GCancellable *cancellable, GAsyncReadyCallback callback, gpointer user_data) { GInetAddress *addr; gchar *ascii_hostname = NULL; g_return_if_fail (G_IS_RESOLVER (resolver)); g_return_if_fail (hostname != NULL); /* Check if @hostname is just an IP address */ addr = g_inet_address_new_from_string (hostname); if (addr) { GTask *task; task = g_task_new (resolver, cancellable, callback, user_data); g_task_set_source_tag (task, g_resolver_lookup_by_name_async); g_task_return_pointer (task, g_list_append (NULL, addr), (GDestroyNotify) g_resolver_free_addresses); g_object_unref (task); return; } if (g_hostname_is_non_ascii (hostname)) hostname = ascii_hostname = g_hostname_to_ascii (hostname); g_resolver_maybe_reload (resolver); G_RESOLVER_GET_CLASS (resolver)-> lookup_by_name_async (resolver, hostname, cancellable, callback, user_data); g_free (ascii_hostname); } /** * g_resolver_lookup_by_name_finish: * @resolver: a #GResolver * @result: the result passed to your #GAsyncReadyCallback * @error: return location for a #GError, or %NULL * * Retrieves the result of a call to * g_resolver_lookup_by_name_async(). * * If the DNS resolution failed, @error (if non-%NULL) will be set to * a value from #GResolverError. If the operation was cancelled, * @error will be set to %G_IO_ERROR_CANCELLED. * * Return value: (element-type GInetAddress) (transfer full): a #GList * of #GInetAddress, or %NULL on error. See g_resolver_lookup_by_name() * for more details. * * Since: 2.22 */ GList * g_resolver_lookup_by_name_finish (GResolver *resolver, GAsyncResult *result, GError **error) { GList *addrs; g_return_val_if_fail (G_IS_RESOLVER (resolver), NULL); if (g_async_result_legacy_propagate_error (result, error)) return NULL; else if (g_async_result_is_tagged (result, g_resolver_lookup_by_name_async)) { /* Handle the stringified-IP-addr case */ return g_task_propagate_pointer (G_TASK (result), error); } addrs = G_RESOLVER_GET_CLASS (resolver)-> lookup_by_name_finish (resolver, result, error); remove_duplicates (addrs); return addrs; } /** * g_resolver_free_addresses: (skip) * @addresses: a #GList of #GInetAddress * * Frees @addresses (which should be the return value from * g_resolver_lookup_by_name() or g_resolver_lookup_by_name_finish()). * (This is a convenience method; you can also simply free the results * by hand.) * * Since: 2.22 */ void g_resolver_free_addresses (GList *addresses) { GList *a; for (a = addresses; a; a = a->next) g_object_unref (a->data); g_list_free (addresses); } /** * g_resolver_lookup_by_address: * @resolver: a #GResolver * @address: the address to reverse-resolve * @cancellable: (allow-none): a #GCancellable, or %NULL * @error: return location for a #GError, or %NULL * * Synchronously reverse-resolves @address to determine its * associated hostname. * * If the DNS resolution fails, @error (if non-%NULL) will be set to * a value from #GResolverError. * * If @cancellable is non-%NULL, it can be used to cancel the * operation, in which case @error (if non-%NULL) will be set to * %G_IO_ERROR_CANCELLED. * * Return value: a hostname (either ASCII-only, or in ASCII-encoded * form), or %NULL on error. * * Since: 2.22 */ gchar * g_resolver_lookup_by_address (GResolver *resolver, GInetAddress *address, GCancellable *cancellable, GError **error) { g_return_val_if_fail (G_IS_RESOLVER (resolver), NULL); g_return_val_if_fail (G_IS_INET_ADDRESS (address), NULL); g_resolver_maybe_reload (resolver); return G_RESOLVER_GET_CLASS (resolver)-> lookup_by_address (resolver, address, cancellable, error); } /** * g_resolver_lookup_by_address_async: * @resolver: a #GResolver * @address: the address to reverse-resolve * @cancellable: (allow-none): a #GCancellable, or %NULL * @callback: (scope async): callback to call after resolution completes * @user_data: (closure): data for @callback * * Begins asynchronously reverse-resolving @address to determine its * associated hostname, and eventually calls @callback, which must * call g_resolver_lookup_by_address_finish() to get the final result. * * Since: 2.22 */ void g_resolver_lookup_by_address_async (GResolver *resolver, GInetAddress *address, GCancellable *cancellable, GAsyncReadyCallback callback, gpointer user_data) { g_return_if_fail (G_IS_RESOLVER (resolver)); g_return_if_fail (G_IS_INET_ADDRESS (address)); g_resolver_maybe_reload (resolver); G_RESOLVER_GET_CLASS (resolver)-> lookup_by_address_async (resolver, address, cancellable, callback, user_data); } /** * g_resolver_lookup_by_address_finish: * @resolver: a #GResolver * @result: the result passed to your #GAsyncReadyCallback * @error: return location for a #GError, or %NULL * * Retrieves the result of a previous call to * g_resolver_lookup_by_address_async(). * * If the DNS resolution failed, @error (if non-%NULL) will be set to * a value from #GResolverError. If the operation was cancelled, * @error will be set to %G_IO_ERROR_CANCELLED. * * Return value: a hostname (either ASCII-only, or in ASCII-encoded * form), or %NULL on error. * * Since: 2.22 */ gchar * g_resolver_lookup_by_address_finish (GResolver *resolver, GAsyncResult *result, GError **error) { g_return_val_if_fail (G_IS_RESOLVER (resolver), NULL); if (g_async_result_legacy_propagate_error (result, error)) return NULL; return G_RESOLVER_GET_CLASS (resolver)-> lookup_by_address_finish (resolver, result, error); } static gchar * g_resolver_get_service_rrname (const char *service, const char *protocol, const char *domain) { gchar *rrname, *ascii_domain = NULL; if (g_hostname_is_non_ascii (domain)) domain = ascii_domain = g_hostname_to_ascii (domain); rrname = g_strdup_printf ("_%s._%s.%s", service, protocol, domain); g_free (ascii_domain); return rrname; } /** * g_resolver_lookup_service: * @resolver: a #GResolver * @service: the service type to look up (eg, "ldap") * @protocol: the networking protocol to use for @service (eg, "tcp") * @domain: the DNS domain to look up the service in * @cancellable: (allow-none): a #GCancellable, or %NULL * @error: return location for a #GError, or %NULL * * Synchronously performs a DNS SRV lookup for the given @service and * @protocol in the given @domain and returns an array of #GSrvTarget. * @domain may be an ASCII-only or UTF-8 hostname. Note also that the * @service and @protocol arguments do not * include the leading underscore that appears in the actual DNS * entry. * * On success, g_resolver_lookup_service() will return a #GList of * #GSrvTarget, sorted in order of preference. (That is, you should * attempt to connect to the first target first, then the second if * the first fails, etc.) * * If the DNS resolution fails, @error (if non-%NULL) will be set to * a value from #GResolverError. * * If @cancellable is non-%NULL, it can be used to cancel the * operation, in which case @error (if non-%NULL) will be set to * %G_IO_ERROR_CANCELLED. * * If you are planning to connect to the service, it is usually easier * to create a #GNetworkService and use its #GSocketConnectable * interface. * * Return value: (element-type GSrvTarget) (transfer full): a #GList of #GSrvTarget, * or %NULL on error. You must free each of the targets and the list when you are * done with it. (You can use g_resolver_free_targets() to do this.) * * Since: 2.22 */ GList * g_resolver_lookup_service (GResolver *resolver, const gchar *service, const gchar *protocol, const gchar *domain, GCancellable *cancellable, GError **error) { GList *targets; gchar *rrname; g_return_val_if_fail (G_IS_RESOLVER (resolver), NULL); g_return_val_if_fail (service != NULL, NULL); g_return_val_if_fail (protocol != NULL, NULL); g_return_val_if_fail (domain != NULL, NULL); rrname = g_resolver_get_service_rrname (service, protocol, domain); g_resolver_maybe_reload (resolver); targets = G_RESOLVER_GET_CLASS (resolver)-> lookup_service (resolver, rrname, cancellable, error); g_free (rrname); return targets; } /** * g_resolver_lookup_service_async: * @resolver: a #GResolver * @service: the service type to look up (eg, "ldap") * @protocol: the networking protocol to use for @service (eg, "tcp") * @domain: the DNS domain to look up the service in * @cancellable: (allow-none): a #GCancellable, or %NULL * @callback: (scope async): callback to call after resolution completes * @user_data: (closure): data for @callback * * Begins asynchronously performing a DNS SRV lookup for the given * @service and @protocol in the given @domain, and eventually calls * @callback, which must call g_resolver_lookup_service_finish() to * get the final result. See g_resolver_lookup_service() for more * details. * * Since: 2.22 */ void g_resolver_lookup_service_async (GResolver *resolver, const gchar *service, const gchar *protocol, const gchar *domain, GCancellable *cancellable, GAsyncReadyCallback callback, gpointer user_data) { gchar *rrname; g_return_if_fail (G_IS_RESOLVER (resolver)); g_return_if_fail (service != NULL); g_return_if_fail (protocol != NULL); g_return_if_fail (domain != NULL); rrname = g_resolver_get_service_rrname (service, protocol, domain); g_resolver_maybe_reload (resolver); G_RESOLVER_GET_CLASS (resolver)-> lookup_service_async (resolver, rrname, cancellable, callback, user_data); g_free (rrname); } /** * g_resolver_lookup_service_finish: * @resolver: a #GResolver * @result: the result passed to your #GAsyncReadyCallback * @error: return location for a #GError, or %NULL * * Retrieves the result of a previous call to * g_resolver_lookup_service_async(). * * If the DNS resolution failed, @error (if non-%NULL) will be set to * a value from #GResolverError. If the operation was cancelled, * @error will be set to %G_IO_ERROR_CANCELLED. * * Return value: (element-type GSrvTarget) (transfer full): a #GList of #GSrvTarget, * or %NULL on error. See g_resolver_lookup_service() for more details. * * Since: 2.22 */ GList * g_resolver_lookup_service_finish (GResolver *resolver, GAsyncResult *result, GError **error) { g_return_val_if_fail (G_IS_RESOLVER (resolver), NULL); if (g_async_result_legacy_propagate_error (result, error)) return NULL; return G_RESOLVER_GET_CLASS (resolver)-> lookup_service_finish (resolver, result, error); } /** * g_resolver_free_targets: (skip) * @targets: a #GList of #GSrvTarget * * Frees @targets (which should be the return value from * g_resolver_lookup_service() or g_resolver_lookup_service_finish()). * (This is a convenience method; you can also simply free the * results by hand.) * * Since: 2.22 */ void g_resolver_free_targets (GList *targets) { GList *t; for (t = targets; t; t = t->next) g_srv_target_free (t->data); g_list_free (targets); } /** * g_resolver_lookup_records: * @resolver: a #GResolver * @rrname: the DNS name to lookup the record for * @record_type: the type of DNS record to lookup * @cancellable: (allow-none): a #GCancellable, or %NULL * @error: return location for a #GError, or %NULL * * Synchronously performs a DNS record lookup for the given @rrname and returns * a list of records as #GVariant tuples. See #GResolverRecordType for * information on what the records contain for each @record_type. * * If the DNS resolution fails, @error (if non-%NULL) will be set to * a value from #GResolverError. * * If @cancellable is non-%NULL, it can be used to cancel the * operation, in which case @error (if non-%NULL) will be set to * %G_IO_ERROR_CANCELLED. * * Return value: (element-type GVariant) (transfer full): a #GList of #GVariant, * or %NULL on error. You must free each of the records and the list when you are * done with it. (You can use g_list_free_full() with g_variant_unref() to do this.) * * Since: 2.34 */ GList * g_resolver_lookup_records (GResolver *resolver, const gchar *rrname, GResolverRecordType record_type, GCancellable *cancellable, GError **error) { GList *records; g_return_val_if_fail (G_IS_RESOLVER (resolver), NULL); g_return_val_if_fail (rrname != NULL, NULL); g_resolver_maybe_reload (resolver); records = G_RESOLVER_GET_CLASS (resolver)-> lookup_records (resolver, rrname, record_type, cancellable, error); return records; } /** * g_resolver_lookup_records_async: * @resolver: a #GResolver * @rrname: the DNS name to lookup the record for * @record_type: the type of DNS record to lookup * @cancellable: (allow-none): a #GCancellable, or %NULL * @callback: (scope async): callback to call after resolution completes * @user_data: (closure): data for @callback * * Begins asynchronously performing a DNS lookup for the given * @rrname, and eventually calls @callback, which must call * g_resolver_lookup_records_finish() to get the final result. See * g_resolver_lookup_records() for more details. * * Since: 2.34 */ void g_resolver_lookup_records_async (GResolver *resolver, const gchar *rrname, GResolverRecordType record_type, GCancellable *cancellable, GAsyncReadyCallback callback, gpointer user_data) { g_return_if_fail (G_IS_RESOLVER (resolver)); g_return_if_fail (rrname != NULL); g_resolver_maybe_reload (resolver); G_RESOLVER_GET_CLASS (resolver)-> lookup_records_async (resolver, rrname, record_type, cancellable, callback, user_data); } /** * g_resolver_lookup_records_finish: * @resolver: a #GResolver * @result: the result passed to your #GAsyncReadyCallback * @error: return location for a #GError, or %NULL * * Retrieves the result of a previous call to * g_resolver_lookup_records_async(). Returns a list of records as #GVariant * tuples. See #GResolverRecordType for information on what the records contain. * * If the DNS resolution failed, @error (if non-%NULL) will be set to * a value from #GResolverError. If the operation was cancelled, * @error will be set to %G_IO_ERROR_CANCELLED. * * Return value: (element-type GVariant) (transfer full): a #GList of #GVariant, * or %NULL on error. You must free each of the records and the list when you are * done with it. (You can use g_list_free_full() with g_variant_unref() to do this.) * * Since: 2.34 */ GList * g_resolver_lookup_records_finish (GResolver *resolver, GAsyncResult *result, GError **error) { g_return_val_if_fail (G_IS_RESOLVER (resolver), NULL); return G_RESOLVER_GET_CLASS (resolver)-> lookup_records_finish (resolver, result, error); } guint64 g_resolver_get_serial (GResolver *resolver) { g_return_val_if_fail (G_IS_RESOLVER (resolver), 0); g_resolver_maybe_reload (resolver); #ifdef G_OS_UNIX return (guint64) resolver->priv->resolv_conf_timestamp; #else return 1; #endif } /** * g_resolver_error_quark: * * Gets the #GResolver Error Quark. * * Return value: a #GQuark. * * Since: 2.22 */ G_DEFINE_QUARK (g-resolver-error-quark, g_resolver_error)