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glib/gio/gresolver.c

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/* -*- 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 <glib.h>
#include "glibintl.h"
#include "gresolver.h"
#include "gnetworkingprivate.h"
#include "gasyncresult.h"
#include "ginetaddress.h"
#include "ginetsocketaddress.h"
#include "gsimpleasyncresult.h"
#include "gsrvtarget.h"
#include "gthreadedresolver.h"
#ifdef G_OS_UNIX
#include <sys/stat.h>
#endif
#include <stdlib.h>
/**
* 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 (GResolver, g_resolver, G_TYPE_OBJECT)
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));
/* Make sure _g_networking_init() has been called */
g_type_ensure (G_TYPE_INET_ADDRESS);
/* Initialize _g_resolver_addrinfo_hints */
#ifdef AI_ADDRCONFIG
_g_resolver_addrinfo_hints.ai_flags |= AI_ADDRCONFIG;
#endif
/* These two don't actually matter, they just get copied into the
* returned addrinfo structures (and then we ignore them). But if
* we leave them unset, we'll get back duplicate answers.
*/
_g_resolver_addrinfo_hints.ai_socktype = SOCK_STREAM;
_g_resolver_addrinfo_hints.ai_protocol = IPPROTO_TCP;
/**
* 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);
}
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;
res_init ();
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)
{
GSimpleAsyncResult *simple;
simple = g_simple_async_result_new (G_OBJECT (resolver),
callback, user_data,
g_resolver_lookup_by_name_async);
g_simple_async_result_set_op_res_gpointer (simple, addr, g_object_unref);
g_simple_async_result_complete_in_idle (simple);
g_object_unref (simple);
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_IS_SIMPLE_ASYNC_RESULT (result))
{
GSimpleAsyncResult *simple = G_SIMPLE_ASYNC_RESULT (result);
if (g_simple_async_result_propagate_error (simple, error))
return NULL;
/* Handle the stringified-IP-addr case */
if (g_simple_async_result_get_source_tag (simple) == g_resolver_lookup_by_name_async)
{
GInetAddress *addr;
addr = g_simple_async_result_get_op_res_gpointer (simple);
return g_list_append (NULL, g_object_ref (addr));
}
}
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_IS_SIMPLE_ASYNC_RESULT (result))
{
GSimpleAsyncResult *simple = G_SIMPLE_ASYNC_RESULT (result);
if (g_simple_async_result_propagate_error (simple, 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 <emphasis>do not</emphasis>
* 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_IS_SIMPLE_ASYNC_RESULT (result))
{
GSimpleAsyncResult *simple = G_SIMPLE_ASYNC_RESULT (result);
if (g_simple_async_result_propagate_error (simple, 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);
}
/**
* g_resolver_error_quark:
*
* Gets the #GResolver Error Quark.
*
* Return value: a #GQuark.
*
* Since: 2.22
*/
GQuark
g_resolver_error_quark (void)
{
return g_quark_from_static_string ("g-resolver-error-quark");
}
static GResolverError
g_resolver_error_from_addrinfo_error (gint err)
{
switch (err)
{
case EAI_FAIL:
#if defined(EAI_NODATA) && (EAI_NODATA != EAI_NONAME)
case EAI_NODATA:
#endif
case EAI_NONAME:
return G_RESOLVER_ERROR_NOT_FOUND;
case EAI_AGAIN:
return G_RESOLVER_ERROR_TEMPORARY_FAILURE;
default:
return G_RESOLVER_ERROR_INTERNAL;
}
}
struct addrinfo _g_resolver_addrinfo_hints;
/* Private method to process a getaddrinfo() response. */
GList *
_g_resolver_addresses_from_addrinfo (const char *hostname,
struct addrinfo *res,
gint gai_retval,
GError **error)
{
struct addrinfo *ai;
GSocketAddress *sockaddr;
GInetAddress *addr;
GList *addrs;
if (gai_retval != 0)
{
g_set_error (error, G_RESOLVER_ERROR,
g_resolver_error_from_addrinfo_error (gai_retval),
_("Error resolving '%s': %s"),
hostname, gai_strerror (gai_retval));
return NULL;
}
g_return_val_if_fail (res != NULL, NULL);
addrs = NULL;
for (ai = res; ai; ai = ai->ai_next)
{
sockaddr = g_socket_address_new_from_native (ai->ai_addr, ai->ai_addrlen);
if (!sockaddr || !G_IS_INET_SOCKET_ADDRESS (sockaddr))
continue;
addr = g_object_ref (g_inet_socket_address_get_address ((GInetSocketAddress *)sockaddr));
addrs = g_list_prepend (addrs, addr);
g_object_unref (sockaddr);
}
return g_list_reverse (addrs);
}
/* Private method to set up a getnameinfo() request */
void
_g_resolver_address_to_sockaddr (GInetAddress *address,
struct sockaddr_storage *sa,
gsize *len)
{
GSocketAddress *sockaddr;
sockaddr = g_inet_socket_address_new (address, 0);
g_socket_address_to_native (sockaddr, (struct sockaddr *)sa, sizeof (*sa), NULL);
*len = g_socket_address_get_native_size (sockaddr);
g_object_unref (sockaddr);
}
/* Private method to process a getnameinfo() response. */
char *
_g_resolver_name_from_nameinfo (GInetAddress *address,
const gchar *name,
gint gni_retval,
GError **error)
{
if (gni_retval != 0)
{
gchar *phys;
phys = g_inet_address_to_string (address);
g_set_error (error, G_RESOLVER_ERROR,
g_resolver_error_from_addrinfo_error (gni_retval),
_("Error reverse-resolving '%s': %s"),
phys ? phys : "(unknown)", gai_strerror (gni_retval));
g_free (phys);
return NULL;
}
return g_strdup (name);
}
#if defined(G_OS_UNIX)
static GVariant *
parse_res_srv (guchar *answer,
guchar *end,
guchar **p)
{
gchar namebuf[1024];
guint16 priority, weight, port;
GETSHORT (priority, *p);
GETSHORT (weight, *p);
GETSHORT (port, *p);
*p += dn_expand (answer, end, *p, namebuf, sizeof (namebuf));
return g_variant_new ("(qqqs)",
priority,
weight,
port,
namebuf);
}
static GVariant *
parse_res_soa (guchar *answer,
guchar *end,
guchar **p)
{
gchar mnamebuf[1024];
gchar rnamebuf[1024];
guint32 serial, refresh, retry, expire, ttl;
*p += dn_expand (answer, end, *p, mnamebuf, sizeof (mnamebuf));
*p += dn_expand (answer, end, *p, rnamebuf, sizeof (rnamebuf));
GETLONG (serial, *p);
GETLONG (refresh, *p);
GETLONG (retry, *p);
GETLONG (expire, *p);
GETLONG (ttl, *p);
return g_variant_new ("(ssuuuuu)",
mnamebuf,
rnamebuf,
serial,
refresh,
retry,
expire,
ttl);
}
static GVariant *
parse_res_ns (guchar *answer,
guchar *end,
guchar **p)
{
gchar namebuf[1024];
*p += dn_expand (answer, end, *p, namebuf, sizeof (namebuf));
return g_variant_new ("(s)", namebuf);
}
static GVariant *
parse_res_mx (guchar *answer,
guchar *end,
guchar **p)
{
gchar namebuf[1024];
guint16 preference;
GETSHORT (preference, *p);
*p += dn_expand (answer, end, *p, namebuf, sizeof (namebuf));
return g_variant_new ("(qs)",
preference,
namebuf);
}
static GVariant *
parse_res_txt (guchar *answer,
guchar *end,
guchar **p)
{
GVariant *record;
GPtrArray *array;
guchar *at = *p;
gsize len;
array = g_ptr_array_new_with_free_func (g_free);
while (at < end)
{
len = *(at++);
if (len > at - end)
break;
g_ptr_array_add (array, g_strndup ((gchar *)at, len));
at += len;
}
*p = at;
record = g_variant_new ("(@as)",
g_variant_new_strv ((const gchar **)array->pdata, array->len));
g_ptr_array_free (array, TRUE);
return record;
}
gint
_g_resolver_record_type_to_rrtype (GResolverRecordType type)
{
switch (type)
{
case G_RESOLVER_RECORD_SRV:
return T_SRV;
case G_RESOLVER_RECORD_TXT:
return T_TXT;
case G_RESOLVER_RECORD_SOA:
return T_SOA;
case G_RESOLVER_RECORD_NS:
return T_NS;
case G_RESOLVER_RECORD_MX:
return T_MX;
}
g_return_val_if_reached (-1);
}
/* Private method to process a res_query response into GSrvTargets */
GList *
_g_resolver_records_from_res_query (const gchar *rrname,
gint rrtype,
guchar *answer,
gint len,
gint herr,
GError **error)
{
gint count;
gchar namebuf[1024];
guchar *end, *p;
guint16 type, qclass, rdlength;
guint32 ttl;
HEADER *header;
GList *records;
GVariant *record;
if (len <= 0)
{
GResolverError errnum;
const gchar *format;
if (len == 0 || herr == HOST_NOT_FOUND || herr == NO_DATA)
{
errnum = G_RESOLVER_ERROR_NOT_FOUND;
format = _("No DNS record of the requested type for '%s'");
}
else if (herr == TRY_AGAIN)
{
errnum = G_RESOLVER_ERROR_TEMPORARY_FAILURE;
format = _("Temporarily unable to resolve '%s'");
}
else
{
errnum = G_RESOLVER_ERROR_INTERNAL;
format = _("Error resolving '%s'");
}
g_set_error (error, G_RESOLVER_ERROR, errnum, format, rrname);
return NULL;
}
records = NULL;
header = (HEADER *)answer;
p = answer + sizeof (HEADER);
end = answer + len;
/* Skip query */
count = ntohs (header->qdcount);
while (count-- && p < end)
{
p += dn_expand (answer, end, p, namebuf, sizeof (namebuf));
p += 4;
/* To silence gcc warnings */
namebuf[0] = namebuf[1];
}
/* Read answers */
count = ntohs (header->ancount);
while (count-- && p < end)
{
p += dn_expand (answer, end, p, namebuf, sizeof (namebuf));
GETSHORT (type, p);
GETSHORT (qclass, p);
GETLONG (ttl, p);
ttl = ttl; /* To avoid -Wunused-but-set-variable */
GETSHORT (rdlength, p);
if (type != rrtype || qclass != C_IN)
{
p += rdlength;
continue;
}
switch (rrtype)
{
case T_SRV:
record = parse_res_srv (answer, end, &p);
break;
case T_MX:
record = parse_res_mx (answer, end, &p);
break;
case T_SOA:
record = parse_res_soa (answer, end, &p);
break;
case T_NS:
record = parse_res_ns (answer, end, &p);
break;
case T_TXT:
record = parse_res_txt (answer, p + rdlength, &p);
break;
default:
g_warn_if_reached ();
record = NULL;
break;
}
if (record != NULL)
records = g_list_prepend (records, record);
}
return records;
}
#elif defined(G_OS_WIN32)
static GVariant *
parse_dns_srv (DNS_RECORD *rec)
{
return g_variant_new ("(qqqs)",
(guint16)rec->Data.SRV.wPriority,
(guint16)rec->Data.SRV.wWeight,
(guint16)rec->Data.SRV.wPort,
rec->Data.SRV.pNameTarget);
}
static GVariant *
parse_dns_soa (DNS_RECORD *rec)
{
return g_variant_new ("(ssuuuuu)",
rec->Data.SOA.pNamePrimaryServer,
rec->Data.SOA.pNameAdministrator,
(guint32)rec->Data.SOA.dwSerialNo,
(guint32)rec->Data.SOA.dwRefresh,
(guint32)rec->Data.SOA.dwRetry,
(guint32)rec->Data.SOA.dwExpire,
(guint32)rec->Data.SOA.dwDefaultTtl);
}
static GVariant *
parse_dns_ns (DNS_RECORD *rec)
{
return g_variant_new ("(s)", rec->Data.NS.pNameHost);
}
static GVariant *
parse_dns_mx (DNS_RECORD *rec)
{
return g_variant_new ("(qs)",
(guint16)rec->Data.MX.wPreference,
rec->Data.MX.pNameExchange);
}
static GVariant *
parse_dns_txt (DNS_RECORD *rec)
{
GVariant *record;
GPtrArray *array;
DWORD i;
array = g_ptr_array_new ();
for (i = 0; i < rec->Data.TXT.dwStringCount; i++)
g_ptr_array_add (array, rec->Data.TXT.pStringArray[i]);
record = g_variant_new ("(@as)",
g_variant_new_strv ((const gchar **)array->pdata, array->len));
g_ptr_array_free (array, TRUE);
return record;
}
WORD
_g_resolver_record_type_to_dnstype (GResolverRecordType type)
{
switch (type)
{
case G_RESOLVER_RECORD_SRV:
return DNS_TYPE_SRV;
case G_RESOLVER_RECORD_TXT:
return DNS_TYPE_TEXT;
case G_RESOLVER_RECORD_SOA:
return DNS_TYPE_SOA;
case G_RESOLVER_RECORD_NS:
return DNS_TYPE_NS;
case G_RESOLVER_RECORD_MX:
return DNS_TYPE_MX;
}
g_return_val_if_reached (-1);
}
/* Private method to process a DnsQuery response into GVariants */
GList *
_g_resolver_records_from_DnsQuery (const gchar *rrname,
WORD dnstype,
DNS_STATUS status,
DNS_RECORD *results,
GError **error)
{
DNS_RECORD *rec;
gpointer record;
GList *records;
if (status != ERROR_SUCCESS)
{
GResolverError errnum;
const gchar *format;
if (status == DNS_ERROR_RCODE_NAME_ERROR)
{
errnum = G_RESOLVER_ERROR_NOT_FOUND;
format = _("No DNS record of the requested type for '%s'");
}
else if (status == DNS_ERROR_RCODE_SERVER_FAILURE)
{
errnum = G_RESOLVER_ERROR_TEMPORARY_FAILURE;
format = _("Temporarily unable to resolve '%s'");
}
else
{
errnum = G_RESOLVER_ERROR_INTERNAL;
format = _("Error resolving '%s'");
}
g_set_error (error, G_RESOLVER_ERROR, errnum, format, rrname);
return NULL;
}
records = NULL;
for (rec = results; rec; rec = rec->pNext)
{
if (rec->wType != dnstype)
continue;
switch (dnstype)
{
case DNS_TYPE_SRV:
record = parse_dns_srv (rec);
break;
case DNS_TYPE_SOA:
record = parse_dns_soa (rec);
break;
case DNS_TYPE_NS:
record = parse_dns_ns (rec);
break;
case DNS_TYPE_MX:
record = parse_dns_mx (rec);
break;
case DNS_TYPE_TEXT:
record = parse_dns_txt (rec);
break;
default:
g_warn_if_reached ();
record = NULL;
break;
}
if (record != NULL)
records = g_list_prepend (records, g_variant_ref_sink (record));
}
return records;
}
#endif
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