glib/gio/gthreadedresolver.c

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/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
/* GIO - GLib Input, Output and Streaming Library
2009-05-04 00:04:31 +02:00
*
* 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 <stdio.h>
#include <string.h>
#include "gthreadedresolver.h"
#include "gnetworkingprivate.h"
#include "gcancellable.h"
#include "gsimpleasyncresult.h"
#include "gsocketaddress.h"
G_DEFINE_TYPE (GThreadedResolver, g_threaded_resolver, G_TYPE_RESOLVER)
static void threaded_resolver_thread (gpointer thread_data, gpointer pool_data);
static void
g_threaded_resolver_init (GThreadedResolver *gtr)
{
gtr->thread_pool = g_thread_pool_new (threaded_resolver_thread, gtr,
-1, FALSE, NULL);
}
static void
finalize (GObject *object)
{
GThreadedResolver *gtr = G_THREADED_RESOLVER (object);
g_thread_pool_free (gtr->thread_pool, FALSE, FALSE);
G_OBJECT_CLASS (g_threaded_resolver_parent_class)->finalize (object);
}
/* A GThreadedResolverRequest represents a request in progress
* (usually, but see case 1). It is refcounted, to make sure that it
* doesn't get freed too soon. In particular, it can't be freed until
* (a) the resolver thread has finished resolving, (b) the calling
* thread has received an answer, and (c) no other thread could be in
* the process of trying to cancel it.
*
* The possibilities:
*
* 1. Synchronous non-cancellable request: in this case, the request
* is simply done in the calling thread, without using
* GThreadedResolverRequest at all.
*
* 2. Synchronous cancellable request: A req is created with a GCond,
* and 3 refs (for the resolution thread, the calling thread, and
* the cancellation signal handler).
*
* a. If the resolution completes successfully, the thread pool
* function (threaded_resolver_thread()) will call
* g_threaded_resolver_request_complete(), which will detach
* the "cancelled" signal handler (dropping one ref on req)
* and signal the GCond, and then unref the req. The calling
* thread receives the signal from the GCond, processes the
* response, and unrefs the req, causing it to be freed.
*
* b. If the resolution is cancelled before completing,
* request_cancelled() will call
* g_threaded_resolver_request_complete(), which will detach
* the signal handler (as above, unreffing the req), set
* req->error to indicate that it was cancelled, and signal
* the GCond. The calling thread receives the signal from the
* GCond, processes the response, and unrefs the req.
* Eventually, the resolver thread finishes resolving (or
* times out in the resolver) and calls
* g_threaded_resolver_request_complete() again, but
* _request_complete() does nothing this time since the
* request is already complete. The thread pool func then
* unrefs the req, causing it to be freed.
*
* 3. Asynchronous request: A req is created with a GSimpleAsyncResult
* (and no GCond). The calling thread's ref on req is set up to be
* automatically dropped when the async_result is freed. Two
* sub-possibilities:
*
* a. If the resolution completes, the thread pool function
* (threaded_resolver_thread()) will call
* g_threaded_resolver_request_complete(), which will detach
* the "cancelled" signal handler (if it was present)
* (unreffing the req), queue the async_result to complete in
* an idle handler, unref the async_result (which is still
* reffed by the idle handler though), and then unref the req.
* The main thread then invokes the async_result's callback
* and processes the response. When it finishes, the
* async_result drops the ref that was taken by
* g_simple_async_result_complete_in_idle(), which causes the
* async_result to be freed, which causes req to be unreffed
* and freed.
*
* b. If the resolution is cancelled, request_cancelled() will
* call g_threaded_resolver_request_complete(), which will
* detach the signal handler (as above, unreffing the req) set
* req->error to indicate that it was cancelled, and queue and
* unref the async_result. The main thread completes the
* async_request and unrefs it and the req, as above.
* Eventually, the resolver thread finishes resolving (or
* times out in the resolver) and calls
* g_threaded_resolver_request_complete() again, but
* _request_complete() does nothing this time since the
* request is already complete. The thread pool func then
* unrefs the req, causing it to be freed.
*
* g_threaded_resolver_request_complete() ensures that if the request
* completes and cancels "at the same time" that only one of the two
* conditions gets processed.
*/
typedef struct _GThreadedResolverRequest GThreadedResolverRequest;
typedef void (*GThreadedResolverResolveFunc) (GThreadedResolverRequest *, GError **);
typedef void (*GThreadedResolverFreeFunc) (GThreadedResolverRequest *);
struct _GThreadedResolverRequest {
GThreadedResolverResolveFunc resolve_func;
GThreadedResolverFreeFunc free_func;
union {
struct {
gchar *hostname;
GList *addresses;
} name;
struct {
GInetAddress *address;
gchar *name;
} address;
struct {
gchar *rrname;
GList *targets;
} service;
} u;
GCancellable *cancellable;
GError *error;
GMutex *mutex;
guint ref_count;
GCond *cond;
GSimpleAsyncResult *async_result;
gboolean complete;
};
static void g_threaded_resolver_request_unref (GThreadedResolverRequest *req);
static void request_cancelled (GCancellable *cancellable, gpointer req);
static void request_cancelled_disconnect_notify (gpointer req, GClosure *closure);
static GThreadedResolverRequest *
g_threaded_resolver_request_new (GThreadedResolverResolveFunc resolve_func,
GThreadedResolverFreeFunc free_func,
GCancellable *cancellable)
{
GThreadedResolverRequest *req;
req = g_slice_new0 (GThreadedResolverRequest);
req->resolve_func = resolve_func;
req->free_func = free_func;
/* Initial refcount is 2; one for the caller and one for resolve_func */
req->ref_count = 2;
req->mutex = g_mutex_new ();
/* Initially locked; caller must unlock */
g_mutex_lock (req->mutex);
if (cancellable)
{
req->ref_count++;
req->cancellable = g_object_ref (cancellable);
g_signal_connect_data (cancellable, "cancelled",
G_CALLBACK (request_cancelled), req,
request_cancelled_disconnect_notify, 0);
}
return req;
}
static void
g_threaded_resolver_request_unref (GThreadedResolverRequest *req)
{
guint ref_count;
g_mutex_lock (req->mutex);
ref_count = --req->ref_count;
g_mutex_unlock (req->mutex);
if (ref_count > 0)
return;
g_mutex_free (req->mutex);
if (req->cond)
g_cond_free (req->cond);
if (req->error)
g_error_free (req->error);
if (req->free_func)
req->free_func (req);
/* We don't have to free req->cancellable or req->async_result,
* since (if set), they must already have been freed by
* request_complete() in order to get here.
*/
g_slice_free (GThreadedResolverRequest, req);
}
static void
g_threaded_resolver_request_complete (GThreadedResolverRequest *req,
gboolean cancelled)
{
g_mutex_lock (req->mutex);
if (req->complete)
{
/* The req was cancelled, and now it has finished resolving as
* well. But we have nowhere to send the result, so just return.
*/
g_mutex_unlock (req->mutex);
return;
}
req->complete = TRUE;
g_mutex_unlock (req->mutex);
if (req->cancellable)
{
/* Possibly propagate a cancellation error */
if (cancelled && !req->error)
g_cancellable_set_error_if_cancelled (req->cancellable, &req->error);
/* Drop the signal handler's ref on @req */
g_signal_handlers_disconnect_by_func (req->cancellable, request_cancelled, req);
g_object_unref (req->cancellable);
req->cancellable = NULL;
}
if (req->cond)
g_cond_signal (req->cond);
else if (req->async_result)
{
if (req->error)
g_simple_async_result_set_from_error (req->async_result, req->error);
g_simple_async_result_complete_in_idle (req->async_result);
/* Drop our ref on the async_result, which will eventually cause
* it to drop its ref on req.
*/
g_object_unref (req->async_result);
req->async_result = NULL;
}
}
static void
request_cancelled (GCancellable *cancellable,
gpointer user_data)
{
GThreadedResolverRequest *req = user_data;
g_threaded_resolver_request_complete (req, TRUE);
/* We can't actually cancel the resolver thread; it will eventually
* complete on its own and call request_complete() again, which will
* do nothing the second time.
*/
}
static void
request_cancelled_disconnect_notify (gpointer req,
GClosure *closure)
{
g_threaded_resolver_request_unref (req);
}
static void
threaded_resolver_thread (gpointer thread_data,
gpointer pool_data)
{
GThreadedResolverRequest *req = thread_data;
req->resolve_func (req, &req->error);
g_threaded_resolver_request_complete (req, FALSE);
g_threaded_resolver_request_unref (req);
2009-05-04 00:04:31 +02:00
}
static void
resolve_sync (GThreadedResolver *gtr,
GThreadedResolverRequest *req,
GError **error)
{
if (!req->cancellable || !gtr->thread_pool)
{
req->resolve_func (req, error);
g_mutex_unlock (req->mutex);
g_threaded_resolver_request_complete (req, FALSE);
g_threaded_resolver_request_unref (req);
return;
}
req->cond = g_cond_new ();
g_thread_pool_push (gtr->thread_pool, req, &req->error);
if (!req->error)
g_cond_wait (req->cond, req->mutex);
g_mutex_unlock (req->mutex);
if (req->error)
{
g_propagate_error (error, req->error);
req->error = NULL;
}
}
static void
resolve_async (GThreadedResolver *gtr,
GThreadedResolverRequest *req,
GAsyncReadyCallback callback,
gpointer user_data,
gpointer tag)
{
req->async_result = g_simple_async_result_new (G_OBJECT (gtr),
callback, user_data, tag);
g_simple_async_result_set_op_res_gpointer (req->async_result, req,
(GDestroyNotify)g_threaded_resolver_request_unref);
g_thread_pool_push (gtr->thread_pool, req, NULL);
g_mutex_unlock (req->mutex);
}
static GThreadedResolverRequest *
resolve_finish (GResolver *resolver,
GAsyncResult *result,
gpointer tag,
GError **error)
{
g_return_val_if_fail (g_simple_async_result_is_valid (result, G_OBJECT (resolver), tag), NULL);
return g_simple_async_result_get_op_res_gpointer (G_SIMPLE_ASYNC_RESULT (result));
}
static void
do_lookup_by_name (GThreadedResolverRequest *req,
GError **error)
{
struct addrinfo *res = NULL;
gint retval;
retval = getaddrinfo (req->u.name.hostname, NULL,
&_g_resolver_addrinfo_hints, &res);
req->u.name.addresses =
_g_resolver_addresses_from_addrinfo (req->u.name.hostname, res, retval, error);
if (res)
freeaddrinfo (res);
}
static GList *
lookup_by_name (GResolver *resolver,
const gchar *hostname,
GCancellable *cancellable,
GError **error)
{
GThreadedResolver *gtr = G_THREADED_RESOLVER (resolver);
GThreadedResolverRequest *req;
GList *addresses;
req = g_threaded_resolver_request_new (do_lookup_by_name, NULL, cancellable);
req->u.name.hostname = (gchar *)hostname;
resolve_sync (gtr, req, error);
addresses = req->u.name.addresses;
g_threaded_resolver_request_unref (req);
return addresses;
}
static void
free_lookup_by_name (GThreadedResolverRequest *req)
{
g_free (req->u.name.hostname);
if (req->u.name.addresses)
g_resolver_free_addresses (req->u.name.addresses);
}
static void
lookup_by_name_async (GResolver *resolver,
const gchar *hostname,
GCancellable *cancellable,
GAsyncReadyCallback callback,
gpointer user_data)
{
GThreadedResolver *gtr = G_THREADED_RESOLVER (resolver);
GThreadedResolverRequest *req;
req = g_threaded_resolver_request_new (do_lookup_by_name, free_lookup_by_name,
cancellable);
req->u.name.hostname = g_strdup (hostname);
resolve_async (gtr, req, callback, user_data, lookup_by_name_async);
}
static GList *
lookup_by_name_finish (GResolver *resolver,
GAsyncResult *result,
GError **error)
{
GThreadedResolverRequest *req;
GList *addresses;
req = resolve_finish (resolver, result, lookup_by_name_async, error);
addresses = req->u.name.addresses;
req->u.name.addresses = NULL;
return addresses;
}
static void
do_lookup_by_address (GThreadedResolverRequest *req,
GError **error)
{
struct sockaddr_storage sockaddr;
gsize sockaddr_size;
gchar name[NI_MAXHOST];
gint retval;
_g_resolver_address_to_sockaddr (req->u.address.address,
&sockaddr, &sockaddr_size);
retval = getnameinfo ((struct sockaddr *)&sockaddr, sockaddr_size,
name, sizeof (name), NULL, 0, NI_NAMEREQD);
req->u.address.name = _g_resolver_name_from_nameinfo (req->u.address.address,
name, retval, error);
}
static gchar *
lookup_by_address (GResolver *resolver,
GInetAddress *address,
GCancellable *cancellable,
GError **error)
{
GThreadedResolver *gtr = G_THREADED_RESOLVER (resolver);
GThreadedResolverRequest *req;
gchar *name;
req = g_threaded_resolver_request_new (do_lookup_by_address, NULL, cancellable);
req->u.address.address = address;
resolve_sync (gtr, req, error);
name = req->u.address.name;
g_threaded_resolver_request_unref (req);
return name;
}
static void
free_lookup_by_address (GThreadedResolverRequest *req)
{
g_object_unref (req->u.address.address);
if (req->u.address.name)
g_free (req->u.address.name);
}
static void
lookup_by_address_async (GResolver *resolver,
GInetAddress *address,
GCancellable *cancellable,
GAsyncReadyCallback callback,
gpointer user_data)
{
GThreadedResolver *gtr = G_THREADED_RESOLVER (resolver);
GThreadedResolverRequest *req;
req = g_threaded_resolver_request_new (do_lookup_by_address,
free_lookup_by_address,
cancellable);
req->u.address.address = g_object_ref (address);
resolve_async (gtr, req, callback, user_data, lookup_by_address_async);
}
static gchar *
lookup_by_address_finish (GResolver *resolver,
GAsyncResult *result,
GError **error)
{
GThreadedResolverRequest *req;
gchar *name;
req = resolve_finish (resolver, result, lookup_by_address_async, error);
name = req->u.address.name;
req->u.address.name = NULL;
return name;
}
static void
do_lookup_service (GThreadedResolverRequest *req,
GError **error)
{
#if defined(G_OS_UNIX)
gint len, herr;
guchar answer[1024];
#elif defined(G_OS_WIN32)
DNS_STATUS status;
DNS_RECORD *results;
#endif
#if defined(G_OS_UNIX)
len = res_query (req->u.service.rrname, C_IN, T_SRV, answer, sizeof (answer));
herr = h_errno;
req->u.service.targets = _g_resolver_targets_from_res_query (req->u.service.rrname, answer, len, herr, error);
#elif defined(G_OS_WIN32)
status = DnsQuery_A (req->u.service.rrname, DNS_TYPE_SRV,
DNS_QUERY_STANDARD, NULL, &results, NULL);
req->u.service.targets = _g_resolver_targets_from_DnsQuery (req->u.service.rrname, status, results, error);
DnsRecordListFree (results, DnsFreeRecordList);
#endif
}
static GList *
lookup_service (GResolver *resolver,
const gchar *rrname,
GCancellable *cancellable,
GError **error)
{
GThreadedResolver *gtr = G_THREADED_RESOLVER (resolver);
GThreadedResolverRequest *req;
GList *targets;
req = g_threaded_resolver_request_new (do_lookup_service, NULL, cancellable);
req->u.service.rrname = (char *)rrname;
resolve_sync (gtr, req, error);
targets = req->u.service.targets;
g_threaded_resolver_request_unref (req);
return targets;
}
static void
free_lookup_service (GThreadedResolverRequest *req)
{
g_free (req->u.service.rrname);
if (req->u.service.targets)
g_resolver_free_targets (req->u.service.targets);
}
static void
lookup_service_async (GResolver *resolver,
const char *rrname,
GCancellable *cancellable,
GAsyncReadyCallback callback,
gpointer user_data)
{
GThreadedResolver *gtr = G_THREADED_RESOLVER (resolver);
GThreadedResolverRequest *req;
req = g_threaded_resolver_request_new (do_lookup_service,
free_lookup_service,
cancellable);
req->u.service.rrname = g_strdup (rrname);
resolve_async (gtr, req, callback, user_data, lookup_service_async);
}
static GList *
lookup_service_finish (GResolver *resolver,
GAsyncResult *result,
GError **error)
{
GThreadedResolverRequest *req;
GList *targets;
req = resolve_finish (resolver, result, lookup_service_async, error);
targets = req->u.service.targets;
req->u.service.targets = NULL;
return targets;
}
static void
g_threaded_resolver_class_init (GThreadedResolverClass *threaded_class)
{
GResolverClass *resolver_class = G_RESOLVER_CLASS (threaded_class);
GObjectClass *object_class = G_OBJECT_CLASS (threaded_class);
resolver_class->lookup_by_name = lookup_by_name;
resolver_class->lookup_by_name_async = lookup_by_name_async;
resolver_class->lookup_by_name_finish = lookup_by_name_finish;
resolver_class->lookup_by_address = lookup_by_address;
resolver_class->lookup_by_address_async = lookup_by_address_async;
resolver_class->lookup_by_address_finish = lookup_by_address_finish;
resolver_class->lookup_service = lookup_service;
resolver_class->lookup_service_async = lookup_service_async;
resolver_class->lookup_service_finish = lookup_service_finish;
object_class->finalize = finalize;
}