gio/gunixresolver.c

   1 /* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
   2
   3 /* GIO - GLib Input, Output and Streaming Library
   4  *
   5  * Copyright (C) 2008 Red Hat, Inc.
   6  *
   7  * This library is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2 of the License, or (at your option) any later version.
  11  *
  12  * This library is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General
  18  * Public License along with this library; if not, write to the
  19  * Free Software Foundation, Inc., 59 Temple Place, Suite 330,
  20  * Boston, MA 02111-1307, USA.
  21  */
  22
  23 #include "config.h"
  24 #include <glib.h>
  25 #include "glibintl.h"
  26
  27 #include <stdio.h>
  28 #include <string.h>
  29
  30 #include "gunixresolver.h"
  31 #include "gnetworkingprivate.h"
  32
  33 #include "gcancellable.h"
  34 #include "gsimpleasyncresult.h"
  35 #include "gsocketaddress.h"
  36
  37 #include "gioalias.h"
  38
  39 G_DEFINE_TYPE (GUnixResolver, g_unix_resolver, G_TYPE_THREADED_RESOLVER)
  40
  41 static gboolean g_unix_resolver_watch (GIOChannel   *iochannel,
  42                                        GIOCondition  condition,
  43                                        gpointer      user_data);
  44
  45 static void
  46 g_unix_resolver_init (GUnixResolver *gur)
  47 {
  48   gint fd;
  49   GIOChannel *io;
  50
  51   /* FIXME: how many workers? */
  52   gur->asyncns = _g_asyncns_new (2);
  53
  54   fd = _g_asyncns_fd (gur->asyncns);
  55   io = g_io_channel_unix_new (fd);
  56   gur->watch = g_io_add_watch (io, G_IO_IN | G_IO_HUP | G_IO_ERR,
  57                                g_unix_resolver_watch, gur);
  58   g_io_channel_unref (io);
  59 }
  60
  61 static void
  62 g_unix_resolver_finalize (GObject *object)
  63 {
  64   GUnixResolver *gur = G_UNIX_RESOLVER (object);
  65
  66   if (gur->watch)
  67     g_source_remove (gur->watch);
  68   _g_asyncns_free (gur->asyncns);
  69
  70   G_OBJECT_CLASS (g_unix_resolver_parent_class)->finalize (object);
  71 }
  72
  73 /* The various request possibilities:
  74  *
  75  * 1. Synchronous: handed off to the base class (GThreadedResolver);
  76  *    since it's never possible to cancel a synchronous request in a
  77  *    single-threaded program, the request is done in the calling
  78  *    thread.
  79  *
  80  * 2. Asynchronous: An appropriate _g_asyncns_query_t is created, and
  81  *    then a GUnixResolverRequest is created with that query and a
  82  *    GSimpleAsyncResult. Two sub-possibilities:
  83  *
  84  *      a. The resolution completes: g_unix_resolver_watch() sees that
  85  *         the request has completed, and calls
  86  *         g_unix_resolver_request_complete(), which detaches the
  87  *         "cancelled" signal handler (if it was present) and then
  88  *         immediately completes the async_result (since
  89  *         g_unix_resolver_watch() is already run from main-loop
  90  *         time.) After completing the async_result, it unrefs it,
  91  *         causing the req to be freed as well.
  92  *
  93  *      b. The resolution is cancelled: request_cancelled() calls
  94  *         _g_asyncns_cancel() to cancel the resolution. Then it calls
  95  *         g_unix_resolver_request_complete(), which detaches the
  96  *         signal handler, and queues async_result to complete in an
  97  *         idle handler. It then unrefs the async_result to ensure
  98  *         that after its callback runs, it will be destroyed, in turn
  99  *         causing the req to be freed. Because the asyncns resolution
 100  *         was cancelled, g_unix_resolver_watch() will never be
 101  *         triggered for this req.
 102  *
 103  *    Since there's only a single thread, it's not possible for the
 104  *    request to both complete and be cancelled "at the same time",
 105  *    and each of the two possibilities takes steps to block the other
 106  *    from being able to happen later, so it's always safe to free req
 107  *    after the async_result completes.
 108  */
 109
 110 typedef struct _GUnixResolverRequest GUnixResolverRequest;
 111 typedef void (*GUnixResolverFreeFunc) (GUnixResolverRequest *);
 112
 113 struct _GUnixResolverRequest {
 114   GUnixResolver *gur;
 115
 116   _g_asyncns_query_t *qy;
 117   union {
 118     gchar *hostname;
 119     GInetAddress *address;
 120     gchar *service;
 121   } u;
 122   GUnixResolverFreeFunc free_func;
 123
 124   GCancellable *cancellable;
 125   GSimpleAsyncResult *async_result;
 126
 127 };
 128
 129 static void g_unix_resolver_request_free (GUnixResolverRequest *req);
 130 static void request_cancelled (GCancellable *cancellable,
 131                                gpointer      user_data);
 132
 133 static GUnixResolverRequest *
 134 g_unix_resolver_request_new (GUnixResolver         *gur,
 135                              _g_asyncns_query_t    *qy,
 136                              GUnixResolverFreeFunc  free_func,
 137                              GCancellable          *cancellable,
 138                              GSimpleAsyncResult    *async_result)
 139 {
 140   GUnixResolverRequest *req;
 141
 142   req = g_slice_new0 (GUnixResolverRequest);
 143   req->gur = g_object_ref (gur);
 144   req->qy = qy;
 145   req->free_func = free_func;
 146
 147   if (cancellable)
 148     {
 149       req->cancellable = g_object_ref (cancellable);
 150       g_signal_connect (cancellable, "cancelled",
 151                         G_CALLBACK (request_cancelled), req);
 152     }
 153
 154   req->async_result = g_object_ref (async_result);
 155
 156   g_simple_async_result_set_op_res_gpointer (req->async_result, req, (GDestroyNotify)g_unix_resolver_request_free);
 157
 158   return req;
 159 }
 160
 161 static void
 162 g_unix_resolver_request_free (GUnixResolverRequest *req)
 163 {
 164   /* If the user didn't call _finish the qy will still be around. */
 165   if (req->qy)
 166     _g_asyncns_cancel (req->gur->asyncns, req->qy);
 167
 168   /* We don't have to free req->cancellable and req->async_result,
 169    * since they must already have been freed if we're here.
 170    */
 171
 172   g_slice_free (GUnixResolverRequest, req);
 173 }
 174
 175 static void
 176 g_unix_resolver_request_complete (GUnixResolverRequest *req,
 177                                   gboolean              need_idle)
 178 {
 179   if (req->cancellable)
 180     {
 181       g_signal_handlers_disconnect_by_func (req->cancellable, request_cancelled, req);
 182       g_object_unref (req->cancellable);
 183       req->cancellable = NULL;
 184     }
 185
 186   if (need_idle)
 187     g_simple_async_result_complete_in_idle (req->async_result);
 188   else
 189     g_simple_async_result_complete (req->async_result);
 190
 191   /* If we completed_in_idle, that will have taken an extra ref on
 192    * req->async_result; if not, then we're already done. Either way we
 193    * need to unref the async_result to make sure it eventually is
 194    * destroyed, causing req to be freed.
 195    */
 196   g_object_unref (req->async_result);
 197 }
 198
 199 static void
 200 request_cancelled (GCancellable *cancellable,
 201                    gpointer      user_data)
 202 {
 203   GUnixResolverRequest *req = user_data;
 204   GError *error = NULL;
 205
 206   _g_asyncns_cancel (req->gur->asyncns, req->qy);
 207   req->qy = NULL;
 208
 209   g_cancellable_set_error_if_cancelled (cancellable, &error);
 210   g_simple_async_result_set_from_error (req->async_result, error);
 211   g_error_free (error);
 212
 213   g_unix_resolver_request_complete (req, TRUE);
 214 }
 215
 216 static gboolean
 217 g_unix_resolver_watch (GIOChannel   *iochannel,
 218                        GIOCondition  condition,
 219                        gpointer      user_data)
 220 {
 221   GUnixResolver *gur = user_data;
 222   _g_asyncns_query_t *qy;
 223   GUnixResolverRequest *req;
 224
 225   if (condition & (G_IO_HUP | G_IO_ERR))
 226     {
 227       /* Shouldn't happen. Should we create a new asyncns? FIXME */
 228       g_warning ("asyncns died");
 229       gur->watch = 0;
 230       return FALSE;
 231     }
 232
 233   while (_g_asyncns_wait (gur->asyncns, FALSE) == 0 &&
 234          (qy = _g_asyncns_getnext (gur->asyncns)) != NULL)
 235     {
 236       req = _g_asyncns_getuserdata (gur->asyncns, qy);
 237       g_unix_resolver_request_complete (req, FALSE);
 238     }
 239
 240   return TRUE;
 241 }
 242
 243 static GUnixResolverRequest *
 244 resolve_async (GUnixResolver         *gur,
 245                _g_asyncns_query_t    *qy,
 246                GUnixResolverFreeFunc  free_func,
 247                GCancellable          *cancellable,
 248                GAsyncReadyCallback    callback,
 249                gpointer               user_data,
 250                gpointer               tag)
 251 {
 252   GSimpleAsyncResult *result;
 253   GUnixResolverRequest *req;
 254
 255   result = g_simple_async_result_new (G_OBJECT (gur), callback, user_data, tag);
 256   req = g_unix_resolver_request_new (gur, qy, free_func, cancellable, result);
 257   g_object_unref (result);
 258   _g_asyncns_setuserdata (gur->asyncns, qy, req);
 259
 260   return req;
 261 }
 262
 263 static void
 264 lookup_by_name_free (GUnixResolverRequest *req)
 265 {
 266   g_free (req->u.hostname);
 267 }
 268
 269 static void
 270 lookup_by_name_async (GResolver           *resolver,
 271                       const gchar         *hostname,
 272                       GCancellable        *cancellable,
 273                       GAsyncReadyCallback  callback,
 274                       gpointer             user_data)
 275 {
 276   GUnixResolver *gur = G_UNIX_RESOLVER (resolver);
 277   GUnixResolverRequest *req;
 278   _g_asyncns_query_t *qy;
 279
 280   qy = _g_asyncns_getaddrinfo (gur->asyncns, hostname, NULL,
 281                                &_g_resolver_addrinfo_hints);
 282   req = resolve_async (gur, qy, lookup_by_name_free, cancellable,
 283                        callback, user_data, lookup_by_name_async);
 284   req->u.hostname = g_strdup (hostname);
 285 }
 286
 287 static GList *
 288 lookup_by_name_finish (GResolver     *resolver,
 289                        GAsyncResult  *result,
 290                        GError       **error)
 291 {
 292   GSimpleAsyncResult *simple;
 293   GUnixResolverRequest *req;
 294   struct addrinfo *res;
 295   gint retval;
 296   GList *addresses;
 297
 298   g_return_val_if_fail (g_simple_async_result_is_valid (result, G_OBJECT (resolver), lookup_by_name_async), FALSE);
 299   simple = G_SIMPLE_ASYNC_RESULT (result);
 300
 301   req = g_simple_async_result_get_op_res_gpointer (simple);
 302   retval = _g_asyncns_getaddrinfo_done (req->gur->asyncns, req->qy, &res);
 303   req->qy = NULL;
 304   addresses = _g_resolver_addresses_from_addrinfo (req->u.hostname, res, retval, error);
 305   if (res)
 306     freeaddrinfo (res);
 307
 308   return addresses;
 309 }
 310
 311
 312 static void
 313 lookup_by_address_free (GUnixResolverRequest *req)
 314 {
 315   g_object_unref (req->u.address);
 316 }
 317
 318 static void
 319 lookup_by_address_async (GResolver           *resolver,
 320                          GInetAddress        *address,
 321                          GCancellable        *cancellable,
 322                          GAsyncReadyCallback  callback,
 323                          gpointer             user_data)
 324 {
 325   GUnixResolver *gur = G_UNIX_RESOLVER (resolver);
 326   GUnixResolverRequest *req;
 327   _g_asyncns_query_t *qy;
 328   struct sockaddr_storage sockaddr;
 329   gsize sockaddr_size;
 330
 331   _g_resolver_address_to_sockaddr (address, &sockaddr, &sockaddr_size);
 332   qy = _g_asyncns_getnameinfo (gur->asyncns,
 333                                (struct sockaddr *)&sockaddr, sockaddr_size,
 334                                NI_NAMEREQD, TRUE, FALSE);
 335   req = resolve_async (gur, qy, lookup_by_address_free, cancellable,
 336                        callback, user_data, lookup_by_address_async);
 337   req->u.address = g_object_ref (address);
 338 }
 339
 340 static gchar *
 341 lookup_by_address_finish (GResolver     *resolver,
 342                           GAsyncResult  *result,
 343                           GError       **error)
 344 {
 345   GSimpleAsyncResult *simple;
 346   GUnixResolverRequest *req;
 347   gchar host[NI_MAXHOST], *name;
 348   gint retval;
 349
 350   g_return_val_if_fail (g_simple_async_result_is_valid (result, G_OBJECT (resolver), lookup_by_address_async), FALSE);
 351   simple = G_SIMPLE_ASYNC_RESULT (result);
 352
 353   req = g_simple_async_result_get_op_res_gpointer (simple);
 354   retval = _g_asyncns_getnameinfo_done (req->gur->asyncns, req->qy,
 355                                         host, sizeof (host), NULL, 0);
 356   req->qy = NULL;
 357   name = _g_resolver_name_from_nameinfo (req->u.address, host, retval, error);
 358
 359   return name;
 360 }
 361
 362
 363 static void
 364 lookup_service_free (GUnixResolverRequest *req)
 365 {
 366   g_free (req->u.service);
 367 }
 368
 369 static void
 370 lookup_service_async (GResolver           *resolver,
 371                       const char          *rrname,
 372                       GCancellable        *cancellable,
 373                       GAsyncReadyCallback  callback,
 374                       gpointer             user_data)
 375 {
 376   GUnixResolver *gur = G_UNIX_RESOLVER (resolver);
 377   GUnixResolverRequest *req;
 378   _g_asyncns_query_t *qy;
 379
 380   qy = _g_asyncns_res_query (gur->asyncns, rrname, C_IN, T_SRV);
 381   req = resolve_async (gur, qy, lookup_service_free, cancellable,
 382                        callback, user_data, lookup_service_async);
 383   req->u.service = g_strdup (rrname);
 384 }
 385
 386 static GList *
 387 lookup_service_finish (GResolver     *resolver,
 388                        GAsyncResult  *result,
 389                        GError       **error)
 390 {
 391   GSimpleAsyncResult *simple;
 392   GUnixResolverRequest *req;
 393   guchar *answer;
 394   gint len, herr;
 395   GList *targets;
 396
 397   g_return_val_if_fail (g_simple_async_result_is_valid (result, G_OBJECT (resolver), lookup_service_async), FALSE);
 398   simple = G_SIMPLE_ASYNC_RESULT (result);
 399
 400   req = g_simple_async_result_get_op_res_gpointer (simple);
 401   len = _g_asyncns_res_done (req->gur->asyncns, req->qy, &answer);
 402   req->qy = NULL;
 403   if (len < 0)
 404     herr = h_errno;
 405   else
 406     herr = 0;
 407
 408   targets = _g_resolver_targets_from_res_query (req->u.service, answer, len, herr, error);
 409   _g_asyncns_freeanswer (answer);
 410
 411   return targets;
 412 }
 413
 414
 415 static void
 416 g_unix_resolver_class_init (GUnixResolverClass *unix_class)
 417 {
 418   GResolverClass *resolver_class = G_RESOLVER_CLASS (unix_class);
 419   GObjectClass *object_class = G_OBJECT_CLASS (unix_class);
 420
 421   resolver_class->lookup_by_name_async     = lookup_by_name_async;
 422   resolver_class->lookup_by_name_finish    = lookup_by_name_finish;
 423   resolver_class->lookup_by_address_async  = lookup_by_address_async;
 424   resolver_class->lookup_by_address_finish = lookup_by_address_finish;
 425   resolver_class->lookup_service_async     = lookup_service_async;
 426   resolver_class->lookup_service_finish    = lookup_service_finish;
 427
 428   object_class->finalize = g_unix_resolver_finalize;
 429 }
 430
 431 #define __G_UNIX_RESOLVER_C__
 432 #include "gioaliasdef.c"