gio/gunionvolumemonitor.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) 2006-2007 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, see <http://www.gnu.org/licenses/>.
  19  *
  20  * Author: Alexander Larsson <alexl@redhat.com>
  21  *         David Zeuthen <davidz@redhat.com>
  22  */
  23
  24 #include "config.h"
  25
  26 #include <string.h>
  27
  28 #include <glib.h>
  29 #include "gunionvolumemonitor.h"
  30 #include "gmountprivate.h"
  31 #include "giomodule-priv.h"
  32 #ifdef G_OS_UNIX
  33 #include "gunixvolumemonitor.h"
  34 #endif
  35 #include "gnativevolumemonitor.h"
  36
  37 #include "glibintl.h"
  38
  39
  40 struct _GUnionVolumeMonitor {
  41   GVolumeMonitor parent;
  42
  43   GList *monitors;
  44 };
  45
  46 static void g_union_volume_monitor_remove_monitor (GUnionVolumeMonitor *union_monitor,
  47                                                    GVolumeMonitor *child_monitor);
  48
  49
  50 #define g_union_volume_monitor_get_type _g_union_volume_monitor_get_type
  51 G_DEFINE_TYPE (GUnionVolumeMonitor, g_union_volume_monitor, G_TYPE_VOLUME_MONITOR);
  52
  53 static GRecMutex the_volume_monitor_mutex;
  54
  55 static GUnionVolumeMonitor *the_volume_monitor = NULL;
  56
  57 static void
  58 g_union_volume_monitor_finalize (GObject *object)
  59 {
  60   GUnionVolumeMonitor *monitor;
  61   GVolumeMonitor *child_monitor;
  62
  63   monitor = G_UNION_VOLUME_MONITOR (object);
  64
  65   while (monitor->monitors != NULL)
  66     {
  67       child_monitor = monitor->monitors->data;
  68       g_union_volume_monitor_remove_monitor (monitor,
  69                                              child_monitor);
  70       g_object_unref (child_monitor);
  71     }
  72
  73   G_OBJECT_CLASS (g_union_volume_monitor_parent_class)->finalize (object);
  74 }
  75
  76 static void
  77 g_union_volume_monitor_dispose (GObject *object)
  78 {
  79   GUnionVolumeMonitor *monitor;
  80   GVolumeMonitor *child_monitor;
  81   GList *l;
  82
  83   monitor = G_UNION_VOLUME_MONITOR (object);
  84
  85   g_rec_mutex_lock (&the_volume_monitor_mutex);
  86   the_volume_monitor = NULL;
  87
  88   for (l = monitor->monitors; l != NULL; l = l->next)
  89     {
  90       child_monitor = l->data;
  91       g_object_run_dispose (G_OBJECT (child_monitor));
  92     }
  93
  94   g_rec_mutex_unlock (&the_volume_monitor_mutex);
  95
  96   G_OBJECT_CLASS (g_union_volume_monitor_parent_class)->dispose (object);
  97 }
  98
  99 static GList *
 100 get_mounts (GVolumeMonitor *volume_monitor)
 101 {
 102   GUnionVolumeMonitor *monitor;
 103   GVolumeMonitor *child_monitor;
 104   GList *res;
 105   GList *l;
 106
 107   monitor = G_UNION_VOLUME_MONITOR (volume_monitor);
 108
 109   res = NULL;
 110
 111   g_rec_mutex_lock (&the_volume_monitor_mutex);
 112
 113   for (l = monitor->monitors; l != NULL; l = l->next)
 114     {
 115       child_monitor = l->data;
 116
 117       res = g_list_concat (res, g_volume_monitor_get_mounts (child_monitor));
 118     }
 119
 120   g_rec_mutex_unlock (&the_volume_monitor_mutex);
 121
 122   return res;
 123 }
 124
 125 static GList *
 126 get_volumes (GVolumeMonitor *volume_monitor)
 127 {
 128   GUnionVolumeMonitor *monitor;
 129   GVolumeMonitor *child_monitor;
 130   GList *res;
 131   GList *l;
 132
 133   monitor = G_UNION_VOLUME_MONITOR (volume_monitor);
 134
 135   res = NULL;
 136
 137   g_rec_mutex_lock (&the_volume_monitor_mutex);
 138
 139   for (l = monitor->monitors; l != NULL; l = l->next)
 140     {
 141       child_monitor = l->data;
 142
 143       res = g_list_concat (res, g_volume_monitor_get_volumes (child_monitor));
 144     }
 145
 146   g_rec_mutex_unlock (&the_volume_monitor_mutex);
 147
 148   return res;
 149 }
 150
 151 static GList *
 152 get_connected_drives (GVolumeMonitor *volume_monitor)
 153 {
 154   GUnionVolumeMonitor *monitor;
 155   GVolumeMonitor *child_monitor;
 156   GList *res;
 157   GList *l;
 158
 159   monitor = G_UNION_VOLUME_MONITOR (volume_monitor);
 160
 161   res = NULL;
 162
 163   g_rec_mutex_lock (&the_volume_monitor_mutex);
 164
 165   for (l = monitor->monitors; l != NULL; l = l->next)
 166     {
 167       child_monitor = l->data;
 168
 169       res = g_list_concat (res, g_volume_monitor_get_connected_drives (child_monitor));
 170     }
 171
 172   g_rec_mutex_unlock (&the_volume_monitor_mutex);
 173
 174   return res;
 175 }
 176
 177 static GVolume *
 178 get_volume_for_uuid (GVolumeMonitor *volume_monitor, const char *uuid)
 179 {
 180   GUnionVolumeMonitor *monitor;
 181   GVolumeMonitor *child_monitor;
 182   GVolume *volume;
 183   GList *l;
 184
 185   monitor = G_UNION_VOLUME_MONITOR (volume_monitor);
 186
 187   volume = NULL;
 188
 189   g_rec_mutex_lock (&the_volume_monitor_mutex);
 190
 191   for (l = monitor->monitors; l != NULL; l = l->next)
 192     {
 193       child_monitor = l->data;
 194
 195       volume = g_volume_monitor_get_volume_for_uuid (child_monitor, uuid);
 196       if (volume != NULL)
 197         break;
 198
 199     }
 200
 201   g_rec_mutex_unlock (&the_volume_monitor_mutex);
 202
 203   return volume;
 204 }
 205
 206 static GMount *
 207 get_mount_for_uuid (GVolumeMonitor *volume_monitor, const char *uuid)
 208 {
 209   GUnionVolumeMonitor *monitor;
 210   GVolumeMonitor *child_monitor;
 211   GMount *mount;
 212   GList *l;
 213
 214   monitor = G_UNION_VOLUME_MONITOR (volume_monitor);
 215
 216   mount = NULL;
 217
 218   g_rec_mutex_lock (&the_volume_monitor_mutex);
 219
 220   for (l = monitor->monitors; l != NULL; l = l->next)
 221     {
 222       child_monitor = l->data;
 223
 224       mount = g_volume_monitor_get_mount_for_uuid (child_monitor, uuid);
 225       if (mount != NULL)
 226         break;
 227
 228     }
 229
 230   g_rec_mutex_unlock (&the_volume_monitor_mutex);
 231
 232   return mount;
 233 }
 234
 235 static void
 236 g_union_volume_monitor_class_init (GUnionVolumeMonitorClass *klass)
 237 {
 238   GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
 239   GVolumeMonitorClass *monitor_class = G_VOLUME_MONITOR_CLASS (klass);
 240
 241   gobject_class->finalize = g_union_volume_monitor_finalize;
 242   gobject_class->dispose = g_union_volume_monitor_dispose;
 243
 244   monitor_class->get_connected_drives = get_connected_drives;
 245   monitor_class->get_volumes = get_volumes;
 246   monitor_class->get_mounts = get_mounts;
 247   monitor_class->get_volume_for_uuid = get_volume_for_uuid;
 248   monitor_class->get_mount_for_uuid = get_mount_for_uuid;
 249 }
 250
 251 static void
 252 child_volume_added (GVolumeMonitor      *child_monitor,
 253                     GVolume    *child_volume,
 254                     GUnionVolumeMonitor *union_monitor)
 255 {
 256   g_signal_emit_by_name (union_monitor,
 257                          "volume-added",
 258                          child_volume);
 259 }
 260
 261 static void
 262 child_volume_removed (GVolumeMonitor      *child_monitor,
 263                       GVolume    *child_volume,
 264                       GUnionVolumeMonitor *union_monitor)
 265 {
 266   g_signal_emit_by_name (union_monitor,
 267                          "volume-removed",
 268                          child_volume);
 269 }
 270
 271 static void
 272 child_volume_changed (GVolumeMonitor      *child_monitor,
 273                       GVolume    *child_volume,
 274                       GUnionVolumeMonitor *union_monitor)
 275 {
 276   g_signal_emit_by_name (union_monitor,
 277                          "volume-changed",
 278                          child_volume);
 279 }
 280
 281 static void
 282 child_mount_added (GVolumeMonitor      *child_monitor,
 283                    GMount              *child_mount,
 284                    GUnionVolumeMonitor *union_monitor)
 285 {
 286   g_signal_emit_by_name (union_monitor,
 287                          "mount-added",
 288                          child_mount);
 289 }
 290
 291 static void
 292 child_mount_removed (GVolumeMonitor      *child_monitor,
 293                      GMount              *child_mount,
 294                      GUnionVolumeMonitor *union_monitor)
 295 {
 296   g_signal_emit_by_name (union_monitor,
 297                          "mount-removed",
 298                          child_mount);
 299 }
 300
 301 static void
 302 child_mount_pre_unmount (GVolumeMonitor       *child_monitor,
 303                           GMount              *child_mount,
 304                           GUnionVolumeMonitor *union_monitor)
 305 {
 306   g_signal_emit_by_name (union_monitor,
 307                          "mount-pre-unmount",
 308                          child_mount);
 309 }
 310
 311
 312 static void
 313 child_mount_changed (GVolumeMonitor       *child_monitor,
 314                       GMount              *child_mount,
 315                       GUnionVolumeMonitor *union_monitor)
 316 {
 317   g_signal_emit_by_name (union_monitor,
 318                          "mount-changed",
 319                          child_mount);
 320 }
 321
 322 static void
 323 child_drive_connected (GVolumeMonitor      *child_monitor,
 324                        GDrive              *child_drive,
 325                        GUnionVolumeMonitor *union_monitor)
 326 {
 327   g_signal_emit_by_name (union_monitor,
 328                          "drive-connected",
 329                          child_drive);
 330 }
 331
 332 static void
 333 child_drive_disconnected (GVolumeMonitor      *child_monitor,
 334                           GDrive              *child_drive,
 335                           GUnionVolumeMonitor *union_monitor)
 336 {
 337   g_signal_emit_by_name (union_monitor,
 338                          "drive-disconnected",
 339                          child_drive);
 340 }
 341
 342 static void
 343 child_drive_changed (GVolumeMonitor      *child_monitor,
 344                      GDrive             *child_drive,
 345                      GUnionVolumeMonitor *union_monitor)
 346 {
 347   g_signal_emit_by_name (union_monitor,
 348                          "drive-changed",
 349                          child_drive);
 350 }
 351
 352 static void
 353 child_drive_eject_button (GVolumeMonitor      *child_monitor,
 354                           GDrive             *child_drive,
 355                           GUnionVolumeMonitor *union_monitor)
 356 {
 357   g_signal_emit_by_name (union_monitor,
 358                          "drive-eject-button",
 359                          child_drive);
 360 }
 361
 362 static void
 363 child_drive_stop_button (GVolumeMonitor      *child_monitor,
 364                          GDrive             *child_drive,
 365                          GUnionVolumeMonitor *union_monitor)
 366 {
 367   g_signal_emit_by_name (union_monitor,
 368                          "drive-stop-button",
 369                          child_drive);
 370 }
 371
 372 static void
 373 g_union_volume_monitor_add_monitor (GUnionVolumeMonitor *union_monitor,
 374                                     GVolumeMonitor      *volume_monitor)
 375 {
 376   if (g_list_find (union_monitor->monitors, volume_monitor))
 377     return;
 378
 379   union_monitor->monitors =
 380     g_list_prepend (union_monitor->monitors,
 381                     g_object_ref (volume_monitor));
 382
 383   g_signal_connect (volume_monitor, "volume-added", (GCallback)child_volume_added, union_monitor);
 384   g_signal_connect (volume_monitor, "volume-removed", (GCallback)child_volume_removed, union_monitor);
 385   g_signal_connect (volume_monitor, "volume-changed", (GCallback)child_volume_changed, union_monitor);
 386   g_signal_connect (volume_monitor, "mount-added", (GCallback)child_mount_added, union_monitor);
 387   g_signal_connect (volume_monitor, "mount-removed", (GCallback)child_mount_removed, union_monitor);
 388   g_signal_connect (volume_monitor, "mount-pre-unmount", (GCallback)child_mount_pre_unmount, union_monitor);
 389   g_signal_connect (volume_monitor, "mount-changed", (GCallback)child_mount_changed, union_monitor);
 390   g_signal_connect (volume_monitor, "drive-connected", (GCallback)child_drive_connected, union_monitor);
 391   g_signal_connect (volume_monitor, "drive-disconnected", (GCallback)child_drive_disconnected, union_monitor);
 392   g_signal_connect (volume_monitor, "drive-changed", (GCallback)child_drive_changed, union_monitor);
 393   g_signal_connect (volume_monitor, "drive-eject-button", (GCallback)child_drive_eject_button, union_monitor);
 394   g_signal_connect (volume_monitor, "drive-stop-button", (GCallback)child_drive_stop_button, union_monitor);
 395 }
 396
 397 static void
 398 g_union_volume_monitor_remove_monitor (GUnionVolumeMonitor *union_monitor,
 399                                        GVolumeMonitor      *child_monitor)
 400 {
 401   GList *l;
 402
 403   l = g_list_find (union_monitor->monitors, child_monitor);
 404   if (l == NULL)
 405     return;
 406
 407   union_monitor->monitors = g_list_delete_link (union_monitor->monitors, l);
 408
 409   g_signal_handlers_disconnect_by_func (child_monitor, child_volume_added, union_monitor);
 410   g_signal_handlers_disconnect_by_func (child_monitor, child_volume_removed, union_monitor);
 411   g_signal_handlers_disconnect_by_func (child_monitor, child_volume_changed, union_monitor);
 412   g_signal_handlers_disconnect_by_func (child_monitor, child_mount_added, union_monitor);
 413   g_signal_handlers_disconnect_by_func (child_monitor, child_mount_removed, union_monitor);
 414   g_signal_handlers_disconnect_by_func (child_monitor, child_mount_pre_unmount, union_monitor);
 415   g_signal_handlers_disconnect_by_func (child_monitor, child_mount_changed, union_monitor);
 416   g_signal_handlers_disconnect_by_func (child_monitor, child_drive_connected, union_monitor);
 417   g_signal_handlers_disconnect_by_func (child_monitor, child_drive_disconnected, union_monitor);
 418   g_signal_handlers_disconnect_by_func (child_monitor, child_drive_changed, union_monitor);
 419   g_signal_handlers_disconnect_by_func (child_monitor, child_drive_eject_button, union_monitor);
 420   g_signal_handlers_disconnect_by_func (child_monitor, child_drive_stop_button, union_monitor);
 421 }
 422
 423 static GType
 424 get_default_native_class (gpointer data)
 425 {
 426   GNativeVolumeMonitorClass *klass, *native_class, **native_class_out;
 427   const char *use_this;
 428   GIOExtensionPoint *ep;
 429   GIOExtension *extension;
 430   GList *l;
 431
 432   native_class_out = data;
 433
 434   use_this = g_getenv ("GIO_USE_VOLUME_MONITOR");
 435
 436   /* Ensure vfs in modules loaded */
 437   _g_io_modules_ensure_loaded ();
 438
 439   ep = g_io_extension_point_lookup (G_NATIVE_VOLUME_MONITOR_EXTENSION_POINT_NAME);
 440
 441   native_class = NULL;
 442   if (use_this)
 443     {
 444       extension = g_io_extension_point_get_extension_by_name (ep, use_this);
 445       if (extension)
 446         {
 447           klass = G_NATIVE_VOLUME_MONITOR_CLASS (g_io_extension_ref_class (extension));
 448           if (G_VOLUME_MONITOR_CLASS (klass)->is_supported())
 449             native_class = klass;
 450           else
 451             g_type_class_unref (klass);
 452         }
 453     }
 454
 455   if (native_class == NULL)
 456     {
 457       for (l = g_io_extension_point_get_extensions (ep); l != NULL; l = l->next)
 458         {
 459           extension = l->data;
 460           klass = G_NATIVE_VOLUME_MONITOR_CLASS (g_io_extension_ref_class (extension));
 461           if (G_VOLUME_MONITOR_CLASS (klass)->is_supported())
 462             {
 463               native_class = klass;
 464               break;
 465             }
 466           else
 467             g_type_class_unref (klass);
 468         }
 469     }
 470
 471   if (native_class)
 472     {
 473       *native_class_out = native_class;
 474       return G_TYPE_FROM_CLASS (native_class);
 475     }
 476   else
 477     return G_TYPE_INVALID;
 478 }
 479
 480 /* We return the class, with a ref taken.
 481  * This way we avoid unloading the class/module
 482  * between selecting the type and creating the
 483  * instance on the first call.
 484  */
 485 static GNativeVolumeMonitorClass *
 486 get_native_class (void)
 487 {
 488   static GOnce once_init = G_ONCE_INIT;
 489   GTypeClass *type_class;
 490
 491   type_class = NULL;
 492   g_once (&once_init, (GThreadFunc)get_default_native_class, &type_class);
 493
 494   if (type_class == NULL && once_init.retval != GUINT_TO_POINTER(G_TYPE_INVALID))
 495     type_class = g_type_class_ref ((GType)once_init.retval);
 496
 497   return (GNativeVolumeMonitorClass *)type_class;
 498 }
 499
 500 static void
 501 g_union_volume_monitor_init (GUnionVolumeMonitor *union_monitor)
 502 {
 503 }
 504
 505 static void
 506 populate_union_monitor (GUnionVolumeMonitor *union_monitor)
 507 {
 508   GVolumeMonitor *monitor;
 509   GNativeVolumeMonitorClass *native_class;
 510   GVolumeMonitorClass *klass;
 511   GIOExtensionPoint *ep;
 512   GIOExtension *extension;
 513   GList *l;
 514
 515   native_class = get_native_class ();
 516
 517   if (native_class != NULL)
 518     {
 519       monitor = g_object_new (G_TYPE_FROM_CLASS (native_class), NULL);
 520       g_union_volume_monitor_add_monitor (union_monitor, monitor);
 521       g_object_unref (monitor);
 522       g_type_class_unref (native_class);
 523     }
 524
 525   ep = g_io_extension_point_lookup (G_VOLUME_MONITOR_EXTENSION_POINT_NAME);
 526   for (l = g_io_extension_point_get_extensions (ep); l != NULL; l = l->next)
 527     {
 528       extension = l->data;
 529
 530       klass = G_VOLUME_MONITOR_CLASS (g_io_extension_ref_class (extension));
 531       if (klass->is_supported == NULL || klass->is_supported())
 532         {
 533           monitor = g_object_new (g_io_extension_get_type (extension), NULL);
 534           g_union_volume_monitor_add_monitor (union_monitor, monitor);
 535           g_object_unref (monitor);
 536         }
 537       g_type_class_unref (klass);
 538     }
 539 }
 540
 541 static GUnionVolumeMonitor *
 542 g_union_volume_monitor_new (void)
 543 {
 544   GUnionVolumeMonitor *monitor;
 545
 546   monitor = g_object_new (G_TYPE_UNION_VOLUME_MONITOR, NULL);
 547
 548   return monitor;
 549 }
 550
 551 /**
 552  * g_volume_monitor_get:
 553  *
 554  * Gets the volume monitor used by gio.
 555  *
 556  * Returns: (transfer full): a reference to the #GVolumeMonitor used by gio. Call
 557  *    g_object_unref() when done with it.
 558  **/
 559 GVolumeMonitor *
 560 g_volume_monitor_get (void)
 561 {
 562   GVolumeMonitor *vm;
 563
 564   g_rec_mutex_lock (&the_volume_monitor_mutex);
 565
 566   if (the_volume_monitor)
 567     vm = G_VOLUME_MONITOR (g_object_ref (the_volume_monitor));
 568   else
 569     {
 570       the_volume_monitor = g_union_volume_monitor_new ();
 571       populate_union_monitor (the_volume_monitor);
 572       vm = G_VOLUME_MONITOR (the_volume_monitor);
 573     }
 574
 575   g_rec_mutex_unlock (&the_volume_monitor_mutex);
 576
 577   return vm;
 578 }
 579
 580 GMount *
 581 _g_mount_get_for_mount_path (const gchar  *mount_path,
 582                              GCancellable *cancellable)
 583 {
 584   GNativeVolumeMonitorClass *klass;
 585   GMount *mount;
 586
 587   klass = get_native_class ();
 588   if (klass == NULL)
 589     return NULL;
 590
 591   mount = NULL;
 592
 593   if (klass->get_mount_for_mount_path)
 594     mount = klass->get_mount_for_mount_path (mount_path, cancellable);
 595
 596   /* TODO: How do we know this succeeded? Keep in mind that the native
 597    *       volume monitor may fail (e.g. not being able to connect to
 598    *       hald). Is the get_mount_for_mount_path() method allowed to
 599    *       return NULL? Seems like it is ... probably the method needs
 600    *       to take a boolean and write if it succeeds or not.. Messy.
 601    *       Very messy.
 602    */
 603
 604   g_type_class_unref (klass);
 605
 606   return mount;
 607 }
 608
 609 /**
 610  * g_volume_monitor_adopt_orphan_mount:
 611  * @mount: a #GMount object to find a parent for
 612  *
 613  * This function should be called by any #GVolumeMonitor
 614  * implementation when a new #GMount object is created that is not
 615  * associated with a #GVolume object. It must be called just before
 616  * emitting the @mount_added signal.
 617  *
 618  * If the return value is not %NULL, the caller must associate the
 619  * returned #GVolume object with the #GMount. This involves returning
 620  * it in its g_mount_get_volume() implementation. The caller must
 621  * also listen for the "removed" signal on the returned object
 622  * and give up its reference when handling that signal
 623  *
 624  * Similary, if implementing g_volume_monitor_adopt_orphan_mount(),
 625  * the implementor must take a reference to @mount and return it in
 626  * its g_volume_get_mount() implemented. Also, the implementor must
 627  * listen for the "unmounted" signal on @mount and give up its
 628  * reference upon handling that signal.
 629  *
 630  * There are two main use cases for this function.
 631  *
 632  * One is when implementing a user space file system driver that reads
 633  * blocks of a block device that is already represented by the native
 634  * volume monitor (for example a CD Audio file system driver). Such
 635  * a driver will generate its own #GMount object that needs to be
 636  * associated with the #GVolume object that represents the volume.
 637  *
 638  * The other is for implementing a #GVolumeMonitor whose sole purpose
 639  * is to return #GVolume objects representing entries in the users
 640  * "favorite servers" list or similar.
 641  *
 642  * Returns: (transfer full): the #GVolume object that is the parent for @mount or %NULL
 643  * if no wants to adopt the #GMount.
 644  *
 645  * Deprecated: 2.20: Instead of using this function, #GVolumeMonitor
 646  * implementations should instead create shadow mounts with the URI of
 647  * the mount they intend to adopt. See the proxy volume monitor in
 648  * gvfs for an example of this. Also see g_mount_is_shadowed(),
 649  * g_mount_shadow() and g_mount_unshadow() functions.
 650  */
 651 GVolume *
 652 g_volume_monitor_adopt_orphan_mount (GMount *mount)
 653 {
 654   GVolumeMonitor *child_monitor;
 655   GVolumeMonitorClass *child_monitor_class;
 656   GVolume *volume;
 657   GList *l;
 658
 659   g_return_val_if_fail (mount != NULL, NULL);
 660
 661   if (the_volume_monitor == NULL)
 662     return NULL;
 663
 664   volume = NULL;
 665
 666   g_rec_mutex_lock (&the_volume_monitor_mutex);
 667
 668   for (l = the_volume_monitor->monitors; l != NULL; l = l->next)
 669     {
 670       child_monitor = l->data;
 671       child_monitor_class = G_VOLUME_MONITOR_GET_CLASS (child_monitor);
 672
 673       if (child_monitor_class->adopt_orphan_mount != NULL)
 674         {
 675           volume = child_monitor_class->adopt_orphan_mount (mount, child_monitor);
 676           if (volume != NULL)
 677             break;
 678         }
 679     }
 680
 681   g_rec_mutex_unlock (&the_volume_monitor_mutex);
 682
 683   return volume;
 684 }