qom/object.c

   1 /*
   2  * QEMU Object Model
   3  *
   4  * Copyright IBM, Corp. 2011
   5  *
   6  * Authors:
   7  *  Anthony Liguori   <[email protected]>
   8  *
   9  * This work is licensed under the terms of the GNU GPL, version 2 or later.
  10  * See the COPYING file in the top-level directory.
  11  */
  12
  13 #include "qom/object.h"
  14 #include "qemu-common.h"
  15 #include "qapi/visitor.h"
  16 #include "qapi/string-input-visitor.h"
  17 #include "qapi/string-output-visitor.h"
  18 #include "qapi/qmp/qerror.h"
  19
  20 /* TODO: replace QObject with a simpler visitor to avoid a dependency
  21  * of the QOM core on QObject?  */
  22 #include "qom/qom-qobject.h"
  23 #include "qapi/qmp/qobject.h"
  24 #include "qapi/qmp/qbool.h"
  25 #include "qapi/qmp/qint.h"
  26 #include "qapi/qmp/qstring.h"
  27
  28 #define MAX_INTERFACES 32
  29
  30 typedef struct InterfaceImpl InterfaceImpl;
  31 typedef struct TypeImpl TypeImpl;
  32
  33 struct InterfaceImpl
  34 {
  35     const char *typename;
  36 };
  37
  38 struct TypeImpl
  39 {
  40     const char *name;
  41
  42     size_t class_size;
  43
  44     size_t instance_size;
  45
  46     void (*class_init)(ObjectClass *klass, void *data);
  47     void (*class_base_init)(ObjectClass *klass, void *data);
  48     void (*class_finalize)(ObjectClass *klass, void *data);
  49
  50     void *class_data;
  51
  52     void (*instance_init)(Object *obj);
  53     void (*instance_finalize)(Object *obj);
  54
  55     bool abstract;
  56
  57     const char *parent;
  58     TypeImpl *parent_type;
  59
  60     ObjectClass *class;
  61
  62     int num_interfaces;
  63     InterfaceImpl interfaces[MAX_INTERFACES];
  64 };
  65
  66 static Type type_interface;
  67
  68 static GHashTable *type_table_get(void)
  69 {
  70     static GHashTable *type_table;
  71
  72     if (type_table == NULL) {
  73         type_table = g_hash_table_new(g_str_hash, g_str_equal);
  74     }
  75
  76     return type_table;
  77 }
  78
  79 static void type_table_add(TypeImpl *ti)
  80 {
  81     g_hash_table_insert(type_table_get(), (void *)ti->name, ti);
  82 }
  83
  84 static TypeImpl *type_table_lookup(const char *name)
  85 {
  86     return g_hash_table_lookup(type_table_get(), name);
  87 }
  88
  89 static TypeImpl *type_register_internal(const TypeInfo *info)
  90 {
  91     TypeImpl *ti = g_malloc0(sizeof(*ti));
  92     int i;
  93
  94     g_assert(info->name != NULL);
  95
  96     if (type_table_lookup(info->name) != NULL) {
  97         fprintf(stderr, "Registering `%s' which already exists\n", info->name);
  98         abort();
  99     }
 100
 101     ti->name = g_strdup(info->name);
 102     ti->parent = g_strdup(info->parent);
 103
 104     ti->class_size = info->class_size;
 105     ti->instance_size = info->instance_size;
 106
 107     ti->class_init = info->class_init;
 108     ti->class_base_init = info->class_base_init;
 109     ti->class_finalize = info->class_finalize;
 110     ti->class_data = info->class_data;
 111
 112     ti->instance_init = info->instance_init;
 113     ti->instance_finalize = info->instance_finalize;
 114
 115     ti->abstract = info->abstract;
 116
 117     for (i = 0; info->interfaces && info->interfaces[i].type; i++) {
 118         ti->interfaces[i].typename = g_strdup(info->interfaces[i].type);
 119     }
 120     ti->num_interfaces = i;
 121
 122     type_table_add(ti);
 123
 124     return ti;
 125 }
 126
 127 TypeImpl *type_register(const TypeInfo *info)
 128 {
 129     assert(info->parent);
 130     return type_register_internal(info);
 131 }
 132
 133 TypeImpl *type_register_static(const TypeInfo *info)
 134 {
 135     return type_register(info);
 136 }
 137
 138 static TypeImpl *type_get_by_name(const char *name)
 139 {
 140     if (name == NULL) {
 141         return NULL;
 142     }
 143
 144     return type_table_lookup(name);
 145 }
 146
 147 static TypeImpl *type_get_parent(TypeImpl *type)
 148 {
 149     if (!type->parent_type && type->parent) {
 150         type->parent_type = type_get_by_name(type->parent);
 151         g_assert(type->parent_type != NULL);
 152     }
 153
 154     return type->parent_type;
 155 }
 156
 157 static bool type_has_parent(TypeImpl *type)
 158 {
 159     return (type->parent != NULL);
 160 }
 161
 162 static size_t type_class_get_size(TypeImpl *ti)
 163 {
 164     if (ti->class_size) {
 165         return ti->class_size;
 166     }
 167
 168     if (type_has_parent(ti)) {
 169         return type_class_get_size(type_get_parent(ti));
 170     }
 171
 172     return sizeof(ObjectClass);
 173 }
 174
 175 static size_t type_object_get_size(TypeImpl *ti)
 176 {
 177     if (ti->instance_size) {
 178         return ti->instance_size;
 179     }
 180
 181     if (type_has_parent(ti)) {
 182         return type_object_get_size(type_get_parent(ti));
 183     }
 184
 185     return 0;
 186 }
 187
 188 static bool type_is_ancestor(TypeImpl *type, TypeImpl *target_type)
 189 {
 190     assert(target_type);
 191
 192     /* Check if typename is a direct ancestor of type */
 193     while (type) {
 194         if (type == target_type) {
 195             return true;
 196         }
 197
 198         type = type_get_parent(type);
 199     }
 200
 201     return false;
 202 }
 203
 204 static void type_initialize(TypeImpl *ti);
 205
 206 static void type_initialize_interface(TypeImpl *ti, const char *parent)
 207 {
 208     InterfaceClass *new_iface;
 209     TypeInfo info = { };
 210     TypeImpl *iface_impl;
 211
 212     info.parent = parent;
 213     info.name = g_strdup_printf("%s::%s", ti->name, info.parent);
 214     info.abstract = true;
 215
 216     iface_impl = type_register(&info);
 217     type_initialize(iface_impl);
 218     g_free((char *)info.name);
 219
 220     new_iface = (InterfaceClass *)iface_impl->class;
 221     new_iface->concrete_class = ti->class;
 222
 223     ti->class->interfaces = g_slist_append(ti->class->interfaces,
 224                                            iface_impl->class);
 225 }
 226
 227 static void type_initialize(TypeImpl *ti)
 228 {
 229     TypeImpl *parent;
 230
 231     if (ti->class) {
 232         return;
 233     }
 234
 235     ti->class_size = type_class_get_size(ti);
 236     ti->instance_size = type_object_get_size(ti);
 237
 238     ti->class = g_malloc0(ti->class_size);
 239
 240     parent = type_get_parent(ti);
 241     if (parent) {
 242         type_initialize(parent);
 243         GSList *e;
 244         int i;
 245
 246         g_assert(parent->class_size <= ti->class_size);
 247         memcpy(ti->class, parent->class, parent->class_size);
 248
 249         for (e = parent->class->interfaces; e; e = e->next) {
 250             ObjectClass *iface = e->data;
 251             type_initialize_interface(ti, object_class_get_name(iface));
 252         }
 253
 254         for (i = 0; i < ti->num_interfaces; i++) {
 255             TypeImpl *t = type_get_by_name(ti->interfaces[i].typename);
 256             for (e = ti->class->interfaces; e; e = e->next) {
 257                 TypeImpl *target_type = OBJECT_CLASS(e->data)->type;
 258
 259                 if (type_is_ancestor(target_type, t)) {
 260                     break;
 261                 }
 262             }
 263
 264             if (e) {
 265                 continue;
 266             }
 267
 268             type_initialize_interface(ti, ti->interfaces[i].typename);
 269         }
 270     }
 271
 272     ti->class->type = ti;
 273
 274     while (parent) {
 275         if (parent->class_base_init) {
 276             parent->class_base_init(ti->class, ti->class_data);
 277         }
 278         parent = type_get_parent(parent);
 279     }
 280
 281     if (ti->class_init) {
 282         ti->class_init(ti->class, ti->class_data);
 283     }
 284
 285
 286 }
 287
 288 static void object_init_with_type(Object *obj, TypeImpl *ti)
 289 {
 290     if (type_has_parent(ti)) {
 291         object_init_with_type(obj, type_get_parent(ti));
 292     }
 293
 294     if (ti->instance_init) {
 295         ti->instance_init(obj);
 296     }
 297 }
 298
 299 void object_initialize_with_type(void *data, TypeImpl *type)
 300 {
 301     Object *obj = data;
 302
 303     g_assert(type != NULL);
 304     type_initialize(type);
 305
 306     g_assert(type->instance_size >= sizeof(Object));
 307     g_assert(type->abstract == false);
 308
 309     memset(obj, 0, type->instance_size);
 310     obj->class = type->class;
 311     object_ref(obj);
 312     QTAILQ_INIT(&obj->properties);
 313     object_init_with_type(obj, type);
 314 }
 315
 316 void object_initialize(void *data, const char *typename)
 317 {
 318     TypeImpl *type = type_get_by_name(typename);
 319
 320     object_initialize_with_type(data, type);
 321 }
 322
 323 static inline bool object_property_is_child(ObjectProperty *prop)
 324 {
 325     return strstart(prop->type, "child<", NULL);
 326 }
 327
 328 static inline bool object_property_is_link(ObjectProperty *prop)
 329 {
 330     return strstart(prop->type, "link<", NULL);
 331 }
 332
 333 static void object_property_del_all(Object *obj)
 334 {
 335     while (!QTAILQ_EMPTY(&obj->properties)) {
 336         ObjectProperty *prop = QTAILQ_FIRST(&obj->properties);
 337
 338         QTAILQ_REMOVE(&obj->properties, prop, node);
 339
 340         if (prop->release) {
 341             prop->release(obj, prop->name, prop->opaque);
 342         }
 343
 344         g_free(prop->name);
 345         g_free(prop->type);
 346         g_free(prop);
 347     }
 348 }
 349
 350 static void object_property_del_child(Object *obj, Object *child, Error **errp)
 351 {
 352     ObjectProperty *prop;
 353
 354     QTAILQ_FOREACH(prop, &obj->properties, node) {
 355         if (object_property_is_child(prop) && prop->opaque == child) {
 356             object_property_del(obj, prop->name, errp);
 357             break;
 358         }
 359     }
 360 }
 361
 362 void object_unparent(Object *obj)
 363 {
 364     if (obj->parent) {
 365         object_property_del_child(obj->parent, obj, NULL);
 366     }
 367     if (obj->class->unparent) {
 368         (obj->class->unparent)(obj);
 369     }
 370 }
 371
 372 static void object_deinit(Object *obj, TypeImpl *type)
 373 {
 374     if (type->instance_finalize) {
 375         type->instance_finalize(obj);
 376     }
 377
 378     if (type_has_parent(type)) {
 379         object_deinit(obj, type_get_parent(type));
 380     }
 381 }
 382
 383 static void object_finalize(void *data)
 384 {
 385     Object *obj = data;
 386     TypeImpl *ti = obj->class->type;
 387
 388     object_deinit(obj, ti);
 389     object_property_del_all(obj);
 390
 391     g_assert(obj->ref == 0);
 392     if (obj->free) {
 393         obj->free(obj);
 394     }
 395 }
 396
 397 Object *object_new_with_type(Type type)
 398 {
 399     Object *obj;
 400
 401     g_assert(type != NULL);
 402     type_initialize(type);
 403
 404     obj = g_malloc(type->instance_size);
 405     object_initialize_with_type(obj, type);
 406     obj->free = g_free;
 407
 408     return obj;
 409 }
 410
 411 Object *object_new(const char *typename)
 412 {
 413     TypeImpl *ti = type_get_by_name(typename);
 414
 415     return object_new_with_type(ti);
 416 }
 417
 418 void object_delete(Object *obj)
 419 {
 420     object_unparent(obj);
 421     g_assert(obj->ref == 1);
 422     object_unref(obj);
 423 }
 424
 425 Object *object_dynamic_cast(Object *obj, const char *typename)
 426 {
 427     if (obj && object_class_dynamic_cast(object_get_class(obj), typename)) {
 428         return obj;
 429     }
 430
 431     return NULL;
 432 }
 433
 434 Object *object_dynamic_cast_assert(Object *obj, const char *typename)
 435 {
 436     Object *inst;
 437
 438     inst = object_dynamic_cast(obj, typename);
 439
 440     if (!inst && obj) {
 441         fprintf(stderr, "Object %p is not an instance of type %s\n",
 442                 obj, typename);
 443         abort();
 444     }
 445
 446     return inst;
 447 }
 448
 449 ObjectClass *object_class_dynamic_cast(ObjectClass *class,
 450                                        const char *typename)
 451 {
 452     TypeImpl *target_type = type_get_by_name(typename);
 453     TypeImpl *type = class->type;
 454     ObjectClass *ret = NULL;
 455
 456     if (type->num_interfaces && type_is_ancestor(target_type, type_interface)) {
 457         int found = 0;
 458         GSList *i;
 459
 460         for (i = class->interfaces; i; i = i->next) {
 461             ObjectClass *target_class = i->data;
 462
 463             if (type_is_ancestor(target_class->type, target_type)) {
 464                 ret = target_class;
 465                 found++;
 466             }
 467          }
 468
 469         /* The match was ambiguous, don't allow a cast */
 470         if (found > 1) {
 471             ret = NULL;
 472         }
 473     } else if (type_is_ancestor(type, target_type)) {
 474         ret = class;
 475     }
 476
 477     return ret;
 478 }
 479
 480 ObjectClass *object_class_dynamic_cast_assert(ObjectClass *class,
 481                                               const char *typename)
 482 {
 483     ObjectClass *ret = object_class_dynamic_cast(class, typename);
 484
 485     if (!ret) {
 486         fprintf(stderr, "Object %p is not an instance of type %s\n",
 487                 class, typename);
 488         abort();
 489     }
 490
 491     return ret;
 492 }
 493
 494 const char *object_get_typename(Object *obj)
 495 {
 496     return obj->class->type->name;
 497 }
 498
 499 ObjectClass *object_get_class(Object *obj)
 500 {
 501     return obj->class;
 502 }
 503
 504 const char *object_class_get_name(ObjectClass *klass)
 505 {
 506     return klass->type->name;
 507 }
 508
 509 ObjectClass *object_class_by_name(const char *typename)
 510 {
 511     TypeImpl *type = type_get_by_name(typename);
 512
 513     if (!type) {
 514         return NULL;
 515     }
 516
 517     type_initialize(type);
 518
 519     return type->class;
 520 }
 521
 522 ObjectClass *object_class_get_parent(ObjectClass *class)
 523 {
 524     TypeImpl *type = type_get_parent(class->type);
 525
 526     if (!type) {
 527         return NULL;
 528     }
 529
 530     type_initialize(type);
 531
 532     return type->class;
 533 }
 534
 535 typedef struct OCFData
 536 {
 537     void (*fn)(ObjectClass *klass, void *opaque);
 538     const char *implements_type;
 539     bool include_abstract;
 540     void *opaque;
 541 } OCFData;
 542
 543 static void object_class_foreach_tramp(gpointer key, gpointer value,
 544                                        gpointer opaque)
 545 {
 546     OCFData *data = opaque;
 547     TypeImpl *type = value;
 548     ObjectClass *k;
 549
 550     type_initialize(type);
 551     k = type->class;
 552
 553     if (!data->include_abstract && type->abstract) {
 554         return;
 555     }
 556
 557     if (data->implements_type &&
 558         !object_class_dynamic_cast(k, data->implements_type)) {
 559         return;
 560     }
 561
 562     data->fn(k, data->opaque);
 563 }
 564
 565 void object_class_foreach(void (*fn)(ObjectClass *klass, void *opaque),
 566                           const char *implements_type, bool include_abstract,
 567                           void *opaque)
 568 {
 569     OCFData data = { fn, implements_type, include_abstract, opaque };
 570
 571     g_hash_table_foreach(type_table_get(), object_class_foreach_tramp, &data);
 572 }
 573
 574 int object_child_foreach(Object *obj, int (*fn)(Object *child, void *opaque),
 575                          void *opaque)
 576 {
 577     ObjectProperty *prop;
 578     int ret = 0;
 579
 580     QTAILQ_FOREACH(prop, &obj->properties, node) {
 581         if (object_property_is_child(prop)) {
 582             ret = fn(prop->opaque, opaque);
 583             if (ret != 0) {
 584                 break;
 585             }
 586         }
 587     }
 588     return ret;
 589 }
 590
 591 static void object_class_get_list_tramp(ObjectClass *klass, void *opaque)
 592 {
 593     GSList **list = opaque;
 594
 595     *list = g_slist_prepend(*list, klass);
 596 }
 597
 598 GSList *object_class_get_list(const char *implements_type,
 599                               bool include_abstract)
 600 {
 601     GSList *list = NULL;
 602
 603     object_class_foreach(object_class_get_list_tramp,
 604                          implements_type, include_abstract, &list);
 605     return list;
 606 }
 607
 608 void object_ref(Object *obj)
 609 {
 610     obj->ref++;
 611 }
 612
 613 void object_unref(Object *obj)
 614 {
 615     g_assert(obj->ref > 0);
 616     obj->ref--;
 617
 618     /* parent always holds a reference to its children */
 619     if (obj->ref == 0) {
 620         object_finalize(obj);
 621     }
 622 }
 623
 624 void object_property_add(Object *obj, const char *name, const char *type,
 625                          ObjectPropertyAccessor *get,
 626                          ObjectPropertyAccessor *set,
 627                          ObjectPropertyRelease *release,
 628                          void *opaque, Error **errp)
 629 {
 630     ObjectProperty *prop = g_malloc0(sizeof(*prop));
 631
 632     prop->name = g_strdup(name);
 633     prop->type = g_strdup(type);
 634
 635     prop->get = get;
 636     prop->set = set;
 637     prop->release = release;
 638     prop->opaque = opaque;
 639
 640     QTAILQ_INSERT_TAIL(&obj->properties, prop, node);
 641 }
 642
 643 ObjectProperty *object_property_find(Object *obj, const char *name,
 644                                      Error **errp)
 645 {
 646     ObjectProperty *prop;
 647
 648     QTAILQ_FOREACH(prop, &obj->properties, node) {
 649         if (strcmp(prop->name, name) == 0) {
 650             return prop;
 651         }
 652     }
 653
 654     error_set(errp, QERR_PROPERTY_NOT_FOUND, "", name);
 655     return NULL;
 656 }
 657
 658 void object_property_del(Object *obj, const char *name, Error **errp)
 659 {
 660     ObjectProperty *prop = object_property_find(obj, name, errp);
 661     if (prop == NULL) {
 662         return;
 663     }
 664
 665     if (prop->release) {
 666         prop->release(obj, name, prop->opaque);
 667     }
 668
 669     QTAILQ_REMOVE(&obj->properties, prop, node);
 670
 671     g_free(prop->name);
 672     g_free(prop->type);
 673     g_free(prop);
 674 }
 675
 676 void object_property_get(Object *obj, Visitor *v, const char *name,
 677                          Error **errp)
 678 {
 679     ObjectProperty *prop = object_property_find(obj, name, errp);
 680     if (prop == NULL) {
 681         return;
 682     }
 683
 684     if (!prop->get) {
 685         error_set(errp, QERR_PERMISSION_DENIED);
 686     } else {
 687         prop->get(obj, v, prop->opaque, name, errp);
 688     }
 689 }
 690
 691 void object_property_set(Object *obj, Visitor *v, const char *name,
 692                          Error **errp)
 693 {
 694     ObjectProperty *prop = object_property_find(obj, name, errp);
 695     if (prop == NULL) {
 696         return;
 697     }
 698
 699     if (!prop->set) {
 700         error_set(errp, QERR_PERMISSION_DENIED);
 701     } else {
 702         prop->set(obj, v, prop->opaque, name, errp);
 703     }
 704 }
 705
 706 void object_property_set_str(Object *obj, const char *value,
 707                              const char *name, Error **errp)
 708 {
 709     QString *qstr = qstring_from_str(value);
 710     object_property_set_qobject(obj, QOBJECT(qstr), name, errp);
 711
 712     QDECREF(qstr);
 713 }
 714
 715 char *object_property_get_str(Object *obj, const char *name,
 716                               Error **errp)
 717 {
 718     QObject *ret = object_property_get_qobject(obj, name, errp);
 719     QString *qstring;
 720     char *retval;
 721
 722     if (!ret) {
 723         return NULL;
 724     }
 725     qstring = qobject_to_qstring(ret);
 726     if (!qstring) {
 727         error_set(errp, QERR_INVALID_PARAMETER_TYPE, name, "string");
 728         retval = NULL;
 729     } else {
 730         retval = g_strdup(qstring_get_str(qstring));
 731     }
 732
 733     QDECREF(qstring);
 734     return retval;
 735 }
 736
 737 void object_property_set_link(Object *obj, Object *value,
 738                               const char *name, Error **errp)
 739 {
 740     object_property_set_str(obj, object_get_canonical_path(value),
 741                             name, errp);
 742 }
 743
 744 Object *object_property_get_link(Object *obj, const char *name,
 745                                  Error **errp)
 746 {
 747     char *str = object_property_get_str(obj, name, errp);
 748     Object *target = NULL;
 749
 750     if (str && *str) {
 751         target = object_resolve_path(str, NULL);
 752         if (!target) {
 753             error_set(errp, QERR_DEVICE_NOT_FOUND, str);
 754         }
 755     }
 756
 757     g_free(str);
 758     return target;
 759 }
 760
 761 void object_property_set_bool(Object *obj, bool value,
 762                               const char *name, Error **errp)
 763 {
 764     QBool *qbool = qbool_from_int(value);
 765     object_property_set_qobject(obj, QOBJECT(qbool), name, errp);
 766
 767     QDECREF(qbool);
 768 }
 769
 770 bool object_property_get_bool(Object *obj, const char *name,
 771                               Error **errp)
 772 {
 773     QObject *ret = object_property_get_qobject(obj, name, errp);
 774     QBool *qbool;
 775     bool retval;
 776
 777     if (!ret) {
 778         return false;
 779     }
 780     qbool = qobject_to_qbool(ret);
 781     if (!qbool) {
 782         error_set(errp, QERR_INVALID_PARAMETER_TYPE, name, "boolean");
 783         retval = false;
 784     } else {
 785         retval = qbool_get_int(qbool);
 786     }
 787
 788     QDECREF(qbool);
 789     return retval;
 790 }
 791
 792 void object_property_set_int(Object *obj, int64_t value,
 793                              const char *name, Error **errp)
 794 {
 795     QInt *qint = qint_from_int(value);
 796     object_property_set_qobject(obj, QOBJECT(qint), name, errp);
 797
 798     QDECREF(qint);
 799 }
 800
 801 int64_t object_property_get_int(Object *obj, const char *name,
 802                                 Error **errp)
 803 {
 804     QObject *ret = object_property_get_qobject(obj, name, errp);
 805     QInt *qint;
 806     int64_t retval;
 807
 808     if (!ret) {
 809         return -1;
 810     }
 811     qint = qobject_to_qint(ret);
 812     if (!qint) {
 813         error_set(errp, QERR_INVALID_PARAMETER_TYPE, name, "int");
 814         retval = -1;
 815     } else {
 816         retval = qint_get_int(qint);
 817     }
 818
 819     QDECREF(qint);
 820     return retval;
 821 }
 822
 823 void object_property_parse(Object *obj, const char *string,
 824                            const char *name, Error **errp)
 825 {
 826     StringInputVisitor *mi;
 827     mi = string_input_visitor_new(string);
 828     object_property_set(obj, string_input_get_visitor(mi), name, errp);
 829
 830     string_input_visitor_cleanup(mi);
 831 }
 832
 833 char *object_property_print(Object *obj, const char *name,
 834                             Error **errp)
 835 {
 836     StringOutputVisitor *mo;
 837     char *string;
 838
 839     mo = string_output_visitor_new();
 840     object_property_get(obj, string_output_get_visitor(mo), name, errp);
 841     string = string_output_get_string(mo);
 842     string_output_visitor_cleanup(mo);
 843     return string;
 844 }
 845
 846 const char *object_property_get_type(Object *obj, const char *name, Error **errp)
 847 {
 848     ObjectProperty *prop = object_property_find(obj, name, errp);
 849     if (prop == NULL) {
 850         return NULL;
 851     }
 852
 853     return prop->type;
 854 }
 855
 856 Object *object_get_root(void)
 857 {
 858     static Object *root;
 859
 860     if (!root) {
 861         root = object_new("container");
 862     }
 863
 864     return root;
 865 }
 866
 867 static void object_get_child_property(Object *obj, Visitor *v, void *opaque,
 868                                       const char *name, Error **errp)
 869 {
 870     Object *child = opaque;
 871     gchar *path;
 872
 873     path = object_get_canonical_path(child);
 874     visit_type_str(v, &path, name, errp);
 875     g_free(path);
 876 }
 877
 878 static void object_finalize_child_property(Object *obj, const char *name,
 879                                            void *opaque)
 880 {
 881     Object *child = opaque;
 882
 883     object_unref(child);
 884 }
 885
 886 void object_property_add_child(Object *obj, const char *name,
 887                                Object *child, Error **errp)
 888 {
 889     gchar *type;
 890
 891     type = g_strdup_printf("child<%s>", object_get_typename(OBJECT(child)));
 892
 893     object_property_add(obj, name, type, object_get_child_property,
 894                         NULL, object_finalize_child_property, child, errp);
 895
 896     object_ref(child);
 897     g_assert(child->parent == NULL);
 898     child->parent = obj;
 899
 900     g_free(type);
 901 }
 902
 903 static void object_get_link_property(Object *obj, Visitor *v, void *opaque,
 904                                      const char *name, Error **errp)
 905 {
 906     Object **child = opaque;
 907     gchar *path;
 908
 909     if (*child) {
 910         path = object_get_canonical_path(*child);
 911         visit_type_str(v, &path, name, errp);
 912         g_free(path);
 913     } else {
 914         path = (gchar *)"";
 915         visit_type_str(v, &path, name, errp);
 916     }
 917 }
 918
 919 static void object_set_link_property(Object *obj, Visitor *v, void *opaque,
 920                                      const char *name, Error **errp)
 921 {
 922     Object **child = opaque;
 923     Object *old_target;
 924     bool ambiguous = false;
 925     const char *type;
 926     char *path;
 927     gchar *target_type;
 928
 929     type = object_property_get_type(obj, name, NULL);
 930
 931     visit_type_str(v, &path, name, errp);
 932
 933     old_target = *child;
 934     *child = NULL;
 935
 936     if (strcmp(path, "") != 0) {
 937         Object *target;
 938
 939         /* Go from link<FOO> to FOO.  */
 940         target_type = g_strndup(&type[5], strlen(type) - 6);
 941         target = object_resolve_path_type(path, target_type, &ambiguous);
 942
 943         if (ambiguous) {
 944             error_set(errp, QERR_AMBIGUOUS_PATH, path);
 945         } else if (target) {
 946             object_ref(target);
 947             *child = target;
 948         } else {
 949             target = object_resolve_path(path, &ambiguous);
 950             if (target || ambiguous) {
 951                 error_set(errp, QERR_INVALID_PARAMETER_TYPE, name, target_type);
 952             } else {
 953                 error_set(errp, QERR_DEVICE_NOT_FOUND, path);
 954             }
 955         }
 956         g_free(target_type);
 957     }
 958
 959     g_free(path);
 960
 961     if (old_target != NULL) {
 962         object_unref(old_target);
 963     }
 964 }
 965
 966 void object_property_add_link(Object *obj, const char *name,
 967                               const char *type, Object **child,
 968                               Error **errp)
 969 {
 970     gchar *full_type;
 971
 972     full_type = g_strdup_printf("link<%s>", type);
 973
 974     object_property_add(obj, name, full_type,
 975                         object_get_link_property,
 976                         object_set_link_property,
 977                         NULL, child, errp);
 978
 979     g_free(full_type);
 980 }
 981
 982 gchar *object_get_canonical_path(Object *obj)
 983 {
 984     Object *root = object_get_root();
 985     char *newpath = NULL, *path = NULL;
 986
 987     while (obj != root) {
 988         ObjectProperty *prop = NULL;
 989
 990         g_assert(obj->parent != NULL);
 991
 992         QTAILQ_FOREACH(prop, &obj->parent->properties, node) {
 993             if (!object_property_is_child(prop)) {
 994                 continue;
 995             }
 996
 997             if (prop->opaque == obj) {
 998                 if (path) {
 999                     newpath = g_strdup_printf("%s/%s", prop->name, path);
1000                     g_free(path);
1001                     path = newpath;
1002                 } else {
1003                     path = g_strdup(prop->name);
1004                 }
1005                 break;
1006             }
1007         }
1008
1009         g_assert(prop != NULL);
1010
1011         obj = obj->parent;
1012     }
1013
1014     newpath = g_strdup_printf("/%s", path);
1015     g_free(path);
1016
1017     return newpath;
1018 }
1019
1020 Object *object_resolve_path_component(Object *parent, const gchar *part)
1021 {
1022     ObjectProperty *prop = object_property_find(parent, part, NULL);
1023     if (prop == NULL) {
1024         return NULL;
1025     }
1026
1027     if (object_property_is_link(prop)) {
1028         return *(Object **)prop->opaque;
1029     } else if (object_property_is_child(prop)) {
1030         return prop->opaque;
1031     } else {
1032         return NULL;
1033     }
1034 }
1035
1036 static Object *object_resolve_abs_path(Object *parent,
1037                                           gchar **parts,
1038                                           const char *typename,
1039                                           int index)
1040 {
1041     Object *child;
1042
1043     if (parts[index] == NULL) {
1044         return object_dynamic_cast(parent, typename);
1045     }
1046
1047     if (strcmp(parts[index], "") == 0) {
1048         return object_resolve_abs_path(parent, parts, typename, index + 1);
1049     }
1050
1051     child = object_resolve_path_component(parent, parts[index]);
1052     if (!child) {
1053         return NULL;
1054     }
1055
1056     return object_resolve_abs_path(child, parts, typename, index + 1);
1057 }
1058
1059 static Object *object_resolve_partial_path(Object *parent,
1060                                               gchar **parts,
1061                                               const char *typename,
1062                                               bool *ambiguous)
1063 {
1064     Object *obj;
1065     ObjectProperty *prop;
1066
1067     obj = object_resolve_abs_path(parent, parts, typename, 0);
1068
1069     QTAILQ_FOREACH(prop, &parent->properties, node) {
1070         Object *found;
1071
1072         if (!object_property_is_child(prop)) {
1073             continue;
1074         }
1075
1076         found = object_resolve_partial_path(prop->opaque, parts,
1077                                             typename, ambiguous);
1078         if (found) {
1079             if (obj) {
1080                 if (ambiguous) {
1081                     *ambiguous = true;
1082                 }
1083                 return NULL;
1084             }
1085             obj = found;
1086         }
1087
1088         if (ambiguous && *ambiguous) {
1089             return NULL;
1090         }
1091     }
1092
1093     return obj;
1094 }
1095
1096 Object *object_resolve_path_type(const char *path, const char *typename,
1097                                  bool *ambiguous)
1098 {
1099     bool partial_path = true;
1100     Object *obj;
1101     gchar **parts;
1102
1103     parts = g_strsplit(path, "/", 0);
1104     if (parts == NULL || parts[0] == NULL) {
1105         g_strfreev(parts);
1106         return object_get_root();
1107     }
1108
1109     if (strcmp(parts[0], "") == 0) {
1110         partial_path = false;
1111     }
1112
1113     if (partial_path) {
1114         if (ambiguous) {
1115             *ambiguous = false;
1116         }
1117         obj = object_resolve_partial_path(object_get_root(), parts,
1118                                           typename, ambiguous);
1119     } else {
1120         obj = object_resolve_abs_path(object_get_root(), parts, typename, 1);
1121     }
1122
1123     g_strfreev(parts);
1124
1125     return obj;
1126 }
1127
1128 Object *object_resolve_path(const char *path, bool *ambiguous)
1129 {
1130     return object_resolve_path_type(path, TYPE_OBJECT, ambiguous);
1131 }
1132
1133 typedef struct StringProperty
1134 {
1135     char *(*get)(Object *, Error **);
1136     void (*set)(Object *, const char *, Error **);
1137 } StringProperty;
1138
1139 static void property_get_str(Object *obj, Visitor *v, void *opaque,
1140                              const char *name, Error **errp)
1141 {
1142     StringProperty *prop = opaque;
1143     char *value;
1144
1145     value = prop->get(obj, errp);
1146     if (value) {
1147         visit_type_str(v, &value, name, errp);
1148         g_free(value);
1149     }
1150 }
1151
1152 static void property_set_str(Object *obj, Visitor *v, void *opaque,
1153                              const char *name, Error **errp)
1154 {
1155     StringProperty *prop = opaque;
1156     char *value;
1157     Error *local_err = NULL;
1158
1159     visit_type_str(v, &value, name, &local_err);
1160     if (local_err) {
1161         error_propagate(errp, local_err);
1162         return;
1163     }
1164
1165     prop->set(obj, value, errp);
1166     g_free(value);
1167 }
1168
1169 static void property_release_str(Object *obj, const char *name,
1170                                  void *opaque)
1171 {
1172     StringProperty *prop = opaque;
1173     g_free(prop);
1174 }
1175
1176 void object_property_add_str(Object *obj, const char *name,
1177                            char *(*get)(Object *, Error **),
1178                            void (*set)(Object *, const char *, Error **),
1179                            Error **errp)
1180 {
1181     StringProperty *prop = g_malloc0(sizeof(*prop));
1182
1183     prop->get = get;
1184     prop->set = set;
1185
1186     object_property_add(obj, name, "string",
1187                         get ? property_get_str : NULL,
1188                         set ? property_set_str : NULL,
1189                         property_release_str,
1190                         prop, errp);
1191 }
1192
1193 typedef struct BoolProperty
1194 {
1195     bool (*get)(Object *, Error **);
1196     void (*set)(Object *, bool, Error **);
1197 } BoolProperty;
1198
1199 static void property_get_bool(Object *obj, Visitor *v, void *opaque,
1200                               const char *name, Error **errp)
1201 {
1202     BoolProperty *prop = opaque;
1203     bool value;
1204
1205     value = prop->get(obj, errp);
1206     visit_type_bool(v, &value, name, errp);
1207 }
1208
1209 static void property_set_bool(Object *obj, Visitor *v, void *opaque,
1210                               const char *name, Error **errp)
1211 {
1212     BoolProperty *prop = opaque;
1213     bool value;
1214     Error *local_err = NULL;
1215
1216     visit_type_bool(v, &value, name, &local_err);
1217     if (local_err) {
1218         error_propagate(errp, local_err);
1219         return;
1220     }
1221
1222     prop->set(obj, value, errp);
1223 }
1224
1225 static void property_release_bool(Object *obj, const char *name,
1226                                   void *opaque)
1227 {
1228     BoolProperty *prop = opaque;
1229     g_free(prop);
1230 }
1231
1232 void object_property_add_bool(Object *obj, const char *name,
1233                               bool (*get)(Object *, Error **),
1234                               void (*set)(Object *, bool, Error **),
1235                               Error **errp)
1236 {
1237     BoolProperty *prop = g_malloc0(sizeof(*prop));
1238
1239     prop->get = get;
1240     prop->set = set;
1241
1242     object_property_add(obj, name, "bool",
1243                         get ? property_get_bool : NULL,
1244                         set ? property_set_bool : NULL,
1245                         property_release_bool,
1246                         prop, errp);
1247 }
1248
1249 static char *qdev_get_type(Object *obj, Error **errp)
1250 {
1251     return g_strdup(object_get_typename(obj));
1252 }
1253
1254 static void object_instance_init(Object *obj)
1255 {
1256     object_property_add_str(obj, "type", qdev_get_type, NULL, NULL);
1257 }
1258
1259 static void register_types(void)
1260 {
1261     static TypeInfo interface_info = {
1262         .name = TYPE_INTERFACE,
1263         .class_size = sizeof(InterfaceClass),
1264         .abstract = true,
1265     };
1266
1267     static TypeInfo object_info = {
1268         .name = TYPE_OBJECT,
1269         .instance_size = sizeof(Object),
1270         .instance_init = object_instance_init,
1271         .abstract = true,
1272     };
1273
1274     type_interface = type_register_internal(&interface_info);
1275     type_register_internal(&object_info);
1276 }
1277
1278 type_init(register_types)