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         ti->class->interfaces = NULL;
 249
 250         for (e = parent->class->interfaces; e; e = e->next) {
 251             ObjectClass *iface = e->data;
 252             type_initialize_interface(ti, object_class_get_name(iface));
 253         }
 254
 255         for (i = 0; i < ti->num_interfaces; i++) {
 256             TypeImpl *t = type_get_by_name(ti->interfaces[i].typename);
 257             for (e = ti->class->interfaces; e; e = e->next) {
 258                 TypeImpl *target_type = OBJECT_CLASS(e->data)->type;
 259
 260                 if (type_is_ancestor(target_type, t)) {
 261                     break;
 262                 }
 263             }
 264
 265             if (e) {
 266                 continue;
 267             }
 268
 269             type_initialize_interface(ti, ti->interfaces[i].typename);
 270         }
 271     }
 272
 273     ti->class->type = ti;
 274
 275     while (parent) {
 276         if (parent->class_base_init) {
 277             parent->class_base_init(ti->class, ti->class_data);
 278         }
 279         parent = type_get_parent(parent);
 280     }
 281
 282     if (ti->class_init) {
 283         ti->class_init(ti->class, ti->class_data);
 284     }
 285
 286
 287 }
 288
 289 static void object_init_with_type(Object *obj, TypeImpl *ti)
 290 {
 291     if (type_has_parent(ti)) {
 292         object_init_with_type(obj, type_get_parent(ti));
 293     }
 294
 295     if (ti->instance_init) {
 296         ti->instance_init(obj);
 297     }
 298 }
 299
 300 void object_initialize_with_type(void *data, TypeImpl *type)
 301 {
 302     Object *obj = data;
 303
 304     g_assert(type != NULL);
 305     type_initialize(type);
 306
 307     g_assert(type->instance_size >= sizeof(Object));
 308     g_assert(type->abstract == false);
 309
 310     memset(obj, 0, type->instance_size);
 311     obj->class = type->class;
 312     object_ref(obj);
 313     QTAILQ_INIT(&obj->properties);
 314     object_init_with_type(obj, type);
 315 }
 316
 317 void object_initialize(void *data, const char *typename)
 318 {
 319     TypeImpl *type = type_get_by_name(typename);
 320
 321     object_initialize_with_type(data, type);
 322 }
 323
 324 static inline bool object_property_is_child(ObjectProperty *prop)
 325 {
 326     return strstart(prop->type, "child<", NULL);
 327 }
 328
 329 static inline bool object_property_is_link(ObjectProperty *prop)
 330 {
 331     return strstart(prop->type, "link<", NULL);
 332 }
 333
 334 static void object_property_del_all(Object *obj)
 335 {
 336     while (!QTAILQ_EMPTY(&obj->properties)) {
 337         ObjectProperty *prop = QTAILQ_FIRST(&obj->properties);
 338
 339         QTAILQ_REMOVE(&obj->properties, prop, node);
 340
 341         if (prop->release) {
 342             prop->release(obj, prop->name, prop->opaque);
 343         }
 344
 345         g_free(prop->name);
 346         g_free(prop->type);
 347         g_free(prop);
 348     }
 349 }
 350
 351 static void object_property_del_child(Object *obj, Object *child, Error **errp)
 352 {
 353     ObjectProperty *prop;
 354
 355     QTAILQ_FOREACH(prop, &obj->properties, node) {
 356         if (object_property_is_child(prop) && prop->opaque == child) {
 357             object_property_del(obj, prop->name, errp);
 358             break;
 359         }
 360     }
 361 }
 362
 363 void object_unparent(Object *obj)
 364 {
 365     object_ref(obj);
 366     if (obj->parent) {
 367         object_property_del_child(obj->parent, obj, NULL);
 368     }
 369     if (obj->class->unparent) {
 370         (obj->class->unparent)(obj);
 371     }
 372     object_unref(obj);
 373 }
 374
 375 static void object_deinit(Object *obj, TypeImpl *type)
 376 {
 377     if (type->instance_finalize) {
 378         type->instance_finalize(obj);
 379     }
 380
 381     if (type_has_parent(type)) {
 382         object_deinit(obj, type_get_parent(type));
 383     }
 384 }
 385
 386 static void object_finalize(void *data)
 387 {
 388     Object *obj = data;
 389     TypeImpl *ti = obj->class->type;
 390
 391     object_deinit(obj, ti);
 392     object_property_del_all(obj);
 393
 394     g_assert(obj->ref == 0);
 395     if (obj->free) {
 396         obj->free(obj);
 397     }
 398 }
 399
 400 Object *object_new_with_type(Type type)
 401 {
 402     Object *obj;
 403
 404     g_assert(type != NULL);
 405     type_initialize(type);
 406
 407     obj = g_malloc(type->instance_size);
 408     object_initialize_with_type(obj, type);
 409     obj->free = g_free;
 410
 411     return obj;
 412 }
 413
 414 Object *object_new(const char *typename)
 415 {
 416     TypeImpl *ti = type_get_by_name(typename);
 417
 418     return object_new_with_type(ti);
 419 }
 420
 421 Object *object_dynamic_cast(Object *obj, const char *typename)
 422 {
 423     if (obj && object_class_dynamic_cast(object_get_class(obj), typename)) {
 424         return obj;
 425     }
 426
 427     return NULL;
 428 }
 429
 430 Object *object_dynamic_cast_assert(Object *obj, const char *typename)
 431 {
 432     Object *inst;
 433
 434     inst = object_dynamic_cast(obj, typename);
 435
 436     if (!inst && obj) {
 437         fprintf(stderr, "Object %p is not an instance of type %s\n",
 438                 obj, typename);
 439         abort();
 440     }
 441
 442     return inst;
 443 }
 444
 445 ObjectClass *object_class_dynamic_cast(ObjectClass *class,
 446                                        const char *typename)
 447 {
 448     TypeImpl *target_type = type_get_by_name(typename);
 449     TypeImpl *type = class->type;
 450     ObjectClass *ret = NULL;
 451
 452     if (type->num_interfaces && type_is_ancestor(target_type, type_interface)) {
 453         int found = 0;
 454         GSList *i;
 455
 456         for (i = class->interfaces; i; i = i->next) {
 457             ObjectClass *target_class = i->data;
 458
 459             if (type_is_ancestor(target_class->type, target_type)) {
 460                 ret = target_class;
 461                 found++;
 462             }
 463          }
 464
 465         /* The match was ambiguous, don't allow a cast */
 466         if (found > 1) {
 467             ret = NULL;
 468         }
 469     } else if (type_is_ancestor(type, target_type)) {
 470         ret = class;
 471     }
 472
 473     return ret;
 474 }
 475
 476 ObjectClass *object_class_dynamic_cast_assert(ObjectClass *class,
 477                                               const char *typename)
 478 {
 479     ObjectClass *ret = object_class_dynamic_cast(class, typename);
 480
 481     if (!ret) {
 482         fprintf(stderr, "Object %p is not an instance of type %s\n",
 483                 class, typename);
 484         abort();
 485     }
 486
 487     return ret;
 488 }
 489
 490 const char *object_get_typename(Object *obj)
 491 {
 492     return obj->class->type->name;
 493 }
 494
 495 ObjectClass *object_get_class(Object *obj)
 496 {
 497     return obj->class;
 498 }
 499
 500 bool object_class_is_abstract(ObjectClass *klass)
 501 {
 502     return klass->type->abstract;
 503 }
 504
 505 const char *object_class_get_name(ObjectClass *klass)
 506 {
 507     return klass->type->name;
 508 }
 509
 510 ObjectClass *object_class_by_name(const char *typename)
 511 {
 512     TypeImpl *type = type_get_by_name(typename);
 513
 514     if (!type) {
 515         return NULL;
 516     }
 517
 518     type_initialize(type);
 519
 520     return type->class;
 521 }
 522
 523 ObjectClass *object_class_get_parent(ObjectClass *class)
 524 {
 525     TypeImpl *type = type_get_parent(class->type);
 526
 527     if (!type) {
 528         return NULL;
 529     }
 530
 531     type_initialize(type);
 532
 533     return type->class;
 534 }
 535
 536 typedef struct OCFData
 537 {
 538     void (*fn)(ObjectClass *klass, void *opaque);
 539     const char *implements_type;
 540     bool include_abstract;
 541     void *opaque;
 542 } OCFData;
 543
 544 static void object_class_foreach_tramp(gpointer key, gpointer value,
 545                                        gpointer opaque)
 546 {
 547     OCFData *data = opaque;
 548     TypeImpl *type = value;
 549     ObjectClass *k;
 550
 551     type_initialize(type);
 552     k = type->class;
 553
 554     if (!data->include_abstract && type->abstract) {
 555         return;
 556     }
 557
 558     if (data->implements_type &&
 559         !object_class_dynamic_cast(k, data->implements_type)) {
 560         return;
 561     }
 562
 563     data->fn(k, data->opaque);
 564 }
 565
 566 void object_class_foreach(void (*fn)(ObjectClass *klass, void *opaque),
 567                           const char *implements_type, bool include_abstract,
 568                           void *opaque)
 569 {
 570     OCFData data = { fn, implements_type, include_abstract, opaque };
 571
 572     g_hash_table_foreach(type_table_get(), object_class_foreach_tramp, &data);
 573 }
 574
 575 int object_child_foreach(Object *obj, int (*fn)(Object *child, void *opaque),
 576                          void *opaque)
 577 {
 578     ObjectProperty *prop;
 579     int ret = 0;
 580
 581     QTAILQ_FOREACH(prop, &obj->properties, node) {
 582         if (object_property_is_child(prop)) {
 583             ret = fn(prop->opaque, opaque);
 584             if (ret != 0) {
 585                 break;
 586             }
 587         }
 588     }
 589     return ret;
 590 }
 591
 592 static void object_class_get_list_tramp(ObjectClass *klass, void *opaque)
 593 {
 594     GSList **list = opaque;
 595
 596     *list = g_slist_prepend(*list, klass);
 597 }
 598
 599 GSList *object_class_get_list(const char *implements_type,
 600                               bool include_abstract)
 601 {
 602     GSList *list = NULL;
 603
 604     object_class_foreach(object_class_get_list_tramp,
 605                          implements_type, include_abstract, &list);
 606     return list;
 607 }
 608
 609 void object_ref(Object *obj)
 610 {
 611     obj->ref++;
 612 }
 613
 614 void object_unref(Object *obj)
 615 {
 616     g_assert(obj->ref > 0);
 617     obj->ref--;
 618
 619     /* parent always holds a reference to its children */
 620     if (obj->ref == 0) {
 621         object_finalize(obj);
 622     }
 623 }
 624
 625 void object_property_add(Object *obj, const char *name, const char *type,
 626                          ObjectPropertyAccessor *get,
 627                          ObjectPropertyAccessor *set,
 628                          ObjectPropertyRelease *release,
 629                          void *opaque, Error **errp)
 630 {
 631     ObjectProperty *prop = g_malloc0(sizeof(*prop));
 632
 633     prop->name = g_strdup(name);
 634     prop->type = g_strdup(type);
 635
 636     prop->get = get;
 637     prop->set = set;
 638     prop->release = release;
 639     prop->opaque = opaque;
 640
 641     QTAILQ_INSERT_TAIL(&obj->properties, prop, node);
 642 }
 643
 644 ObjectProperty *object_property_find(Object *obj, const char *name,
 645                                      Error **errp)
 646 {
 647     ObjectProperty *prop;
 648
 649     QTAILQ_FOREACH(prop, &obj->properties, node) {
 650         if (strcmp(prop->name, name) == 0) {
 651             return prop;
 652         }
 653     }
 654
 655     error_set(errp, QERR_PROPERTY_NOT_FOUND, "", name);
 656     return NULL;
 657 }
 658
 659 void object_property_del(Object *obj, const char *name, Error **errp)
 660 {
 661     ObjectProperty *prop = object_property_find(obj, name, errp);
 662     if (prop == NULL) {
 663         return;
 664     }
 665
 666     if (prop->release) {
 667         prop->release(obj, name, prop->opaque);
 668     }
 669
 670     QTAILQ_REMOVE(&obj->properties, prop, node);
 671
 672     g_free(prop->name);
 673     g_free(prop->type);
 674     g_free(prop);
 675 }
 676
 677 void object_property_get(Object *obj, Visitor *v, const char *name,
 678                          Error **errp)
 679 {
 680     ObjectProperty *prop = object_property_find(obj, name, errp);
 681     if (prop == NULL) {
 682         return;
 683     }
 684
 685     if (!prop->get) {
 686         error_set(errp, QERR_PERMISSION_DENIED);
 687     } else {
 688         prop->get(obj, v, prop->opaque, name, errp);
 689     }
 690 }
 691
 692 void object_property_set(Object *obj, Visitor *v, const char *name,
 693                          Error **errp)
 694 {
 695     ObjectProperty *prop = object_property_find(obj, name, errp);
 696     if (prop == NULL) {
 697         return;
 698     }
 699
 700     if (!prop->set) {
 701         error_set(errp, QERR_PERMISSION_DENIED);
 702     } else {
 703         prop->set(obj, v, prop->opaque, name, errp);
 704     }
 705 }
 706
 707 void object_property_set_str(Object *obj, const char *value,
 708                              const char *name, Error **errp)
 709 {
 710     QString *qstr = qstring_from_str(value);
 711     object_property_set_qobject(obj, QOBJECT(qstr), name, errp);
 712
 713     QDECREF(qstr);
 714 }
 715
 716 char *object_property_get_str(Object *obj, const char *name,
 717                               Error **errp)
 718 {
 719     QObject *ret = object_property_get_qobject(obj, name, errp);
 720     QString *qstring;
 721     char *retval;
 722
 723     if (!ret) {
 724         return NULL;
 725     }
 726     qstring = qobject_to_qstring(ret);
 727     if (!qstring) {
 728         error_set(errp, QERR_INVALID_PARAMETER_TYPE, name, "string");
 729         retval = NULL;
 730     } else {
 731         retval = g_strdup(qstring_get_str(qstring));
 732     }
 733
 734     QDECREF(qstring);
 735     return retval;
 736 }
 737
 738 void object_property_set_link(Object *obj, Object *value,
 739                               const char *name, Error **errp)
 740 {
 741     object_property_set_str(obj, object_get_canonical_path(value),
 742                             name, errp);
 743 }
 744
 745 Object *object_property_get_link(Object *obj, const char *name,
 746                                  Error **errp)
 747 {
 748     char *str = object_property_get_str(obj, name, errp);
 749     Object *target = NULL;
 750
 751     if (str && *str) {
 752         target = object_resolve_path(str, NULL);
 753         if (!target) {
 754             error_set(errp, QERR_DEVICE_NOT_FOUND, str);
 755         }
 756     }
 757
 758     g_free(str);
 759     return target;
 760 }
 761
 762 void object_property_set_bool(Object *obj, bool value,
 763                               const char *name, Error **errp)
 764 {
 765     QBool *qbool = qbool_from_int(value);
 766     object_property_set_qobject(obj, QOBJECT(qbool), name, errp);
 767
 768     QDECREF(qbool);
 769 }
 770
 771 bool object_property_get_bool(Object *obj, const char *name,
 772                               Error **errp)
 773 {
 774     QObject *ret = object_property_get_qobject(obj, name, errp);
 775     QBool *qbool;
 776     bool retval;
 777
 778     if (!ret) {
 779         return false;
 780     }
 781     qbool = qobject_to_qbool(ret);
 782     if (!qbool) {
 783         error_set(errp, QERR_INVALID_PARAMETER_TYPE, name, "boolean");
 784         retval = false;
 785     } else {
 786         retval = qbool_get_int(qbool);
 787     }
 788
 789     QDECREF(qbool);
 790     return retval;
 791 }
 792
 793 void object_property_set_int(Object *obj, int64_t value,
 794                              const char *name, Error **errp)
 795 {
 796     QInt *qint = qint_from_int(value);
 797     object_property_set_qobject(obj, QOBJECT(qint), name, errp);
 798
 799     QDECREF(qint);
 800 }
 801
 802 int64_t object_property_get_int(Object *obj, const char *name,
 803                                 Error **errp)
 804 {
 805     QObject *ret = object_property_get_qobject(obj, name, errp);
 806     QInt *qint;
 807     int64_t retval;
 808
 809     if (!ret) {
 810         return -1;
 811     }
 812     qint = qobject_to_qint(ret);
 813     if (!qint) {
 814         error_set(errp, QERR_INVALID_PARAMETER_TYPE, name, "int");
 815         retval = -1;
 816     } else {
 817         retval = qint_get_int(qint);
 818     }
 819
 820     QDECREF(qint);
 821     return retval;
 822 }
 823
 824 void object_property_parse(Object *obj, const char *string,
 825                            const char *name, Error **errp)
 826 {
 827     StringInputVisitor *mi;
 828     mi = string_input_visitor_new(string);
 829     object_property_set(obj, string_input_get_visitor(mi), name, errp);
 830
 831     string_input_visitor_cleanup(mi);
 832 }
 833
 834 char *object_property_print(Object *obj, const char *name,
 835                             Error **errp)
 836 {
 837     StringOutputVisitor *mo;
 838     char *string;
 839
 840     mo = string_output_visitor_new();
 841     object_property_get(obj, string_output_get_visitor(mo), name, errp);
 842     string = string_output_get_string(mo);
 843     string_output_visitor_cleanup(mo);
 844     return string;
 845 }
 846
 847 const char *object_property_get_type(Object *obj, const char *name, Error **errp)
 848 {
 849     ObjectProperty *prop = object_property_find(obj, name, errp);
 850     if (prop == NULL) {
 851         return NULL;
 852     }
 853
 854     return prop->type;
 855 }
 856
 857 Object *object_get_root(void)
 858 {
 859     static Object *root;
 860
 861     if (!root) {
 862         root = object_new("container");
 863     }
 864
 865     return root;
 866 }
 867
 868 static void object_get_child_property(Object *obj, Visitor *v, void *opaque,
 869                                       const char *name, Error **errp)
 870 {
 871     Object *child = opaque;
 872     gchar *path;
 873
 874     path = object_get_canonical_path(child);
 875     visit_type_str(v, &path, name, errp);
 876     g_free(path);
 877 }
 878
 879 static void object_finalize_child_property(Object *obj, const char *name,
 880                                            void *opaque)
 881 {
 882     Object *child = opaque;
 883
 884     object_unref(child);
 885 }
 886
 887 void object_property_add_child(Object *obj, const char *name,
 888                                Object *child, Error **errp)
 889 {
 890     gchar *type;
 891
 892     type = g_strdup_printf("child<%s>", object_get_typename(OBJECT(child)));
 893
 894     object_property_add(obj, name, type, object_get_child_property,
 895                         NULL, object_finalize_child_property, child, errp);
 896
 897     object_ref(child);
 898     g_assert(child->parent == NULL);
 899     child->parent = obj;
 900
 901     g_free(type);
 902 }
 903
 904 static void object_get_link_property(Object *obj, Visitor *v, void *opaque,
 905                                      const char *name, Error **errp)
 906 {
 907     Object **child = opaque;
 908     gchar *path;
 909
 910     if (*child) {
 911         path = object_get_canonical_path(*child);
 912         visit_type_str(v, &path, name, errp);
 913         g_free(path);
 914     } else {
 915         path = (gchar *)"";
 916         visit_type_str(v, &path, name, errp);
 917     }
 918 }
 919
 920 static void object_set_link_property(Object *obj, Visitor *v, void *opaque,
 921                                      const char *name, Error **errp)
 922 {
 923     Object **child = opaque;
 924     Object *old_target;
 925     bool ambiguous = false;
 926     const char *type;
 927     char *path;
 928     gchar *target_type;
 929
 930     type = object_property_get_type(obj, name, NULL);
 931
 932     visit_type_str(v, &path, name, errp);
 933
 934     old_target = *child;
 935     *child = NULL;
 936
 937     if (strcmp(path, "") != 0) {
 938         Object *target;
 939
 940         /* Go from link<FOO> to FOO.  */
 941         target_type = g_strndup(&type[5], strlen(type) - 6);
 942         target = object_resolve_path_type(path, target_type, &ambiguous);
 943
 944         if (ambiguous) {
 945             error_set(errp, QERR_AMBIGUOUS_PATH, path);
 946         } else if (target) {
 947             object_ref(target);
 948             *child = target;
 949         } else {
 950             target = object_resolve_path(path, &ambiguous);
 951             if (target || ambiguous) {
 952                 error_set(errp, QERR_INVALID_PARAMETER_TYPE, name, target_type);
 953             } else {
 954                 error_set(errp, QERR_DEVICE_NOT_FOUND, path);
 955             }
 956         }
 957         g_free(target_type);
 958     }
 959
 960     g_free(path);
 961
 962     if (old_target != NULL) {
 963         object_unref(old_target);
 964     }
 965 }
 966
 967 void object_property_add_link(Object *obj, const char *name,
 968                               const char *type, Object **child,
 969                               Error **errp)
 970 {
 971     gchar *full_type;
 972
 973     full_type = g_strdup_printf("link<%s>", type);
 974
 975     object_property_add(obj, name, full_type,
 976                         object_get_link_property,
 977                         object_set_link_property,
 978                         NULL, child, errp);
 979
 980     g_free(full_type);
 981 }
 982
 983 gchar *object_get_canonical_path(Object *obj)
 984 {
 985     Object *root = object_get_root();
 986     char *newpath = NULL, *path = NULL;
 987
 988     while (obj != root) {
 989         ObjectProperty *prop = NULL;
 990
 991         g_assert(obj->parent != NULL);
 992
 993         QTAILQ_FOREACH(prop, &obj->parent->properties, node) {
 994             if (!object_property_is_child(prop)) {
 995                 continue;
 996             }
 997
 998             if (prop->opaque == obj) {
 999                 if (path) {
1000                     newpath = g_strdup_printf("%s/%s", prop->name, path);
1001                     g_free(path);
1002                     path = newpath;
1003                 } else {
1004                     path = g_strdup(prop->name);
1005                 }
1006                 break;
1007             }
1008         }
1009
1010         g_assert(prop != NULL);
1011
1012         obj = obj->parent;
1013     }
1014
1015     newpath = g_strdup_printf("/%s", path);
1016     g_free(path);
1017
1018     return newpath;
1019 }
1020
1021 Object *object_resolve_path_component(Object *parent, const gchar *part)
1022 {
1023     ObjectProperty *prop = object_property_find(parent, part, NULL);
1024     if (prop == NULL) {
1025         return NULL;
1026     }
1027
1028     if (object_property_is_link(prop)) {
1029         return *(Object **)prop->opaque;
1030     } else if (object_property_is_child(prop)) {
1031         return prop->opaque;
1032     } else {
1033         return NULL;
1034     }
1035 }
1036
1037 static Object *object_resolve_abs_path(Object *parent,
1038                                           gchar **parts,
1039                                           const char *typename,
1040                                           int index)
1041 {
1042     Object *child;
1043
1044     if (parts[index] == NULL) {
1045         return object_dynamic_cast(parent, typename);
1046     }
1047
1048     if (strcmp(parts[index], "") == 0) {
1049         return object_resolve_abs_path(parent, parts, typename, index + 1);
1050     }
1051
1052     child = object_resolve_path_component(parent, parts[index]);
1053     if (!child) {
1054         return NULL;
1055     }
1056
1057     return object_resolve_abs_path(child, parts, typename, index + 1);
1058 }
1059
1060 static Object *object_resolve_partial_path(Object *parent,
1061                                               gchar **parts,
1062                                               const char *typename,
1063                                               bool *ambiguous)
1064 {
1065     Object *obj;
1066     ObjectProperty *prop;
1067
1068     obj = object_resolve_abs_path(parent, parts, typename, 0);
1069
1070     QTAILQ_FOREACH(prop, &parent->properties, node) {
1071         Object *found;
1072
1073         if (!object_property_is_child(prop)) {
1074             continue;
1075         }
1076
1077         found = object_resolve_partial_path(prop->opaque, parts,
1078                                             typename, ambiguous);
1079         if (found) {
1080             if (obj) {
1081                 if (ambiguous) {
1082                     *ambiguous = true;
1083                 }
1084                 return NULL;
1085             }
1086             obj = found;
1087         }
1088
1089         if (ambiguous && *ambiguous) {
1090             return NULL;
1091         }
1092     }
1093
1094     return obj;
1095 }
1096
1097 Object *object_resolve_path_type(const char *path, const char *typename,
1098                                  bool *ambiguous)
1099 {
1100     bool partial_path = true;
1101     Object *obj;
1102     gchar **parts;
1103
1104     parts = g_strsplit(path, "/", 0);
1105     if (parts == NULL || parts[0] == NULL) {
1106         g_strfreev(parts);
1107         return object_get_root();
1108     }
1109
1110     if (strcmp(parts[0], "") == 0) {
1111         partial_path = false;
1112     }
1113
1114     if (partial_path) {
1115         if (ambiguous) {
1116             *ambiguous = false;
1117         }
1118         obj = object_resolve_partial_path(object_get_root(), parts,
1119                                           typename, ambiguous);
1120     } else {
1121         obj = object_resolve_abs_path(object_get_root(), parts, typename, 1);
1122     }
1123
1124     g_strfreev(parts);
1125
1126     return obj;
1127 }
1128
1129 Object *object_resolve_path(const char *path, bool *ambiguous)
1130 {
1131     return object_resolve_path_type(path, TYPE_OBJECT, ambiguous);
1132 }
1133
1134 typedef struct StringProperty
1135 {
1136     char *(*get)(Object *, Error **);
1137     void (*set)(Object *, const char *, Error **);
1138 } StringProperty;
1139
1140 static void property_get_str(Object *obj, Visitor *v, void *opaque,
1141                              const char *name, Error **errp)
1142 {
1143     StringProperty *prop = opaque;
1144     char *value;
1145
1146     value = prop->get(obj, errp);
1147     if (value) {
1148         visit_type_str(v, &value, name, errp);
1149         g_free(value);
1150     }
1151 }
1152
1153 static void property_set_str(Object *obj, Visitor *v, void *opaque,
1154                              const char *name, Error **errp)
1155 {
1156     StringProperty *prop = opaque;
1157     char *value;
1158     Error *local_err = NULL;
1159
1160     visit_type_str(v, &value, name, &local_err);
1161     if (local_err) {
1162         error_propagate(errp, local_err);
1163         return;
1164     }
1165
1166     prop->set(obj, value, errp);
1167     g_free(value);
1168 }
1169
1170 static void property_release_str(Object *obj, const char *name,
1171                                  void *opaque)
1172 {
1173     StringProperty *prop = opaque;
1174     g_free(prop);
1175 }
1176
1177 void object_property_add_str(Object *obj, const char *name,
1178                            char *(*get)(Object *, Error **),
1179                            void (*set)(Object *, const char *, Error **),
1180                            Error **errp)
1181 {
1182     StringProperty *prop = g_malloc0(sizeof(*prop));
1183
1184     prop->get = get;
1185     prop->set = set;
1186
1187     object_property_add(obj, name, "string",
1188                         get ? property_get_str : NULL,
1189                         set ? property_set_str : NULL,
1190                         property_release_str,
1191                         prop, errp);
1192 }
1193
1194 typedef struct BoolProperty
1195 {
1196     bool (*get)(Object *, Error **);
1197     void (*set)(Object *, bool, Error **);
1198 } BoolProperty;
1199
1200 static void property_get_bool(Object *obj, Visitor *v, void *opaque,
1201                               const char *name, Error **errp)
1202 {
1203     BoolProperty *prop = opaque;
1204     bool value;
1205
1206     value = prop->get(obj, errp);
1207     visit_type_bool(v, &value, name, errp);
1208 }
1209
1210 static void property_set_bool(Object *obj, Visitor *v, void *opaque,
1211                               const char *name, Error **errp)
1212 {
1213     BoolProperty *prop = opaque;
1214     bool value;
1215     Error *local_err = NULL;
1216
1217     visit_type_bool(v, &value, name, &local_err);
1218     if (local_err) {
1219         error_propagate(errp, local_err);
1220         return;
1221     }
1222
1223     prop->set(obj, value, errp);
1224 }
1225
1226 static void property_release_bool(Object *obj, const char *name,
1227                                   void *opaque)
1228 {
1229     BoolProperty *prop = opaque;
1230     g_free(prop);
1231 }
1232
1233 void object_property_add_bool(Object *obj, const char *name,
1234                               bool (*get)(Object *, Error **),
1235                               void (*set)(Object *, bool, Error **),
1236                               Error **errp)
1237 {
1238     BoolProperty *prop = g_malloc0(sizeof(*prop));
1239
1240     prop->get = get;
1241     prop->set = set;
1242
1243     object_property_add(obj, name, "bool",
1244                         get ? property_get_bool : NULL,
1245                         set ? property_set_bool : NULL,
1246                         property_release_bool,
1247                         prop, errp);
1248 }
1249
1250 static char *qdev_get_type(Object *obj, Error **errp)
1251 {
1252     return g_strdup(object_get_typename(obj));
1253 }
1254
1255 static void object_instance_init(Object *obj)
1256 {
1257     object_property_add_str(obj, "type", qdev_get_type, NULL, NULL);
1258 }
1259
1260 static void register_types(void)
1261 {
1262     static TypeInfo interface_info = {
1263         .name = TYPE_INTERFACE,
1264         .class_size = sizeof(InterfaceClass),
1265         .abstract = true,
1266     };
1267
1268     static TypeInfo object_info = {
1269         .name = TYPE_OBJECT,
1270         .instance_size = sizeof(Object),
1271         .instance_init = object_instance_init,
1272         .abstract = true,
1273     };
1274
1275     type_interface = type_register_internal(&interface_info);
1276     type_register_internal(&object_info);
1277 }
1278
1279 type_init(register_types)