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     if (!obj->parent) {
 366         return;
 367     }
 368
 369     object_ref(obj);
 370     if (obj->class->unparent) {
 371         (obj->class->unparent)(obj);
 372     }
 373     if (obj->parent) {
 374         object_property_del_child(obj->parent, obj, NULL);
 375     }
 376     object_unref(obj);
 377 }
 378
 379 static void object_deinit(Object *obj, TypeImpl *type)
 380 {
 381     if (type->instance_finalize) {
 382         type->instance_finalize(obj);
 383     }
 384
 385     if (type_has_parent(type)) {
 386         object_deinit(obj, type_get_parent(type));
 387     }
 388 }
 389
 390 static void object_finalize(void *data)
 391 {
 392     Object *obj = data;
 393     TypeImpl *ti = obj->class->type;
 394
 395     object_deinit(obj, ti);
 396     object_property_del_all(obj);
 397
 398     g_assert(obj->ref == 0);
 399     if (obj->free) {
 400         obj->free(obj);
 401     }
 402 }
 403
 404 Object *object_new_with_type(Type type)
 405 {
 406     Object *obj;
 407
 408     g_assert(type != NULL);
 409     type_initialize(type);
 410
 411     obj = g_malloc(type->instance_size);
 412     object_initialize_with_type(obj, type);
 413     obj->free = g_free;
 414
 415     return obj;
 416 }
 417
 418 Object *object_new(const char *typename)
 419 {
 420     TypeImpl *ti = type_get_by_name(typename);
 421
 422     return object_new_with_type(ti);
 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 (!target_type) {
 457         /* target class type unknown, so fail the cast */
 458         return NULL;
 459     }
 460
 461     if (type->class->interfaces &&
 462             type_is_ancestor(target_type, type_interface)) {
 463         int found = 0;
 464         GSList *i;
 465
 466         for (i = class->interfaces; i; i = i->next) {
 467             ObjectClass *target_class = i->data;
 468
 469             if (type_is_ancestor(target_class->type, target_type)) {
 470                 ret = target_class;
 471                 found++;
 472             }
 473          }
 474
 475         /* The match was ambiguous, don't allow a cast */
 476         if (found > 1) {
 477             ret = NULL;
 478         }
 479     } else if (type_is_ancestor(type, target_type)) {
 480         ret = class;
 481     }
 482
 483     return ret;
 484 }
 485
 486 ObjectClass *object_class_dynamic_cast_assert(ObjectClass *class,
 487                                               const char *typename)
 488 {
 489     ObjectClass *ret = object_class_dynamic_cast(class, typename);
 490
 491     if (!ret) {
 492         fprintf(stderr, "Object %p is not an instance of type %s\n",
 493                 class, typename);
 494         abort();
 495     }
 496
 497     return ret;
 498 }
 499
 500 const char *object_get_typename(Object *obj)
 501 {
 502     return obj->class->type->name;
 503 }
 504
 505 ObjectClass *object_get_class(Object *obj)
 506 {
 507     return obj->class;
 508 }
 509
 510 bool object_class_is_abstract(ObjectClass *klass)
 511 {
 512     return klass->type->abstract;
 513 }
 514
 515 const char *object_class_get_name(ObjectClass *klass)
 516 {
 517     return klass->type->name;
 518 }
 519
 520 ObjectClass *object_class_by_name(const char *typename)
 521 {
 522     TypeImpl *type = type_get_by_name(typename);
 523
 524     if (!type) {
 525         return NULL;
 526     }
 527
 528     type_initialize(type);
 529
 530     return type->class;
 531 }
 532
 533 ObjectClass *object_class_get_parent(ObjectClass *class)
 534 {
 535     TypeImpl *type = type_get_parent(class->type);
 536
 537     if (!type) {
 538         return NULL;
 539     }
 540
 541     type_initialize(type);
 542
 543     return type->class;
 544 }
 545
 546 typedef struct OCFData
 547 {
 548     void (*fn)(ObjectClass *klass, void *opaque);
 549     const char *implements_type;
 550     bool include_abstract;
 551     void *opaque;
 552 } OCFData;
 553
 554 static void object_class_foreach_tramp(gpointer key, gpointer value,
 555                                        gpointer opaque)
 556 {
 557     OCFData *data = opaque;
 558     TypeImpl *type = value;
 559     ObjectClass *k;
 560
 561     type_initialize(type);
 562     k = type->class;
 563
 564     if (!data->include_abstract && type->abstract) {
 565         return;
 566     }
 567
 568     if (data->implements_type &&
 569         !object_class_dynamic_cast(k, data->implements_type)) {
 570         return;
 571     }
 572
 573     data->fn(k, data->opaque);
 574 }
 575
 576 void object_class_foreach(void (*fn)(ObjectClass *klass, void *opaque),
 577                           const char *implements_type, bool include_abstract,
 578                           void *opaque)
 579 {
 580     OCFData data = { fn, implements_type, include_abstract, opaque };
 581
 582     g_hash_table_foreach(type_table_get(), object_class_foreach_tramp, &data);
 583 }
 584
 585 int object_child_foreach(Object *obj, int (*fn)(Object *child, void *opaque),
 586                          void *opaque)
 587 {
 588     ObjectProperty *prop;
 589     int ret = 0;
 590
 591     QTAILQ_FOREACH(prop, &obj->properties, node) {
 592         if (object_property_is_child(prop)) {
 593             ret = fn(prop->opaque, opaque);
 594             if (ret != 0) {
 595                 break;
 596             }
 597         }
 598     }
 599     return ret;
 600 }
 601
 602 static void object_class_get_list_tramp(ObjectClass *klass, void *opaque)
 603 {
 604     GSList **list = opaque;
 605
 606     *list = g_slist_prepend(*list, klass);
 607 }
 608
 609 GSList *object_class_get_list(const char *implements_type,
 610                               bool include_abstract)
 611 {
 612     GSList *list = NULL;
 613
 614     object_class_foreach(object_class_get_list_tramp,
 615                          implements_type, include_abstract, &list);
 616     return list;
 617 }
 618
 619 void object_ref(Object *obj)
 620 {
 621     obj->ref++;
 622 }
 623
 624 void object_unref(Object *obj)
 625 {
 626     g_assert(obj->ref > 0);
 627     obj->ref--;
 628
 629     /* parent always holds a reference to its children */
 630     if (obj->ref == 0) {
 631         object_finalize(obj);
 632     }
 633 }
 634
 635 void object_property_add(Object *obj, const char *name, const char *type,
 636                          ObjectPropertyAccessor *get,
 637                          ObjectPropertyAccessor *set,
 638                          ObjectPropertyRelease *release,
 639                          void *opaque, Error **errp)
 640 {
 641     ObjectProperty *prop;
 642
 643     QTAILQ_FOREACH(prop, &obj->properties, node) {
 644         if (strcmp(prop->name, name) == 0) {
 645             error_setg(errp, "attempt to add duplicate property '%s'"
 646                        " to object (type '%s')", name,
 647                        object_get_typename(obj));
 648             return;
 649         }
 650     }
 651
 652     prop = g_malloc0(sizeof(*prop));
 653
 654     prop->name = g_strdup(name);
 655     prop->type = g_strdup(type);
 656
 657     prop->get = get;
 658     prop->set = set;
 659     prop->release = release;
 660     prop->opaque = opaque;
 661
 662     QTAILQ_INSERT_TAIL(&obj->properties, prop, node);
 663 }
 664
 665 ObjectProperty *object_property_find(Object *obj, const char *name,
 666                                      Error **errp)
 667 {
 668     ObjectProperty *prop;
 669
 670     QTAILQ_FOREACH(prop, &obj->properties, node) {
 671         if (strcmp(prop->name, name) == 0) {
 672             return prop;
 673         }
 674     }
 675
 676     error_set(errp, QERR_PROPERTY_NOT_FOUND, "", name);
 677     return NULL;
 678 }
 679
 680 void object_property_del(Object *obj, const char *name, Error **errp)
 681 {
 682     ObjectProperty *prop = object_property_find(obj, name, errp);
 683     if (prop == NULL) {
 684         return;
 685     }
 686
 687     if (prop->release) {
 688         prop->release(obj, name, prop->opaque);
 689     }
 690
 691     QTAILQ_REMOVE(&obj->properties, prop, node);
 692
 693     g_free(prop->name);
 694     g_free(prop->type);
 695     g_free(prop);
 696 }
 697
 698 void object_property_get(Object *obj, Visitor *v, const char *name,
 699                          Error **errp)
 700 {
 701     ObjectProperty *prop = object_property_find(obj, name, errp);
 702     if (prop == NULL) {
 703         return;
 704     }
 705
 706     if (!prop->get) {
 707         error_set(errp, QERR_PERMISSION_DENIED);
 708     } else {
 709         prop->get(obj, v, prop->opaque, name, errp);
 710     }
 711 }
 712
 713 void object_property_set(Object *obj, Visitor *v, const char *name,
 714                          Error **errp)
 715 {
 716     ObjectProperty *prop = object_property_find(obj, name, errp);
 717     if (prop == NULL) {
 718         return;
 719     }
 720
 721     if (!prop->set) {
 722         error_set(errp, QERR_PERMISSION_DENIED);
 723     } else {
 724         prop->set(obj, v, prop->opaque, name, errp);
 725     }
 726 }
 727
 728 void object_property_set_str(Object *obj, const char *value,
 729                              const char *name, Error **errp)
 730 {
 731     QString *qstr = qstring_from_str(value);
 732     object_property_set_qobject(obj, QOBJECT(qstr), name, errp);
 733
 734     QDECREF(qstr);
 735 }
 736
 737 char *object_property_get_str(Object *obj, const char *name,
 738                               Error **errp)
 739 {
 740     QObject *ret = object_property_get_qobject(obj, name, errp);
 741     QString *qstring;
 742     char *retval;
 743
 744     if (!ret) {
 745         return NULL;
 746     }
 747     qstring = qobject_to_qstring(ret);
 748     if (!qstring) {
 749         error_set(errp, QERR_INVALID_PARAMETER_TYPE, name, "string");
 750         retval = NULL;
 751     } else {
 752         retval = g_strdup(qstring_get_str(qstring));
 753     }
 754
 755     QDECREF(qstring);
 756     return retval;
 757 }
 758
 759 void object_property_set_link(Object *obj, Object *value,
 760                               const char *name, Error **errp)
 761 {
 762     object_property_set_str(obj, object_get_canonical_path(value),
 763                             name, errp);
 764 }
 765
 766 Object *object_property_get_link(Object *obj, const char *name,
 767                                  Error **errp)
 768 {
 769     char *str = object_property_get_str(obj, name, errp);
 770     Object *target = NULL;
 771
 772     if (str && *str) {
 773         target = object_resolve_path(str, NULL);
 774         if (!target) {
 775             error_set(errp, QERR_DEVICE_NOT_FOUND, str);
 776         }
 777     }
 778
 779     g_free(str);
 780     return target;
 781 }
 782
 783 void object_property_set_bool(Object *obj, bool value,
 784                               const char *name, Error **errp)
 785 {
 786     QBool *qbool = qbool_from_int(value);
 787     object_property_set_qobject(obj, QOBJECT(qbool), name, errp);
 788
 789     QDECREF(qbool);
 790 }
 791
 792 bool object_property_get_bool(Object *obj, const char *name,
 793                               Error **errp)
 794 {
 795     QObject *ret = object_property_get_qobject(obj, name, errp);
 796     QBool *qbool;
 797     bool retval;
 798
 799     if (!ret) {
 800         return false;
 801     }
 802     qbool = qobject_to_qbool(ret);
 803     if (!qbool) {
 804         error_set(errp, QERR_INVALID_PARAMETER_TYPE, name, "boolean");
 805         retval = false;
 806     } else {
 807         retval = qbool_get_int(qbool);
 808     }
 809
 810     QDECREF(qbool);
 811     return retval;
 812 }
 813
 814 void object_property_set_int(Object *obj, int64_t value,
 815                              const char *name, Error **errp)
 816 {
 817     QInt *qint = qint_from_int(value);
 818     object_property_set_qobject(obj, QOBJECT(qint), name, errp);
 819
 820     QDECREF(qint);
 821 }
 822
 823 int64_t object_property_get_int(Object *obj, const char *name,
 824                                 Error **errp)
 825 {
 826     QObject *ret = object_property_get_qobject(obj, name, errp);
 827     QInt *qint;
 828     int64_t retval;
 829
 830     if (!ret) {
 831         return -1;
 832     }
 833     qint = qobject_to_qint(ret);
 834     if (!qint) {
 835         error_set(errp, QERR_INVALID_PARAMETER_TYPE, name, "int");
 836         retval = -1;
 837     } else {
 838         retval = qint_get_int(qint);
 839     }
 840
 841     QDECREF(qint);
 842     return retval;
 843 }
 844
 845 void object_property_parse(Object *obj, const char *string,
 846                            const char *name, Error **errp)
 847 {
 848     StringInputVisitor *mi;
 849     mi = string_input_visitor_new(string);
 850     object_property_set(obj, string_input_get_visitor(mi), name, errp);
 851
 852     string_input_visitor_cleanup(mi);
 853 }
 854
 855 char *object_property_print(Object *obj, const char *name,
 856                             Error **errp)
 857 {
 858     StringOutputVisitor *mo;
 859     char *string;
 860
 861     mo = string_output_visitor_new();
 862     object_property_get(obj, string_output_get_visitor(mo), name, errp);
 863     string = string_output_get_string(mo);
 864     string_output_visitor_cleanup(mo);
 865     return string;
 866 }
 867
 868 const char *object_property_get_type(Object *obj, const char *name, Error **errp)
 869 {
 870     ObjectProperty *prop = object_property_find(obj, name, errp);
 871     if (prop == NULL) {
 872         return NULL;
 873     }
 874
 875     return prop->type;
 876 }
 877
 878 Object *object_get_root(void)
 879 {
 880     static Object *root;
 881
 882     if (!root) {
 883         root = object_new("container");
 884     }
 885
 886     return root;
 887 }
 888
 889 static void object_get_child_property(Object *obj, Visitor *v, void *opaque,
 890                                       const char *name, Error **errp)
 891 {
 892     Object *child = opaque;
 893     gchar *path;
 894
 895     path = object_get_canonical_path(child);
 896     visit_type_str(v, &path, name, errp);
 897     g_free(path);
 898 }
 899
 900 static void object_finalize_child_property(Object *obj, const char *name,
 901                                            void *opaque)
 902 {
 903     Object *child = opaque;
 904
 905     object_unref(child);
 906 }
 907
 908 void object_property_add_child(Object *obj, const char *name,
 909                                Object *child, Error **errp)
 910 {
 911     gchar *type;
 912
 913     type = g_strdup_printf("child<%s>", object_get_typename(OBJECT(child)));
 914
 915     object_property_add(obj, name, type, object_get_child_property,
 916                         NULL, object_finalize_child_property, child, errp);
 917
 918     object_ref(child);
 919     g_assert(child->parent == NULL);
 920     child->parent = obj;
 921
 922     g_free(type);
 923 }
 924
 925 static void object_get_link_property(Object *obj, Visitor *v, void *opaque,
 926                                      const char *name, Error **errp)
 927 {
 928     Object **child = opaque;
 929     gchar *path;
 930
 931     if (*child) {
 932         path = object_get_canonical_path(*child);
 933         visit_type_str(v, &path, name, errp);
 934         g_free(path);
 935     } else {
 936         path = (gchar *)"";
 937         visit_type_str(v, &path, name, errp);
 938     }
 939 }
 940
 941 static void object_set_link_property(Object *obj, Visitor *v, void *opaque,
 942                                      const char *name, Error **errp)
 943 {
 944     Object **child = opaque;
 945     Object *old_target;
 946     bool ambiguous = false;
 947     const char *type;
 948     char *path;
 949     gchar *target_type;
 950
 951     type = object_property_get_type(obj, name, NULL);
 952
 953     visit_type_str(v, &path, name, errp);
 954
 955     old_target = *child;
 956     *child = NULL;
 957
 958     if (strcmp(path, "") != 0) {
 959         Object *target;
 960
 961         /* Go from link<FOO> to FOO.  */
 962         target_type = g_strndup(&type[5], strlen(type) - 6);
 963         target = object_resolve_path_type(path, target_type, &ambiguous);
 964
 965         if (ambiguous) {
 966             error_set(errp, QERR_AMBIGUOUS_PATH, path);
 967         } else if (target) {
 968             object_ref(target);
 969             *child = target;
 970         } else {
 971             target = object_resolve_path(path, &ambiguous);
 972             if (target || ambiguous) {
 973                 error_set(errp, QERR_INVALID_PARAMETER_TYPE, name, target_type);
 974             } else {
 975                 error_set(errp, QERR_DEVICE_NOT_FOUND, path);
 976             }
 977         }
 978         g_free(target_type);
 979     }
 980
 981     g_free(path);
 982
 983     if (old_target != NULL) {
 984         object_unref(old_target);
 985     }
 986 }
 987
 988 void object_property_add_link(Object *obj, const char *name,
 989                               const char *type, Object **child,
 990                               Error **errp)
 991 {
 992     gchar *full_type;
 993
 994     full_type = g_strdup_printf("link<%s>", type);
 995
 996     object_property_add(obj, name, full_type,
 997                         object_get_link_property,
 998                         object_set_link_property,
 999                         NULL, child, errp);
1000
1001     g_free(full_type);
1002 }
1003
1004 gchar *object_get_canonical_path(Object *obj)
1005 {
1006     Object *root = object_get_root();
1007     char *newpath = NULL, *path = NULL;
1008
1009     while (obj != root) {
1010         ObjectProperty *prop = NULL;
1011
1012         g_assert(obj->parent != NULL);
1013
1014         QTAILQ_FOREACH(prop, &obj->parent->properties, node) {
1015             if (!object_property_is_child(prop)) {
1016                 continue;
1017             }
1018
1019             if (prop->opaque == obj) {
1020                 if (path) {
1021                     newpath = g_strdup_printf("%s/%s", prop->name, path);
1022                     g_free(path);
1023                     path = newpath;
1024                 } else {
1025                     path = g_strdup(prop->name);
1026                 }
1027                 break;
1028             }
1029         }
1030
1031         g_assert(prop != NULL);
1032
1033         obj = obj->parent;
1034     }
1035
1036     newpath = g_strdup_printf("/%s", path);
1037     g_free(path);
1038
1039     return newpath;
1040 }
1041
1042 Object *object_resolve_path_component(Object *parent, const gchar *part)
1043 {
1044     ObjectProperty *prop = object_property_find(parent, part, NULL);
1045     if (prop == NULL) {
1046         return NULL;
1047     }
1048
1049     if (object_property_is_link(prop)) {
1050         return *(Object **)prop->opaque;
1051     } else if (object_property_is_child(prop)) {
1052         return prop->opaque;
1053     } else {
1054         return NULL;
1055     }
1056 }
1057
1058 static Object *object_resolve_abs_path(Object *parent,
1059                                           gchar **parts,
1060                                           const char *typename,
1061                                           int index)
1062 {
1063     Object *child;
1064
1065     if (parts[index] == NULL) {
1066         return object_dynamic_cast(parent, typename);
1067     }
1068
1069     if (strcmp(parts[index], "") == 0) {
1070         return object_resolve_abs_path(parent, parts, typename, index + 1);
1071     }
1072
1073     child = object_resolve_path_component(parent, parts[index]);
1074     if (!child) {
1075         return NULL;
1076     }
1077
1078     return object_resolve_abs_path(child, parts, typename, index + 1);
1079 }
1080
1081 static Object *object_resolve_partial_path(Object *parent,
1082                                               gchar **parts,
1083                                               const char *typename,
1084                                               bool *ambiguous)
1085 {
1086     Object *obj;
1087     ObjectProperty *prop;
1088
1089     obj = object_resolve_abs_path(parent, parts, typename, 0);
1090
1091     QTAILQ_FOREACH(prop, &parent->properties, node) {
1092         Object *found;
1093
1094         if (!object_property_is_child(prop)) {
1095             continue;
1096         }
1097
1098         found = object_resolve_partial_path(prop->opaque, parts,
1099                                             typename, ambiguous);
1100         if (found) {
1101             if (obj) {
1102                 if (ambiguous) {
1103                     *ambiguous = true;
1104                 }
1105                 return NULL;
1106             }
1107             obj = found;
1108         }
1109
1110         if (ambiguous && *ambiguous) {
1111             return NULL;
1112         }
1113     }
1114
1115     return obj;
1116 }
1117
1118 Object *object_resolve_path_type(const char *path, const char *typename,
1119                                  bool *ambiguous)
1120 {
1121     Object *obj;
1122     gchar **parts;
1123
1124     parts = g_strsplit(path, "/", 0);
1125     assert(parts);
1126
1127     if (parts[0] == NULL || strcmp(parts[0], "") != 0) {
1128         if (ambiguous) {
1129             *ambiguous = false;
1130         }
1131         obj = object_resolve_partial_path(object_get_root(), parts,
1132                                           typename, ambiguous);
1133     } else {
1134         obj = object_resolve_abs_path(object_get_root(), parts, typename, 1);
1135     }
1136
1137     g_strfreev(parts);
1138
1139     return obj;
1140 }
1141
1142 Object *object_resolve_path(const char *path, bool *ambiguous)
1143 {
1144     return object_resolve_path_type(path, TYPE_OBJECT, ambiguous);
1145 }
1146
1147 typedef struct StringProperty
1148 {
1149     char *(*get)(Object *, Error **);
1150     void (*set)(Object *, const char *, Error **);
1151 } StringProperty;
1152
1153 static void property_get_str(Object *obj, Visitor *v, void *opaque,
1154                              const char *name, Error **errp)
1155 {
1156     StringProperty *prop = opaque;
1157     char *value;
1158
1159     value = prop->get(obj, errp);
1160     if (value) {
1161         visit_type_str(v, &value, name, errp);
1162         g_free(value);
1163     }
1164 }
1165
1166 static void property_set_str(Object *obj, Visitor *v, void *opaque,
1167                              const char *name, Error **errp)
1168 {
1169     StringProperty *prop = opaque;
1170     char *value;
1171     Error *local_err = NULL;
1172
1173     visit_type_str(v, &value, name, &local_err);
1174     if (local_err) {
1175         error_propagate(errp, local_err);
1176         return;
1177     }
1178
1179     prop->set(obj, value, errp);
1180     g_free(value);
1181 }
1182
1183 static void property_release_str(Object *obj, const char *name,
1184                                  void *opaque)
1185 {
1186     StringProperty *prop = opaque;
1187     g_free(prop);
1188 }
1189
1190 void object_property_add_str(Object *obj, const char *name,
1191                            char *(*get)(Object *, Error **),
1192                            void (*set)(Object *, const char *, Error **),
1193                            Error **errp)
1194 {
1195     StringProperty *prop = g_malloc0(sizeof(*prop));
1196
1197     prop->get = get;
1198     prop->set = set;
1199
1200     object_property_add(obj, name, "string",
1201                         get ? property_get_str : NULL,
1202                         set ? property_set_str : NULL,
1203                         property_release_str,
1204                         prop, errp);
1205 }
1206
1207 typedef struct BoolProperty
1208 {
1209     bool (*get)(Object *, Error **);
1210     void (*set)(Object *, bool, Error **);
1211 } BoolProperty;
1212
1213 static void property_get_bool(Object *obj, Visitor *v, void *opaque,
1214                               const char *name, Error **errp)
1215 {
1216     BoolProperty *prop = opaque;
1217     bool value;
1218
1219     value = prop->get(obj, errp);
1220     visit_type_bool(v, &value, name, errp);
1221 }
1222
1223 static void property_set_bool(Object *obj, Visitor *v, void *opaque,
1224                               const char *name, Error **errp)
1225 {
1226     BoolProperty *prop = opaque;
1227     bool value;
1228     Error *local_err = NULL;
1229
1230     visit_type_bool(v, &value, name, &local_err);
1231     if (local_err) {
1232         error_propagate(errp, local_err);
1233         return;
1234     }
1235
1236     prop->set(obj, value, errp);
1237 }
1238
1239 static void property_release_bool(Object *obj, const char *name,
1240                                   void *opaque)
1241 {
1242     BoolProperty *prop = opaque;
1243     g_free(prop);
1244 }
1245
1246 void object_property_add_bool(Object *obj, const char *name,
1247                               bool (*get)(Object *, Error **),
1248                               void (*set)(Object *, bool, Error **),
1249                               Error **errp)
1250 {
1251     BoolProperty *prop = g_malloc0(sizeof(*prop));
1252
1253     prop->get = get;
1254     prop->set = set;
1255
1256     object_property_add(obj, name, "bool",
1257                         get ? property_get_bool : NULL,
1258                         set ? property_set_bool : NULL,
1259                         property_release_bool,
1260                         prop, errp);
1261 }
1262
1263 static char *qdev_get_type(Object *obj, Error **errp)
1264 {
1265     return g_strdup(object_get_typename(obj));
1266 }
1267
1268 static void object_instance_init(Object *obj)
1269 {
1270     object_property_add_str(obj, "type", qdev_get_type, NULL, NULL);
1271 }
1272
1273 static void register_types(void)
1274 {
1275     static TypeInfo interface_info = {
1276         .name = TYPE_INTERFACE,
1277         .class_size = sizeof(InterfaceClass),
1278         .abstract = true,
1279     };
1280
1281     static TypeInfo object_info = {
1282         .name = TYPE_OBJECT,
1283         .instance_size = sizeof(Object),
1284         .instance_init = object_instance_init,
1285         .abstract = true,
1286     };
1287
1288     type_interface = type_register_internal(&interface_info);
1289     type_register_internal(&object_info);
1290 }
1291
1292 type_init(register_types)