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