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