qom/object.c

   1 /*
   2  * QEMU Object Model
   3  *
   4  * Copyright IBM, Corp. 2011
   5  *
   6  * Authors:
   7  *  Anthony Liguori   <aliguori@us.ibm.com>
   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 "hw/qdev.h"
  17 // FIXME remove above
  18
  19 #define MAX_INTERFACES 32
  20
  21 typedef struct InterfaceImpl InterfaceImpl;
  22 typedef struct TypeImpl TypeImpl;
  23
  24 struct InterfaceImpl
  25 {
  26     const char *parent;
  27     void (*interface_initfn)(ObjectClass *class, void *data);
  28     TypeImpl *type;
  29 };
  30
  31 struct TypeImpl
  32 {
  33     const char *name;
  34
  35     size_t class_size;
  36
  37     size_t instance_size;
  38
  39     void (*class_init)(ObjectClass *klass, void *data);
  40     void (*class_finalize)(ObjectClass *klass, void *data);
  41
  42     void *class_data;
  43
  44     void (*instance_init)(Object *obj);
  45     void (*instance_finalize)(Object *obj);
  46
  47     bool abstract;
  48
  49     const char *parent;
  50     TypeImpl *parent_type;
  51
  52     ObjectClass *class;
  53
  54     int num_interfaces;
  55     InterfaceImpl interfaces[MAX_INTERFACES];
  56 };
  57
  58 typedef struct Interface
  59 {
  60     Object parent;
  61     Object *obj;
  62 } Interface;
  63
  64 #define INTERFACE(obj) OBJECT_CHECK(Interface, obj, TYPE_INTERFACE)
  65
  66 static GHashTable *type_table_get(void)
  67 {
  68     static GHashTable *type_table;
  69
  70     if (type_table == NULL) {
  71         type_table = g_hash_table_new(g_str_hash, g_str_equal);
  72     }
  73
  74     return type_table;
  75 }
  76
  77 static void type_table_add(TypeImpl *ti)
  78 {
  79     g_hash_table_insert(type_table_get(), (void *)ti->name, ti);
  80 }
  81
  82 static TypeImpl *type_table_lookup(const char *name)
  83 {
  84     return g_hash_table_lookup(type_table_get(), name);
  85 }
  86
  87 TypeImpl *type_register(const TypeInfo *info)
  88 {
  89     TypeImpl *ti = g_malloc0(sizeof(*ti));
  90
  91     g_assert(info->name != NULL);
  92
  93     if (type_table_lookup(info->name) != NULL) {
  94         fprintf(stderr, "Registering `%s' which already exists\n", info->name);
  95         abort();
  96     }
  97
  98     ti->name = g_strdup(info->name);
  99     ti->parent = g_strdup(info->parent);
 100
 101     ti->class_size = info->class_size;
 102     ti->instance_size = info->instance_size;
 103
 104     ti->class_init = info->class_init;
 105     ti->class_finalize = info->class_finalize;
 106     ti->class_data = info->class_data;
 107
 108     ti->instance_init = info->instance_init;
 109     ti->instance_finalize = info->instance_finalize;
 110
 111     ti->abstract = info->abstract;
 112
 113     if (info->interfaces) {
 114         int i;
 115
 116         for (i = 0; info->interfaces[i].type; i++) {
 117             ti->interfaces[i].parent = info->interfaces[i].type;
 118             ti->interfaces[i].interface_initfn = info->interfaces[i].interface_initfn;
 119             ti->num_interfaces++;
 120         }
 121     }
 122
 123     type_table_add(ti);
 124
 125     return ti;
 126 }
 127
 128 TypeImpl *type_register_static(const TypeInfo *info)
 129 {
 130     return type_register(info);
 131 }
 132
 133 static TypeImpl *type_get_by_name(const char *name)
 134 {
 135     if (name == NULL) {
 136         return NULL;
 137     }
 138
 139     return type_table_lookup(name);
 140 }
 141
 142 static TypeImpl *type_get_parent(TypeImpl *type)
 143 {
 144     if (!type->parent_type && type->parent) {
 145         type->parent_type = type_get_by_name(type->parent);
 146         g_assert(type->parent_type != NULL);
 147     }
 148
 149     return type->parent_type;
 150 }
 151
 152 static bool type_has_parent(TypeImpl *type)
 153 {
 154     return (type->parent != NULL);
 155 }
 156
 157 static size_t type_class_get_size(TypeImpl *ti)
 158 {
 159     if (ti->class_size) {
 160         return ti->class_size;
 161     }
 162
 163     if (type_has_parent(ti)) {
 164         return type_class_get_size(type_get_parent(ti));
 165     }
 166
 167     return sizeof(ObjectClass);
 168 }
 169
 170 static void type_class_interface_init(TypeImpl *ti, InterfaceImpl *iface)
 171 {
 172     TypeInfo info = {
 173         .instance_size = sizeof(Interface),
 174         .parent = iface->parent,
 175         .class_size = sizeof(InterfaceClass),
 176         .class_init = iface->interface_initfn,
 177         .abstract = true,
 178     };
 179     char *name = g_strdup_printf("<%s::%s>", ti->name, iface->parent);
 180
 181     info.name = name;
 182     iface->type = type_register(&info);
 183     g_free(name);
 184 }
 185
 186 static void type_class_init(TypeImpl *ti)
 187 {
 188     size_t class_size = sizeof(ObjectClass);
 189     int i;
 190
 191     if (ti->class) {
 192         return;
 193     }
 194
 195     ti->class_size = type_class_get_size(ti);
 196
 197     ti->class = g_malloc0(ti->class_size);
 198     ti->class->type = ti;
 199
 200     if (type_has_parent(ti)) {
 201         TypeImpl *parent = type_get_parent(ti);
 202
 203         type_class_init(parent);
 204
 205         class_size = parent->class_size;
 206         g_assert(parent->class_size <= ti->class_size);
 207
 208         memcpy((void *)ti->class + sizeof(ObjectClass),
 209                (void *)parent->class + sizeof(ObjectClass),
 210                parent->class_size - sizeof(ObjectClass));
 211     }
 212
 213     memset((void *)ti->class + class_size, 0, ti->class_size - class_size);
 214
 215     for (i = 0; i < ti->num_interfaces; i++) {
 216         type_class_interface_init(ti, &ti->interfaces[i]);
 217     }
 218
 219     if (ti->class_init) {
 220         ti->class_init(ti->class, ti->class_data);
 221     }
 222 }
 223
 224 static void object_interface_init(Object *obj, InterfaceImpl *iface)
 225 {
 226     TypeImpl *ti = iface->type;
 227     Interface *iface_obj;
 228
 229     iface_obj = INTERFACE(object_new(ti->name));
 230     iface_obj->obj = obj;
 231
 232     obj->interfaces = g_slist_prepend(obj->interfaces, iface_obj);
 233 }
 234
 235 static void object_init_with_type(Object *obj, TypeImpl *ti)
 236 {
 237     int i;
 238
 239     if (type_has_parent(ti)) {
 240         object_init_with_type(obj, type_get_parent(ti));
 241     }
 242
 243     for (i = 0; i < ti->num_interfaces; i++) {
 244         object_interface_init(obj, &ti->interfaces[i]);
 245     }
 246
 247     if (ti->instance_init) {
 248         ti->instance_init(obj);
 249     }
 250 }
 251
 252 void object_initialize_with_type(void *data, TypeImpl *type)
 253 {
 254     Object *obj = data;
 255
 256     g_assert(type != NULL);
 257     g_assert(type->instance_size >= sizeof(ObjectClass));
 258
 259     type_class_init(type);
 260     g_assert(type->abstract == false);
 261
 262     memset(obj, 0, type->instance_size);
 263     obj->class = type->class;
 264     QTAILQ_INIT(&obj->properties);
 265     object_init_with_type(obj, type);
 266 }
 267
 268 void object_initialize(void *data, const char *typename)
 269 {
 270     TypeImpl *type = type_get_by_name(typename);
 271
 272     object_initialize_with_type(data, type);
 273 }
 274
 275 static void object_property_del_all(Object *obj)
 276 {
 277     while (!QTAILQ_EMPTY(&obj->properties)) {
 278         ObjectProperty *prop = QTAILQ_FIRST(&obj->properties);
 279
 280         QTAILQ_REMOVE(&obj->properties, prop, node);
 281
 282         if (prop->release) {
 283             prop->release(obj, prop->name, prop->opaque);
 284         }
 285
 286         g_free(prop->name);
 287         g_free(prop->type);
 288         g_free(prop);
 289     }
 290 }
 291
 292 static void object_property_del_child(Object *obj, Object *child, Error **errp)
 293 {
 294     ObjectProperty *prop;
 295
 296     QTAILQ_FOREACH(prop, &obj->properties, node) {
 297         if (!strstart(prop->type, "child<", NULL)) {
 298             continue;
 299         }
 300
 301         if (prop->opaque == child) {
 302             object_property_del(obj, prop->name, errp);
 303         }
 304     }
 305 }
 306
 307 void object_unparent(Object *obj)
 308 {
 309     if (obj->parent) {
 310         object_property_del_child(obj->parent, obj, NULL);
 311     }
 312 }
 313
 314 static void object_deinit(Object *obj, TypeImpl *type)
 315 {
 316     if (type->instance_finalize) {
 317         type->instance_finalize(obj);
 318     }
 319
 320     while (obj->interfaces) {
 321         Interface *iface_obj = obj->interfaces->data;
 322         obj->interfaces = g_slist_delete_link(obj->interfaces, obj->interfaces);
 323         object_delete(OBJECT(iface_obj));
 324     }
 325
 326     if (type_has_parent(type)) {
 327         object_deinit(obj, type_get_parent(type));
 328     }
 329
 330     object_unparent(obj);
 331 }
 332
 333 void object_finalize(void *data)
 334 {
 335     Object *obj = data;
 336     TypeImpl *ti = obj->class->type;
 337
 338     object_deinit(obj, ti);
 339     object_property_del_all(obj);
 340
 341     g_assert(obj->ref == 0);
 342 }
 343
 344 Object *object_new_with_type(Type type)
 345 {
 346     Object *obj;
 347
 348     g_assert(type != NULL);
 349
 350     obj = g_malloc(type->instance_size);
 351     object_initialize_with_type(obj, type);
 352     object_ref(obj);
 353
 354     return obj;
 355 }
 356
 357 Object *object_new(const char *typename)
 358 {
 359     TypeImpl *ti = type_get_by_name(typename);
 360
 361     return object_new_with_type(ti);
 362 }
 363
 364 void object_delete(Object *obj)
 365 {
 366     object_unref(obj);
 367     g_assert(obj->ref == 0);
 368     g_free(obj);
 369 }
 370
 371 static bool object_is_type(Object *obj, const char *typename)
 372 {
 373     TypeImpl *target_type = type_get_by_name(typename);
 374     TypeImpl *type = obj->class->type;
 375     GSList *i;
 376
 377     /* Check if typename is a direct ancestor of type */
 378     while (type) {
 379         if (type == target_type) {
 380             return true;
 381         }
 382
 383         type = type_get_parent(type);
 384     }
 385
 386     /* Check if obj has an interface of typename */
 387     for (i = obj->interfaces; i; i = i->next) {
 388         Interface *iface = i->data;
 389
 390         if (object_is_type(OBJECT(iface), typename)) {
 391             return true;
 392         }
 393     }
 394
 395     return false;
 396 }
 397
 398 Object *object_dynamic_cast(Object *obj, const char *typename)
 399 {
 400     GSList *i;
 401
 402     /* Check if typename is a direct ancestor */
 403     if (object_is_type(obj, typename)) {
 404         return obj;
 405     }
 406
 407     /* Check if obj has an interface of typename */
 408     for (i = obj->interfaces; i; i = i->next) {
 409         Interface *iface = i->data;
 410
 411         if (object_is_type(OBJECT(iface), typename)) {
 412             return OBJECT(iface);
 413         }
 414     }
 415
 416     /* Check if obj is an interface and its containing object is a direct
 417      * ancestor of typename */
 418     if (object_is_type(obj, TYPE_INTERFACE)) {
 419         Interface *iface = INTERFACE(obj);
 420
 421         if (object_is_type(iface->obj, typename)) {
 422             return iface->obj;
 423         }
 424     }
 425
 426     return NULL;
 427 }
 428
 429
 430 static void register_interface(void)
 431 {
 432     static TypeInfo interface_info = {
 433         .name = TYPE_INTERFACE,
 434         .instance_size = sizeof(Interface),
 435         .abstract = true,
 436     };
 437
 438     type_register_static(&interface_info);
 439 }
 440
 441 device_init(register_interface);
 442
 443 Object *object_dynamic_cast_assert(Object *obj, const char *typename)
 444 {
 445     Object *inst;
 446
 447     inst = object_dynamic_cast(obj, typename);
 448
 449     if (!inst) {
 450         fprintf(stderr, "Object %p is not an instance of type %s\n",
 451                 obj, typename);
 452         abort();
 453     }
 454
 455     return inst;
 456 }
 457
 458 ObjectClass *object_class_dynamic_cast(ObjectClass *class,
 459                                        const char *typename)
 460 {
 461     TypeImpl *target_type = type_get_by_name(typename);
 462     TypeImpl *type = class->type;
 463
 464     while (type) {
 465         if (type == target_type) {
 466             return class;
 467         }
 468
 469         type = type_get_parent(type);
 470     }
 471
 472     return NULL;
 473 }
 474
 475 ObjectClass *object_class_dynamic_cast_assert(ObjectClass *class,
 476                                               const char *typename)
 477 {
 478     ObjectClass *ret = object_class_dynamic_cast(class, typename);
 479
 480     if (!ret) {
 481         fprintf(stderr, "Object %p is not an instance of type %s\n",
 482                 class, typename);
 483         abort();
 484     }
 485
 486     return ret;
 487 }
 488
 489 const char *object_get_typename(Object *obj)
 490 {
 491     return obj->class->type->name;
 492 }
 493
 494 ObjectClass *object_get_class(Object *obj)
 495 {
 496     return obj->class;
 497 }
 498
 499 const char *object_class_get_name(ObjectClass *klass)
 500 {
 501     return klass->type->name;
 502 }
 503
 504 ObjectClass *object_class_by_name(const char *typename)
 505 {
 506     TypeImpl *type = type_get_by_name(typename);
 507
 508     if (!type) {
 509         return NULL;
 510     }
 511
 512     type_class_init(type);
 513
 514     return type->class;
 515 }
 516
 517 typedef struct OCFData
 518 {
 519     void (*fn)(ObjectClass *klass, void *opaque);
 520     const char *implements_type;
 521     bool include_abstract;
 522     void *opaque;
 523 } OCFData;
 524
 525 static void object_class_foreach_tramp(gpointer key, gpointer value,
 526                                        gpointer opaque)
 527 {
 528     OCFData *data = opaque;
 529     TypeImpl *type = value;
 530     ObjectClass *k;
 531
 532     type_class_init(type);
 533     k = type->class;
 534
 535     if (!data->include_abstract && type->abstract) {
 536         return;
 537     }
 538
 539     if (data->implements_type &&
 540         !object_class_dynamic_cast(k, data->implements_type)) {
 541         return;
 542     }
 543
 544     data->fn(k, data->opaque);
 545 }
 546
 547 void object_class_foreach(void (*fn)(ObjectClass *klass, void *opaque),
 548                           const char *implements_type, bool include_abstract,
 549                           void *opaque)
 550 {
 551     OCFData data = { fn, implements_type, include_abstract, opaque };
 552
 553     g_hash_table_foreach(type_table_get(), object_class_foreach_tramp, &data);
 554 }
 555
 556 void object_ref(Object *obj)
 557 {
 558     obj->ref++;
 559 }
 560
 561 void object_unref(Object *obj)
 562 {
 563     g_assert(obj->ref > 0);
 564     obj->ref--;
 565
 566     /* parent always holds a reference to its children */
 567     if (obj->ref == 0) {
 568         object_finalize(obj);
 569     }
 570 }
 571
 572 void object_property_add(Object *obj, const char *name, const char *type,
 573                          ObjectPropertyAccessor *get,
 574                          ObjectPropertyAccessor *set,
 575                          ObjectPropertyRelease *release,
 576                          void *opaque, Error **errp)
 577 {
 578     ObjectProperty *prop = g_malloc0(sizeof(*prop));
 579
 580     prop->name = g_strdup(name);
 581     prop->type = g_strdup(type);
 582
 583     prop->get = get;
 584     prop->set = set;
 585     prop->release = release;
 586     prop->opaque = opaque;
 587
 588     QTAILQ_INSERT_TAIL(&obj->properties, prop, node);
 589 }
 590
 591 static ObjectProperty *object_property_find(Object *obj, const char *name)
 592 {
 593     ObjectProperty *prop;
 594
 595     QTAILQ_FOREACH(prop, &obj->properties, node) {
 596         if (strcmp(prop->name, name) == 0) {
 597             return prop;
 598         }
 599     }
 600
 601     return NULL;
 602 }
 603
 604 void object_property_del(Object *obj, const char *name, Error **errp)
 605 {
 606     ObjectProperty *prop = object_property_find(obj, name);
 607
 608     QTAILQ_REMOVE(&obj->properties, prop, node);
 609
 610     prop->release(obj, prop->name, prop->opaque);
 611
 612     g_free(prop->name);
 613     g_free(prop->type);
 614     g_free(prop);
 615 }
 616
 617 void object_property_get(Object *obj, Visitor *v, const char *name,
 618                          Error **errp)
 619 {
 620     ObjectProperty *prop = object_property_find(obj, name);
 621
 622     if (prop == NULL) {
 623         error_set(errp, QERR_PROPERTY_NOT_FOUND, "", name);
 624         return;
 625     }
 626
 627     if (!prop->get) {
 628         error_set(errp, QERR_PERMISSION_DENIED);
 629     } else {
 630         prop->get(obj, v, prop->opaque, name, errp);
 631     }
 632 }
 633
 634 void object_property_set(Object *obj, Visitor *v, const char *name,
 635                          Error **errp)
 636 {
 637     ObjectProperty *prop = object_property_find(obj, name);
 638
 639     if (prop == NULL) {
 640         error_set(errp, QERR_PROPERTY_NOT_FOUND, "", name);
 641         return;
 642     }
 643
 644     if (!prop->set) {
 645         error_set(errp, QERR_PERMISSION_DENIED);
 646     } else {
 647         prop->set(obj, v, prop->opaque, name, errp);
 648     }
 649 }
 650
 651 const char *object_property_get_type(Object *obj, const char *name, Error **errp)
 652 {
 653     ObjectProperty *prop = object_property_find(obj, name);
 654
 655     if (prop == NULL) {
 656         error_set(errp, QERR_PROPERTY_NOT_FOUND, "", name);
 657         return NULL;
 658     }
 659
 660     return prop->type;
 661 }
 662
 663 Object *object_get_root(void)
 664 {
 665     static Object *root;
 666
 667     if (!root) {
 668         root = object_new("container");
 669     }
 670
 671     return root;
 672 }
 673
 674 static void object_get_child_property(Object *obj, Visitor *v, void *opaque,
 675                                       const char *name, Error **errp)
 676 {
 677     Object *child = opaque;
 678     gchar *path;
 679
 680     path = object_get_canonical_path(child);
 681     visit_type_str(v, &path, name, errp);
 682     g_free(path);
 683 }
 684
 685 static void object_finalize_child_property(Object *obj, const char *name,
 686                                            void *opaque)
 687 {
 688     Object *child = opaque;
 689
 690     object_unref(child);
 691 }
 692
 693 void object_property_add_child(Object *obj, const char *name,
 694                                Object *child, Error **errp)
 695 {
 696     gchar *type;
 697
 698     type = g_strdup_printf("child<%s>", object_get_typename(OBJECT(child)));
 699
 700     object_property_add(obj, name, type, object_get_child_property,
 701                         NULL, object_finalize_child_property, child, errp);
 702
 703     object_ref(child);
 704     g_assert(child->parent == NULL);
 705     child->parent = obj;
 706
 707     g_free(type);
 708 }
 709
 710 static void object_get_link_property(Object *obj, Visitor *v, void *opaque,
 711                                      const char *name, Error **errp)
 712 {
 713     Object **child = opaque;
 714     gchar *path;
 715
 716     if (*child) {
 717         path = object_get_canonical_path(*child);
 718         visit_type_str(v, &path, name, errp);
 719         g_free(path);
 720     } else {
 721         path = (gchar *)"";
 722         visit_type_str(v, &path, name, errp);
 723     }
 724 }
 725
 726 static void object_set_link_property(Object *obj, Visitor *v, void *opaque,
 727                                      const char *name, Error **errp)
 728 {
 729     Object **child = opaque;
 730     bool ambiguous = false;
 731     const char *type;
 732     char *path;
 733
 734     type = object_property_get_type(obj, name, NULL);
 735
 736     visit_type_str(v, &path, name, errp);
 737
 738     if (*child) {
 739         object_unref(*child);
 740     }
 741
 742     if (strcmp(path, "") != 0) {
 743         Object *target;
 744
 745         target = object_resolve_path(path, &ambiguous);
 746         if (target) {
 747             gchar *target_type;
 748
 749             target_type = g_strdup(&type[5]);
 750             target_type[strlen(target_type) - 2] = 0;
 751
 752             if (object_dynamic_cast(target, target_type)) {
 753                 object_ref(target);
 754                 *child = target;
 755             } else {
 756                 error_set(errp, QERR_INVALID_PARAMETER_TYPE, name, type);
 757             }
 758
 759             g_free(target_type);
 760         } else {
 761             error_set(errp, QERR_DEVICE_NOT_FOUND, path);
 762         }
 763     } else {
 764         *child = NULL;
 765     }
 766
 767     g_free(path);
 768 }
 769
 770 void object_property_add_link(Object *obj, const char *name,
 771                               const char *type, Object **child,
 772                               Error **errp)
 773 {
 774     gchar *full_type;
 775
 776     full_type = g_strdup_printf("link<%s>", type);
 777
 778     object_property_add(obj, name, full_type,
 779                         object_get_link_property,
 780                         object_set_link_property,
 781                         NULL, child, errp);
 782
 783     g_free(full_type);
 784 }
 785
 786 gchar *object_get_canonical_path(Object *obj)
 787 {
 788     Object *root = object_get_root();
 789     char *newpath = NULL, *path = NULL;
 790
 791     while (obj != root) {
 792         ObjectProperty *prop = NULL;
 793
 794         g_assert(obj->parent != NULL);
 795
 796         QTAILQ_FOREACH(prop, &obj->parent->properties, node) {
 797             if (!strstart(prop->type, "child<", NULL)) {
 798                 continue;
 799             }
 800
 801             if (prop->opaque == obj) {
 802                 if (path) {
 803                     newpath = g_strdup_printf("%s/%s", prop->name, path);
 804                     g_free(path);
 805                     path = newpath;
 806                 } else {
 807                     path = g_strdup(prop->name);
 808                 }
 809                 break;
 810             }
 811         }
 812
 813         g_assert(prop != NULL);
 814
 815         obj = obj->parent;
 816     }
 817
 818     newpath = g_strdup_printf("/%s", path);
 819     g_free(path);
 820
 821     return newpath;
 822 }
 823
 824 static Object *object_resolve_abs_path(Object *parent,
 825                                           gchar **parts,
 826                                           int index)
 827 {
 828     ObjectProperty *prop;
 829     Object *child;
 830
 831     if (parts[index] == NULL) {
 832         return parent;
 833     }
 834
 835     if (strcmp(parts[index], "") == 0) {
 836         return object_resolve_abs_path(parent, parts, index + 1);
 837     }
 838
 839     prop = object_property_find(parent, parts[index]);
 840     if (prop == NULL) {
 841         return NULL;
 842     }
 843
 844     child = NULL;
 845     if (strstart(prop->type, "link<", NULL)) {
 846         Object **pchild = prop->opaque;
 847         if (*pchild) {
 848             child = *pchild;
 849         }
 850     } else if (strstart(prop->type, "child<", NULL)) {
 851         child = prop->opaque;
 852     }
 853
 854     if (!child) {
 855         return NULL;
 856     }
 857
 858     return object_resolve_abs_path(child, parts, index + 1);
 859 }
 860
 861 static Object *object_resolve_partial_path(Object *parent,
 862                                               gchar **parts,
 863                                               bool *ambiguous)
 864 {
 865     Object *obj;
 866     ObjectProperty *prop;
 867
 868     obj = object_resolve_abs_path(parent, parts, 0);
 869
 870     QTAILQ_FOREACH(prop, &parent->properties, node) {
 871         Object *found;
 872
 873         if (!strstart(prop->type, "child<", NULL)) {
 874             continue;
 875         }
 876
 877         found = object_resolve_partial_path(prop->opaque, parts, ambiguous);
 878         if (found) {
 879             if (obj) {
 880                 if (ambiguous) {
 881                     *ambiguous = true;
 882                 }
 883                 return NULL;
 884             }
 885             obj = found;
 886         }
 887
 888         if (ambiguous && *ambiguous) {
 889             return NULL;
 890         }
 891     }
 892
 893     return obj;
 894 }
 895
 896 Object *object_resolve_path(const char *path, bool *ambiguous)
 897 {
 898     bool partial_path = true;
 899     Object *obj;
 900     gchar **parts;
 901
 902     parts = g_strsplit(path, "/", 0);
 903     if (parts == NULL || parts[0] == NULL) {
 904         g_strfreev(parts);
 905         return object_get_root();
 906     }
 907
 908     if (strcmp(parts[0], "") == 0) {
 909         partial_path = false;
 910     }
 911
 912     if (partial_path) {
 913         if (ambiguous) {
 914             *ambiguous = false;
 915         }
 916         obj = object_resolve_partial_path(object_get_root(), parts, ambiguous);
 917     } else {
 918         obj = object_resolve_abs_path(object_get_root(), parts, 1);
 919     }
 920
 921     g_strfreev(parts);
 922
 923     return obj;
 924 }
 925
 926 typedef struct StringProperty
 927 {
 928     char *(*get)(Object *, Error **);
 929     void (*set)(Object *, const char *, Error **);
 930 } StringProperty;
 931
 932 static void object_property_get_str(Object *obj, Visitor *v, void *opaque,
 933                                     const char *name, Error **errp)
 934 {
 935     StringProperty *prop = opaque;
 936     char *value;
 937
 938     value = prop->get(obj, errp);
 939     if (value) {
 940         visit_type_str(v, &value, name, errp);
 941         g_free(value);
 942     }
 943 }
 944
 945 static void object_property_set_str(Object *obj, Visitor *v, void *opaque,
 946                                   const char *name, Error **errp)
 947 {
 948     StringProperty *prop = opaque;
 949     char *value;
 950     Error *local_err = NULL;
 951
 952     visit_type_str(v, &value, name, &local_err);
 953     if (local_err) {
 954         error_propagate(errp, local_err);
 955         return;
 956     }
 957
 958     prop->set(obj, value, errp);
 959     g_free(value);
 960 }
 961
 962 static void object_property_release_str(Object *obj, const char *name,
 963                                       void *opaque)
 964 {
 965     StringProperty *prop = opaque;
 966     g_free(prop);
 967 }
 968
 969 void object_property_add_str(Object *obj, const char *name,
 970                            char *(*get)(Object *, Error **),
 971                            void (*set)(Object *, const char *, Error **),
 972                            Error **errp)
 973 {
 974     StringProperty *prop = g_malloc0(sizeof(*prop));
 975
 976     prop->get = get;
 977     prop->set = set;
 978
 979     object_property_add(obj, name, "string",
 980                         get ? object_property_get_str : NULL,
 981                         set ? object_property_set_str : NULL,
 982                         object_property_release_str,
 983                         prop, errp);
 984 }