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