xref: /openbmc/qemu/qom/object.c (revision 77a8257e)
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 "qom/object.h"
14 #include "qemu-common.h"
15 #include "qapi/visitor.h"
16 #include "qapi-visit.h"
17 #include "qapi/string-input-visitor.h"
18 #include "qapi/string-output-visitor.h"
19 #include "qapi/qmp/qerror.h"
20 #include "trace.h"
21 
22 /* TODO: replace QObject with a simpler visitor to avoid a dependency
23  * of the QOM core on QObject?  */
24 #include "qom/qom-qobject.h"
25 #include "qapi/qmp/qobject.h"
26 #include "qapi/qmp/qbool.h"
27 #include "qapi/qmp/qint.h"
28 #include "qapi/qmp/qstring.h"
29 
30 #define MAX_INTERFACES 32
31 
32 typedef struct InterfaceImpl InterfaceImpl;
33 typedef struct TypeImpl TypeImpl;
34 
35 struct InterfaceImpl
36 {
37     const char *typename;
38 };
39 
40 struct TypeImpl
41 {
42     const char *name;
43 
44     size_t class_size;
45 
46     size_t instance_size;
47 
48     void (*class_init)(ObjectClass *klass, void *data);
49     void (*class_base_init)(ObjectClass *klass, void *data);
50     void (*class_finalize)(ObjectClass *klass, void *data);
51 
52     void *class_data;
53 
54     void (*instance_init)(Object *obj);
55     void (*instance_post_init)(Object *obj);
56     void (*instance_finalize)(Object *obj);
57 
58     bool abstract;
59 
60     const char *parent;
61     TypeImpl *parent_type;
62 
63     ObjectClass *class;
64 
65     int num_interfaces;
66     InterfaceImpl interfaces[MAX_INTERFACES];
67 };
68 
69 static Type type_interface;
70 
71 static GHashTable *type_table_get(void)
72 {
73     static GHashTable *type_table;
74 
75     if (type_table == NULL) {
76         type_table = g_hash_table_new(g_str_hash, g_str_equal);
77     }
78 
79     return type_table;
80 }
81 
82 static bool enumerating_types;
83 
84 static void type_table_add(TypeImpl *ti)
85 {
86     assert(!enumerating_types);
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 static TypeImpl *type_new(const TypeInfo *info)
96 {
97     TypeImpl *ti = g_malloc0(sizeof(*ti));
98     int i;
99 
100     g_assert(info->name != NULL);
101 
102     if (type_table_lookup(info->name) != NULL) {
103         fprintf(stderr, "Registering `%s' which already exists\n", info->name);
104         abort();
105     }
106 
107     ti->name = g_strdup(info->name);
108     ti->parent = g_strdup(info->parent);
109 
110     ti->class_size = info->class_size;
111     ti->instance_size = info->instance_size;
112 
113     ti->class_init = info->class_init;
114     ti->class_base_init = info->class_base_init;
115     ti->class_finalize = info->class_finalize;
116     ti->class_data = info->class_data;
117 
118     ti->instance_init = info->instance_init;
119     ti->instance_post_init = info->instance_post_init;
120     ti->instance_finalize = info->instance_finalize;
121 
122     ti->abstract = info->abstract;
123 
124     for (i = 0; info->interfaces && info->interfaces[i].type; i++) {
125         ti->interfaces[i].typename = g_strdup(info->interfaces[i].type);
126     }
127     ti->num_interfaces = i;
128 
129     return ti;
130 }
131 
132 static TypeImpl *type_register_internal(const TypeInfo *info)
133 {
134     TypeImpl *ti;
135     ti = type_new(info);
136 
137     type_table_add(ti);
138     return ti;
139 }
140 
141 TypeImpl *type_register(const TypeInfo *info)
142 {
143     assert(info->parent);
144     return type_register_internal(info);
145 }
146 
147 TypeImpl *type_register_static(const TypeInfo *info)
148 {
149     return type_register(info);
150 }
151 
152 static TypeImpl *type_get_by_name(const char *name)
153 {
154     if (name == NULL) {
155         return NULL;
156     }
157 
158     return type_table_lookup(name);
159 }
160 
161 static TypeImpl *type_get_parent(TypeImpl *type)
162 {
163     if (!type->parent_type && type->parent) {
164         type->parent_type = type_get_by_name(type->parent);
165         g_assert(type->parent_type != NULL);
166     }
167 
168     return type->parent_type;
169 }
170 
171 static bool type_has_parent(TypeImpl *type)
172 {
173     return (type->parent != NULL);
174 }
175 
176 static size_t type_class_get_size(TypeImpl *ti)
177 {
178     if (ti->class_size) {
179         return ti->class_size;
180     }
181 
182     if (type_has_parent(ti)) {
183         return type_class_get_size(type_get_parent(ti));
184     }
185 
186     return sizeof(ObjectClass);
187 }
188 
189 static size_t type_object_get_size(TypeImpl *ti)
190 {
191     if (ti->instance_size) {
192         return ti->instance_size;
193     }
194 
195     if (type_has_parent(ti)) {
196         return type_object_get_size(type_get_parent(ti));
197     }
198 
199     return 0;
200 }
201 
202 static bool type_is_ancestor(TypeImpl *type, TypeImpl *target_type)
203 {
204     assert(target_type);
205 
206     /* Check if typename is a direct ancestor of type */
207     while (type) {
208         if (type == target_type) {
209             return true;
210         }
211 
212         type = type_get_parent(type);
213     }
214 
215     return false;
216 }
217 
218 static void type_initialize(TypeImpl *ti);
219 
220 static void type_initialize_interface(TypeImpl *ti, TypeImpl *interface_type,
221                                       TypeImpl *parent_type)
222 {
223     InterfaceClass *new_iface;
224     TypeInfo info = { };
225     TypeImpl *iface_impl;
226 
227     info.parent = parent_type->name;
228     info.name = g_strdup_printf("%s::%s", ti->name, interface_type->name);
229     info.abstract = true;
230 
231     iface_impl = type_new(&info);
232     iface_impl->parent_type = parent_type;
233     type_initialize(iface_impl);
234     g_free((char *)info.name);
235 
236     new_iface = (InterfaceClass *)iface_impl->class;
237     new_iface->concrete_class = ti->class;
238     new_iface->interface_type = interface_type;
239 
240     ti->class->interfaces = g_slist_append(ti->class->interfaces,
241                                            iface_impl->class);
242 }
243 
244 static void type_initialize(TypeImpl *ti)
245 {
246     TypeImpl *parent;
247 
248     if (ti->class) {
249         return;
250     }
251 
252     ti->class_size = type_class_get_size(ti);
253     ti->instance_size = type_object_get_size(ti);
254 
255     ti->class = g_malloc0(ti->class_size);
256 
257     parent = type_get_parent(ti);
258     if (parent) {
259         type_initialize(parent);
260         GSList *e;
261         int i;
262 
263         g_assert(parent->class_size <= ti->class_size);
264         memcpy(ti->class, parent->class, parent->class_size);
265         ti->class->interfaces = NULL;
266 
267         for (e = parent->class->interfaces; e; e = e->next) {
268             InterfaceClass *iface = e->data;
269             ObjectClass *klass = OBJECT_CLASS(iface);
270 
271             type_initialize_interface(ti, iface->interface_type, klass->type);
272         }
273 
274         for (i = 0; i < ti->num_interfaces; i++) {
275             TypeImpl *t = type_get_by_name(ti->interfaces[i].typename);
276             for (e = ti->class->interfaces; e; e = e->next) {
277                 TypeImpl *target_type = OBJECT_CLASS(e->data)->type;
278 
279                 if (type_is_ancestor(target_type, t)) {
280                     break;
281                 }
282             }
283 
284             if (e) {
285                 continue;
286             }
287 
288             type_initialize_interface(ti, t, t);
289         }
290     }
291 
292     ti->class->type = ti;
293 
294     while (parent) {
295         if (parent->class_base_init) {
296             parent->class_base_init(ti->class, ti->class_data);
297         }
298         parent = type_get_parent(parent);
299     }
300 
301     if (ti->class_init) {
302         ti->class_init(ti->class, ti->class_data);
303     }
304 }
305 
306 static void object_init_with_type(Object *obj, TypeImpl *ti)
307 {
308     if (type_has_parent(ti)) {
309         object_init_with_type(obj, type_get_parent(ti));
310     }
311 
312     if (ti->instance_init) {
313         ti->instance_init(obj);
314     }
315 }
316 
317 static void object_post_init_with_type(Object *obj, TypeImpl *ti)
318 {
319     if (ti->instance_post_init) {
320         ti->instance_post_init(obj);
321     }
322 
323     if (type_has_parent(ti)) {
324         object_post_init_with_type(obj, type_get_parent(ti));
325     }
326 }
327 
328 void object_initialize_with_type(void *data, size_t size, TypeImpl *type)
329 {
330     Object *obj = data;
331 
332     g_assert(type != NULL);
333     type_initialize(type);
334 
335     g_assert(type->instance_size >= sizeof(Object));
336     g_assert(type->abstract == false);
337     g_assert(size >= type->instance_size);
338 
339     memset(obj, 0, type->instance_size);
340     obj->class = type->class;
341     object_ref(obj);
342     QTAILQ_INIT(&obj->properties);
343     object_init_with_type(obj, type);
344     object_post_init_with_type(obj, type);
345 }
346 
347 void object_initialize(void *data, size_t size, const char *typename)
348 {
349     TypeImpl *type = type_get_by_name(typename);
350 
351     object_initialize_with_type(data, size, type);
352 }
353 
354 static inline bool object_property_is_child(ObjectProperty *prop)
355 {
356     return strstart(prop->type, "child<", NULL);
357 }
358 
359 static void object_property_del_all(Object *obj)
360 {
361     while (!QTAILQ_EMPTY(&obj->properties)) {
362         ObjectProperty *prop = QTAILQ_FIRST(&obj->properties);
363 
364         QTAILQ_REMOVE(&obj->properties, prop, node);
365 
366         if (prop->release) {
367             prop->release(obj, prop->name, prop->opaque);
368         }
369 
370         g_free(prop->name);
371         g_free(prop->type);
372         g_free(prop->description);
373         g_free(prop);
374     }
375 }
376 
377 static void object_property_del_child(Object *obj, Object *child, Error **errp)
378 {
379     ObjectProperty *prop;
380 
381     QTAILQ_FOREACH(prop, &obj->properties, node) {
382         if (object_property_is_child(prop) && prop->opaque == child) {
383             object_property_del(obj, prop->name, errp);
384             break;
385         }
386     }
387 }
388 
389 void object_unparent(Object *obj)
390 {
391     if (obj->parent) {
392         object_property_del_child(obj->parent, obj, NULL);
393     }
394 }
395 
396 static void object_deinit(Object *obj, TypeImpl *type)
397 {
398     if (type->instance_finalize) {
399         type->instance_finalize(obj);
400     }
401 
402     if (type_has_parent(type)) {
403         object_deinit(obj, type_get_parent(type));
404     }
405 }
406 
407 static void object_finalize(void *data)
408 {
409     Object *obj = data;
410     TypeImpl *ti = obj->class->type;
411 
412     object_property_del_all(obj);
413     object_deinit(obj, ti);
414 
415     g_assert(obj->ref == 0);
416     if (obj->free) {
417         obj->free(obj);
418     }
419 }
420 
421 Object *object_new_with_type(Type type)
422 {
423     Object *obj;
424 
425     g_assert(type != NULL);
426     type_initialize(type);
427 
428     obj = g_malloc(type->instance_size);
429     object_initialize_with_type(obj, type->instance_size, type);
430     obj->free = g_free;
431 
432     return obj;
433 }
434 
435 Object *object_new(const char *typename)
436 {
437     TypeImpl *ti = type_get_by_name(typename);
438 
439     return object_new_with_type(ti);
440 }
441 
442 Object *object_dynamic_cast(Object *obj, const char *typename)
443 {
444     if (obj && object_class_dynamic_cast(object_get_class(obj), typename)) {
445         return obj;
446     }
447 
448     return NULL;
449 }
450 
451 Object *object_dynamic_cast_assert(Object *obj, const char *typename,
452                                    const char *file, int line, const char *func)
453 {
454     trace_object_dynamic_cast_assert(obj ? obj->class->type->name : "(null)",
455                                      typename, file, line, func);
456 
457 #ifdef CONFIG_QOM_CAST_DEBUG
458     int i;
459     Object *inst;
460 
461     for (i = 0; obj && i < OBJECT_CLASS_CAST_CACHE; i++) {
462         if (obj->class->object_cast_cache[i] == typename) {
463             goto out;
464         }
465     }
466 
467     inst = object_dynamic_cast(obj, typename);
468 
469     if (!inst && obj) {
470         fprintf(stderr, "%s:%d:%s: Object %p is not an instance of type %s\n",
471                 file, line, func, obj, typename);
472         abort();
473     }
474 
475     assert(obj == inst);
476 
477     if (obj && obj == inst) {
478         for (i = 1; i < OBJECT_CLASS_CAST_CACHE; i++) {
479             obj->class->object_cast_cache[i - 1] =
480                     obj->class->object_cast_cache[i];
481         }
482         obj->class->object_cast_cache[i - 1] = typename;
483     }
484 
485 out:
486 #endif
487     return obj;
488 }
489 
490 ObjectClass *object_class_dynamic_cast(ObjectClass *class,
491                                        const char *typename)
492 {
493     ObjectClass *ret = NULL;
494     TypeImpl *target_type;
495     TypeImpl *type;
496 
497     if (!class) {
498         return NULL;
499     }
500 
501     /* A simple fast path that can trigger a lot for leaf classes.  */
502     type = class->type;
503     if (type->name == typename) {
504         return class;
505     }
506 
507     target_type = type_get_by_name(typename);
508     if (!target_type) {
509         /* target class type unknown, so fail the cast */
510         return NULL;
511     }
512 
513     if (type->class->interfaces &&
514             type_is_ancestor(target_type, type_interface)) {
515         int found = 0;
516         GSList *i;
517 
518         for (i = class->interfaces; i; i = i->next) {
519             ObjectClass *target_class = i->data;
520 
521             if (type_is_ancestor(target_class->type, target_type)) {
522                 ret = target_class;
523                 found++;
524             }
525          }
526 
527         /* The match was ambiguous, don't allow a cast */
528         if (found > 1) {
529             ret = NULL;
530         }
531     } else if (type_is_ancestor(type, target_type)) {
532         ret = class;
533     }
534 
535     return ret;
536 }
537 
538 ObjectClass *object_class_dynamic_cast_assert(ObjectClass *class,
539                                               const char *typename,
540                                               const char *file, int line,
541                                               const char *func)
542 {
543     ObjectClass *ret;
544 
545     trace_object_class_dynamic_cast_assert(class ? class->type->name : "(null)",
546                                            typename, file, line, func);
547 
548 #ifdef CONFIG_QOM_CAST_DEBUG
549     int i;
550 
551     for (i = 0; class && i < OBJECT_CLASS_CAST_CACHE; i++) {
552         if (class->class_cast_cache[i] == typename) {
553             ret = class;
554             goto out;
555         }
556     }
557 #else
558     if (!class || !class->interfaces) {
559         return class;
560     }
561 #endif
562 
563     ret = object_class_dynamic_cast(class, typename);
564     if (!ret && class) {
565         fprintf(stderr, "%s:%d:%s: Object %p is not an instance of type %s\n",
566                 file, line, func, class, typename);
567         abort();
568     }
569 
570 #ifdef CONFIG_QOM_CAST_DEBUG
571     if (class && ret == class) {
572         for (i = 1; i < OBJECT_CLASS_CAST_CACHE; i++) {
573             class->class_cast_cache[i - 1] = class->class_cast_cache[i];
574         }
575         class->class_cast_cache[i - 1] = typename;
576     }
577 out:
578 #endif
579     return ret;
580 }
581 
582 const char *object_get_typename(Object *obj)
583 {
584     return obj->class->type->name;
585 }
586 
587 ObjectClass *object_get_class(Object *obj)
588 {
589     return obj->class;
590 }
591 
592 bool object_class_is_abstract(ObjectClass *klass)
593 {
594     return klass->type->abstract;
595 }
596 
597 const char *object_class_get_name(ObjectClass *klass)
598 {
599     return klass->type->name;
600 }
601 
602 ObjectClass *object_class_by_name(const char *typename)
603 {
604     TypeImpl *type = type_get_by_name(typename);
605 
606     if (!type) {
607         return NULL;
608     }
609 
610     type_initialize(type);
611 
612     return type->class;
613 }
614 
615 ObjectClass *object_class_get_parent(ObjectClass *class)
616 {
617     TypeImpl *type = type_get_parent(class->type);
618 
619     if (!type) {
620         return NULL;
621     }
622 
623     type_initialize(type);
624 
625     return type->class;
626 }
627 
628 typedef struct OCFData
629 {
630     void (*fn)(ObjectClass *klass, void *opaque);
631     const char *implements_type;
632     bool include_abstract;
633     void *opaque;
634 } OCFData;
635 
636 static void object_class_foreach_tramp(gpointer key, gpointer value,
637                                        gpointer opaque)
638 {
639     OCFData *data = opaque;
640     TypeImpl *type = value;
641     ObjectClass *k;
642 
643     type_initialize(type);
644     k = type->class;
645 
646     if (!data->include_abstract && type->abstract) {
647         return;
648     }
649 
650     if (data->implements_type &&
651         !object_class_dynamic_cast(k, data->implements_type)) {
652         return;
653     }
654 
655     data->fn(k, data->opaque);
656 }
657 
658 void object_class_foreach(void (*fn)(ObjectClass *klass, void *opaque),
659                           const char *implements_type, bool include_abstract,
660                           void *opaque)
661 {
662     OCFData data = { fn, implements_type, include_abstract, opaque };
663 
664     enumerating_types = true;
665     g_hash_table_foreach(type_table_get(), object_class_foreach_tramp, &data);
666     enumerating_types = false;
667 }
668 
669 int object_child_foreach(Object *obj, int (*fn)(Object *child, void *opaque),
670                          void *opaque)
671 {
672     ObjectProperty *prop, *next;
673     int ret = 0;
674 
675     QTAILQ_FOREACH_SAFE(prop, &obj->properties, node, next) {
676         if (object_property_is_child(prop)) {
677             ret = fn(prop->opaque, opaque);
678             if (ret != 0) {
679                 break;
680             }
681         }
682     }
683     return ret;
684 }
685 
686 static void object_class_get_list_tramp(ObjectClass *klass, void *opaque)
687 {
688     GSList **list = opaque;
689 
690     *list = g_slist_prepend(*list, klass);
691 }
692 
693 GSList *object_class_get_list(const char *implements_type,
694                               bool include_abstract)
695 {
696     GSList *list = NULL;
697 
698     object_class_foreach(object_class_get_list_tramp,
699                          implements_type, include_abstract, &list);
700     return list;
701 }
702 
703 void object_ref(Object *obj)
704 {
705     if (!obj) {
706         return;
707     }
708      atomic_inc(&obj->ref);
709 }
710 
711 void object_unref(Object *obj)
712 {
713     if (!obj) {
714         return;
715     }
716     g_assert(obj->ref > 0);
717 
718     /* parent always holds a reference to its children */
719     if (atomic_fetch_dec(&obj->ref) == 1) {
720         object_finalize(obj);
721     }
722 }
723 
724 ObjectProperty *
725 object_property_add(Object *obj, const char *name, const char *type,
726                     ObjectPropertyAccessor *get,
727                     ObjectPropertyAccessor *set,
728                     ObjectPropertyRelease *release,
729                     void *opaque, Error **errp)
730 {
731     ObjectProperty *prop;
732     size_t name_len = strlen(name);
733 
734     if (name_len >= 3 && !memcmp(name + name_len - 3, "[*]", 4)) {
735         int i;
736         ObjectProperty *ret;
737         char *name_no_array = g_strdup(name);
738 
739         name_no_array[name_len - 3] = '\0';
740         for (i = 0; ; ++i) {
741             char *full_name = g_strdup_printf("%s[%d]", name_no_array, i);
742 
743             ret = object_property_add(obj, full_name, type, get, set,
744                                       release, opaque, NULL);
745             g_free(full_name);
746             if (ret) {
747                 break;
748             }
749         }
750         g_free(name_no_array);
751         return ret;
752     }
753 
754     QTAILQ_FOREACH(prop, &obj->properties, node) {
755         if (strcmp(prop->name, name) == 0) {
756             error_setg(errp, "attempt to add duplicate property '%s'"
757                        " to object (type '%s')", name,
758                        object_get_typename(obj));
759             return NULL;
760         }
761     }
762 
763     prop = g_malloc0(sizeof(*prop));
764 
765     prop->name = g_strdup(name);
766     prop->type = g_strdup(type);
767 
768     prop->get = get;
769     prop->set = set;
770     prop->release = release;
771     prop->opaque = opaque;
772 
773     QTAILQ_INSERT_TAIL(&obj->properties, prop, node);
774     return prop;
775 }
776 
777 ObjectProperty *object_property_find(Object *obj, const char *name,
778                                      Error **errp)
779 {
780     ObjectProperty *prop;
781 
782     QTAILQ_FOREACH(prop, &obj->properties, node) {
783         if (strcmp(prop->name, name) == 0) {
784             return prop;
785         }
786     }
787 
788     error_setg(errp, "Property '.%s' not found", name);
789     return NULL;
790 }
791 
792 void object_property_del(Object *obj, const char *name, Error **errp)
793 {
794     ObjectProperty *prop = object_property_find(obj, name, errp);
795     if (prop == NULL) {
796         return;
797     }
798 
799     if (prop->release) {
800         prop->release(obj, name, prop->opaque);
801     }
802 
803     QTAILQ_REMOVE(&obj->properties, prop, node);
804 
805     g_free(prop->name);
806     g_free(prop->type);
807     g_free(prop->description);
808     g_free(prop);
809 }
810 
811 void object_property_get(Object *obj, Visitor *v, const char *name,
812                          Error **errp)
813 {
814     ObjectProperty *prop = object_property_find(obj, name, errp);
815     if (prop == NULL) {
816         return;
817     }
818 
819     if (!prop->get) {
820         error_set(errp, QERR_PERMISSION_DENIED);
821     } else {
822         prop->get(obj, v, prop->opaque, name, errp);
823     }
824 }
825 
826 void object_property_set(Object *obj, Visitor *v, const char *name,
827                          Error **errp)
828 {
829     ObjectProperty *prop = object_property_find(obj, name, errp);
830     if (prop == NULL) {
831         return;
832     }
833 
834     if (!prop->set) {
835         error_set(errp, QERR_PERMISSION_DENIED);
836     } else {
837         prop->set(obj, v, prop->opaque, name, errp);
838     }
839 }
840 
841 void object_property_set_str(Object *obj, const char *value,
842                              const char *name, Error **errp)
843 {
844     QString *qstr = qstring_from_str(value);
845     object_property_set_qobject(obj, QOBJECT(qstr), name, errp);
846 
847     QDECREF(qstr);
848 }
849 
850 char *object_property_get_str(Object *obj, const char *name,
851                               Error **errp)
852 {
853     QObject *ret = object_property_get_qobject(obj, name, errp);
854     QString *qstring;
855     char *retval;
856 
857     if (!ret) {
858         return NULL;
859     }
860     qstring = qobject_to_qstring(ret);
861     if (!qstring) {
862         error_set(errp, QERR_INVALID_PARAMETER_TYPE, name, "string");
863         retval = NULL;
864     } else {
865         retval = g_strdup(qstring_get_str(qstring));
866     }
867 
868     QDECREF(qstring);
869     return retval;
870 }
871 
872 void object_property_set_link(Object *obj, Object *value,
873                               const char *name, Error **errp)
874 {
875     if (value) {
876         gchar *path = object_get_canonical_path(value);
877         object_property_set_str(obj, path, name, errp);
878         g_free(path);
879     } else {
880         object_property_set_str(obj, "", name, errp);
881     }
882 }
883 
884 Object *object_property_get_link(Object *obj, const char *name,
885                                  Error **errp)
886 {
887     char *str = object_property_get_str(obj, name, errp);
888     Object *target = NULL;
889 
890     if (str && *str) {
891         target = object_resolve_path(str, NULL);
892         if (!target) {
893             error_set(errp, QERR_DEVICE_NOT_FOUND, str);
894         }
895     }
896 
897     g_free(str);
898     return target;
899 }
900 
901 void object_property_set_bool(Object *obj, bool value,
902                               const char *name, Error **errp)
903 {
904     QBool *qbool = qbool_from_int(value);
905     object_property_set_qobject(obj, QOBJECT(qbool), name, errp);
906 
907     QDECREF(qbool);
908 }
909 
910 bool object_property_get_bool(Object *obj, const char *name,
911                               Error **errp)
912 {
913     QObject *ret = object_property_get_qobject(obj, name, errp);
914     QBool *qbool;
915     bool retval;
916 
917     if (!ret) {
918         return false;
919     }
920     qbool = qobject_to_qbool(ret);
921     if (!qbool) {
922         error_set(errp, QERR_INVALID_PARAMETER_TYPE, name, "boolean");
923         retval = false;
924     } else {
925         retval = qbool_get_int(qbool);
926     }
927 
928     QDECREF(qbool);
929     return retval;
930 }
931 
932 void object_property_set_int(Object *obj, int64_t value,
933                              const char *name, Error **errp)
934 {
935     QInt *qint = qint_from_int(value);
936     object_property_set_qobject(obj, QOBJECT(qint), name, errp);
937 
938     QDECREF(qint);
939 }
940 
941 int64_t object_property_get_int(Object *obj, const char *name,
942                                 Error **errp)
943 {
944     QObject *ret = object_property_get_qobject(obj, name, errp);
945     QInt *qint;
946     int64_t retval;
947 
948     if (!ret) {
949         return -1;
950     }
951     qint = qobject_to_qint(ret);
952     if (!qint) {
953         error_set(errp, QERR_INVALID_PARAMETER_TYPE, name, "int");
954         retval = -1;
955     } else {
956         retval = qint_get_int(qint);
957     }
958 
959     QDECREF(qint);
960     return retval;
961 }
962 
963 int object_property_get_enum(Object *obj, const char *name,
964                              const char *strings[], Error **errp)
965 {
966     StringOutputVisitor *sov;
967     StringInputVisitor *siv;
968     char *str;
969     int ret;
970 
971     sov = string_output_visitor_new(false);
972     object_property_get(obj, string_output_get_visitor(sov), name, errp);
973     str = string_output_get_string(sov);
974     siv = string_input_visitor_new(str);
975     string_output_visitor_cleanup(sov);
976     visit_type_enum(string_input_get_visitor(siv),
977                     &ret, strings, NULL, name, errp);
978 
979     g_free(str);
980     string_input_visitor_cleanup(siv);
981 
982     return ret;
983 }
984 
985 void object_property_get_uint16List(Object *obj, const char *name,
986                                     uint16List **list, Error **errp)
987 {
988     StringOutputVisitor *ov;
989     StringInputVisitor *iv;
990     char *str;
991 
992     ov = string_output_visitor_new(false);
993     object_property_get(obj, string_output_get_visitor(ov),
994                         name, errp);
995     str = string_output_get_string(ov);
996     iv = string_input_visitor_new(str);
997     visit_type_uint16List(string_input_get_visitor(iv),
998                           list, NULL, errp);
999 
1000     g_free(str);
1001     string_output_visitor_cleanup(ov);
1002     string_input_visitor_cleanup(iv);
1003 }
1004 
1005 void object_property_parse(Object *obj, const char *string,
1006                            const char *name, Error **errp)
1007 {
1008     StringInputVisitor *mi;
1009     mi = string_input_visitor_new(string);
1010     object_property_set(obj, string_input_get_visitor(mi), name, errp);
1011 
1012     string_input_visitor_cleanup(mi);
1013 }
1014 
1015 char *object_property_print(Object *obj, const char *name, bool human,
1016                             Error **errp)
1017 {
1018     StringOutputVisitor *mo;
1019     char *string = NULL;
1020     Error *local_err = NULL;
1021 
1022     mo = string_output_visitor_new(human);
1023     object_property_get(obj, string_output_get_visitor(mo), name, &local_err);
1024     if (local_err) {
1025         error_propagate(errp, local_err);
1026         goto out;
1027     }
1028 
1029     string = string_output_get_string(mo);
1030 
1031 out:
1032     string_output_visitor_cleanup(mo);
1033     return string;
1034 }
1035 
1036 const char *object_property_get_type(Object *obj, const char *name, Error **errp)
1037 {
1038     ObjectProperty *prop = object_property_find(obj, name, errp);
1039     if (prop == NULL) {
1040         return NULL;
1041     }
1042 
1043     return prop->type;
1044 }
1045 
1046 Object *object_get_root(void)
1047 {
1048     static Object *root;
1049 
1050     if (!root) {
1051         root = object_new("container");
1052     }
1053 
1054     return root;
1055 }
1056 
1057 static void object_get_child_property(Object *obj, Visitor *v, void *opaque,
1058                                       const char *name, Error **errp)
1059 {
1060     Object *child = opaque;
1061     gchar *path;
1062 
1063     path = object_get_canonical_path(child);
1064     visit_type_str(v, &path, name, errp);
1065     g_free(path);
1066 }
1067 
1068 static Object *object_resolve_child_property(Object *parent, void *opaque, const gchar *part)
1069 {
1070     return opaque;
1071 }
1072 
1073 static void object_finalize_child_property(Object *obj, const char *name,
1074                                            void *opaque)
1075 {
1076     Object *child = opaque;
1077 
1078     if (child->class->unparent) {
1079         (child->class->unparent)(child);
1080     }
1081     child->parent = NULL;
1082     object_unref(child);
1083 }
1084 
1085 void object_property_add_child(Object *obj, const char *name,
1086                                Object *child, Error **errp)
1087 {
1088     Error *local_err = NULL;
1089     gchar *type;
1090     ObjectProperty *op;
1091 
1092     if (child->parent != NULL) {
1093         error_setg(errp, "child object is already parented");
1094         return;
1095     }
1096 
1097     type = g_strdup_printf("child<%s>", object_get_typename(OBJECT(child)));
1098 
1099     op = object_property_add(obj, name, type, object_get_child_property, NULL,
1100                              object_finalize_child_property, child, &local_err);
1101     if (local_err) {
1102         error_propagate(errp, local_err);
1103         goto out;
1104     }
1105 
1106     op->resolve = object_resolve_child_property;
1107     object_ref(child);
1108     child->parent = obj;
1109 
1110 out:
1111     g_free(type);
1112 }
1113 
1114 void object_property_allow_set_link(Object *obj, const char *name,
1115                                     Object *val, Error **errp)
1116 {
1117     /* Allow the link to be set, always */
1118 }
1119 
1120 typedef struct {
1121     Object **child;
1122     void (*check)(Object *, const char *, Object *, Error **);
1123     ObjectPropertyLinkFlags flags;
1124 } LinkProperty;
1125 
1126 static void object_get_link_property(Object *obj, Visitor *v, void *opaque,
1127                                      const char *name, Error **errp)
1128 {
1129     LinkProperty *lprop = opaque;
1130     Object **child = lprop->child;
1131     gchar *path;
1132 
1133     if (*child) {
1134         path = object_get_canonical_path(*child);
1135         visit_type_str(v, &path, name, errp);
1136         g_free(path);
1137     } else {
1138         path = (gchar *)"";
1139         visit_type_str(v, &path, name, errp);
1140     }
1141 }
1142 
1143 /*
1144  * object_resolve_link:
1145  *
1146  * Lookup an object and ensure its type matches the link property type.  This
1147  * is similar to object_resolve_path() except type verification against the
1148  * link property is performed.
1149  *
1150  * Returns: The matched object or NULL on path lookup failures.
1151  */
1152 static Object *object_resolve_link(Object *obj, const char *name,
1153                                    const char *path, Error **errp)
1154 {
1155     const char *type;
1156     gchar *target_type;
1157     bool ambiguous = false;
1158     Object *target;
1159 
1160     /* Go from link<FOO> to FOO.  */
1161     type = object_property_get_type(obj, name, NULL);
1162     target_type = g_strndup(&type[5], strlen(type) - 6);
1163     target = object_resolve_path_type(path, target_type, &ambiguous);
1164 
1165     if (ambiguous) {
1166         error_set(errp, ERROR_CLASS_GENERIC_ERROR,
1167                   "Path '%s' does not uniquely identify an object", path);
1168     } else if (!target) {
1169         target = object_resolve_path(path, &ambiguous);
1170         if (target || ambiguous) {
1171             error_set(errp, QERR_INVALID_PARAMETER_TYPE, name, target_type);
1172         } else {
1173             error_set(errp, QERR_DEVICE_NOT_FOUND, path);
1174         }
1175         target = NULL;
1176     }
1177     g_free(target_type);
1178 
1179     return target;
1180 }
1181 
1182 static void object_set_link_property(Object *obj, Visitor *v, void *opaque,
1183                                      const char *name, Error **errp)
1184 {
1185     Error *local_err = NULL;
1186     LinkProperty *prop = opaque;
1187     Object **child = prop->child;
1188     Object *old_target = *child;
1189     Object *new_target = NULL;
1190     char *path = NULL;
1191 
1192     visit_type_str(v, &path, name, &local_err);
1193 
1194     if (!local_err && strcmp(path, "") != 0) {
1195         new_target = object_resolve_link(obj, name, path, &local_err);
1196     }
1197 
1198     g_free(path);
1199     if (local_err) {
1200         error_propagate(errp, local_err);
1201         return;
1202     }
1203 
1204     prop->check(obj, name, new_target, &local_err);
1205     if (local_err) {
1206         error_propagate(errp, local_err);
1207         return;
1208     }
1209 
1210     object_ref(new_target);
1211     *child = new_target;
1212     object_unref(old_target);
1213 }
1214 
1215 static Object *object_resolve_link_property(Object *parent, void *opaque, const gchar *part)
1216 {
1217     LinkProperty *lprop = opaque;
1218 
1219     return *lprop->child;
1220 }
1221 
1222 static void object_release_link_property(Object *obj, const char *name,
1223                                          void *opaque)
1224 {
1225     LinkProperty *prop = opaque;
1226 
1227     if ((prop->flags & OBJ_PROP_LINK_UNREF_ON_RELEASE) && *prop->child) {
1228         object_unref(*prop->child);
1229     }
1230     g_free(prop);
1231 }
1232 
1233 void object_property_add_link(Object *obj, const char *name,
1234                               const char *type, Object **child,
1235                               void (*check)(Object *, const char *,
1236                                             Object *, Error **),
1237                               ObjectPropertyLinkFlags flags,
1238                               Error **errp)
1239 {
1240     Error *local_err = NULL;
1241     LinkProperty *prop = g_malloc(sizeof(*prop));
1242     gchar *full_type;
1243     ObjectProperty *op;
1244 
1245     prop->child = child;
1246     prop->check = check;
1247     prop->flags = flags;
1248 
1249     full_type = g_strdup_printf("link<%s>", type);
1250 
1251     op = object_property_add(obj, name, full_type,
1252                              object_get_link_property,
1253                              check ? object_set_link_property : NULL,
1254                              object_release_link_property,
1255                              prop,
1256                              &local_err);
1257     if (local_err) {
1258         error_propagate(errp, local_err);
1259         g_free(prop);
1260         goto out;
1261     }
1262 
1263     op->resolve = object_resolve_link_property;
1264 
1265 out:
1266     g_free(full_type);
1267 }
1268 
1269 gchar *object_get_canonical_path_component(Object *obj)
1270 {
1271     ObjectProperty *prop = NULL;
1272 
1273     g_assert(obj);
1274     g_assert(obj->parent != NULL);
1275 
1276     QTAILQ_FOREACH(prop, &obj->parent->properties, node) {
1277         if (!object_property_is_child(prop)) {
1278             continue;
1279         }
1280 
1281         if (prop->opaque == obj) {
1282             return g_strdup(prop->name);
1283         }
1284     }
1285 
1286     /* obj had a parent but was not a child, should never happen */
1287     g_assert_not_reached();
1288     return NULL;
1289 }
1290 
1291 gchar *object_get_canonical_path(Object *obj)
1292 {
1293     Object *root = object_get_root();
1294     char *newpath, *path = NULL;
1295 
1296     while (obj != root) {
1297         char *component = object_get_canonical_path_component(obj);
1298 
1299         if (path) {
1300             newpath = g_strdup_printf("%s/%s", component, path);
1301             g_free(component);
1302             g_free(path);
1303             path = newpath;
1304         } else {
1305             path = component;
1306         }
1307 
1308         obj = obj->parent;
1309     }
1310 
1311     newpath = g_strdup_printf("/%s", path ? path : "");
1312     g_free(path);
1313 
1314     return newpath;
1315 }
1316 
1317 Object *object_resolve_path_component(Object *parent, const gchar *part)
1318 {
1319     ObjectProperty *prop = object_property_find(parent, part, NULL);
1320     if (prop == NULL) {
1321         return NULL;
1322     }
1323 
1324     if (prop->resolve) {
1325         return prop->resolve(parent, prop->opaque, part);
1326     } else {
1327         return NULL;
1328     }
1329 }
1330 
1331 static Object *object_resolve_abs_path(Object *parent,
1332                                           gchar **parts,
1333                                           const char *typename,
1334                                           int index)
1335 {
1336     Object *child;
1337 
1338     if (parts[index] == NULL) {
1339         return object_dynamic_cast(parent, typename);
1340     }
1341 
1342     if (strcmp(parts[index], "") == 0) {
1343         return object_resolve_abs_path(parent, parts, typename, index + 1);
1344     }
1345 
1346     child = object_resolve_path_component(parent, parts[index]);
1347     if (!child) {
1348         return NULL;
1349     }
1350 
1351     return object_resolve_abs_path(child, parts, typename, index + 1);
1352 }
1353 
1354 static Object *object_resolve_partial_path(Object *parent,
1355                                               gchar **parts,
1356                                               const char *typename,
1357                                               bool *ambiguous)
1358 {
1359     Object *obj;
1360     ObjectProperty *prop;
1361 
1362     obj = object_resolve_abs_path(parent, parts, typename, 0);
1363 
1364     QTAILQ_FOREACH(prop, &parent->properties, node) {
1365         Object *found;
1366 
1367         if (!object_property_is_child(prop)) {
1368             continue;
1369         }
1370 
1371         found = object_resolve_partial_path(prop->opaque, parts,
1372                                             typename, ambiguous);
1373         if (found) {
1374             if (obj) {
1375                 if (ambiguous) {
1376                     *ambiguous = true;
1377                 }
1378                 return NULL;
1379             }
1380             obj = found;
1381         }
1382 
1383         if (ambiguous && *ambiguous) {
1384             return NULL;
1385         }
1386     }
1387 
1388     return obj;
1389 }
1390 
1391 Object *object_resolve_path_type(const char *path, const char *typename,
1392                                  bool *ambiguous)
1393 {
1394     Object *obj;
1395     gchar **parts;
1396 
1397     parts = g_strsplit(path, "/", 0);
1398     assert(parts);
1399 
1400     if (parts[0] == NULL || strcmp(parts[0], "") != 0) {
1401         if (ambiguous) {
1402             *ambiguous = false;
1403         }
1404         obj = object_resolve_partial_path(object_get_root(), parts,
1405                                           typename, ambiguous);
1406     } else {
1407         obj = object_resolve_abs_path(object_get_root(), parts, typename, 1);
1408     }
1409 
1410     g_strfreev(parts);
1411 
1412     return obj;
1413 }
1414 
1415 Object *object_resolve_path(const char *path, bool *ambiguous)
1416 {
1417     return object_resolve_path_type(path, TYPE_OBJECT, ambiguous);
1418 }
1419 
1420 typedef struct StringProperty
1421 {
1422     char *(*get)(Object *, Error **);
1423     void (*set)(Object *, const char *, Error **);
1424 } StringProperty;
1425 
1426 static void property_get_str(Object *obj, Visitor *v, void *opaque,
1427                              const char *name, Error **errp)
1428 {
1429     StringProperty *prop = opaque;
1430     char *value;
1431 
1432     value = prop->get(obj, errp);
1433     if (value) {
1434         visit_type_str(v, &value, name, errp);
1435         g_free(value);
1436     }
1437 }
1438 
1439 static void property_set_str(Object *obj, Visitor *v, void *opaque,
1440                              const char *name, Error **errp)
1441 {
1442     StringProperty *prop = opaque;
1443     char *value;
1444     Error *local_err = NULL;
1445 
1446     visit_type_str(v, &value, name, &local_err);
1447     if (local_err) {
1448         error_propagate(errp, local_err);
1449         return;
1450     }
1451 
1452     prop->set(obj, value, errp);
1453     g_free(value);
1454 }
1455 
1456 static void property_release_str(Object *obj, const char *name,
1457                                  void *opaque)
1458 {
1459     StringProperty *prop = opaque;
1460     g_free(prop);
1461 }
1462 
1463 void object_property_add_str(Object *obj, const char *name,
1464                            char *(*get)(Object *, Error **),
1465                            void (*set)(Object *, const char *, Error **),
1466                            Error **errp)
1467 {
1468     Error *local_err = NULL;
1469     StringProperty *prop = g_malloc0(sizeof(*prop));
1470 
1471     prop->get = get;
1472     prop->set = set;
1473 
1474     object_property_add(obj, name, "string",
1475                         get ? property_get_str : NULL,
1476                         set ? property_set_str : NULL,
1477                         property_release_str,
1478                         prop, &local_err);
1479     if (local_err) {
1480         error_propagate(errp, local_err);
1481         g_free(prop);
1482     }
1483 }
1484 
1485 typedef struct BoolProperty
1486 {
1487     bool (*get)(Object *, Error **);
1488     void (*set)(Object *, bool, Error **);
1489 } BoolProperty;
1490 
1491 static void property_get_bool(Object *obj, Visitor *v, void *opaque,
1492                               const char *name, Error **errp)
1493 {
1494     BoolProperty *prop = opaque;
1495     bool value;
1496 
1497     value = prop->get(obj, errp);
1498     visit_type_bool(v, &value, name, errp);
1499 }
1500 
1501 static void property_set_bool(Object *obj, Visitor *v, void *opaque,
1502                               const char *name, Error **errp)
1503 {
1504     BoolProperty *prop = opaque;
1505     bool value;
1506     Error *local_err = NULL;
1507 
1508     visit_type_bool(v, &value, name, &local_err);
1509     if (local_err) {
1510         error_propagate(errp, local_err);
1511         return;
1512     }
1513 
1514     prop->set(obj, value, errp);
1515 }
1516 
1517 static void property_release_bool(Object *obj, const char *name,
1518                                   void *opaque)
1519 {
1520     BoolProperty *prop = opaque;
1521     g_free(prop);
1522 }
1523 
1524 void object_property_add_bool(Object *obj, const char *name,
1525                               bool (*get)(Object *, Error **),
1526                               void (*set)(Object *, bool, Error **),
1527                               Error **errp)
1528 {
1529     Error *local_err = NULL;
1530     BoolProperty *prop = g_malloc0(sizeof(*prop));
1531 
1532     prop->get = get;
1533     prop->set = set;
1534 
1535     object_property_add(obj, name, "bool",
1536                         get ? property_get_bool : NULL,
1537                         set ? property_set_bool : NULL,
1538                         property_release_bool,
1539                         prop, &local_err);
1540     if (local_err) {
1541         error_propagate(errp, local_err);
1542         g_free(prop);
1543     }
1544 }
1545 
1546 typedef struct TMProperty {
1547     void (*get)(Object *, struct tm *, Error **);
1548 } TMProperty;
1549 
1550 static void property_get_tm(Object *obj, Visitor *v, void *opaque,
1551                             const char *name, Error **errp)
1552 {
1553     TMProperty *prop = opaque;
1554     Error *err = NULL;
1555     struct tm value;
1556 
1557     prop->get(obj, &value, &err);
1558     if (err) {
1559         goto out;
1560     }
1561 
1562     visit_start_struct(v, NULL, "struct tm", name, 0, &err);
1563     if (err) {
1564         goto out;
1565     }
1566     visit_type_int32(v, &value.tm_year, "tm_year", &err);
1567     if (err) {
1568         goto out_end;
1569     }
1570     visit_type_int32(v, &value.tm_mon, "tm_mon", &err);
1571     if (err) {
1572         goto out_end;
1573     }
1574     visit_type_int32(v, &value.tm_mday, "tm_mday", &err);
1575     if (err) {
1576         goto out_end;
1577     }
1578     visit_type_int32(v, &value.tm_hour, "tm_hour", &err);
1579     if (err) {
1580         goto out_end;
1581     }
1582     visit_type_int32(v, &value.tm_min, "tm_min", &err);
1583     if (err) {
1584         goto out_end;
1585     }
1586     visit_type_int32(v, &value.tm_sec, "tm_sec", &err);
1587     if (err) {
1588         goto out_end;
1589     }
1590 out_end:
1591     error_propagate(errp, err);
1592     err = NULL;
1593     visit_end_struct(v, errp);
1594 out:
1595     error_propagate(errp, err);
1596 
1597 }
1598 
1599 static void property_release_tm(Object *obj, const char *name,
1600                                 void *opaque)
1601 {
1602     TMProperty *prop = opaque;
1603     g_free(prop);
1604 }
1605 
1606 void object_property_add_tm(Object *obj, const char *name,
1607                             void (*get)(Object *, struct tm *, Error **),
1608                             Error **errp)
1609 {
1610     Error *local_err = NULL;
1611     TMProperty *prop = g_malloc0(sizeof(*prop));
1612 
1613     prop->get = get;
1614 
1615     object_property_add(obj, name, "struct tm",
1616                         get ? property_get_tm : NULL, NULL,
1617                         property_release_tm,
1618                         prop, &local_err);
1619     if (local_err) {
1620         error_propagate(errp, local_err);
1621         g_free(prop);
1622     }
1623 }
1624 
1625 static char *qdev_get_type(Object *obj, Error **errp)
1626 {
1627     return g_strdup(object_get_typename(obj));
1628 }
1629 
1630 static void property_get_uint8_ptr(Object *obj, Visitor *v,
1631                                    void *opaque, const char *name,
1632                                    Error **errp)
1633 {
1634     uint8_t value = *(uint8_t *)opaque;
1635     visit_type_uint8(v, &value, name, errp);
1636 }
1637 
1638 static void property_get_uint16_ptr(Object *obj, Visitor *v,
1639                                    void *opaque, const char *name,
1640                                    Error **errp)
1641 {
1642     uint16_t value = *(uint16_t *)opaque;
1643     visit_type_uint16(v, &value, name, errp);
1644 }
1645 
1646 static void property_get_uint32_ptr(Object *obj, Visitor *v,
1647                                    void *opaque, const char *name,
1648                                    Error **errp)
1649 {
1650     uint32_t value = *(uint32_t *)opaque;
1651     visit_type_uint32(v, &value, name, errp);
1652 }
1653 
1654 static void property_get_uint64_ptr(Object *obj, Visitor *v,
1655                                    void *opaque, const char *name,
1656                                    Error **errp)
1657 {
1658     uint64_t value = *(uint64_t *)opaque;
1659     visit_type_uint64(v, &value, name, errp);
1660 }
1661 
1662 void object_property_add_uint8_ptr(Object *obj, const char *name,
1663                                    const uint8_t *v, Error **errp)
1664 {
1665     object_property_add(obj, name, "uint8", property_get_uint8_ptr,
1666                         NULL, NULL, (void *)v, errp);
1667 }
1668 
1669 void object_property_add_uint16_ptr(Object *obj, const char *name,
1670                                     const uint16_t *v, Error **errp)
1671 {
1672     object_property_add(obj, name, "uint16", property_get_uint16_ptr,
1673                         NULL, NULL, (void *)v, errp);
1674 }
1675 
1676 void object_property_add_uint32_ptr(Object *obj, const char *name,
1677                                     const uint32_t *v, Error **errp)
1678 {
1679     object_property_add(obj, name, "uint32", property_get_uint32_ptr,
1680                         NULL, NULL, (void *)v, errp);
1681 }
1682 
1683 void object_property_add_uint64_ptr(Object *obj, const char *name,
1684                                     const uint64_t *v, Error **errp)
1685 {
1686     object_property_add(obj, name, "uint64", property_get_uint64_ptr,
1687                         NULL, NULL, (void *)v, errp);
1688 }
1689 
1690 typedef struct {
1691     Object *target_obj;
1692     const char *target_name;
1693 } AliasProperty;
1694 
1695 static void property_get_alias(Object *obj, struct Visitor *v, void *opaque,
1696                                const char *name, Error **errp)
1697 {
1698     AliasProperty *prop = opaque;
1699 
1700     object_property_get(prop->target_obj, v, prop->target_name, errp);
1701 }
1702 
1703 static void property_set_alias(Object *obj, struct Visitor *v, void *opaque,
1704                                const char *name, Error **errp)
1705 {
1706     AliasProperty *prop = opaque;
1707 
1708     object_property_set(prop->target_obj, v, prop->target_name, errp);
1709 }
1710 
1711 static Object *property_resolve_alias(Object *obj, void *opaque,
1712                                       const gchar *part)
1713 {
1714     AliasProperty *prop = opaque;
1715 
1716     return object_resolve_path_component(prop->target_obj, prop->target_name);
1717 }
1718 
1719 static void property_release_alias(Object *obj, const char *name, void *opaque)
1720 {
1721     AliasProperty *prop = opaque;
1722 
1723     g_free(prop);
1724 }
1725 
1726 void object_property_add_alias(Object *obj, const char *name,
1727                                Object *target_obj, const char *target_name,
1728                                Error **errp)
1729 {
1730     AliasProperty *prop;
1731     ObjectProperty *op;
1732     ObjectProperty *target_prop;
1733     gchar *prop_type;
1734     Error *local_err = NULL;
1735 
1736     target_prop = object_property_find(target_obj, target_name, errp);
1737     if (!target_prop) {
1738         return;
1739     }
1740 
1741     if (object_property_is_child(target_prop)) {
1742         prop_type = g_strdup_printf("link%s",
1743                                     target_prop->type + strlen("child"));
1744     } else {
1745         prop_type = g_strdup(target_prop->type);
1746     }
1747 
1748     prop = g_malloc(sizeof(*prop));
1749     prop->target_obj = target_obj;
1750     prop->target_name = target_name;
1751 
1752     op = object_property_add(obj, name, prop_type,
1753                              property_get_alias,
1754                              property_set_alias,
1755                              property_release_alias,
1756                              prop, &local_err);
1757     if (local_err) {
1758         error_propagate(errp, local_err);
1759         g_free(prop);
1760         goto out;
1761     }
1762     op->resolve = property_resolve_alias;
1763 
1764     object_property_set_description(obj, name,
1765                                     target_prop->description,
1766                                     &error_abort);
1767 
1768 out:
1769     g_free(prop_type);
1770 }
1771 
1772 void object_property_set_description(Object *obj, const char *name,
1773                                      const char *description, Error **errp)
1774 {
1775     ObjectProperty *op;
1776 
1777     op = object_property_find(obj, name, errp);
1778     if (!op) {
1779         return;
1780     }
1781 
1782     g_free(op->description);
1783     op->description = g_strdup(description);
1784 }
1785 
1786 static void object_instance_init(Object *obj)
1787 {
1788     object_property_add_str(obj, "type", qdev_get_type, NULL, NULL);
1789 }
1790 
1791 static void register_types(void)
1792 {
1793     static TypeInfo interface_info = {
1794         .name = TYPE_INTERFACE,
1795         .class_size = sizeof(InterfaceClass),
1796         .abstract = true,
1797     };
1798 
1799     static TypeInfo object_info = {
1800         .name = TYPE_OBJECT,
1801         .instance_size = sizeof(Object),
1802         .instance_init = object_instance_init,
1803         .abstract = true,
1804     };
1805 
1806     type_interface = type_register_internal(&interface_info);
1807     type_register_internal(&object_info);
1808 }
1809 
1810 type_init(register_types)
1811