xref: /qemu/qom/object.c (revision 1b3e6f88dc151578acb6158e22570cf3ee7cbb69)
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 "qapi/string-input-visitor.h"
17 #include "qapi/string-output-visitor.h"
18 
19 /* TODO: replace QObject with a simpler visitor to avoid a dependency
20  * of the QOM core on QObject?  */
21 #include "qemu/qom-qobject.h"
22 #include "qobject.h"
23 #include "qbool.h"
24 #include "qint.h"
25 #include "qstring.h"
26 
27 #define MAX_INTERFACES 32
28 
29 typedef struct InterfaceImpl InterfaceImpl;
30 typedef struct TypeImpl TypeImpl;
31 
32 struct InterfaceImpl
33 {
34     const char *typename;
35 };
36 
37 struct TypeImpl
38 {
39     const char *name;
40 
41     size_t class_size;
42 
43     size_t instance_size;
44 
45     void (*class_init)(ObjectClass *klass, void *data);
46     void (*class_base_init)(ObjectClass *klass, void *data);
47     void (*class_finalize)(ObjectClass *klass, void *data);
48 
49     void *class_data;
50 
51     void (*instance_init)(Object *obj);
52     void (*instance_finalize)(Object *obj);
53 
54     bool abstract;
55 
56     const char *parent;
57     TypeImpl *parent_type;
58 
59     ObjectClass *class;
60 
61     int num_interfaces;
62     InterfaceImpl interfaces[MAX_INTERFACES];
63 };
64 
65 static Type type_interface;
66 
67 static GHashTable *type_table_get(void)
68 {
69     static GHashTable *type_table;
70 
71     if (type_table == NULL) {
72         type_table = g_hash_table_new(g_str_hash, g_str_equal);
73     }
74 
75     return type_table;
76 }
77 
78 static void type_table_add(TypeImpl *ti)
79 {
80     g_hash_table_insert(type_table_get(), (void *)ti->name, ti);
81 }
82 
83 static TypeImpl *type_table_lookup(const char *name)
84 {
85     return g_hash_table_lookup(type_table_get(), name);
86 }
87 
88 static TypeImpl *type_register_internal(const TypeInfo *info)
89 {
90     TypeImpl *ti = g_malloc0(sizeof(*ti));
91     int i;
92 
93     g_assert(info->name != NULL);
94 
95     if (type_table_lookup(info->name) != NULL) {
96         fprintf(stderr, "Registering `%s' which already exists\n", info->name);
97         abort();
98     }
99 
100     ti->name = g_strdup(info->name);
101     ti->parent = g_strdup(info->parent);
102 
103     ti->class_size = info->class_size;
104     ti->instance_size = info->instance_size;
105 
106     ti->class_init = info->class_init;
107     ti->class_base_init = info->class_base_init;
108     ti->class_finalize = info->class_finalize;
109     ti->class_data = info->class_data;
110 
111     ti->instance_init = info->instance_init;
112     ti->instance_finalize = info->instance_finalize;
113 
114     ti->abstract = info->abstract;
115 
116     for (i = 0; info->interfaces && info->interfaces[i].type; i++) {
117         ti->interfaces[i].typename = g_strdup(info->interfaces[i].type);
118     }
119     ti->num_interfaces = i;
120 
121     type_table_add(ti);
122 
123     return ti;
124 }
125 
126 TypeImpl *type_register(const TypeInfo *info)
127 {
128     assert(info->parent);
129     return type_register_internal(info);
130 }
131 
132 TypeImpl *type_register_static(const TypeInfo *info)
133 {
134     return type_register(info);
135 }
136 
137 static TypeImpl *type_get_by_name(const char *name)
138 {
139     if (name == NULL) {
140         return NULL;
141     }
142 
143     return type_table_lookup(name);
144 }
145 
146 static TypeImpl *type_get_parent(TypeImpl *type)
147 {
148     if (!type->parent_type && type->parent) {
149         type->parent_type = type_get_by_name(type->parent);
150         g_assert(type->parent_type != NULL);
151     }
152 
153     return type->parent_type;
154 }
155 
156 static bool type_has_parent(TypeImpl *type)
157 {
158     return (type->parent != NULL);
159 }
160 
161 static size_t type_class_get_size(TypeImpl *ti)
162 {
163     if (ti->class_size) {
164         return ti->class_size;
165     }
166 
167     if (type_has_parent(ti)) {
168         return type_class_get_size(type_get_parent(ti));
169     }
170 
171     return sizeof(ObjectClass);
172 }
173 
174 static size_t type_object_get_size(TypeImpl *ti)
175 {
176     if (ti->instance_size) {
177         return ti->instance_size;
178     }
179 
180     if (type_has_parent(ti)) {
181         return type_object_get_size(type_get_parent(ti));
182     }
183 
184     return 0;
185 }
186 
187 static bool type_is_ancestor(TypeImpl *type, TypeImpl *target_type)
188 {
189     assert(target_type);
190 
191     /* Check if typename is a direct ancestor of type */
192     while (type) {
193         if (type == target_type) {
194             return true;
195         }
196 
197         type = type_get_parent(type);
198     }
199 
200     return false;
201 }
202 
203 static void type_initialize(TypeImpl *ti);
204 
205 static void type_initialize_interface(TypeImpl *ti, const char *parent)
206 {
207     InterfaceClass *new_iface;
208     TypeInfo info = { };
209     TypeImpl *iface_impl;
210 
211     info.parent = parent;
212     info.name = g_strdup_printf("%s::%s", ti->name, info.parent);
213     info.abstract = true;
214 
215     iface_impl = type_register(&info);
216     type_initialize(iface_impl);
217     g_free((char *)info.name);
218 
219     new_iface = (InterfaceClass *)iface_impl->class;
220     new_iface->concrete_class = ti->class;
221 
222     ti->class->interfaces = g_slist_append(ti->class->interfaces,
223                                            iface_impl->class);
224 }
225 
226 static void type_initialize(TypeImpl *ti)
227 {
228     TypeImpl *parent;
229 
230     if (ti->class) {
231         return;
232     }
233 
234     ti->class_size = type_class_get_size(ti);
235     ti->instance_size = type_object_get_size(ti);
236 
237     ti->class = g_malloc0(ti->class_size);
238 
239     parent = type_get_parent(ti);
240     if (parent) {
241         type_initialize(parent);
242         GSList *e;
243         int i;
244 
245         g_assert(parent->class_size <= ti->class_size);
246         memcpy(ti->class, parent->class, parent->class_size);
247 
248         for (e = parent->class->interfaces; e; e = e->next) {
249             ObjectClass *iface = e->data;
250             type_initialize_interface(ti, object_class_get_name(iface));
251         }
252 
253         for (i = 0; i < ti->num_interfaces; i++) {
254             TypeImpl *t = type_get_by_name(ti->interfaces[i].typename);
255             for (e = ti->class->interfaces; e; e = e->next) {
256                 TypeImpl *target_type = OBJECT_CLASS(e->data)->type;
257 
258                 if (type_is_ancestor(target_type, t)) {
259                     break;
260                 }
261             }
262 
263             if (e) {
264                 continue;
265             }
266 
267             type_initialize_interface(ti, ti->interfaces[i].typename);
268         }
269     }
270 
271     ti->class->type = ti;
272 
273     while (parent) {
274         if (parent->class_base_init) {
275             parent->class_base_init(ti->class, ti->class_data);
276         }
277         parent = type_get_parent(parent);
278     }
279 
280     if (ti->class_init) {
281         ti->class_init(ti->class, ti->class_data);
282     }
283 
284 
285 }
286 
287 static void object_init_with_type(Object *obj, TypeImpl *ti)
288 {
289     if (type_has_parent(ti)) {
290         object_init_with_type(obj, type_get_parent(ti));
291     }
292 
293     if (ti->instance_init) {
294         ti->instance_init(obj);
295     }
296 }
297 
298 void object_initialize_with_type(void *data, TypeImpl *type)
299 {
300     Object *obj = data;
301 
302     g_assert(type != NULL);
303     type_initialize(type);
304 
305     g_assert(type->instance_size >= sizeof(Object));
306     g_assert(type->abstract == false);
307 
308     memset(obj, 0, type->instance_size);
309     obj->class = type->class;
310     QTAILQ_INIT(&obj->properties);
311     object_init_with_type(obj, type);
312 }
313 
314 void object_initialize(void *data, const char *typename)
315 {
316     TypeImpl *type = type_get_by_name(typename);
317 
318     object_initialize_with_type(data, type);
319 }
320 
321 static inline bool object_property_is_child(ObjectProperty *prop)
322 {
323     return strstart(prop->type, "child<", NULL);
324 }
325 
326 static inline bool object_property_is_link(ObjectProperty *prop)
327 {
328     return strstart(prop->type, "link<", NULL);
329 }
330 
331 static void object_property_del_all(Object *obj)
332 {
333     while (!QTAILQ_EMPTY(&obj->properties)) {
334         ObjectProperty *prop = QTAILQ_FIRST(&obj->properties);
335 
336         QTAILQ_REMOVE(&obj->properties, prop, node);
337 
338         if (prop->release) {
339             prop->release(obj, prop->name, prop->opaque);
340         }
341 
342         g_free(prop->name);
343         g_free(prop->type);
344         g_free(prop);
345     }
346 }
347 
348 static void object_property_del_child(Object *obj, Object *child, Error **errp)
349 {
350     ObjectProperty *prop;
351 
352     QTAILQ_FOREACH(prop, &obj->properties, node) {
353         if (object_property_is_child(prop) && prop->opaque == child) {
354             object_property_del(obj, prop->name, errp);
355             break;
356         }
357     }
358 }
359 
360 void object_unparent(Object *obj)
361 {
362     if (obj->parent) {
363         object_property_del_child(obj->parent, obj, NULL);
364     }
365 }
366 
367 static void object_deinit(Object *obj, TypeImpl *type)
368 {
369     if (type->instance_finalize) {
370         type->instance_finalize(obj);
371     }
372 
373     if (type_has_parent(type)) {
374         object_deinit(obj, type_get_parent(type));
375     }
376 }
377 
378 void object_finalize(void *data)
379 {
380     Object *obj = data;
381     TypeImpl *ti = obj->class->type;
382 
383     object_deinit(obj, ti);
384     object_property_del_all(obj);
385 
386     g_assert(obj->ref == 0);
387 }
388 
389 Object *object_new_with_type(Type type)
390 {
391     Object *obj;
392 
393     g_assert(type != NULL);
394     type_initialize(type);
395 
396     obj = g_malloc(type->instance_size);
397     object_initialize_with_type(obj, type);
398     object_ref(obj);
399 
400     return obj;
401 }
402 
403 Object *object_new(const char *typename)
404 {
405     TypeImpl *ti = type_get_by_name(typename);
406 
407     return object_new_with_type(ti);
408 }
409 
410 void object_delete(Object *obj)
411 {
412     object_unparent(obj);
413     g_assert(obj->ref == 1);
414     object_unref(obj);
415     g_free(obj);
416 }
417 
418 Object *object_dynamic_cast(Object *obj, const char *typename)
419 {
420     if (object_class_dynamic_cast(object_get_class(obj), typename)) {
421         return obj;
422     }
423 
424     return NULL;
425 }
426 
427 Object *object_dynamic_cast_assert(Object *obj, const char *typename)
428 {
429     Object *inst;
430 
431     inst = object_dynamic_cast(obj, typename);
432 
433     if (!inst) {
434         fprintf(stderr, "Object %p is not an instance of type %s\n",
435                 obj, typename);
436         abort();
437     }
438 
439     return inst;
440 }
441 
442 ObjectClass *object_class_dynamic_cast(ObjectClass *class,
443                                        const char *typename)
444 {
445     TypeImpl *target_type = type_get_by_name(typename);
446     TypeImpl *type = class->type;
447     ObjectClass *ret = NULL;
448 
449     if (type->num_interfaces && type_is_ancestor(target_type, type_interface)) {
450         int found = 0;
451         GSList *i;
452 
453         for (i = class->interfaces; i; i = i->next) {
454             ObjectClass *target_class = i->data;
455 
456             if (type_is_ancestor(target_class->type, target_type)) {
457                 ret = target_class;
458                 found++;
459             }
460          }
461 
462         /* The match was ambiguous, don't allow a cast */
463         if (found > 1) {
464             ret = NULL;
465         }
466     } else if (type_is_ancestor(type, target_type)) {
467         ret = class;
468     }
469 
470     return ret;
471 }
472 
473 ObjectClass *object_class_dynamic_cast_assert(ObjectClass *class,
474                                               const char *typename)
475 {
476     ObjectClass *ret = object_class_dynamic_cast(class, typename);
477 
478     if (!ret) {
479         fprintf(stderr, "Object %p is not an instance of type %s\n",
480                 class, typename);
481         abort();
482     }
483 
484     return ret;
485 }
486 
487 const char *object_get_typename(Object *obj)
488 {
489     return obj->class->type->name;
490 }
491 
492 ObjectClass *object_get_class(Object *obj)
493 {
494     return obj->class;
495 }
496 
497 const char *object_class_get_name(ObjectClass *klass)
498 {
499     return klass->type->name;
500 }
501 
502 ObjectClass *object_class_by_name(const char *typename)
503 {
504     TypeImpl *type = type_get_by_name(typename);
505 
506     if (!type) {
507         return NULL;
508     }
509 
510     type_initialize(type);
511 
512     return type->class;
513 }
514 
515 ObjectClass *object_class_get_parent(ObjectClass *class)
516 {
517     TypeImpl *type = type_get_parent(class->type);
518 
519     if (!type) {
520         return NULL;
521     }
522 
523     type_initialize(type);
524 
525     return type->class;
526 }
527 
528 typedef struct OCFData
529 {
530     void (*fn)(ObjectClass *klass, void *opaque);
531     const char *implements_type;
532     bool include_abstract;
533     void *opaque;
534 } OCFData;
535 
536 static void object_class_foreach_tramp(gpointer key, gpointer value,
537                                        gpointer opaque)
538 {
539     OCFData *data = opaque;
540     TypeImpl *type = value;
541     ObjectClass *k;
542 
543     type_initialize(type);
544     k = type->class;
545 
546     if (!data->include_abstract && type->abstract) {
547         return;
548     }
549 
550     if (data->implements_type &&
551         !object_class_dynamic_cast(k, data->implements_type)) {
552         return;
553     }
554 
555     data->fn(k, data->opaque);
556 }
557 
558 void object_class_foreach(void (*fn)(ObjectClass *klass, void *opaque),
559                           const char *implements_type, bool include_abstract,
560                           void *opaque)
561 {
562     OCFData data = { fn, implements_type, include_abstract, opaque };
563 
564     g_hash_table_foreach(type_table_get(), object_class_foreach_tramp, &data);
565 }
566 
567 int object_child_foreach(Object *obj, int (*fn)(Object *child, void *opaque),
568                          void *opaque)
569 {
570     ObjectProperty *prop;
571     int ret = 0;
572 
573     QTAILQ_FOREACH(prop, &obj->properties, node) {
574         if (object_property_is_child(prop)) {
575             ret = fn(prop->opaque, opaque);
576             if (ret != 0) {
577                 break;
578             }
579         }
580     }
581     return ret;
582 }
583 
584 static void object_class_get_list_tramp(ObjectClass *klass, void *opaque)
585 {
586     GSList **list = opaque;
587 
588     *list = g_slist_prepend(*list, klass);
589 }
590 
591 GSList *object_class_get_list(const char *implements_type,
592                               bool include_abstract)
593 {
594     GSList *list = NULL;
595 
596     object_class_foreach(object_class_get_list_tramp,
597                          implements_type, include_abstract, &list);
598     return list;
599 }
600 
601 void object_ref(Object *obj)
602 {
603     obj->ref++;
604 }
605 
606 void object_unref(Object *obj)
607 {
608     g_assert(obj->ref > 0);
609     obj->ref--;
610 
611     /* parent always holds a reference to its children */
612     if (obj->ref == 0) {
613         object_finalize(obj);
614     }
615 }
616 
617 void object_property_add(Object *obj, const char *name, const char *type,
618                          ObjectPropertyAccessor *get,
619                          ObjectPropertyAccessor *set,
620                          ObjectPropertyRelease *release,
621                          void *opaque, Error **errp)
622 {
623     ObjectProperty *prop = g_malloc0(sizeof(*prop));
624 
625     prop->name = g_strdup(name);
626     prop->type = g_strdup(type);
627 
628     prop->get = get;
629     prop->set = set;
630     prop->release = release;
631     prop->opaque = opaque;
632 
633     QTAILQ_INSERT_TAIL(&obj->properties, prop, node);
634 }
635 
636 ObjectProperty *object_property_find(Object *obj, const char *name,
637                                      Error **errp)
638 {
639     ObjectProperty *prop;
640 
641     QTAILQ_FOREACH(prop, &obj->properties, node) {
642         if (strcmp(prop->name, name) == 0) {
643             return prop;
644         }
645     }
646 
647     error_set(errp, QERR_PROPERTY_NOT_FOUND, "", name);
648     return NULL;
649 }
650 
651 void object_property_del(Object *obj, const char *name, Error **errp)
652 {
653     ObjectProperty *prop = object_property_find(obj, name, errp);
654     if (prop == NULL) {
655         return;
656     }
657 
658     if (prop->release) {
659         prop->release(obj, name, prop->opaque);
660     }
661 
662     QTAILQ_REMOVE(&obj->properties, prop, node);
663 
664     g_free(prop->name);
665     g_free(prop->type);
666     g_free(prop);
667 }
668 
669 void object_property_get(Object *obj, Visitor *v, const char *name,
670                          Error **errp)
671 {
672     ObjectProperty *prop = object_property_find(obj, name, errp);
673     if (prop == NULL) {
674         return;
675     }
676 
677     if (!prop->get) {
678         error_set(errp, QERR_PERMISSION_DENIED);
679     } else {
680         prop->get(obj, v, prop->opaque, name, errp);
681     }
682 }
683 
684 void object_property_set(Object *obj, Visitor *v, const char *name,
685                          Error **errp)
686 {
687     ObjectProperty *prop = object_property_find(obj, name, errp);
688     if (prop == NULL) {
689         return;
690     }
691 
692     if (!prop->set) {
693         error_set(errp, QERR_PERMISSION_DENIED);
694     } else {
695         prop->set(obj, v, prop->opaque, name, errp);
696     }
697 }
698 
699 void object_property_set_str(Object *obj, const char *value,
700                              const char *name, Error **errp)
701 {
702     QString *qstr = qstring_from_str(value);
703     object_property_set_qobject(obj, QOBJECT(qstr), name, errp);
704 
705     QDECREF(qstr);
706 }
707 
708 char *object_property_get_str(Object *obj, const char *name,
709                               Error **errp)
710 {
711     QObject *ret = object_property_get_qobject(obj, name, errp);
712     QString *qstring;
713     char *retval;
714 
715     if (!ret) {
716         return NULL;
717     }
718     qstring = qobject_to_qstring(ret);
719     if (!qstring) {
720         error_set(errp, QERR_INVALID_PARAMETER_TYPE, name, "string");
721         retval = NULL;
722     } else {
723         retval = g_strdup(qstring_get_str(qstring));
724     }
725 
726     QDECREF(qstring);
727     return retval;
728 }
729 
730 void object_property_set_link(Object *obj, Object *value,
731                               const char *name, Error **errp)
732 {
733     object_property_set_str(obj, object_get_canonical_path(value),
734                             name, errp);
735 }
736 
737 Object *object_property_get_link(Object *obj, const char *name,
738                                  Error **errp)
739 {
740     char *str = object_property_get_str(obj, name, errp);
741     Object *target = NULL;
742 
743     if (str && *str) {
744         target = object_resolve_path(str, NULL);
745         if (!target) {
746             error_set(errp, QERR_DEVICE_NOT_FOUND, str);
747         }
748     }
749 
750     g_free(str);
751     return target;
752 }
753 
754 void object_property_set_bool(Object *obj, bool value,
755                               const char *name, Error **errp)
756 {
757     QBool *qbool = qbool_from_int(value);
758     object_property_set_qobject(obj, QOBJECT(qbool), name, errp);
759 
760     QDECREF(qbool);
761 }
762 
763 bool object_property_get_bool(Object *obj, const char *name,
764                               Error **errp)
765 {
766     QObject *ret = object_property_get_qobject(obj, name, errp);
767     QBool *qbool;
768     bool retval;
769 
770     if (!ret) {
771         return false;
772     }
773     qbool = qobject_to_qbool(ret);
774     if (!qbool) {
775         error_set(errp, QERR_INVALID_PARAMETER_TYPE, name, "boolean");
776         retval = false;
777     } else {
778         retval = qbool_get_int(qbool);
779     }
780 
781     QDECREF(qbool);
782     return retval;
783 }
784 
785 void object_property_set_int(Object *obj, int64_t value,
786                              const char *name, Error **errp)
787 {
788     QInt *qint = qint_from_int(value);
789     object_property_set_qobject(obj, QOBJECT(qint), name, errp);
790 
791     QDECREF(qint);
792 }
793 
794 int64_t object_property_get_int(Object *obj, const char *name,
795                                 Error **errp)
796 {
797     QObject *ret = object_property_get_qobject(obj, name, errp);
798     QInt *qint;
799     int64_t retval;
800 
801     if (!ret) {
802         return -1;
803     }
804     qint = qobject_to_qint(ret);
805     if (!qint) {
806         error_set(errp, QERR_INVALID_PARAMETER_TYPE, name, "int");
807         retval = -1;
808     } else {
809         retval = qint_get_int(qint);
810     }
811 
812     QDECREF(qint);
813     return retval;
814 }
815 
816 void object_property_parse(Object *obj, const char *string,
817                            const char *name, Error **errp)
818 {
819     StringInputVisitor *mi;
820     mi = string_input_visitor_new(string);
821     object_property_set(obj, string_input_get_visitor(mi), name, errp);
822 
823     string_input_visitor_cleanup(mi);
824 }
825 
826 char *object_property_print(Object *obj, const char *name,
827                             Error **errp)
828 {
829     StringOutputVisitor *mo;
830     char *string;
831 
832     mo = string_output_visitor_new();
833     object_property_get(obj, string_output_get_visitor(mo), name, errp);
834     string = string_output_get_string(mo);
835     string_output_visitor_cleanup(mo);
836     return string;
837 }
838 
839 const char *object_property_get_type(Object *obj, const char *name, Error **errp)
840 {
841     ObjectProperty *prop = object_property_find(obj, name, errp);
842     if (prop == NULL) {
843         return NULL;
844     }
845 
846     return prop->type;
847 }
848 
849 Object *object_get_root(void)
850 {
851     static Object *root;
852 
853     if (!root) {
854         root = object_new("container");
855     }
856 
857     return root;
858 }
859 
860 static void object_get_child_property(Object *obj, Visitor *v, void *opaque,
861                                       const char *name, Error **errp)
862 {
863     Object *child = opaque;
864     gchar *path;
865 
866     path = object_get_canonical_path(child);
867     visit_type_str(v, &path, name, errp);
868     g_free(path);
869 }
870 
871 static void object_finalize_child_property(Object *obj, const char *name,
872                                            void *opaque)
873 {
874     Object *child = opaque;
875 
876     object_unref(child);
877 }
878 
879 void object_property_add_child(Object *obj, const char *name,
880                                Object *child, Error **errp)
881 {
882     gchar *type;
883 
884     type = g_strdup_printf("child<%s>", object_get_typename(OBJECT(child)));
885 
886     object_property_add(obj, name, type, object_get_child_property,
887                         NULL, object_finalize_child_property, child, errp);
888 
889     object_ref(child);
890     g_assert(child->parent == NULL);
891     child->parent = obj;
892 
893     g_free(type);
894 }
895 
896 static void object_get_link_property(Object *obj, Visitor *v, void *opaque,
897                                      const char *name, Error **errp)
898 {
899     Object **child = opaque;
900     gchar *path;
901 
902     if (*child) {
903         path = object_get_canonical_path(*child);
904         visit_type_str(v, &path, name, errp);
905         g_free(path);
906     } else {
907         path = (gchar *)"";
908         visit_type_str(v, &path, name, errp);
909     }
910 }
911 
912 static void object_set_link_property(Object *obj, Visitor *v, void *opaque,
913                                      const char *name, Error **errp)
914 {
915     Object **child = opaque;
916     Object *old_target;
917     bool ambiguous = false;
918     const char *type;
919     char *path;
920     gchar *target_type;
921 
922     type = object_property_get_type(obj, name, NULL);
923 
924     visit_type_str(v, &path, name, errp);
925 
926     old_target = *child;
927     *child = NULL;
928 
929     if (strcmp(path, "") != 0) {
930         Object *target;
931 
932         /* Go from link<FOO> to FOO.  */
933         target_type = g_strndup(&type[5], strlen(type) - 6);
934         target = object_resolve_path_type(path, target_type, &ambiguous);
935 
936         if (ambiguous) {
937             error_set(errp, QERR_AMBIGUOUS_PATH, path);
938         } else if (target) {
939             object_ref(target);
940             *child = target;
941         } else {
942             target = object_resolve_path(path, &ambiguous);
943             if (target || ambiguous) {
944                 error_set(errp, QERR_INVALID_PARAMETER_TYPE, name, target_type);
945             } else {
946                 error_set(errp, QERR_DEVICE_NOT_FOUND, path);
947             }
948         }
949         g_free(target_type);
950     }
951 
952     g_free(path);
953 
954     if (old_target != NULL) {
955         object_unref(old_target);
956     }
957 }
958 
959 void object_property_add_link(Object *obj, const char *name,
960                               const char *type, Object **child,
961                               Error **errp)
962 {
963     gchar *full_type;
964 
965     full_type = g_strdup_printf("link<%s>", type);
966 
967     object_property_add(obj, name, full_type,
968                         object_get_link_property,
969                         object_set_link_property,
970                         NULL, child, errp);
971 
972     g_free(full_type);
973 }
974 
975 gchar *object_get_canonical_path(Object *obj)
976 {
977     Object *root = object_get_root();
978     char *newpath = NULL, *path = NULL;
979 
980     while (obj != root) {
981         ObjectProperty *prop = NULL;
982 
983         g_assert(obj->parent != NULL);
984 
985         QTAILQ_FOREACH(prop, &obj->parent->properties, node) {
986             if (!object_property_is_child(prop)) {
987                 continue;
988             }
989 
990             if (prop->opaque == obj) {
991                 if (path) {
992                     newpath = g_strdup_printf("%s/%s", prop->name, path);
993                     g_free(path);
994                     path = newpath;
995                 } else {
996                     path = g_strdup(prop->name);
997                 }
998                 break;
999             }
1000         }
1001 
1002         g_assert(prop != NULL);
1003 
1004         obj = obj->parent;
1005     }
1006 
1007     newpath = g_strdup_printf("/%s", path);
1008     g_free(path);
1009 
1010     return newpath;
1011 }
1012 
1013 Object *object_resolve_path_component(Object *parent, gchar *part)
1014 {
1015     ObjectProperty *prop = object_property_find(parent, part, NULL);
1016     if (prop == NULL) {
1017         return NULL;
1018     }
1019 
1020     if (object_property_is_link(prop)) {
1021         return *(Object **)prop->opaque;
1022     } else if (object_property_is_child(prop)) {
1023         return prop->opaque;
1024     } else {
1025         return NULL;
1026     }
1027 }
1028 
1029 static Object *object_resolve_abs_path(Object *parent,
1030                                           gchar **parts,
1031                                           const char *typename,
1032                                           int index)
1033 {
1034     Object *child;
1035 
1036     if (parts[index] == NULL) {
1037         return object_dynamic_cast(parent, typename);
1038     }
1039 
1040     if (strcmp(parts[index], "") == 0) {
1041         return object_resolve_abs_path(parent, parts, typename, index + 1);
1042     }
1043 
1044     child = object_resolve_path_component(parent, parts[index]);
1045     if (!child) {
1046         return NULL;
1047     }
1048 
1049     return object_resolve_abs_path(child, parts, typename, index + 1);
1050 }
1051 
1052 static Object *object_resolve_partial_path(Object *parent,
1053                                               gchar **parts,
1054                                               const char *typename,
1055                                               bool *ambiguous)
1056 {
1057     Object *obj;
1058     ObjectProperty *prop;
1059 
1060     obj = object_resolve_abs_path(parent, parts, typename, 0);
1061 
1062     QTAILQ_FOREACH(prop, &parent->properties, node) {
1063         Object *found;
1064 
1065         if (!object_property_is_child(prop)) {
1066             continue;
1067         }
1068 
1069         found = object_resolve_partial_path(prop->opaque, parts,
1070                                             typename, ambiguous);
1071         if (found) {
1072             if (obj) {
1073                 if (ambiguous) {
1074                     *ambiguous = true;
1075                 }
1076                 return NULL;
1077             }
1078             obj = found;
1079         }
1080 
1081         if (ambiguous && *ambiguous) {
1082             return NULL;
1083         }
1084     }
1085 
1086     return obj;
1087 }
1088 
1089 Object *object_resolve_path_type(const char *path, const char *typename,
1090                                  bool *ambiguous)
1091 {
1092     bool partial_path = true;
1093     Object *obj;
1094     gchar **parts;
1095 
1096     parts = g_strsplit(path, "/", 0);
1097     if (parts == NULL || parts[0] == NULL) {
1098         g_strfreev(parts);
1099         return object_get_root();
1100     }
1101 
1102     if (strcmp(parts[0], "") == 0) {
1103         partial_path = false;
1104     }
1105 
1106     if (partial_path) {
1107         if (ambiguous) {
1108             *ambiguous = false;
1109         }
1110         obj = object_resolve_partial_path(object_get_root(), parts,
1111                                           typename, ambiguous);
1112     } else {
1113         obj = object_resolve_abs_path(object_get_root(), parts, typename, 1);
1114     }
1115 
1116     g_strfreev(parts);
1117 
1118     return obj;
1119 }
1120 
1121 Object *object_resolve_path(const char *path, bool *ambiguous)
1122 {
1123     return object_resolve_path_type(path, TYPE_OBJECT, ambiguous);
1124 }
1125 
1126 typedef struct StringProperty
1127 {
1128     char *(*get)(Object *, Error **);
1129     void (*set)(Object *, const char *, Error **);
1130 } StringProperty;
1131 
1132 static void property_get_str(Object *obj, Visitor *v, void *opaque,
1133                              const char *name, Error **errp)
1134 {
1135     StringProperty *prop = opaque;
1136     char *value;
1137 
1138     value = prop->get(obj, errp);
1139     if (value) {
1140         visit_type_str(v, &value, name, errp);
1141         g_free(value);
1142     }
1143 }
1144 
1145 static void property_set_str(Object *obj, Visitor *v, void *opaque,
1146                              const char *name, Error **errp)
1147 {
1148     StringProperty *prop = opaque;
1149     char *value;
1150     Error *local_err = NULL;
1151 
1152     visit_type_str(v, &value, name, &local_err);
1153     if (local_err) {
1154         error_propagate(errp, local_err);
1155         return;
1156     }
1157 
1158     prop->set(obj, value, errp);
1159     g_free(value);
1160 }
1161 
1162 static void property_release_str(Object *obj, const char *name,
1163                                  void *opaque)
1164 {
1165     StringProperty *prop = opaque;
1166     g_free(prop);
1167 }
1168 
1169 void object_property_add_str(Object *obj, const char *name,
1170                            char *(*get)(Object *, Error **),
1171                            void (*set)(Object *, const char *, Error **),
1172                            Error **errp)
1173 {
1174     StringProperty *prop = g_malloc0(sizeof(*prop));
1175 
1176     prop->get = get;
1177     prop->set = set;
1178 
1179     object_property_add(obj, name, "string",
1180                         get ? property_get_str : NULL,
1181                         set ? property_set_str : NULL,
1182                         property_release_str,
1183                         prop, errp);
1184 }
1185 
1186 static char *qdev_get_type(Object *obj, Error **errp)
1187 {
1188     return g_strdup(object_get_typename(obj));
1189 }
1190 
1191 static void object_instance_init(Object *obj)
1192 {
1193     object_property_add_str(obj, "type", qdev_get_type, NULL, NULL);
1194 }
1195 
1196 static void register_types(void)
1197 {
1198     static TypeInfo interface_info = {
1199         .name = TYPE_INTERFACE,
1200         .class_size = sizeof(InterfaceClass),
1201         .abstract = true,
1202     };
1203 
1204     static TypeInfo object_info = {
1205         .name = TYPE_OBJECT,
1206         .instance_size = sizeof(Object),
1207         .instance_init = object_instance_init,
1208         .abstract = true,
1209     };
1210 
1211     type_interface = type_register_internal(&interface_info);
1212     type_register_internal(&object_info);
1213 }
1214 
1215 type_init(register_types)
1216