Archipelago » qemu

/*

 * QEMU Object Model

 *

 * Copyright IBM, Corp. 2011

 *

 * Authors:

 *  Anthony Liguori   <aliguori@us.ibm.com>

 *

 * This work is licensed under the terms of the GNU GPL, version 2 or later.

 * See the COPYING file in the top-level directory.

 */

#include "qom/object.h"

#include "qemu-common.h"

#include "qapi/visitor.h"

#include "qapi/string-input-visitor.h"

#include "qapi/string-output-visitor.h"

#include "qapi/qmp/qerror.h"

#include "trace.h"

/* TODO: replace QObject with a simpler visitor to avoid a dependency

 * of the QOM core on QObject?  */

#include "qom/qom-qobject.h"

#include "qapi/qmp/qobject.h"

#include "qapi/qmp/qbool.h"

#include "qapi/qmp/qint.h"

#include "qapi/qmp/qstring.h"

#define MAX_INTERFACES 32

typedef struct InterfaceImpl InterfaceImpl;

typedef struct TypeImpl TypeImpl;

struct InterfaceImpl

{

    const char *typename;

};

struct TypeImpl

{

    const char *name;

    size_t class_size;

    size_t instance_size;

    void (*class_init)(ObjectClass *klass, void *data);

    void (*class_base_init)(ObjectClass *klass, void *data);

    void (*class_finalize)(ObjectClass *klass, void *data);

    void *class_data;

    void (*instance_init)(Object *obj);

    void (*instance_post_init)(Object *obj);

    void (*instance_finalize)(Object *obj);

    bool abstract;

    const char *parent;

    TypeImpl *parent_type;

    ObjectClass *class;

    int num_interfaces;

    InterfaceImpl interfaces[MAX_INTERFACES];

};

static Type type_interface;

static GHashTable *type_table_get(void)

{

    static GHashTable *type_table;

    if (type_table == NULL) {

        type_table = g_hash_table_new(g_str_hash, g_str_equal);

    }

    return type_table;

}

static bool enumerating_types;

static void type_table_add(TypeImpl *ti)

{

    assert(!enumerating_types);

    g_hash_table_insert(type_table_get(), (void *)ti->name, ti);

}

static TypeImpl *type_table_lookup(const char *name)

{

    return g_hash_table_lookup(type_table_get(), name);

}

static TypeImpl *type_new(const TypeInfo *info)

{

    TypeImpl *ti = g_malloc0(sizeof(*ti));

    int i;

    g_assert(info->name != NULL);

    if (type_table_lookup(info->name) != NULL) {

        fprintf(stderr, "Registering `%s' which already exists\n", info->name);

        abort();

    }

    ti->name = g_strdup(info->name);

    ti->parent = g_strdup(info->parent);

    ti->class_size = info->class_size;

    ti->instance_size = info->instance_size;

    ti->class_init = info->class_init;

    ti->class_base_init = info->class_base_init;

    ti->class_finalize = info->class_finalize;

    ti->class_data = info->class_data;

    ti->instance_init = info->instance_init;

    ti->instance_post_init = info->instance_post_init;

    ti->instance_finalize = info->instance_finalize;

    ti->abstract = info->abstract;

    for (i = 0; info->interfaces && info->interfaces[i].type; i++) {

        ti->interfaces[i].typename = g_strdup(info->interfaces[i].type);

    }

    ti->num_interfaces = i;

    return ti;

}

static TypeImpl *type_register_internal(const TypeInfo *info)

{

    TypeImpl *ti;

    ti = type_new(info);

    type_table_add(ti);

    return ti;

}

TypeImpl *type_register(const TypeInfo *info)

{

    assert(info->parent);

    return type_register_internal(info);

}

TypeImpl *type_register_static(const TypeInfo *info)

{

    return type_register(info);

}

static TypeImpl *type_get_by_name(const char *name)

{

    if (name == NULL) {

        return NULL;

    }

    return type_table_lookup(name);

}

static TypeImpl *type_get_parent(TypeImpl *type)

{

    if (!type->parent_type && type->parent) {

        type->parent_type = type_get_by_name(type->parent);

        g_assert(type->parent_type != NULL);

    }

    return type->parent_type;

}

static bool type_has_parent(TypeImpl *type)

{

    return (type->parent != NULL);

}

static size_t type_class_get_size(TypeImpl *ti)

{

    if (ti->class_size) {

        return ti->class_size;

    }

    if (type_has_parent(ti)) {

        return type_class_get_size(type_get_parent(ti));

    }

    return sizeof(ObjectClass);

}

static size_t type_object_get_size(TypeImpl *ti)

{

    if (ti->instance_size) {

        return ti->instance_size;

    }

    if (type_has_parent(ti)) {

        return type_object_get_size(type_get_parent(ti));

    }

    return 0;

}

static bool type_is_ancestor(TypeImpl *type, TypeImpl *target_type)

{

    assert(target_type);

    /* Check if typename is a direct ancestor of type */

    while (type) {

        if (type == target_type) {

            return true;

        }

        type = type_get_parent(type);

    }

    return false;

}

static void type_initialize(TypeImpl *ti);

static void type_initialize_interface(TypeImpl *ti, TypeImpl *interface_type,

                                      TypeImpl *parent_type)

{

    InterfaceClass *new_iface;

    TypeInfo info = { };

    TypeImpl *iface_impl;

    info.parent = parent_type->name;

    info.name = g_strdup_printf("%s::%s", ti->name, interface_type->name);

    info.abstract = true;

    iface_impl = type_new(&info);

    iface_impl->parent_type = parent_type;

    type_initialize(iface_impl);

    g_free((char *)info.name);

    new_iface = (InterfaceClass *)iface_impl->class;

    new_iface->concrete_class = ti->class;

    new_iface->interface_type = interface_type;

    ti->class->interfaces = g_slist_append(ti->class->interfaces,

                                           iface_impl->class);

}

static void type_initialize(TypeImpl *ti)

{

    TypeImpl *parent;

    if (ti->class) {

        return;

    }

    ti->class_size = type_class_get_size(ti);

    ti->instance_size = type_object_get_size(ti);

    ti->class = g_malloc0(ti->class_size);

    parent = type_get_parent(ti);

    if (parent) {

        type_initialize(parent);

        GSList *e;

        int i;

        g_assert(parent->class_size <= ti->class_size);

        memcpy(ti->class, parent->class, parent->class_size);

        ti->class->interfaces = NULL;

        for (e = parent->class->interfaces; e; e = e->next) {

            InterfaceClass *iface = e->data;

            ObjectClass *klass = OBJECT_CLASS(iface);

            type_initialize_interface(ti, iface->interface_type, klass->type);

        }

        for (i = 0; i < ti->num_interfaces; i++) {

            TypeImpl *t = type_get_by_name(ti->interfaces[i].typename);

            for (e = ti->class->interfaces; e; e = e->next) {

                TypeImpl *target_type = OBJECT_CLASS(e->data)->type;

                if (type_is_ancestor(target_type, t)) {

                    break;

                }

            }

            if (e) {

                continue;

            }

            type_initialize_interface(ti, t, t);

        }

    }

    ti->class->type = ti;

    while (parent) {

        if (parent->class_base_init) {

            parent->class_base_init(ti->class, ti->class_data);

        }

        parent = type_get_parent(parent);

    }

    if (ti->class_init) {

        ti->class_init(ti->class, ti->class_data);

    }

}

static void object_init_with_type(Object *obj, TypeImpl *ti)

{

    if (type_has_parent(ti)) {

        object_init_with_type(obj, type_get_parent(ti));

    }

    if (ti->instance_init) {

        ti->instance_init(obj);

    }

}

static void object_post_init_with_type(Object *obj, TypeImpl *ti)

{

    if (ti->instance_post_init) {

        ti->instance_post_init(obj);

    }

    if (type_has_parent(ti)) {

        object_post_init_with_type(obj, type_get_parent(ti));

    }

}

void object_initialize_with_type(void *data, size_t size, TypeImpl *type)

{

    Object *obj = data;

    g_assert(type != NULL);

    type_initialize(type);

    g_assert(type->instance_size >= sizeof(Object));

    g_assert(type->abstract == false);

    g_assert(size >= type->instance_size);

    memset(obj, 0, type->instance_size);

    obj->class = type->class;

    object_ref(obj);

    QTAILQ_INIT(&obj->properties);

    object_init_with_type(obj, type);

    object_post_init_with_type(obj, type);

}

void object_initialize(void *data, size_t size, const char *typename)

{

    TypeImpl *type = type_get_by_name(typename);

    object_initialize_with_type(data, size, type);

}

static inline bool object_property_is_child(ObjectProperty *prop)

{

    return strstart(prop->type, "child<", NULL);

}

static inline bool object_property_is_link(ObjectProperty *prop)

{

    return strstart(prop->type, "link<", NULL);

}

static void object_property_del_all(Object *obj)

{

    while (!QTAILQ_EMPTY(&obj->properties)) {

        ObjectProperty *prop = QTAILQ_FIRST(&obj->properties);

        QTAILQ_REMOVE(&obj->properties, prop, node);

        if (prop->release) {

            prop->release(obj, prop->name, prop->opaque);

        }

        g_free(prop->name);

        g_free(prop->type);

        g_free(prop);

    }

}

static void object_property_del_child(Object *obj, Object *child, Error **errp)

{

    ObjectProperty *prop;

    QTAILQ_FOREACH(prop, &obj->properties, node) {

        if (object_property_is_child(prop) && prop->opaque == child) {

            object_property_del(obj, prop->name, errp);

            break;

        }

    }

}

void object_unparent(Object *obj)

{

    if (!obj->parent) {

        return;

    }

    object_ref(obj);

    if (obj->class->unparent) {

        (obj->class->unparent)(obj);

    }

    if (obj->parent) {

        object_property_del_child(obj->parent, obj, NULL);

    }

    object_unref(obj);

}

static void object_deinit(Object *obj, TypeImpl *type)

{

    if (type->instance_finalize) {

        type->instance_finalize(obj);

    }

    if (type_has_parent(type)) {

        object_deinit(obj, type_get_parent(type));

    }

}

static void object_finalize(void *data)

{

    Object *obj = data;

    TypeImpl *ti = obj->class->type;

    object_deinit(obj, ti);

    object_property_del_all(obj);

    g_assert(obj->ref == 0);

    if (obj->free) {

        obj->free(obj);

    }

}

Object *object_new_with_type(Type type)

{

    Object *obj;

    g_assert(type != NULL);

    type_initialize(type);

    obj = g_malloc(type->instance_size);

    object_initialize_with_type(obj, type->instance_size, type);

    obj->free = g_free;

    return obj;

}

Object *object_new(const char *typename)

{

    TypeImpl *ti = type_get_by_name(typename);

    return object_new_with_type(ti);

}

Object *object_dynamic_cast(Object *obj, const char *typename)

{

    if (obj && object_class_dynamic_cast(object_get_class(obj), typename)) {

        return obj;

    }

    return NULL;

}

Object *object_dynamic_cast_assert(Object *obj, const char *typename,

                                   const char *file, int line, const char *func)

{

    trace_object_dynamic_cast_assert(obj ? obj->class->type->name : "(null)",

                                     typename, file, line, func);

#ifdef CONFIG_QOM_CAST_DEBUG

    int i;

    Object *inst;

    for (i = 0; obj && i < OBJECT_CLASS_CAST_CACHE; i++) {

        if (obj->class->object_cast_cache[i] == typename) {

            goto out;

        }

    }

    inst = object_dynamic_cast(obj, typename);

    if (!inst && obj) {

        fprintf(stderr, "%s:%d:%s: Object %p is not an instance of type %s\n",

                file, line, func, obj, typename);

        abort();

    }

    assert(obj == inst);

    if (obj && obj == inst) {

        for (i = 1; i < OBJECT_CLASS_CAST_CACHE; i++) {

            obj->class->object_cast_cache[i - 1] =

                    obj->class->object_cast_cache[i];

        }

        obj->class->object_cast_cache[i - 1] = typename;

    }

out:

#endif

    return obj;

}

ObjectClass *object_class_dynamic_cast(ObjectClass *class,

                                       const char *typename)

{

    ObjectClass *ret = NULL;

    TypeImpl *target_type;

    TypeImpl *type;

    if (!class) {

        return NULL;

    }

    /* A simple fast path that can trigger a lot for leaf classes.  */

    type = class->type;

    if (type->name == typename) {

        return class;

    }

    target_type = type_get_by_name(typename);

    if (!target_type) {

        /* target class type unknown, so fail the cast */

        return NULL;

    }

    if (type->class->interfaces &&

            type_is_ancestor(target_type, type_interface)) {

        int found = 0;

        GSList *i;

        for (i = class->interfaces; i; i = i->next) {

            ObjectClass *target_class = i->data;

            if (type_is_ancestor(target_class->type, target_type)) {

                ret = target_class;

                found++;

            }

         }

        /* The match was ambiguous, don't allow a cast */

        if (found > 1) {

            ret = NULL;

        }

    } else if (type_is_ancestor(type, target_type)) {

        ret = class;

    }

    return ret;

}

ObjectClass *object_class_dynamic_cast_assert(ObjectClass *class,

                                              const char *typename,

                                              const char *file, int line,

                                              const char *func)

{

    ObjectClass *ret;

    trace_object_class_dynamic_cast_assert(class ? class->type->name : "(null)",

                                           typename, file, line, func);

#ifdef CONFIG_QOM_CAST_DEBUG

    int i;

    for (i = 0; class && i < OBJECT_CLASS_CAST_CACHE; i++) {

        if (class->class_cast_cache[i] == typename) {

            ret = class;

            goto out;

        }

    }

#else

    if (!class || !class->interfaces) {

        return class;

    }

#endif

    ret = object_class_dynamic_cast(class, typename);

    if (!ret && class) {

        fprintf(stderr, "%s:%d:%s: Object %p is not an instance of type %s\n",

                file, line, func, class, typename);

        abort();

    }

#ifdef CONFIG_QOM_CAST_DEBUG

    if (class && ret == class) {

        for (i = 1; i < OBJECT_CLASS_CAST_CACHE; i++) {

            class->class_cast_cache[i - 1] = class->class_cast_cache[i];

        }

        class->class_cast_cache[i - 1] = typename;

    }

out:

#endif

    return ret;

}

const char *object_get_typename(Object *obj)

{

    return obj->class->type->name;

}

ObjectClass *object_get_class(Object *obj)

{

    return obj->class;

}

bool object_class_is_abstract(ObjectClass *klass)

{

    return klass->type->abstract;

}

const char *object_class_get_name(ObjectClass *klass)

{

    return klass->type->name;

}

ObjectClass *object_class_by_name(const char *typename)

{

    TypeImpl *type = type_get_by_name(typename);

    if (!type) {

        return NULL;

    }

    type_initialize(type);

    return type->class;

}

ObjectClass *object_class_get_parent(ObjectClass *class)

{

    TypeImpl *type = type_get_parent(class->type);

    if (!type) {

        return NULL;

    }

    type_initialize(type);

    return type->class;

}

typedef struct OCFData

{

    void (*fn)(ObjectClass *klass, void *opaque);

    const char *implements_type;

    bool include_abstract;

    void *opaque;

} OCFData;

static void object_class_foreach_tramp(gpointer key, gpointer value,

                                       gpointer opaque)

{

    OCFData *data = opaque;

    TypeImpl *type = value;

    ObjectClass *k;

    type_initialize(type);

    k = type->class;

    if (!data->include_abstract && type->abstract) {

        return;

    }

    if (data->implements_type && 

        !object_class_dynamic_cast(k, data->implements_type)) {

        return;

    }

    data->fn(k, data->opaque);

}

void object_class_foreach(void (*fn)(ObjectClass *klass, void *opaque),

                          const char *implements_type, bool include_abstract,

                          void *opaque)

{

    OCFData data = { fn, implements_type, include_abstract, opaque };

    enumerating_types = true;

    g_hash_table_foreach(type_table_get(), object_class_foreach_tramp, &data);

    enumerating_types = false;

}

int object_child_foreach(Object *obj, int (*fn)(Object *child, void *opaque),

                         void *opaque)

{

    ObjectProperty *prop;

    int ret = 0;

    QTAILQ_FOREACH(prop, &obj->properties, node) {

        if (object_property_is_child(prop)) {

            ret = fn(prop->opaque, opaque);

            if (ret != 0) {

                break;

            }

        }

    }

    return ret;

}

static void object_class_get_list_tramp(ObjectClass *klass, void *opaque)

{

    GSList **list = opaque;

    *list = g_slist_prepend(*list, klass);

}

GSList *object_class_get_list(const char *implements_type,

                              bool include_abstract)

{

    GSList *list = NULL;

    object_class_foreach(object_class_get_list_tramp,

                         implements_type, include_abstract, &list);

    return list;

}

void object_ref(Object *obj)

{

     atomic_inc(&obj->ref);

}

void object_unref(Object *obj)

{

    g_assert(obj->ref > 0);

    /* parent always holds a reference to its children */

    if (atomic_fetch_dec(&obj->ref) == 1) {

        object_finalize(obj);

    }

}

void object_property_add(Object *obj, const char *name, const char *type,

                         ObjectPropertyAccessor *get,

                         ObjectPropertyAccessor *set,

                         ObjectPropertyRelease *release,

                         void *opaque, Error **errp)

{

    ObjectProperty *prop;

    QTAILQ_FOREACH(prop, &obj->properties, node) {

        if (strcmp(prop->name, name) == 0) {

            error_setg(errp, "attempt to add duplicate property '%s'"

                       " to object (type '%s')", name,

                       object_get_typename(obj));

            return;

        }

    }

    prop = g_malloc0(sizeof(*prop));

    prop->name = g_strdup(name);

    prop->type = g_strdup(type);

    prop->get = get;

    prop->set = set;

    prop->release = release;

    prop->opaque = opaque;

    QTAILQ_INSERT_TAIL(&obj->properties, prop, node);

}

ObjectProperty *object_property_find(Object *obj, const char *name,

                                     Error **errp)

{

    ObjectProperty *prop;

    QTAILQ_FOREACH(prop, &obj->properties, node) {

        if (strcmp(prop->name, name) == 0) {

            return prop;

        }

    }

    error_set(errp, QERR_PROPERTY_NOT_FOUND, "", name);

    return NULL;

}

void object_property_del(Object *obj, const char *name, Error **errp)

{

    ObjectProperty *prop = object_property_find(obj, name, errp);

    if (prop == NULL) {

        return;

    }

    if (prop->release) {

        prop->release(obj, name, prop->opaque);

    }

    QTAILQ_REMOVE(&obj->properties, prop, node);

    g_free(prop->name);

    g_free(prop->type);

    g_free(prop);

}

void object_property_get(Object *obj, Visitor *v, const char *name,

                         Error **errp)

{

    ObjectProperty *prop = object_property_find(obj, name, errp);

    if (prop == NULL) {

        return;

    }

    if (!prop->get) {

        error_set(errp, QERR_PERMISSION_DENIED);

    } else {

        prop->get(obj, v, prop->opaque, name, errp);

    }

}

void object_property_set(Object *obj, Visitor *v, const char *name,

                         Error **errp)

{

    ObjectProperty *prop = object_property_find(obj, name, errp);

    if (prop == NULL) {

        return;

    }

    if (!prop->set) {

        error_set(errp, QERR_PERMISSION_DENIED);

    } else {

        prop->set(obj, v, prop->opaque, name, errp);

    }

}

void object_property_set_str(Object *obj, const char *value,

                             const char *name, Error **errp)

{

    QString *qstr = qstring_from_str(value);

    object_property_set_qobject(obj, QOBJECT(qstr), name, errp);

    QDECREF(qstr);

}

char *object_property_get_str(Object *obj, const char *name,

                              Error **errp)

{

    QObject *ret = object_property_get_qobject(obj, name, errp);

    QString *qstring;

    char *retval;

    if (!ret) {

        return NULL;

    }

    qstring = qobject_to_qstring(ret);

    if (!qstring) {

        error_set(errp, QERR_INVALID_PARAMETER_TYPE, name, "string");

        retval = NULL;

    } else {

        retval = g_strdup(qstring_get_str(qstring));

    }

    QDECREF(qstring);

    return retval;

}

void object_property_set_link(Object *obj, Object *value,

                              const char *name, Error **errp)

{

    gchar *path = object_get_canonical_path(value);

    object_property_set_str(obj, path, name, errp);

    g_free(path);

}

Object *object_property_get_link(Object *obj, const char *name,

                                 Error **errp)

{

    char *str = object_property_get_str(obj, name, errp);

    Object *target = NULL;

    if (str && *str) {

        target = object_resolve_path(str, NULL);

        if (!target) {

            error_set(errp, QERR_DEVICE_NOT_FOUND, str);

        }

    }

    g_free(str);

    return target;

}

void object_property_set_bool(Object *obj, bool value,

                              const char *name, Error **errp)

{

    QBool *qbool = qbool_from_int(value);

    object_property_set_qobject(obj, QOBJECT(qbool), name, errp);

    QDECREF(qbool);

}

bool object_property_get_bool(Object *obj, const char *name,

                              Error **errp)

{

    QObject *ret = object_property_get_qobject(obj, name, errp);

    QBool *qbool;

    bool retval;

    if (!ret) {

        return false;

    }

    qbool = qobject_to_qbool(ret);

    if (!qbool) {

        error_set(errp, QERR_INVALID_PARAMETER_TYPE, name, "boolean");

        retval = false;

    } else {

        retval = qbool_get_int(qbool);

    }

    QDECREF(qbool);

    return retval;

}

void object_property_set_int(Object *obj, int64_t value,

                             const char *name, Error **errp)

{

    QInt *qint = qint_from_int(value);

    object_property_set_qobject(obj, QOBJECT(qint), name, errp);

    QDECREF(qint);

}

int64_t object_property_get_int(Object *obj, const char *name,

                                Error **errp)

{

    QObject *ret = object_property_get_qobject(obj, name, errp);

    QInt *qint;

    int64_t retval;

    if (!ret) {

        return -1;

    }

    qint = qobject_to_qint(ret);

    if (!qint) {

        error_set(errp, QERR_INVALID_PARAMETER_TYPE, name, "int");

        retval = -1;

    } else {

        retval = qint_get_int(qint);

    }

    QDECREF(qint);

    return retval;

}

void object_property_parse(Object *obj, const char *string,

                           const char *name, Error **errp)

{

    StringInputVisitor *mi;

    mi = string_input_visitor_new(string);

    object_property_set(obj, string_input_get_visitor(mi), name, errp);

    string_input_visitor_cleanup(mi);

}

char *object_property_print(Object *obj, const char *name,

                            Error **errp)

{

    StringOutputVisitor *mo;

    char *string;

    mo = string_output_visitor_new();

    object_property_get(obj, string_output_get_visitor(mo), name, errp);

    string = string_output_get_string(mo);

    string_output_visitor_cleanup(mo);

    return string;

}

const char *object_property_get_type(Object *obj, const char *name, Error **errp)

{

    ObjectProperty *prop = object_property_find(obj, name, errp);

    if (prop == NULL) {

        return NULL;

    }

    return prop->type;

}

Object *object_get_root(void)

{

    static Object *root;

    if (!root) {

        root = object_new("container");

    }

    return root;

}

static void object_get_child_property(Object *obj, Visitor *v, void *opaque,

                                      const char *name, Error **errp)

{

    Object *child = opaque;

    gchar *path;

    path = object_get_canonical_path(child);

    visit_type_str(v, &path, name, errp);

    g_free(path);

}

static void object_finalize_child_property(Object *obj, const char *name,

                                           void *opaque)

{

    Object *child = opaque;

    object_unref(child);

}

void object_property_add_child(Object *obj, const char *name,

                               Object *child, Error **errp)

{

    Error *local_err = NULL;

    gchar *type;

    type = g_strdup_printf("child<%s>", object_get_typename(OBJECT(child)));

    object_property_add(obj, name, type, object_get_child_property, NULL,

                        object_finalize_child_property, child, &local_err);

    if (local_err) {

        error_propagate(errp, local_err);

        goto out;

    }

    object_ref(child);

    g_assert(child->parent == NULL);

    child->parent = obj;

out:

    g_free(type);

}

static void object_get_link_property(Object *obj, Visitor *v, void *opaque,

                                     const char *name, Error **errp)

{

    Object **child = opaque;

    gchar *path;

    if (*child) {

        path = object_get_canonical_path(*child);

        visit_type_str(v, &path, name, errp);

        g_free(path);

    } else {

        path = (gchar *)"";

        visit_type_str(v, &path, name, errp);

    }

}

static void object_set_link_property(Object *obj, Visitor *v, void *opaque,

                                     const char *name, Error **errp)

{

    Object **child = opaque;

    Object *old_target;

    bool ambiguous = false;

    const char *type;

    char *path;

    gchar *target_type;

    type = object_property_get_type(obj, name, NULL);

    visit_type_str(v, &path, name, errp);

    old_target = *child;

    *child = NULL;

    if (strcmp(path, "") != 0) {

        Object *target;

        /* Go from link<FOO> to FOO.  */

        target_type = g_strndup(&type[5], strlen(type) - 6);

        target = object_resolve_path_type(path, target_type, &ambiguous);

        if (ambiguous) {

            error_set(errp, QERR_AMBIGUOUS_PATH, path);

        } else if (target) {

            object_ref(target);

            *child = target;

        } else {

            target = object_resolve_path(path, &ambiguous);

            if (target || ambiguous) {

                error_set(errp, QERR_INVALID_PARAMETER_TYPE, name, target_type);

            } else {

                error_set(errp, QERR_DEVICE_NOT_FOUND, path);

            }

        }

        g_free(target_type);

    }

    g_free(path);

    if (old_target != NULL) {

        object_unref(old_target);

    }

}

void object_property_add_link(Object *obj, const char *name,

                              const char *type, Object **child,

                              Error **errp)

{

    gchar *full_type;

    full_type = g_strdup_printf("link<%s>", type);

    object_property_add(obj, name, full_type,

                        object_get_link_property,

                        object_set_link_property,

                        NULL, child, errp);

    g_free(full_type);

}

gchar *object_get_canonical_path(Object *obj)

{

    Object *root = object_get_root();

    char *newpath = NULL, *path = NULL;

    while (obj != root) {

        ObjectProperty *prop = NULL;

        g_assert(obj->parent != NULL);

        QTAILQ_FOREACH(prop, &obj->parent->properties, node) {

            if (!object_property_is_child(prop)) {

                continue;

            }

            if (prop->opaque == obj) {

                if (path) {

                    newpath = g_strdup_printf("%s/%s", prop->name, path);

                    g_free(path);

                    path = newpath;

                } else {

                    path = g_strdup(prop->name);

                }

                break;

            }

        }

        g_assert(prop != NULL);

        obj = obj->parent;

    }

    newpath = g_strdup_printf("/%s", path);

    g_free(path);

    return newpath;

}

Object *object_resolve_path_component(Object *parent, const gchar *part)

{

    ObjectProperty *prop = object_property_find(parent, part, NULL);

    if (prop == NULL) {

        return NULL;

    }

    if (object_property_is_link(prop)) {

        return *(Object **)prop->opaque;

    } else if (object_property_is_child(prop)) {

        return prop->opaque;

    } else {

        return NULL;

    }

}

static Object *object_resolve_abs_path(Object *parent,

                                          gchar **parts,

                                          const char *typename,

                                          int index)

{

    Object *child;

    if (parts[index] == NULL) {

        return object_dynamic_cast(parent, typename);

    }

    if (strcmp(parts[index], "") == 0) {

        return object_resolve_abs_path(parent, parts, typename, index + 1);

    }

    child = object_resolve_path_component(parent, parts[index]);

    if (!child) {

        return NULL;

    }

    return object_resolve_abs_path(child, parts, typename, index + 1);

}

static Object *object_resolve_partial_path(Object *parent,

                                              gchar **parts,

                                              const char *typename,

                                              bool *ambiguous)

{

    Object *obj;

    ObjectProperty *prop;

    obj = object_resolve_abs_path(parent, parts, typename, 0);

    QTAILQ_FOREACH(prop, &parent->properties, node) {

        Object *found;

        if (!object_property_is_child(prop)) {

            continue;

        }

        found = object_resolve_partial_path(prop->opaque, parts,

                                            typename, ambiguous);

        if (found) {

            if (obj) {

                if (ambiguous) {

                    *ambiguous = true;

                }

                return NULL;

            }

            obj = found;

        }

        if (ambiguous && *ambiguous) {

            return NULL;

        }

    }

    return obj;

}

Object *object_resolve_path_type(const char *path, const char *typename,

                                 bool *ambiguous)

{

    Object *obj;

    gchar **parts;

    parts = g_strsplit(path, "/", 0);

    assert(parts);

    if (parts[0] == NULL || strcmp(parts[0], "") != 0) {

        if (ambiguous) {

            *ambiguous = false;

        }

        obj = object_resolve_partial_path(object_get_root(), parts,

                                          typename, ambiguous);

    } else {

        obj = object_resolve_abs_path(object_get_root(), parts, typename, 1);

    }

    g_strfreev(parts);

    return obj;

}

Object *object_resolve_path(const char *path, bool *ambiguous)

{

    return object_resolve_path_type(path, TYPE_OBJECT, ambiguous);

}

typedef struct StringProperty

{

    char *(*get)(Object *, Error **);

    void (*set)(Object *, const char *, Error **);

} StringProperty;

static void property_get_str(Object *obj, Visitor *v, void *opaque,

                             const char *name, Error **errp)

{

    StringProperty *prop = opaque;

    char *value;

    value = prop->get(obj, errp);

    if (value) {

        visit_type_str(v, &value, name, errp);

        g_free(value);

    }

}

static void property_set_str(Object *obj, Visitor *v, void *opaque,

                             const char *name, Error **errp)

{

    StringProperty *prop = opaque;

    char *value;

    Error *local_err = NULL;

    visit_type_str(v, &value, name, &local_err);

    if (local_err) {

        error_propagate(errp, local_err);

        return;

    }

    prop->set(obj, value, errp);

    g_free(value);

}

static void property_release_str(Object *obj, const char *name,

                                 void *opaque)

{

    StringProperty *prop = opaque;

    g_free(prop);

}

void object_property_add_str(Object *obj, const char *name,

                           char *(*get)(Object *, Error **),

                           void (*set)(Object *, const char *, Error **),

                           Error **errp)

{

    StringProperty *prop = g_malloc0(sizeof(*prop));

    prop->get = get;

    prop->set = set;

    object_property_add(obj, name, "string",

                        get ? property_get_str : NULL,

                        set ? property_set_str : NULL,

                        property_release_str,

                        prop, errp);

}

typedef struct BoolProperty

{

    bool (*get)(Object *, Error **);

    void (*set)(Object *, bool, Error **);

} BoolProperty;

static void property_get_bool(Object *obj, Visitor *v, void *opaque,

                              const char *name, Error **errp)

{

    BoolProperty *prop = opaque;

    bool value;

    value = prop->get(obj, errp);

    visit_type_bool(v, &value, name, errp);

}

static void property_set_bool(Object *obj, Visitor *v, void *opaque,

                              const char *name, Error **errp)

{

    BoolProperty *prop = opaque;

    bool value;

    Error *local_err = NULL;

    visit_type_bool(v, &value, name, &local_err);

    if (local_err) {

        error_propagate(errp, local_err);

        return;

    }

    prop->set(obj, value, errp);

}

static void property_release_bool(Object *obj, const char *name,

                                  void *opaque)

{

    BoolProperty *prop = opaque;

    g_free(prop);

}

void object_property_add_bool(Object *obj, const char *name,

                              bool (*get)(Object *, Error **),

                              void (*set)(Object *, bool, Error **),

                              Error **errp)

{

    BoolProperty *prop = g_malloc0(sizeof(*prop));

    prop->get = get;

    prop->set = set;

    object_property_add(obj, name, "bool",

                        get ? property_get_bool : NULL,

                        set ? property_set_bool : NULL,

                        property_release_bool,

                        prop, errp);

}

static char *qdev_get_type(Object *obj, Error **errp)

{

    return g_strdup(object_get_typename(obj));

}

static void property_get_uint8_ptr(Object *obj, Visitor *v,

                                   void *opaque, const char *name,

                                   Error **errp)

{

    uint8_t value = *(uint8_t *)opaque;

    visit_type_uint8(v, &value, name, errp);

}

static void property_get_uint16_ptr(Object *obj, Visitor *v,

                                   void *opaque, const char *name,

                                   Error **errp)

{

    uint16_t value = *(uint16_t *)opaque;

    visit_type_uint16(v, &value, name, errp);

}

static void property_get_uint32_ptr(Object *obj, Visitor *v,

                                   void *opaque, const char *name,

                                   Error **errp)

{

    uint32_t value = *(uint32_t *)opaque;

    visit_type_uint32(v, &value, name, errp);

}

static void property_get_uint64_ptr(Object *obj, Visitor *v,

                                   void *opaque, const char *name,

                                   Error **errp)

{

    uint64_t value = *(uint64_t *)opaque;

    visit_type_uint64(v, &value, name, errp);

}

void object_property_add_uint8_ptr(Object *obj, const char *name,

                                   const uint8_t *v, Error **errp)

{

    object_property_add(obj, name, "uint8", property_get_uint8_ptr,

                        NULL, NULL, (void *)v, errp);

}

void object_property_add_uint16_ptr(Object *obj, const char *name,

                                    const uint16_t *v, Error **errp)

{

    object_property_add(obj, name, "uint16", property_get_uint16_ptr,

                        NULL, NULL, (void *)v, errp);

}

void object_property_add_uint32_ptr(Object *obj, const char *name,

                                    const uint32_t *v, Error **errp)

{

    object_property_add(obj, name, "uint32", property_get_uint32_ptr,