qemu-patch-raspberry4/qom/object_interfaces.c
Eric Auger db57fef1e2 qom: Introduce object_property_try_add_child()
object_property_add() does not allow object_property_try_add()
to gracefully fail as &error_abort is passed as an error handle.

However such failure can easily be triggered from the QMP shell when,
for instance, one attempts to create an object with an id that already
exists. This is achieved from the following call path:

qmp_object_add -> user_creatable_add_dict -> user_creatable_add_type ->
object_property_add_child -> object_property_add

For instance, from the qmp-shell, call twice:
object-add qom-type=memory-backend-ram id=mem1 props.size=1073741824
and QEMU aborts.

This behavior is undesired as a user/management application mistake
in reusing a property ID shouldn't result in loss of the VM and live
data within.

This patch introduces a new function, object_property_try_add_child()
which takes an error handle and turn object_property_try_add() into
a non-static one.

Now the call path becomes:

user_creatable_add_type -> object_property_try_add_child ->
object_property_try_add

and the error is returned gracefully to the QMP client.

(QEMU) object-add qom-type=memory-backend-ram id=mem2  props.size=4294967296
{"return": {}}
(QEMU) object-add qom-type=memory-backend-ram id=mem2  props.size=4294967296
{"error": {"class": "GenericError", "desc": "attempt to add duplicate property
'mem2' to object (type 'container')"}}

Signed-off-by: Eric Auger <eric.auger@redhat.com>
Fixes: d2623129a7 ("qom: Drop parameter @errp of object_property_add() & friends")
Reviewed-by: Markus Armbruster <armbru@redhat.com>

Reviewed-by: Greg Kurz <groug@kaod.org>
Tested-by: Greg Kurz <groug@kaod.org>
Message-Id: <20200629193424.30280-2-eric.auger@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-07-10 18:02:16 -04:00

313 lines
8 KiB
C

#include "qemu/osdep.h"
#include "qemu/cutils.h"
#include "qapi/error.h"
#include "qapi/qmp/qdict.h"
#include "qapi/qmp/qerror.h"
#include "qapi/qmp/qjson.h"
#include "qapi/qmp/qstring.h"
#include "qapi/qobject-input-visitor.h"
#include "qom/object_interfaces.h"
#include "qemu/help_option.h"
#include "qemu/module.h"
#include "qemu/option.h"
#include "qapi/opts-visitor.h"
#include "qemu/config-file.h"
bool user_creatable_complete(UserCreatable *uc, Error **errp)
{
UserCreatableClass *ucc = USER_CREATABLE_GET_CLASS(uc);
Error *err = NULL;
if (ucc->complete) {
ucc->complete(uc, &err);
error_propagate(errp, err);
}
return !err;
}
bool user_creatable_can_be_deleted(UserCreatable *uc)
{
UserCreatableClass *ucc = USER_CREATABLE_GET_CLASS(uc);
if (ucc->can_be_deleted) {
return ucc->can_be_deleted(uc);
} else {
return true;
}
}
Object *user_creatable_add_type(const char *type, const char *id,
const QDict *qdict,
Visitor *v, Error **errp)
{
Object *obj;
ObjectClass *klass;
const QDictEntry *e;
Error *local_err = NULL;
klass = object_class_by_name(type);
if (!klass) {
error_setg(errp, "invalid object type: %s", type);
return NULL;
}
if (!object_class_dynamic_cast(klass, TYPE_USER_CREATABLE)) {
error_setg(errp, "object type '%s' isn't supported by object-add",
type);
return NULL;
}
if (object_class_is_abstract(klass)) {
error_setg(errp, "object type '%s' is abstract", type);
return NULL;
}
assert(qdict);
obj = object_new(type);
if (!visit_start_struct(v, NULL, NULL, 0, &local_err)) {
goto out;
}
for (e = qdict_first(qdict); e; e = qdict_next(qdict, e)) {
if (!object_property_set(obj, e->key, v, &local_err)) {
break;
}
}
if (!local_err) {
visit_check_struct(v, &local_err);
}
visit_end_struct(v, NULL);
if (local_err) {
goto out;
}
if (id != NULL) {
object_property_try_add_child(object_get_objects_root(),
id, obj, &local_err);
if (local_err) {
goto out;
}
}
if (!user_creatable_complete(USER_CREATABLE(obj), &local_err)) {
if (id != NULL) {
object_property_del(object_get_objects_root(), id);
}
goto out;
}
out:
if (local_err) {
error_propagate(errp, local_err);
object_unref(obj);
return NULL;
}
return obj;
}
bool user_creatable_add_dict(QDict *qdict, bool keyval, Error **errp)
{
Visitor *v;
Object *obj;
g_autofree char *type = NULL;
g_autofree char *id = NULL;
type = g_strdup(qdict_get_try_str(qdict, "qom-type"));
if (!type) {
error_setg(errp, QERR_MISSING_PARAMETER, "qom-type");
return false;
}
qdict_del(qdict, "qom-type");
id = g_strdup(qdict_get_try_str(qdict, "id"));
if (!id) {
error_setg(errp, QERR_MISSING_PARAMETER, "id");
return false;
}
qdict_del(qdict, "id");
if (keyval) {
v = qobject_input_visitor_new_keyval(QOBJECT(qdict));
} else {
v = qobject_input_visitor_new(QOBJECT(qdict));
}
obj = user_creatable_add_type(type, id, qdict, v, errp);
visit_free(v);
object_unref(obj);
return !!obj;
}
Object *user_creatable_add_opts(QemuOpts *opts, Error **errp)
{
Visitor *v;
QDict *pdict;
Object *obj;
const char *id = qemu_opts_id(opts);
char *type = qemu_opt_get_del(opts, "qom-type");
if (!type) {
error_setg(errp, QERR_MISSING_PARAMETER, "qom-type");
return NULL;
}
if (!id) {
error_setg(errp, QERR_MISSING_PARAMETER, "id");
qemu_opt_set(opts, "qom-type", type, &error_abort);
g_free(type);
return NULL;
}
qemu_opts_set_id(opts, NULL);
pdict = qemu_opts_to_qdict(opts, NULL);
v = opts_visitor_new(opts);
obj = user_creatable_add_type(type, id, pdict, v, errp);
visit_free(v);
qemu_opts_set_id(opts, (char *) id);
qemu_opt_set(opts, "qom-type", type, &error_abort);
g_free(type);
qobject_unref(pdict);
return obj;
}
int user_creatable_add_opts_foreach(void *opaque, QemuOpts *opts, Error **errp)
{
bool (*type_opt_predicate)(const char *, QemuOpts *) = opaque;
Object *obj = NULL;
const char *type;
type = qemu_opt_get(opts, "qom-type");
if (type && type_opt_predicate &&
!type_opt_predicate(type, opts)) {
return 0;
}
obj = user_creatable_add_opts(opts, errp);
if (!obj) {
return -1;
}
object_unref(obj);
return 0;
}
char *object_property_help(const char *name, const char *type,
QObject *defval, const char *description)
{
GString *str = g_string_new(NULL);
g_string_append_printf(str, " %s=<%s>", name, type);
if (description || defval) {
if (str->len < 24) {
g_string_append_printf(str, "%*s", 24 - (int)str->len, "");
}
g_string_append(str, " - ");
}
if (description) {
g_string_append(str, description);
}
if (defval) {
g_autofree char *def_json = qstring_free(qobject_to_json(defval), TRUE);
g_string_append_printf(str, " (default: %s)", def_json);
}
return g_string_free(str, false);
}
bool user_creatable_print_help(const char *type, QemuOpts *opts)
{
ObjectClass *klass;
if (is_help_option(type)) {
GSList *l, *list;
printf("List of user creatable objects:\n");
list = object_class_get_list_sorted(TYPE_USER_CREATABLE, false);
for (l = list; l != NULL; l = l->next) {
ObjectClass *oc = OBJECT_CLASS(l->data);
printf(" %s\n", object_class_get_name(oc));
}
g_slist_free(list);
return true;
}
klass = object_class_by_name(type);
if (klass && qemu_opt_has_help_opt(opts)) {
ObjectPropertyIterator iter;
ObjectProperty *prop;
GPtrArray *array = g_ptr_array_new();
int i;
object_class_property_iter_init(&iter, klass);
while ((prop = object_property_iter_next(&iter))) {
if (!prop->set) {
continue;
}
g_ptr_array_add(array,
object_property_help(prop->name, prop->type,
prop->defval, prop->description));
}
g_ptr_array_sort(array, (GCompareFunc)qemu_pstrcmp0);
if (array->len > 0) {
printf("%s options:\n", type);
} else {
printf("There are no options for %s.\n", type);
}
for (i = 0; i < array->len; i++) {
printf("%s\n", (char *)array->pdata[i]);
}
g_ptr_array_set_free_func(array, g_free);
g_ptr_array_free(array, true);
return true;
}
return false;
}
bool user_creatable_del(const char *id, Error **errp)
{
Object *container;
Object *obj;
container = object_get_objects_root();
obj = object_resolve_path_component(container, id);
if (!obj) {
error_setg(errp, "object '%s' not found", id);
return false;
}
if (!user_creatable_can_be_deleted(USER_CREATABLE(obj))) {
error_setg(errp, "object '%s' is in use, can not be deleted", id);
return false;
}
/*
* if object was defined on the command-line, remove its corresponding
* option group entry
*/
qemu_opts_del(qemu_opts_find(qemu_find_opts_err("object", &error_abort),
id));
object_unparent(obj);
return true;
}
void user_creatable_cleanup(void)
{
object_unparent(object_get_objects_root());
}
static void register_types(void)
{
static const TypeInfo uc_interface_info = {
.name = TYPE_USER_CREATABLE,
.parent = TYPE_INTERFACE,
.class_size = sizeof(UserCreatableClass),
};
type_register_static(&uc_interface_info);
}
type_init(register_types)