qemu/qom/object_interfaces.c
Markus Armbruster bd74ecd1c3 qom: Fix default values in help
Output of default values in device help is broken:

    $ ./qemu-system-x86_64 -S -display none -monitor stdio
    QEMU 5.2.50 monitor - type 'help' for more information
    (qemu) device_add pvpanic,help
    pvpanic options:
      events=<uint8>         -  (default: (null))
      ioport=<uint16>        -  (default: (null))
      pvpanic[0]=<child<qemu:memory-region>>

The "(null)" is glibc printing a null pointer.  Other systems crash
instead.  Having a help request crash a running VM can really spoil
your day.

Root cause is a botched replacement of qstring_free() by
g_string_free(): to get the string back, we need to pass true to the
former, but false to the latter.  Fix the argument.

Fixes: eab3a4678b
Reported-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Message-Id: <20210324084130.3986072-1-armbru@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
2021-04-01 14:28:39 +02:00

350 lines
8.8 KiB
C

#include "qemu/osdep.h"
#include "qemu/cutils.h"
#include "qapi/error.h"
#include "qapi/qapi-commands-qom.h"
#include "qapi/qapi-visit-qom.h"
#include "qapi/qmp/qdict.h"
#include "qapi/qmp/qerror.h"
#include "qapi/qmp/qjson.h"
#include "qapi/qobject-input-visitor.h"
#include "qapi/qobject-output-visitor.h"
#include "qom/object_interfaces.h"
#include "qemu/help_option.h"
#include "qemu/id.h"
#include "qemu/module.h"
#include "qemu/option.h"
#include "qemu/qemu-print.h"
#include "qapi/opts-visitor.h"
#include "qemu/config-file.h"
#include "qemu/qemu-print.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)
{
ERRP_GUARD();
Object *obj;
ObjectClass *klass;
const QDictEntry *e;
Error *local_err = NULL;
if (id != NULL && !id_wellformed(id)) {
error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "id", "an identifier");
error_append_hint(errp, "Identifiers consist of letters, digits, "
"'-', '.', '_', starting with a letter.\n");
return 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;
}
void user_creatable_add_qapi(ObjectOptions *options, Error **errp)
{
Visitor *v;
QObject *qobj;
QDict *props;
Object *obj;
v = qobject_output_visitor_new(&qobj);
visit_type_ObjectOptions(v, NULL, &options, &error_abort);
visit_complete(v, &qobj);
visit_free(v);
props = qobject_to(QDict, qobj);
qdict_del(props, "qom-type");
qdict_del(props, "id");
v = qobject_input_visitor_new(QOBJECT(props));
obj = user_creatable_add_type(ObjectType_str(options->qom_type),
options->id, props, v, errp);
object_unref(obj);
qobject_unref(qobj);
visit_free(v);
}
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 = g_string_free(qobject_to_json(defval),
false);
g_string_append_printf(str, " (default: %s)", def_json);
}
return g_string_free(str, false);
}
static void user_creatable_print_types(void)
{
GSList *l, *list;
qemu_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);
qemu_printf(" %s\n", object_class_get_name(oc));
}
g_slist_free(list);
}
static bool user_creatable_print_type_properites(const char *type)
{
ObjectClass *klass;
ObjectPropertyIterator iter;
ObjectProperty *prop;
GPtrArray *array;
int i;
klass = object_class_by_name(type);
if (!klass) {
return false;
}
array = g_ptr_array_new();
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) {
qemu_printf("%s options:\n", type);
} else {
qemu_printf("There are no options for %s.\n", type);
}
for (i = 0; i < array->len; i++) {
qemu_printf("%s\n", (char *)array->pdata[i]);
}
g_ptr_array_set_free_func(array, g_free);
g_ptr_array_free(array, true);
return true;
}
bool user_creatable_print_help(const char *type, QemuOpts *opts)
{
if (is_help_option(type)) {
user_creatable_print_types();
return true;
}
if (qemu_opt_has_help_opt(opts)) {
return user_creatable_print_type_properites(type);
}
return false;
}
static void user_creatable_print_help_from_qdict(QDict *args)
{
const char *type = qdict_get_try_str(args, "qom-type");
if (!type || !user_creatable_print_type_properites(type)) {
user_creatable_print_types();
}
}
ObjectOptions *user_creatable_parse_str(const char *optarg, Error **errp)
{
ERRP_GUARD();
QObject *obj;
bool help;
Visitor *v;
ObjectOptions *options;
if (optarg[0] == '{') {
obj = qobject_from_json(optarg, errp);
if (!obj) {
return NULL;
}
v = qobject_input_visitor_new(obj);
} else {
QDict *args = keyval_parse(optarg, "qom-type", &help, errp);
if (*errp) {
return NULL;
}
if (help) {
user_creatable_print_help_from_qdict(args);
qobject_unref(args);
return NULL;
}
obj = QOBJECT(args);
v = qobject_input_visitor_new_keyval(obj);
}
visit_type_ObjectOptions(v, NULL, &options, errp);
visit_free(v);
qobject_unref(obj);
return options;
}
bool user_creatable_add_from_str(const char *optarg, Error **errp)
{
ERRP_GUARD();
ObjectOptions *options;
options = user_creatable_parse_str(optarg, errp);
if (!options) {
return false;
}
user_creatable_add_qapi(options, errp);
qapi_free_ObjectOptions(options);
return !*errp;
}
void user_creatable_process_cmdline(const char *optarg)
{
if (!user_creatable_add_from_str(optarg, &error_fatal)) {
/* Help was printed */
exit(EXIT_SUCCESS);
}
}
bool user_creatable_del(const char *id, Error **errp)
{
QemuOptsList *opts_list;
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
*/
opts_list = qemu_find_opts_err("object", NULL);
if (opts_list) {
qemu_opts_del(qemu_opts_find(opts_list, 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)