qemu/qapi/qmp-output-visitor.c
Eric Blake f755dea79d qapi: Make all visitors supply uint64 callbacks
Our qapi visitor contract supports multiple integer visitors,
but left the type_uint64 visitor as optional (falling back on
type_int64); which in turn can lead to awkward behavior with
numbers larger than INT64_MAX (the user has to be aware of
twos complement, and deal with negatives).

This patch does not address the disparity in handling large
values as negatives.  It merely moves the fallback from uint64
to int64 from the visitor core to the visitors, where the issue
can actually be fixed, by implementing the missing type_uint64()
callbacks on top of the respective type_int64() callbacks, and
with a FIXME comment explaining why that's wrong.

With that done, we now have a type_uint64() callback in every
driver, so we can make it mandatory from the core.  And although
the type_int64() callback can cover the entire valid range of
type_uint{8,16,32} on valid user input, using type_uint64() to
avoid mixed signedness makes more sense.

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1454075341-13658-15-git-send-email-eblake@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-02-08 17:29:55 +01:00

264 lines
6.6 KiB
C

/*
* Core Definitions for QAPI/QMP Command Registry
*
* Copyright IBM, Corp. 2011
*
* Authors:
* Anthony Liguori <aliguori@us.ibm.com>
*
* This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
* See the COPYING.LIB file in the top-level directory.
*
*/
#include "qemu/osdep.h"
#include "qapi/qmp-output-visitor.h"
#include "qapi/visitor-impl.h"
#include "qemu/queue.h"
#include "qemu-common.h"
#include "qapi/qmp/types.h"
typedef struct QStackEntry
{
QObject *value;
bool is_list_head;
QTAILQ_ENTRY(QStackEntry) node;
} QStackEntry;
typedef QTAILQ_HEAD(QStack, QStackEntry) QStack;
struct QmpOutputVisitor
{
Visitor visitor;
QStack stack;
};
#define qmp_output_add(qov, name, value) \
qmp_output_add_obj(qov, name, QOBJECT(value))
#define qmp_output_push(qov, value) qmp_output_push_obj(qov, QOBJECT(value))
static QmpOutputVisitor *to_qov(Visitor *v)
{
return container_of(v, QmpOutputVisitor, visitor);
}
static void qmp_output_push_obj(QmpOutputVisitor *qov, QObject *value)
{
QStackEntry *e = g_malloc0(sizeof(*e));
e->value = value;
if (qobject_type(e->value) == QTYPE_QLIST) {
e->is_list_head = true;
}
QTAILQ_INSERT_HEAD(&qov->stack, e, node);
}
static QObject *qmp_output_pop(QmpOutputVisitor *qov)
{
QStackEntry *e = QTAILQ_FIRST(&qov->stack);
QObject *value;
QTAILQ_REMOVE(&qov->stack, e, node);
value = e->value;
g_free(e);
return value;
}
static QObject *qmp_output_first(QmpOutputVisitor *qov)
{
QStackEntry *e = QTAILQ_LAST(&qov->stack, QStack);
/*
* FIXME Wrong, because qmp_output_get_qobject() will increment
* the refcnt *again*. We need to think through how visitors
* handle null.
*/
if (!e) {
return qnull();
}
return e->value;
}
static QObject *qmp_output_last(QmpOutputVisitor *qov)
{
QStackEntry *e = QTAILQ_FIRST(&qov->stack);
return e->value;
}
static void qmp_output_add_obj(QmpOutputVisitor *qov, const char *name,
QObject *value)
{
QObject *cur;
if (QTAILQ_EMPTY(&qov->stack)) {
qmp_output_push_obj(qov, value);
return;
}
cur = qmp_output_last(qov);
switch (qobject_type(cur)) {
case QTYPE_QDICT:
qdict_put_obj(qobject_to_qdict(cur), name, value);
break;
case QTYPE_QLIST:
qlist_append_obj(qobject_to_qlist(cur), value);
break;
default:
qobject_decref(qmp_output_pop(qov));
qmp_output_push_obj(qov, value);
break;
}
}
static void qmp_output_start_struct(Visitor *v, void **obj, const char *kind,
const char *name, size_t unused,
Error **errp)
{
QmpOutputVisitor *qov = to_qov(v);
QDict *dict = qdict_new();
qmp_output_add(qov, name, dict);
qmp_output_push(qov, dict);
}
static void qmp_output_end_struct(Visitor *v, Error **errp)
{
QmpOutputVisitor *qov = to_qov(v);
qmp_output_pop(qov);
}
static void qmp_output_start_list(Visitor *v, const char *name, Error **errp)
{
QmpOutputVisitor *qov = to_qov(v);
QList *list = qlist_new();
qmp_output_add(qov, name, list);
qmp_output_push(qov, list);
}
static GenericList *qmp_output_next_list(Visitor *v, GenericList **listp,
Error **errp)
{
GenericList *list = *listp;
QmpOutputVisitor *qov = to_qov(v);
QStackEntry *e = QTAILQ_FIRST(&qov->stack);
assert(e);
if (e->is_list_head) {
e->is_list_head = false;
return list;
}
return list ? list->next : NULL;
}
static void qmp_output_end_list(Visitor *v, Error **errp)
{
QmpOutputVisitor *qov = to_qov(v);
qmp_output_pop(qov);
}
static void qmp_output_type_int64(Visitor *v, int64_t *obj, const char *name,
Error **errp)
{
QmpOutputVisitor *qov = to_qov(v);
qmp_output_add(qov, name, qint_from_int(*obj));
}
static void qmp_output_type_uint64(Visitor *v, uint64_t *obj, const char *name,
Error **errp)
{
/* FIXME: QMP outputs values larger than INT64_MAX as negative */
QmpOutputVisitor *qov = to_qov(v);
qmp_output_add(qov, name, qint_from_int(*obj));
}
static void qmp_output_type_bool(Visitor *v, bool *obj, const char *name,
Error **errp)
{
QmpOutputVisitor *qov = to_qov(v);
qmp_output_add(qov, name, qbool_from_bool(*obj));
}
static void qmp_output_type_str(Visitor *v, char **obj, const char *name,
Error **errp)
{
QmpOutputVisitor *qov = to_qov(v);
if (*obj) {
qmp_output_add(qov, name, qstring_from_str(*obj));
} else {
qmp_output_add(qov, name, qstring_from_str(""));
}
}
static void qmp_output_type_number(Visitor *v, double *obj, const char *name,
Error **errp)
{
QmpOutputVisitor *qov = to_qov(v);
qmp_output_add(qov, name, qfloat_from_double(*obj));
}
static void qmp_output_type_any(Visitor *v, QObject **obj, const char *name,
Error **errp)
{
QmpOutputVisitor *qov = to_qov(v);
qobject_incref(*obj);
qmp_output_add_obj(qov, name, *obj);
}
QObject *qmp_output_get_qobject(QmpOutputVisitor *qov)
{
QObject *obj = qmp_output_first(qov);
if (obj) {
qobject_incref(obj);
}
return obj;
}
Visitor *qmp_output_get_visitor(QmpOutputVisitor *v)
{
return &v->visitor;
}
void qmp_output_visitor_cleanup(QmpOutputVisitor *v)
{
QStackEntry *e, *tmp;
/* The bottom QStackEntry, if any, owns the root QObject. See the
* qmp_output_push_obj() invocations in qmp_output_add_obj(). */
QObject *root = QTAILQ_EMPTY(&v->stack) ? NULL : qmp_output_first(v);
QTAILQ_FOREACH_SAFE(e, &v->stack, node, tmp) {
QTAILQ_REMOVE(&v->stack, e, node);
g_free(e);
}
qobject_decref(root);
g_free(v);
}
QmpOutputVisitor *qmp_output_visitor_new(void)
{
QmpOutputVisitor *v;
v = g_malloc0(sizeof(*v));
v->visitor.start_struct = qmp_output_start_struct;
v->visitor.end_struct = qmp_output_end_struct;
v->visitor.start_list = qmp_output_start_list;
v->visitor.next_list = qmp_output_next_list;
v->visitor.end_list = qmp_output_end_list;
v->visitor.type_enum = output_type_enum;
v->visitor.type_int64 = qmp_output_type_int64;
v->visitor.type_uint64 = qmp_output_type_uint64;
v->visitor.type_bool = qmp_output_type_bool;
v->visitor.type_str = qmp_output_type_str;
v->visitor.type_number = qmp_output_type_number;
v->visitor.type_any = qmp_output_type_any;
QTAILQ_INIT(&v->stack);
return v;
}