qemu/include/qapi/visitor.h
Michael Roth cee2dedb85 qapi: add visit_start_union and visit_end_union
In some cases an input visitor might bail out on filling out a
struct for various reasons, such as missing fields when running
in strict mode. In the case of a QAPI Union type, this may lead
to cases where the .kind field which encodes the union type
is uninitialized. Subsequently, other visitors, such as the
dealloc visitor, may use this .kind value as if it were
initialized, leading to assumptions about the union type which
in this case may lead to segfaults. For example, freeing an
integer value.

However, we can generally rely on the fact that the always-present
.data void * field that we generate for these union types will
always be NULL in cases where .kind is uninitialized (at least,
there shouldn't be a reason where we'd do this purposefully).

So pass this information on to Visitor implementation via these
optional start_union/end_union interfaces so this information
can be used to guard against the situation above. We will make
use of this information in a subsequent patch for the dealloc
visitor.

Cc: qemu-stable@nongnu.org
Reported-by: Fam Zheng <famz@redhat.com>
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2014-09-26 13:14:10 -04:00

65 lines
2.8 KiB
C

/*
* Core Definitions for QAPI Visitor Classes
*
* 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.
*
*/
#ifndef QAPI_VISITOR_CORE_H
#define QAPI_VISITOR_CORE_H
#include "qemu/typedefs.h"
#include "qapi/qmp/qobject.h"
#include "qapi/error.h"
#include <stdlib.h>
typedef struct GenericList
{
union {
void *value;
uint64_t padding;
};
struct GenericList *next;
} GenericList;
void visit_start_handle(Visitor *v, void **obj, const char *kind,
const char *name, Error **errp);
void visit_end_handle(Visitor *v, Error **errp);
void visit_start_struct(Visitor *v, void **obj, const char *kind,
const char *name, size_t size, Error **errp);
void visit_end_struct(Visitor *v, Error **errp);
void visit_start_implicit_struct(Visitor *v, void **obj, size_t size,
Error **errp);
void visit_end_implicit_struct(Visitor *v, Error **errp);
void visit_start_list(Visitor *v, const char *name, Error **errp);
GenericList *visit_next_list(Visitor *v, GenericList **list, Error **errp);
void visit_end_list(Visitor *v, Error **errp);
void visit_optional(Visitor *v, bool *present, const char *name,
Error **errp);
void visit_get_next_type(Visitor *v, int *obj, const int *qtypes,
const char *name, Error **errp);
void visit_type_enum(Visitor *v, int *obj, const char *strings[],
const char *kind, const char *name, Error **errp);
void visit_type_int(Visitor *v, int64_t *obj, const char *name, Error **errp);
void visit_type_uint8(Visitor *v, uint8_t *obj, const char *name, Error **errp);
void visit_type_uint16(Visitor *v, uint16_t *obj, const char *name, Error **errp);
void visit_type_uint32(Visitor *v, uint32_t *obj, const char *name, Error **errp);
void visit_type_uint64(Visitor *v, uint64_t *obj, const char *name, Error **errp);
void visit_type_int8(Visitor *v, int8_t *obj, const char *name, Error **errp);
void visit_type_int16(Visitor *v, int16_t *obj, const char *name, Error **errp);
void visit_type_int32(Visitor *v, int32_t *obj, const char *name, Error **errp);
void visit_type_int64(Visitor *v, int64_t *obj, const char *name, Error **errp);
void visit_type_size(Visitor *v, uint64_t *obj, const char *name, Error **errp);
void visit_type_bool(Visitor *v, bool *obj, const char *name, Error **errp);
void visit_type_str(Visitor *v, char **obj, const char *name, Error **errp);
void visit_type_number(Visitor *v, double *obj, const char *name, Error **errp);
bool visit_start_union(Visitor *v, bool data_present, Error **errp);
void visit_end_union(Visitor *v, bool data_present, Error **errp);
#endif