unicorn/qemu/qapi/qapi-visit-core.c
Eric Blake 0ec9a5adaf
qapi: Guarantee NULL obj on input visitor callback error
Our existing input visitors were not very consistent on errors in a
function taking 'TYPE **obj'. These are start_struct(),
start_alternate(), type_str(), and type_any(). next_list() is
similar, but can't fail (see commit 08f9541). While all of them set
'*obj' to allocated storage on success, it was not obvious whether
'*obj' was guaranteed safe on failure, or whether it was left
uninitialized. But a future patch wants to guarantee that
visit_type_FOO() does not leak a partially-constructed obj back to
the caller; it is easier to implement this if we can reliably state
that input visitors assign '*obj' regardless of success or failure,
and that on failure *obj is NULL. Add assertions to enforce
consistency in the final setting of err vs. *obj.

The opts-visitor start_struct() doesn't set an error, but it
also was doing a weird check for 0 size; all callers pass in
non-zero size if obj is non-NULL.

The testsuite has at least one spot where we no longer need
to pre-initialize a variable prior to a visit; valgrind confirms
that the test is still fine with the cleanup.

A later patch will document the design constraint implemented
here.

Backports commit e58d695e6c3a5cfa0aa2fc91b87ade017ef28b05 from qemu
2018-02-23 14:53:23 -05:00

286 lines
7 KiB
C

/*
* Core Definitions for QAPI Visitor Classes
*
* Copyright (C) 2012-2016 Red Hat, Inc.
* 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/error.h"
#include "qemu-common.h"
#include "qapi/qmp/qobject.h"
#include "qapi/qmp/qerror.h"
#include "qapi/visitor.h"
#include "qapi/visitor-impl.h"
void visit_start_struct(Visitor *v, const char *name, void **obj,
size_t size, Error **errp)
{
Error *err = NULL;
v->start_struct(v, name, obj, size, &err);
if (obj && v->type == VISITOR_INPUT) {
assert(!err != !*obj);
}
error_propagate(errp, err);
}
void visit_end_struct(Visitor *v, Error **errp)
{
v->end_struct(v, errp);
}
void visit_start_implicit_struct(Visitor *v, void **obj, size_t size,
Error **errp)
{
if (v->start_implicit_struct) {
v->start_implicit_struct(v, obj, size, errp);
}
}
void visit_end_implicit_struct(Visitor *v)
{
if (v->end_implicit_struct) {
v->end_implicit_struct(v);
}
}
void visit_start_list(Visitor *v, const char *name, Error **errp)
{
v->start_list(v, name, errp);
}
GenericList *visit_next_list(Visitor *v, GenericList **list, size_t size)
{
assert(list && size >= sizeof(GenericList));
return v->next_list(v, list, size);
}
void visit_end_list(Visitor *v)
{
v->end_list(v);
}
bool visit_optional(Visitor *v, const char *name, bool *present)
{
if (v->optional) {
v->optional(v, name, present);
}
return *present;
}
void visit_get_next_type(Visitor *v, const char *name, QType *type,
bool promote_int, Error **errp)
{
if (v->get_next_type) {
v->get_next_type(v, name, type, promote_int, errp);
}
}
void visit_type_int(Visitor *v, const char *name, int64_t *obj, Error **errp)
{
v->type_int64(v, name, obj, errp);
}
static void visit_type_uintN(Visitor *v, const char *name, uint64_t *obj,
uint64_t max, const char *type, Error **errp)
{
Error *err = NULL;
uint64_t value = *obj;
v->type_uint64(v, name, &value, &err);
if (err) {
error_propagate(errp, err);
} else if (value > max) {
error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
name ? name : "null", type);
} else {
*obj = value;
}
}
void visit_type_uint8(Visitor *v, const char *name, uint8_t *obj, Error **errp)
{
uint64_t value = *obj;
visit_type_uintN(v, name, &value, UINT8_MAX, "uint8_t", errp);
*obj = value;
}
void visit_type_uint16(Visitor *v, const char *name, uint16_t *obj, Error **errp)
{
uint64_t value = *obj;
visit_type_uintN(v, name, &value, UINT16_MAX, "uint16_t", errp);
*obj = value;
}
void visit_type_uint32(Visitor *v, const char *name, uint32_t *obj, Error **errp)
{
uint64_t value = *obj;
visit_type_uintN(v, name, &value, UINT32_MAX, "uint32_t", errp);
*obj = value;
}
void visit_type_uint64(Visitor *v, const char *name, uint64_t *obj,
Error **errp)
{
v->type_uint64(v, name, obj, errp);
}
static void visit_type_intN(Visitor *v, const char *name, int64_t *obj,
int64_t min, int64_t max, const char *type,
Error **errp)
{
Error *err = NULL;
int64_t value = *obj;
v->type_int64(v, name, &value, &err);
if (err) {
error_propagate(errp, err);
} else if (value < min || value > max) {
error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
name ? name : "null", type);
} else {
*obj = value;
}
}
void visit_type_int8(Visitor *v, const char *name, int8_t *obj, Error **errp)
{
int64_t value = *obj;
visit_type_intN(v, name, &value, INT8_MIN, INT8_MAX, "int8_t", errp);
*obj = value;
}
void visit_type_int16(Visitor *v, const char *name, int16_t *obj,
Error **errp)
{
int64_t value = *obj;
visit_type_intN(v, name, &value, INT16_MIN, INT16_MAX, "int16_t", errp);
*obj = value;
}
void visit_type_int32(Visitor *v, const char *name, int32_t *obj,
Error **errp)
{
int64_t value = *obj;
visit_type_intN(v, name, &value, INT32_MIN, INT32_MAX, "int32_t", errp);
*obj = value;
}
void visit_type_int64(Visitor *v, const char *name, int64_t *obj,
Error **errp)
{
v->type_int64(v, name, obj, errp);
}
void visit_type_size(Visitor *v, const char *name, uint64_t *obj,
Error **errp)
{
if (v->type_size) {
v->type_size(v, name, obj, errp);
} else {
v->type_uint64(v, name, obj, errp);
}
}
void visit_type_bool(Visitor *v, const char *name, bool *obj, Error **errp)
{
v->type_bool(v, name, obj, errp);
}
void visit_type_str(Visitor *v, const char *name, char **obj, Error **errp)
{
Error *err = NULL;
assert(obj);
v->type_str(v, name, obj, &err);
if (v->type == VISITOR_INPUT) {
assert(!err != !*obj);
}
error_propagate(errp, err);
}
void visit_type_number(Visitor *v, const char *name, double *obj,
Error **errp)
{
v->type_number(v, name, obj, errp);
}
void visit_type_any(Visitor *v, const char *name, QObject **obj, Error **errp)
{
Error *err = NULL;
assert(obj);
v->type_any(v, name, obj, &err);
if (v->type == VISITOR_INPUT) {
assert(!err != !*obj);
}
error_propagate(errp, err);
}
static void output_type_enum(Visitor *v, const char *name, int *obj,
const char *const strings[], Error **errp)
{
int i = 0;
int value = *obj;
char *enum_str;
while (strings[i++] != NULL);
if (value < 0 || value >= i - 1) {
error_setg(errp, QERR_INVALID_PARAMETER, name ? name : "null");
return;
}
enum_str = (char *)strings[value];
visit_type_str(v, name, &enum_str, errp);
}
static void input_type_enum(Visitor *v, const char *name, int *obj,
const char *const strings[], Error **errp)
{
Error *local_err = NULL;
int64_t value = 0;
char *enum_str;
visit_type_str(v, name, &enum_str, &local_err);
if (local_err) {
error_propagate(errp, local_err);
return;
}
while (strings[value] != NULL) {
if (strcmp(strings[value], enum_str) == 0) {
break;
}
value++;
}
if (strings[value] == NULL) {
error_setg(errp, QERR_INVALID_PARAMETER, enum_str);
g_free(enum_str);
return;
}
g_free(enum_str);
*obj = (int)value;
}
void visit_type_enum(Visitor *v, const char *name, int *obj,
const char *const strings[], Error **errp)
{
assert(strings);
if (v->type == VISITOR_INPUT) {
input_type_enum(v, name, obj, strings, errp);
} else if (v->type == VISITOR_OUTPUT) {
output_type_enum(v, name, obj, strings, errp);
}
}