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qapi: Make all visitors supply uint64 callbacks
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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>
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@ebblake
ebblake authored and Markus Armbruster committed Feb 8, 2016
1 parent 4c40314 commit f755dea
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Showing 7 changed files with 73 additions and 28 deletions.
9 changes: 6 additions & 3 deletions include/qapi/visitor-impl.h
View file
Expand Up @@ -40,6 +40,12 @@ struct Visitor
void (*type_int64)(Visitor *v, int64_t *obj, const char *name,
Error **errp);
/* Must be set. */
void (*type_uint64)(Visitor *v, uint64_t *obj, const char *name,
Error **errp);
/* Optional; fallback is type_uint64(). */
void (*type_size)(Visitor *v, uint64_t *obj, const char *name,
Error **errp);
/* Must be set. */
void (*type_bool)(Visitor *v, bool *obj, const char *name, Error **errp);
void (*type_str)(Visitor *v, char **obj, const char *name, Error **errp);
void (*type_number)(Visitor *v, double *obj, const char *name,
Expand All @@ -53,12 +59,9 @@ struct Visitor
void (*type_uint8)(Visitor *v, uint8_t *obj, const char *name, Error **errp);
void (*type_uint16)(Visitor *v, uint16_t *obj, const char *name, Error **errp);
void (*type_uint32)(Visitor *v, uint32_t *obj, const char *name, Error **errp);
void (*type_uint64)(Visitor *v, uint64_t *obj, const char *name, Error **errp);
void (*type_int8)(Visitor *v, int8_t *obj, const char *name, Error **errp);
void (*type_int16)(Visitor *v, int16_t *obj, const char *name, Error **errp);
void (*type_int32)(Visitor *v, int32_t *obj, const char *name, Error **errp);
/* visit_type_size() falls back to (*type_uint64)() if type_size is unset */
void (*type_size)(Visitor *v, uint64_t *obj, const char *name, Error **errp);
bool (*start_union)(Visitor *v, bool data_present, Error **errp);
};

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6 changes: 6 additions & 0 deletions qapi/qapi-dealloc-visitor.c
View file
Expand Up @@ -141,6 +141,11 @@ static void qapi_dealloc_type_int64(Visitor *v, int64_t *obj, const char *name,
{
}

static void qapi_dealloc_type_uint64(Visitor *v, uint64_t *obj,
const char *name, Error **errp)
{
}

static void qapi_dealloc_type_bool(Visitor *v, bool *obj, const char *name,
Error **errp)
{
Expand Down Expand Up @@ -216,6 +221,7 @@ QapiDeallocVisitor *qapi_dealloc_visitor_new(void)
v->visitor.end_list = qapi_dealloc_end_list;
v->visitor.type_enum = qapi_dealloc_type_enum;
v->visitor.type_int64 = qapi_dealloc_type_int64;
v->visitor.type_uint64 = qapi_dealloc_type_uint64;
v->visitor.type_bool = qapi_dealloc_type_bool;
v->visitor.type_str = qapi_dealloc_type_str;
v->visitor.type_number = qapi_dealloc_type_number;
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36 changes: 11 additions & 25 deletions qapi/qapi-visit-core.c
View file
Expand Up @@ -97,14 +97,14 @@ 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)
{
int64_t value;
uint64_t value;

if (v->type_uint8) {
v->type_uint8(v, obj, name, errp);
} else {
value = *obj;
v->type_int64(v, &value, name, errp);
if (value < 0 || value > UINT8_MAX) {
v->type_uint64(v, &value, name, errp);
if (value > UINT8_MAX) {
/* FIXME questionable reuse of errp if callback changed
value on error */
error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
Expand All @@ -117,14 +117,14 @@ 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)
{
int64_t value;
uint64_t value;

if (v->type_uint16) {
v->type_uint16(v, obj, name, errp);
} else {
value = *obj;
v->type_int64(v, &value, name, errp);
if (value < 0 || value > UINT16_MAX) {
v->type_uint64(v, &value, name, errp);
if (value > UINT16_MAX) {
/* FIXME questionable reuse of errp if callback changed
value on error */
error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
Expand All @@ -137,14 +137,14 @@ 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)
{
int64_t value;
uint64_t value;

if (v->type_uint32) {
v->type_uint32(v, obj, name, errp);
} else {
value = *obj;
v->type_int64(v, &value, name, errp);
if (value < 0 || value > UINT32_MAX) {
v->type_uint64(v, &value, name, errp);
if (value > UINT32_MAX) {
/* FIXME questionable reuse of errp if callback changed
value on error */
error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
Expand All @@ -157,15 +157,7 @@ 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)
{
int64_t value;

if (v->type_uint64) {
v->type_uint64(v, obj, name, errp);
} else {
value = *obj;
v->type_int64(v, &value, name, errp);
*obj = value;
}
v->type_uint64(v, obj, name, errp);
}

void visit_type_int8(Visitor *v, int8_t *obj, const char *name, Error **errp)
Expand Down Expand Up @@ -235,16 +227,10 @@ 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)
{
int64_t value;

if (v->type_size) {
v->type_size(v, obj, name, errp);
} else if (v->type_uint64) {
v->type_uint64(v, obj, name, errp);
} else {
value = *obj;
v->type_int64(v, &value, name, errp);
*obj = value;
v->type_uint64(v, obj, name, errp);
}
}

Expand Down
17 changes: 17 additions & 0 deletions qapi/qmp-input-visitor.c
View file
Expand Up @@ -240,6 +240,22 @@ static void qmp_input_type_int64(Visitor *v, int64_t *obj, const char *name,
*obj = qint_get_int(qint);
}

static void qmp_input_type_uint64(Visitor *v, uint64_t *obj, const char *name,
Error **errp)
{
/* FIXME: qobject_to_qint mishandles values over INT64_MAX */
QmpInputVisitor *qiv = to_qiv(v);
QInt *qint = qobject_to_qint(qmp_input_get_object(qiv, name, true));

if (!qint) {
error_setg(errp, QERR_INVALID_PARAMETER_TYPE, name ? name : "null",
"integer");
return;
}

*obj = qint_get_int(qint);
}

static void qmp_input_type_bool(Visitor *v, bool *obj, const char *name,
Error **errp)
{
Expand Down Expand Up @@ -343,6 +359,7 @@ QmpInputVisitor *qmp_input_visitor_new(QObject *obj)
v->visitor.end_list = qmp_input_end_list;
v->visitor.type_enum = input_type_enum;
v->visitor.type_int64 = qmp_input_type_int64;
v->visitor.type_uint64 = qmp_input_type_uint64;
v->visitor.type_bool = qmp_input_type_bool;
v->visitor.type_str = qmp_input_type_str;
v->visitor.type_number = qmp_input_type_number;
Expand Down
9 changes: 9 additions & 0 deletions qapi/qmp-output-visitor.c
View file
Expand Up @@ -166,6 +166,14 @@ static void qmp_output_type_int64(Visitor *v, int64_t *obj, const char *name,
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)
{
Expand Down Expand Up @@ -243,6 +251,7 @@ QmpOutputVisitor *qmp_output_visitor_new(void)
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;
Expand Down
15 changes: 15 additions & 0 deletions qapi/string-input-visitor.c
View file
Expand Up @@ -227,6 +227,20 @@ static void parse_type_int64(Visitor *v, int64_t *obj, const char *name,
"an int64 value or range");
}

static void parse_type_uint64(Visitor *v, uint64_t *obj, const char *name,
Error **errp)
{
/* FIXME: parse_type_int64 mishandles values over INT64_MAX */
int64_t i;
Error *err = NULL;
parse_type_int64(v, &i, name, &err);
if (err) {
error_propagate(errp, err);
} else {
*obj = i;
}
}

static void parse_type_size(Visitor *v, uint64_t *obj, const char *name,
Error **errp)
{
Expand Down Expand Up @@ -337,6 +351,7 @@ StringInputVisitor *string_input_visitor_new(const char *str)

v->visitor.type_enum = input_type_enum;
v->visitor.type_int64 = parse_type_int64;
v->visitor.type_uint64 = parse_type_uint64;
v->visitor.type_size = parse_type_size;
v->visitor.type_bool = parse_type_bool;
v->visitor.type_str = parse_type_str;
Expand Down
9 changes: 9 additions & 0 deletions qapi/string-output-visitor.c
View file
Expand Up @@ -198,6 +198,14 @@ static void print_type_int64(Visitor *v, int64_t *obj, const char *name,
}
}

static void print_type_uint64(Visitor *v, uint64_t *obj, const char *name,
Error **errp)
{
/* FIXME: print_type_int64 mishandles values over INT64_MAX */
int64_t i = *obj;
print_type_int64(v, &i, name, errp);
}

static void print_type_size(Visitor *v, uint64_t *obj, const char *name,
Error **errp)
{
Expand Down Expand Up @@ -347,6 +355,7 @@ StringOutputVisitor *string_output_visitor_new(bool human)
v->human = human;
v->visitor.type_enum = output_type_enum;
v->visitor.type_int64 = print_type_int64;
v->visitor.type_uint64 = print_type_uint64;
v->visitor.type_size = print_type_size;
v->visitor.type_bool = print_type_bool;
v->visitor.type_str = print_type_str;
Expand Down

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