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qemu/qapi/qobject-input-visitor.c
Kevin Wolf 8bf12c4f75 keyval: Parse help options 
This adds a special meaning for 'help' and '?' as options to the keyval
parser. Instead of being an error (because of a missing value) or a
value for an implied key, they now request help, which is a new boolean
output of the parser in addition to the QDict.

A new parameter 'p_help' is added to keyval_parse() that contains on
return whether help was requested. If NULL is passed, requesting help
results in an error and all other cases work like before.

Turning previous error cases into help is a compatible extension. The
behaviour potentially changes for implied keys: They could previously
get 'help' as their value, which is now interpreted as requesting help.

This is not a problem in practice because 'help' and '?' are not a valid
values for the implied key of any option parsed with keyval_parse():

* audiodev: union Audiodev, implied key "driver" is enum AudiodevDriver,
  "help" and "?" are not among its values

* display: union DisplayOptions, implied key "type" is enum
  DisplayType, "help" and "?" are not among its values

* blockdev: union BlockdevOptions, implied key "driver is enum
  BlockdevDriver, "help" and "?" are not among its values

* export: union BlockExport, implied key "type" is enum BlockExportType,
  "help" and "?" are not among its values

* monitor: struct MonitorOptions, implied key "mode" is enum MonitorMode,
  "help" and "?" are not among its values

* nbd-server: struct NbdServerOptions, no implied key.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20201011073505.1185335-5-armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-10-15 16:06:27 +02:00

770 lines
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/*
* Input Visitor
*
* Copyright (C) 2012-2017 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 <math.h>
#include "qapi/error.h"
#include "qapi/qobject-input-visitor.h"
#include "qapi/visitor-impl.h"
#include "qemu/queue.h"
#include "qapi/qmp/qjson.h"
#include "qapi/qmp/qbool.h"
#include "qapi/qmp/qdict.h"
#include "qapi/qmp/qerror.h"
#include "qapi/qmp/qlist.h"
#include "qapi/qmp/qnull.h"
#include "qapi/qmp/qnum.h"
#include "qapi/qmp/qstring.h"
#include "qemu/cutils.h"
#include "qemu/option.h"
typedef struct StackObject {
const char *name; /* Name of @obj in its parent, if any */
QObject *obj; /* QDict or QList being visited */
void *qapi; /* sanity check that caller uses same pointer */
GHashTable *h; /* If @obj is QDict: unvisited keys */
const QListEntry *entry; /* If @obj is QList: unvisited tail */
unsigned index; /* If @obj is QList: list index of @entry */
QSLIST_ENTRY(StackObject) node; /* parent */
} StackObject;
struct QObjectInputVisitor {
Visitor visitor;
/* Root of visit at visitor creation. */
QObject *root;
bool keyval; /* Assume @root made with keyval_parse() */
/* Stack of objects being visited (all entries will be either
* QDict or QList). */
QSLIST_HEAD(, StackObject) stack;
GString *errname; /* Accumulator for full_name() */
};
static QObjectInputVisitor *to_qiv(Visitor *v)
{
return container_of(v, QObjectInputVisitor, visitor);
}
/*
* Find the full name of something @qiv is currently visiting.
* @qiv is visiting something named @name in the stack of containers
* @qiv->stack.
* If @n is zero, return its full name.
* If @n is positive, return the full name of the @n-th container
* counting from the top. The stack of containers must have at least
* @n elements.
* The returned string is valid until the next full_name_nth(@v) or
* destruction of @v.
*/
static const char *full_name_nth(QObjectInputVisitor *qiv, const char *name,
int n)
{
StackObject *so;
char buf[32];
if (qiv->errname) {
g_string_truncate(qiv->errname, 0);
} else {
qiv->errname = g_string_new("");
}
QSLIST_FOREACH(so , &qiv->stack, node) {
if (n) {
n--;
} else if (qobject_type(so->obj) == QTYPE_QDICT) {
g_string_prepend(qiv->errname, name ?: "<anonymous>");
g_string_prepend_c(qiv->errname, '.');
} else {
snprintf(buf, sizeof(buf),
qiv->keyval ? ".%u" : "[%u]",
so->index);
g_string_prepend(qiv->errname, buf);
}
name = so->name;
}
assert(!n);
if (name) {
g_string_prepend(qiv->errname, name);
} else if (qiv->errname->str[0] == '.') {
g_string_erase(qiv->errname, 0, 1);
} else if (!qiv->errname->str[0]) {
return "<anonymous>";
}
return qiv->errname->str;
}
static const char *full_name(QObjectInputVisitor *qiv, const char *name)
{
return full_name_nth(qiv, name, 0);
}
static QObject *qobject_input_try_get_object(QObjectInputVisitor *qiv,
const char *name,
bool consume)
{
StackObject *tos;
QObject *qobj;
QObject *ret;
if (QSLIST_EMPTY(&qiv->stack)) {
/* Starting at root, name is ignored. */
assert(qiv->root);
return qiv->root;
}
/* We are in a container; find the next element. */
tos = QSLIST_FIRST(&qiv->stack);
qobj = tos->obj;
assert(qobj);
if (qobject_type(qobj) == QTYPE_QDICT) {
assert(name);
ret = qdict_get(qobject_to(QDict, qobj), name);
if (tos->h && consume && ret) {
bool removed = g_hash_table_remove(tos->h, name);
assert(removed);
}
} else {
assert(qobject_type(qobj) == QTYPE_QLIST);
assert(!name);
if (tos->entry) {
ret = qlist_entry_obj(tos->entry);
if (consume) {
tos->entry = qlist_next(tos->entry);
}
} else {
ret = NULL;
}
if (consume) {
tos->index++;
}
}
return ret;
}
static QObject *qobject_input_get_object(QObjectInputVisitor *qiv,
const char *name,
bool consume, Error **errp)
{
QObject *obj = qobject_input_try_get_object(qiv, name, consume);
if (!obj) {
error_setg(errp, QERR_MISSING_PARAMETER, full_name(qiv, name));
}
return obj;
}
static const char *qobject_input_get_keyval(QObjectInputVisitor *qiv,
const char *name,
Error **errp)
{
QObject *qobj;
QString *qstr;
qobj = qobject_input_get_object(qiv, name, true, errp);
if (!qobj) {
return NULL;
}
qstr = qobject_to(QString, qobj);
if (!qstr) {
switch (qobject_type(qobj)) {
case QTYPE_QDICT:
case QTYPE_QLIST:
error_setg(errp, "Parameters '%s.*' are unexpected",
full_name(qiv, name));
return NULL;
default:
/* Non-string scalar (should this be an assertion?) */
error_setg(errp, "Internal error: parameter %s invalid",
full_name(qiv, name));
return NULL;
}
}
return qstring_get_str(qstr);
}
static const QListEntry *qobject_input_push(QObjectInputVisitor *qiv,
const char *name,
QObject *obj, void *qapi)
{
GHashTable *h;
StackObject *tos = g_new0(StackObject, 1);
QDict *qdict = qobject_to(QDict, obj);
QList *qlist = qobject_to(QList, obj);
const QDictEntry *entry;
assert(obj);
tos->name = name;
tos->obj = obj;
tos->qapi = qapi;
if (qdict) {
h = g_hash_table_new(g_str_hash, g_str_equal);
for (entry = qdict_first(qdict);
entry;
entry = qdict_next(qdict, entry)) {
g_hash_table_insert(h, (void *)qdict_entry_key(entry), NULL);
}
tos->h = h;
} else {
assert(qlist);
tos->entry = qlist_first(qlist);
tos->index = -1;
}
QSLIST_INSERT_HEAD(&qiv->stack, tos, node);
return tos->entry;
}
static bool qobject_input_check_struct(Visitor *v, Error **errp)
{
QObjectInputVisitor *qiv = to_qiv(v);
StackObject *tos = QSLIST_FIRST(&qiv->stack);
GHashTableIter iter;
const char *key;
assert(tos && !tos->entry);
g_hash_table_iter_init(&iter, tos->h);
if (g_hash_table_iter_next(&iter, (void **)&key, NULL)) {
error_setg(errp, "Parameter '%s' is unexpected",
full_name(qiv, key));
return false;
}
return true;
}
static void qobject_input_stack_object_free(StackObject *tos)
{
if (tos->h) {
g_hash_table_unref(tos->h);
}
g_free(tos);
}
static void qobject_input_pop(Visitor *v, void **obj)
{
QObjectInputVisitor *qiv = to_qiv(v);
StackObject *tos = QSLIST_FIRST(&qiv->stack);
assert(tos && tos->qapi == obj);
QSLIST_REMOVE_HEAD(&qiv->stack, node);
qobject_input_stack_object_free(tos);
}
static bool qobject_input_start_struct(Visitor *v, const char *name, void **obj,
size_t size, Error **errp)
{
QObjectInputVisitor *qiv = to_qiv(v);
QObject *qobj = qobject_input_get_object(qiv, name, true, errp);
if (obj) {
*obj = NULL;
}
if (!qobj) {
return false;
}
if (qobject_type(qobj) != QTYPE_QDICT) {
error_setg(errp, QERR_INVALID_PARAMETER_TYPE,
full_name(qiv, name), "object");
return false;
}
qobject_input_push(qiv, name, qobj, obj);
if (obj) {
*obj = g_malloc0(size);
}
return true;
}
static void qobject_input_end_struct(Visitor *v, void **obj)
{
QObjectInputVisitor *qiv = to_qiv(v);
StackObject *tos = QSLIST_FIRST(&qiv->stack);
assert(qobject_type(tos->obj) == QTYPE_QDICT && tos->h);
qobject_input_pop(v, obj);
}
static bool qobject_input_start_list(Visitor *v, const char *name,
GenericList **list, size_t size,
Error **errp)
{
QObjectInputVisitor *qiv = to_qiv(v);
QObject *qobj = qobject_input_get_object(qiv, name, true, errp);
const QListEntry *entry;
if (list) {
*list = NULL;
}
if (!qobj) {
return false;
}
if (qobject_type(qobj) != QTYPE_QLIST) {
error_setg(errp, QERR_INVALID_PARAMETER_TYPE,
full_name(qiv, name), "array");
return false;
}
entry = qobject_input_push(qiv, name, qobj, list);
if (entry && list) {
*list = g_malloc0(size);
}
return true;
}
static GenericList *qobject_input_next_list(Visitor *v, GenericList *tail,
size_t size)
{
QObjectInputVisitor *qiv = to_qiv(v);
StackObject *tos = QSLIST_FIRST(&qiv->stack);
assert(tos && qobject_to(QList, tos->obj));
if (!tos->entry) {
return NULL;
}
tail->next = g_malloc0(size);
return tail->next;
}
static bool qobject_input_check_list(Visitor *v, Error **errp)
{
QObjectInputVisitor *qiv = to_qiv(v);
StackObject *tos = QSLIST_FIRST(&qiv->stack);
assert(tos && qobject_to(QList, tos->obj));
if (tos->entry) {
error_setg(errp, "Only %u list elements expected in %s",
tos->index + 1, full_name_nth(qiv, NULL, 1));
return false;
}
return true;
}
static void qobject_input_end_list(Visitor *v, void **obj)
{
QObjectInputVisitor *qiv = to_qiv(v);
StackObject *tos = QSLIST_FIRST(&qiv->stack);
assert(qobject_type(tos->obj) == QTYPE_QLIST && !tos->h);
qobject_input_pop(v, obj);
}
static bool qobject_input_start_alternate(Visitor *v, const char *name,
GenericAlternate **obj, size_t size,
Error **errp)
{
QObjectInputVisitor *qiv = to_qiv(v);
QObject *qobj = qobject_input_get_object(qiv, name, false, errp);
if (!qobj) {
*obj = NULL;
return false;
}
*obj = g_malloc0(size);
(*obj)->type = qobject_type(qobj);
return true;
}
static bool qobject_input_type_int64(Visitor *v, const char *name, int64_t *obj,
Error **errp)
{
QObjectInputVisitor *qiv = to_qiv(v);
QObject *qobj = qobject_input_get_object(qiv, name, true, errp);
QNum *qnum;
if (!qobj) {
return false;
}
qnum = qobject_to(QNum, qobj);
if (!qnum || !qnum_get_try_int(qnum, obj)) {
error_setg(errp, QERR_INVALID_PARAMETER_TYPE,
full_name(qiv, name), "integer");
return false;
}
return true;
}
static bool qobject_input_type_int64_keyval(Visitor *v, const char *name,
int64_t *obj, Error **errp)
{
QObjectInputVisitor *qiv = to_qiv(v);
const char *str = qobject_input_get_keyval(qiv, name, errp);
if (!str) {
return false;
}
if (qemu_strtoi64(str, NULL, 0, obj) < 0) {
/* TODO report -ERANGE more nicely */
error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
full_name(qiv, name), "integer");
return false;
}
return true;
}
static bool qobject_input_type_uint64(Visitor *v, const char *name,
uint64_t *obj, Error **errp)
{
QObjectInputVisitor *qiv = to_qiv(v);
QObject *qobj = qobject_input_get_object(qiv, name, true, errp);
QNum *qnum;
int64_t val;
if (!qobj) {
return false;
}
qnum = qobject_to(QNum, qobj);
if (!qnum) {
goto err;
}
if (qnum_get_try_uint(qnum, obj)) {
return true;
}
/* Need to accept negative values for backward compatibility */
if (qnum_get_try_int(qnum, &val)) {
*obj = val;
return true;
}
err:
error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
full_name(qiv, name), "uint64");
return false;
}
static bool qobject_input_type_uint64_keyval(Visitor *v, const char *name,
uint64_t *obj, Error **errp)
{
QObjectInputVisitor *qiv = to_qiv(v);
const char *str = qobject_input_get_keyval(qiv, name, errp);
if (!str) {
return false;
}
if (qemu_strtou64(str, NULL, 0, obj) < 0) {
/* TODO report -ERANGE more nicely */
error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
full_name(qiv, name), "integer");
return false;
}
return true;
}
static bool qobject_input_type_bool(Visitor *v, const char *name, bool *obj,
Error **errp)
{
QObjectInputVisitor *qiv = to_qiv(v);
QObject *qobj = qobject_input_get_object(qiv, name, true, errp);
QBool *qbool;
if (!qobj) {
return false;
}
qbool = qobject_to(QBool, qobj);
if (!qbool) {
error_setg(errp, QERR_INVALID_PARAMETER_TYPE,
full_name(qiv, name), "boolean");
return false;
}
*obj = qbool_get_bool(qbool);
return true;
}
static bool qobject_input_type_bool_keyval(Visitor *v, const char *name,
bool *obj, Error **errp)
{
QObjectInputVisitor *qiv = to_qiv(v);
const char *str = qobject_input_get_keyval(qiv, name, errp);
if (!str) {
return false;
}
if (!strcmp(str, "on")) {
*obj = true;
} else if (!strcmp(str, "off")) {
*obj = false;
} else {
error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
full_name(qiv, name), "'on' or 'off'");
return false;
}
return true;
}
static bool qobject_input_type_str(Visitor *v, const char *name, char **obj,
Error **errp)
{
QObjectInputVisitor *qiv = to_qiv(v);
QObject *qobj = qobject_input_get_object(qiv, name, true, errp);
QString *qstr;
*obj = NULL;
if (!qobj) {
return false;
}
qstr = qobject_to(QString, qobj);
if (!qstr) {
error_setg(errp, QERR_INVALID_PARAMETER_TYPE,
full_name(qiv, name), "string");
return false;
}
*obj = g_strdup(qstring_get_str(qstr));
return true;
}
static bool qobject_input_type_str_keyval(Visitor *v, const char *name,
char **obj, Error **errp)
{
QObjectInputVisitor *qiv = to_qiv(v);
const char *str = qobject_input_get_keyval(qiv, name, errp);
*obj = g_strdup(str);
return !!str;
}
static bool qobject_input_type_number(Visitor *v, const char *name, double *obj,
Error **errp)
{
QObjectInputVisitor *qiv = to_qiv(v);
QObject *qobj = qobject_input_get_object(qiv, name, true, errp);
QNum *qnum;
if (!qobj) {
return false;
}
qnum = qobject_to(QNum, qobj);
if (!qnum) {
error_setg(errp, QERR_INVALID_PARAMETER_TYPE,
full_name(qiv, name), "number");
return false;
}
*obj = qnum_get_double(qnum);
return true;
}
static bool qobject_input_type_number_keyval(Visitor *v, const char *name,
double *obj, Error **errp)
{
QObjectInputVisitor *qiv = to_qiv(v);
const char *str = qobject_input_get_keyval(qiv, name, errp);
double val;
if (!str) {
return false;
}
if (qemu_strtod_finite(str, NULL, &val)) {
/* TODO report -ERANGE more nicely */
error_setg(errp, QERR_INVALID_PARAMETER_TYPE,
full_name(qiv, name), "number");
return false;
}
*obj = val;
return true;
}
static bool qobject_input_type_any(Visitor *v, const char *name, QObject **obj,
Error **errp)
{
QObjectInputVisitor *qiv = to_qiv(v);
QObject *qobj = qobject_input_get_object(qiv, name, true, errp);
*obj = NULL;
if (!qobj) {
return false;
}
*obj = qobject_ref(qobj);
return true;
}
static bool qobject_input_type_null(Visitor *v, const char *name,
QNull **obj, Error **errp)
{
QObjectInputVisitor *qiv = to_qiv(v);
QObject *qobj = qobject_input_get_object(qiv, name, true, errp);
*obj = NULL;
if (!qobj) {
return false;
}
if (qobject_type(qobj) != QTYPE_QNULL) {
error_setg(errp, QERR_INVALID_PARAMETER_TYPE,
full_name(qiv, name), "null");
return false;
}
*obj = qnull();
return true;
}
static bool qobject_input_type_size_keyval(Visitor *v, const char *name,
uint64_t *obj, Error **errp)
{
QObjectInputVisitor *qiv = to_qiv(v);
const char *str = qobject_input_get_keyval(qiv, name, errp);
if (!str) {
return false;
}
if (qemu_strtosz(str, NULL, obj) < 0) {
/* TODO report -ERANGE more nicely */
error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
full_name(qiv, name), "size");
return false;
}
return true;
}
static void qobject_input_optional(Visitor *v, const char *name, bool *present)
{
QObjectInputVisitor *qiv = to_qiv(v);
QObject *qobj = qobject_input_try_get_object(qiv, name, false);
if (!qobj) {
*present = false;
return;
}
*present = true;
}
static void qobject_input_free(Visitor *v)
{
QObjectInputVisitor *qiv = to_qiv(v);
while (!QSLIST_EMPTY(&qiv->stack)) {
StackObject *tos = QSLIST_FIRST(&qiv->stack);
QSLIST_REMOVE_HEAD(&qiv->stack, node);
qobject_input_stack_object_free(tos);
}
qobject_unref(qiv->root);
if (qiv->errname) {
g_string_free(qiv->errname, TRUE);
}
g_free(qiv);
}
static QObjectInputVisitor *qobject_input_visitor_base_new(QObject *obj)
{
QObjectInputVisitor *v = g_malloc0(sizeof(*v));
assert(obj);
v->visitor.type = VISITOR_INPUT;
v->visitor.start_struct = qobject_input_start_struct;
v->visitor.check_struct = qobject_input_check_struct;
v->visitor.end_struct = qobject_input_end_struct;
v->visitor.start_list = qobject_input_start_list;
v->visitor.next_list = qobject_input_next_list;
v->visitor.check_list = qobject_input_check_list;
v->visitor.end_list = qobject_input_end_list;
v->visitor.start_alternate = qobject_input_start_alternate;
v->visitor.optional = qobject_input_optional;
v->visitor.free = qobject_input_free;
v->root = qobject_ref(obj);
return v;
}
Visitor *qobject_input_visitor_new(QObject *obj)
{
QObjectInputVisitor *v = qobject_input_visitor_base_new(obj);
v->visitor.type_int64 = qobject_input_type_int64;
v->visitor.type_uint64 = qobject_input_type_uint64;
v->visitor.type_bool = qobject_input_type_bool;
v->visitor.type_str = qobject_input_type_str;
v->visitor.type_number = qobject_input_type_number;
v->visitor.type_any = qobject_input_type_any;
v->visitor.type_null = qobject_input_type_null;
return &v->visitor;
}
Visitor *qobject_input_visitor_new_keyval(QObject *obj)
{
QObjectInputVisitor *v = qobject_input_visitor_base_new(obj);
v->visitor.type_int64 = qobject_input_type_int64_keyval;
v->visitor.type_uint64 = qobject_input_type_uint64_keyval;
v->visitor.type_bool = qobject_input_type_bool_keyval;
v->visitor.type_str = qobject_input_type_str_keyval;
v->visitor.type_number = qobject_input_type_number_keyval;
v->visitor.type_any = qobject_input_type_any;
v->visitor.type_null = qobject_input_type_null;
v->visitor.type_size = qobject_input_type_size_keyval;
v->keyval = true;
return &v->visitor;
}
Visitor *qobject_input_visitor_new_str(const char *str,
const char *implied_key,
Error **errp)
{
bool is_json = str[0] == '{';
QObject *obj;
QDict *args;
Visitor *v;
if (is_json) {
obj = qobject_from_json(str, errp);
if (!obj) {
return NULL;
}
args = qobject_to(QDict, obj);
assert(args);
v = qobject_input_visitor_new(QOBJECT(args));
} else {
args = keyval_parse(str, implied_key, NULL, errp);
if (!args) {
return NULL;
}
v = qobject_input_visitor_new_keyval(QOBJECT(args));
}
qobject_unref(args);
return v;
}
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