/*
* Special QDict functions used by the block layer
*
* Copyright (c) 2013-2018 Red Hat, Inc.
*
* 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 "block/qdict.h"
#include "qapi/qmp/qbool.h"
#include "qapi/qmp/qlist.h"
#include "qapi/qmp/qnum.h"
#include "qapi/qmp/qstring.h"
#include "qapi/qobject-input-visitor.h"
#include "qemu/cutils.h"
#include "qapi/error.h"
/**
* qdict_copy_default(): If no entry mapped by 'key' exists in 'dst' yet, the
* value of 'key' in 'src' is copied there (and the refcount increased
* accordingly).
*/
void qdict_copy_default(QDict *dst, QDict *src, const char *key)
{
QObject *val;
if (qdict_haskey(dst, key)) {
return;
}
val = qdict_get(src, key);
if (val) {
qdict_put_obj(dst, key, qobject_ref(val));
}
}
/**
* qdict_set_default_str(): If no entry mapped by 'key' exists in 'dst' yet, a
* new QString initialised by 'val' is put there.
*/
void qdict_set_default_str(QDict *dst, const char *key, const char *val)
{
if (qdict_haskey(dst, key)) {
return;
}
qdict_put_str(dst, key, val);
}
static void qdict_flatten_qdict(QDict *qdict, QDict *target,
const char *prefix);
static void qdict_flatten_qlist(QList *qlist, QDict *target, const char *prefix)
{
QObject *value;
const QListEntry *entry;
QDict *dict_val;
QList *list_val;
char *new_key;
int i;
/* This function is never called with prefix == NULL, i.e., it is always
* called from within qdict_flatten_q(list|dict)(). Therefore, it does not
* need to remove list entries during the iteration (the whole list will be
* deleted eventually anyway from qdict_flatten_qdict()). */
assert(prefix);
entry = qlist_first(qlist);
for (i = 0; entry; entry = qlist_next(entry), i++) {
value = qlist_entry_obj(entry);
dict_val = qobject_to(QDict, value);
list_val = qobject_to(QList, value);
new_key = g_strdup_printf("%s.%i", prefix, i);
/*
* Flatten non-empty QDict and QList recursively into @target,
* copy other objects to @target
*/
if (dict_val && qdict_size(dict_val)) {
qdict_flatten_qdict(dict_val, target, new_key);
} else if (list_val && !qlist_empty(list_val)) {
qdict_flatten_qlist(list_val, target, new_key);
} else {
qdict_put_obj(target, new_key, qobject_ref(value));
}
g_free(new_key);
}
}
static void qdict_flatten_qdict(QDict *qdict, QDict *target, const char *prefix)
{
QObject *value;
const QDictEntry *entry, *next;
QDict *dict_val;
QList *list_val;
char *key, *new_key;
entry = qdict_first(qdict);
while (entry != NULL) {
next = qdict_next(qdict, entry);
value = qdict_entry_value(entry);
dict_val = qobject_to(QDict, value);
list_val = qobject_to(QList, value);
if (prefix) {
key = new_key = g_strdup_printf("%s.%s", prefix, entry->key);
} else {
key = entry->key;
new_key = NULL;
}
/*
* Flatten non-empty QDict and QList recursively into @target,
* copy other objects to @target.
* On the root level (if @qdict == @target), remove flattened
* nested QDicts and QLists from @qdict.
*
* (Note that we do not need to remove entries from nested
* dicts or lists. Their reference count is decremented on
* the root level, so there are no leaks. In fact, if they
* have a reference count greater than one, we are probably
* well advised not to modify them altogether.)
*/
if (dict_val && qdict_size(dict_val)) {
qdict_flatten_qdict(dict_val, target, key);
if (target == qdict) {
qdict_del(qdict, entry->key);
}
} else if (list_val && !qlist_empty(list_val)) {
qdict_flatten_qlist(list_val, target, key);
if (target == qdict) {
qdict_del(qdict, entry->key);
}
} else if (target != qdict) {
qdict_put_obj(target, key, qobject_ref(value));
}
g_free(new_key);
entry = next;
}
}
/**
* qdict_flatten(): For each nested non-empty QDict with key x, all
* fields with key y are moved to this QDict and their key is renamed
* to "x.y". For each nested non-empty QList with key x, the field at
* index y is moved to this QDict with the key "x.y" (i.e., the
* reverse of what qdict_array_split() does).
* This operation is applied recursively for nested QDicts and QLists.
*/
void qdict_flatten(QDict *qdict)
{
qdict_flatten_qdict(qdict, qdict, NULL);
}
/* extract all the src QDict entries starting by start into dst.
* If dst is NULL then the entries are simply removed from src. */
void qdict_extract_subqdict(QDict *src, QDict **dst, const char *start)
{
const QDictEntry *entry, *next;
const char *p;
if (dst) {
*dst = qdict_new();
}
entry = qdict_first(src);
while (entry != NULL) {
next = qdict_next(src, entry);
if (strstart(entry->key, start, &p)) {
if (dst) {
qdict_put_obj(*dst, p, qobject_ref(entry->value));
}
qdict_del(src, entry->key);
}
entry = next;
}
}
static int qdict_count_prefixed_entries(const QDict *src, const char *start)
{
const QDictEntry *entry;
int count = 0;
for (entry = qdict_first(src); entry; entry = qdict_next(src, entry)) {
if (strstart(entry->key, start, NULL)) {
if (count == INT_MAX) {
return -ERANGE;
}
count++;
}
}
return count;
}
/**
* qdict_array_split(): This function moves array-like elements of a QDict into
* a new QList. Every entry in the original QDict with a key "%u" or one
* prefixed "%u.", where %u designates an unsigned integer starting at 0 and
* incrementally counting up, will be moved to a new QDict at index %u in the
* output QList with the key prefix removed, if that prefix is "%u.". If the
* whole key is just "%u", the whole QObject will be moved unchanged without
* creating a new QDict. The function terminates when there is no entry in the
* QDict with a prefix directly (incrementally) following the last one; it also
* returns if there are both entries with "%u" and "%u." for the same index %u.
* Example: {"0.a": 42, "0.b": 23, "1.x": 0, "4.y": 1, "o.o": 7, "2": 66}
* (or {"1.x": 0, "4.y": 1, "0.a": 42, "o.o": 7, "0.b": 23, "2": 66})
* => [{"a": 42, "b": 23}, {"x": 0}, 66]
* and {"4.y": 1, "o.o": 7} (remainder of the old QDict)
*/
void qdict_array_split(QDict *src, QList **dst)
{
unsigned i;
*dst = qlist_new();
for (i = 0; i < UINT_MAX; i++) {
QObject *subqobj;
bool is_subqdict;
QDict *subqdict;
char indexstr[32], prefix[32];
size_t snprintf_ret;
snprintf_ret = snprintf(indexstr, 32, "%u", i);
assert(snprintf_ret < 32);
subqobj = qdict_get(src, indexstr);
snprintf_ret = snprintf(prefix, 32, "%u.", i);
assert(snprintf_ret < 32);
/* Overflow is the same as positive non-zero results */
is_subqdict = qdict_count_prefixed_entries(src, prefix);
/*
* There may be either a single subordinate object (named
* "%u") or multiple objects (each with a key prefixed "%u."),
* but not both.
*/
if (!subqobj == !is_subqdict) {
break;
}
if (is_subqdict) {
qdict_extract_subqdict(src, &subqdict, prefix);
assert(qdict_size(subqdict) > 0);
qlist_append_obj(*dst, QOBJECT(subqdict));
} else {
qobject_ref(subqobj);
qdict_del(src, indexstr);
qlist_append_obj(*dst, subqobj);
}
}
}
/**
* qdict_split_flat_key:
* @key: the key string to split
* @prefix: non-NULL pointer to hold extracted prefix
* @suffix: non-NULL pointer to remaining suffix
*
* Given a flattened key such as 'foo.0.bar', split it into two parts
* at the first '.' separator. Allows double dot ('..') to escape the
* normal separator.
*
* e.g.
* 'foo.0.bar' -> prefix='foo' and suffix='0.bar'
* 'foo..0.bar' -> prefix='foo.0' and suffix='bar'
*
* The '..' sequence will be unescaped in the returned 'prefix'
* string. The 'suffix' string will be left in escaped format, so it
* can be fed back into the qdict_split_flat_key() key as the input
* later.
*
* The caller is responsible for freeing the string returned in @prefix
* using g_free().
*/
static void qdict_split_flat_key(const char *key, char **prefix,
const char **suffix)
{
const char *separator;
size_t i, j;
/* Find first '.' separator, but if there is a pair '..'
* that acts as an escape, so skip over '..' */
separator = NULL;
do {
if (separator) {
separator += 2;
} else {
separator = key;
}
separator = strchr(separator, '.');
} while (separator && separator[1] == '.');
if (separator) {
*prefix = g_strndup(key, separator - key);
*suffix = separator + 1;
} else {
*prefix = g_strdup(key);
*suffix = NULL;
}
/* Unescape the '..' sequence into '.' */
for (i = 0, j = 0; (*prefix)[i] != '\0'; i++, j++) {
if ((*prefix)[i] == '.') {
assert((*prefix)[i + 1] == '.');
i++;
}
(*prefix)[j] = (*prefix)[i];
}
(*prefix)[j] = '\0';
}
/**
* qdict_is_list:
* @maybe_list: dict to check if keys represent list elements.
*
* Determine whether all keys in @maybe_list are valid list elements.
* If @maybe_list is non-zero in length and all the keys look like
* valid list indexes, this will return 1. If @maybe_list is zero
* length or all keys are non-numeric then it will return 0 to indicate
* it is a normal qdict. If there is a mix of numeric and non-numeric
* keys, or the list indexes are non-contiguous, an error is reported.
*
* Returns: 1 if a valid list, 0 if a dict, -1 on error
*/
static int qdict_is_list(QDict *maybe_list, Error **errp)
{
const QDictEntry *ent;
ssize_t len = 0;
ssize_t max = -1;
int is_list = -1;
int64_t val;
for (ent = qdict_first(maybe_list); ent != NULL;
ent = qdict_next(maybe_list, ent)) {
int is_index = !qemu_strtoi64(ent->key, NULL, 10, &val);
if (is_list == -1) {
is_list = is_index;
}
if (is_index != is_list) {
error_setg(errp, "Cannot mix list and non-list keys");
return -1;
}
if (is_index) {
len++;
if (val > max) {
max = val;
}
}
}
if (is_list == -1) {
assert(!qdict_size(maybe_list));
is_list = 0;
}
/* NB this isn't a perfect check - e.g. it won't catch
* a list containing '1', '+1', '01', '3', but that
* does not matter - we've still proved that the
* input is a list. It is up the caller to do a
* stricter check if desired */
if (len != (max + 1)) {
error_setg(errp, "List indices are not contiguous, "
"saw %zd elements but %zd largest index",
len, max);
return -1;
}
return is_list;
}
/**
* qdict_crumple:
* @src: the original flat dictionary (only scalar values) to crumple
*
* Takes a flat dictionary whose keys use '.' separator to indicate
* nesting, and values are scalars, empty dictionaries or empty lists,
* and crumples it into a nested structure.
*
* To include a literal '.' in a key name, it must be escaped as '..'
*
* For example, an input of:
*
* { 'foo.0.bar': 'one', 'foo.0.wizz': '1',
* 'foo.1.bar': 'two', 'foo.1.wizz': '2' }
*
* will result in an output of:
*
* {
* 'foo': [
* { 'bar': 'one', 'wizz': '1' },
* { 'bar': 'two', 'wizz': '2' }
* ],
* }
*
* The following scenarios in the input dict will result in an
* error being returned:
*
* - Any values in @src are non-scalar types
* - If keys in @src imply that a particular level is both a
* list and a dict. e.g., "foo.0.bar" and "foo.eek.bar".
* - If keys in @src imply that a particular level is a list,
* but the indices are non-contiguous. e.g. "foo.0.bar" and
* "foo.2.bar" without any "foo.1.bar" present.
* - If keys in @src represent list indexes, but are not in
* the "%zu" format. e.g. "foo.+0.bar"
*
* Returns: either a QDict or QList for the nested data structure, or NULL
* on error
*/
QObject *qdict_crumple(const QDict *src, Error **errp)
{
const QDictEntry *ent;
QDict *two_level, *multi_level = NULL, *child_dict;
QDict *dict_val;
QList *list_val;
QObject *dst = NULL, *child;
size_t i;
char *prefix = NULL;
const char *suffix = NULL;
int is_list;
two_level = qdict_new();
/* Step 1: split our totally flat dict into a two level dict */
for (ent = qdict_first(src); ent != NULL; ent = qdict_next(src, ent)) {
dict_val = qobject_to(QDict, ent->value);
list_val = qobject_to(QList, ent->value);
if ((dict_val && qdict_size(dict_val))
|| (list_val && !qlist_empty(list_val))) {
error_setg(errp, "Value %s is not flat", ent->key);
goto error;
}
qdict_split_flat_key(ent->key, &prefix, &suffix);
child = qdict_get(two_level, prefix);
child_dict = qobject_to(QDict, child);
if (child) {
/*
* If @child_dict, then all previous keys with this prefix
* had a suffix. If @suffix, this one has one as well,
* and we're good, else there's a clash.
*/
if (!child_dict || !suffix) {
error_setg(errp, "Cannot mix scalar and non-scalar keys");
goto error;
}
}
if (suffix) {
if (!child_dict) {
child_dict = qdict_new();
qdict_put(two_level, prefix, child_dict);
}
qdict_put_obj(child_dict, suffix, qobject_ref(ent->value));
} else {
qdict_put_obj(two_level, prefix, qobject_ref(ent->value));
}
g_free(prefix);
prefix = NULL;
}
/* Step 2: optionally process the two level dict recursively
* into a multi-level dict */
multi_level = qdict_new();
for (ent = qdict_first(two_level); ent != NULL;
ent = qdict_next(two_level, ent)) {
dict_val = qobject_to(QDict, ent->value);
if (dict_val && qdict_size(dict_val)) {
child = qdict_crumple(dict_val, errp);
if (!child) {
goto error;
}
qdict_put_obj(multi_level, ent->key, child);
} else {
qdict_put_obj(multi_level, ent->key, qobject_ref(ent->value));
}
}
qobject_unref(two_level);
two_level = NULL;
/* Step 3: detect if we need to turn our dict into list */
is_list = qdict_is_list(multi_level, errp);
if (is_list < 0) {
goto error;
}
if (is_list) {
dst = QOBJECT(qlist_new());
for (i = 0; i < qdict_size(multi_level); i++) {
char *key = g_strdup_printf("%zu", i);
child = qdict_get(multi_level, key);
g_free(key);
if (!child) {
error_setg(errp, "Missing list index %zu", i);
goto error;
}
qlist_append_obj(qobject_to(QList, dst), qobject_ref(child));
}
qobject_unref(multi_level);
multi_level = NULL;
} else {
dst = QOBJECT(multi_level);
}
return dst;
error:
g_free(prefix);
qobject_unref(multi_level);
qobject_unref(two_level);
qobject_unref(dst);
return NULL;
}
/**
* qdict_crumple_for_keyval_qiv:
* @src: the flat dictionary (only scalar values) to crumple
* @errp: location to store error
*
* Like qdict_crumple(), but additionally transforms scalar values so
* the result can be passed to qobject_input_visitor_new_keyval().
*
* The block subsystem uses this function to prepare its flat QDict
* with possibly confused scalar types for a visit. It should not be
* used for anything else, and it should go away once the block
* subsystem has been cleaned up.
*/
static QObject *qdict_crumple_for_keyval_qiv(QDict *src, Error **errp)
{
QDict *tmp = NULL;
char *buf;
const char *s;
const QDictEntry *ent;
QObject *dst;
for (ent = qdict_first(src); ent; ent = qdict_next(src, ent)) {
buf = NULL;
switch (qobject_type(ent->value)) {
case QTYPE_QNULL:
case QTYPE_QSTRING:
continue;
case QTYPE_QNUM:
s = buf = qnum_to_string(qobject_to(QNum, ent->value));
break;
case QTYPE_QDICT:
case QTYPE_QLIST:
/* @src isn't flat; qdict_crumple() will fail */
continue;
case QTYPE_QBOOL:
s = qbool_get_bool(qobject_to(QBool, ent->value))
? "on" : "off";
break;
default:
abort();
}
if (!tmp) {
tmp = qdict_clone_shallow(src);
}
qdict_put_str(tmp, ent->key, s);
g_free(buf);
}
dst = qdict_crumple(tmp ?: src, errp);
qobject_unref(tmp);
return dst;
}
/**
* qdict_array_entries(): Returns the number of direct array entries if the
* sub-QDict of src specified by the prefix in subqdict (or src itself for
* prefix == "") is valid as an array, i.e. the length of the created list if
* the sub-QDict would become empty after calling qdict_array_split() on it. If
* the array is not valid, -EINVAL is returned.
*/
int qdict_array_entries(QDict *src, const char *subqdict)
{
const QDictEntry *entry;
unsigned i;
unsigned entries = 0;
size_t subqdict_len = strlen(subqdict);
assert(!subqdict_len || subqdict[subqdict_len - 1] == '.');
/* qdict_array_split() loops until UINT_MAX, but as we want to return
* negative errors, we only have a signed return value here. Any additional
* entries will lead to -EINVAL. */
for (i = 0; i < INT_MAX; i++) {
QObject *subqobj;
int subqdict_entries;
char *prefix = g_strdup_printf("%s%u.", subqdict, i);
subqdict_entries = qdict_count_prefixed_entries(src, prefix);
/* Remove ending "." */
prefix[strlen(prefix) - 1] = 0;
subqobj = qdict_get(src, prefix);
g_free(prefix);
if (subqdict_entries < 0) {
return subqdict_entries;
}
/* There may be either a single subordinate object (named "%u") or
* multiple objects (each with a key prefixed "%u."), but not both. */
if (subqobj && subqdict_entries) {
return -EINVAL;
} else if (!subqobj && !subqdict_entries) {
break;
}
entries += subqdict_entries ? subqdict_entries : 1;
}
/* Consider everything handled that isn't part of the given sub-QDict */
for (entry = qdict_first(src); entry; entry = qdict_next(src, entry)) {
if (!strstart(qdict_entry_key(entry), subqdict, NULL)) {
entries++;
}
}
/* Anything left in the sub-QDict that wasn't handled? */
if (qdict_size(src) != entries) {
return -EINVAL;
}
return i;
}
/**
* qdict_join(): Absorb the src QDict into the dest QDict, that is, move all
* elements from src to dest.
*
* If an element from src has a key already present in dest, it will not be
* moved unless overwrite is true.
*
* If overwrite is true, the conflicting values in dest will be discarded and
* replaced by the corresponding values from src.
*
* Therefore, with overwrite being true, the src QDict will always be empty when
* this function returns. If overwrite is false, the src QDict will be empty
* iff there were no conflicts.
*/
void qdict_join(QDict *dest, QDict *src, bool overwrite)
{
const QDictEntry *entry, *next;
entry = qdict_first(src);
while (entry) {
next = qdict_next(src, entry);
if (overwrite || !qdict_haskey(dest, entry->key)) {
qdict_put_obj(dest, entry->key, qobject_ref(entry->value));
qdict_del(src, entry->key);
}
entry = next;
}
}
/**
* qdict_rename_keys(): Rename keys in qdict according to the replacements
* specified in the array renames. The array must be terminated by an entry
* with from = NULL.
*
* The renames are performed individually in the order of the array, so entries
* may be renamed multiple times and may or may not conflict depending on the
* order of the renames array.
*
* Returns true for success, false in error cases.
*/
bool qdict_rename_keys(QDict *qdict, const QDictRenames *renames, Error **errp)
{
QObject *qobj;
while (renames->from) {
if (qdict_haskey(qdict, renames->from)) {
if (qdict_haskey(qdict, renames->to)) {
error_setg(errp, "'%s' and its alias '%s' can't be used at the "
"same time", renames->to, renames->from);
return false;
}
qobj = qdict_get(qdict, renames->from);
qdict_put_obj(qdict, renames->to, qobject_ref(qobj));
qdict_del(qdict, renames->from);
}
renames++;
}
return true;
}
/*
* Create a QObject input visitor for flat @qdict with possibly
* confused scalar types.
*
* The block subsystem uses this function to visit its flat QDict with
* possibly confused scalar types. It should not be used for anything
* else, and it should go away once the block subsystem has been
* cleaned up.
*/
Visitor *qobject_input_visitor_new_flat_confused(QDict *qdict,
Error **errp)
{
QObject *crumpled;
Visitor *v;
crumpled = qdict_crumple_for_keyval_qiv(qdict, errp);
if (!crumpled) {
return NULL;
}
v = qobject_input_visitor_new_keyval(crumpled);
qobject_unref(crumpled);
return v;
}
