qemu/qobject/qdict.c
Peter Xu de4905f4bc qdict: fix unbounded stack warning for qdict_array_entries
Here we use one g_strdup_printf() to replace the two stack allocated
array, considering it's more convenient, safe, and as long as it's
called rarely only when quorum device opens. This will remove the
unbound stack warning when compiling with "-Wstack-usage=1000000".

Reviewed-by:   Eric Blake <eblake@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
2016-05-18 15:04:26 +03:00

779 lines
20 KiB
C

/*
* QDict Module
*
* Copyright (C) 2009 Red Hat Inc.
*
* Authors:
* Luiz Capitulino <lcapitulino@redhat.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/qmp/qint.h"
#include "qapi/qmp/qfloat.h"
#include "qapi/qmp/qdict.h"
#include "qapi/qmp/qbool.h"
#include "qapi/qmp/qstring.h"
#include "qapi/qmp/qobject.h"
#include "qemu/queue.h"
#include "qemu-common.h"
#include "qemu/cutils.h"
/**
* qdict_new(): Create a new QDict
*
* Return strong reference.
*/
QDict *qdict_new(void)
{
QDict *qdict;
qdict = g_malloc0(sizeof(*qdict));
qobject_init(QOBJECT(qdict), QTYPE_QDICT);
return qdict;
}
/**
* qobject_to_qdict(): Convert a QObject into a QDict
*/
QDict *qobject_to_qdict(const QObject *obj)
{
if (!obj || qobject_type(obj) != QTYPE_QDICT) {
return NULL;
}
return container_of(obj, QDict, base);
}
/**
* tdb_hash(): based on the hash agorithm from gdbm, via tdb
* (from module-init-tools)
*/
static unsigned int tdb_hash(const char *name)
{
unsigned value; /* Used to compute the hash value. */
unsigned i; /* Used to cycle through random values. */
/* Set the initial value from the key size. */
for (value = 0x238F13AF * strlen(name), i=0; name[i]; i++)
value = (value + (((const unsigned char *)name)[i] << (i*5 % 24)));
return (1103515243 * value + 12345);
}
/**
* alloc_entry(): allocate a new QDictEntry
*/
static QDictEntry *alloc_entry(const char *key, QObject *value)
{
QDictEntry *entry;
entry = g_malloc0(sizeof(*entry));
entry->key = g_strdup(key);
entry->value = value;
return entry;
}
/**
* qdict_entry_value(): Return qdict entry value
*
* Return weak reference.
*/
QObject *qdict_entry_value(const QDictEntry *entry)
{
return entry->value;
}
/**
* qdict_entry_key(): Return qdict entry key
*
* Return a *pointer* to the string, it has to be duplicated before being
* stored.
*/
const char *qdict_entry_key(const QDictEntry *entry)
{
return entry->key;
}
/**
* qdict_find(): List lookup function
*/
static QDictEntry *qdict_find(const QDict *qdict,
const char *key, unsigned int bucket)
{
QDictEntry *entry;
QLIST_FOREACH(entry, &qdict->table[bucket], next)
if (!strcmp(entry->key, key))
return entry;
return NULL;
}
/**
* qdict_put_obj(): Put a new QObject into the dictionary
*
* Insert the pair 'key:value' into 'qdict', if 'key' already exists
* its 'value' will be replaced.
*
* This is done by freeing the reference to the stored QObject and
* storing the new one in the same entry.
*
* NOTE: ownership of 'value' is transferred to the QDict
*/
void qdict_put_obj(QDict *qdict, const char *key, QObject *value)
{
unsigned int bucket;
QDictEntry *entry;
bucket = tdb_hash(key) % QDICT_BUCKET_MAX;
entry = qdict_find(qdict, key, bucket);
if (entry) {
/* replace key's value */
qobject_decref(entry->value);
entry->value = value;
} else {
/* allocate a new entry */
entry = alloc_entry(key, value);
QLIST_INSERT_HEAD(&qdict->table[bucket], entry, next);
qdict->size++;
}
}
/**
* qdict_get(): Lookup for a given 'key'
*
* Return a weak reference to the QObject associated with 'key' if
* 'key' is present in the dictionary, NULL otherwise.
*/
QObject *qdict_get(const QDict *qdict, const char *key)
{
QDictEntry *entry;
entry = qdict_find(qdict, key, tdb_hash(key) % QDICT_BUCKET_MAX);
return (entry == NULL ? NULL : entry->value);
}
/**
* qdict_haskey(): Check if 'key' exists
*
* Return 1 if 'key' exists in the dict, 0 otherwise
*/
int qdict_haskey(const QDict *qdict, const char *key)
{
unsigned int bucket = tdb_hash(key) % QDICT_BUCKET_MAX;
return (qdict_find(qdict, key, bucket) == NULL ? 0 : 1);
}
/**
* qdict_size(): Return the size of the dictionary
*/
size_t qdict_size(const QDict *qdict)
{
return qdict->size;
}
/**
* qdict_get_obj(): Get a QObject of a specific type
*/
static QObject *qdict_get_obj(const QDict *qdict, const char *key, QType type)
{
QObject *obj;
obj = qdict_get(qdict, key);
assert(obj != NULL);
assert(qobject_type(obj) == type);
return obj;
}
/**
* qdict_get_double(): Get an number mapped by 'key'
*
* This function assumes that 'key' exists and it stores a
* QFloat or QInt object.
*
* Return number mapped by 'key'.
*/
double qdict_get_double(const QDict *qdict, const char *key)
{
QObject *obj = qdict_get(qdict, key);
assert(obj);
switch (qobject_type(obj)) {
case QTYPE_QFLOAT:
return qfloat_get_double(qobject_to_qfloat(obj));
case QTYPE_QINT:
return qint_get_int(qobject_to_qint(obj));
default:
abort();
}
}
/**
* qdict_get_int(): Get an integer mapped by 'key'
*
* This function assumes that 'key' exists and it stores a
* QInt object.
*
* Return integer mapped by 'key'.
*/
int64_t qdict_get_int(const QDict *qdict, const char *key)
{
return qint_get_int(qobject_to_qint(qdict_get(qdict, key)));
}
/**
* qdict_get_bool(): Get a bool mapped by 'key'
*
* This function assumes that 'key' exists and it stores a
* QBool object.
*
* Return bool mapped by 'key'.
*/
bool qdict_get_bool(const QDict *qdict, const char *key)
{
return qbool_get_bool(qobject_to_qbool(qdict_get(qdict, key)));
}
/**
* qdict_get_qlist(): Get the QList mapped by 'key'
*
* This function assumes that 'key' exists and it stores a
* QList object.
*
* Return QList mapped by 'key'.
*/
QList *qdict_get_qlist(const QDict *qdict, const char *key)
{
return qobject_to_qlist(qdict_get_obj(qdict, key, QTYPE_QLIST));
}
/**
* qdict_get_qdict(): Get the QDict mapped by 'key'
*
* This function assumes that 'key' exists and it stores a
* QDict object.
*
* Return QDict mapped by 'key'.
*/
QDict *qdict_get_qdict(const QDict *qdict, const char *key)
{
return qobject_to_qdict(qdict_get(qdict, key));
}
/**
* qdict_get_str(): Get a pointer to the stored string mapped
* by 'key'
*
* This function assumes that 'key' exists and it stores a
* QString object.
*
* Return pointer to the string mapped by 'key'.
*/
const char *qdict_get_str(const QDict *qdict, const char *key)
{
return qstring_get_str(qobject_to_qstring(qdict_get(qdict, key)));
}
/**
* qdict_get_try_int(): Try to get integer mapped by 'key'
*
* Return integer mapped by 'key', if it is not present in
* the dictionary or if the stored object is not of QInt type
* 'def_value' will be returned.
*/
int64_t qdict_get_try_int(const QDict *qdict, const char *key,
int64_t def_value)
{
QInt *qint = qobject_to_qint(qdict_get(qdict, key));
return qint ? qint_get_int(qint) : def_value;
}
/**
* qdict_get_try_bool(): Try to get a bool mapped by 'key'
*
* Return bool mapped by 'key', if it is not present in the
* dictionary or if the stored object is not of QBool type
* 'def_value' will be returned.
*/
bool qdict_get_try_bool(const QDict *qdict, const char *key, bool def_value)
{
QBool *qbool = qobject_to_qbool(qdict_get(qdict, key));
return qbool ? qbool_get_bool(qbool) : def_value;
}
/**
* qdict_get_try_str(): Try to get a pointer to the stored string
* mapped by 'key'
*
* Return a pointer to the string mapped by 'key', if it is not present
* in the dictionary or if the stored object is not of QString type
* NULL will be returned.
*/
const char *qdict_get_try_str(const QDict *qdict, const char *key)
{
QString *qstr = qobject_to_qstring(qdict_get(qdict, key));
return qstr ? qstring_get_str(qstr) : NULL;
}
/**
* qdict_iter(): Iterate over all the dictionary's stored values.
*
* This function allows the user to provide an iterator, which will be
* called for each stored value in the dictionary.
*/
void qdict_iter(const QDict *qdict,
void (*iter)(const char *key, QObject *obj, void *opaque),
void *opaque)
{
int i;
QDictEntry *entry;
for (i = 0; i < QDICT_BUCKET_MAX; i++) {
QLIST_FOREACH(entry, &qdict->table[i], next)
iter(entry->key, entry->value, opaque);
}
}
static QDictEntry *qdict_next_entry(const QDict *qdict, int first_bucket)
{
int i;
for (i = first_bucket; i < QDICT_BUCKET_MAX; i++) {
if (!QLIST_EMPTY(&qdict->table[i])) {
return QLIST_FIRST(&qdict->table[i]);
}
}
return NULL;
}
/**
* qdict_first(): Return first qdict entry for iteration.
*/
const QDictEntry *qdict_first(const QDict *qdict)
{
return qdict_next_entry(qdict, 0);
}
/**
* qdict_next(): Return next qdict entry in an iteration.
*/
const QDictEntry *qdict_next(const QDict *qdict, const QDictEntry *entry)
{
QDictEntry *ret;
ret = QLIST_NEXT(entry, next);
if (!ret) {
unsigned int bucket = tdb_hash(entry->key) % QDICT_BUCKET_MAX;
ret = qdict_next_entry(qdict, bucket + 1);
}
return ret;
}
/**
* qdict_clone_shallow(): Clones a given QDict. Its entries are not copied, but
* another reference is added.
*/
QDict *qdict_clone_shallow(const QDict *src)
{
QDict *dest;
QDictEntry *entry;
int i;
dest = qdict_new();
for (i = 0; i < QDICT_BUCKET_MAX; i++) {
QLIST_FOREACH(entry, &src->table[i], next) {
qobject_incref(entry->value);
qdict_put_obj(dest, entry->key, entry->value);
}
}
return dest;
}
/**
* qentry_destroy(): Free all the memory allocated by a QDictEntry
*/
static void qentry_destroy(QDictEntry *e)
{
assert(e != NULL);
assert(e->key != NULL);
assert(e->value != NULL);
qobject_decref(e->value);
g_free(e->key);
g_free(e);
}
/**
* qdict_del(): Delete a 'key:value' pair from the dictionary
*
* This will destroy all data allocated by this entry.
*/
void qdict_del(QDict *qdict, const char *key)
{
QDictEntry *entry;
entry = qdict_find(qdict, key, tdb_hash(key) % QDICT_BUCKET_MAX);
if (entry) {
QLIST_REMOVE(entry, next);
qentry_destroy(entry);
qdict->size--;
}
}
/**
* qdict_destroy_obj(): Free all the memory allocated by a QDict
*/
void qdict_destroy_obj(QObject *obj)
{
int i;
QDict *qdict;
assert(obj != NULL);
qdict = qobject_to_qdict(obj);
for (i = 0; i < QDICT_BUCKET_MAX; i++) {
QDictEntry *entry = QLIST_FIRST(&qdict->table[i]);
while (entry) {
QDictEntry *tmp = QLIST_NEXT(entry, next);
QLIST_REMOVE(entry, next);
qentry_destroy(entry);
entry = tmp;
}
}
g_free(qdict);
}
/**
* 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) {
qobject_incref(val);
qdict_put_obj(dst, key, 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(dst, key, qstring_from_str(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;
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);
new_key = g_strdup_printf("%s.%i", prefix, i);
if (qobject_type(value) == QTYPE_QDICT) {
qdict_flatten_qdict(qobject_to_qdict(value), target, new_key);
} else if (qobject_type(value) == QTYPE_QLIST) {
qdict_flatten_qlist(qobject_to_qlist(value), target, new_key);
} else {
/* All other types are moved to the target unchanged. */
qobject_incref(value);
qdict_put_obj(target, new_key, value);
}
g_free(new_key);
}
}
static void qdict_flatten_qdict(QDict *qdict, QDict *target, const char *prefix)
{
QObject *value;
const QDictEntry *entry, *next;
char *new_key;
bool delete;
entry = qdict_first(qdict);
while (entry != NULL) {
next = qdict_next(qdict, entry);
value = qdict_entry_value(entry);
new_key = NULL;
delete = false;
if (prefix) {
new_key = g_strdup_printf("%s.%s", prefix, entry->key);
}
if (qobject_type(value) == QTYPE_QDICT) {
/* Entries of QDicts are processed recursively, the QDict object
* itself disappears. */
qdict_flatten_qdict(qobject_to_qdict(value), target,
new_key ? new_key : entry->key);
delete = true;
} else if (qobject_type(value) == QTYPE_QLIST) {
qdict_flatten_qlist(qobject_to_qlist(value), target,
new_key ? new_key : entry->key);
delete = true;
} else if (prefix) {
/* All other objects are moved to the target unchanged. */
qobject_incref(value);
qdict_put_obj(target, new_key, value);
delete = true;
}
g_free(new_key);
if (delete) {
qdict_del(qdict, entry->key);
/* Restart loop after modifying the iterated QDict */
entry = qdict_first(qdict);
continue;
}
entry = next;
}
}
/**
* qdict_flatten(): For each nested 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
* 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 */
void qdict_extract_subqdict(QDict *src, QDict **dst, const char *start)
{
const QDictEntry *entry, *next;
const char *p;
*dst = qdict_new();
entry = qdict_first(src);
while (entry != NULL) {
next = qdict_next(src, entry);
if (strstart(entry->key, start, &p)) {
qobject_incref(entry->value);
qdict_put_obj(*dst, p, 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);
} else {
qobject_incref(subqobj);
qdict_del(src, indexstr);
}
qlist_append_obj(*dst, subqobj ?: QOBJECT(subqdict));
}
}
/**
* 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)) {
qobject_incref(entry->value);
qdict_put_obj(dest, entry->key, entry->value);
qdict_del(src, entry->key);
}
entry = next;
}
}