580 lines
18 KiB
C
580 lines
18 KiB
C
/*
|
|
* Parsing KEY=VALUE,... strings
|
|
*
|
|
* Copyright (C) 2017 Red Hat Inc.
|
|
*
|
|
* Authors:
|
|
* Markus Armbruster <armbru@redhat.com>,
|
|
*
|
|
* This work is licensed under the terms of the GNU GPL, version 2 or later.
|
|
* See the COPYING file in the top-level directory.
|
|
*/
|
|
|
|
/*
|
|
* KEY=VALUE,... syntax:
|
|
*
|
|
* key-vals = [ key-val { ',' key-val } [ ',' ] ]
|
|
* key-val = key '=' val | help
|
|
* key = key-fragment { '.' key-fragment }
|
|
* key-fragment = qapi-name | index
|
|
* qapi-name = '__' / [a-z0-9.-]+ / '_' / [A-Za-z][A-Za-z0-9_-]* /
|
|
* index = / [0-9]+ /
|
|
* val = { / [^,]+ / | ',,' }
|
|
* help = 'help' | '?'
|
|
*
|
|
* Semantics defined by reduction to JSON:
|
|
*
|
|
* key-vals specifies a JSON object, i.e. a tree whose root is an
|
|
* object, inner nodes other than the root are objects or arrays,
|
|
* and leaves are strings.
|
|
*
|
|
* Each key-val = key-fragment '.' ... '=' val specifies a path from
|
|
* root to a leaf (left of '='), and the leaf's value (right of
|
|
* '=').
|
|
*
|
|
* A path from the root is defined recursively:
|
|
* L '.' key-fragment is a child of the node denoted by path L
|
|
* key-fragment is a child of the tree root
|
|
* If key-fragment is numeric, the parent is an array and the child
|
|
* is its key-fragment-th member, counting from zero.
|
|
* Else, the parent is an object, and the child is its member named
|
|
* key-fragment.
|
|
*
|
|
* This constrains inner nodes to be either array or object. The
|
|
* constraints must be satisfiable. Counter-example: a.b=1,a=2 is
|
|
* not, because root.a must be an object to satisfy a.b=1 and a
|
|
* string to satisfy a=2.
|
|
*
|
|
* Array subscripts can occur in any order, but the set of
|
|
* subscripts must not have gaps. For instance, a.1=v is not okay,
|
|
* because root.a[0] is missing.
|
|
*
|
|
* If multiple key-val denote the same leaf, the last one determines
|
|
* the value.
|
|
*
|
|
* Key-fragments must be valid QAPI names or consist only of decimal
|
|
* digits.
|
|
*
|
|
* The length of any key-fragment must be between 1 and 127.
|
|
*
|
|
* If any key-val is help, the object is to be treated as a help
|
|
* request.
|
|
*
|
|
* Design flaw: there is no way to denote an empty array or non-root
|
|
* object. While interpreting "key absent" as empty seems natural
|
|
* (removing a key-val from the input string removes the member when
|
|
* there are more, so why not when it's the last), it doesn't work:
|
|
* "key absent" already means "optional object/array absent", which
|
|
* isn't the same as "empty object/array present".
|
|
*
|
|
* Design flaw: scalar values can only be strings; there is no way to
|
|
* denote numbers, true, false or null. The special QObject input
|
|
* visitor returned by qobject_input_visitor_new_keyval() mostly hides
|
|
* this by automatically converting strings to the type the visitor
|
|
* expects. Breaks down for type 'any', where the visitor's
|
|
* expectation isn't clear. Code visiting 'any' needs to do the
|
|
* conversion itself, but only when using this keyval visitor.
|
|
* Awkward. Note that we carefully restrict alternate types to avoid
|
|
* similar ambiguity.
|
|
*
|
|
* Alternative syntax for use with an implied key:
|
|
*
|
|
* key-vals = [ key-val-1st { ',' key-val } [ ',' ] ]
|
|
* key-val-1st = val-no-key | key-val
|
|
* val-no-key = / [^=,]+ / - help
|
|
*
|
|
* where val-no-key is syntactic sugar for implied-key=val-no-key.
|
|
*
|
|
* Note that you can't use the sugared form when the value contains
|
|
* '=' or ','.
|
|
*/
|
|
|
|
#include "qemu/osdep.h"
|
|
#include "qapi/error.h"
|
|
#include "qapi/qmp/qdict.h"
|
|
#include "qapi/qmp/qlist.h"
|
|
#include "qapi/qmp/qstring.h"
|
|
#include "qemu/cutils.h"
|
|
#include "qemu/keyval.h"
|
|
#include "qemu/help_option.h"
|
|
|
|
/*
|
|
* Convert @key to a list index.
|
|
* Convert all leading decimal digits to a (non-negative) number,
|
|
* capped at INT_MAX.
|
|
* If @end is non-null, assign a pointer to the first character after
|
|
* the number to *@end.
|
|
* Else, fail if any characters follow.
|
|
* On success, return the converted number.
|
|
* On failure, return a negative value.
|
|
* Note: since only digits are converted, no two keys can map to the
|
|
* same number, except by overflow to INT_MAX.
|
|
*/
|
|
static int key_to_index(const char *key, const char **end)
|
|
{
|
|
int ret;
|
|
unsigned long index;
|
|
|
|
if (*key < '0' || *key > '9') {
|
|
return -EINVAL;
|
|
}
|
|
ret = qemu_strtoul(key, end, 10, &index);
|
|
if (ret) {
|
|
return ret == -ERANGE ? INT_MAX : ret;
|
|
}
|
|
return index <= INT_MAX ? index : INT_MAX;
|
|
}
|
|
|
|
/*
|
|
* Ensure @cur maps @key_in_cur the right way.
|
|
* If @value is null, it needs to map to a QDict, else to this
|
|
* QString.
|
|
* If @cur doesn't have @key_in_cur, put an empty QDict or @value,
|
|
* respectively.
|
|
* Else, if it needs to map to a QDict, and already does, do nothing.
|
|
* Else, if it needs to map to this QString, and already maps to a
|
|
* QString, replace it by @value.
|
|
* Else, fail because we have conflicting needs on how to map
|
|
* @key_in_cur.
|
|
* In any case, take over the reference to @value, i.e. if the caller
|
|
* wants to hold on to a reference, it needs to qobject_ref().
|
|
* Use @key up to @key_cursor to identify the key in error messages.
|
|
* On success, return the mapped value.
|
|
* On failure, store an error through @errp and return NULL.
|
|
*/
|
|
static QObject *keyval_parse_put(QDict *cur,
|
|
const char *key_in_cur, QString *value,
|
|
const char *key, const char *key_cursor,
|
|
Error **errp)
|
|
{
|
|
QObject *old, *new;
|
|
|
|
old = qdict_get(cur, key_in_cur);
|
|
if (old) {
|
|
if (qobject_type(old) != (value ? QTYPE_QSTRING : QTYPE_QDICT)) {
|
|
error_setg(errp, "Parameters '%.*s.*' used inconsistently",
|
|
(int)(key_cursor - key), key);
|
|
qobject_unref(value);
|
|
return NULL;
|
|
}
|
|
if (!value) {
|
|
return old; /* already QDict, do nothing */
|
|
}
|
|
new = QOBJECT(value); /* replacement */
|
|
} else {
|
|
new = value ? QOBJECT(value) : QOBJECT(qdict_new());
|
|
}
|
|
qdict_put_obj(cur, key_in_cur, new);
|
|
return new;
|
|
}
|
|
|
|
/*
|
|
* Parse one parameter from @params.
|
|
*
|
|
* If we're looking at KEY=VALUE, store result in @qdict.
|
|
* The first fragment of KEY applies to @qdict. Subsequent fragments
|
|
* apply to nested QDicts, which are created on demand. @implied_key
|
|
* is as in keyval_parse().
|
|
*
|
|
* If we're looking at "help" or "?", set *help to true.
|
|
*
|
|
* On success, return a pointer to the next parameter, or else to '\0'.
|
|
* On failure, return NULL.
|
|
*/
|
|
static const char *keyval_parse_one(QDict *qdict, const char *params,
|
|
const char *implied_key, bool *help,
|
|
Error **errp)
|
|
{
|
|
const char *key, *key_end, *val_end, *s, *end;
|
|
size_t len;
|
|
char key_in_cur[128];
|
|
QDict *cur;
|
|
int ret;
|
|
QObject *next;
|
|
GString *val;
|
|
|
|
key = params;
|
|
val_end = NULL;
|
|
len = strcspn(params, "=,");
|
|
if (len && key[len] != '=') {
|
|
if (starts_with_help_option(key) == len) {
|
|
*help = true;
|
|
s = key + len;
|
|
if (*s == ',') {
|
|
s++;
|
|
}
|
|
return s;
|
|
}
|
|
if (implied_key) {
|
|
/* Desugar implied key */
|
|
key = implied_key;
|
|
val_end = params + len;
|
|
len = strlen(implied_key);
|
|
}
|
|
}
|
|
key_end = key + len;
|
|
|
|
/*
|
|
* Loop over key fragments: @s points to current fragment, it
|
|
* applies to @cur. @key_in_cur[] holds the previous fragment.
|
|
*/
|
|
cur = qdict;
|
|
s = key;
|
|
for (;;) {
|
|
/* Want a key index (unless it's first) or a QAPI name */
|
|
if (s != key && key_to_index(s, &end) >= 0) {
|
|
len = end - s;
|
|
} else {
|
|
ret = parse_qapi_name(s, false);
|
|
len = ret < 0 ? 0 : ret;
|
|
}
|
|
assert(s + len <= key_end);
|
|
if (!len || (s + len < key_end && s[len] != '.')) {
|
|
assert(key != implied_key);
|
|
error_setg(errp, "Invalid parameter '%.*s'",
|
|
(int)(key_end - key), key);
|
|
return NULL;
|
|
}
|
|
if (len >= sizeof(key_in_cur)) {
|
|
assert(key != implied_key);
|
|
error_setg(errp, "Parameter%s '%.*s' is too long",
|
|
s != key || s + len != key_end ? " fragment" : "",
|
|
(int)len, s);
|
|
return NULL;
|
|
}
|
|
|
|
if (s != key) {
|
|
next = keyval_parse_put(cur, key_in_cur, NULL,
|
|
key, s - 1, errp);
|
|
if (!next) {
|
|
return NULL;
|
|
}
|
|
cur = qobject_to(QDict, next);
|
|
assert(cur);
|
|
}
|
|
|
|
memcpy(key_in_cur, s, len);
|
|
key_in_cur[len] = 0;
|
|
s += len;
|
|
|
|
if (*s != '.') {
|
|
break;
|
|
}
|
|
s++;
|
|
}
|
|
|
|
if (key == implied_key) {
|
|
assert(!*s);
|
|
val = g_string_new_len(params, val_end - params);
|
|
s = val_end;
|
|
if (*s == ',') {
|
|
s++;
|
|
}
|
|
} else {
|
|
if (*s != '=') {
|
|
error_setg(errp, "Expected '=' after parameter '%.*s'",
|
|
(int)(s - key), key);
|
|
return NULL;
|
|
}
|
|
s++;
|
|
|
|
val = g_string_new(NULL);
|
|
for (;;) {
|
|
if (!*s) {
|
|
break;
|
|
} else if (*s == ',') {
|
|
s++;
|
|
if (*s != ',') {
|
|
break;
|
|
}
|
|
}
|
|
g_string_append_c(val, *s++);
|
|
}
|
|
}
|
|
|
|
if (!keyval_parse_put(cur, key_in_cur, qstring_from_gstring(val),
|
|
key, key_end, errp)) {
|
|
return NULL;
|
|
}
|
|
return s;
|
|
}
|
|
|
|
static char *reassemble_key(GSList *key)
|
|
{
|
|
GString *s = g_string_new("");
|
|
GSList *p;
|
|
|
|
for (p = key; p; p = p->next) {
|
|
g_string_prepend_c(s, '.');
|
|
g_string_prepend(s, (char *)p->data);
|
|
}
|
|
|
|
return g_string_free(s, FALSE);
|
|
}
|
|
|
|
/*
|
|
* Recursive worker for keyval_merge.
|
|
*
|
|
* @str is the path that led to the * current dictionary (to be used for
|
|
* error messages). It is modified internally but restored before the
|
|
* function returns.
|
|
*/
|
|
static void keyval_do_merge(QDict *dest, const QDict *merged, GString *str, Error **errp)
|
|
{
|
|
size_t save_len = str->len;
|
|
const QDictEntry *ent;
|
|
QObject *old_value;
|
|
|
|
for (ent = qdict_first(merged); ent; ent = qdict_next(merged, ent)) {
|
|
old_value = qdict_get(dest, ent->key);
|
|
if (old_value) {
|
|
if (qobject_type(old_value) != qobject_type(ent->value)) {
|
|
error_setg(errp, "Parameter '%s%s' used inconsistently",
|
|
str->str, ent->key);
|
|
return;
|
|
} else if (qobject_type(ent->value) == QTYPE_QDICT) {
|
|
/* Merge sub-dictionaries. */
|
|
g_string_append(str, ent->key);
|
|
g_string_append_c(str, '.');
|
|
keyval_do_merge(qobject_to(QDict, old_value),
|
|
qobject_to(QDict, ent->value),
|
|
str, errp);
|
|
g_string_truncate(str, save_len);
|
|
continue;
|
|
} else if (qobject_type(ent->value) == QTYPE_QLIST) {
|
|
/* Append to old list. */
|
|
QList *old = qobject_to(QList, old_value);
|
|
QList *new = qobject_to(QList, ent->value);
|
|
const QListEntry *item;
|
|
QLIST_FOREACH_ENTRY(new, item) {
|
|
qobject_ref(item->value);
|
|
qlist_append_obj(old, item->value);
|
|
}
|
|
continue;
|
|
} else {
|
|
assert(qobject_type(ent->value) == QTYPE_QSTRING);
|
|
}
|
|
}
|
|
|
|
qobject_ref(ent->value);
|
|
qdict_put_obj(dest, ent->key, ent->value);
|
|
}
|
|
}
|
|
|
|
/* Merge the @merged dictionary into @dest.
|
|
*
|
|
* The dictionaries are expected to be returned by the keyval parser, and
|
|
* therefore the only expected scalar type is the string. In case the same
|
|
* path is present in both @dest and @merged, the semantics are as follows:
|
|
*
|
|
* - lists are concatenated
|
|
*
|
|
* - dictionaries are merged recursively
|
|
*
|
|
* - for scalar values, @merged wins
|
|
*
|
|
* In case an error is reported, @dest may already have been modified.
|
|
*
|
|
* This function can be used to implement semantics analogous to QemuOpts's
|
|
* .merge_lists = true case, or to implement -set for options backed by QDicts.
|
|
*
|
|
* Note: while QemuOpts is commonly used so that repeated keys overwrite
|
|
* ("last one wins"), it can also be used so that repeated keys build up
|
|
* a list. keyval_merge() can only be used when the options' semantics are
|
|
* the former, not the latter.
|
|
*/
|
|
void keyval_merge(QDict *dest, const QDict *merged, Error **errp)
|
|
{
|
|
GString *str;
|
|
|
|
str = g_string_new("");
|
|
keyval_do_merge(dest, merged, str, errp);
|
|
g_string_free(str, TRUE);
|
|
}
|
|
|
|
/*
|
|
* Listify @cur recursively.
|
|
* Replace QDicts whose keys are all valid list indexes by QLists.
|
|
* @key_of_cur is the list of key fragments leading up to @cur.
|
|
* On success, return either @cur or its replacement.
|
|
* On failure, store an error through @errp and return NULL.
|
|
*/
|
|
static QObject *keyval_listify(QDict *cur, GSList *key_of_cur, Error **errp)
|
|
{
|
|
GSList key_node;
|
|
bool has_index, has_member;
|
|
const QDictEntry *ent;
|
|
QDict *qdict;
|
|
QObject *val;
|
|
char *key;
|
|
size_t nelt;
|
|
QObject **elt;
|
|
int index, max_index, i;
|
|
QList *list;
|
|
|
|
key_node.next = key_of_cur;
|
|
|
|
/*
|
|
* Recursively listify @cur's members, and figure out whether @cur
|
|
* itself is to be listified.
|
|
*/
|
|
has_index = false;
|
|
has_member = false;
|
|
for (ent = qdict_first(cur); ent; ent = qdict_next(cur, ent)) {
|
|
if (key_to_index(ent->key, NULL) >= 0) {
|
|
has_index = true;
|
|
} else {
|
|
has_member = true;
|
|
}
|
|
|
|
qdict = qobject_to(QDict, ent->value);
|
|
if (!qdict) {
|
|
continue;
|
|
}
|
|
|
|
key_node.data = ent->key;
|
|
val = keyval_listify(qdict, &key_node, errp);
|
|
if (!val) {
|
|
return NULL;
|
|
}
|
|
if (val != ent->value) {
|
|
qdict_put_obj(cur, ent->key, val);
|
|
}
|
|
}
|
|
|
|
if (has_index && has_member) {
|
|
key = reassemble_key(key_of_cur);
|
|
error_setg(errp, "Parameters '%s*' used inconsistently", key);
|
|
g_free(key);
|
|
return NULL;
|
|
}
|
|
if (!has_index) {
|
|
return QOBJECT(cur);
|
|
}
|
|
|
|
/* Copy @cur's values to @elt[] */
|
|
nelt = qdict_size(cur) + 1; /* one extra, for use as sentinel */
|
|
elt = g_new0(QObject *, nelt);
|
|
max_index = -1;
|
|
for (ent = qdict_first(cur); ent; ent = qdict_next(cur, ent)) {
|
|
index = key_to_index(ent->key, NULL);
|
|
assert(index >= 0);
|
|
if (index > max_index) {
|
|
max_index = index;
|
|
}
|
|
/*
|
|
* We iterate @nelt times. If we get one exceeding @nelt
|
|
* here, we will put less than @nelt values into @elt[],
|
|
* triggering the error in the next loop.
|
|
*/
|
|
if ((size_t)index >= nelt - 1) {
|
|
continue;
|
|
}
|
|
/* Even though dict keys are distinct, indexes need not be */
|
|
elt[index] = ent->value;
|
|
}
|
|
|
|
/*
|
|
* Make a list from @elt[], reporting the first missing element,
|
|
* if any.
|
|
* If we dropped an index >= nelt in the previous loop, this loop
|
|
* will run into the sentinel and report index @nelt missing.
|
|
*/
|
|
list = qlist_new();
|
|
assert(!elt[nelt-1]); /* need the sentinel to be null */
|
|
for (i = 0; i < MIN(nelt, max_index + 1); i++) {
|
|
if (!elt[i]) {
|
|
key = reassemble_key(key_of_cur);
|
|
error_setg(errp, "Parameter '%s%d' missing", key, i);
|
|
g_free(key);
|
|
g_free(elt);
|
|
qobject_unref(list);
|
|
return NULL;
|
|
}
|
|
qobject_ref(elt[i]);
|
|
qlist_append_obj(list, elt[i]);
|
|
}
|
|
|
|
g_free(elt);
|
|
return QOBJECT(list);
|
|
}
|
|
|
|
/*
|
|
* Parse @params in QEMU's traditional KEY=VALUE,... syntax.
|
|
*
|
|
* If @implied_key, the first KEY= can be omitted. @implied_key is
|
|
* implied then, and VALUE can't be empty or contain ',' or '='.
|
|
*
|
|
* A parameter "help" or "?" without a value isn't added to the
|
|
* resulting dictionary, but instead is interpreted as help request.
|
|
* All other options are parsed and returned normally so that context
|
|
* specific help can be printed.
|
|
*
|
|
* If @p_help is not NULL, store whether help is requested there.
|
|
* If @p_help is NULL and help is requested, fail.
|
|
*
|
|
* On success, return @dict, now filled with the parsed keys and values.
|
|
*
|
|
* On failure, store an error through @errp and return NULL. Any keys
|
|
* and values parsed so far will be in @dict nevertheless.
|
|
*/
|
|
QDict *keyval_parse_into(QDict *qdict, const char *params, const char *implied_key,
|
|
bool *p_help, Error **errp)
|
|
{
|
|
QObject *listified;
|
|
const char *s;
|
|
bool help = false;
|
|
|
|
s = params;
|
|
while (*s) {
|
|
s = keyval_parse_one(qdict, s, implied_key, &help, errp);
|
|
if (!s) {
|
|
return NULL;
|
|
}
|
|
implied_key = NULL;
|
|
}
|
|
|
|
if (p_help) {
|
|
*p_help = help;
|
|
} else if (help) {
|
|
error_setg(errp, "Help is not available for this option");
|
|
return NULL;
|
|
}
|
|
|
|
listified = keyval_listify(qdict, NULL, errp);
|
|
if (!listified) {
|
|
return NULL;
|
|
}
|
|
assert(listified == QOBJECT(qdict));
|
|
return qdict;
|
|
}
|
|
|
|
/*
|
|
* Parse @params in QEMU's traditional KEY=VALUE,... syntax.
|
|
*
|
|
* If @implied_key, the first KEY= can be omitted. @implied_key is
|
|
* implied then, and VALUE can't be empty or contain ',' or '='.
|
|
*
|
|
* A parameter "help" or "?" without a value isn't added to the
|
|
* resulting dictionary, but instead is interpreted as help request.
|
|
* All other options are parsed and returned normally so that context
|
|
* specific help can be printed.
|
|
*
|
|
* If @p_help is not NULL, store whether help is requested there.
|
|
* If @p_help is NULL and help is requested, fail.
|
|
*
|
|
* On success, return a dictionary of the parsed keys and values.
|
|
* On failure, store an error through @errp and return NULL.
|
|
*/
|
|
QDict *keyval_parse(const char *params, const char *implied_key,
|
|
bool *p_help, Error **errp)
|
|
{
|
|
QDict *qdict = qdict_new();
|
|
QDict *ret = keyval_parse_into(qdict, params, implied_key, p_help, errp);
|
|
|
|
if (!ret) {
|
|
qobject_unref(qdict);
|
|
}
|
|
return ret;
|
|
}
|