| /* |
| * 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 |
| * key = key-fragment { '.' key-fragment } |
| * key-fragment = / [^=,.]* / |
| * val = { / [^,]* / | ',,' } |
| * |
| * 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. |
| * |
| * 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. |
| * |
| * Additional syntax for use with an implied key: |
| * |
| * key-vals-ik = val-no-key [ ',' key-vals ] |
| * val-no-key = / [^=,]* / |
| * |
| * where no-key is syntactic sugar for implied-key=val-no-key. |
| */ |
| |
| #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/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 KEY=VALUE from @params, 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(). |
| * On success, return a pointer to the next KEY=VALUE, or else to '\0'. |
| * On failure, return NULL. |
| */ |
| static const char *keyval_parse_one(QDict *qdict, const char *params, |
| const char *implied_key, |
| Error **errp) |
| { |
| const char *key, *key_end, *s, *end; |
| size_t len; |
| char key_in_cur[128]; |
| QDict *cur; |
| int ret; |
| QObject *next; |
| QString *val; |
| |
| key = params; |
| len = strcspn(params, "=,"); |
| if (implied_key && len && key[len] != '=') { |
| /* Desugar implied key */ |
| key = implied_key; |
| 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); |
| s = params; |
| } else { |
| if (*s != '=') { |
| error_setg(errp, "Expected '=' after parameter '%.*s'", |
| (int)(s - key), key); |
| return NULL; |
| } |
| s++; |
| } |
| |
| val = qstring_new(); |
| for (;;) { |
| if (!*s) { |
| break; |
| } else if (*s == ',') { |
| s++; |
| if (*s != ',') { |
| break; |
| } |
| } |
| qstring_append_chr(val, *s++); |
| } |
| |
| if (!keyval_parse_put(cur, key_in_cur, 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); |
| } |
| |
| /* |
| * 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 '='. |
| * 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, |
| Error **errp) |
| { |
| QDict *qdict = qdict_new(); |
| QObject *listified; |
| const char *s; |
| |
| s = params; |
| while (*s) { |
| s = keyval_parse_one(qdict, s, implied_key, errp); |
| if (!s) { |
| qobject_unref(qdict); |
| return NULL; |
| } |
| implied_key = NULL; |
| } |
| |
| listified = keyval_listify(qdict, NULL, errp); |
| if (!listified) { |
| qobject_unref(qdict); |
| return NULL; |
| } |
| assert(listified == QOBJECT(qdict)); |
| return qdict; |
| } |