Markus Armbruster | d454dbe | 2017-02-28 22:26:49 +0100 | [diff] [blame] | 1 | /* |
| 2 | * Parsing KEY=VALUE,... strings |
| 3 | * |
| 4 | * Copyright (C) 2017 Red Hat Inc. |
| 5 | * |
| 6 | * Authors: |
| 7 | * Markus Armbruster <armbru@redhat.com>, |
| 8 | * |
| 9 | * This work is licensed under the terms of the GNU GPL, version 2 or later. |
| 10 | * See the COPYING file in the top-level directory. |
| 11 | */ |
| 12 | |
| 13 | /* |
| 14 | * KEY=VALUE,... syntax: |
| 15 | * |
| 16 | * key-vals = [ key-val { ',' key-val } [ ',' ] ] |
| 17 | * key-val = key '=' val |
| 18 | * key = key-fragment { '.' key-fragment } |
| 19 | * key-fragment = / [^=,.]* / |
| 20 | * val = { / [^,]* / | ',,' } |
| 21 | * |
| 22 | * Semantics defined by reduction to JSON: |
| 23 | * |
Markus Armbruster | fae425d | 2017-03-20 13:55:45 +0100 | [diff] [blame] | 24 | * key-vals specifies a JSON object, i.e. a tree whose root is an |
| 25 | * object, inner nodes other than the root are objects or arrays, |
| 26 | * and leaves are strings. |
Markus Armbruster | d454dbe | 2017-02-28 22:26:49 +0100 | [diff] [blame] | 27 | * |
Markus Armbruster | fae425d | 2017-03-20 13:55:45 +0100 | [diff] [blame] | 28 | * Each key-val = key-fragment '.' ... '=' val specifies a path from |
| 29 | * root to a leaf (left of '='), and the leaf's value (right of |
| 30 | * '='). |
Markus Armbruster | d454dbe | 2017-02-28 22:26:49 +0100 | [diff] [blame] | 31 | * |
Markus Armbruster | fae425d | 2017-03-20 13:55:45 +0100 | [diff] [blame] | 32 | * A path from the root is defined recursively: |
| 33 | * L '.' key-fragment is a child of the node denoted by path L |
| 34 | * key-fragment is a child of the tree root |
| 35 | * If key-fragment is numeric, the parent is an array and the child |
| 36 | * is its key-fragment-th member, counting from zero. |
| 37 | * Else, the parent is an object, and the child is its member named |
| 38 | * key-fragment. |
Markus Armbruster | d454dbe | 2017-02-28 22:26:49 +0100 | [diff] [blame] | 39 | * |
Markus Armbruster | fae425d | 2017-03-20 13:55:45 +0100 | [diff] [blame] | 40 | * This constrains inner nodes to be either array or object. The |
| 41 | * constraints must be satisfiable. Counter-example: a.b=1,a=2 is |
| 42 | * not, because root.a must be an object to satisfy a.b=1 and a |
| 43 | * string to satisfy a=2. |
| 44 | * |
| 45 | * Array subscripts can occur in any order, but the set of |
| 46 | * subscripts must not have gaps. For instance, a.1=v is not okay, |
| 47 | * because root.a[0] is missing. |
| 48 | * |
| 49 | * If multiple key-val denote the same leaf, the last one determines |
| 50 | * the value. |
| 51 | * |
| 52 | * Key-fragments must be valid QAPI names or consist only of decimal |
| 53 | * digits. |
Markus Armbruster | f740048 | 2017-02-28 22:27:05 +0100 | [diff] [blame] | 54 | * |
Markus Armbruster | d454dbe | 2017-02-28 22:26:49 +0100 | [diff] [blame] | 55 | * The length of any key-fragment must be between 1 and 127. |
| 56 | * |
Markus Armbruster | 0b2c1be | 2017-02-28 22:27:10 +0100 | [diff] [blame] | 57 | * Design flaw: there is no way to denote an empty array or non-root |
| 58 | * object. While interpreting "key absent" as empty seems natural |
Markus Armbruster | d454dbe | 2017-02-28 22:26:49 +0100 | [diff] [blame] | 59 | * (removing a key-val from the input string removes the member when |
| 60 | * there are more, so why not when it's the last), it doesn't work: |
Markus Armbruster | 0b2c1be | 2017-02-28 22:27:10 +0100 | [diff] [blame] | 61 | * "key absent" already means "optional object/array absent", which |
| 62 | * isn't the same as "empty object/array present". |
Markus Armbruster | d454dbe | 2017-02-28 22:26:49 +0100 | [diff] [blame] | 63 | * |
Markus Armbruster | 0ee9ae7 | 2017-03-20 13:55:47 +0100 | [diff] [blame] | 64 | * Design flaw: scalar values can only be strings; there is no way to |
| 65 | * denote numbers, true, false or null. The special QObject input |
| 66 | * visitor returned by qobject_input_visitor_new_keyval() mostly hides |
| 67 | * this by automatically converting strings to the type the visitor |
Markus Armbruster | c064477 | 2017-05-22 18:42:15 +0200 | [diff] [blame] | 68 | * expects. Breaks down for type 'any', where the visitor's |
| 69 | * expectation isn't clear. Code visiting 'any' needs to do the |
| 70 | * conversion itself, but only when using this keyval visitor. |
| 71 | * Awkward. Note that we carefully restrict alternate types to avoid |
| 72 | * similar ambiguity. |
Markus Armbruster | 0ee9ae7 | 2017-03-20 13:55:47 +0100 | [diff] [blame] | 73 | * |
Markus Armbruster | d454dbe | 2017-02-28 22:26:49 +0100 | [diff] [blame] | 74 | * Additional syntax for use with an implied key: |
| 75 | * |
| 76 | * key-vals-ik = val-no-key [ ',' key-vals ] |
| 77 | * val-no-key = / [^=,]* / |
| 78 | * |
| 79 | * where no-key is syntactic sugar for implied-key=val-no-key. |
Markus Armbruster | d454dbe | 2017-02-28 22:26:49 +0100 | [diff] [blame] | 80 | */ |
| 81 | |
| 82 | #include "qemu/osdep.h" |
| 83 | #include "qapi/error.h" |
Markus Armbruster | 452fcdb | 2018-02-01 12:18:39 +0100 | [diff] [blame] | 84 | #include "qapi/qmp/qdict.h" |
Markus Armbruster | 47e6b29 | 2018-02-01 12:18:38 +0100 | [diff] [blame] | 85 | #include "qapi/qmp/qlist.h" |
Markus Armbruster | d454dbe | 2017-02-28 22:26:49 +0100 | [diff] [blame] | 86 | #include "qapi/qmp/qstring.h" |
Markus Armbruster | 0b2c1be | 2017-02-28 22:27:10 +0100 | [diff] [blame] | 87 | #include "qemu/cutils.h" |
Markus Armbruster | d454dbe | 2017-02-28 22:26:49 +0100 | [diff] [blame] | 88 | #include "qemu/option.h" |
| 89 | |
| 90 | /* |
Markus Armbruster | 0b2c1be | 2017-02-28 22:27:10 +0100 | [diff] [blame] | 91 | * Convert @key to a list index. |
Markus Armbruster | fae425d | 2017-03-20 13:55:45 +0100 | [diff] [blame] | 92 | * Convert all leading decimal digits to a (non-negative) number, |
| 93 | * capped at INT_MAX. |
Markus Armbruster | 0b2c1be | 2017-02-28 22:27:10 +0100 | [diff] [blame] | 94 | * If @end is non-null, assign a pointer to the first character after |
| 95 | * the number to *@end. |
| 96 | * Else, fail if any characters follow. |
| 97 | * On success, return the converted number. |
| 98 | * On failure, return a negative value. |
| 99 | * Note: since only digits are converted, no two keys can map to the |
| 100 | * same number, except by overflow to INT_MAX. |
| 101 | */ |
| 102 | static int key_to_index(const char *key, const char **end) |
| 103 | { |
| 104 | int ret; |
| 105 | unsigned long index; |
| 106 | |
| 107 | if (*key < '0' || *key > '9') { |
| 108 | return -EINVAL; |
| 109 | } |
| 110 | ret = qemu_strtoul(key, end, 10, &index); |
| 111 | if (ret) { |
| 112 | return ret == -ERANGE ? INT_MAX : ret; |
| 113 | } |
| 114 | return index <= INT_MAX ? index : INT_MAX; |
| 115 | } |
| 116 | |
| 117 | /* |
Markus Armbruster | d454dbe | 2017-02-28 22:26:49 +0100 | [diff] [blame] | 118 | * Ensure @cur maps @key_in_cur the right way. |
| 119 | * If @value is null, it needs to map to a QDict, else to this |
| 120 | * QString. |
| 121 | * If @cur doesn't have @key_in_cur, put an empty QDict or @value, |
| 122 | * respectively. |
| 123 | * Else, if it needs to map to a QDict, and already does, do nothing. |
| 124 | * Else, if it needs to map to this QString, and already maps to a |
| 125 | * QString, replace it by @value. |
| 126 | * Else, fail because we have conflicting needs on how to map |
| 127 | * @key_in_cur. |
| 128 | * In any case, take over the reference to @value, i.e. if the caller |
Marc-André Lureau | cb3e7f0 | 2018-04-19 17:01:43 +0200 | [diff] [blame] | 129 | * wants to hold on to a reference, it needs to qobject_ref(). |
Markus Armbruster | d454dbe | 2017-02-28 22:26:49 +0100 | [diff] [blame] | 130 | * Use @key up to @key_cursor to identify the key in error messages. |
| 131 | * On success, return the mapped value. |
| 132 | * On failure, store an error through @errp and return NULL. |
| 133 | */ |
| 134 | static QObject *keyval_parse_put(QDict *cur, |
| 135 | const char *key_in_cur, QString *value, |
| 136 | const char *key, const char *key_cursor, |
| 137 | Error **errp) |
| 138 | { |
| 139 | QObject *old, *new; |
| 140 | |
| 141 | old = qdict_get(cur, key_in_cur); |
| 142 | if (old) { |
| 143 | if (qobject_type(old) != (value ? QTYPE_QSTRING : QTYPE_QDICT)) { |
| 144 | error_setg(errp, "Parameters '%.*s.*' used inconsistently", |
| 145 | (int)(key_cursor - key), key); |
Marc-André Lureau | cb3e7f0 | 2018-04-19 17:01:43 +0200 | [diff] [blame] | 146 | qobject_unref(value); |
Markus Armbruster | d454dbe | 2017-02-28 22:26:49 +0100 | [diff] [blame] | 147 | return NULL; |
| 148 | } |
| 149 | if (!value) { |
| 150 | return old; /* already QDict, do nothing */ |
| 151 | } |
| 152 | new = QOBJECT(value); /* replacement */ |
| 153 | } else { |
| 154 | new = value ? QOBJECT(value) : QOBJECT(qdict_new()); |
| 155 | } |
| 156 | qdict_put_obj(cur, key_in_cur, new); |
| 157 | return new; |
| 158 | } |
| 159 | |
| 160 | /* |
| 161 | * Parse one KEY=VALUE from @params, store result in @qdict. |
| 162 | * The first fragment of KEY applies to @qdict. Subsequent fragments |
| 163 | * apply to nested QDicts, which are created on demand. @implied_key |
| 164 | * is as in keyval_parse(). |
| 165 | * On success, return a pointer to the next KEY=VALUE, or else to '\0'. |
| 166 | * On failure, return NULL. |
| 167 | */ |
| 168 | static const char *keyval_parse_one(QDict *qdict, const char *params, |
| 169 | const char *implied_key, |
| 170 | Error **errp) |
| 171 | { |
Markus Armbruster | 0b2c1be | 2017-02-28 22:27:10 +0100 | [diff] [blame] | 172 | const char *key, *key_end, *s, *end; |
Markus Armbruster | d454dbe | 2017-02-28 22:26:49 +0100 | [diff] [blame] | 173 | size_t len; |
| 174 | char key_in_cur[128]; |
| 175 | QDict *cur; |
Markus Armbruster | f740048 | 2017-02-28 22:27:05 +0100 | [diff] [blame] | 176 | int ret; |
Markus Armbruster | d454dbe | 2017-02-28 22:26:49 +0100 | [diff] [blame] | 177 | QObject *next; |
| 178 | QString *val; |
| 179 | |
| 180 | key = params; |
| 181 | len = strcspn(params, "=,"); |
| 182 | if (implied_key && len && key[len] != '=') { |
| 183 | /* Desugar implied key */ |
| 184 | key = implied_key; |
| 185 | len = strlen(implied_key); |
| 186 | } |
| 187 | key_end = key + len; |
| 188 | |
| 189 | /* |
| 190 | * Loop over key fragments: @s points to current fragment, it |
| 191 | * applies to @cur. @key_in_cur[] holds the previous fragment. |
| 192 | */ |
| 193 | cur = qdict; |
| 194 | s = key; |
| 195 | for (;;) { |
Markus Armbruster | 0b2c1be | 2017-02-28 22:27:10 +0100 | [diff] [blame] | 196 | /* Want a key index (unless it's first) or a QAPI name */ |
| 197 | if (s != key && key_to_index(s, &end) >= 0) { |
| 198 | len = end - s; |
| 199 | } else { |
| 200 | ret = parse_qapi_name(s, false); |
| 201 | len = ret < 0 ? 0 : ret; |
| 202 | } |
Markus Armbruster | f740048 | 2017-02-28 22:27:05 +0100 | [diff] [blame] | 203 | assert(s + len <= key_end); |
| 204 | if (!len || (s + len < key_end && s[len] != '.')) { |
Markus Armbruster | d454dbe | 2017-02-28 22:26:49 +0100 | [diff] [blame] | 205 | assert(key != implied_key); |
| 206 | error_setg(errp, "Invalid parameter '%.*s'", |
| 207 | (int)(key_end - key), key); |
| 208 | return NULL; |
| 209 | } |
| 210 | if (len >= sizeof(key_in_cur)) { |
| 211 | assert(key != implied_key); |
| 212 | error_setg(errp, "Parameter%s '%.*s' is too long", |
| 213 | s != key || s + len != key_end ? " fragment" : "", |
| 214 | (int)len, s); |
| 215 | return NULL; |
| 216 | } |
| 217 | |
| 218 | if (s != key) { |
| 219 | next = keyval_parse_put(cur, key_in_cur, NULL, |
| 220 | key, s - 1, errp); |
| 221 | if (!next) { |
| 222 | return NULL; |
| 223 | } |
Max Reitz | 7dc847e | 2018-02-24 16:40:29 +0100 | [diff] [blame] | 224 | cur = qobject_to(QDict, next); |
Markus Armbruster | d454dbe | 2017-02-28 22:26:49 +0100 | [diff] [blame] | 225 | assert(cur); |
| 226 | } |
| 227 | |
| 228 | memcpy(key_in_cur, s, len); |
| 229 | key_in_cur[len] = 0; |
| 230 | s += len; |
| 231 | |
| 232 | if (*s != '.') { |
| 233 | break; |
| 234 | } |
| 235 | s++; |
| 236 | } |
| 237 | |
| 238 | if (key == implied_key) { |
| 239 | assert(!*s); |
| 240 | s = params; |
| 241 | } else { |
| 242 | if (*s != '=') { |
| 243 | error_setg(errp, "Expected '=' after parameter '%.*s'", |
| 244 | (int)(s - key), key); |
| 245 | return NULL; |
| 246 | } |
| 247 | s++; |
| 248 | } |
| 249 | |
| 250 | val = qstring_new(); |
| 251 | for (;;) { |
| 252 | if (!*s) { |
| 253 | break; |
| 254 | } else if (*s == ',') { |
| 255 | s++; |
| 256 | if (*s != ',') { |
| 257 | break; |
| 258 | } |
| 259 | } |
| 260 | qstring_append_chr(val, *s++); |
| 261 | } |
| 262 | |
| 263 | if (!keyval_parse_put(cur, key_in_cur, val, key, key_end, errp)) { |
| 264 | return NULL; |
| 265 | } |
| 266 | return s; |
| 267 | } |
| 268 | |
Markus Armbruster | 0b2c1be | 2017-02-28 22:27:10 +0100 | [diff] [blame] | 269 | static char *reassemble_key(GSList *key) |
| 270 | { |
| 271 | GString *s = g_string_new(""); |
| 272 | GSList *p; |
| 273 | |
| 274 | for (p = key; p; p = p->next) { |
| 275 | g_string_prepend_c(s, '.'); |
| 276 | g_string_prepend(s, (char *)p->data); |
| 277 | } |
| 278 | |
| 279 | return g_string_free(s, FALSE); |
| 280 | } |
| 281 | |
| 282 | /* |
| 283 | * Listify @cur recursively. |
| 284 | * Replace QDicts whose keys are all valid list indexes by QLists. |
| 285 | * @key_of_cur is the list of key fragments leading up to @cur. |
| 286 | * On success, return either @cur or its replacement. |
| 287 | * On failure, store an error through @errp and return NULL. |
| 288 | */ |
| 289 | static QObject *keyval_listify(QDict *cur, GSList *key_of_cur, Error **errp) |
| 290 | { |
| 291 | GSList key_node; |
| 292 | bool has_index, has_member; |
| 293 | const QDictEntry *ent; |
| 294 | QDict *qdict; |
| 295 | QObject *val; |
| 296 | char *key; |
| 297 | size_t nelt; |
| 298 | QObject **elt; |
| 299 | int index, max_index, i; |
| 300 | QList *list; |
| 301 | |
| 302 | key_node.next = key_of_cur; |
| 303 | |
| 304 | /* |
| 305 | * Recursively listify @cur's members, and figure out whether @cur |
| 306 | * itself is to be listified. |
| 307 | */ |
| 308 | has_index = false; |
| 309 | has_member = false; |
| 310 | for (ent = qdict_first(cur); ent; ent = qdict_next(cur, ent)) { |
| 311 | if (key_to_index(ent->key, NULL) >= 0) { |
| 312 | has_index = true; |
| 313 | } else { |
| 314 | has_member = true; |
| 315 | } |
| 316 | |
Max Reitz | 7dc847e | 2018-02-24 16:40:29 +0100 | [diff] [blame] | 317 | qdict = qobject_to(QDict, ent->value); |
Markus Armbruster | 0b2c1be | 2017-02-28 22:27:10 +0100 | [diff] [blame] | 318 | if (!qdict) { |
| 319 | continue; |
| 320 | } |
| 321 | |
| 322 | key_node.data = ent->key; |
| 323 | val = keyval_listify(qdict, &key_node, errp); |
| 324 | if (!val) { |
| 325 | return NULL; |
| 326 | } |
| 327 | if (val != ent->value) { |
| 328 | qdict_put_obj(cur, ent->key, val); |
| 329 | } |
| 330 | } |
| 331 | |
| 332 | if (has_index && has_member) { |
| 333 | key = reassemble_key(key_of_cur); |
| 334 | error_setg(errp, "Parameters '%s*' used inconsistently", key); |
| 335 | g_free(key); |
| 336 | return NULL; |
| 337 | } |
| 338 | if (!has_index) { |
| 339 | return QOBJECT(cur); |
| 340 | } |
| 341 | |
| 342 | /* Copy @cur's values to @elt[] */ |
| 343 | nelt = qdict_size(cur) + 1; /* one extra, for use as sentinel */ |
| 344 | elt = g_new0(QObject *, nelt); |
| 345 | max_index = -1; |
| 346 | for (ent = qdict_first(cur); ent; ent = qdict_next(cur, ent)) { |
| 347 | index = key_to_index(ent->key, NULL); |
| 348 | assert(index >= 0); |
| 349 | if (index > max_index) { |
| 350 | max_index = index; |
| 351 | } |
| 352 | /* |
| 353 | * We iterate @nelt times. If we get one exceeding @nelt |
| 354 | * here, we will put less than @nelt values into @elt[], |
| 355 | * triggering the error in the next loop. |
| 356 | */ |
| 357 | if ((size_t)index >= nelt - 1) { |
| 358 | continue; |
| 359 | } |
| 360 | /* Even though dict keys are distinct, indexes need not be */ |
| 361 | elt[index] = ent->value; |
| 362 | } |
| 363 | |
| 364 | /* |
Markus Armbruster | fae425d | 2017-03-20 13:55:45 +0100 | [diff] [blame] | 365 | * Make a list from @elt[], reporting the first missing element, |
| 366 | * if any. |
Markus Armbruster | 0b2c1be | 2017-02-28 22:27:10 +0100 | [diff] [blame] | 367 | * If we dropped an index >= nelt in the previous loop, this loop |
| 368 | * will run into the sentinel and report index @nelt missing. |
| 369 | */ |
| 370 | list = qlist_new(); |
| 371 | assert(!elt[nelt-1]); /* need the sentinel to be null */ |
| 372 | for (i = 0; i < MIN(nelt, max_index + 1); i++) { |
| 373 | if (!elt[i]) { |
| 374 | key = reassemble_key(key_of_cur); |
| 375 | error_setg(errp, "Parameter '%s%d' missing", key, i); |
| 376 | g_free(key); |
| 377 | g_free(elt); |
Marc-André Lureau | cb3e7f0 | 2018-04-19 17:01:43 +0200 | [diff] [blame] | 378 | qobject_unref(list); |
Markus Armbruster | 0b2c1be | 2017-02-28 22:27:10 +0100 | [diff] [blame] | 379 | return NULL; |
| 380 | } |
Marc-André Lureau | cb3e7f0 | 2018-04-19 17:01:43 +0200 | [diff] [blame] | 381 | qobject_ref(elt[i]); |
Markus Armbruster | 0b2c1be | 2017-02-28 22:27:10 +0100 | [diff] [blame] | 382 | qlist_append_obj(list, elt[i]); |
| 383 | } |
| 384 | |
| 385 | g_free(elt); |
| 386 | return QOBJECT(list); |
| 387 | } |
| 388 | |
Markus Armbruster | d454dbe | 2017-02-28 22:26:49 +0100 | [diff] [blame] | 389 | /* |
| 390 | * Parse @params in QEMU's traditional KEY=VALUE,... syntax. |
| 391 | * If @implied_key, the first KEY= can be omitted. @implied_key is |
| 392 | * implied then, and VALUE can't be empty or contain ',' or '='. |
| 393 | * On success, return a dictionary of the parsed keys and values. |
| 394 | * On failure, store an error through @errp and return NULL. |
| 395 | */ |
| 396 | QDict *keyval_parse(const char *params, const char *implied_key, |
| 397 | Error **errp) |
| 398 | { |
| 399 | QDict *qdict = qdict_new(); |
Markus Armbruster | 0b2c1be | 2017-02-28 22:27:10 +0100 | [diff] [blame] | 400 | QObject *listified; |
Markus Armbruster | d454dbe | 2017-02-28 22:26:49 +0100 | [diff] [blame] | 401 | const char *s; |
| 402 | |
| 403 | s = params; |
| 404 | while (*s) { |
| 405 | s = keyval_parse_one(qdict, s, implied_key, errp); |
| 406 | if (!s) { |
Marc-André Lureau | cb3e7f0 | 2018-04-19 17:01:43 +0200 | [diff] [blame] | 407 | qobject_unref(qdict); |
Markus Armbruster | d454dbe | 2017-02-28 22:26:49 +0100 | [diff] [blame] | 408 | return NULL; |
| 409 | } |
| 410 | implied_key = NULL; |
| 411 | } |
| 412 | |
Markus Armbruster | 0b2c1be | 2017-02-28 22:27:10 +0100 | [diff] [blame] | 413 | listified = keyval_listify(qdict, NULL, errp); |
| 414 | if (!listified) { |
Marc-André Lureau | cb3e7f0 | 2018-04-19 17:01:43 +0200 | [diff] [blame] | 415 | qobject_unref(qdict); |
Markus Armbruster | 0b2c1be | 2017-02-28 22:27:10 +0100 | [diff] [blame] | 416 | return NULL; |
| 417 | } |
| 418 | assert(listified == QOBJECT(qdict)); |
Markus Armbruster | d454dbe | 2017-02-28 22:26:49 +0100 | [diff] [blame] | 419 | return qdict; |
| 420 | } |