Update version for v5.1.0-rc3 release
[qemu.git] / qobject / json-parser.c
1 /*
2 * JSON Parser
3 *
4 * Copyright IBM, Corp. 2009
5 *
6 * Authors:
7 * Anthony Liguori <aliguori@us.ibm.com>
8 *
9 * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
10 * See the COPYING.LIB file in the top-level directory.
11 *
12 */
13
14 #include "qemu/osdep.h"
15 #include "qemu/ctype.h"
16 #include "qemu/cutils.h"
17 #include "qemu/unicode.h"
18 #include "qapi/error.h"
19 #include "qapi/qmp/qbool.h"
20 #include "qapi/qmp/qdict.h"
21 #include "qapi/qmp/qlist.h"
22 #include "qapi/qmp/qnull.h"
23 #include "qapi/qmp/qnum.h"
24 #include "qapi/qmp/qstring.h"
25 #include "json-parser-int.h"
26
27 struct JSONToken {
28 JSONTokenType type;
29 int x;
30 int y;
31 char str[];
32 };
33
34 typedef struct JSONParserContext
35 {
36 Error *err;
37 JSONToken *current;
38 GQueue *buf;
39 va_list *ap;
40 } JSONParserContext;
41
42 #define BUG_ON(cond) assert(!(cond))
43
44 /**
45 * TODO
46 *
47 * 0) make errors meaningful again
48 * 1) add geometry information to tokens
49 * 3) should we return a parsed size?
50 * 4) deal with premature EOI
51 */
52
53 static QObject *parse_value(JSONParserContext *ctxt);
54
55 /**
56 * Error handler
57 */
58 static void GCC_FMT_ATTR(3, 4) parse_error(JSONParserContext *ctxt,
59 JSONToken *token, const char *msg, ...)
60 {
61 va_list ap;
62 char message[1024];
63
64 if (ctxt->err) {
65 return;
66 }
67 va_start(ap, msg);
68 vsnprintf(message, sizeof(message), msg, ap);
69 va_end(ap);
70 error_setg(&ctxt->err, "JSON parse error, %s", message);
71 }
72
73 static int cvt4hex(const char *s)
74 {
75 int cp, i;
76
77 cp = 0;
78 for (i = 0; i < 4; i++) {
79 if (!qemu_isxdigit(s[i])) {
80 return -1;
81 }
82 cp <<= 4;
83 if (s[i] >= '0' && s[i] <= '9') {
84 cp |= s[i] - '0';
85 } else if (s[i] >= 'a' && s[i] <= 'f') {
86 cp |= 10 + s[i] - 'a';
87 } else if (s[i] >= 'A' && s[i] <= 'F') {
88 cp |= 10 + s[i] - 'A';
89 } else {
90 return -1;
91 }
92 }
93 return cp;
94 }
95
96 /**
97 * parse_string(): Parse a JSON string
98 *
99 * From RFC 8259 "The JavaScript Object Notation (JSON) Data
100 * Interchange Format":
101 *
102 * char = unescaped /
103 * escape (
104 * %x22 / ; " quotation mark U+0022
105 * %x5C / ; \ reverse solidus U+005C
106 * %x2F / ; / solidus U+002F
107 * %x62 / ; b backspace U+0008
108 * %x66 / ; f form feed U+000C
109 * %x6E / ; n line feed U+000A
110 * %x72 / ; r carriage return U+000D
111 * %x74 / ; t tab U+0009
112 * %x75 4HEXDIG ) ; uXXXX U+XXXX
113 * escape = %x5C ; \
114 * quotation-mark = %x22 ; "
115 * unescaped = %x20-21 / %x23-5B / %x5D-10FFFF
116 *
117 * Extensions over RFC 8259:
118 * - Extra escape sequence in strings:
119 * 0x27 (apostrophe) is recognized after escape, too
120 * - Single-quoted strings:
121 * Like double-quoted strings, except they're delimited by %x27
122 * (apostrophe) instead of %x22 (quotation mark), and can't contain
123 * unescaped apostrophe, but can contain unescaped quotation mark.
124 *
125 * Note:
126 * - Encoding is modified UTF-8.
127 * - Invalid Unicode characters are rejected.
128 * - Control characters \x00..\x1F are rejected by the lexer.
129 */
130 static QString *parse_string(JSONParserContext *ctxt, JSONToken *token)
131 {
132 const char *ptr = token->str;
133 QString *str;
134 char quote;
135 const char *beg;
136 int cp, trailing;
137 char *end;
138 ssize_t len;
139 char utf8_buf[5];
140
141 assert(*ptr == '"' || *ptr == '\'');
142 quote = *ptr++;
143 str = qstring_new();
144
145 while (*ptr != quote) {
146 assert(*ptr);
147 switch (*ptr) {
148 case '\\':
149 beg = ptr++;
150 switch (*ptr++) {
151 case '"':
152 qstring_append_chr(str, '"');
153 break;
154 case '\'':
155 qstring_append_chr(str, '\'');
156 break;
157 case '\\':
158 qstring_append_chr(str, '\\');
159 break;
160 case '/':
161 qstring_append_chr(str, '/');
162 break;
163 case 'b':
164 qstring_append_chr(str, '\b');
165 break;
166 case 'f':
167 qstring_append_chr(str, '\f');
168 break;
169 case 'n':
170 qstring_append_chr(str, '\n');
171 break;
172 case 'r':
173 qstring_append_chr(str, '\r');
174 break;
175 case 't':
176 qstring_append_chr(str, '\t');
177 break;
178 case 'u':
179 cp = cvt4hex(ptr);
180 ptr += 4;
181
182 /* handle surrogate pairs */
183 if (cp >= 0xD800 && cp <= 0xDBFF
184 && ptr[0] == '\\' && ptr[1] == 'u') {
185 /* leading surrogate followed by \u */
186 cp = 0x10000 + ((cp & 0x3FF) << 10);
187 trailing = cvt4hex(ptr + 2);
188 if (trailing >= 0xDC00 && trailing <= 0xDFFF) {
189 /* followed by trailing surrogate */
190 cp |= trailing & 0x3FF;
191 ptr += 6;
192 } else {
193 cp = -1; /* invalid */
194 }
195 }
196
197 if (mod_utf8_encode(utf8_buf, sizeof(utf8_buf), cp) < 0) {
198 parse_error(ctxt, token,
199 "%.*s is not a valid Unicode character",
200 (int)(ptr - beg), beg);
201 goto out;
202 }
203 qstring_append(str, utf8_buf);
204 break;
205 default:
206 parse_error(ctxt, token, "invalid escape sequence in string");
207 goto out;
208 }
209 break;
210 case '%':
211 if (ctxt->ap) {
212 if (ptr[1] != '%') {
213 parse_error(ctxt, token, "can't interpolate into string");
214 goto out;
215 }
216 ptr++;
217 }
218 /* fall through */
219 default:
220 cp = mod_utf8_codepoint(ptr, 6, &end);
221 if (cp < 0) {
222 parse_error(ctxt, token, "invalid UTF-8 sequence in string");
223 goto out;
224 }
225 ptr = end;
226 len = mod_utf8_encode(utf8_buf, sizeof(utf8_buf), cp);
227 assert(len >= 0);
228 qstring_append(str, utf8_buf);
229 }
230 }
231
232 return str;
233
234 out:
235 qobject_unref(str);
236 return NULL;
237 }
238
239 /* Note: the token object returned by parser_context_peek_token or
240 * parser_context_pop_token is deleted as soon as parser_context_pop_token
241 * is called again.
242 */
243 static JSONToken *parser_context_pop_token(JSONParserContext *ctxt)
244 {
245 g_free(ctxt->current);
246 ctxt->current = g_queue_pop_head(ctxt->buf);
247 return ctxt->current;
248 }
249
250 static JSONToken *parser_context_peek_token(JSONParserContext *ctxt)
251 {
252 return g_queue_peek_head(ctxt->buf);
253 }
254
255 /**
256 * Parsing rules
257 */
258 static int parse_pair(JSONParserContext *ctxt, QDict *dict)
259 {
260 QObject *value;
261 QString *key = NULL;
262 JSONToken *peek, *token;
263
264 peek = parser_context_peek_token(ctxt);
265 if (peek == NULL) {
266 parse_error(ctxt, NULL, "premature EOI");
267 goto out;
268 }
269
270 key = qobject_to(QString, parse_value(ctxt));
271 if (!key) {
272 parse_error(ctxt, peek, "key is not a string in object");
273 goto out;
274 }
275
276 token = parser_context_pop_token(ctxt);
277 if (token == NULL) {
278 parse_error(ctxt, NULL, "premature EOI");
279 goto out;
280 }
281
282 if (token->type != JSON_COLON) {
283 parse_error(ctxt, token, "missing : in object pair");
284 goto out;
285 }
286
287 value = parse_value(ctxt);
288 if (value == NULL) {
289 parse_error(ctxt, token, "Missing value in dict");
290 goto out;
291 }
292
293 if (qdict_haskey(dict, qstring_get_str(key))) {
294 parse_error(ctxt, token, "duplicate key");
295 goto out;
296 }
297
298 qdict_put_obj(dict, qstring_get_str(key), value);
299
300 qobject_unref(key);
301
302 return 0;
303
304 out:
305 qobject_unref(key);
306
307 return -1;
308 }
309
310 static QObject *parse_object(JSONParserContext *ctxt)
311 {
312 QDict *dict = NULL;
313 JSONToken *token, *peek;
314
315 token = parser_context_pop_token(ctxt);
316 assert(token && token->type == JSON_LCURLY);
317
318 dict = qdict_new();
319
320 peek = parser_context_peek_token(ctxt);
321 if (peek == NULL) {
322 parse_error(ctxt, NULL, "premature EOI");
323 goto out;
324 }
325
326 if (peek->type != JSON_RCURLY) {
327 if (parse_pair(ctxt, dict) == -1) {
328 goto out;
329 }
330
331 token = parser_context_pop_token(ctxt);
332 if (token == NULL) {
333 parse_error(ctxt, NULL, "premature EOI");
334 goto out;
335 }
336
337 while (token->type != JSON_RCURLY) {
338 if (token->type != JSON_COMMA) {
339 parse_error(ctxt, token, "expected separator in dict");
340 goto out;
341 }
342
343 if (parse_pair(ctxt, dict) == -1) {
344 goto out;
345 }
346
347 token = parser_context_pop_token(ctxt);
348 if (token == NULL) {
349 parse_error(ctxt, NULL, "premature EOI");
350 goto out;
351 }
352 }
353 } else {
354 (void)parser_context_pop_token(ctxt);
355 }
356
357 return QOBJECT(dict);
358
359 out:
360 qobject_unref(dict);
361 return NULL;
362 }
363
364 static QObject *parse_array(JSONParserContext *ctxt)
365 {
366 QList *list = NULL;
367 JSONToken *token, *peek;
368
369 token = parser_context_pop_token(ctxt);
370 assert(token && token->type == JSON_LSQUARE);
371
372 list = qlist_new();
373
374 peek = parser_context_peek_token(ctxt);
375 if (peek == NULL) {
376 parse_error(ctxt, NULL, "premature EOI");
377 goto out;
378 }
379
380 if (peek->type != JSON_RSQUARE) {
381 QObject *obj;
382
383 obj = parse_value(ctxt);
384 if (obj == NULL) {
385 parse_error(ctxt, token, "expecting value");
386 goto out;
387 }
388
389 qlist_append_obj(list, obj);
390
391 token = parser_context_pop_token(ctxt);
392 if (token == NULL) {
393 parse_error(ctxt, NULL, "premature EOI");
394 goto out;
395 }
396
397 while (token->type != JSON_RSQUARE) {
398 if (token->type != JSON_COMMA) {
399 parse_error(ctxt, token, "expected separator in list");
400 goto out;
401 }
402
403 obj = parse_value(ctxt);
404 if (obj == NULL) {
405 parse_error(ctxt, token, "expecting value");
406 goto out;
407 }
408
409 qlist_append_obj(list, obj);
410
411 token = parser_context_pop_token(ctxt);
412 if (token == NULL) {
413 parse_error(ctxt, NULL, "premature EOI");
414 goto out;
415 }
416 }
417 } else {
418 (void)parser_context_pop_token(ctxt);
419 }
420
421 return QOBJECT(list);
422
423 out:
424 qobject_unref(list);
425 return NULL;
426 }
427
428 static QObject *parse_keyword(JSONParserContext *ctxt)
429 {
430 JSONToken *token;
431
432 token = parser_context_pop_token(ctxt);
433 assert(token && token->type == JSON_KEYWORD);
434
435 if (!strcmp(token->str, "true")) {
436 return QOBJECT(qbool_from_bool(true));
437 } else if (!strcmp(token->str, "false")) {
438 return QOBJECT(qbool_from_bool(false));
439 } else if (!strcmp(token->str, "null")) {
440 return QOBJECT(qnull());
441 }
442 parse_error(ctxt, token, "invalid keyword '%s'", token->str);
443 return NULL;
444 }
445
446 static QObject *parse_interpolation(JSONParserContext *ctxt)
447 {
448 JSONToken *token;
449
450 token = parser_context_pop_token(ctxt);
451 assert(token && token->type == JSON_INTERP);
452
453 if (!strcmp(token->str, "%p")) {
454 return va_arg(*ctxt->ap, QObject *);
455 } else if (!strcmp(token->str, "%i")) {
456 return QOBJECT(qbool_from_bool(va_arg(*ctxt->ap, int)));
457 } else if (!strcmp(token->str, "%d")) {
458 return QOBJECT(qnum_from_int(va_arg(*ctxt->ap, int)));
459 } else if (!strcmp(token->str, "%ld")) {
460 return QOBJECT(qnum_from_int(va_arg(*ctxt->ap, long)));
461 } else if (!strcmp(token->str, "%lld")) {
462 return QOBJECT(qnum_from_int(va_arg(*ctxt->ap, long long)));
463 } else if (!strcmp(token->str, "%" PRId64)) {
464 return QOBJECT(qnum_from_int(va_arg(*ctxt->ap, int64_t)));
465 } else if (!strcmp(token->str, "%u")) {
466 return QOBJECT(qnum_from_uint(va_arg(*ctxt->ap, unsigned int)));
467 } else if (!strcmp(token->str, "%lu")) {
468 return QOBJECT(qnum_from_uint(va_arg(*ctxt->ap, unsigned long)));
469 } else if (!strcmp(token->str, "%llu")) {
470 return QOBJECT(qnum_from_uint(va_arg(*ctxt->ap, unsigned long long)));
471 } else if (!strcmp(token->str, "%" PRIu64)) {
472 return QOBJECT(qnum_from_uint(va_arg(*ctxt->ap, uint64_t)));
473 } else if (!strcmp(token->str, "%s")) {
474 return QOBJECT(qstring_from_str(va_arg(*ctxt->ap, const char *)));
475 } else if (!strcmp(token->str, "%f")) {
476 return QOBJECT(qnum_from_double(va_arg(*ctxt->ap, double)));
477 }
478 parse_error(ctxt, token, "invalid interpolation '%s'", token->str);
479 return NULL;
480 }
481
482 static QObject *parse_literal(JSONParserContext *ctxt)
483 {
484 JSONToken *token;
485
486 token = parser_context_pop_token(ctxt);
487 assert(token);
488
489 switch (token->type) {
490 case JSON_STRING:
491 return QOBJECT(parse_string(ctxt, token));
492 case JSON_INTEGER: {
493 /*
494 * Represent JSON_INTEGER as QNUM_I64 if possible, else as
495 * QNUM_U64, else as QNUM_DOUBLE. Note that qemu_strtoi64()
496 * and qemu_strtou64() fail with ERANGE when it's not
497 * possible.
498 *
499 * qnum_get_int() will then work for any signed 64-bit
500 * JSON_INTEGER, qnum_get_uint() for any unsigned 64-bit
501 * integer, and qnum_get_double() both for any JSON_INTEGER
502 * and any JSON_FLOAT (with precision loss for integers beyond
503 * 53 bits)
504 */
505 int ret;
506 int64_t value;
507 uint64_t uvalue;
508
509 ret = qemu_strtoi64(token->str, NULL, 10, &value);
510 if (!ret) {
511 return QOBJECT(qnum_from_int(value));
512 }
513 assert(ret == -ERANGE);
514
515 if (token->str[0] != '-') {
516 ret = qemu_strtou64(token->str, NULL, 10, &uvalue);
517 if (!ret) {
518 return QOBJECT(qnum_from_uint(uvalue));
519 }
520 assert(ret == -ERANGE);
521 }
522 }
523 /* fall through to JSON_FLOAT */
524 case JSON_FLOAT:
525 /* FIXME dependent on locale; a pervasive issue in QEMU */
526 /* FIXME our lexer matches RFC 8259 in forbidding Inf or NaN,
527 * but those might be useful extensions beyond JSON */
528 return QOBJECT(qnum_from_double(strtod(token->str, NULL)));
529 default:
530 abort();
531 }
532 }
533
534 static QObject *parse_value(JSONParserContext *ctxt)
535 {
536 JSONToken *token;
537
538 token = parser_context_peek_token(ctxt);
539 if (token == NULL) {
540 parse_error(ctxt, NULL, "premature EOI");
541 return NULL;
542 }
543
544 switch (token->type) {
545 case JSON_LCURLY:
546 return parse_object(ctxt);
547 case JSON_LSQUARE:
548 return parse_array(ctxt);
549 case JSON_INTERP:
550 return parse_interpolation(ctxt);
551 case JSON_INTEGER:
552 case JSON_FLOAT:
553 case JSON_STRING:
554 return parse_literal(ctxt);
555 case JSON_KEYWORD:
556 return parse_keyword(ctxt);
557 default:
558 parse_error(ctxt, token, "expecting value");
559 return NULL;
560 }
561 }
562
563 JSONToken *json_token(JSONTokenType type, int x, int y, GString *tokstr)
564 {
565 JSONToken *token = g_malloc(sizeof(JSONToken) + tokstr->len + 1);
566
567 token->type = type;
568 memcpy(token->str, tokstr->str, tokstr->len);
569 token->str[tokstr->len] = 0;
570 token->x = x;
571 token->y = y;
572 return token;
573 }
574
575 QObject *json_parser_parse(GQueue *tokens, va_list *ap, Error **errp)
576 {
577 JSONParserContext ctxt = { .buf = tokens, .ap = ap };
578 QObject *result;
579
580 result = parse_value(&ctxt);
581 assert(ctxt.err || g_queue_is_empty(ctxt.buf));
582
583 error_propagate(errp, ctxt.err);
584
585 while (!g_queue_is_empty(ctxt.buf)) {
586 parser_context_pop_token(&ctxt);
587 }
588 g_free(ctxt.current);
589
590 return result;
591 }