]>
Commit | Line | Data |
---|---|---|
5ab8558d AL |
1 | /* |
2 | * JSON lexer | |
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 | ||
f2ad72b3 | 14 | #include "qemu/osdep.h" |
5ab8558d | 15 | #include "qemu-common.h" |
7b1b5d19 | 16 | #include "qapi/qmp/json-lexer.h" |
5ab8558d | 17 | |
325601b4 AL |
18 | #define MAX_TOKEN_SIZE (64ULL << 20) |
19 | ||
5ab8558d | 20 | /* |
ff5394ad EB |
21 | * Required by JSON (RFC 7159): |
22 | * | |
23 | * \"([^\\\"]|\\[\"'\\/bfnrt]|\\u[0-9a-fA-F]{4})*\" | |
24 | * -?(0|[1-9][0-9]*)(.[0-9]+)?([eE][-+]?[0-9]+)? | |
5ab8558d | 25 | * [{}\[\],:] |
ff5394ad EB |
26 | * [a-z]+ # covers null, true, false |
27 | * | |
28 | * Extension of '' strings: | |
29 | * | |
30 | * '([^\\']|\\[\"'\\/bfnrt]|\\u[0-9a-fA-F]{4})*' | |
31 | * | |
32 | * Extension for vararg handling in JSON construction: | |
33 | * | |
34 | * %((l|ll|I64)?d|[ipsf]) | |
5ab8558d AL |
35 | * |
36 | */ | |
37 | ||
38 | enum json_lexer_state { | |
b8d3b1da | 39 | IN_ERROR = 0, /* must really be 0, see json_lexer[] */ |
5ab8558d AL |
40 | IN_DQ_UCODE3, |
41 | IN_DQ_UCODE2, | |
42 | IN_DQ_UCODE1, | |
43 | IN_DQ_UCODE0, | |
44 | IN_DQ_STRING_ESCAPE, | |
45 | IN_DQ_STRING, | |
46 | IN_SQ_UCODE3, | |
47 | IN_SQ_UCODE2, | |
48 | IN_SQ_UCODE1, | |
49 | IN_SQ_UCODE0, | |
50 | IN_SQ_STRING_ESCAPE, | |
51 | IN_SQ_STRING, | |
52 | IN_ZERO, | |
53 | IN_DIGITS, | |
54 | IN_DIGIT, | |
55 | IN_EXP_E, | |
56 | IN_MANTISSA, | |
57 | IN_MANTISSA_DIGITS, | |
58 | IN_NONZERO_NUMBER, | |
59 | IN_NEG_NONZERO_NUMBER, | |
60 | IN_KEYWORD, | |
61 | IN_ESCAPE, | |
62 | IN_ESCAPE_L, | |
63 | IN_ESCAPE_LL, | |
2c0d4b36 RT |
64 | IN_ESCAPE_I, |
65 | IN_ESCAPE_I6, | |
66 | IN_ESCAPE_I64, | |
5ab8558d | 67 | IN_WHITESPACE, |
5ab8558d AL |
68 | IN_START, |
69 | }; | |
70 | ||
b8d3b1da MA |
71 | QEMU_BUILD_BUG_ON((int)JSON_MIN <= (int)IN_START); |
72 | ||
5ab8558d AL |
73 | #define TERMINAL(state) [0 ... 0x7F] = (state) |
74 | ||
f7c05274 PB |
75 | /* Return whether TERMINAL is a terminal state and the transition to it |
76 | from OLD_STATE required lookahead. This happens whenever the table | |
77 | below uses the TERMINAL macro. */ | |
78 | #define TERMINAL_NEEDED_LOOKAHEAD(old_state, terminal) \ | |
79 | (json_lexer[(old_state)][0] == (terminal)) | |
80 | ||
5ab8558d | 81 | static const uint8_t json_lexer[][256] = { |
b8d3b1da MA |
82 | /* Relies on default initialization to IN_ERROR! */ |
83 | ||
5ab8558d AL |
84 | /* double quote string */ |
85 | [IN_DQ_UCODE3] = { | |
86 | ['0' ... '9'] = IN_DQ_STRING, | |
87 | ['a' ... 'f'] = IN_DQ_STRING, | |
88 | ['A' ... 'F'] = IN_DQ_STRING, | |
89 | }, | |
90 | [IN_DQ_UCODE2] = { | |
91 | ['0' ... '9'] = IN_DQ_UCODE3, | |
92 | ['a' ... 'f'] = IN_DQ_UCODE3, | |
93 | ['A' ... 'F'] = IN_DQ_UCODE3, | |
94 | }, | |
95 | [IN_DQ_UCODE1] = { | |
96 | ['0' ... '9'] = IN_DQ_UCODE2, | |
97 | ['a' ... 'f'] = IN_DQ_UCODE2, | |
98 | ['A' ... 'F'] = IN_DQ_UCODE2, | |
99 | }, | |
100 | [IN_DQ_UCODE0] = { | |
101 | ['0' ... '9'] = IN_DQ_UCODE1, | |
102 | ['a' ... 'f'] = IN_DQ_UCODE1, | |
103 | ['A' ... 'F'] = IN_DQ_UCODE1, | |
104 | }, | |
105 | [IN_DQ_STRING_ESCAPE] = { | |
106 | ['b'] = IN_DQ_STRING, | |
107 | ['f'] = IN_DQ_STRING, | |
108 | ['n'] = IN_DQ_STRING, | |
109 | ['r'] = IN_DQ_STRING, | |
110 | ['t'] = IN_DQ_STRING, | |
1041ba7a LC |
111 | ['/'] = IN_DQ_STRING, |
112 | ['\\'] = IN_DQ_STRING, | |
5ab8558d AL |
113 | ['\''] = IN_DQ_STRING, |
114 | ['\"'] = IN_DQ_STRING, | |
115 | ['u'] = IN_DQ_UCODE0, | |
116 | }, | |
117 | [IN_DQ_STRING] = { | |
b011f619 MR |
118 | [1 ... 0xBF] = IN_DQ_STRING, |
119 | [0xC2 ... 0xF4] = IN_DQ_STRING, | |
5ab8558d | 120 | ['\\'] = IN_DQ_STRING_ESCAPE, |
28e91a68 | 121 | ['"'] = JSON_STRING, |
5ab8558d AL |
122 | }, |
123 | ||
124 | /* single quote string */ | |
125 | [IN_SQ_UCODE3] = { | |
126 | ['0' ... '9'] = IN_SQ_STRING, | |
127 | ['a' ... 'f'] = IN_SQ_STRING, | |
128 | ['A' ... 'F'] = IN_SQ_STRING, | |
129 | }, | |
130 | [IN_SQ_UCODE2] = { | |
131 | ['0' ... '9'] = IN_SQ_UCODE3, | |
132 | ['a' ... 'f'] = IN_SQ_UCODE3, | |
133 | ['A' ... 'F'] = IN_SQ_UCODE3, | |
134 | }, | |
135 | [IN_SQ_UCODE1] = { | |
136 | ['0' ... '9'] = IN_SQ_UCODE2, | |
137 | ['a' ... 'f'] = IN_SQ_UCODE2, | |
138 | ['A' ... 'F'] = IN_SQ_UCODE2, | |
139 | }, | |
140 | [IN_SQ_UCODE0] = { | |
141 | ['0' ... '9'] = IN_SQ_UCODE1, | |
142 | ['a' ... 'f'] = IN_SQ_UCODE1, | |
143 | ['A' ... 'F'] = IN_SQ_UCODE1, | |
144 | }, | |
145 | [IN_SQ_STRING_ESCAPE] = { | |
146 | ['b'] = IN_SQ_STRING, | |
147 | ['f'] = IN_SQ_STRING, | |
148 | ['n'] = IN_SQ_STRING, | |
149 | ['r'] = IN_SQ_STRING, | |
150 | ['t'] = IN_SQ_STRING, | |
d5932334 PB |
151 | ['/'] = IN_SQ_STRING, |
152 | ['\\'] = IN_SQ_STRING, | |
5ab8558d AL |
153 | ['\''] = IN_SQ_STRING, |
154 | ['\"'] = IN_SQ_STRING, | |
155 | ['u'] = IN_SQ_UCODE0, | |
156 | }, | |
157 | [IN_SQ_STRING] = { | |
b011f619 MR |
158 | [1 ... 0xBF] = IN_SQ_STRING, |
159 | [0xC2 ... 0xF4] = IN_SQ_STRING, | |
5ab8558d | 160 | ['\\'] = IN_SQ_STRING_ESCAPE, |
28e91a68 | 161 | ['\''] = JSON_STRING, |
5ab8558d AL |
162 | }, |
163 | ||
164 | /* Zero */ | |
165 | [IN_ZERO] = { | |
166 | TERMINAL(JSON_INTEGER), | |
33d05394 | 167 | ['0' ... '9'] = IN_ERROR, |
5ab8558d AL |
168 | ['.'] = IN_MANTISSA, |
169 | }, | |
170 | ||
171 | /* Float */ | |
172 | [IN_DIGITS] = { | |
173 | TERMINAL(JSON_FLOAT), | |
174 | ['0' ... '9'] = IN_DIGITS, | |
175 | }, | |
176 | ||
177 | [IN_DIGIT] = { | |
178 | ['0' ... '9'] = IN_DIGITS, | |
179 | }, | |
180 | ||
181 | [IN_EXP_E] = { | |
182 | ['-'] = IN_DIGIT, | |
183 | ['+'] = IN_DIGIT, | |
184 | ['0' ... '9'] = IN_DIGITS, | |
185 | }, | |
186 | ||
187 | [IN_MANTISSA_DIGITS] = { | |
188 | TERMINAL(JSON_FLOAT), | |
189 | ['0' ... '9'] = IN_MANTISSA_DIGITS, | |
190 | ['e'] = IN_EXP_E, | |
191 | ['E'] = IN_EXP_E, | |
192 | }, | |
193 | ||
194 | [IN_MANTISSA] = { | |
195 | ['0' ... '9'] = IN_MANTISSA_DIGITS, | |
196 | }, | |
197 | ||
198 | /* Number */ | |
199 | [IN_NONZERO_NUMBER] = { | |
200 | TERMINAL(JSON_INTEGER), | |
201 | ['0' ... '9'] = IN_NONZERO_NUMBER, | |
202 | ['e'] = IN_EXP_E, | |
203 | ['E'] = IN_EXP_E, | |
204 | ['.'] = IN_MANTISSA, | |
205 | }, | |
206 | ||
207 | [IN_NEG_NONZERO_NUMBER] = { | |
208 | ['0'] = IN_ZERO, | |
209 | ['1' ... '9'] = IN_NONZERO_NUMBER, | |
210 | }, | |
211 | ||
212 | /* keywords */ | |
213 | [IN_KEYWORD] = { | |
214 | TERMINAL(JSON_KEYWORD), | |
215 | ['a' ... 'z'] = IN_KEYWORD, | |
216 | }, | |
217 | ||
218 | /* whitespace */ | |
219 | [IN_WHITESPACE] = { | |
220 | TERMINAL(JSON_SKIP), | |
221 | [' '] = IN_WHITESPACE, | |
222 | ['\t'] = IN_WHITESPACE, | |
223 | ['\r'] = IN_WHITESPACE, | |
224 | ['\n'] = IN_WHITESPACE, | |
ff5394ad | 225 | }, |
5ab8558d | 226 | |
5ab8558d | 227 | /* escape */ |
5ab8558d | 228 | [IN_ESCAPE_LL] = { |
28e91a68 | 229 | ['d'] = JSON_ESCAPE, |
5ab8558d AL |
230 | }, |
231 | ||
232 | [IN_ESCAPE_L] = { | |
28e91a68 | 233 | ['d'] = JSON_ESCAPE, |
5ab8558d AL |
234 | ['l'] = IN_ESCAPE_LL, |
235 | }, | |
236 | ||
2c0d4b36 | 237 | [IN_ESCAPE_I64] = { |
28e91a68 | 238 | ['d'] = JSON_ESCAPE, |
2c0d4b36 RT |
239 | }, |
240 | ||
241 | [IN_ESCAPE_I6] = { | |
242 | ['4'] = IN_ESCAPE_I64, | |
243 | }, | |
244 | ||
245 | [IN_ESCAPE_I] = { | |
246 | ['6'] = IN_ESCAPE_I6, | |
247 | }, | |
248 | ||
5ab8558d | 249 | [IN_ESCAPE] = { |
28e91a68 PB |
250 | ['d'] = JSON_ESCAPE, |
251 | ['i'] = JSON_ESCAPE, | |
252 | ['p'] = JSON_ESCAPE, | |
253 | ['s'] = JSON_ESCAPE, | |
254 | ['f'] = JSON_ESCAPE, | |
5ab8558d | 255 | ['l'] = IN_ESCAPE_L, |
2c0d4b36 | 256 | ['I'] = IN_ESCAPE_I, |
5ab8558d AL |
257 | }, |
258 | ||
259 | /* top level rule */ | |
260 | [IN_START] = { | |
261 | ['"'] = IN_DQ_STRING, | |
262 | ['\''] = IN_SQ_STRING, | |
263 | ['0'] = IN_ZERO, | |
264 | ['1' ... '9'] = IN_NONZERO_NUMBER, | |
265 | ['-'] = IN_NEG_NONZERO_NUMBER, | |
c5461660 MA |
266 | ['{'] = JSON_LCURLY, |
267 | ['}'] = JSON_RCURLY, | |
268 | ['['] = JSON_LSQUARE, | |
269 | [']'] = JSON_RSQUARE, | |
270 | [','] = JSON_COMMA, | |
271 | [':'] = JSON_COLON, | |
5ab8558d AL |
272 | ['a' ... 'z'] = IN_KEYWORD, |
273 | ['%'] = IN_ESCAPE, | |
274 | [' '] = IN_WHITESPACE, | |
275 | ['\t'] = IN_WHITESPACE, | |
276 | ['\r'] = IN_WHITESPACE, | |
277 | ['\n'] = IN_WHITESPACE, | |
278 | }, | |
279 | }; | |
280 | ||
281 | void json_lexer_init(JSONLexer *lexer, JSONLexerEmitter func) | |
282 | { | |
283 | lexer->emit = func; | |
284 | lexer->state = IN_START; | |
d2ca7c0b | 285 | lexer->token = g_string_sized_new(3); |
03308f6c | 286 | lexer->x = lexer->y = 0; |
5ab8558d AL |
287 | } |
288 | ||
bd3924a3 | 289 | static int json_lexer_feed_char(JSONLexer *lexer, char ch, bool flush) |
5ab8558d | 290 | { |
f7c05274 PB |
291 | int char_consumed, new_state; |
292 | ||
5ab8558d AL |
293 | lexer->x++; |
294 | if (ch == '\n') { | |
295 | lexer->x = 0; | |
296 | lexer->y++; | |
297 | } | |
298 | ||
f7c05274 | 299 | do { |
b8d3b1da | 300 | assert(lexer->state <= ARRAY_SIZE(json_lexer)); |
f7c05274 PB |
301 | new_state = json_lexer[lexer->state][(uint8_t)ch]; |
302 | char_consumed = !TERMINAL_NEEDED_LOOKAHEAD(lexer->state, new_state); | |
303 | if (char_consumed) { | |
d2ca7c0b | 304 | g_string_append_c(lexer->token, ch); |
f7c05274 | 305 | } |
5ab8558d | 306 | |
f7c05274 | 307 | switch (new_state) { |
c5461660 MA |
308 | case JSON_LCURLY: |
309 | case JSON_RCURLY: | |
310 | case JSON_LSQUARE: | |
311 | case JSON_RSQUARE: | |
312 | case JSON_COLON: | |
313 | case JSON_COMMA: | |
f7c05274 PB |
314 | case JSON_ESCAPE: |
315 | case JSON_INTEGER: | |
316 | case JSON_FLOAT: | |
317 | case JSON_KEYWORD: | |
318 | case JSON_STRING: | |
319 | lexer->emit(lexer, lexer->token, new_state, lexer->x, lexer->y); | |
0b0404bf | 320 | /* fall through */ |
f7c05274 | 321 | case JSON_SKIP: |
d2ca7c0b | 322 | g_string_truncate(lexer->token, 0); |
f7c05274 PB |
323 | new_state = IN_START; |
324 | break; | |
33d05394 | 325 | case IN_ERROR: |
b011f619 MR |
326 | /* XXX: To avoid having previous bad input leaving the parser in an |
327 | * unresponsive state where we consume unpredictable amounts of | |
328 | * subsequent "good" input, percolate this error state up to the | |
329 | * tokenizer/parser by forcing a NULL object to be emitted, then | |
330 | * reset state. | |
331 | * | |
332 | * Also note that this handling is required for reliable channel | |
333 | * negotiation between QMP and the guest agent, since chr(0xFF) | |
334 | * is placed at the beginning of certain events to ensure proper | |
335 | * delivery when the channel is in an unknown state. chr(0xFF) is | |
336 | * never a valid ASCII/UTF-8 sequence, so this should reliably | |
337 | * induce an error/flush state. | |
338 | */ | |
339 | lexer->emit(lexer, lexer->token, JSON_ERROR, lexer->x, lexer->y); | |
d2ca7c0b | 340 | g_string_truncate(lexer->token, 0); |
529a0ef5 | 341 | new_state = IN_START; |
b011f619 MR |
342 | lexer->state = new_state; |
343 | return 0; | |
f7c05274 PB |
344 | default: |
345 | break; | |
346 | } | |
347 | lexer->state = new_state; | |
bd3924a3 | 348 | } while (!char_consumed && !flush); |
325601b4 AL |
349 | |
350 | /* Do not let a single token grow to an arbitrarily large size, | |
351 | * this is a security consideration. | |
352 | */ | |
d2ca7c0b | 353 | if (lexer->token->len > MAX_TOKEN_SIZE) { |
325601b4 | 354 | lexer->emit(lexer, lexer->token, lexer->state, lexer->x, lexer->y); |
d2ca7c0b | 355 | g_string_truncate(lexer->token, 0); |
325601b4 AL |
356 | lexer->state = IN_START; |
357 | } | |
358 | ||
5ab8558d AL |
359 | return 0; |
360 | } | |
361 | ||
362 | int json_lexer_feed(JSONLexer *lexer, const char *buffer, size_t size) | |
363 | { | |
364 | size_t i; | |
365 | ||
366 | for (i = 0; i < size; i++) { | |
367 | int err; | |
368 | ||
bd3924a3 | 369 | err = json_lexer_feed_char(lexer, buffer[i], false); |
5ab8558d AL |
370 | if (err < 0) { |
371 | return err; | |
372 | } | |
373 | } | |
374 | ||
375 | return 0; | |
376 | } | |
377 | ||
378 | int json_lexer_flush(JSONLexer *lexer) | |
379 | { | |
b011f619 | 380 | return lexer->state == IN_START ? 0 : json_lexer_feed_char(lexer, 0, true); |
5ab8558d AL |
381 | } |
382 | ||
383 | void json_lexer_destroy(JSONLexer *lexer) | |
384 | { | |
d2ca7c0b | 385 | g_string_free(lexer->token, true); |
5ab8558d | 386 | } |