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d7ff3acb AL |
1 | /* |
2 | * JSON streaming support | |
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 "qlist.h" | |
15 | #include "qint.h" | |
16 | #include "qdict.h" | |
17 | #include "qemu-common.h" | |
18 | #include "json-lexer.h" | |
19 | #include "json-streamer.h" | |
20 | ||
29c75ddd AL |
21 | #define MAX_TOKEN_SIZE (64ULL << 20) |
22 | #define MAX_NESTING (1ULL << 10) | |
23 | ||
d7ff3acb AL |
24 | static void json_message_process_token(JSONLexer *lexer, QString *token, JSONTokenType type, int x, int y) |
25 | { | |
26 | JSONMessageParser *parser = container_of(lexer, JSONMessageParser, lexer); | |
27 | QDict *dict; | |
28 | ||
29 | if (type == JSON_OPERATOR) { | |
30 | switch (qstring_get_str(token)[0]) { | |
31 | case '{': | |
32 | parser->brace_count++; | |
33 | break; | |
34 | case '}': | |
35 | parser->brace_count--; | |
36 | break; | |
37 | case '[': | |
38 | parser->bracket_count++; | |
39 | break; | |
40 | case ']': | |
41 | parser->bracket_count--; | |
42 | break; | |
43 | default: | |
44 | break; | |
45 | } | |
46 | } | |
47 | ||
48 | dict = qdict_new(); | |
2e89c068 | 49 | qdict_put(dict, "type", qint_from_int(type)); |
d7ff3acb | 50 | QINCREF(token); |
2e89c068 LC |
51 | qdict_put(dict, "token", token); |
52 | qdict_put(dict, "x", qint_from_int(x)); | |
53 | qdict_put(dict, "y", qint_from_int(y)); | |
d7ff3acb | 54 | |
29c75ddd AL |
55 | parser->token_size += token->length; |
56 | ||
d7ff3acb AL |
57 | qlist_append(parser->tokens, dict); |
58 | ||
5e2dafeb MR |
59 | if (type == JSON_ERROR) { |
60 | goto out_emit_bad; | |
61 | } else if (parser->brace_count < 0 || | |
55f8301f AL |
62 | parser->bracket_count < 0 || |
63 | (parser->brace_count == 0 && | |
64 | parser->bracket_count == 0)) { | |
5e2dafeb | 65 | goto out_emit; |
29c75ddd AL |
66 | } else if (parser->token_size > MAX_TOKEN_SIZE || |
67 | parser->bracket_count > MAX_NESTING || | |
68 | parser->brace_count > MAX_NESTING) { | |
69 | /* Security consideration, we limit total memory allocated per object | |
70 | * and the maximum recursion depth that a message can force. | |
71 | */ | |
5e2dafeb MR |
72 | goto out_emit; |
73 | } | |
74 | ||
75 | return; | |
76 | ||
77 | out_emit_bad: | |
78 | /* clear out token list and tell the parser to emit and error | |
79 | * indication by passing it a NULL list | |
80 | */ | |
81 | QDECREF(parser->tokens); | |
82 | parser->tokens = NULL; | |
83 | out_emit: | |
84 | /* send current list of tokens to parser and reset tokenizer */ | |
85 | parser->brace_count = 0; | |
86 | parser->bracket_count = 0; | |
87 | parser->emit(parser, parser->tokens); | |
88 | if (parser->tokens) { | |
29c75ddd | 89 | QDECREF(parser->tokens); |
d7ff3acb | 90 | } |
5e2dafeb MR |
91 | parser->tokens = qlist_new(); |
92 | parser->token_size = 0; | |
d7ff3acb AL |
93 | } |
94 | ||
95 | void json_message_parser_init(JSONMessageParser *parser, | |
96 | void (*func)(JSONMessageParser *, QList *)) | |
97 | { | |
98 | parser->emit = func; | |
99 | parser->brace_count = 0; | |
100 | parser->bracket_count = 0; | |
101 | parser->tokens = qlist_new(); | |
29c75ddd | 102 | parser->token_size = 0; |
d7ff3acb AL |
103 | |
104 | json_lexer_init(&parser->lexer, json_message_process_token); | |
105 | } | |
106 | ||
107 | int json_message_parser_feed(JSONMessageParser *parser, | |
108 | const char *buffer, size_t size) | |
109 | { | |
110 | return json_lexer_feed(&parser->lexer, buffer, size); | |
111 | } | |
112 | ||
113 | int json_message_parser_flush(JSONMessageParser *parser) | |
114 | { | |
115 | return json_lexer_flush(&parser->lexer); | |
116 | } | |
117 | ||
118 | void json_message_parser_destroy(JSONMessageParser *parser) | |
119 | { | |
120 | json_lexer_destroy(&parser->lexer); | |
121 | QDECREF(parser->tokens); | |
122 | } |