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Anthony Liguorid7ff3ac2009-11-11 10:38:59 -06001/*
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
Peter Maydellf2ad72b2016-01-29 17:50:01 +000014#include "qemu/osdep.h"
Anthony Liguorid7ff3ac2009-11-11 10:38:59 -060015#include "qemu-common.h"
Paolo Bonzini7b1b5d12012-12-17 18:19:43 +010016#include "qapi/qmp/json-lexer.h"
17#include "qapi/qmp/json-streamer.h"
Anthony Liguorid7ff3ac2009-11-11 10:38:59 -060018
Anthony Liguori29c75dd2011-06-01 12:14:53 -050019#define MAX_TOKEN_SIZE (64ULL << 20)
Markus Armbrusterdf649832015-11-25 22:23:33 +010020#define MAX_TOKEN_COUNT (2ULL << 20)
Anthony Liguori29c75dd2011-06-01 12:14:53 -050021#define MAX_NESTING (1ULL << 10)
22
Eric Blakeba4dba52016-05-18 15:46:52 -060023static void json_message_free_token(void *token, void *opaque)
24{
25 g_free(token);
26}
27
Paolo Bonzini95385fe2015-11-25 22:23:31 +010028static void json_message_free_tokens(JSONMessageParser *parser)
29{
30 if (parser->tokens) {
Eric Blakeba4dba52016-05-18 15:46:52 -060031 g_queue_foreach(parser->tokens, json_message_free_token, NULL);
Paolo Bonzini95385fe2015-11-25 22:23:31 +010032 g_queue_free(parser->tokens);
33 parser->tokens = NULL;
34 }
35}
36
Paolo Bonzinid2ca7c02015-11-25 22:23:29 +010037static void json_message_process_token(JSONLexer *lexer, GString *input,
38 JSONTokenType type, int x, int y)
Anthony Liguorid7ff3ac2009-11-11 10:38:59 -060039{
40 JSONMessageParser *parser = container_of(lexer, JSONMessageParser, lexer);
Paolo Bonzini9bada892015-11-25 22:23:32 +010041 JSONToken *token;
Paolo Bonzinia942d8f2016-07-04 14:40:59 +020042 GQueue *tokens;
Anthony Liguorid7ff3ac2009-11-11 10:38:59 -060043
Markus Armbrusterc5461662015-11-25 22:23:26 +010044 switch (type) {
45 case JSON_LCURLY:
46 parser->brace_count++;
47 break;
48 case JSON_RCURLY:
49 parser->brace_count--;
50 break;
51 case JSON_LSQUARE:
52 parser->bracket_count++;
53 break;
54 case JSON_RSQUARE:
55 parser->bracket_count--;
56 break;
57 default:
58 break;
Anthony Liguorid7ff3ac2009-11-11 10:38:59 -060059 }
60
Paolo Bonzini9bada892015-11-25 22:23:32 +010061 token = g_malloc(sizeof(JSONToken) + input->len + 1);
62 token->type = type;
63 memcpy(token->str, input->str, input->len);
64 token->str[input->len] = 0;
65 token->x = x;
66 token->y = y;
Anthony Liguorid7ff3ac2009-11-11 10:38:59 -060067
Paolo Bonzinid2ca7c02015-11-25 22:23:29 +010068 parser->token_size += input->len;
Anthony Liguori29c75dd2011-06-01 12:14:53 -050069
Paolo Bonzini9bada892015-11-25 22:23:32 +010070 g_queue_push_tail(parser->tokens, token);
Anthony Liguorid7ff3ac2009-11-11 10:38:59 -060071
Michael Roth5e2dafe2011-06-01 12:14:59 -050072 if (type == JSON_ERROR) {
73 goto out_emit_bad;
74 } else if (parser->brace_count < 0 ||
Anthony Liguori55f83012011-06-01 12:14:51 -050075 parser->bracket_count < 0 ||
76 (parser->brace_count == 0 &&
77 parser->bracket_count == 0)) {
Michael Roth5e2dafe2011-06-01 12:14:59 -050078 goto out_emit;
Anthony Liguori29c75dd2011-06-01 12:14:53 -050079 } else if (parser->token_size > MAX_TOKEN_SIZE ||
Markus Armbrusterdf649832015-11-25 22:23:33 +010080 g_queue_get_length(parser->tokens) > MAX_TOKEN_COUNT ||
Markus Armbruster4f2d31f2015-11-25 22:23:22 +010081 parser->bracket_count + parser->brace_count > MAX_NESTING) {
Anthony Liguori29c75dd2011-06-01 12:14:53 -050082 /* Security consideration, we limit total memory allocated per object
83 * and the maximum recursion depth that a message can force.
84 */
Markus Armbruster07531132015-11-25 22:23:23 +010085 goto out_emit_bad;
Anthony Liguorid7ff3ac2009-11-11 10:38:59 -060086 }
Michael Roth5e2dafe2011-06-01 12:14:59 -050087
88 return;
89
90out_emit_bad:
Markus Armbruster07531132015-11-25 22:23:23 +010091 /*
92 * Clear out token list and tell the parser to emit an error
Michael Roth5e2dafe2011-06-01 12:14:59 -050093 * indication by passing it a NULL list
94 */
Paolo Bonzini95385fe2015-11-25 22:23:31 +010095 json_message_free_tokens(parser);
Michael Roth5e2dafe2011-06-01 12:14:59 -050096out_emit:
97 /* send current list of tokens to parser and reset tokenizer */
98 parser->brace_count = 0;
99 parser->bracket_count = 0;
Paolo Bonzinia942d8f2016-07-04 14:40:59 +0200100 /* parser->emit takes ownership of parser->tokens. Remove our own
101 * reference to parser->tokens before handing it out to parser->emit.
102 */
103 tokens = parser->tokens;
Paolo Bonzini95385fe2015-11-25 22:23:31 +0100104 parser->tokens = g_queue_new();
Paolo Bonzinia942d8f2016-07-04 14:40:59 +0200105 parser->emit(parser, tokens);
Michael Roth5e2dafe2011-06-01 12:14:59 -0500106 parser->token_size = 0;
Anthony Liguorid7ff3ac2009-11-11 10:38:59 -0600107}
108
109void json_message_parser_init(JSONMessageParser *parser,
Paolo Bonzini95385fe2015-11-25 22:23:31 +0100110 void (*func)(JSONMessageParser *, GQueue *))
Anthony Liguorid7ff3ac2009-11-11 10:38:59 -0600111{
112 parser->emit = func;
113 parser->brace_count = 0;
114 parser->bracket_count = 0;
Paolo Bonzini95385fe2015-11-25 22:23:31 +0100115 parser->tokens = g_queue_new();
Anthony Liguori29c75dd2011-06-01 12:14:53 -0500116 parser->token_size = 0;
Anthony Liguorid7ff3ac2009-11-11 10:38:59 -0600117
118 json_lexer_init(&parser->lexer, json_message_process_token);
119}
120
121int json_message_parser_feed(JSONMessageParser *parser,
122 const char *buffer, size_t size)
123{
124 return json_lexer_feed(&parser->lexer, buffer, size);
125}
126
127int json_message_parser_flush(JSONMessageParser *parser)
128{
129 return json_lexer_flush(&parser->lexer);
130}
131
132void json_message_parser_destroy(JSONMessageParser *parser)
133{
134 json_lexer_destroy(&parser->lexer);
Paolo Bonzini95385fe2015-11-25 22:23:31 +0100135 json_message_free_tokens(parser);
Anthony Liguorid7ff3ac2009-11-11 10:38:59 -0600136}