qemu/json-streamer.c

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/*
* JSON streaming support
*
* Copyright IBM, Corp. 2009
*
* Authors:
* Anthony Liguori <aliguori@us.ibm.com>
*
* This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
* See the COPYING.LIB file in the top-level directory.
*
*/
#include "qapi/qmp/qlist.h"
#include "qapi/qmp/qint.h"
#include "qapi/qmp/qdict.h"
#include "qemu-common.h"
#include "qapi/qmp/json-lexer.h"
#include "qapi/qmp/json-streamer.h"
#define MAX_TOKEN_SIZE (64ULL << 20)
#define MAX_NESTING (1ULL << 10)
static void json_message_process_token(JSONLexer *lexer, QString *token, JSONTokenType type, int x, int y)
{
JSONMessageParser *parser = container_of(lexer, JSONMessageParser, lexer);
QDict *dict;
if (type == JSON_OPERATOR) {
switch (qstring_get_str(token)[0]) {
case '{':
parser->brace_count++;
break;
case '}':
parser->brace_count--;
break;
case '[':
parser->bracket_count++;
break;
case ']':
parser->bracket_count--;
break;
default:
break;
}
}
dict = qdict_new();
qdict_put(dict, "type", qint_from_int(type));
QINCREF(token);
qdict_put(dict, "token", token);
qdict_put(dict, "x", qint_from_int(x));
qdict_put(dict, "y", qint_from_int(y));
parser->token_size += token->length;
qlist_append(parser->tokens, dict);
if (type == JSON_ERROR) {
goto out_emit_bad;
} else if (parser->brace_count < 0 ||
parser->bracket_count < 0 ||
(parser->brace_count == 0 &&
parser->bracket_count == 0)) {
goto out_emit;
} else if (parser->token_size > MAX_TOKEN_SIZE ||
parser->bracket_count > MAX_NESTING ||
parser->brace_count > MAX_NESTING) {
/* Security consideration, we limit total memory allocated per object
* and the maximum recursion depth that a message can force.
*/
goto out_emit;
}
return;
out_emit_bad:
/* clear out token list and tell the parser to emit and error
* indication by passing it a NULL list
*/
QDECREF(parser->tokens);
parser->tokens = NULL;
out_emit:
/* send current list of tokens to parser and reset tokenizer */
parser->brace_count = 0;
parser->bracket_count = 0;
parser->emit(parser, parser->tokens);
if (parser->tokens) {
QDECREF(parser->tokens);
}
parser->tokens = qlist_new();
parser->token_size = 0;
}
void json_message_parser_init(JSONMessageParser *parser,
void (*func)(JSONMessageParser *, QList *))
{
parser->emit = func;
parser->brace_count = 0;
parser->bracket_count = 0;
parser->tokens = qlist_new();
parser->token_size = 0;
json_lexer_init(&parser->lexer, json_message_process_token);
}
int json_message_parser_feed(JSONMessageParser *parser,
const char *buffer, size_t size)
{
return json_lexer_feed(&parser->lexer, buffer, size);
}
int json_message_parser_flush(JSONMessageParser *parser)
{
return json_lexer_flush(&parser->lexer);
}
void json_message_parser_destroy(JSONMessageParser *parser)
{
json_lexer_destroy(&parser->lexer);
QDECREF(parser->tokens);
}