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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 "qemu/osdep.h"
#include "qapi/error.h"
#include "qapi/qmp/json-lexer.h"
#include "qapi/qmp/json-parser.h"
#include "qapi/qmp/json-streamer.h"
#define MAX_TOKEN_SIZE (64ULL << 20)
#define MAX_TOKEN_COUNT (2ULL << 20)
#define MAX_NESTING (1 << 10)
static void json_message_free_tokens(JSONMessageParser *parser)
{
JSONToken *token;
while ((token = g_queue_pop_head(&parser->tokens))) {
g_free(token);
}
}
void json_message_process_token(JSONLexer *lexer, GString *input,
JSONTokenType type, int x, int y)
{
JSONMessageParser *parser = container_of(lexer, JSONMessageParser, lexer);
QObject *json = NULL;
Error *err = NULL;
JSONToken *token;
switch (type) {
case JSON_LCURLY:
parser->brace_count++;
break;
case JSON_RCURLY:
parser->brace_count--;
break;
case JSON_LSQUARE:
parser->bracket_count++;
break;
case JSON_RSQUARE:
parser->bracket_count--;
break;
case JSON_ERROR:
error_setg(&err, "JSON parse error, stray '%s'", input->str);
goto out_emit;
case JSON_END_OF_INPUT:
if (g_queue_is_empty(&parser->tokens)) {
return;
}
json = json_parser_parse(&parser->tokens, parser->ap, &err);
goto out_emit;
default:
break;
}
/*
* Security consideration, we limit total memory allocated per object
* and the maximum recursion depth that a message can force.
*/
if (parser->token_size + input->len + 1 > MAX_TOKEN_SIZE) {
error_setg(&err, "JSON token size limit exceeded");
goto out_emit;
}
if (g_queue_get_length(&parser->tokens) + 1 > MAX_TOKEN_COUNT) {
error_setg(&err, "JSON token count limit exceeded");
goto out_emit;
}
if (parser->bracket_count + parser->brace_count > MAX_NESTING) {
error_setg(&err, "JSON nesting depth limit exceeded");
goto out_emit;
}
token = json_token(type, x, y, input);
parser->token_size += input->len;
g_queue_push_tail(&parser->tokens, token);
if ((parser->brace_count > 0 || parser->bracket_count > 0)
&& parser->bracket_count >= 0 && parser->bracket_count >= 0) {
return;
}
json = json_parser_parse(&parser->tokens, parser->ap, &err);
out_emit:
parser->brace_count = 0;
parser->bracket_count = 0;
json_message_free_tokens(parser);
parser->token_size = 0;
parser->emit(parser->opaque, json, err);
}
void json_message_parser_init(JSONMessageParser *parser,
void (*emit)(void *opaque, QObject *json,
Error *err),
void *opaque, va_list *ap)
{
parser->emit = emit;
parser->opaque = opaque;
parser->ap = ap;
parser->brace_count = 0;
parser->bracket_count = 0;
g_queue_init(&parser->tokens);
parser->token_size = 0;
json_lexer_init(&parser->lexer, !!ap);
}
void json_message_parser_feed(JSONMessageParser *parser,
const char *buffer, size_t size)
{
json_lexer_feed(&parser->lexer, buffer, size);
}
void json_message_parser_flush(JSONMessageParser *parser)
{
json_lexer_flush(&parser->lexer);
assert(g_queue_is_empty(&parser->tokens));
}
void json_message_parser_destroy(JSONMessageParser *parser)
{
json_lexer_destroy(&parser->lexer);
json_message_free_tokens(parser);
}
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