/* * JSON streaming support * * Copyright IBM, Corp. 2009 * * Authors: * Anthony Liguori * * 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 "qemu-common.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 (1ULL << 10) static void json_message_free_token(void *token, void *opaque) { g_free(token); } static void json_message_free_tokens(JSONMessageParser *parser) { if (parser->tokens) { g_queue_foreach(parser->tokens, json_message_free_token, NULL); g_queue_free(parser->tokens); parser->tokens = NULL; } } 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: goto out_emit; default: break; } token = g_malloc(sizeof(JSONToken) + input->len + 1); token->type = type; memcpy(token->str, input->str, input->len); token->str[input->len] = 0; token->x = x; token->y = y; parser->token_size += input->len; g_queue_push_tail(parser->tokens, token); if (parser->brace_count < 0 || parser->bracket_count < 0 || (parser->brace_count == 0 && parser->bracket_count == 0)) { json = json_parser_parse(parser->tokens, parser->ap, &err); parser->tokens = NULL; goto out_emit; } if (parser->token_size > MAX_TOKEN_SIZE || g_queue_get_length(parser->tokens) > MAX_TOKEN_COUNT || parser->bracket_count + 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: parser->brace_count = 0; parser->bracket_count = 0; json_message_free_tokens(parser); parser->tokens = g_queue_new(); 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; parser->tokens = g_queue_new(); 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); } void json_message_parser_destroy(JSONMessageParser *parser) { json_lexer_destroy(&parser->lexer); json_message_free_tokens(parser); }