134 lines
3.6 KiB
C
134 lines
3.6 KiB
C
/*
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* JSON streaming support
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*
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* Copyright IBM, Corp. 2009
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*
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* Authors:
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* Anthony Liguori <aliguori@us.ibm.com>
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*
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* This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
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* See the COPYING.LIB file in the top-level directory.
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*
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*/
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#include "qemu/osdep.h"
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#include "qapi/error.h"
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#include "json-parser-int.h"
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#define MAX_TOKEN_SIZE (64ULL << 20)
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#define MAX_TOKEN_COUNT (2ULL << 20)
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#define MAX_NESTING (1 << 10)
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static void json_message_free_tokens(JSONMessageParser *parser)
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{
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JSONToken *token;
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while ((token = g_queue_pop_head(&parser->tokens))) {
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g_free(token);
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}
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}
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void json_message_process_token(JSONLexer *lexer, GString *input,
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JSONTokenType type, int x, int y)
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{
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JSONMessageParser *parser = container_of(lexer, JSONMessageParser, lexer);
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QObject *json = NULL;
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Error *err = NULL;
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JSONToken *token;
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switch (type) {
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case JSON_LCURLY:
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parser->brace_count++;
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break;
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case JSON_RCURLY:
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parser->brace_count--;
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break;
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case JSON_LSQUARE:
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parser->bracket_count++;
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break;
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case JSON_RSQUARE:
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parser->bracket_count--;
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break;
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case JSON_ERROR:
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error_setg(&err, "JSON parse error, stray '%s'", input->str);
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goto out_emit;
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case JSON_END_OF_INPUT:
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if (g_queue_is_empty(&parser->tokens)) {
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return;
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}
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json = json_parser_parse(&parser->tokens, parser->ap, &err);
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goto out_emit;
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default:
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break;
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}
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/*
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* Security consideration, we limit total memory allocated per object
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* and the maximum recursion depth that a message can force.
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*/
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if (parser->token_size + input->len + 1 > MAX_TOKEN_SIZE) {
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error_setg(&err, "JSON token size limit exceeded");
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goto out_emit;
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}
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if (g_queue_get_length(&parser->tokens) + 1 > MAX_TOKEN_COUNT) {
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error_setg(&err, "JSON token count limit exceeded");
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goto out_emit;
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}
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if (parser->bracket_count + parser->brace_count > MAX_NESTING) {
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error_setg(&err, "JSON nesting depth limit exceeded");
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goto out_emit;
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}
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token = json_token(type, x, y, input);
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parser->token_size += input->len;
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g_queue_push_tail(&parser->tokens, token);
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if ((parser->brace_count > 0 || parser->bracket_count > 0)
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&& parser->brace_count >= 0 && parser->bracket_count >= 0) {
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return;
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}
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json = json_parser_parse(&parser->tokens, parser->ap, &err);
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out_emit:
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parser->brace_count = 0;
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parser->bracket_count = 0;
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json_message_free_tokens(parser);
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parser->token_size = 0;
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parser->emit(parser->opaque, json, err);
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}
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void json_message_parser_init(JSONMessageParser *parser,
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void (*emit)(void *opaque, QObject *json,
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Error *err),
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void *opaque, va_list *ap)
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{
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parser->emit = emit;
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parser->opaque = opaque;
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parser->ap = ap;
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parser->brace_count = 0;
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parser->bracket_count = 0;
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g_queue_init(&parser->tokens);
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parser->token_size = 0;
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json_lexer_init(&parser->lexer, !!ap);
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}
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void json_message_parser_feed(JSONMessageParser *parser,
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const char *buffer, size_t size)
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{
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json_lexer_feed(&parser->lexer, buffer, size);
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}
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void json_message_parser_flush(JSONMessageParser *parser)
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{
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json_lexer_flush(&parser->lexer);
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assert(g_queue_is_empty(&parser->tokens));
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}
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void json_message_parser_destroy(JSONMessageParser *parser)
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{
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json_lexer_destroy(&parser->lexer);
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json_message_free_tokens(parser);
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}
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