Re: [Qemu-devel] [PATCH v2 12/18] qjson: return parsing error if unterminated input

[Markus Armbruster]

Marc-André Lureau <address@hidden> writes:

> Signed-off-by: Marc-André Lureau <address@hidden>
> ---
>  qobject/json-streamer.c | 4 +++-
>  qobject/qjson.c         | 5 ++++-
>  tests/check-qjson.c     | 8 ++++----
>  3 files changed, 11 insertions(+), 6 deletions(-)
>
> diff --git a/qobject/json-streamer.c b/qobject/json-streamer.c
> index c51c2021f9..065c551332 100644
> --- a/qobject/json-streamer.c
> +++ b/qobject/json-streamer.c
> @@ -126,7 +126,9 @@ int json_message_parser_feed(JSONMessageParser *parser,
>  
>  int json_message_parser_flush(JSONMessageParser *parser)
>  {
> -    return json_lexer_flush(&parser->lexer);
> +    int ret = json_lexer_flush(&parser->lexer);
> +
> +    return ret ?: g_queue_get_length(parser->tokens);
>  }
>  
>  void json_message_parser_destroy(JSONMessageParser *parser)
> diff --git a/qobject/qjson.c b/qobject/qjson.c
> index 01218c9ad6..8afdc1e06a 100644
> --- a/qobject/qjson.c
> +++ b/qobject/qjson.c
> @@ -64,7 +64,10 @@ QObject *qobject_from_jsonv(const char *string, va_list 
> *ap, Error **errp)
>  
>      json_message_parser_init(&state.parser, parse_json);
>      json_message_parser_feed(&state.parser, string, strlen(string));
> -    json_message_parser_flush(&state.parser);
> +    if (json_message_parser_flush(&state.parser) != 0 &&
> +        !state.err) {
> +        error_setg(&state.err, QERR_JSON_PARSING);
> +    }
>      json_message_parser_destroy(&state.parser);
>  
>      error_propagate(errp, state.err);

Again, this leaves other users broken.  Reproducer for QMP:

    $ echo -e '{ "execute": "qmp_capabilities" }\n{ "execute": "query-name" 
}\n[' | socat UNIX:/work/armbru/images/test-qmp STDIO
    {"QMP": {"version": {"qemu": {"micro": 90, "minor": 12, "major": 2}, 
"package": "v3.0.0-rc1-21-g975ad3dcf2"}, "capabilities": ["oob"]}}
    {"return": {}}
    {"return": {}}

Note there's no error reported for the last line.

The simplification of the JSON parser I have in mind might make this
easy to fix properly.  I'll look into it.