On Sun, Jul 7, 2019 at 4:46 PM Nick Couchman <nick.e.couch...@gmail.com>
wrote:
> Getting back to this after a while...
>
>
>> Right. You cannot have two parsers reading from the same socket, nor
>> should
>> protocol support be attempting to parse the Guacamole protocol manually.
>> To
>> handle argv, you need to provide an argv_handler to the guac_user struct.
>> That handler will be called when argv is received.
>>
>
> So, I've taken care of the issue of two parsers and am now correctly (I
> think) using the argv handler to process received argv instructions. I see
> the argv handler getting called, and it seems to process the correct
> setting name, but the data (argument value) doesn't actually seem to be
> there (empty or null). Not sure if I'm doing this incorrectly, but on the
> client side I'm doing the following:
>
> $log.debug('Sending response for parameter ' + parameter + ': ' +
> JSON.stringify(data[parameter]));
> var stream = client.createArgumentValueStream("string", parameter);
> var writer = new Guacamole.StringWriter(stream);
> writer.sendText(data[parameter]);
> writer.sendEnd();
> $log.debug('Finished sending response.');
>
> on the server side, like I said, I see the call to the argv handler that
> I've written, and it correctly choose the setting, but if I process the
> argv->buffer, it's empty??
>
Alright, scratch this - turns out my debugging was just wrong. Values are
arriving properly, so apparently something wrong with handling them...
>
> My admittedly very messy repos are here:
>
> https://github.com/necouchman/guacamole-client/tree/jira/221
> https://github.com/necouchman/guacamole-server/tree/jira/221
>
>
>
>>
>> This probably means that the use of the FreeRDP authentication callback
>> > will not work, unless
>> > there's some other way to accomplish this. I could still try to block
>> the
>> > pthread until the input is received, but this might cause other
>> problems on
>> > the client side with an unresponsive connection?
>> >
>>
>> If FreeRDP depends on this being synchronous, yes, the handler will need
>> to
>> block on some sort of pthread condition which is signalled when the
>> credentials are set. Reading of the argv instruction should happen
>> magically as long as argv_handler is properly set, as Guacamole protocol
>> parsing is handled for you by guacd and libguac in a separate thread.
>>
>> If blocking will potentially result in the connection going silent,
>> there's
>> a function for that - guac_socket_require_keep_alive():
>>
>>
>> http://guacamole.apache.org/doc/libguac/socket_8h.html#a1d8c5111a8234c7785ae23f379f7db03
>>
>> That will force the guac_socket to send a "nop" instruction roughly every
>> 5
>> seconds if nothing else is sent during that period.
>>
>
> I think I've managed to take care of this concern - I implemented a
> pthread_cond_timedwait() for each of the parameters that get requested, and
> then a pthread_cond_broadcast() within the argv handler to signal the
> completion. It's a little hard to tell if it's working properly with the
> issues I'm having with data not being sent, but during the prompt I see the
> nop debug messages on the server side, and the connection never times out,
> so I think it's waiting properly.
>
>
Apparently I haven't quite gotten this nailed down, yet - something with
handling the pthread condition isn't working right...
-Nick
>
