Sorry again for the late reply. Was transfered to another project that don't use Libcurl.
Now a colleague is wondering whether the bug is corrected in newer releases of libcurl.

Can someone give me an answer?

Best regards
Ludwig

----------------------------------------
> From: zorkulus_at_hotmail.com
> To: curl-library_at_cool.haxx.se
> Subject: RE: Libcurl stops when sending lots of https messages
> Date: Tue, 1 Dec 2009 13:15:00 +0100
>
>
>
> Sorry for the late reply!
>
>>> Curl_socket_ready do return the correct value. Since openSSL want us to
>>> write information to the socket after a SSL_ERROR_WANT_WRITE error code it
>>> seems reasonable that Curl_socket_ready should return 2 (CURL_CSELECT_OUT).
>>> But Curl_readwrite only calls the recieve function if we have a readable
>>> socket. And therein lies the fault.
>>
>> Exactly.
>>
>> We need to separate what to wait for and what to do when the waited-for action
>> occurs since in this case the socket gets writable and we should still call
>> the read function to take care of it.
>>
>> When thinking about it, I think we also have the same error for SSH although
>> we may not yet have found a case where it becomes visible.
>>
>>> Insted of using the return value from the Curl_socket_ready (which isn't a
>>> good measure of determine what to do since both SSL_write and SSL_read might
>>> use both readable and writeable sockets during a renegotiation ) we need
>>> some other way of knowing what we are doing. But I don't really see an easy
>>> way of doing this.
>>
>> Curl_socket_ready() is a rather low-level function that needs to stay working
>> exactly like it does.
>>
>> I suggest we introduce a new internal struct member or two that allows the
>> protocol-specific parts to set a forced action to assume, and the
>> Curl_readwrite() function would then check that field first before it assumes
>> that the event implies a specific action.
>>
>> It could work in a way similar to this (throwing out a suggestion):
>>
>> Index: lib/transfer.c
>> ===================================================================
>> RCS file: /cvsroot/curl/curl/lib/transfer.c,v
>> retrieving revision 1.442
>> diff -u -r1.442 transfer.c
>> --- lib/transfer.c 12 Nov 2009 14:36:34 -0000 1.442
>> +++ lib/transfer.c 15 Nov 2009 14:28:12 -0000
>> @@ -1649,6 +1649,7 @@
>> curl_socket_t fd_read;
>> curl_socket_t fd_write;
>> int select_res = conn->cselect_bits;
>> + int act_data; /* how to act on the data */
>>
>> conn->cselect_bits = 0;
>>
>> @@ -1675,21 +1676,24 @@
>> return CURLE_SEND_ERROR;
>> }
>>
>> - /* We go ahead and do a read if we have a readable socket or if
>> - the stream was rewound (in which case we have data in a
>> - buffer) */
>> + /* We go ahead and do a read if we have a readable socket or if the stream
>> + was rewound (in which case we have data in a buffer) */
>> if((k->keepon & KEEP_RECV) &&
>> - ((select_res & CURL_CSELECT_IN) || conn->bits.stream_was_rewound)) {
>> + ((select_res & CURL_CSELECT_IN) || conn->bits.stream_was_rewound))
>> + act_data |= (conn->forcewrite?KEEP_SEND:KEEP_RECV);
>>
>> + /* If we still have writing to do, we check if we have a writable socket. */
>> + if((k->keepon & KEEP_SEND) && (select_res & CURL_CSELECT_OUT))
>> + act_data |= (conn->forceread?KEEP_RECV:KEEP_SEND);
>> +
>> + if(act_data & KEEP_RECV) {
>> result = readwrite_data(data, conn, k, &didwhat, done);
>> if(result || *done)
>> return result;
>> }
>>
>> - /* If we still have writing to do, we check if we have a writable socket. */
>> - if((k->keepon & KEEP_SEND) && (select_res & CURL_CSELECT_OUT)) {
>> + if(act_data & KEEP_SEND) {
>> /* write */
>> -
>> result = readwrite_upload(data, conn, k, &didwhat);
>> if(result)
>> return result;
>>
>> It shouldn't be too hard to adapt the SSL stuff to use this concept methinks.
>> What you others think?
>
> Well to me it seems like a possible solution. I will try it out as soon as I can.
> I't doesn't seem all that hard to make it work.
>
>>
>>> One way ( but a quite ugly way I would say ) of solving the problem is to
>>> solve the problem in the Curl_ossl_recv function by creating a loop until we
>>> don't have a SSL_ERROR_WANT_WRITE or SSL_ERROR_WANT_READ error code ( or
>>> until things times out ).
>>
>> We're already working hard to decrease the amount of blocking places within
>> the code and I think adding new blocks without very good reasons is a bad
>> idea. I much rather prefer we go the route I suggest above and polish it to
>> work...
>
> Well. I also prefer to cure the disease rather than remove the symtoms. I will try your
> fix and return the results to you in a couple of days.
>
>>
>> --
>>
>> / daniel.haxx.se
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Received on 2010-08-19