dbmail-timsieved opening thousands of files (sockets) & syslog logging not working?

Hi.

I've been having some strange issues with dbmail-timsieved(3.1.17) lately:

every now and then I get errors like this in the log:
Sep 24 18:02:57 lordvan.com dbmail-timsieved[26837]: [0x190aa00]
Error:[server] _sock_cb(+582): 24:Too many open files

and several thousand of that per second. obviously that fills up my
/var/log which then causes things to crash.

I've been having a look at the logs & open files and noticed this:
for some reason i get a lot of connections which then result in "broken
pipe":

Sep 29 07:38:04 lordvan.com dbmail-timsieved[22749]: [0xb4ce00]
Notice:[server] server_run(+775): starting main service loop for [SIEVE]
Sep 29 07:38:04 lordvan.com dbmail-timsieved[22749]: [0xb4ce00]
Info:[server] server_set_sighandler(+693): signal handler placed
Sep 29 07:38:04 lordvan.com dbmail-timsieved[22749]: [0xb4ce00]
Debug:[server] dm_bind_and_listen(+403): creating plain socket [12] on
[0.0.0.0:2000]
Sep 29 07:38:04 lordvan.com dbmail-timsieved[22749]: [0xb4ce00]
Debug:[server] server_run(+813): Adding event for plain socket [12] [1/1]
Sep 29 07:38:04 lordvan.com dbmail-timsieved[22749]: [0xb4ce00]
Debug:[server] server_run(+840): dispatching event loop...
Sep 29 07:39:05 lordvan.com dbmail-timsieved[22749]: [0xb4ce00]
Info:[server] _sock_cb(+626): connection accepted
Sep 29 07:39:05 lordvan.com dbmail-timsieved[22749]: [0xb4ce00]
Notice:[clientbase] client_init(+184): incoming connection on
[127.0.0.1:2000] from [127.0.0.1:53686]
Sep 29 07:39:05 lordvan.com dbmail-timsieved[22749]: [0xb4ce00]
Debug:[misc] create_unique_id(+125): created:
221ac121020da73abe25612dc6045134
Sep 29 07:39:05 lordvan.com dbmail-timsieved[22749]: [0xb4ce00]
Debug:[clientbase] ci_cork(+205): [0x7f47eba47010]
Sep 29 07:39:05 lordvan.com dbmail-timsieved[22749]: [0xb4ce00]
Debug:[clientbase] ci_write(+343): [0x7f47eba47010] S >
[43/43:"IMPLEMENTATION" "DBMail timsieved 0.9.]
Sep 29 07:39:05 lordvan.com dbmail-timsieved[22749]: [0xb4ce00]
Debug:[clientbase] client_error_cb(+127): [0x7f47eba47010] fd [14]
Broken pipe[32], 0x7f47eba47010
Sep 29 07:39:05 lordvan.com dbmail-timsieved[22749]: [0xb4ce00]
Debug:[clientbase] ci_uncork(+212): [0x7f47eba47010]
Sep 29 07:39:05 lordvan.com dbmail-timsieved[22749]: [0xb4ce00]
Debug:[server] server_sig_cb(+651): fd 13, event 8, Broken pipe
Sep 29 07:40:05 lordvan.com dbmail-timsieved[22749]: [0xb4ce00]
Info:[server] _sock_cb(+626): connection accepted
Sep 29 07:40:05 lordvan.com dbmail-timsieved[22749]: [0xb4ce00]
Notice:[clientbase] client_init(+184): incoming connection on
[127.0.0.1:2000] from [127.0.0.1:53695]
Sep 29 07:40:05 lordvan.com dbmail-timsieved[22749]: [0xb4ce00]
Debug:[misc] create_unique_id(+125): created:
bdca0cd5314b84f941c7ea1bd1b23bb3
Sep 29 07:40:05 lordvan.com dbmail-timsieved[22749]: [0xb4ce00]
Debug:[clientbase] ci_cork(+205): [0x7f47eba06010]
Sep 29 07:40:05 lordvan.com dbmail-timsieved[22749]: [0xb4ce00]
Debug:[clientbase] ci_write(+343): [0x7f47eba06010] S >

.... this continues for quite a while (while I am not sure what/who is
connecting all the time I am sure of one thing:

dbmail-timsieved seems not to close that socket again since the number
of open sockets gets steadily increased (by 2) after every connection
event - also the fd handles mentioned here in the log from
client_error_cb are socket handle numbers.

Unfortunately I don't have the time to dig into the code more right now,
but this seems like a file-handle leak (if you can call it that)

Do you have any idea why this would happen / how to fix this?

Also my first idea how to tackle this issue with the logs getting huge
was to use syslog instead, so I went to set the config like this
file_logging_levels       = 0
syslog_logging_levels     = 31

now I don't know why but I am not getting a single line of logging from
dbmail to my syslog-ng and can'T figure out why. Just to be sure I
looked at some of the code and then wrote a little test program:

#include <stdio.h>
#include <syslog.h>

int main (int argc, char **argv)
{
  openlog("syslogtest", LOG_PID, LOG_MAIL);
  syslog(LOG_ERR, "Syslog test level ERR");
  syslog(LOG_WARNING, "Syslog test level WARNING");
  syslog(LOG_NOTICE, "Syslog test level NOTICE");
  syslog(LOG_INFO, "Syslog test level INFO");
  return 0;
}

this does log to my syslog just fine so I am at a loss why I don't get
dbmail logging to syslog. any ideas?

Regards