On Mar 21, 2009, at 9:25 AM, Daniel Stenberg wrote:
On Fri, 20 Mar 2009, Chad Monroe wrote:
* Expire cleared
* Connection #0 to host 10.4.4.204 left intact
About ~10 seconds later the server sends another packet on this
socket, poll() fires, and my application calls
curl_multi_perform(). I'm guessing that because the transfer is
finished, curl_multi_perform() does not perform any action on this
socket as I get stuck in this loop forever. poll() continuously
fires with an event of POLLIN and curl_multi_perform() gets called.
curl_multi_fdset() still reports the descriptor as in use at this
time.
I don't get it. If the transfer is complete and the socket is no
longer used by any active easy handle, why does it still get used in
poll() ? The moment that transfer was completed, libcurl will of
course no longer use that socket nor care about it if something
arrives on it.
Looking at the libcurl code, it looks like sockets are only closed
upon error, or when calling curl_multi_cleanup().
Yes, or if the server says so or just closes it, or if you tell
libcurl to not re-use the handle for that specific transfer
(CURLOPT_FORBID_REUSE).
1.) retrieve all sockets used by a specific easy handle so I can
close them manually
2.) tell libcurl to close all sockets associated with an easy handle
Neither option exist but for the reason that they really shouldn't
be needed. You _either_ don't want the connection to be kept around
and re-use and then you tell libcurl to not re-use it, or you want
it to be re-use and then you want it kept open as much as possible
(of course limited by the limiter for max number of connections).
And recently libcurl has also got a lot better to kill connections
that died recently, even before they are attempted to get re-used so
thus it will now keep less sockets in TIME_WAIT or other "almost-
dead" states.
Or is there some other better way to solve my problem?
The primary question is simply why you poll() on sockets not used by
libcurl any longer?
--
/ daniel.haxx.se
Hi Daniel,
Thanks for the quick response. The reason I continue to poll() on
sockets "not used by libcurl any longer" is because curl_multi_fdset()
returns them in the fd_set data even after the connection has
finished. I assume this is because libcurl leaves the sockets open as
denoted by the message:
* Connection #0 to host 10.4.4.204 left intact
I'm not sure if this is the intended behavior of curl_multi_fdset() or
if it's possibly a bug. If you think it's an issue I can investigate
further if you'd like.
In any case, I checked out CURLOPT_FORBID_REUSE and it causes libcurl
to perform exactly how I want. When the connection is complete it
closes the sockets and removes them from the fd_set returned by
curl_multi_fdset() which causes my application to remove them from
poll().
--
Chad Monroe
