On Wed, Oct 28, 2020 at 6:40 PM Joe Orton <jor...@redhat.com> wrote:
>
> On Wed, Oct 21, 2020 at 05:17:01PM +0100, Adam Hill wrote:
> > On Linux at least, you can see how much unsent data remains by querying the
> > SIOCOUTQ ioctl, so the mitigation would be to check to see that ANY data
> > was draining at all, and if so ( and there's some left ) extend the
> > lingering close time and repeat. However, this wouldn't be a cross platform
> > solution, but it would at least be the "correct" thing to do in terms of
> > network function. Not sure if there's an equivalent on other systems.
>
> Nice writeup, thank you.
+1
> So I kind of wish that
> something was missed here, but multiple people have come to exactly that
> conclusion independently.
It may be due to r1802875 where I added RST (SO_LINGER.l_linger = 0)
after lingering close timeout.
Thinking of it now, it's probably not the right thing to do. Simply
calling apr_socket_close() in abort_socket_nonblocking() would allow
the system's lingering close after httpd's.
Adam, can you still observe the same behaviour with the attached
mpm_event patch applied?
Regards;
Yann.
Index: server/mpm/event/event.c
===================================================================
--- server/mpm/event/event.c (revision 1881339)
+++ server/mpm/event/event.c (working copy)
@@ -526,21 +526,6 @@ static void abort_socket_nonblocking(apr_socket_t
{
apr_status_t rv;
apr_socket_timeout_set(csd, 0);
-#if defined(SOL_SOCKET) && defined(SO_LINGER)
- /* This socket is over now, and we don't want to block nor linger
- * anymore, so reset it. A normal close could still linger in the
- * system, while RST is fast, nonblocking, and what the peer will
- * get if it sends us further data anyway.
- */
- {
- apr_os_sock_t osd = -1;
- struct linger opt;
- opt.l_onoff = 1;
- opt.l_linger = 0; /* zero timeout is RST */
- apr_os_sock_get(&osd, csd);
- setsockopt(osd, SOL_SOCKET, SO_LINGER, (void *)&opt, sizeof opt);
- }
-#endif
rv = apr_socket_close(csd);
if (rv != APR_SUCCESS) {
ap_log_error(APLOG_MARK, APLOG_ERR, rv, ap_server_conf, APLOGNO(00468)
