Date: Sat, 15 Apr 2017 04:00:27 -0700 From: Maxim Sobolev <sobomax@freebsd.org> To: Peter Wemm <peter@wemm.org> Cc: "Ngie Cooper (yaneurabeya)" <yaneurabeya@gmail.com>, svn-src-all@freebsd.org, src-committers <src-committers@freebsd.org>, Hiroki Sato <hrs@freebsd.org>, Hiren Panchasara <hiren@freebsd.org>, svn-src-head@freebsd.org Subject: Re: svn commit: r316874 - head/sys/kern Message-ID: <CAH7qZfvzToECHZLCmrSBhE_3oV8sOv08OPXNfrT4hnag4X6BUQ@mail.gmail.com> In-Reply-To: <11221477.gRA6BXfcIE@overcee.wemm.org> References: <201704141723.v3EHNS3B043902@repo.freebsd.org> <2109294.KVn8xeR1jZ@overcee.wemm.org> <CDFAE7DD-8F3A-43D9-AAD5-DF9FABEC4669@gmail.com> <11221477.gRA6BXfcIE@overcee.wemm.org>
next in thread | previous in thread | raw e-mail | index | archive | help
Peter, Ngie, none of this stuff is really directly related to the
shutdown(2) change, so I'll probably let Hiroki to clean it up.
-Max
On Fri, Apr 14, 2017 at 11:58 PM, Peter Wemm <peter@wemm.org> wrote:
> On Friday, April 14, 2017 08:13:52 PM Ngie Cooper wrote:
> > > On Apr 14, 2017, at 20:12, Peter Wemm <peter@wemm.org> wrote:
> > >
> > > On Friday, April 14, 2017 07:36:55 PM Peter Wemm wrote:
> > >> On Friday, April 14, 2017 02:14:16 PM Ngie Cooper wrote:
> > >>>> On Apr 14, 2017, at 14:10, Maxim Sobolev <sobomax@sippysoft.com>
> wrote:
> > >>>>
> > >>>> Peter, Ngie,
> > >>>>
> > >>>> Looks like out of that refactoring came a logical bug that is
> present
> > >>>> in
> > >>>> the head, which causes syslod to first to shutdown the socket for
> > >>>> reading
> > >>>> and then try to select/recv on it (which is somewhat stupid). And
> that
> > >>>> issue has been masked by shutdown() on datagram socket becoming
> > >>>> effectively a NOP in 11 & head 20 months ago. It only affects head
> > >>>> though, 11-stable still has the old code which does not include that
> > >>>> half-closed socket into the select list. Attached patch is expected
> to
> > >>>> fix head, Peter, it would be nice if you can give it a try
> (restoring
> > >>>> latest changes into uipc_sockets.c) and let me know if it helps.
> > >>>>
> > >>>> Thanks!
> > >>>
> > >>> CCing hrs@ for input as he did the refactoring.
> > >>> Thanks!
> > >>> -Ngie
> > >>>
> > >>> PS LGTM with the change. Will wait for feedback from wemm@.
> > >>
> > >> This is definitely not working. I get ENOSPC and listen queue
> overflows
> > >> on /var/run/logpriv now.
> > >>
> > >> Grabbing an old 10.3 /usr/sbin/syslogd and placing it on the top of
> the
> > >> 12.x one worked fine, aside from the include statements.
> > >
> > > This can't be right:
> > > if (SecureMode || res->ai_family == AF_LOCAL) {
> > >
> > > /* Forbid communication in secure mode. */
> > > if (shutdown(s, SHUT_RD) < 0 &&
> > >
> > > errno != ENOTCONN) {
> > >
> > > logerror("shutdown");
> > > if (!Debug)
> > >
> > > die(0);
> > >
> > > }
> > > dprintf("listening on socket\n");
> > > sl_recv = NULL;
> > >
> > > }
> > >
> > > This appears to disable unix domain sockets like /var/run/log and
> > > /var/run/logpriv.
> >
> > ACK. This looks like a fun bug.
>
> > -Ngie
>
> I suspect it's meant to be "if (SecureMode && res->ai_family != AF_LOCAL)
> {"
> as a simple logic inversion error of another line earlier. However
> there's an
> awful lot of strange things in this code.
>
> 1) listen(s, 5) - on datagram sockets.
> 2) dprintf("shutdown") in code regardless of whether the shutdown is going
> to
> happen.
> 3) dprintf("listening on socket") in code that only happens when we're NOT
> going to listen.
> 4) dprintf("sending on socket") in the code path when we're going to
> listen.
> 5) shutdown on all unix domain sockets, regardless of securemode..
>
> This code block makes my head spin.
>
> --
> Peter Wemm - peter@wemm.org; peter@FreeBSD.org; peter@yahoo-inc.com;
> KI6FJV
> UTF-8: for when a ' or ... just won\342\200\231t do\342\200\246
>
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?CAH7qZfvzToECHZLCmrSBhE_3oV8sOv08OPXNfrT4hnag4X6BUQ>