On Fri, Dec 6, 2013 at 1:05 PM, sven falempin <sven.falem...@gmail.com> wrote: > > > > On Fri, Dec 6, 2013 at 12:14 PM, Nick Mathewson <ni...@freehaven.net> wrote: >> >> On Thu, Dec 5, 2013 at 12:22 AM, sven falempin <sven.falem...@gmail.com> >> wrote: >> > hello: >> > >> > libevent-2.0.21-stable >> > >> > https://forums.freebsd.org/viewtopic.php?f=35&t=43654&p=242811#p242811 >> > >> > event_assign(&serv_sock_evt, evt_base, >> > sock, EV_READ | EV_PERSIST, >> > server::serv_sock_accept_pattern, this); >> > event_add(&serv_sock_evt, NULL); >> > >> > then i do new in server::serv_sock_accept_pattern and path the arguments >> > to >> > accept. >> > >> > But apparently socket has nothing to accept. >> > >> > It is not easy to produce.... >> > >> > help/insight welcome. >> >> I'm not seeing an obvious problem with that code, assuming that >> server::serv_sock_accept_pattern has the right signature and is >> declared as 'cdecl' if that's necessary. If you're doing anything >> unusual with threads, that could account for a socket appearing >> readable but having nothing to accept when you look at it .. but you >> probably would have thought of that. >> >> A few possibly-not-too-helpful thoughts I have for debugging: >> >> 1) use strace or truss or whatever the best FreeBSD syscall logging >> tool is to see what exactly is going on with the fd in question. Are >> there weird syscalls happening to it? Is something calling accept() >> twice somehow? > > > it is ktrace :-) it has a binary format you read with kdump. If i reproduce > i gonna check this. > > >> >> 2) If you're multithreaded, make sure that you've enabled all the >> locking stuff that you need in libevent. > > > > done :-) was a bit messy but it looks ok now.
Great. Remember, you need to enable threading before you create any event_base, and you need to explicitly make any bufferevent or similar thing that can be used or affected by multiple threads locked. http://www.wangafu.net/~nickm/libevent-book/Ref1_libsetup.html has more details than you necessarily want :) >> 3) If you haven't done so already, use helgrind and valgrind to look >> for whether some kind of fishy corruption might be going on. > > > > I always valgrind (helgrind ?) . Part of the valgrind suite. Like valgrind, but for muliththreading errors: http://valgrind.org/docs/manual/hg-manual.html >> 4) Try to come up with a minimal program and/or testing environment >> to reproduce the failing case. > > >> >> 5) If it's not too hard, try dropping in evconnlistener in place of >> your current listen/accept logic and see if the problem persists. If >> not, it's likely an issue in your code somewhere. > > ? > Libevent provides a wrapper for accepting TCP connections so that you don't need to do listen/accept yourself: http://www.wangafu.net/~nickm/libevent-book/Ref8_listener.html best wishes, -- Nick *********************************************************************** To unsubscribe, send an e-mail to majord...@freehaven.net with unsubscribe libevent-users in the body.
