Perhaps this is involved with systemd and IPC namespaces? On Tue, Jul 15, 2014 at 3:32 PM, Brian Wood <woodbrian77@gmail.com> wrote:
I've been having a problem related to epoll_ctl() lately. I have a 3-tier system:
1. back tier (tcp server) 2. middle tier (udp server) 3. front tier
The problem is happening in the back tier. If I kill the middle tier with a control-C and then restart it (before making any requests via the front tier), the socket descriptor (associated with the middle tier) in the back tier is 7. But If I first make some requests via the front tier, then kill the middle tier and restart it, the socket descriptor is 1.
When the socket descriptor is 1, I get an EBADF on an epoll_ctl with an op of EPOLL_CTL_MOD. It's not on the first call to epoll_ctl that it fails, but the third call. My debugging shows that the epfd and fd are the same for all three of these calls.
I've tried many things to get the back tier to not give me the socket descriptor of 1. I've tried calling daemon(), freopen'ing stdin, stdout, and stderr, and a few other things. I've tried doing these things only in the parent, only in the child and in both. Nothing has worked. Any ideas? Thanks.
-- Brian Ebenezer Enterprises http://webEbenezer.net