Bug#832637: More info

On Sun, Aug 21, 2016 at 4:27 PM, Brian Potkin <claremont102@gmail.com> wrote:

Are you positive cups.service is still running while cups-browsed is
stopping? 'systemctl status cups' in another terminal would tell you.

Yes

If I use the sequence

systemctl start cups cups-browsed.service
systemctl stop cups-browsed.service

it stops cups-browsed immediately here.

I just did:

# systemctl start cups cups-browsed.service
# systemctl status cups cups-browsed.service
cups.service - CUPS Scheduler
   Loaded: loaded (/lib/systemd/system/cups.service; enabled; vendor preset: ena
   Active: active (running) since Sun 2016-08-21 09:14:34 CEST; 8h ago
   ...
cups-browsed.service - Make remote CUPS printers available locally
   Loaded: loaded (/lib/systemd/system/cups-browsed.service; enabled; vendor pre
   Active: active (running) since Sun 2016-08-21 17:16:33 CEST; 9s ago
   ...
# systemctl stop cups-browsed.service
(waits 90 sec)

If I strace the cups-browsed process (all threads) during tese 90 seconds I see it repeats the following until it gets killed:

19552 connect(10, {sa_family=AF_INET6, sin6_port=htons(631), inet_pton(AF_INET6, "::1", &sin6_addr), sin6_flowinfo=0, sin6_scope_id=0}, 28) = -1 EINPROGRESS (Operation now in progress)
19552 fcntl(10, F_SETFL, O_RDWR)        = 0
19552 poll([{fd=10, events=POLLIN|POLLOUT}], 1, 100) = 1 ([{fd=10, revents=POLLIN|POLLOUT|POLLERR|POLLHUP}])
19552 sendto(10, "POST / HTTP/1.1\r\nContent-Length:"..., 169, 0, NULL, 0) = -1 ECONNREFUSED (Connection refused)
19552 sendto(10, "POST / HTTP/1.1\r\nContent-Length:"..., 169, 0, NULL, 0) = -1 EPIPE (Broken pipe)
19552 --- SIGPIPE {si_signo=SIGPIPE, si_code=SI_USER, si_pid=19552, si_uid=0} ---
19552 sendto(10, "POST / HTTP/1.1\r\nContent-Length:"..., 169, 0, NULL, 0) = -1 EPIPE (Broken pipe)
19552 --- SIGPIPE {si_signo=SIGPIPE, si_code=SI_USER, si_pid=19552, si_uid=0} ---
19552 close(10)                         = 0
19552 socket(AF_INET6, SOCK_STREAM, IPPROTO_IP) = 10
19552 setsockopt(10, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0
19552 setsockopt(10, SOL_SOCKET, SO_REUSEPORT, [1], 4) = 0
19552 setsockopt(10, SOL_TCP, TCP_NODELAY, [1], 4) = 0
19552 fcntl(10, F_SETFD, FD_CLOEXEC)    = 0
19552 fcntl(10, F_GETFL)                = 0x2 (flags O_RDWR)
19552 fcntl(10, F_SETFL, O_RDWR|O_NONBLOCK) = 0
19552 connect(10, {sa_family=AF_INET6, sin6_port=htons(631), inet_pton(AF_INET6, "::1", &sin6_addr), sin6_flowinfo=0, sin6_scope_id=0}, 28) = -1 EINPROGRESS (Operation now in progress)
19552 fcntl(10, F_SETFL, O_RDWR)        = 0
19552 poll([{fd=10, events=POLLIN|POLLOUT}], 1, 100) = 1 ([{fd=10, revents=POLLIN|POLLOUT|POLLERR|POLLHUP}])
19552 sendto(10, "POST / HTTP/1.1\r\nContent-Length:"..., 169, 0, NULL, 0) = -1 ECONNREFUSED (Connection refused)
...

Cheers, Roderich