Since sd_journal_send uses fd = journal_fd(); which has
fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0); this socket is opened without a non-blocking call. This might cause the unix socket daemon to block this . The other approach could be passing a nonblocking flag to k = sendmsg(fd, &mh, MSG_NOSIGNAL); *MSG_DONTWAIT* flag . ARE ANY OF THESE APPROACHES TRIED OR is there a plan to support this complete non blocking sd_journal_print call ? regards On Thu, Jul 18, 2019 at 2:52 AM Mantas Mikulėnas <graw...@gmail.com> wrote: > On Thu, Jul 18, 2019 at 12:44 PM Ulrich Windl < > ulrich.wi...@rz.uni-regensburg.de> wrote: > >> >>> Mantas Mikulenas <graw...@gmail.com> schrieb am 18.07.2019 um 10:06 >> in >> Nachricht >> <capwny8xs1jw9iu_a-tagnw-v0nqemacwdrpftpdekw_nfan...@mail.gmail.com>: >> > On Thu, Jul 18, 2019 at 10:32 AM Ulrich Windl < >> > ulrich.wi...@rz.uni-regensburg.de> wrote: >> > >> >> >>> Vaibhav Dahiya <vdah...@ncsu.edu> schrieb am 18.07.2019 um 02:53 >> in >> >> Nachricht >> >> <5d2fc2f0.1c69fb81.214d0.1...@mx.google.com>: >> >> > Hello, >> >> > >> >> > I am using sd_journal_send api() api call to log messages on syslog >> >> server. >> >> > I see that this uses >> >> > sendmsg(fd, &mh, MSG_NOSIGNAL) call. >> >> >> >> Aren't syslog messages UDP anyway? When would an UDP send block? >> >> >> > >> > No, program APIs use Unix sockets (/dev/log, >> /run/systemd/journal/socket). >> > You only get UDP when your local syslog daemon is configured to forward >> > elsewhere. >> > >> > That said, both are datagram sockets, I'm not sure whether sending to >> Unix >> > dgram sockets can block or not? >> >> ??? Datagram _is_ UDP >> > > UDP is datagram, but datagram is not always UDP. > > "UDP" specifically means the datagram transport protocol that runs over > IPv4/IPv6, nothing else. Unix sockets (AF_UNIX) have a datagram mode but > they do not use UDP (or IP). Netlink is datagram-based but it isn't > UDP-based. &c. > > -- > Mantas Mikulėnas > _______________________________________________ > systemd-devel mailing list > systemd-devel@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/systemd-devel -- Best Regards, Vaibhav Dahiya Master's. Candidate in CSC (Computer Science) North Carolina State University Ph: (919) 888-8429
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