1

I'm trying to write (the beginning) of a daemon on Ubuntu 15.04 and for some reason rsyslog is refusing to output my logged statements - I've tried multiple localities (LOG_LOCAL1, LOG_LOCAL0, LOG_SYSLOG, LOG_DAEMON), restarted the rsyslog service, and have tested the code on an Arch Linux VM (it works fine).

Application Code:

#include <syslog.h>
#include <unistd.h>
#include <cstdlib>

int main(int argc, char* argv[])
{
  setlogmask(LOG_UPTO(LOG_CRIT));
  openlog("floded", LOG_CONS | LOG_PID | LOG_NDELAY, LOG_SYSLOG);
  syslog(LOG_INFO, "floded entered");   
  closelog();
  return(0);
}

/etc/rsyslog.d/50-default.conf:

#  Default rules for rsyslog.
#
#                       For more information see rsyslog.conf(5) and /etc/rsyslog.conf

#
# First some standard log files.  Log by facility.
#
auth,authpriv.*                 /var/log/auth.log
*.*;auth,authpriv.none          -/var/log/syslog
#cron.*                         /var/log/cron.log
daemon.*                        -/var/log/daemon.log
kern.*                          -/var/log/kern.log
#lpr.*                          -/var/log/lpr.log
mail.*                          -/var/log/mail.log
#user.*                         -/var/log/user.log

#
# Logging for the mail system.  Split it up so that
# it is easy to write scripts to parse these files.
#
#mail.info                      -/var/log/mail.info
#mail.warn                      -/var/log/mail.warn
mail.err                        /var/log/mail.err

#
# Logging for INN news system.
#
news.crit                       /var/log/news/news.crit
news.err                        /var/log/news/news.err
news.notice                     -/var/log/news/news.notice

#
# Some "catch-all" log files.
#
#*.=debug;\
#       auth,authpriv.none;\
#       news.none;mail.none     -/var/log/debug
#*.=info;*.=notice;*.=warn;\
#       auth,authpriv.none;\
#       cron,daemon.none;\
#       mail,news.none          -/var/log/messages

#
# Emergencies are sent to everybody logged in.
#
*.emerg                                :omusrmsg:*

#
# I like to have messages displayed on the console, but only on a virtual
# console I usually leave idle.
#
#daemon,mail.*;\
#       news.=crit;news.=err;news.=notice;\
#       *.=debug;*.=info;\
#       *.=notice;*.=warn       /dev/tty8

# The named pipe /dev/xconsole is for the `xconsole' utility.  To use it,
# you must invoke `xconsole' with the `-file' option:
#
#    $ xconsole -file /dev/xconsole [...]
#
# NOTE: adjust the list below, or you'll go crazy if you have a reasonably
#      busy site..
#
daemon.*;mail.*;\
        news.err;\
        *.=debug;*.=info;\
        *.=notice;*.=warn       |/dev/xconsole

What am I missing?

1 Answer 1

0

The line setlogmask(LOG_UPTO(LOG_CRIT)) discards your log message

syslog(LOG_INFO, "floded entered");

The priority of LOG_INFO is lower than the priority of LOG_CRIT. Therefore

#include <syslog.h>
#include <unistd.h>
#include <cstdlib>

int main(int argc, char* argv[])
{
  // setlogmask(LOG_UPTO(LOG_CRIT));
  openlog("floded", LOG_CONS | LOG_PID | LOG_NDELAY, LOG_SYSLOG);
  syslog(LOG_INFO, "floded entered");   
  closelog();
  return(0);
}

or

#include <syslog.h>
#include <unistd.h>
#include <cstdlib>

int main(int argc, char* argv[])
{
  setlogmask(LOG_UPTO(LOG_INFO));
  openlog("floded", LOG_CONS | LOG_PID | LOG_NDELAY, LOG_SYSLOG);
  syslog(LOG_INFO, "floded entered");   
  closelog();
  return(0);
}
1
  • LOG_UPTO has a very deceitful name - thanks for clearing this up!
    – iikorni
    Oct 14, 2015 at 18:07

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