enhanced configuration file error reporting and verification

- enhanced config file checking - no active actions are detected
- added -N rsyslogd command line option for a config validation run
  (which does not execute actual syslogd code and does not interfere
  with a running instance)
- somewhat improved emergency configuration. It is now also selected
  if the config contains no active actions
- rsyslogd error messages are now reported to stderr by default. can be
  turned off by the new "$ErrorMessagesToStderr off" directive
Thanks to HKS for suggesting these new features.

1 files changed, 16 insertions, 0 deletions

diff --git a/tools/rsyslogd.8 b/tools/rsyslogd.8
index 91f2016e..947102de 100644
--- a/tools/rsyslogd.8
+++ b/tools/rsyslogd.8
@@ -21,6 +21,9 @@ rsyslogd \- reliable and extended syslogd
 .I hostlist
 ]
 .RB [ " \-n " ]
+.RB [ " \-N "
+.I level
+]
 .br
 .RB [ " \-q " ]
 .RB [ " \-Q " ]
@@ -166,6 +169,19 @@ Avoid auto-backgrounding.  This is needed especially if the
 is started and controlled by
 .BR init (8).
 .TP
+.B "\-N " "level"
+Do a coNfig check. Do NOT run in regular mode, just check configuration
+file correctness.
+This option is meant to verify a config file. To do so, run rsyslogd
+interactively in foreground, specifying -f <config-file> and -N level.
+The level argument modifies behaviour. Currently, 0 is the same as
+not specifying the -N option at all (so this makes limited sense) and
+1 actually activates the code. Later, higher levels will mean more
+verbosity (this is a forward-compatibility option).
+.B rsyslogd
+is started and controlled by
+.BR init (8).
+.TP
 .BI "\-q " "add hostname if DNS fails during ACL processing"
 During ACL processing, hostnames are resolved to IP addreses for
 performance reasons. If DNS fails during that process, the hostname