pid1: preserve current value of log level across re-{load,execution}

To make debugging easier, this patches allows one to change the log level and
do reload/reexec without modifying configuration permanently, which makes
debugging easier.

Indeed if one changed the log max level at runtime (via the bus or via
signals), the change was lost on the next daemon reload/reexecution.

In order to restore the original value back (set via system.conf, environment
variables or any other means), the empty string in the "LogLevel" property is
now supported as well as sending SIGRTMIN+23 signal.

diff --git a/man/elogind.xml b/man/elogind.xml
index 7cf3f7d87666028d4c9bd8cccea26cc5a979d910..bfe130e9872c1714e1446fffc23629cc54953485 100644 (file)
--- a/man/elogind.xml
+++ b/man/elogind.xml
@@ -839,15 +839,18 @@
 
       <varlistentry>
         <term><constant>SIGRTMIN+22</constant></term>
+
+        <listitem><para>Sets the service manager's log level to <literal>debug</literal>, in a fashion equivalent to
+        <varname>systemd.log_level=debug</varname> on the kernel command line.</para></listitem>
+      </varlistentry>
+
+      <varlistentry>
         <term><constant>SIGRTMIN+23</constant></term>
 
-        <listitem><para>Sets the log level to <literal>debug</literal>
-        (or <literal>info</literal> on
-        <constant>SIGRTMIN+23</constant>), as controlled via
-        <varname>systemd.log_level=debug</varname> (or
-        <varname>systemd.log_level=info</varname> on
-        <constant>SIGRTMIN+23</constant>) on the kernel command
-        line.</para></listitem>
+        <listitem><para>Restores the log level to its configured value. The configured value is derived from – in order
+        of priority – the value specified with <varname>systemd.log-level=</varname> on the kernel command line, or the
+        value specified with <option>LogLevel=</option> in the configuration file, or the built-in default of
+        <literal>info</literal>.</para></listitem>
       </varlistentry>
 
       <varlistentry>