logind: allow wall messages to be controlled via config file

Right now, the sending of wall messages on reboot/shutdown/etc can be
controlled via DBus properties. This patch adds support for changing the
default via the logind.conf file as well.

Note that the DBus setting is lost if logind is restarted or reloaded,
but it was already the case before this patch that the setting is lost
upon restart.

man/logind.conf.xml

@@ -409,6 +409,21 @@
 
         <xi:include href="version-info.xml" xpointer="v257"/></listitem>
       </varlistentry>
+
+      <varlistentry>
+        <term><varname>EnableWallMessages=</varname></term>
+
+        <listitem>
+          <para>
+            Controls whether
+            <citerefentry><refentrytitle>wall</refentrytitle><manvolnum>1</manvolnum></citerefentry>
+            messages should be sent to the terminals of all currently logged in users upon shutdown or
+            reboot. Defaults to <literal>yes</literal>, and can be changed at runtime via the DBus
+            <literal>EnableWallMessages</literal> and <literal>WallMessagePrefix</literal> properties.
+          </para>
+
+        <xi:include href="version-info.xml" xpointer="v258"/></listitem>
+      </varlistentry>
     </variablelist>
   </refsect1>
 

src/login/logind-core.c

@@ -39,6 +39,7 @@ void manager_reset_config(Manager *m) {
         m->remove_ipc = true;
         m->inhibit_delay_max = 5 * USEC_PER_SEC;
         m->user_stop_delay = 10 * USEC_PER_SEC;
+        m->enable_wall_messages = true;
 
         m->handle_action_sleep_mask = HANDLE_ACTION_SLEEP_MASK_DEFAULT;
 

src/login/logind-gperf.gperf

@@ -54,3 +54,4 @@ Login.SessionsMax,                  config_parse_uint64,                0, offse
 Login.DesignatedMaintenanceTime,    config_parse_calendar,              0, offsetof(Manager, maintenance_time)
 Login.UserTasksMax,                 config_parse_compat_user_tasks_max, 0, 0
 Login.StopIdleSessionSec,           config_parse_sec_fix_0,             0, offsetof(Manager, stop_idle_session_usec)
+Login.EnableWallMessages,           config_parse_bool,                  0, offsetof(Manager, enable_wall_messages)

src/login/logind.c

@@ -64,7 +64,6 @@ static int manager_new(Manager **ret) {
         *m = (Manager) {
                 .console_active_fd = -EBADF,
                 .reserve_vt_fd = -EBADF,
-                .enable_wall_messages = true,
                 .idle_action_not_before_usec = now(CLOCK_MONOTONIC),
                 .scheduled_shutdown_action = _HANDLE_ACTION_INVALID,
 

src/login/logind.conf.in

@@ -52,3 +52,4 @@
 #SessionsMax=8192
 #StopIdleSessionSec=infinity
 #DesignatedMaintenanceTime=
+#EnableWallMessages=yes