manager: add log control via RT signals

TODO

@@ -36,7 +36,7 @@ Features:
 
 * logind: non-local X11 server handling
 
-* logind: use sysfs path in device hash table instead of syname, as soon as fb driver is fixed
+* logind: use sysfs path in device hash table instead of sysname, as soon as fb driver is fixed
 
 * possibly apply systemd-sysctl per network device subtrees on hotplug
 
@@ -59,7 +59,9 @@ Features:
 
 * readahead: check whether a btrfs volume includes ssd by checking mount flag "ssd"
 
-* support sd_notify() style notificatio when reload is finished (RELOADED=1)
+* support sd_notify() style notification when reload is finished (RELOADED=1)
+
+* support sf_notify() style notification when shutting down, to make auto-exit bus services work
 
 * verify that the AF_UNIX sockets of a service in the fs still exist
   when we start a service in order to avoid confusion when a user
@@ -68,8 +70,6 @@ Features:
 * Make it possible to set the keymap independently from the font on
   the kernel cmdline. Right now setting one resets also the other.
 
-* add dbus call to convert snapshot into target
-
 * move nss-myhostname into systemd
 
 * figure out a standard place to configure timezone name, inform myllynen@redhat.com
@@ -84,14 +84,8 @@ Features:
 
 * allow list of paths in config_parse_condition_path()
 
-* introduce dbus calls for enabling/disabling a service
-
-* support notifications for services being enabled/disabled
-
 * show enablement status in systemctl status
 
-* consider services with any kind of link in /etc/systemd/system enabled
-
 * teach systemctl to enable unit files in arbitrary directories
 
 * In systemctl make sure both is-enabled and is-active print a string, or neither.
@@ -101,6 +95,8 @@ Features:
     systemctl unmask <unit>
   Also support --temp to make this temporary by placing mask links in /run.
 
+* perhaps add "systemctl reenable" as combination of "systemctl disable" and "systemctl enable"
+
 * add support for /bin/mount -s
 
 * GC unreferenced jobs (such as .device jobs)
@@ -120,8 +116,8 @@ Features:
 * write blog stories about:
   - enabling dbus services
   - status update
-  - /etc/sysconfig and /etc/default
   - how to make changes to sysctl and sysfs attributes
+  - remote access
 
 * allow port=0 in .socket units
 
@@ -189,12 +185,8 @@ Features:
 
 * make sure timeouts are applied to Type=oneshot services.
 
-* detect LXC environment
-
 * investigate whether the gnome pty helper should be moved into systemd, to provide cgroup support.
 
-* perhaps add "systemctl reenable" as combination of "systemctl disable" and "systemctl enable"
-
 * need a way to apply mount options of api vfs from systemd unit files
   (or some other modern source?) instead of fstab?
 
@@ -218,16 +210,6 @@ Features:
 * systemd --user
   - get PR_SET_ANCHOR merged: http://lkml.org/lkml/2010/2/2/165
 
-* add VT tracking:
-  - provide CK functionality
-  - start getty only when actual vt switch happens (same model as
-    socket on-demand activation). allocate the next free tty and
-    start a getty there. this way, pressing alt-f[1-12] will switch
-    through running X and getty sessions, and any unallocated
-    activated tty will start a new getty. the hardcoding of
-    getty[1-6] will entirely go away.
-  - http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=fbc92a3455577ab17615cbcb91826399061bd789
-
 * implicitly import "defaults" settings file into all types
 
 * port over to LISTEN_FDS/LISTEN_PID:

man/systemd.xml

@@ -800,6 +800,44 @@
                                 on the kernel command
                                 line.</para></listitem>
                         </varlistentry>
+
+                        <varlistentry>
+                                <term>SIGRTMIN+22</term>
+                                <term>SIGRTMIN+23</term>
+
+                                <listitem><para>Sets the log level to
+                                <literal>debug</literal>
+                                (resp. <literal>info</literal> on
+                                <literal>SIGRTMIN+32</literal>), as
+                                controlled via
+                                <varname>systemd.log_level=debug</varname>
+                                (resp. <varname>systemd.log_level=info</varname>
+                                on <literal>SIGRTMIN+23</literal>) on
+                                the kernel command
+                                line.</para></listitem>
+                        </varlistentry>
+
+                        <varlistentry>
+                                <term>SIGRTMIN+27</term>
+                                <term>SIGRTMIN+28</term>
+                                <term>SIGRTMIN+29</term>
+
+                                <listitem><para>Sets the log level to
+                                <literal>console</literal>
+                                (resp. <literal>kmsg</literal> on
+                                <literal>SIGRTMIN+28</literal>;
+                                resp.<literal>syslog-or-kmsg</literal>
+                                on <literal>SIGRTMIN+29</literal>), as
+                                controlled via
+                                <varname>systemd.log_target=console</varname>
+                                (resp. <varname>systemd.log_target=kmsg</varname>
+                                on <literal>SIGRTMIN+28</literal>;
+                                resp
+                                <varname>systemd.log_target=syslog-or-kmsg</varname>
+                                on <literal>SIGRTMIN+29</literal>) on
+                                the kernel command
+                                line.</para></listitem>
+                        </varlistentry>
                 </variablelist>
         </refsect1>
 

src/manager.c

@@ -186,6 +186,11 @@ static int manager_setup_signals(Manager *m) {
                         SIGRTMIN+16, /* systemd: Immediate kexec */
                         SIGRTMIN+20, /* systemd: enable status messages */
                         SIGRTMIN+21, /* systemd: disable status messages */
+                        SIGRTMIN+22, /* systemd: set log level to LOG_DEBUG */
+                        SIGRTMIN+23, /* systemd: set log level to LOG_INFO */
+                        SIGRTMIN+27, /* systemd: set log target to console */
+                        SIGRTMIN+28, /* systemd: set log target to kmsg */
+                        SIGRTMIN+29, /* systemd: set log target to syslog-or-kmsg */
                         -1);
         assert_se(sigprocmask(SIG_SETMASK, &mask, NULL) == 0);
 
@@ -2200,6 +2205,7 @@ static int manager_process_signal_fd(Manager *m) {
                         break;
 
                 default: {
+
                         /* Starting SIGRTMIN+0 */
                         static const char * const target_table[] = {
                                 [0] = SPECIAL_DEFAULT_TARGET,
@@ -2244,6 +2250,31 @@ static int manager_process_signal_fd(Manager *m) {
                                 m->show_status = false;
                                 break;
 
+                        case 22:
+                                log_set_max_level(LOG_DEBUG);
+                                log_notice("Setting log level to debug.");
+                                break;
+
+                        case 23:
+                                log_set_max_level(LOG_INFO);
+                                log_notice("Setting log level to info.");
+                                break;
+
+                        case 27:
+                                log_set_target(LOG_TARGET_CONSOLE);
+                                log_notice("Setting log target to console.");
+                                break;
+
+                        case 28:
+                                log_set_target(LOG_TARGET_KMSG);
+                                log_notice("Setting log target to kmsg.");
+                                break;
+
+                        case 29:
+                                log_set_target(LOG_TARGET_SYSLOG_OR_KMSG);
+                                log_notice("Setting log target to syslog-or-kmsg.");
+                                break;
+
                         default:
                                 log_warning("Got unhandled signal <%s>.", strna(signal_to_string(sfsi.ssi_signo)));
                         }