Merge pull request #6944 from poettering/suspend-fix

systemctl reboot/suspend tweaks

NEWS

@@ -190,6 +190,20 @@ CHANGES WITH 235:
           used to control how the kernel keyring is set up for executed
           processes.
 
+        * "systemctl poweroff", "systemctl reboot", "systemctl halt",
+          "systemctl kexec" and "systemctl exit" are now always asynchronous in
+          behaviour (that is: these commands return immediately after the
+          operation was enqueued instead of waiting until the operation was
+          completed). Previously, "systemctl poweroff" and "systemctl reboot"
+          were asynchronous on systems using systemd-logind (i.e. almost
+          always, and like they were on sysvinit), and the other three commands
+          were unconditionally synchronous. With this release this is cleaned
+          up, and callers will see the same asynchronous behaviour on all
+          systems for all five operations.
+
+        * systemd-logind gained new Halt() and CanHalt() bus calls for halting
+          the system.
+
         * .timer units now accept calendar specifications in other timezones
           than UTC or the local timezone.
 
@@ -222,7 +236,7 @@ CHANGES WITH 235:
         userwithuid, Vito Caputo, vliaskov, WaLyong Cho, William Douglas, Xiang
         Fan, Yu Watanabe, Zbigniew Jędrzejewski-Szmek
 
-        — Berlin, 2017-09-XX
+        — Berlin, 2017-10-XX
 
 CHANGES WITH 234:
 

man/systemctl.xml

@@ -407,8 +407,7 @@
         <term><option>--no-wall</option></term>
 
         <listitem>
-          <para>Do not send wall message before halt, power-off,
+          <para>Do not send wall message before halt, power-off and reboot.</para>
-          reboot.</para>
         </listitem>
       </varlistentry>
 
@@ -525,7 +524,7 @@
           <option>--force</option> twice with any of these operations might result in data loss. Note that when
           <option>--force</option> is specified twice the selected operation is executed by
           <command>systemctl</command> itself, and the system manager is not contacted. This means the command should
-          succeed even when the system manager hangs or crashed.</para>
+          succeed even when the system manager has crashed.</para>
         </listitem>
       </varlistentry>
 
@@ -533,11 +532,9 @@
         <term><option>--message=</option></term>
 
         <listitem>
-          <para>When used with <command>halt</command>,
+          <para>When used with <command>halt</command>, <command>poweroff</command> or <command>reboot</command>, set a
-          <command>poweroff</command>, <command>reboot</command> or
+          short message explaining the reason for the operation. The message will be logged together with the default
-          <command>kexec</command>, set a short message explaining the reason
+          shutdown message.</para>
-          for the operation. The message will be logged together with the
-          default shutdown message.</para>
         </listitem>
       </varlistentry>
 
@@ -1690,8 +1687,8 @@ Jan 12 10:46:45 example.com bluetoothd[8900]: gatt-time-server: Input/output err
           <term><command>default</command></term>
 
           <listitem>
-            <para>Enter default mode. This is mostly equivalent to
+            <para>Enter default mode. This is equivalent to <command>systemctl isolate default.target</command>. This
-            <command>isolate default.target</command>.</para>
+            operation is blocking by default, use <option>--no-block</option> to request asynchronous behavior.</para>
           </listitem>
         </varlistentry>
 
@@ -1699,72 +1696,77 @@ Jan 12 10:46:45 example.com bluetoothd[8900]: gatt-time-server: Input/output err
           <term><command>rescue</command></term>
 
           <listitem>
-            <para>Enter rescue mode. This is mostly equivalent to
+            <para>Enter rescue mode. This is equivalent to <command>systemctl isolate rescue.target</command>. This
-            <command>isolate rescue.target</command>, but also prints a
+            operation is blocking by default, use <option>--no-block</option> to request asynchronous behavior.</para>
-            wall message to all users.</para>
           </listitem>
         </varlistentry>
         <varlistentry>
           <term><command>emergency</command></term>
 
           <listitem>
-            <para>Enter emergency mode. This is mostly equivalent to
+            <para>Enter emergency mode. This is equivalent to <command>systemctl isolate
-            <command>isolate emergency.target</command>, but also prints
+            emergency.target</command>. This operation is blocking by default, use <option>--no-block</option> to
-            a wall message to all users.</para>
+            request asynchronous behavior.</para>
           </listitem>
         </varlistentry>
         <varlistentry>
           <term><command>halt</command></term>
 
           <listitem>
-            <para>Shut down and halt the system. This is mostly equivalent to <command>start halt.target
+            <para>Shut down and halt the system. This is mostly equivalent to <command>systemctl start halt.target
-            --job-mode=replace-irreversibly</command>, but also prints a wall message to all users.  If combined with
+            --job-mode=replace-irreversibly --no-block</command>, but also prints a wall message to all users. This command is
-            <option>--force</option>, shutdown of all running services is skipped, however all processes are killed and
+            asynchronous; it will return after the halt operation is enqueued, without waiting for it to complete. Note
-            all file systems are unmounted or mounted read-only, immediately followed by the system halt.  If
+            that this operation will simply halt the OS kernel after shutting down, leaving the hardware powered
-            <option>--force</option> is specified twice, the operation is immediately executed without terminating any
+            on. Use <command>systemctl poweroff</command> for powering off the system (see below).</para>
-            processes or unmounting any file systems. This may result in data loss. Note that when
+
-            <option>--force</option> is specified twice the halt operation is executed by
+            <para>If combined with <option>--force</option>, shutdown of all running services is skipped, however all
-            <command>systemctl</command> itself, and the system manager is not contacted. This means the command should
+            processes are killed and all file systems are unmounted or mounted read-only, immediately followed by the
-            succeed even when the system manager hangs or crashed.</para>
+            system halt.  If <option>--force</option> is specified twice, the operation is immediately executed without
+            terminating any processes or unmounting any file systems. This may result in data loss. Note that when
+            <option>--force</option> is specified twice the halt operation is executed by <command>systemctl</command>
+            itself, and the system manager is not contacted. This means the command should succeed even when the system
+            manager has crashed.</para>
           </listitem>
         </varlistentry>
         <varlistentry>
           <term><command>poweroff</command></term>
 
           <listitem>
-            <para>Shut down and power-off the system. This is mostly equivalent to <command>start poweroff.target
+            <para>Shut down and power-off the system. This is mostly equivalent to <command>systemctl start
-            --job-mode=replace-irreversibly</command>, but also prints a wall message to all users. If combined with
+            poweroff.target --job-mode=replace-irreversibly --no-block</command>, but also prints a wall message to all
-            <option>--force</option>, shutdown of all running services is skipped, however all processes are killed and
+            users. This command is asynchronous; it will return after the power-off operation is enqueued, without
-            all file systems are unmounted or mounted read-only, immediately followed by the powering off. If
+            waiting for it to complete.</para>
-            <option>--force</option> is specified twice, the operation is immediately executed without terminating any
+
-            processes or unmounting any file systems. This may result in data loss. Note that when
+            <para>If combined with <option>--force</option>, shutdown of all running services is skipped, however all
+            processes are killed and all file systems are unmounted or mounted read-only, immediately followed by the
+            powering off. If <option>--force</option> is specified twice, the operation is immediately executed without
+            terminating any processes or unmounting any file systems. This may result in data loss. Note that when
             <option>--force</option> is specified twice the power-off operation is executed by
             <command>systemctl</command> itself, and the system manager is not contacted. This means the command should
-            succeed even when the system manager hangs or crashed.</para>
+            succeed even when the system manager has crashed.</para>
           </listitem>
         </varlistentry>
         <varlistentry>
           <term><command>reboot <optional><replaceable>arg</replaceable></optional></command></term>
 
           <listitem>
-            <para>Shut down and reboot the system. This is mostly equivalent to <command>start reboot.target
+            <para>Shut down and reboot the system. This is mostly equivalent to <command>systemctl start reboot.target
-            --job-mode=replace-irreversibly</command>, but also prints a wall message to all users. If combined with
+            --job-mode=replace-irreversibly --no-block</command>, but also prints a wall message to all users. This
-            <option>--force</option>, shutdown of all running services is skipped, however all processes are killed and
+            command is asynchronous; it will return after the reboot operation is enqueued, without waiting for it to
-            all file systems are unmounted or mounted read-only, immediately followed by the reboot. If
+            complete.</para>
-            <option>--force</option> is specified twice, the operation is immediately executed without terminating any
+
-            processes or unmounting any file systems. This may result in data loss. Note that when
+            <para>If combined with <option>--force</option>, shutdown of all running services is skipped, however all
+            processes are killed and all file systems are unmounted or mounted read-only, immediately followed by the
+            reboot. If <option>--force</option> is specified twice, the operation is immediately executed without
+            terminating any processes or unmounting any file systems. This may result in data loss. Note that when
             <option>--force</option> is specified twice the reboot operation is executed by
             <command>systemctl</command> itself, and the system manager is not contacted. This means the command should
-            succeed even when the system manager hangs or crashed.</para>
+            succeed even when the system manager has crashed.</para>
 
-            <para>If the optional argument
+            <para>If the optional argument <replaceable>arg</replaceable> is given, it will be passed as the optional
-            <replaceable>arg</replaceable> is given, it will be passed
+            argument to the <citerefentry><refentrytitle>reboot</refentrytitle><manvolnum>2</manvolnum></citerefentry>
-            as the optional argument to the
+            system call. The value is architecture and firmware specific. As an example, <literal>recovery</literal>
-            <citerefentry><refentrytitle>reboot</refentrytitle><manvolnum>2</manvolnum></citerefentry>
+            might be used to trigger system recovery, and <literal>fota</literal> might be used to trigger a
-            system call. The value is architecture and firmware
-            specific. As an example, <literal>recovery</literal> might
-            be used to trigger system recovery, and
-            <literal>fota</literal> might be used to trigger a
             <quote>firmware over the air</quote> update.</para>
           </listitem>
         </varlistentry>
@@ -1773,13 +1775,14 @@ Jan 12 10:46:45 example.com bluetoothd[8900]: gatt-time-server: Input/output err
           <term><command>kexec</command></term>
 
           <listitem>
-            <para>Shut down and reboot the system via kexec. This is
+            <para>Shut down and reboot the system via <command>kexec</command>. This is equivalent to
-            mostly equivalent to <command>start kexec.target --job-mode=replace-irreversibly</command>,
+            <command>systemctl start kexec.target --job-mode=replace-irreversibly --no-block</command>. This command is
-            but also prints a wall message to all users. If combined
+            asynchronous; it will return after the reboot operation is enqueued, without waiting for it to
-            with <option>--force</option>, shutdown of all running
+            complete.</para>
-            services is skipped, however all processes are killed and
+
-            all file systems are unmounted or mounted read-only,
+            <para>If combined with <option>--force</option>, shutdown of all running services is skipped, however all
-            immediately followed by the reboot.</para>
+            processes are killed and all file systems are unmounted or mounted read-only, immediately followed by the
+            reboot.</para>
           </listitem>
         </varlistentry>
 
@@ -1787,14 +1790,13 @@ Jan 12 10:46:45 example.com bluetoothd[8900]: gatt-time-server: Input/output err
           <term><command>exit <optional><replaceable>EXIT_CODE</replaceable></optional></command></term>
 
           <listitem>
-            <para>Ask the systemd manager to quit. This is only
+            <para>Ask the service manager to quit. This is only supported for user service managers (i.e. in
-            supported for user service managers (i.e. in conjunction
+            conjunction with the <option>--user</option> option) or in containers and is equivalent to
-            with the <option>--user</option> option) or in containers
+            <command>poweroff</command> otherwise. This command is asynchronous; it will return after the exit
-            and is equivalent to <command>poweroff</command> otherwise.</para>
+            operation is enqueued, without waiting for it to complete.</para>
 
-            <para>The systemd manager can exit with a non-zero exit
+            <para>The service manager will exit with the the specified exit code, if
-            code if the optional argument
+            <replaceable>EXIT_CODE</replaceable> is passed.</para>
-            <replaceable>EXIT_CODE</replaceable> is given.</para>
           </listitem>
         </varlistentry>
 
@@ -1818,9 +1820,9 @@ Jan 12 10:46:45 example.com bluetoothd[8900]: gatt-time-server: Input/output err
           <term><command>suspend</command></term>
 
           <listitem>
-            <para>Suspend the system. This will trigger activation of
+            <para>Suspend the system. This will trigger activation of the special target unit
-            the special <filename>suspend.target</filename> target.
+            <filename>suspend.target</filename>. This command is asynchronous, and will return after the suspend
-            </para>
+            operation is successfully enqueued. It will not wait for the suspend/resume cycle to complete.</para>
           </listitem>
         </varlistentry>
 
@@ -1828,9 +1830,9 @@ Jan 12 10:46:45 example.com bluetoothd[8900]: gatt-time-server: Input/output err
           <term><command>hibernate</command></term>
 
           <listitem>
-            <para>Hibernate the system. This will trigger activation of
+            <para>Hibernate the system. This will trigger activation of the special target unit
-            the special <filename>hibernate.target</filename> target.
+            <filename>hibernate.target</filename>. This command is asynchronous, and will return after the hibernation
-            </para>
+            operation is successfully enqueued. It will not wait for the hibernate/thaw cycle to complete.</para>
           </listitem>
         </varlistentry>
 
@@ -1838,9 +1840,9 @@ Jan 12 10:46:45 example.com bluetoothd[8900]: gatt-time-server: Input/output err
           <term><command>hybrid-sleep</command></term>
 
           <listitem>
-            <para>Hibernate and suspend the system. This will trigger
+            <para>Hibernate and suspend the system. This will trigger activation of the special target unit
-            activation of the special
+            <filename>hybrid-sleep.target</filename>. This command is asynchronous, and will return after the hybrid
-            <filename>hybrid-sleep.target</filename> target.</para>
+            sleep operation is successfully enqueued. It will not wait for the sleep/wake-up cycle to complete.</para>
           </listitem>
         </varlistentry>
       </variablelist>

src/login/logind-dbus.c

@@ -1409,12 +1409,12 @@ static int bus_manager_log_shutdown(
         if (streq(unit_name, SPECIAL_POWEROFF_TARGET)) {
                 p = "MESSAGE=System is powering down";
                 q = "SHUTDOWN=power-off";
-        } else if (streq(unit_name, SPECIAL_HALT_TARGET)) {
-                p = "MESSAGE=System is halting";
-                q = "SHUTDOWN=halt";
         } else if (streq(unit_name, SPECIAL_REBOOT_TARGET)) {
                 p = "MESSAGE=System is rebooting";
                 q = "SHUTDOWN=reboot";
+        } else if (streq(unit_name, SPECIAL_HALT_TARGET)) {
+                p = "MESSAGE=System is halting";
+                q = "SHUTDOWN=halt";
         } else if (streq(unit_name, SPECIAL_KEXEC_TARGET)) {
                 p = "MESSAGE=System is rebooting with kexec";
                 q = "SHUTDOWN=kexec";
@@ -1822,6 +1822,20 @@ static int method_reboot(sd_bus_message *message, void *userdata, sd_bus_error *
                         error);
 }
 
+static int method_halt(sd_bus_message *message, void *userdata, sd_bus_error *error) {
+        Manager *m = userdata;
+
+        return method_do_shutdown_or_sleep(
+                        m, message,
+                        SPECIAL_HALT_TARGET,
+                        INHIBIT_SHUTDOWN,
+                        "org.freedesktop.login1.halt",
+                        "org.freedesktop.login1.halt-multiple-sessions",
+                        "org.freedesktop.login1.halt-ignore-inhibit",
+                        NULL,
+                        error);
+}
+
 static int method_suspend(sd_bus_message *message, void *userdata, sd_bus_error *error) {
         Manager *m = userdata;
 
@@ -1836,6 +1850,34 @@ static int method_suspend(sd_bus_message *message, void *userdata, sd_bus_error
                         error);
 }
 
+static int method_hibernate(sd_bus_message *message, void *userdata, sd_bus_error *error) {
+        Manager *m = userdata;
+
+        return method_do_shutdown_or_sleep(
+                        m, message,
+                        SPECIAL_HIBERNATE_TARGET,
+                        INHIBIT_SLEEP,
+                        "org.freedesktop.login1.hibernate",
+                        "org.freedesktop.login1.hibernate-multiple-sessions",
+                        "org.freedesktop.login1.hibernate-ignore-inhibit",
+                        "hibernate",
+                        error);
+}
+
+static int method_hybrid_sleep(sd_bus_message *message, void *userdata, sd_bus_error *error) {
+        Manager *m = userdata;
+
+        return method_do_shutdown_or_sleep(
+                        m, message,
+                        SPECIAL_HYBRID_SLEEP_TARGET,
+                        INHIBIT_SLEEP,
+                        "org.freedesktop.login1.hibernate",
+                        "org.freedesktop.login1.hibernate-multiple-sessions",
+                        "org.freedesktop.login1.hibernate-ignore-inhibit",
+                        "hybrid-sleep",
+                        error);
+}
+
 static int nologin_timeout_handler(
                         sd_event_source *s,
                         uint64_t usec,
@@ -1911,9 +1953,12 @@ fail:
 }
 
 static void reset_scheduled_shutdown(Manager *m) {
+        assert(m);
+
         m->scheduled_shutdown_timeout_source = sd_event_source_unref(m->scheduled_shutdown_timeout_source);
         m->wall_message_timeout_source = sd_event_source_unref(m->wall_message_timeout_source);
         m->nologin_timeout_source = sd_event_source_unref(m->nologin_timeout_source);
+
         m->scheduled_shutdown_type = mfree(m->scheduled_shutdown_type);
         m->scheduled_shutdown_timeout = 0;
         m->shutdown_dry_run = false;
@@ -1922,6 +1967,7 @@ static void reset_scheduled_shutdown(Manager *m) {
                 (void) unlink("/run/nologin");
                 m->unlink_nologin = false;
         }
+
         (void) unlink("/run/systemd/shutdown/scheduled");
 }
 
@@ -1940,12 +1986,14 @@ static int manager_scheduled_shutdown_handler(
         if (isempty(m->scheduled_shutdown_type))
                 return 0;
 
-        if (streq(m->scheduled_shutdown_type, "halt"))
+        if (streq(m->scheduled_shutdown_type, "poweroff"))
-                target = SPECIAL_HALT_TARGET;
-        else if (streq(m->scheduled_shutdown_type, "poweroff"))
                 target = SPECIAL_POWEROFF_TARGET;
-        else
+        else if (streq(m->scheduled_shutdown_type, "reboot"))
                 target = SPECIAL_REBOOT_TARGET;
+        else if (streq(m->scheduled_shutdown_type, "halt"))
+                target = SPECIAL_HALT_TARGET;
+        else
+                assert_not_reached("unexpected shutdown type");
 
         /* Don't allow multiple jobs being executed at the same time */
         if (m->action_what) {
@@ -1989,6 +2037,7 @@ static int method_schedule_shutdown(sd_bus_message *message, void *userdata, sd_
         uint64_t elapse;
         char *type;
         int r;
+        bool dry_run = false;
 
         assert(m);
         assert(message);
@@ -1999,10 +2048,14 @@ static int method_schedule_shutdown(sd_bus_message *message, void *userdata, sd_
 
         if (startswith(type, "dry-")) {
                 type += 4;
-                m->shutdown_dry_run = true;
+                dry_run = true;
         }
 
-        if (streq(type, "reboot")) {
+        if (streq(type, "poweroff")) {
+                action = "org.freedesktop.login1.power-off";
+                action_multiple_sessions = "org.freedesktop.login1.power-off-multiple-sessions";
+                action_ignore_inhibit = "org.freedesktop.login1.power-off-ignore-inhibit";
+        } else if (streq(type, "reboot")) {
                 action = "org.freedesktop.login1.reboot";
                 action_multiple_sessions = "org.freedesktop.login1.reboot-multiple-sessions";
                 action_ignore_inhibit = "org.freedesktop.login1.reboot-ignore-inhibit";
@@ -2010,10 +2063,6 @@ static int method_schedule_shutdown(sd_bus_message *message, void *userdata, sd_
                 action = "org.freedesktop.login1.halt";
                 action_multiple_sessions = "org.freedesktop.login1.halt-multiple-sessions";
                 action_ignore_inhibit = "org.freedesktop.login1.halt-ignore-inhibit";
-        } else if (streq(type, "poweroff")) {
-                action = "org.freedesktop.login1.power-off";
-                action_multiple_sessions = "org.freedesktop.login1.power-off-multiple-sessions";
-                action_ignore_inhibit = "org.freedesktop.login1.power-off-ignore-inhibit";
         } else
                 return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Unsupported shutdown type");
 
@@ -2043,6 +2092,8 @@ static int method_schedule_shutdown(sd_bus_message *message, void *userdata, sd_
                 return log_oom();
         }
 
+        m->shutdown_dry_run = dry_run;
+
         if (m->nologin_timeout_source) {
                 r = sd_event_source_set_time(m->nologin_timeout_source, elapse);
                 if (r < 0)
@@ -2114,34 +2165,6 @@ static int method_cancel_scheduled_shutdown(sd_bus_message *message, void *userd
         return sd_bus_reply_method_return(message, "b", cancelled);
 }
 
-static int method_hibernate(sd_bus_message *message, void *userdata, sd_bus_error *error) {
-        Manager *m = userdata;
-
-        return method_do_shutdown_or_sleep(
-                        m, message,
-                        SPECIAL_HIBERNATE_TARGET,
-                        INHIBIT_SLEEP,
-                        "org.freedesktop.login1.hibernate",
-                        "org.freedesktop.login1.hibernate-multiple-sessions",
-                        "org.freedesktop.login1.hibernate-ignore-inhibit",
-                        "hibernate",
-                        error);
-}
-
-static int method_hybrid_sleep(sd_bus_message *message, void *userdata, sd_bus_error *error) {
-        Manager *m = userdata;
-
-        return method_do_shutdown_or_sleep(
-                        m, message,
-                        SPECIAL_HYBRID_SLEEP_TARGET,
-                        INHIBIT_SLEEP,
-                        "org.freedesktop.login1.hibernate",
-                        "org.freedesktop.login1.hibernate-multiple-sessions",
-                        "org.freedesktop.login1.hibernate-ignore-inhibit",
-                        "hybrid-sleep",
-                        error);
-}
-
 static int method_can_shutdown_or_sleep(
                 Manager *m,
                 sd_bus_message *message,
@@ -2260,6 +2283,19 @@ static int method_can_reboot(sd_bus_message *message, void *userdata, sd_bus_err
                         error);
 }
 
+static int method_can_halt(sd_bus_message *message, void *userdata, sd_bus_error *error) {
+        Manager *m = userdata;
+
+        return method_can_shutdown_or_sleep(
+                        m, message,
+                        INHIBIT_SHUTDOWN,
+                        "org.freedesktop.login1.halt",
+                        "org.freedesktop.login1.halt-multiple-sessions",
+                        "org.freedesktop.login1.halt-ignore-inhibit",
+                        NULL,
+                        error);
+}
+
 static int method_can_suspend(sd_bus_message *message, void *userdata, sd_bus_error *error) {
         Manager *m = userdata;
 
@@ -2612,11 +2648,13 @@ const sd_bus_vtable manager_vtable[] = {
         SD_BUS_METHOD("FlushDevices", "b", NULL, method_flush_devices, SD_BUS_VTABLE_UNPRIVILEGED),
         SD_BUS_METHOD("PowerOff", "b", NULL, method_poweroff, SD_BUS_VTABLE_UNPRIVILEGED),
         SD_BUS_METHOD("Reboot", "b", NULL, method_reboot, SD_BUS_VTABLE_UNPRIVILEGED),
+        SD_BUS_METHOD("Halt", "b", NULL, method_halt, SD_BUS_VTABLE_UNPRIVILEGED),
         SD_BUS_METHOD("Suspend", "b", NULL, method_suspend, SD_BUS_VTABLE_UNPRIVILEGED),
         SD_BUS_METHOD("Hibernate", "b", NULL, method_hibernate, SD_BUS_VTABLE_UNPRIVILEGED),
         SD_BUS_METHOD("HybridSleep", "b", NULL, method_hybrid_sleep, SD_BUS_VTABLE_UNPRIVILEGED),
         SD_BUS_METHOD("CanPowerOff", NULL, "s", method_can_poweroff, SD_BUS_VTABLE_UNPRIVILEGED),
         SD_BUS_METHOD("CanReboot", NULL, "s", method_can_reboot, SD_BUS_VTABLE_UNPRIVILEGED),
+        SD_BUS_METHOD("CanHalt", NULL, "s", method_can_halt, SD_BUS_VTABLE_UNPRIVILEGED),
         SD_BUS_METHOD("CanSuspend", NULL, "s", method_can_suspend, SD_BUS_VTABLE_UNPRIVILEGED),
         SD_BUS_METHOD("CanHibernate", NULL, "s", method_can_hibernate, SD_BUS_VTABLE_UNPRIVILEGED),
         SD_BUS_METHOD("CanHybridSleep", NULL, "s", method_can_hybrid_sleep, SD_BUS_VTABLE_UNPRIVILEGED),

src/login/org.freedesktop.login1.conf

@@ -132,6 +132,10 @@
                        send_interface="org.freedesktop.login1.Manager"
                        send_member="Reboot"/>
 
+                <allow send_destination="org.freedesktop.login1"
+                       send_interface="org.freedesktop.login1.Manager"
+                       send_member="Halt"/>
+
                 <allow send_destination="org.freedesktop.login1"
                        send_interface="org.freedesktop.login1.Manager"
                        send_member="Suspend"/>
@@ -152,6 +156,10 @@
                        send_interface="org.freedesktop.login1.Manager"
                        send_member="CanReboot"/>
 
+                <allow send_destination="org.freedesktop.login1"
+                       send_interface="org.freedesktop.login1.Manager"
+                       send_member="CanHalt"/>
+
                 <allow send_destination="org.freedesktop.login1"
                        send_interface="org.freedesktop.login1.Manager"
                        send_member="CanSuspend"/>

src/login/org.freedesktop.login1.policy.in

@@ -218,6 +218,39 @@
                 <annotate key="org.freedesktop.policykit.imply">org.freedesktop.login1.reboot</annotate>
         </action>
 
+        <action id="org.freedesktop.login1.halt">
+                <_description>Halt the system</_description>
+                <_message>Authentication is required for halting the system.</_message>
+                <defaults>
+                        <allow_any>auth_admin_keep</allow_any>
+                        <allow_inactive>auth_admin_keep</allow_inactive>
+                        <allow_active>auth_admin_keep</allow_active>
+                </defaults>
+                <annotate key="org.freedesktop.policykit.imply">org.freedesktop.login1.set-wall-message</annotate>
+        </action>
+
+        <action id="org.freedesktop.login1.halt-multiple-sessions">
+                <_description>Halt the system while other users are logged in</_description>
+                <_message>Authentication is required for halting the system while other users are logged in.</_message>
+                <defaults>
+                        <allow_any>auth_admin_keep</allow_any>
+                        <allow_inactive>auth_admin_keep</allow_inactive>
+                        <allow_active>auth_admin_keep</allow_active>
+                </defaults>
+                <annotate key="org.freedesktop.policykit.imply">org.freedesktop.login1.halt</annotate>
+        </action>
+
+        <action id="org.freedesktop.login1.halt-ignore-inhibit">
+                <_description>Halt the system while an application asked to inhibit it</_description>
+                <_message>Authentication is required for halting the system while an application asked to inhibit it.</_message>
+                <defaults>
+                        <allow_any>auth_admin_keep</allow_any>
+                        <allow_inactive>auth_admin_keep</allow_inactive>
+                        <allow_active>auth_admin_keep</allow_active>
+                </defaults>
+                <annotate key="org.freedesktop.policykit.imply">org.freedesktop.login1.halt</annotate>
+        </action>
+
         <action id="org.freedesktop.login1.suspend">
                 <_description>Suspend the system</_description>
                 <_message>Authentication is required for suspending the system.</_message>

src/systemctl/systemctl.c

@@ -3267,14 +3267,19 @@ static int logind_reboot(enum action a) {
 
         switch (a) {
 
+        case ACTION_POWEROFF:
+                method = "PowerOff";
+                description = "power off system";
+                break;
+
         case ACTION_REBOOT:
                 method = "Reboot";
                 description = "reboot system";
                 break;
 
-        case ACTION_POWEROFF:
+        case ACTION_HALT:
-                method = "PowerOff";
+                method = "Halt";
-                description = "power off system";
+                description = "halt system";
                 break;
 
         case ACTION_SUSPEND:
@@ -3568,6 +3573,7 @@ static int start_special(int argc, char *argv[], void *userdata) {
                 if (IN_SET(a,
                            ACTION_POWEROFF,
                            ACTION_REBOOT,
+                           ACTION_HALT,
                            ACTION_SUSPEND,
                            ACTION_HIBERNATE,
                            ACTION_HYBRID_SLEEP)) {
@@ -3579,8 +3585,16 @@ static int start_special(int argc, char *argv[], void *userdata) {
                                 /* requested operation is not supported or already in progress */
                                 return r;
 
-                        /* On all other errors, try low-level operation */
+                        /* On all other errors, try low-level operation. In order to minimize the difference between
-                }
+                         * operation with and without logind, we explicitly enable non-blocking mode for this, as
+                         * logind's shutdown operations are always non-blocking. */
+
+                        arg_no_block = true;
+
+                } else if (IN_SET(a, ACTION_EXIT, ACTION_KEXEC))
+                        /* Since exit/kexec are so close in behaviour to power-off/reboot, let's also make them
+                         * asynchronous, in order to not confuse the user needlessly with unexpected behaviour. */
+                        arg_no_block = true;
 
                 r = start_unit(argc, argv, userdata);
         }
@@ -8503,7 +8517,7 @@ static int halt_main(void) {
                 /* Try logind if we are a normal user and no special
                  * mode applies. Maybe PolicyKit allows us to shutdown
                  * the machine. */
-                if (IN_SET(arg_action, ACTION_POWEROFF, ACTION_REBOOT)) {
+                if (IN_SET(arg_action, ACTION_POWEROFF, ACTION_REBOOT, ACTION_HALT)) {
                         r = logind_reboot(arg_action);
                         if (r >= 0)
                                 return r;