logind: respect "delay" inhibitors in scheduled shutdowns

There is no justification not to wait an extra (default) 5 seconds, for
a more graceful shutdown of user programs.  Again, you don't get to ignore
delay inhibitors for unscheduled shutdowns, short of
`systemctl poweroff -f`.

It is simplest if we move the test for `m->shutdown_dry_run` into
manager_scheduled_shutdown_handler().

However we need to not add such delays during a "dry run".  Otherwise, we
would still have to be considered "in progress" for some seconds after our
admin has seen the final wall message.  If they go to `poweroff`, we would
have blocked them with a misleading error message.  Note this `poweroff`
will still process delay inhibitors as needed.  If the admin planned to
use a more forceful method... eh.  It's their responsibility to assess
whether that's safe.

There is an argument that the alternative behaviour could be used (racily!)
to kludge around them not being able to shutdown to "single user mode".  If
we cared about that case, we would have easily preserved non-racy support
for it in `shutdown`.

Additionally, though I think this code does read more easily by reducing
inconsistencies, we didn't come up with any use case for delay inhibitors
v.s. shutdown.[1]  The SIGTERM v.s. SIGKILL delay is more general, and we
allow a whole 90 seconds for it, not just 5.  So I don't think keeping this
approach bears a risk of significant damage.

[1] https://www.freedesktop.org/wiki/Software/elogind/inhibit/

diff --git a/src/login/logind-dbus.c b/src/login/logind-dbus.c
index 3e231ac3df2e44ced7d306ecb6b4e4f258924a18..99a34f29a2b25c911759e83bae833276404c1dcc 100644 (file)
--- a/src/login/logind-dbus.c
+++ b/src/login/logind-dbus.c
@@ -1415,7 +1415,6 @@ static int have_multiple_sessions(
 #if 0 /// elogind has its own variant in elogind-dbus.c
 static int bus_manager_log_shutdown(
                 Manager *m,
-                InhibitWhat w,
                 const char *unit_name) {
 
         const char *p, *q;
@@ -1423,9 +1422,6 @@ static int bus_manager_log_shutdown(
         assert(m);
         assert(unit_name);
 
-        if (w != INHIBIT_SHUTDOWN)
-                return 0;
-
         if (streq(unit_name, SPECIAL_POWEROFF_TARGET)) {
                 p = "MESSAGE=System is powering down";
                 q = "SHUTDOWN=power-off";
@@ -1501,20 +1497,6 @@ int manager_set_lid_switch_ignore(Manager *m, usec_t until) {
         return r;
 }
 
-static void reset_scheduled_shutdown(Manager *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;
-
-        if (m->unlink_nologin) {
-                (void) unlink("/run/nologin");
-                m->unlink_nologin = false;
-        }
-}
-
 #if 0 /// elogind has its own variant in elogind-dbus.c
 static int execute_shutdown_or_sleep(
                 Manager *m,
@@ -1532,32 +1514,28 @@ static int execute_shutdown_or_sleep(
         assert(w < _INHIBIT_WHAT_MAX);
         assert(unit_name);
 
-        bus_manager_log_shutdown(m, w, unit_name);
+        if (w == INHIBIT_SHUTDOWN)
+                bus_manager_log_shutdown(m, unit_name);
 
-        if (m->shutdown_dry_run) {
-                log_info("Running in dry run, suppressing action.");
-                reset_scheduled_shutdown(m);
-        } else {
-                r = sd_bus_call_method(
-                                m->bus,
-                                "org.freedesktop.systemd1",
-                                "/org/freedesktop/systemd1",
-                                "org.freedesktop.systemd1.Manager",
-                                "StartUnit",
-                                error,
-                                &reply,
-                                "ss", unit_name, "replace-irreversibly");
-                if (r < 0)
-                        return r;
+        r = sd_bus_call_method(
+                        m->bus,
+                        "org.freedesktop.systemd1",
+                        "/org/freedesktop/systemd1",
+                        "org.freedesktop.systemd1.Manager",
+                        "StartUnit",
+                        error,
+                        &reply,
+                        "ss", unit_name, "replace-irreversibly");
+        if (r < 0)
+                return r;
 
-                r = sd_bus_message_read(reply, "o", &p);
-                if (r < 0)
-                        return r;
+        r = sd_bus_message_read(reply, "o", &p);
+        if (r < 0)
+                return r;
 
-                c = strdup(p);
-                if (!c)
-                        return -ENOMEM;
-        }
+        c = strdup(p);
+        if (!c)
+                return -ENOMEM;
 
         m->action_unit = unit_name;
         free(m->action_job);
@@ -1971,6 +1949,21 @@ fail:
 }
 
 #if 0 /// elogind has its own variant in elogind-dbus.c
+static void reset_scheduled_shutdown(Manager *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;
+
+        if (m->unlink_nologin) {
+                (void) unlink("/run/nologin");
+                m->unlink_nologin = false;
+        }
+        (void) unlink("/run/systemd/shutdown/scheduled");
+}
+
 static int manager_scheduled_shutdown_handler(
                         sd_event_source *s,
                         uint64_t usec,
@@ -1999,7 +1992,20 @@ static int manager_scheduled_shutdown_handler(
                 return -EALREADY;
         }
 
-        r = execute_shutdown_or_sleep(m, INHIBIT_SHUTDOWN, target, &error);
+        if (m->shutdown_dry_run) {
+                /* We do not process delay inhibitors here.  Otherwise, we
+                 * would have to be considered "in progress" (like the check
+                 * above) for some seconds after our admin has seen the final
+                 * wall message. */
+
+                bus_manager_log_shutdown(m, target);
+                log_info("Running in dry run, suppressing action.");
+                reset_scheduled_shutdown(m);
+
+                return 0;
+        }
+
+        r = bus_manager_shutdown_or_sleep_now_or_later(m, target, INHIBIT_SHUTDOWN, &error);
         if (r < 0)
                 return log_error_errno(r, "Scheduled shutdown to %s failed: %m", target);